PDC bits: What`s needed to meet tomorrow`s challenge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warren, T.M.; Sinor, L.A.

1994-12-31

When polycrystalline diamond compact (PDC) bits were introduced in the mid-1970s they showed tantalizingly high penetration rates in laboratory drilling tests. Single cutter tests indicated that they had the potential to drill very hard rocks. Unfortunately, 20 years later we`re still striving to reach the potential that these bits seem to have. Many problems have been overcome, and PDC bits have offered capabilities not possible with roller cone bits. PDC bits provide the most economical bit choice in many areas, but their limited durability has hampered their application in many other areas.

New PDC bit design reduces vibrational problems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mensa-Wilmot, G.; Alexander, W.L.

1995-05-22

A new polycrystalline diamond compact (PDC) bit design combines cutter layout, load balancing, unsymmetrical blades and gauge pads, and spiraled blades to reduce problematic vibrations without limiting drilling efficiency. Stabilization improves drilling efficiency and also improves dull characteristics for PDC bits. Some PDC bit designs mitigate one vibrational mode (such as bit whirl) through drilling parameter manipulation yet cause or excite another vibrational mode (such as slip-stick). An alternative vibration-reducing concept which places no limitations on the operational environment of a PDC bit has been developed to ensure optimization of the bit`s available mechanical energy. The paper discusses bit stabilization,more » vibration reduction, vibration prevention, cutter arrangement, load balancing, blade layout, spiraled blades, and bit design.« less

Quantum measurement of a rapidly rotating spin qubit in diamond.

PubMed

Wood, Alexander A; Lilette, Emmanuel; Fein, Yaakov Y; Tomek, Nikolas; McGuinness, Liam P; Hollenberg, Lloyd C L; Scholten, Robert E; Martin, Andy M

2018-05-01

A controlled qubit in a rotating frame opens new opportunities to probe fundamental quantum physics, such as geometric phases in physically rotating frames, and can potentially enhance detection of magnetic fields. Realizing a single qubit that can be measured and controlled during physical rotation is experimentally challenging. We demonstrate quantum control of a single nitrogen-vacancy (NV) center within a diamond rotated at 200,000 rpm, a rotational period comparable to the NV spin coherence time T 2 . We stroboscopically image individual NV centers that execute rapid circular motion in addition to rotation and demonstrate preparation, control, and readout of the qubit quantum state with lasers and microwaves. Using spin-echo interferometry of the rotating qubit, we are able to detect modulation of the NV Zeeman shift arising from the rotating NV axis and an external DC magnetic field. Our work establishes single NV qubits in diamond as quantum sensors in the physically rotating frame and paves the way for the realization of single-qubit diamond-based rotation sensors.

Quantum measurement of a rapidly rotating spin qubit in diamond

PubMed Central

Fein, Yaakov Y.; Hollenberg, Lloyd C. L.; Scholten, Robert E.

2018-01-01

A controlled qubit in a rotating frame opens new opportunities to probe fundamental quantum physics, such as geometric phases in physically rotating frames, and can potentially enhance detection of magnetic fields. Realizing a single qubit that can be measured and controlled during physical rotation is experimentally challenging. We demonstrate quantum control of a single nitrogen-vacancy (NV) center within a diamond rotated at 200,000 rpm, a rotational period comparable to the NV spin coherence time T2. We stroboscopically image individual NV centers that execute rapid circular motion in addition to rotation and demonstrate preparation, control, and readout of the qubit quantum state with lasers and microwaves. Using spin-echo interferometry of the rotating qubit, we are able to detect modulation of the NV Zeeman shift arising from the rotating NV axis and an external DC magnetic field. Our work establishes single NV qubits in diamond as quantum sensors in the physically rotating frame and paves the way for the realization of single-qubit diamond-based rotation sensors. PMID:29736417

Wear and performance: An experimental study on PDC bits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Villa, O.; Azar, J.J.

1997-07-01

Real-time drilling data, gathered under full-scale conditions, was analyzed to determine the influence of cutter dullness on PDC-bit rate of penetration. It was found that while drilling in shale, the cutters` wearflat area was not a controlling factor on rate of penetration; however, when drilling in limestone, wearflat area significantly influenced PDC bit penetration performance. Similarly, the presence of diamond lips on PDC cutters was found to be unimportant while drilling in shale, but it greatly enhanced bit performance when drilling in limestone.

Ultrasonic rotary-hammer drill

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph (Inventor); Badescu, Mircea (Inventor); Sherrit, Stewart (Inventor); Kassab, Steve (Inventor); Bao, Xiaoqi (Inventor)

2010-01-01

A mechanism for drilling or coring by a combination of sonic hammering and rotation. The drill includes a hammering section with a set of preload weights mounted atop a hammering actuator and an axial passage through the hammering section. In addition, a rotary section includes a motor coupled to a drive shaft that traverses the axial passage through the hammering section. A drill bit is coupled to the drive shaft for drilling by a combination of sonic hammering and rotation. The drill bit includes a fluted shaft leading to a distal crown cutter with teeth. The bit penetrates sampled media by repeated hammering action. In addition, the bit is rotated. As it rotates the fluted bit carries powdered cuttings helically upward along the side of the bit to the surface.

Confined compressive strength analysis can improve PDC bit selection. [Polycrystalline Diamond Compact

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fabain, R.T.

1994-05-16

A rock strength analysis program, through intensive log analysis, can quantify rock hardness in terms of confined compressive strength to identify intervals suited for drilling with polycrystalline diamond compact (PDC) bits. Additionally, knowing the confined compressive strength helps determine the optimum PDC bit for the intervals. Computing rock strength as confined compressive strength can more accurately characterize a rock's actual hardness downhole than other methods. the information can be used to improve bit selections and to help adjust drilling parameters to reduce drilling costs. Empirical data compiled from numerous field strength analyses have provided a guide to selecting PDC drillmore » bits. A computer analysis program has been developed to aid in PDC bit selection. The program more accurately defines rock hardness in terms of confined strength, which approximates the in situ rock hardness downhole. Unconfined compressive strength is rock hardness at atmospheric pressure. The program uses sonic and gamma ray logs as well as numerous input data from mud logs. Within the range of lithologies for which the program is valid, rock hardness can be determine with improved accuracy. The program's output is typically graphed in a log format displaying raw data traces from well logs, computer-interpreted lithology, the calculated values of confined compressive strength, and various optional rock mechanic outputs.« less

Proper nozzle location, bit profile, and cutter arrangement affect PDC-bit performance significantly

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcia-Gavito, D.; Azar, J.J.

1994-09-01

During the past 20 years, the drilling industry has looked to new technology to halt the exponentially increasing costs of drilling oil, gas, and geothermal wells. This technology includes bit design innovations to improve overall drilling performance and reduce drilling costs. These innovations include development of drag bits that use PDC cutters, also called PDC bits, to drill long, continuous intervals of soft to medium-hard formations more economically than conventional three-cone roller-cone bits. The cost advantage is the result of higher rates of penetration (ROP's) and longer bit life obtained with the PDC bits. An experimental study comparing the effectsmore » of polycrystalline-diamond-compact (PDC)-bit design features on the dynamic pressure distribution at the bit/rock interface was conducted on a full-scale drilling rig. Results showed that nozzle location, bit profile, and cutter arrangement are significant factors in PDC-bit performance.« less

New PDC bit optimizes drilling performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Besson, A.; Gudulec, P. le; Delwiche, R.

1996-05-01

The lithology in northwest Argentina contains a major section where polycrystalline diamond compact (PDC) bits have not succeeded in the past. The section consists of dense shales and cemented sandstone stringers with limestone laminations. Conventional PDC bits experienced premature failures in the section. A new generation PDC bit tripled rate of penetration (ROP) and increased by five times the potential footage per bit. Recent improvements in PDC bit technology that enabled the improved performance include: the ability to control the PDC cutter quality; use of an advanced cutter lay out defined by 3D software; using cutter face design code formore » optimized cleaning and cooling; and, mastering vibration reduction features, including spiraled blades.« less

PDC-bit performance under simulated borehole conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, E.E.; Azar, J.J.

1993-09-01

Laboratory drilling tests were used to investigate the effects of pressure on polycrystalline-diamond-compact (PDC) drill-bit performance. Catoosa shale core samples were drilled with PDC and roller-cone bits at up to 1,750-psi confining pressure. All tests were conducted in a controlled environment with a full-scale laboratory drilling system. Test results indicate, that under similar operating conditions, increases in confining pressure reduce PDC-bit performance as much as or more than conventional-rock-bit performance. Specific energy calculations indicate that a combination of rock strength, chip hold-down, and bit balling may have reduced performance. Quantifying the degree to which pressure reduces PDC-bit performance will helpmore » researchers interpret test results and improve bit designs and will help drilling engineers run PDC bits more effectively in the field.« less

Grinding tool for making hemispherical bores in hard materials

DOEpatents

Duran, E.L.

1985-04-03

A grinding tool for forming hemispherical bores in hard materials such as boron carbide. The tool comprises a hemicircular grinding bit, formed of a metal bond diamond matrix, which is mounted transversely on one end of a tubular tool shaft. The bit includes a spherically curved outer edge surface which is the active grinding surface of the tool. Two coolant fluid ports on opposite sides of the bit enable introduction of coolant fluid through the bore of the tool shaft so as to be emitted adjacent the opposite sides of the grinding bit, thereby providing optimum cooling of both the workpiece and the bit.

High-Density Near-Field Readout Using Diamond Solid Immersion Lens

NASA Astrophysics Data System (ADS)

Shinoda, Masataka; Saito, Kimihiro; Kondo, Takao; Nakaoki, Ariyoshi; Furuki, Motohiro; Takeda, Minoru; Yamamoto, Masanobu; Schaich, Thomas J.; van Oerle, Bart M.; Godfried, Herman P.; Kriele, Paul A. C.; Houwman, Evert P.; Nelissen, Wim H. M.; Pels, Gert J.; Spaaij, Paul G. M.

2006-02-01

We investigated high-density near-field readout using a diamond solid immersion lens (SIL). A synthetic single-crystal chemical vapor deposition diamond provides a high refractive index and a high transmission for a wide wavelength range. Since the refractive index at a wavelength of 405 nm is 2.458, we could design a solid immersion lens with an effective numerical aperture of 2.34. Using the diamond SIL, we observed the eye pattern of a 150-GB-capacity (104.3 Gbit/in.2) disk with a track pitch of 130 nm and a bit length of 47.6 nm.

2017 Total Solar Eclipse

NASA Image and Video Library

2017-08-21

The diamond-ring effect occurred at the beginning and end of totality during a total solar eclipse. As the last bits of sunlight pass through the valleys on the moon's limb, and the faint corona around the sun is just becoming visible, it looks like a ring with glittering diamonds on it. Credit: (NASA/Carla Thomas)

New PDC cutters improve drilling efficiency

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mensa-Wilmot, G.

1997-10-27

New polycrystalline diamond compact (PDC) cutters increase penetration rates and cumulative footage through improved abrasion, impact, interface strength, thermal stability, and fatigue characteristics. Studies of formation characterization, vibration analysis, hydraulic layouts, and bit selection continue to improve and expand PDC bit applications. The paper discusses development philosophy, performance characteristics and requirements, Types A, B, and C cutters, and combinations.

Strong coupling between a single nitrogen-vacancy spin and the rotational mode of diamonds levitating in an ion trap

NASA Astrophysics Data System (ADS)

Delord, T.; Nicolas, L.; Chassagneux, Y.; Hétet, G.

2017-12-01

A scheme for strong coupling between a single atomic spin and the rotational mode of levitating nanoparticles is proposed. The idea is based on spin readout of nitrogen-vacancy centers embedded in aspherical nanodiamonds levitating in an ion trap. We show that the asymmetry of the diamond induces a rotational confinement in the ion trap. Using a weak homogeneous magnetic field and a strong microwave driving we then demonstrate that the spin of the nitrogen-vacancy center can be strongly coupled to the rotational mode of the diamond.

Single photon quantum cryptography.

PubMed

Beveratos, Alexios; Brouri, Rosa; Gacoin, Thierry; Villing, André; Poizat, Jean-Philippe; Grangier, Philippe

2002-10-28

We report the full implementation of a quantum cryptography protocol using a stream of single photon pulses generated by a stable and efficient source operating at room temperature. The single photon pulses are emitted on demand by a single nitrogen-vacancy color center in a diamond nanocrystal. The quantum bit error rate is less that 4.6% and the secure bit rate is 7700 bits/s. The overall performances of our system reaches a domain where single photons have a measurable advantage over an equivalent system based on attenuated light pulses.

Laboratory Investigations for the Role of Flushing Media in Diamond Drilling of Marble

NASA Astrophysics Data System (ADS)

Bhatnagar, A.; Khandelwal, Manoj; Rao, K. U. M.

2011-05-01

Marble is used as a natural stone for decorative purposes from ages. Marble is a crystalline rock, composed predominantly of calcite, dolomite or serpentine. The presence of impurities imparts decorative pattern and colors. The diamond-based operations are extensively used in the mining and processing of marble. Marble is mined out in the form of blocks of cuboids shape and has to undergo extensive processing to make it suitable for the end users. The processing operation includes slabbing, sizing, polishing, etc. Diamond drilling is also commonly used for the exploration of different mineral deposits throughout the world. In this paper an attempt has been made to enhance the performance of diamond drilling on marble rocks by adding polyethylene-oxide (PEO) in the flushing water. The effect of PEO added with the drilling water was studied by varying different machine parameters and flushing media concentration in the laboratory. The responses were rate of penetration and torque at bit-rock interface. Different physico-mechanical properties of marble were also determined. It was found that flushing water added with PEO can substantially enhance the penetration rates and reduce the torque developed at the bit-rock interface as compared to plain flushing water.

The study of microstructure of wear-resistant coatings applied for protection from abrasive wear of horizontal and tilt drilling drill bits

NASA Astrophysics Data System (ADS)

Markova, I. Yu; Zakharova, E. S.; Maslov, A. L.; Polushin, N. I.; Laptev, A. I.; SOvchinnikova, M.

2017-05-01

Drill bits of the cutting type over the period of their existence have undergone significant changes - from the use of carbide cutters to diamond composite PDC elements, in which the diamond layer is applied to a hardmetal substrate. Using such elements, it was possible to significantly increase the service life of the drill bits, however, during work, there is a significant abrasive deterioration of the bit body, which does not fully realize the advantages of PDC elements. Therefore, to protect the body from wear use special wear-resistant coatings. This work is devoted to research of microstructural coatings, namely coatings brands WokaDur NiA, HR-6750, HR-6750 with sublayer Rock Dur 47 on various steel substrates which applied by the gas-thermal spraying in Ltd “Oerlikon Metko Rus”. They were examined with the use of scanning electron microscopy, X-ray phase analysis and a Vickers micro-hardness tester. It was established that the microhardness of the coating matrix is 590-660 HV, and the microhardness of tungsten carbide particles reinforcing the coating, is 2145-2455 HV.

PDC bit hydraulics design, profile are key to reducing balling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hariharan, P.R.; Azar, J.J.

1996-12-09

Polycrystalline diamond compact (PDC) bits with a parabolic profile and bladed hydraulic design have a lesser tendency to ball during drilling of reactive shales. PDC bits with ribbed or open-face hydraulic designs and those with flat or rounded profiles tended to ball more often in the bit balling experiments conducted. Experimental work also indicates that PDC hydraulic design seems to have a greater influence on bit balling tendency compared to bit profile design. There are five main factors that affect bit balling: formation type, drilling fluid, drilling hydraulics, bit design, and confining pressures. An equation for specific energy showed thatmore » it could be used to describe the efficiency of the drilling process by examining the amount of energy spent in drilling a unit volume of rock. This concept of specific energy has been used herein to correlate with the parameter Rd, a parameter to quantify the degree of balling.« less

Characterization of oxygen defects in diamond by means of density functional theory calculations

NASA Astrophysics Data System (ADS)

Thiering, Gergő; Gali, Adam

2016-09-01

Point defects in diamond are of high interest as candidates for realizing solid state quantum bits, bioimaging agents, or ultrasensitive electric or magnetic field sensors. Various artificial diamond synthesis methods should introduce oxygen contamination in diamond, however, the incorporation of oxygen into diamond crystal and the nature of oxygen-related point defects are largely unknown. Oxygen may be potentially interesting as a source of quantum bits or it may interact with other point defects which are well established solid state qubits. Here we employ plane-wave supercell calculations within density functional theory, in order to characterize the electronic and magneto-optical properties of various oxygen-related defects. Besides the trivial single interstitial and substitutional oxygen defects we also consider their complexes with vacancies and hydrogen atoms. We find that oxygen defects are mostly electrically active and introduce highly correlated orbitals that pose a challenge for density functional theory modeling. Nevertheless, we are able to identify the fingerprints of substitutional oxygen defect, the oxygen-vacancy and oxygen-vacancy-hydrogen complexes in the electron paramagnetic resonance spectrum. We demonstrate that first principles calculations can predict the motional averaging of the electron paramagnetic resonance spectrum of defects that are subject to Jahn-Teller distortion. We show that the high-spin neutral oxygen-vacancy defect exhibits very fast nonradiative decay from its optical excited state that might hinder applying it as a qubit.

Turbodrills and innovative PDC bits economically drilled hard formations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boudreaux, R.C.; Massey, K.

1994-03-28

The use of turbodrills and polycrystalline diamond compact (PDC) bits with an innovative, tracking cutting structure has improved drilling economics in medium and hard formations in the Gulf of Mexico. Field results have confirmed that turbodrilling with trackset PDC bits reduced drilling costs, compared to offset wells. The combination of turbodrills and trackset bits has been used successfully in a broad range of applications and with various drilling parameters. Formations ranging from medium shales to hard, abrasive sands have been successfully and economically drilled. The tools have been used in both water-based and oil-based muds. Additionally, the turbo-drill and tracksetmore » PDC bit combination has been stable on directional drilling applications. The locking effect of the cutting structure helps keep the bit on course.« less

Remote drill bit loader

DOEpatents

Dokos, J.A.

1997-12-30

A drill bit loader is described for loading a tapered shank of a drill bit into a similarly tapered recess in the end of a drill spindle. The spindle has a transverse slot at the inner end of the recess. The end of the tapered shank of the drill bit has a transverse tang adapted to engage in the slot so that the drill bit will be rotated by the spindle. The loader is in the form of a cylinder adapted to receive the drill bit with the shank projecting out of the outer end of the cylinder. Retainer pins prevent rotation of the drill bit in the cylinder. The spindle is lowered to extend the shank of the drill bit into the recess in the spindle and the spindle is rotated to align the slot in the spindle with the tang on the shank. A spring unit in the cylinder is compressed by the drill bit during its entry into the recess of the spindle and resiliently drives the tang into the slot in the spindle when the tang and slot are aligned. 5 figs.

Remote drill bit loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dokos, J.A.

A drill bit loader is described for loading a tapered shank of a drill bit into a similarly tapered recess in the end of a drill spindle. The spindle has a transverse slot at the inner end of the recess. The end of the tapered shank of the drill bit has a transverse tang adapted to engage in the slot so that the drill bit will be rotated by the spindle. The loader is in the form of a cylinder adapted to receive the drill bit with the shank projecting out of the outer end of the cylinder. Retainer pinsmore » prevent rotation of the drill bit in the cylinder. The spindle is lowered to extend the shank of the drill bit into the recess in the spindle and the spindle is rotated to align the slot in the spindle with the tang on the shank. A spring unit in the cylinder is compressed by the drill bit during its entry into the recess of the spindle and resiliently drives the tang into the slot in the spindle when the tang and slot are aligned. 5 figs.« less

PDC cutters improve drilling in harsh environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mensa-Wilmot, G.

2000-02-01

Improvements in polycrystalline diamond compact (PDC) cutter technology have contributed immensely to the industry's acceptance of PDC bits as effective drilling tools. These cutters are being engineered to address the needs and requirements of different drilling programs. Extensive research and developments efforts have been dedicated to the analysis of the diamond table/tungsten carbide interface. The paper describes PDC cutter development, operational challenges, offset performance, and field experiences.

Formation of nanodiamond films from aqueous suspensions during spin coating

NASA Astrophysics Data System (ADS)

Lebedev-Stepanov, P. V.; Molchanov, S. P.; Vasil'ev, A. L.; Mitrokhin, V. P.; Yurasik, G. A.; Aleksenskii, A. E.; Dideikin, A. T.

2016-03-01

The formation of multifunctional ordered arrays of detonation diamond particles is studied during self-assembling in spin coating of films of evaporating microdroplets. It is shown that the most homogeneous layer of diamond particles on a crystalline silicon substrate forms at a rate of substrate rotation of 8000 min-1, whereas a relation between the distribution of particles and the radius is clearly detected at rates of about 2000 min-1. As the rate of substrate rotation increases from 2500 to 8000 min-1, the density of the coating of a silicon substrate with diamond nanoparticles decreases approximately threefold. A model is proposed to estimate the increase in the number of individual diamond "points" with the substrate rotation frequency.

Measurement and analysis of chatter in a compliant model of a drillstring equipped with a PDC bit

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elsayed, M.A.; Raymond, D.W.

1999-11-09

Typical laboratory testing of Polycrystalline Diamond Compact (PDC) bits is performed on relatively rigid setups. Even in hard rock, PDC bits exhibit reasonable life using such testing schemes. Unfortunately, field experience indicates otherwise. In this paper, the authors show that introducing compliance in testing setups provides better simulation of actual field conditions. Using such a scheme, they show that chatter can be severe even in softer rock, such as sandstone, and very destructive to the cutters in hard rock, such as sierra white granite.

Coal-Sizing Auger

NASA Technical Reports Server (NTRS)

Lewis, E. V.

1985-01-01

Aft end of auger, like forward, face-piercing end, equipped with hard cutting bits such as diamonds. As auger breaks face, pulls broken coal lumps into jaws and forces them into hardened throat section. There, cutting bits chew up lumps: Clearance between throat and auger shaft sets maximum size for coal particles that pass through. Auger motion pushes coal particles into mixing chamber, where paddles combine them with water.

About creation of machines for rock destruction with formation of apertures of various cross-sections

NASA Astrophysics Data System (ADS)

Zhukov, I. A.; Dvornikov, L. T.; Nikitenko, S. M.

2016-04-01

The article presents the results of the experimental research of the high strength rock destruction by a bladeless tool. Rational circuit designs of disposing of indenters in the impact part of the drill bits and a diamond tool are justified. New constructive solutions of reinforcing bladeless drill bits, which allow drilling blast-holes of the various cross-section, are shown.

Design Consideration and Performance of Networked Narrowband Waveforms for Tactical Communications

DTIC Science & Technology

2010-09-01

four proposed CPM modes, with perfect acquisition parameters, for both coherent and noncoherent detection using an iterative receiver with both inner...Figure 1: Bit error rate performance of various CPM modes with coherent and noncoherent detection. Figure 3 shows the corresponding relationship...symbols. Table 2 summarises the parameter Coherent results (cross) Noncoherent results (diamonds) Figur 1: Bit Error Rate Pe f rmance of

Triphasic Composite And Method Of Making Same

DOEpatents

Kear, Bernard H.; Sadangi, Rajendra K.; McCandlish, Larry E.; Voronov, Oleg

2000-07-18

A method for fabricating a triphasic composite such as a WC/Co/diamond composite with a high volume fraction of diamond in a WC/Co matrix. The method involves sintering of a WC/Co powder compact to develop a porous preform, which displays some rigidity and strength, infiltrating the porous preform with a controlled distribution of carbon, and high pressure/high temperature treatment of the carbon-containing WC/Co preform to transform the carbon to diamond. The distribution of diamond in the composite can be functionally graded to provide a WC/Co core and a diamond-enriched surface, wherein all three phases form an interconnected structure in three dimensions. Such a tricontinuous structure combines high strength and toughness with superior wear resistance, making it attractive for applications in machine tools and drill bits.

Percussive Augmenter of Rotary Drills for Operating as a Rotary-Hammer Drill

NASA Technical Reports Server (NTRS)

Aldrich, Jack Barron (Inventor); Bar-Cohen, Yoseph (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bao, Xiaoqi (Inventor); Scott, James Samson (Inventor)

2014-01-01

A percussive augmenter bit includes a connection shaft for mounting the bit onto a rotary drill. In a first modality, an actuator percussively drives the bit, and an electric slip-ring provides power to the actuator while being rotated by the drill. Hammering action from the actuator and rotation from the drill are applied directly to material being drilled. In a second modality, a percussive augmenter includes an actuator that operates as a hammering mechanism that drives a free mass into the bit creating stress pulses that fracture material that is in contact with the bit.

Ab initio theory of spin-orbit coupling for quantum bits in diamond exhibiting dynamic Jahn-Teller effect

NASA Astrophysics Data System (ADS)

Gali, Adam; Thiering, Gergő

Dopants in solids are promising candidates for implementations of quantum bits for quantum computing. In particular, the high-spin negatively charged nitrogen-vacancy defect (NV) in diamond has become a leading contender in solid-state quantum information processing. The initialization and readout of the spin is based on the spin-selective decay of the photo-excited electron to the ground state which is mediated by spin-orbit coupling between excited states states and phonons. Generally, the spin-orbit coupling plays a crucial role in the optical spinpolarization and readout of NV quantum bit (qubit) and alike. Strong electron-phonon coupling in dynamic Jahn-Teller (DJT) systems can substantially influence the effective strength of spin-orbit coupling. Here we show by ab initio supercell density functional theory (DFT) calculations that the intrinsic spin-orbit coupling is strongly damped by DJT effect in the triplet excited state that has a consequence on the rate of non-radiative decay. This theory is applied to the ground state of silicon-vacancy (SiV) and germanium-vacancy (GeV) centers in their negatively charged state that can also act like qubits. We show that the intrinsic spin-orbit coupling in SiV and GeV centers is in the 100 GHz region, in contrast to the NV center of 10 GHz region. Our results provide deep insight in the nature of SiV and GeV qubits in diamond. EU FP7 DIADEMS project (Contract No. 611143).

The application of advanced PDC concepts proves effective in south Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahlem, J.S.; Baxter, R.L.; Dunn, K.E.

1996-12-01

Over the years, a variety of problems with polycrystalline diamond compact (PDC) bit design and application has been documented, with bit whirl being identified as the cause of many inherent problems. The goal of most PDC manufacturers, and the subject of this paper, is development of a better-performing, whirl-resistant PDC bit design. Similarly, the goal for most operators is the lower cost resulting from effective application of such bits. Toward those ends, a cooperative development effort between operators and a manufacturer was undertaken to apply advanced concepts effectively to the design, manufacture, and application of a new series of PDCmore » bits in south Texas. Adoption of design concepts, such as force-balanced cutting structures, asymmetric blade layouts, spiral blade designs, and tracking cutter arrangements, proved effective in countering the destructive effects of bit whirl, and allowed PDC bits to be used in harder formations. Summaries of both operational and economic performance confirm the success of the undertaking.« less

Low pressure growth of cubic boron nitride films

NASA Technical Reports Server (NTRS)

Ong, Tiong P. (Inventor); Shing, Yuh-Han (Inventor)

1997-01-01

A method for forming thin films of cubic boron nitride on substrates at low pressures and temperatures. A substrate is first coated with polycrystalline diamond to provide a uniform surface upon which cubic boron nitride can be deposited by chemical vapor deposition. The cubic boron nitride film is useful as a substitute for diamond coatings for a variety of applications in which diamond is not suitable. any tetragonal or hexagonal boron nitride. The cubic boron nitride produced in accordance with the preceding example is particularly well-suited for use as a coating for ultra hard tool bits and abrasives, especially those intended to use in cutting or otherwise fabricating iron.

Remote drill bit loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dokos, J.A.

1996-12-31

A drill bit loader is described for loading a tapered shank of a drill bit into a similarly tapered recess in the end of a drill spindle. The spindle has a transverse slot at the inner end of the recess. The end of the tapered shank of the drill bit has a transverse tang adapted to engage in the slot so that the drill bit will be rotated by the spindle. The loader is in the form of a cylinder adapted to receive the drill bit with the shank projecting out of the outer end of the cylinder. Retainer pinsmore » prevent rotation of the drill bit in the cylinder. The spindle is lowered to extend the shank of the drill bit into the recess in the spindle and the spindle is rotated to align the slot in the spindle with the tang on the shank. A spring unit in the cylinder is compressed by the drill bit during its entry into the recess of the spindle and resiliently drives the tang into the slot in the spindle when the tang and slot are aligned. In typical remote drilling operations, whether in hot cells or water pits, drill bits have been held using a collet or end mill type holder with set screws. In either case, to load or change a drill bit required the use master-slave manipulators to position the bits and tighten the collet or set screws. This requirement eliminated many otherwise useful work areas because they were not equipped with slaves, particularly in water pits.« less

Twinning of cubic diamond explains reported nanodiamond polymorphs

NASA Astrophysics Data System (ADS)

Németh, Péter; Garvie, Laurence A. J.; Buseck, Peter R.

2015-12-01

The unusual physical properties and formation conditions attributed to h-, i-, m-, and n-nanodiamond polymorphs has resulted in their receiving much attention in the materials and planetary science literature. Their identification is based on diffraction features that are absent in ordinary cubic (c-) diamond (space group: Fd-3m). We show, using ultra-high-resolution transmission electron microscope (HRTEM) images of natural and synthetic nanodiamonds, that the diffraction features attributed to the reported polymorphs are consistent with c-diamond containing abundant defects. Combinations of {113} reflection and <011> rotation twins produce HRTEM images and d-spacings that match those attributed to h-, i-, and m-diamond. The diagnostic features of n-diamond in TEM images can arise from thickness effects of c-diamonds. Our data and interpretations strongly suggest that the reported nanodiamond polymorphs are in fact twinned c-diamond. We also report a new type of twin (<11> rotational), which can give rise to grains with dodecagonal symmetry. Our results show that twins are widespread in diamond nanocrystals. A high density of twins could strongly influence their applications.

Antiwhirl PDC bits increased penetration rates in Alberta drilling. [Polycrystalline Diamond Compact

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bobrosky, D.; Osmak, G.

1993-07-05

The antiwhirl PDC bits and an inhibitive mud system contributed to the quicker drilling of the time-sensitive shales. The hole washouts in the intermediate section were dramatically reduced, resulting in better intermediate casing cement jobs. Also, the use of antirotation PDC-drillable cementing plugs eliminated the need to drill out plugs and float equipment with a steel tooth bit and then trip for the PDC bit. By using an antiwhirl PDC bit, at least one trip was eliminated in the intermediate section. Offset data indicated that two to six conventional bits would have been required to drill the intermediate hole interval.more » The PDC bit was rebuildable and therefore rerunnable even after being used on five wells. In each instance, the cost of replacing chipped cutters was less than the cost of a new insert roller cone bit. The paper describes the antiwhirl bits; the development of the bits; and their application in a clastic sequence, a carbonate sequence, and the Shekilie oil field; the improvement in the rate of penetration; the selection of bottom hole assemblies; washout problems; and drill-out characteristics.« less

Single Piezo-Actuator Rotary-Hammering Drill

NASA Technical Reports Server (NTRS)

Sherrit, Stewart; Bao, Xiaoqi; Badescu, Mircea; Bar-Cohen, Yoseph

2011-01-01

This innovation comprises a compact drill that uses low-axial preload, via vibrations, that fractures the rock under the bit kerf, and rotates the bit to remove the powdered cuttings while augmenting the rock fracture via shear forces. The vibrations fluidize the powered cuttings inside the flutes around the bit, reducing the friction with the auger surface. These combined actions reduce the consumed power and the heating of the drilled medium, helping to preserve the pristine content of the produced samples. The drill consists of an actuator that simultaneously impacts and rotates the bit by applying force and torque via a single piezoelectric stack actuator without the need for a gearbox or lever mechanism. This reduces the development/fabrication cost and complexity. The piezoelectric actuator impacts the surface and generates shear forces, fragmenting the drilled medium directly under the bit kerf by exceeding the tensile and/or shear strength of the struck surface. The percussive impact action of the actuator leads to penetration of the medium by producing a zone of finely crushed rock directly underneath the struck location. This fracturing process is highly enhanced by the shear forces from the rotation and twisting action. To remove the formed cuttings, the bit is constructed with an auger on its internal or external surface. One of the problems with pure hammering is that, as the teeth become embedded in the sample, the drilling efficiency drops unless the teeth are moved away from the specific footprint location. By rotating the teeth, they are moved to areas that were not fragmented, and thus the rock fracturing is enhanced via shear forces. The shear motion creates ripping or chiseling action to produce larger fragments to increase the drilling efficiency, and to reduce the required power. The actuator of the drill consists of a piezoelectric stack that vibrates the horn. The stack is compressed by a bolt between the backing and the horn in order to prevent it from being subjected to tensile stress that will cause it to fail. The backing is intended to transfer the generated mechanical vibrations towards the horn. In order to cause rotation, the horn is configured asymmetrically with helical segments and, upon impacting the bit, it introduces longitudinal along the axis of the actuator and tangential force causing twisting action that rotates the bit. The longitudinal component of the vibrations of the stack introduces percussion impulses between the bit and the rock to fracture it when the ultimate strain is exceeded under the bit.

Mathematical modeling of PDC bit drilling process based on a single-cutter mechanics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wojtanowicz, A.K.; Kuru, E.

1993-12-01

An analytical development of a new mechanistic drilling model for polycrystalline diamond compact (PDC) bits is presented. The derivation accounts for static balance of forces acting on a single PDC cutter and is based on assumed similarity between bit and cutter. The model is fully explicit with physical meanings given to all constants and functions. Three equations constitute the mathematical model: torque, drilling rate, and bit life. The equations comprise cutter`s geometry, rock properties drilling parameters, and four empirical constants. The constants are used to match the model to a PDC drilling process. Also presented are qualitative and predictive verificationsmore » of the model. Qualitative verification shows that the model`s response to drilling process variables is similar to the behavior of full-size PDC bits. However, accuracy of the model`s predictions of PDC bit performance is limited primarily by imprecision of bit-dull evaluation. The verification study is based upon the reported laboratory drilling and field drilling tests as well as field data collected by the authors.« less

Remote drill bit loader

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dokos, James A.

A drill bit loader for loading a tapered shank of a drill bit into a similarly tapered recess in the end of a drill spindle. The spindle has a transverse slot at the inner end of the recess. The end of the tapered shank of the drill bit has a transverse tang adapted to engage in the slot so that the drill bit will be rotated by the spindle. The loader is in the form of a cylinder adapted to receive the drill bit with the shank projecting out of the outer end of the cylinder. Retainer pins prevent rotationmore » of the drill bit in the cylinder. The spindle is lowered to extend the shank of the drill bit into the recess in the spindle and the spindle is rotated to align the slot in the spindle with the tang on the shank. A spring unit in the cylinder is compressed by the drill bit during its entry into the recess of the spindle and resiliently drives the tang into the slot in the spindle when the tang and slot are aligned.« less

A novel instrument for generating angular increments of 1 nanoradian

NASA Astrophysics Data System (ADS)

Alcock, Simon G.; Bugnar, Alex; Nistea, Ioana; Sawhney, Kawal; Scott, Stewart; Hillman, Michael; Grindrod, Jamie; Johnson, Iain

2015-12-01

Accurate generation of small angles is of vital importance for calibrating angle-based metrology instruments used in a broad spectrum of industries including mechatronics, nano-positioning, and optic fabrication. We present a novel, piezo-driven, flexure device capable of reliably generating micro- and nanoradian angles. Unlike many such instruments, Diamond Light Source's nano-angle generator (Diamond-NANGO) does not rely on two separate actuators or rotation stages to provide coarse and fine motion. Instead, a single Physik Instrumente NEXLINE "PiezoWalk" actuator provides millimetres of travel with nanometre resolution. A cartwheel flexure efficiently converts displacement from the linear actuator into rotary motion with minimal parasitic errors. Rotation of the flexure is directly measured via a Magnescale "Laserscale" angle encoder. Closed-loop operation of the PiezoWalk actuator, using high-speed feedback from the angle encoder, ensures that the Diamond-NANGO's output drifts by only ˜0.3 nrad rms over ˜30 min. We show that the Diamond-NANGO can reliably move with unprecedented 1 nrad (˜57 ndeg) angular increments over a range of >7000 μrad. An autocollimator, interferometer, and capacitive displacement sensor are used to independently confirm the Diamond-NANGO's performance by simultaneously measuring the rotation of a reflective cube.

A novel instrument for generating angular increments of 1 nanoradian.

PubMed

Alcock, Simon G; Bugnar, Alex; Nistea, Ioana; Sawhney, Kawal; Scott, Stewart; Hillman, Michael; Grindrod, Jamie; Johnson, Iain

2015-12-01

Accurate generation of small angles is of vital importance for calibrating angle-based metrology instruments used in a broad spectrum of industries including mechatronics, nano-positioning, and optic fabrication. We present a novel, piezo-driven, flexure device capable of reliably generating micro- and nanoradian angles. Unlike many such instruments, Diamond Light Source's nano-angle generator (Diamond-NANGO) does not rely on two separate actuators or rotation stages to provide coarse and fine motion. Instead, a single Physik Instrumente NEXLINE "PiezoWalk" actuator provides millimetres of travel with nanometre resolution. A cartwheel flexure efficiently converts displacement from the linear actuator into rotary motion with minimal parasitic errors. Rotation of the flexure is directly measured via a Magnescale "Laserscale" angle encoder. Closed-loop operation of the PiezoWalk actuator, using high-speed feedback from the angle encoder, ensures that the Diamond-NANGO's output drifts by only ∼0.3 nrad rms over ∼30 min. We show that the Diamond-NANGO can reliably move with unprecedented 1 nrad (∼57 ndeg) angular increments over a range of >7000 μrad. An autocollimator, interferometer, and capacitive displacement sensor are used to independently confirm the Diamond-NANGO's performance by simultaneously measuring the rotation of a reflective cube.

Diamond Machining of an Off-Axis Biconic Aspherical Mirror

NASA Technical Reports Server (NTRS)

Ohl, Raymond G.; Preuss, Werner; Sohn, Alex; MacKenty, John

2009-01-01

Two diamond-machining methods have been developed as part of an effort to design and fabricate an off-axis, biconic ellipsoidal, concave aluminum mirror for an infrared spectrometer at the Kitt Peak National Observatory. Beyond this initial application, the methods can be expected to enable satisfaction of requirements for future instrument mirrors having increasingly complex (including asymmetrical), precise shapes that, heretofore, could not readily be fabricated by diamond machining or, in some cases, could not be fabricated at all. In the initial application, the mirror is prescribed, in terms of Cartesian coordinates x and y, by aperture dimensions of 94 by 76 mm, placements of -2 mm off axis in x and 227 mm off axis in y, an x radius of curvature of 377 mm, a y radius of curvature of 407 mm, an x conic constant of 0.078, and a y conic constant of 0.127. The aspect ratio of the mirror blank is about 6. One common, "diamond machining" process uses single-point diamond turning (SPDT). However, it is impossible to generate the required off-axis, biconic ellipsoidal shape by conventional SPDT because (1) rotational symmetry is an essential element of conventional SPDT and (2) the present off-axis biconic mirror shape lacks rotational symmetry. Following conventional practice, it would be necessary to make this mirror from a glass blank by computer-controlled polishing, which costs more than diamond machining and yields a mirror that is more difficult to mount to a metal bench. One of the two present diamond machining methods involves the use of an SPDT machine equipped with a fast tool servo (FTS). The SPDT machine is programmed to follow the rotationally symmetric asphere that best fits the desired off-axis, biconic ellipsoidal surface. The FTS is actuated in synchronism with the rotation of the SPDT machine to generate the difference between the desired surface and the best-fit rotationally symmetric asphere. In order to minimize the required stroke of the FTS, the blanks were positioned at a large off-axis distance and angle, and the axis of the FTS was not parallel to the axis of the spindle of the SPDT machine. The spindle was rotated at a speed of 120 rpm, and the maximum FTS speed was 8.2 mm/s.

Numerical simulation study on the optimization design of the crown shape of PDC drill bit.

PubMed

Ju, Pei; Wang, Zhenquan; Zhai, Yinghu; Su, Dongyu; Zhang, Yunchi; Cao, Zhaohui

The design of bit crown is an important part of polycrystalline diamond compact (PDC) bit design, although predecessors have done a lot of researches on the design principles of PDC bit crown, the study of the law about rock-breaking energy consumption according to different bit crown shape is not very systematic, and the mathematical model of design is over-simplified. In order to analyze the relation between rock-breaking energy consumption and bit crown shape quantificationally, the paper puts forward an idea to take "per revolution-specific rock-breaking work" as objective function, and analyzes the relationship between rock properties, inner cone angle, outer cone arc radius, and per revolution-specific rock-breaking work by means of explicit dynamic finite element method. Results show that the change law between per revolution-specific rock-breaking work and the radius of gyration is similar for rocks with different properties, it is beneficial to decrease rock-breaking energy consumption by decreasing inner cone angle or outer cone arc radius. Of course, we should also consider hydraulic structure and processing technology in the optimization design of PDC bit crown.

Photonic Modulation Using Bi-Directional Diamond Shaped Ring Lasers at 1550 NM

DTIC Science & Technology

2007-04-01

modes for (a) 1% of the relaxation running oscillation frequency and (b) just below free running relaxation oscillation frequency ... List of Tables Table 1. Power requirements needed for a ring laser based flash architecture. Table 2. Achievable bits using 10 mW and

HIGH-POWER TURBODRILL AND DRILL BIT FOR DRILLING WITH COILED TUBING

DOE Office of Scientific and Technical Information (OSTI.GOV)

Robert Radtke; David Glowka; Man Mohan Rai

2008-03-31

Commercial introduction of Microhole Technology to the gas and oil drilling industry requires an effective downhole drive mechanism which operates efficiently at relatively high RPM and low bit weight for delivering efficient power to the special high RPM drill bit for ensuring both high penetration rate and long bit life. This project entails developing and testing a more efficient 2-7/8 in. diameter Turbodrill and a novel 4-1/8 in. diameter drill bit for drilling with coiled tubing. The high-power Turbodrill were developed to deliver efficient power, and the more durable drill bit employed high-temperature cutters that can more effectively drill hardmore » and abrasive rock. This project teams Schlumberger Smith Neyrfor and Smith Bits, and NASA AMES Research Center with Technology International, Inc (TII), to deliver a downhole, hydraulically-driven power unit, matched with a custom drill bit designed to drill 4-1/8 in. boreholes with a purpose-built coiled tubing rig. The U.S. Department of Energy National Energy Technology Laboratory has funded Technology International Inc. Houston, Texas to develop a higher power Turbodrill and drill bit for use in drilling with a coiled tubing unit. This project entails developing and testing an effective downhole drive mechanism and a novel drill bit for drilling 'microholes' with coiled tubing. The new higher power Turbodrill is shorter, delivers power more efficiently, operates at relatively high revolutions per minute, and requires low weight on bit. The more durable thermally stable diamond drill bit employs high-temperature TSP (thermally stable) diamond cutters that can more effectively drill hard and abrasive rock. Expectations are that widespread adoption of microhole technology could spawn a wave of 'infill development' drilling of wells spaced between existing wells, which could tap potentially billions of barrels of bypassed oil at shallow depths in mature producing areas. At the same time, microhole coiled tube drilling offers the opportunity to dramatically cut producers' exploration risk to a level comparable to that of drilling development wells. Together, such efforts hold great promise for economically recovering a sizeable portion of the estimated remaining shallow (less than 5,000 feet subsurface) oil resource in the United States. The DOE estimates this U.S. targeted shallow resource at 218 billion barrels. Furthermore, the smaller 'footprint' of the lightweight rigs utilized for microhole drilling and the accompanying reduced drilling waste disposal volumes offer the bonus of added environmental benefits. DOE analysis shows that microhole technology has the potential to cut exploratory drilling costs by at least a third and to slash development drilling costs in half.« less

Performance test of different 3.5 mm drill bits and consequences for orthopaedic surgery.

PubMed

Clement, Hans; Zopf, Christoph; Brandner, Markus; Tesch, Norbert P; Vallant, Rudolf; Puchwein, Paul

2015-12-01

Drilling of bones in orthopaedic and trauma surgery is a common procedure. There are yet no recommendations about which drill bits/coating should be preferred and when to change a used drill bit. In preliminary studies typical "drilling patterns" of surgeons concerning used spindle speed and feeding force were recorded. Different feeding forces were tested and abrasion was analysed using magnification and a scanning electron microscope (SEM). Acquired data were used for programming a friction stir welding machine (FSWM). Four drill bits (a default AISI 440A, a HSS, an AISI 440B and a Zirconium-oxide drill bit) were analysed for abrasive wear after 20/40/60 machine-guided and hand-driven drilled holes. Additionally different drill coatings [diamond-like carbon/grafitic (DLC), titanium nitride/carbide (Ti-N)] were tested. The mean applied feeding force by surgeons was 45 ± 15.6 Newton (N). HSS bits were still usable after 51 drill holes. Both coated AISI 440A bits showed considerable breakouts of the main cutting edge after 20 hand-driven drilled holes. The coated HSS bit showed very low abrasive wear. The non-coated AISI 440B bit had a similar durability to the HSS bits. The ZrO2 dental drill bit excelled its competitors (no considerable abrasive wear at >100 holes). If the default AISI 440A drill bit cannot be checked by 20-30× magnification after surgery, it should be replaced after 20 hand-driven drilled holes. Low price coated HSS bits could be a powerful alternative.

Numerical Prediction of the Influence of Process Parameters on Large Area Diamond Deposition by DC Arcjet with ARC Roots Rotating and Operating at Gas Recycling Mode

NASA Astrophysics Data System (ADS)

Lu, F. X.; Huang, T. B.; Tang, W. Z.; Song, J. H.; Tong, Y. M.

A computer model have been set up for simulation of the flow and temperature field, and the radial distribution of atomic hydrogen and active carbonaceous species over a large area substrate surface for a new type dc arc plasma torch with rotating arc roots and operating at gas recycling mode A gas recycling radio of 90% was assumed. In numerical calculation of plasma chemistry, the Thermal-Calc program and a powerful thermodynamic database were employed. Numerical calculations to the computer model were performed using boundary conditions close to the experimental setup for large area diamond films deposition. The results showed that the flow and temperature field over substrate surface of Φ60-100mm were smooth and uniform. Calculations were also made with plasma of the same geometry but no arc roots rotation. It was clearly demonstrated that the design of rotating arc roots was advantageous for high quality uniform deposition of large area diamond films. Theoretical predictions on growth rate and film quality as well as their radial uniformity, and the influence of process parameters on large area diamond deposition were discussed in detail based on the spatial distribution of atomic hydrogen and the carbonaceous species in the plasma over the substrate surface obtained from thermodynamic calculations of plasma chemistry, and were compared with experimental observations.

Experimental realization of universal geometric quantum gates with solid-state spins.

PubMed

Zu, C; Wang, W-B; He, L; Zhang, W-G; Dai, C-Y; Wang, F; Duan, L-M

2014-10-02

Experimental realization of a universal set of quantum logic gates is the central requirement for the implementation of a quantum computer. In an 'all-geometric' approach to quantum computation, the quantum gates are implemented using Berry phases and their non-Abelian extensions, holonomies, from geometric transformation of quantum states in the Hilbert space. Apart from its fundamental interest and rich mathematical structure, the geometric approach has some built-in noise-resilience features. On the experimental side, geometric phases and holonomies have been observed in thermal ensembles of liquid molecules using nuclear magnetic resonance; however, such systems are known to be non-scalable for the purposes of quantum computing. There are proposals to implement geometric quantum computation in scalable experimental platforms such as trapped ions, superconducting quantum bits and quantum dots, and a recent experiment has realized geometric single-bit gates in a superconducting system. Here we report the experimental realization of a universal set of geometric quantum gates using the solid-state spins of diamond nitrogen-vacancy centres. These diamond defects provide a scalable experimental platform with the potential for room-temperature quantum computing, which has attracted strong interest in recent years. Our experiment shows that all-geometric and potentially robust quantum computation can be realized with solid-state spin quantum bits, making use of recent advances in the coherent control of this system.

Detection and analysis of diamond fingerprinting feature and its application

NASA Astrophysics Data System (ADS)

Li, Xin; Huang, Guoliang; Li, Qiang; Chen, Shengyi

2011-01-01

Before becoming a jewelry diamonds need to be carved artistically with some special geometric features as the structure of the polyhedron. There are subtle differences in the structure of this polyhedron in each diamond. With the spatial frequency spectrum analysis of diamond surface structure, we can obtain the diamond fingerprint information which represents the "Diamond ID" and has good specificity. Based on the optical Fourier Transform spatial spectrum analysis, the fingerprinting identification of surface structure of diamond in spatial frequency domain was studied in this paper. We constructed both the completely coherent diamond fingerprinting detection system illuminated by laser and the partially coherent diamond fingerprinting detection system illuminated by led, and analyzed the effect of the coherence of light source to the diamond fingerprinting feature. We studied rotation invariance and translation invariance of the diamond fingerprinting and verified the feasibility of real-time and accurate identification of diamond fingerprint. With the profit of this work, we can provide customs, jewelers and consumers with a real-time and reliable diamonds identification instrument, which will curb diamond smuggling, theft and other crimes, and ensure the healthy development of the diamond industry.

[Material found on the cleaned diamond turbine drilling heads after injury cases].

PubMed

Dielert, E

1979-06-01

Grinding of the hard tissues of the teeth with diamond points and airotor led to bullet-like flying off of part of the instrument. The causes were investigated: Unsatisfactory fixation in the turbine head, deficient material in the rotating instrument, unnecessary notches in the shaft resulting in reduction of diameter, and finally the so far uncorrected radial vibration of the rotating instrument. All of these causes may result in plastic deformation or breakage of the points.

Acquisition and Retaining Granular Samples via a Rotating Coring Bit

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Badescu, Mircea; Sherrit, Stewart

2013-01-01

This device takes advantage of the centrifugal forces that are generated when a coring bit is rotated, and a granular sample is entered into the bit while it is spinning, making it adhere to the internal wall of the bit, where it compacts itself into the wall of the bit. The bit can be specially designed to increase the effectiveness of regolith capturing while turning and penetrating the subsurface. The bit teeth can be oriented such that they direct the regolith toward the bit axis during the rotation of the bit. The bit can be designed with an internal flute that directs the regolith upward inside the bit. The use of both the teeth and flute can be implemented in the same bit. The bit can also be designed with an internal spiral into which the various particles wedge. In another implementation, the bit can be designed to collect regolith primarily from a specific depth. For that implementation, the bit can be designed such that when turning one way, the teeth guide the regolith outward of the bit and when turning in the opposite direction, the teeth will guide the regolith inward into the bit internal section. This mechanism can be implemented with or without an internal flute. The device is based on the use of a spinning coring bit (hollow interior) as a means of retaining granular sample, and the acquisition is done by inserting the bit into the subsurface of a regolith, soil, or powder. To demonstrate the concept, a commercial drill and a coring bit were used. The bit was turned and inserted into the soil that was contained in a bucket. While spinning the bit (at speeds of 600 to 700 RPM), the drill was lifted and the soil was retained inside the bit. To prove this point, the drill was turned horizontally, and the acquired soil was still inside the bit. The basic theory behind the process of retaining unconsolidated mass that can be acquired by the centrifugal forces of the bit is determined by noting that in order to stay inside the interior of the bit, the frictional force must be greater than the weight of the sample. The bit can be designed with an internal sleeve to serve as a container for granular samples. This tube-shaped component can be extracted upon completion of the sampling, and the bottom can be capped by placing the bit onto a corklike component. Then, upon removal of the internal tube, the top section can be sealed. The novel features of this device are: center dot A mechanism of acquiring and retaining granular samples using a coring bit without a closed door. center dot An acquisition bit that has internal structure such as a waffle pattern for compartmentalizing or helical internal flute to propel the sample inside the bit and help in acquiring and retaining granular samples. center dot A bit with an internal spiral into which the various particles wedge. center dot A design that provides a method of testing frictional properties of the granular samples and potentially segregating particles based on size and density. A controlled acceleration or deceleration may be used to drop the least-frictional particles or to eventually shear the unconsolidated material near the bit center.

Anisotropies in the linear polarization of vacancy photoluminescence in diamond induced by crystal rotations and strong magnetic fields

NASA Astrophysics Data System (ADS)

Braukmann, D.; Popov, V. P.; Glaser, E. R.; Kennedy, T. A.; Bayer, M.; Debus, J.

2018-03-01

We study the linear polarization properties of the photoluminescence of ensembles of neutral and negatively charged nitrogen vacancies and neutral vacancies in diamond crystals as a function of their symmetry and their response to strong external magnetic fields. The linear polarization degree, which exceeds 10% at room temperature, and rotation of the polarization plane of their zero-phonon lines significantly depend on the crystal rotation around specific axes demonstrating anisotropic angular evolutions. The sign of the polarization plane rotation is changed periodically through the crystal rotation, which indicates a switching between electron excited states of orthogonal linear polarizations. At external magnetic fields of up to 10 T, the angular dependencies of the linear polarization degree experience a remarkable phase shift. Moreover, the rotation of the linear polarization plane increases linearly with rising magnetic field at 6 K and room temperature, for the negatively charged nitrogen vacancies, which is attributed to magneto-optical Faraday rotation.

Quality Improvement of Chrome-Diamond Coatings on Flowing Chrome Plating

NASA Astrophysics Data System (ADS)

Belyaev, V. N.; Koslyuk, A. Yu; Lobunets, A. V.; Andreyev, A. S.

2016-04-01

The research results of the process of flowing chrome plating of internal surfaces of long-length cylindrical articles with the usage of electrolyte with ultra-dispersed diamonds when continuous article rotation, while chromium-plating, are presented. During experiments the following varying technological parameters: electrolyte temperature and article frequency rotation were chosen, and experimental samples were obtained. Estimation of porosity, micro-hardness, thickness of chrome coatings and uniformity were performed as well as the precipitation structure by the method of scanning electron microscopy. The results showed that the use of ultra-dispersed diamonds and realization of the scheme with rotation of detail-cathode when flowing chromium-plating allows one to increase servicing characteristics of the coating due to the decrease of grains size of chrome coating and porosity, and due to the increase of micro-hardness, so confirming the efficiency of using the suggested scheme of coating application and the given type of ultra-dispersed fillers when chromium-plating.

Technics study on high accuracy crush dressing and sharpening of diamond grinding wheel

NASA Astrophysics Data System (ADS)

Jia, Yunhai; Lu, Xuejun; Li, Jiangang; Zhu, Lixin; Song, Yingjie

2011-05-01

Mechanical grinding of artificial diamond grinding wheel was traditional wheel dressing process. The rotate speed and infeed depth of tool wheel were main technics parameters. The suitable technics parameters of metals-bonded diamond grinding wheel and resin-bonded diamond grinding wheel high accuracy crush dressing were obtained by a mount of experiment in super-hard material wheel dressing grind machine and by analysis of grinding force. In the same time, the effect of machine sharpening and sprinkle granule sharpening was contrasted. These analyses and lots of experiments had extent instruction significance to artificial diamond grinding wheel accuracy crush dressing.

Computer Simulation To Assess The Feasibility Of Coring Magma

NASA Astrophysics Data System (ADS)

Su, J.; Eichelberger, J. C.

2017-12-01

Lava lakes on Kilauea Volcano, Hawaii have been successfully cored many times, often with nearly complete recovery and at temperatures exceeding 1100oC. Water exiting nozzles on the diamond core bit face quenches melt to glass just ahead of the advancing bit. The bit readily cuts a clean annulus and the core, fully quenched lava, passes smoothly into the core barrel. The core remains intact after recovery, even when there are comparable amounts of glass and crystals with different coefficients of thermal expansion. The unique resulting data reveal the rate and sequence of crystal growth in cooling basaltic lava and the continuous liquid line of descent as a function of temperature from basalt to rhyolite. Now that magma bodies, rather than lava pooled at the surface, have been penetrated by geothermal drilling, the question arises as to whether similar coring could be conducted at depth, providing fundamentally new insights into behavior of magma. This situation is considerably more complex because the coring would be conducted at depths exceeding 2 km and drilling fluid pressures of 20 MPa or more. Criteria that must be satisfied include: 1) melt is quenched ahead of the bit and the core itself must be quenched before it enters the barrel; 2) circulating drilling fluid must keep the temperature of the coring assembling cooled to within operational limits; 3) the drilling fluid column must nowhere exceed the local boiling point. A fluid flow simulation was conducted to estimate the process parameters necessary to maintain workable temperatures during the coring operation. SolidWorks Flow Simulation was used to estimate the effect of process parameters on the temperature distribution of the magma immediately surrounding the borehole and of drilling fluid within the bottom-hole assembly (BHA). A solid model of the BHA was created in SolidWorks to capture the flow behavior around the BHA components. Process parameters used in the model include the fluid properties and temperature of magma, coolant flow rate, rotation speed, and rate of penetration (ROP). The modeling results indicate that there are combinations of process parameters that will provide sufficient cooling to enable the desired coring process in magma.

Nanocrystalline diamond coatings for mechanical seals applications.

PubMed

Santos, J A; Neto, V F; Ruch, D; Grácio, J

2012-08-01

A mechanical seal is a type of seal used in rotating equipment, such as pumps and compressors. It consists of a mechanism that assists the connection of the rotating shaft to the housings of the equipments, preventing leakage or avoiding contamination. A common cause of failure of these devices is end face wear out, thus the use of a hard, smooth and wear resistant coating such as nanocrystalline diamond would be of great importance to improve their working performance and increase their lifetime. In this paper, different diamond coatings were deposited by the HFCVD process, using different deposition conditions. Additionally, the as-grown films were characterized for, quality, morphology and microstructure using scanning electron microscopy (SEM) and Raman spectroscopy. The topography and the roughness of the films were characterized by atomic force microscopy (AFM).

Single Piezo-Actuator Rotary-Hammering (SPaRH) Drill

NASA Technical Reports Server (NTRS)

Sherrit, Stewart; Domm, Lukas; Bao, Xiaoqi; Bar-Cohen, Yoseph; Chang, Zensheu; Badescu, Mircea

2012-01-01

The search for present or past life in the Universe is one of the most important objectives of NASA's exploration missions. Drills for subsurface sampling of rocks, ice and permafrost are an essential tool for astrobiology studies on other planets. Increasingly, it is recognized that drilling via a combination of rotation and hammering offers an efficient and effective rapid penetration mechanism. The rotation provides an intrinsic method for removal of cuttings from the borehole while the impact and shear forces aids in the fracturing of the penetrated medium. Conventional drills that use a single actuator are based on a complex mechanism with many parts and their use in future mission involves greater risk of failure and/or may require lubrication that can introduce contamination. In this paper, a compact drill is reported that uses a single piezoelectric actuator to produce hammering and rotation of the bit. A horn with asymmetric grooves was design to impart a longitudinal (hammering) and transverse force (rotation) to a keyed free mass. The drill requires low axial pre-load since the hammering-impacts fracture the rock under the bit kerf and rotate the bit to remove the powdered cuttings while augmenting the rock fracture via shear forces. The vibrations 'fluidize' the powdered cuttings inside the flutes reducing the friction with the auger surface. This action reduces the consumed power and heating of the drilled medium helping to preserve the pristine content of the acquired samples. The drill consists of an actuator that simultaneously impacts and rotates the bit by applying force and torque via a single piezoelectric stack actuator without the need for a gearbox or lever mechanism. This can reduce the development/fabrication cost and complexity. In this paper, the drill mechanism will be described and the test results will be reported and discussed.

Diamond as an Optical Materials

DTIC Science & Technology

1992-02-20

method, a rotating polishing plate of iron (of low carbon content) or nickel is held at an elevated temperature inside an environmental chamber...produced the highest polishing rate and nickel produced nearly as high a polishina rate. No polishing action was observed with molybdenum plates or with...Diamond Films," Diamond Optics III, A. Feldman and S. Holly, Editors, Proc. SPIE 1325, 240-252 (1990). (9] W.D. Partlow, R.E. Witkowski, and J.P. McHugh in

Long-term data storage in diamond.

PubMed

Dhomkar, Siddharth; Henshaw, Jacob; Jayakumar, Harishankar; Meriles, Carlos A

2016-10-01

The negatively charged nitrogen vacancy (NV - ) center in diamond is the focus of widespread attention for applications ranging from quantum information processing to nanoscale metrology. Although most work so far has focused on the NV - optical and spin properties, control of the charge state promises complementary opportunities. One intriguing possibility is the long-term storage of information, a notion we hereby introduce using NV-rich, type 1b diamond. As a proof of principle, we use multicolor optical microscopy to read, write, and reset arbitrary data sets with two-dimensional (2D) binary bit density comparable to present digital-video-disk (DVD) technology. Leveraging on the singular dynamics of NV - ionization, we encode information on different planes of the diamond crystal with no cross-talk, hence extending the storage capacity to three dimensions. Furthermore, we correlate the center's charge state and the nuclear spin polarization of the nitrogen host and show that the latter is robust to a cycle of NV - ionization and recharge. In combination with super-resolution microscopy techniques, these observations provide a route toward subdiffraction NV charge control, a regime where the storage capacity could exceed present technologies.

Foldable Instrumented Bits for Ultrasonic/Sonic Penetrators

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Badescu, Mircea; Iskenderian, Theodore; Sherrit, Stewart; Bao, Xiaoqi; Linderman, Randel

2010-01-01

Long tool bits are undergoing development that can be stowed compactly until used as rock- or ground-penetrating probes actuated by ultrasonic/sonic mechanisms. These bits are designed to be folded or rolled into compact form for transport to exploration sites, where they are to be connected to their ultrasonic/ sonic actuation mechanisms and unfolded or unrolled to their full lengths for penetrating ground or rock to relatively large depths. These bits can be designed to acquire rock or soil samples and/or to be equipped with sensors for measuring properties of rock or soil in situ. These bits can also be designed to be withdrawn from the ground, restowed, and transported for reuse at different exploration sites. Apparatuses based on the concept of a probe actuated by an ultrasonic/sonic mechanism have been described in numerous prior NASA Tech Briefs articles, the most recent and relevant being "Ultrasonic/ Sonic Impacting Penetrators" (NPO-41666) NASA Tech Briefs, Vol. 32, No. 4 (April 2008), page 58. All of those apparatuses are variations on the basic theme of the earliest ones, denoted ultrasonic/sonic drill corers (USDCs). To recapitulate: An apparatus of this type includes a lightweight, low-power, piezoelectrically driven actuator in which ultrasonic and sonic vibrations are generated and coupled to a tool bit. The combination of ultrasonic and sonic vibrations gives rise to a hammering action (and a resulting chiseling action at the tip of the tool bit) that is more effective for drilling than is the microhammering action of ultrasonic vibrations alone. The hammering and chiseling actions are so effective that the size of the axial force needed to make the tool bit advance into soil, rock, or another material of interest is much smaller than in ordinary twist drilling, ordinary hammering, or ordinary steady pushing. Examples of properties that could be measured by use of an instrumented tool bit include electrical conductivity, permittivity, magnetic field, magnetic permeability, temperature, and any other properties that can be measured by fiber-optic sensors. The problem of instrumenting a probe of this type is simplified, relative to the problem of attaching electrodes in a rotating drill bit, in two ways: (1) Unlike a rotating drill bit, a bit of this type does not have flutes, which would compound the problem of ensuring contact between sensors and the side wall of a hole; and (2) there is no need for slip rings for electrical contact between sensor electronic circuitry and external circuitry because, unlike a rotating drill, a tool bit of this type is not rotated continuously during operation. One design for a tool bit of the present type is a segmented bit with a segmented, hinged support structure (see figure). The bit and its ultrasonic/sonic actuator are supported by a slider/guiding fixture, and its displacement and preload are controlled by a motor. For deployment from the folded configuration, a spring-loaded mechanism rotates the lower segment about the hinges, causing the lower segment to become axially aligned with the upper segment. A latching mechanism then locks the segments of the bit and the corresponding segments of the slider/guiding fixture. Then the entire resulting assembly is maneuvered into position for drilling into the ground. Another design provides for a bit comprising multiple tubular segments with an inner alignment string, similar to a foldable tent pole comprising multiple tubular segments with an inner elastic cable connecting the two ends. At the beginning of deployment, all segments except the first (lowermost) one remain folded, and the ultrasonic/sonic actuator is clamped to the top of the lowermost segment and used to drive this segment into the ground. When the first segment has penetrated to a specified depth, the second segment is connected to the upper end of the first segment to form a longer rigid tubular bit and the actuator is moved to the upper end of the second segnt. The process as described thus far is repeated, adding segments until the desired depth of penetration has been attained. Yet other designs provide for bits in the form of bistable circular- or rectangular- cross-section tubes that can be stowed compactly like rolls of flat tape and become rigidified upon extension to full length, in a manner partly similar to that of a common steel tape measure. Albeit not marketed for use in tool bits, a bistable reeled composite product that transforms itself from a flat coil to a rigid tube of circular cross section when unrolled, is commercially available under the trade name RolaTube(TradeMark) and serves as a model for the further development of tool bits of this subtype.

Rotary steerable motor system for underground drilling

DOEpatents

Turner, William E.; Perry, Carl A.; Wassell, Mark E.; Barbely, Jason R.; Burgess, Daniel E.; Cobern, Martin E.

2010-07-27

A preferred embodiment of a system for rotating and guiding a drill bit in an underground bore includes a drilling motor and a drive shaft coupled to drilling motor so that drill bit can be rotated by the drilling motor. The system further includes a guidance module having an actuating arm movable between an extended position wherein the actuating arm can contact a surface of the bore and thereby exert a force on the housing of the guidance module, and a retracted position.

Rotary steerable motor system for underground drilling

DOEpatents

Turner, William E [Durham, CT; Perry, Carl A [Middletown, CT; Wassell, Mark E [Kingwood, TX; Barbely, Jason R [Middletown, CT; Burgess, Daniel E [Middletown, CT; Cobern, Martin E [Cheshire, CT

2008-06-24

A preferred embodiment of a system for rotating and guiding a drill bit in an underground bore includes a drilling motor and a drive shaft coupled to drilling motor so that drill bit can be rotated by the drilling motor. The system further includes a guidance module having an actuating arm movable between an extended position wherein the actuating arm can contact a surface of the bore and thereby exert a force on the housing of the guidance module, and a retracted position.

Metasurfaced Reverberation Chamber.

PubMed

Sun, Hengyi; Li, Zhuo; Gu, Changqing; Xu, Qian; Chen, Xinlei; Sun, Yunhe; Lu, Shengchen; Martin, Ferran

2018-01-25

The concept of metasurfaced reverberation chamber (RC) is introduced in this paper. It is shown that by coating the chamber wall with a rotating 1-bit random coding metasurface, it is possible to enlarge the test zone of the RC while maintaining the field uniformity as good as that in a traditional RC with mechanical stirrers. A 1-bit random coding diffusion metasurface is designed to obtain all-direction backscattering under normal incidence. Three specific cases are studied for comparisons, including a (traditional) mechanical stirrer RC, a mechanical stirrer RC with a fixed diffusion metasurface, and a RC with a rotating diffusion metasurface. Simulation results show that the compact rotating diffusion metasurface can act as a stirrer with good stirring efficiency. By using such rotating diffusion metasurface, the test region of the RC can be greatly extended.

Mars Science Laboratory Drill

NASA Technical Reports Server (NTRS)

Okon, Avi B.; Brown, Kyle M.; McGrath, Paul L.; Klein, Kerry J.; Cady, Ian W.; Lin, Justin Y.; Ramirez, Frank E.; Haberland, Matt

2012-01-01

This drill (see Figure 1) is the primary sample acquisition element of the Mars Science Laboratory (MSL) that collects powdered samples from various types of rock (from clays to massive basalts) at depths up to 50 mm below the surface. A rotary-percussive sample acquisition device was developed with an emphasis on toughness and robustness to handle the harsh environment on Mars. It is the first rover-based sample acquisition device to be flight-qualified (see Figure 2). This drill features an autonomous tool change-out on a mobile robot, and novel voice-coil-based percussion. The drill comprises seven subelements. Starting at the end of the drill, there is a bit assembly that cuts the rock and collects the sample. Supporting the bit is a subassembly comprising a chuck mechanism to engage and release the new and worn bits, respectively, and a spindle mechanism to rotate the bit. Just aft of that is a percussion mechanism, which generates hammer blows to break the rock and create the dynamic environment used to flow the powdered sample. These components are mounted to a translation mechanism, which provides linear motion and senses weight-on-bit with a force sensor. There is a passive-contact sensor/stabilizer mechanism that secures the drill fs position on the rock surface, and flex harness management hardware to provide the power and signals to the translating components. The drill housing serves as the primary structure of the turret, to which the additional tools and instruments are attached. The drill bit assembly (DBA) is a passive device that is rotated and hammered in order to cut rock (i.e. science targets) and collect the cuttings (powder) in a sample chamber until ready for transfer to the CHIMRA (Collection and Handling for Interior Martian Rock Analysis). The DBA consists of a 5/8-in. (.1.6- cm) commercial hammer drill bit whose shank has been turned down and machined with deep flutes designed for aggressive cutting removal. Surrounding the shank of the bit is a thick-walled maraging steel collection tube allowing the powdered sample to be augured up the hole into the sample chamber. For robustness, the wall thickness of the DBA was maximized while still ensuring effective sample collection. There are four recesses in the bit tube that are used to retain the fresh bits in their bit box. The rotating bit is supported by a back-to-back duplex bearing pair within a housing that is connected to the outer DBA housing by two titanium diaphragms. The only bearings on the drill in the sample flow are protected by a spring-energized seal, and an integrated shield that diverts the ingested powdered sample from the moving interface. The DBA diaphragms provide radial constraint of the rotating bit and form the sample chambers. Between the diaphragms there is a sample exit tube from which the sample is transferred to the CHIMRA. To ensure that the entire collected sample is retained, no matter the orientation of the drill with respect to gravity during sampling, the pass-through from the forward to the aft chamber resides opposite to the exit tube.

Quantum random bit generation using energy fluctuations in stimulated Raman scattering.

PubMed

Bustard, Philip J; England, Duncan G; Nunn, Josh; Moffatt, Doug; Spanner, Michael; Lausten, Rune; Sussman, Benjamin J

2013-12-02

Random number sequences are a critical resource in modern information processing systems, with applications in cryptography, numerical simulation, and data sampling. We introduce a quantum random number generator based on the measurement of pulse energy quantum fluctuations in Stokes light generated by spontaneously-initiated stimulated Raman scattering. Bright Stokes pulse energy fluctuations up to five times the mean energy are measured with fast photodiodes and converted to unbiased random binary strings. Since the pulse energy is a continuous variable, multiple bits can be extracted from a single measurement. Our approach can be generalized to a wide range of Raman active materials; here we demonstrate a prototype using the optical phonon line in bulk diamond.

Diamond machine tool face lapping machine

DOEpatents

Yetter, H.H.

1985-05-06

An apparatus for shaping, sharpening and polishing diamond-tipped single-point machine tools. The isolation of a rotating grinding wheel from its driving apparatus using an air bearing and causing the tool to be shaped, polished or sharpened to be moved across the surface of the grinding wheel so that it does not remain at one radius for more than a single rotation of the grinding wheel has been found to readily result in machine tools of a quality which can only be obtained by the most tedious and costly processing procedures, and previously unattainable by simple lapping techniques.

Geometry and material choices govern hard-rock drilling performance of PDC drag cutters.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wise, Jack LeRoy

2005-06-01

Sandia National Laboratories has partnered with industry on a multifaceted, baseline experimental study that supports the development of improved drag cutters for advanced drill bits. Different nonstandard cutter lots were produced and subjected to laboratory tests that evaluated the influence of selected design and processing parameters on cutter loads, wear, and durability pertinent to the penetration of hard rock with mechanical properties representative of formations encountered in geothermal or deep oil/gas drilling environments. The focus was on cutters incorporating ultrahard PDC (polycrystalline diamond compact) overlays (i.e., diamond tables) on tungsten-carbide substrates. Parameter variations included changes in cutter geometry, material composition,more » and processing conditions. Geometric variables were the diamond-table thickness, the cutting-edge profile, and the PDC/substrate interface configuration. Material and processing variables for the diamond table were, respectively, the diamond particle size and the sintering pressure applied during cutter fabrication. Complementary drop-impact, granite-log abrasion, linear cutting-force, and rotary-drilling tests examined the response of cutters from each lot. Substantial changes in behavior were observed from lot to lot, allowing the identification of features contributing major (factor of 10+) improvements in cutting performance for hard-rock applications. Recent field demonstrations highlight the advantages of employing enhanced cutter technology during challenging drilling operations.« less

Towards quantum networks of single spins: analysis of a quantum memory with an optical interface in diamond.

PubMed

Blok, M S; Kalb, N; Reiserer, A; Taminiau, T H; Hanson, R

2015-01-01

Single defect centers in diamond have emerged as a powerful platform for quantum optics experiments and quantum information processing tasks. Connecting spatially separated nodes via optical photons into a quantum network will enable distributed quantum computing and long-range quantum communication. Initial experiments on trapped atoms and ions as well as defects in diamond have demonstrated entanglement between two nodes over several meters. To realize multi-node networks, additional quantum bit systems that store quantum states while new entanglement links are established are highly desirable. Such memories allow for entanglement distillation, purification and quantum repeater protocols that extend the size, speed and distance of the network. However, to be effective, the memory must be robust against the entanglement generation protocol, which typically must be repeated many times. Here we evaluate the prospects of using carbon nuclear spins in diamond as quantum memories that are compatible with quantum networks based on single nitrogen vacancy (NV) defects in diamond. We present a theoretical framework to describe the dephasing of the nuclear spins under repeated generation of NV spin-photon entanglement and show that quantum states can be stored during hundreds of repetitions using typical experimental coupling parameters. This result demonstrates that nuclear spins with weak hyperfine couplings are promising quantum memories for quantum networks.

Percussive Augmenter of Rotary Drills (PARoD)

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Hasenoehrl, Jennifer; Bar-Cohen, Yoseph; Sherrit, Stewart; Bao, Xiaoqi; Chang, Zensheu; Ostlund, Patrick; Aldrich, Jack

2013-01-01

Increasingly, NASA exploration mission objectives include sample acquisition tasks for in-situ analysis or for potential sample return to Earth. To address the requirements for samplers that could be operated at the conditions of the various bodies in the solar system, a piezoelectric actuated percussive sampling device was developed that requires low preload (as low as 10 N) which is important for operation at low gravity. This device can be made as light as 400 g, can be operated using low average power, and can drill rocks as hard as basalt. Significant improvement of the penetration rate was achieved by augmenting the hammering action by rotation and use of a fluted bit to provide effective cuttings removal. Generally, hammering is effective in fracturing drilled media while rotation of fluted bits is effective in cuttings removal. To benefit from these two actions, a novel configuration of a percussive mechanism was developed to produce an augmenter of rotary drills. The device was called Percussive Augmenter of Rotary Drills (PARoD). A breadboard PARoD was developed with a 6.4 mm (0.25 in) diameter bit and was demonstrated to increase the drilling rate of rotation alone by 1.5 to over 10 times. The test results of this configuration were published in a previous publication. Further, a larger PARoD breadboard with a 50.8 mm (2.0 in) diameter bit was developed and tested. This paper presents the design, analysis and test results of the large diameter bit percussive augmenter.

Little bits of diamond: Optically detected magnetic resonance of nitrogen-vacancy centers

NASA Astrophysics Data System (ADS)

Zhang, Haimei; Belvin, Carina; Li, Wanyi; Wang, Jennifer; Wainwright, Julia; Berg, Robbie; Bridger, Joshua

2018-03-01

We give instructions for the construction and operation of a simple apparatus for performing optically detected magnetic resonance measurements on diamond samples containing high concentrations of nitrogen-vacancy (NV) centers. Each NV center has a spin degree of freedom that can be manipulated and monitored by a combination of visible and microwave radiation. We observe Zeeman shifts in the presence of small external magnetic fields and describe a simple method to optically measure magnetic field strengths with a spatial resolution of several microns. The activities described are suitable for use in an advanced undergraduate lab course, powerfully connecting core quantum concepts to cutting edge applications. An even simpler setup, appropriate for use in more introductory settings, is also presented.

Growth, characterization and device development in monocrystalline diamond films

NASA Astrophysics Data System (ADS)

Davis, R. F.; Glass, J. T.; Nemanich, R. J.; Bozeman, S. P.; Sowers, A. T.

1995-06-01

Experimental and theoretical studies concerned with interface interactions of diamond with Si, Ni, and Ni3Si substrates have been conducted. Oriented diamond films deposited on (100) Si were characterized by polar Raman, polar x-ray diffraction (XRD), and cross-sectional high resolution transmission electron microscopy (HRTEM). These sutides showed that the diamond(100)/Si(100) interface adopted the 3:2-match arrangement rather than a 45 deg rotation. Extended Hueckel tight-binding (EHTB) electronic structure calculations for a model system revealed that the interface interaction favors the 3:2-match arrangement. Growth on polycrystalline Ni3Si resulted in oriented diamond particles; under the same growth conditions, graphite was formed on the nickel substrate. Our EHTB electronic structure calculations showed that the (111) and (100) surfaces of Ni3Si have a strong preference for diamond nucleation over graphite nucleation, but this was not the case for the (111) and (100) surfaces of Ni.

Topical review: spins and mechanics in diamond

NASA Astrophysics Data System (ADS)

Lee, Donghun; Lee, Kenneth W.; Cady, Jeffrey V.; Ovartchaiyapong, Preeti; Bleszynski Jayich, Ania C.

2017-03-01

There has been rapidly growing interest in hybrid quantum devices involving a solid-state spin and a macroscopic mechanical oscillator. Such hybrid devices create exciting opportunities to mediate interactions between disparate quantum bits (qubits) and to explore the quantum regime of macroscopic mechanical objects. In particular, a system consisting of the nitrogen-vacancy defect center (NV center) in diamond coupled to a high-quality-factor mechanical oscillator is an appealing candidate for such a hybrid quantum device, as it utilizes the highly coherent and versatile spin properties of the defect center. In this paper, we will review recent experimental progress on diamond-based hybrid quantum devices in which the spin and orbital dynamics of single defects are driven by the motion of a mechanical oscillator. In addition, we discuss prospective applications for this device, including long-range, phonon-mediated spin-spin interactions, and phonon cooling in the quantum regime. We conclude the review by evaluating the experimental limitations of current devices and identifying alternative device architectures that may reach the strong coupling regime.

Complete Quantum Control of a Single Silicon-Vacancy Center in a Diamond Nanopillar

NASA Astrophysics Data System (ADS)

Zhang, Jingyuan Linda; Lagoudakis, Konstantinos G.; Tzeng, Yan-Kai; Dory, Constantin; Radulaski, Marina; Kelaita, Yousif; Shen, Zhi-Xun; Melosh, Nicholas A.; Chu, Steven; Vuckovic, Jelena

Coherent quantum control of a quantum bit (qubit) is an important step towards its use in a quantum network. SiV- center in diamond offers excellent physical qualities such as low inhomogeneous broadening, fast photon emission, and a large Debye-Waller factor, while the fast spin manipulation and techniques to extend the spin coherence time are under active investigation. Here, we demonstrate full coherent control over the state of a single SiV- center in a diamond nanopillar using ultrafast optical pulses. The high quality of the chemical vapor deposition grown SiV- centers allows us to coherently manipulate and quasi-resonantly read out the state of the single SiV- center. Moreover, the SiV- centers being coherently controlled are integrated into diamond nanopillar arrays in a site-controlled, individually addressable manner with high yield, low strain, and high spectral stability, which paves the way for scalable on chip optically accessible quantum system in a quantum photonic network. Financial support is provided by the DOE Office of Basic Energy Sciences, Division of Materials Sciences through Stanford Institute for Materials and Energy Sciences (SIMES) under contract DE-AC02-76SF00515.

Long-term data storage in diamond

PubMed Central

Dhomkar, Siddharth; Henshaw, Jacob; Jayakumar, Harishankar; Meriles, Carlos A.

2016-01-01

The negatively charged nitrogen vacancy (NV−) center in diamond is the focus of widespread attention for applications ranging from quantum information processing to nanoscale metrology. Although most work so far has focused on the NV− optical and spin properties, control of the charge state promises complementary opportunities. One intriguing possibility is the long-term storage of information, a notion we hereby introduce using NV-rich, type 1b diamond. As a proof of principle, we use multicolor optical microscopy to read, write, and reset arbitrary data sets with two-dimensional (2D) binary bit density comparable to present digital-video-disk (DVD) technology. Leveraging on the singular dynamics of NV− ionization, we encode information on different planes of the diamond crystal with no cross-talk, hence extending the storage capacity to three dimensions. Furthermore, we correlate the center’s charge state and the nuclear spin polarization of the nitrogen host and show that the latter is robust to a cycle of NV− ionization and recharge. In combination with super-resolution microscopy techniques, these observations provide a route toward subdiffraction NV charge control, a regime where the storage capacity could exceed present technologies. PMID:27819045

Counter-Rotating Tandem Motor Drilling System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kent Perry

2009-04-30

Gas Technology Institute (GTI), in partnership with Dennis Tool Company (DTC), has worked to develop an advanced drill bit system to be used with microhole drilling assemblies. One of the main objectives of this project was to utilize new and existing coiled tubing and slimhole drilling technologies to develop Microhole Technology (MHT) so as to make significant reductions in the cost of E&P down to 5000 feet in wellbores as small as 3.5 inches in diameter. This new technology was developed to work toward the DOE's goal of enabling domestic shallow oil and gas wells to be drilled inexpensively comparedmore » to wells drilled utilizing conventional drilling practices. Overall drilling costs can be lowered by drilling a well as quickly as possible. For this reason, a high drilling rate of penetration is always desired. In general, high drilling rates of penetration (ROP) can be achieved by increasing the weight on bit and increasing the rotary speed of the bit. As the weight on bit is increased, the cutting inserts penetrate deeper into the rock, resulting in a deeper depth of cut. As the depth of cut increases, the amount of torque required to turn the bit also increases. The Counter-Rotating Tandem Motor Drilling System (CRTMDS) was planned to achieve high rate of penetration (ROP) resulting in the reduction of the drilling cost. The system includes two counter-rotating cutter systems to reduce or eliminate the reactive torque the drillpipe or coiled tubing must resist. This would allow the application of maximum weight-on-bit and rotational velocities that a coiled tubing drilling unit is capable of delivering. Several variations of the CRTDMS were designed, manufactured and tested. The original tests failed leading to design modifications. Two versions of the modified system were tested and showed that the concept is both positive and practical; however, the tests showed that for the system to be robust and durable, borehole diameter should be substantially larger than that of slim holes. As a result, the research team decided to complete the project, document the tested designs and seek further support for the concept outside of the DOE.« less

PDC Bit Testing at Sandia Reveals Influence of Chatter in Hard-Rock Drilling

DOE Office of Scientific and Technical Information (OSTI.GOV)

RAYMOND,DAVID W.

1999-10-14

Polycrystalline diamond compact (PDC) bits have yet to be routinely applied to drilling the hard-rock formations characteristic of geothermal reservoirs. Most geothermal production wells are currently drilled with tungsten-carbide-insert roller-cone bits. PDC bits have significantly improved penetration rates and bit life beyond roller-cone bits in the oil and gas industry where soft to medium-hard rock types are encountered. If PDC bits could be used to double current penetration rates in hard rock geothermal well-drilling costs could be reduced by 15 percent or more. PDC bits exhibit reasonable life in hard-rock wear testing using the relatively rigid setups typical of laboratorymore » testing. Unfortunately, field experience indicates otherwise. The prevailing mode of failure encountered by PDC bits returning from hard-rock formations in the field is catastrophic, presumably due to impact loading. These failures usually occur in advance of any appreciable wear that might dictate cutter replacement. Self-induced bit vibration, or ''chatter'', is one of the mechanisms that may be responsible for impact damage to PDC cutters in hard-rock drilling. Chatter is more severe in hard-rock formations since they induce significant dynamic loading on the cutter elements. Chatter is a phenomenon whereby the drillstring becomes dynamically unstable and excessive sustained vibrations occur. Unlike forced vibration, the force (i.e., weight on bit) that drives self-induced vibration is coupled with the response it produces. Many of the chatter principles derived in the machine tool industry are applicable to drilling. It is a simple matter to make changes to a machine tool to study the chatter phenomenon. This is not the case with drilling. Chatter occurs in field drilling due to the flexibility of the drillstring. Hence, laboratory setups must be made compliant to observe chatter.« less

Percussive Augmenter of Rotary Drills (PARoD)

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Bar-Cohen, Yoseph; Sherrit, Stewart; Bao, Xiaoqi; Chang, Zensheu; Donnelly, Chris; Aldrich, Jack

2012-01-01

Increasingly, NASA exploration mission objectives include sample acquisition tasks for in-situ analysis or for potential sample return to Earth. To address the requirements for samplers that could be operated at the conditions of the various bodies in the solar system, a piezoelectric actuated percussive sampling device was developed that requires low preload (as low as 10N) which is important for operation at low gravity. This device can be made as light as 400g, can be operated using low average power, and can drill rocks as hard as basalt. Significant improvement of the penetration rate was achieved by augmenting the hammering action by rotation and use of a fluted bit to provide effective cuttings removal. Generally, hammering is effective in fracturing drilled media while rotation of fluted bits is effective in cuttings removal. To benefit from these two actions, a novel configuration of a percussive mechanism was developed to produce an augmenter of rotary drills. The device was called Percussive Augmenter of Rotary Drills (PARoD). A breadboard PARoD was developed with a 6.4 mm (0.25 in) diameter bit and was demonstrated to increase the drilling rate of rotation alone by 1.5 to over 10 times. Further, a large PARoD breadboard with 50.8 mm diameter bit was developed and its tests are currently underway. This paper presents the design, analysis and preliminary test results of the percussive augmenter.

Synchronizing Photography For High-Speed-Engine Research

NASA Technical Reports Server (NTRS)

Chun, K. S.

1989-01-01

Light flashes when shaft reaches predetermined angle. Synchronization system facilitates visualization of flow in high-speed internal-combustion engines. Designed for cinematography and holographic interferometry, system synchronizes camera and light source with predetermined rotational angle of engine shaft. 10-bit resolution of absolute optical shaft encoder adapted, and 2 to tenth power combinations of 10-bit binary data computed to corresponding angle values. Pre-computed angle values programmed into EPROM's (erasable programmable read-only memories) to use as angle lookup table. Resolves shaft angle to within 0.35 degree at rotational speeds up to 73,240 revolutions per minute.

Experimental Study on Longmaxi Shale Breaking Mechanism with Micro-PDC Bit

NASA Astrophysics Data System (ADS)

Wang, Teng; Xiao, Xiaohua; Zhu, Haiyan; Zhao, Jingying; Li, Yuheng; Lu, Ming

2017-10-01

China has abundant shale gas resource, but its geological conditions are complicated. This work sought to find the shale breaking mechanism with the polycrystalline diamond compact (PDC) bit when drilling the shale that is rich in stratification. Therefore, a laboratory-scale drilling device based on a drilling machine is developed. The influences of Longmaxi shale stratification on drilling parameters in the drilling process with micro-PDC bit are investigated. Six groups of drilling experiments with six inclination angles ( β = 0°, 15°, 30°, 45°, 60° and 90°), total thirty-six groups, are carried out. The weight on bit reaches the maximum value at β = 30° and reaches the minimum value at β = 0°. The biggest torque value is at β = 30°, and the smaller torque values are at β = 15°, β = 45° and β = 60°. When the inclination angle is between 30° and 60°, the shale fragmentation volume is larger. The inclination angle β = 0° is beneficial, and β = 15° and β = 60° are detrimental to controlling the drilling direction in the Longmaxi shale gas formation.

Concurrent error detecting codes for arithmetic processors

NASA Technical Reports Server (NTRS)

Lim, R. S.

1979-01-01

A method of concurrent error detection for arithmetic processors is described. Low-cost residue codes with check-length l and checkbase m = 2 to the l power - 1 are described for checking arithmetic operations of addition, subtraction, multiplication, division complement, shift, and rotate. Of the three number representations, the signed-magnitude representation is preferred for residue checking. Two methods of residue generation are described: the standard method of using modulo m adders and the method of using a self-testing residue tree. A simple single-bit parity-check code is described for checking the logical operations of XOR, OR, and AND, and also the arithmetic operations of complement, shift, and rotate. For checking complement, shift, and rotate, the single-bit parity-check code is simpler to implement than the residue codes.

Quantum information. Unconditional quantum teleportation between distant solid-state quantum bits.

PubMed

Pfaff, W; Hensen, B J; Bernien, H; van Dam, S B; Blok, M S; Taminiau, T H; Tiggelman, M J; Schouten, R N; Markham, M; Twitchen, D J; Hanson, R

2014-08-01

Realizing robust quantum information transfer between long-lived qubit registers is a key challenge for quantum information science and technology. Here we demonstrate unconditional teleportation of arbitrary quantum states between diamond spin qubits separated by 3 meters. We prepare the teleporter through photon-mediated heralded entanglement between two distant electron spins and subsequently encode the source qubit in a single nuclear spin. By realizing a fully deterministic Bell-state measurement combined with real-time feed-forward, quantum teleportation is achieved upon each attempt with an average state fidelity exceeding the classical limit. These results establish diamond spin qubits as a prime candidate for the realization of quantum networks for quantum communication and network-based quantum computing. Copyright © 2014, American Association for the Advancement of Science.

Comparison of silicon, nickel, and nickel silicide (Ni 3Si) as substrates for epitaxial diamond growth

NASA Astrophysics Data System (ADS)

Tucker, D. A.; Seo, D.-K.; Whangbo, M.-H.; Sivazlian, F. R.; Stoner, B. R.; Bozeman, S. P.; Sowers, A. T.; Nemanich, R. J.; Glass, J. T.

1995-07-01

We carried out experimental and theoretical studies aimed at probing interface interactions of diamond with Si, Ni, and Ni 3Si substrates. Oriented diamond films deposited on (100) silicon were characterized by polar Raman, polar XRD, and cross-sectional HRTEM. These studies show that the diamond-(100)/Si(100) interface does not adopt the 45°-rotation but the 3 : 2-match arrangement. Our extended Hückel tight-binding (EHTB) electronic structure calculations for a model system show that the interface interaction favors the 3 : 2-match arrangement. Growth on polycrystalline Ni 3Si resulted in oriented diamond particles while, under the same growth conditions, largely graphite was formed on the nickel substrate. Our EHTB electronic structure calculations for model systems show that the (111) and (100) surfaces of Ni 3Si have a strong preference for diamond-nucleation over graphite-nucleation, but this is not the case for the (111) and (100) surfaces of Ni.

The Pentagonal Principle for Self-Oriented Classes.

ERIC Educational Resources Information Center

Ball, Jerald T.

Under the pentagonal principle, a class is divided into groups of five (or six) to complete a discrete learning task, which is divided into five bits. Students take turns presenting the bits; if one fails, the group takes over. In this rotation, each student leads at least once in the session; the group verifies all steps. The instructor acts…

Experimental Primer on the Trapped Ion Quantum Computer

DTIC Science & Technology

1998-01-01

analogously), then exposing this ion to a traveling- wave electric field E�r� � E0 cos �k rÿ wLt � j� with frequency wL, phase j, and wavevector k, results...eih�a�a y��ij � Sjÿ eÿih�a�a y�ÿij� �4� in a frame rotating at wL, where terms oscillating faster than W j �Wj wz; w0� have been neglected. Here, h...of the single bit rotation gate and the two-bit controlled-NOT gate [34]. For brevity, we concentrate on these two gates and how they can be

Effects of drilling parameters in numerical simulation to the bone temperature elevation

NASA Astrophysics Data System (ADS)

Akhbar, Mohd Faizal Ali; Malik, Mukhtar; Yusoff, Ahmad Razlan

2018-04-01

Drilling into the bone can produce significant amount of heat which can cause bone necrosis. Understanding the drilling parameters influence to the heat generation is necessary to prevent thermal necrosis to the bone. The aim of this study is to investigate the influence of drilling parameters on bone temperature elevation. Drilling simulations of various combinations of drill bit diameter, rotational speed and feed rate were performed using finite element software DEFORM-3D. Full-factorial design of experiments (DOE) and two way analysis of variance (ANOVA) were utilised to examine the effect of drilling parameters and their interaction influence on the bone temperature. The maximum bone temperature elevation of 58% was demonstrated within the range in this study. Feed rate was found to be the main parameter to influence the bone temperature elevation during the drilling process followed by drill diameter and rotational speed. The interaction between drill bit diameter and feed rate was found to be significantly influence the bone temperature. It is discovered that the use of low rotational speed, small drill bit diameter and high feed rate are able to minimize the elevation of bone temperature for safer surgical operations.

Rotating Beam Fatigue Testing and Hybrid Ceramic Bearings.

DTIC Science & Technology

1994-07-01

Runout and Fast Fracture ......... 20 FIG.7 Stress-life Plots of Rotating Beam Fatigue Testing ............. 23 FIG.8 Fractograph of Rotating Beam...Chand-Kare Engineering Ceramics, Worcester, MA. Diamond wheels of 600 grits were used with longitudinal grinding applied for the final finishing of...stress in the range of 600-850 MPa. Three test completion modes were encountered, i.e. fast fracture at setup, fatigue fracture and runout (no failure

Extension and comparison of neoclassical models for poloidal rotation in tokamaks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stacey, W. M.

2008-01-15

Several neoclassical models for the calculation of poloidal rotation in tokamaks were rederived within a common framework, extended to include additional physics and numerically compared. The importance of new physics phenomena not usually included in poloidal rotation calculations (e.g., poloidal electric field, VxB force resulting from enhanced radial particle flow arising from the ionization of recycling neutrals) was examined. Extensions of the Hirshman-Sigmar, Kim-Diamond-Groebner, and Stacey-Sigmar poloidal rotation models are presented.

Rapid fabrication of miniature lens arrays by four-axis single point diamond machining

PubMed Central

McCall, Brian; Tkaczyk, Tomasz S.

2013-01-01

A novel method for fabricating lens arrays and other non-rotationally symmetric free-form optics is presented. This is a diamond machining technique using 4 controlled axes of motion – X, Y, Z, and C. As in 3-axis diamond micro-milling, a diamond ball endmill is mounted to the work spindle of a 4-axis ultra-precision computer numerical control (CNC) machine. Unlike 3-axis micro-milling, the C-axis is used to hold the cutting edge of the tool in contact with the lens surface for the entire cut. This allows the feed rates to be doubled compared to the current state of the art of micro-milling while producing an optically smooth surface with very low surface form error and exceptionally low radius error. PMID:23481813

Drilling plastic formations using highly polished PDC cutters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, R.H.; Lund, J.B.; Anderson, M.

1995-12-31

Highly plastic and over-pressured formations are troublesome for both roller cone and PDC bits. Thus far, attempts to increase penetration rates in these formations have centered around re-designing the bit or modifying the cutting structure. These efforts have produced only moderate improvements. This paper presents both laboratory and field data to illustrate the benefits of applying a mirror polished surface to the face of PDC cutters in drilling stressed formations. These cutters are similar to traditional PDC cutters, with the exception of the reflective mirror finish, applied to the diamond table surfaces prior to their installation in the bit. Resultsmore » of tests conducted in a single point cutter apparatus and a full-scale drilling simulator will be presented and discussed. Field results will be presented that demonstrate the effectiveness of polished cutters, in both water and oil-based muds. Increases in penetration rates of 300-400% have been observed in the Wilcox formation and other highly pressured shales. Typically, the beneficial effects of polished cutters have been realized at depths greater than 7000 ft, and with mud weights exceeding 12 ppg.« less

Error control techniques for satellite and space communications

NASA Technical Reports Server (NTRS)

Costello, Daniel J., Jr.

1991-01-01

Shannon's capacity bound shows that coding can achieve large reductions in the required signal to noise ratio per information bit (E sub b/N sub 0 where E sub b is the energy per bit and (N sub 0)/2 is the double sided noise density) in comparison to uncoded schemes. For bandwidth efficiencies of 2 bit/sym or greater, these improvements were obtained through the use of Trellis Coded Modulation and Block Coded Modulation. A method of obtaining these high efficiencies using multidimensional Multiple Phase Shift Keying (MPSK) and Quadrature Amplitude Modulation (QAM) signal sets with trellis coding is described. These schemes have advantages in decoding speed, phase transparency, and coding gain in comparison to other trellis coding schemes. Finally, a general parity check equation for rotationally invariant trellis codes is introduced from which non-linear codes for two dimensional MPSK and QAM signal sets are found. These codes are fully transparent to all rotations of the signal set.

Control mechanism of double-rotator-structure ternary optical computer

NASA Astrophysics Data System (ADS)

Kai, SONG; Liping, YAN

2017-03-01

Double-rotator-structure ternary optical processor (DRSTOP) has two characteristics, namely, giant data-bits parallel computing and reconfigurable processor, which can handle thousands of data bits in parallel, and can run much faster than computers and other optical computer systems so far. In order to put DRSTOP into practical application, this paper established a series of methods, namely, task classification method, data-bits allocation method, control information generation method, control information formatting and sending method, and decoded results obtaining method and so on. These methods form the control mechanism of DRSTOP. This control mechanism makes DRSTOP become an automated computing platform. Compared with the traditional calculation tools, DRSTOP computing platform can ease the contradiction between high energy consumption and big data computing due to greatly reducing the cost of communications and I/O. Finally, the paper designed a set of experiments for DRSTOP control mechanism to verify its feasibility and correctness. Experimental results showed that the control mechanism is correct, feasible and efficient.

Ultrasonic drilling apparatus

DOEpatents

Duran, Edward L.; Lundin, Ralph L.

1989-01-01

Apparatus attachable to an ultrasonic drilling machine for drilling deep holes in very hard materials, such as boron carbide, is provided. The apparatus utilizes a hollow spindle attached to the output horn of the ultrasonic drilling machine. The spindle has a hollow drill bit attached at the opposite end. A housing surrounds the spindle, forming a cavity for holding slurry. In operation, slurry is provided into the housing, and into the spindle through inlets while the spindle is rotating and ultrasonically reciprocating. Slurry flows through the spindle and through the hollow drill bit to cleanse the cutting edge of the bit during a drilling operation.

Ultrasonic drilling apparatus

DOEpatents

Duran, E.L.; Lundin, R.L.

1988-06-20

Apparatus attachable to an ultrasonic drilling machine for drilling deep holes in very hard materials, such as boron carbide, is provided. The apparatus utilizes a hollow spindle attached to the output horn of the ultrasonic drilling machine. The spindle has a hollow drill bit attached at the opposite end. A housing surrounds the spindle, forming a cavity for holding slurry. In operation, slurry is provided into the housing, and into the spindle through inlets while the spindle is rotating and ultrasonically reciprocating. Slurry flows through the spindle and through the hollow drill bit to cleanse the cutting edge of the bit during a drilling operation. 3 figs.

Lunar drill and test apparatus

NASA Technical Reports Server (NTRS)

Norrington, David W.; Ardoin, Didier C.; Alexander, Stephen G.; Rowland, Philip N.; Vastakis, Frank N.; Linsey, Steven L.

1988-01-01

The design of an experimental lunar drill and a facility to test the drill under simulated lunar conditions is described. The drill utilizes a polycrystalline diamond compact drag bit and an auger to mechanically remove cuttings from the hole. The drill will be tested in a vacuum chamber and powered through a vacuum seal by a drive mechanism located above the chamber. A general description of the design is provided followed by a detailed description and analysis of each component. Recommendations for the further development of the design are included.

Rhenium Alloys as Ductile Substrates for Diamond Thin-Film Electrodes.

PubMed

Halpern, Jeffrey M; Martin, Heidi B

2014-02-01

Molybdenum-rhenium (Mo/Re) and tungsten-rhenium (W/Re) alloys were investigated as substrates for thin-film, polycrystalline boron-doped diamond electrodes. Traditional, carbide-forming metal substrates adhere strongly to diamond but lose their ductility during exposure to the high-temperature (1000°C) diamond, chemical vapor deposition environment. Boron-doped semi-metallic diamond was selectively deposited for up to 20 hours on one end of Mo/Re (47.5/52.5 wt.%) and W/Re (75/25 wt.%) alloy wires. Conformal diamond films on the alloys displayed grain sizes and Raman signatures similar to films grown on tungsten; in all cases, the morphology and Raman spectra were consistent with well-faceted, microcrystalline diamond with minimal sp 2 carbon content. Cyclic voltammograms of dopamine in phosphate-buffered saline (PBS) showed the wide window and low baseline current of high-quality diamond electrodes. In addition, the films showed consistently well-defined, dopamine electrochemical redox activity. The Mo/Re substrate regions that were uncoated but still exposed to the diamond-growth environment remained substantially more flexible than tungsten in a bend-to-fracture rotation test, bending to the test maximum of 90° and not fracturing. The W/Re substrates fractured after a 27° bend, and the tungsten fractured after a 21° bend. Brittle, transgranular cleavage fracture surfaces were observed for tungsten and W/Re. A tension-induced fracture of the Mo/Re after the prior bend test showed a dimple fracture with a visible ductile core. Overall, the Mo/Re and W/Re alloys were suitable substrates for diamond growth. The Mo/Re alloy remained significantly more ductile than traditional tungsten substrates after diamond growth, and thus may be an attractive metal substrate for more ductile, thin-film diamond electrodes.

Rhenium Alloys as Ductile Substrates for Diamond Thin-Film Electrodes

PubMed Central

Halpern, Jeffrey M.; Martin, Heidi B.

2014-01-01

Molybdenum-rhenium (Mo/Re) and tungsten-rhenium (W/Re) alloys were investigated as substrates for thin-film, polycrystalline boron-doped diamond electrodes. Traditional, carbide-forming metal substrates adhere strongly to diamond but lose their ductility during exposure to the high-temperature (1000°C) diamond, chemical vapor deposition environment. Boron-doped semi-metallic diamond was selectively deposited for up to 20 hours on one end of Mo/Re (47.5/52.5 wt.%) and W/Re (75/25 wt.%) alloy wires. Conformal diamond films on the alloys displayed grain sizes and Raman signatures similar to films grown on tungsten; in all cases, the morphology and Raman spectra were consistent with well-faceted, microcrystalline diamond with minimal sp2 carbon content. Cyclic voltammograms of dopamine in phosphate-buffered saline (PBS) showed the wide window and low baseline current of high-quality diamond electrodes. In addition, the films showed consistently well-defined, dopamine electrochemical redox activity. The Mo/Re substrate regions that were uncoated but still exposed to the diamond-growth environment remained substantially more flexible than tungsten in a bend-to-fracture rotation test, bending to the test maximum of 90° and not fracturing. The W/Re substrates fractured after a 27° bend, and the tungsten fractured after a 21° bend. Brittle, transgranular cleavage fracture surfaces were observed for tungsten and W/Re. A tension-induced fracture of the Mo/Re after the prior bend test showed a dimple fracture with a visible ductile core. Overall, the Mo/Re and W/Re alloys were suitable substrates for diamond growth. The Mo/Re alloy remained significantly more ductile than traditional tungsten substrates after diamond growth, and thus may be an attractive metal substrate for more ductile, thin-film diamond electrodes. PMID:25404788

Double acting bit holder

DOEpatents

Morrell, Roger J.; Larson, David A.; Ruzzi, Peter L.

1994-01-01

A double acting bit holder that permits bits held in it to be resharpened during cutting action to increase energy efficiency by reducing the amount of small chips produced. The holder consist of: a stationary base portion capable of being fixed to a cutter head of an excavation machine and having an integral extension therefrom with a bore hole therethrough to accommodate a pin shaft; a movable portion coextensive with the base having a pin shaft integrally extending therefrom that is insertable in the bore hole of the base member to permit the moveable portion to rotate about the axis of the pin shaft; a recess in the movable portion of the holder to accommodate a shank of a bit; and a biased spring disposed in adjoining openings in the base and moveable portions of the holder to permit the moveable portion to pivot around the pin shaft during cutting action of a bit fixed in a turret to allow front, mid and back positions of the bit during cutting to lessen creation of small chip amounts and resharpen the bit during excavation use.

Factors Governing Surface Form Accuracy In Diamond Machined Components

NASA Astrophysics Data System (ADS)

Myler, J. K.; Page, D. A.

1988-10-01

Manufacturing methods for diamond machined optical surfaces, for application at infrared wavelengths, require that a new set of criteria must be recognised for the specification of surface form. Appropriate surface form parameters are discussed with particular reference to an XY cartesian geometry CNC machine. Methods for reducing surface form errors in diamond machining are discussed for certain areas such as tool wear, tool centring, and the fixturing of the workpiece. Examples of achievable surface form accuracy are presented. Traditionally, optical surfaces have been produced by use of random polishing techniques using polishing compounds and lapping tools. For lens manufacture, the simplest surface which could be created corresponded to a sphere. The sphere is a natural outcome of a random grinding and polishing process. The measurement of the surface form accuracy would most commonly be performed using a contact test gauge plate, polished to a sphere of known radius of curvature. QA would simply be achieved using a diffuse monochromatic source and looking for residual deviations between the polished surface and the test plate. The specifications governing the manufacture of surfaces using these techniques would call for the accuracy to which the generated surface should match the test plate as defined by a spherical deviations from the required curvature and a non spherical astigmatic error. Consequently, optical design software has tolerancing routines which specifically allow the designer to assess the influence of spherical error and astigmatic error on the optical performance. The creation of general aspheric surfaces is not so straightforward using conventional polishing techniques since the surface profile is non spherical and a good approximation to a power series. For infra red applications (X = 8-12p,m) numerically controlled single point diamond turning is an alternative manufacturing technology capable of creating aspheric profiles as well as simple spheres. It is important however to realise that a diamond turning process will possess a new set of criteria which limit the accuracy of the surface profile created corresponding to a completely new set of specifications. The most important factors are:- tool centring accuracy, surface waviness, conical form error, and other rotationally symmetric non spherical errors. The fixturing of the workpiece is very different from that of a conventional lap, since in many cases the diamond machine resembles a conventional lathe geometry where the workpiece rotates at a few thousand R.P.M. Substrates must be held rigidly for rotation at such speeds as compared with more delicate mounting methods for conventional laps. Consequently the workpiece may suffer from other forms of deformation which are non-rotationally symmetric due to mounting stresses (static deformation) and stresses induced at the speed of rotation (dynamic deformation). The magnitude of each of these contributions to overall form error will be a function of the type of machine, the material, substrate, and testing design. The following sections describe each of these effects in more detail based on experience obtained on a Pneumo Precision MSG325 XY CNC machine. Certain in-process measurement techniques have been devised to minimise and quantify each contribution.

Ultrasonic/Sonic Rotary-Hammer Drills

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Sherrit, Stewart; Bar-Cohen, Yoseph; Bao, Xiaoqi; Kassab, Steve

2010-01-01

Ultrasonic/sonic rotary-hammer drill (USRoHD) is a recent addition to the collection of apparatuses based on ultrasonic/sonic drill corer (USDC). As described below, the USRoHD has several features, not present in a basic USDC, that increase efficiency and provide some redundancy against partial failure. USDCs and related apparatuses were conceived for boring into, and/or acquiring samples of, rock or other hard, brittle materials of geological interest. They have been described in numerous previous NASA Tech Briefs articles. To recapitulate: A USDC can be characterized as a lightweight, lowpower, piezoelectrically driven jackhammer in which ultrasonic and sonic vibrations are generated and coupled to a tool bit. A basic USDC includes a piezoelectric stack, an ultrasonic transducer horn connected to the stack, a free mass ( free in the sense that it can bounce axially a short distance between hard stops on the horn and the bit), and a tool bit. The piezoelectric stack creates ultrasonic vibrations that are mechanically amplified by the horn. The bouncing of the free mass between the hard stops generates the sonic vibrations. The combination of ultrasonic and sonic vibrations gives rise to a hammering action (and a resulting chiseling action at the tip of the tool bit) that is more effective for drilling than is the microhammering action of ultrasonic vibrations alone. The hammering and chiseling actions are so effective that unlike in conventional twist drilling, little applied axial force is needed to make the apparatus advance into the material of interest. There are numerous potential applications for USDCs and related apparatuses in geological exploration on Earth and on remote planets. In early USDC experiments, it was observed that accumulation of cuttings in a drilled hole causes the rate of penetration of the USDC to decrease steeply with depth, and that the rate of penetration can be increased by removing the cuttings. The USRoHD concept provides for removal of cuttings in the same manner as that of a twist drill: An USRoHD includes a USDC and a motor with gearhead (see figure). The USDC provides the bit hammering and the motor provides the bit rotation. Like a twist drill bit, the shank of the tool bit of the USRoHD is fluted. As in the operation of a twist drill, the rotation of the fluted drill bit removes cuttings from the drilled hole. The USRoHD tool bit is tipped with a replaceable crown having cutting teeth on its front surface. The teeth are shaped to promote fracturing of the rock face through a combination of hammering and rotation of the tool bit. Helical channels on the outer cylindrical surface of the crown serve as a continuation of the fluted surface of the shank, helping to remove cuttings. In the event of a failure of the USDC, the USRoHD can continue to operate with reduced efficiency as a twist drill. Similarly, in the event of a failure of the gearmotor, the USRoHD can continue to operate with reduced efficiency as a USDC.

Aspects of ultra-high-precision diamond machining of RSA 443 optical aluminium

NASA Astrophysics Data System (ADS)

Mkoko, Z.; Abou-El-Hossein, K.

2015-08-01

Optical aluminium alloys such as 6061-T6 are traditionally used in ultra-high precision manufacturing for making optical mirrors for aerospace and other applications. However, the optics industry has recently witnessed the development of more advanced optical aluminium grades that are capable of addressing some of the issues encountered when turning with single-point natural monocrystalline diamond cutters. The advent of rapidly solidified aluminium (RSA) grades has generally opened up new possibilities for ultra-high precision manufacturing of optical components. In this study, experiments were conducted with single-point diamond cutters on rapidly solidified aluminium RSA 443 material. The objective of this study is to observe the effects of depth of cut and feed rate at a fixed rotational speed on the tool wear rate and resulting surface roughness of diamond turned specimens. This is done to gain further understanding of the rate of wear on the diamond cutters versus the surface texture generated on the RSA 443 material. The diamond machining experiments yielded machined surfaces which are less reflective but with consistent surface roughness values. Cutting tools were observed for wear through scanning microscopy; relatively low wear pattern was evident on the diamond tool edge. The highest tool wear were obtained at higher depth of cut and increased feed rate.

Moisture content of southern pine as related to thrust, torque, and chip formation in boring

Treesearch

Charles W. McMillin; George E. Woodson

1972-01-01

Holes 3-1/2 inches deep were bored with a 1-inch spur machine bit in southern pine having specific gravity of 0.53 (ovendry weight and volume at 10.4 percent moisture). The bit was rotated at 2,4000 rpm and removed chips 0.020 inch thick. For wood mositure contents ranging from ovendry to saturation, thrust was lower when boring along the grain (Average 98 pounds)...

Acousto-optical and SAW propagation characteristics of temperature stable multilayered structures based on LiNbO3 and diamond

NASA Astrophysics Data System (ADS)

Shandilya, Swati; Sreenivas, K.; Gupta, Vinay

2008-01-01

Theoretical studies on the surface acoustic wave (SAW) properties of c-axis oriented LiNbO3/IDT/diamond and diamond/IDT/128° rotated Y-X cut LiNbO3 multilayered structures have been considered. Both layered structures exhibit a positive temperature coefficient of delay (TCD) characteristic, and a zero TCD device is obtained after integrating with an over-layer of either tellurium dioxide (TeO2) or silicon dioxide (SiO2). The presence of a TeO2 over-layer enhanced the electromechanical coupling coefficients of both multilayered structures, which acts as a better temperature compensation layer than SiO2. The temperature stable TeO2/LiNbO3/IDT/diamond layered structure exhibits good electromechanical coefficient and higher phase velocity for SAW device applications. On the other hand, a high acousto-optical (AO) figure of merit (30-37) × 10-15 s3 kg-1 has been obtained for the temperature stable SiO2/diamond/IDT/LiNbO3 layered structure indicating a promising device structure for AO applications.

Realisation and robustness evaluation of a blind spatial domain watermarking technique

NASA Astrophysics Data System (ADS)

Parah, Shabir A.; Sheikh, Javaid A.; Assad, Umer I.; Bhat, Ghulam M.

2017-04-01

A blind digital image watermarking scheme based on spatial domain is presented and investigated in this paper. The watermark has been embedded in intermediate significant bit planes besides the least significant bit plane at the address locations determined by pseudorandom address vector (PAV). The watermark embedding using PAV makes it difficult for an adversary to locate the watermark and hence adds to security of the system. The scheme has been evaluated to ascertain the spatial locations that are robust to various image processing and geometric attacks JPEG compression, additive white Gaussian noise, salt and pepper noise, filtering and rotation. The experimental results obtained, reveal an interesting fact, that, for all the above mentioned attacks, other than rotation, higher the bit plane in which watermark is embedded more robust the system. Further, the perceptual quality of the watermarked images obtained in the proposed system has been compared with some state-of-art watermarking techniques. The proposed technique outperforms the techniques under comparison, even if compared with the worst case peak signal-to-noise ratio obtained in our scheme.

Endo-Fullerene and Doped Diamond Nanocrystallite Based Models of Qubits for Solid-State Quantum Computers

NASA Technical Reports Server (NTRS)

Park, Seongjun; Srivastava, Deepak; Cho, Kyeongjae; Biegel, Bryan (Technical Monitor)

2001-01-01

Models of encapsulated 1/2 nuclear spin H-1 and P-31 atoms in fullerene and diamond nanocrystallite, respectively, are proposed and examined with ab-initio local density functional method for possible applications as single quantum bits (qubits) in solid-state quantum computers. A H-1 atom encapsulated in a fully deuterated fullerene, C(sub 20)D(sub 20), forms the first model system and ab-initio calculation shows that H-1 atom is stable in atomic state at the center of the fullerene with a barrier of about 1 eV to escape. A P-31 atom positioned at the center of a diamond nanocrystallite is the second model system, and 3 1P atom is found to be stable at the substitutional site relative to interstitial sites by 15 eV, Vacancy formation energy is 6 eV in diamond so that substitutional P-31 atom will be stable against diffusion during the formation mechanisms within the nanocrystallite. The coupling between the nuclear spin and weakly bound (valance) donor electron coupling in both systems is found to be suitable for single qubit applications, where as the spatial distributions of (valance) donor electron wave functions are found to be preferentially spread along certain lattice directions facilitating two or more qubit applications. The feasibility of the fabrication pathways for both model solid-state qubit systems within practical quantum computers is discussed with in the context of our proposed solid-state qubits.

A Dynamic Pathway for Stone-Wales Bond Rotation on Carbon Nanotubes through Diamond-Like Bonds

NASA Technical Reports Server (NTRS)

Wei, Chen-Yu; Srivastava, Deepak; Cho, Kyeong-Jae; Menon, Madhu

2003-01-01

A new lower energy barrier with a two-step pathway of Stone-Wales (SW) ,ond rotation on carbon nanotubes (CNTs) is found through molecular dynamics (MD) simulations of CNTs under tension. The first step involves going over to a stable sp3-like metastable configuration with half rotated and partially tilted C-C bond. The second step involves going over to the fully rotated C-C bond with the formation of a SW defect in the nanotube. The energy barrier for this two-step dynamic pathway is significantly lower than the previously known static barrier for in-plane rotation of the C-C bond on a tensile strained (> 4%) CNT.

Moisture content of southern pine as related to thrust, torque, and chip formation in boring

Treesearch

C. W. McMillin; G. E. Woodson

1972-01-01

Holes 3-1/2 inches deep were bored with a 1-inch spur machine bit in southern pine having specific gravity of 0.53 (ovendry weight and volume at 10.4 percent moisture). The bit was rotated at 2,400 rpm and removed chips 0.020 inch thick. For wood moisture contents ranging from ovendry to saturation, thrust was lower when boring along the grain (average 98 pounds) than...

Deterministic switching of a magnetoelastic single-domain nano-ellipse using bending

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liang, Cheng-Yen; Sepulveda, Abdon; Keller, Scott

2016-03-21

In this paper, a fully coupled analytical model between elastodynamics with micromagnetics is used to study the switching energies using voltage induced mechanical bending of a magnetoelastic bit. The bit consists of a single domain magnetoelastic nano-ellipse deposited on a thin film piezoelectric thin film (500 nm) attached to a thick substrate (0.5 mm) with patterned electrodes underneath the nano-dot. A voltage applied to the electrodes produces out of plane deformation with bending moments induced in the magnetoelastic bit modifying the magnetic anisotropy. To minimize the energy, two design stages are used. In the first stage, the geometry and bias field (H{submore » b}) of the bit are optimized to minimize the strain energy required to rotate between two stable states. In the second stage, the bit's geometry is fixed, and the electrode position and control mechanism is optimized. The electrical energy input is about 200 (aJ) which is approximately two orders of magnitude lower than spin transfer torque approaches.« less

Mechanochemical induced structural changes in sucrose using the rotational diamond anvil cell

NASA Astrophysics Data System (ADS)

Ciezak-Jenkins, Jennifer A.; Jenkins, Timothy A.

2018-02-01

The response of sucrose to high-pressure and shear conditions has been studied in a rotational diamond anvil cell. Previous experiments conducted by Bridgman and Teller showed divergent behavior in regard to the existence of a rheological explosion under mechanochemical stimuli. Raman spectroscopy confirmed the existence of the isostructural Phase I to Phase II transition near 5 GPa. When subjected to high-pressure and shear, Raman spectra of Phase I showed evidence that while the sucrose molecule underwent significant molecular deformation, there was no evidence of a complete chemical reaction. In contrast, Phase II showed a near-total loss of the in-situ Raman signal in response to shear, suggesting the onset of amorphization or decomposition. The divergent behaviors of Phase I and Phase II are examined in light of the differences in the hydrogen bonding and plasticity of the material.

Pressure Self-focusing Effect and Novel Methods for Increasing the Maximum Pressure in Traditional and Rotational Diamond Anvil Cells.

PubMed

Feng, Biao; Levitas, Valery I

2017-04-21

The main principles of producing a region near the center of a sample, compressed in a diamond anvil cell (DAC), with a very high pressure gradient and, consequently, with high pressure are predicted theoretically. The revealed phenomenon of generating extremely high pressure gradient is called the pressure self-focusing effect. Initial analytical predictions utilized generalization of a simplified equilibrium equation. Then, the results are refined using our recent advanced model for elastoplastic material under high pressures in finite element method (FEM) simulations. The main points in producing the pressure self-focusing effect are to use beveled anvils and reach a very thin sample thickness at the center. We find that the superposition of torsion in a rotational DAC (RDAC) offers drastic enhancement of the pressure self-focusing effect and allows one to reach the same pressure under a much lower force and deformation of anvils.

A five-step procedure for the clinical use of the MPD in neuropsychological assessment of children.

PubMed

Wallbrown, F H; Fuller, G B

1984-01-01

Described a five-step procedure that can be used to detect organicity on the basis of children's performance on the Minnesota Percepto Diagnostic Test (MPD). The first step consists of examining the T score for rotations to determine whether it is below the cut-off score, which has been established empirically as an indicator of organicity. The second step consists of matching the examinee's configuration of error scores, separation of circle-diamond (SpCD), distortion of circle-diamond (DCD), and distortion of dots (DD), with empirically derived tables. The third step consists of considering the T score for rotations and error configuration jointly. The fourth step consists of using empirically established discriminant equations, and the fifth step involves using data from limits testing and other data sources. The clinical and empirical bases for the five-step procedure also are discussed.

Acoustically assisted spin-transfer-torque switching of nanomagnets: An energy-efficient hybrid writing scheme for non-volatile memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biswas, Ayan K.; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

We show that the energy dissipated to write bits in spin-transfer-torque random access memory can be reduced by an order of magnitude if a surface acoustic wave (SAW) is launched underneath the magneto-tunneling junctions (MTJs) storing the bits. The SAW-generated strain rotates the magnetization of every MTJs' soft magnet from the easy towards the hard axis, whereupon passage of a small spin-polarized current through a target MTJ selectively switches it to the desired state with > 99.99% probability at room temperature, thereby writing the bit. The other MTJs return to their original states at the completion of the SAW cycle.

Masks For Deposition Of Aspherical Optical Surfaces

NASA Technical Reports Server (NTRS)

Rogers, John R.; Martin, John D.

1992-01-01

Masks of improved design developed for use in fabrication of aspherical, rotationally symmetrical surfaces of mirrors, lenses, and lens molds by evaporative deposition onto rotating substrates. In deposition chamber, source and mask aligned with axis of rotation of substrate. Mask shadows source of rotating substrate. Azimuthal opening (as function of radius) in mask proportional to desired thickness (as function of radius) to which material deposited on substrate. Combination of improved masks and modern coating chambers provides optical surfaces comparable or superior to those produced by conventional polishing, computer-controlled polishing, replication from polished molds, and diamond turning, at less cost in material, labor, and capital expense.

A remote monitoring system for patients with implantable ventricular assist devices with a personal handy phone system.

PubMed

Okamoto, E; Shimanaka, M; Suzuki, S; Baba, K; Mitamura, Y

1999-01-01

The usefulness of a remote monitoring system that uses a personal handy phone for artificial heart implanted patients was investigated. The type of handy phone used in this study was a personal handy phone system (PHS), which is a system developed in Japan that uses the NTT (Nippon Telephone and Telegraph, Inc.) telephone network service. The PHS has several advantages: high-speed data transmission, low power output, little electromagnetic interference with medical devices, and easy locating of patients. In our system, patients have a mobile computer (Toshiba, Libretto 50, Kawasaki, Japan) for data transmission control between an implanted controller and a host computer (NEC, PC-9821V16) in the hospital. Information on the motor rotational angle (8 bits) and motor current (8 bits) of the implanted motor driven heart is fed into the mobile computer from the implanted controller (Hitachi, H8/532, Yokohama, Japan) according to 32-bit command codes from the host computer. Motor current and motor rotational angle data from inside the body are framed together by a control code (frame number and parity) for data error checking and correcting at the receiving site, and the data are sent through the PHS connection to the mobile computer. The host computer calculates pump outflow and arterial pressure from the motor rotational angle and motor current values and displays the data in real-time waveforms. The results of this study showed that accurate data on motor rotational angle and current could be transmitted from the subjects while they were walking or driving a car to the host computer at a data transmission rate of 9600 bps. This system is useful for remote monitoring of patients with an implanted artificial heart.

Shear Deformation of Fe Polycrystals in the Rotational Diamond Anvil Cell

NASA Astrophysics Data System (ADS)

Merkel, S.; Lincot, A.; Nisr, C.; Hanfland, M.; Zerr, A.

2014-12-01

For many years, experiments are being developed for performing deformation experiments under lower mantle conditions. They include methods such as the Deformation-DIA (Wang et al, 2003) or radial x-ray diffraction in the diamond anvil cell (Merkel et al, 2002). However, the strain applied to the sample is typically limited to about 40%. This can be an issue for studying effects of large deformation or, for the case of diamond anvil cells, applying actual plastic strain at megabar pressures. The issue can be solved using apparatus such as the Rotational-Drickamer (RDA) (e.g. Yamazaki and Karato, 2001). However, the RDA offers limited diffraction access to the sample and operating pressures do not reach those of the lower mantle.In this abstract, we investigate the potential applications of the rotational diamond anvil cell (Rot-DAC) for such studies. 300 K experiments in the Rot-DAC have been performed up to pressures exceeding 50 GPa (e.g. Serebryanaya et al, 1995) with studies focusing on the effect of shear on solid-solid phase transformation pressures. The authors did not investigate the possibility of using the Rot-DAC for studying rheological properties.Here, a sample of polycrystalline Fe is submitted to shear deformation in the Rot-DAC at pressures up to 20 GPa. Synchrotron X-ray diffraction and Rietveld refinements are then used to study the texture and stress state at multiple locations in the sample. The study shows that the Rot-DAC is efficient at producing deformation textures in a polycrystalline aggregate but that care should be taken in ensuring that the sample is actually undergoing plastic deformation and not solid rotation. Stresses, on the other hand, are difficult to extract from the x-ray diffraction data because of lack of understanding of stress distributions in the deforming aggregate.S. Merkel, H. R. Wenk, J. Shu, G. Shen, P. Gillet, H. K. Mao and R. J. Hemley, J. Geophys. Res., 107, 2271 (2002)N. Serebryanaya, V. Blank and V. Ivdenko, Phys. Lett. A, 197, 63-66 (1995)Y. Wang, W. B. Duhram, I. C. Getting and D. J. Weidner, Rev. Sci. Instrum., 74, 3002-3011 (2003)D. Yamazaki and S.-I. Karato, Rev. Sci. Instrum., 72, 4207-4211 (2001)

Mars Science Laboratory Drill

NASA Technical Reports Server (NTRS)

Okon, Avi B.

2010-01-01

The Drill for the Mars Science Laboratory mission is a rotary-percussive sample acquisition device with an emphasis on toughness and robustness to handle the harsh environment on Mars. The unique challenges associated with autonomous drilling from a mobile robot are addressed. A highly compressed development schedule dictated a modular design architecture that satisfies the functional and load requirements while allowing independent development and testing of the Drill subassemblies. The Drill consists of four actuated mechanisms: a spindle that rotates the bit, a chuck that releases and engages bits, a novel voice-coil-based percussion mechanism that hammers the bit, and a linear translation mechanism. The Drill has three passive mechanisms: a replaceable bit assembly that acquires and collects sample, a contact sensor / stabilizer mechanism, and, lastly a flex harness service loop. This paper describes the various mechanisms that makeup the Drill and discusses the solutions to their unique design and development challenges.

A decomposition approach to the design of a multiferroic memory bit

NASA Astrophysics Data System (ADS)

Acevedo, Ruben; Liang, Cheng-Yen; Carman, Gregory P.; Sepulveda, Abdon E.

2017-06-01

The objective of this paper is to present a methodology for the design of a memory bit to minimize the energy required to write data at the bit level. By straining a ferromagnetic nickel nano-dot by means of a piezoelectric substrate, its magnetization vector rotates between two stable states defined as a 1 and 0 for digital memory. The memory bit geometry, actuation mechanism and voltage control law were used as design variables. The approach used was to decompose the overall design process into simpler sub-problems whose structure can be exploited for a more efficient solution. This method minimizes the number of fully dynamic coupled finite element analyses required to converge to a near optimal design, thus decreasing the computational time for the design process. An in-plane sample design problem is presented to illustrate the advantages and flexibility of the procedure.

Trapezoidal diffraction grating beam splitters in single crystal diamond

NASA Astrophysics Data System (ADS)

Kiss, Marcell; Graziosi, Teodoro; Quack, Niels

2018-02-01

Single Crystal Diamond has been recognized as a prime material for optical components in high power applications due to low absorption and high thermal conductivity. However, diamond microstructuring remains challenging. Here, we report on the fabrication and characterization of optical diffraction gratings exhibiting a symmetric trapezoidal profile etched into a single crystal diamond substrate. The optimized grating geometry diffracts the transmitted optical power into precisely defined proportions, performing as an effective beam splitter. We fabricate our gratings in commercially available single crystal CVD diamond plates (2.6mm x 2.6mm x 0.3mm). Using a sputter deposited hard mask and patterning by contact lithography, the diamond is etched in an inductively coupled oxygen plasma with zero platen power. The etch process effectively reveals the characteristic {111} diamond crystal planes, creating a precisely defined angled (54.7°) profile. SEM and AFM measurements of the fabricated gratings evidence the trapezoidal shape with a pitch of 3.82μm, depth of 170 nm and duty cycle of 35.5%. Optical characterization is performed in transmission using a 650nm laser source perpendicular to the sample. The recorded transmitted optical power as function of detector rotation angle shows a distribution of 21.1% in the 0th order and 23.6% in each +/-1st order (16.1% reflected, 16.6% in higher orders). To our knowledge, this is the first demonstration of diffraction gratings with trapezoidal profile in single crystal diamond. The fabrication process will enable beam splitter gratings of custom defined optical power distribution profiles, while antireflection coatings can increase the efficiency.

Justification of the Shape of a Non-Circular Cross-Section for Drilling With a Roller Cutter

NASA Astrophysics Data System (ADS)

Buyalich, Gennady; Husnutdinov, Mikhail

2017-11-01

The parameters of the shape of non-circular cross-section affect not only the process of blasting, but also the design of the tool and the process of drilling as well. In the conditions of open-pit mining, it is reasonable to use a roller cutter to produce a non-circular cross-section of blasting holes. With regard to the roller cutter, the impact of the cross-section shape on the oscillations of the axial force arising upon its rotation is determined. It is determined that a polygonal shape with rounded comers of the borehole walls connections and their convex shape, which ensures a smaller range of the total axial force and the torque deflecting the bit from the axis of its rotation is the rational form of the non-circular cross-section of the borehole in terms of bit design. It has been shown that the ratio of the number of cutters to the number of borehole corners must be taken into account when justifying the shape of the cross-section, both from the point of view of the effectiveness of the explosion action and from the point of view of the rational design of the bit.

First-principles simulations of transition metal ions in silicon as potential quantum bits

NASA Astrophysics Data System (ADS)

Ma, He; Seo, Hosung; Galli, Giulia

Optically active spin defects in semiconductors have gained increasing attention in recent years for use as potential solid-state quantum bits (or qubits). Examples include the nitrogen-vacancy center in diamond, transition metal impurities, and rare earth ions. In this talk, we present first-principles theoretical results on group 6 transition metal ion (Chromium, Molybdenum and Tungsten) impurities in silicon, and we investigate their potential use as qubits. We used density functional theory (DFT) to calculate defect formation energies and we found that transition metal ions have lower formation energies at interstitial than substitutional sites. We also computed the electronic structure of the defects with particular attention to the position of the defect energy levels with respect to the silicon band edges. Based on our results, we will discuss the possibility of implementing qubits in silicon using group 6 transition metal ions. This work is supported by the National Science Foundation (NSF) through the University of Chicago MRSEC under Award Number DMR-1420709.

Surface micromachined counter-meshing gears discrimination device

DOEpatents

Polosky, Marc A.; Garcia, Ernest J.; Allen, James J.

2000-12-12

A surface micromachined Counter-Meshing Gears (CMG) discrimination device which functions as a mechanically coded lock. Each of two CMG has a first portion of its perimeter devoted to continuous driving teeth that mesh with respective pinion gears. Each EMG also has a second portion of its perimeter devoted to regularly spaced discrimination gear teeth that extend outwardly on at least one of three levels of the CMG. The discrimination gear teeth are designed so as to pass each other without interference only if the correct sequence of partial rotations of the CMG occurs in response to a coded series of rotations from the pinion gears. A 24 bit code is normally input to unlock the device. Once unlocked, the device provides a path for an energy or information signal to pass through the device. The device is designed to immediately lock up if any portion of the 24 bit code is incorrect.

Numerical analysis of micro-/nanoscale gas-film lubrication of sliding surface with complicated structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawagoe, Yoshiaki; Isono, Susumu; Takeno, Takanori

2014-12-09

It has been reported that the friction between a partially polished diamond-coated surface and a metal surface was drastically reduced to zero when they are slid at a few m/s. Since the sliding was noiseless, it seems that the diamond-coated surface was levitated over the counter surface and the sliding mechanism was the gas film lubrication. Recently, the mechanism of levitation of a slider with a micro/nanoscale surface structure on a rotating disk was theoretically clarified [S. Yonemura et al., Tribol. Lett., (2014), doi:10.1007/s11249-014-0368-2]. Probably, the partially polished diamond-coated surface may be levitated by high gas pressure generated by themore » micro/nanoscale surface structure on it. In this study, in order to verify our deduction, we performed numerical simulations of sliding of partially polished diamond-coated surface by reproducing its complicated surface structure using the data measured by an atomic force microscope (AFM). As a result, we obtained the lift force which is large enough to levitate the slider used in the experiment.« less

Testing New Techniques for Mars Rover Rock-Drilling

NASA Image and Video Library

2017-10-23

In the summer and fall of 2017, the team operating NASA's Curiosity Mars rover conducted tests in the "Mars Yard" at NASA's Jet Propulsion Laboratory, Pasadena, California, to develop techniques that Curiosity might be able to use to resume drilling into rocks on Mars. JPL robotics engineer Vladimir Arutyunov, in this June 29, 2017, photo, checks the test rover's drill bit at its contact point with a rock. Note that the stabilizer post visible to the right of the bit is not in contact with the rock, unlike the positioning used and photographed by Curiosity when drilling into rocks on Mars in 2013 to 2016. In late 2016, after Curiosity's drill had collected sample material from 15 Martian rocks, the drill's feed mechanism ceased working reliably. That motorized mechanism moved the bit forward or back with relation to the stabilizer posts on either side of the bit. In normal drilling by Curiosity, the stabilizers were positioned on the target rock first, and then the feed mechanism extended the rotation-percussion bit into the rock. In the alternative technique seen here, called "feed-extended drilling," the test rover's stabilizers are not used to touch the rock. The bit is advanced into the rock by motion of the robotic arm rather than the drill's feed mechanism. https://photojournal.jpl.nasa.gov/catalog/PIA22061

New Rock-Drilling Method in 'Mars Yard' Test

NASA Image and Video Library

2017-10-23

This photo taken in the "Mars Yard" at NASA's Jet Propulsion Laboratory, Pasadena, California, on Aug. 1, 2017, shows a step in development of possible alternative techniques that NASA's Curiosity Mars rover might be able to use to resume drilling into rocks on Mars. In late 2016, after Curiosity's drill had collected sample material from 15 Martian rocks in four years, the drill's feed mechanism ceased working reliably. That motorized mechanism moved the bit forward or back with relation to stabilizer posts on either side of the bit. In normal drilling by Curiosity, the stabilizers were positioned on the target rock first, and then the feed mechanism extended the rotation-percussion bit into the rock. In the alternative technique seen here, called "feed-extended drilling," the test rover's stabilizers are not used to touch the rock. The bit is advanced into the rock by motion of the robotic arm rather than the drill's feed mechanism. https://photojournal.jpl.nasa.gov/catalog/PIA22062

Study report on laser storage and retrieval of image data

NASA Technical Reports Server (NTRS)

Becker, C. H.

1976-01-01

The theoretical foundation is presented for a system of real-time nonphotographic and nonmagnetic digital laser storage and retrieval of image data. The system utilizes diffraction-limited laser focusing upon thin metal films, melting elementary holes in the metal films in laser focus. The metal films are encapsulated in rotating flexible mylar discs which act as the permanent storage carries. Equal sized holes encompass two dimensional digital ensembles of information bits which are time-sequentially (bit by bit) stored and retrieved. The bits possess the smallest possible size, defined by the Rayleigh criterion of coherent physical optics. Space and time invariant reflective read-out of laser discs with a small laser, provides access to the stored digital information. By eliminating photographic and magnetic data processing, which characterize the previous state of the art, photographic grain, diffusion, and gamma-distortion do not exist. Similarly, magnetic domain structures, magnetic gaps, and magnetic read-out are absent with a digital laser disc system.

Quantification of microscopic surface features of single point diamond turned optics with subsequent chemical polishing

NASA Astrophysics Data System (ADS)

Cardenas, Nelson; Kyrish, Matthew; Taylor, Daniel; Fraelich, Margaret; Lechuga, Oscar; Claytor, Richard; Claytor, Nelson

2015-03-01

Electro-Chemical Polishing is routinely used in the anodizing industry to achieve specular surface finishes of various metals products prior to anodizing. Electro-Chemical polishing functions by leveling the microscopic peaks and valleys of the substrate, thereby increasing specularity and reducing light scattering. The rate of attack is dependent of the physical characteristics (height, depth, and width) of the microscopic structures that constitute the surface finish. To prepare the sample, mechanical polishing such as buffing or grinding is typically required before etching. This type of mechanical polishing produces random microscopic structures at varying depths and widths, thus the electropolishing parameters are determined in an ad hoc basis. Alternatively, single point diamond turning offers excellent repeatability and highly specific control of substrate polishing parameters. While polishing, the diamond tool leaves behind an associated tool mark, which is related to the diamond tool geometry and machining parameters. Machine parameters such as tool cutting depth, speed and step over can be changed in situ, thus providing control of the spatial frequency of the microscopic structures characteristic of the surface topography of the substrate. By combining single point diamond turning with subsequent electro-chemical etching, ultra smooth polishing of both rotationally symmetric and free form mirrors and molds is possible. Additionally, machining parameters can be set to optimize post polishing for increased surface quality and reduced processing times. In this work, we present a study of substrate surface finish based on diamond turning tool mark spatial frequency with subsequent electro-chemical polishing.

Computers in the General Physics Laboratory.

ERIC Educational Resources Information Center

Preston, Daryl W.; Good, R. H.

1996-01-01

Provides ideas and outcomes for nine computer laboratory experiments using a commercial eight-bit analog to digital (ADC) interface. Experiments cover statistics; rotation; harmonic motion; voltage, current, and resistance; ADC conversions; temperature measurement; single slit diffraction; and radioactive decay. Includes necessary schematics. (MVL)

a Self-Excited System for Percussive-Rotary Drilling

NASA Astrophysics Data System (ADS)

Batako, A. D.; Babitsky, V. I.; Halliwell, N. A.

2003-01-01

A dynamic model for a new principle of percussive-rotary drilling is presented. This is a non-linear mechanical system with two degrees of freedom, in which friction-induced vibration is used for excitation of impacts, which influence the parameters of stick-slip motion. The model incorporates the friction force as a function of sliding velocity, which allows for the self-excitation of the coupled vibration of the rotating bit and striker, which tends to a steady state periodic cycle. The dynamic coupling of vibro-impact action with the stick-slip process provides an entirely new adaptive feature in the drilling process. The dynamic behaviour of the system with and without impact is studied numerically. Special attention is given to analysis of the relationship between the sticking and impacting phase of the process in order to achieve an optimal drilling performance. This paper provides an understanding of the mechanics of percussive -rotary drilling and design of new drilling tools with advanced characteristics. Conventional percussive-rotary drilling requires two independent actuators and special control for the synchronization of impact and rotation. In the approach presented, a combined complex interaction of drill bit and striker is synchronized by a single rotating drive.

Machining approach of freeform optics on infrared materials via ultra-precision turning.

PubMed

Li, Zexiao; Fang, Fengzhou; Chen, Jinjin; Zhang, Xiaodong

2017-02-06

Optical freeform surfaces are of great advantage in excellent optical performance and integrated alignment features. It has wide applications in illumination, imaging and non-imaging, etc. Machining freeform surfaces on infrared (IR) materials with ultra-precision finish is difficult due to its brittle nature. Fast tool servo (FTS) assisted diamond turning is a powerful technique for the realization of freeform optics on brittle materials due to its features of high spindle speed and high cutting speed. However it has difficulties with large slope angles and large rise-and-falls in the sagittal direction. In order to overcome this defect, the balance of the machining quality on the freeform surface and the brittle nature in IR materials should be realized. This paper presents the design of a near-rotational freeform surface (NRFS) with a low non-rotational degree (NRD) to constraint the variation of traditional freeform optics to solve this issue. In NRFS, the separation of the surface results in a rotational part and a residual part denoted as a non-rotational surface (NRS). Machining NRFS on germanium is operated by FTS diamond turning. Characteristics of the surface indicate that the optical finish of the freeform surface has been achieved. The modulation transfer function (MTF) of the freeform optics shows a good agreement to the design expectation. Images of the final optical system confirm that the fabricating strategy is of high efficiency and high quality. Challenges and prospects are discussed to provide guidance of future work.

Mars Rover Step Toward Possible Resumption of Drilling

NASA Image and Video Library

2017-10-23

NASA's Curiosity Mars rover conducted a test on Oct. 17, 2017, as part of the rover team's development of a new way to use the rover's drill. This image from Curiosity's front Hazard Avoidance Camera (Hazcam) shows the drill's bit touching the ground during an assessment of measurements by a sensor on the rover's robotic arm. Curiosity used its drill to acquire sample material from Martian rocks 15 times from 2013 to 2016. In December 2016, the drill's feed mechanism stopped working reliably. During the test shown in this image, the rover touched the drill bit to the ground for the first time in 10 months. The image has been adjusted to brighten shaded areas so that the bit is more evident. The date was the 1,848th Martian day, or sol, of Curiosity's work on Mars In drill use prior to December 2016, two contact posts -- the stabilizers on either side of the bit -- were placed on the target rock while the bit was in a withdrawn position. Then the motorized feed mechanism within the drill extended the bit forward, and the bit's rotation and percussion actions penetrated the rock. A promising alternative now under development and testing -- called feed-extended drilling -- uses motion of the robotic arm to directly advance the extended bit into a rock. In this image, the bit is touching the ground but the stabilizers are not. In the Sol 1848 activity, Curiosity pressed the drill bit downward, and then applied smaller sideways forces while taking measurements with a force/torque sensor on the arm. The objective was to gain understanding about how readings from the sensor can be used during drilling to adjust for any sideways pressure that might risk the bit becoming stuck in a rock. While rover-team engineers are working on an alternative drilling method, the mission continues to examine sites on Mount Sharp, Mars, with other tools. https://photojournal.jpl.nasa.gov/catalog/PIA22063

Electronic structure properties of deep defects in hBN

NASA Astrophysics Data System (ADS)

Dev, Pratibha; Prdm Collaboration

In recent years, the search for room-temperature solid-state qubit (quantum bit) candidates has revived interest in the study of deep-defect centers in semiconductors. The charged NV-center in diamond is the best known amongst these defects. However, as a host material, diamond poses several challenges and so, increasingly, there is an interest in exploring deep defects in alternative semiconductors such as hBN. The layered structure of hBN makes it a scalable platform for quantum applications, as there is a greater potential for controlling the location of the deep defect in the 2D-matrix through careful experiments. Using density functional theory-based methods, we have studied the electronic and structural properties of several deep defects in hBN. Native defects within hBN layers are shown to have high spin ground states that should survive even at room temperature, making them interesting solid-state qubit candidates in a 2D matrix. Partnership for Reduced Dimensional Material (PRDM) is part of the NSF sponsored Partnerships for Research and Education in Materials (PREM).

High-velocity frictional strength across the Tohoku-Oki megathrust determined from surface drilling torque

NASA Astrophysics Data System (ADS)

Ujiie, K.; Inoue, T.; Ishiwata, J.

2015-12-01

Frictional strength at seismic slip rates is a key to evaluate fault weakening and rupture propagation during earthquakes. The Japan Trench First Drilling Project (JFAST) drilled through the shallow plate-boundary thrust, where huge displacements of ~50 m occurred during the 2011 Tohoku-Oki earthquake. To determine the downhole frictional strength at drilled site (Site C0019), we analyzed surface drilling data. The equivalent slip rate estimated from the rotation rate and inner and outer radiuses of the drill bit ranges from 0.8 to 1.3 m/s. The measured torque includes the frictional torque between the drilling string and borehole wall, the viscous torque between the drilling string and seawater/drilling fluid, and the drilling torque between the drill bit and sediments. We subtracted the former two from the measured torque using the torque data during bottom-up rotating operations at several depths. Then, the shear stress was calculated from the drilling torque taking the configuration of the drill bit into consideration. The normal stress was estimated from the weight on bit data and the projected area of the drill bit. Assuming negligible cohesion, the frictional strength was obtained by dividing shear stress by normal stress. The results show a clear contrast in high-velocity frictional strength across the plate-boundary thrust: the friction coefficient of frontal prism sediments (hemipelagic mudstones) in hanging wall is 0.1-0.2, while that in subducting sediments (hemipelagic to pelagic mudstones and chert) in footwall increases to 0.2-0.4. The friction coefficient of smectite-rich pelagic clay in the plate-boundary thrust is ~0.1, which is consistent with that obtained from high-velocity (1.3 m/s) friction experiments and temperature measurements. We conclude that surface drilling torque provides useful data to obtain a continuous downhole frictional strength.

Dissipation Assisted Quantum Memory with Coupled Spin Systems

NASA Astrophysics Data System (ADS)

Jiang, Liang; Verstraete, Frank; Cirac, Ignacio; Lukin, Mikhail

2009-05-01

Dissipative dynamics often destroys quantum coherences. However, one can use dissipation to suppress decoherence. A well-known example is the so-called quantum Zeno effect, in which one can freeze the evolution using dissipative processes (e.g., frequently projecting the system to its initial state). Similarly, the undesired decoherence of quantum bits can also be suppressed using controlled dissipation. We propose and analyze the use of this generalization of quantum Zeno effect for protecting the quantum information encoded in the coupled spin systems. This new approach may potentially enhance the performance of quantum memories, in systems such as nitrogen-vacancy color-centers in diamond.

Quantum logic gates based on coherent electron transport in quantum wires.

PubMed

Bertoni, A; Bordone, P; Brunetti, R; Jacoboni, C; Reggiani, S

2000-06-19

It is shown that the universal set of quantum logic gates can be realized using solid-state quantum bits based on coherent electron transport in quantum wires. The elementary quantum bits are realized with a proper design of two quantum wires coupled through a potential barrier. Numerical simulations show that (a) a proper design of the coupling barrier allows one to realize any one-qbit rotation and (b) Coulomb interaction between two qbits of this kind allows the implementation of the CNOT gate. These systems are based on a mature technology and seem to be integrable with conventional electronics.

Drilled shaft resistance based on diameter, torque and crowd (drilling resistance vs. Rock strength) phase II : final report.

DOT National Transportation Integrated Search

2016-06-01

The research focused on evaluation of Florida limestones unconfined compressive strength, qu, through : drilling parameters crowd, torque, penetration rate, rotational speed, and bit diameter in both the : laboratory and field for assessin...

Video Clip of a Rover Rock-Drilling Demonstration at JPL

NASA Image and Video Library

2013-02-20

This frame from a video clip shows moments during a demonstration of drilling into a rock at NASA JPL, Pasadena, Calif., with a test double of the Mars rover Curiosity. The drill combines hammering and rotation motions of the bit.

Fabrication of an infrared Shack-Hartmann sensor by combining high-speed single-point diamond milling and precision compression molding processes.

PubMed

Zhang, Lin; Zhou, Wenchen; Naples, Neil J; Yi, Allen Y

2018-05-01

A novel fabrication method by combining high-speed single-point diamond milling and precision compression molding processes for fabrication of discontinuous freeform microlens arrays was proposed. Compared with slow tool servo diamond broaching, high-speed single-point diamond milling was selected for its flexibility in the fabrication of true 3D optical surfaces with discontinuous features. The advantage of single-point diamond milling is that the surface features can be constructed sequentially by spacing the axes of a virtual spindle at arbitrary positions based on the combination of rotational and translational motions of both the high-speed spindle and linear slides. By employing this method, each micro-lenslet was regarded as a microstructure cell by passing the axis of the virtual spindle through the vertex of each cell. An optimization arithmetic based on minimum-area fabrication was introduced to the machining process to further increase the machining efficiency. After the mold insert was machined, it was employed to replicate the microlens array onto chalcogenide glass. In the ensuing optical measurement, the self-built Shack-Hartmann wavefront sensor was proven to be accurate in detecting an infrared wavefront by both experiments and numerical simulation. The combined results showed that precision compression molding of chalcogenide glasses could be an economic and precision optical fabrication technology for high-volume production of infrared optics.

Noncontact on-machine measurement system based on capacitive displacement sensors for single-point diamond turning

NASA Astrophysics Data System (ADS)

Li, Xingchang; Zhang, Zhiyu; Hu, Haifei; Li, Yingjie; Xiong, Ling; Zhang, Xuejun; Yan, Jiwang

2018-04-01

On-machine measurements can improve the form accuracy of optical surfaces in single-point diamond turning applications; however, commercially available linear variable differential transformer sensors are inaccurate and can potentially scratch the surface. We present an on-machine measurement system based on capacitive displacement sensors for high-precision optical surfaces. In the proposed system, a position-trigger method of measurement was developed to ensure strict correspondence between the measurement points and the measurement data with no intervening time-delay. In addition, a double-sensor measurement was proposed to reduce the electric signal noise during spindle rotation. Using the proposed system, the repeatability of 80-nm peak-to-valley (PV) and 8-nm root-mean-square (RMS) was achieved through analyzing four successive measurement results. The accuracy of 109-nm PV and 14-nm RMS was obtained by comparing with the interferometer measurement result. An aluminum spherical mirror with a diameter of 300 mm was fabricated, and the resulting measured form error after one compensation cut was decreased to 254 nm in PV and 52 nm in RMS. These results confirm that the measurements of the surface form errors were successfully used to modify the cutting tool path during the compensation cut, thereby ensuring that the diamond turning process was more deterministic. In addition, the results show that the noise level was significantly reduced with the reference sensor even under a high rotational speed.

Drilling technique for crystals

NASA Technical Reports Server (NTRS)

Hunter, T.; Miyagawa, I.

1977-01-01

Hole-drilling technique uses special crystal driller in which drill bit rotates at fixed position at speed of 30 rpm while crystal slowly advances toward drill. Technique has been successfully applied to crystal of Rochell salt, Triglycine sulfate, and N-acetyglycine. Technique limits heat buildup and reduces strain on crystal.

Performance of current-in-plane pseudo-spin-valve devices on CMOS silicon-on-insulator underlayers

NASA Astrophysics Data System (ADS)

Katti, R. R.; Zou, D.; Reed, D.; Schipper, D.; Hynes, O.; Shaw, G.; Kaakani, H.

2003-05-01

Prior work has shown that current-in-plane (CIP) giant magnetoresistive (GMR) pseudo-spin-valve (PSV) devices grown on bulk Si wafers and bulk complementary metal-oxide semiconductor (CMOS) underlayers exhibit write and read characteristics that are suitable for application as nonvolatile memory devices. In this work, CIP GMR PSV devices fabricated on silicon-on-insulator CMOS underlayers are shown to support write and read performance. Reading and writing fields for selected devices are shown to be approximately 25%-50% that of unselected devices, which provides a margin for reading and writing specific bits in a memory without overwriting bits and without disturbing other bits. The switching characteristics of experimental devices were compared to and found to be similar with Landau-Lifschitz-Gilbert micromagnetic modeling results, which allowed inferring regions of reversible and irreversible rotations in magnetic reversal processes.

D.C. Arcjet Diamond Deposition

NASA Astrophysics Data System (ADS)

Russell, Derrek Andrew

1995-01-01

Polycrystalline diamond films synthesized by a D.C. (direct current) arcjet device was reported for the first time in 1988. This device is capable of higher diamond growth rates than any other form of diamond CVD (chemical vapor deposition) process due to its inherent versatility with regard to the enthalpy and fluid properties of the diamond-depositing vapor. Unfortunately, the versatility of this type of device is contrasted by many difficulties such as arc stability and large heat fluxes which make applying it toward diamond deposition a difficult problem. The purpose of this work was to convert the dc arcjet, which is primarily a metallurgical device, into a commercially viable diamond CVD process. The project was divided into two parts: process development and diagnostics. The process development effort concentrated on the certain engineering challenges. Among these was a novel arcjet design that allowed the carbon-source gas to be injected downstream of the tungsten cathode while still facilitating mixture with the main gas feed. Another engineering accomplishment was the incorporation of a water -cooled substrate cooler/spinner that maintained the substrate at the proper temperature, provided the substrate with a large thermal time constant to reduce thermal shock of the diamond film, and enabled the system to achieve a four -inch diameter growth area. The process diagnostics effort concentrated on measurements aimed at developing a fundamental understanding of the properties of the plasma jet such as temperature, plasma density, Mach number, pressure at the substrate, etc. The plasma temperature was determined to be 5195 K by measuring the rotational temperature of C _2 via optical emission spectroscopy. The Mach number of the plasma jet was determined to be ~6.0 as determined by the ratio of the stagnation pressures before and after the shock wave in the plasma jet. The C_2 concentration in the plasma jet was determined to be {~10 }^{12} cm^ {-3} by counting the number of radiated Swan band photons. This is big enough to account for a significant amount (10%) of the diamond growth.

A diamond in the sky: an exclusion or normal situation?

NASA Astrophysics Data System (ADS)

Kochemasov, G. G.

2009-04-01

A diamond in the sky: an exclusion or normal situation? G. Kochemasov IGEM of the Russian Academy of Sciences, Moscow, Russia, kochem.36@mail.ru The September 2008 observation and imaging by the ESA-"Rosetta" spacecraft of the small asteroid (2867) Steins should have a rather deep impact at planetological thinking. The planetology community is accustomed to think that the only process making forms of small bodies is the impact (accretion) process. No other forces are considered as though there is none. But actually there is one mighty process - a wave process that affects all cosmic bodies by warping them in several (normally four) directions. An origin of these warping waves is quite simple. All cosmic bodies move (orbit) and rotate. After I. Kepler we know that all orbits are non-round but elliptical (time rounds them but ellipticity always remain), and this means that orbiting bodies periodically cyclically change their accelerations (speeding up and slowing down). Multiplied by masses these changes produce forces applied to the bodies and causing oscillations of their spheres. In rotating bodies (but all bodies rotate!) these oscillations are decomposed (split) into four orthogonal and diagonal directions. Interfering of these directions produces uplifting, subsiding and neutral tectonic blocks which are observed on any celestial body more or less clearly. The blocks dimensions depend on lengths of warping waves that acquire a stationary character in closed spheres. That is why celestial spheres are not like billiards-balls but consist of regularly placed depressions (lowlands) and highlands. The longest fundamental wave 1 produces ubiquitous tectonic dichotomy - an opposition of subsided and bulged hemispheres (segments). The Plato's tetrahedron is a structural expression of this configuration: in this simplest polyhedron there is an opposition of a vertex (bulging, extension) and a face (pressing in, contraction). A convexo-concave shape of small bodies is very typical [1]; in some viewpoints they look as tetrahedrons [2]. The first overtone of the fundamental wave - wave 2 - produces structural octahedron (diamond). Rarely in a full shape, more often in its parts {rectilinear crossing outlines) this shape is rather typical in many obtained images of small bodies [3]. Not perfection of this polyhedron in reality is due to its superposition on a tetrahedron structure and complication by wave structures of the lower ranges, like a cube, dodecahedron, and impacts. Still, in some cases "diamond" in the sky is rather clear - Yanus (PIA 06613), Steins. Dr. Schwehm's prediction of even larger asteroid "diamond' in shape of Lutetia is really significant [4]. If small bodies are able to demonstrate their natural polyhedron shapes due to negligible gravity, the larger bodies are reduced to a globe shape by a mighty gravity. Still their structural layout (ubiquitous dichotomy), some protruding vertices, edges and faces betray their polyhedron nature. In this relation, "mysterious" Saturn's northern hexagon is a reflection of three crossing tetrahedron faces making the fourth face, while the southern hurricane is an imprint of an opposite vertex. Thus looks a hidden polyhedron in a globe. ESA-Rosetta mission is a real clue to an adequate understanding, deciphering forces sculpturing celestial bodies. Images of asteroid Steins revealing its clear polyhedron (diamond) shape witness to an involvement of warping wave processes. References: [1] Kochemasov G.G. (1999) On convexo-concave shape of small celestial bodies // "Asteroids, Comets, Meteors" conference, Cornell Univ., U.S.A., July 1999, Abstract # 24. 22; [2] Kochemasov G.G. (2008) Plato' polyhedra as shapes of small icy satellites // Geophys. Res. Abstracts, Vol. 10, EGU2008-A-01271, CD-ROM ; [3] Kochemasov G.G. (1999) "Diamond" and "dumb-bells"-like shapes of celestial bodies induced by inertia-gravity waves // 30th Vernadsky-Brown microsymposium on comparative planetology, Abstracts, Moscow, Vernadsky Inst.,, 49-50; [4] ESA News. Steins: a diamond in the sky, 6 September, 2008 (http://www.esa.int/rosetta);

21 CFR 882.4370 - Pneumatic cranial drill motor.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Pneumatic cranial drill motor. 882.4370 Section... drill motor. (a) Identification. A pneumatic cranial drill motor is a pneumatically operated power source used with removable rotating surgical cutting tools or drill bits on a patient's skull. (b...

21 CFR 882.4370 - Pneumatic cranial drill motor.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Pneumatic cranial drill motor. 882.4370 Section... drill motor. (a) Identification. A pneumatic cranial drill motor is a pneumatically operated power source used with removable rotating surgical cutting tools or drill bits on a patient's skull. (b...

21 CFR 882.4370 - Pneumatic cranial drill motor.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Pneumatic cranial drill motor. 882.4370 Section... drill motor. (a) Identification. A pneumatic cranial drill motor is a pneumatically operated power source used with removable rotating surgical cutting tools or drill bits on a patient's skull. (b...

Search for New Highly Energetic Phases under Compression and Shear

DTIC Science & Technology

2015-05-01

bar barn British thermal unit (thermochemical) calorie (thermochemical) cal (thermochemical/cm ) curie degree (angle) degree Fahrenheit...corresponding finite element algorithms and subroutines are developed. (c) Problems on compression and shear of a sample in rotational diamond anvil...element algorithms and subroutines are developed. Model problems on martensitic microstructure evolution are solved. (f) Experimental approaches to study

Conceptual design of a 10 to the 8th power bit magnetic bubble domain mass storage unit and fabrication, test and delivery of a feasibility model

NASA Technical Reports Server (NTRS)

1972-01-01

The conceptual design of a highly reliable 10 to the 8th power-bit bubble domain memory for the space program is described. The memory has random access to blocks of closed-loop shift registers, and utilizes self-contained bubble domain chips with on-chip decoding. Trade-off studies show that the highest reliability and lowest power dissipation is obtained when the memory is organized on a bit-per-chip basis. The final design has 800 bits/register, 128 registers/chip, 16 chips/plane, and 112 planes, of which only seven are activated at a time. A word has 64 data bits +32 checkbits, used in a 16-adjacent code to provide correction of any combination of errors in one plane. 100 KHz maximum rotational frequency keeps power low (equal to or less than, 25 watts) and also allows asynchronous operation. Data rate is 6.4 megabits/sec, access time is 200 msec to an 800-word block and an additional 4 msec (average) to a word. The fabrication and operation are also described for a 64-bit bubble domain memory chip designed to test the concept of on-chip magnetic decoding. Access to one of the chip's four shift registers for the read, write, and clear functions is by means of bubble domain decoders utilizing the interaction between a conductor line and a bubble.

Drilling systems for extraterrestrial subsurface exploration.

PubMed

Zacny, K; Bar-Cohen, Y; Brennan, M; Briggs, G; Cooper, G; Davis, K; Dolgin, B; Glaser, D; Glass, B; Gorevan, S; Guerrero, J; McKay, C; Paulsen, G; Stanley, S; Stoker, C

2008-06-01

Drilling consists of 2 processes: breaking the formation with a bit and removing the drilled cuttings. In rotary drilling, rotational speed and weight on bit are used to control drilling, and the optimization of these parameters can markedly improve drilling performance. Although fluids are used for cuttings removal in terrestrial drilling, most planetary drilling systems conduct dry drilling with an auger. Chip removal via water-ice sublimation (when excavating water-ice-bound formations at pressure below the triple point of water) and pneumatic systems are also possible. Pneumatic systems use the gas or vaporization products of a high-density liquid brought from Earth, gas provided by an in situ compressor, or combustion products of a monopropellant. Drill bits can be divided into coring bits, which excavate an annular shaped hole, and full-faced bits. While cylindrical cores are generally superior as scientific samples, and coring drills have better performance characteristics, full-faced bits are simpler systems because the handling of a core requires a very complex robotic mechanism. The greatest constraints to extraterrestrial drilling are (1) the extreme environmental conditions, such as temperature, dust, and pressure; (2) the light-time communications delay, which necessitates highly autonomous systems; and (3) the mission and science constraints, such as mass and power budgets and the types of drilled samples needed for scientific analysis. A classification scheme based on drilling depth is proposed. Each of the 4 depth categories (surface drills, 1-meter class drills, 10-meter class drills, and deep drills) has distinct technological profiles and scientific ramifications.

Elastic properties of transparent nano-polycrystalline diamond measured by GHz-ultrasonic interferometry and resonant sphere methods

NASA Astrophysics Data System (ADS)

Chang, Yun-Yuan; Jacobsen, Steven D.; Kimura, Masaki; Irifune, Tetsuo; Ohno, Ichiro

2014-03-01

The sound velocities and elastic moduli of transparent nano-polycrystalline diamond (NPD) have been determined by GHz-ultrasonic interferometry on three different bulk samples, and by resonant spectroscopy on a spherically fabricated NPD sample. We employ a newly-developed optical contact micrometer to measure the thickness of ultrasonic samples to ±0.05 μm with a spatial resolution of ∼50 μm in the same position of the GHz-ultrasonic measurements, resulting in acoustic-wave sound velocity measurements with uncertainties of 0.005-0.02%. The isotropic and adiabatic bulk and shear moduli of NPD measured by GHz-ultrasonic interferometry are KS0 = 442.5 (±0.5) GPa and G0 = 532.4 (±0.5) GPa. By rotating the shear-wave polarization direction, we observe no transverse anisotropy in this NPD. Using resonant sphere spectroscopy, we obtain KS0 = 440.3 (±0.5) GPa and G0 = 532.7 (±0.4) GPa. For comparison, we also measured by GHz-ultrasonic interferometry the elastic constants of a natural single-crystal type-IA diamond with about one-half the experimental uncertainty of previous measurements. The resulting Voigt-Reuss-Hill averaged bulk and shear moduli of natural diamond are KS0 = 441.8 (±0.8) GPa and G0 = 532.6 (±0.5) GPa, demonstrating that the bulk-elastic properties of transparent NPD are equivalent to natural single-crystal diamond as calculated from polycrystalline averaging of its elastic constants.

Servomotor and Controller Having Large Dynamic Range

NASA Technical Reports Server (NTRS)

Alhorn, Dean C.; Howard, David E.; Smith, Dennis A.; Dutton, Ken; Paulson, M. Scott

2007-01-01

A recently developed micro-commanding rotational-position-control system offers advantages of less mechanical complexity, less susceptibility to mechanical resonances, less power demand, less bulk, less weight, and lower cost, relative to prior rotational-position-control systems based on stepping motors and gear drives. This system includes a digital-signal- processor (DSP)-based electronic controller, plus a shaft-angle resolver and a servomotor mounted on the same shaft. Heretofore, micro-stepping has usually been associated with stepping motors, but in this system, the servomotor is micro-commanded in response to rotational-position feedback from the shaft-angle resolver. The shaft-angle resolver is of a four-speed type chosen because it affords four times the resolution of a single-speed resolver. A key innovative aspect of this system is its position-feedback signal- conditioning circuits, which condition the resolver output signal for multiple ranges of rotational speed. In the preferred version of the system, two rotational- speed ranges are included, but any number of ranges could be added to expand the speed range or increase resolution in particular ranges. In the preferred version, the resolver output is conditioned with two resolver-to-digital converters (RDCs). One RDC is used for speeds from 0.00012 to 2.5 rpm; the other RDC is used for speeds of 2.5 to 6,000 rpm. For the lower speed range, the number of discrete steps of RDC output per revolution was set at 262,144 (4 quadrants at 16 bits per quadrant). For the higher speed range, the number of discrete steps per revolution was set at 4,096 (4 quadrants at 10 bits per quadrant).

Noise-Resilient Quantum Computing with a Nitrogen-Vacancy Center and Nuclear Spins.

PubMed

Casanova, J; Wang, Z-Y; Plenio, M B

2016-09-23

Selective control of qubits in a quantum register for the purposes of quantum information processing represents a critical challenge for dense spin ensembles in solid-state systems. Here we present a protocol that achieves a complete set of selective electron-nuclear gates and single nuclear rotations in such an ensemble in diamond facilitated by a nearby nitrogen-vacancy (NV) center. The protocol suppresses internuclear interactions as well as unwanted coupling between the NV center and other spins of the ensemble to achieve quantum gate fidelities well exceeding 99%. Notably, our method can be applied to weakly coupled, distant spins representing a scalable procedure that exploits the exceptional properties of nuclear spins in diamond as robust quantum memories.

Quantum gyroscope based on Berry phase of spins in diamond

NASA Astrophysics Data System (ADS)

Song, Xuerui; Wang, Liujun; Diao, Wenting; Duan, Chongdi

2018-02-01

Gyroscope is the crucial sensor of the inertial navigation system, there is always high demand to improve the sensitivity and reduce the size of the gyroscopes. Using the NV center electronic spin and nuclear spin qubits in diamond, we introduce the research of new types of quantum gyroscopes based on the Berry phase shifts of the spin states during the rotation of the sensor systems. Compared with the performance of the traditional MEMS gyroscope, the sensitivity of the new types of quantum gyroscopes was highly improved and the spatial resolution was reduced to nano-scale. With the help of micro-manufacturing technology in the semiconductor industry, the quantum gyroscopes introduced here can be further integrated into chip-scale sensors.

Cracking of porcelain surfaces arising from abrasive grinding with a dental air turbine.

PubMed

Chang, Chee W; Waddell, J Neil; Lyons, Karl M; Swain, Michael V

2011-12-01

The purpose of this in vitro study was to evaluate porcelain cracking induced by abrasive grinding with a conventional dental air turbine and abrasive diamond burs. Four commercially available porcelains were examined-Wieland ALLUX, Wieland ZIROX, IPS e.max Ceram, and IPS Empress Esthetic Veneering porcelain. Sixty discs of each porcelain type were fabricated according to manufacturer instructions, followed by an auto-glaze cycle. Abrasive grinding using fine, extra-fine, and ultra-fine diamond burs was carried out, using a conventional dental air turbine. The grinding parameters were standardized with regard to the magnitude of the force applied, rotational speed of the diamond bur, and flow rate of the water coolant. A testing apparatus was used to control the magnitude of force applied during the grinding procedure. The ground surfaces were then examined under scanning electron microscope. Cracking was seen for all porcelain types when ground with the fine bur. Cracking was not seen for specimens ground with the extra-fine or the ultra-fine bur. Wet abrasive grinding with a conventional dental air turbine and fine grit diamond burs has the potential to cause cracking in the four porcelain types tested. Similar abrasive grinding with smaller grit size particles does not cause similar observable cracking. © 2011 by the American College of Prosthodontists.

Quantum memory operations in a flux qubit - spin ensemble hybrid system

NASA Astrophysics Data System (ADS)

Saito, S.; Zhu, X.; Amsuss, R.; Matsuzaki, Y.; Kakuyanagi, K.; Shimo-Oka, T.; Mizuochi, N.; Nemoto, K.; Munro, W. J.; Semba, K.

2014-03-01

Superconducting quantum bits (qubits) are one of the most promising candidates for a future large-scale quantum processor. However for larger scale realizations the currently reported coherence times of these macroscopic objects (superconducting qubits) has not yet reached those of microscopic systems (electron spins, nuclear spins, etc). In this context, a superconductor-spin ensemble hybrid system has attracted considerable attention. The spin ensemble could operate as a quantum memory for superconducting qubits. We have experimentally demonstrated quantum memory operations in a superconductor-diamond hybrid system. An excited state and a superposition state prepared in the flux qubit can be transferred to, stored in and retrieved from the NV spin ensemble in diamond. From these experiments, we have found the coherence time of the spin ensemble is limited by the inhomogeneous broadening of the electron spin (4.4 MHz) and by the hyperfine coupling to nitrogen nuclear spins (2.3 MHz). In the future, spin echo techniques could eliminate these effects and elongate the coherence time. Our results are a significant first step in utilizing the spin ensemble as long-lived quantum memory for superconducting flux qubits. This work was supported by the FIRST program and NICT.

Coherent coupling of a superconducting flux qubit to an electron spin ensemble in diamond.

PubMed

Zhu, Xiaobo; Saito, Shiro; Kemp, Alexander; Kakuyanagi, Kosuke; Karimoto, Shin-ichi; Nakano, Hayato; Munro, William J; Tokura, Yasuhiro; Everitt, Mark S; Nemoto, Kae; Kasu, Makoto; Mizuochi, Norikazu; Semba, Kouichi

2011-10-12

During the past decade, research into superconducting quantum bits (qubits) based on Josephson junctions has made rapid progress. Many foundational experiments have been performed, and superconducting qubits are now considered one of the most promising systems for quantum information processing. However, the experimentally reported coherence times are likely to be insufficient for future large-scale quantum computation. A natural solution to this problem is a dedicated engineered quantum memory based on atomic and molecular systems. The question of whether coherent quantum coupling is possible between such natural systems and a single macroscopic artificial atom has attracted considerable attention since the first demonstration of macroscopic quantum coherence in Josephson junction circuits. Here we report evidence of coherent strong coupling between a single macroscopic superconducting artificial atom (a flux qubit) and an ensemble of electron spins in the form of nitrogen-vacancy colour centres in diamond. Furthermore, we have observed coherent exchange of a single quantum of energy between a flux qubit and a macroscopic ensemble consisting of about 3 × 10(7) such colour centres. This provides a foundation for future quantum memories and hybrid devices coupling microwave and optical systems.

Repetitive readout of a single electronic spin via quantum logic with nuclear spin ancillae.

PubMed

Jiang, L; Hodges, J S; Maze, J R; Maurer, P; Taylor, J M; Cory, D G; Hemmer, P R; Walsworth, R L; Yacoby, A; Zibrov, A S; Lukin, M D

2009-10-09

Robust measurement of single quantum bits plays a key role in the realization of quantum computation and communication as well as in quantum metrology and sensing. We have implemented a method for the improved readout of single electronic spin qubits in solid-state systems. The method makes use of quantum logic operations on a system consisting of a single electronic spin and several proximal nuclear spin ancillae in order to repetitively readout the state of the electronic spin. Using coherent manipulation of a single nitrogen vacancy center in room-temperature diamond, full quantum control of an electronic-nuclear system consisting of up to three spins was achieved. We took advantage of a single nuclear-spin memory in order to obtain a 10-fold enhancement in the signal amplitude of the electronic spin readout. We also present a two-level, concatenated procedure to improve the readout by use of a pair of nuclear spin ancillae, an important step toward the realization of robust quantum information processors using electronic- and nuclear-spin qubits. Our technique can be used to improve the sensitivity and speed of spin-based nanoscale diamond magnetometers.

Rapid Active Sampling Package

NASA Technical Reports Server (NTRS)

Peters, Gregory

2010-01-01

A field-deployable, battery-powered Rapid Active Sampling Package (RASP), originally designed for sampling strong materials during lunar and planetary missions, shows strong utility for terrestrial geological use. The technology is proving to be simple and effective for sampling and processing materials of strength. Although this originally was intended for planetary and lunar applications, the RASP is very useful as a powered hand tool for geologists and the mining industry to quickly sample and process rocks in the field on Earth. The RASP allows geologists to surgically acquire samples of rock for later laboratory analysis. This tool, roughly the size of a wrench, allows the user to cut away swaths of weathering rinds, revealing pristine rock surfaces for observation and subsequent sampling with the same tool. RASPing deeper (.3.5 cm) exposes single rock strata in-situ. Where a geologist fs hammer can only expose unweathered layers of rock, the RASP can do the same, and then has the added ability to capture and process samples into powder with particle sizes less than 150 microns, making it easier for XRD/XRF (x-ray diffraction/x-ray fluorescence). The tool uses a rotating rasp bit (or two counter-rotating bits) that resides inside or above the catch container. The container has an open slot to allow the bit to extend outside the container and to allow cuttings to enter and be caught. When the slot and rasp bit are in contact with a substrate, the bit is plunged into it in a matter of seconds to reach pristine rock. A user in the field may sample a rock multiple times at multiple depths in minutes, instead of having to cut out huge, heavy rock samples for transport back to a lab for analysis. Because of the speed and accuracy of the RASP, hundreds of samples can be taken in one day. RASP-acquired samples are small and easily carried. A user can characterize more area in less time than by using conventional methods. The field-deployable RASP used a Ni/Cad rechargeable battery. Power usage was less than 1 Wh/ cm3 even when sampling strong basalts, so many samples could be taken on a single battery charge.

Sidewall penetrator for oil wells

NASA Technical Reports Server (NTRS)

Collins, E. R., Jr.

1981-01-01

Penetrator bores horizontal holes in well casing to increase trapped oil drainage. Several penetrators operated by common drive are inserted into well at once. Shaft, made from spiraling cable, rotates and thrusts simultaneously through rigid curvilinear guide tube forcing bit through casing into strata. Device pierces more deeply than armor-piercing bullets and shaped explosive charges.

Origami-based tunable truss structures for non-volatile mechanical memory operation.

PubMed

Yasuda, Hiromi; Tachi, Tomohiro; Lee, Mia; Yang, Jinkyu

2017-10-17

Origami has recently received significant interest from the scientific community as a method for designing building blocks to construct metamaterials. However, the primary focus has been placed on their kinematic applications by leveraging the compactness and auxeticity of planar origami platforms. Here, we present volumetric origami cells-specifically triangulated cylindrical origami (TCO)-with tunable stability and stiffness, and demonstrate their feasibility as non-volatile mechanical memory storage devices. We show that a pair of TCO cells can develop a double-well potential to store bit information. What makes this origami-based approach more appealing is the realization of two-bit mechanical memory, in which two pairs of TCO cells are interconnected and one pair acts as a control for the other pair. By assembling TCO-based truss structures, we experimentally verify the tunable nature of the TCO units and demonstrate the operation of purely mechanical one- and two-bit memory storage prototypes.Origami is a popular method to design building blocks for mechanical metamaterials. Here, the authors assemble a volumetric origami-based structure, predict its axial and rotational movements during folding, and demonstrate the operation of mechanical one- and two-bit memory storage.

Lunar deep drill apparatus

NASA Technical Reports Server (NTRS)

Harvey, Jill (Editor)

1989-01-01

A self contained, mobile drilling and coring system was designed to operate on the Lunar surface and be controlled remotely from earth. The system uses SKITTER (Spatial Kinematic Inertial Translatory Tripod Extremity Robot) as its foundation and produces Lunar core samples two meters long and fifty millimeters in diameter. The drill bit used for this is composed of 30 per carat diamonds in a sintered tungsten carbide matrix. To drill up to 50 m depths, the bit assembly will be attached to a drill string made from 2 m rods which will be carried in racks on SKITTER. Rotary power for drilling will be supplied by a Curvo-Synchronous motor. SKITTER is to support this system through a hexagonal shaped structure which will contain the drill motor and the power supply. A micro-coring drill will be used to remove a preliminary sample 5 mm in diameter and 20 mm long from the side of the core. This whole system is to be controlled from earth. This is carried out by a continuously monitoring PLC onboard the drill rig. A touch screen control console allows the operator on earth to monitor the progress of the operation and intervene if necessary.

Gigahertz dynamics of a strongly driven single quantum spin.

PubMed

Fuchs, G D; Dobrovitski, V V; Toyli, D M; Heremans, F J; Awschalom, D D

2009-12-11

Two-level systems are at the core of numerous real-world technologies such as magnetic resonance imaging and atomic clocks. Coherent control of the state is achieved with an oscillating field that drives dynamics at a rate determined by its amplitude. As the strength of the field is increased, a different regime emerges where linear scaling of the manipulation rate breaks down and complex dynamics are expected. By calibrating the spin rotation with an adiabatic passage, we have measured the room-temperature "strong-driving" dynamics of a single nitrogen vacancy center in diamond. With an adiabatic passage to calibrate the spin rotation, we observed dynamics on sub-nanosecond time scales. Contrary to conventional thinking, this breakdown of the rotating wave approximation provides opportunities for time-optimal quantum control of a single spin.

Resolution of x-ray parabolic compound refractive diamond lens defined at the home laboratory

NASA Astrophysics Data System (ADS)

Polyakov, S. N.; Zholudev, S. I.; Gasilov, S. V.; Martyushov, S. Yu.; Denisov, V. N.; Terentiev, S. A.; Blank, V. D.

2017-05-01

Here we demonstrate performance of an original lab system designed for testing of X-ray parabolic compound refractive lenses (CRL) manufactured from a high-quality single-crystalline synthetic diamond grown by the high-pressure hightemperature technique. The basic parameters of a diamond CRL comprised from 28 plano-concave lenses such as the focal length of 634 mm, transmissivity of 0.36, field of view of 1 mm and resolution of 6 µm have been determined. Usually such measurements are performed on synchrotron radiation facilities. In this work characterization of CRL was performed by means of instruments and components that are available for laboratories such as the Rigaku 9kW rotating anode X-ray generator, the PANalytical parallel beam X-ray mirror, a 6 m long optical bench, high precision multi-axis goniometers, high resolution X-ray emulsion films, and ultra-fast high-sensitive X-ray area detector PIXel3D. Developed setup was used to find differences between experimental and design parameters, which is very important for the improvement of CRLs manufacturing technology.

Computational modeling of the nonlinear stochastic dynamics of horizontal drillstrings

NASA Astrophysics Data System (ADS)

Cunha, Americo; Soize, Christian; Sampaio, Rubens

2015-11-01

This work intends to analyze the nonlinear stochastic dynamics of drillstrings in horizontal configuration. For this purpose, it considers a beam theory, with effects of rotatory inertia and shear deformation, which is capable of reproducing the large displacements that the beam undergoes. The friction and shock effects, due to beam/borehole wall transversal impacts, as well as the force and torque induced by bit-rock interaction, are also considered in the model. Uncertainties of bit-rock interaction model are taken into account using a parametric probabilistic approach. Numerical simulations have shown that the mechanical system of interest has a very rich nonlinear stochastic dynamics, which generate phenomena such as bit-bounce, stick-slip, and transverse impacts. A study aiming to maximize the drilling process efficiency, varying drillstring velocities of translation and rotation is presented. Also, the work presents the definition and solution of two optimizations problems, one deterministic and one robust, where the objective is to maximize drillstring rate of penetration into the soil respecting its structural limits.

Coherent attack on oblivious transfer based on single-qubit rotations

NASA Astrophysics Data System (ADS)

He, Guang Ping

2018-04-01

Recently a bit-string quantum oblivious transfer (OT) protocol based on single-qubit rotations was proposed (Rodrigues et al 2017 J. Phys. A: Math. Theor. 50 205301) and proven secure against few-qubit measurements. However, it was left as an open question whether the protocol remains secure against general attacks. Here, we close the gap by showing that if the receiver Bob can perform collective measurements on all qubits, then he can learn Alice’s secret message with a probability close to one. Thus the protocol fails to meet the security criterion of OT.

In Situ Real-Time Radiographic Study of Thin Film Formation Inside Rotating Hollow Spheres

DOE PAGES

Braun, Tom; Walton, Christopher C.; Dawedeit, Christoph; ...

2016-02-03

The hollow spheres with uniform coatings on the inner surface have applications in optical devices, time- or site-controlled drug release, heat storage devices, and target fabrication for inertial confinement fusion experiments. The fabrication of uniform coatings, which is often critical for the application performance, requires precise understanding and control over the coating process and its parameters. We report on in situ real-time radiography experiments that provide critical spatiotemporal information about the distribution of fluids inside hollow spheres during uniaxial rotation. Furthermore, image analysis and computer fluid dynamics simulations were used to explore the effect of liquid viscosity and rotational velocitymore » on the film uniformity. The data were then used to demonstrate the fabrication of uniform sol–gel chemistry derived porous polymer films inside 2 mm inner diameter diamond shells.« less

In Situ Real-Time Radiographic Study of Thin Film Formation Inside Rotating Hollow Spheres

DOE Office of Scientific and Technical Information (OSTI.GOV)

Braun, Tom; Walton, Christopher C.; Dawedeit, Christoph

2016-02-03

Hollow spheres with uniform coatings on the inner surface have applications in optical devices, time- or site controlled drug release, heat storage devices, and target fabrication for inertial confinement fusion experiments. The fabrication of uniform coatings, which is often critical for the application performance, requires precise understanding and control over the coating process and its parameters. Here, we report on in-situ real-time radiography experiments that provide critical spatio-temporal information about the distribution of fluids inside hollow spheres during uniaxial rotation. Image analysis and computer fluid dynamics simulations were used to explore the effect of liquid viscosity and rotational velocity onmore » the film uniformity. The data were then used to demonstrate the fabrication of uniform sol-gel chemistry derived porous polymer films inside 2mm inner diameter diamond shells.« less

Optimization of Operating Parameters for Minimum Mechanical Specific Energy in Drilling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hamrick, Todd

2011-01-01

Efficiency in drilling is measured by Mechanical Specific Energy (MSE). MSE is the measure of the amount of energy input required to remove a unit volume of rock, expressed in units of energy input divided by volume removed. It can be expressed mathematically in terms of controllable parameters; Weight on Bit, Torque, Rate of Penetration, and RPM. It is well documented that minimizing MSE by optimizing controllable factors results in maximum Rate of Penetration. Current methods for computing MSE make it possible to minimize MSE in the field only through a trial-and-error process. This work makes it possible to computemore » the optimum drilling parameters that result in minimum MSE. The parameters that have been traditionally used to compute MSE are interdependent. Mathematical relationships between the parameters were established, and the conventional MSE equation was rewritten in terms of a single parameter, Weight on Bit, establishing a form that can be minimized mathematically. Once the optimum Weight on Bit was determined, the interdependent relationship that Weight on Bit has with Torque and Penetration per Revolution was used to determine optimum values for those parameters for a given drilling situation. The improved method was validated through laboratory experimentation and analysis of published data. Two rock types were subjected to four treatments each, and drilled in a controlled laboratory environment. The method was applied in each case, and the optimum parameters for minimum MSE were computed. The method demonstrated an accurate means to determine optimum drilling parameters of Weight on Bit, Torque, and Penetration per Revolution. A unique application of micro-cracking is also presented, which demonstrates that rock failure ahead of the bit is related to axial force more than to rotation speed.« less

Loophole-free Bell test using electron spins in diamond: second experiment and additional analysis

PubMed Central

Hensen, B.; Kalb, N.; Blok, M. S.; Dréau, A. E.; Reiserer, A.; Vermeulen, R. F. L.; Schouten, R. N.; Markham, M.; Twitchen, D. J.; Goodenough, K.; Elkouss, D.; Wehner, S.; Taminiau, T. H.; Hanson, R.

2016-01-01

The recently reported violation of a Bell inequality using entangled electronic spins in diamonds (Hensen et al., Nature 526, 682–686) provided the first loophole-free evidence against local-realist theories of nature. Here we report on data from a second Bell experiment using the same experimental setup with minor modifications. We find a violation of the CHSH-Bell inequality of 2.35 ± 0.18, in agreement with the first run, yielding an overall value of S = 2.38 ± 0.14. We calculate the resulting P-values of the second experiment and of the combined Bell tests. We provide an additional analysis of the distribution of settings choices recorded during the two tests, finding that the observed distributions are consistent with uniform settings for both tests. Finally, we analytically study the effect of particular models of random number generator (RNG) imperfection on our hypothesis test. We find that the winning probability per trial in the CHSH game can be bounded knowing only the mean of the RNG bias. This implies that our experimental result is robust for any model underlying the estimated average RNG bias, for random bits produced up to 690 ns too early by the random number generator. PMID:27509823

A Museum of the Indian, Not for the Indian

ERIC Educational Resources Information Center

Lujan, James

2005-01-01

There has been some controversy brewing around the Smithsonian's National Museum of the American Indian (NMAI). A bit of it is due to the dismay over the exclusion of so many tribes, which in time will be remedied, given that the exhibits are supposed to rotate every couple of years. But more fundamental is the debate over the museum's deliberate…

Combination process of diamond machining and roll-to-roll UV-replication for thin film micro- and nanostructures

NASA Astrophysics Data System (ADS)

Väyrynen, J.; Mönkkönen, K.; Siitonen, S.

2016-09-01

Roll-to-roll (R2R) ultraviolet (UV) curable embossing replication process is a highly accurate and cost effective way to replicate large quantities of thin film polymer parts. These structures can be used for microfluidics, LED-optics, light guides, displays, cameras, diffusers, decorative, laser sensing and measuring devices. In the R2R UV-process, plastic thin film coated with UV-curable lacquer, passes through an imprinting embossing drum and is then hardened by an UV-lamp. One key element for mastering this process is the ability to manufacture a rotating drum containing micro- and nanostructures. Depending on the pattern shapes, the drum can be directly machined by diamond machining or it can be done through wafer level lithographical process. Due to the shrinkage of UV-curable lacquer, the R2R drum pattern process needs to be prototyped few times, in order to get the desired performance and shape from the R2R produced part. To speed up the prototyping and overall process we have developed a combination process where planar diamond machining patterns are being turned into a drum roller. Initially diamond machined patterns from a planar surface are replicated on a polymer sheet using UV-replication. Secondly, a nickel stamper shim is grown form the polymer sheet and at the end the stamper is turned into a roller and used in the R2R process. This process allows various micro milled, turned, grooved and ruled structures to be made at thin film products through the R2R process. In this paper, the process flow and examples of fabricating R2R embossed UVcurable thin film micro- and nanostructures from planar diamond machined patterns, is reported.

Freeform manufacturing of a microoptical lens array on a steep curved substrate by use of a voice coil fast tool servo.

PubMed

Scheiding, Sebastian; Yi, Allen Y; Gebhardt, Andreas; Li, Lei; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas

2011-11-21

We report what is to our knowledge the first approach to diamond turn microoptical lens array on a steep curved substrate by use of a voice coil fast tool servo. In recent years ultraprecision machining has been employed to manufacture accurate optical components with 3D structure for beam shaping, imaging and nonimaging applications. As a result, geometries that are difficult or impossible to manufacture using lithographic techniques might be fabricated using small diamond tools with well defined cutting edges. These 3D structures show no rotational symmetry, but rather high frequency asymmetric features thus can be treated as freeform geometries. To transfer the 3D surface data with the high frequency freeform features into a numerical control code for machining, the commonly piecewise differentiable surfaces are represented as a cloud of individual points. Based on this numeric data, the tool radius correction is calculated to account for the cutting-edge geometry. Discontinuities of the cutting tool locations due to abrupt slope changes on the substrate surface are bridged using cubic spline interpolation.When superimposed with the trajectory of the rotationally symmetric substrate the complete microoptical geometry in 3D space is established. Details of the fabrication process and performance evaluation are described. © 2011 Optical Society of America

Pixelated transmission-mode diamond X-ray detector.

PubMed

Zhou, Tianyi; Ding, Wenxiang; Gaowei, Mengjia; De Geronimo, Gianluigi; Bohon, Jen; Smedley, John; Muller, Erik

2015-11-01

Fabrication and testing of a prototype transmission-mode pixelated diamond X-ray detector (pitch size 60-100 µm), designed to simultaneously measure the flux, position and morphology of an X-ray beam in real time, are described. The pixel density is achieved by lithographically patterning vertical stripes on the front and horizontal stripes on the back of an electronic-grade chemical vapor deposition single-crystal diamond. The bias is rotated through the back horizontal stripes and the current is read out on the front vertical stripes at a rate of ∼ 1 kHz, which leads to an image sampling rate of ∼ 30 Hz. This novel signal readout scheme was tested at beamline X28C at the National Synchrotron Light Source (white beam, 5-15 keV) and at beamline G3 at the Cornell High Energy Synchrotron Source (monochromatic beam, 11.3 keV) with incident beam flux ranges from 1.8 × 10(-2) to 90 W mm(-2). Test results show that the novel detector provides precise beam position (positional noise within 1%) and morphology information (error within 2%), with an additional software-controlled single channel mode providing accurate flux measurement (fluctuation within 1%).

Advanced laser diagnostics for diamond deposition research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kruger, C.H.; Owano, T.G.; Wahl, E.H.

Chemical Vapor Deposition (CVD) using thermal plasmas is attractive for diamond synthesis applications due to the inherently high reactant densities and throughput, but the associated high gas-phase collision rates in the boundary layer above the substrate produce steep thermal and species gradients which can drive the complex plasma chemistry away from optimal conditions. To understand and control these environments, accurate measurements of temperature and species concentrations within the reacting boundary layer are needed. This is challenging in atmospheric pressure reactors due to the highly luminous environment, steep thermal and species gradients, and small spatial scales. The applicability of degenerate four-wavemore » mixing (DFWM) as a spectroscopic probe of atmospheric pressure reacting plasmas has been investigated. This powerful, nonlinear technique has been applied to the measurement of temperature and radical species concentrations in the boundary layer of a diamond growth substrate immersed in a flowing atmospheric pressure plasma. In-situ measurements of CH and C{sub 2} radicals have been performed to determine spatially resolved profiles of vibrational temperature, rotational temperature, and species concentration. Results of these measurements are compared with the predictions of a detailed numerical simulation.« less

Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic

NASA Astrophysics Data System (ADS)

Lovchinsky, I.; Sushkov, A. O.; Urbach, E.; de Leon, N. P.; Choi, S.; De Greve, K.; Evans, R.; Gertner, R.; Bersin, E.; Müller, C.; McGuinness, L.; Jelezko, F.; Walsworth, R. L.; Park, H.; Lukin, M. D.

2016-02-01

Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition.

An evaluation of the effects of handpiece speed, abrasive characteristics, and polishing load on the flexural strength of polished ceramics.

PubMed

Ahmad, Rohana; Morgano, Steven M; Wu, Benjamin M; Giordano, Russell A

2005-11-01

Many studies on the strengthening effects of grinding and polishing, as well as heat treatment on ceramics, are not well standardized or use commercially available industrial polishing systems. The reported effectiveness of these strengthening mechanisms on ceramics may not be applicable to clinical dentistry. The purpose of this study was to evaluate the effects of controlled polishing on the flexural strength of dental ceramics by using a custom-made machine that applied standardized loads and speeds that coincided with the mean loads and speeds used by experienced prosthodontists. A total of 140 aluminous dental ceramic bar-shaped specimens (Vitadur Alpha Enamel) measuring 1.5 x 2.0 x 25 mm were fabricated and divided into 12 groups (for most groups, n=10). Specimens were untreated, polished with different polishing systems, polished at different speeds, ground and autoglazed, polished and autoglazed, autoglazed and polished, polished with loose (paste) and bonded abrasives, or overglazed. Simulated clinical polishing was performed on the ceramic specimens by using a customized polishing apparatus that allowed independent control over the relevant polishing parameters (abrasive hardness, applied load, linear speed, rotational velocity, and wheel stiffness). Flexural strength (MPa) was measured with a 4-point bending test, and subjective surface roughness was assessed with scanning electron microscopy. Autoglazing was performed at various stages of the polishing sequence to determine the effects of polishing on surface stresses. Mean values, standard deviations, independent-sample t tests, 1-way and 2-way analyses of variance, Dunnett t tests and Kruskal-Wallis tests were applied to the data (alpha=.05). Under a clinical load of 0.6 N for a coarse polishing wheel, 1.0 N for a medium polishing wheel, and 1.3 N for a fine polishing wheel, a linear speed of 499 mm/min, and a rotational velocity of 10,000 rpm, the use of clinical polishing instruments did not affect the flexural strength of the aluminous ceramics studied (P=.274). At higher rotational velocity (20,000 rpm), specimens polished with the diamond polishing system produced statistically weaker specimens compared with those that had been polished at 10,000 rpm (P=.019). Autoglazing treatment of the diamond-polished specimens did not reverse the strength degradation (P=.125). Conversely, diamond polishing of the autoglazed specimens resulted in significant flexural strength reduction (P=.029). Fine-diamond-bonded abrasive significantly reduced flexural strength (P=.025). Simulated clinical polishing at 10,000 rpm did not appear to substantially strengthen or weaken the ceramic specimens. Polishing at 20,000 rpm reduced flexural strength of the ceramic bars.

Retractable tool bit having latch type catch mechanism

NASA Technical Reports Server (NTRS)

Voellmer, George (Inventor)

1993-01-01

A retractable tool bit assembly for a tool such as an allen key is presented. The assembly includes one or more spring loaded nestable or telescoping tubular sections together with a catch mechanism for capturing and holding the tool in its retracted position. The catch mechanism consists of a latch mechanism located in a base section and which engages a conically shaped tool head located at the inner end of the tool. The tool head adjoins an eccentric oval type neck portion which extends to a rear lip of the tool head. The latch mechanism releases when the ovular neck portion rotates about the catch members upon actuation of a rotary tool drive motor. When released, all the telescoping sections and the tool extends fully outward to a use position.

Casing window milling with abrasive fluid jet

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vestavik, O.M.; Fidtje, T.H.; Faure, A.M.

1995-12-31

Methods for through tubing re-entry drilling of multilateral wells has a large potential for increasing hydrocarbon production and total recovery. One of the bottle-necks of this technology is initiation of the side-track by milling a window in the casing downhole. A new approach to this problem has been investigated in a joint industry project. An experimental set-up has been built for milling a 4 inch window in a 7 inch steel casing at surface in the laboratory. A specially designed bit developed at RIF using abrasive jet cutting technology has been used for the window milling. The bit has anmore » abrasive jet beam which is always directed in the desired side-track direction, even if the bit is rotating uniformly. The bit performs the milling with a combined mechanical and hydraulic jet action. The method has been successfully demonstrated. The experiments has shown that the window milling can be performed with very low WOB and torque, and that only small side forces are required to perform the operation. Casing milling has been performed without a whipstock, a cement plug has been the only support for the tool. The tests indicate that milling operations can be performed more efficiently with less time and costs than what is required with conventional techniques. However, the method still needs some development of the downhole motor for coiled tubing applications. The method can be used both for milling and drilling giving the advantage of improved rate of penetration, improved bit life and increased horizontal reach. The method is planned to be demonstrated downhole in the near future.« less

Roughness Induced Transition in a Supersonic Boundary Layer

NASA Technical Reports Server (NTRS)

Balakumar, Ponnampalam; Kergerise, Michael A.

2013-01-01

Direct numerical simulation is used to investigate the transition induced by threedimensional isolated roughness elements in a supersonic boundary layer at a free stream Mach number of 3.5. Simulations are performed for two different configurations: one is a square planform roughness and the other is a diamond planform roughness. The mean-flow calculations show that the roughness induces counter rotating streamwise vortices downstream of the roughness. These vortices persist for a long distance downstream and lift the low momentum fluid from the near wall region and place it near the outer part of the boundary layer. This forms highly inflectional boundary layer profiles. These observations agree with recent experimental observations. The receptivity calculations showed that the amplitudes of the mass-flux fluctuations near the neutral point for the diamond shape roughness are the same as the amplitude of the acoustic disturbances. They are three times smaller for the square shape roughness.

Acceptability of mHealth Technology for Self-Monitoring Eating and Activity among Rural Men.

PubMed

Eisenhauer, Christine M; Hageman, Patricia A; Rowland, Sheri; Becker, Betsy J; Barnason, Susan A; Pullen, Carol H

2017-03-01

To examine rural men's use and perceptions of mobile and wireless devices to self-monitor eating and physical activity (mHealth). Men in this 3-week pilot study used FitBit One ® to log daily food intake and monitor activity. A companion application (app) allowed activity monitoring of fellow participants. Health-related text messages were received 1-3 times daily. A purposive sample of 12 rural men (ages 40-67) was recruited by community leaders. (1) baseline heart rate, blood pressure, and BMI, (2) FitBit One ® usage, (3) investigator-generated surveys on acceptability of mHealth, and (4) focus group on experience with mHealth. Men were overweight (n = 3) or obese (n = 9) and 9 of 12 were hypertensive. Nine of twelve wore FitBit One ® all 21 days. Eleven of 12 men logged food, with 9 of 12 doing this at least 15 of 21 days. Self-monitoring and daily text messaging increased awareness of energy intake and output. Companion app's food log needed targeting for rural foods. Rotating seasons (occupational, religious, recreational) and weak cellular signals created contextual barriers to self-monitoring eating and activity. FitBit One ® and text messaging were perceived as useful among the rural men, while the companion apps require adaptation to reflect dietary norms. © 2016 Wiley Periodicals, Inc.

Economics of ingot slicing with an internal diameter saw for low-cost solar cells

NASA Technical Reports Server (NTRS)

Daud, T.; Liu, J. K.; Fiegl, G.

1981-01-01

Slicing of silicon ingots using diamond impregnated internal diameter blade saws has been a standard technology of the semiconductor industry. This paper describes work on improvements to this technology for 10 cm diameter ingot slicing. Ingot rotation, dynamic blade edge control with feedback, mechanized blade dressing and development of thinner blades are the approaches tried. A comparison of the results for wafering with and without ingot rotation is also made. A sensitivity analysis of the major cost elements in wafering is performed for 10 cm diameter ingot and extended to the 15 cm diameter ingot case. Various parameter values such as machine cost, feed rate and consumable materials cost are identified both for single and multiple ingot slicing.

Inertial rotation measurement with atomic spins: From angular momentum conservation to quantum phase theory

NASA Astrophysics Data System (ADS)

Zhang, C.; Yuan, H.; Tang, Z.; Quan, W.; Fang, J. C.

2016-12-01

Rotation measurement in an inertial frame is an important technology for modern advanced navigation systems and fundamental physics research. Inertial rotation measurement with atomic spin has demonstrated potential in both high-precision applications and small-volume low-cost devices. After rapid development in the last few decades, atomic spin gyroscopes are considered a promising competitor to current conventional gyroscopes—from rate-grade to strategic-grade applications. Although it has been more than a century since the discovery of the relationship between atomic spin and mechanical rotation by Einstein [Naturwissenschaften, 3(19) (1915)], research on the coupling between spin and rotation is still a focus point. The semi-classical Larmor precession model is usually adopted to describe atomic spin gyroscope measurement principles. More recently, the geometric phase theory has provided a different view of the rotation measurement mechanism via atomic spin. The theory has been used to describe a gyroscope based on the nuclear spin ensembles in diamond. A comprehensive understanding of inertial rotation measurement principles based on atomic spin would be helpful for future applications. This work reviews different atomic spin gyroscopes and their rotation measurement principles with a historical overlook. In addition, the spin-rotation coupling mechanism in the context of the quantum phase theory is presented. The geometric phase is assumed to be the origin of the measurable rotation signal from atomic spins. In conclusion, with a complete understanding of inertial rotation measurements using atomic spin and advances in techniques, wide application of high-performance atomic spin gyroscopes is expected in the near future.

Nuclear magnetic resonance detection and spectroscopy of single proteins using quantum logic.

PubMed

Lovchinsky, I; Sushkov, A O; Urbach, E; de Leon, N P; Choi, S; De Greve, K; Evans, R; Gertner, R; Bersin, E; Müller, C; McGuinness, L; Jelezko, F; Walsworth, R L; Park, H; Lukin, M D

2016-02-19

Nuclear magnetic resonance spectroscopy is a powerful tool for the structural analysis of organic compounds and biomolecules but typically requires macroscopic sample quantities. We use a sensor, which consists of two quantum bits corresponding to an electronic spin and an ancillary nuclear spin, to demonstrate room temperature magnetic resonance detection and spectroscopy of multiple nuclear species within individual ubiquitin proteins attached to the diamond surface. Using quantum logic to improve readout fidelity and a surface-treatment technique to extend the spin coherence time of shallow nitrogen-vacancy centers, we demonstrate magnetic field sensitivity sufficient to detect individual proton spins within 1 second of integration. This gain in sensitivity enables high-confidence detection of individual proteins and allows us to observe spectral features that reveal information about their chemical composition. Copyright © 2016, American Association for the Advancement of Science.

Pixelated transmission-mode diamond X-ray detector

PubMed Central

Zhou, Tianyi; Ding, Wenxiang; Gaowei, Mengjia; De Geronimo, Gianluigi; Bohon, Jen; Smedley, John; Muller, Erik

2015-01-01

Fabrication and testing of a prototype transmission-mode pixelated diamond X-ray detector (pitch size 60–100 µm), designed to simultaneously measure the flux, position and morphology of an X-ray beam in real time, are described. The pixel density is achieved by lithographically patterning vertical stripes on the front and horizontal stripes on the back of an electronic-grade chemical vapor deposition single-crystal diamond. The bias is rotated through the back horizontal stripes and the current is read out on the front vertical stripes at a rate of ∼1 kHz, which leads to an image sampling rate of ∼30 Hz. This novel signal readout scheme was tested at beamline X28C at the National Synchrotron Light Source (white beam, 5–15 keV) and at beamline G3 at the Cornell High Energy Synchrotron Source (monochromatic beam, 11.3 keV) with incident beam flux ranges from 1.8 × 10−2 to 90 W mm−2. Test results show that the novel detector provides precise beam position (positional noise within 1%) and morphology information (error within 2%), with an additional software-controlled single channel mode providing accurate flux measurement (fluctuation within 1%). PMID:26524304

A bandwidth efficient coding scheme for the Hubble Space Telescope

NASA Technical Reports Server (NTRS)

Pietrobon, Steven S.; Costello, Daniel J., Jr.

1991-01-01

As a demonstration of the performance capabilities of trellis codes using multidimensional signal sets, a Viterbi decoder was designed. The choice of code was based on two factors. The first factor was its application as a possible replacement for the coding scheme currently used on the Hubble Space Telescope (HST). The HST at present uses the rate 1/3 nu = 6 (with 2 (exp nu) = 64 states) convolutional code with Binary Phase Shift Keying (BPSK) modulation. With the modulator restricted to a 3 Msym/s, this implies a data rate of only 1 Mbit/s, since the bandwidth efficiency K = 1/3 bit/sym. This is a very bandwidth inefficient scheme, although the system has the advantage of simplicity and large coding gain. The basic requirement from NASA was for a scheme that has as large a K as possible. Since a satellite channel was being used, 8PSK modulation was selected. This allows a K of between 2 and 3 bit/sym. The next influencing factor was INTELSAT's intention of transmitting the SONET 155.52 Mbit/s standard data rate over the 72 MHz transponders on its satellites. This requires a bandwidth efficiency of around 2.5 bit/sym. A Reed-Solomon block code is used as an outer code to give very low bit error rates (BER). A 16 state rate 5/6, 2.5 bit/sym, 4D-8PSK trellis code was selected. This code has reasonable complexity and has a coding gain of 4.8 dB compared to uncoded 8PSK (2). This trellis code also has the advantage that it is 45 deg rotationally invariant. This means that the decoder needs only to synchronize to one of the two naturally mapped 8PSK signals in the signal set.

Versatile optical system for static and dynamic thermomagnetic recording using a scanning laser microscope

NASA Astrophysics Data System (ADS)

Clegg, Warwick W.; Jenkins, David F. L.; Helian, Na; Windmill, James; Windmill, Robert

2001-12-01

Scanning Laser Microscopes (SLM) have been used to characterise the magnetic domain properties of various magnetic and magneto-optical materials. The SLM in our laboratory has been designed to enable both static and dynamic read-write operations to be performed on stationary media. In a conventional (static) SLM, data bits are recorded thermo-magnetically by focusing a pulse of laser light onto the sample surface. If the laser beam has a Gaussian intensity distribution (TEM00) then so will the focused laser spot. The resultant temperature profile will largely mirror the intensity distribution of the focused spot, and in the region where the temperature is sufficiently high for switching to occur, in the presence of bias field, a circular data bit will be recorded. However, in a real magneto-optical drive the bits are written onto non-stationary media, and the resultant bit will be non-circular. A versatile optical system has been developed to facilitate both recording and imaging of data bits. To simulate the action of a Magneto-Optical drive, the laser is pulsed via an Acousto-Optic Modulator, whilst being scanned across the sample using a galvanometer mounted mirror, thus imitating a storage medium rotating above a MO head with high relative velocity between the beam and medium. Static recording is simply achieved by disabling the galvanometer scan mirror. Polar magneto-optic Kerr effect images are acquired using multiple-segment photo-detectors for diffraction-limited scanned spot detection, with either specimen scanning for highest resolution or beam scanning for near real-time image acquisition. Results will be presented to illustrate the systems capabilities.

Cerebellum Augmented Rover Development

NASA Technical Reports Server (NTRS)

King, Matthew

2005-01-01

Bio-Inspired Technologies and Systems (BITS) are a very natural result of thinking about Nature's way of solving problems. Knowledge of animal behaviors an be used in developing robotic behaviors intended for planetary exploration. This is the expertise of the JFL BITS Group and has served as a philosophical model for NMSU RioRobolab. Navigation is a vital function for any autonomous system. Systems must have the ability to determine a safe path between their current location and some target location. The MER mission, as well as other JPL rover missions, uses a method known as dead-reckoning to determine position information. Dead-reckoning uses wheel encoders to sense the wheel's rotation. In a sandy environment such as Mars, this method is highly inaccurate because the wheels will slip in the sand. Improving positioning error will allow the speed of an autonomous navigating rover to be greatly increased. Therefore, local navigation based upon landmark tracking is desirable in planetary exploration. The BITS Group is developing navigation technology based upon landmark tracking. Integration of the current rover architecture with a cerebellar neural network tracking algorithm will demonstrate that this approach to navigation is feasible and should be implemented in future rover and spacecraft missions.

Micro/nano electro mechanical systems for practical applications

NASA Astrophysics Data System (ADS)

Esashi, Masayoshi

2009-09-01

Silicon MEMS as electrostatically levitated rotational gyroscope, 2D optical scanner and wafer level packaged devices as integrated capacitive pressure sensor and MEMS switch are described. MEMS which use non-silicon materials as diamond, PZT, conductive polymer, CNT (carbon nano tube), LTCC with electrical feedthrough, SiC (silicon carbide) and LiNbO3 for multi-probe data storage, multi-column electron beam lithography system, probe card for wafer-level burn-in test, mould for glass press moulding and SAW wireless passive sensor respectively are also described.

Novel portable press for synchrotron time-resolved 3-D micro-imagining under extreme conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Philippe, J.; Le Godec, Y., E-mail: yann.legodec@impmc.upmc.fr; Bergame, F.

Here we present the instrumental development to extend the synchrotron X-ray microtomography techniques to in situ studies under static compression (HP) or shear stress or the both conditions at high temperatures (HT). To achieve this, a new rotating tomography Paris-Edinburgh cell (rotoPEc) has been developed. This ultra-compact portable device, easily and successfully adapted to various multi-modal synchrotron experimental set-up at ESRF, SOLEIL and DIAMOND is explained in detail.

Application of morphological bit planes in retinal blood vessel extraction.

PubMed

Fraz, M M; Basit, A; Barman, S A

2013-04-01

The appearance of the retinal blood vessels is an important diagnostic indicator of various clinical disorders of the eye and the body. Retinal blood vessels have been shown to provide evidence in terms of change in diameter, branching angles, or tortuosity, as a result of ophthalmic disease. This paper reports the development for an automated method for segmentation of blood vessels in retinal images. A unique combination of methods for retinal blood vessel skeleton detection and multidirectional morphological bit plane slicing is presented to extract the blood vessels from the color retinal images. The skeleton of main vessels is extracted by the application of directional differential operators and then evaluation of combination of derivative signs and average derivative values. Mathematical morphology has been materialized as a proficient technique for quantifying the retinal vasculature in ocular fundus images. A multidirectional top-hat operator with rotating structuring elements is used to emphasize the vessels in a particular direction, and information is extracted using bit plane slicing. An iterative region growing method is applied to integrate the main skeleton and the images resulting from bit plane slicing of vessel direction-dependent morphological filters. The approach is tested on two publicly available databases DRIVE and STARE. Average accuracy achieved by the proposed method is 0.9423 for both the databases with significant values of sensitivity and specificity also; the algorithm outperforms the second human observer in terms of precision of segmented vessel tree.

Radiation from an accelerating neutral body: The case of rotation

NASA Astrophysics Data System (ADS)

Yarman, Tolga; Arik, Metin; Kholmetskii, Alexander L.

2013-11-01

When an object is bound at rest to an attractional field, its rest mass (owing to the law of energy conservation, including the mass and energy equivalence of the Special Theory of Relativity) must decrease. The mass deficiency coming into play indicates a corresponding rest energy discharge. Thus, bringing an object to a rotational motion means that the energy transferred for this purpose serves to extract just as much rest mass (or similarly "rest energy", were the speed of light in empty space taken to be unity) out of it. Here, it is shown that during angular acceleration, photons of fundamental energy are emitted, while the object is kept on being delivered to a more and more intense rotational accelerational field, being the instantaneous angular velocity of the rotating object. This fundamental energy, as seen, does not depend on anything else (such as the mass or charge of the object), and it is in harmony with Bohr's Principle of Correspondence. This means at the same time, that emission will be achieved, as long as the angular velocity keeps on increasing, and will cease right after the object reaches a stationary rotational motion (a constant centrifugal acceleration), but if the object were brought to rotation in vacuum with no friction. By the same token, one can affirm that even the rotation at a macroscopic level is quantized, and can only take on "given angular velocities" (which can only be increased, bit by bit). The rate of emission of photons of concern is, on the other hand, proportional to the angular acceleration of the object, similarly to the derivative of the tangential acceleration with respect to time. It is thus constant for a "constant angular acceleration", although the energy of the emitted photons will increase with increasing , until the rotation reaches a stationary level, after which we expect no emission --let us stress-- if the object is in rotation in vacuum, along with no whatsoever friction (such as the case of a rotating diatomic molecule, for instance). If the object reaches its final state in a given medium, say air, and "friction" is present, such as the case of a dental drill, then energy should keep being supplied to it, to overcome friction, which is present either inside the "inner mechanism of rotation" or in its surroundings. In other words, the object in the latter case, would be constantly subject to a friction force, countering its motion, and tending to make it fall to lower rotational energy states. Any fluctuations in the power supply, on the other hand, will slow down the rotating object, no matter how indiscernibly. The small decrease in the rotational velocity is yet reincreased by restoring the power supply, thus perpetually securing a stationary rotational motion. Thereby, the object in this final state, due to fluctuations in either friction or power supply, or both, shall further be expected to emit a radiation of energy , where is the final angular velocity of the object in rotation. What is more is that our team has very successfully measured what is predicted here, and they will report their experimental results in a subsequent article. The approach presented here seems to shed light on the mysterious sonoluminescence. It also triggers the possibility of sensing earthquakes due to radiation that should be emitted by the faults, on which the seismic stress keeps increasing until the crackdown. By the same token, also two colliding (neutral) objects are expected to emit radiation.

Chemometric study on the electrochemical incineration of diethylenetriaminepentaacetic acid using boron-doped diamond anode.

PubMed

Xian, Jiahui; Liu, Min; Chen, Wei; Zhang, Chunyong; Fu, Degang

2018-05-01

The electrochemical incineration of diethylenetriaminepentaacetic acid (DTPA) with boron-doped diamond (BDD) anode had been initially performed under galvanostatic conditions. The main and interaction effects of four operating parameters (flow rate, applied current density, sulfate concentration and initial DTPA concentration) on mineralization performance were investigated. Under similar experimental conditions, Doehlert matrix (DM) and central composite rotatable design (CCRD) were used as statistical multivariate methods in the optimization of the anodic oxidation processes. A comparison between DM model and CCRD model revealed that the former was more accurate, possibly due to its higher operating level numbers employed (7 levels for two variables). Despite this, these two models resulted in quite similar optimum operating conditions. The maximum TOC removal percentages at 180 min were 76.2% and 73.8% for case of DM and CCRD, respectively. In addition, with the aid of quantum chemistry calculation and LC/MS analysis, a plausible degradation sequence of DTPA on BDD anode was also proposed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Demultiplexer for wavelength division multiplexing over polymer optical fibers applicable for high-volume production

NASA Astrophysics Data System (ADS)

Fischer, Ulrich H. P.; Höll, Sebastian; Haupt, Matthias; Joncic, Mladen

2015-10-01

Polymer optical fibers (POF) offer only transmission so far with one wavelength at 650 nm. In order to increase the overall transfer rate, the key element for wavelength division multiplexing (WDM) over POF will be presented. This element is a demultiplexer (DEMUX), which was designed in polymethylmethacrylate with an optical grating on an aspherical mirror to be produced by injection molding in a further development steps. The master was produced by diamond turning as a master for injection molding replication. The results of the different simulations followed by the development steps and the measurements of the prototype are presented. This prototype is used as a DEMUX in a WDM system with four wavelengths. In the WDM system, bit-error ratio (BER) measurements with an 8.26 Gb/s cumulated data rate in an offline processed discrete multitone modulation technique have been achieved over 100 m SI-POF at a BER of 10-3.

Development of seals for a geothermal downhole intensifier. Progress report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Captain, K.M.; Harvey, A.C.; Caskey, B.C.

1985-08-01

A system using high-velocity fluid jets in conjunction with a rotary diamond bit is currently considered as the best candidate for reducing the cost of drilling geothermal wells. Technical, safety and cost considerations indicate that the required jet supply pressure can best be established by a downhole pressure intensifier. Key intensifier components are the check valve and plunger seals, which must prevent leakage of the high-pressure, high-temperature abrasive fluid (drilling mud). To achieve the required performance, novel ceramic seals are currently being developed. The check valve seal includes a tapered polymeric plug and ceramic stop acting against a ceramic seat.more » The ceramic plunger seal is a variant of the ''stepped-joint'' piston ring and is designed to minimize contact pressure and abrasive wear. Initial testing of these seals in the laboratory shows encouraging results; design refinement and further testing is in progress. 2 refs., 6 figs., 3 tabs.« less

A digital acquisition and elaboration system for nuclear fast pulse detection

NASA Astrophysics Data System (ADS)

Esposito, B.; Riva, M.; Marocco, D.; Kaschuck, Y.

2007-03-01

A new digital acquisition and elaboration system has been developed and assembled in ENEA-Frascati for the direct sampling of fast pulses from nuclear detectors such as scintillators and diamond detectors. The system is capable of performing the digital sampling of the pulses (200 MSamples/s, 14-bit) and the simultaneous (compressed) data transfer for further storage and software elaboration. The design (FPGA-based) is oriented to real-time applications and has been developed in order to allow acquisition with no loss of pulses and data storage for long-time intervals (tens of s at MHz pulse count rates) without the need of large on-board memory. A dedicated pulse analysis software, written in LabVIEWTM, performs the treatment of the acquired pulses, including pulse recognition, pile-up rejection, baseline removal, pulse shape particle separation and pulse height spectra analysis. The acquisition and pre-elaboration programs have been fully integrated with the analysis software.

Excited States of the divacancy in SiC

NASA Astrophysics Data System (ADS)

Bockstedte, Michel; Garratt, Thomas; Ivady, Viktor; Gali, Adam

2014-03-01

The divacancy in SiC - a technologically mature material that fulfills the necessary requirements for hosting defect based quantum computing - is a good candidate for implementing a solid state quantum bit. Its ground state is isovalent to the NV center in diamond as demonstrated by density functional theory (DFT). Furthermore, coherent manipulation of divacancy spins in SiC has been demonstrated. The similarities to NV might indicate that the same inter system crossing (ICS) from the high to the low spin state is responsible for its spin-dependent fluorescent signal. By DFT and a DFT-based multi-reference hamiltonian we analyze the excited state spectrum of the defects. In contrast to the current picture of the spin dynamics of the NV center, we predict that a static Jahn-Teller effect in the first excited triplet states governs an ICS both with the excited and ground state of the divacancy.

Coring device with a improved core sleeve and anti-gripping collar with a collective core catcher

DOE Office of Scientific and Technical Information (OSTI.GOV)

Story, A.L.; Filshtinsky, M.

1986-01-28

This patent describes an improved coring apparatus used in combination with a coring bit and drill string. This device consists of: an outer driving structure adapted to be connected at one end to the coring bit for cutting a core in a borehole, and at the other end to the lower end of the drill string in telescoping and co-rotatable manner therewith; an inner barrel disposed within the outer driving structure and including a lower end portion adjacent to the bit; first means supporting the inner barrel in spaced relationship to the outer driving structure while permitting rotation of themore » driving structure with respect to the inner barrel; a woven metal mesh sleeve mounted in surrounding relation on at least a portion of the exterior surface of the inner barrel; second means, connected to a free end of the sleeve opposite the leading portion of the sleeve, for maintaining the portion of the sleeve which surrounds the inner barrel in compression and to maintain an inside diameter greater than the outside diameter of the inner barrel of the portion of the sleeve surrounding the inner barrel while the portion of the sleeve positioned inside the inner barrel being in tension to grip and compress a core received within the sleeve and having an outside diameter less than the inside diameter of the inner barrel when in tension, wherein the second means is also for engaging the core when the means is drawn into the inner barrel, and third means positioned within the inner barrel and connected to the leading portion of the sleeve to draw the sleeve within the inner barrel and to apply tension to the portion of the sleeve within the barrel to encase and grip the core as it is cut.« less

Synchrotron x-ray spectroscopy of EuHN O3 aqueous solutions at high temperatures and pressures and Nb-bearing silicate melt phases coexisting with hydrothermal fluids using a modified hydrothermal diamond anvil cell and rail assembly

USGS Publications Warehouse

Mayanovic, Robert A.; Anderson, Alan J.; Bassett, William A.; Chou, I.-Ming

2007-01-01

A modified hydrothermal diamond anvil cell (HDAC) rail assembly has been constructed for making synchrotron x-ray absorption spectroscopy, x-ray fluorescence, and x-ray mapping measurements on fluids or solid phases in contact with hydrothermal fluids up to ???900??C and 700 MPa. The diamond anvils of the HDAC are modified by laser milling grooves or holes, for the reduction of attenuation of incident and fluorescent x rays and sample cavities. The modified HDAC rail assembly has flexibility in design for measurement of light elements at low concentrations or heavy elements at trace levels in the sample and the capability to probe minute individual phases of a multiphase fluid-based system using focused x-ray microbeam. The supporting rail allows for uniform translation of the HDAC, rotation and tilt stages, and a focusing mirror, which is used to illuminate the sample for visual observation using a microscope, relative to the direction of the incident x-ray beam. A structure study of Eu(III) aqua ion behavior in high-temperature aqueous solutions and a study of Nb partitioning and coordination in a silicate melt in contact with a hydrothermal fluid are described as applications utilizing the modified HDAC rail assembly. ?? 2007 American Institute of Physics.

A novel diamond micro-/nano-machining process for the generation of hierarchical micro-/nano-structures

NASA Astrophysics Data System (ADS)

Zhu, Zhiwei; To, Suet; Ehmann, Kornel F.; Xiao, Gaobo; Zhu, Wule

2016-03-01

A new mechanical micro-/nano-machining process that combines rotary spatial vibrations (RSV) of a diamond tool and the servo motions of the workpiece is proposed and applied for the generation of multi-tier hierarchical micro-/nano-structures. In the proposed micro-/nano-machining system, the servo motion, as the primary cutting motion generated by a slow-tool-servo, is adopted for the fine generation of the primary surfaces with complex shapes. The RSV, as the tertiary cutting operation, is superimposed on the secondary fundamental rotary cutting motion to construct secondary nano-structures on the primary surface. Since the RSV system generally works at much higher frequencies and motion resolution than the primary and secondary motions, it leads to an inherent hierarchical cutting architecture. To investigate the machining performance, complex micro-/nano-structures were generated and explored by both numerical simulations and actual cutting tests. Rotary vibrations of the diamond tool at a constant rotational distance offer an inherent constant cutting velocity, leading to the ability for the generation of homogeneous micro-/nano-structures with fixed amplitudes and frequencies of the vibrations, even over large-scale surfaces. Furthermore, by deliberately combining the non-resonant three-axial vibrations and the servo motion, the generation of a variety of micro-/nano-structures with complex shapes and with flexibly tunable feature sizes can be achieved.

Age of UHP metamorphism in the Western Mediterranean: Insight from rutile and minute zircon inclusions in a diamond-bearing garnet megacryst (Edough Massif, NE Algeria)

NASA Astrophysics Data System (ADS)

Bruguier, Olivier; Bosch, Delphine; Caby, Renaud; Vitale-Brovarone, Alberto; Fernandez, Laure; Hammor, Dalila; Laouar, Rabah; Ouabadi, Aziouz; Abdallah, Nachida; Mechati, Mehdi

2017-09-01

Diamond-bearing UHP metamorphic rocks witness for subduction of lithospheric slabs into the mantle and their return to shallow levels. In this study we present U-Pb and trace elements analyses of zircon and rutile inclusions from a diamond-bearing garnet megacryst collected in a mélange unit exposed on the northern margin of Africa (Edough Massif, NE Algeria). Large rutile crystals (up to 300 μm in size) analyzed in situ provide a U-Pb age of 32.4 ± 3.3 Ma interpreted as dating the prograde to peak subduction stage of the mafic protolith. Trace element analyses of minute zircons (≤30 μm) indicate that they formed in equilibrium with the garnet megacryst at a temperature of 740-810 °C, most likely during HP retrograde metamorphism. U-Pb analyses provide a significantly younger age of 20.7 ± 2.3 Ma attributed to exhumation of the UHP units. This study allows bracketing the age of UHP metamorphism in the Western Mediterranean Orogen to the Oligocene/early Miocene, thus unambiguously relating UHP metamorphism to the Alpine history. Exhumation of these UHP units is coeval with the counterclockwise rotation of the Corsica-Sardinia block and most likely resulted from subduction rollback that was driven by slab pull.

Experimental investigation of the abrasive crown dynamics in orbital atherectomy.

PubMed

Zheng, Yihao; Belmont, Barry; Shih, Albert J

2016-07-01

Orbital atherectomy is a catheter-based minimally invasive procedure to modify the plaque within atherosclerotic arteries using a diamond abrasive crown. This study was designed to investigate the crown motion and its corresponding contact force with the vessel. To this end, a transparent arterial tissue-mimicking phantom made of polyvinyl chloride was developed, a high-speed camera and image processing technique were utilized to visualize and quantitatively analyze the crown motion in the vessel phantom, and a piezoelectric dynamometer measured the forces on the phantom during the procedure. Observed under typical orbital atherectomy rotational speeds of 60,000, 90,000, and 120,000rpm in a 4.8mm caliber vessel phantom, the crown motion was a combination of high-frequency rotation at 1000, 1500, and 1660.4-1866.1Hz and low-frequency orbiting at 18, 38, and 40Hz, respectively. The measured forces were also composed of these high and low frequencies, matching well with the rotation of the eccentric crown and the associated orbital motion. The average peak force ranged from 0.1 to 0.4N at different rotational speeds. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

S-EMG signal compression based on domain transformation and spectral shape dynamic bit allocation

PubMed Central

2014-01-01

Background Surface electromyographic (S-EMG) signal processing has been emerging in the past few years due to its non-invasive assessment of muscle function and structure and because of the fast growing rate of digital technology which brings about new solutions and applications. Factors such as sampling rate, quantization word length, number of channels and experiment duration can lead to a potentially large volume of data. Efficient transmission and/or storage of S-EMG signals are actually a research issue. That is the aim of this work. Methods This paper presents an algorithm for the data compression of surface electromyographic (S-EMG) signals recorded during isometric contractions protocol and during dynamic experimental protocols such as the cycling activity. The proposed algorithm is based on discrete wavelet transform to proceed spectral decomposition and de-correlation, on a dynamic bit allocation procedure to code the wavelets transformed coefficients, and on an entropy coding to minimize the remaining redundancy and to pack all data. The bit allocation scheme is based on mathematical decreasing spectral shape models, which indicates a shorter digital word length to code high frequency wavelets transformed coefficients. Four bit allocation spectral shape methods were implemented and compared: decreasing exponential spectral shape, decreasing linear spectral shape, decreasing square-root spectral shape and rotated hyperbolic tangent spectral shape. Results The proposed method is demonstrated and evaluated for an isometric protocol and for a dynamic protocol using a real S-EMG signal data bank. Objective performance evaluations metrics are presented. In addition, comparisons with other encoders proposed in scientific literature are shown. Conclusions The decreasing bit allocation shape applied to the quantized wavelet coefficients combined with arithmetic coding results is an efficient procedure. The performance comparisons of the proposed S-EMG data compression algorithm with the established techniques found in scientific literature have shown promising results. PMID:24571620

Comparison of piezosurgery and conventional rotative instruments in direct sinus lifting.

PubMed

Delilbasi, Cagri; Gurler, Gokhan

2013-12-01

The purpose of this study was to compare the intraoperative and postoperative effects of Piezosurgery and conventional rotative instruments in direct sinus lifting procedure. Twenty-three patients requiring direct sinus lifting were enrolled. The osteotomy and sinus membrane elevation were performed either with Piezosurgery tips or rotative diamond burs and manual membrane elevators. Time elapsed between bony window opening and completion of membrane elevation (duration), incidence of membrane perforation, visibility of the operation site, postoperative pain, swelling, sleeping, eating, phonetics, daily routine, and missed work as well as patient's expectation before and experience after the operation were evaluated. There was no significant difference between Piezosurgery and conventional groups regarding incidence of membrane perforation, duration, and operation site visibility as well as patient's expectation before and experience after the operation (P > 0.05). However, there were significantly more pain and swelling in the conventional group compared with the Piezosurgery group (P ≤ 0.05). Sinus lifting procedure performed with Piezosurgery causes less pain and swelling postoperatively compared with conventional technique. Patients' daily life activities and experience about the operation are not affected from the surgical technique.

Oxidation and adduct formation of xenobiotics in a microfluidic electrochemical cell with boron doped diamond electrodes and an integrated passive gradient rotation mixer.

PubMed

van den Brink, Floris T G; Wigger, Tina; Ma, Liwei; Odijk, Mathieu; Olthuis, Wouter; Karst, Uwe; van den Berg, Albert

2016-10-05

Reactive xenobiotic metabolites and their adduct formation with biomolecules such as proteins are important to study as they can be detrimental to human health. Here, we present a microfluidic electrochemical cell with integrated micromixer to study phase I and phase II metabolism as well as protein adduct formation of xenobiotics in a purely instrumental approach. The newly developed microfluidic device enables both the generation of reactive metabolites through electrochemical oxidation and subsequent adduct formation with biomolecules in a chemical microreactor. This allows us to study the detoxification of reactive species with glutathione and to predict potential toxicity of xenobiotics as a result of protein modification. Efficient mixing in microfluidic systems is a slow process due to the typically laminar flow conditions in shallow channels. Therefore, a passive gradient rotation micromixer has been designed that is capable of mixing liquids efficiently in a 790 pL volume within tens of milliseconds. The mixing principle relies on turning the concentration gradient that is initially established by bringing together two streams of liquid, to take advantage of the short diffusion distances in the shallow microchannels of thin-layer flow cells. The mixer is located immediately downstream of the working electrode of an electrochemical cell with integrated boron doped diamond electrodes. In conjunction with mass spectrometry, the two microreactors integrated in a single device provide a powerful tool to study the metabolism and toxicity of xenobiotics, which was demonstrated by the investigation of the model compound 1-hydroxypyrene.

Dental preparation with sonic vs high-speed finishing: analysis of microleakage in bonded veneer restorations.

PubMed

Faus-Matoses, Ignacio; Solá-Ruiz, Fernanda

2014-02-01

To compare marginal microleakage in porcelain veneer restorations following dental finishing using two types of instruments to test the hypothesis that microleakage will be less when teeth are prepared with sonic oscillating burs than when prepared with high-speed rotating burs. Fifty-six extracted human maxillary central incisors were selected and divided randomly into two groups. Group 1 samples underwent dental finishing using high-speed rotating diamond burs, while group 2 used sonic oscillating diamond burs. Buccal chamfer preparation was carried out for both groups. Forty eight of the samples (24 per group) were restored using IPS Empress ceramic veneers. 2% methylene blue was used to evaluate microleakage at the tooth/composite veneer interface. Teeth were sectioned lengthwise into three parts and microleakage was measured at two points - cervical and incisal - on each section. Before bonding, four teeth per group underwent SEM examination. Evaluation of microleakage at the cervical dentin margin showed a value of 10.5% in group 1 and 6.6% in group 2, which was statistically significantly different (p < 0.05). Incisal microleakage was 1.3% for group 1 and 1.2% for group 2, which was not significantly different. SEM revealed different patterns of surface texture in both areas according to the instrument used. Group 1 exhibited parallel horizontal abrasion grooves with a milled effect and thick smear layers; group 2 showed abrasive erosion, discontinuous perpendicular depressions, and thin smear layers. Tooth preparations finished with sonic burs produced significantly less microleakage in the cervical dentin area of bonded veneer restorations. No differences were found in the incisal enamel area.

High-dimensional free-space optical communications based on orbital angular momentum coding

NASA Astrophysics Data System (ADS)

Zou, Li; Gu, Xiaofan; Wang, Le

2018-03-01

In this paper, we propose a high-dimensional free-space optical communication scheme using orbital angular momentum (OAM) coding. In the scheme, the transmitter encodes N-bits information by using a spatial light modulator to convert a Gaussian beam to a superposition mode of N OAM modes and a Gaussian mode; The receiver decodes the information through an OAM mode analyser which consists of a MZ interferometer with a rotating Dove prism, a photoelectric detector and a computer carrying out the fast Fourier transform. The scheme could realize a high-dimensional free-space optical communication, and decodes the information much fast and accurately. We have verified the feasibility of the scheme by exploiting 8 (4) OAM modes and a Gaussian mode to implement a 256-ary (16-ary) coding free-space optical communication to transmit a 256-gray-scale (16-gray-scale) picture. The results show that a zero bit error rate performance has been achieved.

Precoded spatial multiplexing MIMO system with spatial component interleaver.

PubMed

Gao, Xiang; Wu, Zhanji

In this paper, the performance of precoded bit-interleaved coded modulation (BICM) spatial multiplexing multiple-input multiple-output (MIMO) system with spatial component interleaver is investigated. For the ideal precoded spatial multiplexing MIMO system with spatial component interleaver based on singular value decomposition (SVD) of the MIMO channel, the average pairwise error probability (PEP) of coded bits is derived. Based on the PEP analysis, the optimum spatial Q-component interleaver design criterion is provided to achieve the minimum error probability. For the limited feedback precoded proposed scheme with linear zero forcing (ZF) receiver, in order to minimize a bound on the average probability of a symbol vector error, a novel effective signal-to-noise ratio (SNR)-based precoding matrix selection criterion and a simplified criterion are proposed. Based on the average mutual information (AMI)-maximization criterion, the optimal constellation rotation angles are investigated. Simulation results indicate that the optimized spatial multiplexing MIMO system with spatial component interleaver can achieve significant performance advantages compared to the conventional spatial multiplexing MIMO system.

Results from Testing of Two Rotary Percussive Drilling Systems

NASA Technical Reports Server (NTRS)

Kriechbaum, Kristopher; Brown, Kyle; Cady, Ian; von der Heydt, Max; Klein, Kerry; Kulczycki, Eric; Okon, Avi

2010-01-01

The developmental test program for the MSL (Mars Science Laboratory) rotary percussive drill examined the e ect of various drill input parameters on the drill pene- tration rate. Some of the input parameters tested were drill angle with respect to gravity and percussive impact energy. The suite of rocks tested ranged from a high strength basalt to soft Kaolinite clay. We developed a hole start routine to reduce high sideloads from bit walk. The ongoing development test program for the IMSAH (Integrated Mars Sample Acquisition and Handling) rotary percussive corer uses many of the same rocks as the MSL suite. An additional performance parameter is core integrity. The MSL development test drill and the IMSAH test drill use similar hardware to provide rotation and percussion. However, the MSL test drill uses external stabilizers, while the IMSAH test drill does not have external stabilization. In addition the IMSAH drill is a core drill, while the MSL drill uses a solid powdering bit. Results from the testing of these two related drilling systems is examined.

Lightweight Low Force Rotary Percussive Coring Tool for Planetary Applications

NASA Technical Reports Server (NTRS)

Hironaka, Ross; Stanley, Scott

2010-01-01

A prototype low-force rotary-percussive rock coring tool for use in acquiring samples for geological surveys in future planetary missions was developed. The coring tool could eventually enable a lightweight robotic system to operate from a relatively small (less than 200 kg) mobile or fixed platform to acquire and cache Mars or other planetary rock samples for eventual return to Earth for analysis. To gain insight needed to design an integrated coring tool, the coring ability of commercially available coring bits was evaluated for effectiveness of varying key parameters: weight-on-bit, rotation speed, percussive rate and force. Trade studies were performed for different methods of breaking a core at its base and for retaining the core in a sleeve to facilitate sample transfer. This led to a custom coring tool design which incorporated coring, core breakage, core retention, and core extraction functions. The coring tool was tested on several types of rock and demonstrated the overall feasibility of this approach for robotic rock sample acquisition.

Summary: High Temperature Downhole Motor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Raymond, David W.

2017-10-01

Directional drilling can be used to enable multi-lateral completions from a single well pad to improve well productivity and decrease environmental impact. Downhole rotation is typically developed with a motor in the Bottom Hole Assembly (BHA) that develops drilling power (speed and torque) necessary to drive rock reduction mechanisms (i.e., the bit) apart from the rotation developed by the surface rig. Historically, wellbore deviation has been introduced by a “bent-sub,” located in the BHA, that introduces a small angular deviation, typically less than 3 degrees, to allow the bit to drill off-axis with orientation of the BHA controlled at themore » surface. The development of a high temperature downhole motor would allow reliable use of bent subs for geothermal directional drilling. Sandia National Laboratories is pursuing the development of a high temperature motor that will operate on either drilling fluid (water-based mud) or compressed air to enable drilling high temperature, high strength, fractured rock. The project consists of designing a power section based upon geothermal drilling requirements; modeling and analysis of potential solutions; and design, development and testing of prototype hardware to validate the concept. Drilling costs contribute substantially to geothermal electricity production costs. The present development will result in more reliable access to deep, hot geothermal resources and allow preferential wellbore trajectories to be achieved. This will enable development of geothermal wells with multi-lateral completions resulting in improved geothermal resource recovery, decreased environmental impact and enhanced well construction economics.« less

Distortion of 3D SU8 photonic structures fabricated by four-beam holographic lithography withumbrella configuration.

PubMed

Zhu, Xuelian; Xu, Yongan; Yang, Shu

2007-12-10

We present a quantitative study of the distortion from a threeterm diamond-like structure fabricated in SU8 polymer by four-beam holographic lithography. In the study of the refraction effect, theory suggests that the lattice in SU8 should be elongated in the [111] direction but have no distortion in the (111) plane, and each triangular-like hole array in the (111) plane would rotate by ~30 degrees away from that in air. Our experiments agree with the prediction on the periodicity in the (111) plane and the rotation due to refraction effect, however, we find that the film shrinkage during lithographic process has nearly compensated the predicted elongation in the [111] direction. In study of photonic bandgap (PBG) properties of silicon photonic crystals templated by the SU8 structure, we find that the distortion has decreased quality of PBG.

Experimental quantum verification in the presence of temporally correlated noise

NASA Astrophysics Data System (ADS)

Mavadia, S.; Edmunds, C. L.; Hempel, C.; Ball, H.; Roy, F.; Stace, T. M.; Biercuk, M. J.

2018-02-01

Growth in the capabilities of quantum information hardware mandates access to techniques for performance verification that function under realistic laboratory conditions. Here we experimentally characterise the impact of common temporally correlated noise processes on both randomised benchmarking (RB) and gate-set tomography (GST). Our analysis highlights the role of sequence structure in enhancing or suppressing the sensitivity of quantum verification protocols to either slowly or rapidly varying noise, which we treat in the limiting cases of quasi-DC miscalibration and white noise power spectra. We perform experiments with a single trapped 171Yb+ ion-qubit and inject engineered noise (" separators="∝σ^ z ) to probe protocol performance. Experiments on RB validate predictions that measured fidelities over sequences are described by a gamma distribution varying between approximately Gaussian, and a broad, highly skewed distribution for rapidly and slowly varying noise, respectively. Similarly we find a strong gate set dependence of default experimental GST procedures in the presence of correlated errors, leading to significant deviations between estimated and calculated diamond distances in the presence of correlated σ^ z errors. Numerical simulations demonstrate that expansion of the gate set to include negative rotations can suppress these discrepancies and increase reported diamond distances by orders of magnitude for the same error processes. Similar effects do not occur for correlated σ^ x or σ^ y errors or depolarising noise processes, highlighting the impact of the critical interplay of selected gate set and the gauge optimisation process on the meaning of the reported diamond norm in correlated noise environments.

Large aperture freeform VIS telescope with smart alignment approach

NASA Astrophysics Data System (ADS)

Beier, Matthias; Fuhlrott, Wilko; Hartung, Johannes; Holota, Wolfgang; Gebhardt, Andreas; Risse, Stefan

2016-07-01

The development of smart alignment and integration strategies for imaging mirror systems to be used within astronomical instrumentation are especially important with regard to the increasing impact of non-rotationally symmetric optics. In the present work, well-known assembly approaches preferentially applied in the course of infrared instrumentation are transferred to visible applications and are verified during the integration of an anamorphic imaging telescope breadboard. The four mirror imaging system is based on a modular concept using mechanically fixed arrangements of each two freeform surfaces, generated by servo assisted diamond machining and corrected using Magnetorheological Finishing as a figuring and smoothing step. Surface testing include optical CGH interferometry as well as tactile profilometry and is conducted with respect to diamond milled fiducials at the mirror bodies. A strict compliance of surface referencing during all significant fabrication steps allow for an easy integration and direct measurement of the system's wave aberration after initial assembly. The achievable imaging performance, as well as influences of the tight tolerance budget and mid-spatial frequency errors, are discussed and experimentally evaluated.

Electric-field assisted spin torque nano-oscillator and binary frequency shift keying modulation

NASA Astrophysics Data System (ADS)

Zhang, Xiangli; Chen, Hao-Hsuan; Zhang, Zongzhi; Liu, Yaowen

2018-04-01

Electric-controlled magnetization precession introduces technologically relevant possibility for developing spin torque nano-oscillators (STNO) with potential applications in microwave emission. Using the perpendicularly magnetized magnetic tunnel junction (MTJ), we show that the magnetization oscillation frequency can be tuned by the co-action of electric field and spin polarized current. The dynamical phase diagram of MTJ-based STNO is analytically predicted through coordinate transformation from the laboratory frame to the rotation frame, by which the nonstationary out-of-plane magnetization precession process is therefore transformed into the stationary process in the rotation frame. Furthermore, using this STNO as a microwave source, we numerically demonstrate that the bit signal can be transmitted by a binary frequency shift keying (BFSK) modulation technique. The BFSK scheme shows good modulation features with no transient state.

A Low Noise, Microprocessor-Controlled, Internally Digitizing Rotating-Vane Electric Field Mill for Airborne Platforms

NASA Technical Reports Server (NTRS)

Bateman, M. G.; Stewart, M. F.; Blakeslee, R. J.; Podgorny, s. J.; Christian, H. J.; Mach, D. M.; Bailey, J. C.; Daskar, D.

2006-01-01

This paper reports on a new generation of aircraft-based rotating-vane style electric field mills designed and built at NASA's Marshall Spaceflight Center. The mills have individual microprocessors that digitize the electric field signal at the mill and respond to commands from the data system computer. The mills are very sensitive (1 V/m per bit), have a wide dynamic range (115 dB), and are very low noise (+/-1 LSB). Mounted on an aircraft, these mills can measure fields from +/-1 V/m to +/-500 kV/m. Once-per-second commanding from the data collection computer to each mill allows for precise timing and synchronization. The mills can also be commanded to execute a self-calibration in flight, which is done periodically to monitor the status and health of each mill.

Single-Mode WGM Resonators Fabricated by Diamond Turning

NASA Technical Reports Server (NTRS)

Grudinin, Ivan; Maleki, Lute; Savchenkov, Anatoliy; Matsko, Andrewy; Strekalov, Dmitry; Iltchenko, Vladimir

2008-01-01

A diamond turning process has made possible a significant advance in the art of whispering-gallery-mode (WGM) optical resonators. By use of this process, it is possible to fashion crystalline materials into WGM resonators that have ultrahigh resonance quality factors (high Q values), are compact (ranging in size from millimeters down to tens of microns), and support single electromagnetic modes. This development combines and extends the developments reported in "Few- Mode Whispering-Gallery-Mode Resonators" (NPO-41256), NASA Tech Briefs, Vol. 30, No. 1 (January 2006), page 16a and "Fabrication of Submillimeter Axisymmetric Optical Components" (NPO-42056), NASA Tech Briefs, Vol. 31, No. 5 (May 2007), page 10a. To recapitulate from the first cited prior article: A WGM resonator of this special type consists of a rod, made of a suitable transparent material, from which protrudes a thin circumferential belt of the same material. The belt is integral with the rest of the rod and acts as a circumferential waveguide. If the depth and width of the belt are made appropriately small, then the belt acts as though it were the core of a single-mode optical fiber: the belt and the rod material adjacent to it support a single, circumferentially propagating mode or family of modes. To recapitulate from the second cited prior article: A major step in the fabrication of a WGM resonator of this special type is diamond turning or computer numerically controlled machining of a rod of a suitable transparent crystalline material on an ultrahigh-precision lathe. During the rotation of a spindle in which the rod is mounted, a diamond tool is used to cut the rod. A computer program is used to control stepping motors that move the diamond tool, thereby controlling the shape cut by the tool. Because the shape can be controlled via software, it is possible to choose a shape designed to optimize a resonator spectrum, including, if desired, to limit the resonator to supporting a single mode. After diamond turning, a resonator can be polished to increase its Q. By virtue of its largely automated, computer-controlled nature, the process is suitable for mass production of nominally identical single-mode WGM resonators. In a demonstration of the capabilities afforded by this development, a number of WGM resonators of various designs were fabricated side by side on the surface of a single CaF2 rod (see figure).

Research on the processing technology of elongated holes based on rotary ultrasonic drilling

NASA Astrophysics Data System (ADS)

Tong, Yi; Chen, Jianhua; Sun, Lipeng; Yu, Xin; Wang, Xin

2014-08-01

The optical glass is hard, brittle and difficult to process. Based on the method of rotating ultrasonic drilling, the study of single factor on drilling elongated holes was made in optical glass. The processing equipment was DAMA ultrasonic machine, and the machining tools were electroplated with diamond. Through the detection and analysis on the processing quality and surface roughness, the process parameters (the spindle speed, amplitude, feed rate) of rotary ultrasonic drilling were researched, and the influence of processing parameters on surface roughness was obtained, which will provide reference and basis for the actual processing.

A parallel VLSI architecture for a digital filter using a number theoretic transform

NASA Technical Reports Server (NTRS)

Truong, T. K.; Reed, I. S.; Yeh, C. S.; Shao, H. M.

1983-01-01

The advantages of a very large scalee integration (VLSI) architecture for implementing a digital filter using fermat number transforms (FNT) are the following: It requires no multiplication. Only additions and bit rotations are needed. It alleviates the usual dynamic range limitation for long sequence FNT's. It utilizes the FNT and inverse FNT circuits 100% of the time. The lengths of the input data and filter sequences can be arbitraty and different. It is regular, simple, and expandable, and as a consequence suitable for VLSI implementation.

Nano-inclusions in diamond: Evidence of diamond genesis

NASA Astrophysics Data System (ADS)

Wirth, R.

2015-12-01

The use of Focused Ion Beam technology (FIB) for TEM sample preparation introduced approximately 15 years ago revolutionized the application of TEM in Geosciences. For the first time, FIB enabled cutting samples for TEM use from exactly the location we are interested in. Applied to diamond investigation, this technique revealed the presence of nanometre-sized inclusions in diamond that have been simply unknown before. Nanoinclusions in diamond from different location and origin such as diamonds from the Lower and Upper Mantle, metamorphic diamonds (Kazakhstan, Erzgebirge, Bohemia), diamonds from ophiolites (Tibet, Mongolia, Xinjiang, Ural Mountains), diamonds from igneous rocks (Hawaii, Kamchatka) and impact diamonds (Popigai Crater, Siberia) have been investigated during the last 15 years. The major conclusion of all these TEM studies is, that the nanoinclusions, their phases and phase composition together with the micro- and nanostructure evidence the origin of diamond and genesis of diamond. We can discriminate Five different mechanisms of diamond genesis in nature are observed: Diamond crystallized from a high-density fluid (Upper mantle and metamorphic diamond). Diamond crystallized from carbonatitic melt (Lower mantle diamond). Diamond precipitates from a metal alloy melt (Diamond from ophiolites). Diamond crystallized by gas phase condensation or chemical vapour condensation (CVD) (Lavas from Kamchatka, xenoliths in Hawaiian lavas). Direct transformation of graphite into diamond.

A Power-Efficient Bio-Potential Acquisition Device with DS-MDE Sensors for Long-Term Healthcare Monitoring Applications

PubMed Central

Chang, Chia-Lin; Chang, Chih-Wei; Huang, Hong-Yi; Hsu, Chen-Ming; Huang, Chia-Hsuan; Chiou, Jin-Chern; Luo, Ching-Hsing

2010-01-01

This work describes a power-efficient bio-potential acquisition device for long-term healthcare applications that is implemented using novel microelectromechanical dry electrodes (MDE) and a low power bio-potential processing chip. Using micromachining technology, an attempt is also made to enhance the sensing reliability and stability by fabricating a diamond-shaped MDE (DS-MDE) that has a satisfactory self-stability capability and superior electric conductivity when attached onto skin without any extra skin tissue injury technology. To acquire differential bio-potentials such as ECG signals, the proposed processing chip fabricated in a standard CMOS process has a high common mode rejection ratio (C.M.R.R.) differential amplifier and a 12-bit analog-to-digital converter (ADC). Use of the proposed system and integrate simple peripheral commercial devices can obtain the ECG signal efficiently without additional skin tissue injury and ensure continuous monitoring more than 70 hours with a 400 mAh battery. PMID:22399907

A power-efficient bio-potential acquisition device with DS-MDE sensors for long-term healthcare monitoring applications.

PubMed

Chang, Chia-Lin; Chang, Chih-Wei; Huang, Hong-Yi; Hsu, Chen-Ming; Huang, Chia-Hsuan; Chiou, Jin-Chern; Luo, Ching-Hsing

2010-01-01

This work describes a power-efficient bio-potential acquisition device for long-term healthcare applications that is implemented using novel microelectromechanical dry electrodes (MDE) and a low power bio-potential processing chip. Using micromachining technology, an attempt is also made to enhance the sensing reliability and stability by fabricating a diamond-shaped MDE (DS-MDE) that has a satisfactory self-stability capability and superior electric conductivity when attached onto skin without any extra skin tissue injury technology. To acquire differential bio-potentials such as ECG signals, the proposed processing chip fabricated in a standard CMOS process has a high common mode rejection ratio (C.M.R.R.) differential amplifier and a 12-bit analog-to-digital converter (ADC). Use of the proposed system and integrate simple peripheral commercial devices can obtain the ECG signal efficiently without additional skin tissue injury and ensure continuous monitoring more than 70 hours with a 400 mAh battery.

Industrial diamond

USGS Publications Warehouse

Olson, D.W.

2001-01-01

An overview of the industrial diamond industry is provided. More than 90 percent of the industrial diamond consumed in the U.S. and the rest of the world is manufactured diamond. Ireland, Japan, Russia, and the U.S. produce 75 percent of the global industrial diamond output. In 2000, the U.S. was the largest market for industrial diamond. Industrial diamond applications, prices for industrial diamonds, imports and exports of industrial diamonds, the National Defense Stockpile of industrial diamonds, and the outlook for the industrial diamond market are discussed.

Development of a Piezoelectric Rotary Hammer Drill

NASA Technical Reports Server (NTRS)

Domm, Lukas N.

2011-01-01

The Piezoelectric Rotary Hammer Drill is designed to core through rock using a combination of rotation and high frequency hammering powered by a single piezoelectric actuator. It is designed as a low axial preload, low mass, and low power device for sample acquisition on future missions to extraterrestrial bodies. The purpose of this internship is to develop and test a prototype of the Piezoelectric Rotary Hammer Drill in order to verify the use of a horn with helical or angled cuts as a hammering and torque inducing mechanism. Through an iterative design process using models in ANSYS Finite Element software and a Mason's Equivalent Circuit model in MATLAB, a horn design was chosen for fabrication based on the predicted horn tip motion, electromechanical coupling, and neutral plane location. The design was then machined and a test bed assembled. The completed prototype has proven that a single piezoelectric actuator can be used to produce both rotation and hammering in a drill string through the use of a torque inducing horn. Final data results include bit rotation produced versus input power, and best drilling rate achieved with the prototype.

Microstructural evolution of diamond growth during HFCVD

NASA Technical Reports Server (NTRS)

Singh, J.

1994-01-01

High resolution transmission electron microscopy (HRTEM) was used to study the nucleation and growth mechanism of diamond by hot filament chemical vapor deposition (HFCVD) process. A novel technique has shown a direct evidence for the formation of the diamond-like carbon layer 8-14 nm thick in which small diamond micro-crystallites were embedded. These diamond micro-crystallites were formed as a result of transformation of diamond-like carbon into diamond. The diamond micro-crystallites present in the amorphous diamond-like carbon layer provided nucleation sites for diamond growth. Large diamond crystallites were observed to grow from these micro-crystallites. The mechanism of diamond growth will be presented based on experimental findings.

Development of an Ultra-Light Multipurpose Drill and Tooling for the Transportable Array in Alaska

NASA Astrophysics Data System (ADS)

Coyle, B. J.; Lundgren, M.; Busby, R. W.

2014-12-01

Over the next four years the EarthScope Transportable Array (TA) will install approximately 250 to 275 broadband seismic stations in Alaska and Western Canada. The station plans build on recent developments in posthole broadband seismometer design and call for sensors to be installed in boreholes 7 inches diameter, from 1 to 5 meters deep. These boreholes will be lined with PVC or steel casing, grouted in place. The proposed station locations are in a grid-like pattern with a nominal spacing of 85 km. Since most of these locations will only be accessible by helicopter, it was necessary to develop an ultra-light drilling system that could be transported to site in one sling load by a high performance light helicopter (i.e. AS350B2 or Bell 407) and still be able to drill the variety of ground conditions we expect to encounter. In the past year we have developed a working prototype, gasoline-hydraulic drill rig that can be configured to run auger, diamond core or DTH tools, and weighs <1,300 lbs, including tooling. We have successfully drilled over 30 boreholes with this drill, including 12 for TA installations in Alaska and 13 at the Piñon Flat Observatory for testing sensor performance and placement techniques. Our drilling solution comprises: - Hydraulic system using a variable flow pump with on-demand load sensing valves to reduce the engine size needed and to cut down on heat build-up; - Rotation head mounting system on the travelling block to enable quick change of drilling tools; - Low speed, high torque rotation head for the auger, and an anchoring system that enables us to apply up to 5,000 lbs downforce for augering in permafrost; - Custom DTH that can run on low air pressure and air flow, yet is still robust enough to drill a 7 inch hole 2.5 meters through solid rock; - One-trip casing advance drilling with the DTH, steel casing is loaded at the start of drilling and follows the drill bit down; - Grout-through bottom caps for sealing the borehole casing and cementing it in place. Our next step is to build a dedicated DTH drilling system that will be light enough to mobilize to sites in one helicopter sling, including an air compressor. This rig is currently on the drawing board and we expect to build it this winter for field testing in the spring.

Earthshots: Satellite images of environmental change – Selkirk Island, Chile

USGS Publications Warehouse

,

2013-01-01

How did these Karman vortices develop? On that day, the wind was carrying northward a layer of stratocumulus clouds (flat-bottomed puffballs). The mile-high island caused this cloud layer to slow about the island, while remaining fast farther out on either side. So on each “wing,” left and right, the air started rotating toward the inside—clockwise on the left, counter-clockwise on the right. The rotational momentum made each side swirl in on itself. The whorl-cores were clear because the swirling pulled dry, clear air (from above or below) into the wet layer, a bit like the funnel formed when you stir up a pitcher of orange juice. These clear, spinning pockets trailed off down the “street” from the island like soap bubbles from a toy wand—drifting downwind, weakening, filling with clouds, and breaking up.

An Ultra-wideband and Polarization-independent Metasurface for RCS Reduction

PubMed Central

Su, Pei; Zhao, Yongjiu; Jia, Shengli; Shi, Wenwen; Wang, Hongli

2016-01-01

In this paper, an ultra-wideband and polarization-independent metasurface for radar cross section (RCS) reduction is proposed. The unit cell of the metasurface operates in a linear cross-polarization scheme in a broad band. The phase and amplitude of cross-polarized reflection can be separately controlled by its geometry and rotation angle. Based on the diffuse reflection theory, a 3-bit coding metasurface is designed to reduce the RCS in an ultra-wide band. The wideband property of the metasurface benefits from the wideband cross polarization conversion and flexible phase modulation. In addition, the polarization-independent feature of the metasurface is achieved by tailoring the rotation angle of each element. Both the simulated and measured results demonstrate that the proposed metasurface can reduce the RCS significantly in an ultra-wide frequency band for both normal and oblique incidences, which makes it promising in the applications such as electromagnetic cloaking. PMID:26864084

All-optical clocked flip-flops and random access memory cells using the nonlinear polarization rotation effect of low-polarization-dependent semiconductor optical amplifiers

NASA Astrophysics Data System (ADS)

Wang, Yongjun; Liu, Xinyu; Tian, Qinghua; Wang, Lina; Xin, Xiangjun

2018-03-01

Basic configurations of various all-optical clocked flip-flops (FFs) and optical random access memory (RAM) based on the nonlinear polarization rotation (NPR) effect of low-polarization-dependent semiconductor optical amplifiers (SOA) are proposed. As the constituent elements, all-optical logic gates and all-optical SR latches are constructed by taking advantage of the SOA's NPR switch. Different all-optical FFs (AOFFs), including SR-, D-, T-, and JK-types as well as an optical RAM cell were obtained by the combination of the proposed all-optical SR latches and logic gates. The effectiveness of the proposed schemes were verified by simulation results and demonstrated by a D-FF and 1-bit RAM cell experimental system. The proposed all-optical clocked FFs and RAM cell are significant to all-optical signal processing.

An Ultra-wideband and Polarization-independent Metasurface for RCS Reduction.

PubMed

Su, Pei; Zhao, Yongjiu; Jia, Shengli; Shi, Wenwen; Wang, Hongli

2016-02-11

In this paper, an ultra-wideband and polarization-independent metasurface for radar cross section (RCS) reduction is proposed. The unit cell of the metasurface operates in a linear cross-polarization scheme in a broad band. The phase and amplitude of cross-polarized reflection can be separately controlled by its geometry and rotation angle. Based on the diffuse reflection theory, a 3-bit coding metasurface is designed to reduce the RCS in an ultra-wide band. The wideband property of the metasurface benefits from the wideband cross polarization conversion and flexible phase modulation. In addition, the polarization-independent feature of the metasurface is achieved by tailoring the rotation angle of each element. Both the simulated and measured results demonstrate that the proposed metasurface can reduce the RCS significantly in an ultra-wide frequency band for both normal and oblique incidences, which makes it promising in the applications such as electromagnetic cloaking.

Synchronization trigger control system for flow visualization

NASA Technical Reports Server (NTRS)

Chun, K. S.

1987-01-01

The use of cinematography or holographic interferometry for dynamic flow visualization in an internal combustion engine requires a control device that globally synchronizes camera and light source timing at a predefined shaft encoder angle. The device is capable of 0.35 deg resolution for rotational speeds of up to 73 240 rpm. This was achieved by implementing the shaft encoder signal addressed look-up table (LUT) and appropriate latches. The developed digital signal processing technique achieves 25 nsec of high speed triggering angle detection by using direct parallel bit comparison of the shaft encoder digital code with a simulated angle reference code, instead of using angle value comparison which involves more complicated computation steps. In order to establish synchronization to an AC reference signal whose magnitude is variant with the rotating speed, a dynamic peak followup synchronization technique has been devised. This method scrutinizes the reference signal and provides the right timing within 40 nsec. Two application examples are described.

Detection of Rotational Sequences for Global Oscillation Modes inside the Sun

NASA Technical Reports Server (NTRS)

Wolff, Charles L.; Niemann, Hasso B. (Technical Monitor)

2002-01-01

A very simple mathematical sequence is detected in a half century of thermal radio flux from the Sun. Since the only known physical cause of the sequence is global oscillations trapped in the nonconvecting solar interior, g-modes and probably r-modes are active. If so, their rotation frequencies are detected and some previously reported difference frequencies are confirmed with high confidence. All angular harmonics for 2 less than or = l less than or = 7 are detected as well as some others up to the limit l less than or = 14 resolvable by the observations (a Fourier spectrum of the 10.7 cm flux time series). The mean sidereal rotation of the nonconvecting interior is 428.2 nHz as averaged by g-modes and 429.8 nHz by the r-modes, indicating that g-mode energy is a bit more centrally concentrated. Helioseismology measures such rotation rates near 0.36R (R = solar radius), so the global modes would have about half their kinetic energy above and below that level. This, and the known log(r) energy dependence of most modes implies that these oscillations are significantly reflected near 0.18R, the same level at which sound speed measurements display a maximum departure from theoretical models.

Portable sequential multicolor thermal imager based on a MCT 384 x 288 focal plane array

NASA Astrophysics Data System (ADS)

Breiter, Rainer; Cabanski, Wolfgang A.; Mauk, Karl-Heinz; Rode, Werner; Ziegler, Johann

2001-10-01

AIM has developed a sequential multicolor thermal imager to provide customers with a test system to realize real-time spectral selective thermal imaging. In contrast to existing PC based laboratory units, the system is miniaturized with integrated signal processing like non-uniformity correction and post processing functions such as image subtraction of different colors to allow field tests in military applications like detection of missile plumes or camouflaged targets as well as commercial applications like detection of chemical agents, pollution control, etc. The detection module used is a 384 X 288 mercury cadmium telluride (MCT) focal plane array (FPA) available in the mid wave (MWIR) or long wave spectral band LWIR). A compact command and control electronics (CCE) provides clock and voltage supply for the detector as well as 14 bit deep digital conversion of the analog detector output. A continuous rotating wheel with four facets for filters provides spectral selectivity. The customer can choose between various types of filter characteristics, e.g. a 4.2 micrometer bandpass filter for CO2 detection in the MWIR band. The rotating wheel can be synchronized to an external source giving the rotation speed, typical 25 l/s. A position sensor generates the four frame start signals for synchronous operation of the detector -- 100 Hz framerate for the four frames per rotation. The rotating wheel is exchangeable for different configurations and also plates for a microscanner operation to improve geometrical resolution are available instead of a multicolor operation. AIM's programmable MVIP image processing unit is used for signal processing like non- uniformity correction and controlling the detector parameters. The MVIP allows to output the four subsequent images as four quarters of the video screen to prior to any observation task set the integration time for each color individually for comparable performance in each spectral color and after that also to determine separate NUC coefficients for each filter position. This procedure allows to really evaluate the pay off of spectral selectivity in the IR. The display part of the MVIP allows linear look up tables (LUT) for dynamic reduction as well as histogram equalization for automatic LUT optimization. Parallel to the video output a digital interface is provided for digital recording of the 14 bit corrected detector data. The architecture of the thermal imager with its components is presented in this paper together with some aspects on multicolor thermal imaging.

Lower pressure synthesis of diamond material

DOEpatents

Lueking, Angela; Gutierrez, Humberto; Narayanan, Deepa; Burgess Clifford, Caroline E.; Jain, Puja

2010-07-13

Methods of synthesizing a diamond material, particularly nanocrystalline diamond, diamond-like carbon and bucky diamond are provided. In particular embodiments, a composition including a carbon source, such as coal, is subjected to addition of energy, such as high energy reactive milling, producing a milling product enriched in hydrogenated tetrahedral amorphous diamond-like carbon compared to the coal. A milling product is treated with heat, acid and/or base to produce nanocrystalline diamond and/or crystalline diamond-like carbon. Energy is added to produced crystalline diamond-like carbon in particular embodiments to produce bucky diamonds.

A study of electro-osmosis as applied to drilling engineering

NASA Astrophysics Data System (ADS)

Hariharan, Peringandoor Raman

In the present research project. the application of the process of electro-osmosis has been extended to a variety of rocks during the drilling operation. Electro-osmosis has been utilized extensively to examine its influence in reducing (i) bit balling, (ii) coefficient of friction between rock and metal and (iii) bit/tool wear. An attempt has been made to extend the envelope of confidence in which electro-osmosis was found to be operating satisfactorily. For all the above cases the current requirements during electro-osmosis were identified and were recorded. A novel test method providing repeatable results has been developed to study the problem of bit balling in the laboratory through the design of a special metallic bob simulating the drill bit. A numerical parameter described as the Degree-of-Balling (DOB) defined by the amount of cuttings stuck per unit volume of rock cut for the same duration of time is being proposed as a means to quantitatively describe the balling process in the laboratory. Five different types of shales (Pierre I & II, Catoosa, Mancos and Wellington) were compared and evaluated for balling characteristics and to determine the best conditions for reducing bit balling with electro-osmosis in a variety of drilling fluids including fresh water, polymer solutions and field type drilling fluids. Through the design, fabrication and performing of experiments conducted with a model Bottom Hole Assembly (BHA). the feasibility of maintaining the drill bit separately at a negative potential and causing the current to flow through the rock back into the string through a near bit stabilizer has been demonstrated. Experiments conducted with this self contained arrangement for the application of electro-osmosis have demonstrated a substantial decrease in balling and increase in the rate of penetration (ROP) while drilling with both a roller cone and PDC microbit (1-1/4" dia.) in Pierre I and Wellington shales. It is believed that the results obtained from the model BHA will aid in scaling up to a full-scale prototype BHA for possible application in the field. Experiments conducted with electro-osmosis in a simulated drill string under loaded conditions have clearly demonstrated that the coefficient of friction (mu) can be reduced at the interface of a rotating cylinder (simulating the drill-pipe) and a rock (usually a type of shale), through electro-osmosis. Studies examined the influence of many variables such as drilling fluid, rock type, and current on mu. The need for the correct estimation of mu is for reliable correlation between values obtained in the laboratory with those observed in the field. The knowledge of the coefficient of friction (mu) is an important requirement for drill string design and well trajectory planning. The use of electro-osmosis in reducing bit/tool wear through experiments in various rocks utilizing a specially designed steel bob simulating the drill bit has clearly indicated a decreased average tool wear, varying from 35% in Pierre I shale up to 57% in sandstone when used with the tool maintained at a cathodic DC potential. (Abstract shortened by UMI.)

Anisotropic diamond etching through thermochemical reaction between Ni and diamond in high-temperature water vapour.

PubMed

Nagai, Masatsugu; Nakanishi, Kazuhiro; Takahashi, Hiraku; Kato, Hiromitsu; Makino, Toshiharu; Yamasaki, Satoshi; Matsumoto, Tsubasa; Inokuma, Takao; Tokuda, Norio

2018-04-27

Diamond possesses excellent physical and electronic properties, and thus various applications that use diamond are under development. Additionally, the control of diamond geometry by etching technique is essential for such applications. However, conventional wet processes used for etching other materials are ineffective for diamond. Moreover, plasma processes currently employed for diamond etching are not selective, and plasma-induced damage to diamond deteriorates the device-performances. Here, we report a non-plasma etching process for single crystal diamond using thermochemical reaction between Ni and diamond in high-temperature water vapour. Diamond under Ni films was selectively etched, with no etching at other locations. A diamond-etching rate of approximately 8.7 μm/min (1000 °C) was successfully achieved. To the best of our knowledge, this rate is considerably greater than those reported so far for other diamond-etching processes, including plasma processes. The anisotropy observed for this diamond etching was considerably similar to that observed for Si etching using KOH.

LDFT-based watermarking resilient to local desynchronization attacks.

PubMed

Tian, Huawei; Zhao, Yao; Ni, Rongrong; Qin, Lunming; Li, Xuelong

2013-12-01

Up to now, a watermarking scheme that is robust against desynchronization attacks (DAs) is still a grand challenge. Most image watermarking resynchronization schemes in literature can survive individual global DAs (e.g., rotation, scaling, translation, and other affine transforms), but few are resilient to challenging cropping and local DAs. The main reason is that robust features for watermark synchronization are only globally invariable rather than locally invariable. In this paper, we present a blind image watermarking resynchronization scheme against local transform attacks. First, we propose a new feature transform named local daisy feature transform (LDFT), which is not only globally but also locally invariable. Then, the binary space partitioning (BSP) tree is used to partition the geometrically invariant LDFT space. In the BSP tree, the location of each pixel is fixed under global transform, local transform, and cropping. Lastly, the watermarking sequence is embedded bit by bit into each leaf node of the BSP tree by using the logarithmic quantization index modulation watermarking embedding method. Simulation results show that the proposed watermarking scheme can survive numerous kinds of distortions, including common image-processing attacks, local and global DAs, and noninvertible cropping.

Structure optimization of a micro drill bit with nonlinear constraints considering the effects of eccentricity, gyroscopic moments, lateral and torsional vibrations

NASA Astrophysics Data System (ADS)

Nguyen, Danh-Tuyen; Hoang, Tien-Dat; Lee, An-Chen

2017-10-01

A micro drill structure was optimized to give minimum lateral displacement at its drill tip, which plays an extremely important role on the quality of drilled holes. A drilling system includes a spindle, chuck and micro drill bit, which are modeled as rotating Timoshenko beam elements considering axial drilling force, torque, gyroscopic moments, eccentricity and bearing reaction force. Based on our previous work, the lateral vibration at the drill tip is evaluated. It is treated as an objective function in the optimization problem. Design variables are diameter and lengths of cylindrical and conical parts of the micro drill, along with nonlinear constraints on its mass and mass center location. Results showed that the lateral vibration was reduced by 15.83 % at a cutting speed of 70000 rpm as compared to that for a commercial UNION drill. Among the design variables, we found that the length of the conical part connecting to the drill shank plays the most important factor on the lateral vibration during cutting process.

Diamond fiber field emitters

DOEpatents

Blanchet-Fincher, Graciela B.; Coates, Don M.; Devlin, David J.; Eaton, David F.; Silzars, Aris K.; Valone, Steven M.

1996-01-01

A field emission electron emitter comprising an electrode formed of at least one diamond, diamond-like carbon or glassy carbon composite fiber, said composite fiber having a non-diamond core and a diamond, diamond-like carbon or glassy carbon coating on said non-diamond core, and electronic devices employing such a field emission electron emitter.

Investigations on diamond nanostructuring of different morphologies by the reactive-ion etching process and their potential applications.

PubMed

Kunuku, Srinivasu; Sankaran, Kamatchi Jothiramalingam; Tsai, Cheng-Yen; Chang, Wen-Hao; Tai, Nyan-Hwa; Leou, Keh-Chyang; Lin, I-Nan

2013-08-14

We report the systematic studies on the fabrication of aligned, uniform, and highly dense diamond nanostructures from diamond films of various granular structures. Self-assembled Au nanodots are used as a mask in the self-biased reactive-ion etching (RIE) process, using an O2/CF4 process plasma. The morphology of diamond nanostructures is a close function of the initial phase composition of diamond. Cone-shaped and tip-shaped diamond nanostructures result for microcrystalline diamond (MCD) and nanocrystalline diamond (NCD) films, whereas pillarlike and grasslike diamond nanostructures are obtained for Ar-plasma-based and N2-plasma-based ultrananocrystalline diamond (UNCD) films, respectively. While the nitrogen-incorporated UNCD (N-UNCD) nanograss shows the most-superior electron-field-emission properties, the NCD nanotips exhibit the best photoluminescence properties, viz, different applications need different morphology of diamond nanostructures to optimize the respective characteristics. The optimum diamond nanostructure can be achieved by proper choice of granular structure of the initial diamond film. The etching mechanism is explained by in situ observation of optical emission spectrum of RIE plasma. The preferential etching of sp(2)-bonded carbon contained in the diamond films is the prime factor, which forms the unique diamond nanostructures from each type of diamond films. However, the excited oxygen atoms (O*) are the main etching species of diamond film.

Lateral overgrowth of diamond film on stripes patterned Ir/HPHT-diamond substrate

NASA Astrophysics Data System (ADS)

Wang, Yan-Feng; Chang, Xiaohui; Liu, Zhangcheng; Liu, Zongchen; Fu, Jiao; Zhao, Dan; Shao, Guoqing; Wang, Juan; Zhang, Shaopeng; Liang, Yan; Zhu, Tianfei; Wang, Wei; Wang, Hong-Xing

2018-05-01

Epitaxial lateral overgrowth (ELO) of diamond films on patterned Ir/(0 0 1)HPHT-diamond substrates have been carried out by microwave plasma CVD system. Ir/(0 0 1)HPHT-diamond substrates are fabricated by photolithographic and magnetron sputtering technique. The morphology of the as grown ELO diamond film is characterized by optical microscopy and scanning electronic microscopy. The quality and stress of the ELO diamond film are investigated by surface etching pit density and micro-Raman spectroscopy. Two ultraviolet photodetectors are fabricated on ELO diamond area and non-ELO diamond area prepared on same substrate, and that one on ELO diamond area indicates better photoelectric properties. All results indicate quality of ELO diamond film is improved.

Diamond Synthesis Employing Nanoparticle Seeds

NASA Technical Reports Server (NTRS)

Uppireddi, Kishore (Inventor); Morell, Gerardo (Inventor); Weiner, Brad R. (Inventor)

2014-01-01

Iron nanoparticles were employed to induce the synthesis of diamond on molybdenum, silicon, and quartz substrates. Diamond films were grown using conventional conditions for diamond synthesis by hot filament chemical vapor deposition, except that dispersed iron oxide nanoparticles replaced the seeding. This approach to diamond induction can be combined with dip pen nanolithography for the selective deposition of diamond and diamond patterning while avoiding surface damage associated to diamond-seeding methods.

Diamond tool machining of materials which react with diamond

DOEpatents

Lundin, Ralph L.; Stewart, Delbert D.; Evans, Christopher J.

1992-01-01

Apparatus for the diamond machining of materials which detrimentally react with diamond cutting tools in which the cutting tool and the workpiece are chilled to very low temperatures. This chilling halts or retards the chemical reaction between the workpiece and the diamond cutting tool so that wear rates of the diamond tool on previously detrimental materials are comparable with the diamond turning of materials which do not react with diamond.

The Effects of Operational Parameters on a Mono-wire Cutting System: Efficiency in Marble Processing

NASA Astrophysics Data System (ADS)

Yilmazkaya, Emre; Ozcelik, Yilmaz

2016-02-01

Mono-wire block cutting machines that cut with a diamond wire can be used for squaring natural stone blocks and the slab-cutting process. The efficient use of these machines reduces operating costs by ensuring less diamond wire wear and longer wire life at high speeds. The high investment costs of these machines will lead to their efficient use and reduce production costs by increasing plant efficiency. Therefore, there is a need to investigate the cutting performance parameters of mono-wire cutting machines in terms of rock properties and operating parameters. This study aims to investigate the effects of the wire rotational speed (peripheral speed) and wire descending speed (cutting speed), which are the operating parameters of a mono-wire cutting machine, on unit wear and unit energy, which are the performance parameters in mono-wire cutting. By using the obtained results, cuttability charts for each natural stone were created on the basis of unit wear and unit energy values, cutting optimizations were performed, and the relationships between some physical and mechanical properties of rocks and the optimum cutting parameters obtained as a result of the optimization were investigated.

Parabens abatement from surface waters by electrochemical advanced oxidation with boron doped diamond anodes.

PubMed

Domínguez, Joaquín R; Muñoz-Peña, Maria J; González, Teresa; Palo, Patricia; Cuerda-Correa, Eduardo M

2016-10-01

The removal efficiency of four commonly-used parabens by electrochemical advanced oxidation with boron-doped diamond anodes in two different aqueous matrices, namely ultrapure water and surface water from the Guadiana River, has been analyzed. Response surface methodology and a factorial, composite, central, orthogonal, and rotatable (FCCOR) statistical design of experiments have been used to optimize the process. The experimental results clearly show that the initial concentration of pollutants is the factor that influences the removal efficiency in a more remarkable manner in both aqueous matrices. As a rule, as the initial concentration of parabens increases, the removal efficiency decreases. The current density also affects the removal efficiency in a statistically significant manner in both aqueous matrices. In the water river aqueous matrix, a noticeable synergistic effect on the removal efficiency has been observed, probably due to the presence of chloride ions that increase the conductivity of the solution and contribute to the generation of strong secondary oxidant species such as chlorine or HClO/ClO - . The use of a statistical design of experiments made it possible to determine the optimal conditions necessary to achieve total removal of the four parabens in ultrapure and river water aqueous matrices.

All diamond self-aligned thin film transistor

DOEpatents

Gerbi, Jennifer [Champaign, IL

2008-07-01

A substantially all diamond transistor with an electrically insulating substrate, an electrically conductive diamond layer on the substrate, and a source and a drain contact on the electrically conductive diamond layer. An electrically insulating diamond layer is in contact with the electrically conductive diamond layer, and a gate contact is on the electrically insulating diamond layer. The diamond layers may be homoepitaxial, polycrystalline, nanocrystalline or ultrananocrystalline in various combinations.A method of making a substantially all diamond self-aligned gate transistor is disclosed in which seeding and patterning can be avoided or minimized, if desired.

Almost all quantum channels are equidistant

NASA Astrophysics Data System (ADS)

Nechita, Ion; Puchała, Zbigniew; Pawela, Łukasz; Życzkowski, Karol

2018-05-01

In this work, we analyze properties of generic quantum channels in the case of large system size. We use random matrix theory and free probability to show that the distance between two independent random channels converges to a constant value as the dimension of the system grows larger. As a measure of the distance we use the diamond norm. In the case of a flat Hilbert-Schmidt distribution on quantum channels, we obtain that the distance converges to 1/2 +2/π , giving also an estimate for the maximum success probability for distinguishing the channels. We also consider the problem of distinguishing two random unitary rotations.

Quantum control and process tomography of a semiconductor quantum dot hybrid qubit.

PubMed

Kim, Dohun; Shi, Zhan; Simmons, C B; Ward, D R; Prance, J R; Koh, Teck Seng; Gamble, John King; Savage, D E; Lagally, M G; Friesen, Mark; Coppersmith, S N; Eriksson, Mark A

2014-07-03

The similarities between gated quantum dots and the transistors in modern microelectronics--in fabrication methods, physical structure and voltage scales for manipulation--have led to great interest in the development of quantum bits (qubits) in semiconductor quantum dots. Although quantum dot spin qubits have demonstrated long coherence times, their manipulation is often slower than desired for important future applications, such as factoring. Furthermore, scalability and manufacturability are enhanced when qubits are as simple as possible. Previous work has increased the speed of spin qubit rotations by making use of integrated micromagnets, dynamic pumping of nuclear spins or the addition of a third quantum dot. Here we demonstrate a qubit that is a hybrid of spin and charge. It is simple, requiring neither nuclear-state preparation nor micromagnets. Unlike previous double-dot qubits, the hybrid qubit enables fast rotations about two axes of the Bloch sphere. We demonstrate full control on the Bloch sphere with π-rotation times of less than 100 picoseconds in two orthogonal directions, which is more than an order of magnitude faster than any other double-dot qubit. The speed arises from the qubit's charge-like characteristics, and its spin-like features result in resistance to decoherence over a wide range of gate voltages. We achieve full process tomography in our electrically controlled semiconductor quantum dot qubit, extracting high fidelities of 85 per cent for X rotations (transitions between qubit states) and 94 per cent for Z rotations (phase accumulation between qubit states).

Toward efficient fiber-based quantum interface (Conference Presentation)

NASA Astrophysics Data System (ADS)

Soshenko, Vladimir; Vorobyov, Vadim V.; Bolshedvorsky, Stepan; Lebedev, Nikolay; Akimov, Alexey V.; Sorokin, Vadim; Smolyaninov, Andrey

2016-04-01

NV center in diamond is attracting a lot of attention in quantum information processing community [1]. Been spin system in clean and well-controlled environment of diamond it shows outstanding performance as quantum memory even at room temperature, spin control with single shot optical readout and possibility to build up quantum registers even on single NV center. Moreover, NV centers could be used as high-resolution sensitive elements of detectors of magnetic or electric field, temperature, tension, force or rotation. For all of these applications collection of the light emitted by NV center is crucial point. There were number of approaches suggested to address this issue, proposing use of surface plasmoms [2], manufacturing structures in diamond [3] etc. One of the key feature of any practically important interface is compatibility with the fiber technology. Several groups attacking this problem using various approaches. One of them is placing of nanodiamonds in the holes of photonic crystal fiber [4], another is utilization of AFM to pick and place nanodiamond on the tapered fiber[5]. We have developed a novel technique of placing a nanodiamond with single NV center on the tapered fiber by controlled transfer of a nanodiamond from one "donor" tapered fiber to the "target" clean tapered fiber. We verify our ability to transfer only single color centers by means of measurement of second order correlation function. With this technique, we were able to double collection efficiency of confocal microscope. The majority of the factors limiting the collection of photons via optical fiber are technical and may be removed allowing order of magnitude improved in collection. We also discuss number of extensions of this technique to all fiber excitation and integration with nanostructures. References: [1] Marcus W. Doherty, Neil B. Manson, Paul Delaney, Fedor Jelezko, Jörg Wrachtrup, Lloyd C.L. Hollenberg , " The nitrogen-vacancy colour centre in diamond," Physics Reports, vol. 528, no. 1, p. 1-45, 2013. [2] A.V. Akimov, A. Mukherjee, C.L. Yu, D.E. Chang, A.S. Zibrov, P.R. Hemmer, H. Park and M.D. Lukin, "Generation of single optical plasmons in metallic nanowires coupled to quantum dots," Nature, vol. 450, p. 402-406, 2007. [3] Michael J. Burek , Yiwen Chu, Madelaine S.Z. Liddy, Parth Patel, Jake Rochman , Srujan Meesala, Wooyoung Hong, Qimin Quan, Mikhail D. Lukin and Marko Loncar High quality-factor optical nanocavities in bulk single-crystal diamond, Nature communications 6718 (2014) [4] Tim Schroder, Andreas W. Schell, Gunter Kewes, Thomas Aichele, and Oliver Benson Fiber-Integrated Diamond-Based Single Photon Source, Nano Lett. 2011, 11, 198-202 [5]Lars Liebermeister, et. al. "Tapered fiber coupling of single photons emitted by a deterministically positioned single nitrogen vacancy center", Appl. Phys. Lett. 104, 031101 (2014)

Impact resistance and energies of intermetallic bonded diamond composites and polycrystalline diamond compacts and their comparison

NASA Astrophysics Data System (ADS)

Gorla, Sai Prasanth

Chemistry of intermetallic bonded diamond is studied. The impact resistance and energies of intermetallic bonded diamond is compared to current poly crystalline diamond compacts. IBD's are found to have high standards of hardness and have more impact energies absorbed. Intermetallic bonded diamond composite comprises of diamond particles dispersed in Tungsten carbide using Nickel aluminide (Ni3Al) as binder. In previous research conducted on IBD's, diamonds are successfully dispersed in intermetallic alloy of nickel aluminide and processed at 1350°C such that diamond particles remain intact without forming graphite. Composites are formed by milling, pressing the intermetallic binder and diamond particles and sintering at high temperature conditions.

Diamond tool machining of materials which react with diamond

DOEpatents

Lundin, R.L.; Stewart, D.D.; Evans, C.J.

1992-04-14

An apparatus is described for the diamond machining of materials which detrimentally react with diamond cutting tools in which the cutting tool and the workpiece are chilled to very low temperatures. This chilling halts or retards the chemical reaction between the workpiece and the diamond cutting tool so that wear rates of the diamond tool on previously detrimental materials are comparable with the diamond turning of materials which do not react with diamond. 1 figs.

Self-composite comprised of nanocrystalline diamond and a non-diamond component useful for thermoelectric applications

DOEpatents

Gruen, Dieter M.

2012-09-04

One provides nanocrystalline diamond material that comprises a plurality of substantially ordered diamond crystallites that are sized no larger than about 10 nanometers. One then disposes a non-diamond component within the nanocrystalline diamond material. By one approach this non-diamond component comprises an electrical conductor that is formed at the grain boundaries that separate the diamond crystallites from one another. The resultant nanowire is then able to exhibit a desired increase with respect to its ability to conduct electricity while also preserving the thermal conductivity behavior of the nanocrystalline diamond material.

Self-composite comprised of nanocrystalline diamond and a non-diamond component useful for thermoelectric applications

DOEpatents

Gruen, Dieter M [Downers Grove, IL

2009-08-11

One provides nanocrystalline diamond material that comprises a plurality of substantially ordered diamond crystallites that are sized no larger than about 10 nanometers. One then disposes a non-diamond component within the nanocrystalline diamond material. By one approach this non-diamond component comprises an electrical conductor that is formed at the grain boundaries that separate the diamond crystallites from one another. The resultant nanowire is then able to exhibit a desired increase with respect to its ability to conduct electricity while also preserving the thermal conductivity behavior of the nanocrystalline diamond material.

Universal planetary tectonics (supertectonics)

NASA Astrophysics Data System (ADS)

Kochemasov, G. G.

2009-04-01

Universal planetary tectonics (supertectonics) G. Kochemasov IGEM of the Russian Academy of Sciences, Moscow, Russia, kochem.36@mail.ru The wave planetology [1-3 & others] proceeds from the following: "planetary structures are made by orbits and rotations". A uniform reason makes uniform structures. Inertia-gravity waves arising in planetary bodies due to their movements in Keplerian elliptical orbits with periodically changing accelerations warp these bodies in such way that they acquire polyhedron shapes (after interference of standing waves of four directions). Strong Newtonian gravity makes bodies larger than ~400 to 500 km in diameter globular and polyhedra are rarely seen. Only geomorphologic, geologic and geophysical mapping can develop these hidden structures. But small bodies, normally less than ~ 300 to 400 km in diameter, often show parts of the polyhedra, rarely fully developed forms (the asteroid Steins and satellite Amalthea present rather perfect forms of "diamond"). Depending on warping wavelengths (they make harmonics) various Plato's figures superimposed on each other can be distinguished. The fundamental wave 1 produces a tetrahedron, intrinsically dichotomic figure in which a vertex (contraction) always is opposed to a face (expansion). From the recent examples the best is the saturnian northern hexagon (a face) opposed to the southern hurricane (a vertex). The first overtone wave 2 is responsible for creation of structural octahedra. Whole ‘diamonds" and their parts are known [4, 5]. Other overtones produce less developed (because of smaller wave amplitudes) planetary shapes complicating main forms. Thus, the first common structural peculiarity of planetary bodies is their polyhedron nature. Not less important is the second common structural peculiarity. As all globular or smaller more or less isometric bodies rotate, they have an angular momentum. It is inevitably different in tropic and extra-tropic belts having uneven radii or distances to the rotation axe. But this unevenness is undesirable because it creates tectonic stresses and increases energetic status that is against the natural tendency to minimize these physical characteristics. So, a body tends to lower angular momentum of tropics and increase it in extra-tropics. With the same angular velocity it remains only mass and radius to play in this tendency. Tropical belt is destructed (for an example, the lithosphere disintegration in solid bodies), extra-tropical belts add dense material (plumes), expand - the constructive tendency [6]. Both tectonic peculiarities-polyhedrons and constructive - destructive tendencies - are common for celestial bodies of various classes. They are characteristic for our star, planets, satellites and small bodies. That is why a term "supertectonics" seems rather suitable. References: [1] Kochemasov G.G. Concerted wave supergranulation of the solar system bodies // 16th Russian-American microsymposium on planetology, Abstracts, Moscow, Vernadsky Inst. (GEOKHI), 1992, 36-37. [2] Kochemasov G.G. Tectonic dichotomy, sectoring and granulation of Earth and other celestial bodies // Proceedings of the International Symposium on New Concepts in Global Tectonics, "NCGT-98 TSUKUBA", Geological Survey of Japan, Tsukuba, Nov 20-23, 1998, p. 144-147. [3] Kochemasov G.G. Theorems of wave planetary tectonics // Geophys. Res. Abstr., 1999, V.1, №3, 700. [4] Kochemasov G.G. Plato' polyhedra as shapes of small icy satellites // Geophys. Res. Abstracts, Vol. 10, 2008, EGU2008-A-01271, CD-ROM; [5] Kochemasov G.G. (1999) "Diamond" and "dumb-bells"-like shapes of celestial bodies induced by inertia-gravity waves // 30th Vernadsky-Brown microsymposium on comparative planetology, Abstracts, Moscow, Vernadsky Inst.,, 49-50; [6] Kochemasov G.G. Tectonics of rotating celestial globes // Vernadsky-Brown microsymposium 48, 20-22 Oct. 2008, Moscow, Abstr. m48_20.

Field testing advanced geothermal turbodrill (AGT). Phase 1 final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maurer, W.C.; Cohen, J.H.

1999-06-01

Maurer Engineering developed special high-temperature geothermal turbodrills for LANL in the 1970s to overcome motor temperature limitations. These turbodrills were used to drill the directional portions of LANL`s Hot Dry Rock Geothermal Wells at Fenton Hill, New Mexico. The Hot Dry Rock concept is to drill parallel inclined wells (35-degree inclination), hydraulically fracture between these wells, and then circulate cold water down one well and through the fractures and produce hot water out of the second well. At the time LANL drilled the Fenton Hill wells, the LANL turbodrill was the only motor in the world that would drill atmore » the high temperatures encountered in these wells. It was difficult to operate the turbodrills continuously at low speed due to the low torque output of the LANL turbodrills. The turbodrills would stall frequently and could only be restarted by lifting the bit off bottom. This allowed the bit to rotate at very high speeds, and as a result, there was excessive wear in the bearings and on the gauge of insert roller bits due to these high rotary speeds. In 1998, Maurer Engineering developed an Advanced Geothermal Turbodrill (AGT) for the National Advanced Drilling and Excavation Technology (NADET) at MIT by adding a planetary speed reducer to the LANL turbodrill to increase its torque and reduce its rotary speed. Drilling tests were conducted with the AGT using 12 1/2-inch insert roller bits in Texas Pink Granite. The drilling tests were very successful, with the AGT drilling 94 ft/hr in Texas Pink Granite compared to 45 ft/hr with the LANL turbodrill and 42 ft/hr with a rotary drill. Field tests are currently being planned in Mexico and in geothermal wells in California to demonstrate the ability of the AGT to increase drilling rates and reduce drilling costs.« less

n-Type diamond and method for producing same

DOEpatents

Anderson, Richard J.

2002-01-01

A new n-type semiconducting diamond is disclosed, which is doped with n-type dopant atoms. Such diamond is advantageously formed by chemical vapor deposition from a source gas mixture comprising a carbon source compound for the diamond, and a volatile hot wire filament for the n-type impurity species, so that the n-type impurity atoms are doped in the diamond during its formation. A corresponding chemical vapor deposition method of forming the n-type semiconducting diamond is disclosed. The n-type semiconducting diamond of the invention may be usefully employed in the formation of diamond-based transistor devices comprising pn diamond junctions, and in other microelectronic device applications.

Diamond anvil cells using boron-doped diamond electrodes covered with undoped diamond insulating layer

NASA Astrophysics Data System (ADS)

Matsumoto, Ryo; Yamashita, Aichi; Hara, Hiroshi; Irifune, Tetsuo; Adachi, Shintaro; Takeya, Hiroyuki; Takano, Yoshihiko

2018-05-01

Diamond anvil cells using boron-doped metallic diamond electrodes covered with undoped diamond insulating layers have been developed for electrical transport measurements under high pressure. These designed diamonds were grown on a bottom diamond anvil via a nanofabrication process combining microwave plasma-assisted chemical vapor deposition and electron beam lithography. The resistance measurements of a high-quality FeSe superconducting single crystal under high pressure were successfully demonstrated by just putting the sample and gasket on the bottom diamond anvil directly. The superconducting transition temperature of the FeSe single crystal was increased to up to 43 K by applying uniaxial-like pressure.

High-density fluids and the growth of monocrystalline diamonds

NASA Astrophysics Data System (ADS)

Weiss, Y.; Kiflawi, I.; Davies, N.; Navon, O.

2014-09-01

The chemical nature and composition of the growth medium of monocrystalline (MC) diamonds is still a matter of debate, partially because carbonate-bearing high-density fluids (HDFs) that are common in fibrous diamonds have not been found in MC diamonds. Here we report the first finding of HDF microinclusions in a MC octahedral diamond from Finsch, South Africa and in the MC octahedral core of a coated diamond from Kankan, Guinea; both diamonds carry nitrogen in B-centers. Numerous microinclusions in diamond Finsch_2a_cap1 are restricted to two thin layers parallel to the (1 1 1) face, ∼20 and 200 μm from the diamond rim. Low-Mg carbonatitic HDFs are found along the inner layer while the outer layer trapped saline compositions. The major and trace element compositions of the inclusions and their infrared spectra are highly similar to those of microinclusions found in fibrous diamonds. A few isolated microinclusions of saline compositions are scattered around a sulfide inclusion in the center of the octahedral core of diamond ON-KAN-383. This evidence for the involvement of oxidized fluids in the formation of MC diamonds adds to previous reports on the antiquity of HDFs in fibrous diamonds, the presence of carbonate and halide phases in inclusions in MC diamonds and the similarity of trace element pattern of a MC diamond to those of low-Mg carbonatitic HDF in fibrous diamonds. In addition, we show that the interaction of HDFs with depleted garnets can produce sinusoidal REE patterns which are one of the primary features of lherzolitic and harzburgitic garnet inclusions in MC diamonds. Together, these observations suggest that HDFs are involved in the formation of many types of diamonds from the Archaean to the Phanerozoic. HDFs are trapped in large quantities during rapid, fibrous growth, but must also be present during the growth of many MC diamonds.

A new phase transformation path from nanodiamond to new-diamond via an intermediate carbon onion

NASA Astrophysics Data System (ADS)

Xiao, J.; Li, J. L.; Liu, P.; Yang, G. W.

2014-11-01

The investigation of carbon allotropes such as graphite, diamond, fullerenes, nanotubes and carbon onions and mechanisms that underlie their mutual phase transformation is a long-standing problem of great fundamental importance. New diamond (n-diamond) is a novel metastable phase of carbon with a face-centered cubic structure; it is called ``new diamond'' because many reflections in its electron diffraction pattern are similar to those of diamond. However, producing n-diamond from raw carbon materials has so far been challenging due to n-diamond's higher formation energy than that of diamond. Here, we, for the first time, demonstrate a new phase transformation path from nanodiamond to n-diamond via an intermediate carbon onion in the unique process of laser ablation in water, and establish that water plays a crucial role in the formation of n-diamond. When a laser irradiates colloidal suspensions of nanodiamonds at ambient pressure and room temperature, nanodiamonds are first transformed into carbon onions serving as an intermediate phase, and sequentially carbon onions are transformed into n-diamonds driven by the laser-induced high temperature and high pressure from the carbon onion as a nanoscaled temperature and pressure cell upon the process of laser irradiation in a liquid. This phase transformation not only provides new insight into the physical mechanism involved, but also offers one suitable opportunity for breaking controllable pathways between n-diamond and carbon allotropes such as diamond and carbon onions.The investigation of carbon allotropes such as graphite, diamond, fullerenes, nanotubes and carbon onions and mechanisms that underlie their mutual phase transformation is a long-standing problem of great fundamental importance. New diamond (n-diamond) is a novel metastable phase of carbon with a face-centered cubic structure; it is called ``new diamond'' because many reflections in its electron diffraction pattern are similar to those of diamond. However, producing n-diamond from raw carbon materials has so far been challenging due to n-diamond's higher formation energy than that of diamond. Here, we, for the first time, demonstrate a new phase transformation path from nanodiamond to n-diamond via an intermediate carbon onion in the unique process of laser ablation in water, and establish that water plays a crucial role in the formation of n-diamond. When a laser irradiates colloidal suspensions of nanodiamonds at ambient pressure and room temperature, nanodiamonds are first transformed into carbon onions serving as an intermediate phase, and sequentially carbon onions are transformed into n-diamonds driven by the laser-induced high temperature and high pressure from the carbon onion as a nanoscaled temperature and pressure cell upon the process of laser irradiation in a liquid. This phase transformation not only provides new insight into the physical mechanism involved, but also offers one suitable opportunity for breaking controllable pathways between n-diamond and carbon allotropes such as diamond and carbon onions. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr05246c

31 CFR 592.310 - Rough diamond.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn, cleaved...

31 CFR 592.310 - Rough diamond.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn, cleaved...

31 CFR 592.310 - Rough diamond.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Rough diamond. 592.310 Section 592... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn...

31 CFR 592.310 - Rough diamond.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn, cleaved...

31 CFR 592.310 - Rough diamond.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Rough diamond. 592.310 Section 592.310... ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS General Definitions § 592.310 Rough diamond. The term rough diamond means any diamond that is unworked or simply sawn, cleaved...

Diamond bio electronics.

PubMed

Linares, Robert; Doering, Patrick; Linares, Bryant

2009-01-01

The use of diamond for advanced applications has been the dream of mankind for centuries. Until recently this dream has been realized only in the use of diamond for gemstones and abrasive applications where tons of diamonds are used on an annual basis. Diamond is the material system of choice for many applications, but its use has historically been limited due to the small size, high cost, and inconsistent (and typically poor) quality of available diamond materials until recently. The recent development of high quality, single crystal diamond crystal growth via the Chemical Vapor Deposition (CVD) process has allowed physcists and increasingly scientists in the life science area to think beyond these limitations and envision how diamond may be used in advanced applications ranging from quantum computing, to power generation and molecular imaging, and eventually even diamond nano-bots. Because of diamond's unique properties as a bio-compatible material, better understanding of diamond's quantum effects and a convergence of mass production, semiconductor-like fabrication process, diamond now promises a unique and powerful key to the realization of the bio-electronic devices being envisioned for the new era of medical science. The combination of robust in-the-body diamond based sensors, coupled with smart bio-functionalized diamond devices may lead to diamond being the platform of choice for bio-electronics. This generation of diamond based bio-electronic devices would contribute substantially to ushering in a paradigm shift for medical science, leading to vastly improved patient diagnosis, decrease of drug development costs and risks, and improved effectiveness of drug delivery and gene therapy programs through better timed and more customized solutions.

Optimizing friction stir weld parameters of aluminum and copper using conventional milling machine

NASA Astrophysics Data System (ADS)

Manisegaran, Lohappriya V.; Ahmad, Nurainaa Ayuni; Nazri, Nurnadhirah; Noor, Amirul Syafiq Mohd; Ramachandran, Vignesh; Ismail, Muhammad Tarmizizulfika; Ahmad, Ku Zarina Ku; Daruis, Dian Darina Indah

2018-05-01

The joining of two of any particular materials through friction stir welding (FSW) are done by a rotating tool and the work piece material that generates heat which causes the region near the FSW tool to soften. This in return will mechanically intermix the work pieces. The first objective of this study is to join aluminum plates and copper plates by means of friction stir welding process using self-fabricated tools and conventional milling machine. This study also aims to investigate the optimum process parameters to produce the optimum mechanical properties of the welding joints for Aluminum plates and Copper plates. A suitable tool bit and a fixture is to be fabricated for the welding process. A conventional milling machine will be used to weld the aluminum and copper. The most important parameters to enable the process are speed and pressure of the tool (or tool design and alignment of the tool onto the work piece). The study showed that the best surface finish was produced from speed of 1150 rpm and tool bit tilted to 3°. For a 200mm × 100mm Aluminum 6061 with plate thickness of 2 mm at a speed of 1 mm/s, the time taken to complete the welding is only 200 seconds or equivalent to 3 minutes and 20 seconds. The Copper plates was successfully welded using FSW with tool rotation speed of 500 rpm, 700 rpm, 900 rpm, 1150 rpm and 1440 rpm and with welding traverse rate of 30 mm/min, 60 mm/min and 90 mm/min. As the conclusion, FSW using milling machine can be done on both Aluminum and Copper plates, however the weld parameters are different for the two types of plates.

Security proof of a three-state quantum-key-distribution protocol without rotational symmetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fung, C.-H.F.; Lo, H.-K.

2006-10-15

Standard security proofs of quantum-key-distribution (QKD) protocols often rely on symmetry arguments. In this paper, we prove the security of a three-state protocol that does not possess rotational symmetry. The three-state QKD protocol we consider involves three qubit states, where the first two states |0{sub z}> and |1{sub z}> can contribute to key generation, and the third state |+>=(|0{sub z}>+|1{sub z}>)/{radical}(2) is for channel estimation. This protocol has been proposed and implemented experimentally in some frequency-based QKD systems where the three states can be prepared easily. Thus, by founding on the security of this three-state protocol, we prove that thesemore » QKD schemes are, in fact, unconditionally secure against any attacks allowed by quantum mechanics. The main task in our proof is to upper bound the phase error rate of the qubits given the bit error rates observed. Unconditional security can then be proved not only for the ideal case of a single-photon source and perfect detectors, but also for the realistic case of a phase-randomized weak coherent light source and imperfect threshold detectors. Our result in the phase error rate upper bound is independent of the loss in the channel. Also, we compare the three-state protocol with the Bennett-Brassard 1984 (BB84) protocol. For the single-photon source case, our result proves that the BB84 protocol strictly tolerates a higher quantum bit error rate than the three-state protocol, while for the coherent-source case, the BB84 protocol achieves a higher key generation rate and secure distance than the three-state protocol when a decoy-state method is used.« less

Development of a ReaxFF Potential for Carbon Condensed Phases and Its Application to the Thermal Fragmentation of a Large Fullerene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Srinivasan, Sriram Goverapet; van Duin, Adri C. T.; Ganesh, P.

2015-01-20

In this article, we report the development of a ReaxFF reactive potential that can accurately describe the chemistry and dynamics of carbon condensed phases. Density functional theory (DFT)-based calculations were performed to obtain the equation of state for graphite and diamond and the formation energies of defects in graphene and amorphous phases from fullerenes. The DFT data were used to reparametrize ReaxFFCHO, resulting in a new potential called ReaxFFC-2013. ReaxFFC-2013 accurately predicts the atomization energy of graphite and closely reproduces the DFT-based energy difference between graphite and diamond, and the barrier for transition from graphite to diamond. ReaxFFC-2013 also accuratelymore » predicts the DFT-based energy barrier for Stone–Wales transformation in a C60(Ih) fullerene through the concerted rotation of a C2 unit. Later, MD simulations of a C180 fullerene using ReaxFFC-2013 suggested that the thermal fragmentation of these giant fullerenes is an exponential function of time. An Arrhenius-type equation was fit to the decay rate, giving an activation energy of 7.66 eV for the loss of carbon atoms from the fullerene. Although the decay of the molecule occurs primarily via the loss of C2 units, we observed that, with an increase in temperature, the probability of loss of larger fragments increases. The ReaxFFC-2013 potential developed in this work, and the results obtained on fullerene fragmentation, provide an important step toward the full computational chemical modeling of coal pyrolysis, soot incandescence, high temperature erosion of graphitic rocket nozzles, and ablation of carbon-based spacecraft materials during atmospheric reentry.« less

Development of a ReaxFF potential for carbon condensed phases and its application to the thermal fragmentation of a large fullerene

DOE PAGES

Srinivasan, Sriram Goverapet; Adri C. T. van Duin; Ganesh, Panchapakesan

2015-01-06

In this paper, we report the development of a ReaxFF reactive potential that can accurately describe the chemistry and dynamics of carbon condensed phases. Density functional theory (DFT)-based calculations were performed to obtain the equation of state for graphite and diamond and the formation energies of defects in graphene and amorphous phases from fullerenes. The DFT data were used to reparametrize ReaxFF CHO, resulting in a new potential called ReaxFF C-2013. ReaxFF C-2013 accurately predicts the atomization energy of graphite and closely reproduces the DFT-based energy difference between graphite and diamond, and the barrier for transition from graphite to diamond.more » ReaxFF C-2013 also accurately predicts the DFT-based energy barrier for Stone–Wales transformation in a C 60(I h) fullerene through the concerted rotation of a C 2 unit. Later, MD simulations of a C 180 fullerene using ReaxFF C-2013 suggested that the thermal fragmentation of these giant fullerenes is an exponential function of time. An Arrhenius-type equation was fit to the decay rate, giving an activation energy of 7.66 eV for the loss of carbon atoms from the fullerene. Although the decay of the molecule occurs primarily via the loss of C 2 units, we observed that, with an increase in temperature, the probability of loss of larger fragments increases. Finally, the ReaxFF C-2013 potential developed in this work, and the results obtained on fullerene fragmentation, provide an important step toward the full computational chemical modeling of coal pyrolysis, soot incandescence, high temperature erosion of graphitic rocket nozzles, and ablation of carbon-based spacecraft materials during atmospheric reentry.« less

Microstructure and thermal properties of copper–diamond composites with tungsten carbide coating on diamond particles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kang, Qiping; He, Xinbo, E-mail: xb_he@163.com; Ren, Shubin

2015-07-15

An effective method for preparing tungsten carbide coating on diamond surfaces was proposed to improve the interface bonding between diamond and copper. The WC coating was formed on the diamond surfaces with a reaction medium of WO{sub 3} in mixed molten NaCl–KCl salts and the copper–diamond composites were obtained by vacuum pressure infiltration of WC-coated diamond particles with pure copper. The microstructure of interface bonding between diamond and copper was discussed. Thermal conductivity and thermal expansion behavior of the obtained copper–diamond composites were investigated. Results indicated that the thermal conductivity of as-fabricated composite reached 658 W m{sup −} {sup 1}more » K{sup −} {sup 1}. Significant reduction in coefficient of thermal expansion of the composite compared with that of pure copper was obtained. - Highlights: • WC coating was successfully synthesized on diamond particles in molten salts. • WC coating obviously promoted the wettability of diamond and copper matrix. • WC coating greatly enhanced the thermal conductivity of Cu–diamond composite. • The composites are suitable candidates for heat sink applications.« less

Experimental Evaluation of Beam to Diamond Box Column Connection with Through Plate in Moment Frames

NASA Astrophysics Data System (ADS)

Keshavarzi, Farhad; Mirghaderi, Rasoul; Torabian, Shahabeddin; Imanpour, Ali

2008-07-01

Moment resisting frames with built up section have very enhanced features due to high bending stiffness and strength characteristics in two principal axes and access to column faces for beam to column easy connections. But due to proper transfer of beam stresses to column faces there were always some specific controvertibly issues that how to make the load transfer through and in plane manner in order to mobilize the forces in column faces. Using diamond column instead of box column provide possibility to mobilize the load transfer mechanism in column faces. This section as a column has considerable benefit such as high plastic to elastic section modulus ratio which is an effective factor for force controlled components. Typical connection has no chance to be applied with diamond column. This paper elucidates the seismic behavior of through-plates moment connections to diamond box columns for use in steel moment resisting frames. This connection has a lot of economical benefits such as no need to horizontal continuity plates and satisfying the weak beam—strong column criteria in the connection region. They might serve as panel zone plates as well. According to high shear demand in panel zone of beam to column joint one should use the doublers plates in order to decrease the shear strength demand in this sensitive part of structure but these plates have no possibility to mobilize the load transfer mechanism in column web and transfer them to column flanges. In this type of connection, column faces have effective role in order to decrease the demands on through plate and they are impressive factors for improving the performance of the connection. Experimental analysis was conducted to elucidate the seismic behavior of this connection. The results of Experimental analysis established the effectiveness of the through plate in mitigating local stress concentrations and forming the plastic hinge zone in the beam away from the beam to column interface. The moment-rotation graphs form sub-assemblage show a desirable seismic performance of this connection

Iron Oxide Nanoparticles Employed as Seeds for the Induction of Microcrystalline Diamond Synthesis

PubMed Central

2008-01-01

Iron nanoparticles were employed to induce the synthesis of diamond on molybdenum, silicon, and quartz substrates. Diamond films were grown using conventional conditions for diamond synthesis by hot filament chemical vapor deposition, except that dispersed iron oxide nanoparticles replaced the seeding. X-ray diffraction, visible, and ultraviolet Raman Spectroscopy, energy-filtered transmission electron microscopy , electron energy-loss spectroscopy, and X-ray photoelectron spectroscopy (XPS) were employed to study the carbon bonding nature of the films and to analyze the carbon clustering around the seed nanoparticles leading to diamond synthesis. The results indicate that iron oxide nanoparticles lose the O atoms, becoming thus active C traps that induce the formation of a dense region of trigonally and tetrahedrally bonded carbon around them with the ensuing precipitation of diamond-type bonds that develop into microcrystalline diamond films under chemical vapor deposition conditions. This approach to diamond induction can be combined with dip pen nanolithography for the selective deposition of diamond and diamond patterning while avoiding surface damage associated to diamond-seeding methods.

Episodic diamond growth beneath the Kaapvaal Craton at Jwaneng Mine, Botswana

NASA Astrophysics Data System (ADS)

Gress, Michael U.; Howell, Daniel; Chinn, Ingrid L.; Speich, Laura; Kohn, Simon C.; van den Heuvel, Quint; Schulten, Ellen; Pals, Anna S. M.; Davies, Gareth R.

2018-05-01

Important implications for the interior workings of the Earth can be drawn by studying diamonds and their inclusions. To better understand the timing and number of diamond forming events beneath the NW margin of the Kaapvaal Craton, a comprehensive reassessment of Jwaneng's diamond populations has been undertaken. We report new inclusion abundance data from the visual examination of 130,000 diamonds that validate the predominance of an eclogitic diamond suite (up to 88%) with on average 5% inclusion-bearing diamonds (with inclusions >10 μm in size). From this population, polished plates from 79 diamonds of eclogitic and peridotitic paragenesis have been studied with cathodoluminescence (CL) imaging and infrared spectroscopy (FTIR) traverses. The majority (80%) record major changes in N concentration and aggregation states, as well as sharp boundaries in the CL images of individual plates that are interpreted to demarcate discrete diamond growth events. In addition, bulk FTIR data have been acquired for 373 unpolished diamonds. Silicate inclusions sampled from distinct growth zones define 2 compositional groups of omphacites and pyrope-almandines associated with different N contents in their diamond hosts. These findings reinforce previous observations that at Jwaneng at least seven individual diamond forming events can be identified - 3 peridotitic and 4 eclogitic. The results demonstrate that detailed examination of diamond plates by CL imaging and FTIR traverses is necessary to unveil the complex history recorded in diamonds.

Trace-element patterns of fibrous and monocrystalline diamonds: Insights into mantle fluids

NASA Astrophysics Data System (ADS)

Rege, S.; Griffin, W. L.; Pearson, N. J.; Araujo, D.; Zedgenizov, D.; O'Reilly, S. Y.

2010-08-01

During their growth diamonds may trap micron-scale inclusions of the fluids from which they grew, and these "time capsules" provide insights into the metasomatic processes that have modified the subcontinental lithospheric mantle. LAM-ICPMS analysis of trace elements in > 500 fibrous and monocrystalline diamonds worldwide has been used to understand the nature of these fluids. Analyses of fibrous diamonds define two general types of pattern, a "fibrous-high" (FH) one with high contents of LREE, Ba and K, and a "fibrous-low" (FL) pattern characterized by depletion in LREE/MREE, Ba and K, negative anomalies in Sr and Y, and subchondritic Zr/Hf and Nb/Ta. Both types may be found in fibrous diamonds from single deposits, and in three Yakutian pipes some diamonds show abrupt transitions from inclusion-rich cores with FH patterns to clearer rims with FL patterns. Most monocrystalline diamonds show FL-type patterns, but some have patterns that resemble those of FH fibrous diamonds. Peridotitic and eclogitic monocrystalline diamonds may show either patterns with relatively flat REE, or patterns with more strongly depleted LREE. Kimberlites that contain peridotitic diamonds with "high" patterns also contain eclogitic diamonds with "high" patterns. Strong similarities in the patterns of these two groups of diamonds may suggest high fluid/rock ratios. Many diamonds of the "superdeep" paragenesis have trace-element patterns similar to those of other monocrystalline diamonds. This may be evidence that the trace-element compositions of deep-seated fluids are generally similar to those that form diamonds in the subcontinental lithospheric mantle. The element fractionations observed between the FH and FL patterns are consistent with the immiscible separation of a silicic fluid from a carbonatite-silicate fluid, leaving a residual carbonatitic fluid strongly enriched in LREE, Ba and alkalies. This model would suggest that most monocrystalline diamonds crystallized from the more silicic fraction. Comparison with studies of single fluid inclusions in fibrous diamonds suggests that the FH patterns reflect trapped inclusions of high-Mg and low-Mg carbonatitic high-density fluids. In terms of the rock-forming elements, the fluids that precipitated the rims of some fibrous diamonds (FL pattern) and most monocrystalline diamonds are broadly similar to some hydro-silicic high-density fluids found in fibrous diamonds. However, there are still significant differences between the trace-element patterns of most monocrystalline diamonds and known high-density fluids, and further research is required to understand the formation and growth of these diamonds.

Fluid inclusions in Ebelyakh diamonds: Evidence of CO2 liberation in eclogite and the effect of H2O on diamond habit

NASA Astrophysics Data System (ADS)

Smith, Evan M.; Kopylova, Maya G.; Frezzotti, Maria Luce; Afanasiev, Valentin P.

2015-02-01

Fluid inclusions were studied in six octahedrally-grown, eclogitic diamonds from the Ebelyakh River mine, northern Russia, using microthermometry and Raman spectroscopy. The fluids are CO2-N2 mixtures with 40 ± 4 mol% N2, which are trapped along fractures that healed in the diamond stability field. The CO2-rich composition of the fluids provides the first empirical evidence that CO2 can be liberated as a free phase in eclogite in the diamond stability field of the lithospheric mantle, as has been previously predicted from theory. This finding means that the interpretation of carbon isotopes in eclogitic diamonds should not overlook isotopic fractionation due to CO2 liberation from carbonatitic diamond-forming media as it percolates through eclogites. Preferential nucleation of CO2 bubbles in eclogite compared to peridotite may lead to a rock type-specific fracturing mechanism and sampling bias that would help explain the overabundance of eclogite xenoliths in kimberlites. Fluid inclusions in octahedrally-grown, non-fibrous diamonds from both the studied Ebelyakh diamonds and those from other cratons do not show detectable amounts of water. In comparison, fibrous diamond fluid inclusions typically contain 10-25 wt.% water. The absence of "dry" fluids in fibrous diamonds and the presence of these in octahedrally-grown diamonds may indicate different compositions of fluids equilibrated with these two types of diamonds. If there is variability in the water content in diamond-forming fluids, it should affect diamond growth morphology. Water could be responsible for causing fibrous diamond growth, by inhibiting the advancement of growth steps within octahedral faces.

Nature of diamonds in Yakutian eclogites: views from eclogite tomography and mineral inclusions in diamonds

NASA Astrophysics Data System (ADS)

Anand, Mahesh; Taylor, Lawrence A.; Misra, Kula C.; Carlson, William D.; Sobolev, Nikolai V.

2004-09-01

We have performed dissections of two diamondiferous eclogites (UX-1 and U33/1) from the Udachnaya kimberlite, Yakutia in order to understand the nature of diamond formation and the relationship between the diamonds, their mineral inclusions, and host eclogite minerals. Diamonds were carefully recovered from each xenolith, based upon high-resolution X-ray tomography images and three-dimensional models. The nature and physical properties of minerals, in direct contact with diamonds, were investigated at the time of diamond extraction. Polished sections of the eclogites were made, containing the mould areas of the diamonds, to further investigate the chemical compositions of the host minerals and the phases that were in contact with diamonds. Major- and minor-element compositions of silicate and sulfide mineral inclusions in diamonds show variations among each other, and from those in the host eclogites. Oxygen isotope compositions of one garnet and five clinopyroxene inclusions in diamonds from another Udachnaya eclogite (U51) span the entire range recorded for eclogite xenoliths from Udachnaya. In addition, the reported compositions of almost all clinopyroxene inclusions in U51 diamonds exhibit positive Eu anomaly. This feature, together with the oxygen isotopic characteristics, is consistent with the well-established hypothesis of subduction origin for Udachnaya eclogite xenoliths. It is intuitive to expect that all eclogite xenoliths in a particular kimberlite should have common heritage, at least with respect to their included diamonds. However, the variation in the composition of multiple inclusions within diamonds, and among diamonds, from the same eclogite indicates the involvement of complex processes in diamond genesis, at least in the eclogite xenoliths from Yakutia that we have studied.

Diagnostic Techniques Used to Study Chemical-Vapor-Deposited Diamond Films

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

2000-01-01

The advantages and utility of chemical-vapor-deposited (CVD) diamond as an industrial ceramic can only be realized if the price and quality are right. Until recently, this technology was of interest only to the academic and basic research community. However, interest has grown because of advances made by leading CVD diamond suppliers: 1) Reduction of the cost of CVD polycrystalline diamond deposition below $5/carat ($8/sq cm); 2) Installation of production capacity; 3) Epitaxial growth of CVD single-crystal diamond. Thus, CVD diamond applications and business are an industrial reality. At present, CVD diamond is produced in the form of coatings or wafers. CVD diamond film technology offers a broader technological potential than do natural and high-pressure synthetic diamonds because size, geometry, and eventually cost will not be as limiting. Now that they are cost effective, diamond coatings - with their extreme properties - can be used in a variety of applications. Diamond coatings can improve many of the surface properties of engineering substrate materials, including erosion, corrosion, and wear resistance. Examples of actual and potential applications, from microelectromechanical systems to the wear parts of diamond coatings and related superhard coatings are described. For example, diamond coatings can be used as a chemical and mechanical barrier for the space shuttles check valves, particularly on the guide pins and seat assemblies.

Voltammetric and impedance behaviours of surface-treated nano-crystalline diamond film electrodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, F. B.; Jing, B.; Cui, Y.

2015-04-15

The electrochemical performances of hydrogen- and oxygen-terminated nano-crystalline diamond film electrodes were investigated by cyclic voltammetry and AC impedance spectroscopy. In addition, the surface morphologies, phase structures, and chemical states of the two diamond films were analysed by scanning probe microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, respectively. The results indicated that the potential window is narrower for the hydrogen-terminated nano-crystalline diamond film than for the oxygen-terminated one. The diamond film resistance and capacitance of oxygen-terminated diamond film are much larger than those of the hydrogen-terminated diamond film, and the polarization resistances and double-layer capacitance corresponding to oxygen-terminated diamond filmmore » are both one order of magnitude larger than those corresponding to the hydrogen-terminated diamond film. The electrochemical behaviours of the two diamond film electrodes are discussed.« less

Toward deep blue nano hope diamonds: heavily boron-doped diamond nanoparticles.

PubMed

Heyer, Steffen; Janssen, Wiebke; Turner, Stuart; Lu, Ying-Gang; Yeap, Weng Siang; Verbeeck, Jo; Haenen, Ken; Krueger, Anke

2014-06-24

The production of boron-doped diamond nanoparticles enables the application of this material for a broad range of fields, such as electrochemistry, thermal management, and fundamental superconductivity research. Here we present the production of highly boron-doped diamond nanoparticles using boron-doped CVD diamond films as a starting material. In a multistep milling process followed by purification and surface oxidation we obtained diamond nanoparticles of 10-60 nm with a boron content of approximately 2.3 × 10(21) cm(-3). Aberration-corrected HRTEM reveals the presence of defects within individual diamond grains, as well as a very thin nondiamond carbon layer at the particle surface. The boron K-edge electron energy-loss near-edge fine structure demonstrates that the B atoms are tetrahedrally embedded into the diamond lattice. The boron-doped diamond nanoparticles have been used to nucleate growth of a boron-doped diamond film by CVD that does not contain an insulating seeding layer.

Dual-mode optical microscope based on single-pixel imaging

NASA Astrophysics Data System (ADS)

Rodríguez, A. D.; Clemente, P.; Tajahuerce, E.; Lancis, J.

2016-07-01

We demonstrate an inverted microscope that can image specimens in both reflection and transmission modes simultaneously with a single light source. The microscope utilizes a digital micromirror device (DMD) for patterned illumination altogether with two single-pixel photosensors for efficient light detection. The system, a scan-less device with no moving parts, works by sequential projection of a set of binary intensity patterns onto the sample that are codified onto a modified commercial DMD. Data to be displayed are geometrically transformed before written into a memory cell to cancel optical artifacts coming from the diamond-like shaped structure of the micromirror array. The 24-bit color depth of the display is fully exploited to increase the frame rate by a factor of 24, which makes the technique practicable for real samples. Our commercial DMD-based LED-illumination is cost effective and can be easily coupled as an add-on module for already existing inverted microscopes. The reflection and transmission information provided by our dual microscope complement each other and can be useful for imaging non-uniform samples and to prevent self-shadowing effects.

Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources.

PubMed

Rutherford, Michael E; Chapman, David J; White, Thomas G; Drakopoulos, Michael; Rack, Alexander; Eakins, Daniel E

2016-05-01

The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits).

Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources

PubMed Central

Rutherford, Michael E.; Chapman, David J.; White, Thomas G.; Drakopoulos, Michael; Rack, Alexander; Eakins, Daniel E.

2016-01-01

The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits). PMID:27140147

Designing defect-based qubit candidates in wide-gap binary semiconductors for solid-state quantum technologies

NASA Astrophysics Data System (ADS)

Seo, Hosung; Ma, He; Govoni, Marco; Galli, Giulia

2017-12-01

The development of novel quantum bits is key to extending the scope of solid-state quantum-information science and technology. Using first-principles calculations, we propose that large metal ion-vacancy pairs are promising qubit candidates in two binary crystals: 4 H -SiC and w -AlN. In particular, we found that the formation of neutral Hf- and Zr-vacancy pairs is energetically favorable in both solids; these defects have spin-triplet ground states, with electronic structures similar to those of the diamond nitrogen-vacancy center and the SiC divacancy. Interestingly, they exhibit different spin-strain coupling characteristics, and the nature of heavy metal ions may allow for easy defect implantation in desired lattice locations and ensure stability against defect diffusion. To support future experimental identification of the proposed defects, we report predictions of their optical zero-phonon line, zero-field splitting, and hyperfine parameters. The defect design concept identified here may be generalized to other binary semiconductors to facilitate the exploration of new solid-state qubits.

Hole 504B reclaimed for future drilling

NASA Astrophysics Data System (ADS)

Leg 137 Scientific Drilling Party

Hole 504B, perhaps the most important in situ reference section for the structure and composition of the oceanic crust, has been reopened for future drilling and downhole measurements after remedial operations during Leg 137 of the Ocean Drilling Program. By far the deepest penetration into oceanic crust, Hole 504B had been feared lost when a large diamond bit and assorted hardware (“junk”) broke off in the bottom of the hole at the end of ODP Leg 111 in 1986. Since then ODP's drill ship, JOIDES Resolution, has circumnavigated the globe, with no opportunity to redress this situation. But the objective of deep penetration into the oceanic crust and the hole itself are considered so important by marine Earth scientists that remedial measures in Hole 504B were undertaken as soon as the drill ship returned to the eastern Pacific. These measures succeeded better than had been hoped. Hole 504B was reopened after less than a week of cleaning operations, which included grappling for the lost junk with tools to pull it from the hole (called “fishing”) and grinding or milling the junk away.

The ``Music'' of Light: Optical Resonances for Fun and Profit

NASA Astrophysics Data System (ADS)

Beausoleil, Raymond

Moore's Law has set great expectations that the performance/price ratio of commercially available semiconductor devices will continue to improve exponentially at least until the end of this decade. But the physics of the metal wires that connect the transistors on a silicon chip already places stringent limits on the performance of integrated circuits, making their continued dramatic improvement highly unlikely. In this talk, I will introduce the basic concept of an optical resonance in a microscopic dielectric cavity in the context of the same type of spatial boundary conditions that give each musical instrument its unique sound. Then I will illustrate applications of these resonances to information technology in a variety of forms and functions using examples from my own laboratory at HP, such as chip-scale optical networks, quantum bits based on spins in diamond, and ultrafast optical switches that could become the foundation for a new generation of optical computers. Our goal is to conduct advanced research that could precipitate an ``optical Moore's Law'' and allow exponential performance gains to continue through the end of the next decade.

Infrared Thermal Imaging During Ultrasonic Aspiration of Bone

NASA Astrophysics Data System (ADS)

Cotter, D. J.; Woodworth, G.; Gupta, S. V.; Manandhar, P.; Schwartz, T. H.

Ultrasonic surgical aspirator tips target removal of bone in approaches to tumors or aneurysms. Low profile angled tips provide increased visualization and safety in many high risk surgical situations that commonly were approached using a high speed rotary drill. Utilization of the ultrasonic aspirator for bone removal raised questions about relative amount of local and transmitted heat energy. In the sphenoid wing of a cadaver section, ultrasonic bone aspiration yielded lower thermal rise in precision bone removal than rotary mechanical drills, with maximum temperature of 31 °C versus 69 °C for fluted and 79 °C for diamond drill bits. Mean ultrasonic fragmentation power was about 8 Watts. Statistical studies using tenacious porcine cranium yielded mean power levels of about 4.5 Watts to 11 Watts and mean temperature of less than 41.1 °C. Excessively loading the tip yielded momentary higher power; however, mean thermal rise was less than 8 °C with bone removal starting at near body temperature of about 37 °C. Precision bone removal and thermal management were possible with conditions tested for ultrasonic bone aspiration.

Chemical-Vapor-Deposited Diamond Film

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1999-01-01

This chapter describes the nature of clean and contaminated diamond surfaces, Chemical-vapor-deposited (CVD) diamond film deposition technology, analytical techniques and the results of research on CVD diamond films, and the general properties of CVD diamond films. Further, it describes the friction and wear properties of CVD diamond films in the atmosphere, in a controlled nitrogen environment, and in an ultra-high-vacuum environment.

Electron energy loss spectrometry of interstellar diamonds

NASA Technical Reports Server (NTRS)

Bernatowicz, Thomas J.; Gibbons, Patrick C.; Lewis, Roy S.

1990-01-01

The results are reported of electron energy loss spectra (EELS) measurements on diamond residues from carbonaceous meteorites designed to elucidate the structure and composition of interstellar diamonds. Dynamic effective medium theory is used to model the dielectric properties of the diamonds and in particular to synthesize the observed spectra as mixtures of diamond and various pi-bonded carbons. The results are shown to be quantitatively consistent with the idea that diamonds and their surfaces are the only contributors to the electron energy loss spectra of the diamond residues and that these peculiar spectra are the result of the exceptionally small grain size and large specific surface area of the interstellar diamonds.

Diamond/diamond-like carbon coated nanotube structures for efficient electron field emission

NASA Technical Reports Server (NTRS)

Dimitrijevic, Steven (Inventor); Withers, James C. (Inventor); Loutfy, Raouf O. (Inventor)

2005-01-01

The present invention is directed to a nanotube coated with diamond or diamond-like carbon, a field emitter cathode comprising same, and a field emitter comprising the cathode. It is also directed to a method of preventing the evaporation of carbon from a field emitter comprising a cathode comprised of nanotubes by coating the nanotube with diamond or diamond-like carbon. In another aspect, the present invention is directed to a method of preventing the evaporation of carbon from an electron field emitter comprising a cathode comprised of nanotubes, which method comprises coating the nanotubes with diamond or diamond-like carbon.

Fabrication of microchannels in polycrystalline diamond using pre-fabricated Si substrates

NASA Astrophysics Data System (ADS)

Chandran, Maneesh; Elfimchev, Sergey; Michaelson, Shaul; Akhvlediani, Rozalia; Ternyak, Orna; Hoffman, Alon

2017-10-01

In this paper, we report on a simple, feasible method to fabricate microchannels in diamond. Polycrystalline diamond microchannels were produced by fabricating trenches in a Si wafer and subsequently depositing a thin layer of diamond onto this substrate using the hot filament vapor deposition technique. Fabrication of trenches in the Si substrate at different depths was carried out by standard photolithography, and the subsequent deposition of the diamond layer was performed by the hot filament chemical vapor deposition technique. The growth mechanism of diamond that leads to the formation of closed diamond microchannels is discussed in detail based on the Knudsen number and growth chemistry of diamond. Variations in the crystallite size, crystalline quality, and thickness of the diamond layer along the trench depths were systematically analyzed using cross-sectional scanning electron microscopy and Raman spectroscopy. Defect density and formation of non-diamond forms of carbon in the diamond layer were found to increase with the trench depth, which sets a limit of 5-45 μm trench depth (or an aspect ratio of 1-9) for the fabrication of diamond microchannels using this method under the present conditions.

Diamond For Optical Material

NASA Astrophysics Data System (ADS)

Clay, Robert D.; Clay, John P.

1984-12-01

Clay Engineering Inc. currently has a proposal before DARPA to manufacture large optical quality diamond for use as optical material. The manufactured diamond will be approximately 100 mm in diameter by 100 mm long. The cost of producing the diamond is expected to be three dollars per carat. It is expected that total impurities of a few parts per billion can readily be obtained. A study of diamond is a study of the effects of impurities. The elements boron and nitrogen can replace carbon atoms in the lattice structure, making diamond a "P" or "N" type semiconductor. Diamonds which are not semiconductors are classified as type IIa. The presence of B or N in the lattice causes diamond to photoconduct in ultraviolet light. All type I and III) and most type IIa diamonds photoconduct. The manufactured diamond will not photoconduct and will have an electrical resistivity greater than 1018 ohm*m. All non-lattice impurities are in the form of inclusions which dramatically affect the mechanical properties of diamond. High purity diamond has a coefficient of absorption of order 10-3 cm-1 at wavelengths of 8 to 12 micro metres, which makes it useful for infrared applications. It also has a low coefficient of absorption at wavelengths greater than 12 micro metres. For missile and aircraft applications, diamond is relatively immune to erosion or pitting damage by sand and rain. Diamond will readily withstand the stagnation temperature of Mach 3 flight and will go to Mach 4.8 with an anti-reflective coating to protect it from oxygen attack. Diamond is highly resistant to thermal shock, which makes it valuable for high energy laser applications. Using R = St (1-)) k/Ea as a measure of thermal shock resistance, diamond is 107 w/m vs "sapphire" and Zerodur at 104 and fused quartz at 1.45x103. Diamond does not perform well in the 2.5-7.5 micro metres and less than 0.4 micro metres wavelengths. Intense beams of less than 0.4 micro metres energy can create color centers in diamond. For laser pulses of such short duration that thermal shock is not a problem, diamond will take less peak power than some competing materials, such as quartz. One could take advantage of the superior strength of diamond and use a thinner slice to obtain equal peak power capacity.

Bases of the Mantle-Carbonatite Conception of Diamond Genesis

NASA Astrophysics Data System (ADS)

Litvin, Yuriy; Spivak, Anna; Kuzyura, Anastasia

2016-04-01

In the mantle-carbonatite conception of diamond genesis, the results of physic-chemical experiments are coordinated with the data of analytic mineralogy of primary inclusions in natural diamonds. Generalization of the solutions of principal genetic problems constitutes the bases of the conception. The solutions are following: (1) it is grounded that diamond-parental melts of the upper mantle have peridotite/eclogite - carbonatite - carbon compositions, of the transition zone - (wadsleite↔ringwoodite) - majorite - stishovite - carbonatite - carbon compositions, and of the lower mantle - periclase/wustite - bridgmanite - Ca-perovskite -stishovite - carbonatite - carbon compositions; (2) a construction of generalized diagrams for the diamond-parental media, which reveal changeable compositions of the growth melts of diamonds and associated phases, their genetic relations to the mantle substance, and classification connections of the primary inclusions in natural diamonds; (3) experimental equilibrium phase diagrams of syngenesis of diamonds and primary inclusions, which characterize the nucleation and growth conditions of diamonds and a capture of paragenetic and xenogenetic minerals by the growing diamonds; (4) a determination of the phase diagrams of diamonds and inclusions syngenesis under the regime of fractional crystallization, which discover the regularities of ultrabasic-basic evolution and paragenesis transitions in the diamond-forming systems of the upper and lower mantle. The evidence of the physic-chemically united mode of diamond genesis at the mantle depths with different mineralogy is obtained. References. Litvin Yu.A. (2007). High-pressure mineralogy of diamond genesis. In: Advances in High-Pressure Mineralogy (edited by Eiji Ohtani), Geological Society of America Special paper 421, 83-103. Litvin Yu.A. (2012). Experimental study of physic-chemical conditions of natural diamond formation on an example of the eclogite-carbonatite-sulphide-diamond system. Geology of Ore Deposits. 54(6), 523-539. Litvin Yu.A., Spivak A.V., Solopova N.A., Dubrovinsky L.S. (2014). On origin of lower-mantle diamonds and their primary inclusions. Physics of the Earth and Planetary Interiors, 228 (The Liebermann Volume), 176-185. http://dx.doi.org/10.1016/j/pepi/2013.12.007

Alluvial Diamond Resource Potential and Production Capacity Assessment of Ghana

USGS Publications Warehouse

Chirico, Peter G.; Malpeli, Katherine C.; Anum, Solomon; Phillips, Emily C.

2010-01-01

In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflictual concerns. This meeting was supported later in 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberley Process Certification Scheme (KPCS) was ratified and signed by both diamond-producing and diamond-importing countries. Over 70 countries were included as members at the end of 2007. To prevent trade in 'conflict' diamonds while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging. The objective of this study was to assess the alluvial diamond resource endowment and current production capacity of the alluvial diamond-mining sector in Ghana. A modified volume and grade methodology was used to estimate the remaining diamond reserves within the Birim and Bonsa diamond fields. The production capacity of the sector was estimated using a formulaic expression of the number of workers reported in the sector, their productivity, and the average grade of deposits mined. This study estimates that there are approximately 91,600,000 carats of alluvial diamonds remaining in both the Birim and Bonsa diamond fields: 89,000,000 carats in the Birim and 2,600,000 carats in the Bonsa. Production capacity is calculated to be 765,000 carats per year, based on the formula used and available data on the number of workers and worker productivity. Annual production is highly dependent on the international diamond market and prices, the numbers of seasonal workers actively mining in the sector, and environmental conditions, which influence seasonal farming.

Absolute age Determinations on Diamond by Radioisotopic Methods: NOT the way to Accurately Identify Diamond Provenance

NASA Astrophysics Data System (ADS)

Shirey, S. B.

2002-05-01

Gem-quality diamond contains such low abundances of parent-daughter radionuclides that dating the diamond lattice directly by isotopic measurements has been and will be impossible. Absolute ages on diamonds typically are obtained through measurements of their syngenetic mineral inclusions: Rb-Sr in garnet; Sm-Nd in garnet and pyroxene; Re-Os and U-Th-Pb in sulfide; K-Ar in pyroxene; and U-Pb in zircon. The application of the first two isotope schemes in the list requires putting together many inclusions from many diamonds whereas the latter isotope schemes permit ages on single diamonds. The key limitations on the application of these decay pairs are the availability and size of the inclusions, the abundance levels of the radionuclides, and instrumental sensitivity. Practical complications of radioisotope dating of inclusions are fatal to the application of the technique for diamond provenance. In all mines, the ratio of gem-quality diamonds to stones with datable inclusions is very high. Thus there is no way to date the valuable, marketable stones that are part of the conflict diamond problem, just their rare, flawed cousins. Each analysis destroys the diamond host plus the inclusion and can only be carried out in research labs by highly trained scientists. Thus, these methods can not be automated or applied to the bulk of diamond production. The geological problems with age dating are equally fatal to its application to diamond provenance. From the geological perspective, for age determination to work as a tool for diamond provenance studies, diamond ages would have to be specific to particular kimberlites or kimberlite fields and different between fields. The southern African Kaapvaal-Zimbabwe Craton and Limpopo Mobile Belt is the only cratonic region where age determinations have been applied on a large enough scale to a number of kimberlites to illustrate the geological problems in age measurements for diamond provenance. However, this southern African example is seen as typical of other cratons. Here, the nearly universal occurrence of Archean or Proterozoic diamonds in much younger (often Cretaceous) kimberlites proves that diamonds are xenocrysts inherited from the ancient mantle lithospheric keel by the host kimberlite as it erupts. Differences in diamond ages are on the scale of the geological assembly of the mantle lithospheric keel and relate to geological terranes in the lithosphere; they have little to do with individual kimberlites. In southern Africa, two age groupings of diamonds exist: Archean (3.2 to 2.9 Ga) diamonds associated with initial creation/final stabilization of the mantle lithosphere and Proterozoic (1 to 2 Ga) diamonds associated with compositional changes to the mantle keel from magmatism and metasomatism. The distribution of these two age types is cratonwide, encompasses many kimberlites and both age groupings can occur in an individual kimberlite. One expects a recurrence of similar ages with a possible 2 Ga age spread from many different kimberlites across the craton. Similar old ages are seen on other cratons (e.g. Siberian, Slave); thus age can not even distinguish diamond source at the scale of a craton. A further complication is that both sampling of diamonds from their lithospheric host and the resting position of diamonds at the final solidification level of the kimberlite in the crust are accidental. This can produce significant variability in the diamond population which is further complicated if erosion and deposition of the diamonds to form alluvial deposits has obscured their host kimberlite.

Diamonds in an Archean greenstone belt: Diamond suites in unconventional rocks of Wawa, Northern Ontario (Canada)

NASA Astrophysics Data System (ADS)

Kopylova, Maya; Bruce, Loryn; Ryder, John

2010-05-01

Diamonds typically are found on Archean cratons entrained by younger Phanerozoic kimberlites. In contrast, Wawa diamonds are hosted in "unconventional", non-kimberlitic rocks that formed contemporaneously with the mafic and sedimentary rocks of the Archean Michipicoten Greenstone Belt (MGB). We studied two diamond suites that occur within the 2.9-2.7 Ga greenschist facies rocks of MGB located in the southwest portion of the Superior Craton (E. Canada). The first diamond suite henceforth referred to as the Wawa breccia diamonds (384 stones), are hosted in the 2618-2744 Ma calc-alkaline lamprophyres and volcaniclastic breccias, contemporaneous with pillow basalts and felsic volcanics of MGB. The second suite, the Wawa conglomerate diamonds (80 crystals), are hosted in the 2697-2700 Ma poorly sorted sedimentary polymictic conglomerate which is interpreted as a proximal alluvial fan debris flow in a fan-delta environment. The majority of the diamonds was found within the matrix of the conglomerate. The diamondiferous breccia occurs 20 km north of the town of Wawa, whereas the conglomerate is found 12 km northeast of Wawa. Diamonds from the 2 occurrences were characterized and described for provenance studies. Both the breccia and conglomerate diamonds show similar crystal habits, with the predominance of octahedral single crystals and ~ 10% of cubes. The conglomerate diamonds are significantly less resorbed (no resorbtion in 43% of the stones) than the breccia diamonds (8% non-resorbed stones). In both suites, only 21-24% show high degrees of resorption. The majority of crystals in both suites are colourless, with some yellow, brown and grey stones. Conglomerate diamonds had a wider variety of colours that were not seen in the breccia diamonds, including green and pink. The breccia diamonds contain 0-740 ppm N and show two modes of N aggregation at 0-30 and 60-95%. Among the breccia diamonds, Type IaA stones comprise 17%, whereas IaAB stones make up 49% of the population. Diamonds from the conglomerate have nitrogen contents below 400 ppm N, with 47% of the suite being Type IaA stones. Approximately one third of the conglomerate and breccia diamonds belongs to Type II having no measurable N. The two suites of Wawa diamonds, according to the morphology and nitrogen studies, are deemed to be different. The conglomerate diamonds are significantly less resorbed and contain less aggregated N. The diamonds that occur in the Wawa breccia and conglomerate have different primary volcanic sources. We suggest that the primary volcanic rock of the conglomerate diamonds may be a kimberlite, as kimberlitic indicator minerals are found in the matrix of the conglomerate. These indicator minerals garnet, Cr diopside and ilmenite are absent from the diamoniferous lamprophyric breccias. The hypothetical kimberlites may have occured in proximity to the conglomerates as suggested by low mechanical abrasion of the conglomerate diamonds and indicator minerals, and the preservation of garnet kelyphitic rims and Cr-diopside. Our study infers an episode of the Archean, pre-2.7 Ga kimberlite magmatism in MGB, which also experienced multiple emplacement episodes of the 2.7 Ga syn-orogenic diamondiferous calc-alkaline lamprophyres. Despite the distinct origins of the breccia and conglomerate diamonds, they all have similar red-orange-green cathodoluminescence colours controlled by the CL emission mainly at 520 nm. This contrasts with the prevalent CL emission at 415-440 nm commonly observed in kimberlitic and detrital diamonds. We ascribe the red-orange-green CL colours of the two diamond suites of Wawa to the late imprint of metamorphism.

Effective thermal and mechanical properties of polycrystalline diamond films

NASA Astrophysics Data System (ADS)

Cheng, Hao-Yu; Yang, Chi-Yuan; Yang, Li-Chueh; Peng, Kun-Cheng; Chia, Chih-Ta; Liu, Shiu-Jen; Lin, I.-Nan; Lin, Kung-Hsuan

2018-04-01

Polycrystalline diamond films were demonstrated as good candidates for electron field emitters, and their mechanical/thermal properties should thus be considered for real devices. We utilized ultrafast optical techniques to investigate the phonon dynamics of several polycrystalline diamond films, prepared by microwave plasma enhanced chemical vapor deposition. The mechanical properties (longitudinal acoustic velocity) and thermal conductivities of diamond films were evaluated from the coherent and incoherent phonon dynamics, respectively. Ultrananocrystalline diamond films were grown using a CH4 (2%)/Ar plasma, while microcrystalline diamond films were grown using a CH4 (2%)/H2 plasma. The ultrananocrystalline diamond film (with a grain size of several nanometers) possesses low acoustic velocity (14.5 nm/ps) and low thermal conductivity (3.17 W/m K) compared with other kinds of diamond films. The acoustic velocity of diamond films increased abruptly to nearly the same as that of natural diamond and remained there when the rod-shaped diamond grains were induced due to the incorporation of H2 in the growth plasma (CH4/Ar). The thermal conductivities of the materials increased monotonously with increasing incorporation of H2 in the growth plasma (CH4/Ar). The thermal conductivity of 25.6 W/m K was attained for nanocrystalline diamond films containing spherical diamond grains (with a size of several tens of nanometers). Compared with single crystalline diamond, the low thermal conductivity of polycrystalline films results from phonon scattering at the interfaces of grains and amorphous carbon in the boundary phases.

Trellis coding with multidimensional QAM signal sets

NASA Technical Reports Server (NTRS)

Pietrobon, Steven S.; Costello, Daniel J.

1993-01-01

Trellis coding using multidimensional QAM signal sets is investigated. Finite-size 2D signal sets are presented that have minimum average energy, are 90-deg rotationally symmetric, and have from 16 to 1024 points. The best trellis codes using the finite 16-QAM signal set with two, four, six, and eight dimensions are found by computer search (the multidimensional signal set is constructed from the 2D signal set). The best moderate complexity trellis codes for infinite lattices with two, four, six, and eight dimensions are also found. The minimum free squared Euclidean distance and number of nearest neighbors for these codes were used as the selection criteria. Many of the multidimensional codes are fully rotationally invariant and give asymptotic coding gains up to 6.0 dB. From the infinite lattice codes, the best codes for transmitting J, J + 1/4, J + 1/3, J + 1/2, J + 2/3, and J + 3/4 bit/sym (J an integer) are presented.

Trace elements in Gem-Quality Diamonds - Origin and evolution of diamond-forming fluid inclusions

NASA Astrophysics Data System (ADS)

Pearson, Graham; Krebs, Mandy; Stachel, Thomas; Woodland, Sarah; Chinn, Ingrid; Kong, Julie

2017-04-01

In the same way that melt inclusions in phenocrysts have expanded our idea of melt formation and evolution in basalts, studying fluids trapped in diamonds is providing important new constraints on the nature of diamond-forming fluids. Fibrous and cloudy diamonds trap a high but variable density of fluid inclusions and so have been extensively studied using major and trace element compositions. In contrast, constraining the nature of the diamond-forming fluid for high purity gem-quality diamonds has been restricted by the rarity of available high quality trace element data. This is due to the extremely low concentrations of impurities that gem diamonds contain - often in the ppt range. The recent discovery of fluids in gem diamonds showing similar major element chemistry to fluid-rich diamonds suggest that many diamonds may share a common spectrum of parental fluids. Here we test this idea further. Recent advances in analytical techniques, in particular the development of the "off-line" laser ablation pre-concentration approach, have allowed fully quantitative trace element data to be recovered from "fluid-poor", high quality gem diamonds. We present trace element data for gem diamonds from a variety of locations from Canada, S. Africa and Russia, containing either silicate or sulphide inclusions to examine possible paragenetic or genetic differences between fluids. REE abundance in the "gem" diamonds vary from 0.1 to 0.0001 x chondrite. To a first order, we observe the same spectrum of trace element compositions in the gem diamonds as that seen in fluid-rich "fibrous" diamonds, supporting a common origin for the fluids. REE patterns range from extremely flat (Ce/Yb)n 2.5 to 5 (commonly in sulphide-bearing diamonds) to >70, the latter having significantly greater inter-element HFSE/LILE fractionation. In general, the fluids from the sulphide-bearing diamonds are less REE-enriched than the silicate-bearing diamonds, but the ranges overlap significantly. The very large range in REE fractionation mimics very closely that produced in high pressure (5-6 GPa) experimental melts of CO2-H2O fluxed peridotite. Hence, the elemental characteristics of the fluids could be reconciled by the diamonds growing from such melts over a range of T and hence F, with the sulphide-bearing diamonds generally being produced by larger fraction (higher T) melts that have reacted less with their wall rocks. It is also possible that the less REE enriched fluids are consistent with derivation from more reduced CH4-bearing fluids that have lower solute capacity than oxidised fluids. This option is being evaluated.

Isotopically Enriched C-13 Diamond Anvil as a Stress Sensor in High Pressure Experiments

NASA Astrophysics Data System (ADS)

Vohra, Yogesh; Qiu, Wei; Kondratyev, Andreiy; Velisavljevic, Nenad; Baker, Paul

2004-03-01

The conventional high pressure diamond anvils were modified by growing an isotopically pure C-13 diamond layer by microwave plasma chemical vapor deposition using methane/hydrogen/oxygen chemistry. The isotopically pure C-13 nature of the culet of the diamond anvil was confirmed by the Raman spectroscopy measurements. This isotopically engineered diamond anvil was used against a natural abundance diamond anvil for high pressure experiments in a diamond anvil cell. Spatial resolved Raman spectroscopy was used to measure the stress induced shift in the C-13 layer as well as the undelying C-12 layer to ultra high pressures. The observed shift and splitiing of the diamond first order Raman spectrum was correlated with the stress distribution in the diamond anvil cell. The experimental results will be compared with the finite element modeling results using NIKE-2D software in order to create a mathematical relationship between sets of the following parameters: vertical (z axis) distance; horizontal (r axis) distance; max shear stress, and pressure. The isotopically enriched diamond anvils offer unique opportunities to measure stress distribution in the diamond anvil cell devices.

Universal holonomic single quantum gates over a geometric spin with phase-modulated polarized light.

PubMed

Ishida, Naoki; Nakamura, Takaaki; Tanaka, Touta; Mishima, Shota; Kano, Hiroki; Kuroiwa, Ryota; Sekiguchi, Yuhei; Kosaka, Hideo

2018-05-15

We demonstrate universal non-adiabatic non-abelian holonomic single quantum gates over a geometric electron spin with phase-modulated polarized light and 93% average fidelity. This allows purely geometric rotation around an arbitrary axis by any angle defined by light polarization and phase using a degenerate three-level Λ-type system in a negatively charged nitrogen-vacancy center in diamond. Since the control light is completely resonant to the ancillary excited state, the demonstrated holonomic gate not only is fast with low power, but also is precise without the dynamical phase being subject to control error and environmental noise. It thus allows pulse shaping for further fidelity.

Electrostatic Fluxes and Plasma Rotation in the Edge Region of EXTRAP-T2R

NASA Astrophysics Data System (ADS)

Serianni, G.; Antoni, V.; Bergsåker, H.; Brunsell, P.; Drake, J. R.; Spolaore, M.; Sätherblom, H. E.; Vianello, N.

2001-10-01

The EXTRAP-T2 reversed field pinch has undergone a significant reconstruction into the new T2R device. This paper reports the first measurements performed with Langmuir probes in the edge region of EXTRAP-T2R. The radial profiles of plasma parameters like electron density and temperature, plasma potential, electrical fields and electrostatic turbulence-driven particle flux are presented. These profiles are interpreted in a momentum balance model where finite Larmor radius losses occur over a distance of about two Larmor radii from the limiter position. The double shear layer of the E×B drift velocity is discussed in terms of the Biglari-Diamond-Terry theory of turbulence decorrelation.

High pressure single-crystal micro X-ray diffraction analysis with GSE_ADA/RSV software

NASA Astrophysics Data System (ADS)

Dera, Przemyslaw; Zhuravlev, Kirill; Prakapenka, Vitali; Rivers, Mark L.; Finkelstein, Gregory J.; Grubor-Urosevic, Ognjen; Tschauner, Oliver; Clark, Simon M.; Downs, Robert T.

2013-08-01

GSE_ADA/RSV is a free software package for custom analysis of single-crystal micro X-ray diffraction (SCμXRD) data, developed with particular emphasis on data from samples enclosed in diamond anvil cells and subject to high pressure conditions. The package has been in extensive use at the high pressure beamlines of Advanced Photon Source (APS), Argonne National Laboratory and Advanced Light Source (ALS), Lawrence Berkeley National Laboratory. The software is optimized for processing of wide-rotation images and includes a variety of peak intensity corrections and peak filtering features, which are custom-designed to make processing of high pressure SCμXRD easier and more reliable.

Alluvial diamond resource potential and production capacity assessment of the Central African Republic

USGS Publications Warehouse

Chirico, Peter G.; Barthelemy, Francis; Ngbokoto, Francois A.

2010-01-01

In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflict concerns. This meeting was supported later in 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberly Process Certification Scheme (KPCS) was ratified and signed by diamond-producing and diamond-importing countries. Over 70 countries were included as members of the KPCS at the end of 2007. To prevent trade in "conflict diamonds" while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging. The objective of this study was (1) to assess the naturally occurring endowment of diamonds in the Central African Republic (potential resources) based on geological evidence, previous studies, and recent field data and (2) to assess the diamond-production capacity and measure the intensity of mining activity. Several possible methods can be used to estimate the potential diamond resource. However, because there is generally a lack of sufficient and consistent data recording all diamond mining in the Central African Republic and because time to conduct fieldwork and accessibility to the diamond mining areas are limited, two different methodologies were used: the volume and grade approach and the content per kilometer approach. Estimates are that approximately 39,000,000 carats of alluvial diamonds remain in the eastern and western zones of the CAR combined. This amount is roughly twice the total amount of diamonds reportedly exported from the Central African Republic since 1931. Production capacity is calculated to be 840,000 carats per year, a number that is nearly twice the 450,000 carats per year reported annually by the Central African Republic. The difference in the two numbers reflects the lack of sufficient data on diamond resource grades, worker productivity, and the number and locations of sites being worked.

In-Situ Chemical Analyses of Mineral Inclusions in Diamonds in Kimberlitic Eclogites From Yakutia

NASA Astrophysics Data System (ADS)

ANAND, M.; MISRA, K. C.; TAYLOR, L. A.; SOBOLEV, N. V.

2001-12-01

Mineral inclusions in diamonds (DIs) are stated to provide P-T-X-t information regarding the formation of the diamonds and the nature of the upper mantle. In an endeavor to further understand the importance of diamonds and their DIs in relation to their host rocks, we have investigated several diamondiferous eclogites from Yakutia, first by HRXC tomography (Taylor et al., 2001, this meeting) and then by dissection of the eclogites into their individual minerals. The mineralogy of the host eclogite is presented by Misra et al. (2001, this meeting). Two of the diamondiferous eclogite xenoliths, although weighing but 66 g and 42 g, contain 74 and 47 macro-diamonds, resp. Based on HRXCT imaging, appropriate sections were selected in the eclogite to extract diamonds with minimum loss of material. In the majority of cases, diamonds occur as perfect octahedron with well developed crystal faces. In some cases, however, diamonds occur as macles (twinned xls). The size range of the diamonds is 1-6 mm. Optical examination reveals the sulfides as the most common DIs in these diamonds, followed by clinopyroxenes and garnets. Each diamond was cut and polished along relatively soft directions parallel to either (001) or (110) faces so as to expose DIs for in-situ analyses. Examination by cathodoluminescence (CL) on an EMP demonstrated that the majority of the diamonds have minute, optically invisible, cracks from the DIs to the surfaces of the diamonds - i.e., the possibility of an open system. These diamonds show complicated growth histories and contain DIs that are in some cases, found to be associated with secondary alteration. In addition, the DIs in each diamond, examined in-situ are of different composition from the host and different from DIs in other diamonds, a relationship reported earlier (Taylor et al., 2000, Int'l Geol Rev). These observations raise serious doubts about the significance of DIs and the pristinity and syngenesis of DIs removed by the typical diamond~crushing procedure. Therefore, extreme caution must be taken when interpreting any of the P-T-X-t conditions of diamond growth, based on DIs.

Genesis of diamond inclusions: An integrated cathodoluminescence (CL) and Electron backscatter diffraction (EBSD) study on eclogitic and peridotitic inclusions and their diamond host.

NASA Astrophysics Data System (ADS)

van den Heuvel, Quint; Matveev, Sergei; Drury, Martyn; Gress, Michael; Chinn, Ingrid; Davies, Gareth

2017-04-01

Diamond inclusions are potentially fundamental to understanding the formation conditions of diamond and the volatile cycles in the deep mantle. In order to fully understand the implications of the compositional information recorded by inclusions it is vital to know whether the inclusions are proto-, syn-, or epigenetic and the extent to which they have equilibrated with diamond forming fluids. In previous studies, the widespread assumption was made that the majority of diamond inclusions are syngenetic, based upon observation of cubo-octahedral morphology imposed on the inclusions. Recent work has reported the crystallographic relationship between inclusions and the host diamond to be highly complex and the lack of crystallographic relationships between inclusions and diamonds has led some to question the significance of imposed cubo-octahedral morphology. This study presents an integrated EBSD and CL study of 9 diamonds containing 20 pyropes, 2 diopsides, 1 forsterite and 1 rutile from the Jwaneng and Letlhakane kimberlite clusters, Botswana. A new method was developed to analyze the crystallographic orientation of the host diamond and the inclusions with EBSD. Diamonds plates were sequentially polished to expose inclusions at different levels in the diamond. CL imaging at different depths was performed in order to produce a 3D view of diamond growth zones around the inclusions. Standard diamond polishing techniques proved too aggressive for silicate inclusions as they were damaged to such a degree that EBSD measurements on the inclusions were impossible. The inclusions were milled with a Ga+ focused ion beam (FIB) at a 12° angle to clean the surface for EBSD measurements. Of the 24 inclusions, 9 have an imposed cubo-octahedral morphology. Of these inclusions, 6 have faces orientated parallel to diamond growth zones and/or appear to have nucleated on a diamond growth surface, implying syngenesis. In contrast, other diamonds record resorption events such that inclusions now cut diamond growth zones. In most cases, the growth zonation around inclusions is not well defined due to CL haloes but some inclusions clearly disrupt diamond growth. Crystallographic orientations of diamond and the inclusions, determined using EBSD, revealed that each inclusion has a homogeneous orientation and record no compositional zonation. The diamonds also showed no angular deviations despite many having multiple growth and resorption zones; implying epitaxial growth of diamond. Crystallographic alignment between diamond and inclusions was not recorded for the principle planes and limited to 3 possible coincidences on minor planes from the 24 inclusions studied. The CL data show no evidence of syngenesis for these 3 inclusions. Analyses of two diamonds with inclusion clusters in different growth zones, 400 µm apart, revealed the same chemical composition and orientation, potentially implying they originated from an original larger inclusion. Combined EBSD and CL data suggest that there is no direct orientational correlation (epitaxial growth) between silicate inclusions and the host diamond, even when the mineral phases are of the same symmetry group. The presentation will provide a detailed evaluation of the genesis of individual inclusions.

Industrial diamond

USGS Publications Warehouse

Olson, D.W.

2013-01-01

Estimated 2012 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2012, natural industrial diamonds were produced in at least 20 countries, and synthetic industrial diamond was produced in at least 12 countries. About 99 percent of the combined natural and synthetic global output was produced in Belarus, China, Ireland, Japan, Russia, South Africa and the United States. During 2012, China was the world’s leading producer of synthetic industrial diamond followed by the United States and Russia. In 2012, the two U.S. synthetic producers, one in Pennsylvania and the other in Ohio, had an estimated output of 103 million carats, valued at about $70.6 million. This was an estimated 43.7 million carats of synthetic diamond bort, grit, and dust and powder with a value of $14.5 million combined with an estimated 59.7 million carats of synthetic diamond stone with a value of $56.1 million. Also in 2012, nine U.S. firms manufactured polycrystalline diamond (PCD) from synthetic diamond grit and powder. The United States government does not collect or maintain data for either domestic PCD producers or domestic chemical vapor deposition (CVD) diamond producers for quantity or value of annual production. Current trade and consumption quantity data are not available for PCD or for CVD diamond. For these reasons, PCD and CVD diamond are not included in the industrial diamond quantitative data reported here.

X-Ray Tomography of Diamondiferous Eclogites: Clues to the Origin of Diamonds.

NASA Astrophysics Data System (ADS)

Taylor, L. A.; Ketcham, R. A.

2009-05-01

During the last decade or so, considerable new and significant data have been gathered concerning the origin of diamonds. This has come from the mantle xenoliths that are the rocks in which the diamonds originated, namely eclogites and peridotites, the host rocks for diamonds in the mantle. Upon rising through the crust to the surface in their kimberlite magmatic carriers and subsequent weathering on the surface, the weak olivine commonly alters, thereby reducing the crushing strength of the peridotite xenoliths. However, the eclogite xenoliths often retain enough toughness to resist total shattering after initial crushing during diamond recovery process. Subjecting these eclogite nodules to X-rays (e.g., 1.54 Å Cu K) can reveal the bright-blue fluorescence of any diamonds exposed at the surface of the xenoliths. Slow and careful extraction can result in recovery of large diamonds. Many of these unique rocks are the ones upon which we have performed High- Resolution X-ray Computed Tomography (HRXCT) at UT Austin. These data have formed the basis for further eclogite dissections and diamond polishing at UT Knoxville. The size of the diamondiferous eclogites that were scanned by HRXCT are from 20 g to 8.8 kg, all with many diamonds ranging from <1 mm to >1 cm, most octahedral, several with mineral inclusions. These diamondiferous eclogites have both textures and fabrics that provide evidence indicating the secondary formation of the diamonds. These include lineations of diamonds along zones of metasomatic alteration, former zones of enhanced permeability; the non-association of sulfides (po, pn, cpy) with the diamonds, versus sulfide-immiscible melt for the diamond origin; lack of any diamonds in direct contact with the primary garnets or clinopyroxenes; and the presence of some dodecahedral diamonds, indicative of resorption processes, typically attributed to the kimberlite melt. Indeed, these eclogites are not igneous in origin, but metamorphic products of their subducted oceanic crustal protoliths. In addition, detailed studies of the extracted diamonds supply more unexpected results. Polished diamonds examined with cathodoluminescence show evidence for a torturous life of cubic nucleation, growth, resorption, octahedral growth, resorption, and even plastic deformation. These are anomalous observations of diamonds supposedly formed along with the primary minerals in their eclogite hosts. The mineral inclusions in the diamonds reveal additional compelling clues of their origin. Multiple clinopyroxene inclusions can have different compositions within a single diamond, different between diamonds, and even different from that of the host. It is proposed that diamonds present in mantle eclogite xenoliths are secondary, having little to do with their hosts, formed by metasomatic fluids penetrating the eclogites along zones of permeability, and causing extensive secondary alteration and even partial melting of the primary garnets and omphacites.

Equations of state and pressure dependence of bulk modulus for aggregated diamond nanorods

NASA Astrophysics Data System (ADS)

Patel, G. R.; Thakar, N. A.; Pandya, T. C.

2018-04-01

In the present paper study of the high pressure behaviour of aggregated diamond nanorods (ADNRs) and diamond have been carried out. A comparative study of different equations of state is discussed to understand the high pressure behaviour of diamond and the aggregated diamond nanorods. In the present study the usual Tait's equation of state has been modified to predict the high pressure behaviour of carbon material ADNRs and diamond. The results obtained in the present study are compared with available experimental evidences. Bulk moduli as a function of pressure are also computed for ADNRs and natural diamond in the light of recent investigations. Present study reveals that ADNRs are less compressible than diamond.

Electron emission from diamond films seeded using kitchen-wrap polyethylene

NASA Astrophysics Data System (ADS)

Varshney, D.; Makarov, V. I.; Saxena, P.; Guinel, M. J. F.; Kumar, A.; Scott, J. F.; Weiner, B. R.; Morell, G.

2011-03-01

Diamond has many potential electronic applications, but the diamond seeding methods are generally harsh on the substrates rendering them unsuitable for integration in electronics. We report a non-abrasive, scalable and economic process of diamond film seeding using kitchen-wrap polyethylene employing hot filament chemical vapour reaction of H2S/CH4/H2 gas mixtures on Cu substrates. The fabricated diamond films were characterized with scanning electron microscopy, transmission electron microscopy and Raman spectroscopy, which confirm that the deposited film consists of a microcrystalline diamond of size in the range 0.5-1.0 µm. The synthesized diamond films exhibit a turn-on field of about 8.5 V µm-1 and long-term stability. Diamond film synthesis using polyethylene will enable the integration of diamond heat sinks into high-power and high-temperature electronic devices.

Drilling of optical glass with electroplated diamond tools

NASA Astrophysics Data System (ADS)

Wang, A. J.; Luan, C. G.; Yu, A. B.

2010-10-01

K9 optical glass drilling experiments were carried out. Bright nickel electroplated diamond tools with small slots and under heat treatment in different temperature were fabricated. Scan electro microscope was applied to analyze the wear of electroplated diamond tool. The material removal rate and grinding ratio were calculated. Machining quality was observed. Bond coating hardness was measured. The experimental results show that coolant is needed for the drilling processes of optical glasses. Heat treatment temperature of diamond tool has influence on wearability of diamond tool and grinding ratio. There were two wear types of electroplated diamond tool, diamond grit wear and bond wear. With the machining processes, wear of diamond grits included fracture, blunt and pull-out, and electroplated bond was gradually worn out. High material removal rates could be obtained by using diamond tool with suitable slot numbers. Bright nickel coating bond presents smallest grains and has better mechanical properties. Bright nickel electroplated diamond tool with slot structure and heat treatment under 200°C was suitable for optical glass drilling.

Microplasma device architectures with various diamond nanostructures

NASA Astrophysics Data System (ADS)

Kunuku, Srinivasu; Jothiramalingam Sankaran, Kamatchi; Leou, Keh-Chyang; Lin, I.-Nan

2017-02-01

Diamond nanostructures (DNSs) were fabricated from three different morphological diamonds, microcrystalline diamond (MCD), nanocrystalline diamond (NCD), and ultrananocrystalline diamond (UNCD) films, using a reactive ion etching method. The plasma illumination (PI) behavior of microplasma devices using the DNSs and the diamond films as cathode were investigated. The Paschen curve approach revealed that the secondary electron emission coefficient (γ value) of diamond materials is similar irrespective of the microstructure (MCD, NCD, and UNCD) and geometry of the materials (DNSs and diamond films). The diamond materials show markedly larger γ-coefficient than conventional metallic cathode materials such as Mo that resulted in markedly better PI behavior for the corresponding microplasma devices. Moreover, the PI behavior, i.e. the voltage dependence of plasma current density (J pl-V), plasma density (n e-V), and the robustness of the devices, varied markedly with the microstructure and geometry of the cathode materials that was closely correlated to the electron field emission (EFE) properties of the cathode materials. The UNCD nanopillars, possessing good EFE properties, resulted in superior PI behavior, whereas the MCD diamond films with insufficient EFE properties led to inferior PI behavior. Consequently, enhancement of plasma characteristics is the collective effects of EFE behavior and secondary electron emission characteristics of diamond-based cathode materials.

Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles

PubMed Central

Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

2016-01-01

A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200 °C for 2 h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000 °C for 1 h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air. PMID:26831205

Enhancement of oxidation resistance via a self-healing boron carbide coating on diamond particles.

PubMed

Sun, Youhong; Meng, Qingnan; Qian, Ming; Liu, Baochang; Gao, Ke; Ma, Yinlong; Wen, Mao; Zheng, Weitao

2016-02-02

A boron carbide coating was applied to diamond particles by heating the particles in a powder mixture consisting of H3BO3, B and Mg. The composition, bond state and coverage fraction of the boron carbide coating on the diamond particles were investigated. The boron carbide coating prefers to grow on the diamond (100) surface than on the diamond (111) surface. A stoichiometric B4C coating completely covered the diamond particle after maintaining the raw mixture at 1200 °C for 2 h. The contribution of the boron carbide coating to the oxidation resistance enhancement of the diamond particles was investigated. During annealing of the coated diamond in air, the priory formed B2O3, which exhibits a self-healing property, as an oxygen barrier layer, which protected the diamond from oxidation. The formation temperature of B2O3 is dependent on the amorphous boron carbide content. The coating on the diamond provided effective protection of the diamond against oxidation by heating in air at 1000 °C for 1 h. Furthermore, the presence of the boron carbide coating also contributed to the maintenance of the static compressive strength during the annealing of diamond in air.

Improvement of the software Bernese for SLR data processing in the Main Metrological Centre of the State Time and Frequency Service

NASA Astrophysics Data System (ADS)

Tsyba, E.; Kaufman, M.

2015-08-01

Preparatory works for resuming operational calculations of the Earth rotation parameters based on the results of satellite laser ranging data processing (LAGEOS 1, LAGEOS 2) are to be completed in the Main Metrology Centre Of The State Time And Frequency Service (VNIIFTRI) in 2014. For this purpose BERNESE 5.2 software (Dach & Walser, 2014) was chosen as a base software which has been used for many years in the Main Metrological Centre of the State Time and Frequency Service to process phase observations of GLONASS and GPS satellites. Although in the BERNESE 5.2 software announced presentation the possibility of the SLR data processing is declared, it has not been fully implemented. In particular there is no such an essential element as corrective action (as input or resulting parameters) in the local time scale ("time bias"), etc. Therefore, additional program blocks have been developed and integrated into the BERNESE 5.2 software environment. The program blocks are written in Perl and Matlab program languages and can be used both for Windows and Linux, 32-bit and 64-bit platforms.

Problems And Their Solutions When Thin-Walled Turned Parts Of High Precision With Quasi-Optical Surfaces Are Manufactured On A CNC Automatic Lathe Under Workshop Conditions

NASA Astrophysics Data System (ADS)

Jaeger, Valentin E.

1989-04-01

The geometrical accuracy and surface roughness of diamond-turned workpieces is influenced by several parameters: the properties of the machine tool, the cutting process and the environmental conditions. A thin-walled electrode made from an aluminium alloy (wall thickness: 1 mm, length: 169 mm, outer diameter: 126 mm) and intended for an electrostatic measuring instrument, serves as an example to show how quasi-optical surfaces with a surface roughness Rα < 10 nm and deviations from roundness of <= 5 μm can be achieved when some of these influence quantities are optimized. The cylindrical part of the electrode was turned by means of a rounded mirror-finish diamond tool, the width of the cutting edge being 2 mm, the rake angle -6° and the clearance angle 2°. Compliance with the tolerances of geometrical accuracy was particularly difficult. As age-hardened wrought aluminium alloys cannot be stress-relieved by annealing, or only insufficiently, the geometrical accuracy - in particular the roundness - of thin-walled, rotationally symmetric bodies decisively depends on the state of stress of the workpiece material, on the clamping fixture and on the balanced condition of this clamping fixture.

Cavitation erosion resistance of diamond-like carbon coating on stainless steel

NASA Astrophysics Data System (ADS)

Cheng, Feng; Jiang, Shuyun

2014-02-01

Two diamond-like carbon (DLC) coatings are prepared on stainless steel 304 by cathodic arc plasma deposition technology at different substrate bias voltages and arc currents (-200 V/80 A, labeled DLC-1, and -100 V/60 A, labeled DLC-2). Cavitation tests are performed by using a rotating-disk test rig to explore the cavitation erosion resistance of the DLC coating. The mass losses, surface morphologies, chemical compositions and the phase constituents of the specimens after cavitation tests are examined by using digital balance, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. The results indicate that the DLC-2 coatings can elongate the incubation period of stainless steel, leading to an excellent cavitation erosion resistance as compared to the untreated stainless steel specimens. After duration of 100 h cavitation test, serious damaged surfaces and plenty of scratches can be observed on the surfaces of the stainless steel specimens, while only a few grooves and tiny pits are observed on the DLC-2 coatings. It is concluded that, decreasing micro defects and increasing adhesion can reduce the delamination of DLC coating, and the erosion continues in the stainless steel substrate after DLC coating failure, and the eroded surface of the substrate is subjected to the combined action from cavitation erosion and slurry erosion.

Cora rotary pump for implantable left ventricular assist device: biomaterial aspects.

PubMed

Montiès, J R; Dion, I; Havlik, P; Rouais, F; Trinkl, J; Baquey, C

1997-07-01

Our group is developing a left ventricular assist device based on the principle of the Maillard-Wankel rotative compressor: it is a rotary, not centrifugal, pump that produces a pulsatile flow. Stringent requirements have been defined for construction materials. They must be light, yet sufficiently hard and rigid, and able to be machined with high precision. The friction coefficient must be low and the wear resistance high. The materials must be chemically inert and not deformable. Also, the materials must be biocompatible, and the blood contacting surface must be hemocompatible. We assessed the materials in terms of physiochemistry, mechanics, and tribology to select the best for hemocompatibility (determined by studies of protein adsorption; platelet, leukocyte, and red cell retention; and hemolysis, among other measurements) and biocompatibility (determined by measurement of complement activation and toxicity, among other criteria). Of the materials tested, for short- and middle-term assistance, we chose titanium alloy (Ti6Al4V) and alumina ceramic (Al2O3) and for long-term and permanent use, composite materials (TiN coating on graphite). We saw that the polishing process of the substrate must be improved. For the future, the best coating material would be diamond-like carbon (DLC) or crystalline diamond coating.

High-Performance Wireless Telemetry

NASA Technical Reports Server (NTRS)

Griebeler, Elmer; Nawash, Nuha; Buckley, James

2011-01-01

Prior technology for machinery data acquisition used slip rings, FM radio communication, or non-real-time digital communication. Slip rings are often noisy, require much space that may not be available, and require access to the shaft, which may not be possible. FM radio is not accurate or stable, and is limited in the number of channels, often with channel crosstalk, and intermittent as the shaft rotates. Non-real-time digital communication is very popular, but complex, with long development time, and objections from users who need continuous waveforms from many channels. This innovation extends the amount of information conveyed from a rotating machine to a data acquisition system while keeping the development time short and keeping the rotating electronics simple, compact, stable, and rugged. The data are all real time. The product of the number of channels, times the bit resolution, times the update rate, gives a data rate higher than available by older methods. The telemetry system consists of a data-receiving rack that supplies magnetically coupled power to a rotating instrument amplifier ring in the machine being monitored. The ring digitizes the data and magnetically couples the data back to the rack, where it is made available. The transformer is generally a ring positioned around the axis of rotation with one side of the transformer free to rotate and the other side held stationary. The windings are laid in the ring; this gives the data immunity to any rotation that may occur. A medium-frequency sine-wave power source in a rack supplies power through a cable to a rotating ring transformer that passes the power on to a rotating set of electronics. The electronics power a set of up to 40 sensors and provides instrument amplifiers for the sensors. The outputs from the amplifiers are filtered and multiplexed into a serial ADC. The output from the ADC is connected to another rotating ring transformer that conveys the serial data from the rotating section to the stationary section. From there, a cable conveys the serial data to the remote rack, where it is reconditioned to logic level specifications, de-serialized, and converted back to analog. In the rotating electronics are code generators to indicate the beginning of files for data synchronization.

31 CFR 592.201 - Prohibited importation and exportation of any rough diamond; permitted importation or exportation...

Code of Federal Regulations, 2011 CFR

2011-07-01

... of any rough diamond; permitted importation or exportation of any rough diamond. 592.201 Section 592... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS Prohibitions § 592.201 Prohibited importation and exportation of any rough diamond; permitted importation or exportation...

31 CFR 592.201 - Prohibited importation and exportation of any rough diamond; permitted importation or exportation...

Code of Federal Regulations, 2012 CFR

2012-07-01

... of any rough diamond; permitted importation or exportation of any rough diamond. 592.201 Section 592... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS Prohibitions § 592.201 Prohibited importation and exportation of any rough diamond; permitted importation or exportation...

31 CFR 592.201 - Prohibited importation and exportation of any rough diamond; permitted importation or exportation...

Code of Federal Regulations, 2013 CFR

2013-07-01

... of any rough diamond; permitted importation or exportation of any rough diamond. 592.201 Section 592... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS Prohibitions § 592.201 Prohibited importation and exportation of any rough diamond; permitted importation or exportation...

31 CFR 592.201 - Prohibited importation and exportation of any rough diamond; permitted importation or exportation...

Code of Federal Regulations, 2014 CFR

2014-07-01

... of any rough diamond; permitted importation or exportation of any rough diamond. 592.201 Section 592... FOREIGN ASSETS CONTROL, DEPARTMENT OF THE TREASURY ROUGH DIAMONDS CONTROL REGULATIONS Prohibitions § 592.201 Prohibited importation and exportation of any rough diamond; permitted importation or exportation...

Nanocrystalline diamond micro-anvil grown on single crystal diamond as a generator of ultra-high pressures

DOE PAGES

Samudrala, Gopi K.; Moore, Samuel L.; Velisavljevic, Nenad; ...

2016-09-29

By combining mask-less lithography and chemical vapor deposition (CVD) techniques, a novel two-stage diamond anvil has been fabricated. A nanocrystalline diamond (NCD) micro-anvil 30 μm in diameter was grown at the center of a [100]-oriented, diamond anvil by utilizing microwave plasma CVD method. The NCD micro-anvil has a diamond grain size of 115 nm and micro-focused Raman and X-ray Photoelectron spectroscopy analysis indicate sp3-bonded diamond content of 72%. Lastly, these CVD grown NCD micro-anvils were tested in an opposed anvil configuration and the transition metals osmium and tungsten were compressed to high pressures of 264 GPa in a diamond anvilmore » cell.« less

Surface Design and Engineering Toward Wear-Resistant, Self-Lubricant Diamond Films and Coatings. Chapter 10

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1999-01-01

This chapter describes three studies on the surface design, surface engineering, and tribology of chemical-vapor-deposited (CVD) diamond films and coatings toward wear-resistant, self-lubricating diamond films and coatings. Friction mechanisms and solid lubrication mechanisms of CVD diamond are stated. Effects of an amorphous hydrogenated carbon on CVD diamond, an amorphous, nondiamond carbon surface layer formed on CVD diamond by carbon and nitrogen ion implantation, and a materials combination of cubic boron nitride and CVD diamond on the adhesion, friction, and wear behaviors of CVD diamond in ultrahigh vacuum are described. How surface modification and the selected materials couple improved the tribological functionality of coatings, giving low coefficient of friction and good wear resistance, is explained.

Mechanical design of thin-film diamond crystal mounting apparatus with optimized thermal contact and crystal strain for coherence preservation x-ray optics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shu, Deming; Shvydko, Yury; Stoupin, Stanislav

A method and mechanical design for a thin-film diamond crystal mounting apparatus for coherence preservation x-ray optics with optimized thermal contact and minimized crystal strain are provided. The novel thin-film diamond crystal mounting apparatus mounts a thin-film diamond crystal supported by a thick chemical vapor deposition (CVD) diamond film spacer with a thickness slightly thicker than the thin-film diamond crystal, and two groups of thin film thermal conductors, such as thin CVD diamond film thermal conductor groups separated by the thick CVD diamond spacer. The two groups of thin CVD film thermal conductors provide thermal conducting interface media with themore » thin-film diamond crystal. A piezoelectric actuator is integrated into a flexural clamping mechanism generating clamping force from zero to an optimal level.« less

Effect of TiO2/Al2O3 film coated diamond abrasive particles by sol-gel technique

NASA Astrophysics Data System (ADS)

Hu, Weida; Wan, Long; Liu, Xiaopan; Li, Qiang; Wang, Zhiqi

2011-04-01

The diamond abrasive particles were coated with the TiO2/Al2O3 film by the sol-gel technique. Compared with the uncoated diamonds, the TiO2/Al2O3 film was excellent material for the protection of the diamonds. The results showed that the incipient oxidation temperature of the TiO2/Al2O3 film coated diamonds in air atmosphere was 775 °C, which was higher 175 °C than that of the uncoated diamonds. And the coated diamonds also had better the diamond's single particle compressive strength and the impact toughness than that of uncoated diamonds after sintering at 750 °C. For the vitrified bond grinding wheels, replacing the uncoated diamonds with the TiO2/Al2O3 film coated diamonds, the volume expansion of the grinding wheels decreased from 6.2% to 3.4%, the porosity decreased from 35.7% to 25.7%, the hardness increased from 61.2HRC to 66.5HRC and the grinding ratio of the vitrified bond grinding wheels to carbide alloy (YG8) increased from 11.5 to 19.1.

Interfacial characteristics of diamond/aluminum composites with high thermal conductivity fabricated by squeeze-casting method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Longtao, E-mail: longtaojiang@163.com; Wang, Pingping; Xiu, Ziyang

2015-08-15

In this work, aluminum matrix composites reinforced with diamond particles (diamond/aluminum composites) were fabricated by squeeze casting method. The material exhibited a thermal conductivity as high as 613 W / (m · K). The obtained composites were investigated by scanning electron microscope and transmission electron microscope in terms of the (100) and (111) facets of diamond particles. The diamond particles were observed to be homogeneously distributed in the aluminum matrix. The diamond{sub (111)}/Al interface was found to be devoid of reaction products. While at the diamond{sub (100)}/Al interface, large-sized aluminum carbides (Al{sub 4}C{sub 3}) with twin-crystal structure were identified. Themore » interfacial characteristics were believed to be responsible for the excellent thermal conductivity of the material. - Graphical abstract: Display Omitted - Highlights: • Squeeze casting method was introduced to fabricate diamond/Al composite. • Sound interfacial bonding with excellent thermal conductivity was produced. • Diamond{sub (111)}/ aluminum interface was firstly characterized by TEM/HRTEM. • Physical combination was the controlling bonding for diamond{sub (111)}/aluminum. • The growth mechanism of Al{sub 4}C{sub 3} was analyzed by crystallography theory.« less

Friction and Wear of Ion-Beam-Deposited Diamondlike Carbon on Chemical-Vapor-Deposited, Fine-Grain Diamond

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa; Wu, Richard L. C.; Lanter, William C.

1996-01-01

Friction and wear behavior of ion-beam-deposited diamondlike carbon (DLC) films coated on chemical-vapor-deposited (CVD), fine-grain diamond coatings were examined in ultrahigh vacuum, dry nitrogen, and humid air environments. The DLC films were produced by the direct impact of an ion beam (composed of a 3:17 mixture of Ar and CH4) at ion energies of 1500 and 700 eV and an RF power of 99 W. Sliding friction experiments were conducted with hemispherical CVD diamond pins sliding on four different carbon-base coating systems: DLC films on CVD diamond; DLC films on silicon; as-deposited, fine-grain CVD diamond; and carbon-ion-implanted, fine-grain CVD diamond on silicon. Results indicate that in ultrahigh vacuum the ion-beam-deposited DLC films on fine-grain CVD diamond (similar to the ion-implanted CVD diamond) greatly decrease both the friction and wear of fine-grain CVD diamond films and provide solid lubrication. In dry nitrogen and in humid air, ion-beam-deposited DLC films on fine-grain CVD diamond films also had a low steady-state coefficient of friction and a low wear rate. These tribological performance benefits, coupled with a wider range of coating thicknesses, led to longer endurance life and improved wear resistance for the DLC deposited on fine-grain CVD diamond in comparison to the ion-implanted diamond films. Thus, DLC deposited on fine-grain CVD diamond films can be an effective wear-resistant, lubricating coating regardless of environment.

Magnetically Orchestrated Formation of Diamond at Lower Temperatures and Pressures

NASA Astrophysics Data System (ADS)

Little, Reginald B.; Lochner, Eric; Goddard, Robert

2005-01-01

Man's curiosity and fascination with diamonds date back to ancient times. The knowledge of the many properties of diamond is recorded during Biblical times. Antoine Lavoisier determined the composition of diamond by burning in O2 to form CO2. With the then existing awareness of graphite as carbon, the race began to convert graphite to diamond. The selective chemical synthesis of diamond has been pursued by Cagniard, Hannay, Moisson and Parson. On the basis of the thermodynamically predicted equilibrium line of diamond and graphite, P W Bridgman attempted extraordinary conditions of high temperature (>2200°C) and pressure (>100,000 atm) for the allotropic conversion of graphite to diamond. H T Hall was the first to successfully form bulk diamond by realizing the kinetic restrictions to Bridgman's (thermodynamic) high pressure high temperature direct allotropic conversion. Moreover, Hall identified catalysts for the faster kinetics of diamond formation. H M Strong determined the import of the liquid catalyst during Hall's catalytic synthesis. W G Eversole discovered the slow metastable low pressure diamond formation by pyrolytic chemical vapor deposition with the molecular hydrogen etching of the rapidly forming stable graphitic carbon. J C Angus determined the import of atomic hydrogen for faster etching for faster diamond growth at low pressure. S Matsumoto has developed plasma and hot filament technology for faster hydrogen and carbon radical generations at low pressure for faster diamond formation. However the metastable low pressure chemical vapor depositions by plasma and hot filament are prone to polycrystalline films. From Bridgman to Hall to Eversole, Angus and Matsumoto, much knowledge has developed of the importance of pressure, temperature, transition metal catalyst, liquid state of metal (metal radicals atoms) and the carbon radical intermediates for diamond synthesis. Here we advance this understanding of diamond formation by demonstrating the external magnetic organization of carbon, metal and hydrogen radicals for lower temperature and pressure synthesis. Here we show that strong static external magnetic field (>15 T) enhances the formation of single crystal diamond at lower pressure and even atmospheric pressure with implications for much better, faster high quality diamond formation by magnetization of current high pressure and temperature technology.

An Overview of High-k Oxides on Hydrogenated-Diamond for Metal-Oxide-Semiconductor Capacitors and Field-Effect Transistors.

PubMed

Liu, Jiangwei; Koide, Yasuo

2018-06-04

Thanks to its excellent intrinsic properties, diamond is promising for applications of high-power electronic devices, ultraviolet detectors, biosensors, high-temperature tolerant gas sensors, etc. Here, an overview of high- k oxides on hydrogenated-diamond (H-diamond) for metal-oxide-semiconductor (MOS) capacitors and MOS field-effect transistors (MOSFETs) is demonstrated. Fabrication routines for the H-diamond MOS capacitors and MOSFETs, band configurations of oxide/H-diamond heterointerfaces, and electrical properties of the MOS and MOSFETs are summarized and discussed. High- k oxide insulators are deposited using atomic layer deposition (ALD) and sputtering deposition (SD) techniques. Electrical properties of the H-diamond MOS capacitors with high- k oxides of ALD-Al₂O₃, ALD-HfO₂, ALD-HfO₂/ALD-Al₂O₃ multilayer, SD-HfO₂/ALD-HfO₂ bilayer, SD-TiO₂/ALD-Al₂O₃ bilayer, and ALD-TiO₂/ALD-Al₂O₃ bilayer are discussed. Analyses for capacitance-voltage characteristics of them show that there are low fixed and trapped charge densities for the ALD-Al₂O₃/H-diamond and SD-HfO₂/ALD-HfO₂/H-diamond MOS capacitors. The k value of 27.2 for the ALD-TiO₂/ALD-Al₂O₃ bilayer is larger than those of the other oxide insulators. Drain-source current versus voltage curves show distinct pitch-off and p -type channel characteristics for the ALD-Al₂O₃/H-diamond, SD-HfO₂/ALD-HfO₂/H-diamond, and ALD-TiO₂/ALD-Al₂O₃/H-diamond MOSFETs. Understanding of fabrication routines and electrical properties for the high- k oxide/H-diamond MOS electronic devices is meaningful for the fabrication of high-performance H-diamond MOS capacitor and MOSFET gas sensors.

Diamonds from Orapa Mine show a clear subduction signature in SIMS stable isotope data

NASA Astrophysics Data System (ADS)

Chinn, Ingrid L.; Perritt, Samantha H.; Stiefenhofer, Johann; Stern, Richard A.

2018-05-01

Spatially resolved analyses reveal considerable isotopic heterogeneity within and among diamonds ranging in size from 0.15 to 4.75 mm from the Orapa Mine, Botswana. The isotopic data are interpreted in conjunction with nitrogen aggregation state data and growth zone relationships from cathodoluminescence images. The integrated information confirms that a distinct diamond growth event (with low IaAB nitrogen aggregation states, moderately high nitrogen contents and δ13C and δ15N values compatible with average mantle values) is younger than the dominant population(s) of Type IaAB diamonds and cores of composite diamonds with more negative and positive δ13C and δ15N values, respectively. A significant proportion of the older diamond generation has high nitrogen contents, well outside the limit sector relationship, and these diamonds are likely to reflect derivation from subducted organic matter. Diamonds with low δ13C values combined with high nitrogen contents and positive δ15N values have not been previously widely recognised, even in studies of diamonds from Orapa. This may have been caused by prior analytical bias towards inclusion-bearing diamonds that are not necessarily representative of the entire range of diamond populations, and because of average measurements from heterogeneous diamonds measured by bulk combustion methods. Two distinct low nitrogen/Type II microdiamond populations were recognised that do not appear to continue into the macrodiamond sizes in the samples studied. Other populations, e.g. those containing residual singly-substituted nitrogen defects, range in size from small microdiamonds to large macrodiamonds. The total diamond content of the Orapa kimberlite thus reflects a complex assortment of multiple diamond populations.

Triphasic Tooling with Small Oriented Diamond Tip for Turning and Smoothing Lightweight Mirrors

NASA Technical Reports Server (NTRS)

Voronov, O. A.; Tompa, G. S.; Kear, B. H.; Veress, V.

2004-01-01

We are developing a new method for the growth of small diamond crystals at very high temperatures and pressures directly from a carbon melt. A prototype "Supercell" has been developed for this purpose. This system is capable of high rate crystal growth in relatively large working volumes. The resulting high quality diamond crystals will be incorporated into a triphasic diamond/titanium carbide/titanium composite tool, with an oriented diamond crystal at its tip. High pressure is needed to prevent degradation of diamond at high temperature, and to ensure the formation of a crack & composite structure. After grinding and polishing, the composite material will be joined to a steel holder, thus forming a diamond-tipped tool for turning and smoothing of a mirror surface. A properly oriented single-crystal diamond cuts and smoothes much better than a conventional polycrystalline diamond crystal. This is because the hardness depends on crystallographic orientation-the difference corresponds to 60-100 GPa on the Knoop scale. Our goal is to achieve surface roughness of about 1 nm, which will be accomplished by precision cutting and smoothing. The hardness of the functionally-graded diamond/titanium carbide/titanium composite tool varies from 100 GPa at its tip to 15 GPa at its base. Previous work has shown that the mass of machined material using an oriented-diamond tool is much larger than that for a standard diamond-metal composite tool.

Diamond MEMS: wafer scale processing, devices, and technology insertion

NASA Astrophysics Data System (ADS)

Carlisle, J. A.

2009-05-01

Diamond has long held the promise of revolutionary new devices: impervious chemical barriers, smooth and reliable microscopic machines, and tough mechanical tools. Yet it's been an outsider. Laboratories have been effectively growing diamond crystals for at least 25 years, but the jump to market viability has always been blocked by the expense of diamond production and inability to integrate with other materials. Advances in chemical vapor deposition (CVD) processes have given rise to a hierarchy of carbon films ranging from diamond-like carbon (DLC) to vapor-deposited diamond coatings, however. All have pros and cons based on structure and cost, but they all share some of diamond's heralded attributes. The best performer, in theory, is the purest form of diamond film possible, one absent of graphitic phases. Such a material would capture the extreme hardness, high Young's modulus and chemical inertness of natural diamond. Advanced Diamond Technologies Inc., Romeoville, Ill., is the first company to develop a distinct chemical process to create a marketable phase-pure diamond film. The material, called UNCD® (for ultrananocrystalline diamond), features grain sizes from 3 to 300 nm in size, and layers just 1 to 2 microns thick. With significant advantages over other thin films, UNCD is designed to be inexpensive enough for use in atomic force microscopy (AFM) probes, microelectromechanical machines (MEMS), cell phone circuitry, radio frequency devices, and even biosensors.

Eclogitic inclusions in diamonds: Evidence of complex mantle processes over time

NASA Astrophysics Data System (ADS)

Taylor, Lawrence A.; Snyder, Gregory A.; Crozaz, Ghislaine; Sobolev, Vladimir N.; Yefimova, Emiliya S.; Sobolev, Nikolai V.

1996-08-01

The first ion-probe trace element analyses of clinopyroxene-garnet pairs both included within diamonds and from the eclogite host xenoliths are reported; these diamondiferous eclogites are from the Udachnaya and Mir kimberlite pipes, Yakutia, Russia. The major and trace element analyses of these diamond-inclusion and host-rock pairs are compared in order to determine the relative ages of the diamonds, confirm or deny genetic relationships between the diamonds and the eclogites, evaluate models of eclogite petrogenesis, and model igneous processes in the mantle before, during, and after diamond formation. The most striking aspect of the chemical compositions of the diamond inclusions is the diversity of relationships with their eclogite hosts. No single distinct pattern of variation from diamond inclusion minerals to host minerals is found for all four samples. Garnet and clinopyroxene inclusions in the diamonds from two samples (U-65/3 and U-66/3) have lower Mg#s, lower Mg, and higher Fe contents, and lower LREE than those in the host eclogite. We interpret such variations as due to metasomatism of the host eclogite after diamond formation. One sample, U-41/3 shows enrichment in diamond-inclusion MREE enrichment relative to the eclogite host and may indicate a metasomatic event prior to, or during, diamond formation. Bulanova [2] found striking differences between inclusions taken from within different portions of the very same diamond. Clinopyroxene inclusions taken from the central (early) portions of Yakutian diamonds were lower in Mg# and Mg contents (by up to 25%) than those later inclusions at the rims of diamonds. These trends are parallel to those between diamond inclusions and host eclogites determined for four of the five samples from the present study and may merely represent changing magmatic and/or P-T conditions in the mantle. Garnet trace element compositions are similar in relative proportions, but variable in abundances, between diamond inclusions and host eclogites. This is probably due to the rapid diffusion of trace elements in garnet under mantle temperatures and consequent alteration of the garnet, and not due to juvenile diamonds 'locking in' source heterogeneities (c.f., [3]). Trace element compositions of clinopyroxenes included in diamonds are generally similar to those in the host eclogite. However, one host clinopyroxene does show enrichment in the LREE compared to that in the inclusion and may be attributed to mantle metasomatism, not related to kimberlite transport. In another eclogite, M-46, the host clinopyroxene is depleted in the LREE and Fe, and enriched in the HREE and Mg, relative to the inclusion and is consistent with partial melting of the eclogite subsequent to diamond formation. Sm/Nd ratios in clinopyroxenes appear to be little affected by these processes for most samples, allowing SmNd isotopic studies to yield important information about ancient protoliths. Eclogitic mineral inclusions in Yakutian diamonds appear consanguineous with the diamonds, a contention supported by the observations of Bulanova [2]. Therefore, ReOs whole-rock and Sm/Nd clinopyroxene age determinations of the Udachnaya eclogites also yield the time of diamond formation, approximately 2.9 Ga [32,33].

16 CFR 23.13 - Disclosure of treatments to diamonds

Code of Federal Regulations, 2010 CFR

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Disclosure of treatments to diamonds 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in § 23.22...

16 CFR 23.13 - Disclosure of treatments to diamonds.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Disclosure of treatments to diamonds. 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds. A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in § 23.22...

15 CFR 30.70 - Violation of the Clean Diamond Trade Act.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 15 Commerce and Foreign Trade 1 2013-01-01 2013-01-01 false Violation of the Clean Diamond Trade... Clean Diamond Trade Act. Public Law 108-19, the Clean Diamond Trade Act (the Act), section 8(c... diamonds, including those with respect to the validation of the Kimberley Process Certificate by the...

15 CFR 30.70 - Violation of the Clean Diamond Trade Act.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 15 Commerce and Foreign Trade 1 2012-01-01 2012-01-01 false Violation of the Clean Diamond Trade... Clean Diamond Trade Act. Public Law 108-19, the Clean Diamond Trade Act (the Act), section 8(c... diamonds, including those with respect to the validation of the Kimberley Process Certificate by the...

15 CFR 30.70 - Violation of the Clean Diamond Trade Act.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 15 Commerce and Foreign Trade 1 2010-01-01 2010-01-01 false Violation of the Clean Diamond Trade... Clean Diamond Trade Act. Public Law 108-19, the Clean Diamond Trade Act (the Act), section 8(c... diamonds, including those with respect to the validation of the Kimberley Process Certificate by the...

16 CFR 23.13 - Disclosure of treatments to diamonds

Code of Federal Regulations, 2011 CFR

2011-01-01

... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Disclosure of treatments to diamonds 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in § 23.22...

16 CFR 23.13 - Disclosure of treatments to diamonds.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Disclosure of treatments to diamonds. 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds. A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in § 23.22...

16 CFR 23.13 - Disclosure of treatments to diamonds.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Disclosure of treatments to diamonds. 23.13... JEWELRY, PRECIOUS METALS, AND PEWTER INDUSTRIES § 23.13 Disclosure of treatments to diamonds. A diamond is a gemstone product. Treatments to diamonds should be disclosed in the manner prescribed in § 23.22...

15 CFR 30.70 - Violation of the Clean Diamond Trade Act.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 15 Commerce and Foreign Trade 1 2014-01-01 2014-01-01 false Violation of the Clean Diamond Trade... Clean Diamond Trade Act. Public Law 108-19, the Clean Diamond Trade Act (the Act), section 8(c... diamonds, including those with respect to the validation of the Kimberley Process Certificate by the...

Diamond nanostructures for drug delivery, bioimaging, and biosensing.

PubMed

Chen, Xianfeng; Zhang, Wenjun

2017-02-06

Diamond features an attractive combination of outstanding mechanical, optical, thermal and electrical properties; tunable surface characteristics; and unprecedented biocompatibility. Additionally, diamond can possess unique nitrogen-vacancy emission centers that are highly photostable and extremely sensitive to magnetic fields, temperatures, ion concentrations, and spin densities. With these inherent merits, diamond in various nanoscale configurations has demonstrated a variety of distinctive applications in a broad range of fields. In particular, research on diamond nanoparticles (0-dimensional structures) and arrays of diamond nanoneedles/nanowires (1-dimensional structures) has witnessed important and exciting progress in recent years. Here, we systematically review the superior properties of diamond nanomaterials and the nitrogen-vacancy centers they contain as well as their uses in biomedical applications, including biosensing, bioimaging and drug delivery. Moreover, systematic studies of the biocompatibility and toxicity of diamond nanostructures, which constitute an important issue for the biomedical applications of diamond that has not yet been thoroughly addressed in previous reviews, are also discussed. Finally, we present our insights into the key issues concerning these diamond nanomaterials and their future development for applications.

Diamond network: template-free fabrication and properties.

PubMed

Zhuang, Hao; Yang, Nianjun; Fu, Haiyuan; Zhang, Lei; Wang, Chun; Huang, Nan; Jiang, Xin

2015-03-11

A porous diamond network with three-dimensionally interconnected pores is of technical importance but difficult to be produced. In this contribution, we demonstrate a simple, controllable, and "template-free" approach to fabricate diamond networks. It combines the deposition of diamond/β-SiC nanocomposite film with a wet-chemical selective etching of the β-SiC phase. The porosity of these networks was tuned from 15 to 68%, determined by the ratio of the β-SiC phase in the composite films. The electrochemical working potential and the reactivity of redox probes on the diamond networks are similar to those of a flat nanocrystalline diamond film, while their surface areas are hundreds of times larger than that of a flat diamond film (e.g., 490-fold enhancement for a 3 μm thick diamond network). The marriage of the unprecedented physical/chemical features of diamond with inherent advantages of the porous structure makes the diamond network a potential candidate for various applications such as water treatment, energy conversion (batteries or fuel cells), and storage (capacitors), as well as electrochemical and biochemical sensing.

Effects of protein inter-layers on cell-diamond FET characteristics.

PubMed

Rezek, Bohuslav; Krátká, Marie; Kromka, Alexander; Kalbacova, Marie

2010-12-15

Diamond is recognized as an attractive material for merging solid-state and biological systems. The advantage of diamond field-effect transistors (FET) is that they are chemically resistant, bio-compatible, and can operate without gate oxides. Solution-gated FETs based on H-terminated nanocrystalline diamond films exhibiting surface conductivity are employed here for studying effects of fetal bovine serum (FBS) proteins and osteoblastic SAOS-2 cells on diamond electronic properties. FBS proteins adsorbed on the diamond FETs permanently decrease diamond conductivity as reflected by the -45 mV shift of the FET transfer characteristics. Cell cultivation for 2 days results in a further shift by another -78 mV. We attribute it to a change of diamond material properties rather than purely to the field-effect. Increase in gate leakage currents (by a factor of 4) indicates that the FBS proteins also decrease the diamond-electrolyte electronic barrier induced by C-H surface dipoles. We propose a model where the proteins replace ions in the very vicinity of the H-terminated diamond surface. Copyright © 2010 Elsevier B.V. All rights reserved.

Experimental investigation and statistical modeling of temperature rise in rotary ultrasonic bone drilling.

PubMed

Gupta, Vishal; Pandey, Pulak M

2016-11-01

Thermal necrosis is one of the major problems associated with the bone drilling process in orthopedic/trauma surgical operations. To overcome this problem a new bone drilling method has been introduced recently. Studies have been carried out with rotary ultrasonic drilling (RUD) on pig bones using diamond coated abrasive hollow tools. In the present work, influence of process parameters (rotational speed, feed rate, drill diameter and vibrational amplitude) on change in the temperature was studied using design of experiment technique i.e., response surface methodology (RSM) and data analysis was carried out using analysis of variance (ANOVA). Temperature was recorded and measured by using embedded thermocouple technique at a distance of 0.5mm, 1.0mm, 1.5mm and 2.0mm from the drill site. Statistical model was developed to predict the maximum temperature at the drill tool and bone interface. It was observed that temperature increased with increase in the rotational speed, feed rate and drill diameter and decreased with increase in the vibrational amplitude. Copyright © 2016 IPEM. Published by Elsevier Ltd. All rights reserved.

Computational algorithms dealing with the classical and statistical mechanics of celestial scale polymers in space elevator technology

NASA Astrophysics Data System (ADS)

Knudsen, Steven; Golubovic, Leonardo

Prospects to build Space Elevator (SE) systems have become realistic with ultra-strong materials such as carbon nano-tubes and diamond nano-threads. At cosmic length-scales, space elevators can be modeled as polymer like floppy strings of tethered mass beads. A new venue in SE science has emerged with the introduction of the Rotating Space Elevator (RSE) concept supported by novel algorithms discussed in this presentation. An RSE is a loopy string reaching into outer space. Unlike the classical geostationary SE concepts of Tsiolkovsky, Artsutanov, and Pearson, our RSE exhibits an internal rotation. Thanks to this, objects sliding along the RSE loop spontaneously oscillate between two turning points, one of which is close to the Earth whereas the other one is in outer space. The RSE concept thus solves a major problem in SE technology which is how to supply energy to the climbers moving along space elevator strings. The investigation of the classical and statistical mechanics of a floppy string interacting with objects sliding along it required development of subtle computational algorithms described in this presentation

Design, Fabrication, Optical Testing, and Performance of Diamond Machined Aspheric Mirrors for Ground-Based Near-IR Astronomy

NASA Technical Reports Server (NTRS)

Ohl, Raymond G.; Mink, Ronald; Chambers, V. John; Connelly, Joseph A.; Mentzell, J. Eric; Tveekrem, June L.; Howard, Joseph M.; Preuss, Werner; Schroeder, Mechthild; Sohn, Alex;

Ultrafast transformation of graphite to diamond: an ab initio study of graphite under shock compression.

PubMed

Mundy, Christopher J; Curioni, Alessandro; Goldman, Nir; Will Kuo, I-F; Reed, Evan J; Fried, Laurence E; Ianuzzi, Marcella

2008-05-14

We report herein ab initio molecular dynamics simulations of graphite under shock compression in conjunction with the multiscale shock technique. Our simulations reveal that a novel short-lived layered diamond intermediate is formed within a few hundred of femtoseconds upon shock loading at a shock velocity of 12 kms (longitudinal stress>130 GPa), followed by formation of cubic diamond. The layered diamond state differs from the experimentally observed hexagonal diamond intermediate found at lower pressures and previous hydrostatic calculations in that a rapid buckling of the graphitic planes produces a mixture of hexagonal and cubic diamond (layered diamond). Direct calculation of the x-ray absorption spectra in our simulations reveals that the electronic structure of the final state closely resembles that of compressed cubic diamond.

In vitro assessment of cutting efficiency and durability of zirconia removal diamond rotary instruments.

PubMed

Kim, Joon-Soo; Bae, Ji-Hyeon; Yun, Mi-Jung; Huh, Jung-Bo

2017-06-01

Recently, zirconia removal diamond rotary instruments have become commercially available for efficient cutting of zirconia. However, research of cutting efficiency and the cutting characteristics of zirconia removal diamond rotary instruments is limited. The purpose of this in vitro study was to assess and compare the cutting efficiency, durability, and diamond rotary instrument wear pattern of zirconia diamond removal rotary instruments with those of conventional diamond rotary instruments. In addition, the surface characteristics of the cut zirconia were assessed. Block specimens of 3 mol% yttrium cation-doped tetragonal zirconia polycrystal were machined 10 times for 1 minute each using a high-speed handpiece with 6 types of diamond rotary instrument from 2 manufacturers at a constant force of 2 N (n=5). An electronic scale was used to measure the lost weight after each cut in order to evaluate the cutting efficiency. Field emission scanning electron microscopy was used to evaluate diamond rotary instrument wear patterns and machined zirconia block surface characteristics. Data were statistically analyzed using the Kruskal-Wallis test, followed by the Mann-Whitney U test (α=.05). Zirconia removal fine grit diamond rotary instruments showed cutting efficiency that was reduced compared with conventional fine grit diamond rotary instruments. Diamond grit fracture was the most dominant diamond rotary instrument wear pattern in all groups. All machined zirconia surfaces were primarily subjected to plastic deformation, which is evidence of ductile cutting. Zirconia blocks machined with zirconia removal fine grit diamond rotary instruments showed the least incidence of surface flaws. Although zirconia removal diamond rotary instruments did not show improved cutting efficiency compared with conventional diamond rotary instruments, the machined zirconia surface showed smoother furrows of plastic deformation and fewer surface flaws. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Physical and Tribological Characteristics of Ion-Implanted Diamond Films

NASA Technical Reports Server (NTRS)

Miyoshi, K.; Heidger, S.; Korenyi-Both, A. L.; Jayne, D. T.; Herrera-Fierro, P.; Shogrin, B.; Wilbur, P. J.; Wu, R. L. C.; Garscadden, A.; Barnes, P. N.

1994-01-01

Unidirectional sliding friction experiments were conducted with a natural, polished diamond pin in contact with both as-deposited and carbon-ion-implanted diamond films in ultrahigh vacuum. Diamond films were deposited on silicon, silicon carbide, and silicon nitride by microwave-plasma-assisted chemical vapor deposition. The as-deposited diamond films were impacted with carbon ions at an accelerating energy of 60 keV and a current density of 50 micron A/cm(exp 2) for approximately 6 min, resulting in a dose of 1.2 x 10(exp 17) carbon ions/cm(exp 2). The results indicate that the carbon ion implantation produced a thin surface layer of amorphous, nondiamond carbon. The nondiamond carbon greatly decreased both friction and wear of the diamond films. The coefficients of friction for the carbon-ion-implanted, fine-grain diamond films were less than 0.1, factors of 20 to 30 lower than those for the as-deposited, fine-grain diamond films. The coefficients of friction for the carbon-ion-implanted, coarse-grain diamond films were approximately 0.35, a factor of five lower than those for the as-deposited, coarse-grain diamond films. The wear rates for the carbon-ion-implanted, diamond films were on the order of 10(exp -6) mm(exp 3)/Nm, factors of 30 to 80 lower than that for the as-deposited diamond films, regardless of grain size. The friction of the carbon-ion-implanted diamond films was greatly reduced because the amorphous, nondiamond carbon, which had a low shear strength, was restricted to the surface layers (less than 0.1 micron thick) and because the underlying diamond materials retained their high hardness. In conclusion, the carbon-ion-implanted, fine-grain diamond films can be used effectively as wear resistant, self-lubricating coatings for ceramics, such as silicon nitride and silicon carbide, in ultrahigh vacuum.

32-Bit-Wide Memory Tolerates Failures

NASA Technical Reports Server (NTRS)

Buskirk, Glenn A.

1990-01-01

Electronic memory system of 32-bit words corrects bit errors caused by some common type of failures - even failure of entire 4-bit-wide random-access-memory (RAM) chip. Detects failure of two such chips, so user warned that ouput of memory may contain errors. Includes eight 4-bit-wide DRAM's configured so each bit of each DRAM assigned to different one of four parallel 8-bit words. Each DRAM contributes only 1 bit to each 8-bit word.

Origins of diamond-forming fluids: An isotopic and trace element study of diamonds and silicates from diamondiferous xenoliths

NASA Astrophysics Data System (ADS)

Laiginhas, Fernando; Pearson, D. Graham; McNeill, John; Gurney, John; Nowell, Geoff; Ottley, Chris

2010-05-01

While there is increasing understanding of the age of formation and nature of "gem" diamonds, significant debate revolves around the nature of the fluids/melts from which they form. Stable C and N isotopes have been shown to be highly variable and yet the role of subduction-related fluids remains strongly debated. Recent studies on fibrous diamonds have yielded new trace and major element data (e.g., Weiss et al., 2009) that, together with new radiogenic isotope data (Klein BenDavid et al., 2010) indicate such diamonds grow from fluids that comprise mixtures of hydrous silicic, hydrous saline and carbonatitic fluids, derived from different source components of asthenospheric and lithospheric origin. However, until now such data has been lacking from gem diamonds. Using a new laser-based technique (McNeill et al., 2009), we have analysed a suite of diamonds plus co-existing host silicates from several diamondiferous xenoliths (6 harzburgites, 1 eclogite) from the Finsch and Newlands kimberlites in order to try to understand the fluid compositions that produce gem diamonds and better understand their effects of their mantle wall rocks. Diamonds from the xenoliths show a wide variety of trace element enrichment levels. While the eclogitic diamond shows similar trace element systematics to some of the harzburgitic diamonds there are significant differences within the harzburgitic diamonds from different xenoliths, with those from Finsch being significantly enriched in Ba, Sr and Pb relative to other elements. Nd isotope data on the host silicates is variable and dominantly unradiogenic, indicative of long-term enrichment typically associated with the source of some diamond-forming fluids. We will present Sr isotopic data on host silicates and diamond fluids to constrain whether the "gem" diamonds require the complex sources of fluids that characterise the growth of fibrous diamonds. 1) Y. Weiss, R. Kessel, W.L. Griffin, I. Kiflawi, O. Klein-BenDavid, D.R. Bell, J.W. Harris and O. Navon (2009). A new model for the evolution of diamond-forming fluids: Evidence from microinclusion-bearing diamonds from Kankan, Guinea. Lithos 112, Supp. 2: 660-674. 2) O. Klein-BenDavid, D.G. Pearson, G.M. Nowell, C. Ottley, J.C.R. McNeill, P. Cartigny (2010). Mixed fluid sources involved in diamond growth constrained by Sr-Nd-Pb-C-N isotopes and trace elements. EPSL 289, 1-2: 123-133. 3) J. McNeill, D.G. Pearson, O. Klein-BenDavid, G.M. Nowell, C.J. Ottley and I. Chinn (2009). Quantitative analysis of trace element concentrations in some gem-quality diamonds. J. Phys.: Condens. Matter 21: 364207 (13pp).

Study of diamond film growth and properties

NASA Technical Reports Server (NTRS)

Albin, Sacharial

1990-01-01

The objective was to study diamond film growth and its properties in order to enhance the laser damage threshold of substrate materials. Calculations were performed to evaluate laser induced thermal stress parameter, R(sub T) of diamond. It is found that diamond has several orders of magnitude higher in value for R(sub T) compared to other materials. Thus, the laser induced damage threshold (LIDT) of diamond is much higher. Diamond films were grown using a microwave plasma enhanced chemical vapor deposition (MPECVD) system at various conditions of gas composition, pressure, temperature, and substrate materials. A 0.5 percent CH4 in H2 at 20 torr were ideal conditions for growing of high quality diamond films on substrates maintained at 900 C. The diamond films were polycrystalline which were characterized by scanning electron microscopy (SEM) and Raman scattering spectroscopy. The top surface of the growing film is always rough due to the facets of polycrystalline film while the back surface of the film replicates the substrate surface. An analytical model based on two dimensional periodic heat flow was developed to calculate the effective in-plane (face parallel) diffusivity of a two layer system. The effective diffusivity of diamond/silicon samples was measured using a laser pulse technique. The thermal conductivity of the films was measured to be 13.5 W/cm K, which is better than that of a type Ia natural diamond. Laser induced damage experiments were performed on bare Si substrates, diamond film coated Si, and diamond film windows. Significant improvements in the LIDT were obtained for diamond film coated Si compared to the bare Si.

Enhancement of structure images of interstellar diamond microcrystals by image processing

NASA Technical Reports Server (NTRS)

O'Keefe, Michael A.; Hetherington, Crispin; Turner, John; Blake, David; Freund, Friedemann

1988-01-01

Image processed high resolution TEM images of diamond crystals found in oxidized acid residues of carbonaceous chondrites are presented. Two models of the origin of the diamonds are discussed. The model proposed by Lewis et al. (1987) supposes that the diamonds formed under low pressure conditions, whereas that of Blake et al (1988) suggests that the diamonds formed due to particle-particle collisions behind supernova shock waves. The TEM images of the diamond presented support the high pressure model.

The impact of diamond nanocrystallinity on osteoblast functions.

PubMed

Yang, Lei; Sheldon, Brian W; Webster, Thomas J

2009-07-01

Nanocrystalline diamond has been proposed as an anti-abrasive film on orthopedic implants. In this study, osteoblast (bone forming cells) functions including adhesion (up to 4h), proliferation (up to 5 days) and differentiation (up to 21 days) on different diamond film topographies were systematically investigated. In order to exclude interferences from changes in surface chemistry and wettability (energy), diamond films with nanometer and micron scale topographies were fabricated through microwave plasma enhanced chemical-vapor-deposition and hydrogen plasma treatment. Scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy and water contact angle measurements verified the similar surface chemistry and wettability but varied topographies for all of the diamond films prepared on silicon in this study. Cytocompatibility assays demonstrated enhanced osteoblast functions (including adhesion, proliferation, intracellular protein synthesis, alkaline phosphatase activity and extracellular calcium deposition) on nanocrystalline diamond compared to submicron diamond grain size films for all time periods tested up to 21 days. An SEM study of osteoblast attachment helped to explain the topographical impact diamond had on osteoblast functions by showing altered filopodia extensions on the different diamond topographies. In summary, these results provided insights into understanding the role diamond nanotopography had on osteoblast interactions and more importantly, the application of diamond films to improve orthopedic implant lifetimes.

Friction and wear of plasma-deposited diamond films

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa; Wu, Richard L. C.; Garscadden, Alan; Barnes, Paul N.; Jackson, Howard E.

1993-01-01

Reciprocating sliding friction experiments in humid air and in dry nitrogen and unidirectional sliding friction experiments in ultrahigh vacuum were conducted with a natural diamond pin in contact with microwave-plasma-deposited diamond films. Diamond films with a surface roughness (R rms) ranging from 15 to 160 nm were produced by microwave-plasma-assisted chemical vapor deposition. In humid air and in dry nitrogen, abrasion occurred when the diamond pin made grooves in the surfaces of diamond films, and thus the initial coefficients of friction increased with increasing initial surface roughness. The equilibrium coefficients of friction were independent of the initial surface roughness of the diamond films. In vacuum the friction for diamond films contacting a diamond pin arose primarily from adhesion between the sliding surfaces. In these cases, the initial and equilibrium coefficients of friction were independent of the initial surface roughness of the diamond films. The equilibrium coefficients of friction were 0.02 to 0.04 in humid air and in dry nitrogen, but 1.5 to 1.8 in vacuum. The wear factor of the diamond films depended on the initial surface roughness, regardless of environment; it increased with increasing initial surface roughness. The wear factors were considerably higher in vacuum than in humid air and in dry nitrogen.

19 CFR 12.152 - Prohibitions and conditions on the importation and exportation of rough diamonds.

Code of Federal Regulations, 2014 CFR

2014-04-01

... exportation of rough diamonds. 12.152 Section 12.152 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... rough diamonds. (a) General. The Clean Diamond Trade Act (Pub. L. 108-19) requires the President... States, of any rough diamond, from whatever source, that has not been controlled through the Kimberley...

Electrical Conductivity Of Diamond Up To 1,200 Degrees C

NASA Technical Reports Server (NTRS)

Vandersande, Jan W.; Zoltan, Leslie D.

1993-01-01

Report discusses measurements of electrical conductivities of two synthetic diamond films, three synthetic diamondlike films, and two natural type IIa diamonds at temperatures from ambient to 1,200 degrees C. Measurements performed to compare electrical conductivities of state-of-the-art diamond films with those of natural insulating diamond, particularly at temperatures above 700 degrees C.

Fabrication of diamond based sensors for use in extreme environments

DOE PAGES

Samudrala, Gopi K.; Moore, Samuel L.; Vohra, Yogesh K.

2015-04-23

Electrical and magnetic sensors can be lithographically fabricated on top of diamond substrates and encapsulated in a protective layer of chemical vapor deposited single crystalline diamond. This process when carried out on single crystal diamond anvils employed in high pressure research is termed as designer diamond anvil fabrication. These designer diamond anvils allow researchers to study electrical and magnetic properties of materials under extreme conditions without any possibility of damaging the sensing elements. We describe a novel method for the fabrication of designer diamond anvils with the use of maskless lithography and chemical vapor deposition in this paper. This methodmore » can be utilized to produce diamond based sensors which can function in extreme environments of high pressures, high and low temperatures, corrosive and high radiation conditions. Here, we demonstrate applicability of these diamonds under extreme environments by performing electrical resistance measurements during superconducting transition in rare earth doped iron-based compounds under high pressures to 12 GPa and low temperatures to 10 K.« less

Fabrication of diamond based sensors for use in extreme environments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samudrala, Gopi K.; Moore, Samuel L.; Vohra, Yogesh K.

Electrical and magnetic sensors can be lithographically fabricated on top of diamond substrates and encapsulated in a protective layer of chemical vapor deposited single crystalline diamond. This process when carried out on single crystal diamond anvils employed in high pressure research is termed as designer diamond anvil fabrication. These designer diamond anvils allow researchers to study electrical and magnetic properties of materials under extreme conditions without any possibility of damaging the sensing elements. We describe a novel method for the fabrication of designer diamond anvils with the use of maskless lithography and chemical vapor deposition in this paper. This methodmore » can be utilized to produce diamond based sensors which can function in extreme environments of high pressures, high and low temperatures, corrosive and high radiation conditions. Here, we demonstrate applicability of these diamonds under extreme environments by performing electrical resistance measurements during superconducting transition in rare earth doped iron-based compounds under high pressures to 12 GPa and low temperatures to 10 K.« less

Laser patterning of diamond films

NASA Astrophysics Data System (ADS)

Narayan, J.; Chen, X.

1992-04-01

Selective deposition and fine-scale patterning of hot filament deposited diamond films by the use of pulsed laser irradiation on silicon and copper substrates are reported. The substrates were abraded with diamond and alumina powders before hot-filament chemical vapor deposition. A drastic enhancement in diamond nucleation (using hot-filament chemical vapor deposition) was observed on specimens treated with diamond powder, whereas enhancement on specimens pretreated with alumina powder was relatively insignificant. It is found that the seeding of diamond crystals was substantially reduced by pulsed laser annealing/melting which removes the plastic damage as well as the seed crystals introduced by diamond powder pretreatment. The selective deposition or fine-scale patterning of diamond films was achieved either by a shadow masking or by scanning a focused laser beam to generate desired patterns. The nucleation can also be enhanced by laser deposition of thin films, such as diamond-like carbon and tungsten carbide (WC), and selective deposition and patterning achieved by controlled removal or deposition of the above films.

Effect of Minor Titanium Addition on Copper/Diamond Composites Prepared by Hot Forging

NASA Astrophysics Data System (ADS)

Yang, Fei; Sun, Wei; Singh, Ajit; Bolzoni, Leandro

2018-03-01

Copper/diamond composites have great potential to lead the next generation of advanced heat sink materials for use in high-power electronic devices and high-density integrated circuits because of their potential excellent properties of high thermal conductivity and close thermal expansion to the chip materials (e.g., Si, InP, GaAs). However, the poor wettability between copper and diamond presents a challenge for synthesizing copper/diamond composites with effective metallurgical bonding and satisfied thermal performance. In this article, copper/diamond composites were successfully prepared by hot forging of elemental copper and artificial diamond powders with small amounts (0 vol.%, 3 vol.% and 5 vol.%) of titanium additives. Microstructure observation and mechanical tests showed that adding minor titanium additions in the copper/diamond composite resulted in fewer cracks in the composites' microstructure and significantly improved the bonding between the copper and diamond. The strongest bonding strength was achieved for the copper/diamond composite with 3 vol.% titanium addition, and the possible reasons were discussed.

Cathodoluminescence of diamond as an indicator of its metamorphic history

NASA Astrophysics Data System (ADS)

Kopylova, Maya; Bruce, Loryn; Longo, Micaela; Ryder, John; Dobrzhinetskaya, Larissa

2010-05-01

Diamond displays a supreme resistance to chemical and mechanical weathering, ensuring its survival through complex and prolonged crustal processes, including metamorphism and exhumation. For these reasons, volcanic sources and secondary and tertiary collectors for detrital placer diamonds, like Ural or Bingara diamonds, may be difficult to determine. If metamorphic processes leave their marks on diamond, they can be used to reconstruct crustal geologic processes and ages of primary diamondiferous volcanics. Four diamond suites extracted from metamorphic rocks have been characterized using optical CL, infrared and CL spectroscopy, and photoluminescence at the liquid nitrogen temperature. The studied diamonds are from the ~2.7 Ga sedimentary conglomerate and lamprophyric breccia metamorphosed in the greenschist facies (Wawa, Northern Ontario, Canada) during the 2.67 Ga Kenoran orogeny, and from the ultra-high pressure (UHP) terranes of Kokchetav (Kazakhstan) and Erzgebirge (Germany) exhumated in the Paleozoic. Wawa diamonds (Type IaAB and Type II) displayed green, yellow, orange, and red CL colours controlled by the CL emittance at 520, 576 nm, and between 586 and 664 nm. The UHP terranes diamonds show much weaker CL; few luminescent stones display CL peaks at 395, 498, 528 nm and a broad band at 580-668 nm. In contrast, most common diamonds found in unmetamorphosed rocks, i.e. octahedrally grown Type IaAB stones, luminescence blue emitting light at ~415-440 nm and 480-490 nm. There is a noticeable difference between cathodoluminescence of these diamonds and diamonds in metamorphic rocks. The studied diamonds that experienced metamorphism show a shift of CL emission to longer wavelengths (above 520 nm) and to green, yellow and red CL colours. Photoluminescence has the high resolution necessary to assign luminescence to specific optical centers of diamond. Diamonds in metamorphic rocks contain H3 (pairs of substitutional nitrogen atoms separated by a vacancy) and NVo optical centers (neutrally charged complexes of a vacancy and a single nitrogen). We ascribe the effect of metamorphism on the diamond CL to low-T, low-P deformation that creates lattice dislocations and vacancies. These combine with substitutional N to make and enhance optical centers. The metamorphism-induced CL anneals when diamonds are stored at high-T mantle conditions, as the mobility of dislocations at T>750oC quenches the luminescence. Indeed, all studied diamonds that displayed unusual green, yellow and red CL were found in low and medium grade metamorphic rocks, i.e. Wawa greenschists (T<350oC and P< 3 kb) and Kokchetav and Erzgebirge UHP terranes retrograded in the amphibolite facies (T<750oC, P<14 kb) Our study suggest that a low abundance of octahedrally grown Type IaAB diamonds with blue CL colours among detrital diamonds may indicate that the stones may have once been a part of a low- or medium-grade metamorphic terrane. The CL characteristics superimposed by metamorphism could survive through billions of years of the geological history if not annealed by a high -T process. The discovered record of metamorphism in the diamond crystal lattice provides an opportunity for a better reconstruction of the crustal history and provenance studies of diamond.

Alluvial diamond resource potential and production capacity assessment of Mali

USGS Publications Warehouse

Chirico, Peter G.; Barthelemy, Francis; Kone, Fatiaga

2010-01-01

In May of 2000, a meeting was convened in Kimberley, South Africa, and attended by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that rough, exported diamonds were free of conflictual concerns. This meeting was supported later in 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberley Process Certification Scheme (KPCS) was ratified and signed by diamond-producing and diamond-importing countries. Over 70 countries were included as members of the KPCS at the end of 2007. To prevent trade in "conflict diamonds" while protecting legitimate trade, the KPCS requires that each country set up an internal system of controls to prevent conflict diamonds from entering any imported or exported shipments of rough diamonds. Every diamond or diamond shipment must be accompanied by a Kimberley Process (KP) certificate and be contained in tamper-proof packaging. The objective of this study was (1) to assess the naturally occurring endowment of diamonds in Mali (potential resources) based on geological evidence, previous studies, and recent field data and (2) to assess the diamond-production capacity and measure the intensity of mining activity. Several possible methods can be used to estimate the potential diamond resource. However, because there is generally a lack of sufficient and consistent data recording all diamond mining in Mali and because time to conduct fieldwork and accessibility to the diamond mining areas are limited, four different methodologies were used: the cylindrical calculation of the primary kimberlitic deposits, the surface area methodology, the volume and grade approach, and the content per kilometer approach. Approximately 700,000 carats are estimated to be in the alluvial deposits of the Kenieba region, with 540,000 carats calculated to lie within the concentration grade deposits. Additionally, 580,000 carats are estimated to have been released from the primary kimberlites in the region. Therefore, the total estimated diamond resources in the Kenieba region are thought to be nearly 1,300,000 carats. The Bougouni zones are estimated to have 1,000,000 carats with more than half, 630,000 carats, contained in concentrated deposits. When combined, the Kenieba and Bougouni regions of Mali are estimated to be host to 2,300,000 carats of diamonds.

Diamonds in ophiolites: Contamination or a new diamond growth environment?

NASA Astrophysics Data System (ADS)

Howell, D.; Griffin, W. L.; Yang, J.; Gain, S.; Stern, R. A.; Huang, J.-X.; Jacob, D. E.; Xu, X.; Stokes, A. J.; O'Reilly, S. Y.; Pearson, N. J.

2015-11-01

For more than 20 years, the reported occurrence of diamonds in the chromites and peridotites of the Luobusa massif in Tibet (a complex described as an ophiolite) has been widely ignored by the diamond research community. This skepticism has persisted because the diamonds are similar in many respects to high-pressure high-temperature (HPHT) synthetic/industrial diamonds (grown from metal solvents), and the finding previously has not been independently replicated. We present a detailed examination of the Luobusa diamonds (recovered from both peridotites and chromitites), including morphology, size, color, impurity characteristics (by infrared spectroscopy), internal growth structures, trace-element patterns, and C and N isotopes. A detailed comparison with synthetic industrial diamonds shows many similarities. Cubo-octahedral morphology, yellow color due to unaggregated nitrogen (C centres only, Type Ib), metal-alloy inclusions and highly negative δ13C values are present in both sets of diamonds. The Tibetan diamonds (n = 3) show an exceptionally large range in δ15N (-5.6 to + 28.7 ‰) within individual crystals, and inconsistent fractionation between {111} and {100} growth sectors. This in contrast to large synthetic HPHT diamonds grown by the temperature gradient method, which have with δ15N = 0 ‰ in {111} sectors and + 30 ‰ in {100} sectors, as reported in the literature. This comparison is limited by the small sample set combined with the fact the diamonds probably grew by different processes. However, the Tibetan diamonds do have generally higher concentrations and different ratios of trace elements; most inclusions are a NiMnCo alloy, but there are also some small REE-rich phases never seen in HPHT synthetics. These characteristics indicate that the Tibetan diamonds grew in contact with a C-saturated Ni-Mn-Co-rich melt in a highly reduced environment. The stable isotopes indicate a major subduction-related contribution to the chemical environment. The unaggregated nitrogen, combined with the lack of evidence for resorption or plastic deformation, suggests a short (geologically speaking) residence in the mantle. Previously published models to explain the occurrence of the diamonds, and other phases indicative of highly reduced conditions and very high pressures, have failed to take into account the characteristics of the diamonds and the implications for their formation. For these diamonds to be seriously considered as the result of a natural growth environment requires a new understanding of mantle conditions that could produce them.

Theoretical analysis of SAW propagation characteristics in (100) oriented AlN/diamond structure.

PubMed

Ro, Ruyen; Chiang, Yuan-Feng; Sung, Chia-Chi; Lee, Ruyue; Wu, Sean

2010-01-01

In this study, the finite element method is employed to calculate SAW characteristics in (100) AlN/diamond based structures with different electrical interfaces; i.e., IDT/ AlN/diamond, AlN/IDT/diamond, IDT/AlN/thin metal film/ diamond, and thin metal film/AlN/IDT/diamond. The effects of Cu and Al electrodes as well as the thickness of electrode on phase velocity, coupling coefficient, and reflectivity of SAWs are illustrated. Propagation characteristics of SAWs in (002) AlN/diamond-based structures are also presented for comparison. Simulation results show that to retain a large reflectivity for the design of RF filters and duplexers, the Cu IDT/(100) AlN/diamond structure possesses the highest phase velocity and largest coupling coefficient at the smallest AlN film thickness- to-wavelength ratio.

Hydrogen-terminated diamond vertical-type metal oxide semiconductor field-effect transistors with a trench gate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inaba, Masafumi, E-mail: inaba-ma@ruri.waseda.jp; Muta, Tsubasa; Kobayashi, Mikinori

2016-07-18

The hydrogen-terminated diamond surface (C-H diamond) has a two-dimensional hole gas (2DHG) layer independent of the crystal orientation. A 2DHG layer is ubiquitously formed on the C-H diamond surface covered by atomic-layer-deposited-Al{sub 2}O{sub 3}. Using Al{sub 2}O{sub 3} as a gate oxide, C-H diamond metal oxide semiconductor field-effect transistors (MOSFETs) operate in a trench gate structure where the diamond side-wall acts as a channel. MOSFETs with a side-wall channel exhibit equivalent performance to the lateral C-H diamond MOSFET without a side-wall channel. Here, a vertical-type MOSFET with a drain on the bottom is demonstrated in diamond with channel current modulationmore » by the gate and pinch off.« less

Grain-size-dependent diamond-nondiamond composite films: characterization and field-emission properties.

PubMed

Pradhan, Debabrata; Lin, I Nan

2009-07-01

Diamond films with grain sizes in the range of 5-1000 nm and grain boundaries containing nondiamond carbon are deposited on a silicon substrate by varying the deposition parameters. The overall morphologies of the as-deposited diamond-nondiamond composite films are examined by scanning electron microscopy and atomic force microscopy, which show a decrease in the surface roughness with a decrease in the diamond grain size. Although the Raman spectra show predominately nondiamond carbon features in the diamond films with smaller grain sizes, glancing-angle X-ray diffraction spectra show the absence of graphitic carbon features and the presence of very small amorphous carbon diffraction features. The CH4 percentage (%) in Ar and H2 plasma during deposition plays a crucial role in the formation of diamond films with different grain sizes and nondiamond carbon contents, which, in turn, determines the field-emission behavior of the corresponding diamond films. The smaller the grain size of the diamond, the lower is the turn-on field for electron emission. A lower turn-on field is obtained from the diamond films deposited with 2-5% CH4 than from the films deposited with either 1% or 7.5% CH4 in the Ar medium. A current density greater than 1 mA/cm2 (at 50 V/microm) is obtained from diamond films deposited with a higher percentage of CH4. A model is suggested for the field-emission mechanism from the diamond-nondiamond composite films with different diamond grain sizes and nondiamond contents.

Effect of PDC bit design and confining pressure on bit-balling tendencies while drilling shale using water base mud

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hariharan, P.R.; Azar, J.J.

1996-09-01

A good majority of all oilwell drilling occurs in shale and other clay-bearing rocks. In the light of relatively fewer studies conducted, the problem of bit-balling in PDC bits while drilling shale has been addressed with the primary intention of attempting to quantify the degree of balling, as well as to investigate the influence of bit design and confining pressures. A series of full-scale laboratory drilling tests under simulated down hole conditions were conducted utilizing seven different PDC bits in Catoosa shale. Test results have indicated that the non-dimensional parameter R{sub d} [(bit torque).(weight-on-bit)/(bit diameter)] is a good indicator ofmore » the degree of bit-balling and that it correlated well with Specific-Energy. Furthermore, test results have shown bit-profile and bit-hydraulic design to be key parameters of bit design that dictate the tendency of balling in shales under a given set of operating conditions. A bladed bit was noticed to ball less compared to a ribbed or open-faced bit. Likewise, related to bit profile, test results have indicated that the parabolic profile has a lesser tendency to ball compared to round and flat profiles. The tendency of PDC bits to ball was noticed to increase with increasing confining pressures for the set of drilling conditions used.« less

3-D X-ray tomography of diamondiferous mantle eclogite xenoliths, Siberia: A review

NASA Astrophysics Data System (ADS)

Howarth, Geoffrey H.; Sobolev, Nikolay V.; Pernet-Fisher, John F.; Ketcham, Richard A.; Maisano, Jessica A.; Pokhilenko, Lyudmila N.; Taylor, Dawn; Taylor, Lawrence A.

2015-04-01

Diamonds form over billions of years, hundreds of kilometers beneath the Earth's surface, and in combination with inclusions trapped within, provide important constraints on the evolution of the mantle over geological time. Diamonds are generally studied as individual crystals sourced from highly explosive kimberlite pipes, which entrain and subsequently disaggregate mantle fragments (xenoliths) en route to the surface. This has resulted in a general absence of robust textural descriptions of diamonds relative to their hosting mantle protolith. The textural associations of diamonds within their mantle host rocks are reviewed here on the basis of a compilation of X-ray tomographic data for 17 diamondiferous eclogite xenoliths from Siberian kimberlites. This review represents a comprehensive description of diamonds relative to their host silicates. The lack of such descriptions in previous studies is largely due to the rarity of these xenoliths, the difficulty in preparing petrographic thin sections containing diamonds, and their high-monetary value. High-resolution computed X-ray tomography (HRCXT) produces up to 1200 sequential 2-D slices through individual xenoliths, each of which represents a 'pseudo thin-section' with a resolution on the order of 5-20 μm. The improved resolution of X-ray imaging in recent studies allows for the identification of not only primary minerals, but metasomatic minerals assemblages, including: 'spongy' textured clinopyroxene, phlogopite/K-richterite, and hercynitic spinel, allowing for the delineation of distinct metasomatic pathways through the xenoliths and their relationship to diamonds. Diamonds are observed in three distinct textural settings, potentially representing several temporally distinct diamond growth events, these setting includes: (1) diamonds completely enclosed in garnet; (2) diamonds associated with highly embayed silicate grain boundaries; and (3) diamonds contained within distinct metasomatic 'plumbing-systems'. Diamonds observed completely enclosed in garnets suggest an early diamond-forming event prior to major re-crystallization and eclogite formation during subduction. The occurrence of diamond in association with embayed garnets suggests that diamond grew at the expense of the hosting silicate protolith. In addition, the spatial relationships of diamonds with metasomatic pathways, which are generally interpreted to result from late-stage proto-kimberlitic fluid percolation, indicate a period of diamond growth occurring close to, but prior to, the time of kimberlite emplacement. Furthermore, the paragenesis of sulfides within eclogite xenoliths are described using 3-D models for entire xenoliths volumes, providing important constraints of the timing of sulfide mobilization within the mantle. Three-D animations created using X-ray tomography data for ten of the xenoliths can be viewed at the following link: http://eps.utk.edu/faculty/taylor/tomography.php

Diamond growth from oxidized carbon sources beneath the Northern Slave Craton, Canada: A δ 13C-N study of eclogite-hosted diamonds from the Jericho kimberlite

NASA Astrophysics Data System (ADS)

Smart, Katie A.; Chacko, Thomas; Stachel, Thomas; Muehlenbachs, Karlis; Stern, Richard A.; Heaman, Larry M.

2011-10-01

Diamonds from high- and low-MgO groups of eclogite xenoliths from the Jericho kimberlite, Slave Craton, Canada were analyzed for carbon isotope compositions and nitrogen contents. Diamonds extracted from the two groups show remarkably different nitrogen abundances and δ 13C values. While diamonds from high-MgO eclogites have low nitrogen contents (5-82 ppm) and extremely low δ 13C values clustering at ˜-40‰, diamonds from the low-MgO eclogites have high nitrogen contents (>1200 ppm) and δ 13C values from -3.5‰ to -5.3‰. Coupled cathodoluminescence (CL) imaging and SIMS analysis of the Jericho diamonds provides insight into diamond growth processes. Diamonds from the high-MgO eclogites display little CL structure and generally have constant δ 13C values and nitrogen contents. Some of these diamonds have secondary rims with increasing δ 13C values from -40‰ to ˜-34‰, which suggests secondary diamond growth occurred from an oxidized growth medium. The extreme negative δ 13C values of the high-MgO eclogite diamonds cannot be produced by Rayleigh isotopic fractionation of average mantle-derived carbon (-5‰) or carbon derived from typical organic matter (˜-25‰). However, excursions in δ 13C values to -60‰ are known in the organic sedimentary record at ca. 2.7 and 2.0 Ga, such that diamonds from the high-MgO eclogites could have formed from similar organic matter brought into the Slave lithospheric mantle by subduction. SIMS analyses of a diamond from a low-MgO eclogite show an outer core with systematic rimwards increases in δ 13C values coupled with decreases in nitrogen contents, and a rim with pronounced alternating growth zones. The coupled δ 13C-nitrogen data suggest that the diamond precipitated during fractional crystallization from an oxidized fluid/melt from which nitrogen was progressively depleted during growth. Model calculations of the co-variation of δ 13C-N yielded a partition coefficient ( KN) value of 5, indicating that nitrogen is strongly compatible in diamond relative to the growth medium. δ 13C values of diamond cores (-4‰) dictate the growth medium had higher δ 13C values than primary mantle-derived carbon. Therefore, possible carbon sources for the low-MgO eclogite diamonds include oxidized mantle-derived (e.g. protokimberlite or carbonatite) fluids/melts that underwent some fractionation during migration or, devolatilized subducted carbonates.

Near-ultraviolet micro-Raman study of diamond grown on GaN

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nazari, M., E-mail: m-n79@txstate.edu; Hancock, B. L.; Anderson, J.

2016-01-18

Ultraviolet (UV) micro-Raman measurements are reported of diamond grown on GaN using chemical vapor deposition. UV excitation permits simultaneous investigation of the diamond (D) and disordered carbon (DC) comprising the polycrystalline layer. From line scans of a cross-section along the diamond growth direction, the DC component of the diamond layer is found to be highest near the GaN-on-diamond interface and diminish with characteristic length scale of ∼3.5 μm. Transmission electron microscopy (TEM) of the diamond near the interface confirms the presence of DC. Combined micro-Raman and TEM are used to develop an optical method for estimating the DC volume fraction.

Study on effect of plasma surface treatments for diamond deposition by DC arc plasmatron.

PubMed

Kang, In-Je; Joa, Sang-Beom; Lee, Heon-Ju

2013-11-01

To improve the thermal conductivity and wear resistance of ceramic materials in the field of renewable energy technologies, diamond coating by plasma processing has been carried out in recent years. This study's goal is to improve diamond deposition on Al2O3 ceramic substrates by plasma surface treatments. Before diamond deposition was carried out in a vacuum, plasma surface treatments using Ar gas were conducted to improve conditions for deposition. We also conducted plasma processing for diamond deposition on Al2O3 ceramic substrates using a DC arc Plasmatron. The Al2O3 ceramic substrates with diamond film (5 x 15 mm2), were investigated by SEM (Scanning Electron Microscopy), AFM (Atomic Force Microscopy) and XRD (X-ray Diffractometer). Then, the C-H stretching of synthetic diamond films by FTIR (Fourier Transform Infrared Spectroscopy) was studied. We identified nanocrystalline diamond films on the Al2O3 ceramic substrates. The results showed us that the deposition rate of diamond films was 2.3 microm/h after plasma surface treatments. Comparing the above result with untreated ceramic substrates, the deposition rate improved with the surface roughness of the deposited diamond films.

Diamond Smoothing Tools

NASA Technical Reports Server (NTRS)

Voronov, Oleg

2007-01-01

Diamond smoothing tools have been proposed for use in conjunction with diamond cutting tools that are used in many finish-machining operations. Diamond machining (including finishing) is often used, for example, in fabrication of precise metal mirrors. A diamond smoothing tool according to the proposal would have a smooth spherical surface. For a given finish machining operation, the smoothing tool would be mounted next to the cutting tool. The smoothing tool would slide on the machined surface left behind by the cutting tool, plastically deforming the surface material and thereby reducing the roughness of the surface, closing microcracks and otherwise generally reducing or eliminating microscopic surface and subsurface defects, and increasing the microhardness of the surface layer. It has been estimated that if smoothing tools of this type were used in conjunction with cutting tools on sufficiently precise lathes, it would be possible to reduce the roughness of machined surfaces to as little as 3 nm. A tool according to the proposal would consist of a smoothing insert in a metal holder. The smoothing insert would be made from a diamond/metal functionally graded composite rod preform, which, in turn, would be made by sintering together a bulk single-crystal or polycrystalline diamond, a diamond powder, and a metallic alloy at high pressure. To form the spherical smoothing tip, the diamond end of the preform would be subjected to flat grinding, conical grinding, spherical grinding using diamond wheels, and finally spherical polishing and/or buffing using diamond powders. If the diamond were a single crystal, then it would be crystallographically oriented, relative to the machining motion, to minimize its wear and maximize its hardness. Spherically polished diamonds could also be useful for purposes other than smoothing in finish machining: They would likely also be suitable for use as heat-resistant, wear-resistant, unlubricated sliding-fit bearing inserts.

Comparison of cutting efficiency with different diamond burs and water flow rates in cutting lithium disilicate glass ceramic.

PubMed

Siegel, Sharon C; Patel, Tejas

2016-10-01

This study compared different diamond burs and different water flow rates on the cutting efficiency of sectioning through lithium disilicate glass ceramic. The authors used a standardized cutting regimen with 4 brands of diamond burs to section through lithium disilicate glass ceramic blocks. Twelve diamonds of each brand cut through the blocks in randomized order. In the first part of the study, the authors recorded sectioning rates in millimeters per minute for each diamond bur as a measure of cutting efficiency. In the second part of the study, the authors compared sectioning rates using only 1 brand of diamond bur, with 3 different water flow rates. The authors averaged and compared cutting rates of each brand of diamond bur and the cutting rates for each flow rate using an analysis of variance and determined the differences with a Tukey honest significant difference test. One diamond bur cut significantly slower than the other 3, and one diamond bur cut significantly faster than 2 of the others. The diamond bur cutting efficiency through lithium disilicate glass ceramic with a 20 mL/min water flow rate was significantly higher than 15 mL/min. There are differences in cutting efficiency between diamond burs when sectioning lithium disilicate glass ceramic. Use a minimum of 20 mL/min of water coolant flow when sectioning lithium disilicate glass ceramic with dental diamond burs to maximize cutting efficiency. Recommendations for specific diamond burs with a coarse grit and water flow rate of 20 mL/min can be made when removing or adjusting restorations made from lithium disilicate glass ceramic. Copyright © 2016 American Dental Association. Published by Elsevier Inc. All rights reserved.

Industrial diamond

USGS Publications Warehouse

Olson, D.W.

2011-01-01

Estimated world production of natural and synthetic industrial diamond was about 4.44 billion carats in 2010. Natural industrial diamond deposits have been found in more than 35 countries, and synthetic industrial diamond is produced in at least 15 countries.

Diamond formation through isochemical cooling of CHO fluids vs redox buffering: examples from Marange peridotitic and Zimmi eclogitic diamonds

NASA Astrophysics Data System (ADS)

Smit, Karen V.; Stachel, Thomas; Stern, Richard A.; Shirey, Steven B.; Steele, Andrew

2017-04-01

Traditional models for diamond formation within the lithospheric mantle invoke either carbonate reduction or methane oxidation. Both these mechanisms require some oxygen exchange with the surrounding wall-rock at the site of diamond precipitation. However, peridotite does not have sufficient buffering capacity to allow for diamond formation via these traditional models and instead peridotitic diamonds may form through isochemical cooling of H2O-rich CHO fluids [1]. Marange mixed-habit diamonds from eastern Zimbabwe provide the first natural confirmation of this new diamond growth model [2]. Although Marange diamonds do not contain any silicate or sulphide inclusions, they contain Ni-N-vacancy complexes detected through photoluminescence (PL) spectroscopy that suggest the source fluids equilibrated in the Ni-rich depleted peridotitic lithosphere. Cuboid sectors also contain abundant micro-inclusions of CH4, the first direct observation of reduced CH4-rich fluids that are thought to percolate through the lithospheric mantle [2]. In fluid inclusion-free diamonds, core-to-rim trends in δ13C and N content are used to infer the speciation of the diamond-forming fluid. Core to rim trends of increasing δ13C with decreasing N content are interpreted as diamond growth from oxidized CO2- or carbonate-bearing fluids. Diamond growth from reduced species should show the opposite trends - decreasing δ13C from core to rim with decreasing N content. Within the CH4-bearing growth sectors of Marange diamonds, however, such a 'reduced' trend is not observed. Rather, δ13C increases from core to rim within a homogeneously grown zone [2]. These contradictory observations can be explained through either mixing between CH4- and CO2-rich end-members of hydrous fluids [2] or through closed system precipitation from an already mixed CH4-CO2 H2O-maximum fluid with XCO2 (CO2/[CO2+CH4]) between 0.3 and 0.7 [3]. These results demonstrate that Marange diamonds precipitated from cooling CH4-CO2-bearing hydrous fluids rather than through redox buffering. As this growth mechanism applies to both the fluid-rich cuboid and gem-like octahedral sectors of Marange diamonds, a non-redox model for diamond formation from mixed CH4-CO2 fluids is indicated for a wider range of gem-quality peridotitic diamonds. Indeed, at the redox conditions of global diamond-bearing lithospheric mantle (FMQ -2 to -4; [4]), CHO fluids are strongly water-dominated and contain both CH4 and CO2 as dominant carbon species [5]. By contrast diamond formation in eclogitic assemblages, through either redox buffering or cooling of carbon-bearing fluids, is not as well constrained. Zimmi diamonds from the West African craton have eclogitic sulphide inclusions (with low Ni and high Re/Os) and formed at 650 Ma, overlapping with the timing of subduction [6]. In one Zimmi diamond, a core to rim trend of decreasing δ13C (-23.4 to -24.5 ) and N content is indicative of formation from reduced C2H6/CH4-rich fluids, likely derived from oceanic crust recycled during Neoproterozoic subduction. Unlike mixed CH4-CO2 fluids near the water maximum, isochemical cooling or ascent of such reduced CHO fluids is not effficient at diamond precipitation. Furthermore, measurable carbon isotopic variations in diamond are not predicted in this model and therefore cannot be reconciled with the ˜1 ‰ internal variation seen. Consequently, this Zimmi eclogitic diamond likely formed through redox buffering of reduced subduction-related fluids, infiltrating into sulphide-bearing eclogite. References 1. Luth and Stachel, 2014. CMP, 168, 1083 2. Smit et al., 2016. Lithos, 265, 68-81 3. Stachel et al., in review 4. Stagno et al., 2013. Nature, 493, 84-88 5. Zhang and Duan, 2009. GCA 73, 2089-2102 6. Smit et al., 2016. Precamb Res, 286, 152-166

Note: Novel diamond anvil cell for electrical measurements using boron-doped metallic diamond electrodes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Matsumoto, R.; Sasama, Y.; Yamaguchi, T.

2016-07-15

A novel diamond anvil cell suitable for electrical transport measurements under high pressure has been developed. A boron-doped metallic diamond film was deposited as an electrode on a nano-polycrystalline diamond anvil using a microwave plasma-assisted chemical vapor deposition technique combined with electron beam lithography. The maximum pressure that can be achieved by this assembly is above 30 GPa. We report electrical transport measurements of Pb up to 8 GPa. The boron-doped metallic diamond electrodes showed no signs of degradation after repeated compression.

Industrial diamond

USGS Publications Warehouse

Olson, D.W.

2000-01-01

Part of the 1999 Industrial Minerals Review. A review of the state of the global industrial diamond industry in 1999 is presented. World consumption of industrial diamond has increased annually in recent years, with an estimated 500 million carats valued between $650 million and $800 million consumed in 1999. In 1999, the U.S. was the world's largest market for industrial diamond and was also one of the world's main producers; the others were Ireland, Russia, and South Africa. Uses of industrial diamonds are discussed, and prices of natural and synthetic industrial diamond are reported.

Materials Research Society Symposium Proceedings on Diamond, SiC and Nitride Wide Bandgap Semiconductors Held at San Francisco, California on 4-8 April 1994. Volume 339.

DTIC Science & Technology

1994-04-08

demonstrated that there existed no graphite phase at the surface of the as-deposited and 02 plasma treated polycrystalline diamond films. W 3- uO 2.5...diamond, highly ordered pyrolitic graphite ( HOPG ), and an amorphous carbon surface created by 1 keV ion bombardment of diamond. The diamond surface was...Library of Congress Cataloging in Publication Data Materials Research Society. Meeting (1994 : San Francisco, Calif.). Symposium D. Diamond, SiC and nitride

Fluidized bed deposition of diamond

DOEpatents

Laia, Jr., Joseph R.; Carroll, David W.; Trkula, Mitchell; Anderson, Wallace E.; Valone, Steven M.

1998-01-01

A process for coating a substrate with diamond or diamond-like material including maintaining a substrate within a bed of particles capable of being fluidized, the particles having substantially uniform dimensions and the substrate characterized as having different dimensions than the bed particles, fluidizing the bed of particles, and depositing a coating of diamond or diamond-like material upon the substrate by chemical vapor deposition of a carbon-containing precursor gas mixture, the precursor gas mixture introduced into the fluidized bed under conditions resulting in excitation mechanisms sufficient to form the diamond coating.

Diamond heteroepitaxial lateral overgrowth

DOE PAGES

Tang, Y. -H.; Bi, B.; Golding, B.

2015-02-24

A method of diamond heteroepitaxial lateral overgrowth is demonstrated which utilizes a photolithographic metal mask to pattern a thin (001) epitaxial diamond surface. Significant structural improvement was found, with a threading dislocation density reduced by two orders of magnitude at the top surface of a thick overgrown diamond layer. In the initial stage of overgrowth, a reduction of diamond Raman linewidth in the overgrown area was also realized. Thermally-induced stress and internal stress were determined by Raman spectroscopy of adhering and delaminated diamond films. As a result, the internal stress is found to decrease as sample thickness increases.

Recent results on CVD diamond radiation sensors

NASA Astrophysics Data System (ADS)

Weilhammer, P.; Adam, W.; Bauer, C.; Berdermann, E.; Bogani, F.; Borchi, E.; Bruzzi, M.; Colledani, C.; Conway, J.; Dabrowski, W.; Delpierre, P.; Deneuville, A.; Dulinski, W.; v. d. Eijk, R.; van Eijk, B.; Fallou, A.; Fish, D.; Fried, M.; Gan, K. K.; Gheeraert, E.; Grigoriev, E.; Hallewell, G.; Hall-Wilton, R.; Han, S.; Hartjes, F.; Hrubec, J.; Husson, D.; Kagan, H.; Kania, D.; Kaplon, J.; Kass, R.; Knopfle, K. T.; Krammer, M.; Manfredi, P. F.; Meier, D.; LeNormand; Pan, L. S.; Pernegger, H.; Pernicka, M.; Plano, R.; Re, V.; Riester, J. L.; Roe, S.; Roff; Rudge, A.; Schieber, M.; Schnetzer, S.; Sciortino, S.; Speziali, V.; Stelzer, H.; Stone, R.; Tapper, R. J.; Tesarek, R.; Thomson, G. B.; Trawick, M.; Trischuk, W.; Turchetta, R.; RD 42 Collaboration

1998-02-01

CVD diamond radiation sensors are being developed for possible use in trackers in the LHC experiments. The diamond promises to be radiation hard well beyond particle fluences that can be tolerated by Si sensors. Recent results from the RD 42 collaboration on charge collection distance and on radiation hardness of CVD diamond samples will be reported. Measurements with diamond tracking devices, both strip detectors and pixel detectors, will be discussed. Results from beam tests using a diamond strip detector which was read out with fast, 25 ns shaping time, radiation-hard pipeline electronics will be presented.

Auto-Gopher: A Wire-Line Rotary-Hammer Ultrasonic Drill

NASA Technical Reports Server (NTRS)

Badescu, Mircea; Sherrit, Stewart; Bao, Xiaogi; Bar-Cohen, Yoseph; Chen, Beck

2011-01-01

Developing technologies that would enable NASA to sample rock, soil, and ice by coring, drilling or abrading at a significant depth is of great importance for a large number of in-situ exploration missions as well as for earth applications. Proven techniques to sample Mars subsurface will be critical for future NASA astrobiology missions that will search for records of past and present life on the planet, as well as, the search for water and other resources. A deep corer, called Auto-Gopher, is currently being developed as a joint effort of the JPL's NDEAA laboratory and Honeybee Robotics Corp. The Auto-Gopher is a wire-line rotary-hammer drill that combines rock breaking by hammering using an ultrasonic actuator and cuttings removal by rotating a fluted bit. The hammering mechanism is based on the Ultrasonic/Sonic Drill/Corer (USDC) that has been developed as an adaptable tool for many of drilling and coring applications. The USDC uses an intermediate free-flying mass to transform the high frequency vibrations of the horn tip into a sonic hammering of a drill bit. The USDC concept was used in a previous task to develop an Ultrasonic/Sonic Ice Gopher. The lessons learned from testing the ice gopher were implemented into the design of the Auto-Gopher by inducing a rotary motion onto the fluted coring bit. A wire-line version of such a system would allow penetration of significant depth without a large increase in mass. A laboratory version of the corer was developed in the NDEAA lab to determine the design and drive parameters of the integrated system. The design configuration lab version of the design and fabrication and preliminary testing results are presented in this paper

In situ analysis of carbon isotopes in North American diamonds

NASA Astrophysics Data System (ADS)

van Rythoven, A. D.; Hauri, E. H.; Wang, J.; McCandless, T.; Shirey, S. B.; Schulze, D. J.

2010-12-01

Diamonds from three North American kimberlite occurrences were investigated with cathodoluminescence (CL) and secondary ion mass spectrometry (SIMS) to determine their growth history and carbon isotope composition. Diamonds analyzed include fourteen from Lynx (Quebec), twelve from Kelsey Lake (Colorado) and eleven from A154 South (Diavik mine, Northwest Territories). Growth histories for the diamonds vary from simple to highly complex based on their CL images and depending on the individual stone. Deformation laminae are evident in CL images of the Lynx diamonds that typically are brownish in color. Two to five points per diamond were analyzed by SIMS for carbon isotope composition. Sample heterogeneity is minimal in terms of δ13C (vs. PDB) values. Points within single diamond had a maximum range of approximately 1 ‰. The results for the A154 South (-6.4 to -3 ‰) and Kelsey Lake (-11.2 to -2.6 ‰) stones were in accordance with earlier reported values. The Lynx kimberlite stones have anomalously high ratios and range from -3.5 to +0.2 ‰ (average: -1.4 ‰). No previous carbon isotope analyses on diamonds from Lynx or any other eastern Superior craton occurrence have been published. The diamonds possess carbon isotope ratios higher than those for the only other reported analyses of Superior craton diamonds at Wawa, Ontario (-5.5 to -1.1 ‰). In global terms, the only published analyses of diamonds that consistently contain even higher values are those from New South Wales (Australia). However, these diamonds are alluvial and contain eclogitic and/or exotic mineral inclusions. The Lynx diamonds are entirely peridotitic and from a primary deposit. The unusually low (i.e. >-5‰) δ13C values of the Lynx (and Wawa) diamonds may indicate a different carbon reservoir for the Superior craton mantle as compared to other cratons.

Quantitative analysis of trace element concentrations in some gem-quality diamonds

NASA Astrophysics Data System (ADS)

McNeill, J.; Pearson, D. G.; Klein-Ben David, O.; Nowell, G. M.; Ottley, C. J.; Chinn, I.

2009-09-01

The geochemical signature of diamond-forming fluids can be used to unravel diamond-forming processes and is of potential use in the detection of so-called 'conflict' diamonds. While fluid-rich fibrous diamonds can be analyzed by a variety of techniques, very few data have been published for fluid-poor, gem-quality diamonds because of their very low impurity levels. Here we present a new ICPMS-based (ICPMS: inductively coupled plasma mass spectrometry) method for the analysis of trace element concentrations within fluid-poor, gem-quality diamonds. The method employs a closed-system laser ablation cell. Diamonds are ablated and the products trapped for later pre-concentration into solutions that are analyzed by sector-field ICPMS. We show that our limits of quantification for a wide range of elements are at the sub-pg to low pg level. The method is applied to a suite of 10 diamonds from the Cullinan Mine (previously known as Premier), South Africa, along with other diamonds from Siberia (Mir and Udachnaya) and Venezuela. The concentrations of a wide range of elements for all the samples (expressed by weight in the solid) are very low, with rare earth elements along with Y, Nb, Cs ranging from 0.01 to 2 ppb. Large ion lithophile elements (LILE) such as Rb and Ba vary from 1 to 30 ppb. Ti ranges from ppb levels up to 2 ppm. From the combined, currently small data set we observe two kinds of diamond-forming fluids within gem diamonds. One group has enrichments in LILE over Nb, whereas a second group has normalized LILE abundances more similar to those of Nb. These two groups bear some similarity to different groups of fluid-rich diamonds, providing some supporting evidence of a link between the parental fluids for both fluid-inclusion-rich and gem diamonds.

Boron-doped diamond electrode: synthesis, characterization, functionalization and analytical applications.

PubMed

Luong, John H T; Male, Keith B; Glennon, Jeremy D

2009-10-01

In recent years, conductive diamond electrodes for electrochemical applications have been a major focus of research and development. The impetus behind such endeavors could be attributed to their wide potential window, low background current, chemical inertness, and mechanical durability. Several analytes can be oxidized by conducting diamond compared to other carbon-based materials before the breakdown of water in aqueous electrolytes. This is important for detecting and/or identifying species in solution since oxygen and hydrogen evolution do not interfere with the analysis. Thus, conductive diamond electrodes take electrochemical detection into new areas and extend their usefulness to analytes which are not feasible with conventional electrode materials. Different types of diamond electrodes, polycrystalline, microcrystalline, nanocrystalline and ultrananocrystalline, have been synthesized and characterized. Of particular interest is the synthesis of boron-doped diamond (BDD) films by chemical vapor deposition on various substrates. In the tetrahedral diamond lattice, each carbon atom is covalently bonded to its neighbors forming an extremely robust crystalline structure. Some carbon atoms in the lattice are substituted with boron to provide electrical conductivity. Modification strategies of doped diamond electrodes with metallic nanoparticles and/or electropolymerized films are of importance to impart novel characteristics or to improve the performance of diamond electrodes. Biofunctionalization of diamond films is also feasible to foster several useful bioanalytical applications. A plethora of opportunities for nanoscale analytical devices based on conducting diamond is anticipated in the very near future.

Development of Designer Diamond Anvils for High Pressure-High-Temperature Experiments in Support of the Stockpile Stewardship Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yogesh K. Vohra

The focus of this program at the University of Alabama at Birmingham (UAB) is to develop the next generation of designer diamond anvils that can perform simultaneous joule heating and temperature profile measurements in a diamond anvil cell. A series of tungsten-rhenium thermocouples will be fabricated onto to the anvil and encapsulated by a chemical vapor deposited diamond layer to allow for a complete temperature profile measurement across the anvil. The tip of the diamond anvil will be engineered to reduce the thermal conductivity so that the tungsten-heating coils can be deposited on top of this layer. Several different approachesmore » will be investigated to engineer the tip of the diamond anvil for reduction in thermal conductivity (a) isotopic mixture of 12C and 13C in the diamond layer, (b) doping of diamond with impurities (nitrogen and/or boron), and (c) growing diamond in a higher concentration of methane in hydrogen plasma. Under this academic alliance with Lawrence Livermore National Laboratory (LLNL), PI and his graduate students will use the lithographic and diamond polishing facility at LLNL. This proposed next generation of designer diamond anvils will allow multi-tasking capability with the ability to measure electrical, magnetic, structural and thermal data on actinide materials with unparallel sensitivity in support of the stockpile stewardship program.« less

Inhibiting the oxidation of diamond during preparing the vitrified dental grinding tools by depositing a ZnO coating using direct urea precipitation method.

PubMed

Wang, Yanhui; Yuan, Yungang; Cheng, Xiaozhe; Li, Xiaohu; Zang, Jianbing; Lu, Jing; Yu, Yiqing; Xu, Xipeng

2015-08-01

Oxidation of diamond during the manufacturing of vitrified dental grinding tools would reduce the strength and sharpness of tools. Zinc oxide (ZnO) coating was deposited on diamond particles by urea precipitation method to protect diamond in borosilicate glass. The FESEM results showed that the ZnO coating was formed by plate-shaped particles. According to the TG results, the onset oxidation temperature of the ZnO-coated diamond was about 70 °C higher than the pristine diamond. The EDS results showed that ZnO diffused into the borosilicate glass during sintering. As the result, the bending strength of the composites containing ZnO-coated diamond was increased by 24% compared to that of the composites containing pristine diamond. Copyright © 2015 Elsevier B.V. All rights reserved.

Thermally stable diamond brazing

DOEpatents

Radtke, Robert P [Kingwood, TX

2009-02-10

A cutting element and a method for forming a cutting element is described and shown. The cutting element includes a substrate, a TSP diamond layer, a metal interlayer between the substrate and the diamond layer, and a braze joint securing the diamond layer to the substrate. The thickness of the metal interlayer is determined according to a formula. The formula takes into account the thickness and modulus of elasticity of the metal interlayer and the thickness of the TSP diamond. This prevents the use of a too thin or too thick metal interlayer. A metal interlayer that is too thin is not capable of absorbing enough energy to prevent the TSP diamond from fracturing. A metal interlayer that is too thick may allow the TSP diamond to fracture by reason of bending stress. A coating may be provided between the TSP diamond layer and the metal interlayer. This coating serves as a thermal barrier and to control residual thermal stress.

Single crystal diamond membranes for nanoelectronics.

PubMed

Bray, Kerem; Kato, Hiromitsu; Previdi, Rodolfo; Sandstrom, Russell; Ganesan, Kumaravelu; Ogura, Masahiko; Makino, Toshiharu; Yamasaki, Satoshi; Magyar, Andrew P; Toth, Milos; Aharonovich, Igor

2018-02-22

Single crystal, nanoscale diamond membranes are highly sought after for a variety of applications including nanophotonics, nanoelectronics and quantum information science. However, so far, the availability of conductive diamond membranes has remained an unreachable goal. In this work we present a complete nanofabrication methodology for engineering high aspect ratio, electrically active single crystal diamond membranes. The membranes have large lateral directions, exceeding ∼500 × 500 μm 2 and are only several hundreds of nanometers thick. We further realize vertical single crystal p-n junctions made from the diamond membranes that exhibit onset voltages of ∼10 V and a current of several mA. Moreover, we deterministically introduce optically active color centers into the membranes, and demonstrate for the first time a single crystal nanoscale diamond LED. The robust and scalable approach to engineer the electrically active single crystal diamond membranes offers new pathways for advanced nanophotonic, nanoelectronic and optomechanical devices employing diamond.

Carbon isotope fractionation during diamond growth in depleted peridotite: Counterintuitive insights from modelling water-maximum CHO fluids as multi-component systems

NASA Astrophysics Data System (ADS)

Stachel, T.; Chacko, T.; Luth, R. W.

2017-09-01

Because of the inability of depleted cratonic peridotites to effectively buffer oxygen fugacities when infiltrated by CHO or carbonatitic fluids, it has been proposed recently (Luth and Stachel, 2014) that diamond formation in peridotites typically does not occur by rock-buffered redox reactions as previously thought but by an oxygen-conserving reaction in which minor coexisting CH4 and CO2 components in a water-rich fluid react to form diamond (CO2 + CH4 = 2C + 2H2O). In such fluid-buffered systems, carbon isotope fractionation during diamond precipitation occurs in the presence of two dominant fluid carbon species. Carbon isotope modelling of diamond precipitation from mixed CH4- and CO2-bearing fluids reveals unexpected fundamental differences relative to diamond crystallization from a single carbon fluid species: (1) irrespective of which carbon fluid species (CH4 or CO2) is dominant in the initial fluid, diamond formation is invariably associated with progressive minor (<1‰) enrichment of diamond in 13C as crystallization proceeds. This is in contrast to diamond precipitation by rock-buffered redox processes from a fluid containing only a single carbon species, which can result in either progressive 13C enrichment (CO2 or carbonate fluids) or 13C depletion (CH4 fluids) in the diamond. (2) Fluid speciation is the key factor controlling diamond δ13 C values; as XCO2 (XCO2 = CO2/[CO2 + CH4]) in the initial fluid increases from 0.1 to 0.9 (corresponding to an increase in fO2 of 0.8 log units), the carbon isotope composition of the first-precipitated diamond decreases by 3.7‰. The tight mode in δ13C of - 5 ± 1 ‰ for diamonds worldwide places strict constraints on the dominant range of XCO2 in water-rich fluids responsible for diamond formation. Specifically, precipitation of diamonds with δ13C values in the range -4 to -6‰ from mantle-derived fluids with an average δ13C value of -5‰ (derived from evidence not related to diamonds) requires that diamond-forming fluids were relatively reduced and had methane as the dominant carbon species (XCO2 = 0.1-0.5). Application of our model to a recently published set of in-situ carbon isotope analyses for peridotitic diamonds from Marange, Zimbabwe (Smit et al., 2016), which contain CH4 fluid inclusions, allows us to perfectly match the observed co-variations in δ13 C, δ15 N and N content and at the same time explain the previously counter-intuitive observation of progressive 13C enrichment in diamonds that appear to have grown from a fluid with methane as the dominant carbon species. Similarly, the almost complete absence in the published record of progressive 13C depletion trends within diamonds likely reflects ubiquitous precipitation from CH4- and CO2-bearing water-rich fluids, rather than diamond formation exclusively by carbonate-bearing and CH4-free oxidized fluids or melts.

Why diamond dimensions and electrode geometry are crucial for small photon beam dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marsolat, F.; Tromson, D.; Tranchant, N.

2015-12-21

Recent use of very small photon beams (down to 4 mm) in stereotactic radiotherapy requires new detectors to accurately determine the delivered dose. Diamond detectors have been presented in the literature as an attractive candidate for this application, due to their small detection volume and the diamond atomic number (Z = 6) which is close to water effective atomic number (Zeff ∼ 7.42). However, diamond exhibits a density 3.51 times greater than that of water and recent studies using Monte Carlo simulations have demonstrated the drawback of a high-density detector on small beam output factors. The current study focuses on geometrical parameters of diamond detector,more » namely, the diamond dimensions and the electrode geometry, in order to solve the dosimetric issues still observed in small photon beams with diamond detectors. To give better insights to these open questions, we have used both computational method and experimental analysis. This study highlighted that reducing diamond dimensions is crucial for small beam output factor measurements and to limit the influence of its high density. Furthermore, electrodes covering the whole diamond surface were essential for a dose rate independence of the diamond detector. The optimal dosimeter derived from this work presented small diamond dimensions of approximately 1 × 1 × 0.15 mm{sup 3}, with diamond-like-carbon electrodes covering the whole diamond surface. A dose rate independence of this diamond detector (better than 0.5% over a wide range of dose rates available on a stereotactic dedicated facility) was obtained due to the electrode geometry. Concerning the output factor measurements, a good agreement (better than 1.1%) was observed between this carbon material detector and two types of passive dosimeters (LiF microcubes and EBT2 radiochromic films) for all beam sizes except the smallest field of 0.6 × 0.6 cm{sup 2} with a deviation of 2.6%. This new study showed the high performance of this diamond detector in small photon beams, in comparison with various commercially available passive and active dosimeters.« less

Kankan diamonds (Guinea) III: δ13C and nitrogen characteristics of deep diamonds

NASA Astrophysics Data System (ADS)

Stachel, T.; Harris, J. W.; Aulbach, S.; Deines, P.

Diamonds from the Kankan area in Guinea formed over a large depth profile beginning within the cratonic mantle lithosphere and extending through the asthenosphere and transition zone into the lower mantle. The carbon isotopic composition, the concentration of nitrogen impurities and the nitrogen aggregation level of diamonds representing this entire depth range have been determined. Peridotitic and eclogitic diamonds of lithospheric origin from Kankan have carbon isotopic compositions (δ13C: peridotitic -5.4 to -2.2‰ eclogitic -19.7 to -0.7‰) and nitrogen characteristics (N: peridotitic 17-648 atomic ppm; eclogitic 0-1,313 atomic ppm; aggregation from IaA to IaB) which are generally typical for diamonds of these two suites worldwide. Geothermobarometry of peridotitic and eclogitic inclusion parageneses (worldwide sources) indicates that both suites formed under very similar conditions within the cratonic lithosphere, which is not consistent with a derivation of diamonds with light carbon isotopic composition from subducted organic matter within subducting oceanic slabs. Diamonds containing majorite garnet inclusions fall to the isotopically heavy side (δ13C: -3.1‰ to +0.9‰) of the worldwide diamond population. Nitrogen contents are low (0-126 atomic ppm) and one of the two nitrogen-bearing diamonds shows such a low level of nitrogen aggregation (30% B-centre) that it cannot have been exposed to ambient temperatures of the transition zone (>=1,400 °C) for more than 0.2 Ma. This suggests rapid upward transport and formation of some Kankan diamonds pene-contemporaneous to Cretaceous kimberlite activity. Similar to these diamonds from the asthenosphere and the transition zone, lower mantle diamonds show a small shift towards isotopic heavy compositions (-6.6 to -0.5‰, mode at -3.5‰). As already observed for other mines, the nitrogen contents of lower mantle diamonds were below detection (using FTIRS). The mutual shift of sublithospheric diamonds towards isotopic heavier compositions suggests a common carbon source, which may have inherited an isotopic heavy composition from a component consisting of subducted carbonates.

Kankan diamonds (Guinea) III: δ13C and nitrogen characteristics of deep diamonds

NASA Astrophysics Data System (ADS)

Stachel, T.; Harris, J. W.; Aulbach, S.; Deines, P.

2001-08-01

Diamonds from the Kankan area in Guinea formed over a large depth profile beginning within the cratonic mantle lithosphere and extending through the asthenosphere and transition zone into the lower mantle. The carbon isotopic composition, the concentration of nitrogen impurities and the nitrogen aggregation level of diamonds representing this entire depth range have been determined. Peridotitic and eclogitic diamonds of lithospheric origin from Kankan have carbon isotopic compositions (δ13C: peridotitic -5.4 to -2.2‰ eclogitic -19.7 to -0.7‰) and nitrogen characteristics (N: peridotitic 17-648 atomic ppm; eclogitic 0-1,313 atomic ppm; aggregation from IaA to IaB) which are generally typical for diamonds of these two suites worldwide. Geothermobarometry of peridotitic and eclogitic inclusion parageneses (worldwide sources) indicates that both suites formed under very similar conditions within the cratonic lithosphere, which is not consistent with a derivation of diamonds with light carbon isotopic composition from subducted organic matter within subducting oceanic slabs. Diamonds containing majorite garnet inclusions fall to the isotopically heavy side (δ13C: -3.1‰ to +0.9‰) of the worldwide diamond population. Nitrogen contents are low (0-126 atomic ppm) and one of the two nitrogen-bearing diamonds shows such a low level of nitrogen aggregation (30% B-centre) that it cannot have been exposed to ambient temperatures of the transition zone (>=1,400 °C) for more than 0.2 Ma. This suggests rapid upward transport and formation of some Kankan diamonds pene-contemporaneous to Cretaceous kimberlite activity. Similar to these diamonds from the asthenosphere and the transition zone, lower mantle diamonds show a small shift towards isotopic heavy compositions (-6.6 to -0.5‰, mode at -3.5‰). As already observed for other mines, the nitrogen contents of lower mantle diamonds were below detection (using FTIRS). The mutual shift of sublithospheric diamonds towards isotopic heavier compositions suggests a common carbon source, which may have inherited an isotopic heavy composition from a component consisting of subducted carbonates.

Study on Platinum Coating Depth in Focused Ion Beam Diamond Cutting Tool Milling and Methods for Removing Platinum Layer.

PubMed

Choi, Woong Kirl; Baek, Seung Yub

2015-09-22

In recent years, nanomachining has attracted increasing attention in advanced manufacturing science and technologies as a value-added processes to control material structures, components, devices, and nanoscale systems. To make sub-micro patterns on these products, micro/nanoscale single-crystal diamond cutting tools are essential. Popular non-contact methods for the macro/micro processing of diamond composites are pulsed laser ablation (PLA) and electric discharge machining (EDM). However, for manufacturing nanoscale diamond tools, these machining methods are not appropriate. Despite diamond's extreme physical properties, diamond can be micro/nano machined relatively easily using a focused ion beam (FIB) technique. In the FIB milling process, the surface properties of the diamond cutting tool is affected by the amorphous damage layer caused by the FIB gallium ion collision and implantation and these influence the diamond cutting tool edge sharpness and increase the processing procedures. To protect the diamond substrate, a protection layer-platinum (Pt) coating is essential in diamond FIB milling. In this study, the depth of Pt coating layer which could decrease process-induced damage during FIB fabrication is investigated, along with methods for removing the Pt coating layer on diamond tools. The optimum Pt coating depth has been confirmed, which is very important for maintaining cutting tool edge sharpness and decreasing processing procedures. The ultra-precision grinding method and etching with aqua regia method have been investigated for removing the Pt coating layer. Experimental results show that when the diamond cutting tool width is bigger than 500 nm, ultra-precision grinding method is appropriate for removing Pt coating layer on diamond tool. However, the ultra-precision grinding method is not recommended for removing the Pt coating layer when the cutting tool width is smaller than 500 nm, because the possibility that the diamond cutting tool is damaged by the grinding process will be increased. Despite the etching method requiring more procedures to remove the Pt coating layer after FIB milling, it is a feasible method for diamond tools with under 500 nm width.

Regional patterns in the paragenesis and age of inclusions in diamond, diamond composition, and the lithospheric seismic structure of Southern Africa

NASA Astrophysics Data System (ADS)

Shirey, Steven B.; Harris, Jeffrey W.; Richardson, Stephen H.; Fouch, Matthew; James, David E.; Cartigny, Pierre; Deines, Peter; Viljoen, Fanus

2003-12-01

The Archean lithospheric mantle beneath the Kaapvaal-Zimbabwe craton of Southern Africa shows ±1% variations in seismic P-wave velocity at depths within the diamond stability field (150-250 km) that correlate regionally with differences in the composition of diamonds and their syngenetic inclusions. Seismically slower mantle trends from the mantle below Swaziland to that below southeastern Botswana, roughly following the surface outcrop pattern of the Bushveld-Molopo Farms Complex. Seismically slower mantle also is evident under the southwestern side of the Zimbabwe craton below crust metamorphosed around 2 Ga. Individual eclogitic sulfide inclusions in diamonds from the Kimberley area kimberlites, Koffiefontein, Orapa, and Jwaneng have Re-Os isotopic ages that range from circa 2.9 Ga to the Proterozoic and show little correspondence with these lithospheric variations. However, silicate inclusions in diamonds and their host diamond compositions for the above kimberlites, Finsch, Jagersfontein, Roberts Victor, Premier, Venetia, and Letlhakane do show some regional relationship to the seismic velocity of the lithosphere. Mantle lithosphere with slower P-wave velocity correlates with a greater proportion of eclogitic versus peridotitic silicate inclusions in diamond, a greater incidence of younger Sm-Nd ages of silicate inclusions, a greater proportion of diamonds with lighter C isotopic composition, and a lower percentage of low-N diamonds whereas the converse is true for diamonds from higher velocity mantle. The oldest formation ages of diamonds indicate that the mantle keels which became continental nuclei were created by middle Archean (3.2-3.3 Ga) mantle depletion events with high degrees of melting and early harzburgite formation. The predominance of sulfide inclusions that are eclogitic in the 2.9 Ga age population links late Archean (2.9 Ga) subduction-accretion events involving an oceanic lithosphere component to craton stabilization. These events resulted in a widely distributed younger Archean generation of eclogitic diamonds in the lithospheric mantle. Subsequent Proterozoic tectonic and magmatic events altered the composition of the continental lithosphere and added new lherzolitic and eclogitic diamonds to the already extensive Archean diamond suite.

STS-65 Columbia, OV-102, lifts off from KSC Launch Complex (LC) Pad 39A

NASA Technical Reports Server (NTRS)

1994-01-01

Columbia, Orbiter Vehicle (OV) 102, atop its external tank (ET) rises above the Kennedy Space Center (KSC) Launch Complex (LC) Pad 39A after liftoff at 12:43 pm Eastern Daylight Time (EDT). OV-102 starboard side and one of the two solid rocket boosters (SRBs) are visible in this launch view. The retracted rotating service structure (RSS) is nearly covered in the shuttle's exhaust at the left as OV-102 clears the fixed service structure (FSS) tower. The space shuttle main engines produce a diamond shock effect. Once in orbit, STS-65's six NASA astronauts and a Japanese Payload Specialist will begin two weeks of experimentation in support of the second International Microgravity Laboratory (IML-2) mission.

On the Fabrication and Behavior of Diamond Microelectromechanical Sensors (DMEMS)

NASA Technical Reports Server (NTRS)

Holmes, K.; Davidson, J. L.; Kang, W. P.; Howell, M.

2001-01-01

CVD (chemically vapor deposited) diamond films can be processed similar to "conventional" semiconductor device fabrication and as such can be used to achieve microelectromechanical structures (MEMS) also similar to, for example, silicon technology. Very small cantilever beams, membranes, stripes, tips, etc. can be constructed in doped and undoped diamond films and offer an array of choices in diamond with its known superior properties such as elastic modulus, high temperature semiconduction, high thermal conductivity, very low coefficient of expansion and numerous other diamond parameters. This paper will review the construction and behavior of the second generation DMEMS devices comprised as an accelerometer with a diamond diaphragm for use in very high G applications and a diamond pressure sensor for very high temperature and frequency response.

Diamond nanowires: fabrication, structure, properties, and applications.

PubMed

Yu, Yuan; Wu, Liangzhuan; Zhi, Jinfang

2014-12-22

C(sp(3) )C-bonded diamond nanowires are wide band gap semiconductors that exhibit a combination of superior properties such as negative electron affinity, chemical inertness, high Young's modulus, the highest hardness, and room-temperature thermal conductivity. The creation of 1D diamond nanowires with their giant surface-to-volume ratio enhancements makes it possible to control and enhance the fundamental properties of diamond. Although theoretical comparisons with carbon nanotubes have shown that diamond nanowires are energetically and mechanically viable structures, reproducibly synthesizing the crystalline diamond nanowires has remained challenging. We present a comprehensive, up-to-date review of diamond nanowires, including a discussion of their synthesis along with their structures, properties, and applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gas-phase kinetics during diamond growth: CH4 as-growth species

NASA Astrophysics Data System (ADS)

Harris, Stephen J.

1989-04-01

We have used a one-dimensional kinetic analysis to model the gas-phase chemistry that occurred during the diamond growth experiments of Chauhan, Angus, and Gardner [J. Appl. Phys. 47, 4746 (1976)]. In those experiments the weight of diamond seed crystals heated by lamps in a CH4/H2 environment was monitored by a microbalance. No filament or electric discharge was present. Our analysis shows that diamond growth occurred in this system by direct reaction of CH4 on the diamond surface. C2H2 and CH3, which have been proposed as diamond growth species, played no significant role there, although our results do not address their possible contributions in other systems such as filament- or plasma-assisted diamond growth.

Metal films on the surfaces and within diamond crystals from Arkhangelskaya and Yakutian diamond provinces

NASA Astrophysics Data System (ADS)

Makeev, A. B.; Kriulina, G. Yu.

2012-12-01

Representative samples of diamonds from five kimberlite pipes (Lomonosovskaya, Archangel'sk, Snegurochka, XXIII Congress of the Communist Party of the Soviet Union (CPSU), and Internationalnaya) of the Arkhangelskaya and Yakutian diamond provinces in Russia have been studied. Thirty-three varieties of metal films have been identified as syngenetic associated minerals. The films consist of 15 chemical elements that occur in the form of native metals and their natural alloys. Remnants of metal films were detected within diamond crystals. The metal films coating diamonds are a worldwide phenomenon. To date, these films have been described from Europe, Asia, South America, and Africa. Native metals, their alloys, and intermetallides are actual companion minerals of diamond.

Ultrananocrystalline diamond contacts for electronic devices

DOEpatents

Sumant, Anirudha V.; Smedley, John; Muller, Erik

2016-11-01

A method of forming electrical contacts on a diamond substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The mixture of gases include a source of a p-type or an n-type dopant. The plasma ball is disposed at a first distance from the diamond substrate. The diamond substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the diamond substrate for a first time, and a UNCD film, which is doped with at least one of a p-type dopant and an n-type dopant, is disposed on the diamond substrate. The doped UNCD film is patterned to define UNCD electrical contacts on the diamond substrate.

Ultrananocrystalline diamond contacts for electronic devices

DOEpatents

Sumant, Anirudha V.; Smedley, John; Muller, Erik

2017-12-12

A method of forming electrical contacts on a diamond substrate comprises producing a plasma ball using a microwave plasma source in the presence of a mixture of gases. The mixture of gases include a source of a p-type or an n-type dopant. The plasma ball is disposed at a first distance from the diamond substrate. The diamond substrate is maintained at a first temperature. The plasma ball is maintained at the first distance from the diamond substrate for a first time, and a UNCD film, which is doped with at least one of a p-type dopant and an n-type dopant, is disposed on the diamond substrate. The doped UNCD film is patterned to define UNCD electrical contacts on the diamond substrate.

Diamond based adsorbents and their application in chromatography.

PubMed

Peristyy, Anton A; Fedyanina, Olga N; Paull, Brett; Nesterenko, Pavel N

2014-08-29

The idea of using diamond and diamond containing materials in separation sciences has attracted a strong interest in the past decade. The combination of a unique range of properties, such as chemical inertness, mechanical, thermal and hydrolytic stability, excellent thermal conductivity with minimal thermal expansion and intriguing adsorption properties makes diamond a promising material for use in various modes of chromatography. This review summarises the recent research on the preparation of diamond and diamond based stationary phases, their properties and chromatographic performance. Special attention is devoted to the dominant retention mechanisms evident for particular diamond containing phases, and their subsequent applicability to various modes of chromatography, including chromatography carried out under conditions of high temperature and pressure. Copyright © 2014 Elsevier B.V. All rights reserved.

Process for making a cesiated diamond film field emitter and field emitter formed therefrom

DOEpatents

Anderson, D.F.; Kwan, S.W.

1999-03-30

A process for making a cesiated diamond film comprises (a) depositing a quantity of cesium iodide on the diamond film in a vacuum of between about 10{sup {minus}4} Torr and about 10{sup {minus}7} Torr, (b) increasing the vacuum to at least about 10{sup {minus}8} Torr, and (c) imposing an electron beam upon the diamond film, said electron beam having an energy sufficient to dissociate said cesium iodide and to incorporate cesium into interstices of the diamond film. The cesiated diamond film prepared according to the process has an operating voltage that is reduced by a factor of at least approximately 2.5 relative to conventional, non-cesiated diamond film field emitters. 2 figs.

Process for making a cesiated diamond film field emitter and field emitter formed therefrom

DOEpatents

Anderson, David F.; Kwan, Simon W.

1999-01-01

A process for making a cesiated diamond film comprises (a) depositing a quantity of cesium iodide on the diamond film in a vacuum of between about 10.sup.-4 Torr and about 10.sup.-7 Torr, (b) increasing the vacuum to at least about 10.sup.-8 Torr, and (c) imposing an electron beam upon the diamond film, said electron beam having an energy sufficient to dissociate said cesium iodide and to incorporate cesium into interstices of the diamond film. The cesiated diamond film prepared according to the process has an operating voltage that is reduced by a factor of at least approximately 2.5 relative to conventional, non-cesiated diamond film field emitters.

Structures and Mechanical Properties of Natural and Synthetic Diamonds

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1998-01-01

A revolution in the diamond technology is in progress, as the low-pressure process becomes an industrial reality. It will soon be possible to take advantage of the demanding properties of diamond to develop a myriad of new applications, particularly for self-lubricating, wear-resistant, and superhard coatings. The production of large diamond films or sheets at low cost, a distinct possibility in the not-too-distant future, may drastically change tribology technology, particularly regarding solid lubricants and lubricating materials and systems. This paper reviews the structures and properties of natural and synthetic diamonds to gain a better understanding of the tribological properties of diamond and related materials. Atomic and crystal structure, impurities, mechanical properties, and indentation hardness of diamond are described.

Making Diamond in the Laboratory

ERIC Educational Resources Information Center

Strong, Herbert

1975-01-01

Discusses the graphite to diamond transformation and a phase diagram for carbon. Describes high temperature-higher pressure experimental apparatus and growth of diamonds from seed crystals. Reviews properties of the diamond which suggest uses for the synthetic product. Illustrations with text. (GH)

Studies of Diamonds Using Electron Paramagnetic Resonance and Other Techniques

NASA Astrophysics Data System (ADS)

Zhang, Shigang

Studies of impurities/defects in diamonds grown with the high-temperature high-pressure technique (HTHP) and B- and P-doped diamond films using fast ion implantation and chemical evaporation have been carried out. The main technique employed in the study is electron paramagnetic resonance (EPR). Raman, laser and X-ray fluorescence are also used to characterize the samples. While other commonly used techniques such as infrared (IR) spectroscopy detect no nitrogen in an isotopically enriched ^ {12}C diamond, the clear EPR spectrum consistently measures a nitrogen concentration of about 0.05ppm by calibration against a few standards. The ^{12}C diamond is evaluated to be ideal for optical window application and studies of diamond properties. Neither the EPR lineshape nor the second moment supports a random nitrogen distribution in the ^{12}C diamond. Instead, the average nitrogen distance is found to be larger than the of the random nitrogen distribution. The g-tensor for substitutional nitrogen is found to be axially symmetric along the (111) direction with g_| - g_| = 0.00002(5). In the study of a HTHP IIb blue semiconducting diamond, neutral N is measured with a concentration of 0.02ppm. The result is not well understood since neutral nitrogen is expected to lose its extra electron to boron due to electron-hole recombination. Further studies are suggested to better understand this result. EPR studies of two sets of P-doped diamond films grown using fast ion implantation and chemical incorporation reveal that defect levels caused by diamond doping are still too high for semiconductor applications. As expected, P doping causes a defect level two orders of magnitude higher than B doping, which can be explained by the relatively larger size of P than B. The theoretical analysis based on EPR hyperfine interaction suggest that P forms a shallow donor in diamond and that the electron density at the P site is |psi(0)|^2 = 0.27 times 10^{24} cm^ {-3}. This is consistent with the temperature dependent EPR experimental results. The EPR spectra for all diamond samples I have studied are compared, revealing that the HTHP diamonds show no defect related spectrum, which are commonly observed in natural IIa and IIb diamonds. This result indicates that HTHP diamond has superior quality compared to other diamonds.

Friction and Wear Properties of As-Deposited and Carbon Ion-Implanted Diamond Films

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1996-01-01

Recent work on the friction and wear properties of as-deposited and carbon ion-implanted diamond films was reviewed. Diamond films were produced by the microwave plasma chemical vapor deposition (CVD) technique. Diamond films with various grain sizes and surface roughnesses were implanted with carbon ions at 60 keV ion energy, resulting in a dose of 1.2 x 10(exp 17) carbon ions per cm(exp 2). Various analytical techniques, including Raman spectroscopy, proton recoil analysis, Rutherford backscattering, transmission and scanning electron microscopy, X-ray photoelectron spectroscopy, and X-ray diffraction, were utilized to characterize the diamond films. Sliding friction experiments were conducted with a polished natural diamond pin in contact with diamond films in the three environments: humid air (40% relative humidity), dry nitrogen (less than 1 percent relative humidity), and ultrahigh vacuum (10(exp -7) Pa). The CVD diamond films indeed have friction and wear properties similar to those of natural diamond in the three environments. The as-deposited, fine-grain diamond films can be effectively used as self-lubricating, wear-resistant coatings that have low coefficients of friction (0.02 to 0.04) and low wear rates (10(exp -7) to lO(exp -8) mm(exp 3) N(exp -1) m(exp -1)) in both humid air and dry nitrogen. However, they have high coefficients of friction (1.5 to 1.7) and a high wear rate (10(exp -4) mm(exp 7) N(exp -1) m(exp -1)) in ultrahigh vacuum. The carbon ion implantation produced a thin surficial layer (less than 0.1 micron thick) of amorphous, non-diamond carbon on the diamond films. In humid air and dry nitrogen, the ion-implanted, fine and coarse-grain diamond films have a low coefficient of friction (around 0.1) and a low wear rate (10(exp -7) mm(exp 3) N(exp -1) m(exp-1)). Even in ultrahigh vacuum, the presence of the non-diamond carbon layer reduced the coefficient of friction of fine-grain diamond films to 0.1 or lower and the wear rate to 10(exp -6) mm(exp 3) N(exp -1) m(exp -1). Thus, the carbon ion-implanted, fine-grain diamond films can be effectively used as wear-resistant, self-lubricating coatings not only in air and dry nitrogen, but also in ultrahigh vacuum.

Diamond thin films: giving biomedical applications a new shine

PubMed Central

Nistor, P. A.

2017-01-01

Progress made in the last two decades in chemical vapour deposition technology has enabled the production of inexpensive, high-quality coatings made from diamond to become a scientific and commercial reality. Two properties of diamond make it a highly desirable candidate material for biomedical applications: first, it is bioinert, meaning that there is minimal immune response when diamond is implanted into the body, and second, its electrical conductivity can be altered in a controlled manner, from insulating to near-metallic. In vitro, diamond can be used as a substrate upon which a range of biological cells can be cultured. In vivo, diamond thin films have been proposed as coatings for implants and prostheses. Here, we review a large body of data regarding the use of diamond substrates for in vitro cell culture. We also detail more recent work exploring diamond-coated implants with the main targets being bone and neural tissue. We conclude that diamond emerges as one of the major new biomaterials of the twenty-first century that could shape the way medical treatment will be performed, especially when invasive procedures are required. PMID:28931637

Diamond- cBN alloy: A universal cutting material

DOE PAGES

Wang, Pei; He, Duanwei; Wang, Liping; ...

2015-09-08

Diamond and cubic boron nitride ( cBN) as conventional superhard materials have found widespread industrial applications, but both have inherent limitations. Diamond is not suitable for high-speed cutting of ferrous materials due to its poor chemical inertness, while cBN is only about half as hard as diamond. Because of their affinity in structural lattices and covalent bonding character, diamond and cBN could form alloys that can potentially fill the performance gap. However, the idea has never been demonstrated because samples obtained in the previous studies were too small to be tested for their practical performance. Here, we report the synthesismore » and characterization of transparent bulk diamond- cBN alloy compacts whose diameters (3 mm) are sufficiently large for them to be processed into cutting tools. The testing results show that the diamond- cBN alloy has superior chemical inertness over polycrystalline diamond and higher hardness than single crystal cBN. In conclusion, high-speed cutting tests on hardened steel and granite suggest that diamond- cBN alloy is indeed a universal cutting material.« less

Diamond-cBN alloy: A universal cutting material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Pei; High Pressure Science and Engineering Center and Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, Nevada 89154; He, Duanwei, E-mail: duanweihe@scu.edu.cn

Diamond and cubic boron nitride (cBN) as conventional superhard materials have found widespread industrial applications, but both have inherent limitations. Diamond is not suitable for high-speed cutting of ferrous materials due to its poor chemical inertness, while cBN is only about half as hard as diamond. Because of their affinity in structural lattices and covalent bonding character, diamond and cBN could form alloys that can potentially fill the performance gap. However, the idea has never been demonstrated because samples obtained in the previous studies were too small to be tested for their practical performance. Here, we report the synthesis andmore » characterization of transparent bulk diamond-cBN alloy compacts whose diameters (3 mm) are sufficiently large for them to be processed into cutting tools. The testing results show that the diamond-cBN alloy has superior chemical inertness over polycrystalline diamond and higher hardness than single crystal cBN. High-speed cutting tests on hardened steel and granite suggest that diamond-cBN alloy is indeed a universal cutting material.« less

Diamond- cBN alloy: A universal cutting material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Pei; He, Duanwei; Wang, Liping

Diamond and cubic boron nitride ( cBN) as conventional superhard materials have found widespread industrial applications, but both have inherent limitations. Diamond is not suitable for high-speed cutting of ferrous materials due to its poor chemical inertness, while cBN is only about half as hard as diamond. Because of their affinity in structural lattices and covalent bonding character, diamond and cBN could form alloys that can potentially fill the performance gap. However, the idea has never been demonstrated because samples obtained in the previous studies were too small to be tested for their practical performance. Here, we report the synthesismore » and characterization of transparent bulk diamond- cBN alloy compacts whose diameters (3 mm) are sufficiently large for them to be processed into cutting tools. The testing results show that the diamond- cBN alloy has superior chemical inertness over polycrystalline diamond and higher hardness than single crystal cBN. In conclusion, high-speed cutting tests on hardened steel and granite suggest that diamond- cBN alloy is indeed a universal cutting material.« less

High pressure studies using two-stage diamond micro-anvils grown by chemical vapor deposition

DOE PAGES

Vohra, Yogesh K.; Samudrala, Gopi K.; Moore, Samuel L.; ...

2015-06-10

Ultra-high static pressures have been achieved in the laboratory using a two-stage micro-ball nanodiamond anvils as well as a two-stage micro-paired diamond anvils machined using a focused ion-beam system. The two-stage diamond anvils’ designs implemented thus far suffer from a limitation of one diamond anvil sliding past another anvil at extreme conditions. We describe a new method of fabricating two-stage diamond micro-anvils using a tungsten mask on a standard diamond anvil followed by microwave plasma chemical vapor deposition (CVD) homoepitaxial diamond growth. A prototype two stage diamond anvil with 300 μm culet and with a CVD diamond second stage ofmore » 50 μm in diameter was fabricated. We have carried out preliminary high pressure X-ray diffraction studies on a sample of rare-earth metal lutetium sample with a copper pressure standard to 86 GPa. Furthermore, the micro-anvil grown by CVD remained intact during indentation of gasket as well as on decompression from the highest pressure of 86 GPa.« less

Direct observation of inversion capacitance in p-type diamond MOS capacitors with an electron injection layer

NASA Astrophysics Data System (ADS)

Matsumoto, Tsubasa; Kato, Hiromitsu; Makino, Toshiharu; Ogura, Masahiko; Takeuchi, Daisuke; Yamasaki, Satoshi; Imura, Masataka; Ueda, Akihiro; Inokuma, Takao; Tokuda, Norio

2018-04-01

The electrical properties of Al2O3/p-type diamond (111) MOS capacitors were studied with the goal of furthering diamond-based semiconductor research. To confirm the formation of an inversion layer in the p-type diamond body, an n-type layer for use as a minority carrier injection layer was selectively deposited onto p-type diamond. To form the diamond MOS capacitors, Al2O3 was deposited onto OH-terminated diamond using atomic layer deposition. The MOS capacitor showed clear inversion capacitance at 10 Hz. The minority carrier injection from the n-type layer reached the inversion n-channel diamond MOS field-effect transistor (MOSFET). Using the high-low frequency capacitance method, the interface state density, D it, within an energy range of 0.1-0.5 eV from the valence band edge energy, E v, was estimated at (4-9) × 1012 cm-2 eV-1. However, the high D it near E v remains an obstacle to improving the field effect mobility for the inversion p-channel diamond MOSFET.

Superconductivity in diamond.

PubMed

Ekimov, E A; Sidorov, V A; Bauer, E D; Mel'nik, N N; Curro, N J; Thompson, J D; Stishov, S M

2004-04-01

Diamond is an electrical insulator well known for its exceptional hardness. It also conducts heat even more effectively than copper, and can withstand very high electric fields. With these physical properties, diamond is attractive for electronic applications, particularly when charge carriers are introduced (by chemical doping) into the system. Boron has one less electron than carbon and, because of its small atomic radius, boron is relatively easily incorporated into diamond; as boron acts as a charge acceptor, the resulting diamond is effectively hole-doped. Here we report the discovery of superconductivity in boron-doped diamond synthesized at high pressure (nearly 100,000 atmospheres) and temperature (2,500-2,800 K). Electrical resistivity, magnetic susceptibility, specific heat and field-dependent resistance measurements show that boron-doped diamond is a bulk, type-II superconductor below the superconducting transition temperature T(c) approximately 4 K; superconductivity survives in a magnetic field up to Hc2(0) > or = 3.5 T. The discovery of superconductivity in diamond-structured carbon suggests that Si and Ge, which also form in the diamond structure, may similarly exhibit superconductivity under the appropriate conditions.

A Concurrent Smalltalk Compiler for the Message-Driven Processor

DTIC Science & Technology

1988-05-01

apj with bits from low-bit (inclusive) to high-bit (exclusive) set. ;;;Low-bit defaults to zero. (defmacro brange (high-bit &optional low-bit) (list...n2) (null (cddr num))) (aetg bits (b+ bits (if (>- nl n2) ( brange (1+ nl) n2) ( brange (1+ n2) ni)))) (error "Bad bmap range: -S" flu.)))) (t (error...vlocs) flat ((vlive (b- finst-vllv* mast) *I.( brange firat-context-slot-nun))) (next (inst-next last))) (if (bempty vlive) (delete-module module inat

Effects of plastic bits on the condition and behaviour of captive-reared pheasants.

PubMed

Butler, D A; Davis, C

2010-03-27

Between 2005 and 2007, data were collected from game farms across England and Wales to examine the effects of the use of bits on the physiological condition and behaviour of pheasants. On each site, two pheasant pens kept in the same conditions were randomly allocated to either use bits or not. The behaviour and physiological conditions of pheasants in each treatment pen were assessed on the day of bitting and weekly thereafter until release. Detailed records of feed usage, medications and mortality were also kept. Bits halved the number of acts of bird-on-bird pecking, but they doubled the incidence of headshaking and scratching. Bits caused nostril inflammation and bill deformities in some birds, particularly after seven weeks of age. In all weeks after bitting, feather condition was poorer in non-bitted pheasants than in those fitted with bits. Less than 3 per cent of bitted birds had damaged skin, but in the non-bitted pens this figure increased over time to 23 per cent four weeks later. Feed use and mortality did not differ between bitted and non-bitted birds.

Method of improving field emission characteristics of diamond thin films

DOEpatents

Krauss, A.R.; Gruen, D.M.

1999-05-11

A method of preparing diamond thin films with improved field emission properties is disclosed. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display. 3 figs.

Method of improving field emission characteristics of diamond thin films

DOEpatents

Krauss, Alan R.; Gruen, Dieter M.

1999-01-01

A method of preparing diamond thin films with improved field emission properties. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display.

Synthesis of n-type semiconductor diamond single crystal under high pressure and high temperature

NASA Astrophysics Data System (ADS)

Li, Yong; Li, Shangsheng; Song, Mousheng; She, Yanchao; Wang, Qiang; Guan, Xuemao

2017-12-01

In this paper, diamond single crystal co-doped with sulfur and boron was successfully synthesized at the fixed pressure of 6.0 GPa and temperature range of 1535 K. Sulfur was detected in the co-doped diamond by Fourier Transform Infrared Spectroscopy (FTIR) and the corresponding characteristic peak located at 848 cm-1. Interestingly, Hall effect measurements indicated that the diamond co-doped with sulfur and boron exhibited n-type semiconductor behaviour. Furthermore, the Hall mobility and carrier concentration of the co-doped diamond higher than those of the boron-doping diamond.

Method for machining steel with diamond tools

DOEpatents

Casstevens, J.M.

1984-01-01

The present invention is directed to a method for machine optical quality finishes and contour accuracies of workpieces of carbon-containing metals such as steel with diamond tooling. The wear rate of the diamond tooling is significantly reduced by saturating the atmosphere at the interface of the workpiece and the diamond tool with a gaseous hydrocarbon during the machining operation. The presence of the gaseous hydrocarbon effectively eliminates the deterioration of the diamond tool by inhibiting or preventing the conversion of the diamond carbon to graphite carbon at the point of contact between the cutting tool and the workpiece.

Method for machining steel with diamond tools

DOEpatents

Casstevens, John M.

1986-01-01

The present invention is directed to a method for machining optical quality inishes and contour accuracies of workpieces of carbon-containing metals such as steel with diamond tooling. The wear rate of the diamond tooling is significantly reduced by saturating the atmosphere at the interface of the workpiece and the diamond tool with a gaseous hydrocarbon during the machining operation. The presence of the gaseous hydrocarbon effectively eliminates the deterioration of the diamond tool by inhibiting or preventing the conversion of the diamond carbon to graphite carbon at the point of contact between the cutting tool and the workpiece.

A density functional study of the effect of hydrogen on electronic properties and band discontinuity at anatase TiO2/diamond interface

NASA Astrophysics Data System (ADS)

Wu, Kongping; Liao, Meiyong; Sang, Liwen; Liu, Jiangwei; Imura, Masataka; Ye, Haitao; Koide, Yasuo

2018-04-01

Tailoring the electronic states of the dielectric oxide/diamond interface is critical to the development of next generation semiconductor devices like high-power high-frequency field-effect transistors. In this work, we investigate the electronic states of the TiO2/diamond 2 × 1-(100) interface by using first principles total energy calculations. Based on the calculation of the chemical potentials for the TiO2/diamond interface, it is observed that the hetero-interfaces with the C-OTi configuration or with two O vacancies are the most energetically favorable structures under the O-rich condition and under Ti-rich condition, respectively. The band structure and density of states of both TiO2/diamond and TiO2/H-diamond hetero-structures are calculated. It is revealed that there are considerable interface states at the interface of the anatase TiO2/diamond hetero-structure. By introducing H on the diamond surface, the interface states are significantly suppressed. A type-II alignment band structure is disclosed at the interface of the TiO2/diamond hetero-structure. The valence band offset increases from 0.6 to 1.7 eV when H is introduced at the TiO2/diamond interface.

A perforated diamond anvil cell for high-energy x-ray diffraction of liquids and amorphous solids at high pressure.

PubMed

Soignard, Emmanuel; Benmore, Chris J; Yarger, Jeffery L

2010-03-01

Diamond anvil cells (DACs) are widely used for the study of materials at high pressure. The typical diamonds used are between 1 and 3 mm thick, while the sample contained within the opposing diamonds is often just a few microns in thickness. Hence, any absorbance or scattering from diamond can cause a significant background or interference when probing a sample in a DAC. By perforating the diamond to within 50-100 microm of the sample, the amount of diamond and the resulting background or interference can be dramatically reduced. The DAC presented in this article is designed to study amorphous materials at high pressure using high-energy x-ray scattering (>60 keV) using laser-perforated diamonds. A small diameter perforation maintains structural integrity and has allowed us to reach pressures >50 GPa, while dramatically decreasing the intensity of the x-ray diffraction background (primarily Compton scattering) when compared to studies using solid diamonds. This cell design allows us for the first time measurement of x-ray scattering from light (low Z) amorphous materials. Here, we present data for two examples using the described DAC with one and two perforated diamond geometries for the high-pressure structural studies of SiO(2) glass and B(2)O(3) glass.

Identifying the Source of Gem Diamonds: Requirements for a Certification System

NASA Astrophysics Data System (ADS)

Shigley, J. E.

2002-05-01

Recent civil conflicts in several countries, in which profits from the sales of gem diamonds have supported the rival factions, have forced the jewelry industry to confront the need to certify the geographic sources of gem diamonds. The goals of this program are to prohibit the sale of so-called "conflict diamonds", and to prevent the loss of consumer confidence. Efforts to identify unique characteristics of gem diamonds have been hampered so far by the absence of chemical or physical features that are diagnostic of particular sources, and the lack of a representative collection of diamonds from major producing areas that would be required for a rigorous scientific study. The jewelry industry has therefore adopted plans to track gem diamonds from the mine through the manufacturing process to the consumer. Practical requirements for implementation of such a certification system will be summarized. Any proposed solutions for determining the sources of gem diamonds by some analytical technique, or for following diamonds from the mine, must take into account the annual production of several tens of millions of carats of rough diamonds, which are transformed during manufacturing into several hundreds of millions of polished gemstones (with an average weight of only about 0.03 carat, or 0.006 gram).

Tailoring nanocrystalline diamond coated on titanium for osteoblast adhesion.

PubMed

Pareta, Rajesh; Yang, Lei; Kothari, Abhishek; Sirinrath, Sirivisoot; Xiao, Xingcheng; Sheldon, Brian W; Webster, Thomas J

2010-10-01

Diamond coatings with superior chemical stability, antiwear, and cytocompatibility properties have been considered for lengthening the lifetime of metallic orthopedic implants for over a decade. In this study, an attempt to tailor the surface properties of diamond films on titanium to promote osteoblast (bone forming cell) adhesion was reported. The surface properties investigated here included the size of diamond surface features, topography, wettability, and surface chemistry, all of which were controlled during microwave plasma enhanced chemical-vapor-deposition (MPCVD) processes using CH4-Ar-H2 gas mixtures. The hardness and elastic modulus of the diamond films were also determined. H2 concentration in the plasma was altered to control the crystallinity, grain size, and topography of the diamond coatings, and specific plasma gases (O2 and NH3) were introduced to change the surface chemistry of the diamond coatings. To understand the impact of the altered surface properties on osteoblast responses, cell adhesion tests were performed on the various diamond-coated titanium. The results revealed that nanocrystalline diamond (grain sizes <100 nm) coated titanium dramatically increased surface hardness, and the introduction of O2 and NH3 during the MPCVD process promoted osteoblast adhesion on diamond and, thus, should be further studied for improving orthopedic applications. Copyright 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

Homoepitaxial Boron Doped Diamond Anvils as Heating Elements in a Diamond Anvil Cell

NASA Astrophysics Data System (ADS)

Montgomery, Jeffrey; Samudrala, Gopi; Smith, Spencer; Tsoi, Georgiy; Vohra, Yogesh; Weir, Samuel

2013-03-01

Recent advances in designer-diamond technology have allowed for the use of electrically and thermally conducting homoepitaxially-grown layers of boron-doped diamond (grown at 1200 °C with a 2% mixture of CH4 in H, resulting in extremely high doping levels ~ 1020/cm3) to be used as heating elements in a diamond anvil cell (DAC). These diamonds allow for precise control of the temperature inside of the diamond anvil itself, particularly when coupled with a cryostat. Furthermore, the unmatched thermally conducting nature of diamond ensures that no significant lateral gradient in temperature occurs across the culet area. Since a thermocouple can easily be attached anywhere on the diamond surface, we can also measure diamond temperatures directly. With two such heaters, one can raise sample temperatures uniformly, or with any desired gradient along the pressure axis while preserving optical access. In our continuing set of benchmark experiments, we use two newly created matching heater anvils with 500 μm culets to analyze the various fluorescence emission lines of ruby microspheres, which show more complicated behavior than traditional ruby chips. We also report on the temperature dependence of the high-pressure Raman modes of paracetamol (C8H9NO2) up to 20 GPa.

Diamonds, a resource curse? The case of Kono District in Sierra Leone

NASA Astrophysics Data System (ADS)

Wilson, Sigismond Ayodele

Using an actor-oriented approach to political ecology integrated with theory on the social production of scale, this dissertation examines the extent to which diamond exploitation constitutes a resource curse in Sierra Leone, with Kono District as a case-study. It uses social survey methods and remote sensing analysis of Landsat images to (1) evaluate the role of Sierra Leone's diamonds in economic development from a historical lens, (2) examine the extent to which a weak regulatory state apparatus makes a rich diamond endowment more of a curse than a blessing, (3) determine whether geographically diffuse and remotely-located diamonds are more a liability than an asset, and (4) assess whether environmental conditions are worse in diamond than in non-diamond chiefdoms. Results of the study showed that the contribution of diamonds to national economic growth declined precipitously following the politicization of diamonds and growing informalization of mining under the leadership of Siaka Stevens. Growing disenchantment combined with grievances over access to diamond resources and rights, culminating in a civil war fuelled by conflict diamonds. Findings indicated that actors capitalized on a weak regulatory state to fulfill their agendas. Illicit diamond exploitation was mainly driven by corruption, economic constraints and perverse economic incentives. Preferential land allocation to industrial mining following World Bank Group-directed national mining policy reforms and the weakness of the state in ensuring companies' adherence to mining clauses precipitated corporation-community conflicts. Study findings showed that the resource curse was acute on diggers who received less than 1 a day unlike their South American counterparts who made at least 7 daily. Results from the study demonstrate that the spatiality of diamonds also contributed to the resource curse. Illicit diamond mining was more acute in remotely located mining sites than in extractive sites closer to towns, and spatial proximity to Guinea and Liberia facilitated diamond smuggling. Remote sensing analysis and social surveys revealed that negative environmental impacts were more manifested in the diamond mining chiefdoms than in non-mining areas, confirming the environment as major dimensions of the resource curse. The environmental impacts of diamond mining had broader implications as the forest, land, and water were affected. Transformation of fertile lands (wetlands) to mining lands, and without required reclamation, had negative consequences on the agricultural productivity of local residents in mining areas. Examination of power relations constituted the pros and cons of managing diamond exploitation. Policy makers should employ broad-based strategies to empower mining communities so that they can elect credible local governments. Clearly demarcated industrial and artisanal mining zones and equity and transparency in the distribution of mineral revenues could minimize potential conflicts between corporations and mining companies.

FOSREM - Fibre-Optic System for Rotational Events&Phenomena Monitoring

NASA Astrophysics Data System (ADS)

Jaroszewicz, Leszek; Krajewski, Zbigniew; Kurzych, Anna; Kowalski, Jerzy; Teisseyre, Krzysztof

2016-04-01

We present the construction and tests of fiber-optic rotational seismometer named FOSREM (Fibre-Optic System for Rotational Events&Phenomena Monitoring). This presented device is designed for detection and monitoring the one-axis rotational motions, brought about to ground or human-made structures both by seismic events and the creep processes. The presented system works by measuring Sagnac effect and generally consists of two basic elements: optical sensor and electronic part. The optical sensor is based on so-called the minimum configuration of FOG (Fibre-Optic Gyroscope) where the Sagnac effect produces a phase shift between two counter-propagating light beams proportional to the measured rotation speed. The main advantage of the sensor of this type is its complete insensitivity to linear motions and a direct measurement of rotational speed. It may work even when tilted, moreover, used in continuous mode it may record the tilt. The electronic system, involving specific electronic solutions, calculates and records rotational events data by realizing synchronous in a digital form by using 32 bit DSP (Digital Signal Processing). Storage data and system control are realised over the internet by using connection between FOSREM and GSM/GPS. The most significant attribute of our system is possibility to measure rotation in wide range both amplitude up to 10 rad/s and frequency up to 328.12 Hz. Application of the wideband, low coherence and high power superluminescent diode with long fibre loop and suitable low losses optical elements assures the theoretical sensitivity of the system equal to 2·10-8 rad/s/Sqrt(Hz). Moreover, the FOSREM is fully remote controlled as well as is suited for continuous, autonomous work in very long period of time (weeks, months, even years), so it is useful for systematic seismological investigation at any place. Possible applications of this system include seismic monitoring in observatories, buildings, mines and even on glaciers and in their vicinity. In geodetic, geomorphological and glaciological survey, joint measurement of tilt and seismic phenomena using a set of three FOSREM devices oriented in perpendicular planes would enable to collect very important information.

Super-deep diamond genesis at Redox conditions of slab-mantle boundary

NASA Astrophysics Data System (ADS)

Gao, J.; Chen, B.; Wu, X.

2017-12-01

Diamond genesis is an intriguing issue for diamond resources and the deep carbon cycle of the Earth's interiors. Super-deep diamonds, representing only 6% of the global diamond population, often host inclusions with phase assemblages requiring a sublithospheric origin (>300 km). Being the windows for probing the deep Earth, super-deep diamonds with their distinctive micro-inclusions not only record a history of oceanic lithosphere subduction and upward transport at a depth of >250 km to even 1000 km, but indicate their genesis pertinent to mantle-carbonate melts in a Fe0-bufferred reduced condition. Our pilot experiments have evidenced the formation of diamonds from MgCO3-Fe0 system in a diamond anvil cell device at 25 GPa and 1800 K. Detailed experimental investigations of redox mechanism of MgCO3-Fe0 and CaCO3-Fe0 coupling have been conducted using multi-anvil apparatus. The conditions are set along the oceanic lithosphere subduction paths in the pressure-temperature range of 10-24 GPa and 1200-2000 K, covering the formation region of most super-deep diamonds. The clear reaction zones strongly support the redox reaction between carbonatitic slab and Fe0-bearing metals under mantle conditions. Our study has experimentally documented the possibility of super-deep diamond genesis at redox conditions of carbonateitic slab and Fe0-bearings. The kinetics of diamond formation as a function of pressure-temperature conditions are also discussed.

Designer Diamonds: Applications in Iron-based Superconductors and Lanthanides

NASA Astrophysics Data System (ADS)

Vohra, Yogesh

2013-06-01

This talk will focus on the recent progress in the fabrication of designer diamond anvils as well as scientific applications of these diamonds in static high pressure research. The two critical parameters that have emerged in the microwave plasma chemical vapor deposition of designer diamond anvils are (1) the precise [100] alignment of the starting diamond substrate and (2) balancing the competing roles of parts per million levels of nitrogen and oxygen in the diamond growth plasma. The control of these parameters results in the fabrication of high quality designer diamonds with culet size in excess of 300 microns in diameter. The three different applications of designer diamond anvils will be discussed (1) simultaneous electrical resistance and crystal structure measurements using a synchrotron source on Iron-based superconductors with data on both electron and hole doped BaFe2As2 materials and other novel superconducting materials (2) high-pressure high-temperature melting studies on metals using eight-probe Ohmic heating designer diamonds and (3) high pressure low temperature studies on magnetic behavior of 4f-lanthanide metals using four-probe electrical resistance measurements and complementary neutron diffraction studies on a spallation neutron source. Future opportunities in boron-doped conducting designer diamond anvils as well as fabrication of two-stage designer diamonds for ultra high pressure experiments will also be presented. This work was supported by the Department of Energy (DOE) - National Nuclear Security Administration (NNSA) under Grant No. DE-FG52-10NA29660.

Critique of a Hughes shuttle Ku-band data sampler/bit synchronizer

NASA Technical Reports Server (NTRS)

Holmes, J. K.

1980-01-01

An alternative bit synchronizer proposed for shuttle was analyzed in a noise-free environment by considering the basic operation of the loop via timing diagrams and by linearizing the bit synchronizer as an equivalent, continuous, phased-lock loop (PLL). The loop is composed of a high-frequency phase-frequency detector which is capable of detecting both phase and frequency errors and is used to track the clock, and a bit transition detector which attempts to track the transitions of the data bits. It was determined that the basic approach was a good design which, with proper implementation of the accumulator, up/down counter and logic should provide accurate mid-bit sampling with symmetric bits. However, when bit asymmetry occurs, the bit synchronizer can lock up with a large timing error, yet be quasi-stable (timing will not change unless the clock and bit sequence drift). This will result in incorrectly detecting some bits.

Structures and Mechanical Properties of Natural and Synthetic Diamonds. Chapter 8

NASA Technical Reports Server (NTRS)

Miyoshi, Kazuhisa

1998-01-01

A revolution in diamond technology is in progress as the low-pressure process becomes an industrial reality. It will soon be possible to take advantage of the demanding properties of diamond to develop a myriad of new applications, particularly for self-lubricating, wear, and superhard coatings. The production of large diamond films or sheets at low cost, a distinct possibility in the not-too-distant future, may drastically change tribology technology, particularly solid lubricants and lubricating materials and systems. This chapter reviews the structures and properties of natural and synthetic diamond to gain a better understanding of the tribological properties of diamond and related materials to be described in the following chapters. Atomic and crystal structure, impurities, mechanical properties, and indentation hardness of diamond are described.

[Spectroscopic studies on transition metal ions in colored diamonds].

PubMed

Meng, Yu-Fei; Peng, Ming-Sheng

2004-07-01

Transition metals like nickel, cobalt and iron have been often used as solvent catalysts in high pressure high temperature (HPHT) synthesis of diamond, and nickel and cobalt ions have been found in diamond lattice. Available studies indicated that nickel and cobalt ions could enter the lattice as interstitial or substitutional impurities and form complexes with nitrogen. Polarized microscopy, SEM-EDS, EPR, PL and FTIR have been used in this study to investigate six fancy color natural and synthetic diamonds in order to determine the spectroscopic characteristics and the existing forms of transition metal ions in colored diamond lattice. Cobalt-related optical centers were first found in natural chameleon diamonds, and some new nickel and cobalt-related optical and EPR centers have also been detected in these diamond samples.

New diamond cell for single-crystal x-ray diffraction

NASA Astrophysics Data System (ADS)

Boehler, Reinhard

2006-11-01

A new design for a high-precision diamond cell is described. Two kinematically mounted steel disks are elastically deflected to generate pressure. This principle provides higher precision in the diamond anvil alignment than most sliding piston-cylinder or guide-pin devices at significantly lower cost. With this new diamond cell conical diamond anvils with an x-ray aperture of 85° were successfully tested to over 50GPa using helium as a pressure medium. Anvil thickness of less than 1.4mm provides high x-ray transmission and low background, a significant improvement compared to beryllium or diamond-disk backing plates. Because the diamond anvils are supported by tungsten carbide seats, samples and pressure media can be annealed by external or laser heating to provide hydrostatic pressure conditions.

A methodology for conducting national-scale alluvial diamond resource potential and production capacity assessments, with a focus on artisanal mining

USGS Publications Warehouse

Chirico, Peter G.; Malpeli, Katherine C.

2012-01-01

In May of 2000, a meeting was convened in Kimberley, South Africa, by representatives of the diamond industry and leaders of African governments to develop a certification process intended to assure that export shipments of rough diamonds were free of conflict concerns. Outcomes of the meeting were formally supported later in December of 2000 by the United Nations in a resolution adopted by the General Assembly. By 2002, the Kimberley Process Certification Scheme was ratified and signed by diamond-producing and diamond-importing countries. As of August 2012, the Kimberley Process (KP) had 51 participants representing 77 countries. It is often difficult to obtain independent verification of the diamond production statistics that are provided to the KP. However, some degree of independent verification can be obtained through an understanding of a country’s naturally occurring endowment of diamonds and the intensity of mining activities. Studies that integrate these two components can produce a range of estimated values for a country’s diamond production, and these estimates can then be compared to the production statistics released by that country. This methodology is used to calculate (1) the diamond resource potential of a country, which refers to the total number of carats estimated to be remaining in the country, and (2) the diamond production capacity of a country, which is the current volume of diamonds that may realistically be produced per year utilizing current human and physical resources. The following sections outline the methodology used by the U.S. Geological Survey (USGS) to perform diamond assessments in Mali, the Central African Republic, Ghana, and Guinea.

Contract W911NF-12-C-0102 (Advanced Diamond Technologies, Inc.)

DTIC Science & Technology

2013-06-24

resistivity, residual stress and Raman spectra measurement is finished. Raman spectra shows basically regular nanocrystalline diamond signature as expected...diamond films including thickness, resistivity, residual stress and Raman spectra measurement is finished. Raman spectra shows basically regular...15743 WF600B05 3000 0.02 0.03 0.0018 4 Fig. 2 Raman spectra (λ=532 nm) of (a) all diamond with different doping level and (b) diamond only with

Industrial diamond

USGS Publications Warehouse

Olson, D.W.

2012-01-01

Estimated 2011 world production of natural and synthetic industrial diamond was about 4.45 billion carats. During 2011, natural industrial diamonds were produced in more than 20 countries, and synthetic industrial diamond was produced in at least 13 countries. About 98 percent of the combined natural and synthetic global output was produced in China, Ireland, Japan, Russia, South Africa and the United States. China is the world's leading producer of synthetic industrial diamond followed by Russia and the United States.

Uncovering the Physical Basis Connecting Environment and Tribological Performance of Ultrananocrystalline Diamond

DTIC Science & Technology

2014-04-17

measured with an infrared pyrometer (550-3200°C). The substrates were coated with diamond nanoparticles (ITC Inc.) which serve as nucleation sites...wafers were seeded with nano-diamond particles prior to film growth to provide nucleation sites for diamond growth. To study the effect of surface...wafers are appropriate to generate uniform seeding. AFM tips were seeded with nano-diamond particles prior to coating with NCD to provide nucleation

Bit-1 is an essential regulator of myogenic differentiation

PubMed Central

Griffiths, Genevieve S.; Doe, Jinger; Jijiwa, Mayumi; Van Ry, Pam; Cruz, Vivian; de la Vega, Michelle; Ramos, Joe W.; Burkin, Dean J.; Matter, Michelle L.

2015-01-01

Muscle differentiation requires a complex signaling cascade that leads to the production of multinucleated myofibers. Genes regulating the intrinsic mitochondrial apoptotic pathway also function in controlling cell differentiation. How such signaling pathways are regulated during differentiation is not fully understood. Bit-1 (also known as PTRH2) mutations in humans cause infantile-onset multisystem disease with muscle weakness. We demonstrate here that Bit-1 controls skeletal myogenesis through a caspase-mediated signaling pathway. Bit-1-null mice exhibit a myopathy with hypotrophic myofibers. Bit-1-null myoblasts prematurely express muscle-specific proteins. Similarly, knockdown of Bit-1 expression in C2C12 myoblasts promotes early differentiation, whereas overexpression delays differentiation. In wild-type mice, Bit-1 levels increase during differentiation. Bit-1-null myoblasts exhibited increased levels of caspase 9 and caspase 3 without increased apoptosis. Bit-1 re-expression partially rescued differentiation. In Bit-1-null muscle, Bcl-2 levels are reduced, suggesting that Bcl-2-mediated inhibition of caspase 9 and caspase 3 is decreased. Bcl-2 re-expression rescued Bit-1-mediated early differentiation in Bit-1-null myoblasts and C2C12 cells with knockdown of Bit-1 expression. These results support an unanticipated yet essential role for Bit-1 in controlling myogenesis through regulation of Bcl-2. PMID:25770104

Mechanism-Based FE Simulation of Tool Wear in Diamond Drilling of SiCp/Al Composites.

PubMed

Xiang, Junfeng; Pang, Siqin; Xie, Lijing; Gao, Feinong; Hu, Xin; Yi, Jie; Hu, Fang

2018-02-07

The aim of this work is to analyze the micro mechanisms underlying the wear of macroscale tools during diamond machining of SiC p /Al6063 composites and to develop the mechanism-based diamond wear model in relation to the dominant wear behaviors. During drilling, high volume fraction SiC p /Al6063 composites containing Cu, the dominant wear mechanisms of diamond tool involve thermodynamically activated physicochemical wear due to diamond-graphite transformation catalyzed by Cu in air atmosphere and mechanically driven abrasive wear due to high-frequency scrape of hard SiC reinforcement on tool surface. An analytical diamond wear model, coupling Usui abrasive wear model and Arrhenius extended graphitization wear model was proposed and implemented through a user-defined subroutine for tool wear estimates. Tool wear estimate in diamond drilling of SiC p /Al6063 composites was achieved by incorporating the combined abrasive-chemical tool wear subroutine into the coupled thermomechanical FE model of 3D drilling. The developed drilling FE model for reproducing diamond tool wear was validated for feasibility and reliability by comparing numerically simulated tool wear morphology and experimentally observed results after drilling a hole using brazed polycrystalline diamond (PCD) and chemical vapor deposition (CVD) diamond coated tools. A fairly good agreement of experimental and simulated results in cutting forces, chip and tool wear morphologies demonstrates that the developed 3D drilling FE model, combined with a subroutine for diamond tool wear estimate can provide a more accurate analysis not only in cutting forces and chip shape but also in tool wear behavior during drilling SiC p /Al6063 composites. Once validated and calibrated, the developed diamond tool wear model in conjunction with other machining FE models can be easily extended to the investigation of tool wear evolution with various diamond tool geometries and other machining processes in cutting different workpiece materials.

Mechanism-Based FE Simulation of Tool Wear in Diamond Drilling of SiCp/Al Composites

PubMed Central

Xiang, Junfeng; Pang, Siqin; Xie, Lijing; Gao, Feinong; Hu, Xin; Yi, Jie; Hu, Fang

2018-01-01

The aim of this work is to analyze the micro mechanisms underlying the wear of macroscale tools during diamond machining of SiCp/Al6063 composites and to develop the mechanism-based diamond wear model in relation to the dominant wear behaviors. During drilling, high volume fraction SiCp/Al6063 composites containing Cu, the dominant wear mechanisms of diamond tool involve thermodynamically activated physicochemical wear due to diamond-graphite transformation catalyzed by Cu in air atmosphere and mechanically driven abrasive wear due to high-frequency scrape of hard SiC reinforcement on tool surface. An analytical diamond wear model, coupling Usui abrasive wear model and Arrhenius extended graphitization wear model was proposed and implemented through a user-defined subroutine for tool wear estimates. Tool wear estimate in diamond drilling of SiCp/Al6063 composites was achieved by incorporating the combined abrasive-chemical tool wear subroutine into the coupled thermomechanical FE model of 3D drilling. The developed drilling FE model for reproducing diamond tool wear was validated for feasibility and reliability by comparing numerically simulated tool wear morphology and experimentally observed results after drilling a hole using brazed polycrystalline diamond (PCD) and chemical vapor deposition (CVD) diamond coated tools. A fairly good agreement of experimental and simulated results in cutting forces, chip and tool wear morphologies demonstrates that the developed 3D drilling FE model, combined with a subroutine for diamond tool wear estimate can provide a more accurate analysis not only in cutting forces and chip shape but also in tool wear behavior during drilling SiCp/Al6063 composites. Once validated and calibrated, the developed diamond tool wear model in conjunction with other machining FE models can be easily extended to the investigation of tool wear evolution with various diamond tool geometries and other machining processes in cutting different workpiece materials. PMID:29414839

The Effect of ZrO₂ Nanoparticles on the Microstructure and Properties of Sintered WC-Bronze-Based Diamond Composites.

PubMed

Sun, Youhong; Wu, Haidong; Li, Meng; Meng, Qingnan; Gao, Ke; Lü, Xiaoshu; Liu, Baochang

2016-05-06

Metal matrix-impregnated diamond composites are widely used in diamond tool manufacturing. In order to satisfy the increasing engineering requirements, researchers have paid more and more attention to enhancing conventional metal matrices by applying novel methods. In this work, ZrO₂ nanoparticles were introduced into the WC-bronze matrix with and without diamond grits via hot pressing to improve the performance of conventional diamond composites. The effects of ZrO₂ nanoparticles on the microstructure, density, hardness, bending strength, and wear resistance of diamond composites were investigated. The results indicated that the hardness and relative density increased, while the bending strength decreased when the content of ZrO₂ nanoparticles increased. The grinding ratio of diamond composites increased significantly by 60% as a result of nano-ZrO₂ addition. The enhancement mechanism was discussed. Diamond composites showed the best overall properties with the addition of 1 wt % ZrO₂ nanoparticles, thus paving the way for further applications.

The Effect of ZrO2 Nanoparticles on the Microstructure and Properties of Sintered WC–Bronze-Based Diamond Composites

PubMed Central

Sun, Youhong; Wu, Haidong; Li, Meng; Meng, Qingnan; Gao, Ke; Lü, Xiaoshu; Liu, Baochang

2016-01-01

Metal matrix-impregnated diamond composites are widely used in diamond tool manufacturing. In order to satisfy the increasing engineering requirements, researchers have paid more and more attention to enhancing conventional metal matrices by applying novel methods. In this work, ZrO2 nanoparticles were introduced into the WC–bronze matrix with and without diamond grits via hot pressing to improve the performance of conventional diamond composites. The effects of ZrO2 nanoparticles on the microstructure, density, hardness, bending strength, and wear resistance of diamond composites were investigated. The results indicated that the hardness and relative density increased, while the bending strength decreased when the content of ZrO2 nanoparticles increased. The grinding ratio of diamond composites increased significantly by 60% as a result of nano-ZrO2 addition. The enhancement mechanism was discussed. Diamond composites showed the best overall properties with the addition of 1 wt % ZrO2 nanoparticles, thus paving the way for further applications. PMID:28773469

Thermal conductivity of ultrathin nano-crystalline diamond films determined by Raman thermography assisted by silicon nanowires

NASA Astrophysics Data System (ADS)

Anaya, Julian; Rossi, Stefano; Alomari, Mohammed; Kohn, Erhard; Tóth, Lajos; Pécz, Béla; Kuball, Martin

2015-06-01

The thermal transport in polycrystalline diamond films near its nucleation region is still not well understood. Here, a steady-state technique to determine the thermal transport within the nano-crystalline diamond present at their nucleation site has been demonstrated. Taking advantage of silicon nanowires as surface temperature nano-sensors, and using Raman Thermography, the in-plane and cross-plane components of the thermal conductivity of ultra-thin diamond layers and their thermal barrier to the Si substrate were determined. Both components of the thermal conductivity of the nano-crystalline diamond were found to be well below the values of polycrystalline bulk diamond, with a cross-plane thermal conductivity larger than the in-plane thermal conductivity. Also a depth dependence of the lateral thermal conductivity through the diamond layer was determined. The results impact the design and integration of diamond for thermal management of AlGaN/GaN high power transistors and also show the usefulness of the nanowires as accurate nano-thermometers.

Effect of electronic structure of the diamond surface on the strength of the diamond-metal interface

NASA Technical Reports Server (NTRS)

Pepper, S. V.

1981-01-01

A diamond surface undergoes a transformation in its electronic structure by a vacuum anneal at approximately 900 C. The polished surface has no electronic states in the band gap, whereas the annealed surface has both occupied and unoccupied states in the and gap and exhibits some electrical conductivity. The effect of this transformation on the strength of the diamond metal interface was investigated by measuring the static friction force of an atomically clean meta sphere on a diamond flat in ultrahigh vacuum. It was found that low friction (weak bonding) is associated with the diamond surface devoid of gap states whereas high friction (strong bonding) is associated with the diamond surface with gap states. Exposure of the annealed surface to excited hydrogen also leads to weak bonding. The interfacial bond is discussed in terms of interaction of the metal conduction band electrons with the band gap states on the diamond surface. Effects of surface electrical conductivity on the interfacial bond are also be considered.

Effect of added dispersants on diamond particles in Ni-diamond composites fabricated with electrodeposition

NASA Astrophysics Data System (ADS)

Choi, Yongje; Kim, Donghyun; Son, Kyungsik; Lee, Sanghyuk; Chung, Wonsub

2015-11-01

The electrodeposition of Ni-diamond composites was investigated to improve the dispersion and adhesion of the diamond particles, and thus, increase the performance of cutting tools. The additives, so called firstclass brighteners, benzoic sulfimide, benzene sulfonamide, and benzene sulfonic acid were used as dispersants to enhance the dispersivity of diamond particles. The dispersivity was analyzed with Image-Pro software, which was used to asses optical microscopy images, and the number of individual diamond particles and area fraction were calculated. In addition, electrochemical tests were performed, including zeta potential and galvanostatic measurements, and the adhesion strengths was tested by evaluating the wear resistance using ball-on-disk tester. The dispersion and adhesion of the diamond particles were improved when benzoic sulfimide was added to the composite plating bath at a concentration of 0.06 g/L. The number of individual diamond particles was 56 EA/mm2, and the weight loss of alumina ball and specimen was 2.88 mg and 0.80 mg, respectively.

Orapa Diamond Mine, Botswana

NASA Image and Video Library

2015-11-16

This image from NASA Terra spacecraft shows the Orapa diamond mine, the world largest diamond mine by area. The mine is located in Botswana. It is the oldest of four mines operated by the same company, having begun operations in 1971. Orapa is an open pit style of mine, located on two kimberlite pipes. Currently, the Orapa mine annually produces approximately 11 million carats (2200 kg) of diamonds. The Letlhakane diamond mine is also an open pit construction. In 2003, the Letlhakane mine produced 1.06 million carats of diamonds. The Damtshaa diamond mine is the newest of four mines, located on top of four distinct kimberlite pipes of varying ore grade. The mine is forecast to produce about 5 million carats of diamond over the projected 31 year life of the mine. The image was acquired October 5, 2014, covers an area of 28 by 45 km, and is located at 21.3 degrees south, 25.4 degrees east. http://photojournal.jpl.nasa.gov/catalog/PIA20104

High-Q/V Monolithic Diamond Microdisks Fabricated with Quasi-isotropic Etching.

PubMed

Khanaliloo, Behzad; Mitchell, Matthew; Hryciw, Aaron C; Barclay, Paul E

2015-08-12

Optical microcavities enhance light-matter interactions and are essential for many experiments in solid state quantum optics, optomechanics, and nonlinear optics. Single crystal diamond microcavities are particularly sought after for applications involving diamond quantum emitters, such as nitrogen vacancy centers, and for experiments that benefit from diamond's excellent optical and mechanical properties. Light-matter coupling rates in experiments involving microcavities typically scale with Q/V, where Q and V are the microcavity quality-factor and mode-volume, respectively. Here we demonstrate that microdisk whispering gallery mode cavities with high Q/V can be fabricated directly from bulk single crystal diamond. By using a quasi-isotropic oxygen plasma to etch along diamond crystal planes and undercut passivated diamond structures, we create monolithic diamond microdisks. Fiber taper based measurements show that these devices support TE- and TM-like optical modes with Q > 1.1 × 10(5) and V < 11(λ/n) (3) at a wavelength of 1.5 μm.

Finishing of display glass for mobile electronics using 3M Trizact diamond tile abrasive pads

NASA Astrophysics Data System (ADS)

Zheng, Lianbin; Fletcher, Tim; Na, Tee Koon; Sventek, Bruce; Romero, Vince; Lugg, Paul S.; Kim, Don

2010-10-01

This paper will describe a new method being used during the finishing of glass displays for mobile electronics including mobile hand held devices and notebook computers. The new method consists of using 3M TrizactTM Diamond Tile Abrasive Pads. TrizactTM Diamond Tile is a structured fixed abrasive grinding technology developed by 3M Company. The TrizactTM Diamond Tile structured abrasive pad consists of an organic (polymeric binder) - inorganic (abrasive mineral, i.e., diamond) composite that is used with a water-based coolant. TrizactTM Diamond Tile technology can be applied in both double and single side grinding applications. A unique advantage of TrizactTM Diamond Tile technology is the combination of high stock removal and low sub-surface damage. Grinding results will be presented for both 9 micron and 20 micron grades of TrizactTM Diamond Tile abrasive pads used to finish several common display glasses including Corning GorillaTM glass and Soda Lime glass.

The uniquely high-temperature character of Cullinan diamonds: A signature of the Bushveld mantle plume?

NASA Astrophysics Data System (ADS)

Korolev, N. M.; Kopylova, M.; Bussweiler, Y.; Pearson, D. G.; Gurney, J.; Davidson, J.

2018-04-01

The mantle beneath the Cullinan kimberlite (formerly known as "Premier") is a unique occurrence of diamondiferous cratonic mantle where diamonds were generated contemporaneously and shortly following a mantle upwelling that led to the formation of a Large Igneous Province that produced the world's largest igneous intrusion - the 2056 Ma Bushveld Igneous Complex (BIC). We studied 332 diamond inclusions from 202 Cullinan diamonds to investigate mantle thermal effects imposed by the formation of the BIC. The overwhelming majority of diamonds come from three parageneses: (1) lithospheric eclogitic (69%), (2) lithospheric peridotitic (21%), and (3) sublithospheric mafic (9%). The lithospheric eclogitic paragenesis is represented by clinopyroxene, garnet, coesite and kyanite. Main minerals of the lithospheric peridotitic paragenesis are forsterite, enstatite, Cr-pyrope, Cr-augite and spinel; the sublithospheric mafic association includes majorite, CaSiO3 phases and omphacite. Diamond formation conditions were calculated using an Al-in-olivine thermometer, a garnet-clinopyroxene thermometer, as well as majorite and Raman barometers. The Cullinan diamonds may be unique on the global stage in recording a cold geotherm of 40 mW/m2 in cratonic lithosphere that was in contact with underlying convecting mantle at temperatures of 1450-1550 °C. The studied Cullinan diamonds contain a high proportion of inclusions equilibrated at temperatures exceeding the ambient 1327 °C adiabat, i.e. 54% of eclogitic diamonds and 41% of peridotitic diamonds. By contrast, ≤ 1% of peridotitic diamond inclusions globally yield equally high temperatures. We propose that the Cullinan diamond inclusions recorded transient, slow-dissipating thermal perturbations associated with the plume-related formation of the 2 Ga Bushveld igneous province. The presence of inclusions in diamond from the mantle transition zone at 300-650 km supports this view. Cullinan xenoliths indicative of the thermal state of the cratonic lithosphere at 1.2 Ga are equilibrated at the relatively low temperatures, not exceeding adiabatic. The ability of diamonds to record super-adiabatic temperatures may relate to their entrainment from the deeper, hotter parts of the upper mantle un-sampled by the kimberlite in the form of xenoliths or their equilibration in a younger lithosphere after a decay of the thermal disturbance.

Infrared spectral and carbon isotopic characteristics of micro- and macro-diamonds from the Panda kimberlite (Central Slave Craton, Canada)

NASA Astrophysics Data System (ADS)

Melton, G. L.; Stachel, T.; Stern, R. A.; Carlson, J.; Harris, J. W.

2013-09-01

One hundred and twenty-one micro-diamonds (< 1 mm) and 90 macro-diamonds (2.5 mm to 3.4 mm) from the Panda kimberlite (Ekati mine, Central Slave Craton, Canada) were analyzed for nitrogen content, nitrogen aggregation state (%B) and platelet and hydrogen peak areas (cm- 2). Micro-diamond nitrogen concentrations range from < 10 at. ppm to 1696 at. ppm (median = 805 at. ppm) and the median aggregation state is 23%B. Macro-diamonds range from < 10 at. ppm to 1260 at. ppm (median = 187 at. ppm) nitrogen and have a median nitrogen aggregation of 26%B. Platelet and hydrogen peaks were observed in 37% and 79% of the micro-diamonds and 79% and 56% of the macro-diamonds, respectively. Nitrogen based time averaged residence temperatures indicate that micro- and macro-diamonds experienced similar thermal mantle residence histories, both populations displaying bimodal residence temperature distributions with a gap between 1130 °C and 1160 °C (at 3.5 Ga residence). In addition, SIMS carbon isotopic analyses for the micro-diamonds were obtained: δ13C compositions range from - 6.9‰ to + 1.8‰ (median = - 4.3‰). CL imaging reveals distinct growth layers that in some samples differ by > 2‰, but mostly vary by < 0.5‰. Comparison of only the “gem-quality” samples (n = 49 micro- and 90 macro-diamonds) between the two diamond sets, indicates a statistically significant shift of + 1.3‰ in average δ13C from macro- to micro-diamonds and this shift documents distinct diamond forming fluids, fractionation process or growth histories. A broad transition to heavier isotopic values is also observed in connection to decreasing mantle residence temperatures. The bimodal mantle residence temperature distribution may coincide with the transition from highly depleted shallow to more fertile deep lithospheric mantle observed beneath the Central Slave Craton. The increase in δ13C with decreasing residence temperature (proxy for decreasing depth) is interpreted to reflect diamond formation from a carbonate-bearing metasomatic fluid/melt that isotopically evolves as it percolates upward through the lithosphere.

Rapid Access Ice Drill: A New Tool for Exploration of the Deep Antarctic Ice Sheets and Subglacial Geology

NASA Astrophysics Data System (ADS)

Goodge, J. W.; Severinghaus, J. P.

2014-12-01

The Rapid Access Ice Drill (RAID) will penetrate the Antarctic ice sheets in order to core through deep ice, the glacial bed, and into bedrock below. This new technology will provide a critical first look at the interface between major ice caps and their subglacial geology. Currently in construction, RAID is a mobile drilling system capable of making several long boreholes in a single field season in Antarctica. RAID is interdisciplinary and will allow access to polar paleoclimate records in ice >1 Ma, direct observation at the base of the ice sheets, and recovery of rock cores from the ice-covered East Antarctic craton. RAID uses a diamond rock-coring system as in mineral exploration. Threaded drill-pipe with hardened metal bits will cut through ice using reverse circulation of Estisol for pressure-compensation, maintenance of temperature, and removal of ice cuttings. Near the bottom of the ice sheet, a wireline bottom-hole assembly will enable diamond coring of ice, the glacial bed, and bedrock below. Once complete, boreholes will be kept open with fluid, capped, and made available for future down-hole measurement of thermal gradient, heat flow, ice chronology, and ice deformation. RAID will also sample for extremophile microorganisms. RAID is designed to penetrate up to 3,300 meters of ice and take sample cores in less than 200 hours. This rapid performance will allow completion of a borehole in about 10 days before moving to the next drilling site. RAID is unique because it can provide fast borehole access through thick ice; take short ice cores for paleoclimate study; sample the glacial bed to determine ice-flow conditions; take cores of subglacial bedrock for age dating and crustal history; and create boreholes for use as an observatory in the ice sheets. Together, the rapid drilling capability and mobility of the drilling system, along with ice-penetrating imaging methods, will provide a unique 3D picture of the interior Antarctic ice sheets.

In vivo biocompatibility of boron doped and nitrogen included conductive-diamond for use in medical implants.

PubMed

Garrett, David J; Saunders, Alexia L; McGowan, Ceara; Specks, Joscha; Ganesan, Kumaravelu; Meffin, Hamish; Williams, Richard A; Nayagam, David A X

2016-01-01

Recently, there has been interest in investigating diamond as a material for use in biomedical implants. Diamond can be rendered electrically conducting by doping with boron or nitrogen. This has led to inclusion of boron doped and nitrogen included diamond elements as electrodes and/or feedthroughs for medical implants. As these conductive device elements are not encapsulated, there is a need to establish their clinical safety for use in implants. This article compares the biocompatibility of electrically conducting boron doped diamond (BDD) and nitrogen included diamond films and electrically insulating poly crystalline diamond films against a silicone negative control and a BDD sample treated with stannous octoate as a positive control. Samples were surgically implanted into the back muscle of a guinea pig for a period of 4-15 weeks, excised and the implant site sectioned and submitted for histological analysis. All forms of diamond exhibited a similar or lower thickness of fibrotic tissue encapsulating compared to the silicone negative control samples. All forms of diamond exhibited similar or lower levels of acute, chronic inflammatory, and foreign body responses compared to the silicone negative control indicating that the materials are well tolerated in vivo. © 2015 Wiley Periodicals, Inc.

Fabrication of Hydrogenated Diamond Metal-Insulator-Semiconductor Field-Effect Transistors.

PubMed

Liu, Jiangwei; Koide, Yasuo

2017-01-01

Diamond is regarded as a promising material for fabrication of high-power and high-frequency electronic devices due to its remarkable intrinsic properties, such as wide band gap energy, high carrier mobility, and high breakdown field. Meanwhile, since diamond has good biocompatibility, long-term durability, good chemical inertness, and a large electron-chemical potential window, it is a suitable candidate for the fabrication of biosensors. Here, we demonstrate the fabrication of hydrogenated diamond (H-diamond) based metal-insulator-semiconductor field-effect transistors (MISFETs). The fabrication is based on the combination of laser lithography, dry-etching, atomic layer deposition (ALD), sputtering deposition (SD), electrode evaporation, and lift-off techniques. The gate insulator is high-k HfO 2 with a SD/ALD bilayer structure. The thin ALD-HfO 2 film (4.0 nm) acts as a buffer layer to prevent the hydrogen surface of the H-diamond from plasma discharge damage during the SD-HfO 2 deposition. The growth of H-diamond epitaxial layer, fabrication of H-diamond MISFETs, and electrical property measurements for the MISFETs is demonstrated. This chapter explains the fabrication of H-diamond FET based biosensors.

Single Crystal Diamond Needle as Point Electron Source.

PubMed

Kleshch, Victor I; Purcell, Stephen T; Obraztsov, Alexander N

2016-10-12

Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2-0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

Single Crystal Diamond Needle as Point Electron Source

NASA Astrophysics Data System (ADS)

Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

2016-10-01

Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2-0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

Field electron emission from diamond and related films synthesized by plasma enhanced chemical vapor deposition

NASA Astrophysics Data System (ADS)

Lu, Xianfeng

The focus of this thesis is the study of the field electron emission (FEE) of diamond and related films synthesized by plasma enhanced chemical vapor deposition. The diamond and related films with different morphologies and compositions were prepared in a microwave plasma-enhanced chemical vapor deposition (CVD) reactor and a hot filament CVD reactor. Various analytical techniques including scanning electron microscopy (SEM), atomic force microscopy (AFM), and Raman spectroscopy were employed to characterize the surface morphology and chemical composition. The influence of surface morphology on the field electron emission property of diamond films was studied. The emission current of well-oriented microcrystalline diamond films is relatively small compared to that of randomly oriented microcrystalline diamond films. Meanwhile, the nanocrystalline diamond film has demonstrated a larger emission current than microcrystalline diamond films. The nanocone structure significantly improves the electron emission current of diamond films due to its strong field enhancement effect. The sp2 phase concentration also has significant influence on the field electron emission property of diamond films. For the diamond films synthesized by gas mixture of hydrogen and methane, their field electron emission properties were enhanced with the increase of methane concentration. The field electron emission enhancement was attributed to the increase of sp2 phase concentration, which increases the electrical conductivity of diamond films. For the diamond films synthesized through graphite etching, the growth rate and nucleation density of diamond films increase significantly with decreasing hydrogen flow rate. The field electron emission properties of the diamond films were also enhanced with the decrease of hydrogen flow rate. The field electron emission enhancement can be also attributed to the increase of the sp 2 phase concentration. In addition, the deviation of the experimental Fowler-Nordheim (F-N) plot from a straight line was observed for graphitic nanocone films. The deviation can be mainly attributed to the nonuniform field enhancement factor of the graphitic nanocones. In low macroscopic electric field regions, electrons are emitted mainly from nanocone or nanocones with the largest field enhancement factor, which corresponds to the smallest slope magnitude. With the increase of electric field, nanocones with small field enhancement factors also contribute to the emission current, which results in a reduced average field enhancement factor and therefore a large slope magnitude.

76 FR 38459 - Proposed Collection; Comment Request for Rough Diamonds Reporting Requirements

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-30

... for Rough Diamonds Reporting Requirements AGENCY: Office of Foreign Assets Control, Treasury. ACTION... comments concerning OFAC's requirements to report information about the shipment of rough diamonds on an...: Request for Comments (Rough Diamonds Reporting) (202) 622-1657 Mail: Attn: Request for Comments (Rough...

Electrically conductive diamond electrodes

DOEpatents

Swain, Greg [East Lansing, MI; Fischer, Anne [Arlington, VA; Bennett, Jason [Lansing, MI; Lowe, Michael [Holt, MI

2009-05-19

An electrically conductive diamond electrode and process for preparation thereof is described. The electrode comprises diamond particles coated with electrically conductive doped diamond preferably by chemical vapor deposition which are held together with a binder. The electrodes are useful for oxidation reduction in gas, such as hydrogen generation by electrolysis.

21 CFR 872.4535 - Dental diamond instrument.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during the...

21 CFR 872.4535 - Dental diamond instrument.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during the...

21 CFR 872.4535 - Dental diamond instrument.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during the...

21 CFR 872.4535 - Dental diamond instrument.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during the...

21 CFR 872.4535 - Dental diamond instrument.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Dental diamond instrument. 872.4535 Section 872...) MEDICAL DEVICES DENTAL DEVICES Surgical Devices § 872.4535 Dental diamond instrument. (a) Identification. A dental diamond instrument is an abrasive device intended to smooth tooth surfaces during the...

Ultimate Atomic Bling: Nanotechnology of Diamonds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dahl, Jeremy

2010-05-25

Diamonds exist in all sizes, from the Hope Diamond to minuscule crystals only a few atoms across. The smallest of these diamonds are created naturally by the same processes that make petroleum. Recently, researchers discovered that these 'diamondoids' are formed in many different structural shapes, and that these shapes can be used like LEGO blocks for nanotechnology. This talk will discuss the discovery of these nano-size diamonds and highlight current SLAC/Stanford research into their applications in electronics and medicine.

Analysis of type IIb synthetic diamond using FTIR spectrometry

NASA Astrophysics Data System (ADS)

Klepikov, I. V.; Koliadin, A. V.; Vasilev, E. A.

2017-12-01

Analysis of internal structure in large IIb-type high pressure-high temperature (HPHT) synthetic single-crystal diamond are presented. The concentration of boron impurity in different growth sectors varies from 0.02 to 10.3 ppm. It is shown that in the manufacturing of synthetic diamond plates, internal inhomogeneities of the diamond should be taken into account; plates with different characteristics can be cut from one diamond, each of which can be used for its own purpose.

Monocrystalline CVD-diamond optics for high-power laser applications

NASA Astrophysics Data System (ADS)

Holly, C.; Traub, M.; Hoffmann, D.; Widmann, C.; Brink, D.; Nebel, C.; Gotthardt, T.; Sözbir, M. C.; Wenzel, C.

2016-03-01

The potential of diamond as an optical material for high-power laser applications in the wavelength regime from the visible spectrum (VIS) to the near infrared (NIR) is investigated. Single-crystal diamonds with lateral dimensions up to 7×7mm2 are grown with microwave plasma assisted chemical vapor deposition (MPACVD) in parallel with up to 60 substrates and are further processed to spherical optics for beam guidance and shaping. The synthetic diamonds offer superior thermal, mechanical and optical properties, including low birefringence, scattering and absorption, also around 1 μm wavelength. We present dielectric (AR and HR) coated single-crystal diamond optics which are tested under high laser power in the multi-kW regime. The thermally induced focal shift of the diamond substrates is compared to the focal shift of a standard collimating and focusing unit for laser cutting made of fused silica optics. Due to the high thermal conductivity and low absorption of the diamond substrates compared to the fused silica optics no additional focal shift caused by a thermally induced refractive index change in the diamond is observed in our experiments. We present experimental results regarding the performance of the diamond substrates with and without dielectric coatings under high power and the influences of growth induced birefringence on the optical quality. Finally, we discuss the potential of the presented diamond lenses for high-power applications in the field of laser materials processing.

Fabrication of Hierarchical Layer-by-Layer Assembled Diamond-based Core-Shell Nanocomposites as Highly Efficient Dye Absorbents for Wastewater Treatment

NASA Astrophysics Data System (ADS)

Zhao, Xinna; Ma, Kai; Jiao, Tifeng; Xing, Ruirui; Ma, Xilong; Hu, Jie; Huang, Hao; Zhang, Lexin; Yan, Xuehai

2017-03-01

The effective chemical modification and self-assembly of diamond-based hierarchical composite materials are of key importance for a broad range of diamond applications. Herein, we report the preparation of novel core-shell diamond-based nanocomposites for dye adsorption toward wastewater treatment through a layer-by-layer (LbL) assembled strategy. The synthesis of the reported composites began with the carboxyl functionalization of microdiamond by the chemical modification of diamond@graphene oxide composite through the oxidation of diamond@graphite. The carboxyl-terminated microdiamond was then alternatively immersed in the aqueous solution of amine-containing polyethylenimine and carboxyl-containing poly acrylic acid, which led to the formation of adsorption layer on diamond surface. Alternating (self-limiting) immersions in the solutions of the amine-containing and carboxyl-containing polymers were continued until the desired number of shell layers were formed around the microdiamond. The obtained core-shell nanocomposites were successfully synthesized and characterized by morphological and spectral techniques, demonstrating higher surface areas and mesoporous structures for good dye adsorption capacities than nonporous solid diamond particles. The LbL-assembled core-shell nanocomposites thus obtained demonstrated great adsorption capacity by using two model dyes as pollutants for wastewater treatment. Therefore, the present work on LbL-assembled diamond-based composites provides new alternatives for developing diamond hybrids as well as nanomaterials towards wastewater treatment applications.

Hydrogen Storage in Diamond Powder Utilizing Plasma NaF Surface Treatment for Fuel Cell Applications

NASA Astrophysics Data System (ADS)

Leal, David A.; Velez, Angel; Prelas, Mark A.; Gosh, Tushar; Leal-Quiros, E.

2006-12-01

Hydrogen Fuel Cells offer the vital solution to the world's socio-political dependence on oil. Due to existing difficulty in safe and efficient hydrogen storage for fuel cells, storing the hydrogen in hydrocarbon compounds such as artificial diamond is a realistic solution. By treating the surface of the diamond powder with a Sodium Fluoride plasma exposure, the surface of the diamond is cleaned of unwanted molecules. Due to fluorine's electro negativity, the diamond powder is activated and ready for hydrogen absorption. These diamond powder pellets are then placed on a graphite platform that is heated by conduction in a high voltage circuit made of tungsten wire. Then, the injection of hydrogen gas into chamber allows the storage of the Hydrogen on the surface of the diamond powder. By neutron bombardment in the nuclear reactor, or Prompt Gamma Neutron Activation Analysis, the samples are examined for parts per million amounts of hydrogen in the sample. Sodium Fluoride surface treatment allows for higher mass percentage of stored hydrogen in a reliable, resistant structure, such as diamond for fuel cells and permanently alters the diamonds terminal bonds for re-use in the effective storage of hydrogen. The highest stored amount utilizing the NaF plasma surface treatment was 22229 parts per million of hydrogen in the diamond powder which amounts to 2.2229% mass increase.

Improvements in the Formation of Boron-Doped Diamond Coatings on Platinum Wires Using the Novel Nucleation Process (NNP)

PubMed Central

Fhaner, Mathew; Zhao, Hong; Bian, Xiaochun; Galligan, James J.; Swain, Greg M.

2010-01-01

In order to increase the initial nucleation density for the growth of boron-doped diamond on platinum wires, we employed the novel nucleation process (NNP) originally developed by Rotter et al. and discussed by others [1–3]. This pretreatment method involves (i) the initial formation of a thin carbon layer over the substrate followed by (ii) ultrasonic seeding of this “soft” carbon layer with nanoscale particles of diamond. This two-step pretreatment is followed by the deposition of boron-doped diamond by microwave plasma-assisted CVD. Both the diamond seed particles and sites on the carbon layer itself function as the initial nucleation zones for diamond growth from an H2-rich source gas mixture. We report herein on the characterization of the pre-growth carbon layer formed on Pt as well as boron-doped films grown for 2, 4 and 6 h post NNP pretreatment. Results from scanning electron microscopy, Raman spectroscopy and electrochemical studies are reported. The NNP method increases the initial nucleation density on Pt and leads to the formation of a continuous diamond film in a shorter deposition time than is typical for wires pretreated by conventional ultrasonic seeding. The results indicate that the pregrowth layer itself consists of nanoscopic domains of diamond and functions well to enhance the initial nucleation of diamond without any diamond powder seeding. PMID:21617759

HD 93521, zeta Ophiuchi, and the effects of rapid rotation on the atmospheres and winds of 09.5 V stars

NASA Technical Reports Server (NTRS)

Massa, Derck

1995-01-01

Both low- and high-resolution IUE spectra of the rapidly rotating 09.5 V stars HD 93521 and zeta Oph are used to develop a coherent picture of the effects of rapid rotation on the atmospheres and winds of late, main-sequence O stars. The observational consequences are by far the strongest on HD 93521, most likely because it is being viewed nearly equator-on. In particular, it is shown that HD 93521 (1) a much smaller UV optical flux ratio than expected, (2) UV photospheric lines indicative of a BO supergiant, (3) an abnormally strong N v wind doublet, and (4) wind profiles suggesting that its wind has latitudinally dependent properties. Because HD 93521 has a larger observed v sin i than zeta Oph and yet its H-alpha emission is no stronger than in zeta Oph, it is speculated that zeta Oph actually rotates as fast or faster than HD 93521, but has a smaller sin i. Because zeta Oph is significantly reddened, nothing can be determined about its intrinsic UV energy distribution. However, it is shown that its UV photospheric lines are a bit peculiar and that its C IV and N V wind doublets are abnormally strong and have unusual profiles. The C IV profile agrees with models of a rotationally distorted wind similar to the one in HD 93521, except viewed at an angle i approximately 60 deg-80 deg. The spectral peculiarities of both stars are attributed to the combined effects of gravity darkening of their atmospheres and rotational distortion of their winds. The differences between their spectra are interpreted as the result of being viewed at different inclination angles. Because of the gravity darkening, atmospheric analyses of either star based on single temperature and surface gravity model atmospheres are probably unreliable. Finally, I describe how different effects conspire to make the spectroscopic signatures of gravity darkening so pronounced at 09.5 V.

Plasma spraying method for forming diamond and diamond-like coatings

DOEpatents

Holcombe, C.E.; Seals, R.D.; Price, R.E.

1997-06-03

A method and composition is disclosed for the deposition of a thick layer of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate. The softened or molten composition crystallizes on the substrate to form a thick deposition layer comprising at least a diamond or diamond-like material. The selected composition includes at least glassy carbon as a primary constituent and may include at least one secondary constituent. Preferably, the secondary constituents are selected from the group consisting of at least diamond powder, boron carbide (B{sub 4}C) powder and mixtures thereof. 9 figs.

Thick homoepitaxial (110)-oriented phosphorus-doped n-type diamond

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balasubramaniam, Y.; Pobedinskas, P., E-mail: paulius.pobedinskas@uhasselt.be; Janssens, S. D.

2016-08-08

The fabrication of n-type diamond is essential for the realization of electronic components for extreme environments. We report on the growth of a 66 μm thick homoepitaxial phosphorus-doped diamond on a (110)-oriented diamond substrate, grown at a very high deposition rate of 33 μm h{sup −1}. A pristine diamond lattice is observed by high resolution transmission electron microscopy, which indicates the growth of high quality diamond. About 2.9 × 10{sup 16} cm{sup −3} phosphorus atoms are electrically active as substitutional donors, which is 60% of all incorporated dopant atoms. These results indicate that P-doped (110)-oriented diamond films deposited at high growth rates are promising candidates formore » future use in high-power electronic applications.« less

Morphological Features of Diamond Crystals Dissolved in Fe0.7S0.3 Melt at 4 GPa and 1400°C

NASA Astrophysics Data System (ADS)

Sonin, V. M.; Zhimulev, E. I.; Pomazanskiy, B. S.; Zemnuhov, A. L.; Chepurov, A. A.; Afanasiev, V. P.; Chepurov, A. I.

2018-01-01

An experimental study of the dissolution of natural and synthetic diamonds in a sulfur-bearing iron melt (Fe0.7S0.3) with high P-T parameters (4 GPa, 1400°C) was performed. The results demonstrated that under these conditions, octahedral crystals with flat faces and rounded tetrahexahedral diamond crystals are transformed into rounded octahedroids, which have morphological characteristics similar to those of natural diamonds from kimberlite. It was suggested that, taking into account the complex history of individual natural diamond crystals, including the dissolution stages, sulfur-bearing metal melts up to sulfide melts were not only diamond-forming media during the early evolution of the Earth, but also natural solvents of diamond in the mantle environment before the formation of kimberlitic melts.

Drilling resistance: A method to investigate bone quality.

PubMed

Lughmani, Waqas A; Farukh, Farukh; Bouazza-Marouf, Kaddour; Ali, Hassan

2017-01-01

Bone drilling is a major part of orthopaedic surgery performed during the internal fixation of fractured bones. At present, information related to drilling force, drilling torque, rate of drill-bit penetration and drill-bit rotational speed is not available to orthopaedic surgeons, clinicians and researchers as bone drilling is performed manually. This study demonstrates that bone drilling force data if recorded in-vivo, during the repair of bone fractures, can provide information about the quality of the bone. To understand the variability and anisotropic behaviour of cortical bone tissue, specimens cut from three anatomic positions of pig and bovine were investigated at the same drilling speed and feed rate. The experimental results showed that the drilling force does not only vary from one animal bone to another, but also vary within the same bone due to its changing microstructure. Drilling force does not give a direct indication of bone quality; therefore it has been correlated with screw pull-out force to provide a realistic estimation of the bone quality. A significantly high value of correlation (r2 = 0.93 for pig bones and r2 = 0.88 for bovine bones) between maximum drilling force and normalised screw pull-out strength was found. The results show that drilling data can be used to indicate bone quality during orthopaedic surgery.

Noise Estimation and Adaptive Encoding for Asymmetric Quantum Error Correcting Codes

NASA Astrophysics Data System (ADS)

Florjanczyk, Jan; Brun, Todd; CenterQuantum Information Science; Technology Team

We present a technique that improves the performance of asymmetric quantum error correcting codes in the presence of biased qubit noise channels. Our study is motivated by considering what useful information can be learned from the statistics of syndrome measurements in stabilizer quantum error correcting codes (QECC). We consider the case of a qubit dephasing channel where the dephasing axis is unknown and time-varying. We are able to estimate the dephasing angle from the statistics of the standard syndrome measurements used in stabilizer QECC's. We use this estimate to rotate the computational basis of the code in such a way that the most likely type of error is covered by the highest distance of the asymmetric code. In particular, we use the [ [ 15 , 1 , 3 ] ] shortened Reed-Muller code which can correct one phase-flip error but up to three bit-flip errors. In our simulations, we tune the computational basis to match the estimated dephasing axis which in turn leads to a decrease in the probability of a phase-flip error. With a sufficiently accurate estimate of the dephasing axis, our memory's effective error is dominated by the much lower probability of four bit-flips. Aro MURI Grant No. W911NF-11-1-0268.