Fascinating Magnetic Energy Storage Nanomaterials: A Brief Review.

PubMed

Sreenivasulu, Kummari V; Srikanth, Vadali V S S

2017-07-10

In this brief review, the importance of nanotechnology in developing novel magnetic energy storage materials is discussed. The discussion covers recent patents on permanent magnetic materials and especially covers processing of permanent magnets (rare-earth and rare-earth free magnets), importance of rare-earth permanent magnets and necessity of rare-earth free permanent magnets. Magnetic energy storage materials are those magnetic materials which exhibit very high energy product (BH)max (where B is the magnetic induction in Gauss (G) whereas H is the applied magnetic field in Oersted (Oe)). (BH)max is the direct measure of the ability of a magnetic material to store energy. In this context, processing of magnetic energy storage composite materials constituted by soft and hard magnetic materials played a predominant role in achieving high (BH)max values due to the exchange coupling phenomenon between the soft and hard magnetic phases within the composite. Magnetic energy storage composites are normally composed of rare-earth magnetic materials as well as rare-earth free magnetic materials. Nanotechnology's influence on the enhancement of energy product due to the exchange coupling phenomenon is of great prominence and therefore discussed in this review. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A study of the suitability of ferrite for use in low-field insertion devices

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

Johnson, K.; Hassenzahl, W.V.

1995-02-01

Most insertion devices built to date use rare-earth permanent-magnet materials, which have a high remanent field and are more expensive than many other permanent-magnet materials. Low-field insertion devices could use less-expensive, lower performance magnetic materials if they had suitable magnetic characteristics. These materials must be resistant to demagnetization during construction and operation of the insertion device, have uniform magnetization, possess low minor-axis magnetic moments, and have small minor field components on the surfaces. This paper describes an investigation to determine if ferrite possesses magnetic qualities suitable for insertion device applications. The type of ferrite investigated, MMPA Ceramic 8 from Stackpolemore » Inc., was found to be acceptable for insertion device applications.« less

Electric vehicle traction motors - The development of an advanced motor concept

NASA Technical Reports Server (NTRS)

Campbell, P.

1980-01-01

An axial-field permanent magnet traction motor is described, similar to several advanced motors that are being developed in the United States. This type of machine has several advantages over conventional dc motors, particularly in the electric vehicle application. The rapidly changing cost of magnetic materials, particularly cobalt, makes it important to study the utilization of permanent magnet materials in such machines. The impact of different magnets on machine design is evaluated, and the advantages of using iron powder composites in the armature are assessed.

Occlusal glass ionomer cermet, resin sandwich and amalgam restorations: a 2-year clinical study.

PubMed

Lidums, A; Wilkie, R; Smales, R

1993-08-01

This study compared the clinical behavior of a glass ionomer silver cermet (Ketac-Silver), a posterior resin composite (Visio-Molar) used with the "sandwich" technique, and a high-copper amalgam (Dispersalloy) for restoring conventional Class I occlusal cavity preparations. Two dentists placed 116 restorations in the posterior permanent teeth of 35 adults treated at a dental hospital. Restorations were assessed at 6-month intervals over 2 years for bulk loss of material and occlusal wear, surface voids, roughness and cracking, surface and marginal staining, and marginal fracture. Losses of material and surface voids were obvious with the cermet material, with surface crazing or cracking being present in 33% of the restorations. The cermet cannot be recommended as a long-term permanent restorative material if the restorations are likely to be subjected to heavy occlusal stresses and abrasive wear.

X-ray Sensitive Material

DTIC Science & Technology

2015-12-01

The research resulted in a composite material that holds a quasi-permanent electric charge and rapidly discharges the electric charge upon X-ray...quasi-permanent electric charge and rapidly discharge the electric charge upon X-ray exposure. The composite material combined the properties of an...9 7. Schematic of Circuit for Recording Sample’s Capacitor Discharge ............... 12 8. Schematic of Circuit for

Effects of zinc oxide-eugenol and calcium hydroxide/ iodoform on delaying root resorption in primary molars without successors.

PubMed

Lin, Bichen; Zhao, Yuming; Yang, Jie; Wang, Wenjun; Ge, Li-hong

2014-01-01

The purpose of this study was to compare the effects of zinc oxide-eugenol (ZOE) and calcium hydroxide/iodoform paste (Vitapex), as root canal filling materials in pulpectomy, on delaying the root resorption of primary molars without permanent successors. Animal models without permanent successors were surgically established in beagle dogs. Root resorption was observed via periapical radiographs. The onset of root resorption of primary mandibular molars without successors occurred later (p<0.05) than physiologic resorption. ZOE pulpectomy clearly delayed the root resorption of primary molars without permanent successors (p<0.05), whereas resorption of primary molars with Vitapex pulpectomy started at almost the same time as physiologic resorption. Compared with Vitapex, ZOE was a more effective root canal filling material in delaying the root resorption of primary molars.

The use of pure carbon for permanent percutaneous electrical connector systems

NASA Technical Reports Server (NTRS)

Mooney, V.; Hartmann, D. B.; Mcneal, D.; Benson, J.

1973-01-01

Pure carbon was used as an electrode in the clinical application of long-term neuromuscular stimulation, as well as a connector for permanent neuroelectrodes. The history of this material and some examples of the material in use are presented.

Does Timing of Eruption in First Primary Tooth Correlate with that of First Permanent Tooth? A 9-years Cohort Study

PubMed Central

Poureslami, Hamidreza; Asl Aminabadi, Naser; Sighari Deljavan, Alireza; Erfanparast, Leila; Sohrabi, Azin; Jamali, Zahra; Ghertasi Oskouei, Sina; Hazem, Kameliya; Shirazi, Sajjad

2015-01-01

Background and aims. Predicting the teeth eruption time is a valuable tool in pediatric dentistry since it can affects scheduling dental and orthodontic treatments. This study investigated the relationship between the eruption time of first primary and permanent teeth and the variation in the eruption time considering socioeconomic status (SES) in a 9-year population- based cohort study. Materials and methods. 307 subjects were examined at bimonthly intervals during the first and second years of life and then at six-month intervals until the eruption of first permanent tooth. Eruption times of primary and permanent tooth were recorded for each child. A modified form of Kuppuswamy’s scale was used to assess the SES. Results. Among 267 subjects completed all follow-ups, the eruption time for first primary and permanent teeth indicated a direct strong correlation; in that one month delayed or early eruption of firstprimary tooth resulted in 4.21 months delayed or early eruption of first appearing permanent tooth (r = 0.91, n = 267, P <0.001). No significant correlation was observed between the eruption time of first primary and first permanent teeth and SES (P = 0.67, P = 0.75, respectively). Conclusion. The eruption timing for the first primary tooth had a correlation with the first permanent tooth eruption tim-ing, while SES did not have any influence on eruption times. PMID:26236432

49 CFR 173.302a - Additional requirements for shipment of nonliquefied (permanent) compressed gases in...

Code of Federal Regulations, 2010 CFR

2010-10-01

... nonliquefied (permanent) compressed gases in specification cylinders. 173.302a Section 173.302a Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SHIPPERS-GENERAL REQUIREMENTS FOR SHIPMENTS AND...

3D-Printed Permanent Magnets Outperform Conventional Versions, Conserve Rare Materials

ScienceCinema

Paranthaman, Parans

2018-06-13

Researchers at the Department of Energy’s Oak Ridge National Laboratory have demonstrated that permanent magnets produced by additive manufacturing can outperform bonded magnets made using traditional techniques while conserving critical materials. The project is part of DOE’s Critical Materials Institute (CMI), which seeks ways to eliminate and reduce reliance on rare earth metals and other materials critical to the success of clean energy technologies.

Testing of the permanent magnet material Mn-Al-C for potential use in propulsion motors for electric vehicles

NASA Technical Reports Server (NTRS)

Abdelnour, Z.; Mildrun, H.; Strant, K.

1981-01-01

The development of Mn-Al-C permanent magnets is reviewed. The general properties of the material are discussed and put into perspective relative to alnicos and ferrites. The traction motor designer's demands of a permanent magnet for potential use in electric vehicle drives are reviewed. Tests determined magnetic design data and mechanical strength properties. Easy axis hysteresis and demagnetization curves, recoil loops and other minor loop fields were measured over a temperature range from -50 to 150 C. Hysteresis loops were also measured for three orthogonal directions (the one easy and two hard axes of magnetization). Extruded rods of three different diameters were tested. The nonuniformity of properties over the cross section of the 31 mm diameter rod was studied. Mechanical compressive and bending strength at room temperature was determined on individual samples from the 31 mm rod.

Characterization Tests for Mineral Fillers Related to Performance of Asphalt Paving Mixtures

DOT National Transportation Integrated Search

1988-01-01

Various studies have shown that the properties of mineral filler, especially the material passing 0.075 mm (No. 200) sieve (generally called P200 material), have a significant effect on the performance of asphalt paving mixtures in terms of permanent...

Dynamic high pressure process for fabricating superconducting and permanent magnetic materials

DOEpatents

Nellis, William J.; Geballe, Theodore H.; Maple, M. Brian

1990-01-01

Shock wave formation of thin layers of materials with improved superconducting and permanent magnetic properties and improved microstructures. The material fabrication system includes a sandwiched structure including a powder material placed between two solid members to enable explosive shock consolidation. The two solid members are precooled to about 80.degree.-100.degree. K. to reduce the residual temperatures attained as a result of the shock wave treatment, and thereby increase the quench rate of the consolidated powder.

Dynamic high pressure process for fabricating superconducting and permanent magnetic materials

DOEpatents

Nellis, W.J.; Geballe, T.H.; Maple, M.B.

1990-03-13

Shock wave formation of thin layers of materials with improved superconducting and permanent magnetic properties and improved microstructures is disclosed. The material fabrication system includes a sandwiched structure including a powder material placed between two solid members to enable explosive shock consolidation. The two solid members are precooled to about 80--100 K to reduce the residual temperatures attained as a result of the shock wave treatment, and thereby increase the quench rate of the consolidated powder. 9 figs.

Science and Technology of Nanostructured Magnetic Materials

DTIC Science & Technology

1990-07-06

galvano-magnetic and magneto-optic effects that can lead to future storage technologies. Ultrafine particles also show interesting and unique properties...areas including thin films, multilayers, disordered systems, ultrafine particles , intermetallic compounds, permanent magnets and magnetic imaging... ultrafine particles , intermetallic compounds, permanent magnets and magnetic imaging techniques. The development of new techniques for materials preparation

Topology optimization of reduced rare-earth permanent magnet arrays with finite coercivity

NASA Astrophysics Data System (ADS)

Teyber, R.; Trevizoli, P. V.; Christiaanse, T. V.; Govindappa, P.; Rowe, A.

2018-05-01

The supply chain risk of rare-earth permanent magnets has yielded research efforts to improve both materials and magnetic circuits. While a number of magnet optimization techniques exist, literature has not incorporated the permanent magnet failure process stemming from finite coercivity. To address this, a mixed-integer topology optimization is formulated to maximize the flux density of a segmented Halbach cylinder while avoiding permanent demagnetization. The numerical framework is used to assess the efficacy of low-cost (rare-earth-free ferrite C9), medium-cost (rare-earth-free MnBi), and higher-cost (Dy-free NdFeB) permanent magnet materials. Novel magnet designs are generated that produce flux densities 70% greater than the segmented Halbach array, albeit with increased magnet mass. Three optimization formulations are then explored using ferrite C9 that demonstrates the trade-off between manufacturability and design sophistication, generating flux densities in the range of 0.366-0.483 T.

Permanent magnet motors

NASA Astrophysics Data System (ADS)

Richter, E.

1984-09-01

The work deals with the design and analysis study for the conceptual design of an economical high efficiency ac motor based on permanent magnets. The design and trade off studies have covered the material considerations, the design tradeoff options as well as transient and steady state performance considerations, and other options. The baseline comparison is the high efficiency induction motor. The permanent magnet (PM) motor must fit into the same frame size and surpass the induction motor on a life cost basis that includes 2.5 years of operation at a 50% duty cycle. It is shown that a motor based upon ferrite magnets does meet the objectives of the program in ratings of up to 25 hp. A 7.5 motor design is carried through the conceptual design stage.

Permanent Magnet Ecr Plasma Source With Magnetic Field Optimization

DOEpatents

Doughty, Frank C.; Spencer, John E.

2000-12-19

In a plasma-producing device, an optimized magnet field for electron cyclotron resonance plasma generation is provided by a shaped pole piece. The shaped pole piece adjusts spacing between the magnet and the resonance zone, creates a convex or concave resonance zone, and decreases stray fields between the resonance zone and the workpiece. For a cylindrical permanent magnet, the pole piece includes a disk adjacent the magnet together with an annular cylindrical sidewall structure axially aligned with the magnet and extending from the base around the permanent magnet. The pole piece directs magnetic field lines into the resonance zone, moving the resonance zone further from the face of the magnet. Additional permanent magnets or magnet arrays may be utilized to control field contours on a local scale. Rather than a permeable material, the sidewall structure may be composed of an annular cylindrical magnetic material having a polarity opposite that of the permanent magnet, creating convex regions in the resonance zone. An annular disk-shaped recurve section at the end of the sidewall structure forms magnetic mirrors keeping the plasma off the pole piece. A recurve section composed of magnetic material having a radial polarity forms convex regions and/or magnetic mirrors within the resonance zone.

Development of a low-cost double rotor axial flux motor with soft magnetic composite and ferrite permanent magnet materials

NASA Astrophysics Data System (ADS)

Liu, Chengcheng; Zhu, Jianguo; Wang, Youhua; Guo, Youguang; Lei, Gang; Liu, Xiaojing

2015-05-01

This paper proposes a low-cost double rotor axial flux motor (DRAFM) with low cost soft magnetic composite (SMC) core and ferrite permanent magnets (PMs). The topology and operating principle of DRAFM and design considerations for best use of magnetic materials are presented. A 905 W 4800 rpm DRAFM is designed for replacing the high cost NdFeB permanent magnet synchronous motor (PMSM) in a refrigerator compressor. By using the finite element method, the electromagnetic parameters and performance of the DRAFM operated under the field oriented control scheme are calculated. Through the analysis, it is shown that that the SMC and ferrite PM materials can be good candidates for low-cost electric motor applications.

Comparative Assessment of Conventional Composites and Coloured Compomers in Permanent Molars of Children with Mixed Dentition: A Pilot Study

PubMed Central

Kohli, Divyata; Badakar, Chandrashekhar M; Vyavahare, Supriya S; Shah, Parin P; Gokhale, Niraj S; Patel, Punit M; Mundada, Madhura V

2017-01-01

Introduction Early treatment of carious lesions in children is important for the maintenance of oral health. Multicoloured restorations could be the impetus for an extremely nervous or defiant child to take dental treatment. Aim The aim of this study was to assess and compare the clinical success of conventional composites and coloured compomer material in first permanent molars of children with mixed dentition. Materials and Methods A total of sixty sites, divided into two groups, with thirty subjects in each group using split mouth design were chosen amongst patients reporting to Department of Pedodontics and Preventive Dentistry. In control group conventional composites were placed, similarly coloured compomers were placed in experimental group under standard operating protocol. Patients were recalled for assessment of clinical success amongst control as well as experimental group at regular intervals of one; three and six months follow up based on Modified Ryge’s Criteria. Statistical analysis was done using Chi-square test using SPSS version 20.0 (Chicago, USA). Results Both conventional composites and coloured compomers had comparable retention rates in terms of anatomical form, marginal integrity, secondary caries and marginal discolouration. Conclusion The coloured compomer material showed promising results in this six month follow up study in permanent molars and had properties comparable to that of conventional composites. PMID:28764297

Adhesive coated electrical apparatus having sublimable protective covering and an assembly method

DOEpatents

Wootton, Roy E.

1982-01-01

Electrical apparatus including an enclosure, an electrode disposed within the enclosure, and supports for insulatably supporting the electrode within the enclosure has a permanently sticky adhesive material which is disposed on the interior surface of the outer enclosure. A high-vapor-pressure sublimable material is disposed on the permanently sticky adhesive material, with the sublimable material capable of subliming away in the presence of a vacuum. The presence of the sublimable material enables the apparatus to be non-sticky during assembly and handling operations, while being rendered sticky upon commissioning of the apparatus.

Color Stability of Silicone or Acrylic Denture Liners: An in Vitro Investigation

PubMed Central

Ergun, Gulfem; Nagas, Isil Cekic

2007-01-01

Objectives The aim of this study was to compare the color stability of three acrylic based hard liners (Ufi gel hard, Dura-Liner II, Tokuso Rebase) and two silicone based soft liners (Ufi gel permanent, Molloplast B) by using the colorimeter. Methods Sixty disc-shaped samples, with uniform size of 10 mm diameter and 2 mm in thickness were fabricated for each material. Thirty samples were made as control group in distilled water and the remaining thirty samples were weathered in accelerated aging chamber. Color measurements were made before and after distilled water and aging. Data were statistically analyzed using nonparametric Kruskal-Wallis and Mann-Whitney U tests. Results Data showed that there are significant differences among materials in both after distilled water and aging treatments (P<.001). These results indicated that the most discolored liner material was Dura Liner II after aging (ΔE*=16.30) and the least discolored material was Ufi gel permanent after distilled water (ΔE*=0.41). Conclusions Based on the results of this study, silicone based liner materials are considered to be more color stable than acrylic based liner materials. PMID:19212558

Characteristics Buton Natural Asphalt-Rubber (BNA-R) on the Performance Improvement of Warm Mix Asphalt Using Natural Zeolite

NASA Astrophysics Data System (ADS)

Wahjuningsih, Nurul; Pranowo Hadiwardoyo, Sigit; Jachrizal Sumabrata, R.

2018-03-01

The decrease in the ability of service of pavement can be caused by the durability factor in the pavement layer in receiving heavy traffic load and the temperature of the pavement. Permanent deformation is one of the criteria of failure of asphalt mixture. Performance assessment of the asphalt mixture can be observed from the rheological properties of asphalt binder. The use of BNA-R in this study is intended to modify the characteristics of bitumen penetration grade 60 / 70 used in warm mix asphalt. Warm mix asphalt with lower temperatures of mixing and compaction than conventional asphalt mixtures was chosen because it is more environmentally friendly. To reduce the temperature in this warm asphalt technology is achieved by using natural zeolite. Both of these materials are local materials that are widely available in Indonesia. The rheology of asphalt 60/70 modified with BNA-R indicates that the addition of BNA-R in the base asphalt increase the complex modulus value and decrease the phase angle value. These values were related to the performance of mixture in the permanent deformation criteria. Reducing the temperature of mixing and compaction should be balanced with modifying the asphalt binder used. Rutting due to permanent deformation can resulted in inconvenience to the passengers and can lead to high costs of road maintenance. To determine the permanent deformation of asphalt mix with material combinations was performed through the wheel tracking test machine with 3,780 cycles for 3 hours. The results shows that after test track over 7 thousand passes have seen permanent deformation characteristics of asphalt concrete mixture with a variation of the characteristics of bitumen.

A comparative study of zirconium and titanium implants in rat: osseointegration and bone material quality.

PubMed

Hoerth, Rebecca M; Katunar, María R; Gomez Sanchez, Andrea; Orellano, Juan C; Ceré, Silvia M; Wagermaier, Wolfgang; Ballarre, Josefina

2014-02-01

Permanent metal implants are widely used in human medical treatments and orthopedics, for example as hip joint replacements. They are commonly made of titanium alloys and beyond the optimization of this established material, it is also essential to explore alternative implant materials in view of improved osseointegration. The aim of our study was to characterize the implant performance of zirconium in comparison to titanium implants. Zirconium implants have been characterized in a previous study concerning material properties and surface characteristics in vitro, such as oxide layer thickness and surface roughness. In the present study, we compare bone material quality around zirconium and titanium implants in terms of osseointegration and therefore characterized bone material properties in a rat model using a multi-method approach. We used light and electron microscopy, micro Raman spectroscopy, micro X-ray fluorescence and X-ray scattering techniques to investigate the osseointegration in terms of compositional and structural properties of the newly formed bone. Regarding the mineralization level, the mineral composition, and the alignment and order of the mineral particles, our results show that the maturity of the newly formed bone after 8 weeks of implantation is already very high. In conclusion, the bone material quality obtained for zirconium implants is at least as good as for titanium. It seems that the zirconium implants can be a good candidate for using as permanent metal prosthesis for orthopedic treatments.

Design and simulation of permanent magnet synchronous motor control system

NASA Astrophysics Data System (ADS)

Li, Li; Liu, Yongqiu

2018-06-01

In recent years, with the development of power electronics, microelectronics, new motor control theory and rare earth permanent magnet materials, permanent magnet synchronous motors have been rapidly applied. Permanent magnet synchronous motors have the advantages of small size, low loss and high efficiency. Today, energy conservation and environmental protection are increasingly valued. It is very necessary to study them. Permanent magnet synchronous motor control system has a wide range of application prospects in the fields of electric vehicles, ships and other transportation. Using the simulation function of MATLAB/SIMULINK, a modular design structure was used to simulate the whole system model of speed loop adjustment, current PI modulation, SVPWM (Space Vector Pulse Width Module) wave generation and double closed loop. The results show that this control method has good robustness, and this method can improve the design efficiency and shorten the system design time. In this article, the analysis of the control principle of modern permanent magnet synchronous motor and the various processes of MATLAB simulation application will be analyzed in detail. The basic theory, basic method and application technology of the permanent magnet synchronous motor control system are systematically introduced.

Rare-Earth-Free Permanent Magnets for Electrical Vehicle Motors and Wind Turbine Generators: Hexagonal Symmetry Based Materials Systems Mn-Bi and M-type Hexaferrite

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

Hong, Yang-Ki; Haskew, Timothy; Myryasov, Oleg

2014-06-05

The research we conducted focuses on the rare-earth (RE)-free permanent magnet by modeling, simulating, and synthesizing exchange coupled two-phase (hard/soft) RE-free core-shell nano-structured magnet. The RE-free magnets are made of magnetically hard core materials (high anisotropy materials including Mn-Bi-X and M-type hexaferrite) coated by soft shell materials (high magnetization materials including Fe-Co or Co). Therefore, our research helps understand the exchange coupling conditions of the core/shell magnets, interface exchange behavior between core and shell materials, formation mechanism of core/shell structures, stability conditions of core and shell materials, etc.

Finite element analysis of gradient z-coil induced eddy currents in a permanent MRI magnet.

PubMed

Li, Xia; Xia, Ling; Chen, Wufan; Liu, Feng; Crozier, Stuart; Xie, Dexin

2011-01-01

In permanent magnetic resonance imaging (MRI) systems, pulsed gradient fields induce strong eddy currents in the conducting structures of the magnet body. The gradient field for image encoding is perturbed by these eddy currents leading to MR image distortions. This paper presents a comprehensive finite element (FE) analysis of the eddy current generation in the magnet conductors. In the proposed FE model, the hysteretic characteristics of ferromagnetic materials are considered and a scalar Preisach hysteresis model is employed. The developed FE model was applied to study gradient z-coil induced eddy currents in a 0.5 T permanent MRI device. The simulation results demonstrate that the approach could be effectively used to investigate eddy current problems involving ferromagnetic materials. With the knowledge gained from this eddy current model, our next step is to design a passive magnet structure and active gradient coils to reduce the eddy current effects. Copyright © 2010 Elsevier Inc. All rights reserved.

Perspectives on Permanent Magnetic Materials for Energy Conversion and Power Generation

NASA Astrophysics Data System (ADS)

Lewis, Laura H.; Jiménez-Villacorta, Félix

2013-01-01

Permanent magnet development has historically been driven by the need to supply larger magnetic energy in ever smaller volumes for incorporation in an enormous variety of applications that include consumer products, transportation components, military hardware, and clean energy technologies such as wind turbine generators and hybrid vehicle regenerative motors. Since the 1960s, the so-called rare-earth "supermagnets," composed of iron, cobalt, and rare-earth elements such as Nd, Pr, and Sm, have accounted for the majority of global sales of high-energy-product permanent magnets for advanced applications. In rare-earth magnets, the transition-metal components provide high magnetization, and the rare-earth components contribute a very large magnetocrystalline anisotropy that donates high resistance to demagnetization. However, at the end of 2009, geopolitical influences created a worldwide strategic shortage of rare-earth elements that may be addressed, among other actions, through the development of rare-earth-free magnetic materials harnessing sources of magnetic anisotropy other than that provided by the rare-earth components. Materials engineering at the micron scale, nanoscale, and Angstrom scales, accompanied by improvements in the understanding and characterization of nanoscale magnetic phenomena, is anticipated to result in new types of permanent magnetic materials with superior performance.

Effects of Infographics on Students Achievement and Attitude towards Geography Lessons

ERIC Educational Resources Information Center

Çifçi, Taner

2016-01-01

Geography is a very comprehensive field of study with many subjects to study topics. Using a wide range of materials in the teaching of this course can this lesson be made effective and permanent because we do not have chances to observe natural phenomena. Therefore, in geography education materials natural environment is to be brought to class by…

Rotatable Small Permanent Magnet Array for Ultra-Low Field Nuclear Magnetic Resonance Instrumentation: A Concept Study

PubMed Central

Vegh, Viktor; Reutens, David C.

2016-01-01

Object We studied the feasibility of generating the variable magnetic fields required for ultra-low field nuclear magnetic resonance relaxometry with dynamically adjustable permanent magnets. Our motivation was to substitute traditional electromagnets by distributed permanent magnets, increasing system portability. Materials and Methods The finite element method (COMSOL®) was employed for the numerical study of a small permanent magnet array to calculate achievable magnetic field strength, homogeneity, switching time and magnetic forces. A manually operated prototype was simulated and constructed to validate the numerical approach and to verify the generated magnetic field. Results A concentric small permanent magnet array can be used to generate strong sample pre-polarisation and variable measurement fields for ultra-low field relaxometry via simple prescribed magnet rotations. Using the array, it is possible to achieve a pre-polarisation field strength above 100 mT and variable measurement fields ranging from 20–50 μT with 200 ppm absolute field homogeneity within a field-of-view of 5 x 5 x 5 cubic centimetres. Conclusions A dynamic small permanent magnet array can generate multiple highly homogeneous magnetic fields required in ultra-low field nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) instruments. This design can significantly reduce the volume and energy requirements of traditional systems based on electromagnets, improving portability considerably. PMID:27271886

40 CFR 60.536 - Permanent label, temporary label, and owner's manual.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Performance for New Residential Wood Heaters § 60.536 Permanent label, temporary label, and owner's manual. (a... section. (2) Except for wood heaters subject to § 60.530 (e), (f), or (g), the permanent label shall... material expected to last the lifetime of the wood heater, (iv) Present required information in a manner so...

40 CFR 60.536 - Permanent label, temporary label, and owner's manual.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Performance for New Residential Wood Heaters § 60.536 Permanent label, temporary label, and owner's manual. (a... section. (2) Except for wood heaters subject to § 60.530 (e), (f), or (g), the permanent label shall... material expected to last the lifetime of the wood heater, (iv) Present required information in a manner so...

40 CFR 60.536 - Permanent label, temporary label, and owner's manual.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Performance for New Residential Wood Heaters § 60.536 Permanent label, temporary label, and owner's manual. (a... section. (2) Except for wood heaters subject to § 60.530 (e), (f), or (g), the permanent label shall... material expected to last the lifetime of the wood heater, (iv) Present required information in a manner so...

40 CFR 280.71 - Permanent closure and changes-in-service.

Code of Federal Regulations, 2011 CFR

2011-07-01

... UNDERGROUND STORAGE TANKS (UST) Out-of-Service UST Systems and Closure § 280.71 Permanent closure and changes... sludges. All tanks taken out of service permanently must also be either removed from the ground or filled with an inert solid material. (c) Continued use of an UST system to store a non-regulated substance is...

40 CFR 280.71 - Permanent closure and changes-in-service.

Code of Federal Regulations, 2013 CFR

2013-07-01

... UNDERGROUND STORAGE TANKS (UST) Out-of-Service UST Systems and Closure § 280.71 Permanent closure and changes... sludges. All tanks taken out of service permanently must also be either removed from the ground or filled with an inert solid material. (c) Continued use of an UST system to store a non-regulated substance is...

40 CFR 280.71 - Permanent closure and changes-in-service.

Code of Federal Regulations, 2012 CFR

2012-07-01

... UNDERGROUND STORAGE TANKS (UST) Out-of-Service UST Systems and Closure § 280.71 Permanent closure and changes... sludges. All tanks taken out of service permanently must also be either removed from the ground or filled with an inert solid material. (c) Continued use of an UST system to store a non-regulated substance is...

40 CFR 280.71 - Permanent closure and changes-in-service.

Code of Federal Regulations, 2014 CFR

2014-07-01

... UNDERGROUND STORAGE TANKS (UST) Out-of-Service UST Systems and Closure § 280.71 Permanent closure and changes... sludges. All tanks taken out of service permanently must also be either removed from the ground or filled with an inert solid material. (c) Continued use of an UST system to store a non-regulated substance is...

40 CFR 60.536 - Permanent label, temporary label, and owner's manual.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Performance for New Residential Wood Heaters § 60.536 Permanent label, temporary label, and owner's manual. (a... section. (2) Except for wood heaters subject to § 60.530 (e), (f), or (g), the permanent label shall... material expected to last the lifetime of the wood heater, (iv) Present required information in a manner so...

40 CFR 60.536 - Permanent label, temporary label, and owner's manual.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Performance for New Residential Wood Heaters § 60.536 Permanent label, temporary label, and owner's manual. (a... section. (2) Except for wood heaters subject to § 60.530 (e), (f), or (g), the permanent label shall... material expected to last the lifetime of the wood heater, (iv) Present required information in a manner so...

Variation of mechanical properties due to hygrothermal ageing and permanent changes upon redrying in clay/epoxy nanocomposites

NASA Astrophysics Data System (ADS)

Hamim, Salah Uddin Ahmed

2011-12-01

Epoxy polymers are an important class of material for use in various applications. Due to their hydrophilic nature, epoxy resins tend to absorb moisture. Absorption of moisture degrades the functional, structural and mechanical properties. For polymers, moisture absorption can lead to both reversible and irreversible changes. In this study, the combined effect of moisture and elevated temperature on the mechanical properties of Epon 862 and its nanocomposites were investigated. The extent of permanent damage on fracture toughness and flexural properties of epoxy, due to the aggressive degradation provided by hygrothermal ageing, was determined by drying the epoxy and their clay/epoxy nanocomposites after moisture absorption. From the investigation it was found out that, clay can help in reducing the negative effect of hygrothermal ageing. Significant permanent damage was observed for fracture toughness and modulus, while the extent of permanent damage was less significant for flexural strength. Failure mechanism of this nanocomposites were studied by using Scanning Electron Microscopy (SEM).

Radial stiffness improvement of a flywheel system using multi-surface superconducting levitation

NASA Astrophysics Data System (ADS)

Basaran, Sinan; Sivrioglu, Selim

2017-03-01

The goal of this research study is the maximization of the levitation force in a flywheel system by the use of more than one permanent magnet with a single ring-shaped HTS material. An analytical model for the radial stiffness of the ring HTS-PM is derived using the frozen image approach. The experimental works are carried out for different polarizations of the permanent magnets, and radial stiffness values are obtained from the radial force measurements. The rotational test of the flywheel system is also realized for different cases. Finally, natural frequencies of the flywheel superconducting magnetic bearing system are experimentally obtained for different combinations of the permanent magnets using a frequency analyzer.

Mixed-mu superconducting bearings

DOEpatents

Hull, John R.; Mulcahy, Thomas M.

1998-01-01

A mixed-mu superconducting bearing including a ferrite structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet structure. The ferrite structure is levitated by said stationary permanent magnet structure.

Memory effects on mechanically stimulated electric signal; diversification of stimuli impact on material memory and comments on the observed features

NASA Astrophysics Data System (ADS)

Kyriazis, Panagiotis; Stavrakas, Ilias; Anastasiadis, Cimon; Triantis, Dimos; Stonham, John

2010-05-01

Memory is defined as the ability of marble and generally of brittle geomaterials to retain 'imprints' from previous treatments and to reproduce information about these treatments under certain conditions, by analogy to the memory of human beings. Memory effects have been observed in the evolution of a variety of physical properties like the acoustic emissions of brittle materials during fracture. The existence of memory effects for the mechanically stimulated electric signal, either by Pressure (PSC) or by Bending (BSC), is examined in this work, alongside with an attempt to distinguish between the two different manifestations of 'memory' based on the electrification mechanism that is triggered at different levels of externally applied load on samples. Having identified two main mechanisms (i.e. the dynamic and the cracking) and following the human memory model, we suggest the separation of memory of a material specimen into two levels i.e. the short or temporary and long or permanent memory. For the observation and analysis of the short memory of brittle materials we have conducted experiments using the PSC technique in marble specimens. The materials are imposed to cyclic stepwise loading of the same level, scheme and direction (axial stress - unchanged position of material) in order to comply with the conditions that are proposed as suitable for memory effects study by other researchers. We have also conducted experimental tests of cyclic high level stepwise loading on amphibolite rock specimens in order to verify and study the existence of permanent memory effects. Modelling the signal recordings and studying the effects of memory on the signals, we have identified certain trends manifestation for the two types of memory that are summarised to the following points. (a) Both types of memory influence the PSC peaks evolution (exponential decrease) in cyclic loadings of the same level. (b) Permanent memory cannot be erased and affects PSC signal permanently and severely. (c) The short memory has temporary influence on the PSC signal and the impacts on the signal are milder. The main properties of the PSC signal, which are affected by the existence of memory, converge to an inertial attitude of the material to the same stimuli and they are quite common with the properties of other fracture induced signals (i.e. AE). Namely, they are the following: (a) The PSC peak evolution over loading cycles is a changing signal property either in the case of permanent or of temporary memory, with respect to the time interval between events, especially in the latter case. (b) The decrease of the dissipated electric energy during cyclic loading tests. (c) The PSC slower relaxation in each loading, quantified by the relaxation process parameters evolution. (d) The PSC signal response delay in each loading cycle increase The existence of memory effects on the mechanically stimulated electric signal is an indication that information about the deformation history (paleostresses) of the material reside inside the material. Under certain conditions such information can be revealed by analysis of the PSC signal response to specific external mechanical triggering.

Short-Term and Long-Term Effects of Orthopedic Biodegradable Implants

PubMed Central

Amini, Ami R.; Wallace, James S.; Nukavarapu, Syam P.

2012-01-01

Presently, orthopedic and oral/maxillofacial implants represent a combined $2.8 billion market, a figure expected to experience significant and continued growth. Although traditional permanent implants have been proved clinically efficacious, they are also associated with several drawbacks, including secondary revision and removal surgeries. Non-permanent, biodegradable implants offer a promising alternative for patients, as they provide temporary support and degrade at a rate matching tissue formation, and thus, eliminate the need for secondary surgeries. These implants have been in clinical use for nearly 25 years, competing directly with, or maybe even exceeding, the performance of permanent implants. The initial implantation of biodegradable materials, as with permanent materials, mounts an acute host inflammatory response. Over time, the implant degradation profile and possible degradation product toxicity mediate long-term biodegradable implant-induced inflammation. However, unlike permanent implants, this inflammation is likely to cease once the material disappears. Implant-mediated inflammation is a critical determinant for implant success. Thus, for the development of a proactive biodegradable implant that has the ability to promote optimal bone regeneration and minimal detrimental inflammation, a thorough understanding of short- and long-term inflammatory events is required. Here, we discuss an array of biodegradable orthopedic implants, their associated short- and long- term inflammatory effects, and methods to mediate these inflammatory events. PMID:22043969

Experimental transient and permanent deformation studies of steel-sphere-impacted or explosively-impulsed aluminum panels

NASA Technical Reports Server (NTRS)

Witmer, E. A.; Merlis, F.; Rodal, J. J. A.; Stagliano, T. R.

1977-01-01

The sheet explosive loading technique (SELT) was employed to obtain elastic-plastic, large deflection 3-d transient and/or permanent strain data on simple well defined structural specimens and materials: initially-flat 6061-T651 aluminum panels with all four sides ideally clamped via integral construction. The SELT loading technique was chosen since it is both convenient and provides "forcing function information" of small uncertainty. These data will be useful for evaluating pertinent 3-d structural response prediction methods.

Perspectives on Permanent Magnetic Materials for Energy Conversion and Power Generation

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

Lewis, LH; Jimenez-Villacorta, F

2012-07-18

Permanent magnet development has historically been driven by the need to supply larger magnetic energy in ever smaller volumes for incorporation in an enormous variety of applications that include consumer products, transportation components, military hardware, and clean energy technologies such as wind turbine generators and hybrid vehicle regenerative motors. Since the 1960s, the so-called rare-earth "supermagnets," composed of iron, cobalt, and rare-earth elements such as Nd, Pr, and Sm, have accounted for the majority of global sales of high-energy-product permanent magnets for advanced applications. In rare-earth magnets, the transition-metal components provide high magnetization, and the rare-earth components contribute a verymore » large magnetocrystalline anisotropy that donates high resistance to demagnetization. However, at the end of 2009, geopolitical influences created a worldwide strategic shortage of rare-earth elements that may be addressed, among other actions, through the development of rare-earth-free magnetic materials harnessing sources of magnetic anisotropy other than that provided by the rare-earth components. Materials engineering at the micron scale, nanoscale, and Angstrom scales, accompanied by improvements in the understanding and characterization of nanoscale magnetic phenomena, is anticipated to result in new types of permanent magnetic materials with superior performance. DOI: 10.1007/s11661-012-1278-2 (C) The Minerals, Metals & Materials Society and ASM International 2012« less

The influence of the lining material on the repair of the infected dentin in young permanent molars after restoration: A randomized clinical trial

PubMed Central

Kuhn, Eunice; Reis, Alessandra; Chibinski, Ana Claudia Rodrigues; Wambier, Denise Stadler

2016-01-01

Aim: This study evaluated the impact of liner material on the fluorescence, morphological and mineral characteristics of permanent carious dentin after cavity sealing. Methods: Thirty children (11.0 ± 2.7 years old) presenting at least one active deep carious lesion in permanent molars were selected. Fragments of carious dentin were removed from teeth before lining the cavity (baseline samples) with high-viscosity glass ionomer cement (G1) or an inert material (wax - G2). Cavities were restored with composite resin and reopened 60 days later, and other fragments were removed (60-day sample). The laser fluorescence (LF) readings and morphological and mineral changes of both groups were compared. Results: After 60 days, forty teeth were available for evaluation. Lower LF means were obtained (Wilcoxon signed-rank test; P < 0.05), and enhanced calcium and phosphorus levels were detected for both groups (t-test, P < 0.05). An uptake of fluorine was observed only in G1 (t-test; P < 0.05). Regardless of the group, baseline samples exhibited clear signs of bacterial invasion, and the collagen fibers were exposed; the 60-day samples showed a better-organized tissue with a more compact intertubular dentin. Conclusion: Caries arrestment with dentin reorganization occurs regardless of the lining material placed in contact with the infected dentin. PMID:27994311

Study and review of permanent magnets for electric vehicle propulsion motors

NASA Technical Reports Server (NTRS)

Strnat, K. J.

1983-01-01

A study of permanent magnets (PM) was performed in support of the DOE/NASA electric and hybrid vehicle program. PM requirements for electric propulsion motors are analyzed, design principles and relevant properties of magnets are discussed. Available PM types are reviewed. For the needed high-grade magnets, design data, commercial varieties and sources are tabulated, based on a survey of vendors. Economic factors such as raw material availability, production capability and cost are analyzed, especially for cobalt and the rare earths. Extruded Mn-Al-C magnets from Japan were experimentally characterized. Dynamic magnetic data for the range -50 deg to +150 deg C and some mechanical properties are reported. The state of development of the important PM material families is reviewed. Feasible improvements or new developments of magnets for electric vehicle motors are identified.

A study of generator performance with linear permanent magnet in various coil configuration and rotor-stator geometry

NASA Astrophysics Data System (ADS)

Asy'ari, Hasyim; Sarjito, Prasetio, Septian Heri

2017-04-01

The aim of the research work describe in this paper was to design and optimize a permanent magnet linear generator for renewable energy power plants. It is cover of first stage of designing stator and rotor permanent magnet linear generator. Stator design involves determining dimensions, number of slots, diameter of wire, and the number of winding in each slot. The design of the rotor includes rotor manufacture of PVC pipe material, 10 pieces of permanent magnet type ferrite 271 mikroweber, and resin. The second stage was to assemble the stator and rotor that has been done in the first stage to be a permanent magnet linear generator. The third stage was to install a permanent magnet linear generator with induction motors. Further stage was to test performance of a permanent magnet linear generator by utilizing of induction motor as a prime mover experimentally. In this study, permanent magnet linear generator with a rotor consists of five pairs of permanent magnets. The stator consists of 6 slots of the stator frame, each slot mounted stator coil of 200, 300, 400, 500, and 800 windings, and dimensions of wire used was 0.4 mm. The stator frame was made from acrylic. Results of the experiment that, permanent magnet linear generator when no load was able to generate a DC voltage of 14.5 volts at 300 rpm, and at the output of the linear generator when it is connected to the DC fan as a load only generated of 6.7 volts. It concludes that permanent magnet linear generator output can be used as an input device hybrid system. Data obtained from this experiment in laboratory scale can be developed in a larger scale by varying the type of magnet being used, the number of windings, and the speed used to generate more power.

Mixed-mu superconducting bearings

DOEpatents

Hull, J.R.; Mulcahy, T.M.

1998-03-03

A mixed-mu superconducting bearing is disclosed including a ferrite structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet structure. The ferrite structure is levitated by said stationary permanent magnet structure. 9 figs.

Method for forming permanent magnets with different polarities for use in microelectromechanical devices

DOEpatents

Roesler, Alexander W [Tijeras, NM; Christenson, Todd R [Albuquerque, NM

2007-04-24

Methods are provided for forming a plurality of permanent magnets with two different north-south magnetic pole alignments for use in microelectromechanical (MEM) devices. These methods are based on initially magnetizing the permanent magnets all in the same direction, and then utilizing a combination of heating and a magnetic field to switch the polarity of a portion of the permanent magnets while not switching the remaining permanent magnets. The permanent magnets, in some instances, can all have the same rare-earth composition (e.g. NdFeB) or can be formed of two different rare-earth materials (e.g. NdFeB and SmCo). The methods can be used to form a plurality of permanent magnets side-by-side on or within a substrate with an alternating polarity, or to form a two-dimensional array of permanent magnets in which the polarity of every other row of the array is alternated.

Post-assembly magnetization of a 100 kW high speed permanent magnet rotor.

PubMed

Lv, Yiliang; Wang, Guobin; Li, Liang

2015-03-01

A post-assembly magnetizing fixture has been designed and successfully used to magnetize the rotor of a 100 kW high speed permanent magnet synchronous motor. The rotor is a solid cylinder with outer diameter of 80 mm and total length of 515 mm. The permanent magnet material is samarium-cobalt (Sm2Co17) with saturation magnetizing field of 6 T. The mechanical stability of the magnetizing fixture has been studied as well as the general design methodology. The magnetizing coil is subdivided in order to reduce the electromagnetic force, and the coils are separately reinforced in different ways. The electromagnetic and structural optimization is performed by finite element analysis and verified by experiments.

Permanent magnet edge-field quadrupole

DOEpatents

Tatchyn, R.O.

1997-01-21

Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis. 10 figs.

Permanent magnet edge-field quadrupole

DOEpatents

Tatchyn, Roman O.

1997-01-01

Planar permanent magnet edge-field quadrupoles for use in particle accelerating machines and in insertion devices designed to generate spontaneous or coherent radiation from moving charged particles are disclosed. The invention comprises four magnetized rectangular pieces of permanent magnet material with substantially similar dimensions arranged into two planar arrays situated to generate a field with a substantially dominant quadrupole component in regions close to the device axis.

Modeling of non-ideal hard permanent magnets with an affine-linear model, illustrated for a bar and a horseshoe magnet

NASA Astrophysics Data System (ADS)

Glane, Sebastian; Reich, Felix A.; Müller, Wolfgang H.

2017-11-01

This study is dedicated to continuum-scale material modeling of isotropic permanent magnets. An affine-linear extension to the commonly used ideal hard model for permanent magnets is proposed, motivated, and detailed. In order to demonstrate the differences between these models, bar and horseshoe magnets are considered. The structure of the boundary value problem for the magnetic field and related solution techniques are discussed. For the ideal model, closed-form analytical solutions were obtained for both geometries. Magnetic fields of the boundary value problems for both models and differently shaped magnets were computed numerically by using the boundary element method. The results show that the character of the magnetic field is strongly influenced by the model that is used. Furthermore, it can be observed that the shape of an affine-linear magnet influences the near-field significantly. Qualitative comparisons with experiments suggest that both the ideal and the affine-linear models are relevant in practice, depending on the magnetic material employed. Mathematically speaking, the ideal magnetic model is a special case of the affine-linear one. Therefore, in applications where knowledge of the near-field is important, the affine-linear model can yield more accurate results—depending on the magnetic material.

Alkaline "Permanent" Paper.

ERIC Educational Resources Information Center

Pacey, Antony

1991-01-01

Discussion of paper manufacturing processes and their effects on library materials focuses on the promotion of alkaline "permanent" paper, with less acid, by Canadian library preservation specialists. Standards for paper acidity are explained; advantages of alkaline paper are described, including decreased manufacturing costs; and…

Model of the material removal function and an experimental study on a magnetorheological finishing process using a small ball-end permanent-magnet polishing head.

PubMed

Chen, Mingjun; Liu, Henan; Cheng, Jian; Yu, Bo; Fang, Zhen

2017-07-01

In order to achieve the deterministic finishing of optical components with concave surfaces of a curvature radius less than 10 mm, a novel magnetorheological finishing (MRF) process using a small ball-end permanent-magnet polishing head with a diameter of 4 mm is introduced. The characteristics of material removal in the proposed MRF process are studied. The model of the material removal function for the proposed MRF process is established based on the three-dimensional hydrodynamics analysis and Preston's equation. The shear stress on the workpiece surface is calculated by means of resolving the presented mathematical model using a numerical solution method. The analysis result reveals that the material removal in the proposed MRF process shows a positive dependence on shear stress. Experimental research is conducted to investigate the effect of processing parameters on the material removal rate and improve the surface accuracy of a typical rotational symmetrical optical component. The experimental results show that the surface accuracy of the finished component of K9 glass material has been improved to 0.14 μm (PV) from the initial 0.8 μm (PV), and the finished surface roughness Ra is 0.0024 μm. It indicates that the proposed MRF process can be used to achieve the deterministic removal of surface material and perform the nanofinishing of small curvature radius concave surfaces.

Expanding hollow metal rings

DOEpatents

Peacock, Harold B [Evans, GA; Imrich, Kenneth J [Grovetown, GA

2009-03-17

A sealing device that may expand more planar dimensions due to internal thermal expansion of a filler material. The sealing material is of a composition such that when desired environment temperatures and internal actuating pressures are reached, the sealing materials undergoes a permanent deformation. For metallic compounds, this permanent deformation occurs when the material enters the plastic deformation phase. Polymers, and other materials, may be using a sealing mechanism depending on the temperatures and corrosivity of the use. Internal pressures are generated by either rapid thermal expansion or material phase change and may include either liquid or solid to gas phase change, or in the gaseous state with significant pressure generation in accordance with the gas laws. Sealing material thickness and material composition may be used to selectively control geometric expansion of the seal such that expansion is limited to a specific facing and or geometric plane.

A Lightweight, Direct-Drive, Fully Superconducting Generator for Large Wind Turbines

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

Meinke, Rainer; Morrison, Darrell; Prince, Vernon Gregory

2014-12-31

The current trend in the offshore wind turbine industry favors direct-drive generators based on permanent magnets, as they allow for a simple and reliable drivetrain without a gearbox. These generators, however, do not scale very well to high power levels beneficial for offshore wind, and their use in wind turbines over 6 MW is questionable in terms of mass and economic feasibility. Moreover, rare earth materials composing the permanent magnets are becoming less available, more costly and potentially unavailable in the foreseeable future. A stated goal of the DOE is a critical materials strategy that pursues the development of substitutemore » materials and technology for rare earth materials to improve supply chain flexibility and meet the needs of the clean energy economy.Therefore, alternative solutions are needed, in terms of both favorable up-scaling and minimizing or eliminating the use of permanent magnets. The generator design presented in this document addresses both these issues with the development of a fully superconducting generator (FSG) with unprecedented high specific torque. A full-scale, 10-MW, 10-rpm generator will weigh less about 150 metric tons, compared to 300 metric tons for an equivalent direct-drive, permanent magnet generator. The developed concept does not use any rare earth materials in its critical drive components, but rather relies on a superconductor composed of mainly magnesium and boron (MgB2), both of which are in abundant supply from multiple global sources.« less

The age of permanent tooth emergence in children of different ethnic origin in the Auckland region: a cross-sectional study.

PubMed

Kanagaratnam, Sathananthan; Schluter, Philip J

2012-06-01

To report robust and contemporary estimates of permanent teeth emergence ages in children of Māori, Pasifika, Chinese, Indian and European ethnic origin in the Auckland region. A stratified, two-stage cross-sectional study. Strata were defined by school decile status. Schools defined the first-stage sampling unit, and students the second stage. Invitations and consent forms were distributed to eligible participants at school for completion at home. Participants were examined at school-based clinics or in a mobile clinic. PARTICIPANTS/MATERIALS, AND METHODS: Children aged between 5 and 13 years enrolled within the Auckland Regional Dental Service. Schools were randomly selected and then all students within selected schools were invited to participate. Eligible participants completing a consent form had an additional tooth assessment that complemented their routine dental examination. A generalised gamma failure-time model was employed to estimate permanent tooth eruption ages. Visually based assessment of permanent tooth emergence. Overall, 3,466 children participated. Differences in median permanent tooth emergence ages were seen among ethnic groups and sexes (P < or = 0.01). Pasifika children had earlier median eruption time than sex-matched Māori children, who (in turn) were more advanced than sex-matched European children. Median eruption age occurred earlier in girls than boys for all permanent teeth. Despite known demographic, geographic and ethnic differences, estimates of permanent teeth emergence timing widely used in New Zealand are based on historical overseas populations. The presented estimates provide new standards and may be more appropriate for dental therapists and dentists when assessing permanent teeth emergence in New Zealand children.

Concrete: Potential material for Space Station

NASA Technical Reports Server (NTRS)

Lin, T. D.

1992-01-01

To build a permanent orbiting space station in the next decade is NASA's most challenging and exciting undertaking. The space station will serve as a center for a vast number of scientific products. As a potential material for the space station, reinforced concrete was studied, which has many material and structural merits for the proposed space station. Its cost-effectiveness depends on the availability of lunar materials. With such materials, only 1 percent or less of the mass of a concrete space structure would have to be transported from earth.

Fe-Cluster Compounds of Chalcogenides: Candidates for Rare-Earth-Free Permanent Magnet and Magnetic Nodal-Line Topological Material.

PubMed

Zhao, Xin; Wang, Cai-Zhuang; Kim, Minsung; Ho, Kai-Ming

2017-12-04

Fe-cluster-based crystal structures are predicted for chalcogenides Fe 3 X 4 (X = S, Se, Te) using an adaptive genetic algorithm. Topologically different from the well-studied layered structures of iron chalcogenides, the newly predicted structures consist of Fe clusters that are either separated by the chalcogen atoms or connected via sharing of the vertex Fe atoms. Using first-principles calculations, we demonstrate that these structures have competitive or even lower formation energies than the experimentally synthesized Fe 3 X 4 compounds and exhibit interesting magnetic and electronic properties. In particular, we show that Fe 3 Te 4 can be a good candidate as a rare-earth-free permanent magnet and Fe 3 S 4 can be a magnetic nodal-line topological material.

Experimental transient and permanent deformation studies of steel-sphere-impacted or impulsively-loaded aluminum beams with clamped ends

NASA Technical Reports Server (NTRS)

Witmer, E. A.

1975-01-01

The sheet explosive loading technique (SELT) was employed to obtain elastic-plastic, large-deflection transient and/or permanent strain data on simple well-defined structural specimens and materials: initially-flat 6061-T651 aluminum beams with both ends ideally clamped via integral construction. The SELT loading technique was chosen since it is both convenient and provides forcing function information of small uncertainty. These data will be useful for evaluating pertinent structural response prediction methods. A second objective was to obtain high-quality transient-strain data for a well-defined structural/material model subjected to impact by a rigid body of known mass, impact velocity, and geometry; large-deflection, elastic-plastic transient response conditions are of primary interest. The beam with both ends clamped and a steel sphere as the impacting body were chosen. The steel sphere was launched vertically by explosive propulsion to achieve various desired impact velocities. The sphere/beam impact tests resulted in producing a wide range of structural responses and permanent deformations, including rupture of the beam from excessive structural response in two cases. The transient and permanent strain data as well as the permanent deflection data obtained are of high quality and should be useful for checking and evaluating methods for predicting the responses of simple 2-d structures to fragment (sphere) impact. Transient strain data very close to the point of impact were not obtained over as long a time as desirable because the gage(s) in that region became detached during the transient response.

A clinical evaluation of mineral trioxide aggregate for root-end closure of non-vital immature permanent incisors in children-a pilot study.

PubMed

Sarris, Spyridoula; Tahmassebi, Jinous F; Duggal, Monty S; Cross, Ian A

2008-02-01

The aim of this pilot study was to evaluate the clinical efficacy of mineral trioxide aggregate (MTA) as an apexification material when used in non-vital immature permanent incisors in children. Fifteen children with a mean age of 11.7 years and 17 non-vital permanent incisors were ajudged suitable for inclusion. Standard endodontic procedures were followed and an apical plug of 3-4 mm was created by using MTA after a calcium hydroxide intracanal dressing had been applied for at least 1 week. Final obturation was completed by using thermoplastisized Gutta-Percha (Obtura II) at least 1 week following MTA placement. Subjects were reviewed clinically and radiographically at 3-month intervals. Mean follow-up time for MTA was 12.53 months (+/-2.94 SD). Of the total of 17 teeth treated, MTA placement was considered to be adequate in 13 teeth. The procedure showed clinical success in 94.1% of the cases, radiographic success was found to be 76.5% and in further three cases (17.6%) the outcome was considered to be uncertain. This is one of the very few studies that have reported the out coming of MTA as an apexification material in children with non-vital teeth and incomplete root development. However, larger clinical studies are required to evaluate the long-term success of this procedure.

Analysis and Design Considerations of a High-Power Density, Dual Air Gap, Axial-Field Brushless, Permanent Magnet Motor.

NASA Astrophysics Data System (ADS)

Cho, Chahee Peter

1995-01-01

Until recently, brush dc motors have been the dominant drive system because they provide easily controlled motor speed over a wide range, rapid acceleration and deceleration, convenient control of position, and lower product cost. Despite these capabilities, the brush dc motor configuration does not satisfy the design requirements for the U.S. Navy's underwater propulsion applications. Technical advances in rare-earth permanent magnet materials, in high-power semiconductor transistor technology, and in various rotor position-sensing devices have made using brushless permanent magnet motors a viable alternative. This research investigates brushless permanent magnet motor technology, studying the merits of dual-air gap, axial -field, brushless, permanent magnet motor configuration in terms of power density, efficiency, and noise/vibration levels. Because the design objectives for underwater motor applications include high-power density, high-performance, and low-noise/vibration, the traditional, simplified equivalent circuit analysis methods to assist in meeting these goals were inadequate. This study presents the development and verification of detailed finite element analysis (FEA) models and lumped parameter circuit models that can calculate back electromotive force waveforms, inductance, cogging torque, energized torque, and eddy current power losses. It is the first thorough quantification of dual air-gap, axial -field, brushless, permanent magnet motor parameters and performance characteristics. The new methodology introduced in this research not only facilitates the design process of an axial field, brushless, permanent magnet motor but reinforces the idea that the high-power density, high-efficiency, and low-noise/vibration motor is attainable.

Highly stable and finely tuned magnetic fields generated by permanent magnet assemblies.

PubMed

Danieli, E; Perlo, J; Blümich, B; Casanova, F

2013-05-03

Permanent magnetic materials are the only magnetic source that can be used to generate magnetic fields without power consumption or maintenance. Such stand-alone magnets are very attractive for many scientific and engineering areas, but they suffer from poor temporal field stability, which arises from the strong sensitivity of the magnetic materials and mechanical support to temperature variation. In this work, we describe a highly efficient method useful to cancel the temperature coefficient of permanent magnet assemblies in a passive and accurate way. It is based on the combination of at least two units made of magnetic materials with different temperature coefficients arranged in such a way that the ratio of the fields generated by each unit matches the ratio of their effective temperature coefficients defined by both the magnetic and mechanical contributions. Although typically available magnetic materials have negative temperature coefficients, the cancellation is achieved by aligning the fields generated by each unit in the opposite direction. We demonstrate the performance of this approach by stabilizing the field generated by a dipolar Halbach magnet, recently proposed to achieve high field homogeneity. Both the field drift and the homogeneity are monitored via nuclear magnetic resonance spectroscopy experiments. The results demonstrate the compatibility of the thermal compensation approach with existing strategies useful to fine-tune the spatial dependence of the field generated by permanent magnet arrays.

Low-loss, high-speed, high-T.sub.c superconducting bearings

DOEpatents

Hull, John R.; Mulcahy, Thomas M.; Uherka, Kenneth L.

1997-01-01

A flywheel energy storage device including an iron structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet. The stationary permanent magnet levitates the iron structure while the superconductor structure can stabilize the rotating iron structure.

Vibration converter with magnetic levitation

NASA Astrophysics Data System (ADS)

Gladilin, A. V.; Pirogov, V. A.; Golyamina, I. P.; Kulaev, U. V.; Kurbatov, P. A.; Kurbatova, E. P.

2015-05-01

The paper presents a mathematical model, the results of computational and theoretical research, and the feasibility of creating a vibration converter with full magnetic levitation in the suspension of a high-temperature superconductor (HTSC). The axial and radial stability of the active part of the converter is provided by the interaction of the magnetic field of ring-shaped permanent magnets and a hollow cylinder made of the ceramic HTSC material. The force is created by a system of current-carrying coils whose magnetic field is polarized by permanent magnets and interacts with induced currents in the superconducting cylinder. The case of transition to the superconducting state of HTSC material in the field of the permanent magnets (FC mode) is considered. The data confirm the outlook for the proposed technical solutions.

Viscoelastic stability of resin-composites aged in food-simulating solvents.

PubMed

Marghalani, Hanadi Y; Watts, David C

2013-09-01

To study time-dependent viscoelastic deformation (creep and recovery) of resin-composites, after conditioning in food-simulating solvents, under a compressive stress at 37°C. Five dimethacrylate-based composites: (Spectrum TPH, Premise Body, Tetric Ceram HB, Filtek P60, X-tra fil), and two Ormocers (Experimental Ormocer V 28407, Admira) were studied. Three groups of cylindrical specimens (4mm×6mm) were prepared and then conditioned in 3 solvents: methyl ethyl ketone (MEK), ethanol, and water for 1 month at 37°C. The compressive creep-strain under 35MPa in 37°C water was recorded continuously for 2h and then the unloaded recovery-strain was monitored for another 2h. The data were analyzed by one-way ANOVA and Bonferroni's test. The materials all exhibited classic creep and recovery curves, with most parameters being significantly different (p<0.0001) for each solvent condition. All materials showed lower creep-strain in water than in ethanol or MEK solvents. Maximum creep-strain and permanent-set gave negative linear-regression (r(2)>0.98) with logarithm of the solvent solubility-parameter. The % mean (SD) creep-strain ranged from a minimum of 0.82 (0.01) for the Exp. Ormocer in water to the maximum of 4.19 (0.30) for Admira in MEK. Similar trends were found for permanent-set. The dimethacrylate-based composites behaved as an intermediate group, apart from X-tra fil that had similar stability to the Exp. Ormocer. The viscoelastic stability (low creep and permanent-set) of the Exp. Ormocer, compared to many dimethacrylate-based composites, in food-simulating solvents may be due to its diluent-free formulation. This was closely matched by a highly-filled dimethacrylate material (X-tra fil). Copyright © 2013 Academy of Dental Materials. All rights reserved.

Remediation of hydrophobic, persistent pollutants using a magnetic permanently confined micelle array (Mag-PCMA)

NASA Astrophysics Data System (ADS)

Clark, K. K.; Keller, A. A.

2009-12-01

Natural and anthropogenic factors have resulted in the deposition of hydrophobic organic contaminants (HOCs) like PAHs and PCBs in elevated levels in soils and sediments. Currently there are 150 Superfund sites in the United States with contaminated sediments. Dredging is the most common practice for restoring Superfund sites to their preexisting conditions; this requires the transport of large volumes of material off-site for additional storage or processing. Our lab has designed a nano-hybrid material that can be used on-site; it combines a magnetic nanoscale iron oxide core coated with a cationic surfactant and is encased in a mesoporous silica matrix, called magnetic permanently confined micelle arrays, (Mag-PCMAs). This sorbent has been designed to remove HOCs from such scenarios. Surfactants are important in the enhancement of transport from binding sites in nature, such as organic matter, onto sorbents and other recoverable materials. The sorbent’s magnetic core allows for rapid separation by applying a magnetic field. It has also been shown to be reusable and maintain a removal efficiency of 95% over five cycles of reuse. Preliminary sorption studies show that the sorbent is capable of removing up to 98% of hydrophobic compounds from aqueous media. Current sorption studies are being done to test the efficiency of removing PAHs and PCBs from sediments, soils, and suspended sediments. Physicochemical properties that will influence the desorption/sorption hysteresis are being characterized to determine which properties enhance desorption from the contaminated media onto the Mag-PCMAs. Relevant applications are diverse as this material has the potential to recover a variety of HOCs in both ex situ and in situ remediation scenarios. Magnetic Permanently Confined Micelle Arrays

Bearing design for flywheel energy storage using high-TC superconductors

DOEpatents

Hull, John R.; Mulcahy, Thomas M.

2000-01-01

A high temperature superconductor material bearing system (38) This system (38) includes a rotor (50) having a ring permanent magnet (60), a plurality of permanent magnets (16, 20 and 70) for interacting to generate levitation forces for the system (38). This group of magnets are a push/pull bearing (75). A high temperature superconductor structure (30) interacts with the ting permanent magnet (60) to provide stabilizing forces for the system (38).

Low-loss, high-speed, high-{Tc} superconducting bearings

DOEpatents

Hull, J.R.; Mulcahy, T.M.; Uherka, K.L.

1997-06-24

A flywheel energy storage device is disclosed including an iron structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet. The stationary permanent magnet levitates the iron structure while the superconductor structure can stabilize the rotating iron structure. 15 figs.

Low-loss, high-speed, high-T.sub.C superconducting bearings

DOEpatents

Hull, John R.; Mulcahy, Thomas M.; Uherka, Kenneth L.

1996-01-01

A flywheel energy storage device including an iron structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet. The stationary permanent magnet levitates the iron structure while the superconductor structure can stabilize and levitate the rotating iron structure.

Permanent magnet with MgB{sub 2} bulk superconductor

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

Yamamoto, Akiyasu, E-mail: yamamoto@appchem.t.u-tokyo.ac.jp; JST-PRESTO, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012; Ishihara, Atsushi

2014-07-21

Superconductors with persistent zero-resistance currents serve as permanent magnets for high-field applications requiring a strong and stable magnetic field, such as magnetic resonance imaging. The recent global helium shortage has quickened research into high-temperature superconductors (HTSs)—materials that can be used without conventional liquid-helium cooling to 4.2 K. Herein, we demonstrate that 40-K-class metallic HTS magnesium diboride (MgB{sub 2}) makes an excellent permanent bulk magnet, maintaining 3 T at 20 K for 1 week with an extremely high stability (<0.1 ppm/h). The magnetic field trapped in this magnet is uniformly distributed, as for single-crystalline neodymium-iron-boron. Magnetic hysteresis loop of the MgB{sub 2} permanent bulkmore » magnet was determined. Because MgB{sub 2} is a simple-binary-line compound that does not contain rare-earth metals, polycrystalline bulk material can be industrially fabricated at low cost and with high yield to serve as strong magnets that are compatible with conventional compact cryocoolers, making MgB{sub 2} bulks promising for the next generation of Tesla-class permanent-magnet applications.« less

Fe-Cluster Compounds of Chalcogenides: Candidates for Rare-Earth-Free Permanent Magnet and Magnetic Nodal-Line Topological Material

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

Zhao, Xin; Wang, Cai-Zhuang; Kim, Minsung

Here, Fe-cluster-based crystal structures are predicted for chalcogenides Fe 3X 4 (X = S, Se, Te) using an adaptive genetic algorithm. Topologically different from the well-studied layered structures of iron chalcogenides, the newly predicted structures consist of Fe clusters that are either separated by the chalcogen atoms or connected via sharing of the vertex Fe atoms. Additionally, using first-principles calculations, we demonstrate that these structures have competitive or even lower formation energies than the experimentally synthesized Fe 3X 4 compounds and exhibit interesting magnetic and electronic properties. In particular, we show that Fe 3X 4 can be a good candidatemore » as a rare-earth-free permanent magnet and Fe 3X 4 can be a magnetic nodal-line topological material.« less

Fe-Cluster Compounds of Chalcogenides: Candidates for Rare-Earth-Free Permanent Magnet and Magnetic Nodal-Line Topological Material

DOE PAGES

Zhao, Xin; Wang, Cai-Zhuang; Kim, Minsung; ...

2017-11-13

Here, Fe-cluster-based crystal structures are predicted for chalcogenides Fe 3X 4 (X = S, Se, Te) using an adaptive genetic algorithm. Topologically different from the well-studied layered structures of iron chalcogenides, the newly predicted structures consist of Fe clusters that are either separated by the chalcogen atoms or connected via sharing of the vertex Fe atoms. Additionally, using first-principles calculations, we demonstrate that these structures have competitive or even lower formation energies than the experimentally synthesized Fe 3X 4 compounds and exhibit interesting magnetic and electronic properties. In particular, we show that Fe 3X 4 can be a good candidatemore » as a rare-earth-free permanent magnet and Fe 3X 4 can be a magnetic nodal-line topological material.« less

49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

Code of Federal Regulations, 2012 CFR

2012-10-01

... (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS...; or (2) Repaired by a method that reliable engineering tests and analyses show can permanently restore...

49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

Code of Federal Regulations, 2011 CFR

2011-10-01

... (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS...; or (2) Repaired by a method that reliable engineering tests and analyses show can permanently restore...

49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

Code of Federal Regulations, 2013 CFR

2013-10-01

... (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS...; or (2) Repaired by a method that reliable engineering tests and analyses show can permanently restore...

49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

Code of Federal Regulations, 2014 CFR

2014-10-01

... (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS...; or (2) Repaired by a method that reliable engineering tests and analyses show can permanently restore...

Microfilm Permanence and Archival Quality

ERIC Educational Resources Information Center

Avedon, Don M.

1972-01-01

The facts about microfilm permanence and archival quality are presented in simple terms. The major factors, including the film base material, the film emulsion, processing, and storage conditions are reviewed. The designations on the edge of the film are explained and a list of refernces provided. (14 references) (Author)

49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

Code of Federal Regulations, 2010 CFR

2010-10-01

... (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS...; or (2) Repaired by a method that reliable engineering tests and analyses show can permanently restore...

Low-loss, high-speed, high-{Tc} superconducting bearings

DOEpatents

Hull, J.R.; Mulcahy, T.M.; Uherka, K.L.

1996-07-30

A flywheel energy storage device is disclosed including an iron structure disposed for rotation adjacent a stationary superconductor material structure and a stationary permanent magnet. The stationary permanent magnet levitates the iron structure while the superconductor structure can stabilize and levitate the rotating iron structure. 15 figs.

Permanent laser conditioning of thin film optical materials

DOEpatents

Wolfe, C. Robert; Kozlowski, Mark R.; Campbell, John H.; Staggs, Michael; Rainer, Frank

1995-01-01

The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold.

Overview of NORM and activities by a NORM licensed permanent decontamination and waste processing facility

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

Mirro, G.A.

1997-02-01

This paper presents an overview of issues related to handling NORM materials, and provides a description of a facility designed for the processing of NORM contaminated equipment. With regard to handling NORM materials the author discusses sources of NORM, problems, regulations and disposal options, potential hazards, safety equipment, and issues related to personnel protection. For the facility, the author discusses: description of the permanent facility; the operations of the facility; the license it has for handling specific radioactive material; operating and safety procedures; decontamination facilities on site; NORM waste processing capabilities; and offsite NORM services which are available.

Evaluation of bond strength of self-etching adhesives having different pH on primary and permanent teeth dentin.

PubMed

Ozmen, Bilal; Koyuturk, Alp Erdin; Tokay, Ugur; Cortcu, Murat; Sari, Mustafa Erhan

2015-10-16

The purpose of this in vitro study was to evaluate the dentin shear bond strength of 4 self-etching adhesives having a different pH on primary and permanent teeth dentin. The occlusal enamel was removed from 60 freshly extracted third molar and 60 primary second molar human teeth, which were randomly separated into 4 groups (n = 15). Four adhesive systems were applied: G-Bond (GC Corporation, Tokyo, Japan, pH: 1.5), Futura Bond M (Voco, Cuxhaver, Germany, pH: 1.4), Adper Prompt L-Pop (3M/ESPE, St Paul, MN, USA, pH: 0.8), and Clearfil S(3) Bond (Kuraray Medical, Tokyo, Japan, pH: 2.7) according to the manufacturer's instructions. After the application of dentin bonding agents, a composite resin material (Z250 Restorative A2, 3M ESPE, St. Paul, MN, USA) for permanent teeth and a compomer resin material (Dyract Extra A2, Dentsply, Konstanz, Germany) for primary teeth was applied onto the prepared dentin surfaces. The data were obtained by using a universal test machine at a crosshead speed of 1 mm/min. The mean values were compared using Tukey's multiple comparison test. Although there was no difference between adhesives on the permanent teeth, Clearfil S3 adhesive showed higher bond (18.07 ± 0.58 MPa) (P>0.05). Lower bond strength values were obtained from primary teeth and especially G-Bond adhesive (9.36 ± 0.48 MPa) (P<0.05). Self-etching adhesives with different pH and solvent types can be used successfully for permanent teeth dentin but adhesives with low pH did not provide greater shear bond strength values.

Testing of the permanent magnet material Mn-Al-C for potential use in propulsion motors for electric vehicles

NASA Technical Reports Server (NTRS)

Abdelnour, Z. A.; Mildrum, H. F.; Strnat, K. J.

1980-01-01

The development of Mn-Al-C permanent magnets is reviewed. The general properties of the material are discussed and put into perspective relative to alnicos and ferrites. The commercial material now available is described by the manufacturer's data. The traction motor designer's demands of a permanent magnet for potential use in electric vehicle drives are reviewed. From this, a list of the needed specific information is extracted. A plan for experimental work is made which would generate this information, or verify data supplied by the producer. The results of these measurements are presented in the form of tables and graphs. The tests determined magnetic design data and some mechanical strength properties. Easy axis hysteresis and demagnetization curves, recoil loops and other minor loop fields were measured over a temperature range from -50 C to +150 C. Hysteresis loops were also measured for three orthogonal directions (the easy and 2 hard axes of magnetization).

The use of organic markers in the differentiation of organic inputs to aquatic systems

NASA Astrophysics Data System (ADS)

Reeves, A. D.

1995-04-01

In previous projects the estuarine distributions of a variety of molecular organic markers have been described and discussed in relation to sources, transport mechanisms and fates of anthropogenic and biogenic inputs to estuaries. Molecular markers have been used successfully to establish terrestrial inputs to marine water and to trace pollutants in water-ways. One of the components selected for study was lignin. Lignin compounds are phenolic polymers that occur as major constituents of the cell walls of vascular plants. Their source, natural abundance, wide distribution and resistance to microbial degradation render them good terrestrial markers and, via their phenolic aldehyde oxidation products, afford characterisation of their source material. In previous work, ratios of various lignin components suggest that permanently suspended material contains a significant proportion of degraded angiosperm tissues whereas, in resuspended material, a component of gymnosperm material is indicated. Comparison of the lignin concentrations in the suspended material with those in underlying sediment reveals that the permanently suspended material is preferentially enriched in lignin. This is due, at least in part, to the relative buoyancy of lignin-containing prticles which causes them to float in near-surface water. This paper considers whether such methodology can be usefully applied to the determination of terrestrial inputs to lentic environments.

16 CFR 1201.2 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... introduction into commerce. (7) Door means an assembly that is installed in an interior or exterior wall; that... is one of a series of overlapping pieces of glazing material designed to admit ventilation and light... built on a permanent chassis and designed to be used as a dwelling with or without a permanent...

16 CFR § 1201.2 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... introduction into commerce. (7) Door means an assembly that is installed in an interior or exterior wall; that... is one of a series of overlapping pieces of glazing material designed to admit ventilation and light... built on a permanent chassis and designed to be used as a dwelling with or without a permanent...

16 CFR 1201.2 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... introduction into commerce. (7) Door means an assembly that is installed in an interior or exterior wall; that... is one of a series of overlapping pieces of glazing material designed to admit ventilation and light... built on a permanent chassis and designed to be used as a dwelling with or without a permanent...

16 CFR 1201.2 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... introduction into commerce. (7) Door means an assembly that is installed in an interior or exterior wall; that... is one of a series of overlapping pieces of glazing material designed to admit ventilation and light... built on a permanent chassis and designed to be used as a dwelling with or without a permanent...

16 CFR 1201.2 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... introduction into commerce. (7) Door means an assembly that is installed in an interior or exterior wall; that... is one of a series of overlapping pieces of glazing material designed to admit ventilation and light... built on a permanent chassis and designed to be used as a dwelling with or without a permanent...

Permanent laser conditioning of thin film optical materials

DOEpatents

Wolfe, C.R.; Kozlowski, M.R.; Campbell, J.H.; Staggs, M.; Rainer, F.

1995-12-05

The invention comprises a method for producing optical thin films with a high laser damage threshold and the resulting thin films. The laser damage threshold of the thin films is permanently increased by irradiating the thin films with a fluence below an unconditioned laser damage threshold. 9 figs.

Permanent-magnet multipole with adjustable strength

DOEpatents

Halbach, K.

1982-09-20

Two or more magnetically soft pole pieces are symmetrically positioned along a longitudinal axis to provide a magnetic field within a space defined by the pole pieces. Two or more permanent magnets are mounted to an external magnetically-soft cylindrical sleeve which rotates to bring the permanent magnets into closer coupling with the pole pieces and thereby adjustably control the field strength of the magnetic field produced in the space defined by the pole pieces. The permanent magnets are preferably formed of rare earth cobalt (REC) material which has a high remanent magnetic field and a strong coercive force. The pole pieces and the permanent magnets have corresponding cylindrical surfaces which are positionable with respect to each other to vary the coupling there between. Auxiliary permanent magnets are provided between the pole pieces to provide additional magnetic flux to the magnetic field without saturating the pole pieces.

Permanent magnet multipole with adjustable strength

DOEpatents

Halbach, Klaus

1985-01-01

Two or more magnetically soft pole pieces are symmetrically positioned along a longitudinal axis to provide a magnetic field within a space defined by the pole pieces. Two or more permanent magnets are mounted to an external magnetically-soft cylindrical sleeve which rotates to bring the permanent magnets into closer coupling with the pole pieces and thereby adjustably control the field strength of the magnetic field produced in the space defined by the pole pieces. The permanent magnets are preferably formed of rare earth cobalt (REC) material which has a high remanent magnetic field and a strong coercive force. The pole pieces and the permanent magnets have corresponding cylindrical surfaces which are positionable with respect to each other to vary the coupling therebetween. Auxiliary permanent magnets are provided between the pole pieces to provide additional magnetic flux to the magnetic field without saturating the pole pieces.

Crown heights in the permanent teeth of 45,X and 45,X/46,XX females.

PubMed

Pentinpuro, Raija Helena; Lähdesmäki, Raija Eliisa; Niinimaa, Ahti Olavi; Pesonen, Paula Ritva Orvokki; Alvesalo, Lassi Juhani

2014-11-01

Previous results regarding human sex chromosome aneuploidies have shown that the X and Y chromosomes affect tooth size and morphology. This study looked for the effect of sex chromosome deficiency on permanent tooth crown heights. The material, from the Finnish KVANTTI Research Project, consisted of 97 45,X females and 15 45,X/46,XX females. The controls were 32 sisters and 28 mothers of the 45,X females, eight sisters and two mothers of the 45,X/46,XX females and 35 female population controls. Crown heights of all the available teeth except third molars on both sides of the jaws were measured from panoramic radiographs with a digital calliper according to the defined procedure. The tooth crown heights were significantly smaller in the 45,X females than in the female population controls, except for the incisors and one canine in the maxilla, whereas the tooth crown heights of the 45,X/46,XX females were close to those of the normal control females. The differences between the 45,X and 45,X/46,XX females were statistically significant, excluding the upper incisor area and a few teeth in the mandible. The effect of the sex chromosome deficiency on permanent tooth crown height is due to the magnitude of lacking sex chromosome material. The present results regarding the 45,X females are parallel to previous findings in Turner patients regarding reduced mesiodistal and labiolingual dimensions and tooth crown heights in the permanent dentition.

76 FR 80970 - Records Schedules; Availability and Request for Comments

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-27

... studies working groups and other senior bodies, and substantive working papers. 11. Office of the Director... external web page material, and non-substantive working papers and drafts. Proposed for permanent retention... correspondence, staff-level working groups and committees, advisory program background information, non...

Shock wave energy dissipation behavior (SWED) in Network forming ionic liquids (NILs): A Molecular dynamics study

NASA Astrophysics Data System (ADS)

Guda Vishnu, Karthik; Strachan, Alejandro

2017-06-01

SWED materials play a crucial role in protecting both personnel and structures in close proximity to blasts or ballistic impact. Exposure to shock waves with intensities as low as 1 MPa can cause brain injury in personnel and, hence, it is extremely important to understand the mechanisms operating in SWED materials and help design improved formulations. Recent experimental studies show that NILs containing di-ammonium cations and citrate anions with glass transition temperatures (Tg) below room temperature exhibit shockwave absorption characteristics that outperform polyurea (PU), a benchmark SWED assessment material. The experimentalists further hypothesized that the increased SWED ability in NILs with longer side chains (in di-ammonium cation) is due to a permanent structural ordering and nano-scale segregation. We use molecular dynamics simulations with the Dreiding force field to study shock propagation mechanisms in NILs. Shock propagation mechanisms in these materials are explored by performing both Hugoniostat and large scale non-equilibrium molecular dynamics (NEMD) simulations at 300 K. The simulation results show that the NIL 5-6 (5 C atoms (back bone) and 6 C atoms (side chain)) attenuates shocks better than NIL 5-3 (3 C atoms (side chain) and higher Tg) and PMMA in agreement with experimental observation. The simulations show that under shock loading the structures lose long range order; we find no evidence of nano-segregation nor or permanent structural changes.

49 CFR 178.45 - Specification 3T seamless steel cylinder.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Section 178.45 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS SPECIFICATIONS... limits. Permanent closures formed by spinning are prohibited. (b) Material, steel. Only open hearth...

Clinical evaluation of a composite resin system with a dentin bonding agent for restoration of permanent posterior teeth: a 3-year study.

PubMed

Roberts, M W; Folio, J; Moffa, J P; Guckes, A D

1992-03-01

This study evaluated the clinical performance of a visible light-cured small particle bimodally filled hybrid condensable composite resin system that included a dentin bonding agent compared with an amalgam alloy in class II restorations of permanent teeth. A total of 108 restorations were placed in 34 patients. Fifty-three composite resin and 55 amalgam restorations were inserted. Each restoration was evaluated immediately after placement and then on an annual basis for a 3-year period using the Public Health Service (PHS) criteria. In addition, the Moffa-Lugassy scale was used to measure the loss of material on the occlusal surface of these materials. One hundred percent of the resin and amalgam restorations were evaluated, measured, and reasons for replacement were recorded over the 3-year period. There was no significant difference (p greater than 0.05) in the clinical performance of the composite resin and the amalgam when evaluated by the PHS criteria. Analyses of wear at each of the three annual recall periods did not reveal any significant difference (p greater than 0.05) between the two restorative materials when measured by the Moffa-Lugassy scale.

Permanent data recording in transparent materials by using a nanojoule-class pulse laser

NASA Astrophysics Data System (ADS)

Imai, Ryo; Shiozawa, Manabu; Watanabe, Takao; Umeda, Mariko; Mine, Toshiyuki; Kuretake, Satoshi; Watanabe, Koichi

2014-09-01

We investigated data recording for permanent data storage using an ultrafast pulse laser with nanojoule-class pulse energy and megahertz-class repetition rate in transparent materials, and driveless reading based on a simple imaging system. A transparent ceramics called Lumicera®, manufactured by Murata Mfg. Co., Ltd., was used as the recording medium. Lumicera® has a lower modification threshold and a higher recording sensitivity than those of silica glass, namely, the medium previously studied. Structural modification in Lumicera® occurs by light exposure for 10 μs, suggesting that Lumicera® has potential for a recording speed of over 100 kbps. Data recorded in Lumicera® resists heating for 2 h at 1000 °C and is expected to have a lifetime of over 300 million years. Moreover, the data recorded in Lumicera® was successfully read with a reading system based on a smart phone.

Permanent-plot procedures for silvicultural and yield research.

Treesearch

Robert O. Curtis; David D. Marshall

2005-01-01

This paper reviews purposes and procedures for establishing and maintaining permanent plots for silvicultural and yield research, sampling and plot design, common errors, and procedures for measuring and recording data. It is a revision and update of a 1983 publication. Although some details are specific to coastal Pacific Northwest conditions, most of the material is...

Electric machine

DOEpatents

El-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Reddy, Patel Bhageerath [Madison, WI

2012-07-17

An interior permanent magnet electric machine is disclosed. The interior permanent magnet electric machine comprises a rotor comprising a plurality of radially placed magnets each having a proximal end and a distal end, wherein each magnet comprises a plurality of magnetic segments and at least one magnetic segment towards the distal end comprises a high resistivity magnetic material.

Combined passive bearing element/generator motor

DOEpatents

Post, Richard F.

2000-01-01

An electric machine includes a cylindrical rotor made up of an array of permanent magnets that provide a N-pole magnetic field of even order (where N=4, 6, 8, etc.). This array of permanent magnets has bars of identical permanent magnets made of dipole elements where the bars are assembled in a circle. A stator inserted down the axis of the dipole field is made of two sets of windings that are electrically orthogonal to each other, where one set of windings provides stabilization of the stator and the other set of windings couples to the array of permanent magnets and acts as the windings of a generator/motor. The rotor and the stator are horizontally disposed, and the rotor is on the outside of said stator. The electric machine may also include two rings of ferromagnetic material. One of these rings would be located at each end of the rotor. Two levitator pole assemblies are attached to a support member that is external to the electric machine. These levitator pole assemblies interact attractively with the rings of ferromagnetic material to produce a levitating force upon the rotor.

Design of a Permanent-Magnet Zeeman Slower

NASA Astrophysics Data System (ADS)

Adler, Charles; Narducci, Frank; Sukenik, Charles; Mulholland, Jonathan; Goodale, Sarah

2006-05-01

During the past decade, low cost, flexible, and highly-polarized magnetic field sheet material has become available with field strengths useful for applications in modern atomic physics experiments. One advantage of using such material is that it can easily be cut to almost any desired shape without appreciable loss of field strength making it more versatile than ceramic magnets. We present the design of a Zeeman slower, made from such material, for cooling an atomic beam of neutral rubidium atoms and discuss results from an atomic beam trajectory simulation which indicates that the slower should perform well. We will also report on progress of a prototype permanent magnet Zeeman slower presently under construction in the laboratory.

Crystallinity as a tunable switch of poly(L-lactide) shape memory effects.

PubMed

Sobota, Michał; Jurczyk, Sebastian; Kwiecień, Michał; Smola-Dmochowska, Anna; Musioł, Marta; Domański, Marian; Janeczek, Henryk; Kawalec, Michał; Kurcok, Piotr

2017-02-01

Materials with shape memory effect (SME) have already been widely used in the medical field. The interesting part of this group is represented by double function materials. The bioresorption and SME ability are common in polyesters implants. The first information about vascular stent made of bioresorbable polyester with SME was published in 2000. However, there are not many investigations about SME control of elements in the aspect of material processing. In the present work, the ability to control the shape memory (SM) of bioresorbable and semicrystalline poly(L-lactide) (PLLA) is investigated. The studies are based on the unexpected effect of material orientation which was demonstrated even at low percentage deformation in crystallized mould injected material. The presented studies revealed that the different degrees of crystallinity obtained during processing might be a useful switch to create a tailored SME for a specific application. The prepared samples of variable morphology revealed a possibility to control the value of material stress during permanent shape recovery. The degree of shape recovery of the prepared samples was also controlable. The highest stress value observed during permanent shape recovery reached 10MPa for the sample annealed 60min at 115°C even when the sample was only deformed in 8%. The other significant aspect of this work is to present the problem of slow crystallization of the material during and after processing (cooling rate) as well as the possibility of negative SME change during the shelf life of the fabric. Copyright © 2016 Elsevier Ltd. All rights reserved.

Metal Amorphous Nanocomposite Soft Magnetic Material-Enabled High Power Density, Rare Earth Free Rotational Machines [Metal Amorphous Nanocomposite (MANC) Soft Magnetic Material (SMM) Enabled High Power Density, Rare Earth Free Rotational Machines

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

Simizu, Satoru; Ohodnicki, Paul R.; McHenry, Michael E.

Metal amorphous nanocomposites (MANCs) are promising soft magnetic materials (SMMs) for power electronic applications offering low power loss at high frequency and maintaining a relatively high flux density. While applications in certain motor designs have been recently modeled, their widespread application awaits scaled manufacturing of MANC materials and proliferation of new higher speed motor designs. A hybrid motor design based on permanent magnets and doubly salient stator and rotor is reported here to develop a compact (a factor of 10 smaller than currently possible in Si steels), high-speed (>1 kHz, electrical), high-power (>2.5 kW) motor by incorporating low loss (<10more » W/kg at 1 kHz) MANCs such as recently reported Fe-Ni-based alloys. A feature of this motor design is flux focusing from the permanent magnet allowing use of lower energy permanent magnet chosen from among non-rare earth containing compositions and attractive due to constraints posed by rare earth criticality. A 2-D finite element analysis model reported here indicates that a 2.5 kW hybrid motor may be built with a permanent magnet with a 0.4 T remanence at a rotor speed of 6000 rpm. At a magnetic switching frequency of 1.4 kHz, the core loss may be limited to <3 W by selecting an appropriate MANC SMM. The projected efficiency exceeds 96% not including power loss in the controller. Under full load conditions, the flux density distributions for the SMM stay predominantly <1.3 T, the saturation magnetization of optimized FeNi-based MANC alloys. As a result, the maximum demagnetizing field in the permanent magnet is less than 2.2 × 10 5 A/m sustainable, for example, with a high-grade hard ferrite magnet.« less

Metal Amorphous Nanocomposite Soft Magnetic Material-Enabled High Power Density, Rare Earth Free Rotational Machines [Metal Amorphous Nanocomposite (MANC) Soft Magnetic Material (SMM) Enabled High Power Density, Rare Earth Free Rotational Machines

DOE PAGES

Simizu, Satoru; Ohodnicki, Paul R.; McHenry, Michael E.

2018-02-27

Metal amorphous nanocomposites (MANCs) are promising soft magnetic materials (SMMs) for power electronic applications offering low power loss at high frequency and maintaining a relatively high flux density. While applications in certain motor designs have been recently modeled, their widespread application awaits scaled manufacturing of MANC materials and proliferation of new higher speed motor designs. A hybrid motor design based on permanent magnets and doubly salient stator and rotor is reported here to develop a compact (a factor of 10 smaller than currently possible in Si steels), high-speed (>1 kHz, electrical), high-power (>2.5 kW) motor by incorporating low loss (<10more » W/kg at 1 kHz) MANCs such as recently reported Fe-Ni-based alloys. A feature of this motor design is flux focusing from the permanent magnet allowing use of lower energy permanent magnet chosen from among non-rare earth containing compositions and attractive due to constraints posed by rare earth criticality. A 2-D finite element analysis model reported here indicates that a 2.5 kW hybrid motor may be built with a permanent magnet with a 0.4 T remanence at a rotor speed of 6000 rpm. At a magnetic switching frequency of 1.4 kHz, the core loss may be limited to <3 W by selecting an appropriate MANC SMM. The projected efficiency exceeds 96% not including power loss in the controller. Under full load conditions, the flux density distributions for the SMM stay predominantly <1.3 T, the saturation magnetization of optimized FeNi-based MANC alloys. As a result, the maximum demagnetizing field in the permanent magnet is less than 2.2 × 10 5 A/m sustainable, for example, with a high-grade hard ferrite magnet.« less

Investigating compression failure mechanisms in composite laminates with a transparent fiberglass-epoxy birefringent materials

NASA Technical Reports Server (NTRS)

Shuart, M. J.; Williams, J. G.

1984-01-01

The response and failure of a + or - 45s class laminate was studied by transparent fiberglass epoxy composite birefringent material. The birefringency property allows the laminate stress distribution to be observed during the test and also after the test if permanent residual stresses occur. The location of initial laminate failure and of the subsequent failure propagation are observed through its transparency characteristics. Experimental results are presented.

Electrostatic-Assisted Liquefaction of Porous Carbons

DOE PAGES

Li, Peipei; Schott, Jennifer A.; Zhang, Jinshui; ...

2017-10-10

Porous liquids are a newly developed porous material that combine unique fluidity with permanent porosity, which exhibit promising functionalities for a variety of applications. However, the apparent incompatibility between fluidity and permanent porosity makes the stabilization of porous nanoparticle with still empty pores in the dense liquid phase a significant challenging. For this study, by exploiting the electrostatic interaction between carbon networks and polymerized ionic liquids, we demonstrate that carbon-based porous nanoarchitectures can be well stabilized in liquids to afford permanent porosity, and thus opens up a new approach to prepare porous carbon liquids. Furthermore, we hope this facile synthesismore » strategy can be widely applicated to fabricate other types of porous liquids, such as those (e.g., carbon nitride, boron nitride, metal–organic frameworks, covalent organic frameworks etc.) also having the electrostatic interaction with polymerized ionic liquids, evidently advancing the development and understanding of porous liquids.« less

Covalent adaptable networks: smart, reconfigurable and responsive network systems.

PubMed

Kloxin, Christopher J; Bowman, Christopher N

2013-09-07

Covalently crosslinked materials, classically referred to as thermosets, represent a broad class of elastic materials that readily retain their shape and molecular architecture through covalent bonds that are ubiquitous throughout the network structure. These materials, in particular in their swollen gel state, have been widely used as stimuli responsive materials with their ability to change volume in response to changes in temperature, pH, or other solvent conditions and have also been used in shape memory applications. However, the existence of a permanent, unalterable shape and structure dictated by the covalently crosslinked structure has dramatically limited their abilities in this and many other areas. These materials are not generally reconfigurable, recyclable, reprocessable, and have limited ability to alter permanently their stress state, topography, topology, or structure. Recently, a new paradigm has been explored in crosslinked polymers - that of covalent adaptable networks (CANs) in which covalently crosslinked networks are formed such that triggerable, reversible chemical structures persist throughout the network. These reversible covalent bonds can be triggered through molecular triggers, light or other incident radiation, or temperature changes. Upon application of this stimulus, rather than causing a temporary shape change, the CAN structure responds by permanently adjusting its structure through either reversible addition/condensation or through reversible bond exchange mechanisms, either of which allow the material to essentially reequilibrate to its new state and condition. Here, we provide a tutorial review on these materials and their responsiveness to applied stimuli. In particular, we review the broad classification of these materials, the nature of the chemical bonds that enable the adaptable structure, how the properties of these materials depend on the reversible structure, and how the application of a stimulus causes these materials to alter their shape, topography, and properties.

Topology optimized and 3D printed polymer-bonded permanent magnets for a predefined external field

NASA Astrophysics Data System (ADS)

Huber, C.; Abert, C.; Bruckner, F.; Pfaff, C.; Kriwet, J.; Groenefeld, M.; Teliban, I.; Vogler, C.; Suess, D.

2017-08-01

Topology optimization offers great opportunities to design permanent magnetic systems that have specific external field characteristics. Additive manufacturing of polymer-bonded magnets with an end-user 3D printer can be used to manufacture permanent magnets with structures that had been difficult or impossible to manufacture previously. This work combines these two powerful methods to design and manufacture permanent magnetic systems with specific properties. The topology optimization framework is simple, fast, and accurate. It can also be used for the reverse engineering of permanent magnets in order to find the topology from field measurements. Furthermore, a magnetic system that generates a linear external field above the magnet is presented. With a volume constraint, the amount of magnetic material can be minimized without losing performance. Simulations and measurements of the printed systems show very good agreement.

Comparative evaluation of border molding, using two different techniques in maxillary edentulous arches - An in vivo study

PubMed Central

Yarapatineni, Rameshbabu; Vilekar, Abhishek; Kumar, J Phani; Kumar, G Ajay; Aravind, Prasad; Kumar, P Anil

2013-01-01

Background: This study was undertaken to compare the retention between sectional border molding using low fusing greenstick compound and single step border molding using condensation silicone (putty) impression material in three stages- A. Immediately following border molding, B. After final impression and C. With the finished permanent denture base. Materials & Methods: In this study evaluation of retentive values of sectional border molding (Group I) (custom impression trays border molded with green stick compound ) and single step border molding (Group II) ( border molding with condensation silicone (putty) impression material ). In both techniques definitive wash impression were made with light body condensation silicone and permanent denture base with heat cure polymerization resin. Results: Group II was significantly higher (mean=8011.43) than Group I (mean=5777.43) in test-A. The t-value (1.5883) infers that there was significant difference between Group I and Group II (p =0.15). Group I was significantly higher (mean=6718.57) than Group II (mean=5224.29) in test -B. The t-value (1.6909) infers that there was significant difference between Group I and Group II (p=0.17). Group II was higher (mean=4025.14) than Group I (mean=3835.07) in test -C. The t-value was 0.1239. But it was found to be statistically insignificant (p=0.005). Conclusion: Within the limitation of this clinical study border molding custom tray with low fusing green stick compound provided similar retention as compared to custom impression tray with condensation silicone in permanent denture base. How to cite this article: Yarapatineni R, Vilekar A, Kumar JP, Kumar GA, Aravind P, Kumar PA. Comparative evaluation of border molding, using two different techniques in maxillary edentulous arches - An in vivo study. J Int Oral Health 2013; 5(6):82-7 . PMID:24453450

Intrapulpal Thermal Changes during Setting Reaction of Glass Carbomer® Using Thermocure Lamp.

PubMed

Kahvecioglu, Firdevs; Tosun, Gül; Ülker, Hayriye Esra

2016-01-01

Objectives . To measure the temperature increase induced during thermocure lamp setting reaction of glass carbomer and to compare it with those induced by visible light curing of a resin-modified glass ionomer and a polyacid-modified composite resin in primary and permanent teeth. Materials and Methods . Nonretentive class I cavities were prepared in extracted primary and permanent molars. Glass carbomer (GC) was placed in the cavity and set at 60°C for 60 sn using a special thermocure lamp. Resin-modified glass ionomer (RMGIC) and polyacid-modified composite resin (PMCR) were placed in the cavities and polymerized with an LED curing unit. Temperature increases during setting reactions were measured with a J-type thermocouple wire connected to a data logger. Data were examined using two-way analysis of variance and Tukey's honestly significant difference tests. Results . The use of GC resulted in temperature changes of 5.17 ± 0.92°C and 5.32 ± 0.90°C in primary and permanent teeth, respectively ( p > 0.05). Temperature increases were greatest in the GC group, differing significantly from those in the PMCR group ( p < 0.05). Conclusion . Temperature increases during polymerization and setting reactions of the materials were below the critical value in all groups. No difference was observed between primary and permanent teeth, regardless of the material used.

Humans permanently occupied the Andean highlands by at least 7 ka

PubMed Central

Stefanescu, Ioana C.; Garcia-Putnam, Alexander; Aldenderfer, Mark S.; Clementz, Mark T.; Murphy, Melissa S.; Llave, Carlos Viviano; Watson, James T.

2017-01-01

High-elevation environments above 2500 metres above sea level (m.a.s.l.) were among the planet's last frontiers of human colonization. Research on the speed and tempo of this colonization process is active and holds implications for understanding rates of genetic, physiological and cultural adaptation in our species. Permanent occupation of high-elevation environments in the Andes Mountains of South America tentatively began with hunter–gatherers around 9 ka according to current archaeological estimates, though the timing is currently debated. Recent observations on the archaeological site of Soro Mik'aya Patjxa (8.0–6.5 ka), located at 3800 m.a.s.l. in the Andean Altiplano, offer an opportunity to independently test hypotheses for early permanent use of the region. This study observes low oxygen (δ18O) and high carbon (δ13C) isotope values in human bone, long travel distances to low-elevation zones, variable age and sex structure in the human population and an absence of non-local lithic materials. These independent lines of evidence converge to support a model of permanent occupation of high elevations and refute logistical and seasonal use models. The results constitute the strongest empirical support to date for permanent human occupation of the Andean highlands by hunter–gatherers before 7 ka. PMID:28680685

Nonmetric traits of permanent posterior teeth in Kerala population: A forensic overview

PubMed Central

Baby, Tibin K; Sunil, S; Babu, Sharlene Sara

2017-01-01

Introduction: Dental morphology is a highly heritable characteristic which is stable with time and has a fairly high state of preservation. Nonmetric dental traits have crucial role in ethnic classifications of a population that helps in forensic racial identification purposes. Aims and Objectives: To determine the frequency and variability of possible nonmetric tooth traits using extracted permanent posterior teeth from Kerala population for discerning racial ethnicity. Materials and Methods: This qualitative, cross-sectional study was carried out using 1743 extracted intact permanent posterior teeth collected from different dental clinics situated all over Kerala. Results: The more common features on premolars were multiple lingual cusps (31.21%), distal accessary ridges (16.28%) and Tom's root (17.9%). In upper first molars, Carabelli trait expression was 17.78% and other common features included metaconulo, cusp 5 and enamel extensions. Conclusion: Posterior tooth traits had variable expression in the study population. Low prevalence rate of Carabelli trait in this study is characteristic of Asian population. This research explored new elements of invaluable tooth traits values to understand racial ethnicity of Kerala population. PMID:28932045

Targeting a portion of central European spider diversity for permanent preservation.

PubMed

Candek, Klemen; Gregorič, Matjaž; Kostanjšek, Rok; Frick, Holger; Kropf, Christian; Kuntner, Matjaž

2013-01-01

Given the limited success of past and current conservation efforts, an alternative approach is to preserve tissues and genomes of targeted organisms in cryobanks to make them accessible for future generations. Our pilot preservation project aimed to obtain, expertly identify, and permanently preserve a quarter of the known spider species diversity shared between Slovenia and Switzerland, estimated at 275 species. We here report on the faunistic part of this project, which resulted in 324 species (227 in Slovenia, 143 in Switzerland) for which identification was reasonably established. This material is now preserved in cryobanks, is being processed for DNA barcoding, and is available for genomic studies.

Amorphous and Nanocomposite Materials for Energy-Efficient Electric Motors

NASA Astrophysics Data System (ADS)

Silveyra, Josefina M.; Xu, Patricia; Keylin, Vladimir; DeGeorge, Vincent; Leary, Alex; McHenry, Michael E.

2016-01-01

We explore amorphous soft-magnetic alloys as candidates for electric motor applications. The Co-rich system combines the benefits of low hysteretic and eddy-current losses while exhibiting negligible magnetostriction and robust mechanical properties. The amorphous precursors can be devitrified to form nanocomposite magnets. The superior characteristics of these materials offer the advantages of ease of handling in the manufacturing processing and low iron losses during motor operation. Co-rich amorphous ribbons were laser-cut to build a stator for a small demonstrator permanent-magnet machine. The motor was tested up to ~30,000 rpm. Finite-element analyses proved that the iron losses of the Co-rich amorphous stator were ~80% smaller than for a Si steel stator in the same motor, at 18,000 rpm (equivalent to an electric frequency of 2.1 kHz). These low-loss soft magnets have great potential for application in highly efficient high-speed electric machines, leading to size reduction as well as reduction or replacement of rare earths in permanent-magnet motors. More studies evaluating further processing techniques for amorphous and nanocomposite materials are needed.

Summit on the beneficial use of dredged materials : turning a surplus material into a commodity of value.

DOT National Transportation Integrated Search

2014-07-01

Dredged material management options for commercial ports, particularly those involving permanent or long-term placement facilities, are : diminishing. Many existing placement facilities serving these ports are at, or near capacity, and high costs, pl...

Development of Fully-Integrated Micromagnetic Actuator Technologies

DTIC Science & Technology

2015-07-13

nonexistent because of certain design and fabrication challenges— primarily the inability to integrate high-performance, permanent - magnet ( magnetically ... efficiency necessary for certain applications. To enable the development of high-performance magnetic actuator technologies, the original research plan...developed permanent - magnet materials in more complex microfabrication process flows Objective 2: Design, model, and optimize a novel multi- magnet

Existence as a Psychological Problem: Object Permanence in Adults and Preschool Children.

ERIC Educational Resources Information Center

Subbotskii, E. V.

1991-01-01

Examines perceptions of adults compared with preschool children in assuming object permanence or discontinuity of existence when an object is removed from their immediate perceptual field. Results showed that a belief in the possibility of the discontinuity of material objects is not unique to the minds of preschool children but can also be…

Characterization of Crew Refuse Returned from Shuttle Missions with Permanent Gas, Volatile Organic Compound, and Microbial Analyses

NASA Astrophysics Data System (ADS)

Peterson, B.; Hummerick, M.; Roberts, M.; Krummins, V.; Kish, A.; Garland, J.; Maxwell, S.; Mills, A.

In addition to the mass and energy costs associated with bioregenerative systems for advanced life support, the storage and processing of waste on spacecraft requires both atmospheric and biological management. Risks to crew health may arise from the presence of potential human pathogens in waste or from decay processes during waste storage and/or processing. This study reports on the permanent gas, trace volatile organic and microbiological analyses of crew refuse returned from shuttle missions STS-105, 109 and 110. The research objective is to characterize the biological stability of the waste stream, to assess the risks associated with its storage, and to provide baseline measures for the evaluation of waste processing technologies. Microbiological samples were collected from packaging material, food waste, bathroom waste, and bulk liquid collected from the volume F waste container. The number of culturable bacteria and total bacteria were determined by plating on R2A media and by Acridine Orange direct count, respectively. Samples of the trash were analyzed for the presence of fecal and total coliforms and other human-associated bacteria. Dry and ash weights were determined to estimate both water and organic content of the materials. The aerobic and anaerobic bio-stability of stored waste was determined by on-line monitoring of CO2 and by laboratory analysis of off-gas samples for hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA method TO15 with gas chromatography/mass spectrometry and by gas chromatography with selective detectors . This study establishes a baseline measure of waste composition, labile organics, and microbial load for this material.

The Relation Between Dermatoglyphics And Mesiodistal Width Of The Deciduous Second Molar And Permanent First Molar

PubMed Central

Kumar, Vinod; Adusumilli, Hamsini; Reddy, KM Parveen; Kumar, NH Praveen

2017-01-01

Introduction Dermatoglyphics is one of the important diagnostic tools used in the recent days for identification of an individual. Dermatoglyphics is the study of type of patterns present on digits, palms and foot. The mesiodistal diameter of the tooth is an important factor which reveals the tooth-bone discrepancy. Deciduous second molar and permanent first molar exhibit least degree of variation. Both the dermal ridges and the enamel layer of the tooth originate from ectodermal layer and during the same period of intrauterine life. Aim To determine and compare the dermatoglyphics with the mesiodistal width of the deciduous second molar and permanent first molar. Materials and Methods A sample of 120 child ranaged between 6-12 years were included in the study whose digital and palmer traits were recorded using ink method and the mesiodistal widths of the deciduous second molar and permanent first molar were recorded using a vernier caliper. The data was subjected to statistical analysis using unpaired t test. Results The ‘ATD’ angle was found in the range of 40°-50°. The loop patterns were more common followed by whorls and arch patterns. Girls expressed a greater mesiodistal diameter of deciduous second molar than boys. No significant correlation was found in between the dermatoglyphics and tooth size. Conclusion There was no significant correlation between the finger print patterns, ‘ATD’ angle and the mesiodistal diameter of the deciduous second molar and the permanent first molar. PMID:28969275

Feasibility of low-cost magnetic rail designs by integrating ferrite magnets and NdFeB magnets for HTS Maglev systems

NASA Astrophysics Data System (ADS)

Sun, R. X.; Deng, Z. G.; Gou, Y. F.; Li, Y. J.; Zheng, J.; Wang, S. Y.; Wang, J. S.

2015-09-01

Permanent magnet guideway (PMG) is an indispensable part of high temperature superconducting (HTS) Maglev systems. Present PMGs are made of NdFeB magnets with excellent performance and cost much. As another permanent magnet material, the ferrite magnet is weak at magnetic energy product and coercive force, but inexpensive. So, it is a possible way to integrate the ferrite and NdFeB magnets for cutting down the cost of present PMGs. In the paper, the equivalent on magnetic field intensity between ferrite magnets and NdFeB magnets was evaluated by finite element simulation. According to the calculation results, the magnetic field of the PMG integrating ferrite magnets and NdFeB magnets can be increased remarkably comparing with the pure ferrite PMG. It indicates that low-cost PMG designs by integrating the two permanent magnet materials are feasible for the practical HTS Maglev system.

Improving Rutting Resistance of Pavement Structures Using Geosynthetics: An Overview

PubMed Central

Karim, Mohamed Rehan; Khodaii, Ali; Almasi, Mohammad Hadi

2014-01-01

A pavement structure consists of several layers for the primary purpose of transmitting and distributing traffic loads to the subgrade. Rutting is one form of pavement distresses that may influence the performance of road pavements. Geosynthetics is one type of synthetic materials utilized for improving the performance of pavements against rutting. Various studies have been conducted on using different geosynthetic materials in pavement structures by different researchers. One of the practices is a reinforcing material in asphalt pavements. This paper intends to present and discuss the discoveries from some of the studies on utilizing geosynthetics in flexible pavements as reinforcement against permanent deformation (rutting). PMID:24526919

Improving rutting resistance of pavement structures using geosynthetics: an overview.

PubMed

Mirzapour Mounes, Sina; Karim, Mohamed Rehan; Khodaii, Ali; Almasi, Mohammad Hadi

2014-01-01

A pavement structure consists of several layers for the primary purpose of transmitting and distributing traffic loads to the subgrade. Rutting is one form of pavement distresses that may influence the performance of road pavements. Geosynthetics is one type of synthetic materials utilized for improving the performance of pavements against rutting. Various studies have been conducted on using different geosynthetic materials in pavement structures by different researchers. One of the practices is a reinforcing material in asphalt pavements. This paper intends to present and discuss the discoveries from some of the studies on utilizing geosynthetics in flexible pavements as reinforcement against permanent deformation (rutting).

Evaluation of Permanent Deformation of CRM-Reinforced SMA and Its Correlation with Dynamic Stiffness and Dynamic Creep

PubMed Central

Mashaan, Nuha Salim; Karim, Mohamed Rehan

2013-01-01

Today, rapid economic and industrial growth generates increasing amounts of waste materials such as waste tyre rubber. Attempts to inspire a green technology which is more environmentally friendly that can produce economic value are a major consideration in the utilization of waste materials. The aim of this study is to evaluate the effect of waste tyre rubber (crumb rubber modifier (CRM)), in stone mastic asphalt (SMA 20) performance. The virgin bitumen (80/100) penetration grade was used, modified with crumb rubber at four different modification levels, namely, 6%, 12%, 16%, and 20% by weight of the bitumen. The testing undertaken on the asphalt mix comprises the indirect tensile (dynamic stiffness), dynamic creep, and wheel tracking tests. By the experimentation, the appropriate amount of CRM was found to be 16% by weight of bitumen. The results show that the addition of CRM into the mixture has an obvious significant effect on the performance properties of SMA which could improve the mixture's resistance against permanent deformation. Further, higher correlation coefficient was obtained between the rut depth and permanent strain as compared to resilient modulus; thus dynamic creep test might be a more reliable test in evaluating the rut resistance of asphalt mixture. PMID:24302883

Evaluation of permanent deformation of CRM-reinforced SMA and its correlation with dynamic stiffness and dynamic creep.

PubMed

Mashaan, Nuha Salim; Karim, Mohamed Rehan

2013-01-01

Today, rapid economic and industrial growth generates increasing amounts of waste materials such as waste tyre rubber. Attempts to inspire a green technology which is more environmentally friendly that can produce economic value are a major consideration in the utilization of waste materials. The aim of this study is to evaluate the effect of waste tyre rubber (crumb rubber modifier (CRM)), in stone mastic asphalt (SMA 20) performance. The virgin bitumen (80/100) penetration grade was used, modified with crumb rubber at four different modification levels, namely, 6%, 12%, 16%, and 20% by weight of the bitumen. The testing undertaken on the asphalt mix comprises the indirect tensile (dynamic stiffness), dynamic creep, and wheel tracking tests. By the experimentation, the appropriate amount of CRM was found to be 16% by weight of bitumen. The results show that the addition of CRM into the mixture has an obvious significant effect on the performance properties of SMA which could improve the mixture's resistance against permanent deformation. Further, higher correlation coefficient was obtained between the rut depth and permanent strain as compared to resilient modulus; thus dynamic creep test might be a more reliable test in evaluating the rut resistance of asphalt mixture.

Environmental Factors Affecting the Permanence of Library Materials

ERIC Educational Resources Information Center

Wessel, Carl J.

1970-01-01

Reviews pertinent evidence relating to deterioration originating with air pollution, heat, humidity, light, and biological agents; and suggests how librarians may lengthen the useful life of library materials through environmental controls. (Author/JS)

Assessment of wrought ASTM F1058 cobalt alloy properties for permanent surgical implants.

PubMed

Clerc, C O; Jedwab, M R; Mayer, D W; Thompson, P J; Stinson, J S

1997-01-01

The behavior of the ASTM F1058 wrought cobalt-chromium-nickel-molybdenum-iron alloy (commonly referred to as Elgiloy or Phynox) is evaluated in terms of mechanical properties, magnetic resonance imaging, corrosion resistance, and biocompatibility. The data found in the literature, the experimental corrosion and biocompatibility results presented in this article, and its long track record as an implant material demonstrate that the cobalt superalloy is an appropriate material for permanent surgical implants that require high yield strength and fatigue resistance combined with high elastic modulus, and that it can be safely imaged with magnetic resonance.

The foundations of object permanence: does perceived cohesion determine infants' appreciation of the continuous existence of material objects?

PubMed

Cacchione, Trix

2013-09-01

One of the most fundamental achievements in infants' cognitive development is their appreciation that material objects exist permanently in space and time. Recent findings suggest that infants fail to identify fragmented material objects as continuously existing items. Four experiments assessed 8-12-month-old infants' ability to further represent an object that was fragmented into two or more parts. Results suggest that infants successfully trace the spatiotemporal displacement of fragmented objects, but that their processing of size/quantity-related property information may be affected. This suggests that, contrary to recent claims, 8- to 12-month-old infants can and do appreciate the continuity of fragmented objects. Copyright © 2013 Elsevier B.V. All rights reserved.

A Study to Improve the Brazilian Air Force’s Material Management System

DTIC Science & Technology

1991-12-01

of Technology, in June 1990. Permanent Address: Base A6rea de Sio Paulo Instituto de Logistica da Aerongutica 07181 Guarulhos Sio Paulo Brazil 160 Vita...orders instead of more frequent smaller ones, and transportation from vendor to depot, which includes international fees in most cases, would be...optimized by the same reason. The transportation from depots to final users would not be affected, since only changes of depots and changes of material

Development and evaluation of thermoplastic street maintenance material

NASA Technical Reports Server (NTRS)

Siemens, W. D.

1973-01-01

An all-weather permanent street patching material was investigated for flexible and rigid pavements. The economic, operational, and material requirements are discussed along with the results of field tests with various mixtures of EVA resins and asphalt. Cost analyses for thermoplastic patching methods are included.

The case for Mars: Concept development for a Mars research station

NASA Technical Reports Server (NTRS)

Welch, S. M. (Editor); Stoker, C. R. (Editor)

1986-01-01

A program to establish a permanent scientific research base on Mars is described. A Mars base as the much needed long-term focus for the space program is presented. A permanent base was chosen rather than the more conventional concept of a series of individual missions to different sites because the permanent base offers much greater scientific return plus greater crew safety and the potential for eventual growth into a settlement. The Mars base will strive for self-sufficiency and autonomy from Earth. Martian resources will be used to provide life support materials and consumables. The Martian atmosphere will provide a convenient source of volatiles: CO2, N2, and water. Rocket propellant (for returning vehicles), fuels, breathable air, and fertilizers will be manufactured from Mars air. Food will be grown on Mars using Martian materials as plant nutrients. A permanent human presence will be maintained on Mars beginning with the first manned landing via a strategy of crew overlap. This permanent presence will ensure safety and reliability of systems through continuous tending, maintenance, and expansion of the base's equipment and systems. A permanent base will allow the development of a substantial facility on Mars for the same cost (in terms of Earth departure mass) as a series of temporary camps. A base equipped with surface rovers, airplanes, and the ability to manufacture consumables and return propellant will allow far more extensive planetary exploration over a given period of years than would approaches featuring a series of short exploration missions such as the Apollo Moon program.

The case for Mars: Concept development for a Mars research station

NASA Astrophysics Data System (ADS)

Welch, S. M.; Stoker, C. R.

1986-04-01

A program to establish a permanent scientific research base on Mars is described. A Mars base as the much needed long-term focus for the space program is presented. A permanent base was chosen rather than the more conventional concept of a series of individual missions to different sites because the permanent base offers much greater scientific return plus greater crew safety and the potential for eventual growth into a settlement. The Mars base will strive for self-sufficiency and autonomy from Earth. Martian resources will be used to provide life support materials and consumables. The Martian atmosphere will provide a convenient source of volatiles: CO2, N2, and water. Rocket propellant (for returning vehicles), fuels, breathable air, and fertilizers will be manufactured from Mars air. Food will be grown on Mars using Martian materials as plant nutrients. A permanent human presence will be maintained on Mars beginning with the first manned landing via a strategy of crew overlap. This permanent presence will ensure safety and reliability of systems through continuous tending, maintenance, and expansion of the base's equipment and systems. A permanent base will allow the development of a substantial facility on Mars for the same cost (in terms of Earth departure mass) as a series of temporary camps. A base equipped with surface rovers, airplanes, and the ability to manufacture consumables and return propellant will allow far more extensive planetary exploration over a given period of years than would approaches featuring a series of short exploration missions such as the Apollo Moon program.

Permanent magnet design for magnetic heat pumps using total cost minimization

NASA Astrophysics Data System (ADS)

Teyber, R.; Trevizoli, P. V.; Christiaanse, T. V.; Govindappa, P.; Niknia, I.; Rowe, A.

2017-11-01

The active magnetic regenerator (AMR) is an attractive technology for efficient heat pumps and cooling systems. The costs associated with a permanent magnet for near room temperature applications are a central issue which must be solved for broad market implementation. To address this problem, we present a permanent magnet topology optimization to minimize the total cost of cooling using a thermoeconomic cost-rate balance coupled with an AMR model. A genetic algorithm identifies cost-minimizing magnet topologies. For a fixed temperature span of 15 K and 4.2 kg of gadolinium, the optimal magnet configuration provides 3.3 kW of cooling power with a second law efficiency (ηII) of 0.33 using 16.3 kg of permanent magnet material.

Thermal highly porous insulation materials made of mineral raw materials

NASA Astrophysics Data System (ADS)

Mestnikov, A.

2015-01-01

The main objective of the study is to create insulating foam based on modified mineral binders with rapid hardening. The results of experimental studies of the composition and properties of insulating foam on the basis of rapidly hardening Portland cement (PC) and gypsum binder composite are presented in the article. The article proposes technological methods of production of insulating foamed concrete and its placement to the permanent shuttering wall enclosures in monolithic-frame construction and individual energy-efficient residential buildings, thus reducing foam shrinkage and improving crack-resistance.

The Opinions of Primary School Teachers' Candidates towards Material Preparation and Usage

ERIC Educational Resources Information Center

Genc, Zeynep

2016-01-01

Instruction materials help students to acquire more memorable information. Instruction materials have an important effect on providing more permanent and simple way of learning in every step of education. Instruction materials are the most frequently used by primary school teachers. Primary school teachers should support their lectures with…

Antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles.

PubMed

Ginjupalli, Kishore; Alla, Rama Krishna; Tellapragada, Chaitanya; Gupta, Lokendra; Upadhya Perampalli, Nagaraja

2016-06-01

Conventional spray and the immersion disinfection of irreversible hydrocolloid impression materials may lead to dimensional changes. The purpose of this in vitro study was to investigate the antimicrobial activity and properties of irreversible hydrocolloid impression materials incorporated with silver nanoparticles. The antimicrobial activity and properties of 2 commercially available irreversible hydrocolloid impression materials were evaluated after incorporating varying concentrations of silver nanoparticles. Antimicrobial activity was determined using the disk diffusion method. The gel strength, permanent deformation, flow, and gelation time were measured according to American Dental Association specification #18. Analysis of variance was used to identify the significant differences within and across the groups (α=.05). Adding silver nanoparticles to irreversible hydrocolloid impression materials resulted in superior antimicrobial activity without adversely affecting their properties. Adding silver nanoparticles to Zelgan significantly increased the gel strength compared with the control group, except at 5 wt%. However, the gel strength of Tropicalgin was unaffected except at 5 wt%. An increase in the permanent deformation was found with the incorporation of silver nanoparticles in both Zelgan and Tropicalgin. The flow of Zelgan increased with the incorporation of silver nanoparticles, whereas a decrease in the flow of Tropicalgin was observed at 1 wt% and 2 wt%. An increase in the gelation time of both Zelgan and Tropicalgin was observed with the incorporation of silver nanoparticles. Based on this in vitro study, silver nanoparticles can be incorporated into irreversible hydrocolloid impression materials as antimicrobial agents without adversely affecting their properties. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Models And Experiments Of Laminar Diffusion Flames In Non-Uniform Magnetic Fields

NASA Technical Reports Server (NTRS)

Baker, J.; Varagani, R.; Saito, K.

2003-01-01

Non-uniform magnetic fields affect laminar diffusion flames as a result of the paramagnetic and diamagnetic properties of the products and reactants. Paramagnetism is the weak attraction to a magnetic field a material exhibits as a result of permanent magnetic dipole moments in the atoms of the material. Diamagnetism is the weak repulsion to a magnetic field exhibited by a material due to the lack of permanent magnetic dipole moments in the atoms of a material. The forces associated with paramagnetic and diamagnetism are several orders of magnitude less than the forces associated with the more familiar ferromagnetism. A typical example of a paramagnetic gas is oxygen while hydrocarbon fuels and products of combustion are almost always diamagnetic. The fact that magnets can affect flame behavior has been recognized for more than one hundred years. Early speculation was that such behavior was due to the magnetic interaction with the ionized gases associated with a flame. Using a scaling analysis, it was later shown that for laminar diffusion flames the magnetic field/ionized gas interaction was insignificant to the paramagnetic and diamagnetic influences. In this effort, the focus has been on examining laminar diffusion slot flames in the presence of non-uniform upward decreasing magnetic fields produced using permanent magnets. The principal reason for choosing slot flames was mathematical models of such flames show an explicit dependence on gravitational body forces, in the buoyancy-controlled regime, and an applied magnetic field would also impose a body force. In addition, the behavior of such flames was more easily visualized while maintaining the symmetry of the two-dimensional problem whereas it would have been impossible to obtain a symmetric magnetic field around a circular flame and still visually record the flame height and shape along the burner axis. The motivation for choosing permanent magnets to produce the magnetic fields was the assumption that space-related technologies based on the knowledge gained during this investigation would more likely involve permanent magnets as opposed to electromagnets. While no analysis has been done here to quantify the impact that an electric field, associated with an electromagnetic, would have relative to the paramagnetic and diamagnetic interactions, by using permanent magnets this potential effect was completely eliminated and thus paramagnetic and diamagnetic effects were isolated.

14 CFR 77.13 - Applicability.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SAFE... temporary construction or alteration, including equipment or materials used and any permanent or temporary..., including appurtenances, or lateral dimensions, including equipment or material used therein. ...

14 CFR 77.13 - Applicability.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIRSPACE SAFE... temporary construction or alteration, including equipment or materials used and any permanent or temporary..., including appurtenances, or lateral dimensions, including equipment or material used therein. ...

Permanent Closure of MFC Biodiesel Underground Storage Tank 99ANL00013

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

Kerry L. Nisson

2012-10-01

This closure package documents the site assessment and permanent closure of the Materials and Fuels Complex biodiesel underground storage tank 99ANL00013 in accordance with the regulatory requirements established in 40 CFR 280.71, “Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks: Out-of-Service UST Systems and Closure.”

A clinical trial to evaluate the retention of a silver cermet-ionomer cement used as a fissure sealant.

PubMed

Mills, R W; Ball, I A

1993-01-01

A randomized clinical trial was under-taken to compare the retention of a silver cermet-ionomer cement, Ketac Silver, with a conventional, autopolymerizing BIS-GMA resin sealant, Delton, using matched pairs of fissure sites within each subject's mouth. One hundred twenty matched contralateral pairs of fissure sites in first and second permanent molars of 53 school children were sealed with the two materials. The choice of site and material was selected at random. The ages of the children ranged from five to 16 years; first permanent molars were sealed in the five- to 10-year age group, and second permanent molars in the 11- to 16-year age group. Sealants were assessed as present, partly present, or absent at 6, 12, and 24 months. The number of pairs of sites available for reassessment declined from 102 at six months to 59 at 24 months as patients were lost to the study. Retention rates were higher for the Ketac Silver sealants at all three inspection intervals (P < 0.01): 93% compared with 74% at six months, 81% compared with 65% at 12 months, and 83% compared with 58% at 24 months. When analyzed according to age range, the difference between the retention rates was statistically significant in the five- to 10-year-olds but not significant in the 11- to 16-year-olds. The conclusion reached in this study was that cermet cement was better retained than conventional resin sealants in younger children.

Comfort and Content: Considerations for Informal Science Professional Development

ERIC Educational Resources Information Center

Holliday, Gary M.; Lederman, Norman G.; Lederman, Judith S.

2014-01-01

This study looked at a life science course that was offered at and taught by education staff of a large informal science institution (ISI) located in the Midwest. The curriculum, materials, and agendas for the course were developed by education staff and complemented a permanent life science exhibition. The researcher developed a content test…

Association between Chewing Side Preference and Dental Caries among Deciduous, Mixed and Permanent Dentition

PubMed Central

Sharma, Reena; Kashyap, Nilotpol; Prajapati, Deepesh; Kappadi, Damodar; Wadhwa, Saakshe; Gandotra, Shina; Yadav, Poonam

2016-01-01

Introduction Chewing Side Preference (CSP) is said to occur when mastication is recognized exclusively/consistently or predominantly on the same side of the jaw. It can be assessed by using the direct method - visual observation and indirect methods by electric programs, such as cinematography, kinetography and computerized electromyography. Aim The present study was aimed at evaluating the prevalence of CSP in deciduous, mixed and permanent dentitions and relating its association with dental caries. Materials and Methods In a cross-sectional observational study, 240 school going children aged 3 to 18years were randomly allocated to three experimental groups according to the deciduous dentition, mixed dentition and permanent dentition period. The existence of a CSP was determined using a direct method by asking the children to chew on a piece of gum (trident sugarless). The Mann Whitney U-test was used to compare the CSP and also among the boys and girls. The Spearman’s Correlation Coefficient was used to correlate CSP and dental caries among the three study groups and also among the groups. Results CSP was observed in 69%, 83% and 76% of children with primary, mixed and permanent dentition respectively (p>0.05). There was no statistically significant association between the presence of CSP and dental caries among the three study groups. Conclusion There was a weak or no correlation between gender and distribution of CSP and between presence of CSP and dental caries. PMID:27790569

14 CFR 77.5 - Kinds of objects affected.

Code of Federal Regulations, 2010 CFR

2010-01-01

....5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED..., including equipment or materials used therein, and apparatus of a permanent or temporary character; and (b... appurtenances), or lateral dimensions, including equipment or materials used therein. ...

14 CFR 77.5 - Kinds of objects affected.

Code of Federal Regulations, 2011 CFR

2011-01-01

....5 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED... or alteration, including equipment or materials used therein, and apparatus of a permanent or... height (including appurtenances), or lateral dimensions, including equipment or materials used therein. ...

Permanent molar pulpotomy with a new endodontic cement: A case series

PubMed Central

Asgary, Saeed; Ehsani, Sara

2009-01-01

The aim of this case series was to determine the clinical and radiographic success rate of pulpotomy, with new endodontic cement (NEC), in human mature permanent molar teeth. Twelve molars with established irreversible pulpitis were selected from patients 14 – 62 years old. The selection criteria included carious pulp exposure with a positive history of lingering pain. After isolation, caries removal, and pulp exposure, pulpotomy with NEC was performed and a permanent restoration was immediately placed. At the first recall (+1 day) no patients reported postoperative pain. One wisdom tooth had been extracted after two months because of failure in coronal restoration. Eleven patients were available for the second recall, with a mean time of 15.8 months. Clinical and radiographic examination revealed that all teeth were functional and free of signs and symptoms. Histological examination of the extracted teeth revealed complete dentin bridge formation and a normal pulp. Although the results favored the use of NEC, more studies with larger samples and a longer recall period were suggested, to justify the use of this novel material for treatment of irreversible pulpitis in human permanent molar teeth. PMID:20379438

Targeting a portion of central European spider diversity for permanent preservation

PubMed Central

2013-01-01

Abstract Given the limited success of past and current conservation efforts, an alternative approach is to preserve tissues and genomes of targeted organisms in cryobanks to make them accessible for future generations. Our pilot preservation project aimed to obtain, expertly identify, and permanently preserve a quarter of the known spider species diversity shared between Slovenia and Switzerland, estimated at 275 species. We here report on the faunistic part of this project, which resulted in 324 species (227 in Slovenia, 143 in Switzerland) for which identification was reasonably established. This material is now preserved in cryobanks, is being processed for DNA barcoding, and is available for genomic studies. PMID:24723774

CCL3 and CXCL12 production in vitro by dental pulp fibroblasts from permanent and deciduous teeth stimulated by Porphyromonas gingivalis LPS

PubMed Central

SIPERT, Carla Renata; MORANDINI, Ana Carolina de Faria; MODENA, Karin Cristina da Silva; DIONÍSIO, Thiago José; MACHADO, Maria Aparecida Andrade Moreira; de OLIVEIRA, Sandra Helena Penha; CAMPANELLI, Ana Paula; SANTOS, Carlos Ferreira

2013-01-01

Objective: The aim of this study was to compare the production of the chemokines CCL3 and CXCL12 by cultured dental pulp fibroblasts from permanent (PDPF) and deciduous (DDPF) teeth under stimulation by Porphyromonas gingivalis LPS (PgLPS). Material and Methods: Primary culture of fibroblasts from permanent (n=3) and deciduous (n=2) teeth were established using an explant technique. After the fourth passage, fibroblasts were stimulated by increasing concentrations of PgLPS (0 - 10 µg/mL) at 1, 6 and 24 h. The cells were tested for viability through MTT assay, and production of the chemokines CCL3 and CXCL12 was determined through ELISA. Comparisons among samples were performed using One-way ANOVA for MTT assay and Two-way ANOVA for ELISA results. Results: Cell viability was not affected by the antigen after 24 h of stimulation. PgLPS induced the production of CCL3 by dental pulp fibroblasts at similar levels for both permanent and deciduous pulp fibroblasts. Production of CXCL12, however, was significantly higher for PDPF than DDPF at 1 and 6 h. PgLPS, in turn, downregulated the production of CXCL12 by PDPF but not by DDPF. Conclusion: These data suggest that dental pulp fibroblasts from permanent and deciduous teeth may present a differential behavior under PgLPS stimulation. PMID:23739851

49 CFR 174.304 - Class 3 (flammable liquid) materials in tank cars.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Class 3 (flammable liquid) materials in tank cars... (flammable liquid) materials in tank cars. A tank car containing a Class 3 (flammable liquid) material, other... the liquid from the tank car to permanent storage tanks of sufficient capacity to receive the entire...

49 CFR 174.304 - Class 3 (flammable liquid) materials in tank cars.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Class 3 (flammable liquid) materials in tank cars... (flammable liquid) materials in tank cars. A tank car containing a Class 3 (flammable liquid) material, other... the liquid from the tank car to permanent storage tanks of sufficient capacity to receive the entire...

49 CFR 174.304 - Class 3 (flammable liquid) materials in tank cars.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Class 3 (flammable liquid) materials in tank cars... (flammable liquid) materials in tank cars. A tank car containing a Class 3 (flammable liquid) material, other... the liquid from the tank car to permanent storage tanks of sufficient capacity to receive the entire...

49 CFR 174.304 - Class 3 (flammable liquid) materials in tank cars.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Class 3 (flammable liquid) materials in tank cars... (flammable liquid) materials in tank cars. A tank car containing a Class 3 (flammable liquid) material, other... the liquid from the tank car to permanent storage tanks of sufficient capacity to receive the entire...

Manipulation and control of the interfacial polarization in organic light-emitting diodes by dipolar doping

NASA Astrophysics Data System (ADS)

Jäger, Lars; Schmidt, Tobias D.; Brütting, Wolfgang

2016-09-01

Most of the commonly used electron transporting materials in organic light-emitting diodes exhibit interfacial polarization resulting from partially aligned permanent dipole moments of the molecules. This property modifies the internal electric field distribution of the device and therefore enables an earlier flat band condition for the hole transporting side, leading to improved charge carrier injection. Recently, this phenomenon was studied with regard to different materials and degradation effects, however, so far the influence of dilution has not been investigated. In this paper we focus on dipolar doping of the hole transporting material 4,4-bis[N-(1-naphthyl)-N-phenylamino]-biphenyl (NPB) with the polar electron transporting material tris-(8-hydroxyquinolate) aluminum (Alq3). Impedance spectroscopy reveals that changes of the hole injection voltage do not scale in a simple linear fashion with the effective thickness of the doped layer. In fact, the measured interfacial polarization reaches a maximum value for a 1:1 blend. Taking the permanent dipole moment of Alq3 into account, an increasing degree of dipole alignment is found for decreasing Alq3 concentration. This observation can be explained by the competition between dipole-dipole interactions leading to dimerization and the driving force for vertical orientation of Alq3 dipoles at the surface of the NPB layer.

Additive manufacturing of permanent magnets

DOE PAGES

Paranthaman, M. P.; Nlebedim, I. C.; Johnson, F.; ...

2016-10-28

Here, permanent magnets enable energy conversion. Motors and generators are used to convert both electrical to mechanical energy and mechanical to electrical energy, respectively. They are precharged (magnetized) prior to being used in an application and must remain magnetized during operation. In addition, they should generate sufficient magnetic flux for a given application. Nevertheless permanent magnets can be demagnetized (discharged of their magnetization) by other magnetic materials in their service vicinity, temperature changes (thermal demagnetization), microstructural degradations and the magnet’s internal demagnetizing field. Therefore a permanent magnet can be qualified based on the properties that measure its ability to withstandmore » demagnetization and to supply sufficient magnetic flux required for a given application. Some of those properties are further discussed below. Additive manufacturing followed by exchange spring magnets will be discussed afterwards.« less

Rotor for a line start permanent magnet machine

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

Melfi, Mike; Schiferl, Rich; Umans, Stephen

A rotor comprises laminations with a plurality of rotor bar slots with an asymmetric arrangement about the rotor. The laminations also have magnet slots equiangularly spaced about the rotor. The magnet slots extend near to the rotor outer diameter and have permanent magnets disposed in the magnet slots creating magnetic poles. The magnet slots may be formed longer than the permanent magnets disposed in the magnets slots and define one or more magnet slot apertures. The permanent magnets define a number of poles and a pole pitch. The rotor bar slots are spaced from adjacent magnet slots by a distancemore » that is at least 4% of the pole pitch. Conductive material is disposed in the rotor bar slots, and in some embodiments, may be disposed in the magnet slot apertures.« less

Properties of the "Orgamax" osteoplastic material made of a demineralized allograft bone

NASA Astrophysics Data System (ADS)

Podorognaya, V. T.; Kirilova, I. A.; Sharkeev, Yu. P.; Uvarkin, P. V.; Zhelezny, P. A.; Zheleznaya, A. P.; Akimova, S. E.; Novoselov, V. P.; Tupikova, L. N.

2016-08-01

We investigated properties of the "Orgamax" osteoplastic material, which was produced from a demineralized bone, in the treatment of extensive caries, in particular chronic pulpitis of the permanent teeth with unformed roots in children. The "Orgamax" osteoplastic material consists of demineralized bone chips, a collagen additive, and antibiotics. The surface morphology of the "Orgamax" osteoplastic material is macroporous, with the maximum pore size of 250 µm, whereas the surface morphology of the major component of "Orgamax", demineralized bone chips, is microporous, with a pore size of 10-20 µm. Material "Orgamax" is used in the treatment of complicated caries, particularly chronic pulpitis of permanent teeth with unformed roots in children. "Orgamax" filling a formed cavity exhibits antimicrobial properties, eliminates inflammation in the dental pulp, and, due to its osteoconductive and osteoinductive properties, undergoes gradual resorption, stimulates regeneration, and provides replacement of the defect with newly formed tissue. The dental pulp viability is completely restored, which ensures the complete formation of tooth roots with root apex closure in the long-term period.

Class II glass ionomer cermet tunnel, resin sandwich and amalgam restorations over 2 years.

PubMed

Wilkie, R; Lidums, A; Smales, R

1993-08-01

This study compared the clinical behavior of a glass ionomer (polyalkenoate) silver cermet, a posterior resin composite used with the "tunnel" technique, a posterior resin composite used with the "closed sandwich" technique, and a high-copper amalgam for restoring small, proximal surface carious lesions. Two dentists placed 86 restorations in the posterior permanent teeth of 26 adults treated at a dental hospital. Restorations were assessed at 6-month intervals over 2 years for gingivitis adjacent to them, the tightness of proximal contacts, occlusal wear, surface voids, roughness and cracking, surface and marginal staining, and marginal fracture. Small filling defects, surface voids and occlusal wear were obvious with the cermet material, with surface crazing and cracking present in 48% of the tunnel restorations. Two of the posterior resin composites, but none of the amalgam restorations, also failed. The cermet cannot be recommended as a long-term permanent restorative material in situations where it is likely to be subjected to heavy occlusal stresses and abrasive wear.

Evaluation of Iron Loss in Interior Permanent Magnet Synchronous Motor with Consideration of Rotational Field

NASA Astrophysics Data System (ADS)

Ma, Lei; Sanada, Masayuki; Morimoto, Shigeo; Takeda, Yoji; Kaido, Chikara; Wakisaka, Takeaki

Loss evaluation is an important issue in the design of electrical machines. Due to the complicate structure and flux distribution, it is difficult to predict the iron loss in the machines exactly. This paper studies the iron loss in interior permanent magnet synchronous motors based on the finite element method. The iron loss test data of core material are used in the fitting of the hysteresis and eddy current loss constants. For motors in practical operation, additional iron losses due to the appearance of rotation of flux density vector and harmonic flux density distribution makes the calculation data deviates from the measured ones. Revision is made to account for these excess iron losses which exist in the practical operating condition. Calculation results show good consistence with the experimental ones. The proposed method provides a possible way to predict the iron loss of the electrical machine with good precision, and may be helpful in the selection of the core material which is best suitable for a certain machine.

(The relationship between microstructure and magnetic properties in high-energy permanent magnets characterized by polytwinned structures)

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

Not Available

1992-01-01

This report summarizes the results of a study of the relationship between microstructure and magnetic properties in a unique genre of ferromagnetic material characterized by a polysynthetically twinned structure which arises during solid state transformation. These results stem from the work over a period of approximately 27 months of a nominal 3 year grant period. The report also contains a proposal to extend the research project for an additional 3 years. The polytwinned structures produce an inhomogeneous magnetic medium in which the easy axis of magnetization varies quasi-periodically giving rise to special domain configurations which are expected to markedly influencemore » the mechanism of magnetization reversal and hysteresis behavior of these materials in bulk or thin films. The extraordinary permanent magnet properties exhibited by the well-known Co-Pt alloys as well as the Fe-Pt and Fe-Pd systems near the equiatomic composition derive from the formation of a polytwinned microstructure.« less

[The relationship between microstructure and magnetic properties in high-energy permanent magnets characterized by polytwinned structures

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

Not Available

1992-07-01

This report summarizes the results of a study of the relationship between microstructure and magnetic properties in a unique genre of ferromagnetic material characterized by a polysynthetically twinned structure which arises during solid state transformation. These results stem from the work over a period of approximately 27 months of a nominal 3 year grant period. The report also contains a proposal to extend the research project for an additional 3 years. The polytwinned structures produce an inhomogeneous magnetic medium in which the easy axis of magnetization varies quasi-periodically giving rise to special domain configurations which are expected to markedly influencemore » the mechanism of magnetization reversal and hysteresis behavior of these materials in bulk or thin films. The extraordinary permanent magnet properties exhibited by the well-known Co-Pt alloys as well as the Fe-Pt and Fe-Pd systems near the equiatomic composition derive from the formation of a polytwinned microstructure.« less

The relationship between microstructure and magnetic properties in high-energy permanent magnets characterized by polytwinned structures

NASA Astrophysics Data System (ADS)

This report summarizes the results of a study of the relationship between microstructure and magnetic properties in a unique genre of ferromagnetic material characterized by a polysynthetically twinned structure which arises during solid state transformation. These results stem from the work over a period of approximately 27 months of a nominal 3 year grant period. The report also contains a proposal to extend the research project for an additional 3 years. The polytwinned structures produce an inhomogeneous magnetic medium in which the easy axis of magnetization varies quasi-periodically giving rise to special domain configurations which are expected to markedly influence the mechanism of magnetization reversal and hysteresis behavior of these materials in bulk or thin films. The extraordinary permanent magnet properties exhibited by the well-known Co-Pt alloys as well as the Fe-Pt and Fe-Pd systems near the equiatomic composition derive from the formation of a polytwinned microstructure.

Injection laryngoplasty with micronized dermis: a 10-year experience with 381 injections in 344 patients.

PubMed

Tan, Melin; Woo, Peak

2010-12-01

Micronized Dermis (MD) has been used for injection laryngoplasty for correction of glottic insufficiency since 2000. There is controversy whether the material is temporary or permanent. This is a retrospective review of 381 injections in 344 patients. From this review, we hope to better define the role of MD in injection laryngoplasty. Retrospective chart review from a single surgeon (2000-2010) The indications for MD were for both temporary and permanent correction of glottic insufficiency. The diagnoses were: vocal fold paralysis (n = 216), scar (n = 51), atrophy (n = 42), sulcus (n = 22), and others (n = 13). The material has the best effect when placed into the membranous vocal fold just lateral to the vocal ligament. The operative and postoperative complication was 1.05%. Twenty-nine percent of all injections resulted in unwanted absorption. Overinjection was needed and transcervical approach was preferred to prevent implant extrusion with overinjection. The median volume of injected material has increased from 0.8 cc to 1.0 cc over the decade. In 159 patients with long-term follow-up (>1 year), there was a 14% incidence of reinjection. Despite this, the overall need for open procedures in patients with long-term follow-up was 20%. Despite the problems of inconsistency in preparation, slow absorption and need for overinjection, micronized dermis is a safe allograft material that has long-term (>1 year) stability. The material may reduce the need for open surgery. It can be used for both temporary and permanent vocal fold augmentation.

Determine Important Nuclear Fragmentation Processes for Space Radiation Protection in Human Space Explorations

NASA Technical Reports Server (NTRS)

Lin, Zi-wei

2004-01-01

Space radiation from cosmic ray particles is one of the main challenges for long-term human space explorations such as a permanent moon base or a trip to Mars. Material shielding may provide significant radiation protection to astronauts, and models have been developed in order to evaluate the effectiveness of different shielding materials and to predict radiation environment inside the spacecraft. In this study we determine the nuclear fragmentation cross sections which will most effect the radiation risk behind typical radiation shielding materials. These cross sections thus need more theoretical studies and accurate experimental measurements in order for us to more precisely predict the radiation risk in human space explorations.

Determine Important Nuclear Fragmentation Processes for Space Radiation Protection in Human Space Explorations

NASA Technical Reports Server (NTRS)

Lin, Zi-Wei

2004-01-01

Space radiation from cosmic ray particles is one of the main challenges for long-term human space explorations such as a permanent moon base or a trip to Mars. Material shielding may provide significant radiation protection to astronauts, and models have been developed in order to evaluate the effectiveness of different shielding materials and to predict radiation environment inside the spacecraft. In this study we determine the nuclear fragmentation cross sections which will most affect the radiation risk behind typical radiation shielding materials. These cross sections thus need more theoretical studies and accurate experimental measurements in order for us to more precisely predict the radiation risk in human space exploration.

Determine Important Nuclear Fragmentation Processes for Space Radiation Protection in Human Space Explorations

NASA Technical Reports Server (NTRS)

Lin, Zi-Wei

2004-01-01

Space radiation from cosmic ray particles is one of the main challenges for long-term human space explorations such as a permanent moon base or a trip to Mars. Material shielding may provide significant radiation protection to astronauts, and models have been developed in order to evaluate the effectiveness of different shielding materials and to predict radiation environment inside the spacecraft. In this study we determine the nuclear fragmentation cross sections which will most affect the radiation risk behind typical radiation shielding materials. These cross sections thus need more theoretical studies and accurate experimental measurements in order for us to more precisely predict the radiation risk in human space explorations.

Determinants of permanent first incisor eruption in grazing Australian Angora goats.

PubMed

McGregor, B A; Butler, K L

2011-12-01

To investigate the effects of live weight, sex and other factors on deciduous (first incisor) loss and permanent first incisor development in Angora goats. Goats were part of a pen study on the effects of energy intake in Angora does during pregnancy and lactation on kid growth and development. The design was three levels of nutrition in mid-pregnancy × two levels of postnatal nutrition in 17 randomised blocks. Conception times were calculated by using artificial insemination, with ultrasound examination 43 days after insemination. Does were fed different amounts of a formulated diet in their pens. After weaning, goats were grazed in sex groups. Deciduous first incisor loss and permanent first incisor development were recorded at 11 time points from 14 to 20 months of age. For each sex, the time for visible eruption and full development of permanent first incisor declined linearly with increased live weight by 5.9 and 5.4 days/kg live weight, respectively. The time to reach similar development stages for first permanent incisors eruption was 3 months longer for the lightest animals compared with the heaviest animals. Date of birth, birth weight, doe age, growth rates, mid-pregnancy and postnatal nutrition, parity, day of weaning and weaning weight had no detectable effect. The results explain much of the substantial range in reported first permanent incisor eruption dates for small ruminants and have application in ageing of goats, marketing of kids for meat, in the selection of animals for breeding flocks and in educational material. © 2011 The Authors. Australian Veterinary Journal © 2011 Australian Veterinary Association.

Permanent magnets composed of high temperature superconductors

NASA Technical Reports Server (NTRS)

Weinstein, Roy; Chen, In-Gann; Liu, Jay; Lau, Kwong

1991-01-01

A study of persistent, trapped magnetic field has been pursued with high-temperature superconducting (HTS) materials. The main effort is to study the feasibility of utilization of HTS to fabricate magnets for various devices. The trapped field, when not in saturation, is proportional to the applied field. Thus, it should be possible to replicate complicated field configurations with melt-textured YBa2Cu3O7 (MT-Y123) material, bypassing the need for HTS wires. Presently, materials have been developed from which magnets of 1.5 T, at 77 K, can be fabricated. Much higher field is available at lower operating temperature. Stability of a few percent per year is readily attainable. Results of studies on prototype motors and minimagnets are reported.

Reply to Jaakkola (2014): "Do animals understand invisible displacement? A critical review".

PubMed

Pepperberg, Irene M

2015-05-01

Jaakkola (2014) critiques studies that investigate nonhuman capacities to track objects undergoing invisible displacements. She states that the results of most of these studies are tainted by cuing, that conceptual understanding is lacking, and that, as a consequence, great apes are the only nonhumans to have full Stage 6 object permanence. Any critique, however, must clearly take into account all published information on the techniques being used, including more recent data that counter its negative claims. Furthermore, disagreements as to the interpretation of the underlying mechanisms, although common, need not always cast doubt on the actual findings reported. Here I present material with respect to Grey parrots (Psittacus erithacus) to counter Jaakkola's critique. First, I take issue with Jaakkola's claims of cuing, based both on data from newer studies and citations from the original material. Second, I discuss her suggestions that associative learning rather than inferential mechanisms underlie demonstrated performance, pointing out some difficulties in drawing clear lines between the 2 interpretations. In sum, I argue that Grey parrots, at least, do indeed succeed on tasks involving invisible displacement, and demonstrate full object permanence. (c) 2015 APA, all rights reserved).

Mapping pocket gopher burrow systems with expanding polyurethane foam

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

Felthauser, M.; McInroy, D.

The impetus for this study arose from the need to isolate buried chemical and radioactive waste from burrowing animals. In a study of barrier materials that inhibit burrowing by pocket gophers (Thomomys spp.) into waste material, it was necessary to map tunnel systems as a function of depth and soil type. A method of mapping burrow systems was needed that would be economical, portable, useful in a variety of soil types, and give accurate, permanent records of burrow configurations. A method is described for injecting an expanding polyurethane foam to map burrow systems in situ.

Micromagnetics of rare-earth efficient permanent magnets

NASA Astrophysics Data System (ADS)

Fischbacher, Johann; Kovacs, Alexander; Gusenbauer, Markus; Oezelt, Harald; Exl, Lukas; Bance, Simon; Schrefl, Thomas

2018-05-01

The development of permanent magnets containing less or no rare-earth elements is linked to profound knowledge of the coercivity mechanism. Prerequisites for a promising permanent magnet material are a high spontaneous magnetization and a sufficiently high magnetic anisotropy. In addition to the intrinsic magnetic properties the microstructure of the magnet plays a significant role in establishing coercivity. The influence of the microstructure on coercivity, remanence, and energy density product can be understood by using micromagnetic simulations. With advances in computer hardware and numerical methods, hysteresis curves of magnets can be computed quickly so that the simulations can readily provide guidance for the development of permanent magnets. The potential of rare-earth reduced and rare-earth free permanent magnets is investigated using micromagnetic simulations. The results show excellent hard magnetic properties can be achieved in grain boundary engineered NdFeB, rare-earth magnets with a ThMn12 structure, Co-based nano-wires, and L10-FeNi provided that the magnet’s microstructure is optimized.

10 CFR 60.102 - Concepts.

Code of Federal Regulations, 2010 CFR

2010-01-01

... openings and backfill materials, but excluding shafts, boreholes, and their seals, is designated the... structure, including openings and backfill materials, but excluding, shafts, boreholes, and their seals. (2... includes sealing of shafts. Permanent closure represents the end of active human intervention with respect...

Permanent magnet design methodology

NASA Technical Reports Server (NTRS)

Leupold, Herbert A.

1991-01-01

Design techniques developed for the exploitation of high energy magnetically rigid materials such as Sm-Co and Nd-Fe-B have resulted in a revolution in kind rather than in degree in the design of a variety of electron guidance structures for ballistic and aerospace applications. Salient examples are listed. Several prototype models were developed. These structures are discussed in some detail: permanent magnet solenoids, transverse field sources, periodic structures, and very high field structures.

Plastic behavior of polycrystalline copper at optical scales of deformation

NASA Astrophysics Data System (ADS)

Domber, Jeanette Leah

Microplasticity is permanent deformation that occurs below the proportional limit of a material. For precision deployable optical spacecraft, it is unknown how microplasticity will affect the performance of the precision structure. An examination of the rolling of thin film optical reflectors indicates a strong dependence of the post-deployed shape on the strain hardening exponent of the material. However, confirmation of the valid extension of the constitutive model used to predict the deployed shape to microscopic strain regimes is necessary. The primary objective of this thesis is threefold: determine the relationship between stress and strain at nano to microstrain levels for representative materials; determine if the relationship between microscopic and macroscopic plastic behavior can be accurately characterized by the Ramberg-Osgood strain hardening constitutive model with a single set of material parameters; and determine if dislocation motion is the root cause of microplastic behavior at room temperature. The test apparatus, with a dynamic force range of 40,000 to 1, measures strains from 0.01 to 1000 parts per million (ppm) of cylindrical amorphous quartz and cold-worked and annealed tempered polycrystalline copper specimen. Elastic behavior in all three materials was consistent with typical values. However, plastic responses were larger than expected. Stresses on the order of 10 to 10,000 kPa (1.45 to 1450 psi) produced permanent strain in all three types of materials ranging from 0.01 to 1 ppm, some of which was attributable to a systematic error in the measurement. Extrapolating macroplastic behavior to lower stress and strain values underestimates the amount of microplasticity observed in the material. Therefore, material property characterization is required at all strain levels that are of concern for a particular application. The similarity in the levels of measured permanent strain for a given stress level between the as-drawn and annealed copper is consistent with the observed dislocation substructure of the two materials, which is also similar. This uniformity indicates that microplastic behavior at room temperature is driven by dislocation glide.

Periodontal ligament injection versus routine local infiltration for nonsurgical single posterior maxillary permanent tooth extraction: comparative double-blinded randomized clinical study

PubMed Central

Al-Shayyab, Mohammad H

2017-01-01

Aim The aim of this study was to evaluate the efficacy of, and patients’ subjective responses to, periodontal ligament (PDL) anesthetic injection compared to traditional local-anesthetic infiltration injection for the nonsurgical extraction of one posterior maxillary permanent tooth. Materials and methods All patients scheduled for nonsurgical symmetrical maxillary posterior permanent tooth extraction in the Department of Oral and Maxillofacial Surgery at the University of Jordan Hospital, Amman, Jordan over a 7-month period were invited to participate in this prospective randomized double-blinded split-mouth study. Every patient received the recommended volume of 2% lidocaine with 1:100,000 epinephrine for PDL injection on the experimental side and for local infiltration on the control side. A visual analog scale (VAS) and verbal rating scale (VRS) were used to describe pain felt during injection and extraction, respectively. Statistical significance was based on probability values <0.05 and measured using χ2 and Student t-tests and nonparametric Mann–Whitney and Kruskal–Wallis tests. Results Of the 73 patients eligible for this study, 55 met the inclusion criteria: 32 males and 23 females, with a mean age of 34.87±14.93 years. Differences in VAS scores and VRS data between the two techniques were statistically significant (P<0.001) and in favor of the infiltration injection. Conclusion The PDL injection may not be the alternative anesthetic technique of choice to routine local infiltration for the nonsurgical extraction of one posterior maxillary permanent tooth. PMID:29070950

Superconductor Permanent Magnets for Advanced Propulsion Applications

NASA Astrophysics Data System (ADS)

Putman, Phil; Zhou, Yuxiang; Salama, Kamel; Robertson, Tony; Bond, Deborah D.

2005-02-01

Improved trapped fields of 17 T at 29 K and 11.2 T at 47 K have been reported for the melt-textured YBCO superconductor material. Such high field strengths give the possibility for producing superconductor permanent magnets (SCPM) for plasma-related space propulsion applications, such as the anti-matter trap, magnetohydrodynamic (MHD) propulsion and electrical power generation, and others that are under development or being studied. The SCPM could be beneficial in reducing the weight-to-power ratio for the associated delivery and containment systems needed for plasma interactions that are inherently imbedded in many of these propulsion systems. In this paper, a review of the superconductor literature is presented, followed by uses of the SCPM in high-performance space propulsion applications.

A lunar space station

NASA Technical Reports Server (NTRS)

Trinh, LU; Merrow, Mark; Coons, Russ; Iezzi, Gabrielle; Palarz, Howard M.; Nguyen, Marc H.; Spitzer, Mike; Cubbage, Sam

1989-01-01

A concept for a space station to be placed in low lunar orbit in support of the eventual establishment of a permanent moon base is proposed. This space station would have several functions: (1) a complete support facility for the maintenance of the permanent moon base and its population; (2) an orbital docking area to facilitate the ferrying of materials and personnel to and from Earth; (3) a zero gravity factory using lunar raw materials to grow superior GaAs crystals for use in semiconductors and mass produce inexpensive fiber glass; and (4) a space garden for the benefit of the air food cycles. The mission scenario, design requirements, and technology needs and developments are included as part of the proposal.

Magnetocaloric effect: permanent magnet array for generation of high magnetic fields

NASA Astrophysics Data System (ADS)

Lee, Seong-Jae; Kenkel, John; Jiles, David

2002-03-01

The magnetocaloric effect (MCE), the heating or cooling of magnetic materials in a magnetic field, is unusually large in the Gd_5(Si_xGe_1-x)4 alloy system. Normally the maximum in the MCE occurs at the Curie temperature (Tc) because the spin entropy change is a maximum. By suitable selection of the composition of this alloy system the Curie temperature can be changed over the range 25 K for x = 0 to 340 K for x =1, and the composition range around x = 0.5 exhibits the largest magnetocaloric effect. In order to increase the amount of heat exchanged the change in applied magnetic field should be as large as possible, and in this research values above 1.5 Tesla are suggested. We have studied a permanent magnet array based on NdFeB, which with a remanent magnetization of only 1.2 Tesla can still generate a magnetic flux density, or magnetic induction B of 2-3 Tesla. In order to generate the high magnetic induction in the absence of a power supply, a modified hollow cylindrical permanent magnet array (HCPMA) has been designed to produce the required strength of magnetic field. Soft magnetic materials including permalloy (NiFe) were used for focusing the magnetic field in the central region. The magnitude of the magnetic flux density at the center was about 2 Tesla. The magnitude and homogeneity of the magnetic field for this design are comparable with the conventional C-shaped yoke and HCPMA. This can be easily adapted for a low power rotary system in which the magnetocaloric material can be exposed alternately to high and low magnetic fields so that it can accept and reject heat from its surroundings.

Evaluation of the effect of food and beverages on enamel and restorative materials by SEM and Fourier transform infrared spectroscopy.

PubMed

Sari, Mustafa Erhan; Erturk, Aliye Gediz; Koyuturk, Alp Erdin; Bekdemir, Yunus

2014-01-01

To examine different types of restorative materials used in children as well as primary and permanent teeth enamel when affected by erosive foods. Buttermilk, fruit yoghurt, Coca-cola, fruit juice, Filtek Z-250, Dyract Extra, Fuji II LC, and Fuji IX and tooth enamel were used. Measurements were performed on 1-day, 1-week, 1-month, 3-month, 6-month time periods by using ATR-FTIR technique and surface of the specimens were examined with SEM. Permanent tooth showed the least change among human tooth samples when compared to restorative materials. Among filler materials, the most change was observed in Fuji IX. In terms of beverages the most changes on absorption peaks obtained from spectra were seen on the samples held in Coca-Cola and orange-juice. The exposure of human enamel and restorative materials to acidic drinks may accelerate the degradation process and so reduce the life time of filler materials at equivalent integral exposure times longer than three months. Clinical Relevance Erosive foods and drinks having acidic potential destroy not only tooth enamel but also restorative materials. Copyright © 2013 Wiley Periodicals, Inc.

[Development of RF coil of permanent magnet mini-magnetic resonance imager and mouse imaging experiments].

PubMed

Hou, Shulian; Xie, Huantong; Chen, Wei; Wang, Guangxin; Zhao, Qiang; Li, Shiyu

2014-10-01

In the development of radio frequency (RF) coils for better quality of the mini-type permanent magnetic resonance imager for using in the small animal imaging, the solenoid RF coil has a special advantage for permanent magnetic system based on analyses of various types.of RF coils. However, it is not satisfied for imaging if the RF coils are directly used. By theoretical analyses of the magnetic field properties produced from the solenoid coil, the research direction was determined by careful studies to raise further the uniformity of the magnetic field coil, receiving coil sensitivity for signals and signal-to-noise ratio (SNR). The method had certain advantages and avoided some shortcomings of the other different coil types, such as, birdcage coil, saddle shaped coil and phased array coil by using the alloy materials (from our own patent). The RF coils were designed, developed and made for keeled applicable to permanent magnet-type magnetic resonance imager, multi-coil combination-type, single-channel overall RF receiving coil, and applied for a patent. Mounted on three instruments (25 mm aperture, with main magnetic field strength of 0.5 T or 1.5 T, and 50 mm aperture, with main magnetic field strength of 0.48 T), we performed experiments with mice, rats, and nude mice bearing tumors. The experimental results indicated that the RF receiving coil was fully applicable to the permanent magnet-type imaging system.

Permanent effect of a cryogenic spill on fracture properties of structural steels

NASA Astrophysics Data System (ADS)

Keseler, H.; Westermann, I.; Kandukuri, S. Y.; Nøkleby, J. O.; Holmedal, B.

2015-12-01

Fracture analysis of a standard construction steel platform deck, which had been exposed to a liquid nitrogen spill, showed that the brittle fracture started at a flaw in the weld as a consequence of low-temperature embrittlement and thermal stresses experienced by the material. In the present study, the permanent effect of a cryogenic spill on the fracture properties of carbon steels has been investigated. Charpy V-notch impact testing was carried out at 0 °C using specimens, from the platform deck material. The average impact energy appeared to be below requirements only for transverse specimens. No pre-existing damage was found when examining the fracture surfaces and cross sections in the scanning electron microscope. Specimens of the platform deck material and a DOMEX S355 MCD carbon steel were tensile tested immersed in liquid nitrogen. Both steels showed a considerable increase in yield- and fracture strength and a large increase in the Lüders strain compared to the room temperature behavior. A cryogenic spill was simulated by applying a constant tensile force to the specimens for 10 min, at -196 C. Subsequent tensile tests at room temperature showed no significant influence on the stress-strain curve of the specimens. A small amount of microcracks were found after holding a DOMEX S355 MCD specimen at a constant force below the yield point. In a platform deck material tensile tested to fracture in liquid nitrogen, cracks associated with elongated MnS inclusions were found through the whole test region. These cracks probably formed as a result of the inclusions having a higher thermal contraction rate than the steel, causing decohesion at the inclusion-matrix interface on cooling. Simultaneous deformation may have caused formation of cracks. Both the microcracks and sulphide related damage may give permanently reduced impact energy after a cryogenic exposure.

Net shape processing of alnico magnets by additive manufacturing

DOE PAGES

White, Emma Marie Hamilton; Kassen, Aaron Gregory; Simsek, Emrah; ...

2017-06-07

Alternatives to rare earth permanent magnets, such as alnico, will reduce supply instability, increase sustainability, and could decrease the cost of permanent magnets, especially for high temperature applications, such as traction drive motors. Alnico magnets with moderate coercivity, high remanence, and relatively high energy product are conventionally processed by directional solidification and (significant) final machining, contributing to increased costs and additional material waste. Additive manufacturing (AM) is developing as a cost effective method to build net-shape three-dimensional parts with minimal final machining and properties comparable to wrought parts. This work describes initial studies of net-shape fabrication of alnico magnets bymore » AM using a laser engineered net shaping (LENS) system. High pressure gas atomized (HPGA) pre-alloyed powders of two different modified alnico “8” compositions, with high purity and sphericity, were built into cylinders using the LENS process, followed by heat treatment. The magnetic properties showed improvement over their cast and sintered counterparts. The resulting alnico permanent magnets were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), and hysteresisgraph measurements. Furthermore, these results display the potential for net-shape processing of alnico permanent magnets for use in next generation traction drive motors and other applications requiring high temperatures and/or complex engineered part geometries.« less

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

White, Emma Marie Hamilton; Kassen, Aaron Gregory; Simsek, Emrah

Alternatives to rare earth permanent magnets, such as alnico, will reduce supply instability, increase sustainability, and could decrease the cost of permanent magnets, especially for high temperature applications, such as traction drive motors. Alnico magnets with moderate coercivity, high remanence, and relatively high energy product are conventionally processed by directional solidification and (significant) final machining, contributing to increased costs and additional material waste. Additive manufacturing (AM) is developing as a cost effective method to build net-shape three-dimensional parts with minimal final machining and properties comparable to wrought parts. This work describes initial studies of net-shape fabrication of alnico magnets bymore » AM using a laser engineered net shaping (LENS) system. High pressure gas atomized (HPGA) pre-alloyed powders of two different modified alnico “8” compositions, with high purity and sphericity, were built into cylinders using the LENS process, followed by heat treatment. The magnetic properties showed improvement over their cast and sintered counterparts. The resulting alnico permanent magnets were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electron backscatter diffraction (EBSD), and hysteresisgraph measurements. Furthermore, these results display the potential for net-shape processing of alnico permanent magnets for use in next generation traction drive motors and other applications requiring high temperatures and/or complex engineered part geometries.« less

Cryogenic Permanent Magnet Undulators

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

Chavanne, J.; Lebec, G.; Penel, C.

For an in-vacuum undulator operated at small gaps the permanent magnet material needs to be highly resistant to possible electron beam exposure. At room temperature, one generally uses Sm{sub 2}Co{sub 17} or high coercivity NdFeB magnets at the expense of a limited field performance. In a cryogenic permanent magnet undulator (CPMU), at a temperature of around 150 K, any NdFeB grade reveals a coercivity large enough to be radiation resistant. In particular, very high remanence NdFeB material can be used to build undulators with enhanced field and X-ray brilliance at high photon energy provided that the pre-baking of the undulatormore » above 100 deg. C can be eliminated. The ESRF has developed a full scale 2 m long CPMU with a period of 18 mm. This prototype has been in operation on the ID6 test beamline since January 2008. A significant effort was put into the characterization of NdFeB material at low temperature, the development of dedicated magnetic measurement systems and cooling methods. The measured heat budget with beam is found to be larger than expected without compromising the smooth operation of the device. Leading on from this first experience, new CPMUs are currently being considered for the upgrade of the ESRF.« less

Temporal Modulation of Stem Cell Activity Using Magnetoactive Hydrogels.

PubMed

Abdeen, Amr A; Lee, Junmin; Bharadwaj, N Ashwin; Ewoldt, Randy H; Kilian, Kristopher A

2016-10-01

Cell activity is coordinated by dynamic interactions with the extracellular matrix, often through stimuli-mediated spatiotemporal stiffening and softening. Dynamic changes in mechanics occur in vivo through enzymatic or chemical means, processes which are challenging to reconstruct in cell culture materials. Here a magnetoactive hydrogel material formed by embedding magnetic particles in a hydrogel matrix is presented whereby elasticity can be modulated reversibly by attenuation of a magnetic field. Orders of magnitude change in elasticity using low magnetic fields are shown and reversibility of stiffening with simple permanent magnets is demonstrated. The broad applicability of this technique is demonstrated with two therapeutically relevant bioactivities in mesenchymal stem cells: secretion of proangiogenic molecules, and dynamic control of osteogenesis. The ability to reversibly stiffen cell culture materials across the full spectrum of soft tissue mechanics, using simple materials and commercially available permanent magnets, makes this approach viable for a broad range of laboratory environments. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An Assessment of Direct Restorative Material Use in Posterior Teeth by American and Canadian Pediatric Dentists: II. Rubber Dam Isolation.

PubMed

Varughese, Rae E; Andrews, Paul; Sigal, Michael J; Azarpazhooh, Amir

2016-11-15

The purpose of this study was to assess usage, indications, and contraindications for rubber dam isolation (RDI) by pediatric dentists in Canada and the United States. A cross-sectional, web-based, self-administered survey was utilized to collect the opinions of all active pediatric dentist members of the Royal College of Dentists of Canada and the American Academy of Pediatric Dentistry on the use of direct restorative materials in posterior teeth (n equals 4,648; 19.3 percent response rate). The main survey also included a domain on the RDI utilization and its perceived indications and contraindications. Bivariate and multivariate analyses for RDI usage and its predictor were performed at two-tailed P<0.05. A response rate of 19.3 percent was obtained. Most participants (72.5 percent) reported using RDI "all the time." The material with the lowest usage of RDI was composite (82 percent) in the primary dentition and stainless steel crown (80.7 percent) in the permanent dentition. The three top-noted reasons for not using RDI included decreased trauma to the patient (66.2 percent), being able to prevent soft tissue from interfering without using RDI (55.9 percent), and decreased time for appointments (45.6 percent). Rubber dam isolation was valued by the majority of pediatric dentists when restoring primary and permanent dentition for all materials.

Atomic force microscopic comparison of remineralization with casein-phosphopeptide amorphous calcium phosphate paste, acidulated phosphate fluoride gel and iron supplement in primary and permanent teeth: An in-vitro study

PubMed Central

Agrawal, Nikita; Shashikiran, N. D.; Singla, Shilpy; Ravi, K. S.; Kulkarni, Vinaya Kumar

2014-01-01

Context: Demineralization of tooth by erosion is caused by frequent contact between the tooth surface and acids present in soft drinks. Aim: The present study objective was to evaluate the remineralization potential of casein-phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste, 1.23% acidulated phosphate fluoride (APF) gel and iron supplement on dental erosion by soft drinks in human primary and permanent enamel using atomic force microscopy (AFM). Materials and Methods: Specimens were made from extracted 15 primary and 15 permanent teeth which were randomly divided into three treatment groups: CPP-ACP paste, APF gel and iron supplement. AFM was used for baseline readings followed by demineralization and remineralization cycle. Results and Statistics: Almost all group of samples showed remineralization that is a reduction in surface roughness which was higher with CPP-ACP paste. Statistical analysis was performed using by one-way ANOVA and Mann-Whitney U-test with P < 0.05. Conclusions: It can be concluded that the application of CPP-ACP paste is effective on preventing dental erosion from soft drinks. PMID:24808700

Teaching Aids and Work with Models in E-Learning Environments

ERIC Educational Resources Information Center

Jancaríková, Katerina; Jancarík, Antonín

2017-01-01

PISA study has defined several key areas to be paid attention to by teachers. One of these areas is work with models. The term model can be understood very broadly, it can refer to a drawing of a chemical reaction, a plastic model, a permanent mount (taxidermy) to advanced 3D projections. Teachers are no longer confined to teaching materials and…

Atraumatic restorative treatment with resin-modified glass ionomer material: short-term results of a pilot study.

PubMed

Dülgergil, Coruh Türksel; Soyman, Mübin; Civelek, Arzu

2005-01-01

The aim of this study was to assess the feasibility of the resin-modified glass ionomer (RMGI) material in atraumatic restorative treatment (ART) approach and compare RMGI with the high-strength traditional glass ionomer cement (GIC) in permanent teeth with one or more surface-carious cavities. This study was conducted in a village school in rural southeastern Anatolia, Turkey. The RMGI and GIC restorations with the ART technique were placed randomly employing a split mouth design. In addition, the ART approach was used when necessary for both primary and/or permanent teeth with no pulpal involvement and no perceived pain before treatment. Ninety-one fillings were placed on contralateral molar pairs of 37 children. Baseline and 6-month evaluation of the fillings were made with the classic ART, modified Ryge and USPHS criteria. Based on the ART criteria, 100% of RMGI and 92.4% of GIC restorations were classified as successful after 6 months, and the difference between the 2 groups was statistically significant (p=0.009). While marginal discoloration was the commonest failure in the RMGI group according to both the modified Ryge and USPHS criteria, unsatisfactory surface texture and low anatomic form were the commonly seen failures in the ART technique. Generally, for each rating system, RMGI exhibited better clinical performance than GIC in all categories, except for marginal discoloration. Results based on the 6-month evaluation show that RMGI can be an alternative material to the GIC. Copyright (c) 2005 S. Karger AG, Basel.

Electronically commutated dc motors for electric vehicles

NASA Technical Reports Server (NTRS)

Maslowski, E. A.

1981-01-01

A motor development program to explore the feasibility of electronically commutated dc motors (also known as brushless) for electric cars is described. Two different design concepts and a number of design variations based on these concepts are discussed. One design concept is based on a permanent magnet, medium speed, machine rated at 7000 to 9000 rpm, and powered via a transistor inverter power conditioner. The other concept is based on a permanent magnet, high speed, machine rated at 22,000 to 26,000 rpm, and powered via a thyristor inverter power conditioner. Test results are presented for a medium speed motor and a high speed motor each of which have been fabricated using samarium cobalt permanent magnet material.

An evaluation of dental operative simulation materials.

PubMed

He, Li-Hong; Foster Page, Lyndie; Purton, David

2012-01-01

The study was to evaluate the performance of different materials used in dental operative simulation and compare them with those of natural teeth. Three typical phantom teeth materials were compared with extracted permanent teeth by a nanoindentation system and evaluated by students and registered dentists on the drilling sensation of the materials. Moreover, the tool life (machinability) of new cylindrical diamond burs on cutting the sample materials was tested and the burs were observed. Although student and dentist evaluations were scattered and inconclusive, it was found that elastic modulus (E) and hardness (H) were not the main factors in determining the drilling sensation of the materials. The sensation of drilling is a reflection of cutting force and power consumption.An ideal material for dental simulation should be able to generate similar drilling resistance to that of natural tooth, which is the machinability of the material.

The Weathering of Aluminum Alloy Sheet Materials Used in Aircraft

NASA Technical Reports Server (NTRS)

Mutchler, Willard

1935-01-01

This report presents the results of an investigation of the corrosion of aluminum alloy sheet materials used in aircraft. It has for its purpose to study the causes of corrosion embrittlement in duralumin-type alloys and the development of methods for its elimination. The report contains results, obtained in an extensive series of weather-exposure tests, which reveal the extent to which the resistance of the materials to corrosion was affected by variable factors in their heat treatment and by the application of various surface protective coatings. The results indicate that the sheet materials are to be regarded as thoroughly reliable, from the standpoint of their permanence in service, provided proper precautions are taken to render them corrosion-resistant.

Corneal edema and permanent blue discoloration of a silicone intraocular lens by methylene blue.

PubMed

Stevens, Scott; Werner, Liliana; Mamalis, Nick

2007-01-01

To report a silicone intraocular lens (IOL) stained blue by inadvertent intraoperative use of methylene blue instead of trypan blue and the results of experimental staining of various lens materials with different concentrations of the same dye. A "blue dye" was used to enhance visualization during capsulorhexis in a patient undergoing phacoemulsification with implantation of a three-piece silicone lens. Postoperatively, the patient presented with corneal edema and a discolored IOL. Various IOL materials were experimentally stained using methylene blue. Sixteen lenses (4 silicone, 4 hydrophobic acrylic, 4 hydrophilic acrylic, and 4 polymethylmethacrylate) were immersed in 0.5 mL of methylene blue at concentrations of 1%, 0.1%, 0.01%, and 0.001%. These lenses were grossly and microscopically evaluated for discoloration 6 and 24 hours after immersion. The corneal edema resolved within 1 month after the initial surgical procedure. After explantation, gross and microscopic analyses of the explanted silicone lens revealed that its surface and internal substance had been permanently stained blue. In the experimental study, all of the lenses except the polymethylmethacrylate lenses were permanently stained by methylene blue. The hydrophilic acrylic lenses showed the most intense blue staining in all dye concentrations. This is the first clinicopathological report of IOL discoloration due to intraocular use of methylene blue. This and other tissue dyes may be commonly found among surgical supplies in the operating room and due diligence is necessary to avoid mistaking these dyes for those commonly used during ocular surgery.

Design and damping force characterization of a new magnetorheological damper activated by permanent magnet flux dispersion

NASA Astrophysics Data System (ADS)

Lee, Tae-Hoon; Han, Chulhee; Choi, Seung-Bok

2018-01-01

This work proposes a novel type of tunable magnetorheological (MR) damper operated based solely on the location of a permanent magnet incorporated into the piston. To create a larger damping force variation in comparison with the previous model, a different design configuration of the permanent-magnet-based MR (PMMR) damper is introduced to provide magnetic flux dispersion in two magnetic circuits by utilizing two materials with different magnetic reluctance. After discussing the design configuration and some advantages of the newly designed mechanism, the magnetic dispersion principle is analyzed through both the formulated analytical model of the magnetic circuit and the computer simulation based on the magnetic finite element method. Sequentially, the principal design parameters of the damper are determined and fabricated. Then, experiments are conducted to evaluate the variation in damping force depending on the location of the magnet. It is demonstrated that the new design and magnetic dispersion concept are valid showing higher damping force than the previous model. In addition, a curved structure of the two materials is further fabricated and tested to realize the linearity of the damping force variation.

Design and analysis of a 3D-flux flux-switching permanent magnet machine with SMC cores and ferrite magnets

NASA Astrophysics Data System (ADS)

Liu, Chengcheng; Wang, Youhua; Lei, Gang; Guo, Youguang; Zhu, Jianguo

2017-05-01

Since permanent magnets (PM) are stacked between the adjacent stator teeth and there are no windings or PMs on the rotor, flux-switching permanent magnet machine (FSPMM) owns the merits of good flux concentrating and robust rotor structure. Compared with the traditional PM machines, FSPMM can provide higher torque density and better thermal dissipation ability. Combined with the soft magnetic composite (SMC) material and ferrite magnets, this paper proposes a new 3D-flux FSPMM (3DFFSPMM). The topology and operation principle are introduced. It can be found that the designed new 3DFFSPMM has many merits over than the traditional FSPMM for it can utilize the advantages of SMC material. Moreover, the PM flux of this new motor can be regulated by using the mechanical method. 3D finite element method (FEM) is used to calculate the magnetic field and parameters of the motor, such as flux density, inductance, PM flux linkage and efficiency map. The demagnetization analysis of the ferrite magnet is also addressed to ensure the safety operation of the proposed motor.

Analysis of Crystal Structure of Fe3O4 Thin Films Based on Iron Sand Growth by Spin Coating Method

NASA Astrophysics Data System (ADS)

Rianto, D.; Yulfriska, N.; Murti, F.; Hidayati, H.; Ramli, R.

2018-04-01

Recently, iron sand used as one of base materials in the steel industry. However, the content of iron sand can be used as starting materials in sensor technology in the form of thin films. In this paper, we report the analysis of crystal structure of magnetite thin film based on iron sand from Tiram’s Beach. The magnetic content of sand separated by a permanent magnet, then it was milled at 30 hours milling time. In order to increase the purity of magnetite, it washed after milling using aquades under magnetic separation by a magnet permanent. The thin film has been prepared using iron (III) nitrate by sol–gel technique. The precursor is resulted by dissolving magnetite in oxalic acid and nitric acid. Then, solution of iron (III) nitrate dissolved in ethylene glycol was applied on glass substrates by spin coating. The X-Ray Diffraction is operated thin film characterization. The structure of magnetite has been studied based on X-Ray Peaks that correspond to magnetite content of thin films.

First report on soapnut extract-mediated synthesis of sulphur-substituted nanoscale NdFeB permanent magnets and their characterization

NASA Astrophysics Data System (ADS)

Jayapala Rao, G. V. S.; Prasad, T. N. V. K. V.; Shameer, Syed; Arun, T.; Purnachandra Rao, M.

2017-10-01

Biosynthesis of nanoscale materials has its own advantages over other physical and chemical methods. Using soapnut extract as reducing and stabilizing agent for the synthesis of inorganic nanoscale materials is novel and has not been exploited to its potential so far. Herein, we report for the first time on the effects of sulphur substitution on soapnut extract-mediated synthesis of nanoscale NdFeB (S-NdFeB) permanent magnetic powders (Nd 15%, Fe 77.5%, B 7.5% and S with molar ratios: 0.1, 0.2, 0.3, 0.4, and 0.5). To synthesize, a 10 ml of 10% soapnut extract was added to 90 ml of respective chemical composition and heated to 60 °C for 30 min and aged for 24 h. The dried powder was sintered at 500 °C for 1 h. The characterization of the as-prepared nanoscale S-NdFeB magnetic materials was done using the techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersion spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS for size and zeta potential measurements) and vibrating sample magnetometer (VSM)-hysteresis loop studies. The results revealed that particles were highly stable (with a negative zeta potential of 25.7 mV) with irregular and spherical shape (with measured hydrodynamic diameter 6.7 and 63.5 nm). The tetragonal structures of the formed powders were revealed by XRD micrographs. Hysteresis loop studies clearly indicate the effect of S concentration on the enhanced magnetization of the materials.

40 CFR 63.681 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... features permanently integrated into the design of the unit. Emission point means an individual tank... system is not a drain and collection system that is designed and operated for the sole purpose of..., or transfer system used to manage off-site material. Off-site material service means any time when a...

40 CFR 63.681 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... features permanently integrated into the design of the unit. Emission point means an individual tank... system is not a drain and collection system that is designed and operated for the sole purpose of..., or transfer system used to manage off-site material. Off-site material service means any time when a...

Simple Experiments to Help Students Understand Magnetic Phenomena

ERIC Educational Resources Information Center

Browne, Kerry; Jackson, David P.

2007-01-01

The principles of magnetism are a common topic in most introductory physics courses, yet curricular materials exploring the behavior of permanent magnets and magnetic materials are surprisingly rare in the literature. We reviewed the literature to see how magnetism is typically covered in introductory textbooks and curricula. We found that while…

Methyl alcohol used as penetrant inspection medium for porous materials

NASA Technical Reports Server (NTRS)

Hendron, J. A.

1971-01-01

Porous material thoroughly wetted with alcohol shows persistent wet line or area at locations of cracks or porosity. Inspection is qualitative and repeatable, but is used quantitatively with select samples to grade density variations in graphite blocks. Photography is employed to achieve permanent record of results.

Materials and Techniques of Art: A Resource Kit.

ERIC Educational Resources Information Center

J.B. Speed Art Museum, Louisville, KY.

This classroom resource kit contains a presentation for 12 slides representing artworks found in the permanent collection of the J. B. Speed Art Museum (Kentucky), a teacher's manual, and an evaluation sheet. The printed document provides critical insight into the artworks and their historical era by investigating the materials and technical…

Practical Microform Materials for Libraries: Silver, Diazo, Vesicular.

ERIC Educational Resources Information Center

Veaner, Allen B.

1982-01-01

Remarks on the relative permanence and durability of three types of film in use in library microform reproduction (silver, diazo, and vesicular) and points out some technical and economic facts that govern the choice of microform materials for libraries. A 6-item reference list is included. (Author/JL)

Magnetic suspension options for spacecraft inertia-wheel applications

NASA Technical Reports Server (NTRS)

Downer, J. R.

1984-01-01

Design criteria for spacecraft inertia-wheel suspensions are listed. The advantages of magnetic suspensions over other suspension types for spacecraft inertia-wheel applications are cited along with the functions performed by magnetic suspension. The common designs for magnetic suspensions are enumerated. Materials selection of permanent magnets and core materials is considered.

Electronic Structure Calculation of Permanent Magnets using the KKR Green's Function Method

NASA Astrophysics Data System (ADS)

Doi, Shotaro; Akai, Hisazumi

2014-03-01

Electronic structure and magnetic properties of permanent magnetic materials, especially Nd2Fe14B, are investigated theoretically using the KKR Green's function method. Important physical quantities in magnetism, such as magnetic moment, Curie temperature, and anisotropy constant, which are obtained from electronics structure calculations in both cases of atomic-sphere-approximation and full-potential treatment, are compared with past band structure calculations and experiments. The site preference of heavy rare-earth impurities are also evaluated through the calculation of formation energy with the use of coherent potential approximations. Further, the development of electronic structure calculation code using the screened KKR for large super-cells, which is aimed at studying the electronic structure of realistic microstructures (e.g. grain boundary phase), is introduced with some test calculations.

Longevity of direct and indirect resin composite restorations in permanent posterior teeth: A systematic review and meta-analysis.

PubMed

da Veiga, Ana Maria Antonelli; Cunha, Amanda Carneiro; Ferreira, Daniele Masterson Tavares Pereira; da Silva Fidalgo, Tatiana Kelly; Chianca, Thomaz Kauark; Reis, Kátia Rodrigues; Maia, Lucianne Cople

2016-11-01

The aim of this systematic review and meta-analysis was to assess the differences in clinical performance in direct and indirect resin composite restorations in permanent posterior teeth. PubMed, the Cochrane Library, Web of Science, Scopus, LILACS, BBO, ClinicalTrials.gov and SiGLE were searched without restrictions. We included randomized clinical trials (RCTs) that compared the clinical performance of direct and indirect resin composite restorations in Class I and Class II cavities in permanent teeth, with at least two years of follow-up. The risk of bias tool suggested by Cochrane Collaboration was used for quality assessment. After duplicate removal, 912 studies were identified. Twenty fulfilled the inclusion criteria after the abstract screening. Two articles were added after a hand search of the reference list of included studies. After examination, nine RCTs were included in the qualitative analysis and five were considered to have a 'low' risk of bias. The overall risk difference in longevity between direct and indirect resin composite restorations in permanent posterior teeth (p>0.05) at five-year follow-up was 1.494 [0.893-2.500], and regardless of the type of tooth restored, that of molar and premolars was 0.716 [0.177-2.888] at three-year follow-up. Based on the findings, there was no difference in longevity of direct and indirect resin composite restorations regardless of the type of material and the restored tooth. Contemporary dentistry is based on minimally invasive restorations. Any indication of a less conservative technique must have unquestionable advantages. In vitro and in vivo studies reveal contradictory evidence of the clinical performance of direct and indirect resin composite restorations in posterior teeth. Thus this study clarified this doubt. Copyright © 2016 Elsevier Ltd. All rights reserved.

Toroidal-Core Microinductors Biased by Permanent Magnets

NASA Technical Reports Server (NTRS)

Lieneweg, Udo; Blaes, Brent

2003-01-01

The designs of microscopic toroidal-core inductors in integrated circuits of DC-to-DC voltage converters would be modified, according to a proposal, by filling the gaps in the cores with permanent magnets that would apply bias fluxes (see figure). The magnitudes and polarities of the bias fluxes would be tailored to counteract the DC fluxes generated by the DC components of the currents in the inductor windings, such that it would be possible to either reduce the sizes of the cores or increase the AC components of the currents in the cores without incurring adverse effects. Reducing the sizes of the cores could save significant amounts of space on integrated circuits because relative to other integrated-circuit components, microinductors occupy large areas - of the order of a square millimeter each. An important consideration in the design of such an inductor is preventing magnetic saturation of the core at current levels up to the maximum anticipated operating current. The requirement to prevent saturation, as well as other requirements and constraints upon the design of the core are expressed by several equations based on the traditional magnetic-circuit approximation. The equations involve the core and gap dimensions and the magnetic-property parameters of the core and magnet materials. The equations show that, other things remaining equal, as the maximum current is increased, one must increase the size of the core to prevent the flux density from rising to the saturation level. By using a permanent bias flux to oppose the flux generated by the DC component of the current, one would reduce the net DC component of flux in the core, making it possible to reduce the core size needed to prevent the total flux density (sum of DC and AC components) from rising to the saturation level. Alternatively, one could take advantage of the reduction of the net DC component of flux by increasing the allowable AC component of flux and the corresponding AC component of current. In either case, permanent-magnet material and the slant (if any) and thickness of the gap must be chosen according to the equations to obtain the required bias flux. In modifying the design of the inductor, one must ensure that the inductance is not altered. The simplest way to preserve the original value of inductance would be to leave the gap dimensions unchanged and fill the gap with a permanent- magnet material that, fortuitously, would produce just the required bias flux. A more generally applicable alternative would be to partly fill either the original gap or a slightly enlarged gap with a suitable permanent-magnet material (thereby leaving a small residual gap) so that the reluctance of the resulting magnetic circuit would yield the desired inductance.

Dental cavity liners for Class I and Class II resin-based composite restorations.

PubMed

Schenkel, Andrew B; Peltz, Ivy; Veitz-Keenan, Analia

2016-10-25

Resin-based composite (RBC) is currently accepted as a viable material for the restoration of caries for posterior permanent teeth requiring surgical treatment. Despite the fact that the thermal conductivity of the RBC restorative material closely approximates that of natural tooth structure, postoperative hypersensitivity is sometimes still an issue. Dental cavity liners have historically been used to protect the pulp from the toxic effects of some dental restorative materials and to prevent the pain of thermal conductivity by placing an insulating layer between restorative material and the remaining tooth structure. The objective of this review was to assess the effects of using dental cavity liners in the placement of Class I and Class II resin-based composite posterior restorations in permanent teeth in children and adults. Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 25 May 2016), the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 4) in the Cochrane Library (searched 25 May 2016), MEDLINE Ovid (1946 to 25 May 2016), Embase Ovid (1980 to 25 May 2016) and LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; 1982 to 25 May 2016). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. We included randomized controlled trials assessing the effects of the use of liners under Class I and Class II posterior resin-based composite restorations in permanent teeth (in both adults and children). We included both parallel and split-mouth designs. We utilized standard methodological procedures prescribed by Cochrane for data collection and analysis. Two review authors screened the search results and assessed the eligibility of studies for inclusion against the review inclusion criteria. We conducted risk of bias assessments and data extraction independently and in duplicate. Where information was unclear we contacted study authors for clarification. Eight studies, recruiting over 700 participants, compared the use of dental cavity liners to no liners for Class I and Class II resin-based composite restorations.Seven studies evaluated postoperative hypersensitivity measured by various methods. All studies were at unclear or high risk of bias. There was inconsistent evidence regarding postoperative hypersensitivity (either measured using cold response or patient-reported), with a benefit shown at some, but not all, time points (low-quality evidence).Four trials measured restoration longevity. Two of the studies were judged to be at high risk and two at unclear risk of bias. No difference in restoration failure rates were shown at one year follow-up, with no failures reported in either group for three of the four studies; the fourth study had a risk ratio (RR) 1.00 (95% confidence interval (CI) 0.07 to 15.00) (low-quality evidence). Three studies evaluated restoration longevity at two years follow-up and, again, no failures were shown in either group.No adverse events were reported in any of the included studies. There is inconsistent, low-quality evidence regarding the difference in postoperative hypersensitivity subsequent to placing a dental cavity liner under Class I and Class II posterior resin-based composite restorations in permanent posterior teeth in adults or children 15 years or older. Furthermore, no evidence was found to demonstrate a difference in the longevity of restorations placed with or without dental cavity liners.

Enduring Attraction: America’s Dependence On and Need to Secure Its Supply of Permanent Magnets

DTIC Science & Technology

2011-02-16

124,000 tons. For the time being, the delta is bridged using materials stock-piled at various commercial mines around the world . This will not suffice...AIR WAR COLLEGE AIR UNIVERSITY ENDURING ATTRACTION: AMERICA’S DEPENDENCE ON AND NEED TO SECURE ITS SUPPLY OF PERMANENT MAGNETS by...NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) Air University,Air War College,325 Chennault Circle

Anisotropy and Microstructure of High-Coercivity Rare Earth Iron Permanent Magnets

DTIC Science & Technology

1989-06-01

still necessary in order to achieve a high quality permanent magnet with an opera - ting temperature up to 150C. Acces1O, FO" NTIS CRA&i DTIC TAB... China , Crucible Materials and Unocal, USA) under different processing and post-sintering heat treatment conditions. Doped, "two-phase" Nd:0FebaiBe...mation for the nucleation field Ho (8,10). -15- 4.5 Al-substituted magnets These sintered magnets were produced by the Institute of Physics in Bejing

Quasi permanent superconducting magnet of very high field

NASA Technical Reports Server (NTRS)

Ren, Y.; Liu, J.; Weinstein, R.; Chen, I. G.; Parks, D.; Xu, J.; Obot, V.; Foster, C.

1993-01-01

We report on persistent field in a quasi-permanent magnet made of high temperature superconductor. The material has an average of 40 percent molar excess of Y, relative to Y1Ba2Cu3O7 and has been irradiated with high energy light ions at 200 MeV. The magnet, which traps 1.52 T at 77.3 K, traps nearly 4 T at 64.5 K. No evidence of giant flux jump or sample cracking was observed.

High damping properties of magnetic particles doped rubber composites at wide frequency

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

Tian, Ye, E-mail: schtiany@163.com; College of Material Science and Engineering, North University of China, Taiyuan 030051; Liu, Yaqing, E-mail: lyq@nuc.edu.cn

Highlights: ► A new kind of permanent magnetic rubber was prepared. ► The microstructure and magnetic properties were investigated. ► The mechanical and damping properties were discussed. ► The new material is expected to be an isolator material to a changed frequency. - Abstract: A new kind of rubber composite was prepared by doping SrFe{sub 12}O{sub 19} nanoparticles coated with silane coupling agents (Si-69) into nitrile butadiene rubber (NBR) matrix, which was characterized by the scanning electron microscopy and X-ray spectroscopy. The results showed that the SrFe{sub 12}O{sub 19} nanoparticles were well dispersed in rubber matrix. Furthermore, the mechanical andmore » magnetic properties of the rubber composites were investigated, in which the high tensile strength (15.8 MPa) and high saturation magnetization (22.9 emu/g) were observed. What is more, the high loss factor of the rubber composites was also obtained in a wide frequency range (0–100 Hz) at high loading (80 phr). The result is attributed to that the permanent magnetic field in rubber nanocomposites can absorb shock energy. These results indicate that the new kind of permanent magnetic rubber is expected to be a smart isolator material, in which the isolator will be able to adapt to a changed frequency.« less

Brachytherapy

MedlinePlus

... care for brachytherapy catheters. top of page What equipment is used? For permanent implants, radioactive material (which ... the tumor. top of page Who operates the equipment? The equipment is operated by a medical physicist, ...

The electrical properties and glass transition of some dental materials after temperature exposure.

PubMed

Marcinkowska, Agnieszka; Gauza-Wlodarczyk, Marlena; Kubisz, Leszek; Hedzelek, Wieslaw

2017-10-17

The physicochemical properties of dental materials will remain stable only when these materials in question are resistant to the changes in the oral cavity. The oral environment is subject to large temperature variations. The aim of the study was the assessment of electrical properties and glass transition of some dental materials after temperature exposure. Composite materials, compomers, materials for temporary prosthetic replacement and resin-based pit and fissure sealants were used in the study. The method used was electric conductivity of materials under changing temperature. The order of materials presenting the best characteristics for insulators was as follows: materials for temporary prosthetic replacement, resin-based pit and fissure sealants, composites, and compomers. Thanks to comparisons made between graphs during I and II heating run, the method could be used to observe changes in the heated material and determine whether the changes observed are reversible or permanent. The graphs also provided temperature values which contain information on glass transition during heating. In the oral cavity the effect of the constant temperature stimulus influences maturity of dental materials and improves their properties. But high temperatures over glass transition temperature can cause irreversible deformation and changes of the materials properties, even in a short time.

Study on the Aging Behaviors of Rubber Materials in Tension and Compression Loads

NASA Astrophysics Data System (ADS)

Jiang, Can; Wang, Hongyu; Ma, Xiaobing

Rubber materials are widely used in aviation, aerospace, shipbuilding, automobile and other military field. However, rubber materials are easy to aging, which largely restricts its using life. In working environment, due to the combined effect of heat and oxygen, vulcanized rubber will undergo degradation and crosslinking reaction which will cause elasticity decease and permanent deformation, so mostly rubber products are used under stress state. Due to the asymmetric structure and asymmetric stress distribution, mechanical stress may cause serious damage to molecular structure; therefore, this paper is aimed to analyze the aging behavior of rubber materials under tensile and compressive loadings, through analyzing experiment data, and adopting Gauss function to describe stress relaxation coefficient, to build an aging equation containing compression ratio parameter and aging time.

Wear characteristics of current aesthetic dental restorative CAD/CAM materials: two-body wear, gloss retention, roughness and Martens hardness.

PubMed

Mörmann, Werner H; Stawarczyk, Bogna; Ender, Andreas; Sener, Beatrice; Attin, Thomas; Mehl, Albert

2013-04-01

This study determined the two-body wear and toothbrushing wear parameters, including gloss and roughness measurements and additionally Martens hardness, of nine aesthetic CAD/CAM materials, one direct resin-based nanocomposite plus that of human enamel as a control group. Two-body wear was investigated in a computer-controlled chewing simulator (1.2 million loadings, 49N at 1.7Hz; 3000 thermocycles 5/50°C). Each of the 11 groups consisted of 12 specimens and 12 enamel antagonists. Quantitative analysis of wear was carried out with a 3D-surface analyser. Gloss and roughness measurements were evaluated using a glossmeter and an inductive surface profilometer before and after abrasive toothbrushing of machine-polished specimens. Additionally Martens hardness was measured. Statistically significant differences were calculated with one-way ANOVA (analysis of variance). Statistically significant differences were found for two-body wear, gloss, surface roughness and hardness. Zirconium dioxide ceramics showed no material wear and low wear of the enamel antagonist. Two-body wear of CAD/CAM-silicate and -lithium disilicate ceramics, -hybrid ceramics and -nanocomposite as well as direct nanocomposite did not differ significantly from that of human enamel. Temporary polymers showed significantly higher material wear than permanent materials. Abrasive toothbrushing significantly reduced gloss and increased roughness of all materials except zirconium dioxide ceramics. Gloss retention was highest with zirconium dioxide ceramics, silicate ceramics, hybrid ceramics and nanocomposites. Temporary polymers showed least gloss retention. Martens hardness differed significantly among ceramics, between ceramics and composites, and between resin composites and acrylic block materials as well. All permanent aesthetic CAD/CAM block materials tested behave similarly or better with respect to two-body wear and toothbrushing wear than human enamel, which is not true for temporary polymer CAD/CAM block materials. Ceramics show the best gloss retention compared to hybrid ceramics, composites and acrylic polymers. Copyright © 2013 Elsevier Ltd. All rights reserved.

System design of a near-self-supporting lunar colony.

NASA Technical Reports Server (NTRS)

Howell, J. R.; Huang, C. J.

1972-01-01

Concepts for expanding a 12-man lunar surface base to a more permanent colony of about 180 persons are studied. Guidelines for the colony design are that the colony must perform a useful function, and that design should maximize use of lunar materials and minimize requirements of resupply from the earth. The first use of lunar materials should be for oxygen production, to achieve which large electrical or thermal power inputs are necessary. Some of the efforts which should be directed toward food and plant growth are considered, and those factors from life support and waste control which bear further study are examined. Aspects of power generation, mining, and construction are discussed.

Cogging force investigation of a free piston permanent magnet linear generator

NASA Astrophysics Data System (ADS)

Abdalla, I. I.; Zainal, A. E. Z.; Ramlan, N. A.; Firmansyah; Aziz, A. R. A.; Heikal, M. R.

2017-10-01

Better performance and higher efficiency of the vehicles can be achieved by using free piston engine, in which the piston is connected directly to the linear generator and waiving of any mechanical means. The free piston engine has the ability to overcome or reduce many of the challenges, such as the carbon dioxide (CO2) emission and fossil fuel consumption. The cogging force produces undesired vibration and acoustic noise in the generator. However, the cogging force must be minimized as much as possible, in order to have a high performance. This paper studies the effects of ferromagnetic materials on the cogging force of the permanent magnet linear generator (PMLG) to be used in a free piston engine using nonlinear finite-element analysis (FEA) under ANSYS Maxwell. The comparisons have been established for the cogging force of the PMLG under various translator velocities and three different ferromagnetic materials for the stator core, namely, Silicon Steel laminations, Mild Steel and Somaloy. It has been shown that the PMLG with a stator core made of Somaloy has a lower cogging force among them. Furthermore, the induced voltage of the PMLG at different accelerations has been studied. It is found that the PMLG with Mild Steel and Somaloy, respectively give larger induced voltage. Moreover, as the translator speed increase the induced voltage increased.

Humboldt Open Ocean Disposal Site (HOODS) Survey Work 2014

EPA Pesticide Factsheets

The Humboldt Open Ocean Disposal Site (HOODS) is a dredged material disposal site located 3 nautical miles (nm) offshore of Humboldt Bay in Northern California. HOODS was permanently designated by EPA Region 9 in 1995, and has been actively used for dredged material disposal operations since then. The HOODS has received higher volumes of dredged material than predicted since its designation in 1995, mainly from USACE construction and maintenance dredging.

Whispering gallery mode resonators based on radiation-sensitive materials

NASA Technical Reports Server (NTRS)

Savchenkov, Anatoliy (Inventor); Maleki, Lutfollah (Inventor); Ilchenko, Vladimir (Inventor); Handley, Timothy A. (Inventor)

2005-01-01

Whispering gallery mode (WGM) optical resonators formed of radiation-sensitive materials to allow for permanent tuning of their resonance frequencies in a controlled manner. Two WGM resonators may be cascaded to form a composite filter to produce a second order filter function where at least one WGM resonator is formed a radiation-sensitive material to allow for proper control in the overlap of the two filter functions.

Revascularization Induced Maturogenesis of Non-Vital Immature Permanent Tooth Using Platelet-Rich-Fibrin: A Case Report.

PubMed

Nagaveni, N B; Pathak, Sidhant; Poornima, P; Joshi, Jooie S

2016-01-01

The aim of this report is to describe a novel method of revascularization therapy done in a non-vital, immature permanent tooth using Platelet-rich fibrin (PRF),in a recently developed scaffold material to overcome limitations associated with the traditional method of revascularization using natural blood clot. PRF prepared from autologous blood was placed in the root canal and patient was followed up regularly at one, three, six, nine and 12 months for detailed clinical and radiographic evaluation. At 12 months, radiographic examination revealed root elongation, root end closure, continued thickening of the root dentinal walls, obliteration of root canal space, and normal periradicular anatomy. However, more long term prospective trials and histological studies are highly needed before to testify PRF a panacea for the regenerative endodontic therapy in children.

Irrigation practices in long-term survivors of colorectal cancer with colostomies.

PubMed

Grant, Marcia; McMullen, Carmit K; Altschuler, Andrea; Hornbrook, Mark C; Herrinton, Lisa J; Wendel, Christopher S; Baldwin, Carol M; Krouse, Robert S

2012-10-01

For some patients diagnosed with rectal cancer, surgery will involve the creation of a temporary or permanent ostomy. When the colostomy is located in the sigmoid or descending colon, regulation of fecal output can occur through irrigation, a procedure that involves instilling fluid into the bowel to flush out gas and fecal material. When successfully used, irrigation can prevent fecal output between irrigations, providing some control over colostomy output. The purpose of this article is to describe participants of a large, multisite, multi-investigator study of health-related quality of life in long-term colorectal cancer survivors who answered questions about colostomy irrigation and reported the potential advantages and disadvantages of the procedure. The article also will explore healthcare professionals' role in ensuring patients and family members are educated and well informed about their options regarding temporary or permanent ostomies.

New Class of Type III Porous Liquids: A Promising Platform for Rational Adjustment of Gas Sorption Behavior

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

Shan, Weida; Fulvio, Pasquale F.; Kong, Liyun

Porous materials have already manifested their unique properties in a number of fields. Generally, all porous materials are in a solid state other than liquid, in which molecules are closely packed without porosity. “Porous” and “liquid” seem like antonyms. In this paper, we report a new class of Type 3 porous liquids based on rational coupling of microporous framework nanoparticles as porous hosts with a bulky ionic liquid as the fluid media. Positron annihilation lifetime spectroscopy (PALS) and CO 2 adsorption measurements confirm the successful engineering of permanent porosity into these liquids. Compared to common porous solid materials, as-synthesized porousmore » liquids exhibited pronounced hysteresis loops in the CO 2 sorption isotherms even at ambient conditions (298 K, 1 bar). Finally, the unique features of these novel porous liquids could bring new opportunities in many fields including gas separation and storage, air separation and regeneration, gas transport, and permanent gas storage at ambient conditions.« less

New Class of Type III Porous Liquids: A Promising Platform for Rational Adjustment of Gas Sorption Behavior

DOE PAGES

Shan, Weida; Fulvio, Pasquale F.; Kong, Liyun; ...

2017-12-26

Porous materials have already manifested their unique properties in a number of fields. Generally, all porous materials are in a solid state other than liquid, in which molecules are closely packed without porosity. “Porous” and “liquid” seem like antonyms. In this paper, we report a new class of Type 3 porous liquids based on rational coupling of microporous framework nanoparticles as porous hosts with a bulky ionic liquid as the fluid media. Positron annihilation lifetime spectroscopy (PALS) and CO 2 adsorption measurements confirm the successful engineering of permanent porosity into these liquids. Compared to common porous solid materials, as-synthesized porousmore » liquids exhibited pronounced hysteresis loops in the CO 2 sorption isotherms even at ambient conditions (298 K, 1 bar). Finally, the unique features of these novel porous liquids could bring new opportunities in many fields including gas separation and storage, air separation and regeneration, gas transport, and permanent gas storage at ambient conditions.« less

New Class of Type III Porous Liquids: A Promising Platform for Rational Adjustment of Gas Sorption Behavior.

PubMed

Shan, Weida; Fulvio, Pasquale F; Kong, Liyun; Schott, Jennifer A; Do-Thanh, Chi-Linh; Tian, Tao; Hu, Xunxiang; Mahurin, Shannon M; Xing, Huabin; Dai, Sheng

2018-01-10

Porous materials have already manifested their unique properties in a number of fields. Generally, all porous materials are in a solid state other than liquid, in which molecules are closely packed without porosity. "Porous" and "liquid" seem like antonyms. Herein, we report a new class of Type 3 porous liquids based on rational coupling of microporous framework nanoparticles as porous hosts with a bulky ionic liquid as the fluid media. Positron annihilation lifetime spectroscopy (PALS) and CO 2 adsorption measurements confirm the successful engineering of permanent porosity into these liquids. Compared to common porous solid materials, as-synthesized porous liquids exhibited pronounced hysteresis loops in the CO 2 sorption isotherms even at ambient conditions (298 K, 1 bar). The unique features of these novel porous liquids could bring new opportunities in many fields including gas separation and storage, air separation and regeneration, gas transport, and permanent gas storage at ambient conditions.

Effect of storage time on the viscoelastic properties of elastomeric impression materials.

PubMed

Papadogiannis, Dimitris; Lakes, Roderic; Palaghias, George; Papadogiannis, Yiannis

2012-01-01

The aim of this study was to evaluate creep and viscoelastic properties of dental impression materials after different storage times. Six commercially available impression materials (one polyether and five silicones) were tested after being stored for 30 min to 2 weeks under both static and dynamic testing. Shear and Young's moduli, dynamic viscosity, loss tangent and other viscoelastic parameters were calculated. Four of the materials were tested 1 h after setting under creep for three hours and recovery was recorder for 50 h. The tested materials showed differences among them, while storage time had significant influence on their properties. Young's modulus E ranged from 1.81 to 12.99 MPa with the polyether material being the stiffest. All of the materials showed linear viscoelastic behavior exhibiting permanent deformation after 50h of creep recovery. As storage time affects the materials' properties, pouring time should be limited in the first 48 h after impression. Copyright © 2011 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

A study of reusable electromechanical impedance methods for structural health monitoring of civil structures

NASA Astrophysics Data System (ADS)

Tawie, R.; Na, S.; Lee, H. K.

2013-04-01

Up to date, various studies have been conducted using electro-mechanical impedance (EMI) method on concrete, including monitoring the strength development or to find damage in the structure. Since EMI method utilizes a single piezoelectric material to be used as an actuator and a sensor simultaneously, the method has major advantages compared to other non-destructive testing methods. However the method requires a piezoelectric material to be permanently attached or embedded into a structure. Thus when monitoring multiple structures, the method may become quite expensive. In this study, two re-usable EMI methods conducted by researchers Na et al and Tawie et al are overviewed. The idea of re-usable EMI method is still relatively new, resulting in the reduction of monitoring costs since the same piezoelectric material is used as many times as possible, while ensuring better repeatability and reliability in measurements.

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2014 CFR

2014-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2010 CFR

2010-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2012 CFR

2012-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2011 CFR

2011-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 153.310 - Ventilation system type.

Code of Federal Regulations, 2013 CFR

2013-10-01

... CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS MATERIALS Design and Equipment Cargo Handling Space Ventilation § 153.310 Ventilation system type. A cargo handling space must have a permanent...

46 CFR 42.15-10 - Doors.

Code of Federal Regulations, 2010 CFR

2010-10-01

... superstructures shall be fitted with doors of steel or other equivalent material, permanently and strongly attached to the bulkhead, and framed, stiffened and fitted so that the whole structure is of equivalent...

46 CFR 42.15-10 - Doors.

Code of Federal Regulations, 2011 CFR

2011-10-01

... superstructures shall be fitted with doors of steel or other equivalent material, permanently and strongly attached to the bulkhead, and framed, stiffened and fitted so that the whole structure is of equivalent...

46 CFR 42.15-10 - Doors.

Code of Federal Regulations, 2013 CFR

2013-10-01

... superstructures shall be fitted with doors of steel or other equivalent material, permanently and strongly attached to the bulkhead, and framed, stiffened and fitted so that the whole structure is of equivalent...

46 CFR 42.15-10 - Doors.

Code of Federal Regulations, 2014 CFR

2014-10-01

... superstructures shall be fitted with doors of steel or other equivalent material, permanently and strongly attached to the bulkhead, and framed, stiffened and fitted so that the whole structure is of equivalent...

46 CFR 42.15-10 - Doors.

Code of Federal Regulations, 2012 CFR

2012-10-01

... superstructures shall be fitted with doors of steel or other equivalent material, permanently and strongly attached to the bulkhead, and framed, stiffened and fitted so that the whole structure is of equivalent...

High-Temperature Shape Memory Polymers

NASA Technical Reports Server (NTRS)

Yoonessi, Mitra; Weiss, Robert A.

2012-01-01

physical conformation changes when exposed to an external stimulus, such as a change in temperature. Such materials have a permanent shape, but can be reshaped above a critical temperature and fixed into a temporary shape when cooled under stress to below the critical temperature. When reheated above the critical temperature (Tc, also sometimes called the triggering or switching temperature), the materials revert to the permanent shape. The current innovation involves a chemically treated (sulfonated, carboxylated, phosphonated, or other polar function group), high-temperature, semicrystalline thermoplastic poly(ether ether ketone) (Tg .140 C, Tm = 340 C) mix containing organometallic complexes (Zn++, Li+, or other metal, ammonium, or phosphonium salts), or high-temperature ionic liquids (e.g. hexafluorosilicate salt with 1-propyl-3- methyl imidazolium, Tm = 210 C) to form a network where dipolar or ionic interactions between the polymer and the low-molecular-weight or inorganic compound forms a complex that provides a physical crosslink. Hereafter, these compounds will be referred to as "additives". The polymer is semicrystalline, and the high-melt-point crystals provide a temporary crosslink that acts as a permanent crosslink just so long as the melting temperature is not exceeded. In this example case, the melting point is .340 C, and the shape memory critical temperature is between 150 and 250 C. PEEK is an engineering thermoplastic with a high Young fs modulus, nominally 3.6 GPa. An important aspect of the invention is the control of the PEEK functionalization (in this example, the sulfonation degree), and the thermal properties (i.e. melting point) of the additive, which determines the switching temperature. Because the compound is thermoplastic, it can be formed into the "permanent" shape by conventional plastics processing operations. In addition, the compound may be covalently cross - linked after forming the permanent shape by S-PEEK by applying ionizing radiation ( radiation, neutrons), or by chemical crosslinking to form a covalent permanent network. With respect to other shape memory polymers, this invention is novel in that it describes the use of a thermoplastic composition that can be thermally molded or solution-cast into complex "permanent" shapes, and then reheated or redissolved and recast from solution to prepare another shape. It is also unique in that the shape memory behavior is provided by a non-polymer additive.

Determination of Frequency of the Second Mesiobuccal Canal in the Permanent Maxillary First Molar Teeth with Magnification Loupes (× 3.5)

PubMed Central

Hasan, Muhammad; Raza Khan, Farhan

2014-01-01

INTRODUCTION: The mesiobuccal root of the maxillary first molar has generated more research and clinical investigation than any root. An inability to detect and treat a second mesiobuccal (MB2) canal is a reason for endodontic failure in maxillary first molars. Modifications in the endodontic access and detection techniques, along with advancements in illumination and magnification technology, have aided in the location and treatment with the second mesiobuccal canal of maxillary first molars. OBJECTIVE: To determine the frequency of the second mesiobuccal canal in the permanent maxillary first molars with magnification loupes (× 3.5). MATERIALS AND METHODS: A total of 53 teeth were assessed using a moderate magnification for second mesiobuccal canal in mesiobuccal root of first permanent maxillary molars in vivo. Detection of this canal in maxillary first molars was done through a clinical access cavity preparation under magnification loupes (× 3.5). Data was analyzed using SPSS 15.0. Frequency distribution of variables was determined and the level of significance was kept at 0.05. RESULTS: We were able to detect second mesiobuccal canal in 27 out of 53 (50.9%) of the permanent maxillary first molars that were studied. It was found that the males tend to have a higher proportion of second mesiobuccal canals (up to 31%) as compared to the females in whom the second mesiobuccal canals could be identified only 19% of the time. Whilst, there was no association found between age, gender and chamber obliteration with the presence of second mesiobuccal canal. CONCLUSIONS: In conclusion, within its limitations, this study suggested that the use of magnification loupes enhanced both the detection (50.9%) and negotiation (86.8%) of the second mesiobuccal canals in the permanent maxillary first molars beyond what could be achieved with naked eye. PMID:25324702

New Materials Developments for Military High Power Electronics and Capacitors

DTIC Science & Technology

2009-04-27

parameters, permittivity and breakdown field strength, and can be given by equation 1. (1) Where U - energy density (J/ cm3), ε - relative material... permittivity εo - permittivity of free space (8.85418782 × 10-12 m-3 kg-1 s4 A2) Emax (V/µm) - maximum field strength before material breakdown... Permittivity can be described as the ability of the material to polar- ize in response to an electric field through separation of ions, twist- ing permanent

A Systematic Review and Meta-analysis of School Children's Caries Studies in Gulf Cooperation Council States

PubMed Central

Alayyan, Wafa; Al Halabi, Manal; Hussein, Iyad; Khamis, Amar; Kowash, Mawlood

2017-01-01

Objectives: The aim of the present study was to evaluate the prevalence and severity of dental caries school children in the Gulf Cooperation Council (GCC) area, to help the development of systematic approaches for preventive oral care programs in the GCC states and to provide sound information for oral health promotion and public health care. Materials and Methods: A comprehensive search to identify both published and unpublished articles concerning relevant studies of dental caries in children aged 6–16 years for their permanent teeth published from 1992 to 2016 with no language and time limit was performed. The search strategies employed electronic databases and incorporated both dental subject headings and free-text term. Results: The overall mean decayed, missing and filled teeth in the permanent teeth was 2.57, and the prevalence was 64.7% in the GCC area. Conclusions: Most of the studies were conducted in the Kingdom of Saudi Arabia. The results may not be a true reflection, and other countries in GCC are urged to study the prevalence and severity of caries in their children population. PMID:29026694

Constructing bald eagle nests with natural materials

Treesearch

T. G. Grubb

1995-01-01

A technique for using natural materials to build artificial nests for bald eagles (Haliaeetus leucocephalus) and other raptors is detailed. Properly constructed nests are as permanently secured to the nest tree or cliff substrate as any eagle-built nest or human-made platform. Construction normally requires about three hours and at least two people. This technique is...

Micromachined spinneret

DOEpatents

Okandan, Murat; Galambos, Paul

2007-11-06

A micromachined spinneret is disclosed which has one or more orifices through which a fiber-forming material can be extruded to form a fiber. Each orifice is surrounded by a concentric annular orifice which allows the fiber to be temporarily or permanently coated with a co-extrudable material. The micromachined spinneret can be formed by a combination of surface and bulk micromachining.

Identification and recovery of rare-earth permanent magnets from waste electrical and electronic equipment.

PubMed

Lixandru, A; Venkatesan, P; Jönsson, C; Poenaru, I; Hall, B; Yang, Y; Walton, A; Güth, K; Gauß, R; Gutfleisch, O

2017-10-01

Nd-Fe-B permanent magnets are a strategic material for a number of emerging technologies. They are a key component in the most energy efficient electric motors and generators, thus, they are vital for energy technologies, industrial applications and automation, and future forms of mobility. Rare earth elements (REEs) such as neodymium, dysprosium and praseodymium are also found in waste electrical and electronic equipment (WEEE) in volumes that grow with the technological evolution, and are marked as critical elements by the European Commission due to their high economic importance combined with significant supply risks. Recycling could be a good approach to compensate for the lack of rare earths (REs) on the market. However, less than 1% of REs are currently being recycled, mainly because of non-existing collection logistics, lack of information about the quantity of RE materials available for recycling and recycling-unfriendly product designs. To improve these lack of information, different waste streams of electrical and electronic equipment from an industrial recycling plant were analyzed in order to localize, identify and collect RE permanent magnets of the Nd-Fe-B type. This particular type of magnets were mainly found in hard disk drives (HDDs) from laptops and desktop computers, as well as in loudspeakers from compact products such as flat screen TVs, PC screens, and laptops. Since HDDs have been investigated thoroughly by many authors, this study focusses on other potential Nd-Fe-B resources in electronic waste. The study includes a systematic survey of the chemical composition of the Nd-Fe-B magnets found in the selected waste streams, which illustrates the evolution of the Nd-Fe-B alloys over the years. The study also provides an overview over the types of magnets integrated in different waste electric and electronic equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Assessment of White Spot Lesions and In-Vivo Evaluation of the Effect of CPP-ACP on White Spot Lesions in Permanent Molars of Children

PubMed Central

Munjal, Deepti; Garg, Shalini; Dhindsa, Abhishek; Sidhu, Gagandeep Kaur

2016-01-01

Introduction As hindrance of remineralisation process occurs during orthodontic therapy resulting in decalcification of enamel because number of plaque retention sites increases due to banding and bonding of appliances to teeth. Aim The present analytic study was undertaken to assess the occurrence of white spot lesions in permanent molars of children with and without orthodontic therapy and to evaluate the effect of Casein PhosphoPeptide-Amorphous Calcium Phosphate (CPP-ACP) on white spot lesions in post-orthodontic patients in a given period of time. Materials and Methods The study comprised of examination of 679 first permanent molars which were examined to assess the occurrence of smooth surface white spot lesions in children of 8 to 16 years age group. Group I comprised subjects without any orthodontic treatment and Group II comprised of subjects who had undergone orthodontic therapy. The sample size was calculated using the epi-info6 computer package. Treatment group included 20 post-orthodontic patients examined with at least one white spot lesion within the enamel who received remineralizing cream (GC Tooth Mousse, Recaldent, GC Corporation.) i.e., CPP–ACP cream two times a day for 12 consecutive weeks. Computerized image analysis method was taken to evaluate white spot lesions. These frequency and percentages were compared with chi-square test. For comparison of numeric data, paired t-test was used. Results Of the total 278 (49.6%) first permanent molars showed occurrence of smooth surface white spot lesions out of 560 in Group I and 107 (89.9%) first permanent molars showed presence of white spot lesions out of 119 debanded first permanent molars of children examined in Group II. CPP-ACP therapy group showed reduction in severity of codes which was found to be highly significant after 12 weeks and eight weeks on gingival-third, p-value (<0.001) and significant after eight weeks and four weeks on middle-third according to ICDAS II criteria and computerized image analysis. Conclusion CPP-ACP therapy minimum for 12 weeks is highly recommended as post-orthodontic treatment need in management of smooth surface white spot lesions on teeth undergoing fixed orthodontic therapy according to the present study. PMID:27437352

Superconducting Electric Machine with Permanent Magnets and Bulk HTS Elements

NASA Astrophysics Data System (ADS)

Levin, A. V.; Vasich, P. S.; Dezhin, D. S.; Kovalev, L. K.; Kovalev, K. L.; Poltavets, V. N.; Penkin, V. T.

Theoretical methods of calculating of two-dimensional magnetic fields, inductive parameters and output characteristics of the new type of high-temperature superconducting (HTS) synchronous motors with a composite rotor are presented. The composite rotor has the structure containing HTS flat elements, permanent magnets and ferromagnetic materials. The developed calculation model takes into account the concentrations and physical properties of these rotor elements. The simulation results of experimental HTS motor with a composite rotor are presented. The application of new type of HTS motor in different constructions of industrial high dynamic drivers is discussed.

Synthesis and magnetic properties of rare-earth free MnBi alloy: A high-energy hard magnetic material

NASA Astrophysics Data System (ADS)

Sharma, Sanjeev Kumar; Prakash, H. R.; Ram, S.; Pradhan, D.

2018-04-01

MnBi is a rare-earth free high-energy magnetic material useful for the permanent magnet based devices. In a simple method, a MnBi alloy was prepared by arc melting method using Mn and Bi metals in 60:40 atomic ratio. In terms of the X-ray diffraction, a crystalline MnBi phase is formed with Bi as impurity phase of the as-prepared alloy. FESEM image of chemically etched sample shows small grains throughout the alloy. SEAD pattern and lattice image were studied to understand the internal microstructure of the alloy. The thermomagnetic curves measured in ZFC-FC cycles over 5-380 K temperatures at 500 Oe field, shows the induced magnetization of 5-25 % in the sample. The coercivity values, 7.455 kOe (13.07 emu/g magnetization) at 380 K, and 5.185k Oe (14.75 emu/g magnetization) at 300 K, are observed in the M-H hysteresis loops. A decreased value 0.181kOe (18.05 emu/g magnetization) appears at 100 K due to the change in the magnetocrystalline anisotropy. The results are useful to fabricate small MnBi magnets for different permanent magnets based devices.

Comparison of the microhardness of primary and permanent teeth after immersion in two types of carbonated beverages

PubMed Central

Haghgou, Hamid R.; Haghgoo, Roza; Asdollah, Fatemah Molla

2016-01-01

Objectives: The consumption of carbonated beverages is one of the etiological factors that cause dental erosion. The purpose of this research was to compare changes in the microhardness of permanent and primary teeth after immersion in two types of carbonated beverages. Materials and Methods: This investigation was done on 30 healthy permanent molars and 30 healthy primary canines. Each group of primary and permanent teeth was subdivided into three groups of 10 teeth. The teeth was immersed in 40 ml of each of the three beverages for 5 min. One subgroup was immersed in water (as a control). The next was immersed in Lemon Delster and the last subgroup was immersed in Coca-Cola. The microhardness of enamel was measured using the Vickers method before and after immersion. Finally, the data was analyzed by paired t-test, one-way analysis of variance, and t-test. Results: Microhardness reduction in the primary teeth was significant in both the Lemon Delster and Coca-Cola groups (P < 0.05). This reduction was also statistically significant in the permanent teeth (P < 0.05). A comparison of the enamel changes in the primary teeth with permanent teeth after immersion in both beverages showed a greater microhardness reduction in the primary teeth in both the experimental groups. Conclusions: Coca-Cola and Lemon Delster caused a significant reduction of microhardness in tooth enamel. This reduction was greater in primary teeth than in permanent teeth, and was also greater after immersion in Coca-Cola than after immersion in Lemon Delster. PMID:27583223

Bonding Lexan and sapphire to form high-pressure, flame-resistant window

NASA Technical Reports Server (NTRS)

Richardson, William R.; Walker, Ernie D.

1987-01-01

Flammable materials have been studied in normal gravity and microgravity for many years. Photography plays a major role in the study of the combustion process giving a permanent visual record that can be analyzed. When these studies are extended to manned spacecraft, safety becomes a primary concern. The need for a high-pressure, flame-resistant, shatter-resistant window permitting photographic recording of combustion experiments in manned spacecraft prompted the development of a method for bonding Lexan and sapphire. Materials that resist shattering (e.g., Lexan) are not compatible with combustion experiments; the material loses strength at combustion temperatures. Sapphire is compatible with combustion temperatures in oxygen-enriched atmospheres but is subject to shattering. Combining the two materials results in a shatter-resistant, flame-resistant window. Combustion in microgravity produces a low-visibility flame; however, flame propagation and flame characteristics are readily visible as long as there is no deterioration of the image. Since an air gap between the Lexan and the sapphire would reduce transmission, a method was developed for bonding these unlike materials to minimize light loss.

Mineralogical conversion of asbestos containing materials

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

Pulsford, S.K.; Foltz, A.D.; Ek, R.B.

The principal objective of the Technical Task Plan (TTP) is to demonstrate a thermal-chemical mineralogical asbestos conversion unit at the Hanford Site, which converts non-radiological asbestos containing materials (ACMs) into an asbestos-free material. The permanent thermal-chemical mineralogical conversion of ACMs to a non-toxic, non-hazardous, potentially marketable end product should not only significantly reduce the waste stream volumes but terminate the {open_quotes}cradle to grave{close_quotes} ownership liabilities.

47 CFR 15.19 - Labelling requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... material fastened to the equipment by welding, riveting, or a permanent adhesive. The label must be... intended for use with cable service or the quality of such features are acceptable so long as such...

47 CFR 15.19 - Labelling requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... material fastened to the equipment by welding, riveting, or a permanent adhesive. The label must be... intended for use with cable service or the quality of such features are acceptable so long as such...

47 CFR 15.19 - Labelling requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... material fastened to the equipment by welding, riveting, or a permanent adhesive. The label must be... intended for use with cable service or the quality of such features are acceptable so long as such...

Waste management for different fusion reactor designs

NASA Astrophysics Data System (ADS)

Rocco, Paolo; Zucchetti, Massimo

2000-12-01

Safety and Environmental Assessment of Fusion Power (SEAFP) waste management studies performed up to 1998 concerned three power tokamak designs. In-vessel structural materials consist of V-alloys or low activation martensitic (LAM) steel; tritium-producing materials are Li 2O, Pb-17Li, Li 4SiO 4 with a Be-multiplier; coolants are helium or water. The strategy chosen reduces permanent radwaste by recycling the in-vessel materials and by clearance of the other structures. Limits of the contact dose rate and specific activity of the waste allowing such options are defined accordingly. SEAFP activities for 1999 enlarge the analysis to three additional reactors with in-vessel structures made with SiC/SiC composites. These materials cannot be recycled due to their form and, according to national regulations of E.C. countries, long-lived activation products hinder near-surface burial (NSB).

Measurements of beam current density and proton fraction of a permanent-magnet microwave ion source.

PubMed

Waldmann, Ole; Ludewigt, Bernhard

2011-11-01

A permanent-magnet microwave ion source has been built for use in a high-yield, compact neutron generator. The source has been designed to produce up to 100 mA of deuterium and tritium ions. The electron-cyclotron resonance condition is met at a microwave frequency of 2.45 GHz and a magnetic field strength of 87.5 mT. The source operates at a low hydrogen gas pressure of about 0.15 Pa. Hydrogen beams with a current density of 40 mA/cm(2) have been extracted at a microwave power of 450 W. The dependence of the extracted proton beam fraction on wall materials and operating parameters was measured and found to vary from 45% for steel to 95% for boron nitride as a wall liner material. © 2011 American Institute of Physics

Relevance of 4f-3d exchange to finite-temperature magnetism of rare-earth permanent magnets: An ab-initio-based spin model approach for NdFe{sub 12}N

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

Matsumoto, Munehisa; Akai, Hisazumi; Doi, Shotaro

2016-06-07

A classical spin model derived ab initio for rare-earth-based permanent magnet compounds is presented. Our target compound, NdFe{sub 12}N, is a material that goes beyond today's champion magnet compound Nd{sub 2}Fe{sub 14}B in its intrinsic magnetic properties with a simpler crystal structure. Calculated temperature dependence of the magnetization and the anisotropy field agrees with the latest experimental results in the leading order. Having put the realistic observables under our numerical control, we propose that engineering 5d-electron-mediated indirect exchange coupling between 4f-electrons in Nd and 3d-electrons from Fe would most critically help enhance the material's utility over the operation-temperature range.

Dark Material at the Surface of Polar Crater Deposits on Mercury

NASA Technical Reports Server (NTRS)

Neumann, Gregory A.; Cavanaugh, John F.; Sun, Xiaoli; Mazarico, Erwan; Smith, David E.; Zuber, Maria T.; Solomon, Sean C.; Paige, Daid A.

2012-01-01

Earth-based radar measurements [1-3] have yielded images of radar-bright material at the poles of Mercury postulated to be near-surface water ice residing in cold traps on the permanently shadowed floors of polar impact craters. The Mercury Laser Altimeter (MLA) on board the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft has now mapped much of the north polar region of Mercury [4] (Fig. 1). Radar-bright zones lie within polar craters or along poleward-facing scarps lying mainly in shadow. Calculations of illumination with respect to solid-body motion [5] show that at least 0.5% of the surface area north of 75deg N lies in permanent shadow, and that most such permanently shadowed regions (PSRs) coincide with radar-bright regions. MLA transmits a 1064-nm-wavelength laser pulse at 8 Hz, timing the leading and trailing edges of the return pulse. MLA can in some cases infer energy and thereby surface reflectance at the laser wavelength from the returned pulses. Surficial exposures of water ice would be optically brighter than the surroundings, but persistent surface water ice would require temperatures over all seasons to remain extremely low (<110 K). Thermal models [6,7] incorporating direct and scattered radiation, Mercury s eccentric orbit, 3:2 spin-orbit resonance, and near-zero obliquity generally do not support such conditions in all permanently shadowed craters but suggest that water ice buried near the surface (<0.5 m depth) could survive for > 1 Gy. We describe measurements of reflectivity derived from MLA pulse returns. These reflectivity data show that surface materials in the shadowed regions are darker than their surroundings, enough to strongly attenuate or extinguish laser returns. Such measurements appear to rule out widespread surface exposures of water ice. We consider explanations for the apparent low reflectivity of these regions involving other types of volatile deposit.

Cast Stone Formulation for Nuclear Waste Immobilization at Higher Sodium Concentrations

DOE PAGES

Fox, Kevin; Cozzi, Alex; Roberts, Kimberly; ...

2014-11-01

Low activity radioactive waste at U.S. Department of Energy sites can be immobilized for permanent disposal using cementitious waste forms. This study evaluated waste forms produced with simulated wastes at concentrations up to twice that of currently operating processes. The simulated materials were evaluated for their fresh properties, which determine processability, and cured properties, which determine waste form performance. The results show potential for greatly reducing the volume of material. Fresh properties were sufficient to allow for processing via current practices. Cured properties such as compressive strength meet disposal requirements. Leachability indices provide an indication of expected long-term performance.

Direct Pulp Capping with Calcium Hydroxide, Mineral Trioxide Aggregate, and Biodentine in Permanent Young Teeth with Caries: A Randomized Clinical Trial.

PubMed

Brizuela, Claudia; Ormeño, Andrea; Cabrera, Carolina; Cabezas, Roxana; Silva, Carolina Inostroza; Ramírez, Valeria; Mercade, Montse

2017-11-01

Direct pulp capping treatment is intended to preserve pulp vitality, to avoid or retard root canal treatment, and, in cases with an open apex, to allow continued root development. Historically, calcium hydroxide (CH) was the gold standard material, but nowadays calcium silicate materials (CSMs) are displacing CH because of their high bioactivity, biocompatibility, sealing ability, and mechanical properties. However, more randomized clinical trials are needed to confirm the appropriateness of CSMs as replacement materials for CH in direct pulp capping procedures. A randomized clinical trial was conducted that included 169 patients (mean age, 11.3 years) from the Maipo district (Chile). The inclusion criterion was patients with 1 carious permanent tooth with pulpal exposure, a candidate for a direct pulp capping procedure. The patients were randomly allocated to one of the experimental groups (CH, Biodentine, or mineral trioxide aggregate [MTA]). Clinical follow-up examinations were performed at 1 week, 3 months, 6 months, and 1 year. The Fisher exact test was performed. At the follow-up examination at 1 week, the patients showed 100% clinical success. At 3 months, there was 1 failure in the CH group. At 6 months, there were 4 new failures (1 in the CH group and 3 in the MTA group). At 1 year, there was another failure in the CH group. There were no statistically significant differences among the experimental groups. CSMs appear to be suitable materials to replace CH. Although no significant differences were found among the materials studied, Biodentine and MTA offered some advantages over CH. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Effect of environmental and material factors on the response of nanocomposite foam impact sensors

NASA Astrophysics Data System (ADS)

Bird, Evan; Merrell, Jake; Rosquist, Parker; Martineau, Adin; Bowden, Anton; Seeley, Matthew; Fullwood, David

2018-05-01

Nanocomposite foam (NCF) is a multifunctional material that can be used to measure impact. Interactions between the flexible polymer matrix and conductive particles dispersed throughout it produce a voltage signal under dynamic strain, which correlates to the magnitude of impact. Though promising in applications requiring both impact sensing and energy absorption, NCF’s voltage response has been observed to suffer from significant signal drift. This paper investigates several causes of variance in the response of NCF sensors to consistent impacts. These effects can be classified into three general types: recoverable transient effects (such as those relating to viscoelasticity or capacitive charging), environmental drift (due to humidity and temperature), and permanent signal decay from material degradation. The motivation for the study arises from various potential repeat-impact applications where periodic recalibration of the sensor would be difficult (such as a gait-tracking insole in use for a marathon event). A cyclic drop testing machine was used to apply consistent impacts to NCF, and drift resulting from each factor (in ranges typical of an insole environment) was experimentally isolated. Models representing each factor’s contribution to signal drift are presented. Of the factors investigated, humidity and temperature caused the most significant drift, with permanent material degradation accounting for only minor decay in voltage response. Transient effects were also observed, with a characteristic ‘warm-up’ (or ‘charging’) time required for the NCF to achieve steady-state; this phenomenon, and the related ‘recovery’ time for the material to return to its original state, were determined. The resultant data can be leveraged to implement a correction algorithm or other drift-compensating method to retain an NCF sensor’s accuracy in both long and short data collection scenarios.

Anti-graffiti nanocomposite materials for surface protection of a very porous stone

NASA Astrophysics Data System (ADS)

Licchelli, Maurizio; Malagodi, Marco; Weththimuni, Maduka; Zanchi, Chiara

2014-09-01

The preservation of stone substrates from defacement induced by graffiti represents a very challenging task, which can be faced by applying suitable protective agents on the surface. Although different anti-graffiti materials have been developed, it is often found that their effectiveness is unsatisfactory, most of all when applied on very porous stones, e.g. Lecce stone. The aim of this work was to study the anti-graffiti behaviour of new nanocomposite materials obtained by dispersing montmorillonite nanoparticles (layered aluminosilicates with a high-aspect ratio) into a fluorinated polymer matrix (a fluorinated polyurethane based on perfluoropolyether blocks). Polymeric structure was modified by inducing a cross-linking process, in order to produce a durable anti-graffiti coating with enhanced barrier properties. Several composites were prepared using a naturally occurring and an organically modified montmorillonite clay (1, 3, and 5 % w/w concentrations). Materials were applied on Lecce stone specimens, and then their treated surfaces were soiled by a black ink permanent marker or by a black acrylic spray paint. Several repeated staining/cleaning cycles were performed in order to evaluate anti-graffiti effectiveness. Colorimetric measurements were selected to assess the anti-graffiti performance. It was found that the presence of 3 % w/w organically modified montmorillonite in the polymer coating is enough to induce a durable anti-graffiti effect when the stone surface is stained by acrylic paint. Less promising results are obtained when staining by permanent marker is considered as all the investigated treatments afford a reasonable protection from ink only for the first staining/cleaning cycle.

Microstructure and Phase Analysis in Mn-Al and Zr-Co Permanent Magnets

NASA Astrophysics Data System (ADS)

Lucis, Michael J.

In America's search for energy independence, the development of rare-earth free permanent magnets is one hurdle that still stands in the way. Permanent magnet motors provide a higher efficiency than induction motors in applications such as hybrid vehicles and wind turbines. This thesis investigates the ability of two materials, Mn-Al and Zr-Co, to fill this need for a permanent magnet material whose components are readily available within the U.S. and whose supply chain is more stable than that of the rare-earth materials. This thesis focuses on the creation and optimization of these two materials to later be used as the hard phase in nanocomposites with high energy products (greater than 10 MGOe). Mn-Al is capable of forming the pure L10 structure at a composition of Mn54Al43C3. When Mn is replaced by Fe or Cu using the formula Mn48Al43C3T6 the anisotropy constant is lowered from 1.3·107 ergs/cm3 to 1.0·107 ergs/cm3 and 0.8·10 7 ergs/cm3 respectively. Previous studies have reported a loss in magnetization in Mn-Al alloys during mechanical milling. The reason for this loss in magnetization was investigated and found to be due to the formation of the equilibrium beta-Mn phase of the composition Mn3Al2 and not due to oxidation or site disorder. It was also shown that fully dense Mn-Al permanent magnets can be created at hot pressing temperatures at or above 700°C and that the epsilon-phase to tau-phase transition and consolidation can be combined into a single processing step. The addition of small amounts of Cu to the alloy, 3% atomic, can increase the compaction density allowing high densities to be achieved at lower pressing temperatures. While the structure is still under debate, alloys at the composition Zr2Co11 in the Zr-Co system have been shown to have hard magnetic properties. This thesis shows that multiple structures exist at this Zr2Co11 composition and that altering the cooling rate during solidification of the alloy affects the ratio of the phase composition and therefore affects the magnetic properties. Phase diagrams for the Zr-Co system show that the Zr2Co11 phase is stable to a temperature of 1272°C, at which point the Zr6Co23 phase is the most favorable. However, this thesis shows that the Zr6Co23 phase forms at room temperature during high energy mechanical milling and at annealing temperatures as low as 600°C. Since high energy mechanical milling was not a potential method to creating single crystalline particles, hydrogen embrittlement was investigated. Hydrochloric acid was used to induce hydrogen embrittlement in the Zr2Co11 alloy, modifying the fracture characteristics of the alloy causing it to occur primarily along grain boundaries resulting in single crystalline particles with remanent magnetization enhancement.

The Sines industrial complex monitoring programme: A preliminary report.

PubMed

Jones, M P; Catarino, F M; Sérgio, C; Bento-Pereira, F

1981-06-01

It is anticipated that the establishment of the industrial complex at Sines, Alentejo, Portugal, will have some impact on the environment. Details of the methods used in the monitoring programme are provided. Records of the epiphytic lichen vegetation in permanent quadrats have been made and changes shown in selected sites over a three year period are discussed. Material has been collected for analysis for heavy metals and the results discussed. There is considerable variation in replicates and in interspecies values. The problem of age and bio-accumulation is mentioned. Scanning electron microscopy has shown the accumulation of particulates, as yet unidentified, the quantity varying with increase in age and surface texture. A broadly based study of the local epiphytic flora is being carried out to record the present day diversity. There appears, as yet, to be no detectable influence of the industrial complex on the epiphytic flora of the permanent quadrats.

Modeling of long-term fatigue damage of soft tissue with stress softening and permanent set effects

PubMed Central

Martin, Caitlin; Sun, Wei

2012-01-01

One of the major failure modes of bioprosthetic heart valves is non-calcific structural deterioration due to fatigue of the tissue leaflets. Experimental methods to characterize tissue fatigue properties are complex and time-consuming. A constitutive fatigue model that could be calibrated by isolated material tests would be ideal for investigating the effects of more complex loading conditions. However, there is a lack of tissue fatigue damage models in the literature. To address these limitations, in this study, a phenomenological constitutive model was developed to describe the stress softening and permanent set effects of tissue subjected to long-term cyclic loading. The model was used to capture characteristic uniaxial fatigue data for glutaraldehyde-treated bovine pericardium and was then implemented into finite element software. The simulated fatigue response agreed well with the experimental data and thus demonstrates feasibility of this approach. PMID:22945802

The National Inventory of Down Woody Materials: Methods, Outputs, and Future Directions

Treesearch

Christopher W. Woodall

2003-01-01

The Forest Inventory and Analysis Program (FIA) of the USDA Forest Service conducts a national inventory of forests of the United States. A subset of FIA permanent inventory plots are sampled every year for numerous forest health indicators ranging fiom soils to understory vegetation. Down woody material (DWM) is an FIA indicator that refines estimation of forest...

Magnetic Materials

DTIC Science & Technology

1985-03-01

provides high magnetic field capabilities. The emphasis, however, has largely been on semiconaucting and superconducting materials. The lab has not...was easily magnetized and demagnetized , whereas iiardened 0reel acted as a permanent magnet , led to the terminology of hard and soBt magnetic ...similar to Alnico, have relatively low magnetization but high coercive fields. They are well suited for uses where the demagnetizing fields are high

Design of advanced beams considering elasto-plastic behaviour of material

NASA Astrophysics Data System (ADS)

Tolun, S.

1992-10-01

The paper proposes a computational procedure for precise calculation of limit and ultimate or design loads, which must be carried by an advanced aviation beam, without permanent distortion and without rupture. Among several stress-strain curve representations, one that is suitable for a particular material is chosen for applied loads, yield, and failure load calculations, and then nonlinear analysis is performed.

Fabrication and applications of electrets

NASA Technical Reports Server (NTRS)

Pillai, P. K. C.; Shriver, E. L.

1977-01-01

Permanently charged dielectrics can be made less expensively, faster, and more effectively using improved techniques and materials. Methods include charge injection, Tesla-coil charging, and molten spray. Possible uses include pollution control, low-power sensors, and illumination control.

29 CFR 1910.253 - Oxygen-fuel gas welding and cutting.

Code of Federal Regulations, 2011 CFR

2011-07-01

... threads to which permanent connections are to be made, such as to a machine. (vii) Station outlets shall... materials or processes. (6) Outside generator houses and inside generator rooms for stationary acetylene...

29 CFR 1910.253 - Oxygen-fuel gas welding and cutting.

Code of Federal Regulations, 2013 CFR

2013-07-01

... threads to which permanent connections are to be made, such as to a machine. (vii) Station outlets shall... materials or processes. (6) Outside generator houses and inside generator rooms for stationary acetylene...

29 CFR 1910.253 - Oxygen-fuel gas welding and cutting.

Code of Federal Regulations, 2012 CFR

2012-07-01

... threads to which permanent connections are to be made, such as to a machine. (vii) Station outlets shall... materials or processes. (6) Outside generator houses and inside generator rooms for stationary acetylene...

29 CFR 1910.253 - Oxygen-fuel gas welding and cutting.

Code of Federal Regulations, 2014 CFR

2014-07-01

... threads to which permanent connections are to be made, such as to a machine. (vii) Station outlets shall... materials or processes. (6) Outside generator houses and inside generator rooms for stationary acetylene...

78 FR 16472 - Deposit of Biological Materials

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-15

... and upon issuance as a patent that all restriction to public access is permanently removed. In order... by FedEx ``Domestic Overnight'' is estimated to be $75. If the shipment requires pick-up by FedEx...

Treatment decisions on Molar-Incisor Hypomineralization (MIH) by Norwegian dentists - a questionnaire study.

PubMed

Kopperud, Simen E; Pedersen, Cecilie Gravdahl; Espelid, Ivar

2016-07-04

The study aimed to explore the variability between the treatment decisions dentists make for MIH-affected teeth. In 2009, a pre-coded questionnaire was sent electronically to all dentists employed by the Public Dental Service (PDS) in Norway (n = 1061). The questions were related to treatment of MIH-affected teeth, including three patient cases illustrated by photographs and written case descriptions. Replies were obtained from 61.5 % of the respondents after two reminders. In the first case, showing a newly erupted first permanent molar with moderate hypomineralization and no disintegration of the surface enamel, the preferred treatment among the majority of the respondents (53.5 %) was application of fluoride varnish, while 19.6 % would seal the fissure with GIC material. In the second case, showing a severely damaged first permanent molar in a six year old child, more than half of the respondents (57.5 %) would place a conventional glass ionomer restoration and 10.5 % would use a stainless steel crown (SSC). In the third case, showing a severely damaged permanent first molar in a nine year old child, 43.8 % of the dentists would remove only the parts with soft, damaged enamel; while 35.2 % would remove more and 21.0 % would remove all affected enamel and leave the cavity margins in sound enamel. The survey shows that there is a wide disparity between clinicians' views on how MIH affected teeth should be treated. In a severely affected first permanent molar, only a minority of dentists would remove as much tooth substance as needed to get the full benefit of the acid etch pattern in sound enamel.

TMS 2014 143rd Annual Meeting & Exhibition, Annual Meeting Supplemental Proceedings (ISBN: 978-1-118-88972-5)

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

Nielsen, K; Zhukov, A; Ipatov, M

The Magnetic Materials for Energy Applications IV, held at the 2014, 143rd Annual Meeting of The Minerals, Metals, and Materials Society (TMS), brought together experts, young investigators, and students from this sub-discipline of materials science in order for them to share their latest discoveries and develop collaborations. This symposium, which is organized by The Minerals, Metals, and Materials Society, is an important event for this community of scientists. This year, over 50 high-level technical talks were planned over the course of the event. In addition, the students and young investigators in attendance ensured the maximum benefit to the next generation’smore » work force in this area of study. Meeting global energy needs in a clean, efficient, secure and sustainable manner is arguably the greatest challenge facing mankind today. Magnetic materials play a critical role in myriad devices for the collection, conversion, transmission and storage of energy. For example, high performance permanent magnets are currently in great demand for the generators in wind turbines and electric motors in hybrid vehicles. Other classes of advanced magnetic materials are essential for efficient inductors/transformers and motors. Energy efficient cooling based on the magnetocaloric effect is another exciting possibility which is rapidly becoming industrially viable. The potential energy savings related to refrigeration and air conditioning based on magnetocaloric materials are highly attractive. This symposium allowed experts in areas relating to the advanced characterization, simulation, and optimization of magnetic materials to convene and present their latest research. The types of interactions afforded by this event are beneficial to society at large primarily because they provide opportunities for the leaders within this field to learn from one another and thus improve the quality and productivity of their investigations. Additionally, the presence of young investigators and students with technical interests in this field provides promise that the United States will continue to be a leader in this area. The support provided by the Department of Energy for this event directly enhanced its impact on the field by helping a number of students, young investigators, and technical experts attend and participate in this event. This symposium brought together research experts and students in the field to present the latest developments on the science surrounding advanced characterization, simulation, and optimization of magnetic materials and their use in energy applications such as generation and magnetic cooling. A strong technical program, containing more than 50 presentations was developed and organized around the following technical sessions. A strong list of invited speakers contributed to the high quality of technical content. Rare Earth Permanent Magnets: Processing, Characterization and Modeling Rare Earth Free Permanent Magnets Fundamentals of the Magnetocaloric Effect and Current Status of Magnetic Cooling Technology Magnetocaloric Materials High Performance Soft Magnets I High Performance Soft Magnets II« less

Analysis and design of asymmetrical reluctance machine

NASA Astrophysics Data System (ADS)

Harianto, Cahya A.

Over the past few decades the induction machine has been chosen for many applications due to its structural simplicity and low manufacturing cost. However, modest torque density and control challenges have motivated researchers to find alternative machines. The permanent magnet synchronous machine has been viewed as one of the alternatives because it features higher torque density for a given loss than the induction machine. However, the assembly and permanent magnet material cost, along with safety under fault conditions, have been concerns for this class of machine. An alternative machine type, namely the asymmetrical reluctance machine, is proposed in this work. Since the proposed machine is of the reluctance machine type, it possesses desirable feature, such as near absence of rotor losses, low assembly cost, low no-load rotational losses, modest torque ripple, and rather benign fault conditions. Through theoretical analysis performed herein, it is shown that this machine has a higher torque density for a given loss than typical reluctance machines, although not as high as the permanent magnet machines. Thus, the asymmetrical reluctance machine is a viable and advantageous machine alternative where the use of permanent magnet machines are undesirable.

Reinforced Concrete Modeling

DTIC Science & Technology

1982-07-01

micro- cracks within the material . This microcracking causes permanent deformation and a loss in stiffness similar to the strain hardening seen in metals...approached. Dilatation is caused by the tendency of shear stresses to open cracks in a microcracked, brittle material . 10 1.2 I , e3 3 1.0 F i ,S22 e...situation would be for a user to compromise some accuracy based on what features of a material are of the most importance for the analysis involved

A New Look for the Shopping Mall

NASA Technical Reports Server (NTRS)

1985-01-01

STRUCTO-FAB, a product of Owens-Corning Fiberglas Corporation, is a lightweight but extremely durable tent-like material made of Fiberglas coated with Teflon. It transmits daylight with a reduced need for artificial lighting. It is an outgrowth of a material formulated by NASA in 1967 as a new space suit fabric. Owens-Corning and DuPont provided the original material, which was the basis for Structo-Fab, a permanent architectural fabric used for shopping malls, sports stadiums, etc.

Adhesive bonded structural repair. I - Materials and processes, damage assessment and repair

NASA Astrophysics Data System (ADS)

Wegman, Raymond F.; Tullos, Thomas R.

1993-08-01

A standard method for the repair of adhesive bonded and composite laminate structures is introduced. Suitable materials and equipment for making satisfactory repairs are identified. Methods by which structures may be inspected, both before and after repair, are discussed. The objective in selecting the methods and materials is to restore the structure to its original integrity, i.e., to make a permanent repair. The use of these methods is recommended to promote standardized repair procedures.

Percutaneous Retrieval of Permanent Inferior Vena Cava Filters

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

Tamrazi, Anobel, E-mail: atamraz1@jhmi.edu; Wadhwa, Vibhor, E-mail: vwadhwa1@jhmi.edu; Holly, Brian, E-mail: bholly3@jhmi.edu

PurposeTo evaluate the feasibility, risks, and techniques of percutaneous removal of permanent TrapEase and Simon Nitinol IVC filters.Materials and MethodsBetween August 2011 and August 2015, 12 patients (5 women, 7 men; age range, 26–75 years) underwent an attempt at percutaneous removal of permanent TrapEase (10) and Simon Nitinol (2) IVC filters due to a history of IVC filter complications or need for lifelong anticoagulation due to the filter. Medical records were reviewed for filter dwell time, presence of iliocaval deep venous thrombosis, procedural technique, and complications.ResultsFilter dwell times ranged from 7 days to 15 years (mean 5.1 years). Successful removal of permanent IVC filtersmore » was possible in 11 of 12 patients (91.6 %). In 1 patient, a chronically thrombosed IVC filter could not be removed despite laser sheath assistance, but was successfully recanalized with the PowerWire RF guidewire. In the failed retrieval attempt, a stent was placed through the chronically thrombosed IVC filter with restoration of in-line flow. One major complication of large venous groin hematoma was encountered.ConclusionsIn carefully selected patients, percutaneous removal of permanent IVC filters can be performed safely despite prolonged filter dwell times. Extraction of chronically embedded permanent IVC filters may be facilitated by jugular and femoral approaches, often with laser sheath assistance. Chronic filter thrombosis and caval scarring may increase the risk of retrieval failure.« less

The Question of Decalage Between Object Permanence and Person Permanence

ERIC Educational Resources Information Center

And Others; Jackson, Elaine

1978-01-01

Presents a study of decalage between object permanence and person permanence. Decalage was influenced by environmental as well as stimulus factors with infants tested between 6- and 81/4-months/of-age. (BD)

Magnetically attached sputter targets

DOEpatents

Makowiecki, D.M.; McKernan, M.A.

1994-02-15

An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.

Magnetically attached sputter targets

DOEpatents

Makowiecki, Daniel M.; McKernan, Mark A.

1994-01-01

An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly.

Prenatal and familial factors of caries in first permanent molars in schoolchildren living in urban area of Łódź, Poland.

PubMed

Borowska-Strugińska, Beata; Żądzińska, Elżbieta; Bruzda-Zwiech, Agnieszka; Filipińska, Renata; Lubowiecka-Gontarek, Beata; Szydłowska-Walendowska, Beata; Wochna-Sobańska, Magdalena

2016-06-01

The objective of the present work is to identify the set of prenatal and familial factors that contribute to dental caries of first permanent molars in preschool and young schoolchildren, which will make it possible to determine a high-risk group that should be considered for special preventive measures. This study contributes to the evidence for the multifactorial nature of dental caries. Material was collected during a 2009-2010 study conducted in randomly selected schools and kindergartens in the city of Łódź (Poland). Only children with first permanent molars present were considered for the analysis, which limited the database to 1131 children. Dental examinations were accompanied by a questionnaire completed by the parents, covering items pertaining to prenatal and familial determinants. The present study shows that there are significant differences in the prevalence of caries in first molars between children of different ages (5-13 lat) and that no such differences exist between boys and girls. The prenatal and familial factors conducive to caries include maternal education level (OR=0.55), mode of delivery (OR=0.63) and birth order (OR=0.63). Mothers' smoking habit is also associated with increased caries prevalence in children. Caries prevention should already begin during the prenatal period primarily in respect of mothers with lower educational attainment who are pregnant with a second or subsequent child. Copyright © 2015 Elsevier GmbH. All rights reserved.

Status and plans of NASA's Materials Science and Manufacturing in Space (MS/MS) program

NASA Technical Reports Server (NTRS)

Armstrong, W. O.; Bredt, J. H.

1972-01-01

A description is given of a research and development program on the space shuttle mission designed to prepare the way for possible commercial manufacturing operations on permanently orbiting space stations.

Technical data on new engineering products

NASA Astrophysics Data System (ADS)

1985-02-01

New grades of permanently magnetic materials; automatic digital radiolocator; bench winder; analog induction gauge; programmable pulse generator; portable defibrillators; pipe welders; two-component electromagnetic log; sulphur content analyzer; peristaltic pumps; function generators; welding manipulator; and tonsiometer are described.

Thermally actuated magnetization flux pump in single-grain YBCO bulk

NASA Astrophysics Data System (ADS)

Yan, Yu; Li, Quan; Coombs, T. A.

2009-10-01

Recent progress in material processing has proved that high temperature superconductors (HTS) have a great potential to trap large magnetic fields at cryogenic temperatures. For example, HTS are widely used in MRI scanners and in magnetic bearings. However, using traditional ways to magnetize, the YBCO will always need the applied field to be as high as the expected field on the superconductor or much higher than it, leading to a much higher cost than that of using permanent magnets. In this paper, we find a method of YBCO magnetization in liquid nitrogen that only requires the applied field to be at the level of a permanent magnet. Moreover, rather than applying a pulsed high current field on the YBCO, we use a thermally actuated material (gadolinium) as an intermedia and create a travelling magnetic field through it by changing the partial temperature so that the partial permeability is changed to build up the magnetization of the YBCO gradually after multiple pumps. The gadolinium bulk is located between the YBCO and the permanent magnet and is heated and cooled repeatedly from the outer surface to generate a travelling thermal wave inwards. In the subsequent experiment, an obvious accumulation of the flux density is detected on the surface of the YBCO bulk.

Investigation of a less rare-earth permanent-magnet machine with the consequent pole rotor

NASA Astrophysics Data System (ADS)

Bai, Jingang; Liu, Jiaqi; Wang, Mingqiao; Zheng, Ping; Liu, Yong; Gao, Haibo; Xiao, Lijun

2018-05-01

Due to the rising price of rare-earth materials, permanent-magnet (PM) machines in different applications have a trend of reducing the use of rare-earth materials. Since iron-core poles replace half of PM poles in the consequent pole (CP) rotor, the PM machine with CP rotor can be a promising candidate for less rare-earth PM machine. Additionally, the investigation of CP rotor in special electrical machines, like hybrid excitation permanent-magnet PM machine, bearingless motor, etc., has verified the application feasibility of CP rotor. Therefore, this paper focuses on design and performance of PM machines when traditional PM machine uses the CP rotor. In the CP rotor, all the PMs are of the same polarity and they are inserted into the rotor core. Since the fundamental PM flux density depends on the ratio of PM pole to iron-core pole, the combination rule between them is investigated by analytical and finite-element methods. On this basis, to comprehensively analyze and evaluate PM machine with CP rotor, four typical schemes, i.e., integer-slot machines with CP rotor and surface-mounted PM (SPM) rotor, fractional-slot machines with CP rotor and SPM rotor, are designed to investigate the performance of PM machine with CP rotor, including electromagnetic performance, anti-demagnetization capacity and cost.

Electromagnetic induction pump for pumping liquid metals and other conductive liquids

DOEpatents

Smither, R.K.

1993-05-11

An electromagnetic induction pump is described in which an electrically conductive liquid is made to flow by means of a force created by interaction of a permanent magnetic field and a DC current. The pump achieves high efficiency through combination of: powerful permanent magnet materials which provide a high strength field that is uniform and constant; steel tubing formed into a coil which is constructed to carry conducting liquids with minimal electrical resistance and heat; and application of a voltage to induce a DC current which continuously produces a force in the direction of the desired flow.

Electromagnetic induction pump for pumping liquid metals and other conductive liquids

DOEpatents

Smither, Robert K.

1993-01-01

An electromagnetic induction pump in which an electrically conductive liquid is made to flow by means of a force created by interaction of a permanent magnetic field and a DC current. The pump achieves high efficiency through combination of: powerful permanent magnet materials which provide a high strength field that is uniform and constant; steel tubing formed into a coil which is constructed to carry conducting liquids with minimal electrical resistance and heat; and application of a voltage to induce a DC current which continuously produces a force in the direction of the desired flow.

2016 ASE undergraduate essay competition candidate information.

PubMed

Chen, Alice

2018-04-01

The aim of this review is to discuss the role of medicaments and materials used in teeth undergoing root canal treatment and how they affect the overall prognosis of root canal treated teeth. Irrigants, medicaments and materials play a vital role in RCT. They reduce the overall microbial load within the root canal system, help reduce inter-appointment pain, and induce apexification during RCT of permanent teeth with immature apices. In addition, they also help create a hermetic coronal and periradicular seal to entomb any residual microorganisms within the canals and prevent future ingress of contaminants into the root canal system and subsequent reinfection. Whilst the role of various materials in RCT has been thoroughly investigated, the available literature and longitudinal clinical studies evaluating the affect of such materials on the prognosis of RCT is scarce, and requires further investigation. © 2017 Australian Society of Endodontology Inc.

A field test of point relascope sampling of down coarse woody material in managed stands in the Acadian Forest

Treesearch

John C. Brissette; Mark J. Ducey; Jeffrey H. Gove

2003-01-01

We field tested a new method for sampling down coarse woody material (CWM) using an angle gauge and compared it with the more traditional line intersect sampling (LIS) method. Permanent sample locations in stands managed with different silvicultural treatments within the Penobscot Experimental Forest (Maine, USA) were used as the sampling locations. Point relascope...

Sampling protocol, estimation, and analysis procedures for the down woody materials indicator of the FIA program

Treesearch

Christopher Woodall

2005-01-01

The Forest Inventory and Analysis (FIA) program of the USDA Forest Service conducts a national inventory of forests of the United States. A subset of FIA permanent inventory plots are sampled every year for numerous indicators of forest health ranging from soils to understory vegetation. Down woody material (DWM) is an FIA indicator that provides estimates of forest...

Laparoscopic Repair of Inguinal Hernia with Biomimetic Matrix

PubMed Central

2012-01-01

Background and Objectives: Materials utilized for the repair of hernias fall into 2 broad categories, synthetics and biologics. Each has its merits and drawbacks. The synthetics have a permanent, inherent strength but are associated with some incidence of chronic pain. The biologics rely on variable tissue regeneration to give strength to the repair, limiting their use to specific situations. However, thanks to their transient presence and tissue ingrowth, the biologics do not result in a significant incidence of chronic pain. We studied the use of a biomimetic (REVIVE, Biomerix Corporation, Fremont, CA) in this setting in an attempt to obviate the disadvantages of each material. Methods: Fourteen patients underwent laparoscopic repair by totally extraperitoneal and transabdominal preperitoneal techniques of 16 inguinal hernias. Follow-up was as long as 19 mo, and 8 patients were followed for > 12 mo. There were no recurrences and a 5% incidence of functionally insignificant discomfort. Results: REVIVE is shown in histology and in vivo to demonstrate regeneration and tissue ingrowth into the polycarbonate/polyuria matrix similar to that in the biologics rather than scarring or encapsulation. There were no recurrences, indicating its strength and resilience as a permanent repair similar to that in the synthetics. Conclusion: This is proof of the concept that a biomimetic may bridge the gap between the biologics and synthetics and may be able to be utilized on a regular basis with the benefits of both materials and without their drawbacks. PMID:23484565

The role of electronic mechanisms in surface erosion and glow phenomena

NASA Technical Reports Server (NTRS)

Haglund, Richard F., Jr.

1987-01-01

Experimental studies of desorption induced by electronic transitions (DIET) are described. Such studies are producing an increasingly complete picture of the dynamical pathways through which incident electronic energy is absorbed and rechanneled to produce macroscopic erosion and glow. These mechanistic studies can determine rate constants for erosion and glow processes in model materials and provide valuable guidance in materials selection and development. Extensive experiments with electron, photon, and heavy particle irradiation of alkali halides and other simple model materials have produced evidence showing that: (1) surface erosion, consisting primarily in the ejection or desorption of ground-state neutral atoms, occurs with large efficiencies for all irradiated species; (2) surface glow, resulting from the radiative decay of desorbed atoms, likewise occurs for all irradiating species; (3) the typical mechanism for ground-state neutral desorption is exciton formation, followed by relaxation to a permanent, mobile electronic defect which is the precursor to bond-breaking in the surface or near-surface bulk of the material; and (4) the mechanisms for excited atom formation may include curve crossing in atomic collisions, interactions with surface defect or impurity states, or defect diffusion.

Protein-based composites and biomaterials

USDA-ARS?s Scientific Manuscript database

World industrialization has generated substantial quantities of petroleum-based plastics over many years, which are not biodegradable or compostable, and are permanently residing on land, in landfills, or in the oceans, as environmental pollution. Recently, total or partially degradable materials ha...

Comparing Strategic Knowledge Gaps for Human Mars Settlement vs. Exploration

NASA Astrophysics Data System (ADS)

Mackenzie, B. A.

2012-06-01

We list knowledge needed to establish a permanent Mars base, compared that for round-trip human exploration missions. Topics include: site selection, reliable access to water, long term effects of contaminations, and in-situ materials production.

30 CFR 285.112 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... authorized under subpart J of this part. Archaeological resource means any material remains of human life or... observation, contextual measurement, controlled collection, analysis, interpretation, and explanation). Best...; pipelines; and permanently moored vessels. Any group of OCS installations interconnected with walkways, or...

4 CFR 83.3 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

...: (a) Individual means a citizen of the United States or an alien lawfully admitted for permanent residence; (b) Information means papers, records, photographs, magnetic storage media, micro storage media, and other documentary materials, regardless of physical form or characteristics, containing data about...

4 CFR 83.3 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

...: (a) Individual means a citizen of the United States or an alien lawfully admitted for permanent residence; (b) Information means papers, records, photographs, magnetic storage media, micro storage media, and other documentary materials, regardless of physical form or characteristics, containing data about...

4 CFR 83.3 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

...: (a) Individual means a citizen of the United States or an alien lawfully admitted for permanent residence; (b) Information means papers, records, photographs, magnetic storage media, micro storage media, and other documentary materials, regardless of physical form or characteristics, containing data about...

Effect of Popping Chocolate and Candy on Enamel Microhardness of Primary and Permanent Teeth

PubMed Central

Tabari, Mitra; Alaghemand, Homayoon; Qujeq, Durdi; Mohammadi, Elahe

2017-01-01

Aims and Objectives: Dental erosion is a common disease in children. Food diets, due to high amounts of juice, soft drinks, chewing gum, and acidic chocolate, are one of the most important risk factors in erosive processes among children. The aim of this study was to evaluate the effect of candy and chocolate on the microhardness of tooth enamel. Materials and Methods: Two types of popping candy and one type of popping chocolate were used in this study. Thirty-three healthy permanent premolar teeth and 33 primary incisor teeth (A or B) were selected. Five grams of each popping chocolate or candy was dissolved with 2 ml of artificial saliva. Subsequently, their pH and titrable acidity (TA) as well as microhardness and surface roughness of enamel were examined in the laboratory. Data were analyzed and evaluated Released 2011. IBM SPSS Statistics for Windows, Version 20.0. Armonk, NY through independent t-test, paired t-test, Tukey test, and ANOVA. Results: The results of this study showed that only the pH of the candies was below the critical pH of the enamel (5.5) and their TA was B = 0.20 and C = 0.21. The most significant effect on the enamel microhardness of the permanent and primary teeth was by the following types of candy: orange flavor (C), strawberry flavor (B), and chocolate (A), respectively. This difference was significant (P < 0.001) and the surface roughness increased after exposure. Conclusions: This study showed that popping chocolate and candy reduces microhardness of enamel. PMID:29387623

Long-Term Clinical Response to Treatment and Maintenance of Localized Aggressive Periodontitis: A Cohort Study

PubMed Central

Miller, Karina A. F. S.; Branco-de-Almeida, Luciana S.; Wolf, Sandra; Hovencamp, Nicole; Treloar, Tina; Harrison, Peter; Aukhil, Ikramuddin; Gong, Yan; Shaddox, Luciana M.

2016-01-01

Aim To evaluate long-term clinical response to periodontal therapy and maintenance in localized aggressive periodontitis (LAP). Materials and Methods One hundred forty-one African-Americans diagnosed with LAP, aged 5–25 years, were enrolled. Patients underwent periodontal mechanical debridement plus one week of amoxicillin/metronidazole. Mechanical therapy was repeated as needed and clinical parameters were recorded at baseline, 3, 6, 12, 18, and 24 months, and 2 additional annual follow-up visits after treatment. Radiographs from primary dentition of patients with LAP in permanent dentition, and additional healthy siblings (HS) were analyzed retrospectively. Results Periodontal therapy significantly improved probing depth and clinical attachment level up to 4 years (mean reductions: 2.18 ± 1.03 and 2.80 ± 1.43 mm, respectively). Percentage of affected sites was reduced at all timepoints and maintained up to 4 years. Noncompliance with antibiotics/appointments negatively affected the treatment response. Ninety percent of LAP patients in permanent dentition and 32% of HS presented radiographic bone loss in primary dentition. Conclusions Mechanical debridement with one-week of systemic antibiotics along with proper periodontal maintenance was effective in the treatment and successful maintenance of LAP for up to 4 years. LAP in permanent dentition may be preceded in the primary dentition. Clinicaltrials.gov #NCT01330719. PMID:27767222

Donating blood for research: a potential method for enhancing customer satisfaction of permanently deferred blood donors

PubMed Central

Waller, Daniel; Thijsen, Amanda; Garradd, Allira; Hayman, Jane; Smith, Geoff

2017-01-01

Background Each year, a large number of individuals in Australia are deferred from donating blood. A deferral may have a negative impact on donor satisfaction and subsequent word-of-mouth communication. The Australian Red Cross Blood Service (the Blood Service) is, therefore, investigating options for managing service interactions with deferred donors to maintain positive relationships. While public research institutes in Australia have established independent research donor registries, other countries provide programmes allowing deferred donors to donate blood for research via blood collection agencies. This study examined attitudes towards donating blood for research use in a sample of permanently deferred Australian donors. Materials and methods Donors permanently deferred because of a risk of variant Creutzfeldt-Jakob disease (n=449) completed a postal survey that examined attitudes towards research donation. Results The majority of participants were interested in donating blood for research (96%), and joining a registry of research donors (93%). Participants preferred to donate for transfusion or clinical research, and were willing to travel large distances. Results indicated that positive attitudes towards the Blood Service would be extended if the opportunity to donate blood was provided. These findings indicate a desire for continued engagement with the Blood Service despite deferral. Discussion Donating blood for research is a potential way of maintaining positive relationships with permanently deferred donors which also benefits the health research community. Through maintaining positive relationships with deferred donors, positive word-of-mouth activity can be stimulated. Further work is needed to determine the feasibility of implementing research donation through the Blood Service in Australia. PMID:26674813

Condyle-fossa modifications and muscle interactions during herbst treatment, part 1. New technological methods.

PubMed

Voudouris, John C; Woodside, Donald G; Altuna, Gurkan; Kuftinec, Mladen M; Angelopoulos, Gerassimos; Bourque, Paul J

2003-06-01

Changes in the condyle, the glenoid fossa, and the muscles of mastication were investigated in subjects undergoing continuous orthopedic advancement of the mandible with a Herbst-block appliance. The total sample consisted of 56 subjects and included 15 nonhuman primates (in the middle mixed, early permanent, and permanent dentitions), 17 human Herbst patients in the early permanent dentition, and 24 human controls from the Burlington Growth Center. The 8 nonhuman primates in the middle mixed dentition were the focus of this study. Mandibular advancement was obtained progressively in 5 animals by adding stops to the telescopic arms of fixed functional Herbst appliances with occlusal coverage; activations of 5.0 mm, 7.0 mm, and 8.0 mm were achieved. Two primates served as controls, and the third was a sham control. Two experimental animals and the 2 controls also wore surgically implanted electromyographic electrodes in the superior and inferior heads of the lateral pterygoid muscles and in the superficial masseter and anterior digastric muscles. Changes in condylar growth direction and amount were assessed with the Björk method from measurements made on serial cephalometric tracings superimposed on metallic implants. Undecalcified sections, treated with intravenous tetracycline vital staining, were viewed with fluorescence microscopy to examine histologic changes in the condyle and the glenoid fossa. New bone formation in the fossa associated with continuous mandibular protrusion was quantified by using computerized histomorphometric analysis of decalcified histological sections and polarized light. The unique combination of permanently implanted electromyographic electrodes, tetracycline vital staining, and histomorphometry represents a significant technological advancement in methods and materials. Together, they demonstrated different muscle-bone interaction results for functional appliances than those reported in previous studies. In Part 1 of this study, we describe and discuss the techniques used in this research and give a brief overview of the findings; in Part 2 (to be published next month), we offer a more in-depth discussion of the results and the implications of our findings.

Dentinogenic Specificity in the Preclinical Evaluation of Vital Pulp Treatment Strategies: A Critical Review.

PubMed

Tziafas, Dimitrios; Kodonas, Konstantinos

2015-11-27

Reviews on the clinical performance of vital pulp treatment strategies and capping materials repeatedly showed an insufficient grade of evidence concerning their therapeutic validity. The biological mechanisms underlying the regenerative potential of pulp-dentin complex have attracted much attention during the last two decades, since new pulp treatment modalities have been designed and tested at the preclinical level. It has been recognized that evaluation should be based on the specific ability of therapeutic interventions to signal recruitment and differentiation of odontoblast-like cells forming a matrix in a predentin-like pattern, rather than uncontrolled hard tissue deposition in a scar-like form. The aim of the present article was to critically review data from histological experimental studies on pulp capping, published during the last 7 decades. A comprehensive literature search covering the period from 1949 to 2015 was done using the Medline/Pubmed database. Inclusion of a study was dependent on having sufficient data regarding the type of capping material used and the unit of observation (human permanent tooth in vivo or animal permanent dentition; primary teeth were excluded). The post-operatively deposited matrix was categorized into three types: unspecified, osteotypic, or dentin-like matrix. One hundred fifty-two studies were included in the final evaluation. Data from the present systematic review have shown that only 30.2% of the 152 experimental histological pulp capping studies described the heterogenic nature of the hard tissue bridge formation, including osteotypic and tubular mineralized tissue. Structural characteristics of the new matrix and the associated formative cells were not provided by the remaining 106 studies. Analysis showed that more careful preclinical evaluation with emphasis on the evidence regarding the dentinogenic specificity of pulp therapies is required. It seems that selection of appropriate vital pulp treatment strategies and pulp capping materials would be further facilitated in terms of their therapeutic validity if international consensus could be reached on a select number of mandatory criteria for tissue-specific dentinogenic events.

Dentinogenic Specificity in the Preclinical Evaluation of Vital Pulp Treatment Strategies: A Critical Review

PubMed Central

Tziafas, Dimitrios; Kodonas, Konstantinos

2015-01-01

Reviews on the clinical performance of vital pulp treatment strategies and capping materials repeatedly showed an insufficient grade of evidence concerning their therapeutic validity. The biological mechanisms underlying the regenerative potential of pulp-dentin complex have attracted much attention during the last two decades, since new pulp treatment modalities have been designed and tested at the preclinical level. It has been recognized that evaluation should be based on the specific ability of therapeutic interventions to signal recruitment and differentiation of odontoblast-like cells forming a matrix in a predentin-like pattern, rather than uncontrolled hard tissue deposition in a scar-like form. The aim of the present article was to critically review data from histological experimental studies on pulp capping, published during the last 7 decades. A comprehensive literature search covering the period from 1949 to 2015 was done using the Medline/Pubmed database. Inclusion of a study was dependent on having sufficient data regarding the type of capping material used and the unit of observation (human permanent tooth in vivo or animal permanent dentition; primary teeth were excluded). The post-operatively deposited matrix was categorized into three types: unspecified, osteotypic, or dentin-like matrix. One hundred fifty-two studies were included in the final evaluation. Data from the present systematic review have shown that only 30.2% of the 152 experimental histological pulp capping studies described the heterogenic nature of the hard tissue bridge formation, including osteotypic and tubular mineralized tissue. Structural characteristics of the new matrix and the associated formative cells were not provided by the remaining 106 studies. Analysis showed that more careful preclinical evaluation with emphasis on the evidence regarding the dentinogenic specificity of pulp therapies is required. It seems that selection of appropriate vital pulp treatment strategies and pulp capping materials would be further facilitated in terms of their therapeutic validity if international consensus could be reached on a select number of mandatory criteria for tissue-specific dentinogenic events. PMID:29567934

Applicability of the Moyers' Probability Tables in Adolescents with Different Facial Biotypes

PubMed Central

Carrillo, Jorge J. Pavani; Rubial, Maria C.; Albornoz, Cristina; Villalba, Silvina; Damiani, Patricia; de Cravero, Marta Rugani

2017-01-01

Introduction: The Moyers’ probability tables are used in mixed dentition analysis to estimate the extent of space required for the alignment of canines and premolars, by correlating the mesiodistal size of lower incisors with the size of permanent canines and premolars. Objective: This study intended to evaluate the applicability of the Moyer's probability tables for predicting the mesiodistal space needed for the correct location of premolars and permanent canines non-erupted, in adolescents of the city of Cordoba, Argentina, who show different facial biotypes. Materials and Methods: Models and tele-radiographies of 478 adolescents of both genders from 10 to 15 years of age were analyzed. The tele-radiographies were measured manually in order to determine the facial biotype. The models were scanned with a gauged scanner (HP 3670) and measured by using Image Pro Plus 4.5 software. Results: According to this study, the comparison between the Moyer´s probability table, and the table created at the National University of Córdoba (UNC) (at 95%, 75%, and 50%) shows that, in both tables, a higher value of mesiodistal width of lower incisors corresponds to a bigger difference in the space needed for permanent canines and premolars; being the need for space for permanents canines and premolars bigger in the UNC´s table. On the other hand, when contrasting the values of mesiodistal space for permanent canines and premolars associated with each facial biotype, the discrepancies between groups were not statistically significant (P >0.05). However, we found differences in the size of the space required according to the mesiodistal width range of the lower incisors for each biotype: a) The comparison of lower-range values, with a mesialdistal width of lower incisors less than 22 mm, the space required for permanent canines and premolars resulted smaller in patients with dolichofacial biotype than in patients with mesofacial and braquifacial biotypes. The latter biotypes have meager differences between them. b) The comparison of mid-range values, with a mesialdistal width of lower incisors from 22 to 25 millimeters, shows that the values of required alignment space are similar in the three facial biotypes. c) Finally, the comparison of upper range values, with a mesialdistal width of lower incisors greater than 25 millimeters, indicates that the space required for dolichofacial biotypes tends to be higher than in mesofacial and brachyfacial biotypes. Conclusion: The Moyer´s probability tables should be created to meet the needs of the population under study, with no consideration of patients’ facial biotypes. PMID:28567145

Combinatorial search of rare-earth free permanent magnets

NASA Astrophysics Data System (ADS)

Gao, Tieren; Takeuchi, Ichiro; Fackler, Sean; Fang, Lei; Zhang, Ying; Krammer, Matthew; Anderson, Iver; McCallum, Bill; University of Maryland Collaboration; Ames Laboratory Collaboration

2013-03-01

Permanent magnets play important roles in modern technologies such as in generators, motors, speakers, and relays. Today's high performance permanent magnets contain at least one rare earth element such as Nd, Sm, Pr and Dy. However, rare earth elements are increasingly rare and expensive, and alternative permanent magnet materials which do not contain them are needed by the industry. We are using the thin film composition spread technique to explore novel compositions of permanent magnets without rare-earth. Ternary co-sputtering is used to generate composition spreads. We have thus far looked at Mo doped Fe-Co as one of the initial systems to search for possible compounds with enhanced coercive fields. The films were deposited on Si (100) substrates and annealed at different temperatures. The structural properties of films are mapped by synchrotron diffraction. We find that there is a structural transition from a crystalline to an amorphous state at about 20% atomic Mo. With increasing annealing temperature, the Mo onset concentration of the structural transition increases from 25% for 600°C to 35% for 700°C. We find that some of compounds display enhanced coercive field. With increasing Mo concentration, the magnetization of Fe-Co-Mo begins to switch from in-plane to out-of-plane direction. This work is funded by the BREM (Beyond Rare-earth Magnet) project (DOE EERE).

Metal-organic frameworks as functional, porous materials

NASA Astrophysics Data System (ADS)

Rood, Jeffrey A.

The research presented in this thesis investigates the use of metal carboxylates as permanently porous materials called metal-organic frameworks (MOFs). The project has focused on three broad areas of study, each which strives to develop a further understanding of this class of materials. The first topic is concerned with the synthesis and structural characterization of MOFs. Our group and others have found that the reaction of metal salts with carboxylic acids in polar solvents at elevated temperatures often leads the formation of crystalline MOF materials that can be examined by single crystal X-ray diffraction. Specifically, Chapter 2 reports on some of the first examples of magnesium MOFs, constructed from formate or aryldicarboxylate ligands. The magnesium formate MOF, [Mg3(O2CH) 6] was found to be a permanently porous 3-D material capable of selective uptake and exchange of small molecules. Once the synthesis and structures of some of these materials was known, their physical properties were studied. The magnesium formate MOF, [Mg 3(O2CH)6], was found to be permanently porous and able to reversibly adsorb both N2 and H2 gas. Furthermore, the material was also capable of taking up a variety of organic molecules to form new inclusion compounds that were characterized by XRD studies. Size exclusion was shown for cyclohexane and larger molecules. Chapters 3, 5, and 6 attempt to build off of the synthetic findings reported in Chapter 2. Specifically, the ability of these materials to take up guest molecules is expanded by the attempted synthesis of porous, homochiral MOFs using enantiopure carboxylic acids in the synthesis. It was found that under the appropriate synthetic conditions, both L-tartaric acid and (+)-camphoric acid were robust linkers for the formation of homochiral MOFs. Of the compounds synthesized, the most interesting were the set of compounds, [Zn2(Cam) 2(bipy)⊃3DMF] and [Zn2(Cam)2(apyr)⊃2DMF]. These compounds formed isoreticular cubic networks in which the pore size was dependent on the size of the linker molecule (bipy or apyr). Additonally, the compounds [Zn2(Cam)2(bipy)⊃3DMF] and [Zn2(Cam)2(apyr)⊃2DMF] were found to be capable of guest exchange. Due to their chiral nature, these materials were screened for the enanatioselective separation of racemic alcohols. No selectivity was seen with either MOF, likely owing to factors such as large pore size and disorder in the chiral camphorate ligand. [Zn2(Cam)2(bipy)⊃3DMF] contained large voids and preliminary studies showed that free-radical polymerization of methylmethacrylate could take place within the channels of the material. The amino group of the apyr ligand in [Zn2(Cam)2(apyr)⊃2DMF] was able to be functionaled with acetaldehyde by treatment of the porous MOF with the bulk organic reagent. A further area of study detailed in this work deals with a central question in MOF chemistry, concerning the assembly process of these extended materials from solution. Chapter 3 reveals that the trimeric species Mg2(HCam) 3+, the SBU for the formation of the MOF [Mg2(Hcam) 3˙3H2O]˙NO3˙MeCN, can be identified using ESI-MS on the the reaction solution prior to crystallization. Further studies showed that the addition of chelating additives led to new solid-state structures and new ions in the mass spectrum, indicating that the Mg 2(HCam)3+ ion is likely present in solution prior to MOF formation. Chapter 4 discusses extension of these ESI-MS studies on various other MOF and organometallic systems. Finally, Chapter 7 discusses the synthesis and structures of magnesium imides. These compounds were originally investigated for use as SBUs in network synthesis. This strategy proved to be unsuccessful, as the compounds form molecular clusters in the solid state. The coordination chemistry and computational studies regarding the adopted aggregation state is detailed.

A review on biodegradable materials for cardiovascular stent application

NASA Astrophysics Data System (ADS)

Hou, Li-Da; Li, Zhen; Pan, Yu; Sabir, MuhammadIqbal; Zheng, Yu-Feng; Li, Li

2016-09-01

A stent is a medical device designed to serve as a temporary or permanent internal scaffold to maintain or increase the lumen of a body conduit. The researchers and engineers diverted to investigate biodegradable materials due to the limitation of metallic materials in stent application such as stent restenosis which requires prolonged anti platelet therapy, often result in smaller lumen after implantation and obstruct re-stenting treatments. Biomedical implants with temporary function for the vascular intervention are extensively studied in recent years. The rationale for biodegradable stent is to provide the support for the vessel in predicted period of time and then degrading into biocompatible constituent. The degradation of stent makes the re-stenting possible after several months and also ameliorates the vessel wall quality. The present article focuses on the biodegradable materials for the cardiovascular stent. The objective of this review is to describe the possible biodegradable materials for stent and their properties such as design criteria, degradation behavior, drawbacks and advantages with their recent clinical and preclinical trials.

Active capping technology: a new environmental remediation of contaminated sediment.

PubMed

Zhang, Chang; Zhu, Meng-Ying; Zeng, Guang-Ming; Yu, Zhi-Gang; Cui, Fang; Yang, Zhong-Zhu; Shen, Liu-Qing

2016-03-01

The management and treatment of contaminated sediment is a worldwide problem and poses major technical and economic challenges. Nowadays, various attempts have been committed to investigating a cost-effective way in contaminated sediment restoration. Among the remediation options, in situ capping turns out to be a less expensive, less disruptive, and more durable approach. However, by using the low adsorption capacity materials, traditional caps do not always fulfill the reduction of risks that can be destructive for human health, ecosystem, and even natural resources. Active caps, therefore, are designed to employ active materials (activated carbon, apatite, zeolite, organoclay, etc.) to strengthen their adsorption and degradation capacity. The active capping technology promises to be a permanent and cost-efficient solution to contaminated sediments. This paper provides a review on the types of active materials and the ways of these active materials employed in recent active capping studies. Cap design considerations including site-specific conditions, diffusion/advection, erosive forces, and active material selection that should be noticed in an eligible remediation project are also presented.

16 CFR 1305.5 - Findings.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT REGULATIONS BAN OF ARTIFICIAL... not permanently bound into artificial fireplace logs would be in respirable form, the risk associated...) Products subject to the ban. Artificial emberizing materials are decorative simulated ashes or embers, used...

A comparison of the erosive potential of different beverages in primary and permanent teeth using an in vitro model.

PubMed

Lussi, A; Kohler, N; Zero, D; Schaffner, M; Megert, B

2000-04-01

The aim of this study was to compare the erosive potential of different beverages and foodstuffs in primary and permanent teeth. Sixty primary and 60 permanent human teeth were immersed for 3 min in the solution under study (5 teeth per treatment group). Surface microhardness was measured before and after exposure. Initial (baseline) surface microhardness was lower for primary teeth than for permanent teeth. In both primary and permanent teeth, Sprite showed the highest decrease in surface microhardness, whereas yogurt showed an increase in surface microhardness in the primary teeth. Overall decrease was 27.2 +/- 17.5 KHN (mean +/- SD) for primary and 25.9 +/- 15.6 KHN for permanent teeth. The comparison of the erosive susceptibility in this in vitro model showed that primary teeth were not more susceptible to erosion compared to permanent teeth.

Method for charging a hydrogen getter

DOEpatents

Tracy, C. Edwin; Keyser, Matthew A.; Benson, David K.

1998-01-01

A method for charging a sample of either a permanent or reversible getter material with a high concentration of hydrogen while maintaining a base pressure below 10.sup.-4 torr at room temperature involves placing the sample of hydrogen getter material in a chamber, activating the sample of hydrogen getter material, overcharging the sample of getter material through conventional charging techniques to a high concentration of hydrogen, and then subjecting the sample of getter material to a low temperature vacuum bake-out process. Application of the method results in a reversible hydrogen getter which is highly charged to maximum capacities of hydrogen and which concurrently exhibits minimum hydrogen vapor pressures at room temperatures.

A Way to Select Electrical Sheets of the Segment Stator Core Motors.

NASA Astrophysics Data System (ADS)

Enomoto, Yuji; Kitamura, Masashi; Sakai, Toshihiko; Ohara, Kouichiro

The segment stator core, high density winding coil, high-energy-product permanent magnet are indispensable technologies in the development of a compact and also high efficient motors. The conventional design method for the segment stator core mostly depended on experienced knowledge of selecting a suitable electromagnetic material, far from optimized design. Therefore, we have developed a novel design method in the selection of a suitable electromagnetic material based on the correlation evaluation between the material characteristics and motor performance. It enables the selection of suitable electromagnetic material that will meet the motor specification.

Laser Surface Treatment of Sintered Alumina

NASA Astrophysics Data System (ADS)

Hagemann, R.; Noelke, C.; Kaierle, S.; Wesling, V.

Sintered alumina ceramics are used as refractory materials for industrial aluminum furnaces. In this environment the ceramic surface is in permanent contact with molten aluminum resulting in deposition of oxidic material on its surface. Consequently, a lower volume capacity as well as thermal efficiency of the furnaces follows. To reduce oxidic adherence of the ceramic material, two laser-based surface treatment processes were investigated: a powder- based single-step laser cladding and a laser surface remelting. Main objective is to achieve an improved surface quality of the ceramic material considering the industrial requirements as a high process speed.

Flight Data Entry, Descent, and Landing (EDL) Repository

NASA Technical Reports Server (NTRS)

Martinez, Elmain M.; Winterhalter, Daniel

2012-01-01

Dr. Daniel Winterhalter, NASA Engineering and Safety Center Chief Engineer at the Jet Propulsion Laboratory, requested the NASA Engineering and Safety Center sponsor a 3-year effort to collect entry, descent, and landing material and to establish a NASA-wide archive to serve the material. The principle focus of this task was to identify entry, descent, and landing repository material that was at risk of being permanently lost due to damage, decay, and undocumented storage. To provide NASA-wide access to this material, a web-based digital archive was created. This document contains the outcome of the effort.

Teaching Object Permanence: An Action Research Study

ERIC Educational Resources Information Center

Bruce, Susan M.; Vargas, Claudia

2013-01-01

"Object permanence," also known as "object concept" in the field of visual impairment, is one of the most important early developmental milestones. The achievement of object permanence is associated with the onset of representational thought and language. Object permanence is important to orientation, including the recognition of landmarks.…

Getting Home on Time: Predicting Timely Permanence for Young Children.

ERIC Educational Resources Information Center

Potter, Cathryn C.; Klein-Rothschild, Susan

2002-01-01

Studied the multivariate predictors of timely permanence for children served by Colorado's Expedited Permanency Planning (EPP) Project. Used qualitative interviews with child welfare and court personnel to identify critical barriers to and supports for effective permanency planning focusing on the areas of: (1) concurrent planning practice and…

A review of the regenerative endodontic treatment procedure

PubMed Central

Lee, Bin-Na; Moon, Jong-Wook; Chang, Hoon-Sang; Hwang, In-Nam; Oh, Won-Mann

2015-01-01

Traditionally, apexification has been used to treat immature permanent teeth that have lost pulp vitality. This technique promotes the formation of an apical barrier to close the open apex so that the filling materials can be confined to the root canal. Because tissue regeneration cannot be achieved with apexification, a new technique called regenerative endodontic treatment was presented recently to treat immature permanent teeth. Regenerative endodontic treatment is a treatment procedure designed to replace damaged pulp tissue with viable tissue which restores the normal function of the pulp-dentin structure. After regenerative endodontic treatment, continued root development and hard tissue deposition on the dentinal wall can occur under ideal circumstances. However, it is difficult to predict the result of regenerative endodontic treatment. Therefore, the purpose of this study was to summarize multiple factors effects on the result of regenerative endodontic treatment in order to achieve more predictable results. In this study, we investigated the features of regenerative endodontic treatment in comparison with those of other pulp treatment procedures and analyzed the factors that have an effect on regenerative endodontic treatment. PMID:26295020

Summary and recommendations. [reduced gravitational effects on materials manufactured in space

NASA Technical Reports Server (NTRS)

1975-01-01

An economic analysis using econometric and cost benefit analysis techniques was performed to determine the feasibility of space processing of certain products. The overall objectives of the analysis were (1) to determine specific products or processes uniquely connected with space manufacturing, (2) to select a specific product or process from each of the areas of semiconductors, metals, and biochemicals, and (3) to determine the overall price/cost structure of each product or process considered. The economic elements of the analysis involved a generalized decision making format for analyzing space manufacturing, a comparative cost study of the selected processes in space vs. earth manufacturing, and a supply and demand study of the economic relationships of one of the manufacturing processes. Space processing concepts were explored. The first involved the use of the shuttle as the factory with all operations performed during individual flights. The second concept involved a permanent unmanned space factory which would be launched separately. The shuttle in this case would be used only for maintenance and refurbishment. Finally, some consideration was given to a permanent manned space factory.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

NASA Astrophysics Data System (ADS)

Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO 2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis, 1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

NASA Technical Reports Server (NTRS)

Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses.

PubMed

Peterson, B V; Hummerick, M; Roberts, M S; Krumins, V; Kish, A L; Garland, J L; Maxwell, S; Mills, A

2004-01-01

Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste subsystem analysis and atmospheric management within the ALS Project. Published by Elsevier Ltd on behalf of COSPAR.

Prevalence of enamel defects in primary and permanent teeth in a group of schoolchildren from Granada (Spain).

PubMed

Robles, Maria-Jesús; Ruiz, Matilde; Bravo-Perez, Manuel; González, Encarnación; Peñalver, Maria-Angustias

2013-03-01

The purpose of this study was to determine and compare the prevalence and presentations of developmental defects of the enamel (DDE) in the primary and permanent dentitions of a group of healthy schoolchildren residing in Granada (Spain). A total of 1,414 healthy schoolchildren were examined using modified DDE criteria for recording enamel defects. The prevalence of DDE of any type was 40.2% in primary dentition and 52% in permanent dentition (p<0.033). Of the 31,820 primary and permanent teeth examined in the study, 699 (4.1%) primary and 1,232 (8.3%) permanent teeth had some form of DDE. Diffuse opacity was the most common type of DDE observed in primary teeth, and demarcated opacity in the permanent teeth. Enamel hypoplasia was the least prevalent defect in both dentition types. The study population showed a high prevalence of DDE in primary as well as in permanent dentition, reflecting the current increasing trend of this condition, which should be considered as a significant public health problem.

THE SOURCES, FATE AND HAZARDS OF MUTAGENS IN SURFACE WATERS

EPA Science Inventory

A variety of industrial, domestic and agricultural wastes are discharged into rivers, lakes, streams, and estuaries. In some instances, these wastes contain substances that are capable I of permanently altering the genetic material of exposed organisms (i.e., they are mutagens). ...

Large gap magnetic suspension system

NASA Technical Reports Server (NTRS)

Abdelsalam, Moustafa K.; Eyssa, Y. M.

1991-01-01

The design of a large gap magnetic suspension system is discussed. Some of the topics covered include: the system configuration, permanent magnet material, levitation magnet system, superconducting magnets, resistive magnets, superconducting levitation coils, resistive levitation coils, levitation magnet system, and the nitrogen cooled magnet system.

Development of permanent magnet MnAlC/polymer composites and flexible filament for bonding and 3D-printing technologies

PubMed Central

Rial, Javier; de Vicente, Javier; Skårman, Björn; Vidarsson, Hilmar; Larsson, Per-Olof

2018-01-01

Abstract Searching for high-performance permanent magnets components with no limitation in shape and dimensions is highly desired to overcome the present design and manufacturing restrictions, which affect the efficiency of the final devices in energy, automotive and aerospace sectors. Advanced 3D-printing of composite materials and related technologies is an incipient route to achieve functional structures avoiding the limitations of traditional manufacturing. Gas-atomized MnAlC particles combined with polymer have been used in this work for fabricating scalable rare earth-free permanent magnet composites and extruded flexible filaments with continuous length exceeding 10 m. Solution casting has been used to synthesize homogeneous composites with tuned particles content, made of a polyethylene (PE) matrix embedding quasi-spherical particles of the ferromagnetic τ-MnAlC phase. A maximum filling factor of 86.5 and 72.3% has been obtained for the composite and the filament after extrusion, respectively. The magnetic measurements reveal no deterioration of the properties of the MnAlC particles after the composite synthesis and filament extrusion. The produced MnAlC/PE materials will serve as precursors for an efficient and scalable design and fabrication of end-products by different processing techniques (polymerized cold-compacted magnets and 3D-printing, respectively) in view of technological applications (from micro electromechanical systems to energy and transport applications). PMID:29887921

Development of permanent magnet MnAlC/polymer composites and flexible filament for bonding and 3D-printing technologies.

PubMed

Palmero, Ester M; Rial, Javier; de Vicente, Javier; Camarero, Julio; Skårman, Björn; Vidarsson, Hilmar; Larsson, Per-Olof; Bollero, Alberto

2018-01-01

Searching for high-performance permanent magnets components with no limitation in shape and dimensions is highly desired to overcome the present design and manufacturing restrictions, which affect the efficiency of the final devices in energy, automotive and aerospace sectors. Advanced 3D-printing of composite materials and related technologies is an incipient route to achieve functional structures avoiding the limitations of traditional manufacturing. Gas-atomized MnAlC particles combined with polymer have been used in this work for fabricating scalable rare earth-free permanent magnet composites and extruded flexible filaments with continuous length exceeding 10 m. Solution casting has been used to synthesize homogeneous composites with tuned particles content, made of a polyethylene (PE) matrix embedding quasi-spherical particles of the ferromagnetic τ -MnAlC phase. A maximum filling factor of 86.5 and 72.3% has been obtained for the composite and the filament after extrusion, respectively. The magnetic measurements reveal no deterioration of the properties of the MnAlC particles after the composite synthesis and filament extrusion. The produced MnAlC/PE materials will serve as precursors for an efficient and scalable design and fabrication of end-products by different processing techniques (polymerized cold-compacted magnets and 3D-printing, respectively) in view of technological applications (from micro electromechanical systems to energy and transport applications).

Prevalence and factors affecting use of long acting and permanent contraceptive methods in Jinka town, Southern Ethiopia: a cross sectional study.

PubMed

Mekonnen, Getachew; Enquselassie, Fikre; Tesfaye, Gezahegn; Semahegn, Agumasie

2014-01-01

In Ethiopia, knowledge of contraceptive methods is high though there is low contraceptive prevalence rate. This study was aimed to assess prevalence and associated factors of long acting and permanent contraceptive methods in Jinka town, southern Ethiopia. Community based cross sectional survey was conducted to assess the prevalence and factors affecting long acting and permanent methods of contraceptives utilization from March to April 2008. Eight hundred child bearing age women were participated in the quantitative study and 32 purposively selected focus group discussants were participated in the qualitative study. Face to face interview was used for data collection. Data were analyzed by SPSS version 13.0 statistical software. Descriptive statistics and logistic regression were computed to analyze the data. The prevalence of long acting and permanent contraceptive method was 7.3%. Three fourth (76.1%) of the women have ever heard about implants and implant 28 (50%) were the most widely used method. Almost two third of women had intention to use long acting and permanent methods. Knowledge of contraceptive and age of women have significant association with the use of long acting and permanent contraceptive methods. The overall prevalence of long acting and permanent contraceptive method was low. Knowledge of contraceptive and age of women have significant association with use of long acting and permanent contraceptive. Extensive health information should be provided.

High trapped fields in bulk YBCO superconductors

NASA Astrophysics Data System (ADS)

Fuchs, Günter; Gruss, Stefan; Krabbes, Gernot; Schätzle, Peter; Verges, Peter; Müller, Karl-Hartmut; Fink, Jörg; Schultz, Ludwig

The trapped field properties of bulk melt-textured YBCO material were investigated at different temperatures. In the temperature range of liquid nitrogen, maximum trapped fields of 1.1 T were found at 77 K by doping of YBCO with small amounts of zinc. The improved pinning of zinc-doped YBa2Cu3O7-x (YBCO) results in a pronounced peak effect in the field dependence of the critical current density. the trapped field at lower temperatures increases due to the increasing critical current density, however, at temperatures around 50 K cracking of the material is observed which is exposed to considerably tensile stresses due to Lorentz forces. Very high trapped fields up to 14.4 T were achieved at 22.5 K for a YBCO disk pair by the addition of silver improving the tensile strength of YBCO and by using a bandage made of a steel tube. The steel tube produces a compressive stress on YBCO after cooling down from 300 K to the measuring temperature, which is due to the higher coeeficient of thermal expansion of steel compared with that of YBCO in the a,b plane. The application of superconducting permanent magnets with trapped fields of 10 T and more in superconducting bearings would allow to obtain very high levitation pressures up to 2500 N/cm2 which is two orders of magnitude higher than the levitation pressure achievable in superconducting bearings with conventional permanent magnets. The most important problem for the application of superconducting permanent magnets is the magnetizing procedure of the YBCO material. Results of magnetizing YBCO disks by using of pulsed magnetic fields will be presented.

Performance Evaluation and Improving Mechanisms of Diatomite-Modified Asphalt Mixture

PubMed Central

Yang, Chao; Xie, Jun; Zhou, Xiaojun; Liu, Quantao; Pang, Ling

2018-01-01

Diatomite is an inorganic natural resource in large reserve. This study consists of two phases to evaluate the effects of diatomite on asphalt mixtures. In the first phase, we characterized the diatomite in terms of mineralogical properties, chemical compositions, particle size distribution, mesoporous distribution, morphology, and IR spectra. In the second phase, road performances, referring to the permanent deformation, crack, fatigue, and moisture resistance, of asphalt mixtures with diatomite were investigated. The characterization of diatomite exhibits that it is a porous material with high SiO2 content and large specific surface area. It contributes to asphalt absorption and therefore leads to bonding enhancement between asphalt and aggregate. However, physical absorption instead of chemical reaction occurs according to the results of FTIR. The resistance of asphalt mixtures with diatomite to permanent deformation and moisture are superior to those of the control mixtures. But, the addition of diatomite does not help to improve the crack and fatigue resistance of asphalt mixture. PMID:29702579

Assessment of the 18-month permanence of onlay tip cartilage grafts following rhinoplasty.

PubMed

Persichetti, Paolo; Simone, Pierfranco; Carusi, Carlo

2013-09-01

Augmentation rhinoplasty requires addition of materials of various natures to reshape the nasal pyramid. Onlay tip grafts are single or multilayered grafts placed horizontally over the alar domes. The aim of the present study was to assess the 18-month permanence of onlay septal cartilage grafts. Twenty-eight patients underwent rhinoplasty with onlay tip cartilage graft, between June 2008 and November 2008 at the Campus Bio-Medico University in Rome, Italy. They were reviewed and photographed 6 months and 18 months postoperatively. Comparison of 6-month and 18-month postoperative pictures was performed with Adobe Photoshop CS. Measurements on pictures were taken with AutoCAD. Comparison of photographs showed no visible difference in nasal tip projection. Comparison of the measurements of tip projection showed a mean reduction of 0.06 mm (0.19%). Considerable stability of nasal tip projection after rhinoplasty with onlay tip grafts was observed postoperatively. Comparison of standardised digital photographs is a valid procedure to assess contour alterations of various anatomical structures after plastic surgery.

Performance Evaluation and Improving Mechanisms of Diatomite-Modified Asphalt Mixture.

PubMed

Yang, Chao; Xie, Jun; Zhou, Xiaojun; Liu, Quantao; Pang, Ling

2018-04-27

Diatomite is an inorganic natural resource in large reserve. This study consists of two phases to evaluate the effects of diatomite on asphalt mixtures. In the first phase, we characterized the diatomite in terms of mineralogical properties, chemical compositions, particle size distribution, mesoporous distribution, morphology, and IR spectra. In the second phase, road performances, referring to the permanent deformation, crack, fatigue, and moisture resistance, of asphalt mixtures with diatomite were investigated. The characterization of diatomite exhibits that it is a porous material with high SiO₂ content and large specific surface area. It contributes to asphalt absorption and therefore leads to bonding enhancement between asphalt and aggregate. However, physical absorption instead of chemical reaction occurs according to the results of FTIR. The resistance of asphalt mixtures with diatomite to permanent deformation and moisture are superior to those of the control mixtures. But, the addition of diatomite does not help to improve the crack and fatigue resistance of asphalt mixture.

Development and Implementation of the National Test Facility (NaTeF) for Fuels and Propulsion

DTIC Science & Technology

2013-10-01

permanent indentation. This equipment is used in the Materials Laboratory to determine hardness in polymers, elastomers, and rubbers , characteristics...impacted by exposure to synthetic fuels was the nitrile rubber , one of the materials selected for this research. Further research found a relationship...Similarly, as the molecular weight decreased, the volume swell increased. Therefore, it is indicated that the greatest swell in nitrile rubber will be

A Proposal for the Establishment of a Center for Advanced Composite Materials Research

DTIC Science & Technology

1992-03-01

materials. We were able to synthesize comb-shaped self-ordering polymers in which molecular teeth were functionalized at their termini. These chemical...layers were most likely transferred with phenolic functional groups exposed on the outer surface. For the fibers coated with polymer, contact angle...cured epoxy matrix. A striking result was observed, namely, the permanent birefringence obtained with coated fibers is 1.8 times greater than the one

Parametric estimation for reinforced concrete relief shelter for Aceh cases

NASA Astrophysics Data System (ADS)

Atthaillah; Saputra, Eri; Iqbal, Muhammad

2018-05-01

This paper was a work in progress (WIP) to discover a rapid parametric framework for post-disaster permanent shelter’s materials estimation. The intended shelters were reinforced concrete construction with bricks as its wall. Inevitably, in post-disaster cases, design variations were needed to help suited victims condition. It seemed impossible to satisfy a beneficiary with a satisfactory design utilizing the conventional method. This study offered a parametric framework to overcome slow construction-materials estimation issue against design variations. Further, this work integrated parametric tool, which was Grasshopper to establish algorithms that simultaneously model, visualize, calculate and write the calculated data to a spreadsheet in a real-time. Some customized Grasshopper components were created using GHPython scripting for a more optimized algorithm. The result from this study was a partial framework that successfully performed modeling, visualization, calculation and writing the calculated data simultaneously. It meant design alterations did not escalate time needed for modeling, visualization, and material estimation. Further, the future development of the parametric framework will be made open source.

Relationships Between Solidification Parameters in A319 Aluminum Alloy

NASA Astrophysics Data System (ADS)

Vandersluis, E.; Ravindran, C.

2018-03-01

The design of high-performance materials depends on a comprehensive understanding of the alloy-specific relationships between solidification and properties. However, the inconsistent use of a particular solidification parameter for presenting materials characterization in the literature impedes inter-study comparability and the interpretation of findings. Therefore, there is a need for accurate expressions relating the solidification parameters for each alloy. In this study, A319 aluminum alloy castings were produced in a permanent mold with various preheating temperatures in order to control metal cooling. Analysis of the cooling curve for each casting enabled the identification of its liquidus, Al-Si eutectic, and solidus temperatures and times. These values led to the calculation of the primary solidification rate, total solidification rate, primary solidification time, and local solidification time for each casting, which were related to each other as well as to the average casting SDAS and material hardness. Expressions for each of their correlations have been presented with high coefficients of determination, which will aid in microstructural prediction and casting design.

Electromagnetic Interference Behavior of Multiwall Carbon Nanotubes and Carbon Nanofibers Composites Under Fatigue

DTIC Science & Technology

2012-03-01

introducing conductive metallic materials onto or into the polymer composite. The earlier process steps included metallic paint coating, insertion......onboard from critical data loss to permanent damage. The ionized radiation strips electrons from atoms in the space plasma, creating charged

30 CFR 75.333 - Ventilation controls.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Radiant Heat Energy Source.” This publication is incorporated by reference and may be inspected at any... partitions, permanent stoppings, and regulators include concrete, concrete block, brick, cinder block, tile..., “Standard Test Method for Surface Flammability of Materials Using A Radiant Heat Energy Source.” This...

30 CFR 75.333 - Ventilation controls.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Radiant Heat Energy Source.” This publication is incorporated by reference and may be inspected at any... partitions, permanent stoppings, and regulators include concrete, concrete block, brick, cinder block, tile..., “Standard Test Method for Surface Flammability of Materials Using A Radiant Heat Energy Source.” This...

Demonstrating the Curie Temperature in the Classroom

ERIC Educational Resources Information Center

Williams, David; Banks, Octavia; Eichmeyer, Livia; Wu, Cherrin

2018-01-01

Recent GCSE and IGCSE specifications include reference to both permanent and induced magnetism, giving the opportunity for novel classroom demonstrations based on ferromagnetism and paramagnetism, and the transition between these phases. Ferromagnetic materials lose their magnetism if raised above their Curie Temperature, a specific temperature…

CCD imaging sensors

NASA Technical Reports Server (NTRS)

Janesick, James R. (Inventor); Elliott, Stythe T. (Inventor)

1989-01-01

A method for promoting quantum efficiency (QE) of a CCD imaging sensor for UV, far UV and low energy x-ray wavelengths by overthinning the back side beyond the interface between the substrate and the photosensitive semiconductor material, and flooding the back side with UV prior to using the sensor for imaging. This UV flooding promotes an accumulation layer of positive states in the oxide film over the thinned sensor to greatly increase QE for either frontside or backside illumination. A permanent or semipermanent image (analog information) may be stored in a frontside SiO.sub.2 layer over the photosensitive semiconductor material using implanted ions for a permanent storage and intense photon radiation for a semipermanent storage. To read out this stored information, the gate potential of the CCD is biased more negative than that used for normal imaging, and excess charge current thus produced through the oxide is integrated in the pixel wells for subsequent readout by charge transfer from well to well in the usual manner.

On-the-fly machine-learning for high-throughput experiments: search for rare-earth-free permanent magnets

PubMed Central

Kusne, Aaron Gilad; Gao, Tieren; Mehta, Apurva; Ke, Liqin; Nguyen, Manh Cuong; Ho, Kai-Ming; Antropov, Vladimir; Wang, Cai-Zhuang; Kramer, Matthew J.; Long, Christian; Takeuchi, Ichiro

2014-01-01

Advanced materials characterization techniques with ever-growing data acquisition speed and storage capabilities represent a challenge in modern materials science, and new procedures to quickly assess and analyze the data are needed. Machine learning approaches are effective in reducing the complexity of data and rapidly homing in on the underlying trend in multi-dimensional data. Here, we show that by employing an algorithm called the mean shift theory to a large amount of diffraction data in high-throughput experimentation, one can streamline the process of delineating the structural evolution across compositional variations mapped on combinatorial libraries with minimal computational cost. Data collected at a synchrotron beamline are analyzed on the fly, and by integrating experimental data with the inorganic crystal structure database (ICSD), we can substantially enhance the accuracy in classifying the structural phases across ternary phase spaces. We have used this approach to identify a novel magnetic phase with enhanced magnetic anisotropy which is a candidate for rare-earth free permanent magnet. PMID:25220062

Application of textured YBCO bulks with artificial holes for superconducting magnetic bearing

NASA Astrophysics Data System (ADS)

Dias, D. H. N.; Sotelo, G. G.; Moysés, L. A.; Telles, L. G. T.; Bernstein, P.; Kenfaui, D.; Aburas, M.; Chaud, X.; Noudem, J. G.

2015-07-01

The levitation force between a superconductor and a permanent magnet has been investigated for the development of superconducting magnetic bearings (SMBs). Depending on the proposed application, the SMBs can be arranged with two kinds of symmetries: rotational or linear. The SMBs present passive operation, low level of noise and no friction, but they need a cooling system for their operation. Nowadays the cooling problem may be easily solved by the use of a commercial cryocooler. The levitation force of SMBs is directly related to the quality of the superconductor material (which depends on its critical current density) and the permanent magnet arrangement. Also, research about the YBa2Cu3Ox (Y123) bulk materials has shown that artificial holes enhance the superconducting properties, in particular the magnetic trapped field. In this context, this work proposes the investigation of the levitation force of a bulk Y123 sample with multiple holes and the comparison of its performances with those of conventional plain Y123 superconductors.

Tessellated permanent magnet circuits for flow-through, open gradient separations of weakly magnetic materials

PubMed Central

Moore, Lee R.; Williams, P. Stephen; Chalmers, Jeffrey J.; Zborowski, Maciej

2017-01-01

Emerging microfluidic-based cell assays favor label-free red blood cell (RBC) depletion. Magnetic separation of RBC is possible because of the paramagnetism of deoxygenated hemoglobin but the process is slow for open-gradient field configurations. In order to increase the throughput, periodic arrangements of the unit magnets were considered, consisting of commercially available Nd-Fe-B permanent magnets and soft steel flux return pieces. The magnet design is uniquely suitable for multiplexing by magnet tessellation, here meaning the tiling of the magnet assembly cross-sectional plane by periodic repetition of the magnet and the flow channel shapes. The periodic pattern of magnet magnetizations allows a reduction of the magnetic material per channel with minimal distortion of the field cylindrical symmetry inside the magnet apertures. A number of such magnet patterns are investigated for separator performance, size and economy with the goal of designing an open-gradient magnetic separator capable of reducing the RBC number concentration a hundred-fold in 1 mL whole blood per hour. PMID:29104346

Tessellated permanent magnet circuits for flow-through, open gradient separations of weakly magnetic materials.

PubMed

Moore, Lee R; Williams, P Stephen; Chalmers, Jeffrey J; Zborowski, Maciej

2017-04-01

Emerging microfluidic-based cell assays favor label-free red blood cell (RBC) depletion. Magnetic separation of RBC is possible because of the paramagnetism of deoxygenated hemoglobin but the process is slow for open-gradient field configurations. In order to increase the throughput, periodic arrangements of the unit magnets were considered, consisting of commercially available Nd-Fe-B permanent magnets and soft steel flux return pieces. The magnet design is uniquely suitable for multiplexing by magnet tessellation, here meaning the tiling of the magnet assembly cross-sectional plane by periodic repetition of the magnet and the flow channel shapes. The periodic pattern of magnet magnetizations allows a reduction of the magnetic material per channel with minimal distortion of the field cylindrical symmetry inside the magnet apertures. A number of such magnet patterns are investigated for separator performance, size and economy with the goal of designing an open-gradient magnetic separator capable of reducing the RBC number concentration a hundred-fold in 1 mL whole blood per hour.

Comparative study of solid waste management system based on building types in Palembang city

NASA Astrophysics Data System (ADS)

Jimmyanto, Hendrik; Dahlan, Hatta; Zahri, Imron

2017-11-01

Most of the solid waste generation sources come from housing activities. The types of house buildings located in the Palembang is a traditional building which made from wood construction and a permanent house which made from concrete construction. The aim of this study is to calculate the amount of waste generation and to study the community behavior in waste management. The research used an observation and questionnaires that took place in 3 location of the traditional housing and 3 location of the permanent housing with 20 respondents for each location. The results showed that the waste generation in the traditional housing was 1.51 liters/person/day and the permanent housing was 1.63 liters/person/day. The collecting system in traditional housing was taken by the garbage cart every 1 days, while in permanent housing was taken by motorcycle, pick-up car, or dump truck every 1 or 2 days. The questionnaire results showed that 96,67% of the traditional housing and 91,67% of the permanent housing disposed of the waste in a mix condition. Amount of 6,67 % from the traditional housing and 0% of permanent housing managed their waste into compost. Amount of 15 % from traditional housing and 3,33% of permanent housing sold their waste. Based on the results, it can be concluded that the permanent housing has the largest number of waste generation and the people in traditional housing had a tendency to manage the waste better than the permanent housing.

Evaluation of the root and canal morphology of mandibular permanent molars in a south-eastern Turkish population using cone-beam computed tomography

PubMed Central

Nur, Bilge Gulsum; Ok, Evren; Altunsoy, Mustafa; Aglarci, Osman Sami; Colak, Mehmet; Gungor, Enes

2014-01-01

Objective: The aim of this retrospective study was to determine the root and canal morphology of the mandibular first and second permanent molars in a Turkish population using cone-beam computed tomography (CBCT). Materials and Methods: CBCT images of mandibular first (n = 966) and second molar (n = 1165) teeth from 850 Turkish patients were evaluated. The root canal configurations were classified according to the method of Vertucci. The data were analyzed by Pearson's Chi-square test. Results: The majority of mandibular molars were two rooted with three canals; however, three roots were identified in 0.05% of the first molars and 0.01% of the second molars, and 100% of the additional root canals were of type I configuration. Mesial roots had more complex canal systems with more than one canal, whereas most distal roots had a type I configuration. Conclusions: Within the limitations of this study, it can be concluded that CBCT scanning provides supplemental information about the root canal configurations of mandibular molars in a Turkish population. This study may help clinicians in the root canal treatment of mandibular molars. PMID:24966763

Likelihood of Entanglement when Materials are Dropped Vertically onto a Rotating PTO Knuckle.

PubMed

Schwab, Charles V; Rempe, Isaac J

2017-11-20

Power take-off (PTO) is a common method of transferring power from a tractor to a towed piece of machinery. The PTO is also a well-documented cause of severe and often permanent disabling injuries to farm operators. The physical conditions that cause entanglements are not well established. Several studies have explored the parameters of PTO entanglements as materials have been drawn across a rotating PTO knuckle to test for entanglement probability. The objective of this study was to determine probability of entanglement when materials are dropped vertically onto a PTO knuckle spinning at 540 rpm. A total of 360 randomized trials were conducted with ten replications for each of the six positions (center of yoke, edge of yoke rotating downward, edge of yoke rotating upward, center of cross, edge of cross rotating downward, and edge of cross rotating upward) and six different materials (woven cotton athletic shoe lace, cotton workboot lace, leather workboot lace, cotton twine, denim strip, and Tyvek strip). Not a single entanglement was recorded. Dramatic high-speed video imagery authenticated the material's motion and path as it interacted with the rotating PTO knuckle. Copyright© by the American Society of Agricultural Engineers.

Direct 4D printing via active composite materials.

PubMed

Ding, Zhen; Yuan, Chao; Peng, Xirui; Wang, Tiejun; Qi, H Jerry; Dunn, Martin L

2017-04-01

We describe an approach to print composite polymers in high-resolution three-dimensional (3D) architectures that can be rapidly transformed to a new permanent configuration directly by heating. The permanent shape of a component results from the programmed time evolution of the printed shape upon heating via the design of the architecture and process parameters of a composite consisting of a glassy shape memory polymer and an elastomer that is programmed with a built-in compressive strain during photopolymerization. Upon heating, the shape memory polymer softens, releases the constraint on the strained elastomer, and allows the object to transform into a new permanent shape, which can then be reprogrammed into multiple subsequent shapes. Our key advance, the markedly simplified creation of high-resolution complex 3D reprogrammable structures, promises to enable myriad applications across domains, including medical technology, aerospace, and consumer products, and even suggests a new paradigm in product design, where components are simultaneously designed to inhabit multiple configurations during service.

Magnetic superelevation design of Halbach permanent magnet guideway for high-temperature superconducting maglev

NASA Astrophysics Data System (ADS)

Lei, Wuyang; Qian, Nan; Zheng, Jun; Huang, Huan; Zhang, Ya; Deng, Zigang

2017-07-01

To improve the curve negotiating ability of high-temperature superconducting (HTS) maglev system, a special structure of magnetic superelevation for double-pole Halbach permanent magnet guideway (PMG) was designed. The most significant feature of this design is the asymmetrical PMG that forms a slanting magnetic field without affecting the smoothness of the PMG surface. When HTS maglev vehicle runs through curves with magnetic superelevation, the vehicle will slant due to asymmetry in magnetic field and the flux-pinning effect of onboard HTS bulks. At the same time, one component of the levitation force provides a part of the centripetal force that reduces lateral acceleration of the vehicle and thus enhances its curve negotiating ability. Furthermore, the slant angle of magnetic superelevation can be adjusted by changing the materials and the thickness of the added permanent magnets. This magnetic superelevation method, together with orographic uplift, can be applied to different requirements of PMG designs. Besides, the applicability of this method would benefit future development of high-speed HTS maglev system.

Direct 4D printing via active composite materials

PubMed Central

Ding, Zhen; Yuan, Chao; Peng, Xirui; Wang, Tiejun; Qi, H. Jerry; Dunn, Martin L.

2017-01-01

We describe an approach to print composite polymers in high-resolution three-dimensional (3D) architectures that can be rapidly transformed to a new permanent configuration directly by heating. The permanent shape of a component results from the programmed time evolution of the printed shape upon heating via the design of the architecture and process parameters of a composite consisting of a glassy shape memory polymer and an elastomer that is programmed with a built-in compressive strain during photopolymerization. Upon heating, the shape memory polymer softens, releases the constraint on the strained elastomer, and allows the object to transform into a new permanent shape, which can then be reprogrammed into multiple subsequent shapes. Our key advance, the markedly simplified creation of high-resolution complex 3D reprogrammable structures, promises to enable myriad applications across domains, including medical technology, aerospace, and consumer products, and even suggests a new paradigm in product design, where components are simultaneously designed to inhabit multiple configurations during service. PMID:28439560

Method for charging a hydrogen getter

DOEpatents

Tracy, C.E.; Keyser, M.A.; Benson, D.K.

1998-09-15

A method for charging a sample of either a permanent or reversible getter material with a high concentration of hydrogen while maintaining a base pressure below 10{sup {minus}4} torr at room temperature involves placing the sample of hydrogen getter material in a chamber, activating the sample of hydrogen getter material, overcharging the sample of getter material through conventional charging techniques to a high concentration of hydrogen, and then subjecting the sample of getter material to a low temperature vacuum bake-out process. Application of the method results in a reversible hydrogen getter which is highly charged to maximum capacities of hydrogen and which concurrently exhibits minimum hydrogen vapor pressures at room temperatures. 9 figs.

Seal material development test program

NASA Technical Reports Server (NTRS)

1971-01-01

A program designed to characterize an experimental fluoroelastomer material designated AF-E-124D, is examined. Tests conducted include liquid nitrogen load compression tests, flexure tests and valve seal tests, ambient and elevated temperature compression set tests, and cleaning and flushing fluid exposure tests. The results of these tests indicate the AF-E-124D is a good choice for a cryogenic seal, since it exhibits good low temperature sealing characteristics and resistance to permanent set. The status of this material as an experimental fluorelastomer is stressed and recommended. Activity includes definition and control of critical processing to ensure consistent material properties. Design, fabrication and test of this and other materials is recommended in valve and static seal applications.

Effect of Chemical Treatments on Flax Fibre Reinforced Polypropylene Composites on Tensile and Dome Forming Behaviour

PubMed Central

Wang, Wentian; Lowe, Adrian; Kalyanasundaram, Shankar

2015-01-01

Tensile tests were performed on two different natural fibre composites (same constituent material, similar fibre fraction and thickness but different weave structure) to determine changes in mechanical properties caused by various aqueous chemical treatments and whether any permanent changes remain on drying. Scanning electronic microscopic examinations suggested that flax fibres and the flax/polypropylene interface were affected by the treatments resulting in tensile property variations. The ductility of natural fibre composites was improved significantly under wet condition and mechanical properties (elongation-to-failure, stiffness and strength) can almost retain back to pre-treated levels when dried from wet condition. Preheating is usually required to improve the formability of material in rapid forming, and the chemical treatments performed in this study were far more effective than preheating. The major breakthrough in improving the formability of natural fibre composites can aid in rapid forming of this class of material system. PMID:25789505

Current induced polycrystalline-to-crystalline transformation in vanadium dioxide nanowires

PubMed Central

Jeong, Junho; Yong, Zheng; Joushaghani, Arash; Tsukernik, Alexander; Paradis, Suzanne; Alain, David; Poon, Joyce K. S.

2016-01-01

Vanadium dioxide (VO2) exhibits a reversible insulator-metal phase transition that is of significant interest in energy-efficient nanoelectronic and nanophotonic devices. In these applications, crystalline materials are usually preferred for their superior electrical transport characteristics as well as spatial homogeneity and low surface roughness over the device area for reduced scattering. Here, we show applied electrical currents can induce a permanent reconfiguration of polycrystalline VO2 nanowires into crystalline nanowires, resulting in a dramatically reduced hysteresis across the phase transition and reduced resistivity. Low currents below 3 mA were sufficient to cause the local temperature in the VO2 to reach about 1780 K to activate the irreversible polycrystalline-to-crystalline transformation. The crystallinity was confirmed by electron microscopy and diffraction analyses. This simple yet localized post-processing of insulator-metal phase transition materials may enable new methods of studying and fabricating nanoscale structures and devices formed from these materials. PMID:27892519

A high-throughput exploration of magnetic materials by using structure predicting methods

NASA Astrophysics Data System (ADS)

Arapan, S.; Nieves, P.; Cuesta-López, S.

2018-02-01

We study the capability of a structure predicting method based on genetic/evolutionary algorithm for a high-throughput exploration of magnetic materials. We use the USPEX and VASP codes to predict stable and generate low-energy meta-stable structures for a set of representative magnetic structures comprising intermetallic alloys, oxides, interstitial compounds, and systems containing rare-earths elements, and for both types of ferromagnetic and antiferromagnetic ordering. We have modified the interface between USPEX and VASP codes to improve the performance of structural optimization as well as to perform calculations in a high-throughput manner. We show that exploring the structure phase space with a structure predicting technique reveals large sets of low-energy metastable structures, which not only improve currently exiting databases, but also may provide understanding and solutions to stabilize and synthesize magnetic materials suitable for permanent magnet applications.

Molecular simulation study of the competitive adsorption of H2O and CO2 in zeolite 13X.

PubMed

Joos, Lennart; Swisher, Joseph A; Smit, Berend

2013-12-23

The presence of H2O in postcombustion gas streams is an important technical issue for deploying CO2-selective adsorbents. Because of its permanent dipole, H2O can interact strongly with materials where the selectivity for CO2 is a consequence of its quadrupole interacting with charges in the material. We performed molecular simulations to model the adsorption of pure H2O and CO2 as well as H2O/CO2 mixtures in 13X, a popular zeolite for CO2 capture processes that is commercially available. The simulations show that H2O reduces the capacity of these materials for adsorbing CO2 by an order of magnitude and that at the partial pressures of H2O relevant for postcombustion capture, 13X will be essentially saturated with H2O .

PIM-1 as a Solution-Processable “Molecular Basket” for CO 2 Capture from Dilute Sources

DOE PAGES

Pang, Simon H.; Jue, Melinda L.; Leisen, Johannes; ...

2015-12-07

Here, rising atmospheric CO 2 levels have triggered recent research into the science of amine materials supported on hard, porous materials such as mesoporous silica or alumina. While such materials can give high CO 2 uptakes and good sorption kinetics, they are difficult to utilize in practical applications due to difficulty in contacting large volumes of CO 2-laden gases with powder materials without significant pressure drops or sorbent attrition. Here, we describe a simple approach based on the impregnation of a permanently microporous polymer, PIM-1, with poly(ethylene imine) (PEI), removing the need for use of the hard oxide. PEI/PIM-1 compositesmore » demonstrate comparable performance to more traditionally studied oxide sorbents, with the benefit that PIM-1 is soluble in common solvents, making it eminently more viable for processing into morphologies that can facilitate heat and mass transfer and fabrication into low pressure drop contactors. In addition to adsorption studies performed on a variety of PEI/PIM-1 architectures, spin diffusion NMR studies were performed to suggest that PEI is well-dispersed within the PIM-1, allowing for rapid CO 2 adsorption.« less

An in vitro assessment of type, position and incidence of isthmus in human permanent molars

PubMed Central

de LIMA, Fernando José Camello; MONTAGNER, Francisco; JACINTO, Rogério Castilho; AMBROSANO, Glaucia Maria Bovi; GOMES, Brenda Paula Figueiredo de Almeida

2014-01-01

Root canal anatomical complexities, such as isthmus, may limit the action of the endodontic instruments, irrigant solutions and intracanal medications, leading to endodontic treatment failure. Objectives This in vitro study assessed the type, position and incidence of isthmus in human permanent molars. Material and Methods One hundred and twenty eight upper and lower first and second permanent molars were analyzed. The roots were embedded in transparent resin, and then split at different distances from the apex (1.0-2.5-4.0-5.5-7.0 mm). Following the sample examination in stereomicroscope, the data were submitted to chi-square statistical test at a 5% significance level. Results The highest isthmus incidence was at 7.0 mm from the root apex in all samples, except the distal root of lower molars (at 5.5 mm). In upper and lower molars, type V (complete isthmus with a continuous opening between the two main root canals) was the most common classification of isthmus (28.8%). In the mesial root of first and second mandibular molars, type IV had the highest incidence (36% and 23.9%, respectively). Conclusion It was concluded that isthmus was widely found in flat roots, with a low percentage in areas close to the apex. In upper and lower molars, these structures were most frequently found at 7 mm from the apex. PMID:25141198

Radioactive waste storage issues

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

Kunz, Daniel E.

1994-08-15

In the United States we generate greater than 500 million tons of toxic waste per year which pose a threat to human health and the environment. Some of the most toxic of these wastes are those that are radioactively contaminated. This thesis explores the need for permanent disposal facilities to isolate radioactive waste materials that are being stored temporarily, and therefore potentially unsafely, at generating facilities. Because of current controversies involving the interstate transfer of toxic waste, more states are restricting the flow of wastes into - their borders with the resultant outcome of requiring the management (storage and disposal)more » of wastes generated solely within a state`s boundary to remain there. The purpose of this project is to study nuclear waste storage issues and public perceptions of this important matter. Temporary storage at generating facilities is a cause for safety concerns and underscores, the need for the opening of permanent disposal sites. Political controversies and public concern are forcing states to look within their own borders to find solutions to this difficult problem. Permanent disposal or retrievable storage for radioactive waste may become a necessity in the near future in Colorado. Suitable areas that could support - a nuclear storage/disposal site need to be explored to make certain the health, safety and environment of our citizens now, and that of future generations, will be protected.« less

49 CFR 192.717 - Transmission lines: Permanent field repair of leaks.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) PIPELINE SAFETY TRANSPORTATION OF NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance... pipe in size. (4) If the leak is on a submerged offshore pipeline or submerged pipeline in inland...

Bottlenecks

ERIC Educational Resources Information Center

Grinstead, Robert R.

1972-01-01

Solid wastes that go at low cost into municipal landfills contain valuable raw materials which technology is not equipped to handle on a large scale. Identifying the key stumbling blocks may help divert the flow of wastes to useful purposes rather than into permanent burial sites. First of a two-part article. (BL)

75 FR 66316 - National Historical Publications and Records Commission Grants

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-28

... Office of Management and Budget (OMB) requirement to use Standard Form (SF) 425, Federal Financial Report... changes from the Office of Management and Budget; others proposed changes to eligible applicants and the... policy or to provide procedural details. Historical records means documentary material having permanent...

49 CFR 177.834 - General requirements.

Code of Federal Regulations, 2014 CFR

2014-10-01

... and Unloading § 177.834 General requirements. (a) Packages secured in a motor vehicle. Any package containing any hazardous material, not permanently attached to a motor vehicle, must be secured against... smoking while loading or unloading. Smoking on or about any motor vehicle while loading or unloading any...

49 CFR 177.834 - General requirements.

Code of Federal Regulations, 2012 CFR

2012-10-01

... and Unloading § 177.834 General requirements. (a) Packages secured in a motor vehicle. Any package containing any hazardous material, not permanently attached to a motor vehicle, must be secured against... smoking while loading or unloading. Smoking on or about any motor vehicle while loading or unloading any...

49 CFR 177.834 - General requirements.

Code of Federal Regulations, 2013 CFR

2013-10-01

... and Unloading § 177.834 General requirements. (a) Packages secured in a motor vehicle. Any package containing any hazardous material, not permanently attached to a motor vehicle, must be secured against... smoking while loading or unloading. Smoking on or about any motor vehicle while loading or unloading any...

[Investigation on source and dissemination way of knowledge on schistosomiasis prevention and control in population in Jingjiang City after transmission-interrupted].

PubMed

Wang, Ji-sheng; Chen, Jian-feng; Liu, Ya-hong; Song, Liang-liang

2016-02-01

To understand the source of knowledge on schistosomiasis prevention and control and the acceptable degree on different propagation patterns of population in Jingjiang City after schistosomiasis transmission-interrupted, so as to provide the evidence for the production of suitable materials for health education. The permanent residents, floating population as well as the primary school students in Grade 5 and 6 in riverside regions in Jingjiang City were selected as the investigation objects, the information propagation condition and the knowledge source, and the expected propagation patterns were investigated by questionnaires. The popularizing rates on the television, computer and mobile phone of the villagers were 99.81%, 84.16% and 87.78%, respectively. Both the two investigated schools had the independent TV network, broadcast and multimedia, and all the computer classroom could connected to Internet. The main sources on schistosomiasis control of permanent residents and floating population were folders and the exhibition board (62.0% and 40.5% respectively), the substantial material (42.0% and 33.5% respectively) and TV (40.5% and 36.0% respectively), while those of the students were video CD (100%), substantial material (99.5%) and folders and the exhibition boards (84.2%). The propagation ways with high acceptable degrees among the residents and floating population were substantial material, folders and the exhibition boards and short messages by mobile phone, while those among the students were video CD, substantial material, folders and the exhibition boards. The material on health education should be targeted to the demands of the different populations and their condition of information propagation, in addition, the Internet material should be developed and the communicational channels should be broaden.

A Cryogenic Magnetostrictive Actuator Using a Persistent High Temperature Superconducting Magnet. Part 1; Concept and Design

NASA Technical Reports Server (NTRS)

Horner, Garnett; Bromberg, Leslie; Teter, J. P.

2000-01-01

Cryogenic magnetostrictive materials, such as rare earth zinc crystals, offer high strains and high forces with minimally applied magnetic fields, making the material ideally suited for deformable optics applications. For cryogenic temperature applications the use of superconducting magnets offer the possibility of a persistent mode of operation, i.e., the magnetostrictive material will maintain a strain field without power. High temperature superconductors (HTS) are attractive options if the temperature of operation is higher than 10 degrees Kelvin (K) and below 77 K. However, HTS wires have constraints that limit the minimum radius of winding, and even if good wires can be produced, the technology for joining superconducting wires does not exist. In this paper, the design and capabilities of a rare earth zinc magnetostrictive actuator using bulk HTS is described. Bulk superconductors can be fabricated in the sizes required with excellent superconducting properties. Equivalent permanent magnets, made with this inexpensive material, are persistent, do not require a persistent switch as in HTS wires, and can be made very small. These devices are charged using a technique which is similar to the one used for charging permanent magnets, e.g., by driving them into saturation. A small normal conducting coil can be used for charging or discharging. Because of the magnetic field capability of the superconductor material, a very small amount of superconducting magnet material is needed to actuate the rare earth zinc. In this paper, several designs of actuators using YBCO and BSCCO 2212 superconducting materials are presented. Designs that include magnetic shielding to prevent interaction between adjacent actuators will also be described. Preliminary experimental results and comparison with theory for BSCCO 2212 with a magnetostrictive element will be discussed.

Electrical connector composite housing and method of making same

DOEpatents

Silva, Frank A.

1979-01-01

A sleeve-like insert of conductive elastomeric material of a type which serves as an internal shield in electrical connectors for connecting high voltage cables has an end portion folded upon itself, the enfolded portion being substantially permanently retained in its desired position by allowing insulative elastomeric material to fill apertures in the end portion and become bonded thereto in a void free manner, during molding of an insulating outer sleeve-like jacket about the insert.

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

Agnew, Douglas W.; DiMucci, Ida M.; Arroyave, Alejandra

A permanently porous, three-dimensional metal–organic material formed from zero-valent metal nodes is presented. Combination of ditopic m-terphenyl diisocyanide, [CNAr Mes2] 2, and the d 10 Ni(0) precursor Ni(COD) 2, produces a porous metal–organic material featuring tetrahedral [Ni(CNAr Mes2) 4] n structural sites. X-ray absorption spectroscopy provides firm evidence for the presence of Ni(0) centers, whereas gas-sorption and thermogravimetric analysis reveal the characteristics of a robust network with a microdomain N 2-adsorption profile.

Permanent and separable aerospace tubing/ fitting evaluation program, volume 1

NASA Technical Reports Server (NTRS)

Ursell, C. R.; Franz, C. R.

1975-01-01

The tube fitting evaluation program was conducted to develop a standard overall test program including methods, procedures, and equipment as well as recommended test sequences for qualifying fitting/tubing assemblies. The program consisted of testing the MS flareless (separable) fitting and utilizing the results as baseline data from which all other fittings will be evaluated. Five separable designs and five permanent designs were tested in three sizes with two types of tubing materials. The basic design requirements were 4,000 psi operating pressure within the temperature range of minus 65 F to plus 450 F while also being compatible with 21-6-9 and titanium 3Al-2.5V tubing alloys.

Axial force in a superconductor magnet journal bearing

NASA Astrophysics Data System (ADS)

Postrekhin, E.; Chong, Wang; Ki Bui, Ma; Chen, Quark; Chu, Wei-Kan

Using superconductors and magnets, a journal bearing could be made from a permanent magnet cylinder in a superconductor ring. We have assembled a prototype superconductor magnet journal bearing of this configuration, and investigated the behavior of the axial force that it can provide. We have put together a numerical model of the interaction between the permanent magnet and the superconductor that is capable of describing these experimental results semi-quantitatively. Combining direct experimental measurements and using the numerical models proposed, we have achieved a qualitative understanding of the behavior of the axial force and its relationship of to the dimensions of the magnet and material quality such as the homogeneity of the superconductor that constitute the bearing.

Coercivity degradation caused by inhomogeneous grain boundaries in sintered Nd-Fe-B permanent magnets

NASA Astrophysics Data System (ADS)

Chen, Hansheng; Yun, Fan; Qu, Jiangtao; Li, Yingfei; Cheng, Zhenxiang; Fang, Ruhao; Ye, Zhixiao; Ringer, Simon P.; Zheng, Rongkun

2018-05-01

Quantitative correlation between intrinsic coercivity and grain boundaries in three dimensions is critical to further improve the performance of sintered Nd-Fe-B permanent magnets. Here, we quantitatively reveal the local composition variation across and especially along grain boundaries using the powerful atomic-scale analysis technique known as atom probe tomography. We also estimate the saturation magnetization, magnetocrystalline anisotropy constant, and exchange stiffness of the grain boundaries on the basis of the experimentally determined structure and composition. Finally, using micromagnetic simulations, we quantify the intrinsic coercivity degradation caused by inhomogeneous grain boundaries. This approach can be applied to other magnetic materials for the analysis and optimization of magnetic properties.

Apical Closure in Apexification: A Review and Case Report of Apexification Treatment of an Immature Permanent Tooth with Biodentine.

PubMed

Vidal, Karla; Martin, Gabriela; Lozano, Oscar; Salas, Marco; Trigueros, Jaime; Aguilar, Gabriel

2016-05-01

Materials such as calcium hydroxide paste and mineral trioxide aggregate are used in apexification treatment of immature permanent teeth, but the search for improved materials with higher characteristics of biocompatibility results in different materials. Biodentine is a tricalcium silicate cement that possesses adequate handling characteristics and acceptable mechanical and bioactivity properties. This report describes the case of a 9-year-old boy who was referred to the Department of Dental Clinic of Querétaro Autonomous University of Mexico. One month prior the patient had suffered a dental trauma of his upper left central incisor and had been treated by another dentist. The clinical diagnosis was previously initiated therapy and symptomatic apical periodontitis. The treatment was apexification with Biodentine. At follow-ups performed at 3, 6, and 18 months after treatment the tooth was asymptomatic. The cone-beam computed tomography scan at 18-month postoperative follow-up revealed continuity of periodontal ligament space, absence of periapical rarefactions, and a thin layer of calcified tissue formed apical to the Biodentine barrier. On the basis of sealing ability and biocompatibility, apexification treatment with Biodentine was applied in the present case report. The favorable clinical and radiographic outcome in this case demonstrated that Biodentine may be an efficient alternative to the conventional apexification materials. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

The effect of surface grain reversal on the AC losses of sintered Nd-Fe-B permanent magnets

NASA Astrophysics Data System (ADS)

Moore, Martina; Roth, Stefan; Gebert, Annett; Schultz, Ludwig; Gutfleisch, Oliver

2015-02-01

Sintered Nd-Fe-B magnets are exposed to AC magnetic fields in many applications, e.g. in permanent magnet electric motors. We have measured the AC losses of sintered Nd-Fe-B magnets in a closed circuit arrangement using AC fields with root mean square-values up to 80 mT (peak amplitude 113 mT) over the frequency range 50 to 1000 Hz. Two magnet grades with different dysprosium content were investigated. Around the remanence point the low grade material (1.7 wt% Dy) showed significant hysteresis losses; whereas the losses in the high grade material (8.9 wt% Dy) were dominated by classical eddy currents. Kerr microscopy images revealed that the hysteresis losses measured for the low grade magnet can be mainly ascribed to grains at the sample surface with multiple domains. This was further confirmed when the high grade material was subsequently exposed to DC and AC magnetic fields. Here a larger number of surface grains with multiple domains are also present once the step in the demagnetization curve attributed to the surface grain reversal is reached and a rise in the measured hysteresis losses is evident. If in the low grade material the operating point is slightly offset from the remanence point, such that zero field is not bypassed, its AC losses can also be fairly well described with classical eddy current theory.

Preliminary design of a Primary Loop Pump Assembly (PLPA), using electromagnetic pumps

NASA Technical Reports Server (NTRS)

Moss, T. A.; Matlin, G.; Donelan, L.; Johnson, J. L.; Rowe, I.

1972-01-01

A preliminary design study of flight-type dc conduction-permanent magnetic, ac helical induction, and ac linear induction pumps for circulating 883 K (1130 F) NaK at 9.1 kg/sec (20 lb/sec) is described. Various electromagnetic pump geometrics are evaluated against hydraulic performance, and the effects of multiple windings and numbers of pumps per assembly on overall reliability were determined. The methods used in the electrical-hydraulic, stress, and thermal analysis are discussed, and the high temperature electrical materials selected for the application are listed.

Space station needs, attributes and architectural options study. Volume 5: Cost benefits and programmatic analyses

NASA Technical Reports Server (NTRS)

1983-01-01

The science, applications, commercial, U.S. national security and space operations missions that would require or be materially benefited by the availability of a permanent manned space station in low Earth orbit are considered. Space station attributes and capabilities which will be necessary to satisfy these mission requirements are identified. Emphasis is placed on the identification and validation of potential users, their requirements, and the benefits accruing to them from the existence of a space station, and the programmatic and cost implications of a space station program.

Experiences of the fairness of recruitment from unsuccessful applicants in the field of nursing.

PubMed

Kanerva, Anne; Lammintakanen, Johanna; Kivinen, Tuula

2010-04-01

The purpose of this study was to describe the experiences of unsuccessful applicants for permanent nursing positions with regard to the fairness of the recruitment process. The international shortage of recruits in nursing and the rapidly increasing number of nurses retiring implies new challenges for recruitment. The nurses' experiences of fairness affect the availability of nurses and the attractiveness of the organization. The recruitment process is approached through traditional organizational justice theories. The material was gathered from thematic interviews with 12 nurses who had applied for a permanent nursing position but were not selected. The material was analysed using theory-driven content analysis. The nurses felt differently about the result of the recruitment process. The experience of distributive justice alone was not significant in terms of the general sense of justice, since other dimensions of justice compensated for it. The effect of applicants' experiences of fair treatment in the recruitment process affected their future behaviour positively, negatively or not at all. and implications for nursing management It is crucial to recognize applicants' experiences of the fairness of the recruitment process, because unsuccessful applicants constitute a pool of potential new employees. Furthermore, applicants with different experiences cannot be seen as a homogenous group. For example, internal applicants with negative experiences pose challenges for nursing management with regard to retaining them in the organization.

Autogenous Metallic Pipe Leak Repair in Potable Water Systems.

PubMed

Tang, Min; Triantafyllidou, Simoni; Edwards, Marc A

2015-07-21

Copper and iron pipes have a remarkable capability for autogenous repair (self-repair) of leaks in potable water systems. Field studies revealed exemplars that metallic pipe leaks caused by nails, rocks, and erosion corrosion autogenously repaired, as confirmed in the laboratory experiments. This work demonstrated that 100% (N = 26) of 150 μm leaks contacting representative bulk potable water in copper pipes sealed autogenously via formation of corrosion precipitates at 20-40 psi, pH 3.0-11.0, and with upward and downward leak orientations. Similar leaks in carbon steel pipes at 20 psi self-repaired at pH 5.5 and 8.5, but two leaks did not self-repair permanently at pH 11.0 suggesting that water chemistry may control the durability of materials that seal the leaks and therefore the permanence of repair. Larger 400 μm holes in copper pipes had much lower (0-33%) success of self-repair at pH 3.0-11.0, whereas all 400 μm holes in carbon steel pipes at 20 psi self-repaired at pH 4.0-11.0. Pressure tests indicated that some of the repairs created at 20-40 psi ambient pressure could withstand more than 100 psi without failure. Autogenous repair has implications for understanding patterns of pipe failures, extending the lifetime of decaying infrastructure, and developing new plumbing materials.

A Comparative Study on Permanent Mold Cast and Powder Thixoforming 6061 Aluminum Alloy and Sicp/6061Al Composite: Microstructures and Mechanical Properties.

PubMed

Zhang, Xuezheng; Chen, Tijun; Qin, He; Wang, Chong

2016-05-24

Microstructural and mechanical characterization of 10 vol% SiC particles (SiC p ) reinforced 6061 Al-based composite fabricated by powder thixoforming (PTF) was investigated in comparison with the PTF and permanent mold cast (PMC) 6061 monolithic alloys. The results reveal that the microstructure of the PMC alloy consists of coarse and equiaxed α dendrites and interdendritic net-like eutectic phases. However, the microstructure of the PTF composite, similar to that of the PTF alloy, consists of near-spheroidal primary particles and intergranular secondarily solidified structures except SiC p , which are distributed in the secondarily solidified structures. The eutectics amount in the PTF materials is distinctly lower than that in the PMC alloy, and the microstructures of the former materials are quite compact while that of the latter alloy is porous. Therefore, the PTF alloy shows better tensile properties than the PMC alloy. Owing to the existence of the SiC reinforcing particles, the PTF composite attains an ultimate tensile strength and yield strength of 230 MPa and 128 MPa, representing an enhancement of 27.8% and 29.3% than those (180 MPa and 99 MPa) of the PTF alloy. A modified model based on three strengthening mechanisms was proposed to calculate the yield strength of the PTF composite. The obtained theoretical results were quite consistent with the experimental data.

An incremental analysis of a deep drawing steel’s material behaviour undergoing the predeformation using drawbeads

NASA Astrophysics Data System (ADS)

Schmid, H.; Suttner, S.; Merklein, M.

2017-09-01

Nowadays lightweight design in metal forming processes leads to complex deep drawing geometries, which can cause multiple damages. Therefore, drawbeads are one way to regulate and control material flow during the forming process. Not only in research, but also in industrial practice, it could be determined that material is work hardened passing drawbead geometries. It particularly means when material is pre-deformed with tensile and alternating bending loads. This incident also gives the opportunity to utilize it in a reasonable way if examined properly. To investigate these findings, a process oriented and comprehensive analysis of the material behaviour during these forming operations is needed. In this paper, sheet metal strips are linearly drawn through a drawbead and stopped after passing the drawbead. Within this forming operation, the material undergoes non-linear straining before reaching the in-plane position again. Here, the process will be stopped to investigate a permanent strengthening local along the sheet thickness. Therefore, microhardness measurements are realized before and after passing the drawbead. Because of its common use and its wide known material data, a deep drawing steel DC will be used for these studies. Additionally, the strategy is applied to advanced high strength steel.

Permanent tensions in organization.

PubMed

Jansson, Noora

2015-01-01

The purpose of this paper is to investigate the relationship between permanent tensions and organizational change. This study used paradox theory and a case study. The case organization is a public university hospital in Finland involving several stakeholders. The analysis suggests that the relationship between permanent tensions and organizational change is a paradox that is part of organizational reality. As an organization learns to live with its permanent tensions, the renewal paradox settles into equilibrium. When tensions are provoked, the paradox is disturbed until it finds a new balance. This flexible nature of the paradox is the force that keeps the different stakeholders simultaneously empowered to maintain their unique missions and cohesive in order to benefit from the larger synergy. This research suggests that identification and evaluation of each permanent tension within an organization is important when executing organizational change. The fact that certain tensions are permanent and cannot be solved may have an influence on how planned change initiatives are executed. The results show that permanent tensions may be harnessed for the benefit of an organizational change. This research demonstrates originality by offering an alternative view of tensions, a view which emphasizes not only their permanent and plural nature but their importance for enabling the organization to change at its own, non-disruptive pace. The research also proposes a new concept, the "renewal paradox", to enhance understanding of the relationship between permanent tensions and organizational change.

Overjet and overbite analysis during the eruption of the upper permanent incisors.

PubMed

Cuoghi, Osmar A; Sella, Rodrigo C; Mamede, Igo; de Macedo, Fernanda A; Miranda-Zamalloa, Yésselin M; de Mendonça, Marcos R

2009-01-01

ABSTRACT The purpose of this study was to analyze the overjet and overbite behavior during eruption of the upper permanent incisors. Fourth-eight plaster casts of 16 patients from ages 6-13 years were appraised longitudinally. It was found that the overjet remains constant, starting at the eruption of the upper permanent central incisors until eruption of the upper permanent canine teeth, while the overbite increases after eruption of the upper permanent lateral incisors and remains constant with the eruption of the canine teeth.

Design and Development of a Prototype Permanent Magnet for Focusing/Defocusing for Electron-Ion Colliders

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

Wagner, Bob

Electron-ion colliders (EIC) have been identified as an ideal tool to study the next frontier of nuclear physics – the gluon force that holds the building blocks of matter together, and which is a fundamental component of the theory of Quantum Chromodynamics (QCD). Future electron-ion colliders under consideration can be based on the Energy Recovery Linac (ERL) architecture. The beam lines for this architecture could be built of the newly developed Non-Scaling Fixed Field Alternating Gradient (NS FFAG) structure, so that they can transfer multiple energies within the same aperture. This structure allows for the use of compact, economical quadupolemore » permanent magnets. In this SBIR, we propose to design and to manufacture prototype quadrupole permanent magnets of focusing/defocusing combined function for use in this beam line. For our SBIR project, we proposed to design and build the focusing/defocusing quadrupole with a gradient strength of 50 T/m and with a beam gap of 16mm. The proposed permanent magnet material is SmCo because of its higher radiation resistance as compared to NdBFe2. The use of permanent magnets will reduce the overall cost. For Phase I, we took a recent design by Dr. Dejan Trbojevic, and reran Tosca code on the design to optimize the iron yoke with respect to the thickness of SmCo. We then fabricated one prototype focusing/defocusing combined function quadruple and measured field quality dG/Go. Our plan for Phase II is that, based on our Phase I prototype experience, we shall improve the design and fabricate a production quadruple, and design and incorporate coils for skew dipoles and normal quadrupole correctors, etc. In addition, we shall fabricate enough quadrupoles for one cell. The development of quadrupole permanent magnets is of fundamental importance for there application in the future electron-ion colliders. This accelerator structure will also advance the development of muon accelerators and allow for the development of compact, simplified, less expensive proton accelerators which will promote their use in areas such as proton cancer therapy, and for high-power proton drivers for tritium and neutron production, waste transmutation, driving a sub-critical nuclear reactor to produce energy, cargo contain inspection, and radioisotope production. Proton cancer therapy has been identified as a particularly attractive and viable commercial application for the immediate future.« less

50 CFR 32.47 - Nevada.

Code of Federal Regulations, 2010 CFR

2010-10-01

... public from 1 hour before legal sunrise until 1 hour after legal sunset. 4. You may only possess approved... refuge hunting area during the migratory waterfowl hunting season. 3. You may only possess approved... not allow permanent or pit blinds on the refuge. You must remove all blind materials and decoys...

Facilities Requirements for Archives and Special Collections Department.

ERIC Educational Resources Information Center

Brown, Charlotte B.

The program of the Archives and Special Collections Department at Franklin and Marshall College requires the following function areas to be located in the Shadek-Fackenthal Library: (1) Reading Room; (2) Conservation Laboratory; (3) Isolation Room; (4) storage for permanent collection; (5) storage for high security materials; (6) Processing Room;…

75 FR 17638 - National Historical Publications and Records Commission; Proposal To Amend Regulations

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-07

... application deadline, and reflecting the new Office of Management and Budget (OMB) requirement to use Standard... Office of Management and Budget, and is intended to make reporting easier for all Federal grantees. The... policy or to provide procedural details. Historical records means documentary material having permanent...

75 FR 28330 - Proposed Collection; Comment Request for Announcement

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-20

... substantial number of U.S. citizens and lawful permanent residents working in the international community have...,500. Estimated Time per Respondent: 2 hours. Estimated Total Annual Burden Hours: 11,000. An agency... collection of information must be retained as long as their contents may become material in the...

A facile route to steady redox-modulated nitroxide spin-labeled surfaces based on diazonium chemistry.

PubMed

Cougnon, Charles; Boisard, Séverine; Cador, Olivier; Dias, Marylène; Levillain, Eric; Breton, Tony

2013-05-18

A TEMPO derivative was covalently grafted onto carbon and gold surfaces via the diazonium chemistry. The acid-dependent redox properties of the nitroxyl group were exploited to elaborate electro-switchable magnetic surfaces. ESR characterization demonstrated the reversible and permanent magnetic character of the material.

Archaeomagnetic Dating

ERIC Educational Resources Information Center

Linford, Paul

2004-01-01

Some naturally occurring minerals possess a permanent magnetization. Certain processes such as sedimentation or kiln-firing can cause the particles in structures made of such materials to align themselves with the direction of Earth's magnetic field at the time. This direction has varied over the last few thousand years in ways that can be traced…

Physical indicators of hydrologic permanence in forested headwater streams

EPA Science Inventory

Recent court cases have brought headwater streams and their hydrologic permanence into the forefront for regulatory agencies, so rapid field-based indicators of hydrologic permanence in streams are critically needed. Our study objectives were to 1) identify environmental charact...

Dynamic deformations and the M6.7, Northridge, California earthquake

USGS Publications Warehouse

Gomberg, J.

1997-01-01

A method of estimating the complete time-varying dynamic formation field from commonly available three-component single station seismic data has been developed and applied to study the relationship between dynamic deformation and ground failures and structural damage using observations from the 1994 Northridge, California earthquake. Estimates from throughout the epicentral region indicate that the horizontal strains exceed the vertical ones by more than a factor of two. The largest strains (exceeding ???100 ??strain) correlate with regions of greatest ground failure. There is a poor correlation between structural damage and peak strain amplitudes. The smallest strains, ???35 ??strain, are estimated in regions of no damage or ground failure. Estimates in the two regions with most severe and well mapped permanent deformation, Potrero Canyon and the Granada-Mission Hills regions, exhibit the largest strains; peak horizontal strains estimates in these regions equal ???139 and ???229 ??strain respectively. Of note, the dynamic principal strain axes have strikes consistent with the permanent failure features suggesting that, while gravity, sub-surface materials, and hydrologic conditions undoubtedly played fundamental roles in determining where and what types of failures occurred, the dynamic deformation field may have been favorably sized and oriented to initiate failure processes. These results support other studies that conclude that the permanent deformation resulted from ground shaking, rather than from static strains associated with primary or secondary faulting. They also suggest that such an analysis, either using data or theoretical calculations, may enable observations of paleo-ground failure to be used as quantitative constraints on the size and geometry of previous earthquakes. ?? 1997 Elsevier Science Limited.

The Mid-Term Efficacy and Safety of a Permanent Nitinol IVC Filter (TrapEase)

PubMed Central

Liu, Wei Chiang; Choo, Sung Wook; Kim, Dong-Ik; Kim, Young Wook; Kim, Duk-Kyung; Shin, Sung Wook; Park, Kwang Bo; Jeon, Yong Hwan; Choo, In-Wook

2005-01-01

Objective 1) To evaluate the mid-term efficacy and safety of a permanent nitinol inferior vena cava (IVC) filter; 2) to evaluate filter effectiveness, filter stability and caval occlusion. Materials and Methods A prospective evaluation of the TrapEase IVC filter was performed on 42 patients (eight men, 34 women) ranging in age from 22 to 78 years (mean age 66 years). All patients were ill with a high risk of pulmonary embolism (PE). Indications for filter placement were: 1) deep vein thrombosis with recurrent thromboembolism; 2) and/or free-floating thrombus with contraindication to anticoagulation; and 3) complications in achieving adequate anticoagulation. Follow-up evaluations (mean: 15.4 months, range: 2 to 28 months) were performed at 6- and 12-month intervals after the procedure and included clinical histories, chart reviews, plain film, Doppler ultrasounds, and contrasted abdominal CT scans. Results In follow-up evaluations, the data analysis revealed no cases of symptomatic PE. There were no cases of filter migration, insertion site thrombosis, filter fracture, or vessel wall perforation. During the study, there was one case of filter thrombosis; early symptomatic thrombosis that was successfully treated in the hospital. Of the 42 subjects, eight died. These deaths were not related to the filter device or the implantation procedure, but to the underlying disease. Conclusion This study demonstrates that the TrapEase permanent IVC filter is a safe and an effective device with low complication rates and is best used in patients with thromboembolic disease with a high risk of PE. PMID:15968150

Titanium Alloy Strong Back for IXO Mirror Segments

NASA Technical Reports Server (NTRS)

Byron, Glenn P.; Kai-Wang, Chan

2011-01-01

A titanium-alloy mirror-holding fixture called a strong back allows the temporary and permanent bonding of a 50 degree D263 glass x-ray mirror (IXO here stands for International X-ray Observatory). The strong back is used to hold and position a mirror segment so that mounting tabs may be bonded to the mirror with ultra-low distortion of the optical surface. Ti-15%Mo alloy was the material of choice for the strong back and tabs because the coefficient of thermal expansion closely matches that of the D263 glass and the material is relatively easy to machine. This invention has the ability to transfer bonded mounting points from a temporary location on the strong back to a permanent location on the strong back with minimal distortion. Secondly, it converts a single mirror segment into a rigid body with an acceptable amount of distortion of the mirror, and then maneuvers that rigid body into optical alignment such that the mirror segment can be bonded into a housing simulator or mirror module. Key problems are that the mirrors are 0.4-mm thick and have a very low coefficient of thermal expansion (CTE). Because the mirrors are so thin, they are very flexible and are easily distorted. When permanently bonding the mirror, the goal is to achieve a less than 1-micron distortion. Temperature deviations in the lab, which have been measured to be around 1 C, have caused significant distortions in the mirror segment.

Influence of Prostatic Edema on {sup 131}CS Permanent Prostate Seed Implants: A Dosimetric and Radiobiological Study

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

Kehwar, Than S., E-mail: kehwarts@upmc.ed; Jones, Heather A.; Huq, M. Saiful

2011-06-01

Purpose: To study the influence of prostatic edema on postimplant physical and radiobiological parameters using {sup 131}Cs permanent prostate seed implants. Methods and Materials: Thirty-one patients with early prostate cancer who underwent {sup 131}Cs permanent seed implantation were evaluated. Dose-volume histograms were generated for each set of prostate volumes obtained at preimplantation and postimplantion days 0, 14, and 28 to compute quality indices (QIs) and fractional doses at level x (FD{sub x}). A set of equations for QI, FD{sub x}, and biologically effective doses at dose level D{sub x} (BED{sub x}) were defined to account for edema changes with timemore » after implant. Results: There were statistically significant differences found between QIs of pre- and postimplant plans at day 0, except for the overdose index (ODI). QIs correlated with postimplant time, and FD{sub x} was found to increase with increasing postimplant time. With the effect of edema, BED at different dose levels showed less improvement due to the short half-life of {sup 131}Cs, which delivers about 85% of the prescribed dose before the prostate reaches its original volume due to dissipation of edema. Conclusions: Results of the study show that QIs, FD{sub x}, and BEDs at the level of D{sub x} changed from preneedle plans to postimplant plans and have statistically significant differences (p < 0.05), except for the ODI (p = 0.106), which suggests that at the time of {sup 131}C seed implantation, the effect of edema must be accounted for when defining the seed positions, to avoid the possibility of poor dosimetric and radiobiologic results for {sup 131}Cs seed implants.« less

21st Century HVAC System for Future Naval Surface Combatants - Concept Development Report

DTIC Science & Technology

2007-09-01

application of permanent magnet motors to ventilation fans3. The study emphasized reducing the motor size, incorporating variable speed operation to reduce...Incorporation of permanent magnet motors and variable speed is also feasible. Permanent magnet motor technology is ideally suited for variable...family incorporates high speed permanent magnet motors and further fan blade design improvements. The fan diameters will be reduced, substantially, at the

An Evaluation of Electric Motors for Ship Propulsion

DTIC Science & Technology

2003-06-01

AIM). Permanent magnet motors are more power dense than a comparatively sized in- duction motor. The permanent magnet motor has been chosen to...study. They include the axial flux, the ra- dial flux, and the transverse flux permanent magnet motors . Each motor has its unique advantages...to be ideal for ship propulsion, work is ongoing to develop the PMSM for ship propulsion. Permanent magnet motors are expected to have significant

Electric Drive Study

DTIC Science & Technology

1987-03-01

compound promises to reduce weight of future permanent magnet motors by 20 to 30 percent; a similar reduction is expected in size (approximately 20...drive systems. The AC permanent magnet (brushless DC motor) is rapidly evolving and will replace most electrically excited machines. Permanent magnet motors using

Larval salamanders and channel geomorphology are indicators of hydrologic permanence in forested headwater streams

EPA Science Inventory

Regulatory agencies need rapid indicators of hydrologic permanence for jurisdictional determinations of headwater streams. Our study objective was to assess the utility of larval salamander presence and assemblage structure and habitat variables for determining stream permanence ...

Experimental and Analytical Seismic Studies of a Four-Span Bridge System with Innovative Materials

NASA Astrophysics Data System (ADS)

Cruz Noguez, Carlos Alonso

As part of a multi-university project utilizing the NSF Network for Earthquake Engineering Simulation (NEES), a quarter-scale model of a four-span bridge incorporating plastic hinges with different advanced materials was tested to failure on the three shake table system at the University of Nevada, Reno (UNR). The bridge was the second test model in a series of three 4-span bridges, with the first model being a conventional reinforced-concrete (RC) structure. The purpose of incorporating advanced materials was to improve the seismic performance of the bridge with respect to two damage indicators: (1) column damage and (2) permanent deformations. The goals of the study presented in this document were to (1) evaluate the seismic performance of a 4-span bridge system incorporating SMA/ECC and built-in rubber pad plastic hinges as well as post-tensioned piers, (2) quantify the relative merit of these advanced materials and details compared to each other and to conventional reinforced concrete plastic hinges, (3) determine the influence of abutment-superstructure interaction on the response, (4) examine the ability of available elaborate analytical modeling techniques to model the performance of advanced materials and details, and (5) conduct an extensive parametric study of different variations of the bridge model to study several important issues in bridge earthquake engineering. The bridge model included six columns, each pair of which utilized a different advanced detail at bottom plastic hinges: shape memory alloys (SMA), special engineered cementitious composites (ECC), elastomeric pads embedded into columns, and post-tensioning tendons. The design of the columns, location of the bents, and selection of the loading protocol were based on pre-test analyses conducted using computer program OpenSees. The bridge model was subjected to two-horizontal components of simulated earthquake records of the 1994 Northridge earthquake. Over 340 channels of data were collected. The test results showed the effectiveness of the advanced materials in reducing damage and permanent displacements. The damage was minimal in plastic hinges with SMA/ECC and those with built-in elastomeric pads. Conventional RC plastic hinges were severely damaged due to spalling of concrete and rupture of the longitudinal and transverse reinforcement. Extensive post-test analytical studies were conducted and it was determined that a computational model of the bridge that included bridge-abutment interaction using OpenSees was able to provide satisfactory estimations of key structural parameters such as superstructure displacements and base shears. The analytical model was also used to conduct parametric studies on single-column and bridge-system response under near-fault ground motions. The effects of vertical excitations and transverse shear-keys at the bridge abutments on the superstructure displacement and column drifts were also explored.

Figure of Merit Characteristics Compared to Engineering Parameters

NASA Technical Reports Server (NTRS)

Rickman, Doug L.; Schrader, Christian M.

2008-01-01

Current NASA lunar architecture calls for permanent human habitation of the moon by the year 2020. Due to the expense of delivering materials into orbit, technologies are being developed to use lunar regolith for building and as a material resource for fabrication, oxygen production, and other needs. Additionally, constant exposure to the finest size fraction of lunar regolith may present hazards to human health. Towards developing these technologies and mitigating hazards, lunar regolith simulants are becoming an increasingly important part of the development paradigm.

Glass strengthening and patterning methods

DOEpatents

Harper, David C; Wereszczak, Andrew A; Duty, Chad E

2015-01-27

High intensity plasma-arc heat sources, such as a plasma-arc lamp, are used to irradiate glass, glass ceramics and/or ceramic materials to strengthen the glass. The same high intensity plasma-arc heat source may also be used to form a permanent pattern on the glass surface--the pattern being raised above the glass surface and integral with the glass (formed of the same material) by use of, for example, a screen-printed ink composition having been irradiated by the heat source.

Supercritical processing as a route to high internal surface areas and permanent microporosity in metal-organic framework materials.

PubMed

Nelson, Andrew P; Farha, Omar K; Mulfort, Karen L; Hupp, Joseph T

2009-01-21

Careful processing of four representative metal-organic framework (MOF) materials with liquid and supercritical carbon dioxide (ScD) leads to substantial, or in some cases spectacular (up to 1200%), increases in gas-accessible surface area. Maximization of surface area is key to the optimization of MOFs for many potential applications. Preliminary evidence points to inhibition of mesopore collapse, and therefore micropore accessibility, as the basis for the extraordinarily efficacious outcome of ScD-based activation.

Proliferation risks from nuclear power infrastructure

NASA Astrophysics Data System (ADS)

Squassoni, Sharon

2017-11-01

Certain elements of nuclear energy infrastructure are inherently dual-use, which makes the promotion of nuclear energy fraught with uncertainty. Are current restraints on the materials, equipment, and technology that can be used either to produce fuel for nuclear electricity generation or material for nuclear explosive devices adequate? Technology controls, supply side restrictions, and fuel market assurances have been used to dissuade countries from developing sensitive technologies but the lack of legal restrictions is a continued barrier to permanent reduction of nuclear proliferation risks.

Eruption of first permanent incisors and live weight gain in grazing yearling Angora goats.

PubMed

McGregor, B A; Butler, K L

2013-05-01

To investigate the effects of the timing and duration of eruption of the first permanent incisors, live weight, sex and other factors on contemporaneous live weight gain in Angora goats. Goats were previously part of a pen study on the effects of energy intake of Angora does during pregnancy and lactation on kid development. The design was 3 levels of nutrition in mid-pregnancy by 2 levels of postnatal nutrition in 17 randomised blocks. Artificial insemination, ultrasound examination and feeding does in pens enabled accurate conduct of the study. After weaning, goats were grazed in sex groups. Live weight change between 14 and 20 months of age was related to deciduous first incisor loss and permanent first incisor development and other attributes assessed before the study. Live weight change was related to the elapsed time for first permanent incisors to commence eruption and to the length of time for first permanent incisors to erupt. This response was affected by sex. Over summer and autumn, entire males with short eruption intervals gained 2-3 kg more than entire males with long eruption intervals. Females that reached first permanent incisor eruption by mid-summer had a live weight gain of 3 kg more than those that reached the same development 3 months later. Live weight change in yearling Angora goats was associated with the process of first permanent incisor eruption. In females, live weight gain was greater when first permanent incisor eruption was earlier. In males, live weight gain was greater when first permanent incisor eruption was faster. © 2013 The Authors. Australian Veterinary Journal © 2013 Australian Veterinary Association.

Do permanent night workers show circadian adjustment? A review based on the endogenous melatonin rhythm.

PubMed

Folkard, Simon

2008-04-01

"Permanent" or "fixed" night shifts have been argued to offer a potential benefit over rotating shift systems in that they may serve to maximize circadian adjustment and hence minimize the various health and safety problems associated with night work. For this reason, some authors have argued in favor of permanent shift systems, but their arguments assume at least a substantial, if not complete, adjustment of the circadian clock. They have emphasized the finding that the day sleeps taken between successive night shifts by permanent night workers are rather longer than those of either slowly or rapidly rotating shift workers, but this could simply reflect increased pressure for sleep. The present paper reviews the literature on the adjustment to permanent night work of the circadian rhythm in the secretion of melatonin, which is generally considered to be the best known indicator of the state of the endogenous circadian body clock. Studies of workers in "abnormal" environments, such as oil rigs and remote mining operations, were excluded, as the nature of these unique settings might serve to assist adjustment. The results of the six studies included indicate that only a very small minority (<3%) of permanent night workers evidence "complete"adjustment of their endogenous melatonin rhythm to night work, less than one in four permanent night workers evidence sufficiently "substantial" adjustment to derive any benefit from it, there is no difference between studies conducted in normal or dim lighting, and there is no evidence of gender difference in the adjustment to permanent night work. It is concluded that in normal environments, permanent night-shift systems are unlikely to result in sufficient circadian adjustment in most individuals to benefit health and safety.

Replacement and Original Magnet Engineering Options (ROMEOs): A European Seventh Framework Project to Develop Advanced Permanent Magnets Without, or with Reduced Use of, Critical Raw Materials

NASA Astrophysics Data System (ADS)

Mcguiness, P.; Akdogan, O.; Asali, A.; Bance, S.; Bittner, F.; Coey, J. M. D.; Dempsey, N. M.; Fidler, J.; Givord, D.; Gutfleisch, O.; Katter, M.; Le Roy, D.; Sanvito, S.; Schrefl, T.; Schultz, L.; Schwöbl, C.; Soderžnik, M.; Šturm, S.; Tozman, P.; Üstüner, K.; Venkatesan, M.; Woodcock, T. G.; Žagar, K.; Kobe, S.

2015-06-01

The rare-earth crisis, which peaked in the summer of 2011 with the prices of both light and heavy rare earths soaring to unprecedented levels, brought about the widespread realization that the long-term availability and price stability of rare earths could not be guaranteed. This triggered a rapid response from manufacturers involved in rare earths, as well as governments and national and international funding agencies. In the case of rare-earth-containing permanent magnets, three possibilities were given quick and serious consideration: (I) increased recycling of devices containing rare earths; (II) the search for new, mineable, rare-earth resources beyond those in China; and (III) the development of high-energy-product permanent magnets with little or no rare-earth content used in their manufacture. The Replacement and Original Magnet Engineering Options (ROMEO) project addresses the latter challenge using a two-pronged approach. With its basis on work packages that include materials modeling and advanced characterization, the ROMEO project is an attempt to develop a new class of novel permanent magnets that are free of rare earths. Furthermore, the project aims to minimize rare-earth content, particularly heavy-rare-earth (HRE) content, as much as possible in Nd-Fe-B-type magnets. Success has been achieved on both fronts. In terms of new, rare-earth-free magnets, a Heusler alloy database of 236,945 compounds has been narrowed down to approximately 20 new compounds. Of these compounds, Co2MnTi is expected to be a ferromagnet with a high Curie temperature and a high magnetic moment. Regarding the reduction in the amount of rare earths, and more specifically HREs, major progress is seen in electrophoretic deposition as a method for accurately positioning the HRE on the surface prior to its diffusion into the microstructure. This locally increases the coercivity of the rather small Nd-Fe-B-type magnet, thereby substantially reducing the dependence on the HREs Dy and Tb, two of the most critical raw materials identified by the European Commission. Overall, the ROMEO project has demonstrated that rapid progress can be achieved when experts in a specific area are brought together to focus on a particular challenge. With more than half a year of the ROMEO project remaining, further progress and additional breakthroughs can be expected.

Direct chill casting of aluminium alloys under electromagnetic interaction by permanent magnet assembly

NASA Astrophysics Data System (ADS)

Bojarevičs, Andris; Kaldre, Imants; Milgrāvis, Mikus; Beinerts, Toms

2018-05-01

Direct chill casting is one of the methods used in industry to obtain good microstructure and properties of aluminium alloys. Nevertheless, for some alloys grain structure is not optimal. In this study, we offer the use of electromagnetic interaction to modify melt convection near the solidification interface. Solidification under various electromagnetic interactions has been widely studied, but usually at low solidification velocity and high thermal gradient. This type of interaction may succeed fragmentation of dendrite arms and transport of solidification nuclei thus leading to improved material structure and properties. Realization of experimental small-scale crystallizer and electromagnetic system has been described in this article.

Beagle 2 the Moon: An Experimental Package to Measure Polar Ice and Volatiles in Permanently Shadowed Areas or Beneath the Lunar Surface

NASA Technical Reports Server (NTRS)

Gibson, E. K.; McKay, D. S.; Pillinger, C. T.; Wright, I. P.; Sims, M. R.; Richter, L.

2008-01-01

NASA has announced the selection of several Lunar Science Sortie Concept Studies for potential scientific payloads with future Lunar Missions. The Beagle 2 scientific package was one of those chosen for study. Near the beginning of the next decade will see the launch of scientific payloads to the lunar surface to begin laying the foundations for the return to the moon in the Vision for Space Exploration. Shortly thereafter, astronauts will return to the lunar surface with the ability to place scientific packages on the surface that will provide information about lunar resources and compositions of materials in permanently shadowed regions of the moon (1). One of the important questions which must be answered early in the program is whether there are lunar resources which would facilitate "living off the land" and not require the transport of resources and consumables from Earth (2). The Beagle science package developed to seek the signatures of life on Mars is the ideal payload (3) to use on the lunar surface for determining the nature of hydrogen, water and lunar volatiles found in the polar regions which could support the Vision for Space Exploration.

Intense beams from gases generated by a permanent magnet ECR ion source at PKU.

PubMed

Ren, H T; Peng, S X; Lu, P N; Yan, S; Zhou, Q F; Zhao, J; Yuan, Z X; Guo, Z Y; Chen, J E

2012-02-01

An electron cyclotron resonance (ECR) ion source is designed for the production of high-current ion beams of various gaseous elements. At the Peking University (PKU), the primary study is focused on developing suitable permanent magnet ECR ion sources (PMECRs) for separated function radio frequency quadrupole (SFRFQ) accelerator and for Peking University Neutron Imaging Facility. Recently, other kinds of high-intensity ion beams are required for new acceleration structure demonstration, simulation of fusion reactor material irradiation, aviation bearing modification, and other applications. So we expanded the ion beam category from O(+), H(+), and D(+) to N(+), Ar(+), and He(+). Up to now, about 120 mA of H(+), 83 mA of D(+), 50 mA of O(+), 63 mA of N(+), 70 mA of Ar(+), and 65 mA of He(+) extracted at 50 kV through a φ 6 mm aperture were produced by the PMECRs at PKU. Their rms emittances are less than 0.2 π mm mrad. Tungsten samples were irradiated by H(+) or He(+) beam extracted from this ion source and H∕He holes and bubbles have been observed on the samples. A method to produce a high intensity H∕He mixed beam to study synergistic effect is developed for nuclear material irradiation. To design a He(+) beam injector for coupled radio frequency quadruple and SFRFQ cavity, He(+) beam transmission experiments were carried out on PKU low energy beam transport test bench and the transmission was less than 50%. It indicated that some electrode modifications must be done to decrease the divergence of He(+) beam.

Fascian.

PubMed

Burres, Steve

2004-05-01

Fascian is preserved particulate fascia derived from the gastrocnemious fascia that extends from the Achilles tendon. Over 50,000 syringes of material have been sold to physicians over the past six years with an impeccable safety record. The material has been used for wrinkles, scars, fat atrophy, diffuse depressions, paralyzed lips and tongues, nasolabial folds, cellulite, and other problems. Solid fascia grafts are routinely replaced with native collagen and a similar effect may be achieved with Fascian, especially after repeat injections. The FDA classifies the material as a tissue product, so injections may be made anywhere in the human body at the physician's discretion. Injections may last from a few months to permanently, depending on the volume of material, location, particle size, skin layer, and technique.

Design and application of permanent magnet flux sources for mechanical testing of magnetoactive elastomers at variable field directions.

PubMed

Hiptmair, F; Major, Z; Haßlacher, R; Hild, S

2015-08-01

Magnetoactive elastomers (MAEs) are a class of smart materials whose mechanical properties can be rapidly and reversibly changed by an external magnetic field. Due to this tunability, they are useable for actuators or in active vibration control applications. An extensive magnetomechanical characterization is necessary for MAE material development and requires experiments under cyclic loading in uniform but variable magnetic fields. MAE testing apparatus typically rely on fields of adjustable strength, but fixed (transverse) direction, often provided by electromagnets. In this work, two permanent magnet flux sources were developed as an add-on for a modular test stand, to allow for mechanical testing in uniform fields of variable direction. MAE specimens, based on a silicone matrix with isotropic and anisotropic carbonyl iron particle distributions, were subjected to dynamic mechanical analysis under different field and loading configurations. The magneto-induced increase of stiffness and energy dissipation was determined by the change of the hysteresis loop area and dynamic modulus values. A distinct influence of the composite microstructure and the loading state was observed. Due to the very soft and flexible matrix used for preparing the MAE samples, the material stiffness and damping behavior could be varied over a wide range via the applied field direction and intensity.

Modeling the Stability of Volatile Deposits in Lunar Cold Traps

NASA Technical Reports Server (NTRS)

Crider, D. H.; Vondrak, R. R.

2002-01-01

There are several mechanisms acting at the cold traps that can alter the inventory of volatiles there. Primarily, the lunar surface is bombarded by meteoroids which impact, melt, process, and redistribute the regolith. Further, solar wind and magnetospheric ion fluxes are allowed limited access onto the regions in permanent shadow. Also, although cold traps are in the permanent shadow of the Sun, there is a small flux of radiation incident on the regions from interstellar sources. We investigate the effects of these space weathering processes on a deposit of volatiles in a lunar cold trap through simulations. We simulate the development of a column of material near the surface of the Moon resulting from space weathering. This simulation treats a column of material at a lunar cold trap and focuses on the hydrogen content of the column. We model space weathering processes on several time and spatial scales to simulate the constant rain of micrometeoroids as well as sporadic larger impactors occurring near the cold traps to determine the retention efficiency of the cold traps. We perform the Monte Carlo simulation over many columns of material to determine the expectation value for hydrogen content of the top few meters of soil for comparison with Lunar Prospector neutron data.

The Effectiveness of Teacher Work between Permanent and Non-Permanent Teachers on the Implementation of School-Based Management in Muhammadiyah Metro Elementary School

ERIC Educational Resources Information Center

Juhri, A. M.; Tri, Y. H.; Agus, S.

2017-01-01

The study aims to obtain empirical evidence of the differences in the effectiveness of work on several aspects, including preparing and planning learning activities, the implementation of public administration, responsibility, and task. The study was carried out between the two groups, which were permanent and nonpermanent teachers in Muhamamdiyah…

The Concept of Permanent Education and Its Application in Denmark. Studies on Permanent Education, No. 2.

ERIC Educational Resources Information Center

Rasmussen, Werner

A report is made to the Secretariat of the Council of Europe of a case study on the introduction of the concept of permanent education in Denmark. The supplies of education, which have been limited to clients in childhhod, adolescence, and yound adulthood, should now be distributed over a lifetime. Economic growth was formerly explained by input…

Low elastic modulus Ti-Ta alloys for load-bearing permanent implants: enhancing the biodegradation resistance by electrochemical surface engineering.

PubMed

Kesteven, Jazmin; Kannan, M Bobby; Walter, Rhys; Khakbaz, Hadis; Choe, Han-Choel

2015-01-01

In this study, the in vitro degradation behaviour of titanium-tantalum (Ti-Ta) alloys (10-30 wt.% Ta) was investigated and compared with conventional implant materials, i.e., commercially pure titanium (Cp-Ti) and titanium-aluminium-vanadium (Ti6Al4V) alloy. Among the three Ti-Ta alloys studied, the Ti20Ta (6.3×10(-4) mm/y) exhibited the lowest degradation rate, followed by Ti30Ta (1.2×10(-3) mm/y) and Ti10Ta (1.4×10(-3) mm/y). All the Ti-Ta alloys exhibited lower degradation rate than that of Cp-Ti (1.8×10(-3) mm/y), which suggests that Ta addition to Ti is beneficial. As compared to Ti6Al4V alloy (8.1×10(-4) mm/y), the degradation rate of Ti20Ta alloy was lower by ~22%. However, the Ti30Ta alloy, which has closer elastic modulus to that of natural bone, showed ~48% higher degradation rate than that of Ti6Al4V alloy. Hence, to improve the degradation performance of Ti30Ta alloy, an intermediate thin porous layer was formed electrochemically on the alloy followed by calcium phosphate (CaP) electrodeposition. The coated Ti30Ta alloy (3.8×10(-3) mm/y) showed ~53% lower degradation rate than that of Ti6Al4V alloy. Thus, the study suggests that CaP coated Ti30Ta alloy can be a viable material for load-bearing permanent implants. Copyright © 2014 Elsevier B.V. All rights reserved.

The Use of Glass-fibers Ribbon and Composite for Prosthetic Restoration of Missing Primary Teeth-Laboratory and Clinical Research

PubMed Central

Zilberman, Uri; Lasilla, Lippo

2014-01-01

Very few modalities can be used for restoring missing primary anterior teeth, although the impact of missing anterior teeth during early childhood can be harmful. In the permanent dentition the use of glass-fibers ribbon and composite materials are frequently used for restoring missing teeth with no or minimal preparation. The purpose of this study was to examine the possibility to use the glass-fibers ribbon (ever-Stick from GC Corporation, Japan) together with esthetic composite materials (G-aenial A1 from GC Corporation, Japan) for restoring anterior primary teeth and to determine the best methodology and bonding system to be used. The effect of etching time was analyzed using 20-80 sec on primary buccal enamel with SEM and the results showed that at least 60 second is necessary in order to remove the prismless layer and to affect the prismatic layer similar (as observed by SEM) to the 20 sec etching time on permanent enamel. Three bonding systems (SE Bond by Kurary, Japan, Scotchbond Universal by 3M/ESPE, Germany and G-aenial bond by GC Company, Japan) were compared for bonding the glass-fibers ribbon to the primary enamel and microtensile strength analyses were performed. Mean tensile strength ranged from 10.9 to 13 MPa with no statistically significant differences between all three systems. Based on the laboratory results it can be concluded that the glass-fibers ribbon together with the composite material can be used clinically to restore missing primary teeth for esthetic and functional reasons. Two clinical cases are presented that show favorable results. PMID:25553140

A bioactive dental luting cement--its retentive properties and 3-year clinical findings.

PubMed

Jefferies, Steven R; Pameijer, Cornelis H; Appleby, David C; Boston, Daniel; Lööf, Jesper

2013-02-01

A clinical validation study was conducted to determine the performance of a new bioactive dental cement (Ceramir C&B, Doxa Dental AB) for permanent cementation. The cement is a new formulation class, which is a hybrid material comprised of calcium aluminate and glass-ionomer components. A total of 38 crowns and bridges were cemented in 17 patients; 31 of the abutment teeth were vital and seven were non-vital. Six restorations were bridges with a total of 14 abutment teeth (12 vital/ two non-vital). One fixed splint comprising two abutment teeth was also included. Preparation parameters were recorded, as well as cement characteristics such as working time, setting time, seating characteristics, and ease of cement removal. Baseline data were recorded for the handling of the cement, gingival inflammation, and pre-cementation sensitivity. Post-cementation parameters included post-cementation sensitivity, gingival tissue reaction, marginal integrity, and discoloration. All patients were seen for recall examinations at 30 days and 6 months. Fifteen of 17 subjects and 13 of 17 patients were also available for subsequent comprehensive 1- and 2-year recall examination, and 13 patients were available for a 3-year recall examination. Restorations available for the 3-year recall examination included 14 single-unit full-coverage crown restorations, four three-unit bridges comprising eight abutments, and one two-unit splint. Three-year recall data yielded no loss of retention, no secondary caries, no marginal discolorations, and no subjective sensitivity. All restorations rated excellent for marginal integrity. Average visual analogue scale (VAS) score for tooth sensitivity decreased from 7.63 mm at baseline to 0.44 mm at 6-month recall, 0.20 mm at 1-year recall, and 0.00 mm at 2- and 3-year recall. Average gingival index (GI) score for gingival inflammation decreased from 0.56 at baseline to 0.11 at 6-month recall, 0.16 at 1-year recall, 0.21 at 2-year recall, and 0.07 at 3-year recall. After periodic recalls up to 3 years, Ceramir C&B thus far has performed quite favorably as a luting agent for permanent cementation of permanent restorations. In-vitro crown-coping retention studies were also conducted using this cement and various control cementation materials. Mean laboratory retentive forces measured for Ceramir C&B were comparable to other currently available luting agents for both metal and all-ceramic indirect restorative materials.

A mobile ferromagnetic shape detection sensor using a Hall sensor array and magnetic imaging.

PubMed

Misron, Norhisam; Shin, Ng Wei; Shafie, Suhaidi; Marhaban, Mohd Hamiruce; Mailah, Nashiren Farzilah

2011-01-01

This paper presents a mobile Hall sensor array system for the shape detection of ferromagnetic materials that are embedded in walls or floors. The operation of the mobile Hall sensor array system is based on the principle of magnetic flux leakage to describe the shape of the ferromagnetic material. Two permanent magnets are used to generate the magnetic flux flow. The distribution of magnetic flux is perturbed as the ferromagnetic material is brought near the permanent magnets and the changes in magnetic flux distribution are detected by the 1-D array of the Hall sensor array setup. The process for magnetic imaging of the magnetic flux distribution is done by a signal processing unit before it displays the real time images using a netbook. A signal processing application software is developed for the 1-D Hall sensor array signal acquisition and processing to construct a 2-D array matrix. The processed 1-D Hall sensor array signals are later used to construct the magnetic image of ferromagnetic material based on the voltage signal and the magnetic flux distribution. The experimental results illustrate how the shape of specimens such as square, round and triangle shapes is determined through magnetic images based on the voltage signal and magnetic flux distribution of the specimen. In addition, the magnetic images of actual ferromagnetic objects are also illustrated to prove the functionality of mobile Hall sensor array system for actual shape detection. The results prove that the mobile Hall sensor array system is able to perform magnetic imaging in identifying various ferromagnetic materials.

A Mobile Ferromagnetic Shape Detection Sensor Using a Hall Sensor Array and Magnetic Imaging

PubMed Central

Misron, Norhisam; Shin, Ng Wei; Shafie, Suhaidi; Marhaban, Mohd Hamiruce; Mailah, Nashiren Farzilah

2011-01-01

This paper presents a Mobile Hall Sensor Array system for the shape detection of ferromagnetic materials that are embedded in walls or floors. The operation of the Mobile Hall Sensor Array system is based on the principle of magnetic flux leakage to describe the shape of the ferromagnetic material. Two permanent magnets are used to generate the magnetic flux flow. The distribution of magnetic flux is perturbed as the ferromagnetic material is brought near the permanent magnets and the changes in magnetic flux distribution are detected by the 1-D array of the Hall sensor array setup. The process for magnetic imaging of the magnetic flux distribution is done by a signal processing unit before it displays the real time images using a netbook. A signal processing application software is developed for the 1-D Hall sensor array signal acquisition and processing to construct a 2-D array matrix. The processed 1-D Hall sensor array signals are later used to construct the magnetic image of ferromagnetic material based on the voltage signal and the magnetic flux distribution. The experimental results illustrate how the shape of specimens such as square, round and triangle shapes is determined through magnetic images based on the voltage signal and magnetic flux distribution of the specimen. In addition, the magnetic images of actual ferromagnetic objects are also illustrated to prove the functionality of Mobile Hall Sensor Array system for actual shape detection. The results prove that the Mobile Hall Sensor Array system is able to perform magnetic imaging in identifying various ferromagnetic materials. PMID:22346653

Theoretical study of local magnetocrystalline anisotropy of ɛ-Fe2O3

NASA Astrophysics Data System (ADS)

Hirai, Daisuke; Tsuneyuki, Shinji; Gohda, Yoshihiro

2015-03-01

Magnetocrystalline anisotropy (MCA) is positively correlated with corercivity that is one of important magnetic figures of merit for applications such as high-density magnetic recording media, high-frequency electromagnetic wave absorbers, and permanent magnets. In general, MCA is given for an entire phase of a material. In light of materials engineering, however, MCA information at respective atoms in crystals is useful to identify weak parts for possible nucleation cores of magnetic reversal and design the local MCA. Considering these facts, we examined the local MCA of hard magnetic materials on the basis of density functional theory and the second perturbation theory on spin-orbit interaction. We studied the magnetic properties of ɛ-Fe2O3, which shows the largest coercivity among all the metal oxides. Particularly, we tried to elucidate the effect of an oxygen vacancy on the magnetic properties. As a result, we clarified that the vacancy enhances both the magnetic moment and MAE. We acknowledge partial financial support from the Elemental Strategy Initiative Center for Magnetic Materials (ESICMM) under outsourcing project of MEXT. The computation was partly carried out on the K-computer (Grant No. hp120086).

Incidence of permanent hypocalcaemia after total thyroidectomy with or without central neck dissection for thyroid carcinoma: a nationwide claim study.

PubMed

Seo, Gi Hyeon; Chai, Young Jun; Choi, Hyung Jin; Lee, Kyu Eun

2016-09-01

Permanent hypocalcaemia is the most common and serious complication after total thyroidectomy (TT). This study examined the impact of central neck dissection (CND) and institutional volume on rates of permanent hypocalcaemia by analysing data held in the nationwide claim database of South Korea. Data from patients who underwent TT due to thyroid carcinoma from 2007-2013 were obtained from the Health Insurance Review and Assessment Service database. Of these, patients prescribed more than 1000 mg of elemental calcium for more than 288 days during the first 360 days postsurgery were defined as having permanent hypocalcaemia. In total, 192 333 patients (32 988 male and 159 345 female) were eligible for analysis. Of these, 52 707 (27·4%) underwent TT alone and 139 626 (72·6%) underwent TT plus CND. The incidence of permanent hypocalcaemia was greater in the TT plus CND group than in the TT alone group (5·4% vs 4·6%, P < 0·001). The age- and sex-adjusted risk for permanent hypocalcaemia in the TT plus CND group was 1·20 (P < 0·001). CND did not raise the rates of permanent hypocalcaemia in institutes with a low volume of annual cases (<200), whereas permanent hypocalcaemia was more common in the TT plus CND group than in the TT alone group (3·5% vs 2·9%, P = 0·002) in institutes with a large volume of annual cases (≥800). TT plus CND was associated with a greater risk of permanent hypocalcaemia than TT alone. Surgeons should consider the risk of permanent hypocalcaemia when deciding whether to perform CND. © 2016 John Wiley & Sons Ltd.

Resource requirements of inclusive urban development in India: insights from ten cities

NASA Astrophysics Data System (ADS)

Singh Nagpure, Ajay; Reiner, Mark; Ramaswami, Anu

2018-02-01

This paper develops a methodology to assess the resource requirements of inclusive urban development in India and compares those requirements to current community-wide material and energy flows. Methods include: (a) identifying minimum service level benchmarks for the provision of infrastructure services including housing, electricity and clean cooking fuels; (b) assessing the percentage of homes that lack access to infrastructure or that consume infrastructure services below the identified benchmarks; (c) quantifying the material requirements to provide basic infrastructure services using India-specific design data; and (d) computing material and energy requirements for inclusive development and comparing it with current community-wide material and energy flows. Applying the method to ten Indian cities, we find that: 1%-6% of households do not have electricity, 14%-71% use electricity below the benchmark of 25 kWh capita-month-1 4%-16% lack structurally sound housing; 50%-75% live in floor area less than the benchmark of 8.75 m2 floor area/capita; 10%-65% lack clean cooking fuel; and 6%-60% lack connection to a sewerage system. Across the ten cities examined, to provide basic electricity (25 kWh capita-month-1) to all will require an addition of only 1%-10% in current community-wide electricity use. To provide basic clean LPG fuel (1.2 kg capita-month-1) to all requires an increase of 5%-40% in current community-wide LPG use. Providing permanent shelter (implemented over a ten year period) to populations living in non-permanent housing in Delhi and Chandigarh would require a 6%-14% increase over current annual community-wide cement use. Conversely, to provide permanent housing to all people living in structurally unsound housing and those living in overcrowded housing (<5 m cap-2) would require 32%-115% of current community-wide cement flows. Except for the last scenario, these results suggest that social policies that seek to provide basic infrastructure provisioning for all residents would not dramatically increasing current community-wide resource flows.

Core losses of a permanent magnet synchronous motor with an amorphous stator core under inverter and sinusoidal excitations

NASA Astrophysics Data System (ADS)

Yao, Atsushi; Sugimoto, Takaya; Odawara, Shunya; Fujisaki, Keisuke

2018-05-01

We report core loss properties of permanent magnet synchronous motors (PMSM) with amorphous magnetic materials (AMM) core under inverter and sinusoidal excitations. To discuss the core loss properties of AMM core, a comparison with non-oriented (NO) core is also performed. In addition, based on both experiments and numerical simulations, we estimate higher (time and space) harmonic components of the core losses under inverter and sinusoidal excitations. The core losses of PMSM are reduced by about 59% using AMM stator core instead of NO core under sinusoidal excitation. We show that the average decrease obtained by using AMM instead of NO in the stator core is about 94% in time harmonic components.

Core losses of an inverter-fed permanent magnet synchronous motor with an amorphous stator core under no-load

NASA Astrophysics Data System (ADS)

Denis, Nicolas; Kato, Yoshiyuki; Ieki, Masaharu; Fujisaki, Keisuke

2016-05-01

In this paper, an interior permanent magnet synchronous motor (IPMSM) with a stator core made of amorphous magnetic material (AMM) is presented. The IPMSM is driven by a voltage source three-phase inverter with classical pulse width modulation (PWM) control. The core losses under no-load condition are measured by experiment and compared to an equivalent IPMSM with a stator core made of NO steel. Under these conditions, the core losses are influenced by the stator, rotor and magnet shapes but also by the PWM carrier signal that implies a high frequency harmonic in the magnetic flux density. It is demonstrated that the AMM can reduce the core losses by about 56 %.

Cluster-Expansion Model for Complex Quinary Alloys: Application to Alnico Permanent Magnets

NASA Astrophysics Data System (ADS)

Nguyen, Manh Cuong; Zhou, Lin; Tang, Wei; Kramer, Matthew J.; Anderson, Iver E.; Wang, Cai-Zhuang; Ho, Kai-Ming

2017-11-01

An accurate and transferable cluster-expansion model for complex quinary alloys is developed. Lattice Monte Carlo simulation enabled by this cluster-expansion model is used to investigate temperature-dependent atomic structure of alnico alloys, which are considered as promising high-performance non-rare-earth permanent-magnet materials for high-temperature applications. The results of the Monte Carlo simulations are consistent with available experimental data and provide useful insights into phase decomposition, selection, and chemical ordering in alnico. The simulations also reveal a previously unrecognized D 03 alloy phase. This phase is very rich in Ni and exhibits very weak magnetization. Manipulating the size and location of this phase provides a possible route to improve the magnetic properties of alnico, especially coercivity.

Determinants of long acting and permanent contraceptive methods utilization among married women of reproductive age groups in western Ethiopia: a cross-sectional study.

PubMed

Melka, Alemu Sufa; Tekelab, Tesfalidet; Wirtu, Desalegn

2015-01-01

In Ethiopia information on the level of utilization of the long term and permanent contraceptive methods and associated factorsis lacking. The aim of this study was to understand the determinant factors of long acting and permanent contraceptive methods use among married women of reproductive age in Western Ethiopia. A community based cross-sectional study design was employed. Multi stage sampling was used to select 1003 study participants. Data was collected from April 10 to April 25,2014 using a pre- tested structured questionnaire. The data were entered using Epi-info version 3.5.1 and exported to SPSS version 20 for analysis. Multivariate logistic regression analysis was done to identify predictors of long acting and permanent contraceptive methods at 95% CL. Use of long acting and permanent contraceptive methods in this study was found to be 20%. Survey results showed a significant positive association between utilization of long acting and permanent contraceptive methods and women's education (AOR=1.72, 95%CI=1.02-3.05), women's occupation (AOR=2.01, 95% CI=1.11-3.58), number of live children (AOR=2.42, 95% CI: 1.46-4.02), joint fertility related decision (AOR=6.11, 95% CI: 2.29-16.30), having radio/TV (AOR=2.31, 95% CI: 1.40-3.80), and discussion with health care provider about long acting and permanent contraceptive methods (AOR=13.72, 95% CI: 8.37-22.47). Efforts need to be aimed at women empowerment, health education, and encouraging open discussion of family planning by couples.

12 CFR 403.7 - Mandatory review for declassification.

Code of Federal Regulations, 2011 CFR

2011-01-01

... of a request by a United States citizen or permanent resident alien, a Federal agency, or a State or... material on grounds other than classification. (i) The Bank shall refuse to confirm or deny the existence or non-existence of requested information whenever the fact of its existence or non-existence is...

12 CFR 403.7 - Mandatory review for declassification.

Code of Federal Regulations, 2012 CFR

2012-01-01

... of a request by a United States citizen or permanent resident alien, a Federal agency, or a State or... material on grounds other than classification. (i) The Bank shall refuse to confirm or deny the existence or non-existence of requested information whenever the fact of its existence or non-existence is...

12 CFR 403.7 - Mandatory review for declassification.

Code of Federal Regulations, 2014 CFR

2014-01-01

... of a request by a United States citizen or permanent resident alien, a Federal agency, or a State or... material on grounds other than classification. (i) The Bank shall refuse to confirm or deny the existence or non-existence of requested information whenever the fact of its existence or non-existence is...

12 CFR 403.7 - Mandatory review for declassification.

Code of Federal Regulations, 2013 CFR

2013-01-01

... of a request by a United States citizen or permanent resident alien, a Federal agency, or a State or... material on grounds other than classification. (i) The Bank shall refuse to confirm or deny the existence or non-existence of requested information whenever the fact of its existence or non-existence is...

29 CFR 1919.17 - Exemptions from heat treatment.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 7 2010-07-01 2010-07-01 false Exemptions from heat treatment. 1919.17 Section 1919.17... from heat treatment. Gear made of steel, or gear which contains (as in ball bearings swivels), or is permanently attached to (as with blocks) equipment made of materials which cannot be subjected to heat...

29 CFR 1919.17 - Exemptions from heat treatment.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 7 2011-07-01 2011-07-01 false Exemptions from heat treatment. 1919.17 Section 1919.17... from heat treatment. Gear made of steel, or gear which contains (as in ball bearings swivels), or is permanently attached to (as with blocks) equipment made of materials which cannot be subjected to heat...

30 CFR 717.18 - Dams constructed of or impounding waste material.

Code of Federal Regulations, 2011 CFR

2011-07-01

... shall design, locate, construct, operate, maintain, modify, and abandon or remove all dams (used either... design. (ix) A permanent identification marker, at least 6 feet high that shows the dam number assigned... located on or immediately adjacent to each dam within 30 days of certification of design pursuant to this...

"Can" the Black Box

ERIC Educational Resources Information Center

Lestingi, Francis S.

1975-01-01

Describes the use of the "Arcane (mysterious) Can" which is a "tin" can which is permanently sealed, both air- and water-tight, by means of a home canning device. The canning procedure permits the use of a large variety of materials which can not be utilized in the ordinary mystery box. This Can activity is valuable for…

Embodied Humanism: Performative Argument for Natural Rights in "The Solitude of Self."

ERIC Educational Resources Information Center

Stormer, Nathan

1999-01-01

Discusses how Elizabeth Cady Stanton's "The Solitude of Self" grounds rights in the material paradox of chance life events and the corporeal permanence of human isolation by enacting human solitude through what J. Campbell calls lyric tragedy. Reverses the ground for humanism from the disembodied rationalism of the Enlightenment to an…

49 CFR 173.10 - Tank car shipments.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 2 2012-10-01 2012-10-01 false Tank car shipments. 173.10 Section 173.10... SHIPMENTS AND PACKAGINGS General § 173.10 Tank car shipments. (a) Tank cars containing any 2.1 material... facilities which have been equipped for piping the liquid from tank cars to permanent storage tanks of...

49 CFR 173.10 - Tank car shipments.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 2 2011-10-01 2011-10-01 false Tank car shipments. 173.10 Section 173.10... SHIPMENTS AND PACKAGINGS General § 173.10 Tank car shipments. (a) Tank cars containing any 2.1 material... facilities which have been equipped for piping the liquid from tank cars to permanent storage tanks of...

49 CFR 173.10 - Tank car shipments.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 2 2013-10-01 2013-10-01 false Tank car shipments. 173.10 Section 173.10... SHIPMENTS AND PACKAGINGS General § 173.10 Tank car shipments. (a) Tank cars containing any 2.1 material... facilities which have been equipped for piping the liquid from tank cars to permanent storage tanks of...

49 CFR 173.10 - Tank car shipments.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 2 2014-10-01 2014-10-01 false Tank car shipments. 173.10 Section 173.10... SHIPMENTS AND PACKAGINGS General § 173.10 Tank car shipments. (a) Tank cars containing any 2.1 material... facilities which have been equipped for piping the liquid from tank cars to permanent storage tanks of...

49 CFR 173.10 - Tank car shipments.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 2 2010-10-01 2010-10-01 false Tank car shipments. 173.10 Section 173.10... SHIPMENTS AND PACKAGINGS General § 173.10 Tank car shipments. (a) Tank cars containing any 2.1 material... facilities which have been equipped for piping the liquid from tank cars to permanent storage tanks of...

29 CFR 1919.17 - Exemptions from heat treatment.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 7 2012-07-01 2012-07-01 false Exemptions from heat treatment. 1919.17 Section 1919.17... from heat treatment. Gear made of steel, or gear which contains (as in ball bearings swivels), or is permanently attached to (as with blocks) equipment made of materials which cannot be subjected to heat...

29 CFR 1919.17 - Exemptions from heat treatment.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 7 2014-07-01 2014-07-01 false Exemptions from heat treatment. 1919.17 Section 1919.17... from heat treatment. Gear made of steel, or gear which contains (as in ball bearings swivels), or is permanently attached to (as with blocks) equipment made of materials which cannot be subjected to heat...

29 CFR 1919.17 - Exemptions from heat treatment.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 7 2013-07-01 2013-07-01 false Exemptions from heat treatment. 1919.17 Section 1919.17... from heat treatment. Gear made of steel, or gear which contains (as in ball bearings swivels), or is permanently attached to (as with blocks) equipment made of materials which cannot be subjected to heat...

75 FR 7631 - Notice of Environmental Assessment Related to the Issuance of a License Amendment to Byproduct...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-22

... unsealed Hydrogen-3 and Carbon-14 for use during in-vitro research labeling activities. However, through... Hydrogen-3 was the only licensed material used in the facility. The licensee permanently ceased licensed... licensee's historical review of past research activities determined that Hydrogen-3 was the only...

Permanent Visual Change Associated with Punctate Foveal Lesions,

DTIC Science & Technology

1986-03-01

Resources, National Research Council. This material has been reviewed by Letterman Army Institute of Research and there is no objection to its presentation...OrIDist swia SPEC, 4 -Zwick et al .4.D DETECTOR MIRROR I DIFFUSER FRONT SURFACE OSLD ND MIRROR LASER SHUTTER 3 REAM No FILTERr-: SPLIT7ER L3 C

33 CFR 157.122 - Piping, valves, and fittings.

Code of Federal Regulations, 2010 CFR

2010-07-01

... OIL IN BULK Crude Oil Washing (COW) System on Tank Vessels Design, Equipment, and Installation § 157..., valves, and fittings of each COW system must: (1) Meet 46 CFR part 56; and (2) Be of steel or an equivalent material accepted by the Commandant. (b) The piping of each COW system must be permanently...

Linking Grain Boundary Microstructure to Stress Corrosion Cracking of Cold Rolled Alloy 690 in PWR Primary Water

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

Bruemmer, Stephen M.; Olszta, Matthew J.; Toloczko, Mychailo B.

2012-10-01

Grain boundary microstructures and microchemistries are examined in cold-rolled alloy 690 tubing and plate materials and comparisons are made to intergranular stress corrosion cracking (IGSCC) behavior in PWR primary water. Chromium carbide precipitation is found to be a key aspect for materials in both the mill annealed and thermally treated conditions. Cold rolling to high levels of reduction was discovered to produce small IG voids and cracked carbides in alloys with a high density of grain boundary carbides. The degree of permanent grain boundary damage from cold rolling was found to depend directly on the initial IG carbide distribution. Formore » the same degree of cold rolling, alloys with few IG precipitates exhibited much less permanent damage. Although this difference in grain boundary damage appears to correlate with measured SCC growth rates, crack tip examinations reveal that cracked carbides appeared to blunt propagation of IGSCC cracks in many cases. Preliminary results suggest that the localized grain boundary strains and stresses produced during cold rolling promote IGSCC susceptibility and not the cracked carbides and voids.« less

Similarities and differences in coatings for magnesium-based stents and orthopaedic implants

PubMed Central

Ma, Jun; Thompson, Marc; Zhao, Nan; Zhu, Donghui

2016-01-01

Magnesium (Mg)-based biodegradable materials are promising candidates for the new generation of implantable medical devices, particularly cardiovascular stents and orthopaedic implants. Mg-based cardiovascular stents represent the most innovative stent technology to date. However, these products still do not fully meet clinical requirements with regards to fast degradation rates, late restenosis, and thrombosis. Thus various surface coatings have been introduced to protect Mg-based stents from rapid corrosion and to improve biocompatibility. Similarly, different coatings have been used for orthopaedic implants, e.g., plates and pins for bone fracture fixation or as an interference screw for tendon-bone or ligament-bone insertion, to improve biocompatibility and corrosion resistance. Metal coatings, nanoporous inorganic coatings and permanent polymers have been proved to enhance corrosion resistance; however, inflammation and foreign body reactions have also been reported. By contrast, biodegradable polymers are more biocompatible in general and are favoured over permanent materials. Drugs are also loaded with biodegradable polymers to improve their performance. The key similarities and differences in coatings for Mg-based stents and orthopaedic implants are summarized. PMID:27695671

Design of an unmanned lunar cargo lander that reconfigures into a shelter for a habitation module or disassembles into parts useful to a permanent manned lunar base

NASA Technical Reports Server (NTRS)

Davanay, Lisa; Garner, Brian; Rigol, Jason

1989-01-01

NASA plans to establish a permanent manned lunar base by the first decade of the twenty-first century. It is extremely expensive to transport material from earth to the moon. Therefore, expense would be reduced if the vehicle that lands cargo on the moon could itself meet some of the material needs of establishing the lunar base. The design of a multi-functional lander that is entirely useful to the base after landing is described. Alternate designs of the overall lander configuration and possible uses of the lander and its components after landing are contained. The design solution is a lander employing the Saddlebagged Fuel Tank Configuration. After landing, its structure will be converted into a habitation module shelter that supports a protective layer of regolith. The fuel tanks will be cleaned and used as storage tanks for the lunar base. The engines and instrumentation will be saved as stock parts. Recommendations for further research and technology development to enhance future lander designs are given.

Early working memory as a racially and ethnically neutral measure of outcome in extremely preterm children at 18-22 months

PubMed Central

Lowe, Jean R.; Duncan, Andrea Freeman; Bann, Carla M.; Fuller, Janell; Hintz, Susan R.; Das, Abhik; Higgins, Rosemary D.; Watterberg, Kristi L.

2013-01-01

Background Difficulties with executive function has been found in preterm children, resulting in difficulties with learning and school performance. Aim This study evaluated the relationship of early working memory as measured by object permanence items to the cognitive and language scores on the Bayley Scales-III in a cohort of children born extremely preterm. Study Design Logistic regression models were conducted to compare object permanence scores derived from the Bayley Scales-III by race/ethnicity and maternal education, controlling for medical covariates. Subjects Extremely preterm toddlers (526), who were part of a Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network's multi-center study, were evaluated at 18-22 months corrected age. Outcome Measures Object permanence scores derived from the Bayley Developmental Scales were compared by race/ethnicity and maternal education, controlling for medical covariates. Results There were no significant differences in object permanence mastery and scores among the treatment groups after controlling for medical and social variables, including maternal education and race/ethnicity. Males and children with intraventricular hemorrhage, retinopathy of prematurity, and bronchopulmonary dysplasia were less likely to demonstrate object permanence mastery and had lower object permanence scores. Children who attained object permanence mastery had significantly higher Bayley Scales-III cognitive and language scores after controlling for medical and socio-economic factors. Conclusions Our measure of object permanence is free of influence from race, ethnic and socio-economic factors. Adding this simple task to current clinical practice could help detect early executive function difficulties in young children. PMID:23993309

Permanent magnetic field, direct electric field, and infrared to reduce blood glucose level and hepatic function in mus musculus with diabetic mellitus

NASA Astrophysics Data System (ADS)

Suhariningsih; Basuki Notobroto, Hari; Winarni, Dwi; Achmad Hussein, Saikhu; Anggono Prijo, Tri

2017-05-01

Blood contains several electrolytes with positive (cation) and negative (anion) ion load. Both electrolytes deliver impulse synergistically adjusting body needs. Those electrolytes give specific effect to external disturbance such as electric, magnetic, even infrared field. A study has been conducted to reduce blood glucose level and liver function, in type 2 Diabetes Mellitus patients, using Biophysics concept which uses combination therapy of permanent magnetic field, electric field, and infrared. This study used 48 healthy mice (mus musculus), male, age 3-4 weeks, with approximately 25-30 g in weight. Mice was fed with lard as high fat diet orally, before Streptozotocin (STZ) induction become diabetic mice. Therapy was conducted by putting mice in a chamber that emits the combination of permanent magnetic field, electric field, and infrared, every day for 1 hour for 28 days. There were 4 combinations of therapy/treatment, namely: (1) permanent magnetic field, direct electric field, and infrared; (2) permanent magnetic field, direct electric field, without infrared; (3) permanent magnetic field, alternating electric field, and infrared; and (4) permanent magnetic field, alternating electric field, without infrared. The results of therapy show that every combination is able to reduce blood glucose level, AST, and ALT. However, the best result is by using combination of permanent magnetic field, direct electric field, and infrared.

Individual differences in object permanence performance at 8 months: locomotor experience and brain electrical activity.

PubMed

Bell, M A; Fox, N A

1997-12-01

This work was designed to investigate individual differences in hands-and-knees crawling and frontal brain electrical activity with respect to object permanence performance in 76 eight-month-old infants. Four groups of infants (one prelocomotor and 3 with varying lengths of hands-and-knees crawling experience) were tested on an object permanence scale in a research design similar to that used by Kermoian and Campos (1988). In addition, baseline EEG was recorded and used as an indicator of brain development, as in the Bell and Fox (1992) longitudinal study. Individual differences in frontal and occipital EEG power and in locomotor experience were associated with performance on the object permanence task. Infants successful at A-not-B exhibited greater frontal EEG power and greater occipital EEG power than unsuccessful infants. In contrast to Kermoian and Campos (1988), who noted that long-term crawling experience was associated with higher performance on an object permanence scale, infants in this study with any amount of hands and knees crawling experience performed at a higher level on the object permanence scale than prelocomotor infants. There was no interaction among brain electrical activity, locomotor experience, and object permanence performance. These data highlight the value of electrophysiological research and the need for a brain-behavior model of object permanence performance that incorporates both electrophysiological and behavioral factors.

Radiological impact of phosphogypsum discharged into the Venice lagoon: 222Rn

NASA Astrophysics Data System (ADS)

Cantaluppi, C.; Ceccotto, F.; Cianchi, A.; Fasson, A.; Degetto, S.

2012-04-01

For about 20 years, between the 60 's and the 80 's of the last century, in the Passo a Campalto area (Lagoon of Venice - Italy) about 400,000 m3 of phosphogypsum (PG) were deposited at the border of the lagoon and next to urban areas without any environmental control. These materials are a by-product formed during the wet processing of phosphate rocks by sulphuric acid and have a significant environmental impact due to their abundance and their chemical-physical and radiochemical characteristics. The PG contains both chemical elements, which are considered dangerous for the ecosystems and natural radionuclides whose concentrations are much higher if compared to those typical for the Earth's crust. These discarded materials caused for many years the dispersion of radionuclides in the environment due to the tidal erosion, the re-suspension of radioactive inhalable dusts, the uncontrolled radon exhalation and the bioaccumulation of some radionuclides in the lagoon environment. After a decision of the appointed authorities, the Venice Water Authority (Ministry of Infrastructure and Transport), planned a permanent safety control of the site resulting in the complete isolation of the entire volume of contaminated materials from the environmental system. The entire project was specific for the particular features of the site and it required the improvement of analytical, sampling and measurement techniques in order to verify the effectiveness of the safety action. The radon assessment, in particular the check of the effectiveness of the inhibition of radon exhalation, is part of a more complex study, covering many other aspects of the management of a permanent disposal; they will be the object of further notes. The ultimate results of this study prove the efficacy of the intervention: radon concentrations in air and exhalation values from the restored area, measured during surveys, have been proved to be well in agreement with those of non contaminated soils.

How the University of Texas system responded to the need for interim storage of low-level radioactive waste materials.

PubMed

Emery, Robert J

2012-11-01

Faced with the prospect of being unable to permanently dispose of low-level radioactive wastes (LLRW) generated from teaching, research, and patient care activities, component institutions of the University of Texas System worked collaboratively to create a dedicated interim storage facility to be used until a permanent disposal facility became available. Located in a remote section of West Texas, the University of Texas System Interim Storage Facility (UTSISF) was licensed and put into operation in 1993, and since then has provided safe and secure interim storage for up to 350 drums of dry solid LLRW at any given time. Interim storage capability provided needed relief to component institutions, whose on-site waste facilities could have possibly become overburdened. Experiences gained from the licensing and operation of the site are described, and as a new permanent LLRW disposal facility emerges in Texas, a potential new role for the storage facility as a surge capacity storage site in times of natural disasters and emergencies is also discussed.

A Progressive Damage Model for Predicting Permanent Indentation and Impact Damage in Composite Laminates

NASA Astrophysics Data System (ADS)

Ji, Zhaojie; Guan, Zhidong; Li, Zengshan

2017-10-01

In this paper, a progressive damage model was established on the basis of ABAQUS software for predicting permanent indentation and impact damage in composite laminates. Intralaminar and interlaminar damage was modelled based on the continuum damage mechanics (CDM) in the finite element model. For the verification of the model, low-velocity impact tests of quasi-isotropic laminates with material system of T300/5228A were conducted. Permanent indentation and impact damage of the laminates were simulated and the numerical results agree well with the experiments. It can be concluded that an obvious knee point can be identified on the curve of the indentation depth versus impact energy. Matrix cracking and delamination develops rapidly with the increasing impact energy, while considerable amount of fiber breakage only occurs when the impact energy exceeds the energy corresponding to the knee point. Predicted indentation depth after the knee point is very sensitive to the parameter μ which is proposed in this paper, and the acceptable value of this parameter is in range from 0.9 to 1.0.

Magnetic properties of bulk, and rapidly solidified nanostructured (Nd 1-xCe x) 2Fe 14-yCo yB ribbons

DOE PAGES

Pathak, Arjun K.; Khan, M.; Gschneidner, Jr., K. A.; ...

2015-11-06

Magnetic properties of Ce and Co co-doped (Nd 1-xCe x) 2Fe 14-yCo yB compounds have been investigated both in bulk polycrystalline and rapidly solidified nanostructured ribbon forms. For certain Ce concentrations the materials exhibit spin re-orientation transitions below 140 K. The Curie temperatures, saturation magnetizations, and other magnetic properties relevant for applications as permanent magnets are controlled by Ce and Co substitutions for Nd and Fe, respectively. Most importantly, the results show that Ce, Co co-doped compounds are excellent replacements for several Dy-based high performance permanent magnets (dysprosium is one of the critical elements and is, therefore, in short supply).more » As a result, the high temperature (>375 K) magnetic properties for Nd–Ce–Fe–Co–B based alloys show promise not only as a replacement for Dy-doped Nd 2Fe 14B permanent magnets, but the new alloys also require significantly lower amounts of Nd, which too is the critical element that can be replaced by a more abundant Ce.« less

Chemical approaches to carbon dioxide utilization for manned Mars missions

NASA Technical Reports Server (NTRS)

Hepp, Aloysius F.; Landis, Geoffrey A.; Kubiak, Clifford P.

1991-01-01

Use of resources available in situ is a critical enabling technology for a permanent human presence in space. A permanent presence on Mars, e.g., requires a large infrastructure to sustain life under hostile conditions. As a resource on Mars, atmospheric CO2 is as follows: abundant; available at all points on the surface; of known presence; chemically simple; and can be obtained by simple compression. Many studies focus on obtaining O2 and the various uses for O2 including life support and fuel; discussion of CO, the coproduct from CO2 fixation revolves around its uses as a fuel, being oxidized back to CO2. Several new proposals are studied for CO2 fixation through chemical, photochemical, and photoelectrochemical means. For example, the reduction of CO2 to hydrocarbons such as acetylene (C2H2) can be accomplished with H2. C2H2 has a theoretical vacuum specific impulse of approx. 375 secs. Potential uses were also studied of CO2, as obtained or further reduced to carbon, as a reducing agent in metal oxide processing to form metals or metal carbides for use as structural or power materials; the CO2 can be recycled to generate O2 and CO.

Histological Evaluation of Allium sativum Oil as a New Medicament for Pulp Treatment of Permanent Teeth.

PubMed

Mohammad, Shukry Gamal; Raheel, Syed Ahmed; Baroudi, Kusai

2015-02-01

The objective of this study was to evaluate the histo pathology effects of two medicaments Allium sativum oil and formocresol on the remaining pulp tissue of the permanent teething children. A total of 18 premolars were included in this study. Two sound premolars were extracted and subjected to histological examination to show the normal pulp tissue. Pulpo tomy procedure was performed in the rest of the remaining 16 premolars; half of them using Allium sativum oil and the rest of the tested premolars were medicated using formocresol and all were sealed with suitable restoration. Then, premolars extracted at variable intervals (48 hours, 2 weeks, 1 month, 2 months), stained using hemotoxylin and eosin etain (H&E) and prepared for histopathology examination. Histological evaluation seemed far more promising for Allium sativum oil than formocresol. Histological evaluation revealed that teeth treated with Allium sativa oil showed infammatory changes that had been resolved in the end of the study. On the contrary, the severe chronic infammation of pulp tissue accompanied with formocresol eventually produced pulp necrosis with or without fibrosis. In addition, pulp calcification was evidenced in certain cases. Allium sativum oil is a biocompatible material that is compatible with vital human pulp tissue. It offers a good healing potential, leaving the remaining pulp tissue healthy and functioning.

Shimming Halbach magnets utilizing genetic algorithms to profit from material imperfections.

PubMed

Parker, Anna J; Zia, Wasif; Rehorn, Christian W G; Blümich, Bernhard

2016-04-01

In recent years, permanent magnet-based NMR spectrometers have resurfaced as low-cost portable alternatives to superconducting instruments. While the development of these devices as well as clever shimming methods have yielded impressive advancements, scaling the size of these magnets to miniature lengths remains a problem to be addressed. Here we present the results of a study of a discrete shimming scheme for NMR Mandhalas constructed from a set of individual magnet blocks. While our calculations predict a modest reduction in field deviation by a factor of 9.3 in the case of the shimmed ideal Mandhala, a factor of 28 is obtained in the case of the shimmed imperfect Mandhala. This indicates that imperfections of magnet blocks can lead to improved field homogeneity. We also present a new algorithm to improve the homogeneity of a permanent magnet assembly. Strategies for future magnet construction can improve the agreement between simulation and practical implementation by using data from real magnets in these assemblies as the input to such an algorithm to optimize the homogeneity of a given design. Published by Elsevier Inc.

Safety and efficiency of flow diverters for treating small intracranial aneurysms: A systematic review and meta-analysis.

PubMed

Yao, Xiyang; Ma, Junwei; Li, Haiying; Shen, Haitao; Lu, Xiaojun; Chen, Gang

2017-02-01

Background We evaluated the safety and efficiency of flow diverters (FDs) in treating small intracranial aneurysms (IAs). Materials and Methods We reviewed the literature published in PubMed and EMBASE. R for Project software was used to calculate the complete aneurysm occlusion rates, procedure-related neurologic mortality, procedure-related neurologic morbidity and procedure-related permanent morbidity. Results Ten observational studies were included in this analysis. The complete aneurysm occlusion rate was 84.23% (80.34%-87.76%), the procedure-related neurologic mortality was 0.87% (0.29%-1.74%), the procedure-related neurologic morbidity rate was 5.22% (3.62%-7.1%), the intracerebral haemorrhage rate was 1.42% (0.64%-2.49%), the ischemic rate was 2.35% (1.31%-3.68%), the subarachnoid haemorrhage rate was 0.03% (0%-0.32%) and the procedure-related permanent morbidity was 2.41% (0.81%-4.83%). Conclusions Treatment of small IAs with FDs may be correlated with high complete occlusion rates and low complication rates. Future long-term follow-up randomized trials will determine the optimal treatment for small IAs.

Permanent medialization of the paralyzed vocal fold utilizing botulinum toxin and Gelfoam.

PubMed

Rontal, Eugene; Rontal, Michael

2003-09-01

The clinical picture of a paralyzed vocal fold often has the same appearance as a subluxated arytenoid, with anterior and medial displacement of the arytenoid and a foreshortened and lax vocal fold. Previous work by the authors has shown that a subluxated arytenoid may be permanently repositioned by reduction and selective injection of the intrinsic laryngeal musculature with botulinum toxin. The injection changes the forces within the larynx, allowing the arytenoid to be brought back to proper position on the cricoid cartilage. This concept has been extended to the paralyzed vocal fold. It has been noted that even a clinically paralyzed vocal fold has voluntary motor units that may still act on the arytenoid through residual action from the interarytenoid and synkinesis. These forces are significant enough to manipulate the arytenoid and, thus, the vocal fold, into its correct, adducted position. In this paper, the arytenoid is mobilized to free any fibrosis. The thyroarytenoid and lateral cricoarytenoid muscles are then injected to prevent any forward synkinetic pull on the arytenoid. Next, a Gelfoam injection medializes the vocal fold to create glottic closure. This rebalancing sufficiently positions the arytenoid, so that valvular function is permanently restored. In the ten patients studied for over 1 year, there was a 90% success rate as measured by videostroboscopy, phonation time, and V-RQOL analysis. There were no untoward complications. All the materials used are nonpermanent. The procedure does not limit other techniques from being performed at a later time.

Poster — Thur Eve — 41: Considerations for Patients with Permanently Implant Radioactive Sources Requiring Unrelated Surgery

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

Basran, P. S; Beckham, WA; Baxter, P

Permanent implant of sealed radioactive sources is an effective technique for treating cancer. Typically, the radioactive sources are implanted in and near the disease, depositing dose locally over several months. There may be instances where these patients must undergo unrelated surgical procedures when the radioactive material remains active enough to pose risks. This work explores these risks, discusses strategies to mitigate those risks, and describes a case study for a permanent I-125 prostate brachytherapy implant patient who developed colo-rectal cancer and required surgery 6 months after brachytherapy. The first consideration is identifying the risk from unwarranted radiation to the patientmore » and staff before, during, and after the surgical procedure. The second is identifying the risk the surgical procedure may have on the efficacy of the brachytherapy implant. Finally, there are considerations for controlling for radioactive substances from a regulatory perspective. After these risks are defined, strategies to mitigate those risks are considered. These strategies may include applying the concepts of ALARA, the use of protective equipment and developing a best practice strategy with the operating room team. We summarize this experience with some guidelines: If the surgical procedure is near (ex: 5 cm) of the implant; and, the surgical intervention may dislodge radioisotopes enough to compromise treatment or introduces radiation safety risks; and, the radioisotope has not sufficiently decayed to background levels; and, the surgery cannot be postponed, then a detailed analysis of risk is advised.« less

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

Aoki, K.; Fujii, N.; Kageyama, H.

Durability of selected hard materials as information preserving media has been studied, leading to some promising results. Several engraving experiments on the selected materials confirmed that characters and patterns can be expressed along with shading and gradation. Engraving experiments on durable artificial materials were carried out by applying laser technologies. By selecting appropriate materials and engraving methods, characters and patterns can be expressed along with shading and gradation. These technologies can be applied to not only documentary records but also to markers and monuments. Among the materials, silicon carbide, which has strong resistance against heat wear and chemical impacts, corrosionmore » resistance and wear resistance, showed satisfactory results in terms of accuracy. Thus, it is expected to be a promising material for the long-term record preservation. With respect to the density of characters in written records in the case of dot printing, it was estimated that, with 2-point characters, information totaling 6 to 8 pages of A-4 size can be engraved on a 10 cm x 10 cm plate. When a document that has 500 pages of A4 size paper is engraved on sintered silicon carbide plates, the total volume of recording media is evaluated as follows: - Size of plate: 10 cm x 10 cm; - Size of character to be engraved: 2-points ({approx} 0.7 mm; of readable size by naked eye or using a magnifying glass); - Number of pages of original document to be engraved on a plate: 8; - Number of pages of original document to be engraved on both sides of a plate: 16; - Number of plates needed for a series of document package: 500 / 16 = 32; - The thickness of a plate: 1 mm; - The total thickness of recording media: 32 mm; - Bulk of recording media preserving 500 pages of document: 10 cm x 10 cm x 32 cm. The examination has shown the possibility of long-term preservation of documentation records as a permanent system. A further examination is suggested concerning the assessment of the durability of the sintered silicon carbide plate against wear and chemical impacts. Preserving color pictures and photographs for a long-term duration is also proposed. In conclusion: We have proposed that the concept of a record preservation system is the combination of several different methods in order to impart redundancy to the communication function. The system should be robust that its overall function would not be influenced by partial damage, and also be flexible enough to adapt to the changes of background conditions in the future. Records and information should be preserved by way of both Relay System and Permanent System. The former would maintain record preservation and communication functions in the framework of social systems whereas the latter would consist of durable storehouse facilities, recording media and markers/monuments and be independent of any social systems and human control. Silicon carbide is one of the most promising materials for the Permanent System of Records Preservation. It is expected to be the potential candidate for long-term recording media with its superior characteristics of resistance against heat, wear and chemical impacts, and of engraving accuracy. (authors)« less

Faster sensitivity and non-antimonite permanent photoresist for MEMS

NASA Astrophysics Data System (ADS)

Misumi, Koichi; Saito, Koji; Yamanouchi, Atsushi; Senzaki, Takahiro; Okui, Toshiki; Honma, Hideo

2006-03-01

Micro Electro Mechanical Systems (MEMS) is a three-dimensional micro-fabrication technology based on photolithography. The fields of application are extensive and wide-ranging. Among the applications, those that have already acquired a large market include acceleration sensors for airbags of automobiles, pressure sensors for engine control, inkjet printer heads and thin film magnetic heads. The market is expected to further expand in the optic and biology-related fields in the future. In the MEMS field, the packaging accounts for the cost, and it is difficult to standardize due to the low production volume of highly specific technology application. A typical application in the MEMS process would be to conduct plating and etching (Deep RIE) through an intermediate layer of photoresist patterns, but there are cases where the photoresist itself is left therein as a permanent film. A photoresist composed of epoxy resin as the main component can form the permanent film through a catalyst of the optical cationic polymerizating initiator. In general, the optical cationic polymerizating initiator is of onium salt with antimonite as the anion group due to the nature of the hardening rate or the exposure energy. This paper presents the development status of a high sensitivity permanent photoresist made of epoxy resin as the main component with non-antimonite optical cationic polymerizating initiator with concerns to the impact to the environment and material for packaging.

Viking magnetic properties investigation: preliminary results.

PubMed

Hargraves, R B; Collinson, D W; Spitzer, C R

1976-10-01

Three permanent magnet arrays are aboard the Viking lander. By sol 35, one array, fixed on a photometric reference test chart on top of the lander, has clearly attracted magnetic particles from airborne dust; two other magnet arrays, one strong and one weak, incorporated in the backhoe of the surface sampler, have both extracted considerable magnetic mineral from the surface as a result of nine insertions associated with sample acquisition. The loose martian surface material around the landing site is judged to contain 3 to 7 percent highly magnetic mineral which, pending spectrophotometric study, is thought to be mainly magnetite.

Dental Glass Ionomer Cements as Permanent Filling Materials? —Properties, Limitations Future Trends

PubMed Central

Lohbauer, Ulrich

2009-01-01

Glass ionomer cements (GICs) are clinically attractive dental materials that have certain unique properties that make them useful as restorative and luting materials. This includes adhesion to moist tooth structures and base metals, anticariogenic properties due to release of fluoride, thermal compatibility with tooth enamel, biocompatibility and low toxicity. The use of GICs in a mechanically loaded situation, however, has been hampered by their low mechanical performance. Poor mechanical properties, such as low fracture strength, toughness and wear, limit their extensive use in dentistry as a filling material in stress-bearing applications. In the posterior dental region, glass ionomer cements are mostly used as a temporary filling material. The requirement to strengthen those cements has lead to an ever increasing research effort into reinforcement or strengthening concepts.

Spent Nuclear Fuel Disposition

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

Wagner, John C.

One interdisciplinary field devoted to achieving the end-state of used nuclear fuel (UNF) through reuse and/or permanent disposal. The reuse option aims to make use of the remaining energy content in UNF and reduce the amount of long-lived radioactive materials that require permanent disposal. The planned approach in the U.S., as well as in many other countries worldwide, is direct permanent disposal in a deep geologic repository. Used nuclear fuel is fuel that has been irradiated in a nuclear reactor to the point where it is no longer capable of sustaining operational objectives. The vast majority (by mass) of UNFmore » is from electricity generation in commercial nuclear power reactors. Furthermore, the other main source of UNF in the U.S. is the Department of Energy’s (DOE) and other federal agencies’ operation of reactors in support of federal government missions, such as materials production, nuclear propulsion, research, testing, and training. Upon discharge from a reactor, UNF emits considerable heat from radioactive decay. Some period of active on-site cooling (e.g., 2 or more years) is typically required to facilitate efficient packaging and transportation to a disposition facility. Hence, the field of UNF disposition broadly includes storage, transportation and ultimate disposition. See also: Nuclear Fission (content/nuclear-fission/458400), Nuclear Fuels (/content/nuclear-fuels/458600), Nuclear Fuel Cycle (/content/nuclear-fuel-cycle/458500), Nuclear Fuels Reprocessing (/content/nuclear-fuels-reprocessing/458700), Nuclear Power (/content/nuclear-power/459600), Nuclear Reactor (/content/nuclear-reactor/460100), Radiation (/content/radiation/566300), and Radioactive Waste Management (/content/radioactive-waste-management/568900).« less

Spent Nuclear Fuel Disposition

DOE PAGES

Wagner, John C.

2016-05-22

One interdisciplinary field devoted to achieving the end-state of used nuclear fuel (UNF) through reuse and/or permanent disposal. The reuse option aims to make use of the remaining energy content in UNF and reduce the amount of long-lived radioactive materials that require permanent disposal. The planned approach in the U.S., as well as in many other countries worldwide, is direct permanent disposal in a deep geologic repository. Used nuclear fuel is fuel that has been irradiated in a nuclear reactor to the point where it is no longer capable of sustaining operational objectives. The vast majority (by mass) of UNFmore » is from electricity generation in commercial nuclear power reactors. Furthermore, the other main source of UNF in the U.S. is the Department of Energy’s (DOE) and other federal agencies’ operation of reactors in support of federal government missions, such as materials production, nuclear propulsion, research, testing, and training. Upon discharge from a reactor, UNF emits considerable heat from radioactive decay. Some period of active on-site cooling (e.g., 2 or more years) is typically required to facilitate efficient packaging and transportation to a disposition facility. Hence, the field of UNF disposition broadly includes storage, transportation and ultimate disposition. See also: Nuclear Fission (content/nuclear-fission/458400), Nuclear Fuels (/content/nuclear-fuels/458600), Nuclear Fuel Cycle (/content/nuclear-fuel-cycle/458500), Nuclear Fuels Reprocessing (/content/nuclear-fuels-reprocessing/458700), Nuclear Power (/content/nuclear-power/459600), Nuclear Reactor (/content/nuclear-reactor/460100), Radiation (/content/radiation/566300), and Radioactive Waste Management (/content/radioactive-waste-management/568900).« less

Design Issues for Using Magnetic Materials in Radiation Environments at Elevated Temperature

NASA Technical Reports Server (NTRS)

Bowman, Cheryl L.

2013-01-01

One of the challenges of designing motors and alternators for use in nuclear powered space missions is accounting for the effects of radiation. Terrestrial reactor power plants use distance and shielding to minimize radiation damage but space missions must economize volume and mass. Past studies have shown that sufficiently high radiation levels can affect the magnetic response of hard and soft magnetic materials. Theoretical models explaining the radiation-induced degradation have been proposed but not verified. This paper reviews the literature and explains the cumulative effects of temperature, magnetic-load, and radiation-level on the magnetic properties of component materials. Magnetic property degradation is very specific to alloy choice and processing history, since magnetic properties are very much entwined with specific chemistry and microstructural features. However, there is basic theoretical as well as supportive experimental evidence that the negative impact to magnetic properties will be minimal if the bulk temperature of the material is less than fifty percent of the Curie temperature, the radiation flux is low, and the demagnetization field is small. Keywords: Magnets, Permanent Magnets, Power Converters, Nuclear Electric Power Generation, Radiation Tolerance.

Dental treatment needs of permanent first molars in mashhad schoolchildren.

PubMed

Ebrahimi, Masoumeh; Ajami, Behjat-Al-Molook; Sarraf Shirazi, Ali Reza; Afzal Aghaee, Monavar; Rashidi, Somayeh

2010-01-01

In spite of their enormous importance, permanent first molars might be affected by caries in children in developing countries. The aim of this study was to evaluate the treatment needs of first permanent molars in a group of schoolchildren in Mashhad. This cross-sectional descriptive study was carried out on 700, 7-9 year-old students in primary schools in Mashhad. The schools were randomly selected from each district. Treatment needs and DMFT of first perma-nent molars were calculated. Data was analyzed using ANOVA, Chi-Square and t-test. A total of 95.3% of the children required dental treatment. Fissure sealant application and filling were the treat-ments most required in all age groups. The mean DMFT of first permanent molars was 1.31±1.4. It was significantly higher in girls than boys (P=0.040). Great treatment needs and caries prevalence in permanent first molars in Mashhad schoolchildren show that dental caries is still a serious problem in the children of our society; therefore, education of parents and teachers is necessary for promoting children's oral health.

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.

Energy Saving Melting and Revert Reduction Technology (Energy-SMARRT): Light Metals Permanent Mold Casting

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

Fasoyinu, Yemi

2014-03-31

Current vehicles use mostly ferrous components for structural applications. It is possible to reduce the weight of the vehicle by substituting these parts with those made from light metals such as aluminum and magnesium. Many alloys and manufacturing processes can be used to produce these light metal components and casting is known to be most economical. One of the high integrity casting processes is permanent mold casting which is the focus of this research report. Many aluminum alloy castings used in automotive applications are produced by the sand casting process. Also, aluminum-silicon (Al-Si) alloys are the most widely used alloymore » systems for automotive applications. It is possible that by using high strength aluminum alloys based on an aluminum-copper (Al-Cu) system and permanent mold casting, the performance of these components can be enhanced significantly. This will also help to further reduce the weight. However, many technological obstacles need to be overcome before using these alloys in automotive applications in an economical way. There is very limited information in the open literature on gravity and low-pressure permanent mold casting of high strength aluminum alloys. This report summarizes the results and issues encountered during the casting trials of high strength aluminum alloy 206.0 (Al-Cu alloy) and moderate strength alloy 535.0 (Al-Mg alloy). Five engineering components were cast by gravity tilt-pour or low pressure permanent mold casting processes at CanmetMATERIALS (CMAT) and two production foundries. The results of the casting trials show that high integrity engineering components can be produced successfully from both alloys if specific processing parameters are used. It was shown that a combination of melt processing and mold temperature is necessary for the elimination of hot tears in both alloys.« less

Soapnut extract mediated synthesis of nanoscale cobalt substituted NdFeB ferromagnetic materials and their characterization

NASA Astrophysics Data System (ADS)

Rao, G. V. S. Jayapala; Prasad, T. N. V. K. V.; Shameer, Syed; Rao, M. Purnachandra

2018-04-01

Neodymium iron boron (NdFeB) permanent magnets have high energy product with suitable magnetic and physical properties for an array of applications including power generation and motors. However, synthetic routes of NdFeB permanent magnets involve critical procedures with high energy and needs scientific skills. Herein, we report on soapnut extract mediated synthesis of nanoscale cobalt substituted NdFeB (Co-NdFeB) permanent magnetic powders (Nd: 15%, Fe: 77.5%, B: 7.5% and Co with molar ratios: 0.5, 1, 1.5 and 2). A 10 ml of 10% soapnut extract was added to 90 ml of respective chemical composition and heated to 60 °C for 30 min and aged for 24 h. The dried powder was sintered at 500 °C for 1 h. The characterization of the prepared nanoscale Co-NdFeB magnetic powders was done using the techniques such as Dynamic Light Scattering (DLS for size and zeta potential measurements), X-ray diffraction (XRD) for structural determination, Scanning electron microscopy (SEM) with energy dispersion spectroscopy (EDS) for surface morphological and elemental analysis, Fourier transform infrared spectroscopy (FT-IR) for the identification of functional groups associated and hysteresis loop studies to quantify the magnetization. The results revealed that particles were in irregular and tubular shaped and highly stable (Zeta potential: -44.4 mV) with measured size <100 nm. XRD micrographs revealed a tetragonal crystal structure and FTIR showed predominant N-H and O-H stretching indicates the involvement of these functional groups in the reduction and stabilization process of Co-NdFeB magnetic powders. Hysteresis studies signify the effect of an increase in Co concentration.