Experimental study of the maximum resolution and packing density achievable in sintered and non-sintered binder-jet 3D printed steel microchannels

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

Elliott, Amy M; Mehdizadeh Momen, Ayyoub; Benedict, Michael

2015-01-01

Developing high resolution 3D printed metallic microchannels is a challenge especially when there is an essential need for high packing density of the primary material. While high packing density could be achieved by heating the structure to the sintering temperature, some heat sensitive applications require other strategies to improve the packing density of primary materials. In this study the goal is to develop high green or pack densities microchannels on the scale of 2-300 microns which have a robust mechanical structure. Binder-jet 3D printing is an additive manufacturing process in which droplets of binder are deposited via inkjet into amore » bed of powder. By repeatedly spreading thin layers of powder and depositing binder into the appropriate 2D profiles, complex 3D objects can be created one layer at time. Microchannels with features on the order of 500 microns were fabricated via binder jetting of steel powder and then sintered and/or infiltrated with a secondary material. The average particle size of the steel powder was varied along with the droplet volume of the inkjet-deposited binder. The resolution of the process, packing density of the primary material, the subsequent features sizes of the microchannels, and the overall microchannel quality were characterized as a function of particle size distribution, droplet sizes and heat treatment temperatures.« less

Ductile mandrel and parting compound facilitate tube drawing

NASA Technical Reports Server (NTRS)

Burt, W. R., Jr.; Mayfield, R. M.; Polakowski, N. H.

1966-01-01

Refractory tubing is warm drawn over a solid ductile mandrel with a powder parting compound packed between mandrel and the tubes inner surface. This method applies also to the coextrusion of a billet and a ductile mandrel.

Improved blend and tablet properties of fine pharmaceutical powders via dry particle coating.

PubMed

Huang, Zhonghui; Scicolone, James V; Han, Xi; Davé, Rajesh N

2015-01-30

The improvements in the flow and packing of fine pharmaceutical powder blends due to dry coating of micronized acetaminophen (mAPAP, ∼11μm), a model poorly flowing drug, are quantified. Poor flow and packing density of fine excipients (∼20μm) allowed testing the hypothesis that dry coating of cohesive API may counteract poor flow and packing of fine pharmaceutical powder blends. Further, fine excipients could improve compaction and reduce segregation tendency. It was found that flow function coefficient (FFC) and bulk density enhancements for 10%, 30%, and 60% (w/w), API loading blends with dry coated API are significantly higher than those without coated silica. At the highest API loading, for which coarser excipients were also used as reference, the flow and packing of dry coated mAPAP blends were significantly increased regardless of the excipient particle size, exceeding those of a well compacting excipient, Avicel 102. In addition, tensile strength of tablets with fine excipients was significantly higher, indicating improved compactibility. These results show for the first time that dry coating of fine, cohesive API powder leads to significantly improved flow and packing of high API loading blends consisting of fine excipients, while achieving improved tablet compactibility, suggesting suitability for direct compaction. Copyright © 2014 Elsevier B.V. All rights reserved.

Improved compaction of dried tannery wastewater sludge.

PubMed

Della Zassa, M; Zerlottin, M; Refosco, D; Santomaso, A C; Canu, P

2015-12-01

We quantitatively studied the advantages of improving the compaction of a powder waste by several techniques, including its pelletization. The goal is increasing the mass storage capacity in a given storage volume, and reducing the permeability of air and moisture, that may trigger exothermic spontaneous reactions in organic waste, particularly as powders. The study is based on dried sludges from a wastewater treatment, mainly from tanneries, but the indications are valid and useful for any waste in the form of powder, suitable to pelletization. Measurements of bulk density have been carried out at the industrial and laboratory scale, using different packing procedures, amenable to industrial processes. Waste as powder, pellets and their mixtures have been considered. The bulk density of waste as powder increases from 0.64 t/m(3) (simply poured) to 0.74 t/m(3) (tapped) and finally to 0.82 t/m(3) by a suitable, yet simple, packing procedure that we called dispersion filling, with a net gain of 28% in the compaction by simply modifying the collection procedure. Pelletization increases compaction by definition, but the packing of pellets is relatively coarse. Some increase in bulk density of pellets can be achieved by tapping; vibration and dispersion filling are not efficient with pellets. Mixtures of powder and pellets is the optimal packing policy. The best compaction result was achieved by controlled vibration of a 30/70 wt% mixture of powders and pellets, leading to a final bulk density of 1t/m(3), i.e. an improvement of compaction by more than 54% with respect to simply poured powders, but also larger than 35% compared to just pellets. That means increasing the mass storage capacity by a factor of 1.56. Interestingly, vibration can be the most or the least effective procedure to improve compaction of mixtures, depending on characteristics of vibration. The optimal packing (30/70 wt% powders/pellets) proved to effectively mitigate the onset of smouldering, leading to self-heating, according to standard tests, whereas the pure pelletization totally removes the self-heating hazard. Copyright © 2015 Elsevier Ltd. All rights reserved.

Accelerated stability studies of Sufoofe Sailan: A Unani formulation

PubMed Central

Rani, Seema; Rahman, Khaleequr; Younis, Peerzada Mohammad

2015-01-01

Introduction: Sufoofe Sailan (SS) is a polyherbal powder preparation used in Unani medicine to treat gynecological diseases. It is observed that SS degrade early as it is in the form of powder; however, the stability study of SS was not carried out till date. Aim: To evaluate the accelerated stability of SS. Materials and Methods: Finished formulation of SS was packed in three airtight transparent polyethylene terephthalate containers. One pack was analyzed just after manufacturing and remaining two packs were kept in stability chamber at 40°C ± 2°C/75% ± 5% RH, of which one pack was analyzed after the completion of three and another after 6 months. Organoleptic, physico-chemical, microbiological parameters along with high-performance thin layer chromatography (HPTLC) fingerprinting were carried out. Results: Organoleptic characters showed no significant change in accelerated stability condition. All physico-chemical parameters showed changes <5%, HPTLC fingerprinting showed minimum changes and microbial studies were in confirmation to the World Health Organization guidelines. Conclusion: SS confirmed to the International Conference on Harmonization Guideline for accelerated testing of the pharmaceutical product on said parameters and as per the Grimm's statement the shelf life of SS may last 20 months. PMID:26730145

49 CFR 173.171 - Smokeless powder for small arms.

Code of Federal Regulations, 2010 CFR

2010-10-01

... boxes meeting the Packing Group I performance level, provided all inside containers are packed to prevent shifting and the net weight of smokeless powder in any one box does not exceed 7.3 kg (16 pounds...) net mass in: (1) One rail car, motor vehicle, or cargo-only aircraft; or (2) One freight container on...

49 CFR 173.171 - Smokeless powder for small arms.

Code of Federal Regulations, 2014 CFR

2014-10-01

... fiberboard boxes meeting the Packing Group I performance level, provided all inside containers are packed to prevent shifting and the net weight of smokeless powder in any one box does not exceed 7.3 kg (16 pounds... 45.4 kg (100 pounds) net mass in: (1) One rail car, motor vehicle, or cargo-only aircraft; or (2) One...

49 CFR 173.171 - Smokeless powder for small arms.

Code of Federal Regulations, 2011 CFR

2011-10-01

... boxes meeting the Packing Group I performance level, provided all inside containers are packed to prevent shifting and the net weight of smokeless powder in any one box does not exceed 7.3 kg (16 pounds...) net mass in: (1) One rail car, motor vehicle, or cargo-only aircraft; or (2) One freight container on...

49 CFR 173.171 - Smokeless powder for small arms.

Code of Federal Regulations, 2012 CFR

2012-10-01

... boxes meeting the Packing Group I performance level, provided all inside containers are packed to prevent shifting and the net weight of smokeless powder in any one box does not exceed 7.3 kg (16 pounds...) net mass in: (1) One rail car, motor vehicle, or cargo-only aircraft; or (2) One freight container on...

Preparation, chemical composition and storage studies of quamachil (Pithecellobium dulce L.) aril powder.

PubMed

Rao, Galla Narsing; Nagender, Allani; Satyanarayana, Akula; Rao, Dubasi Govardhana

2011-02-01

Quamachil aril powder samples were prepared and evaluated for chemical composition and sensory quality by packing in two packaging systems during storage for six months. The protein contents were 12.4 and 15.0% in white and pink aril powders respectively. The titrable acidity of white and pink aril powders were 2.4 and 4.8% respectively. Ca and Fe contents in white aril powder samples were 60 and 12 mg/100 g where as in pink aril powder 62 and 16 mg/100 g, respectively. The anthocyanin content in pink powder decreased from 50.5 to 11.2 and 14.1 mg/100 g in samples packed in polyethylene (PE) and metalised polyester polyethylene laminated pouches respectively. Total polyphenol amount increased in both the powders irrespective of packaging material. Sorption isotherms indicated that both white and pink aril powders were hygroscopic and equilibrated at low relative humidity of 28 and 32%, respectively.

Sensitivity of energy-packed compounds based on superfine and nanoporous silicon to pulsed electrical treatments

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

Zegrya, G. G.; Savenkov, G. G.; Morozov, V. A.

2017-04-15

The sensitivity of an energy-packed compound based on nanoporous silicon and calcium perchlorate to a high-current electron beam is studied. The initiation of explosive transformations in a mixture of potassium picrate with a highly dispersed powder of boron-doped silicon by means of a high-voltage discharge is examined. It is shown that explosive transformation modes (combustion and explosion) appear in the energy-packed compound under study upon its treatment with an electron beam. A relationship is established between the explosive transformation modes and the density of the energy-packed compound and between the breakdown (initiation) voltage and the mass fraction of the siliconmore » powder.« less

Numerical simulation on the powder propellant pickup characteristics of feeding system at high pressure

NASA Astrophysics Data System (ADS)

Sun, Haijun; Hu, Chunbo; Zhu, Xiaofei

2017-10-01

A numerical study of powder propellant pickup progress at high pressure was presented in this paper by using two-fluid model with kinetic theory of granular flow in the computational fluid dynamics software package ANSYS/Fluent. Simulations were conducted to evaluate the effects of initial pressure, initial powder packing rate and mean particle diameter on the flow characteristics in terms of velocity vector distribution, granular temperature, pressure drop, particle velocity and volume. The numerical results of pressure drop were also compared with experiments to verify the TFM model. The simulated results show that the pressure drop value increases as the initial pressure increases, and the granular temperature under the conditions of different initial pressures and packing rates is almost the same in the area of throttling orifice plate. While there is an appropriate value for particle size and packing rate to form a ;core-annulus; structure in powder box, and the time-averaged velocity vector distribution of solid phase is inordinate.

Numerical simulation and parametric analysis of selective laser melting process of AlSi10Mg powder

NASA Astrophysics Data System (ADS)

Pei, Wei; Zhengying, Wei; Zhen, Chen; Junfeng, Li; Shuzhe, Zhang; Jun, Du

2017-08-01

A three-dimensional numerical model was developed to investigate effects of laser scanning speed, laser power, and hatch spacing on the thermodynamic behaviors of the molten pool during selective laser melting of AlSi10Mg powder. A randomly distributed packed powder bed was achieved using discrete element method (DEM). The powder bed can be treated as a porous media with interconnected voids in the simulation. A good agreement between numerical results and experimental results establish the validity of adopted method. The numerical results show that the Marangoni flow within the molten pool was significantly affected by the processing parameters. An intense Marangoni flow leads to a perturbation within the molten pool. In addition, a relatively high scanning speed tends to cause melt instability. The perturbation or the instability within the molten pool results in the formation of pores during SLM, which have a direct influence on the densification level.

Silica powders for powder evacuated thermal insulating panel and method

DOEpatents

Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

1996-01-01

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Silica powders for powder evacuated thermal insulating panel and method

DOEpatents

Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

1994-01-01

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2 /g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Silica powders for powder evacuated thermal insulating panel and method

DOEpatents

Harris, Michael T.; Basaran, Osman A.; Kollie, Thomas G.; Weaver, Fred J.

1995-01-01

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm.sup.3 and an external surface area in the range of about 90 to 600 m.sup.2/ g is described. The silica powders are prepared by reacting a tetraakyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders.

Silica powders for powder evacuated thermal insulating panel and method

DOEpatents

Harris, M.T.; Basaran, O.A.; Kollie, T.G.; Weaver, F.J.

1996-01-02

A powder evacuated thermal insulating panel using generally spherical and porous silica particles of a median size less than about 100 nanometers in diameter, a pour packing density of about 0.4 to 0.6 g/cm{sup 3} and an external surface area in the range of about 90 to 600 m{sup 2}/g is described. The silica powders are prepared by reacting a tetraalkyl silicate with ammonia and water in an alcohol solvent, distilling the solution after the reaction to remove the ammonia and recover the alcohol. The resulting aqueous slurry was dried, ball-milled, and dried again to provide the silica particles with defined internal and external porosity. The nanometer size and the large external surface area of the silica particles along with the internal and external porosity of the silica particles provide powder evacuated thermal insulating panels with significantly higher R-values than obtainable using previously known silica powders. 2 figs.

Effects of Sample Preparation on the Infrared Reflectance Spectra of Powders

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

Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.

2015-05-22

While reflectance spectroscopy is a useful tool in identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-packedmore » as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.« less

Effects of sample preparation on the infrared reflectance spectra of powders

NASA Astrophysics Data System (ADS)

Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.; Su, Yin-Fong; Blake, Thomas A.; Forland, Brenda M.

2015-05-01

While reflectance spectroscopy is a useful tool for identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-loaded as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample can have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.

21 CFR 176.350 - Tamarind seed kernel powder.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Tamarind seed kernel powder. 176.350 Section 176... Paperboard § 176.350 Tamarind seed kernel powder. Tamarind seed kernel powder may be safely used as a component of articles intended for use in producing, manufacturing, packing, processing, preparing, treating...

Primary packaging considerations in developing medicines for children: oral liquid and powder for constitution.

PubMed

Campbell, Gossett A; Vallejo, Erick

2015-01-01

The packaging presentation of oral liquid pediatric medicines is a critical step in maintaining chemical and physical stability, compliance, adherence, and proper handling by the target patient population, guardians, caregivers, and health-care professionals. The common packaging presentations for commercial oral liquid pediatric drug products are glass bottle, plastic bottle, sachet, and stick pack configurations. The type of pack presentation selected is driven by the quality target product profile (QTPP) that is designed around the physicochemical properties of the drug substance and the desired drug product suitability for the target population. The QTPP defines the intended use of the drug product, drug product quality criteria, dose strength, dosage form, container closure system, storage conditions, stability criteria, dosing device, shelf life, and attributes affecting the pharmacokinetic characteristics. Oral liquid pediatric formulations are typically prepared from a powder that is constituted at the time of use as a suspension or a solution for single or multiple use depending on the stability of the constituted formulation. Active ingredients with high aqueous solubility can be developed as a powder for oral solution and presented in a bottle for multiple use product and a stick pack, packet, or sachet for single-use product. Active ingredients with low aqueous solubility can be developed as a powder for oral suspension and presented in a bottle for multiple use product and a stick pack or sachet for single-use product. A secondary package may be used in cases where the primary pack failed to provide adequate protection against light degradation. This work will help formulation scientists select the most appropriate pack presentation in the early stages of pediatric clinical development. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

The influence of Cr and Al pack cementation on low carbon steel to improve oxidation resistance

NASA Astrophysics Data System (ADS)

Prasetya, Didik; Sugiarti, Eni; Destyorini, Fredina; Thosin, Kemas Ahmad Zaini

2012-06-01

Pack chromizing and aluminizing has been widely used for many years to improve hot temperature oxidation and corrosion resistance of metals. The coating process involves packing the steel in a powder mixture which contain aluminum and chromium source, and inert filler (usually alumina), and halide activator NH4Cl. Al and Cr were deposited onto carbon steel by pack cementation process using elemental Al and Cr powder as Al and Cr source, whereas NiCo alloys codeposited by electrodeposition. The position of Al and Cr could be under or over Ni-Co alloys deposited. Pack cementation was heated on dry inert gas at temperature 800 °C about 5 hours and 20 minute for Cr and Al respectively. Al and Cr was successfully deposited. Laying down effect of Al and Cr onto carbon steel whether up and down toward NiCo alloys coating have affected to oxidation resistance. The pack aluminizing as top layer given best resitance to restrain excessive oxide scale, in contrast pack chromizing reveal bad oxidation resistance, moreover occured spallation on layer.

Steric stabilization of nonaqueous silicon slips. I - Control of particle agglomeration and packing. II - Pressure casting of powder compacts

NASA Technical Reports Server (NTRS)

Kerkar, Awdhoot V.; Henderson, Robert J. M.; Feke, Donald L.

1990-01-01

The application of steric stabilization to control particle agglomeration and packing of silicon powder in benzene and trichloroethylene is reported. The results provide useful guidelines for controlling unfavorable particle-particle interactions during nonaqueous processing of silicon-based ceramic materials. The application of steric stabilization to the control and improvement of green processing of nonaqueous silicon slips in pressure consolidation is also demonstrated.

Effects of oral powder electrolyte administration on packed cell volume, plasma chemistry parameters, and incidence of colic in horses participating in a 6-day 162-km trail ride

PubMed Central

Walker, Wade T.; Callan, Robert J.; Hill, Ashley E.; Tisher, Kelly B.

2014-01-01

This study evaluated the effects of administering oral powder electrolytes on packed cell volume (PCV), plasma chemistry parameters, and incidence of colic in horses participating on a 6-day 162-km trail ride in which water was not offered ad libitum. Twenty-three horses received grain with powder electrolytes daily while 19 control horses received grain only. Horses were ridden approximately 32 km a day at a walk or trot. Packed cell volume and plasma chemistry parameters were analyzed daily. Episodes of colic were diagnosed and treated by a veterinarian unaware of treatment group allocation. Blood parameters and incidence of colic were compared between treatment groups. Electrolyte administration did not alter PCV or plasma chemistry parameters compared to controls. The incidence of colic was significantly higher in treated horses (P = 0.05). Oral powder electrolytes did not enhance hydration status or electrolyte homeostasis and may be associated with colic in horses participating on long distance trail rides similar to this model. PMID:25082992

Effects of oral powder electrolyte administration on packed cell volume, plasma chemistry parameters, and incidence of colic in horses participating in a 6-day 162-km trail ride.

PubMed

Walker, Wade T; Callan, Robert J; Hill, Ashley E; Tisher, Kelly B

2014-08-01

This study evaluated the effects of administering oral powder electrolytes on packed cell volume (PCV), plasma chemistry parameters, and incidence of colic in horses participating on a 6-day 162-km trail ride in which water was not offered ad libitum. Twenty-three horses received grain with powder electrolytes daily while 19 control horses received grain only. Horses were ridden approximately 32 km a day at a walk or trot. Packed cell volume and plasma chemistry parameters were analyzed daily. Episodes of colic were diagnosed and treated by a veterinarian unaware of treatment group allocation. Blood parameters and incidence of colic were compared between treatment groups. Electrolyte administration did not alter PCV or plasma chemistry parameters compared to controls. The incidence of colic was significantly higher in treated horses (P = 0.05). Oral powder electrolytes did not enhance hydration status or electrolyte homeostasis and may be associated with colic in horses participating on long distance trail rides similar to this model.

Molecular packing and magnetic properties of lithium naphthalocyanine crystals: hollow channels enabling permeability and paramagnetic sensitivity to molecular oxygen

PubMed Central

Pandian, Ramasamy P.; Dolgos, Michelle; Marginean, Camelia; Woodward, Patrick M.; Hammel, P. Chris; Manoharan, Periakaruppan T.; Kuppusamy, Periannan

2009-01-01

The synthesis, structural framework, magnetic and oxygen-sensing properties of a lithium naphthalocyanine (LiNc) radical probe are presented. LiNc was synthesized in the form of a microcrystalline powder using a chemical method and characterized by electron paramagnetic resonance (EPR) spectroscopy, magnetic susceptibility, powder X-ray diffraction analysis, and mass spectrometry. X-Ray powder diffraction studies revealed a structural framework that possesses long, hollow channels running parallel to the packing direction. The channels measured approximately 5.0 × 5.4 Å2 in the two-dimensional plane perpendicular to the length of the channel, enabling diffusion of oxygen molecules (2.9 × 3.9 Å2) through the channel. The powdered LiNc exhibited a single, sharp EPR line under anoxic conditions, with a peak-to-peak linewidth of 630 mG at room temperature. The linewidth was sensitive to surrounding molecular oxygen, showing a linear increase in pO2 with an oxygen sensitivity of 31.2 mG per mmHg. The LiNc microcrystals can be further prepared as nano-sized crystals without the loss of its high oxygen-sensing properties. The thermal variation of the magnetic properties of LiNc, such as the EPR linewidth, EPR intensity and magnetic susceptibility revealed the existence of two different temperature regimes of magnetic coupling and hence differing columnar packing, both being one-dimensional antiferromagnetic chains but with differing magnitudes of exchange coupling constants. At a temperature of ∼50 K, LiNc crystals undergo a reversible phase transition. The high degree of oxygen-sensitivity of micro- and nano-sized crystals of LiNc, combined with excellent stability, should enable precise and accurate measurements of oxygen concentration in biological systems using EPR spectroscopy. PMID:19809598

Thermal behavior in single track during selective laser melting of AlSi10Mg powder

NASA Astrophysics Data System (ADS)

Wei, Pei; Wei, Zhengying; Chen, Zhen; He, Yuyang; Du, Jun

2017-09-01

A three-dimensional model was developed to simulate the radiation heat transfer in the AlSi10Mg packed bed. The volume of fluid method (VOF) was used to capture the free surface during selective laser melting (SLM). A randomly packed powder bed was obtained using discrete element method (DEM) in Particle Flow Code (PFC). The proposed model has demonstrated a high potential to simulate the selective laser melting process (SLM) with high accuracy. In this paper, the effect of the laser scanning speed and laser power on the thermodynamic behavior of the molten pool was investigated numerically. The results show that the temperature gradient and the resultant surface tension gradient between the center and the edge of the molten pool increase with decreasing the scanning speed or increasing the laser power, thereby intensifying the Marangoni flow and attendant turbulence within the molten pool. However, at a relatively high scanning speed, a significant instability may be generated in the molten pool. The perturbation and instability in the molten pool during SLM may result in an irregular shaped track.

Method for immobilizing particulate materials in a packed bed

DOEpatents

Even, W.R. Jr.; Guthrie, S.E.; Raber, T.N.; Wally, K.; Whinnery, L.L.; Zifer, T.

1999-02-02

The present invention pertains generally to immobilizing particulate matter contained in a packed bed reactor so as to prevent powder migration, compaction, coalescence, or the like. More specifically, this invention relates to a technique for immobilizing particulate materials using a microporous foam-like polymer such that (a) the particulate retains its essential chemical nature, (b) the local movement of the particulate particles is not unduly restricted, (c) bulk powder migration and is prevented, (d) physical and chemical access to the particulate is unchanged over time, and (e) very high particulate densities are achieved. The immobilized bed of the present invention comprises a vessel for holding particulate matter, inlet and an outlet ports or fittings, a loosely packed bed of particulate material contained within the vessel, and a three dimensional porous matrix for surrounding and confining the particles thereby fixing the movement of an individual particle to a limited local position. The established matrix is composed of a series of cells or chambers comprising walls surrounding void space, each wall forming the wall of an adjacent cell; each wall containing many holes penetrating through the wall yielding an overall porous structure and allowing useful levels of gas transport. 4 figs.

Method for immobilizing particulate materials in a packed bed

DOEpatents

Even, Jr., William R.; Guthrie, Stephen E.; Raber, Thomas N.; Wally, Karl; Whinnery, LeRoy L.; Zifer, Thomas

1999-01-01

The present invention pertains generally to immobilizing particulate matter contained in a "packed" bed reactor so as to prevent powder migration, compaction, coalescence, or the like. More specifically, this invention relates to a technique for immobilizing particulate materials using a microporous foam-like polymer such that a) the particulate retains its essential chemical nature, b) the local movement of the particulate particles is not unduly restricted, c) bulk powder migration and is prevented, d) physical and chemical access to the particulate is unchanged over time, and e) very high particulate densities are achieved. The immobilized bed of the present invention comprises a vessel for holding particulate matter, inlet and an outlet ports or fittings, a loosely packed bed of particulate material contained within the vessel, and a three dimensional porous matrix for surrounding and confining the particles thereby fixing the movement of individual particle to a limited local position. The established matrix is composed of a series of cells or chambers comprising walls surrounding void space, each wall forming the wall of an adjacent cell; each wall containing many holes penetrating through the wall yielding an overall porous structure and allowing useful levels of gas transport.

Powder Bed Layer Characteristics: The Overseen First-Order Process Input

NASA Astrophysics Data System (ADS)

Mindt, H. W.; Megahed, M.; Lavery, N. P.; Holmes, M. A.; Brown, S. G. R.

2016-08-01

Powder Bed Additive Manufacturing offers unique advantages in terms of manufacturing cost, lot size, and product complexity compared to traditional processes such as casting, where a minimum lot size is mandatory to achieve economic competitiveness. Many studies—both experimental and numerical—are dedicated to the analysis of how process parameters such as heat source power, scan speed, and scan strategy affect the final material properties. Apart from the general urge to increase the build rate using thicker powder layers, the coating process and how the powder is distributed on the processing table has received very little attention to date. This paper focuses on the first step of every powder bed build process: Coating the process table. A numerical study is performed to investigate how powder is transferred from the source to the processing table. A solid coating blade is modeled to spread commercial Ti-6Al-4V powder. The resulting powder layer is analyzed statistically to determine the packing density and its variation across the processing table. The results are compared with literature reports using the so-called "rain" models. A parameter study is performed to identify the influence of process table displacement and wiper velocity on the powder distribution. The achieved packing density and how that affects subsequent heat source interaction with the powder bed is also investigated numerically.

Power packs: A passive approach to extinguishing fire in combat vehicles

NASA Astrophysics Data System (ADS)

Finnerty, Anthony E.; Polyanski, Stanley

1991-01-01

Thin (12.7 and 6.4 mm) panels of fire extinguishing powder in a honeycomb matrix were tested for their ability to extinguish fires in the FAASV ammunition resupply vehicle. These powder packs were applied to the exterior of hydraulic fluid reservoirs and fuel cells for protection from hydrocarbon fires caused by shaped charge jets penetrating the fluid containers. It was found that a surround of 12.7-mm-thick panels was required to achieve a sub 250-ms fire-out time with no second-degree burns expected to personnel with hot hydraulic fluid reservoirs. Power packs as thin as 6.4 mm provided the same protection in the case of hot diesel fuel.

Wound infection prophylaxis in pediatric acute appendicitis: a 26-year prospective study.

PubMed

Ein, Sigmund H; Sandler, Anthony

2006-03-01

The purpose of this study was to determine the best wound infection prophylaxis in pediatric acute appendicitis. From 1969 to 1995 inclusive, 453 consecutive pediatric patients at the same children's hospital had an appendix with acute inflammation (acute appendicitis) removed by the same staff surgeon and his resident. The stump was not inverted, and chromic catgut was used throughout. No intraperitoneal antibiotics, irrigation, or drains were used, and the skin closure was with silk sutures initially and then with staples since 1986. The infants and children were divided into 6 consecutive groups of 52 to 96 patients, with each group lasting 2 to 5 years. The wound treatment groups were as follows: no treatment, drain or pack, drain or pack plus antibiotic powder, antibiotic powder, preoperative intravenous antibiotic plus antibiotic powder, and preoperative intravenous antibiotic. The wound Penrose drain, one half-inch gauze pack, and/or antibiotic powder (ampicillin, 1977-1981; cefoxitin, 1982-1995) were all placed in the subcutaneous space. There were a total of 50 (11%) wound infections (pus) that occurred between 4 and 40 days when no antibiotic powder was used and 2 to 14 days with antibiotic powder. In all 6 groups of patients, no organism was grown in most (80%) infections and Escherichia coli was the second commonest (12%). The serous ooze, which occurred only with the use of antibiotic powder (8%), was seen between 6 and 18 days, and no organism was ever cultured. The patients with preoperative (or intraoperative) intravenous antibiotics (cefoxitin) plus wound antibiotic powder (cefoxitin) had the lowest infection rate (2.5%). When this group was compared with the baseline group 1 (no treatment), it was the only group in which wound treatment made a significant difference (P = .003).

7 CFR 160.93 - Powdered rosin.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS FOR NAVAL STORES Labeling, Advertising and Packing § 160.93 Powdered rosin. The classification and grade of any rosin sold in commerce in a powdered or finely broken condition shall be stated in the... broken. For the purpose of preventing coalescence there may be incorporated in such article a limited and...

7 CFR 160.93 - Powdered rosin.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS FOR NAVAL STORES Labeling, Advertising and Packing § 160.93 Powdered rosin. The classification and grade of any rosin sold in commerce in a powdered or finely broken condition shall be stated in the... broken. For the purpose of preventing coalescence there may be incorporated in such article a limited and...

7 CFR 160.93 - Powdered rosin.

Code of Federal Regulations, 2014 CFR

2014-01-01

... STANDARDS FOR NAVAL STORES Labeling, Advertising and Packing § 160.93 Powdered rosin. The classification and grade of any rosin sold in commerce in a powdered or finely broken condition shall be stated in the... broken. For the purpose of preventing coalescence there may be incorporated in such article a limited and...

7 CFR 160.93 - Powdered rosin.

Code of Federal Regulations, 2013 CFR

2013-01-01

... STANDARDS FOR NAVAL STORES Labeling, Advertising and Packing § 160.93 Powdered rosin. The classification and grade of any rosin sold in commerce in a powdered or finely broken condition shall be stated in the... broken. For the purpose of preventing coalescence there may be incorporated in such article a limited and...

Quality Assurance of Current Combat Ration Pack Components: 12 Months Progress Report on 2010/11 Ration Packing Program

DTIC Science & Technology

2013-04-01

Cream of Chicken Soup, Marmalade, Orange Sports Powder, Grape Sports Powder, Banana Berry Candy, Musk Candy, Tomato Ketchup and Sweet Chilli Sauce...Strong Peppermint (ESP) Candy............................................... 19 3.8.3 Banana Berry Candy...M M Marmalade P P P M AR Plum Fruit Spread P P P P P Strawberry Fruit Spread P M P P P P Chocolate Candy M Banana Berry Candy P M M M M P AR Musk

Packing properties of starch-based powders under mild mechanical stress.

PubMed

Zanardi, I; Gabbrielli, A; Travagli, V

2009-07-01

This study reports the ability to settle of commercial pharmaceutical grade starch samples, both native and pregelatinized. The experiments were carried out under different relative humidity (RH%) conditions and the packing properties were evaluated using both official pharmacopoeial monograph conditions and also modified conditions in order to give a deeper knowledge of tapping under mild mechanical stress. The technique adopted, simulating common pharmaceutical operating practices, appears to be useful to estimate some technologically relevant features of diluent powder materials. Moreover, a general mathematical function has been applied to the experimental data; this could be appropriate for adequately describing material settling patterns and offers practical parameters for characterizing starch powders within the context of a pharmaceutical quality system.

Molybdeno-Aluminizing of Powder Metallurgy and Wrought Ti and Ti-6Al-4V alloys by Pack Cementation process

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

Tsipas, Sophia A., E-mail: stsipas@ing.uc3m.es; Go

Wear and high temperature oxidation resistance of some titanium-based alloys needs to be enhanced, and this can be effectively accomplished by surface treatment. Molybdenizing is a surface treatment where molybdenum is introduced into the surface of titanium alloys causing the formation of wear-resistant surface layers containing molybdenum, while aluminizing of titanium-based alloys has been reported to improve their high temperature oxidation properties. Whereas pack cementation and other surface modification methods have been used for molybdenizing or aluminizing of wrought and/or cast pure titanium and titanium alloys, such surface treatments have not been reported on titanium alloys produced by powder metallurgymore » (PM). Also a critical understanding of the process parameters for simultaneous one step molybdeno-aluminizing of titanium alloys by pack cementation and the predominant mechanism for this process have not been reported. The current research work describes the surface modification of titanium and Ti-6Al-4V prepared by PM by molybdeno-aluminizing and analyzes thermodynamic aspects of the deposition process. Similar coatings are also deposited to wrought Ti-6Al-4V and compared. Characterization of the coatings was carried out using scanning electron microscopy and x-ray diffraction. For both titanium and Ti-6Al-4V, the use of a powder pack containing ammonium chloride as activator leads to the deposition of molybdenum and aluminium into the surface but also introduces nitrogen causing the formation of a thin titanium nitride layer. In addition, various titanium aluminides and mixed titanium aluminium nitrides are formed. The appropriate conditions for molybdeno-aluminizing as well as the phases expected to be formed were successfully determined by thermodynamic equilibrium calculations. - Highlights: •Simultaneous co-deposition of Mo-Al onto powder metallurgy and wrought Ti alloy •Thermodynamic calculations were used to optimize deposition conditions •External TiN and internal a Mo-rich layer on all alloy substrates •Titanium aluminides and Ti-Al mixed nitrides are formed on Ti-6Al-4V •The presence of Al and V alloying elements modifies the diffusion of Mo.« less

Investigation of Microtubular Ceramic Structures

DTIC Science & Technology

1979-02-01

25 Experiments 05x - Excel ŗ-5 CAL" (Powder D). 25 Experiments 06x - Excel ŗ-5 CAL" (Powder D). 26 Experiments 07x - Stabilized Zirconia ( Powder E...an extremely fine particle size (- 0. 4 jim) for satisfactory sintering. With zirconia powder of this particle size, spherical aggregates formed...firm" packing pressure, sustained large additions (15 to--9 gm/cycle) occurred. Experiments 07x - Stabilized Zirconia ( Powder E) The 07x experiments

Laboratory Evaluation of Australian Ration Packs.

DTIC Science & Technology

1982-09-01

Monitoring of Freeze Dried Meals , Potato & Onion Powder .......................... 40 Appendix 6 Emergency Flying Ration ............................ 41...Moulds were enumerated using the pour plate method as described in AS 1766 Part 2.1.2 1976. On occasions malt extract agar was used in place of...potato dextrose agar . Coliforms & E. coli were enumerated using the pour plate method as described in AS 1766 Part 2.1.3.7 1976. Violet red bile dextrose

Prediction of the Effective Thermal Conductivity of Powder Insulation

NASA Astrophysics Data System (ADS)

Jin, Lingxue; Park, Jiho; Lee, Cheonkyu; Jeong, Sangkwon

The powder insulation method is widely used in structural and cryogenic systems such as transportation and storage tanks of cryogenic fluids. The powder insulation layer is constructed by small particle powder with light weight and some residual gas with high porosity. So far, many experiments have been carried out to test the thermal performance of various kinds of powder, including expanded perlite, glass microspheres, expanded polystyrene (EPS). However, it is still difficult to predict the thermal performance of powder insulation by calculation due to the complicated geometries, including various particle shapes, wide powder diameter distribution, and various pore sizes. In this paper, the effective thermal conductivity of powder insulation has been predicted based on an effective thermal conductivity calculationmodel of porous packed beds. The calculation methodology was applied to the insulation system with expanded perlite, glass microspheres and EPS beads at cryogenic temperature and various vacuum pressures. The calculation results were compared with previous experimental data. Moreover, additional tests were carried out at cryogenic temperature in this research. The fitting equations of the deformation factor of the area-contact model are presented for various powders. The calculation results show agood agreement with the experimental results.

Ceramic powder for sintering materials

NASA Technical Reports Server (NTRS)

Akiya, H.; Saito, A.

1984-01-01

Surface activity of ceramic powders such as MgO and Al2O3, for use in sintering with sp. emphasis on their particle size, shape, particle size distribution, packing, and coexisting additives and impurities are reviewed.

The effect of precipitation and calcination parameters on oxalate derived ThO2 pellets

NASA Astrophysics Data System (ADS)

Wangle, Tadeas; Tyrpekl, Vaclav; Cagno, Simone; Delloye, Thierry; Larcher, Olivier; Cardinaels, Thomas; Vleugels, Jozef; Verwerft, Marc

2017-11-01

Thorium oxalate is easy to prepare, but the derived oxide powders retain the platelet morphology of the primary oxalate. This negatively impacts packing and sintering. If powder milling is to be avoided, powder synthesis needs to be optimized. That is the goal of this paper, where different precipitation strategies were used and their effect on powder characteristics and pellet synthesis was investigated. Oxalates prepared by adding a thorium nitrate solution to an oxalic acid solution proved most promising. Further optimizing of the calcination temperature revealed that with increasing calcination temperature the packing density improved significantly. This came at the cost of decreased early stage sintering and a higher frequency of end-capping during compaction. The calcination temperature at which the highest final density can be reached was dependent on the sintering cycle. Furthermore, the ThO2 powders had less surface area and thus adsorbed less gases during storage when calcined at higher temperatures.

7 CFR 160.93 - Powdered rosin.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE (CONTINUED) NAVAL STORES REGULATIONS AND STANDARDS FOR NAVAL STORES Labeling, Advertising and Packing § 160.93 Powdered rosin. The classification and...

33. Photocopied 1983, from original drawing (DP49484), Picatinny Arsenal, November ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

33. Photocopied 1983, from original drawing (DP-49484), Picatinny Arsenal, November 29, 1948. 'SMOKELESS POWDER Area: REWORK POWDER PROCESS FLOW DIAGRAM.' THE PROCESS DETAILED IN THIS DIAGRAM FROM THE POACHING HOUSE TO THE PACK HOUSE IS SUBSTANTIALLY THE SAME AS THE ONE FOR PRODUCING NEW POWDER FROM NITRATED COTTON. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

Diversionary device

DOEpatents

Grubelich, Mark C.

2001-01-01

A diversionary device has a housing having at least one opening and containing a non-explosive propellant and a quantity of fine powder packed within the housing, with the powder being located between the propellant and the opening. When the propellant is activated, it has sufficient energy to propel the powder through the opening to produce a cloud of powder outside the housing. An igniter is also provided for igniting the cloud of powder to create a diversionary flash and bang, but at a low enough pressure to avoid injuring nearby people.

Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method.

PubMed

Ouertani, Rachid; Hamdi, Abderrahmen; Amri, Chohdi; Khalifa, Marouan; Ezzaouia, Hatem

2014-01-01

In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films.

Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method

PubMed Central

2014-01-01

In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films. PMID:25349554

Development and evaluation of garlic incorporated ready-to-eat extruded snacks.

PubMed

Haritha, D; Vijayalakshmi, V; Gulla, S

2014-11-01

The present study was carried out to develop and evaluate ready to eat extruded snacks incorporated with garlic powder at various levels (5 %, 10 %, 15 %, 20 %). The organoleptic evaluation was conducted for the developed products and the well accepted products were selected for further studies like physical properties and shelf life (stored at room temperature for 2 months). The organoleptic evaluation of the developed snacks revealed that 15 % and 20 % garlic incorporated snacks were not acceptable due to strong garlic flavor, therefore T1 (control), T2 (5 % garlic) and T3 ( 10 % garlic) were selected for further studies. The physical properties showed significant changes with incorporation of garlic powder at 0 %-10 % level. There was an increase in mass flow rate, tap density and bulk density but decrease in the water holding capacity, oil absorption capacity and expansion ratio. The water soluble index and moisture retention of the products showed the same values for all the three selected treatments. The products were packed by ordinary, nitrogen and vacuum packing and stored for 2 months. It was found that there was an increase in moisture content and microbial load, however the increase was within limits. The increase in the moisture content was low in nitrogen packed products where as the microbial load decreased with increase in the percentage of garlic incorporation. The nitrogen and vacuum packed products showed less microbial load than the ordinary packed products. Garlic powder can be incorporated at 5 and 10 % levels in ready-to-eat extruded snacks with well acceptability and can be stored for a period of 2 months with nitrogen packing as an effective packaging.

Simulation of mixture microstructures via particle packing models and their direct comparison with real mixtures

NASA Astrophysics Data System (ADS)

Gulliver, Eric A.

The objective of this thesis to identify and develop techniques providing direct comparison between simulated and real packed particle mixture microstructures containing submicron-sized particles. This entailed devising techniques for simulating powder mixtures, producing real mixtures with known powder characteristics, sectioning real mixtures, interrogating mixture cross-sections, evaluating and quantifying the mixture interrogation process and for comparing interrogation results between mixtures. A drop and roll-type particle-packing model was used to generate simulations of random mixtures. The simulated mixtures were then evaluated to establish that they were not segregated and free from gross defects. A powder processing protocol was established to provide real mixtures for direct comparison and for use in evaluating the simulation. The powder processing protocol was designed to minimize differences between measured particle size distributions and the particle size distributions in the mixture. A sectioning technique was developed that was capable of producing distortion free cross-sections of fine scale particulate mixtures. Tessellation analysis was used to interrogate mixture cross sections and statistical quality control charts were used to evaluate different types of tessellation analysis and to establish the importance of differences between simulated and real mixtures. The particle-packing program generated crescent shaped pores below large particles but realistic looking mixture microstructures otherwise. Focused ion beam milling was the only technique capable of sectioning particle compacts in a manner suitable for stereological analysis. Johnson-Mehl and Voronoi tessellation of the same cross-sections produced tessellation tiles with different the-area populations. Control charts analysis showed Johnson-Mehl tessellation measurements are superior to Voronoi tessellation measurements for detecting variations in mixture microstructure, such as altered particle-size distributions or mixture composition. Control charts based on tessellation measurements were used for direct, quantitative comparisons between real and simulated mixtures. Four sets of simulated and real mixtures were examined. Data from real mixture was matched with simulated data when the samples were well mixed and the particle size distributions and volume fractions of the components were identical. Analysis of mixture components that occupied less than approximately 10 vol% of the mixture was not practical unless the particle size of the component was extremely small and excellent quality high-resolution compositional micrographs of the real sample are available. These methods of analysis should allow future researchers to systematically evaluate and predict the impact and importance of variables such as component volume fraction and component particle size distribution as they pertain to the uniformity of powder mixture microstructures.

Final Report for X-ray Diffraction Sample Preparation Method Development

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

Ely, T. M.; Meznarich, H. K.; Valero, T.

WRPS-1500790, “X-ray Diffraction Saltcake Sample Preparation Method Development Plan/Procedure,” was originally prepared with the intent of improving the specimen preparation methodology used to generate saltcake specimens suitable for XRD-based solid phase characterization. At the time that this test plan document was originally developed, packed powder in cavity supports with collodion binder was the established XRD specimen preparation method. An alternate specimen preparation method less vulnerable, if not completely invulnerable to preferred orientation effects, was desired as a replacement for the method.

A Comparison of Cocrystal Structure Solutions from Powder and Single Crystal Techniques

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

S Lapidus; P Stephens; K Arora

We demonstrate the effectiveness and accuracy of high resolution powder diffraction for determination of cocrystal structures through a double-blind study. Structures of 10 cocrystals of varying complexity were determined independently using single crystal and powder techniques. The two methodologies give identical molecular packing and hydrogen bond topology, and an rms difference in covalent bond lengths of 0.035 {angstrom}. Powder techniques are clearly sufficient to establish a complete characterization of cocrystal geometry.

Processing study of high temperature superconducting Y-Ba-Cu-O ceramics

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

Safari, A.; Wachtman, J.B. Jr.; Ward, C.

Processing of the YBa{sub 2}Cu{sub 3}O{sub 6+x} superconducting phase by employing different precursor powder preparation techniques (ball milling, attrition milling) and samples formed by different sintering conditions are discussed. The superconducting phase has been identified by powder x-ray diffraction. The effect of different powder processing and pressing conditions on the structure, density, resistivity and a.c. magnetic susceptibility were studied. Though there is no variation in T{sub c} for all the samples, attrition milled samples show a much lower resistance and less temperature dependence compared to ball milled samples above the superconducting transition temperature up to room temperature. Ball milled samplesmore » were loosely packed with more voids compared to attrition milled samples which are more densely packed with a needle-like structure.« less

Simulation of Laser Additive Manufacturing and its Applications

NASA Astrophysics Data System (ADS)

Lee, Yousub

Laser and metal powder based additive manufacturing (AM), a key category of advanced Direct Digital Manufacturing (DDM), produces metallic components directly from a digital representation of the part such as a CAD file. It is well suited for the production of high-value, customizable components with complex geometry and the repair of damaged components. Currently, the main challenges for laser and metal powder based AM include the formation of defects (e.g., porosity), low surface finish quality, and spatially non-uniform properties of material. Such challenges stem largely from the limited knowledge of complex physical processes in AM especially the molten pool physics such as melting, molten metal flow, heat conduction, vaporization of alloying elements, and solidification. Direct experimental measurement of melt pool phenomena is highly difficult since the process is localized (on the order of 0.1 mm to 1 mm melt pool size) and transient (on the order of 1 m/s scanning speed). Furthermore, current optical and infrared cameras are limited to observe the melt pool surface. As a result, fluid flows in the melt pool, melt pool shape and formation of sub-surface defects are difficult to be visualized by experiment. On the other hand, numerical simulation, based on rigorous solution of mass, momentum and energy transport equations, can provide important quantitative knowledge of complex transport phenomena taking place in AM. The overarching goal of this dissertation research is to develop an analytical foundation for fundamental understanding of heat transfer, molten metal flow and free surface evolution. Two key types of laser AM processes are studied: a) powder injection, commonly used for repairing of turbine blades, and b) powder bed, commonly used for manufacturing of new parts with complex geometry. In the powder injection simulation, fluid convection, temperature gradient (G), solidification rate (R) and melt pool shape are calculated using a heat transfer and fluid flow model, which solves the mass, momentum and energy transport equations using the volume of fluid (VOF) method. These results provide quantitative understanding of underlying mechanisms of solidification morphology, solidification scale and deposit side bulging. In particular, it is shown that convective mixing alters solidification conditions (G and R), cooling trend and resultant size of primary dendrite arm spacing. Melt pool convexity in multiple layer LAM is associated not only with the convex shape of prior deposit but also with Marangoni flow. Lastly, it is shown that the lateral width of bulge is possibly controlled by the type of surface tension gradient. It is noted that laser beam spot size in the powder injection AM is about 2 mm and it melts hundreds of powder particles. Hence, the injection of individual particles is approximated by a lumped mass flux into the molten pool. On the other hand, for laser powder bed AM, the laser beam spot size is about 100 microm and thus it only melts a few tens of particles. Therefore, resolution of individual powder particles is essential for the accurate simulation of laser powder bed AM. To obtain the powder packing information in the powder bed, dynamic discrete element simulation (DEM) is used. It considers particle-particle interactions during packing to provide the quantitative structural powder bed properties such as particle arrangement, size and packing density, which is then an inputted as initial geometry for heat transfer and fluid flow simulation. This coupled 3D transient transport model provides a high spatial resolution while requiring less demanding computation. The results show that negatively skewed particle size distribution, faster scanning speed, low power and low packing density worsen the surface finish quality and promote the formation of balling defects. Taken together, both powder injection and powder bed models have resulted in an improved quantitative understanding of heat transfer, molten metal flow and free surface evolution. Furthermore, the analytical foundation that is developed in this dissertation provides the temperature history in AM, a prerequisite for predicting the solid-state phase transformation kinetics, residual stresses and distortion using other models. Moreover, it can be integrated with experimental monitoring and sensing tools to provide the capability of controlling melt pool shape, solidification microstructure, defect formation and surface finish.

Mg(1 + x)Ir(1 - x) (x = 0, 0.037 and 0.054), a binary intermetallic compound with a new orthorhombic structure type determined from powder and single-crystal X-ray diffraction.

PubMed

Cerný, Radovan; Renaudin, Guillaume; Favre-Nicolin, Vincent; Hlukhyy, Viktor; Pöttgen, Rainer

2004-06-01

The new binary compound Mg(1 + x)Ir(1 - x) (x = 0-0.054) was prepared by melting the elements in the Mg:Ir ratio 2:3 in a sealed tantalum tube under an argon atmosphere in an induction furnace (single crystals) or by annealing cold-pressed pellets of the starting composition Mg:Ir 1:1 in an autoclave under an argon atmosphere (powder sample). The structure was independently solved from high-resolution synchrotron powder and single-crystal X-ray data: Pearson symbol oC304, space group Cmca, lattice parameters from synchrotron powder data a = 18.46948 (6), b = 16.17450 (5), c = 16.82131 (5) A. Mg(1 + x)Ir(1 - x) is a topologically close-packed phase, containing 13 Ir and 12 Mg atoms in the asymmetric unit, and has a narrow homogeneity range. Nearly all the atoms have Frank-Kasper-related coordination polyhedra, with the exception of two Ir atoms, and this compound contains the shortest Ir-Ir distances ever observed. The solution of a rather complex crystal structure from powder diffraction, which was fully confirmed by the single-crystal method, shows the power of powder diffraction in combination with the high-resolution data and the global optimization method.

Formation of polycrystalline MgB2 synthesized by powder in sealed tube method with different initial boron phase

NASA Astrophysics Data System (ADS)

Yudanto, Sigit Dwi; Imaduddin, Agung; Kurniawan, Budhy; Manaf, Azwar

2018-04-01

Magnesium diboride, MgB2 is a new high critical temperature superconductor that discovered in the beginning of the 21st century. The MgB2 has a simple crystal structure and a high critical temperature, which can be manufactured in several forms like thin films, tapes, wires including bulk in the large scale. For that reason, the MgB2 has good prospects for various applications in the field of electronic devices. In the current work, we have explored the synthesis of MgB2 polycrystalline using powder in a sealed tube method. Different initial boron phase for the synthesized of MgB2 polycrystalline were used. These were, in addition to magnesium powders, crystalline boron, amorphous boron and combination both of them were respectively fitted in the synthesis. The raw materials were mixed in a stoichiometric ratio of Mg: B=1:2, ground using agate mortar, packed into stainless steel SS304. The pack was then sintered at temperature of 800°C for 2 hours in air atmosphere. Phase formation of MgB2 polycrystalline in difference of initial boron phase was characterized using XRD and SEM. Referring to the diffraction pattern and microstructure observation, MgB2 polycrystalline was formed, and the formation was effective when using the crystalline Mg and fully amorphous B as the raw materials. The critical temperature of the specimen was evaluated by the cryogenic magnet. The transition temperature of the MgB2 specimen synthesized using crystalline magnesium and full amorphous boron is 42.678 K (ΔTc = 0.877 K).

Effects of Precipitant and pH on Coprecipitation of Nanosized Co-Cr-V Alloy Powders.

PubMed

Chen, Xiaoyu; Li, Yongxia; Huang, Lan; Zou, Dan; Wu, Enxi; Liu, Yanjun; Xie, Yuanyan; Yao, Rui; Liao, Songyi; Wang, Guangrong; Zheng, Feng

2017-09-21

Nanosized Co-Cr-V alloy powders were synthesized via coprecipitation method. Effects of precipitants ((NH₄)₂C₂O₄·H₂O and Na₂CO₃) and pH were investigated by X-ray diffraction (XRD), Zeta potential analyzer, thermogravimetry-differential scanning calorimetry (TG-DSC), inductively coupled plasma-atomic emission spectrometry (ICP-AES) and scanning electron microscopy (SEM). Co-Cr-V alloy powders were consisted of major face-centered cubic Co (fcc Co) and minor hexagonal close-packed Co (hcp Co). Grain sizes of precursors and Co-Cr-V alloy powders were increased with pH value (7-10) within the ranges of 3~39 and 39~66 nm, respectively. Rod-like or granular Co-Cr-V alloy particles were assembled by interconnected nanograins. At pH = 7, Na₂CO₃ precipitant was found to be beneficial to maintain the desirable composition of Co-Cr-V powders. It was also found that lower pH favors the maintenance of pre-designed composition, while grain coarsens at higher pH. Effects of variation for precipitant and pH on the morphology and composition of Co-Cr-V alloy powder were discussed in detail and relevant mechanism was further proposed.

Hot isostatic pressing (HIP) of powder mixtures and composites: Packing, densification, and microstructural effects

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

Li, E.K.H.; Funkenbusch, P.D.

1993-06-01

Hot isostatic pressing (HIP) of powder mixtures (containing differently sized components) and of composite powders is analyzed. Recent progress, including development of a simple scheme for estimating radial distribution functions, has made modeling of these systems practical. Experimentally, powders containing bimodal or continuous size distributions are observed to hot isostatically press to a higher density tinder identical processing conditions and to show large differences in the densification rate as a function of density when compared with the monosize powders usually assumed for modeling purposes. Modeling correctly predicts these trends and suggests that they can be partially, but not entirely, attributedmore » to initial packing density differences. Modeling also predicts increased deformation in the smaller particles within a mixture. This effect has also been observed experimentally and is associated with microstructural changes, such as preferential recrystallization of small particles. Finally, consolidation of a composite mixture containing hard, but deformable, inclusions has been modeled for comparison with existing experimental data. Modeling results match both the densification and microstructural observations reported experimentally. Densification is retarded due to contacts between the reinforcing particles which support a significant portion of the applied pressure. In addition, partitioning of deformation between soft matrix and hard inclusion powders results in increased deformation of the softer material.« less

Injection molding ceramics to high green densities

NASA Technical Reports Server (NTRS)

Mangels, J. A.; Williams, R. M.

1983-01-01

The injection molding behavior of a concentrated suspension of Si powder in wax was studied. It was found that the injection molding behavior was a function of the processing techniques used to generate the powder. Dry ball-milled powders had the best molding behavior, while air classified and impact-milled powders demonstrated poorer injection moldability. The relative viscosity of these molding batches was studied as a function of powder properties: distribution shape, surface area, packing density, and particle morphology. The experimental behavior, in all cases, followed existing theories. The relative viscosity of an injection molding composition composed of dry ball-milled powders could be expressed using Farris' relation.

Uses of chitosan for treating different forms of serious obstetrics hemorrhages.

PubMed

Carles, G; Dabiri, C; Mchirgui, A; Saoudi, E O; Hcini, N; Pouget, K; Seve, B; de Matteis, B

2017-11-01

Postpartum hemorrhage is a major cause of maternal death worldwide. Many therapeutic strategies have been developed to reduce maternal morbidity and mortality like oxytocin, prostaglandin, and uterine balloons. A new member of the therapeutic arsenal has recently emerged, the chitosan (Celox ® ), used since several years by military doctors to stop bleeding of combat wounds. In 2012, a first study was reported with the successful use of chitosan-coated gauze to treat severe postpartum hemorrhage. We report here four cases of the use of chitosan to treat life-threatening obstetric bleeding. In the first case, a pelvic packing with chitosan gauze after hemostatic hysterectomy with persistent bleeding. In the second case, the use of chitosan powder in a case of severe bleeding from multiple vaginal tears. In the third case, the use of chitosan gauze in uterine packing for postpartum hemorrhage by atonia. In the fourth case, the use of chitosan powder for stop bleeding during a hemorrhagic cesarean section. Postpartum hemorrhage of uterine origin resistant to treatment with prostaglandins can be treated with chitosan-coated gauze. This treatment requires no training and its costs are one fifth those of a Bakri ® intrauterine balloon. Using these two forms of chitosan, powder and gauze, we have a new therapeutic method at our disposal for dealing with the most serious cases of bleeding. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Testing the limits of sensitivity in a solid-state structural investigation by combined X-ray powder diffraction, solid-state NMR, and molecular modelling.

PubMed

Filip, Xenia; Borodi, Gheorghe; Filip, Claudiu

2011-10-28

A solid state structural investigation of ethoxzolamide is performed on microcrystalline powder by using a multi-technique approach that combines X-ray powder diffraction (XRPD) data analysis based on direct space methods with information from (13)C((15)N) solid-state Nuclear Magnetic Resonance (SS-NMR) and molecular modeling. Quantum chemical computations of the crystal were employed for geometry optimization and chemical shift calculations based on the Gauge Including Projector Augmented-Wave (GIPAW) method, whereas a systematic search in the conformational space was performed on the isolated molecule using a molecular mechanics (MM) approach. The applied methodology proved useful for: (i) removing ambiguities in the XRPD crystal structure determination process and further refining the derived structure solutions, and (ii) getting important insights into the relationship between the complex network of non-covalent interactions and the induced supra-molecular architectures/crystal packing patterns. It was found that ethoxzolamide provides an ideal case study for testing the accuracy with which this methodology allows to distinguish between various structural features emerging from the analysis of the powder diffraction data. This journal is © the Owner Societies 2011

The use of functionalized monoalkyl phosphates and phosphonates in the colloidal processing of oxide ceramic powders

NASA Astrophysics Data System (ADS)

Radsick, Timothy Carl

The purpose of this study was to develop phosphorous-based chemicals that could be used to modify the interparticle pair potential of several oxide ceramic particles, thereby enabling their use in colloidal processing schemes. Several procedures for the synthesis of 11-12 carbon alpha,o-functionalized monoalkyl phosphates and phosphonates were developed. Because of its simplicity and its use of mild reagents, a procedure based on the Michaelis-Arbuzov rearrangement was selected to produce the bulk of the chemicals used in this study. Carboxyl- and hydroxyl-terminated monoalkyl phosphonates were adsorbed onto alumina and zirconia powders using either aqueous-based or solvent-based methods to produce a monolayer of "brushlike" steric molecules. In the aqueous-based methods, powders were processed at pH values below their isoelectric point in order to produce a positive charge on the powder, thereby attracting the negatively charged phosphate or phosphonate group onto the powder surface to form the steric monolayer. In solvent-based methods, powder was suspended in an acetone solution of the phosphonates, heated at reflux, washed, dried and heat treated at 120°C under vacuum. The zeta potential of the coated powders was measured to quantify the degree of steric layer adsorption and the shift in the isoelectric point. Slurries of coated alumina and zirconia were prepared having 20 vol % powder. Rheological behavior was studied by measuring viscosity as a function of shear rate for slurries of various pH values and counterion concentrations. Slurries with powder processed via the solvent method were the least sensitive to changes in slurry pH and were straightforward to prepare. It is thought that the solvent-based coating procedure produced a stronger, multi-dentate powder-phosphonate bond than that of the aqueous-based procedure. Dispersed and coagulated slurries were able to be prepared over a wide pH range, including at the isoelectric point of the uncoated powders where a flocculated slurry would typically occur. Slurries were consolidated using pressure filtration. Compressive stress-strain behavior and packing efficiencies were determined. Through consolidation, powder volume fraction was increased to a maximum of 56%, yet through vibration the slurry could be induced to flow, enabling its use in Colloidal Isopressing.

Effects of Precipitant and pH on Coprecipitation of Nanosized Co-Cr-V Alloy Powders

PubMed Central

Chen, Xiaoyu; Li, Yongxia; Huang, Lan; Zou, Dan; Wu, Enxi; Liu, Yanjun; Xie, Yuanyan; Yao, Rui; Liao, Songyi; Wang, Guangrong

2017-01-01

Nanosized Co-Cr-V alloy powders were synthesized via coprecipitation method. Effects of precipitants ((NH4)2C2O4·H2O and Na2CO3) and pH were investigated by X-ray diffraction (XRD), Zeta potential analyzer, thermogravimetry-differential scanning calorimetry (TG-DSC), inductively coupled plasma-atomic emission spectrometry (ICP-AES) and scanning electron microscopy (SEM). Co-Cr-V alloy powders were consisted of major face-centered cubic Co (fcc Co) and minor hexagonal close-packed Co (hcp Co). Grain sizes of precursors and Co-Cr-V alloy powders were increased with pH value (7–10) within the ranges of 3~39 and 39~66 nm, respectively. Rod-like or granular Co-Cr-V alloy particles were assembled by interconnected nanograins. At pH = 7, Na2CO3 precipitant was found to be beneficial to maintain the desirable composition of Co-Cr-V powders. It was also found that lower pH favors the maintenance of pre-designed composition, while grain coarsens at higher pH. Effects of variation for precipitant and pH on the morphology and composition of Co-Cr-V alloy powder were discussed in detail and relevant mechanism was further proposed. PMID:28934147

Accelerated stability studies of Sufoofe Sailan: A Unani formulation.

PubMed

Rani, Seema; Rahman, Khaleequr; Younis, Peerzada Mohammad

2015-01-01

Sufoofe Sailan (SS) is a polyherbal powder preparation used in Unani medicine to treat gynecological diseases. It is observed that SS degrade early as it is in the form of powder; however, the stability study of SS was not carried out till date. To evaluate the accelerated stability of SS. Finished formulation of SS was packed in three airtight transparent polyethylene terephthalate containers. One pack was analyzed just after manufacturing and remaining two packs were kept in stability chamber at 40°C ± 2°C/75% ± 5% RH, of which one pack was analyzed after the completion of three and another after 6 months. Organoleptic, physico-chemical, microbiological parameters along with high-performance thin layer chromatography (HPTLC) fingerprinting were carried out. Organoleptic characters showed no significant change in accelerated stability condition. All physico-chemical parameters showed changes <5%, HPTLC fingerprinting showed minimum changes and microbial studies were in confirmation to the World Health Organization guidelines. SS confirmed to the International Conference on Harmonization Guideline for accelerated testing of the pharmaceutical product on said parameters and as per the Grimm's statement the shelf life of SS may last 20 months.

Method development and validation for measuring the particle size distribution of pentaerythritol tetranitrate (PETN) powders.

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

Young, Sharissa Gay

2005-09-01

Currently, the critical particle properties of pentaerythritol tetranitrate (PETN) that influence deflagration-to-detonation time in exploding bridge wire detonators (EBW) are not known in sufficient detail to allow development of a predictive failure model. The specific surface area (SSA) of many PETN powders has been measured using both permeametry and gas absorption methods and has been found to have a critical effect on EBW detonator performance. The permeametry measure of SSA is a function of particle shape, packed bed pore geometry, and particle size distribution (PSD). Yet there is a general lack of agreement in PSD measurements between laboratories, raising concernsmore » regarding collaboration and complicating efforts to understand changes in EBW performance related to powder properties. Benchmarking of data between laboratories that routinely perform detailed PSD characterization of powder samples and the determination of the most appropriate method to measure each PETN powder are necessary to discern correlations between performance and powder properties and to collaborate with partnering laboratories. To this end, a comparison was made of the PSD measured by three laboratories using their own standard procedures for light scattering instruments. Three PETN powder samples with different surface areas and particle morphologies were characterized. Differences in bulk PSD data generated by each laboratory were found to result from variations in sonication of the samples during preparation. The effect of this sonication was found to depend on particle morphology of the PETN samples, being deleterious to some PETN samples and advantageous for others in moderation. Discrepancies in the submicron-sized particle characterization data were related to an instrument-specific artifact particular to one laboratory. The type of carrier fluid used by each laboratory to suspend the PETN particles for the light scattering measurement had no consistent effect on the resulting PSD data. Finally, the SSA of the three powders was measured using both permeametry and gas absorption methods, enabling the PSD to be linked to the SSA for these PETN powders. Consistent characterization of other PETN powders can be performed using the appropriate sample-specific preparation method, so that future studies can accurately identify the effect of changes in the PSD on the SSA and ultimately model EBW performance.« less

O the Determination of the Complex Refractive Index of Powdered Materials in the 9 TO 11 Micrometer Spectral Region Utilizing AN Attenuated Total Reflectance Technique.

NASA Astrophysics Data System (ADS)

Gillespie, James Bryce

1982-03-01

A specific method of determining the complex refractive index of powdered materials using attenuated total reflectance (ATR) spectroscopy was investigated. A very precise laser/goniometric ATR system was assembled and applied to powdered samples of carbon blacks, graphite, kaolin clay, quartz, calcite, and sodalime glass beads. The reflectivity data fell into two categories: (1) data representative of a medium having a unique effective refractive index and (2) data representative of a scattering medium having no unique refractive index. Data of the first kind were obtained from all the carbon black, graphite, and kaolin clay samples. The Fahrenfort-Visser solution of the Fresnel equations was applied to the goniometric reflectivity data for these samples to obtain the complex refractive index of these effective media. The complex refractive index obtained in this manner is not that of the bulk material but is instead a value which may be related to the bulk material value through some refractive index mixing rule. A systematic experiment using carbon black of particle size 0.0106 mm diameter was conducted to determine the applicability of several mixture rules for the volume packing fraction range of .2 to .6 which is most often encountered. The Bruggemann effective medium theory produced credible results while the Lorentz-Lorenz rule and the empirical Biot-Arago rule were invalid in this volume packing region. The Bruggemann rule was applied to lampblack, Mogul-L carbon black, graphite, and kaolin clay to obtain the complex refractive indices of these materials from the ATR spectroscopy data. Goniometric reflectivity data representative of an inhomogeneous scattering medium were obtained from all the powdered quartz, powdered calcite, and sodalime glass beads samples. These samples all contained particles with diameters nearly as large as the wavelength. These data demonstrate that the ATR technique, coupled with an effective medium analysis, may be used to obtain optical constants of powdered materials only when the particles are small compared to the wavelength.

Powder X-ray diffraction, infrared and 13C NMR spectroscopic studies of the homologous series of some solid-state zinc(II) and sodium(I) n-alkanoates

NASA Astrophysics Data System (ADS)

Nelson, Peter N.; Taylor, Richard A.

2015-03-01

A comparative study of the room temperature molecular packing and lattice structures for the homologous series of zinc(II) and sodium(I) n-alkanoates adduced from Fourier transform infrared and solid-state 13C NMR spectroscopic data in conjunction with X-ray powder diffraction measurements is carried out. For zinc carboxylates, metal-carboxyl bonding is via asymmetric bridging bidentate coordination whilst for the sodium adducts, coordination is via asymmetric chelating bidentate bonding. All compounds are packed in a monoclinic crystal system. Furthermore, the fully extended all-trans hydrocarbon chains are arranged as lamellar bilayers. For zinc compounds, there is bilayer overlap, for long chain adducts (nc > 8) but not for sodium compounds where methyl groups from opposing layers in the lamellar are only closely packed. Additionally, the hydrocarbon chains are extended along the a-axis of the unit cell for zinc compounds whilst for sodium carboxylates they are extended along the c-axis. These packing differences are responsible for different levels of Van der Waals effects in the lattices of these two series of compounds, hence, observed odd-even alternation is different. The significant difference in lattice packing observed for these two series of compounds is proposed to be due to the difference in metal-carboxyl coordination mode, arising from the different electronic structure of the central metal ions.

Synthesis and improved explosion behaviors of aluminum powders coated with nano-sized nickel film

NASA Astrophysics Data System (ADS)

Kim, Kyung Tae; Kim, Dong Won; Kim, Soo Hyung; Kim, Chang Kee; Choi, Yoon Jeong

2017-09-01

Nickel (Ni) materials with a thickness of a few hundred nm were homogeneously coated on the surfaces of aluminum (Al) powders by an electroless plating process. The Ni-coated Al powders show characteristic interfacial structures mixed of Ni, Al and O instead of densely packed Al oxide at the surface. The explosion test of the Ni-coated Al powders utilizing flame ignition showed that the powders had a 3.6 times enhanced pressurization rate of 405 kPa/ms compared to 111 kPa/ms of uncoated Al powders. It was found that this is due to a feasible diffusion of oxygen atoms into the Al powders through the thin and rough interfacial layers present at the Ni/Al interface. These results clearly indicate that nano-sized Ni film introduced instead of surface oxide acts as a very profitable layer to achieve efficient combustion behaviors by a rapid oxidation of Al powders.

Phenolic and physicochemical stability of a functional beverage powder mixture during storage: effect of the microencapsulant inulin and food ingredients.

PubMed

de Beer, Dalene; Pauck, Claire E; Aucamp, Marique; Liebenberg, Wilna; Stieger, Nicole; van der Rijst, Marieta; Joubert, Elizabeth

2018-06-01

The need for a convenience herbal iced tea product with reduced kilojoules merited investigation of the shelf-life of powder mixtures containing a green Cyclopia subternata Vogel (honeybush) extract with proven blood glucose-lowering activity and alternative sweetener mixture. Prior to long-term storage testing, the wettability of powder mixtures containing food ingredients and the compatibility of their components were confirmed using the static sessile drop method and isothermal microcalorimetry, respectively. The powders packed in semi-sealed containers remained stable during storage at 25 °C/60% relative humidity (RH) for 6 months, except for small losses of specific phenolic compounds, namely mangiferin, isomangiferin, 3-β-d-glucopyranosyliriflophenone, vicenin-2 and 3',5'-di-β-d-glucopyranosylphloretin, especially when both citric acid and ascorbic acid were present. These acids drastically increased the degradation of phenolic compounds under accelerated storage conditions (40 °C/75% RH). Accelerated storage also caused changes in the appearance of powders and the colour of the reconstituted beverage solutions. Increased moisture content and a w of the powders, as well as moisture released due to dehydration of citric acid monohydrate, contributed to these changes. A low-kilojoule honeybush iced tea powder mixture will retain its functional phenolic compounds and physicochemical properties during shelf-life storage at 25 °C for 6 months. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Magnetic power piston fluid compressor

NASA Technical Reports Server (NTRS)

Gasser, Max G. (Inventor)

1994-01-01

A compressor with no moving parts in the traditional sense having a housing having an inlet end allowing a low pressure fluid to enter and an outlet end allowing a high pressure fluid to exit is described. Within the compressor housing is at least one compression stage to increase the pressure of the fluid within the housing. The compression stage has a quantity of magnetic powder within the housing, is supported by a screen that allows passage of the fluid, and a coil for selectively providing a magnetic field across the magnetic powder such that when the magnetic field is not present the individual particles of the powder are separated allowing the fluid to flow through the powder and when the magnetic field is present the individual particles of the powder pack together causing the powder mass to expand preventing the fluid from flowing through the powder and causing a pressure pulse to compress the fluid.

On the role of heat and mass transfer into laser processability during selective laser melting AlSi12 alloy based on a randomly packed powder-bed

NASA Astrophysics Data System (ADS)

Wang, Lianfeng; Yan, Biao; Guo, Lijie; Gu, Dongdong

2018-04-01

A newly transient mesoscopic model with a randomly packed powder-bed has been proposed to investigate the heat and mass transfer and laser process quality between neighboring tracks during selective laser melting (SLM) AlSi12 alloy by finite volume method (FVM), considering the solid/liquid phase transition, variable temperature-dependent properties and interfacial force. The results apparently revealed that both the operating temperature and resultant cooling rate were obviously elevated by increasing the laser power. Accordingly, the resultant viscosity of liquid significantly reduced under a large laser power and was characterized with a large velocity, which was prone to result in a more intensive convection within pool. In this case, the sufficient heat and mass transfer occurred at the interface between the previously fabricated tracks and currently building track, revealing a strongly sufficient spreading between the neighboring tracks and a resultant high-quality surface without obvious porosity. By contrast, the surface quality of SLM-processed components with a relatively low laser power notably weakened due to the limited and insufficient heat and mass transfer at the interface of neighboring tracks. Furthermore, the experimental surface morphologies of the top surface were correspondingly acquired and were in full accordance to the calculated results via simulation.

Comparative examination of the microstructure and high temperature oxidation performance of NiCrBSi flame sprayed and pack cementation coatings

NASA Astrophysics Data System (ADS)

Chaliampalias, D.; Vourlias, G.; Pavlidou, E.; Skolianos, S.; Chrissafis, K.; Stergioudis, G.

2009-01-01

Coatings formed from NiCrBSi powder were deposited by thermal spray and pack cementation processes on low carbon steel. The microstructure and morphology of the coatings were studied by scanning electron microscopy (SEM) and X-ray diffraction analysis (XRD). Flame sprayed coatings exhibited high porosity and were mechanically bonded to the substrate while pack cementation coatings were more compact and chemically bonded to the substrate. The microhardness and the high temperature oxidation resistance of the coated samples were evaluated by a Vickers microhardness tester and by thermogravimetric measurements (TG), respectively. Pack cementation coatings showed higher hardness and were more protective to high temperature environments than the flame sprayed coatings.

Abinitio powder x-ray diffraction and PIXEL energy calculations on thiophene derived 1,4 dihydropyridine

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

Karthikeyan, N., E-mail: karthin10@gmail.com; Sivakumar, K.; Pachamuthu, M. P.

We focus on the application of powder diffraction data to get abinitio crystal structure determination of thiophene derived 1,4 DHP prepared by cyclocondensation method using solid catalyst. Crystal structure of the compound has been solved by direct-space approach on Monte Carlo search in parallel tempering mode using FOX program. Initial atomic coordinates were derived using Gaussian 09W quantum chemistry software in semi-empirical approach and Rietveld refinement was carried out using GSAS program. The crystal structure of the compound is stabilized by one N-H…O and three C-H…O hydrogen bonds. PIXEL lattice energy calculation was carried out to understand the physical naturemore » of intermolecular interactions in the crystal packing, on which the total lattice energy is contributed into Columbic, polarization, dispersion, and repulsion energies.« less

Novel Material Designed to Achieve Greater Tunability of Magnetic Dynamo Experiments

NASA Astrophysics Data System (ADS)

Casara, J. G.; Brown, E.

2013-12-01

We propose to use a novel material for dynamo experiments, creating suspensions of magnetic particles in liquid metals. These suspensions combine the conductive nature of liquid metals with the magnetic permeabilities of the particles, allowing much higher magnetic Reynolds numbers than previous liquid-metal experiments. Additionally, by adjusting the packing fraction φ of non-magnetic or magnetic particles in suspension, we can tune the viscosity and permeability respectively, thus achieving independent control of Reynolds and magnetic Reynolds numbers over a wide range of parameter space. We will report rheology measurements showing that liquid metal suspensions of 10μm diameter iron powders in a eutectic mixture of gallium and indium exhibit Newtonian viscosity with the expected increase in viscosity with φ up to φ = 0.22. Preliminary investigation into the magnetic properties of these suspensions has suggested that magnetic permeabilities are proportional to the packing fraction and inherent permeability of the suspended particles. These results confirm that the resulting Reynolds and magnetic Reynolds numbers will be highly tunable and straightforward to predict based on the proportions and properties of the suspension materials. The flow curve for suspensions of iron powder in eutectic gallium and indium exhibit Newtonian-like behavior for packing fractions φ below φ = 0.22. The viscosities of suspensions of iron powder in a eutectic mixture of gallium and indium follow a Krieger-Dougherty curve, providing more evidence that the material behaves in a Newtonian-like manner.

Molecular Packing of Amphiphilic Nanosheets Resolved by X-ray Scattering

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

Harutyunyan, Boris; Dannenhoffer, Adam; Kewalramani, Sumit

2016-12-29

Molecular packing in light harvesting 2D assemblies of photocatalytic materials is a critical factor for solar-to-fuel conversion efficiency. However, structure–function correlations have yet to be fully established. This is partly due to the difficulties in extracting the molecular arrangements from the complex 3D powder averaged diffraction patterns of 2D lattices, obtained via in situ wide-angle X-ray scattering. Here, we develop a scattering theory formalism and couple it with a simple geometrical model for the molecular shape of chromophore 9-methoxy-N-(sodium hexanoate)perylene-3,4-dicarboximide (MeO-PMI) used in our study. This generally applicable method fully reproduces the measured diffraction pattern including the asymmetric line shapesmore » for the Bragg reflections and yields the molecular packing arrangement within a 2D crystal structure with a remarkable degree of detail. We find an approximate edge-centered herringbone structure for the PMI fused aromatic rings and ordering of the carboxypentyl chains above and below the nanosheets. Such a packing arrangement differs from the more symmetric face-to-face orientation of the unsubstituted PMI rings. This structural difference is correlated to our measurement of the reduced catalytic performance of MeO-PMI nanosheets as compared to the mesoscopically similar unsubstituted PMI assemblies.« less

Microstructural characterization of random packings of cubic particles

PubMed Central

Malmir, Hessam; Sahimi, Muhammad; Tabar, M. Reza Rahimi

2016-01-01

Understanding the properties of random packings of solid objects is of critical importance to a wide variety of fundamental scientific and practical problems. The great majority of the previous works focused, however, on packings of spherical and sphere-like particles. We report the first detailed simulation and characterization of packings of non-overlapping cubic particles. Such packings arise in a variety of problems, ranging from biological materials, to colloids and fabrication of porous scaffolds using salt powders. In addition, packing of cubic salt crystals arise in various problems involving preservation of pavements, paintings, and historical monuments, mineral-fluid interactions, CO2 sequestration in rock, and intrusion of groundwater aquifers by saline water. Not much is known, however, about the structure and statistical descriptors of such packings. We have developed a version of the random sequential addition algorithm to generate such packings, and have computed a variety of microstructural descriptors, including the radial distribution function, two-point probability function, orientational correlation function, specific surface, and mean chord length, and have studied the effect of finite system size and porosity on such characteristics. The results indicate the existence of both spatial and orientational long-range order in the packing, which is more distinctive for higher packing densities. The maximum packing fraction is about 0.57. PMID:27725736

Noninvasive deep Raman detection with 2D correlation analysis

NASA Astrophysics Data System (ADS)

Kim, Hyung Min; Park, Hyo Sun; Cho, Youngho; Jin, Seung Min; Lee, Kang Taek; Jung, Young Mee; Suh, Yung Doug

2014-07-01

The detection of poisonous chemicals enclosed in daily necessaries is prerequisite essential for homeland security with the increasing threat of terrorism. For the detection of toxic chemicals, we combined a sensitive deep Raman spectroscopic method with 2D correlation analysis. We obtained the Raman spectra from concealed chemicals employing spatially offset Raman spectroscopy in which incident line-shaped light experiences multiple scatterings before being delivered to inner component and yielding deep Raman signal. Furthermore, we restored the pure Raman spectrum of each component using 2D correlation spectroscopic analysis with chemical inspection. Using this method, we could elucidate subsurface component under thick powder and packed contents in a bottle.

Synthesis and characterization of a new family of alkylammonium–chromium phosphates with worm-like morphology

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

Amghouz, Zakariae, E-mail: amghouz.uo@uniovi.es; Departamento de Química Orgánica e Inorgánica, Universidad de Oviedo-CINN, 33006 Oviedo; Espina, Aránzazu

A series of layered alkylammonium–chromium phosphates, formulated as [C{sub n}H{sub 2n+1}NH{sub 3}]Cr(OH)PO{sub 4} (n=2–6), has been synthesized under hydrothermal conditions. The interlayer spacing, increasing linearly with the increase of alkyl-chain length from 13.61 Å (n=2) to 21.20 Å (n=6), is occupied by a double sheet of packed amine molecules with a tilt angle of ca. 51° respect to the inorganic sheet. The powders are constituted by circular plates (diameter=0.5–3 µm, thickness=∼50 nm) with central holes when n=4–6, stacked in axial direction showing worm-like morphologies. The presence of holes, and some corrugated and zig-zag fashions observed on the edge of thinmore » circular plates are the most probable ways for the reduction of the steric tensions between organic and inorganic portions in these hybrid materials. The thermal and thermo-oxidative stability of selected compounds have been studied, including the determination of activation energy data for the decomposition processes. - Graphical abstract: A novel series of layered alkylammonium–chromium phosphates, [C{sub n}H{sub 2n+1}NH{sub 3}]Cr(OH)PO{sub 4} (n=2–6), was obtained and characterized. The interlayer spacing, increasing linearly with the increase of alkyl-chain length, is occupied by a double sheet of packed amine molecules. The powders are constituted by circular plates (diameter=0.5–3 µm, thickness=∼50 nm) with central holes when n=4–6, stacked in axial direction showing worm-like morphologies. - Highlights: • A series of alkylammonium–chromium phosphates has been obtained by the hydrothermal method. • The interlayer spacing increases linearly with the increase of alkyl-chain length. • The interlayer spacing is occupied by a double sheet of packed amine molecules. • The powders are constituted by stacked circular plates showing wormlike morphology. • Thermal behaviour depends on the atmosphere used and the intercalated amine.« less

Fabrication of carbonate apatite block based on internal dissolution-precipitation reaction of dicalcium phosphate and calcium carbonate.

PubMed

Daitou, Fumikazu; Maruta, Michito; Kawachi, Giichiro; Tsuru, Kanji; Matsuya, Shigeki; Terada, Yoshihiro; Ishikawa, Kunio

2010-05-01

In this study, we investigated a novel method for fabrication of carbonate apatite block without ionic movement between precursor and solution by using precursor that includes all constituent ions of carbonate apatite. A powder mixture prepared from dicalcium phosphate anhydrous and calcite at appropriate Ca/P ratios (1.5, 1.67, and 1.8) was used as starting material. For preparation of specimens, the slurry made from the powder mixture and distilled water was packed in a split stainless steel mold and heat - treated, ranging from 60 degrees C to 100 degrees C up to 48 hours at 100% humidity. It appeared that carbonate apatite could be obtained above 70 degrees C and monophasic carbonate apatite could be obtained from the powder mixture at Ca/P ratio of 1.67. Carbonate content of the specimen was about 5-7%. Diametral tensile strength of the carbonate apatite blocks slightly decreased with increasing treatment temperature. The decrease in diametral tensile strength is thought to be related to the crystal size of the carbonate apatite formed.

Microstructural characterization of random packings of cubic particles

DOE PAGES

Malmir, Hessam; Sahimi, Muhammad; Tabar, M. Reza Rahimi

2016-10-11

Understanding the properties of random packings of solid objects is of critical importance to a wide variety of fundamental scientific and practical problems. The great majority of the previous works focused, however, on packings of spherical and sphere-like particles. We report the first detailed simulation and characterization of packings of non-overlapping cubic particles. Such packings arise in a variety of problems, ranging from biological materials, to colloids and fabrication of porous scaffolds using salt powders. In addition, packing of cubic salt crystals arise in various problems involving preservation of pavements, paintings, and historical monuments, mineral-fluid interactions, CO 2 sequestration inmore » rock, and intrusion of groundwater aquifers by saline water. Not much is known, however, about the structure and statistical descriptors of such packings. We have developed a version of the random sequential addition algorithm to generate such packings, and have computed a variety of microstructural descriptors, including the radial distribution function, two-point probability function, orientational correlation function, specific surface, and mean chord length, and have studied the effect of finite system size and porosity on such characteristics. Here, the results indicate the existence of both spatial and orientational long-range order in the packing, which is more distinctive for higher packing densities.« less

Sustainable Blended Cements-Influences of Packing Density on Cement Paste Chemical Efficiency.

PubMed

Knop, Yaniv; Peled, Alva

2018-04-18

This paper addresses the development of blended cements with reduced clinker amount by partial replacement of the clinker with more environmentally-friendly material (e.g., limestone powders). This development can lead to more sustainable cements with reduced greenhouse gas emission and energy consumption during their production. The reduced clicker content was based on improved particle packing density and surface area of the cement powder by using three different limestone particle diameters: smaller (7 µm, 3 µm) or larger (70 µm, 53 µm) than the clinker particles, or having a similar size (23 µm). The effects of the different limestone particle sizes on the chemical reactivity of the blended cement were studied by X-ray diffraction (XRD), thermogravimetry and differential thermogravimetry (TG/DTG), loss on ignition (LOI), isothermal calorimetry, and the water demand for reaching normal consistency. It was found that by blending the original cement with limestone, the hydration process and the reactivity of the limestone itself were increased by the increased surface area of the limestone particles. However, the carbonation reaction was decreased with the increased packing density of the blended cement with limestone, having various sizes.

2. FOURTH FLOOR VIEW TO NORTHEAST, WITH I.J. STOKES DENTAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. FOURTH FLOOR VIEW TO NORTHEAST, WITH I.J. STOKES DENTAL POWDER FILLING MACHINE (CENTER) AND PACKING TABLE (LEFT CENTER) - Colgate & Company Jersey City Plant, G Block, 81-95 Greene Street, Jersey City, Hudson County, NJ

Cost and appropriateness of treating asthma with fixed-combination drugs in local health care units in Italy

PubMed Central

Ruggeri, Isabella; Bragato, Donatello; Colombo, Giorgio L; Valla, Emanuela; Di Matteo, Sergio

2012-01-01

Background Bronchial asthma is a chronic airways disease and is considered to be one of the major health problems in the Western world. During the last decade, a significant increase in the use of β2-agonists in combination with inhaled corticosteroids has been observed. The aim of this study was to assess the appropriateness of expenditure on these agents in an asthmatic population treated in a real practice setting. Methods This study used data for a resident population of 635,906 citizens in the integrated patient database (Banca Dati Assistito) of a local health care unit (Milano 2 Azienda Sanitaria Locale) in the Lombardy region over 3 years (2007–2009). The sample included 3787–4808 patients selected from all citizens aged ≥ 18 years entitled to social security benefits, having a prescription for a corticosteroid + β2-agonist combination, and an ATC code corresponding to R03AK, divided into three groups, ie, pressurized (spray) drugs, inhaled powders, and extrafine formulations. Patients with chronic obstructive lung disease were excluded. Indicators of appropriateness were 1–3 packs per year (underdosed, inappropriate), 4–12 packs per year (presumably appropriate), and ≥13 packs per year (overtreatment, inappropriate). Results The corticosteroid + β2-agonist combination per treated asthmatic patient increased from 37% in 2007 to 45% in 2009 for the total of prescribed antiasthma drugs, and 28%–32% of patients used the drugs in an appropriate manner (4–12 packs per years). The cost of inappropriately used packs increased combination drug expenditure by about 40%, leading to inefficient use of health care resources. This trend improved during the 3-year observation period. The mean annual cost per patient was higher for powders (€223.95) and sprays (€224.83) than for extrafine formulation (€142.71). Conclusion Based on this analysis, we suggest implementation of better health care planning and more appropriate prescription practices aimed at optimizing use of health care resources for the treatment of bronchial asthma. The results of our study should be extended to other regional/national reference local health care units, in order to define and compare average standard costs per pathology, and consolidated through the wide sample considered. PMID:23233808

Nutritional Composition of Australian Combat Ration Packs and Options for Improvement

DTIC Science & Technology

2013-10-01

cheese, scotch finger biscuit and sweetened condensed milk (Figure 9). High fat confectionery is the major contributor of vitamin A to CR1M menus...simultaneously assist in addressing the protein shortfall in all but one menu. 5.4.3 Dairy Skim milk powder is a minor component and not a major...The use of a moderate fat milk powder will also improve the stability of added vitamin A and should be considered as an alternative to the

Neurotoxin Mitigation

DTIC Science & Technology

2007-11-01

auto-sampler, and controller module , was used in this study. Chromatographic separation was performed on a Vydac C18 polymeric nanocolumn...as a dry powder at70C. Just before use, the dry powder was dissolved in 100% ethanol to a concentration of 13.3 mg/ml and diluted with saline to 15...for3min, and then eluted onto a C18 PepMap TM capillary column (15 cm3 75mm id, 3mm particle size both from LC Packings), using a flow rate of 200–300

Permeability model of sintered porous media: analysis and experiments

NASA Astrophysics Data System (ADS)

Flórez Mera, Juan Pablo; Chiamulera, Maria E.; Mantelli, Marcia B. H.

2017-11-01

In this paper, the permeability of porous media fabricated from copper powder sintering process was modeled and measured, aiming the use of the porosity as input parameter for the prediction of the permeability of sintering porous media. An expression relating the powder particle mean diameter with the permeability was obtained, based on an elementary porous media cell, which is physically represented by a duct formed by the arrangement of spherical particles forming a simple or orthorhombic packing. A circular duct with variable section was used to model the fluid flow within the porous media, where the concept of the hydraulic diameter was applied. Thus, the porous is modeled as a converging-diverging duct. The electrical circuit analogy was employed to determine two hydraulic resistances of the cell: based on the Navier-Stokes equation and on the Darcýs law. The hydraulic resistances are compared between themselves and an expression to determine the permeability as function of average particle diameter is obtained. The atomized copper powder was sifted to reduce the size dispersion of the particles. The porosities and permeabilities of sintered media fabricated from powders with particle mean diameters ranging from 20 to 200 microns were measured, by means of the image analysis method and using an experimental apparatus. The permeability data of a porous media, made of copper powder and saturated with distilled water, was used to compare with the permeability model. Permeability literature models, which considers that powder particles have the same diameter and include porosity data as input parameter, were compared with the present model and experimental data. This comparison showed to be quite good.

Thermal conductivity model for powdered materials under vacuum based on experimental studies

NASA Astrophysics Data System (ADS)

Sakatani, N.; Ogawa, K.; Iijima, Y.; Arakawa, M.; Honda, R.; Tanaka, S.

2017-01-01

The thermal conductivity of powdered media is characteristically very low in vacuum, and is effectively dependent on many parameters of their constituent particles and packing structure. Understanding of the heat transfer mechanism within powder layers in vacuum and theoretical modeling of their thermal conductivity are of great importance for several scientific and engineering problems. In this paper, we report the results of systematic thermal conductivity measurements of powdered media of varied particle size, porosity, and temperature under vacuum using glass beads as a model material. Based on the obtained experimental data, we investigated the heat transfer mechanism in powdered media in detail, and constructed a new theoretical thermal conductivity model for the vacuum condition. This model enables an absolute thermal conductivity to be calculated for a powder with the input of a set of powder parameters including particle size, porosity, temperature, and compressional stress or gravity, and vice versa. Our model is expected to be a competent tool for several scientific and engineering fields of study related to powders, such as the thermal infrared observation of air-less planetary bodies, thermal evolution of planetesimals, and performance of thermal insulators and heat storage powders.

Direct-current arc and alternating-current spark emission spectrographic field methods for the semiquantitative analysis of geologic materials

USGS Publications Warehouse

Grimes, D.J.; Marranzino, A.P.

1968-01-01

Two spectrographic methods are used in mobile field laboratories of the U. S. Geological Survey. In the direct-current arc method, the ground sample is mixed with graphite powder, packed into an electrode crater, and burned to completion. Thirty elements are determined. In the spark method, the sample, ground to pass a 150-mesh screen, is digested in hydrofluoric acid followed by evaporation to dryness and dissolution in aqua regia. The solution is fed into the spark gap by means of a rotating-disk electrode arrangement and is excited with an alternating-current spark discharge. Fourteen elements are determined. In both techniques, light is recorded on Spectrum Analysis No. 1, 35-millimeter film, and the spectra are compared visually with those of standard films.

Electrical conductivity of metal powders under pressure

NASA Astrophysics Data System (ADS)

Montes, J. M.; Cuevas, F. G.; Cintas, J.; Urban, P.

2011-12-01

A model for calculating the electrical conductivity of a compressed powder mass consisting of oxide-coated metal particles has been derived. A theoretical tool previously developed by the authors, the so-called `equivalent simple cubic system', was used in the model deduction. This tool is based on relating the actual powder system to an equivalent one consisting of deforming spheres packed in a simple cubic lattice, which is much easier to examine. The proposed model relates the effective electrical conductivity of the powder mass under compression to its level of porosity. Other physically measurable parameters in the model are the conductivities of the metal and oxide constituting the powder particles, their radii, the mean thickness of the oxide layer and the tap porosity of the powder. Two additional parameters controlling the effect of the descaling of the particle oxide layer were empirically introduced. The proposed model was experimentally verified by measurements of the electrical conductivity of aluminium, bronze, iron, nickel and titanium powders under pressure. The consistency between theoretical predictions and experimental results was reasonably good in all cases.

Reducing metal alloy powder costs for use in powder bed fusion additive manufacturing: Improving the economics for production

NASA Astrophysics Data System (ADS)

Medina, Fransisco

Titanium and its associated alloys have been used in industry for over 50 years and have become more popular in the recent decades. Titanium has been most successful in areas where the high strength to weight ratio provides an advantage over aluminum and steels. Other advantages of titanium include biocompatibility and corrosion resistance. Electron Beam Melting (EBM) is an additive manufacturing (AM) technology that has been successfully applied in the manufacturing of titanium components for the aerospace and medical industry with equivalent or better mechanical properties as parts fabricated via more traditional casting and machining methods. As the demand for titanium powder continues to increase, the price also increases. Titanium spheroidized powder from different vendors has a price range from 260/kg-450/kg, other spheroidized alloys such as Niobium can cost as high as $1,200/kg. Alternative titanium powders produced from methods such as the Titanium Hydride-Dehydride (HDH) process and the Armstrong Commercially Pure Titanium (CPTi) process can be fabricated at a fraction of the cost of powders fabricated via gas atomization. The alternative powders can be spheroidized and blended. Current sectors in additive manufacturing such as the medical industry are concerned that there will not be enough spherical powder for production and are seeking other powder options. It is believed the EBM technology can use a blend of spherical and angular powder to build fully dense parts with equal mechanical properties to those produced using traditional powders. Some of the challenges with angular and irregular powders are overcoming the poor flow characteristics and the attainment of the same or better packing densities as spherical powders. The goal of this research is to demonstrate the feasibility of utilizing alternative and lower cost powders in the EBM process. As a result, reducing the cost of the raw material to reduce the overall cost of the product produced with AM. Alternative powders can be made by blending or re-spheroidizing HDH and CPTi powders. Machine modifications were performed to allow the testing and manufacturing with these low cost alternative powders. A comparison was made between alternative powders and gas atomized powders. Powders were compared in terms of morphology and at the microstructural level. Flowability of different powder blends was also measured. Finally, a comparison of parts fabricated from the multiple powder blends and gas atomized powder was made. It has been demonstrated that powder blending can produce fully dense parts in the Arcam system by utilizing the double melt technique or HIPing the built pars. The double melt technique increased the density of the sample part and modified the microstructure into finer martensitic grains. The HIP process can make a part fully dense regardless of what percentage of HDH powder blending is used. The HIP process yielded the same microstructure, regardless of the grain structure it started with. This research allows for the reduction of costs using titanium powders in the EBM system, but can also be implemented with more costly elements and alloys using other metal AM technologies. This includes niobium, tantalum, and nickel-based superalloys for use in various industries.

Chemiluminescence measurements on irradiated garlic powder by the single photon counting technique

NASA Astrophysics Data System (ADS)

Narvaiz, P.

1995-02-01

The feasibility of identifying irradiated garlic powder measuring chemiluminescence by liquid scintillation spectrometry was studied. Samples packed in 100 μm thick polyethylene bags were irradiated in a 60Co semi-industrial facility, with doses of 10 and 30 kGy. Control and irradiated samples were stored at 20 ± 4°C and 70 ± 10% RH in darkness for 2 years. Assays were performed to establish the best sample concentration and pH of the buffer solution in which garlic powder was to be suspended for its measurement. The water content of garlic samples was also analyzed throughout storage time, as it related to the stability of the species causing luminescence. Chemiluminescence values diminished in every sample over storage time following an exponential pattern. Irradiated samples showed values significantly higher than those of the control samples, according to the radiation dose, throughout the storage period. This does not necessarily imply that the identification of the irradiated samples would be certain, since values of control samples coming from different origins have been found to fluctuate within a rather wide range. Nonetheless, in principle, the method looks promising for the measurement of chemiluminescence in irradiated samples

High temperature oxidation in boiler environment of chromized steel

NASA Astrophysics Data System (ADS)

Alia, F. F.; Kurniawan, T.; Asmara, Y. P.; Ani, M. H. B.; Nandiyanto, A. B. D.

2017-10-01

The demand for increasing efficiency has led to the development and construction of higher operating temperature power plant. This condition may lead to more severe thickness losses in boiler tubes due to excessive corrosion process. Hence, the research to improve the corrosion resistance of the current operated material is needed so that it can be applied for higher temperature application. In this research, the effect of chromizing process on the oxidation behaviour of T91 steel was investigated under steam condition. In order to deposit chromium, mixture of chromium (Cr) powder as master alloy, halide salt (NH4Cl) powder as activator and alumina (Al2O3) powder as inert filler were inserted into alumina retort together with the steel sample and heated inside furnace at 1050°C for ten hours under argon gas environment. Furthermore, for the oxidation process, steels were exposed at 700°C at different oxidation time (6h-24h) under steam condition. From FESEM/EDX analysis, it was found that oxidation rate of pack cemented steel was lower than the un-packed steel. These results show that Cr from chromizing process was able to become reservoir for the formation of Cr2O3 in high temperature steam oxidation, and its existence can be used for a longer oxidation time.

Novel three-dimensional dandelion-like TiO{sub 2} structure with high photocatalytic activity

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

Bai Xuelian; Xie Bin; Pan Nan

2008-03-15

Pure rutile phase crystalline TiO{sub 2} powder with novel 3D dandelion-like structure was synthesized by using a facile hydrothermal method with TiCl{sub 3} as the main starting material. In such a 3D structure, the nanometer-scale construction elements aggregate together and form a micrometer-scale artificial unit. The typical 3D dandelion structure has an average diameter of 1.5-2 {mu}m and is packed radially by nanorods with [001] preference growth direction. Each individual nanorod is hundreds of nanometers in length, and tens of nanometers in diameter. The obtained 3D dandelion-like TiO{sub 2} powder has a high photocatalytic activity, which is equivalent to thatmore » of the commercial available P25 titania powder. Mechanisms of the formation of the dandelion-like structure were also discussed. A different oxidation process of Ti(III) to Ti(IV) during hydrothermal was suggested. - Graphical abstract: Rutile-phase TiO{sub 2} powders with novel 3D dandelion-like structures were synthesized. This kind of 3D artificial hierarchical titania structure has the advantage of reserving the novel nanometer-scale properties while providing us the easiness of storing and handling as we routinely enjoyed for the micrometer-scale materials. A different oxidation process of Ti(III) to Ti(IV) during hydrothermal process was suggested.« less

Random close packing of polydisperse jammed emulsions

NASA Astrophysics Data System (ADS)

Brujic, Jasna

2010-03-01

Packing problems are everywhere, ranging from oil extraction through porous rocks to grain storage in silos and the compaction of pharmaceutical powders into tablets. At a given density, particulate systems pack into a mechanically stable and amorphous jammed state. Theoretical frameworks have proposed a connection between this jammed state and the glass transition, a thermodynamics of jamming, as well as geometric modeling of random packings. Nevertheless, a simple underlying mechanism for the random assembly of athermal particles, analogous to crystalline ordering, remains unknown. Here we use 3D measurements of polydisperse packings of emulsion droplets to build a simple statistical model in which the complexity of the global packing is distilled into a local stochastic process. From the perspective of a single particle the packing problem is reduced to the random formation of nearest neighbors, followed by a choice of contacts among them. The two key parameters in the model, the available space around a particle and the ratio of contacts to neighbors, are directly obtained from experiments. Remarkably, we demonstrate that this ``granocentric'' view captures the properties of the polydisperse emulsion packing, ranging from the microscopic distributions of nearest neighbors and contacts to local density fluctuations and all the way to the global packing density. Further applications to monodisperse and bidisperse systems quantitatively agree with previously measured trends in global density. This model therefore reveals a general principle of organization for random packing and lays the foundations for a theory of jammed matter.

Depth of penetration of a 785nm wavelength laser in food powders

NASA Astrophysics Data System (ADS)

Chao, Kuanglin; Dhakal, Sagar; Qin, Jianwei; Kim, Moon S.; Peng, Yankun; Schmidt, Walter F.

2015-05-01

Raman spectroscopy is a useful, rapid, and non-destructive method for both qualitative and quantitative evaluation of chemical composition. However it is important to measure the depth of penetration of the laser light to ensure that chemical particles at the very bottom of a sample volume is detected by Raman system. The aim of this study was to investigate the penetration depth of a 785nm laser (maximum power output 400mw) into three different food powders, namely dry milk powder, corn starch, and wheat flour. The food powders were layered in 5 depths between 1 and 5 mm overtop a Petri dish packed with melamine. Melamine was used as the subsurface reference material for measurement because melamine exhibits known and identifiable Raman spectral peaks. Analysis of the sample spectra for characteristics of melamine and characteristics of milk, starch and flour allowed determination of the effective penetration depth of the laser light in the samples. Three laser intensities (100, 200 and 300mw) were used to study the effect of laser intensity to depth of penetration. It was observed that 785nm laser source was able to easily penetrate through every point in all three food samples types at 1mm depth. However, the number of points that the laser could penetrate decreased with increasing depth of the food powder. ANOVA test was carried out to study the significant effect of laser intensity to depth of penetration. It was observed that laser intensity significantly influences the depth of penetration. The outcome of this study will be used in our next phase of study to detect different chemical contaminants in food powders and develop quantitative analysis models for detection of chemical contaminants.

49 CFR 171.8 - Definitions and abbreviations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... definitions relating to radioactive materials. Rail car means a car designed to carry freight or non-passenger... Materials Safety Administration. Aerosol means any non-refillable receptacle containing a gas compressed... Division 6.1 Packing Group III material) liquid, paste, or powder and fitted with a self-closing release...

49 CFR 171.8 - Definitions and abbreviations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... definitions relating to radioactive materials. Rail car means a car designed to carry freight or non-passenger... Materials Safety Administration. Aerosol means any non-refillable receptacle containing a gas compressed... Division 6.1 Packing Group III material) liquid, paste, or powder and fitted with a self-closing release...

49 CFR 171.8 - Definitions and abbreviations.

Code of Federal Regulations, 2014 CFR

2014-10-01

... definitions relating to radioactive materials. Rail car means a car designed to carry freight or non-passenger... Materials Safety Administration. Aerosol means any non-refillable receptacle containing a gas compressed... Division 6.1 Packing Group III material) liquid, paste, or powder and fitted with a self-closing release...

49 CFR 171.8 - Definitions and abbreviations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... definitions relating to radioactive materials. Rail car means a car designed to carry freight or non-passenger... Materials Safety Administration. Aerosol means any non-refillable receptacle containing a gas compressed... Division 6.1 Packing Group III material) liquid, paste, or powder and fitted with a self-closing release...

Improved consolidation of silicon carbide

NASA Technical Reports Server (NTRS)

Freedman, M. R.; Millard, M. L.

1986-01-01

Alpha silicon carbide powder was consolidated by both dry and wet methods. Dry pressing in a double acting steel die yielded sintered test bars with an average flexural strength of 235.6 MPa with a critical flaw size of approximately 100 micro m. An aqueous slurry pressing technique produced sintered test bars with an average flexural strength of 440.8 MPa with a critical flaw size of approximately 25 micro m. Image analysis revealed a reduction in both pore area and pore size distribution in the slurry pressed sintered test bars. The improvements in the slurry pressed material properties are discussed in terms of reduced agglomeration and improved particle packing during consolidation.

Photocatalytic degradation of congo red using copper substituted cobalt ferrite

NASA Astrophysics Data System (ADS)

Kirankumar, V. S.; Hardik, B.; Sumathi, S.

2017-11-01

Co1-xCuxFe2O4 nanoparticles with x = 0 and 0.5 were synthesized through the combustion method. The as-made materials are face centered-cubic close-packed spinel structures. The characterization techniques such as powder XRD, FTIR, UV-DRS and SEM studies collectively verified that the formed products are cobalt ferrite and copper substituted cobalt ferrite nanoparticles. In addition, the mean crystalline size, lattice parameter and band gap energy of nanoparticles are calculated. The photocatalytic activity of the obtained Co1-xCuxFe2O4 spinel nanoparticles is evaluated by monitoring the degradation of congo red under visible light irradiation.

Effects of glass scraps powder and glass fiber on mechanical properties of polyester composites

NASA Astrophysics Data System (ADS)

Sonsakul, K.; Boongsood, W.

2017-11-01

One concern in bus manufacturing is the high cost of glass fiber reinforced in polyester composites parts. The composites of glass fiber and polyester are low elongation and high strength, and glass scraps powder displays high hardness and good chemical compatibility with the polymer matrix and glass fiber. This research aimed to study the effects of glass scraps powder and glass fiber on mechanical performance of polyester composites. Glass fiber was randomly oriented fiber and used as new. Glass scraps were obtained from a bus factory and crushed to powder sizes of 120 and 240 μm by a ball mill. Polyester composites were prepared using Vacuum Infusion Process (VIP).Polyester reinforced with 3 layers of glass fiber was an initial condition. Then, one layer of glass fiber was replaced with glass scraps powder. Flexural strength, tensile strength, impact strength and hardness of the polyester composites were determined. Hardness was increased with a combination of smaller size and higher volume of glass scraps powder. Pictures of specimens obtained by using scanning electron microscope (SEM) confirmed that the powder of glass scraps packed in the layers of glass fiber in polyester composites.

The Morphology of Titanium Dioxide Aerogels

NASA Astrophysics Data System (ADS)

Zhu, Zhu

The morphology of titanium dioxide TiO _2 aerogels has been characterized by four major techniques. This work will discuss these complementary techniques such as nitrogen adsorption, X-ray powder diffraction (XRD), electron microscopies (EM- TEM, SEM), and small angle neutron scattering (SANS). The results of these characterizations have shown that the morphology of titanium dioxide TiO_2 aerogels can be characterized in terms of two length scales: 5 nm diameter, crystalline nanoparticles of anatase closely packed into mesoaggregates about 50 nm in size. The mesoaggregates are, in turn, packed into a loosely linked structure with an overall porosity of 80%.

Effect of nano-packing on preservation quality of fresh strawberry (Fragaria ananassa Duch. cv Fengxiang) during storage at 4 degrees C.

PubMed

Yang, F M; Li, H M; Li, F; Xin, Z H; Zhao, L Y; Zheng, Y H; Hu, Q H

2010-04-01

A novel nano-packing material with lower relative humidity, oxygen transmission rate and high longitudinal strength was synthesized by blending polyethylene with nano-powder (nano-Ag, kaolin, anatase TiO(2), rutile TiO(2)), and its effect on preservation quality of strawberry fruits (Fragaria ananassa Duch. cv Fengxiang) was investigated during storage at 4 degrees C. Results showed that nano-packaging was able to maintain the sensory, physicochemical, and physiological quality of strawberry fruits at a higher level compared with the normal packing (polyethylene bags). After a 12-d storage, decreases in the contents of total soluble solids, titratable acidity, and ascorbic acid of nano-packing were significantly inhibited. Meanwhile, decay rate, anthocyanin, and malondialdehyde contents were decreased to 16.7%, 26.3 mg/100g, 66.3 micromol/g for nano-packing and 26.8%, 31.9 mg/100g, 75.4 micromol/g for normal packing; polyphenoloxidase (PPO) and pyrogallol peroxidase (POD) activities were significantly lower in nano-packing than the control. These data indicated that the nano-packaging might provide an attractive alternative to improve preservation quality of the strawberry fruits during extended storage. Nano-packing exhibited identified quality benefits applicable to the preservation of fresh strawberry. Furthermore, nano-packing has the advantages of simple processing and feasibility to be industrialized in contrast with other storages. Thus, the utilization of nano-packing will likely assist commercial producers and retailers in extending the shelf life of products over a broader range in the future.

The thermal stability and catalytic application of manganese oxide-zirconium oxide powders

NASA Astrophysics Data System (ADS)

Zhao, Qiang

MnOx-ZrO2 mixed oxide is an active catalyst for combustion, oxidation, and oxygen storage applications. MnOx-ZrO 2 mixture also has large reversible adsorption capability for NO x, which makes it a promising candidate for NOx abatement in automobile emission control. However, MnOx-ZrO 2 mixed oxide has not been used extensively because the processing and the thermal stability of resulting powders have not been studied systematically. It is critical to have thermally stable catalytic material because the application temperature can reach as high as 1000°C during service. In this study, we focused on improving the thermal stability of oxide powders, such as MnO x, ZrO2, and MnOx-ZrO2, by controlling the processing methods and parameters. For pure MnOx made from the precipitation method using Mn(NO3)2 aqueous solution and ammonium hydroxide, we found that lower concentration of Mn(NO3) 2 solution and larger amount of ammonium hydroxide resulted in higher surface area powders. For pure ZrO2, we found curing hydrous zirconia in the mother liquid produced ZrO2 powders with larger pore volume and pore size. The specific surface area was also significantly enhanced by curing for the synthesized powders before calcination or after low temperature calcinations, and this improvement could be preserved to high temperatures if SiO2 was doped in ZrO2. A Monte Carlo simulation model examining the effect of primary particle packing on the specific surface area was used to explain the curing result. MnOx-ZrO2 mixtures had higher surface area than the single component oxide at 500 and 700°C because composite powders sintered less. The sintering behavior of composite powders at 900°C was opposite to that at 500°C and the specific surface area of MnOx-ZrO2 decreased drastically at 900°C. Curing ZrO2 first or using La dopant could significantly enhance the specific surface area of MnOx-ZrO2 at 900°C. Through the tests of the redox property and NO storage capability we found a close relationship between the enhanced thermal stability and better catalytic performance.

Mechanics of Granular Materials (MGM)

NASA Technical Reports Server (NTRS)

2000-01-01

The packing of particles can change radically during cyclic loading such as in an earthquake or when shaking a container to compact a powder. A large hole (1) is maintained by the particles sticking to each other. A small, counterclockwise strain (2) collapses the hole, and another large strain (3) forms more new holes which collapse when the strain reverses (4). Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (after T.L. Youd, Packing Changes and Liquefaction Susceptibility, Journal of the Geotechnical Engieering Division, 103: GT8,918-922, 1977)(Credit: NASA/Marshall Space Flight Center.)(Credit: University of Colorado at Boulder).

Microgravity

NASA Image and Video Library

2000-07-01

The packing of particles can change radically during cyclic loading such as in an earthquake or when shaking a container to compact a powder. A large hole (1) is maintained by the particles sticking to each other. A small, counterclockwise strain (2) collapses the hole, and another large strain (3) forms more new holes which collapse when the strain reverses (4). Sand and soil grains have faces that can cause friction as they roll and slide against each other, or even cause sticking and form small voids between grains. This complex behavior can cause soil to behave like a liquid under certain conditions such as earthquakes or when powders are handled in industrial processes. MGM experiments aboard the Space Shuttle use the microgravity of space to simulate this behavior under conditions that carnot be achieved in laboratory tests on Earth. MGM is shedding light on the behavior of fine-grain materials under low effective stresses. Applications include earthquake engineering, granular flow technologies (such as powder feed systems for pharmaceuticals and fertilizers), and terrestrial and planetary geology. Nine MGM specimens have flown on two Space Shuttle flights. Another three are scheduled to fly on STS-107. The principal investigator is Stein Sture of the University of Colorado at Boulder. (after T.L. Youd, Packing Changes and Liquefaction Susceptibility, Journal of the Geotechnical Engieering Division, 103: GT8,918-922, 1977)(Credit: NASA/Marshall Space Flight Center.)(Credit: University of Colorado at Boulder).

Crystal structure of paliperidone palmitate (INVEGA SUSTENNA®), C39H57FN4O4

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

Kaduk, James A.; Dmitrienko, Artem O.; Gindhart, Amy M.

2017-08-29

The crystal structure of paliperidone palmitate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Paliperidone palmitate crystallizes in space groupP2 1/c(#14) witha= 34.415 40(35),b= 10.093 49(7),c= 10.904 92(9) Å,β= 94.3917(9)°,V= 3776.94(6) Å 3, andZ= 4. The conformation of the paliperidone fragment differs from that of the parent compound. The palmitate chain exhibits a slight twist close to the ester group. Several C–H•••O hydrogen bonds contribute to the crystal packing, which is dominated by van der Waals interactions. The powder pattern is included in the Powder Diffraction File™ as entry 00-066-1614.

Encapsulation of CO2 into amorphous alpha-cyclodextrin powder at different moisture contents - Part 2: Characterization of complexed powders and determination of crystalline structure.

PubMed

Ho, Thao M; Howes, Tony; Jack, Kevin S; Bhandari, Bhesh R

2016-09-01

This study aims to characterize CO2-α-cyclodextrin (α-CD) inclusion complexes produced from amorphous α-CD powder at moisture contents (MC) close to or higher than the critical level of crystallization (e.g. 13, 15 and 17% MC on wet basis, w.b.) at 0.4 and 1.6MPa pressure for 72h. The results of (13)C NMR, SEM, DSC and X-ray analyses showed that these MC levels were high enough to induce crystallization of CO2-α-CD complexed powders during encapsulation, by which amount of CO2 encapsulated by amorphous α-CD powder was significantly increased. The formation of inclusion complexes were well confirmed by results of FTIR and (13)C NMR analyses through an appearance of a peak associated with CO2 on the FTIR (2334cm(-1)) and NMR (125.3ppm) spectra. Determination of crystal packing patterns of CO2-α-CD complexed powders showed that during crystallization, α-CD molecules were arranged in cage-type structure in which CO2 molecules were entrapped in isolated cavities. Copyright © 2016 Elsevier Ltd. All rights reserved.

Printability of calcium phosphate: calcium sulfate powders for the application of tissue engineered bone scaffolds using the 3D printing technique.

PubMed

Zhou, Zuoxin; Buchanan, Fraser; Mitchell, Christina; Dunne, Nicholas

2014-05-01

In this study, calcium phosphate (CaP) powders were blended with a three-dimensional printing (3DP) calcium sulfate (CaSO4)-based powder and the resulting composite powders were printed with a water-based binder using the 3DP technology. Application of a water-based binder ensured the manufacture of CaP:CaSO4 constructs on a reliable and repeatable basis, without long term damage of the printhead. Printability of CaP:CaSO4 powders was quantitatively assessed by investigating the key 3DP process parameters, i.e. in-process powder bed packing, drop penetration behavior and the quality of printed solid constructs. Effects of particle size, CaP:CaSO4 ratio and CaP powder type on the 3DP process were considered. The drop penetration technique was used to reliably identify powder formulations that could be potentially used for the application of tissue engineered bone scaffolds using the 3DP technique. Significant improvements (p<0.05) in the 3DP process parameters were found for CaP (30-110 μm):CaSO4 powders compared to CaP (<20 μm):CaSO4 powders. Higher compressive strength was obtained for the powders with the higher CaP:CaSO4 ratio. Hydroxyapatite (HA):CaSO4 powders showed better results than beta-tricalcium phosphate (β-TCP):CaSO4 powders. Solid and porous constructs were manufactured using the 3DP technique from the optimized CaP:CaSO4 powder formulations. High-quality printed constructs were manufactured, which exhibited appropriate green compressive strength and a high level of printing accuracy. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis of Biodiesel in Batch and Packed-Bed Reactors Using Powdered and Granular Sugar Catalyst

NASA Astrophysics Data System (ADS)

Janaun, J.; Lim, P. M.; Balan, W. S.; Yaser, A. Z.; Chong, K. P.

2017-06-01

Increasing world production of palm oil warrants effective utilization of its waste. In particular, conversion of waste cooking oil into biodiesel has obtained global interest because of renewable energy need and reduction of CO2 emission. In this study, oleic acid used as a model compound for waste cooking oil conversion using esterification reaction catalysed by sugar catalyst (SC) in powdered (P-SC) and granular (G-SC) forms. The catalysts were synthesized via incomplete carbonization of D-glucose followed by functionalization with concentrated sulphuric acid. Catalysts characterizations were done for their physical and chemical properties using modern tools. Batch and packed-bed reactor systems were used to evaluate the reactivity of the catalysts. The results showed that G-SC had slightly higher total acidity and more porous than P-SC. The experimental conditions for batch reaction were temperature of 60°C, molar ratio of 1:20 (Oleic Acid:Methanol) and 2 wt. catalyst with respect to oleic acid. The results showed the maximum oleic acid conversion using G-SC and P-SC were 52 and 48, respectively. Whereas, the continuous reaction with varying feed flow rate as a function of retention time was studied by using 3 g of P-SC in 60 °C and 1:20 molar ratio in a packed-bed reactor. The results showed that a longer retention time which was 6.48 min and feed flow rate 1.38 ml/min, achieved higher average conversion of 9.9 and decreased with further increasing flow rate. G-SC showed a better average conversion of 10.8 at lowest feed flow rate of 1.38 ml/min in continuous reaction experiments. In a broader perspective, large scale continuous biodiesel production is feasible using granular over powdered catalyst mainly due to it lower pressure drop.

Effect of drying, storage temperature and air exposure on astaxanthin stability from Haematococcus pluvialis.

PubMed

Ahmed, Faruq; Li, Yan; Fanning, Kent; Netzel, Michael; Schenk, Peer M

2015-08-01

Astaxanthin is a powerful antioxidant with various health benefits such as prevention of age-related macular degeneration and improvement of the immune system, liver and heart function. To improve the post-harvesting stability of astaxanthin used in food, feed and nutraceutical industries, the biomass of the high astaxanthin producing alga Haematococcus pluvialis was dried by spray- or freeze-drying and under vacuum or air at -20°C to 37°C for 20weeks. Freeze-drying led to 41% higher astaxanthin recovery compared to commonly-used spray-drying. Low storage temperature (-20°C, 4°C) and vacuum-packing also showed higher astaxanthin stability with as little as 12.3±3.1% degradation during 20weeks of storage. Cost-benefit analysis showed that freeze-drying followed by vacuum-packed storage at -20°C can generate AUD$600 higher profit compared to spray-drying from 100kgH. pluvialis powder. Therefore, freeze-drying can be suggested as a mild and more profitable method for ensuring longer shelf life of astaxanthin from H. pluvialis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Low-cost synthesis and physical characterization of thieno[3,4-c]pyrrole-4,6-dione-based polymers.

PubMed

Berrouard, Philippe; Dufresne, Stéphane; Pron, Agnieszka; Veilleux, Justine; Leclerc, Mario

2012-09-21

The improved synthesis of thieno[3,4-c]pyrrole-4,6-dione (TPD) monomers, including Gewald thiophene ring formation, a Sandmeyer-type reaction, and neat condensation with an amine, is presented. This protocol enables faster, cheaper, and more efficient preparation of TPD units in comparison to traditional methods. Furthermore, a series of TPD homo- and pseudohomopolymers bearing various alkyl chains was synthesized via a direct heteroarylation polymerization (DHAP) procedure. UV-visible absorption and powder X-ray diffraction measurements revealed the relationship between the ratio of branched to linear alkyl chains and the optoelectronic properties of the polymers as well as their packing in the solid state.

The antifriction behaviours of ?

NASA Astrophysics Data System (ADS)

Yan, Feng-yuan; Xue, Qun-ji

1997-03-01

In this paper, the antifriction behaviours of 0022-3727/30/5/010/img2 (3:1) molecules and their crystal powder were evaluated by different methods. It was found that the 0022-3727/30/5/010/img2 crystal powder possessed hexagonal close packed (hcp) crystal structure with a = 10.1 Å and c = 16.55 Å, and a transformation of crystal structure from hcp to face centred cubic (fcc) occurred easily during friction (burnishing). It was confirmed that two kinds of process, breakage of 0022-3727/30/5/010/img2 powder coagulated by nanoscale single crystals and rearrangement of the molecules along the friction direction, had occurred under the friction force. The extreme pressure (EP) performance of 0022-3727/30/5/010/img2 as an additive in paraffin liquid was investigated on an SRV oscillating wear machine. It was found that the extreme pressure load (EP value) of paraffin liquid was increased by dispersion of 0022-3727/30/5/010/img2 powder, accompanied by a slight improvement in the antifriction behaviour. it was confirmed that the improvement in EP value and antifriction behaviour of oil was dependent on the crystal structure of 0022-3727/30/5/010/img2 powder, but independent of the spherical molecular structure of 0022-3727/30/5/010/img8 or 0022-3727/30/5/010/img9. The burnishing experimental results also proved that the antifriction behaviour was determined by the crystal structure and had no relation to the molecular structure. It was also found that fullerenes possessed some physical properties similar to those of graphite. Since the formation of compact fullerenes with high shear strength during friction can be effectively prevented by some other lubricants, it is suggested that fullerenes should be mixed with other lubricants for tribological application.

Processing of laser formed SiC powder

NASA Technical Reports Server (NTRS)

Haggerty, J. S.; Bowen, H. K.

1987-01-01

Processing research was undertaken to demonstrate that superior SiC characteristics could be achieved through the use of ideal constituent powders and careful post-synthesis processing steps. Initial research developed the means to produce approximately 1000 A uniform diameter, nonagglomerated, spherical, high purity SiC powders. Accomplishing this goal required major revision of the particle formation and growth model from one based on classical nucleation and growth to one based on collision and coalescence of Si particles followed by their carburization. Dispersions based on pure organic solvents as well as steric stabilization were investigated. Test parts were made by the colloidal pressing technique; both liquid filtration and consolidation (rearrangement) stages were modeled. Green densities corresponding to a random close packed structure were achieved. After drying, parts were densified at temperatures ranging from 1800 to 2100 C. This research program accomplished all of its major objectives. Superior microstructures and properties were attained by using powders having ideal characteristics and special post-synthesis processing procedures.

Confined disordered strictly jammed binary sphere packings

NASA Astrophysics Data System (ADS)

Chen, D.; Torquato, S.

2015-12-01

Disordered jammed packings under confinement have received considerably less attention than their bulk counterparts and yet arise in a variety of practical situations. In this work, we study binary sphere packings that are confined between two parallel hard planes and generalize the Torquato-Jiao (TJ) sequential linear programming algorithm [Phys. Rev. E 82, 061302 (2010), 10.1103/PhysRevE.82.061302] to obtain putative maximally random jammed (MRJ) packings that are exactly isostatic with high fidelity over a large range of plane separation distances H , small to large sphere radius ratio α , and small sphere relative concentration x . We find that packing characteristics can be substantially different from their bulk analogs, which is due to what we term "confinement frustration." Rattlers in confined packings are generally more prevalent than those in their bulk counterparts. We observe that packing fraction, rattler fraction, and degree of disorder of MRJ packings generally increase with H , though exceptions exist. Discontinuities in the packing characteristics as H varies in the vicinity of certain values of H are due to associated discontinuous transitions between different jammed states. When the plane separation distance is on the order of two large-sphere diameters or less, the packings exhibit salient two-dimensional features; when the plane separation distance exceeds about 30 large-sphere diameters, the packings approach three-dimensional bulk packings. As the size contrast increases (as α decreases), the rattler fraction dramatically increases due to what we call "size-disparity" frustration. We find that at intermediate α and when x is about 0.5 (50-50 mixture), the disorder of packings is maximized, as measured by an order metric ψ that is based on the number density fluctuations in the direction perpendicular to the hard walls. We also apply the local volume-fraction variance στ2(R ) to characterize confined packings and find that these packings possess essentially the same level of hyperuniformity as their bulk counterparts. Our findings are generally relevant to confined packings that arise in biology (e.g., structural color in birds and insects) and may have implications for the creation of high-density powders and improved battery designs.

Oxidation-resisting technology of W-Re thermocouples and their industrial applications

NASA Astrophysics Data System (ADS)

Wang, K.; Dai, M.; Dong, J.; Wang, L.; Wang, T.

2013-09-01

We use DSC/TG, SEM and EPMA approaches to investigate the high temperature oxidation behaviors of the Type C W-Re thermocouple wires and W-Re powders which the wires were made from. To solve the oxidization of W-Re thermocouples the chemical method, other than the commonly used physical method, i.e. vacuum-pumping method, was developed. Several solid-packed techniques such as stuffing with inert material, chemical deoxidizing, gas-absorbing and sealing were employed to prevent the W-Re thermocouples from oxidizing. Based on comprehensive consideration of various parameters in process industries, a series of industrial W-Re thermocouples has been successfully used in oxidizing and reducing atmospheres, high temperature alkali and other harsh environments. The service life is 6 to 12 months in strong oxidizing atmosphere of Cr2O3-Al2O3 brick kiln and 2 to 3 months in high temperature alkali and in reducing atmosphere of CO.

49 CFR 173.35 - Hazardous materials in IBCs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... plastic or composite IBC may only be filled with a liquid having a vapor pressure less than or equal to... -57 portable tanks. (j) No IBC may be filled with a Packing Group I liquid. Rigid plastic, composite... point of 60 °C (140 °F) (closed cup) or lower, or powders with the potential for dust explosion...

The effect of graphitic target density on carbon nanotube synthesis by pulsed laser ablation method

NASA Astrophysics Data System (ADS)

Kazeimzadeh, Fatemeh; Malekfar, Rasoul; Houshiar, Mahboubeh

2018-01-01

Carbon nanotube (CNT) was synthesized by pulsed laser ablation (PLA) of a graphitic target in vacuum chamber filled by argon gas. The effect of different condition of target preparation on the amount and quality of carbon nanotube generation was investigated. The graphite powder with 2 at% micrometer nickel (Ni) powder was mixed and packed in to a mold using a hydraulic press device at a pressure of 1000 kg/cm3. The obtained pellet which contained the mixture powder provided the carbon source for CNTs formation in PLA method. Two pellets with the pressure time of 15 and 200 min was prepared. It has been shown that the time which graphitic target is under pressure is an effective parameter that can increase the amount of produced CNTs. Field emission scanning electron microscopy (FESEM) images show that if the density of graphitic target is increased by raising up the pressure time, CNTs can grow even under the condition in which usually no nanotube can be formed. It can be due to the elimination of the distances between the graphite and catalyst grains that causes the catalysis performance improvement. The experiment was performed for nanometer cobalt ferrite (CoFe2O4) together with Ni catalyst particles too. The diameter of synthesized CNPs was larger in the case of pure nickel that is related to the size of catalysts. Moreover, it was also observed that the production rate of the nanotubes increased for high density targets. This shows that the results are independent of the type of catalyst.

[Determination of residual acetone in soybean phospholipids by headspace gas chromatography].

PubMed

Shen, S C; Zhang, W B; Cui, L X

2000-11-01

Soybean phospholipids have many functions and alimentary actions. In our country, powder soybean phospholipids are generally got by extraction with acetone, followed by vacuum drying. There may be some residual acetone present in the soybean phospholipids, which is harmful to health. So, we must know residual acetone content in the soybean phospholipids. However we have not found a method to determine the residual acetone in the soybean phospholipids. In this paper, headspace GC was used to determine residual acetone in powder soybean phospholipids. The headspace bottle was glass with a volume of 15 milliliters. Certain amounts of water, ammonium sulfate, and sample were added into the bottle. The mixture was made into a brei as soon as possible. The bottle was put into a water bath at 40 degrees C for an hour. The GC column was a 2 m x 3 mm i.d. stainless steel tube packed with GDX-103 stationary phase. Temperatures of both injector and detector were kept at 120 degrees C. Column temperature was 160 degrees C. Injection volume was 1 mL. External standard method was used for quantitation. The RSD was 1.2%. The recoveries in the range of 25.0 micrograms/g-100 micrograms/g were 98.4%-104%.

Studies on aluminium leaching from cookware in tea and coffee and estimation of aluminium content in toothpaste, baking powder and paan masala.

PubMed

Rajwanshi, P; Singh, V; Gupta, M K; Kumari, V; Shrivastav, R; Ramanamurthy, M; Dass, S

1997-01-30

Studies were conducted in order to assess the level of aluminium (Al) in samples of Indian tea, coffee, toothpaste, paan masala (mouth freshener) and baking powder. Leaching of Al from cookware while preparing tea and coffee was also studied. Experiments were also conducted to study the sequential leaching of Al from cookware by preparing tea and coffee in the presence of standard size Al sheets (coupons). A small amount of Al was found to have leached from coupons during preparation of tea. Tea leaves, were found to be a rich source of Al and a maximum of 2.2% Al is extracted in tea infusions. Coffee powder on the other hand was not found to be a rich source of Al. Baking powder was found to be a rich source of Al and 1 kg of cake prepared with 1-3 teaspoon of baking powder may contain 2-12.7 mg of Al in each serving (25 g). Toothpaste also contains a significant quantity of Al, more so, when packed in Al tubes. Ingestion pattern of Al from these items by humans is also discussed.

Food Allergies and Australian Combat Ration Packs

DTIC Science & Technology

2010-05-01

Beef Noodles , Beef Soup, Beef Teriyaki, Candy Chocolate (M&M’s), Chewing Gum, Chicken Noodles , Chicken Soup, Chocolate Beverage Powder, Chocolate...Minced with Tortellini, Beef Noodles , Beef Soup, Beef Teriyaki, Blackcurrant Fruit Grains, Candy Chocolate (M&M’s), Chewing Gum, Chicken Curry...Chicken Italiano, Chicken Noodles , Chicken Soup, Chocolate Ration, Crispbread Biscuit, Forest Fruits Muesli Bar, Hard Candy, Krispie Biscuit, Lamb with

The Packing and Jamming of Real Polymer Chains

NASA Astrophysics Data System (ADS)

Xue, Gi; Teng, Chao

2010-03-01

Jamming make a hope to unifying theme for granular materials, glasses and threshold behavior in materials. Here we experimentally prepared a real polymer (polystyrene, PS) with various packing density which was described by inter-segment distances (r) detected by NMR. We cold-pressed PS powder at 20 ^oC (with shearing) and then released the pressure. We found that a transparent pellet with high modulus was formed. PS is usually manufactured by a hot-melting process at 180 ^oC. The rigidity and transparency of our cold-pressed pellet and its accuracy of the form are testimony that the PS powder once flowed under cold compression to take the shape of its container. This shear-induced melting is exactly what is expected within the jamming picture. By measuring r and the applied pressure σ under which the polymer chain starts to flow, we drew a schematic jamming phase diagram. The σ-r curve for a real polymer is convex at r < 0.5 nm, while it becomes concave as r is larger than 1 nm. It is the van der Waals attraction that acts as a confining pressure on segments, and makes the σ-r curve convex on the very short scales.

Black pepper powder microbiological quality improvement using DBD systems in atmospheric pressure

NASA Astrophysics Data System (ADS)

Grabowski, Maciej; Hołub, Marcin; Balcerak, Michał; Kalisiak, Stanisław; Dąbrowski, Waldemar

2015-07-01

Preliminary results are given regarding black pepper powder decontamination using dielectric barrier discharge (DBD) plasma in atmospheric pressure. Three different DBD reactor constructions were investigated, both packaged and unpackaged material was treated. Due to potential, industrial applications, in addition to microbiological results, water activity, loss of mass and the properties of packaging material, regarding barrier properties were investigated. Argon based treatment of packed pepper with DBD reactor configuration is proposed and satisfactory results are presented for treatment time of 5 min or less. Contribution to the topical issue "The 14th International Symposium on High Pressure Low Temperature Plasma Chemistry (HAKONE XIV)", edited by Nicolas Gherardi, Ronny Brandenburg and Lars Stollenwark

The stability of self-organized 1-nonanethiol-capped gold nanoparticle monolayer

NASA Astrophysics Data System (ADS)

Jiang, Peng; Xie, Si-shen; Yao, Jian-nian; Pang, Shi-jin; Gao, Hong-jun

2001-08-01

1-Nonanethiol-protected gold nanoparticles with the size of about 2 nm have been prepared by a wet chemical method through choosing a suitable ratio of Au:S (2.5:1). Size selective precipitation of nanoparticles has been used to narrow their size distribution, which facilitates the formation of an ordered nanoparticle close-packed structure. A Fourier transform infrared investigation provides the evidence of the encapsulation of Au nanoparticles by 1-nonanethiol while an ultraviolet-visible spectrum shows a broad absorption around 520 nm, corresponding to surface plasmon band of Au nanoparticles. X-ray photoelectron spectroscopy of the samples demonstrates the metallic state of the gold (Au0) and the existence of sulfur (S). The data from x-ray powder diffraction measurements confirm that the gold nanoparticles have the same face-centred cubic crystalline structure as the bulk gold phase. Finally, transmission electron microscopy (TEM) characterization indicates that the size of the monodisperse colloidal gold nanoparticles is about 2 nm and they can self-organize to form a two-dimensional hexagonal close-packed structure after evaporating a concentrated drop of nanoparticles-toluene solution on a carbon-coated TEM copper grid.

Time-Dependent Solid State Polymorphism of a Series of Donor-Acceptor Dyads

PubMed Central

Peebles, Cameron; Alvey, Paul M.; Lynch, Vincent; Iverson, Brent L.

2014-01-01

In order to exploit the use of favorable electrostatic interactions between aromatic units in directing the assembly of donor-acceptor (D-A) dyads, the present work examines the ability of conjugated aromatic D-A dyads with symmetric side chains to exhibit solid-state polymorphism as a function of time during the solid formation process. Four such dyads were synthesized and their packing in the solid-state from either slower (10-20 days) or faster (1-2 days) evaporation from solvent was investigated using single crystal X-ray analysis and powder X-ray diffraction. Two of the dyads exhibited tail-to-tail (A-A) packing upon slower evaporation from solvent and head-to-tail (D-A) packing upon faster evaporation from solvent. A combination of single crystal analysis and XRD patterns were used to create models wherein a packing model for the other two dyads is proposed. Our findings suggest that while side chain interactions in asymmetric aromatic dyads can play an important role in enforcing segregated D-A dyad assembly, slowly evaporating symmetrically substituted aromatic dyads allows for favorable electrostatic interactions between the aromatic moieties to facilitate the organization of the dyads in the solid-state. PMID:24678269

NiTi-Nb micro-trusses fabricated via extrusion-based 3D-printing of powders and transient-liquid-phase sintering.

PubMed

Taylor, Shannon L; Ibeh, Amaka J; Jakus, Adam E; Shah, Ramille N; Dunand, David C

2018-06-15

We present a novel additive manufacturing method for NiTi-Nb micro-trusses combining (i) extrusion-based 3D-printing of liquid inks containing NiTi and Nb powders, solvents, and a polymer binder into micro-trusses with 0/90° ABAB layers of parallel, ∼600 µm struts spaced 1 mm apart and (ii) subsequent heat-treatment to remove the binder and solvents, and then bond the NiTi powders using liquid phase sintering via the formation of a transient NiTi-Nb eutectic phase. We investigate the effects of Nb concentration (0, 1.5, 3.1, 6.7 at.% Nb) on the porosity, microstructure, and phase transformations of the printed NiTi-Nb micro-trusses. Micro-trusses with the highest Nb content exhibit long channels (from 3D-printing) and struts with smaller interconnected porosity (from partial sintering), resulting in overall porosities of ∼75% and low compressive stiffnesses of 1-1.6 GPa, similar to those of trabecular bone and in agreement with analytical and finite element modeling predictions. Diffusion of Nb into the NiTi particles from the bond regions results in a Ni-rich composition as the Nb replaces Ti atoms, leading to decreased martensite/austenite transformation temperatures. Adult human mesenchymal stem cells seeded on these micro-trusses showed excellent viability, proliferation, and extracellular matrix deposition over 14 days in culture. Near-equiatomic NiTi micro-trusses are attractive for biomedical applications such as stents, actuators, and bone implants because of their combination of biocompatibility, low compressive stiffness, high surface area, and shape-memory or superelasticity. Extrusion-based 3D-printing of NiTi powder-based inks into micro-trusses is feasible, but the subsequent sintering of the powders into dense struts is unachievable due to low diffusivity, large particle size, and low packing density of the NiTi powders. We present a solution, whereby Nb powders are added to the NiTi inks, thus forming during sintering a eutectic NiTi-Nb liquid phase which bonds the solid NiTi powders and improves densification of the struts. This study investigates the microstructure, porosity, phase transformation behavior, compressive stiffness, and cytocompatibility of these printed NiTi-Nb micro-trusses. Copyright © 2018 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Packing and deploying Soft Origami to and from cylindrical volumes with application to automotive airbags

PubMed Central

Nelson, Todd G.; Zimmerman, Trent K.; Fernelius, Janette D.; Magleby, Spencer P.; Howell, Larry L.

2016-01-01

Packing soft-sheet materials of approximately zero bending stiffness using Soft Origami (origami patterns applied to soft-sheet materials) into cylindrical volumes and their deployment via mechanisms or internal pressure (inflation) is of interest in fields including automobile airbags, deployable heart stents, inflatable space habitats, and dirigible and parachute packing. This paper explores twofold patterns, the ‘flasher’ and the ‘inverted-cone fold’, for packing soft-sheet materials into cylindrical volumes. Two initial packing methods and mechanisms are examined for each of the flasher and inverted-cone fold patterns. An application to driver’s side automobile airbags is performed, and deployment tests are completed to compare the influence of packing method and origami pattern on deployment performance. Following deployment tests, two additional packing methods for the inverted-cone fold pattern are explored and applied to automobile airbags. It is shown that modifying the packing method (using different methods to impose the same base pattern on the soft-sheet material) can lead to different deployment performance. In total, two origami patterns and six packing methods are examined, and the benefits of using Soft Origami patterns and packing methods are discussed. Soft Origami is presented as a viable method for efficiently packing soft-sheet materials into cylindrical volumes. PMID:27703707

Packing and deploying Soft Origami to and from cylindrical volumes with application to automotive airbags

NASA Astrophysics Data System (ADS)

Bruton, Jared T.; Nelson, Todd G.; Zimmerman, Trent K.; Fernelius, Janette D.; Magleby, Spencer P.; Howell, Larry L.

2016-09-01

Packing soft-sheet materials of approximately zero bending stiffness using Soft Origami (origami patterns applied to soft-sheet materials) into cylindrical volumes and their deployment via mechanisms or internal pressure (inflation) is of interest in fields including automobile airbags, deployable heart stents, inflatable space habitats, and dirigible and parachute packing. This paper explores twofold patterns, the `flasher' and the `inverted-cone fold', for packing soft-sheet materials into cylindrical volumes. Two initial packing methods and mechanisms are examined for each of the flasher and inverted-cone fold patterns. An application to driver's side automobile airbags is performed, and deployment tests are completed to compare the influence of packing method and origami pattern on deployment performance. Following deployment tests, two additional packing methods for the inverted-cone fold pattern are explored and applied to automobile airbags. It is shown that modifying the packing method (using different methods to impose the same base pattern on the soft-sheet material) can lead to different deployment performance. In total, two origami patterns and six packing methods are examined, and the benefits of using Soft Origami patterns and packing methods are discussed. Soft Origami is presented as a viable method for efficiently packing soft-sheet materials into cylindrical volumes.

Packing and deploying Soft Origami to and from cylindrical volumes with application to automotive airbags.

PubMed

Bruton, Jared T; Nelson, Todd G; Zimmerman, Trent K; Fernelius, Janette D; Magleby, Spencer P; Howell, Larry L

2016-09-01

Packing soft-sheet materials of approximately zero bending stiffness using Soft Origami (origami patterns applied to soft-sheet materials) into cylindrical volumes and their deployment via mechanisms or internal pressure (inflation) is of interest in fields including automobile airbags, deployable heart stents, inflatable space habitats, and dirigible and parachute packing. This paper explores twofold patterns, the 'flasher' and the 'inverted-cone fold', for packing soft-sheet materials into cylindrical volumes. Two initial packing methods and mechanisms are examined for each of the flasher and inverted-cone fold patterns. An application to driver's side automobile airbags is performed, and deployment tests are completed to compare the influence of packing method and origami pattern on deployment performance. Following deployment tests, two additional packing methods for the inverted-cone fold pattern are explored and applied to automobile airbags. It is shown that modifying the packing method (using different methods to impose the same base pattern on the soft-sheet material) can lead to different deployment performance. In total, two origami patterns and six packing methods are examined, and the benefits of using Soft Origami patterns and packing methods are discussed. Soft Origami is presented as a viable method for efficiently packing soft-sheet materials into cylindrical volumes.

The filling of powdered herbs into two-piece hard capsules using hydrogenated cotton seed oil as lubricant.

PubMed

Aling, Joanna; Podczeck, Fridrun

2012-11-20

The aim of this work was to investigate the plug formation and filling properties of powdered herbal leaves using hydrogenated cotton seed oil as an alternative lubricant. In a first step, unlubricated and lubricated herbal powders were studied on a small scale using a plug simulator, and low-force compression physics and parameterization techniques were used to narrow down the range in which the optimum amount of lubricant required would be found. In a second step these results were complemented with investigations into the flow properties of the powders based on packing (tapping) experiments to establish the final optimum lubricant concentration. Finally, capsule filling of the optimum formulations was undertaken using an instrumented tamp filling machine. This work has shown that hydrogenated cotton seed oil can be used advantageously for the lubrication of herbal leaf powders. Stickiness as observed with magnesium stearate did not occur, and the optimum lubricant concentration was found to be less than that required for magnesium stearate. In this work, lubricant concentrations of 1% or less hydrogenated cotton seed oil were required to fill herbal powders into capsules on the instrumented tamp-filling machine. It was found that in principle all powders could be filled successfully, but that for some powders the use of higher compression settings was disadvantageous. Relationships between the particle size distributions of the powders, their flow and consolidation as well as their filling properties could be identified by multivariate statistical analysis. The work has demonstrated that a combination of the identification of plug formation and powder flow properties is helpful in establishing the optimum lubricant concentration required using a small quantity of powder and a powder plug simulator. On an automated tamp-filling machine, these optimum formulations produced satisfactory capsules in terms of coefficient of fill weight variability and capsule weight. Copyright © 2012 Elsevier B.V. All rights reserved.

Crystal growth, spectral, structural and optical studies of π-conjugated stilbazolium crystal: 4-bromobenzaldehyde-4'-N'-methylstilbazolium tosylate.

PubMed

Krishna Kumar, M; Sudhahar, S; Bhagavannarayana, G; Mohan Kumar, R

2014-05-05

Nonlinear optical (NLO) organic compound, 4-bromobenzaldehyde-4'-N'-methylstilbazolium tosylate was synthesized by reflux method. The formation of molecular complex was confirmed from (1)H NMR, FT-IR and FT-Raman spectral analyses. The single crystals were grown by slow evaporation solution growth method and the crystal structure and atomic packing of grown crystal was identified. The morphology and growth axis of grown crystal were determined. The crystal perfection was analyzed using high resolution X-ray diffraction study on (001) plane. Thermal stability, decomposition stages and melting point of the grown crystal were analyzed. The optical absorption coefficient (α) and energy band gap (E(g)) of the crystal were determined using UV-visible absorption studies. Second harmonic generation efficiency of the grown crystal was examined by Kurtz powder method with different particle size using 1064 nm laser. Laser induced damage threshold study was carried out for the grown crystal using Nd:YAG laser. Copyright © 2014 Elsevier B.V. All rights reserved.

Compaction of granular materials composed of deformable particles

NASA Astrophysics Data System (ADS)

Nguyen, Thanh Hai; Nezamabadi, Saeid; Delenne, Jean-Yves; Radjai, Farhang

2017-06-01

In soft particle materials such as metallic powders the particles can undergo large deformations without rupture. The large elastic or plastic deformations of the particles are expected to strongly affect the mechanical properties of these materials compared to hard particle materials more often considered in research on granular materials. Herein, two numerical approaches are proposed for the simulation of soft granular systems: (i) an implicit formulation of the Material Point Method (MPM) combined with the Contact Dynamics (CD) method to deal with contact interactions, and (i) Bonded Particle Model (BPM), in which each deformable particle is modeled as an aggregate of rigid primary particles using the CD method. These two approaches allow us to simulate the compaction of an assembly of elastic or plastic particles. By analyzing the uniaxial compaction of 2D soft particle packings, we investigate the effects of particle shape change on the stress-strain relationship and volume change behavior as well as the evolution of the microstructure.

Electrochemical to Mechanical Energy Conversion

DTIC Science & Technology

2010-02-01

advantage of these properties . Metal alloys fit these requirements as many of them dilate in excess of 100% when alloyed with lithium. Aluminum, in...3. Woo KC, Kamitakahara WA, DiVincenzo DP, et al . Effect of In-Plane Density on the Structural and Elastic Properties of Graphite Intercalation...Further, free volume associated with the powder packing of the electrodes or the sealing process will aid in stress relaxation and creep strain. (a) (b) 35

Measuring Trace Hydrocarbons in Silanes

NASA Technical Reports Server (NTRS)

Lesser, L. A.

1984-01-01

Technique rapid and uses standard analytical equipment. Silane gas containing traces of hydrocarbons injected into carrier gas of moist nitrogen having about 0.2 percent water vapor. Carrier, water and silane pass through short column packed with powdered sodium hydroxide which combines moisture and silane to form nonvolatile sodium silicate. Carrier gas free of silane but containing nonreactive hydrocarbons, pass to silica-gel column where chromatographic separation takes place. Hydrocarbons measured by FID.

Fort A.P. Hill Soil Permittivity and Conductivity Measurements for the Wide Area Airborne Minefield Detection Program

DTIC Science & Technology

2003-09-01

4 3. Purpose 4 4. Description of Test Equipment 4 4.1 Damaskos Model 3000T Liquid/Powder Cell Permittivity...Permeability System ..........4 4.2 HP8510 Network Analyzer/ Damaskos System Overview..............................................5 5. Soil Sample Site...Permittivity and conductivity values were measured from 100 to 3000 MHz. The soil samples were packed as tight as possible into the Damaskos

Chromium and reactive element modified aluminide diffusion coatings on superalloys - Environmental testing

NASA Technical Reports Server (NTRS)

Bianco, Robert; Rapp, Robert A.; Smialek, James L.

1993-01-01

The high temperature performance of reactive element (RE)-doped and Cr/RE-modified aluminide diffusion coatings on commercial Ni-base alloy substrates was determined. In isothermal oxidation at 1100 C in air, RE-doped aluminide coatings on IN 713LC substrates formed a continuous slow-growing n-Al2O3 scale after 44 hrs of exposure. The coatings were protected by either an outer ridge Al2O3 scale with an inner compact Al2O3 scale rich in RE or by a continuous compact scale without any noticeable cracks or flaws. The cyclic oxidation behavior of Cr/RE-modified aluminide coatings on Rene 80 and IN 713LC alloys and of RE-doped aluminide coatings on IN 713LC alloys at 1100 C in static air was determined. Pack powder entrapment from the powder contacting (PC) process detracted significantly from the overall cyclic oxidation performance. Type I hot corrosion behavior of Cr/RE-modified aluminide coatings on Rene 80 and Mar-M247 alloy substrates at 900 C in a catalyzed 0.1 percent SO3/O3 gas mixture was determined. The modified coatings produced from the PC arrangement provided significantly better resistance to hot corrosion attack than commercial low-activity aluminide coatings produced by the above pack arrangement.

Improved properties of fine active pharmaceutical ingredient powder blends and tablets at high drug loading via dry particle coating.

PubMed

Kunnath, Kuriakose; Huang, Zhonghui; Chen, Liang; Zheng, Kai; Davé, Rajesh

2018-05-30

It has been shown that dry coating cohesive active pharmaceutical ingredients (APIs) with nano-silica can improve packing and flow of their blends, facilitating high speed direct compression tableting. This paper examines the broader scope and generality of previous work by examining three fine APIs; micronized Acetaminophen (mAPAP), coarse Acetaminophen (cAPAP) and micronized Ibuprofen (mIBU), and considers dry coating with both hydrophobic or hydrophilic nano-silica to examine the effect not only on packing density and flow of their blends, but also dissolution and tensile strength of their tablets. The impact of the excipient size on blend and tablet properties are also investigated, indicating blend flow is most improved when matching API particle size with excipient particle size. In all cases where the API is dry coated, the blend packing and flow improve, so as to suggest such high drug loaded blends could enable direct compression. Using dry coated API along with finer excipients in blends lead to improved hardness of the corresponding tablets. Interestingly, dissolution profiles show dry coated API tablets generally have faster dissolution rates, regardless of silica hydrophilicity, suggesting API powder deagglomeration via nano-silica coating plays a crucial role. The most significant conclusion is that, although there are differences in properties of blends that depend on the API, hydrophobic or hydrophilic nano-silica coating, as well as large or fine excipients, in all cases, dry coating of APIs significantly improves the possibility of using the specific blend at high drug loading in direct compression tableting. Copyright © 2018 Elsevier B.V. All rights reserved.

The effects of ball size distribution on attritor efficiency

NASA Astrophysics Data System (ADS)

Cook, T. M.; Courtney, T. H.

1995-09-01

A study was undertaken to determine how media dynamics are altered when differently sized grinding balls are used in an attritor. Cinematographic techniques identify the extent of segregation/mixing of the differently sized balls within the attritor as a function of impeller rotational velocity and small ball number fraction. This permits determination of rotational velocities needed to most efficiently use the tactic of milling with differently sized media. Cinematographic observations show that the close-packed media array, assumed when balls of the same size are used for milling, is disrupted when differently sized balls are used. Monitoring powder particle numbers as a function of milling time for the situations when the same and differently sized balls are used can be used to assess relative milling efficiencies. Results indicate powder deformation, fracture, and welding are enhanced through employment of differently sized balls. This conclusion is reinforced by observations of microstructural characteristics of powder processed with the different type of media.

Heat Transfar Properties of Flat-Panel Evacuated Porous Insrlators

NASA Astrophysics Data System (ADS)

Yoneno, Hirosyi; Yamamoto, Ryoichi

Flat Panel evacuated porous insulators have been produced by filling powder or fiber (such as perlite powder, diatomaceous earth powder, silica aerogel powder, g lass fiber and ceramic fiber) in film-like laminated plastic container and by evacuating to form vacuum in it is interior. Heat transfer properties of these evacuated insulators have been studied under various conditions (such as particle diameter, surface area, packing density, solid volume fraction and void dimension). The apparent mean thermal conductivity has been measured for the boundary surface temperature at cold face temperature 13°C and hot face temperature 35°. The effect of air pressure ranging from 1 Pa to one atomosphere (105 Pa) was examined. The results were as follows. (1) For each powder the apparent mean thermal conductivity decreases with decreasing residual air pressure, and at very low pressure bellow 1 -103 Pa the conductivity becomes indeqendent of pressure. The thermal conductivity at 1.3Pa is 0.0053 W/mK for perlite powder, 0.0048W/mK for diatomaceous earth powder, 0.0043 W/mK for silica aerogel powder and 0.0029W/mK for glass fiber. (2) With decreasing particle size, the apparent mean thermal conductivity is constant independent of residual air pressure in higher pressure region. It is that void dimension continues to decrease with particle size and the mean free path of air becomes comparable with void dimension. (3) In the range of minor solid volume fraction, the apparent mean thermal conductivity at very low precreases with decreasing particle size. This shows the thermal contact resistance of the solid particle increases with decreasing particle size.

Formation and magnetic properties of the L10 phase in bulk, powder and hot compacted Mn-Ga alloys

NASA Astrophysics Data System (ADS)

Mix, T.; Müller, K.-H.; Schultz, L.; Woodcock, T. G.

2015-10-01

The formation and stability of the L10 phase in Mn-Ga binary alloys with compositions in the range 50-75 at% Mn (in steps of 5 at%) has been studied. Of these, single-phase L10 structure was successfully produced in the 55, 60 and 65 at% Mn alloys by annealing the high temperature phases, which had been retained to room temperature following arc melting. Further annealing and thermal analysis were used to determine the phase transformation temperatures in the alloys and the results were used to guide further processing. The saturation magnetisation, Ms, and the anisotropy field, Ha, were determined in applied fields up to 14 T. For Mn55Ga45, μ0Ms=0.807 T and μ0Ha=4.4 T were observed. Mechanically milled Mn55Ga45 powder had coercivity of μ0Hc=0.393 T, which was a twentyfold increase compared to the bulk material but the magnetisation was reduced (cf. powder: μ0M5 T=0.576 T, bulk: μ0M5 T=0.780 T). Annealing the powder at 400 °C led to recovery of the magnetisation but reduced the coercivity, which was still 10 times as high as the bulk value. A degree of texture of 0.45 was achieved by magnetic alignment of the powder particles, leading to a remanence of 0.526 T. Furthermore, isotropic hot compacts of powders were produced with packing density from 83% to 99%, in which the improved coercivity of the powders was partially retained.

Understanding the effects of process parameters on the properties of cold gas dynamic sprayed pure titanium coatings

NASA Astrophysics Data System (ADS)

Wong, Wilson

The cold gas dynamic spraying of commercially pure titanium coatings was investigated. Specifically, the relationship between several key cold spray parameters on the quality of the resulting coatings was studied in order to gain a more thorough understanding of the cold spray process. To achieve this goal, three distinct investigations were performed. The first part of the investigation focussed on the effect of propelling gas, particularly helium and nitrogen, during the cold spraying of titanium coatings. Coatings were characterised by SEM and were evaluated for their deposition efficiency (DE), microhardness, and porosity. In selected conditions, three particle velocities were investigated such that for each condition, the propelling gasses temperature and pressure were attuned to attain similar particle velocities for each gas. In addition, a thick and fully dense cold sprayed titanium coating was achieved with optimised spray parameters and nozzle using helium. The corresponding average particle velocity was 1173 m/s. The second part of the investigation studied the effect of particle morphology (spherical, sponge, and irregular) and size distributions (mean particle sizes of 20, 29, and 36 mum) of commercially pure titanium on the mechanical properties of the resulting cold sprayed coatings. Numerous powder and coating characterisations were performed. From these data, semi-empirical flow (stress-strain) curves were generated based on the Johnson-Cook plasticity model which could be used as a measure of cold sprayability. Cold sprayability can be defined as the ease with which a powder can be cold sprayed. It was found that the sponge and irregular commercially pure titanium powders had higher oxygen content, poorer powder flowability, higher compression ratio, lower powder packing factor, and higher average particle impact velocities compared to the spherical powders. XRD results showed no new phases present when comparing the various feedstock powders to their corresponding coatings. For all feedstock powder morphologies, it was observed that the larger the particle size, the higher the temperature generated on impact. For the spherical powders, the higher the temperature generated on impact, the lower the stress needed to deform the particle. In addition, as the kinetic energy of the impacting particle increased, the flow peak stress decreased while the final strain increased. Furthermore, higher final flow strains were associated with higher coating DeltaHV 10 (between the coatings and the feedstock powders). Similar relationships are expected to exist for the sponge and irregular feedstock powders. Based on porosity, the spherical medium powder was found to have the best cold sprayability. The final part of the investigation focussed on the effect of substrate surface roughness and coating thickness on the adhesion strength of commercially pure titanium cold sprayed coatings onto Steel 1020, Al 6061, and Ti substrates. Adhesion strength was measured by tensile/pull tests according to ASTM C-633-01 standard. Through-thickness residual stresses of selected coatings were measured using the modified layer removal method (MLRM). In addition, mean coating residual stresses were calculated from MLRM results. It was found that adhesion strength increases with increasing substrate surface roughness and decreases with increasing coating thickness. Furthermore, mean coating residual stresses were correlated with adhesion strength and it was suggested that higher adhesion strengths are associated with higher mean compressive stresses and a higher probability for adiabatic shear instability to occur due to the higher particle impact velocities. In general, it was found that under similar cold spray conditions and substrate surface preparation method, adhesion strength was strongest for commercially pure titanium coatings deposited onto Al 6061, followed by Ti, then Steel 1020.

Miniature Autonomous Rocket Recovery System (MARRS)

DTIC Science & Technology

2011-05-01

composed of approximately 4 to 6 cubic centimeters of FFFF black powder. C. Rocket System Structure The rocket body was an epoxy-laden phenolic ... Kevlar line upon which was the lower main parachute; a 50” Rocket Rage Parachute. The booster had a 70” Rocket Rage parachute. In order to protect...the parachutes from burns, the parachutes were wrapped in protective Kevlar cloth and a layer of flame-retardant cellulose was packed in between the

Uniaxial Tensile Strength and Flaw Characterization of SiC-N

DTIC Science & Technology

2014-01-01

study has been largely limited to tiles less than 40 mm thick, especially versus small caliber threats (1, 3, 4). Research and production of ceramic... production of very large ceramic components. One issue that may occur in the production of large ceramic components is uneven powder packing during the...flaw is important because flaws originate from different stages during the production process. Flaws associated with the processing of the material

Solid state 13C-NMR, infrared, X-ray powder diffraction and differential thermal studies of the homologous series of some mono-valent metal (Li, Na, K, Ag) n-alkanoates: A comparative study

NASA Astrophysics Data System (ADS)

Nelson, Peter N.; Ellis, Henry A.; White, Nicole A. S.

2015-06-01

A comparative study of the molecular packing, lattice structures and phase behaviors of the homologous series of some mono-valent metal carboxylates (Li, Na, K and Ag) is carried out via solid state FT-infrared and 13C-NMR spectroscopes, X-rays powder diffraction, density measurements, differential scanning calorimetry, polarizing light microscopy and variable temperature infrared spectroscopy. It is proposed that, for lithium, sodium and potassium carboxylates, metal-carboxyl coordination is via asymmetric chelating bidentate bonding with extensive intermolecular interactions to form tetrahedral metal centers, irrespective of chain length. However, for silver n-alkanoates, carboxyl moieties are bound to silver ions via syn-syn type bridging bidentate coordination to form dimeric units held together by extensive head group inter-molecular interactions. Furthermore, the fully extended hydrocarbon chains which are crystallized in the all-trans conformation are tilted at ca. 30°, 27°, 15° and 31° with respect to a normal to the metal plane, for lithium, sodium, silver and potassium carboxylates, respectively. All compounds are packed as lamellar bilayer structures, however, lithium compounds are crystallized in a triclinic crystal system whilst silver, sodium and potassium n-alkanoates are all monoclinic with possible P1 bravais lattice. Odd-even alternation observed in various physical features is associated with different inter-planar spacing between closely packed layers in the bilayer which are not in the same plane; a phenomenon controlled by lattice packing symmetry requirements. All compounds, except silver carboxylates, show partially reversibly first order pre-melting transitions; the number of which increases with increasing chain length. These transitions are associated, for the most part, with lamellar collapse followed by increased gauche-trans isomerism in the methylene group assembly, irrespective of chain length. It is proposed that the absence of mesomorphic transitions in their phase sequences is due to a lack of sufficient balance between attractive and repulsive electrostatic and van der Waals forces during phase change. The evidence presented in this study shows that phase behaviors of mono-valent metal carboxylates are controlled, mainly, by head group bonding.

System and Method for High-Speed Data Recording

NASA Technical Reports Server (NTRS)

Taveniku, Mikael B. (Inventor)

2017-01-01

A system and method for high speed data recording includes a control computer and a disk pack unit. The disk pack is provided within a shell that provides handling and protection for the disk packs. The disk pack unit provides cooling of the disks and connection for power and disk signaling. A standard connection is provided between the control computer and the disk pack unit. The disk pack units are self sufficient and able to connect to any computer. Multiple disk packs are connected simultaneously to the system, so that one disk pack can be active while one or more disk packs are inactive. To control for power surges, the power to each disk pack is controlled programmatically for the group of disks in a disk pack.

Alterations of thorium oxalate morphology by changing elementary precipitation conditions

NASA Astrophysics Data System (ADS)

Tyrpekl, V.; Beliš, M.; Wangle, T.; Vleugels, J.; Verwerft, M.

2017-09-01

Oxalates of actinide elements are widely used in research and industry mainly due to their low solubility in aqueous solution and easy conversion to oxide. Although thorium oxide is worldwide mostly produced by the oxalate precipitation and conversion route, the powder morphology obtained through this process is known to inhibit the packing and sintering step of the pellet production. The presented work investigates the effects of oxalate precipitation conditions on the final powder morphology. Among the precipitation conditions considered are: pH of the thorium feed solution, concentration, temperature and the order of addition (thorium solution in oxalic acid solution and vice versa) known as reverse/direct strike. Herein, we show that the morphology of the final oxalate depends significantly on the above mentioned precipitation parameters.

Granular compaction by fluidization

NASA Astrophysics Data System (ADS)

Tariot, Alexis; Gauthier, Georges; Gondret, Philippe

2017-06-01

How to arrange a packing of spheres is a scientific question that aroused many fundamental works since a long time from Kepler's conjecture to Edward's theory (S. F. Edwards and R.B.S Oakeshott. Theory of powders. Physica A, 157: 1080-1090, 1989), where the role traditionally played by the energy in statistical problems is replaced by the volume for athermal grains. We present experimental results on the compaction of a granular pile immersed in a viscous fluid when submited to a continuous or bursting upward flow. An initial fluidized bed leads to a well reproduced initial loose packing by the settling of grains when the high enough continuous upward flow is turned off. When the upward flow is then turned on again, we record the dynamical evolution of the bed packing. For a low enough continuous upward flow, below the critical velocity of fluidization, a slow compaction dynamics is observed. Strikingly, a slow compaction can be also observed in the case of "fluidization taps" with bursts of fluid velocity higher than the critical fluidization velocity. The different compaction dynamics is discussed when varying the different control parameters of these "fluidization taps".

A Fully Nonmetallic Gas Turbine Engine Enabled by Additive Manufacturing of Ceramic Composites. Part III; Additive Manufacturing and Characterization of Ceramic Composites

NASA Technical Reports Server (NTRS)

Halbig, Michael C.; Grady, Joseph E.; Singh, Mrityunjay; Ramsey, Jack; Patterson, Clark; Santelle, Tom

2015-01-01

This publication is the third part of a three part report of the project entitled "A Fully Nonmetallic Gas Turbine Engine Enabled by Additive Manufacturing" funded by NASA Aeronautics Research Institute (NARI). The objective of this project was to conduct additive manufacturing to produce ceramic matrix composite materials and aircraft engine components by the binder jet process. Different SiC powders with median sizes ranging from 9.3 to 53.0 microns were investigated solely and in powder blends in order to maximize powder packing. Various infiltration approaches were investigated to include polycarbosilane (SMP-10), phenolic, and liquid silicon. Single infiltrations of SMP-10 and phenolic only slightly filled in the interior. When the SMP-10 was loaded with sub-micron sized SiC powders, the infiltrant gave a much better result of filling in the interior. Silicon carbide fibers were added to the powder bed to make ceramic matrix composite materials. Microscopy showed that the fibers were well distributed with no preferred orientation on the horizontal plane and fibers in the vertical plane were at angles as much as 45deg. Secondary infiltration steps were necessary to further densify the material. Two to three extra infiltration steps of SMP-10 increased the density by 0.20 to 0.55 g/cc. However, the highest densities achieved were 2.10 to 2.15 g/cc. Mechanical tests consisting of 4 point bend tests were conducted. Samples from the two CMC panels had higher strengths and strains to failure than the samples from the two nonfiber reinforced panels. The highest strengths were from Set N with 65 vol% fiber loading which had an average strength of 66 MPa. Analysis of the fracture surfaces did not reveal pullout of the reinforcing fibers. Blunt fiber failure suggested that there was not composite behavior. The binder jet additive manufacturing method was used to also demonstrate the fabrication of turbine engine vane components of two different designs and sizes. The binder jet method has benefits over the conventional manufacturing of CMCs in that prototype and production parts can be fabricated quickly and economically with no tooling and extensive hand layup.

Can Csbnd H⋯Fsbnd C hydrogen bonds alter crystal packing features in the presence of Nsbnd H⋯Odbnd C hydrogen bond?

NASA Astrophysics Data System (ADS)

Yadav, Hare Ram; Choudhury, Angshuman Roy

2017-12-01

Intermolecular interactions involving organic fluorine have been the contemporary field of research in the area of organic solid state chemistry. While a group of researchers had refuted the importance of "organic fluorine" in guiding crystal structures, others have provided evidences for in favor of fluorine mediated interactions in the solid state. Many systematic studies have indicated that the "organic fluorine" is capable of offering weak hydrogen bonds through various supramolecular synthons, mostly in the absence of other stronger hydrogen bonds. Analysis of fluorine mediated interaction in the presence of strong hydrogen bonds has not been highlighted in detail. Hence a thorough structural investigation is needed to understand the role of "organic fluorine" in crystal engineering of small organic fluorinated molecules having the possibility of strong hydrogen bond formation in the solution and in the solid state. To fulfil this aim, we have synthesized a series of fluorinated amides using 3-methoxyphenylacetic acid and fluorinated anilines and studied their structural properties through single crystal and powder X-ray diffraction methods. Our results indicated that the "organic fluorine" plays a significant role in altering the packing characteristics of the molecule in building specific crystal lattices even in the presence of strong hydrogen bond.

Porosity and mechanical properties of zirconium ceramics

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

Buyakova, S., E-mail: sbuyakova@ispms.tsc.ru; Kulkov, S.; Tomsk Polytechnic University

2015-11-17

Has been studied a porous ceramics obtained from ultra-fine powders. Porous ceramic ZrO{sub 2}(MgO), ZrO{sub 2}(Y{sub 2}O{sub 3}) powder was prepared by pressing and subsequent sintering of compacts homologous temperatures ranging from 0.63 to 0.56 during the isothermal holding duration of 1 to 5 hours. The porosity of ceramic samples was from 15 to 80%. The structure of the ceramic materials produced from plasma-sprayed ZrO{sub 2} powder was represented as a system of cell and rod structure elements. Cellular structure formed by stacking hollow powder particles can be easily seen at the images of fracture surfaces of obtained ceramics. Theremore » were three types of pores in ceramics: large cellular hollow spaces, small interparticle pores which are not filled with powder particles and the smallest pores in the shells of cells. The cells generally did not have regular shapes. The size of the interior of the cells many times exceeded the thickness of the walls which was a single-layer packing of ZrO{sub 2} grains. A distinctive feature of all deformation diagrams obtained in the experiment was their nonlinearity at low deformations which was described by the parabolic law. It was shown that the observed nonlinear elasticity for low deformation on deformation diagrams is due to mechanical instability of the cellular elements in the ceramic carcass.« less

Synthesis, characterization and experimental investigation of Cu-BTC as CO2 adsorbent from flue gas.

PubMed

Xie, Jiangkun; Yan, Naiqiang; Qu, Zan; Yang, Shijian

2012-01-01

Porous Cu-BTC material was synthesized by the solvothermal method. Powder X-ray diffraction (PXRD) was used to test the phase purity of the synthesized material and investigate its structural stability under the influence of flue gas components. The thermal stability of the material was determined through thermal gravimetric (TG) analysis. Scanning electron microscopy (SEM) was employed to study the microstructure of the material. Cu-BTC was demonstrated not only to have high CO2 adsorption capacity but also good selectivity of CO2 over N2 by means of packed bed tests. The adsorption capacity of Cu-BTC for CO2 was about 69 mL/g at 22 degrees C. The influence of the main flue gas components on the CO2 capacity of the material were discussed as well.

Modeling the arrangement of particles in natural swelling-clay porous media using three-dimensional packing of elliptic disks

NASA Astrophysics Data System (ADS)

Ferrage, Eric; Hubert, Fabien; Tertre, Emmanuel; Delville, Alfred; Michot, Laurent J.; Levitz, Pierre

2015-06-01

Swelling clay minerals play a key role in the control of water and pollutant migration in natural media such as soils. Moreover, swelling clay particles' orientational properties in porous media have significant implications for the directional dependence of fluid transfer. Herein we investigate the ability to mimic the organization of particles in natural swelling-clay porous media using a three-dimensional sequential particle deposition procedure [D. Coelho, J.-F. Thovert, and P. M. Adler, Phys. Rev. E 55, 1959 (1997), 10.1103/PhysRevE.55.1959]. The algorithm considered is first used to simulate disk packings. Porosities of disk packings fall onto a single master curve when plotted against the orientational scalar order parameter value. This relation is used to validate the algorithm used in comparison with existing ones. The ellipticity degree of the particles is shown to have a negligible effect on the packing porosity for ratios ℓa/ℓb less than 1.5, whereas a significant increase in porosity is obtained for higher values. The effect of the distribution of the geometrical parameters (size, aspect ratio, and ellipticity degree) of particles on the final packing properties is also investigated. Finally, the algorithm is used to simulate particle packings for three size fractions of natural swelling-clay mineral powders. Calculated data regarding the distribution of the geometrical parameters and orientation of particles in porous media are successfully compared with experimental data obtained for the same samples. The results indicate that the obtained virtual porous media can be considered representative of natural samples and can be used to extract properties difficult to obtain experimentally, such as the anisotropic features of pore and solid phases in a system.

Inhibition of Listeria monocytogenes in Hot Dogs by Surface Application of Freeze-Dried Bacteriocin-Containing Powders from Lactic Acid Bacteria.

PubMed

Ünlü, Gülhan; Nielsen, Barbara; Ionita, Claudia

2016-06-01

Six lactic acid bacteria (LAB) strains, Lactococcus lactis BFE 920, L. lactis subsp. lactis ATCC 11454, L. lactis subsp. cremoris ATCC 14365, Lactobacillus curvatus L442, Lact. curvatus LTH 1174, and Lact. bavaricus MN, were grown in cheddar cheese whey supplemented with complex nutrient sources. Cell-free culture supernatants were freeze-dried, and the resulting bacteriocin-containing powders were applied on the surface of hot dogs that were inoculated (~4 log cfu/hot dog) with a five-strain Listeria monocytogenes cocktail. Hot dogs were vacuum-sealed and stored at 4 °C for 4 weeks. L. monocytogenes was enumerated, using both tryptic soy agar (TSA) and oxford listeria agar (OXA), on day 0 and at 1, 2, 3, and 4 weeks of the refrigerated storage. In hot dogs containing only the L. monocytogenes inoculum, L. monocytogenes counts increased from 4 up to 7 log cfu/hot dog. All samples containing freeze-dried bacteriocin-containing powders exhibited significantly lowered (P < 0.05) L. monocytogenes populations on the surface of hot dogs throughout the 4-week study except for bavaricin MN powder. Bacterial counts on hot dogs packed without any powder were statistically equal on day 0 when enumerated on OXA. Freeze-dried bacteriocin-containing powders from Lact. curvatus L442 and L. lactis subsp. cremoris ATCC 14365 decreased L. monocytogenes populations on the surface of hot dogs by greater than 2 log cfu/hot dog throughout the 4-week study. For the powdered bacteriocin preparations from L. lactis BFE 920, L. lactis subsp. lactis ATCC 11454, and Lact. curvatus LTH 1174, L. monocytogenes populations were determined to be approximately 3-log cfu/hot dog after 4 weeks of storage.

To evaluate the effect of various magnesium stearate polymorphs using powder rheology and thermal analysis.

PubMed

Okoye, Patrick; Wu, Stephen H; Dave, Rutesh H

2012-12-01

The effects of magnesium stearate (MgSt) polymorphs-anhydrate (MgSt-A), monohydrate (MgSt-M), and dihydrate (MgSt-D)-on rheological properties of powders were evaluated using techniques such as atomic analysis and powder rheometry. Additional evaluation was conducted using thermal analysis, micromeritics, and tableting forces. In this study, binary ratios of neat MgSt polymorphs were employed as lubricants in powder blends containing acetaminophen (APAP), microcrystalline cellulose (MCC), and lactose monohydrate (LAC-M). Powder rheometry was studied using permeability, basic flow energy (BFE), density, and porosity analysis. Thermal conductivity and differential scanning calorimetric analysis of MgSt polymorphs were employed to elucidate MgSt effect on powder blends. The impact of MgSt polymorphs on compaction characteristics were analyzed via tablet compression forces. Finally, the distribution of atomized magnesium (Mg) ions as a function of intensity was evaluated using laser-induced breakdown spectroscopy (LIBS) on tablets. The results from LIBS analysis indicated the dependency of the MgSt polymorphic forms on the atomized Mg ion intensity, with higher Mg ion intensity suggesting higher lubricity index (i.e. greater propensity to over-lubricate). The results from lubricity index suggested the tendency of blends to over-lubricate based on the MgSt polymorphic forms. Finally, tableting forces suggested that MgSt-D and MgSt-A offered processing benefits such as lower ejection and compression forces, and that MgSt-M showed the most stable compression force in single or combined polymorphic ratios. These results suggested that the initial moisture content, crystal arrangement, intra- and inter-molecular packing of the polymorphs defined their effects on the rheology of lubricated powders.

Growth and characterization of barium complex of 1,3,5-triazinane-2,4,6-trione in gel: a corrosion inhibiting material

NASA Astrophysics Data System (ADS)

Divya, R.; Nair, Lekshmi P.; Bijini, B. R.; Nair, C. M. K.; Babu, K. Rajendra

2018-05-01

Good quality prismatic crystals of industrially applicable corrosion inhibiting barium complex of 1,3,5-triazinane-2,4,6-trione have been grown by conventional gel method. The crystal structure, packing, and nature of bonds are revealed in the single crystal X-ray diffraction analysis. The crystal has a three-dimensional polymeric structure having a triclinic crystal system with the space group P-1. The powder X-ray diffraction analysis confirms its crystalline nature. The functional groups present in the crystal are identified by Fourier transform infrared spectroscopy. Elemental analysis confirms the stoichiometry of the elements present in the complex. Thermogravimetric analysis and differential thermal analysis reveal its good thermal stability. The optical properties like band gap, refractive index and extinction coefficient are evaluated from the UV-visible spectral analysis. The singular property of the material, corrosion inhibition efficiency achieved by the adsorption of the sample molecules is determined by the weight loss method.

Fine-Filament MgB2 Superconductor Wire

NASA Technical Reports Server (NTRS)

Cantu, Sherrie

2015-01-01

Hyper Tech Research, Inc., has developed fine-filament magnesium diboride (MgB2) superconductor wire for motors and generators used in turboelectric aircraft propulsion systems. In Phase I of the project, Hyper Tech demonstrated that MgB2 multifilament wires (<10 micrometers) could reduce alternating current (AC) losses that occur due to hysteresis, eddy currents, and coupling losses. The company refined a manufacturing method that incorporates a magnesium-infiltration process and provides a tenfold enhancement in critical current density over wire made by a conventional method involving magnesium-boron powder mixtures. Hyper Tech also improved its wire-drawing capability to fabricate fine multifilament strands. In Phase II, the company developed, manufactured, and tested the wire for superconductor and engineering current density and AC losses. Hyper Tech also fabricated MgB2 rotor coil packs for a superconducting generator. The ultimate goal is to enable low-cost, round, lightweight, low-AC-loss superconductors for motor and generator stator coils operating at 25 K in next-generation turboelectric aircraft propulsion systems.

Suborbital missions: The Joust

NASA Technical Reports Server (NTRS)

Ferguson, Bruce W.

1991-01-01

Joust 1 will carry a payload of 10 experiments. The experiments in the payload module will be mated with a service module containing accelerometers, avionics, a low gravity rate control system, and battery packs. This suborbital mission will last approximately 21 minutes, providing at least 13 minutes of microgravity time. The experiments are as follow: study into polymer membrane processes; polymer curing; plasma particle generation; automated generic bioprocessing apparatus; biomodule; thin films; materials dispersion apparatus; foam formation; electrodeposition process; and powdered materials processing.

Australian Defence Force Requirements for a Group-feeding Ration Pack

DTIC Science & Technology

2010-04-01

items were instant noodles and pasta (20% and 18% of respondents, respectively). 3.1.6 Items Commonly Discarded Beef and Pasta, Fruit Pudding...sheet). Although not usually required, there is provision to supplement the CR5M with a cereal adjunct such as bread, rice, pasta or noodles [6]. It is...of all the drink items. The Chocolate Drink Powder had the highest acceptability; its consumption was second to that of the Instant Coffee. The

Electromagnetic Metrology on Concrete and Corrosion.

PubMed

Kim, Sung; Surek, Jack; Baker-Jarvis, James

2011-01-01

To augment current methods for the evaluation of reinforcing bar (rebar) corrosion within concrete, we are exploring unique features in the dielectric and magnetic spectra of pure iron oxides and corrosion samples. Any signature needs to be both prominent and consistent in order to identify corrosion within concrete bridge deck or other structures. In order to measure the permittivity and propagation loss through concrete as a function of temperature and humidity, we cut and carefully fitted samples from residential concrete into three different waveguides. We also poured and cured a mortar sample within a waveguide that was later measured after curing 30 days. These measurements were performed from 45 MHz to 12 GHz. Our concrete measurements showed that the coarse granite aggregate that occupied about half the sample volume reduced the electromagnetic propagation loss in comparison to mortar. We also packed ground corrosion samples and commercially available iron-oxide powders into a transmission-line waveguide and found that magnetite and corrosion sample spectra are similar, with a feature between 0.5 GHz and 2 GHz that may prove useful for quantifying corrosion. We also performed reflection (S 11) measurements at various corrosion surfaces and in loose powders from 45 MHz to 50 GHz. These results are a first step towards quantifying rebar corrosion in concrete.

Electromagnetic Metrology on Concrete and Corrosion*

PubMed Central

Kim, Sung; Surek, Jack; Baker-Jarvis, James

2011-01-01

To augment current methods for the evaluation of reinforcing bar (rebar) corrosion within concrete, we are exploring unique features in the dielectric and magnetic spectra of pure iron oxides and corrosion samples. Any signature needs to be both prominent and consistent in order to identify corrosion within concrete bridge deck or other structures. In order to measure the permittivity and propagation loss through concrete as a function of temperature and humidity, we cut and carefully fitted samples from residential concrete into three different waveguides. We also poured and cured a mortar sample within a waveguide that was later measured after curing 30 days. These measurements were performed from 45 MHz to 12 GHz. Our concrete measurements showed that the coarse granite aggregate that occupied about half the sample volume reduced the electromagnetic propagation loss in comparison to mortar. We also packed ground corrosion samples and commercially available iron-oxide powders into a transmission-line waveguide and found that magnetite and corrosion sample spectra are similar, with a feature between 0.5 GHz and 2 GHz that may prove useful for quantifying corrosion. We also performed reflection (S11) measurements at various corrosion surfaces and in loose powders from 45 MHz to 50 GHz. These results are a first step towards quantifying rebar corrosion in concrete. PMID:26989590

Mesostructural investigation of micron-sized glass particles during shear deformation - An experimental approach vs. DEM simulation

NASA Astrophysics Data System (ADS)

Torbahn, Lutz; Weuster, Alexander; Handl, Lisa; Schmidt, Volker; Kwade, Arno; Wolf, Dietrich E.

2017-06-01

The interdependency of structure and mechanical features of a cohesive powder packing is on current scientific focus and far from being well understood. Although the Discrete Element Method provides a well applicable and widely used tool to model powder behavior, non-trivial contact mechanics of micron-sized particles demand a sophisticated contact model. Here, a direct comparison between experiment and simulation on a particle level offers a proper approach for model validation. However, the simulation of a full scale shear-tester experiment with micron-sized particles, and hence, validating this simulation remains a challenge. We address this task by down scaling the experimental setup: A fully functional micro shear-tester was developed and implemented into an X-ray tomography device in order to visualize the sample on a bulk and particle level within small bulk volumes of the order of a few micro liter under well-defined consolidation. Using spherical micron-sized particles (30 μm), shear tests with a particle number accessible for simulations can be performed. Moreover, particle level analysis allows for a direct comparison of experimental and numerical results, e.g., regarding structural evolution. In this talk, we focus on density inhomogeneity and shear induced heterogeneity during compaction and shear deformation.

Natural occurrence of ochratoxin A contamination in commercial black and white pepper products.

PubMed

Jalili, M; Jinap, S; Radu, S

2010-10-01

The concentration of ochratoxin A (OTA) in 120 commercial pepper (84 pre-packed and 36 bulk samples), which consist of local and imported white and black pepper in powder and seed form in Malaysia were determined. The objective of the study was to investigate and compare OTA concentration in black pepper and white pepper being commercialized in Malaysia. Determination method was based on HPLC with fluorescence detection coupled with immunoaffinity column clean-up step. Mobile phase consisted of acetonitrile-water-acetic acid (49.5:49.5:1.0, v/v/v), and flow rate was 1 ml/min. The LOD was 0.02 ng/g, and the average recovery values of OTA ranged from 79.5 to 92.0% in black pepper and 81.2-90.3% in white pepper. A total of 57 samples (47.5%) were contaminated with OTA ranging from 0.15 to 13.58 ng/g. The results showed that there was a significant difference between type of pepper and brands. OTA concentration in black pepper was significantly higher than white pepper (p < 0.05). The highest concentration of ochratoxin, 13.58 ng/g, was detected in a sample of black pepper seed followed by 12.64 ng/g in a sample of black pepper powder, both were bulk samples purchased from open market.

CTEPP STANDARD OPERATING PROCEDURE FOR PACKING AND SHIPPING STUDY SAMPLES (SOP-3.11)

EPA Science Inventory

This SOP describes the methods for packing and shipping study samples. These methods are for packing and shipping biological and environmental samples. The methods have been tested and used in the previous pilot studies.

Effect of amylose, particle size & morphology on the functionality of starches of traditional rice cultivars.

PubMed

Bhat, Farhan Mohiuddin; Riar, Charanjit Singh

2016-11-01

The research was carried out to investigate the effect of starch powder particle size, morphology, amylose content and varietal effect on physicochemical, X-ray diffraction pattern, thermal and pasting characteristics. The results indicated that starches isolated from seven traditional rice cultivars of temperate region of India have possessed higher yield (82.47-86.83%) with lower degree of granule damage and higher level of starch crystallinity (36.55-39.15%). The water and oil binding capacities were observed to correlate positively with amylose content. The bulk density and color parameters of starches were found to have linked with starch powder particle size coupled with arrangement and morphology of the starch granules. The rice cultivars having smaller starch powder particle size indicated lowest degree of crystallinity. Morphological studies revealed that the starches with tightly packed granules had greater mean granular width, while granules with openly spaced granular morphology depicted the higher values for mean granular length. The peak height index (PHI) among different starches ranged from 1.01 to 2.57 whereas the gelatinization range varied from 10.66 to 10.88. Concluding, the differences in distributional pattern of starch granule size and shape and powder particle size indicated a significant effect on the functional properties of starch. Copyright © 2016 Elsevier B.V. All rights reserved.

Application of the powder of porous titanium carbide ceramics to a reusable adsorbent for environmental pollutants.

PubMed

Moriwaki, Hiroshi; Kitajima, Shiori; Shirai, Koji; Kiguchi, Kenji; Yamada, Osamu

2011-01-30

The aim of this study is to investigate the utilization of the powder of porous titanium carbide (TiC) ceramics as a novel adsorbent or a material for solid-phase extraction (SPE). The adsorption and elution of inorganic and organic pollutants, Pb(II), 2,4,6-trichlorophenol (TCP), perfluorooctane sulfonate (PFOS), and perfluorooctanoic acid (PFOA), to the material were evaluated. The cartridge packed with TiC ceramics powder was used for the extraction test of pollutants. The solution containing pollutants at 1.0 μg mL(-1) was passed through the TiC cartridge, and the substances were almost quantitatively removed. Furthermore, the pollutants retained in the cartridge were eluted with 3N HCl for Pb(II) and with methanol for organic pollutants. The recoveries of pollutants were over 80%. In addition, we used the TiC cartridge for the solid-phase extraction of water samples (500 mL each of the distilled water and the river water) by adding pollutants at determined concentrations. Every pollutant was adsorbed almost quantitatively, and eluted by 3N HCl or methanol. From these results, we concluded that the powder of porous TiC ceramics is a useful reusable adsorbent for the water cleanup and solid-phase extraction. Copyright © 2010 Elsevier B.V. All rights reserved.

Stored grain pack factors for wheat: comparison of three methods to field measurements

USDA-ARS?s Scientific Manuscript database

Storing grain in bulk storage units results in grain packing from overbearing pressure, which increases grain bulk density and storage-unit capacity. This study compared pack factors of hard red winter (HRW) wheat in vertical storage bins using different methods: the existing packing model (WPACKING...

Possible mechanism for drug retardation from glyceryl monostearate matrix system.

PubMed

Peh, K K; Wong, C F; Yuen, K H

2000-04-01

Lipophilicity was evaluated as a possible mechanism for drug retardation from a glyceryl monostearate matrix system. Lipophilicity of the glyceryl monostearate matrix system was studied using contact angle measurement of water droplets on the surface of compressed disks, extrudate ascension of water, and movement of water through a powder mixture packed in a high-performance liquid chromatographic (HPLC) column. Increase in glyceryl monostearate content resulted in an increase in water droplet contact angle, decrease in the rate of water ascending the extrudate, and increase in the pressure values as a function of flow rate of water moving through the powder mixture. These could be due to the increase in lipophilicity of the matrix, rendering the matrix less wettable. As a result, the rate of water penetration into the matrix decreased, and the drug release could be sustained.

Ni-Al phase transformation of dual layer coating prepared by pack cementation and electrodeposition

NASA Astrophysics Data System (ADS)

Afandi, A.; Sugiarti, E.; Ekaputra, R.; Sudiro, T.; Thosin, K. A. Z.

2018-03-01

In this work, Fe-Cr alloys were coated via Aluminum (Al) pack cementation, followed by Nickel (Ni) electrodeposition. The process of pack cementation was done with mixing powders of Al, Al203 and NH4Cl with weight percentage of 15%, 85%, and 5% respectively. To control successful Al diffusion to the substrate, pack cementation was conducted for 7 hours with two holding temperatures treatment at 400 °C for 4 hours, and 800 ° C hours for 2 hours. Subsequently, the electrodeposition of Ni was applied with the solution consisting of NiSO4, H3BO3, and NiCl2. The samples were placed in the cathode, and then dipped in the solutions, while Ni plate used as anode. Successfully the samples were coated by dual Al-Ni layers, the samples were slowly heat treated at 900 °C for 10 hours. The inter-diffusion of Al and Ni were characterized with SEM/EDX to investigate the distribution of the elements. Mechanical properties of the coated substrates were analyzed with Hardness Vickers (HV). It was found the hardness of the substrate increased significantly, from originally 255 HV to the 1177 HV after pack cementation. The hardness of the substrates has decreased to 641 HV after Ni plating, but subsequent heat treatment has been able to increase the hardness to 842 HV. This phenomenon can be correlated to the inward Al diffusion, and outward Fe, Cr diffusion. The formation of intermetallic compounds due to Al inward and Fe, Cr outward diffusion were discussed in details.

Solid state structural investigations of the bis(chalcone) compound with single crystal X-ray crystallography, DFT, gamma-ray spectroscopy and chemical spectroscopy methods

NASA Astrophysics Data System (ADS)

Yakalı, Gül; Biçer, Abdullah; Eke, Canel; Cin, Günseli Turgut

2018-04-01

A bis(chalcone), (2E,6E)-2,6-bis((E)-3phenylallidene)cyclohexanone, was characterized by 1H NMR, 13C NMR, FTIR, UV-Vis spectroscopy, gamma-ray spectroscopy and single crystal X- ray structural analysis. The optimized molecular structure of the compound is calculated using DFT/B3LYP with 6-31G (d,p) level. The calculated geometrical parameters are in good agreement with the experimental data obtained from our reported X-ray structure. The powder and single crystal compounds were gama-irradiated using clinical electron linear accelerator and 60Co gamma-ray source, respectively. Spectral studies (1H NMR, 13C NMR, FTIR and UV-Vis) of powder chalcone compound were also investigated before and after irradiation. Depending on the irradiation notable changes were observed in spectral features powder sample. Single crystal X-ray diffraction investigation shows that both unirradiated and irradiated single crystal samples crystallizes in a orthorhombic crystal system in the centrosymmetric space group Pbcn and exhibits an C-H..O intramolecular and intermolecular hydrogen bonds. The crystal packing is stabilised by strong intermolecular bifurcate C-H..O hydrogen bonds and π…π stacking interactions. The asymmetric unit of the title compound contains one-half of a molecule. The other half of the molecule is generated with (1-x,y,-3/2-z) symmetry operator. The molecule is almost planar due to having π conjugated system of chalcones. However, irradiated single crystal compound showed significant changes lattice parameters, crystal volume and density. According to results of gamma-ray spectroscopy, radioactive elements of powder compound which are 123Sb(n,g),124Sb,57Fe(g,p),56Mn, 55Mn(g,n), and 54Mn were determined using photoactivation analysis. However, the most intensive gamma-ray energy signals are 124Sb.

Material selection and assembly method of battery pack for compact electric vehicle

NASA Astrophysics Data System (ADS)

Lewchalermwong, N.; Masomtob, M.; Lailuck, V.; Charoenphonphanich, C.

2018-01-01

Battery packs become the key component in electric vehicles (EVs). The main costs of which are battery cells and assembling processes. The battery cell is indeed priced from battery manufacturers while the assembling cost is dependent on battery pack designs. Battery pack designers need overall cost as cheap as possible, but it still requires high performance and more safety. Material selection and assembly method as well as component design are very important to determine the cost-effectiveness of battery modules and battery packs. Therefore, this work presents Decision Matrix, which can aid in the decision-making process of component materials and assembly methods for a battery module design and a battery pack design. The aim of this study is to take the advantage of incorporating Architecture Analysis method into decision matrix methods by capturing best practices for conducting design architecture analysis in full account of key design components critical to ensure efficient and effective development of the designs. The methodology also considers the impacts of choice-alternatives along multiple dimensions. Various alternatives for materials and assembly techniques of battery pack are evaluated, and some sample costs are presented. Due to many components in the battery pack, only seven components which are positive busbar and Z busbar are represented in this paper for using decision matrix methods.

Nuclear valve manufacturer selects stainless forgings

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

None

1976-02-01

Forged type 316 stainless steel components for nuclear valves are described. Automatic plasma arc welding with powder filler alloys is employed for hardfacing. Seat ring forgings are surfaced four-at-a-time with Stellite No. 156 in a sequential manner to minimize heat input to the individual components. After cladding and machining, seat rings are welded into the valve body using a semiautomatic, hot-wire gas tungsten-arc process. Disc faces and guide slots are surfaced with Stellite No. 6. The valve stem is machined from 17-4PH forged bar stock in the H-1100 condition. The heat treatment is specified to minimize pitting under prolonged exposuremore » to wet packing. A 12 rms (0.3 $mu$m) surface finish minimizes tearing of the packing and subsequent leakage. The link and stem pin are SA 564 Grade 660 (in the H-1100 condition) and ASTM A637 Grade 718 respectively. (JRD)« less

One-pot green synthesis of zinc oxide nano rice and its application as sonocatalyst for degradation of organic dye and synthesis of 2-benzimidazole derivatives

NASA Astrophysics Data System (ADS)

Paul, Bappi; Vadivel, Sethumathavan; Dhar, Siddhartha Sankar; Debbarma, Shyama; Kumaravel, M.

2017-05-01

In this paper, we report novel and green approach for one-pot biosynthesis of zinc oxide (ZnO) nanoparticles (NPs). Highly stable and hexagonal phase ZnO nanoparticles were synthesized using seeds extract from the tender pods of Parkia roxburghii and characterized by XRD, FT-IR, EDX, TEM, and N2 adsorption-desorption (BET) studies. The present method of synthesis of ZnO NPs is very efficient and cost effective. The powder XRD pattern furnished evidence for the formation of hexagonal close packing structure of ZnO NPs having average crystallite size 25.6 nm. The TEM image reveals rice shapes ZnO NPs are with an average diameter of 40-60 nm. The as-synthesized ZnO NPs has proved to be an excellent sonocatalysts for degradation of organic dye and synthesis of 2-benzimidazole derivatives.

Silver nanocluster catalytic microreactors for water purification

NASA Astrophysics Data System (ADS)

Da Silva, B.; Habibi, M.; Ognier, S.; Schelcher, G.; Mostafavi-Amjad, J.; Khalesifard, H. R. M.; Tatoulian, M.; Bonn, D.

2016-07-01

A new method for the elaboration of a novel type of catalytic microsystem with a high specific area catalyst is developed. A silver nanocluster catalytic microreactor was elaborated by doping a soda-lime glass with a silver salt. By applying a high power laser beam to the glass, silver nanoclusters are obtained at one of the surfaces which were characterized by BET measurements and AFM. A microfluidic chip was obtained by sealing the silver coated glass with a NOA 81 microchannel. The catalytic activity of the silver nanoclusters was then tested for the efficiency of water purification by using catalytic ozonation to oxidize an organic pollutant. The silver nanoclusters were found to be very stable in the microreactor and efficiently oxidized the pollutant, in spite of the very short residence times in the microchannel. This opens the way to study catalytic reactions in microchannels without the need of introducing the catalyst as a powder or manufacturing complex packed bed microreactors.

Influence of dry cohesion on the micro- and macro-mechanical properties of dense polydisperse powders & grains

NASA Astrophysics Data System (ADS)

Kievitsbosch, Robert; Smit, Hendrik; Magnanimo, Vanessa; Luding, Stefan; Taghizadeh, Kianoosh

2017-06-01

Understanding how cohesive granular materials behave is of interest for many industrial applications, such as pharmaceutical or food and civil engineering. Models of the behaviour of granular materials on the microscopic scale can be used to obtain macroscopic continuum relations by a micro-macro transition approach. The Discrete Element Method (DEM) is used to inspect the influence of cohesion on the micro and macro behaviour of granular assemblies by using an elasto-plastic cohesive contact model. Interestingly, we observe that frictional samples prepared with different cohesion values show a significant difference in pressure and coordination number in the jammed regime; the differences become more pronounced when packings are closer to the jamming density, i.e. the lowest density where the system is mechanically stable. Furthermore, we observe that cohesion has an influence on the jamming density for frictional samples, but there is no influence on the jamming density for frictionless samples.

Spectroscopy of Loose and Cemented Sulfate-Bearing Soils: Implications for Duricrust on Mars

NASA Astrophysics Data System (ADS)

Cooper, Christopher D.; Mustard, John F.

2002-07-01

The goal of this work is to determine the spectroscopic properties of sulfate in martian soil analogs over the wavelength range 0.3 to 25 μm (which is relevant to existing and planned remotely sensed data sets for Mars). Sulfate is an abundant component of martian soil (up to 9% SO 3 by weight) and apparently exists as a particulate in the soil but also as a cement. Although previous studies have addressed the spectroscopic identity of sulfates on Mars, none have used laboratory mixtures of materials with sulfates at the abundances measured by landed spacecraft, nor have any works considered the effect of salt-cementation on spectral properties of soil materials. For this work we created mixtures of a palagonitic soil (JSC Mars-1) and sulfates (MgSO 4 and CaSO 4·2H 2O). The effects of cementation were determined and separated from the effects of packing and hydration by measuring the samples as loose powders, packed powders, cemented materials, and disaggregated materials. The results show that the presence of particulate sulfate is best observed in the 4-5 μm region. Soils cemented with sulfate exhibit a pronounced restrahlen band between 8 and 9 μm as well as well-defined absorptions in the 4-5 μm region. Cementation effects are distinct from packing effects and disaggregation of cemented samples rapidly diminishes the strength of the restrahlen bands. The results of this study show that sulfate in loose materials is more detectable in the near infrared (4-5 μm) than in the thermal infrared (8-9 μm). However, cemented materials are easily distinguished from loose mixtures in the thermal infrared because of the high values of their absorption coefficient in this region. Together these results suggest that both wavelength regions are important for determining the spatial extent and physical form of sulfates on the surface of Mars.

Blending Gelators to Tune Gel Structure and Probe Anion-Induced Disassembly

PubMed Central

Foster, Jonathan A; Edkins, Robert M; Cameron, Gary J; Colgin, Neil; Fucke, Katharina; Ridgeway, Sam; Crawford, Andrew G; Marder, Todd B; Beeby, Andrew; Cobb, Steven L; Steed, Jonathan W

2014-01-01

Blending different low molecular weight gelators (LMWGs) provides a convenient route to tune the properties of a gel and incorporate functionalities such as fluorescence. Blending a series of gelators having a common bis-urea motif, and functionalised with different amino acid-derived end-groups and differing length alkylene spacers is reported. Fluorescent gelators incorporating 1-and 2-pyrenyl moieties provide a probe of the mixed systems alongside structural and morphological data from powder diffraction and electron microscopy. Characterisation of the individual gelators reveals that although the expected α-urea tape motif is preserved, there is considerable variation in the gelation properties, molecular packing, fibre morphology and rheological behaviour. Mixing of the gelators revealed examples in which: 1) the gels formed separate, orthogonal networks maintaining their own packing and morphology, 2) the gels blended together into a single network, either adopting the packing and morphology of one gelator, or 3) a new structure not seen for either of the gelators individually was created. The strong binding of the urea functionalities to anions was exploited as a means of breaking down the gel structure, and the use of fluorescent gel blends provides new insights into anion-mediated gel dissolution. PMID:24302604

Effect of packing method on the randomness of disc packings

NASA Astrophysics Data System (ADS)

Zhang, Z. P.; Yu, A. B.; Oakeshott, R. B. S.

1996-06-01

The randomness of disc packings, generated by random sequential adsorption (RSA), random packing under gravity (RPG) and Mason packing (MP) which gives a packing density close to that of the RSA packing, has been analysed, based on the Delaunay tessellation, and is evaluated at two levels, i.e. the randomness at individual subunit level which relates to the construction of a triangle from a given edge length distribution and the randomness at network level which relates to the connection between triangles from a given triangle frequency distribution. The Delaunay tessellation itself is also analysed and its almost perfect randomness at the two levels is demonstrated, which verifies the proposed approach and provides a random reference system for the present analysis. It is found that (i) the construction of a triangle subunit is not random for the RSA, MP and RPG packings, with the degree of randomness decreasing from the RSA to MP and then to RPG packing; (ii) the connection of triangular subunits in the network is almost perfectly random for the RSA packing, acceptable for the MP packing and not good for the RPG packing. Packing method is an important factor governing the randomness of disc packings.

A novel approach of battery pack state of health estimation using artificial intelligence optimization algorithm

NASA Astrophysics Data System (ADS)

Zhang, Xu; Wang, Yujie; Liu, Chang; Chen, Zonghai

2018-02-01

An accurate battery pack state of health (SOH) estimation is important to characterize the dynamic responses of battery pack and ensure the battery work with safety and reliability. However, the different performances in battery discharge/charge characteristics and working conditions in battery pack make the battery pack SOH estimation difficult. In this paper, the battery pack SOH is defined as the change of battery pack maximum energy storage. It contains all the cells' information including battery capacity, the relationship between state of charge (SOC) and open circuit voltage (OCV), and battery inconsistency. To predict the battery pack SOH, the method of particle swarm optimization-genetic algorithm is applied in battery pack model parameters identification. Based on the results, a particle filter is employed in battery SOC and OCV estimation to avoid the noise influence occurring in battery terminal voltage measurement and current drift. Moreover, a recursive least square method is used to update cells' capacity. Finally, the proposed method is verified by the profiles of New European Driving Cycle and dynamic test profiles. The experimental results indicate that the proposed method can estimate the battery states with high accuracy for actual operation. In addition, the factors affecting the change of SOH is analyzed.

Review of the Methods for Production of Spherical Ti and Ti Alloy Powder

NASA Astrophysics Data System (ADS)

Sun, Pei; Fang, Zhigang Zak; Zhang, Ying; Xia, Yang

2017-10-01

Spherical titanium alloy powder is an important raw material for near-net-shape fabrication via a powder metallurgy (PM) manufacturing route, as well as feedstock for powder injection molding, and additive manufacturing (AM). Nevertheless, the cost of Ti powder including spherical Ti alloy has been a major hurdle that prevented PM Ti from being adopted for a wide range of applications. Especially with the increasing importance of powder-bed based AM technologies, the demand for spherical Ti powder has brought renewed attention on properties and cost, as well as on powder-producing processes. The performance of Ti components manufactured from powder has a strong dependence on the quality of powder, and it is therefore crucial to understand the properties and production methods of powder. This article aims to provide a cursory review of the basic techniques of commercial and emerging methods for making spherical Ti powder. The advantages as well as limitations of different methods are discussed.

Powder-based adsorbents having high adsorption capacities for recovering dissolved metals and methods thereof

DOEpatents

Janke, Christopher J.; Dai, Sheng; Oyola, Yatsandra

2016-05-03

A powder-based adsorbent and a related method of manufacture are provided. The powder-based adsorbent includes polymer powder with grafted side chains and an increased surface area per unit weight to increase the adsorption of dissolved metals, for example uranium, from aqueous solutions. A method for forming the powder-based adsorbent includes irradiating polymer powder, grafting with polymerizable reactive monomers, reacting with hydroxylamine, and conditioning with an alkaline solution. Powder-based adsorbents formed according to the present method demonstrated a significantly improved uranium adsorption capacity per unit weight over existing adsorbents.

Solid state ¹³C-NMR, infrared, X-ray powder diffraction and differential thermal studies of the homologous series of some mono-valent metal (Li, Na, K, Ag) n-alkanoates: a comparative study.

PubMed

Nelson, Peter N; Ellis, Henry A; White, Nicole A S

2015-06-15

A comparative study of the molecular packing, lattice structures and phase behaviors of the homologous series of some mono-valent metal carboxylates (Li, Na, K and Ag) is carried out via solid state FT-infrared and (13)C-NMR spectroscopes, X-rays powder diffraction, density measurements, differential scanning calorimetry, polarizing light microscopy and variable temperature infrared spectroscopy. It is proposed that, for lithium, sodium and potassium carboxylates, metal-carboxyl coordination is via asymmetric chelating bidentate bonding with extensive intermolecular interactions to form tetrahedral metal centers, irrespective of chain length. However, for silver n-alkanoates, carboxyl moieties are bound to silver ions via syn-syn type bridging bidentate coordination to form dimeric units held together by extensive head group inter-molecular interactions. Furthermore, the fully extended hydrocarbon chains which are crystallized in the all-trans conformation are tilted at ca. 30°, 27°, 15° and 31° with respect to a normal to the metal plane, for lithium, sodium, silver and potassium carboxylates, respectively. All compounds are packed as lamellar bilayer structures, however, lithium compounds are crystallized in a triclinic crystal system whilst silver, sodium and potassium n-alkanoates are all monoclinic with possible P1 bravais lattice. Odd-even alternation observed in various physical features is associated with different inter-planar spacing between closely packed layers in the bilayer which are not in the same plane; a phenomenon controlled by lattice packing symmetry requirements. All compounds, except silver carboxylates, show partially reversibly first order pre-melting transitions; the number of which increases with increasing chain length. These transitions are associated, for the most part, with lamellar collapse followed by increased gauche-trans isomerism in the methylene group assembly, irrespective of chain length. It is proposed that the absence of mesomorphic transitions in their phase sequences is due to a lack of sufficient balance between attractive and repulsive electrostatic and van der Waals forces during phase change. The evidence presented in this study shows that phase behaviors of mono-valent metal carboxylates are controlled, mainly, by head group bonding. Copyright © 2015 Elsevier B.V. All rights reserved.

Gas atomized precursor alloy powder for oxide dispersion strengthened ferritic stainless steel

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

Rieken, Joel

Gas atomization reaction synthesis (GARS) was employed as a simplified method for producing precursor powders for oxide dispersion strengthened (ODS) ferritic stainless steels (e.g., Fe-Cr-Y-(Ti,Hf)-O), departing from the conventional mechanical alloying (MA) process. During GARS processing a reactive atomization gas (i.e., Ar-O 2) was used to oxidize the powder surfaces during primary break-up and rapid solidification of the molten alloy. This resulted in envelopment of the powders by an ultra-thin (t < 150 nm) metastable Cr-enriched oxide layer that was used as a vehicle for solid-state transport of O into the consolidated microstructure. In an attempt to better understand themore » kinetics of this GARS reaction, theoretical cooling curves for the atomized droplets were calculated and used to establish an oxidation model for this process. Subsequent elevated temperature heat treatments, which were derived from Rhines pack measurements using an internal oxidation model, were used to promote thermodynamically driven O exchange reactions between trapped films of the initial Cr-enriched surface oxide and internal Y-enriched intermetallic precipitates. This novel microstructural evolution process resulted in the successful formation of nano-metric Y-enriched dispersoids, as confirmed using high energy X-ray diffraction and transmission electron microscopy (TEM), equivalent to conventional ODS alloys from MA powders. The thermal stability of these Y-enriched dispersoids was evaluated using high temperature (1200°C) annealing treatments ranging from 2.5 to 1,000 hrs of exposure. In a further departure from current ODS practice, replacing Ti with additions of Hf appeared to improve the Y-enriched dispersoid thermal stability by means of crystal structure modification. Additionally, the spatial distribution of the dispersoids was found to depend strongly on the original rapidly solidified microstructure. To exploit this, ODS microstructures were engineered from different powder particle size ranges, illustrating microstructural control as a function of particle solidification rate. The consolidation of ultra-fine powders (dia. ≤ 5μm) resulted in a significant reduction in dispersoid size and spacing, consistent with initial scanning electron microscopy studies on as-atomized cross-sectioned particles that suggested that these powders solidified above the threshold velocity to effectively solute trap Y within the α-(Fe,Cr) matrix. Interestingly, when the solidification velocity as a function of particle size was extracted from the aforementioned theoretical particle cooling curves, it could be offered as supporting evidence for these microstructure observations. Thermal-mechanical treatments also were used to create and evaluate the stability of a dislocation substructure within these alloys, using microhardness and TEM analysis of the alloy sub-grain and grain structure. Moreover, elevated temperature tensile tests up to 800°C were used to assess the initial mechanical strength of the ODS microstructure.« less

Phase Stability of a Powder Metallurgy Disk Superalloy

NASA Technical Reports Server (NTRS)

Gabb, Timothy P.; Gayda, John; Kantzos, P.; Telesman, Jack; Gang, Anita

2006-01-01

Advanced powder metallurgy superalloy disks in aerospace turbine engines now entering service can be exposed to temperatures approaching 700 C, higher than those previously encountered. They also have higher levels of refractory elements, which can increase mechanical properties at these temperatures but can also encourage phase instabilities during service. Microstructural changes including precipitation of topological close pack phase precipitation and coarsening of existing gamma' precipitates can be slow at these temperatures, yet potentially significant for anticipated disk service times exceeding 1,000 h. The ability to quantify and predict such potential phase instabilities and degradation of capabilities is needed to insure structural integrity and air worthiness of propulsion systems over the full life cycle. A prototypical advanced disk superalloy was subjected to high temperature exposures, and then evaluated. Microstructural changes and corresponding changes in mechanical properties were quantified. The results will be compared to predictions of microstructure modeling software.

Food powders flowability characterization: theory, methods, and applications.

PubMed

Juliano, Pablo; Barbosa-Cánovas, Gustavo V

2010-01-01

Characterization of food powders flowability is required for predicting powder flow from hoppers in small-scale systems such as vending machines or at the industrial scale from storage silos or bins dispensing into powder mixing systems or packaging machines. This review covers conventional and new methods used to measure flowability in food powders. The method developed by Jenike (1964) for determining hopper outlet diameter and hopper angle has become a standard for the design of bins and is regarded as a standard method to characterize flowability. Moreover, there are a number of shear cells that can be used to determine failure properties defined by Jenike's theory. Other classic methods (compression, angle of repose) and nonconventional methods (Hall flowmeter, Johanson Indicizer, Hosokawa powder tester, tensile strength tester, powder rheometer), used mainly for the characterization of food powder cohesiveness, are described. The effect of some factors preventing flow, such as water content, temperature, time consolidation, particle composition and size distribution, is summarized for the characterization of specific food powders with conventional and other methods. Whereas time-consuming standard methods established for hopper design provide flow properties, there is yet little comparative evidence demonstrating that other rapid methods may provide similar flow prediction.

Systems for column-based separations, methods of forming packed columns, and methods of purifying sample components

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2000-01-01

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2006-02-21

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Systems For Column-Based Separations, Methods Of Forming Packed Columns, And Methods Of Purifying Sample Components.

DOEpatents

Egorov, Oleg B.; O'Hara, Matthew J.; Grate, Jay W.; Chandler, Darrell P.; Brockman, Fred J.; Bruckner-Lea, Cynthia J.

2004-08-24

The invention encompasses systems for column-based separations, methods of packing and unpacking columns and methods of separating components of samples. In one aspect, the invention includes a method of packing and unpacking a column chamber, comprising: a) packing a matrix material within a column chamber to form a packed column; and b) after the packing, unpacking the matrix material from the column chamber without moving the column chamber. In another aspect, the invention includes a system for column-based separations, comprising: a) a fluid passageway, the fluid passageway comprising a column chamber and a flow path in fluid communication with the column chamber, the flow path being obstructed by a retaining material permeable to a carrier fluid and impermeable to a column matrix material suspended in the carrier fluid, the flow path extending through the column chamber and through the retaining material, the flow path being configured to form a packed column within the column chamber when a suspension of the fluid and the column matrix material is flowed along the flow path; and b) the fluid passageway extending through a valve intermediate the column chamber and the retaining material.

Lallemantia reylenne seeds as superdisintegrant: Formulation and evaluation of nimesulide orodispersible tablets

PubMed Central

Malik, Karan; Arora, Gurpreet; Singh, Inderbir; Arora, Sandeep

2011-01-01

Aim: Orodispersible tablets also known as fast dissolving tablets disintegrate instantaneously within the mouth and thus can be consumed without water. The present study was aimed to formulate orodispersible tablets of nimesulide by using Lallemantia reylenne seeds as natural superdisintegrant. Materials and Methods: Powdered lallemantia seeds were characterized for powder flow properties (bulk density, tapped density, carr's consolidation index, hausner ratio, angle of repose), swelling index, viscosity, pH, and loss on drying. The prepared tablets were evaluated for different tablet parametric tests, wetting time, water absorption ratio, effective pore radius, porosity, packing fraction, in vitro and in vivo disintegration time, in vitro dissolution and stability studies. Results and Discussion: Increase in Lallementia reylenne concentration had an appreciable effect on tablet hardness and friability which clearly indicated binding potential of the seeds. Water absorption ratio increased with increase in Lallemantia reylenne concentration from batch A1 to A4. Water uptake coupled natural polymer swelling could be the most probable mechanism for concentration dependent reduction in disintegration time by the Lallemantia reylenne seeds. Porosity of the formulated tablets was found to increase from batch A1-A4. The in vitro disintegration results were in line with in vivo disintegration results. Conclusion: It could be concluded that Lallemantia reylenne seeds could be used as natural superdisintegrant in the formulation of orodispersible tablets. PMID:23071942

A Method of Assembling Compact Coherent Fiber-Optic Bundles

NASA Technical Reports Server (NTRS)

Martin, Stefan; Liu, Duncan; Levine, Bruce Martin; Shao, Michael; Wallace, James

2007-01-01

A method of assembling coherent fiber-optic bundles in which all the fibers are packed together as closely as possible is undergoing development. The method is based, straightforwardly, on the established concept of hexagonal close packing; hence, the development efforts are focused on fixtures and techniques for practical implementation of hexagonal close packing of parallel optical fibers.

Impact Melting of Ordinary Chondrite Regoliths and the Production of Fine-grained Fe(sup 0)

NASA Technical Reports Server (NTRS)

Hoerz, Friedrich; Cintala, Mark J.; See, Thomas H.

2003-01-01

The detailed study of individual lunar soil grains provides evidence that the major optical properties of the lunar surface are primarily related to the production of fine-grained (< 20 nm, super-paramagnetic) Fe-particles in agglutinitic impact melts and to iron-rich vapor deposits on the surfaces of individual grains. These Fe-rich materials are derived from oxidized species due to high post-shock temperatures in the presence of solar-wind derived H2; part of the Fe-rich grain surfaces may also be due to sputtering processes. Identical processes were recently suggested for the optical maturation of S-type asteroid surfaces, the parent objects of ordinary chondrites (OCs). OCs, however, do not contain impact-produced soil melts, and should thus also be devoid of impact-triggered vapor condensates. The seeming disparity can only be understood if all OCs resemble relatively immature impact debris, akin to numerous lunar highland breccias. It is possible to assess this scenario by evaluating experimentally whether impact velocities of 5- 6 km/s, typical for the present day asteroid belt, suffice to produce both impact melts and fine-grained metallic iron. We used 125-250 m powders of the L6 chondrite ALH85017. These powders were aliquots from fines that were produced by collisionally disrupting a single, large (461g) chunk of this meteorite during nine impacts and by subjecting the resulting rubble to an additional 50 impacts. As a consequence, the present shock-recovery experiments employ target materials of exceptional fidelity (i.e., a real chondrite that was impact pulverized). The target powders were packed into tungsten-alloy containers to allow for the potential investigation of freshly produced, fine-grained iron and impacted by stainless-steel and tungsten flyer plates; the packing density varied between 38 and 45% porosity. Peak pressures ranged from 14.5 to 67 GPa and were attained after multiple reverberations of the shock wave at the interface of the silicate powder and metal container. Pressures in the 50 to 70 GPa range should be fairly typical for asteroid impacts at approx. 5-6 km/s, yet we note that these pressures refer to those at the projectile/target interface only and that most crater ejecta on OC parent-bodies will have experienced much lower stresses.

Structural Characterization and Absolute Luminescence Efficiency Evaluation of Gd2O2S High Packing Density Ceramic Screens Doped with Tb3+ and Eu3+ for further Applications in Radiology

NASA Astrophysics Data System (ADS)

Dezi, Anna; Monachesi, Elenasophie; D'Ignazio, Michela; Scalise, Lorenzo; Montalto, Luigi; Paone, Nicola; Rinaldi, Daniele; Mengucci, Paolo; Loudos, George; Bakas, Athanasios; Michail, Christos; Valais, Ioannis; Fountzoula, Christine; Fountos, George; David, Stratos

2017-11-01

Rare earth activators are impurities added in the phosphor material to enhance probability of visible photon emission during the luminescence process. The main activators employed are rare earth trivalent ions such as Ce+3, Tb+3, Pr3+ and Eu+3. In this work, four terbium-activated Gd2O2S (GOS) powder screens with different thicknesses (1049 mg/cm2, 425.41 mg/cm2, 313 mg/cm2 and 187.36 mg/cm2) and one europium-activated GOS powder screen (232.18 mg/cm2) were studied to investigate possible applications for general radiology detectors. Results presented relevant differences in crystallinity between the GOS:Tb doped screens and GOS:Eu screens in respect to the dopant agent present. The AE (Absolute efficiency) was found to rise (i) with the increase of the X-ray tube voltage with the highest peaking at 110kVp and (ii) with the decrease of the thickness among the four GOS:Tb. Comparing similar thickness values, the europium-activated powder screen showed lower AE than the corresponding terbium-activated.

Resistance to densification, tensile strength and capsule-filling performance of some pharmaceutical diluents.

PubMed

Nikolakakis, I; Aragon, O B; Malamataris, S

1998-07-01

The purpose of this study was to compare some indicators of capsule-filling performance, as measured by tapped density under different conditions, and elucidate possible quantitative relationships between variation of capsule fill-weight (%CV) and gravitational and inter-particle forces (attractive or frictional) derived from measurements of particle size, true density, low compression and tensile strength. Five common pharmaceutical diluents (lactose, maize starch, talc, Emcocel and Avicel) were investigated and two capsule-filling methods (pouring powder and dosator nozzle) were employed. It was found that for the pouring-type method the appropriateness of Hausner's ratio (HR), Carr's compressibility index (CC%) and Kawakita's constant (alpha) as indicators of capsule fill-weight variation decreases in the order alpha > CC% > HR; the appropriateness of these indicators also decreases with increasing cylinder size and with impact velocity during tapping. For the dosator-type method the appropriateness of the indicators decreases in the order HR > CC% > alpha, the opposite of that for the pouring-type method; the appropriateness of the indicators increases with decreasing cylinder size and impact velocity. The relationship between %CV and the ratio of inter-particle attractive to gravitational forces calculated from measurements of particle size and true density (Fvdw/Wp) was more significant for the pouring-type capsule-filling method. For the dosator-type method a significant relationship (1% level) was found between %CV and the product of Fvdw/Wp and a function expressing the increase, with packing density (p(f)), in the ratio of frictional to attractive inter-particle forces derived from compression (P) and tensile-strength (T) testing, d(log(P/T))/d(p(f)). The value of tapped density in predictions of capsule-filling performance is affected by the testing conditions in a manner depending on the filling method applied. For the pouring-type method predictions can be based on the ratio of attractive (inter-particle) to gravitational forces, whereas for the dosator-type method the contribution of frictional and attractive forces should, because of packing density change, also be taken into account.

Young people's perceptions of cigarette packaging and plain packaging: an online survey.

PubMed

Moodie, Crawford; Ford, Allison; Mackintosh, Anne Marie; Hastings, Gerard

2012-01-01

In the United Kingdom, with most marketing channels prohibited, packaging is one of the few remaining ways that tobacco companies can promote their products. An online survey with young people aged 10-17 years (N = 658) was used to explore why youth choose cigarettes, perceptions of pack color, and perceptions of plain (nonbranded) cigarette packaging. Young people were also shown an image of 3 plain packs, which differed by shape and method of opening, and asked which they liked most and thought others their age would smoke. Price and what significant others smoke were key factors for choosing cigarettes, with packaging also an important influence. More than a third of the sample associated lighter pack color with weak tasting and less harmful cigarettes. Plain packs were rated negatively as were perceptions of plain pack users. One in 3 showed a preference for either a narrow "perfume type" plain pack or a plain "slide" pack that opened from the side, and 1 in 3 also thought that young people would smoke these packs. Packaging appears to both attract young people and mislead them about product strength and relative harm. Innovative pack construction (novel pack shape and method of opening) and the use of color are instrumental in these effects. The findings therefore suggest that any move to plain packaging should not only consider the benefits of removing branding (including color) but also of standardizing pack construction in terms of shape and method of opening.

Method to blend separator powders

DOEpatents

Guidotti, Ronald A.; Andazola, Arthur H.; Reinhardt, Frederick W.

2007-12-04

A method for making a blended powder mixture, whereby two or more powders are mixed in a container with a liquid selected from nitrogen or short-chain alcohols, where at least one of the powders has an angle of repose greater than approximately 50 degrees. The method is useful in preparing blended powders of Li halides and MgO for use in the preparation of thermal battery separators.

A Modified Cooling Method and Its Application in "Drosophila" Experiments

ERIC Educational Resources Information Center

Qu, Wen-hui; Zhu, Tong-bo; Yang, Da-Xiang

2015-01-01

Chilling is a cost-effective and safe method of immobilising flies in "Drosophila" experiments. However, should condensation form on the plate, it would be fatal to the flies. Here we describe a modified cooling method using reusable commercial ice pack(s) (ca. 400 ml, 2-3 cm tall) rather than crushed ice. The ice pack is covered with a…

How does increasingly plainer cigarette packaging influence adult smokers’ perceptions about brand image? An experimental study

PubMed Central

Wakefield, M A; Germain, D; Durkin, S J

2008-01-01

Background: Cigarette packaging is a key marketing strategy for promoting brand image. Plain packaging has been proposed to limit brand image, but tobacco companies would resist removal of branding design elements. Method: A 3 (brand types) × 4 (degree of plain packaging) between-subject experimental design was used, using an internet online method, to expose 813 adult Australian smokers to one randomly selected cigarette pack, after which respondents completed ratings of the pack. Results: Compared with current cigarette packs with full branding, cigarette packs that displayed progressively fewer branding design elements were perceived increasingly unfavourably in terms of smokers’ appraisals of the packs, the smokers who might smoke such packs, and the inferred experience of smoking a cigarette from these packs. For example, cardboard brown packs with the number of enclosed cigarettes displayed on the front of the pack and featuring only the brand name in small standard font at the bottom of the pack face were rated as significantly less attractive and popular than original branded packs. Smokers of these plain packs were rated as significantly less trendy/stylish, less sociable/outgoing and less mature than smokers of the original pack. Compared with original packs, smokers inferred that cigarettes from these plain packs would be less rich in tobacco, less satisfying and of lower quality tobacco. Conclusion: Plain packaging policies that remove most brand design elements are likely to be most successful in removing cigarette brand image associations. PMID:18827035

Packed bed carburization of tantalum and tantalum alloy

DOEpatents

Lopez, Peter C.; Rodriguez, Patrick J.; Pereyra, Ramiro A.

1999-01-01

Packed bed carburization of a tantalum or tantalum alloy object. A method for producing corrosion-resistant tantalum or tantalum alloy objects is described. The method includes the steps of placing the object in contact with a carburizing pack, heating the packed object in vacuum furnace to a temperature whereby carbon from the pack diffuses into the object forming grains with tantalum carbide along the grain boundaries, and etching the surface of the carburized object. This latter step removes tantalum carbides from the surface of the carburized tantalum object while leaving the tantalum carbide along the grain boundaries.

Packed bed carburization of tantalum and tantalum alloy

DOEpatents

Lopez, P.C.; Rodriguez, P.J.; Pereyra, R.A.

1999-06-29

Packed bed carburization of a tantalum or tantalum alloy object is disclosed. A method for producing corrosion-resistant tantalum or tantalum alloy objects is described. The method includes the steps of placing the object in contact with a carburizing pack, heating the packed object in vacuum furnace to a temperature whereby carbon from the pack diffuses into the object forming grains with tantalum carbide along the grain boundaries, and etching the surface of the carburized object. This latter step removes tantalum carbides from the surface of the carburized tantalum object while leaving the tantalum carbide along the grain boundaries. 4 figs.

Centrifugal sedimentation for selectively packing channels with silica microbeads in three-dimensional micro/nanofluidic devices.

PubMed

Gong, Maojun; Bohn, Paul W; Sweedler, Jonathan V

2009-03-01

Incorporation of nanofluidic elements into microfluidic channels is one approach for adding filtration and partition functionality to planar microfluidic devices, as well as providing enhanced biomolecular separations. Here we introduce a strategy to pack microfluidic channels with silica nanoparticles and microbeads, thereby indirectly producing functional nanostructures; the method allows selected channels to be packed, here demonstrated so that a separation channel is packed while keeping an injection channel unpacked. A nanocapillary array membrane is integrated between two patterned microfluidic channels that cross each other in vertically separated layers. The membrane serves both as a frit for bead packing and as a fluid communication conduit between microfluidic channels. Centrifugal force-assisted sedimentation is then used to selectively pack the microfluidic channels using an aqueous silica bead suspension loaded into the appropriate inlet reservoirs. This packing approach may be used to simultaneously pack multiple channels with silica microbeads having different sizes and surface properties. The chip design and packing method introduced here are suitable for packing silica particles in sizes ranging from nanometers to micrometers and allow rapid (approximately 10 min) packing with high quality. The liquid/analyte transport characteristics of these packed micro/nanofluidic devices have potential utility in a wide range of applications, including electroosmotic pumping, liquid chromatographic separations, and electrochromatography.

Impact of Packing and Processing Technique on Mechanical Properties of Acrylic Denture Base Materials

PubMed Central

Nejatian, Touraj; Sefat, Farshid; Johnson, Tony

2015-01-01

The fracture resistance of polymethylmethacrylate (PMMA) as the most popular denture base material is not satisfactory. Different factors can be involved in denture fracture. Among them, flexural fatigue and impact are the most common failure mechanisms of an acrylic denture base. It has been shown that there is a correlation between the static strength and fatigue life of composite resins. Therefore, the transverse strength of the denture base materials can be an important indicator of their service life. In order to improve the fracture resistance of PMMA, extensive studies have been carried out; however, only a few promising results were achieved, which are limited to some mechanical properties of PMMA at the cost of other properties. This study aimed at optimizing the packing and processing condition of heat-cured PMMA as a denture base resin in order to improve its biaxial flexural strength (BFS). The results showed that the plain type of resin with a powder/monomer ratio of 2.5:1 or less, packed conventionally and cured in a water bath for 2 h at 95 °C provides the highest BFS. Also, it was found that the performance of the dry heat processor is inconsistent with the number of flasks being loaded.

Denitrification of groundwater using PHBV blends in packed bed reactors and the microbial diversity.

PubMed

Chu, Libing; Wang, Jianlong

2016-07-01

In the present study, three kinds of biopolymers, PHBV, PHBV/starch and PHBV/bamboo powder (BP) blends were used as carbon source and biofilm carriers for denitrification in packed bed reactors to remove nitrate from groundwater. Results showed that a fast start-up was obtained in bioreactors filled with both PHBV/Starch and PHBV/BP blends without external inocula and it took more than 3 month for PHBV reactor to reach the same loading rate. The PHBV/BP packed reactor exhibited a better nitrate removal efficiency (87.4 ± 7.0%) and less adverse effects in nitrite accumulation and DOC release (below 0.5 mg NO2N L(-1) and 10.5 mg DOC L(-1) in the effluent) during stable operation. Pyrosequencing analysis demonstrated that bacteria belonging to genus Clostridium in phylum Firmicus, which play the primary role in degrading the biopolymers, are the most dominant (33-15% of the sequences). The predominant species in all samples is related to Clostridium crotonatovorans. All the identified 11 genera of denitrifying bacteria affiliated with phylum Proteobacteria and constituted 30-55% in the representative sequences. The PHBV/BP blend is economically attractive carbon source with good denitrification performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Japan Report, Science and Technology.

DTIC Science & Technology

1987-03-18

electromelting and desiliconizing method and the alkali melting method are conventional methods to manufacture zirconia powder . The former method is low...cost, but does not produce high purity zirconia powder . In contrast, the latter method produces high-strength and ultrafine zirconia powder , but is

Laminated composite of magnetic alloy powder and ceramic powder and process for making same

DOEpatents

Moorhead, Arthur J.; Kim, Hyoun-Ee

1999-01-01

A laminated composite structure of alternating metal powder layers, and layers formed of an inorganic bonding media powder, and a method for manufacturing same are discosed. The method includes the steps of assembling in a cavity alternating layers of a metal powder and an inorganic bonding media of a ceramic, glass, and glass-ceramic. Heat, with or without pressure, is applied to the alternating layers until the particles of the metal powder are sintered together and bonded into the laminated composite structure by the layers of sintered inorganic bonding media to form a strong composite structure. The method finds particular application in the manufacture of high performance magnets wherein the metal powder is a magnetic alloy powder.

Laminated composite of magnetic alloy powder and ceramic powder and process for making same

DOEpatents

Moorhead, A.J.; Kim, H.

1999-08-10

A laminated composite structure of alternating metal powder layers, and layers formed of an inorganic bonding media powder, and a method for manufacturing same are disclosed. The method includes the steps of assembling in a cavity alternating layers of a metal powder and an inorganic bonding media of a ceramic, glass, and glass-ceramic. Heat, with or without pressure, is applied to the alternating layers until the particles of the metal powder are sintered together and bonded into the laminated composite structure by the layers of sintered inorganic bonding media to form a strong composite structure. The method finds particular application in the manufacture of high performance magnets wherein the metal powder is a magnetic alloy powder. 9 figs.

Quasistatic packings of droplets in flat microfluidic channels

NASA Astrophysics Data System (ADS)

Kadivar, Erfan

2016-02-01

As observed in recent experiments, monodisperse droplets self-assemble spontaneously in different ordered packings. In this work, we present a numerical study of the droplet packings in the flat rectangular microfluidic channels. Employing the boundary element method, we numerically solve the Stokes equation in two-dimension and investigate the appearance of droplet packing and transition between one and two-row packings of monodisperse emulsion droplets. By calculating packing force applied on the droplet interface, we investigate the effect of flow rate, droplet size, and surface tension on the packing configurations of droplets and transition between different topological packings.

Condensation in Nanoporous Packed Beds.

PubMed

Ally, Javed; Molla, Shahnawaz; Mostowfi, Farshid

2016-05-10

In materials with tiny, nanometer-scale pores, liquid condensation is shifted from the bulk saturation pressure observed at larger scales. This effect is called capillary condensation and can block pores, which has major consequences in hydrocarbon production, as well as in fuel cells, catalysis, and powder adhesion. In this study, high pressure nanofluidic condensation studies are performed using propane and carbon dioxide in a colloidal crystal packed bed. Direct visualization allows the extent of condensation to be observed, as well as inference of the pore geometry from Bragg diffraction. We show experimentally that capillary condensation depends on pore geometry and wettability because these factors determine the shape of the menisci that coalesce when pore filling occurs, contrary to the typical assumption that all pore structures can be modeled as cylindrical and perfectly wetting. We also observe capillary condensation at higher pressures than has been done previously, which is important because many applications involving this phenomenon occur well above atmospheric pressure, and there is little, if any, experimental validation of capillary condensation at such pressures, particularly with direct visualization.

Electrolyte paste for molten carbonate fuel cells

DOEpatents

Bregoli, Lawrance J.; Pearson, Mark L.

1995-01-01

The electrolyte matrix and electrolyte reservoir plates in a molten carbonate fuel cell power plant stack are filled with electrolyte by applying a paste of dry electrolyte powder entrained in a dissipatable carrier to the reactant flow channels in the current collector plate. The stack plates are preformed and solidified to final operating condition so that they are self sustaining and can be disposed one atop the other to form the power plant stack. Packing the reactant flow channels with the electrolyte paste allows the use of thinner electrode plates, particularly on the anode side of the cells. The use of the packed electrolyte paste provides sufficient electrolyte to fill the matrix and to entrain excess electrolyte in the electrode plates, which also serve as excess electrolyte reservoirs. When the stack is heated up to operating temperatures, the electrolyte in the paste melts, the carrier vaporizes, or chemically decomposes, and the melted electrolyte is absorbed into the matrix and electrode plates.

Method and product for phosphosilicate slurry for use in dentistry and related bone cements

DOEpatents

Wagh, Arun S.; Primus, Carolyn

2006-08-01

The present invention is directed to magnesium phosphate ceramics and their methods of manufacture. The composition of the invention is produced by combining a mixture of a substantially dry powder component with a liquid component. The substantially dry powder component comprises a sparsely soluble oxide powder, an alkali metal phosphate powder, a sparsely soluble silicate powder, with the balance of the substantially dry powder component comprising at least one powder selected from the group consisting of bioactive powders, biocompatible powders, fluorescent powders, fluoride releasing powders, and radiopaque powders. The liquid component comprises a pH modifying agent, a monovalent alkali metal phosphate in aqueous solution, the balance of the liquid component being water. The use of calcined magnesium oxide as the oxide powder and hydroxylapatite as the bioactive powder produces a self-setting ceramic that is particularly suited for use in dental and orthopedic applications.

General advancing front packing algorithm for the discrete element method

NASA Astrophysics Data System (ADS)

Morfa, Carlos A. Recarey; Pérez Morales, Irvin Pablo; de Farias, Márcio Muniz; de Navarra, Eugenio Oñate Ibañez; Valera, Roberto Roselló; Casañas, Harold Díaz-Guzmán

2018-01-01

A generic formulation of a new method for packing particles is presented. It is based on a constructive advancing front method, and uses Monte Carlo techniques for the generation of particle dimensions. The method can be used to obtain virtual dense packings of particles with several geometrical shapes. It employs continuous, discrete, and empirical statistical distributions in order to generate the dimensions of particles. The packing algorithm is very flexible and allows alternatives for: 1—the direction of the advancing front (inwards or outwards), 2—the selection of the local advancing front, 3—the method for placing a mobile particle in contact with others, and 4—the overlap checks. The algorithm also allows obtaining highly porous media when it is slightly modified. The use of the algorithm to generate real particle packings from grain size distribution curves, in order to carry out engineering applications, is illustrated. Finally, basic applications of the algorithm, which prove its effectiveness in the generation of a large number of particles, are carried out.

Linking flowability and granulometry of lactose powders.

PubMed

Boschini, F; Delaval, V; Traina, K; Vandewalle, N; Lumay, G

2015-10-15

The flowing properties of 10 lactose powders commonly used in pharmaceutical industries have been analyzed with three recently improved measurement methods. The first method is based on the heap shape measurement. This straightforward measurement method provides two physical parameters (angle of repose αr and static cohesive index σr) allowing to make a first screening of the powder properties. The second method allows to estimate the rheological properties of a powder by analyzing the powder flow in a rotating drum. This more advanced method gives a large set of physical parameters (flowing angle αf, dynamic cohesive index σf, angle of first avalanche αa and powder aeration %ae) leading to deeper interpretations. The third method is an improvement of the classical bulk and tapped density measurements. In addition to the improvement of the measurement precision, the densification dynamics of the powder bulk submitted to taps is analyzed. The link between the macroscopic physical parameters obtained with these methods and the powder granulometry is analyzed. Moreover, the correlations between the different flowability indexes are discussed. Finally, the link between grain shape and flowability is discussed qualitatively. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimization analysis of thermal management system for electric vehicle battery pack

NASA Astrophysics Data System (ADS)

Gong, Huiqi; Zheng, Minxin; Jin, Peng; Feng, Dong

2018-04-01

Electric vehicle battery pack can increase the temperature to affect the power battery system cycle life, charge-ability, power, energy, security and reliability. The Computational Fluid Dynamics simulation and experiment of the charging and discharging process of the battery pack were carried out for the thermal management system of the battery pack under the continuous charging of the battery. The simulation result and the experimental data were used to verify the rationality of the Computational Fluid Dynamics calculation model. In view of the large temperature difference of the battery module in high temperature environment, three optimization methods of the existing thermal management system of the battery pack were put forward: adjusting the installation position of the fan, optimizing the arrangement of the battery pack and reducing the fan opening temperature threshold. The feasibility of the optimization method is proved by simulation and experiment of the thermal management system of the optimized battery pack.

White random lasing in mixture of ZnSe, CdS and CdSSe micropowders

NASA Astrophysics Data System (ADS)

Alyamani, A. Y.; Leanenia, M. S.; Alanazi, L. M.; Aljohani, M. M.; Aljariwi, A. A.; Rzheutski, M. V.; Lutsenko, E. V.; Yablonskii, G. P.

2016-03-01

Room temperature random lasing with white light emission in a mixture of AIIBVI semiconductor powders was achieved for the first time. The scattering gain media was formed by the mixture of closely packed active micron sized crystallites of ZnSe, CdS, CdSSe semiconductors. The micropowders were produced by grinding bulk crystals of each compound. Optical excitation was performed by 10-nanosecond pulses of tuned Ti:Al2O3-laser at 390 nm. The lasing in the mixture of semiconductor powders was achieved simultaneously at four wavelengths in blue, green, yellow and red spectral regions after exceeding the threshold excitation power density. A drastic integral intensity increase, spectrum narrowing and appearance of mode structure accompanied the laser action. ZnSe crystallites produce the laser light at about 460 nm while CdS particles - at about 520 nm. Two types of CdSSe semiconductor micropowders with different sulfur content lase at 580 nm and 660 nm. The threshold excitation power densities for all laser lines in the emission spectrum are approximately the same of about 0.9 MW/cm2. The sum of the emission spectrum of the mixture of the micropowders forms white light with high brightness. Lasing is due to an appearance of random feedback for amplified radiation in the active medium of closely packed light scattering crystallites. The presented results may find their applications for visualization systems, lighting technology, data transmission, medicine as biosensors and in identification systems. The key feature of random lasers is low cost of its production and possibility to be deposited on any type of surface.

[Hepatic hemostasis with packing in complex abdominal traumatic lesions: indications and postoperative outcomes].

PubMed

Mazilu, O; Cnejevici, S; Stef, D; Istodor, A; Dabelea, C; Fluture, V

2009-01-01

The purpose of this study is to review our postoperative outcomes with liver packing in complex abdominal trauma. 76 liver trauma were admitted for operative procedures in the Surgical Department of City Hospital Timisoara between April 1994 - September 2009 and 16 cases were identified in our series as requiring liver packing. In all cases, this method was efficient, with no postoperative bleeding. In the same time, there were specific complications such as bile leak or abdominal collections. despite a second procedure for packs removal and the possibility for specific complications, liver packing is an efficient method for severe liver trauma or complex abdominal lesions.

The Pack Method for Compressive Tests of Thin Specimens of Materials Used in Thin-Wall Structures

NASA Technical Reports Server (NTRS)

Aitchison, C S; Tuckerman, L B

1939-01-01

The strength of modern lightweight thin-wall structures is generally limited by the strength of the compression members. An adequate design of these members requires a knowledge of the compressive stress-strain graph of the thin-wall material. The "pack" method was developed at the National Bureau of Standards with the support of the National Advisory Committee for Aeronautics to make possible a determination of compressive stress-strain graphs for such material. In the pack test an odd number of specimens are assembled into a relatively stable pack, like a "pack of cards." Additional lateral stability is obtained from lateral supports between the external sheet faces of the pack and outside reactions. The tests seems adequate for many problems in structural research.

High-resolution direct 3D printed PLGA scaffolds: print and shrink.

PubMed

Chia, Helena N; Wu, Benjamin M

2014-12-17

Direct three-dimensional printing (3DP) produces the final part composed of the powder and binder used in fabrication. An advantage of direct 3DP is control over both the microarchitecture and macroarchitecture. Prints which use porogen incorporated in the powder result in high pore interconnectivity, uniform porosity, and defined pore size after leaching. The main limitations of direct 3DP for synthetic polymers are the use of organic solvents which can dissolve polymers used in most printheads and limited resolution due to unavoidable spreading of the binder droplet after contact with the powder. This study describes a materials processing strategy to eliminate the use of organic solvent during the printing process and to improve 3DP resolution by shrinking with a non-solvent plasticizer. Briefly, poly(lactic-co-glycolic acid) (PLGA) powder was prepared by emulsion solvent evaporation to form polymer microparticles. The printing powder was composed of polymer microparticles dry mixed with sucrose particles. After printing with a water-based liquid binder, the polymer microparticles were fused together to form a network by solvent vapor in an enclosed vessel. The sucrose is removed by leaching and the resulting scaffold is placed in a solution of methanol. The methanol acts as a non-solvent plasticizer and allows for polymer chain rearrangement and efficient packing of polymer chains. The resulting volumetric shrinkage is ∼80% at 90% methanol. A complex shape (honey-comb) was designed, printed, and shrunken to demonstrate isotropic shrinking with the ability to reach a final resolution of ∼400 μm. The effect of type of alcohol (i.e. methanol or ethanol), concentration of alcohol, and temperature on volumetric shrinking was studied. This study presents a novel materials processing strategy to overcome the main limitations of direct 3DP to produce high resolution PLGA scaffolds.

The Relationship Between the Permeability and the Performance of Carrier-Based Dry Powder Inhalation Mixtures: New Insights and Practical Guidance.

PubMed

Shalash, Ahmed O; Khalafallah, Nawal M; Molokhia, Abdulla M; Elsayed, Mustafa M A

2018-02-01

The permeability of a powder bed reflects its particle size distribution, shape, packing, porosity, cohesivity, and tensile strength in a manner relevant to powder fluidization. The relationship between the permeability and the performance of carrier-based dry powder inhalation (DPI) mixtures has, however, aroused controversy. The current study sought to gain new insights into the relationship and to explore its potential applications. We studied eight lactose materials as DPI carriers. The carriers covered a broad permeability range of 0.42-13.53 D and moreover differed in particle size distribution, particle shape, crystal form, and/or porosity. We evaluated the performance of inhalation mixtures of each of these carriers and fluticasone propionate after aerosolization from an Aerolizer®, a model turbulent-shear inhaler, at a flow rate of 60 L/min. Starting from the high permeability side, the inhalation mixture performance increased as the carrier permeability decreased until optimum performance was reached at permeability of ~ 3.2 D. Increased resistance to air flow strengthens aerodynamic dispersion forces. The inhalation mixture performance then decreased as the carrier permeability further decreased. Very high resistance to air flow restricts powder dispersion. The permeability accounted for effects of carrier size, shape, and macroporosity on the performance. We confirmed the relationship by analysis of two literature permeability-performance datasets, representing measurements that differ from ours in terms of carrier grades, drug, technique used to determine permeability, turbulent-shear inhaler, and/or aerosolization flow rate. Permeability provides useful information that can aid development of DPI mixtures for turbulent-shear inhalers. A practical guidance is provided.

Determination of whey adulteration in milk powder by using laser induced breakdown spectroscopy.

PubMed

Bilge, Gonca; Sezer, Banu; Eseller, Kemal Efe; Berberoglu, Halil; Topcu, Ali; Boyaci, Ismail Hakki

2016-12-01

A rapid and in situ method has been developed to detect and quantify adulterated milk powder through adding whey powder by using laser induced breakdown spectroscopy (LIBS). The methodology is based on elemental composition differences between milk and whey products. Milk powder, sweet and acid whey powders were produced as standard samples, and milk powder was adulterated with whey powders. Based on LIBS spectra of standard samples and commercial products, species was identified using principle component analysis (PCA) method, and discrimination rate of milk and whey powders was found as 80.5%. Calibration curves were obtained with partial least squares regression (PLS). Correlation coefficient (R(2)) and limit of detection (LOD) values were 0.981 and 1.55% for adulteration with sweet whey powder, and 0.985 and 0.55% for adulteration with acid whey powder, respectively. The results were found to be consistent with the data from inductively coupled plasma - mass spectrometer (ICP-MS) method. Copyright © 2016 Elsevier Ltd. All rights reserved.

Simultaneous quantification of paracetamol, acetylsalicylic acid and papaverine with a validated HPLC method.

PubMed

Kalmár, Eva; Gyuricza, Anett; Kunos-Tóth, Erika; Szakonyi, Gerda; Dombi, György

2014-01-01

Combined drug products have the advantages of better patient compliance and possible synergic effects. The simultaneous application of several active ingredients at a time is therefore frequently chosen. However, the quantitative analysis of such medicines can be challenging. The aim of this study is to provide a validated method for the investigation of a multidose packed oral powder that contained acetylsalicylic acid, paracetamol and papaverine-HCl. Reversed-phase high-pressure liquid chromatography was used. The Agilent Zorbax SB-C18 column was found to be the most suitable of the three different stationary phases tested for the separation of the components of this sample. The key parameters in the method development (apart from the nature of the column) were the pH of the aqueous phase (set to 3.4) and the ratio of the organic (acetonitrile) and the aqueous (25 mM phosphate buffer) phases, which was varied from 7:93 (v/v) to 25:75 (v/v) in a linear gradient, preceded by an initial hold. The method was validated: linearity, precision (repeatability and intermediate precision), accuracy, specificity and robustness were all tested, and the results met the ICH guidelines. © The Author [2013]. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Multigrid contact detection method

NASA Astrophysics Data System (ADS)

He, Kejing; Dong, Shoubin; Zhou, Zhaoyao

2007-03-01

Contact detection is a general problem of many physical simulations. This work presents a O(N) multigrid method for general contact detection problems (MGCD). The multigrid idea is integrated with contact detection problems. Both the time complexity and memory consumption of the MGCD are O(N) . Unlike other methods, whose efficiencies are influenced strongly by the object size distribution, the performance of MGCD is insensitive to the object size distribution. We compare the MGCD with the no binary search (NBS) method and the multilevel boxing method in three dimensions for both time complexity and memory consumption. For objects with similar size, the MGCD is as good as the NBS method, both of which outperform the multilevel boxing method regarding memory consumption. For objects with diverse size, the MGCD outperform both the NBS method and the multilevel boxing method. We use the MGCD to solve the contact detection problem for a granular simulation system based on the discrete element method. From this granular simulation, we get the density property of monosize packing and binary packing with size ratio equal to 10. The packing density for monosize particles is 0.636. For binary packing with size ratio equal to 10, when the number of small particles is 300 times as the number of big particles, the maximal packing density 0.824 is achieved.

NO removal by nonthermal plasma with modified sepiolite catalyst

NASA Astrophysics Data System (ADS)

Chen, M. G.; Yu, D. X.; Rong, J. F.; Wan, Y. L.; Li, G. C.; Ni, Y. M.; Fan, X.; Hou, G. H.; Xu, N.

2013-03-01

Non-Thermal Plasma (NTP) combined with a catalyst is one of the effective ways to remove NO from auto exhaust gas. Sepiolite Ore Powder (SOP), which was modified by acid washing, copper nitrate soaking, drying and calcinations, served as the Modified Sepiolite Catalyst (MSC) for NO removal in a rod-cylinder Dielectric Barrier Discharge (DBD) reactor. The characteristic of the MSC was characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The experiment showed that the acid concentration, washing time, the packed site of MSC and input voltage of the NTP impacted the NO removal rate effectively. The NO removal rate increased and then decreased with an increase in the acid concentration and the washing time, and the NO removal rate increased monotonously with the increased input voltage. The NO removal rate was higher at the beginning, decreased gradually then maintained stability after 10 min. Thus, the result indicated that MSC has a good ability for adsorption and storage of NO.

Use of Pom Pons to Illustrate Cubic Crystal Structures.

ERIC Educational Resources Information Center

Cady, Susan G.

1997-01-01

Describes a method that uses olefin pom pons to illustrate cubic crystal structure. Facilitates hands-on examination of different packing arrangements such as hexagonal close-packed and cubic close-packed structures. (JRH)

Methods and systems for combustion dynamics reduction

DOEpatents

Kraemer, Gilbert Otto [Greer, SC; Varatharajan, Balachandar [Cincinnati, OH; Srinivasan, Shiva [Greer, SC; Lynch, John Joseph [Wilmington, NC; Yilmaz, Ertan [Albany, NY; Kim, Kwanwoo [Greer, SC; Lacy, Benjamin [Greer, SC; Crothers, Sarah [Greenville, SC; Singh, Kapil Kumar [Rexford, NY

2009-08-25

Methods and systems for combustion dynamics reduction are provided. A combustion chamber may include a first premixer and a second premixer. Each premixer may include at least one fuel injector, at least one air inlet duct, and at least one vane pack for at least partially mixing the air from the air inlet duct or ducts and fuel from the fuel injector or injectors. Each vane pack may include a plurality of fuel orifices through which at least a portion of the fuel and at least a portion of the air may pass. The vane pack or packs of the first premixer may be positioned at a first axial position and the vane pack or packs of the second premixer may be positioned at a second axial position axially staggered with respect to the first axial position.

The impact of cigarette pack shape, size and opening: evidence from tobacco company documents.

PubMed

Kotnowski, Kathy; Hammond, David

2013-09-01

To use tobacco industry documents on cigarette pack shape, size and openings to identify industry findings on associations with brand imagery, product attributes, consumer perceptions and behaviour. Internal tobacco industry research and marketing documents obtained through court disclosure contained in the Legacy Tobacco Documents Library were searched using keywords related to pack shapes, sizes and opening methods. The search identified 66 documents related to consumer research and marketing plans on pack shape, size and openings, drawn from 1973 to 2002. Industry research consistently found that packs that deviated from the traditional flip-top box projected impressions of 'modern', 'elegant' and 'unique' brand imagery. Alternative pack shape and openings were identified as an effective means to communicate product attributes, particularly with regard to premium quality and smooth taste. Consumer studies consistently found that pack shape, size and opening style influenced perceptions of reduced product harm, and were often used to communicate a 'lighter' product. Slim, rounded, oval and booklet packs were found to be particularly appealing among young adults, and several studies demonstrated increased purchase interest for tobacco products presented in novel packaging shape or opening. Evidence from consumer tracking reports and company presentations indicate that pack innovations in shape or opening method increased market share of brands. Consumer research by the tobacco industry between 1973 and 2002 found that variations in packaging shape, size and opening method could influence brand appeal and risk perceptions and increase cigarette sales. © 2013 Society for the Study of Addiction.

The compression–error trade-off for large gridded data sets

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

Silver, Jeremy D.; Zender, Charles S.

The netCDF-4 format is widely used for large gridded scientific data sets and includes several compression methods: lossy linear scaling and the non-lossy deflate and shuffle algorithms. Many multidimensional geoscientific data sets exhibit considerable variation over one or several spatial dimensions (e.g., vertically) with less variation in the remaining dimensions (e.g., horizontally). On such data sets, linear scaling with a single pair of scale and offset parameters often entails considerable loss of precision. We introduce an alternative compression method called "layer-packing" that simultaneously exploits lossy linear scaling and lossless compression. Layer-packing stores arrays (instead of a scalar pair) of scalemore » and offset parameters. An implementation of this method is compared with lossless compression, storing data at fixed relative precision (bit-grooming) and scalar linear packing in terms of compression ratio, accuracy and speed. When viewed as a trade-off between compression and error, layer-packing yields similar results to bit-grooming (storing between 3 and 4 significant figures). Bit-grooming and layer-packing offer significantly better control of precision than scalar linear packing. Relative performance, in terms of compression and errors, of bit-groomed and layer-packed data were strongly predicted by the entropy of the exponent array, and lossless compression was well predicted by entropy of the original data array. Layer-packed data files must be "unpacked" to be readily usable. The compression and precision characteristics make layer-packing a competitive archive format for many scientific data sets.« less

The compression–error trade-off for large gridded data sets

DOE PAGES

Silver, Jeremy D.; Zender, Charles S.

2017-01-27

The netCDF-4 format is widely used for large gridded scientific data sets and includes several compression methods: lossy linear scaling and the non-lossy deflate and shuffle algorithms. Many multidimensional geoscientific data sets exhibit considerable variation over one or several spatial dimensions (e.g., vertically) with less variation in the remaining dimensions (e.g., horizontally). On such data sets, linear scaling with a single pair of scale and offset parameters often entails considerable loss of precision. We introduce an alternative compression method called "layer-packing" that simultaneously exploits lossy linear scaling and lossless compression. Layer-packing stores arrays (instead of a scalar pair) of scalemore » and offset parameters. An implementation of this method is compared with lossless compression, storing data at fixed relative precision (bit-grooming) and scalar linear packing in terms of compression ratio, accuracy and speed. When viewed as a trade-off between compression and error, layer-packing yields similar results to bit-grooming (storing between 3 and 4 significant figures). Bit-grooming and layer-packing offer significantly better control of precision than scalar linear packing. Relative performance, in terms of compression and errors, of bit-groomed and layer-packed data were strongly predicted by the entropy of the exponent array, and lossless compression was well predicted by entropy of the original data array. Layer-packed data files must be "unpacked" to be readily usable. The compression and precision characteristics make layer-packing a competitive archive format for many scientific data sets.« less

Shock induced crystallization of amorphous Nickel powders

NASA Astrophysics Data System (ADS)

Cherukara, Mathew; Strachan, Alejandro

2015-06-01

Recent experimental work has shown the efficacy of amorphous Ni/crystalline Al composites as energetic materials, with flame velocities twice that of a comparable crystalline Ni/crystalline Al system. Of further interest is the recrystallization mechanisms in the pure amorphous Ni powders, both thermally induced and mechanically induced. We present large-scale molecular dynamics simulations of shock-induced recrystallization in loosely packed amorphous Nickel powders. We study the time dependent nucleation and growth processes by holding the shocked samples at the induced pressures and temperatures for extended periods following the passage of the shock (up to 6 ns). We find that the nanostructure of the recrystallized Ni and time scales of recrystallization are dependent on the piston velocity. At low piston velocities, nucleation events are rare, leading to long incubation times and a relatively coarse nanostructure. At higher piston velocities, local variations in temperature due to jetting phenomena and void collapse, give rise to multiple nucleation events on time scales comparable to the passage of the shock wave, leading to the formation of a fine-grained nanostructure. Interestingly, we observe that the nucleation and growth process occurs in two steps, with the first nuclei crystallizing into the BCC structure, before evolving over time into the expected FCC structure. U.S. Defense Threat Reduction Agency, HDTRA1-10-1-0119 (Program Manager Suhithi Peiris).

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

Salud, J.; Lopez, D.O.; Barrio, M.

The experimental two-component phase diagram between the orientationally disordered crystals 2-amino-2-methyl-1,3-propanediol (AMP) and 1,1,1-tris(hydroxymethyl)propane (PG) has been established from room temperature to the liquid state using thermal analysis and X-ray powder diffraction techniques. The intermolecular interactions in the orientationally disordered mixed crystals of the mentioned system and other related two-component systems are discussed by analyzing the evolution of the packing coefficient as a function of the composition. A thermodynamic analysis of the presented phase diagram and the redetermined AMP/NPG (2,2-dimethyl-1,3-propanediol) is reported on the basis of the enthalpy-entropy compensation theory.

Air powder abrasive treatment as an implant surface cleaning method: a literature review.

PubMed

Tastepe, Ceylin S; van Waas, Rien; Liu, Yuelian; Wismeijer, Daniel

2012-01-01

To evaluate the air powder abrasive treatment as an implant surface cleaning method for peri-implantitis based on the existing literature. A PubMed search was conducted to find articles that reported on air powder abrasive treatment as an implant surface cleaning method for peri-implantitis. The studies evaluated cleaning efficiency and surface change as a result of the method. Furthermore, cell response toward the air powder abrasive-treated discs, reosseointegration, and clinical outcome after treatment is also reported. The PubMed search resulted in 27 articles meeting the inclusion criteria. In vitro cleaning efficiency of the method is reported to be high. The method resulted in minor surface changes on titanium specimens. Although the air powder abrasive-treated specimens showed sufficient levels of cell attachment and cell viability, the cell response decreased compared with sterile discs. Considerable reosseointegration between 39% and 46% and improved clinical parameters were reported after treatment when applied in combination with surgical treatment. The results of the treatment are influenced by the powder type used, the application time, and whether powder was applied surgically or nonsurgically. The in vivo data on air powder abrasive treatment as an implant surface cleaning method is not sufficient to draw definitive conclusions. However, in vitro results allow the clinician to consider the method as a promising option for implant surface cleaning in peri-implantitis treatment.

Structure disordering and thermal decomposition of manganese oxalate dihydrate, MnC2O4·2H2O

NASA Astrophysics Data System (ADS)

Puzan, Anna N.; Baumer, Vyacheslav N.; Lisovytskiy, Dmytro V.; Mateychenko, Pavel V.

2018-04-01

It is found that the known regular structures of MnC2O4·2H2O (I) do not allow to refine the powder X-ray pattern of (I) properly using the Rietveld method. Implementation of order-disorder scheme [28] via the including of appropriate displacement vector improves the refinement results. Also it is found that in the case of (I) the similar improvement may be achieved using the data on two phases of (I) obtained as result of decomposition MnC2O4·3H2O single crystal in the mother solution after growth. Thermal decomposition of (I) produce the anhydrous γ-MnC2O4 (II) the structure of which is differ from the known α- and β-modifications of VIIIb transition metal oxalates. The solved ab initio from the powder pattern structure (II) (space group Pmna, a = 7.1333 (1), b = 5.8787 (1), c = 9.0186 (2) Å, V = 378.19 (1) Å3, Z = 4 and Dx = 2.511 Mg m-3) contains seven-coordinated Mn atoms with Mn-O distances of 2.110-2.358 Å, and is not close-packed. Thermal decomposition of (II) in air flows via forming of amorphous MnO, the heating of which up to 723 K is accompanied by oxidation of MnO to Mn2O3 and further recrystallization of the latter.

Vacuum powder injector and method of impregnating fiber with powder

NASA Astrophysics Data System (ADS)

Working, Dennis C.

1993-05-01

A method and apparatus uniformly impregnate stranded material with dry powder such as low solubility, high melt flow polymer powder to produce, for example, composite prepregs. The stranded material is expanded in an impregnation chamber by an influx of air so that the powder, which may enter through the same inlet as the air, penetrates to the center of the stranded material. The stranded material then is contracted for holding the powder therein. The stranded material and powder may be pulled through the impregnation chamber in the same direction by vacuum. Larger particles of powder which do not fully penetrate the stranded material may be combed into the stranded material and powder which does not impregnate the stranded material may be collected and reused.

Vacuum powder injector and method of impregnating fiber with powder

NASA Technical Reports Server (NTRS)

Working, Dennis C. (Inventor)

1993-01-01

A method and apparatus uniformly impregnate stranded material with dry powder such as low solubility, high melt flow polymer powder to produce, for example, composite prepregs. The stranded material is expanded in an impregnation chamber by an influx of air so that the powder, which may enter through the same inlet as the air, penetrates to the center of the stranded material. The stranded material then is contracted for holding the powder therein. The stranded material and powder may be pulled through the impregnation chamber in the same direction by vacuum. Larger particles of powder which do not fully penetrate the stranded material may be combed into the stranded material and powder which does not impregnate the stranded material may be collected and reused.

Method for synthesizing ultrafine powder materials

DOEpatents

Buss, Richard J.; Ho, Pauline

1988-01-01

A method for synthesizing ultrafine powder materials, for example, ceramic and metal powders, comprises admitting gaseous reactants from which the powder material is to be formed into a vacuum reaction chamber maintained at a pressure less than atmospheric and at a temperature less than about 400.degree. K. (127.degree.C.). The gaseous reactants are directed through a glow discharge provided in the vacuum reaction chamber to form the ultrafine powder material.

Aggregate breakdown of nanoparticulate titania

NASA Astrophysics Data System (ADS)

Venugopal, Navin

Six nanosized titanium dioxide powders synthesized from a sulfate process were investigated. The targeted end-use of this powder was for a de-NOx catalyst honeycomb monolith. Alteration of synthesis parameters had resulted principally in differences in soluble ion level and specific surface area of the powders. The goal of this investigation was to understand the role of synthesis parameters in the aggregation behavior of these powders. Investigation via scanning electron microscopy of the powders revealed three different aggregation iterations at specific length scales. Secondary and higher order aggregate strength was investigated via oscillatory stress rheometry as a means of simulating shear conditions encountered during extrusion. G' and G'' were measured as a function of the applied oscillatory stress. Oscillatory rheometry indicated a strong variation as a function of the sulfate level of the particles in the viscoelastic yield strengths. Powder yield stresses ranged from 3.0 Pa to 24.0 Pa of oscillatory stress. Compaction curves to 750 MPa found strong similarities in extrapolated yield point of stage I and II compaction for each of the powders (at approximately 500 MPa) suggesting that the variation in sulfate was greatest above the primary aggregate level. Scanning electron microscopy of samples at different states of shear in oscillatory rheometry confirmed the variation in the linear elastic region and the viscous flow regime. A technique of this investigation was to approach aggregation via a novel perspective: aggregates are distinguished as being loose open structures that are highly disordered and stochastic in nature. The methodology used was to investigate the shear stresses required to rupture the various aggregation stages encountered and investigate the attempt to realign the now free-flowing constituents comprising the aggregate into a denser configuration. Mercury porosimetry was utilized to measure the pore size of the compact resulting from compaction via dry pressing and tape casting secondary scale aggregates. Mercury porosimetry of tapes cast at 0.85 and 9.09 cm/sec exhibited pore sizes ranging from 200-500 nm suggesting packing of intact micron-sized primary aggregates. Porosimetry further showed that this peak was absent in pressed pellets corroborating arguments of ruptured primary aggregates during compaction to 750 MPa.

Consumer acceptance and aroma characterization of navy bean (Phaseolus vulgaris) powders prepared by extrusion and conventional processing methods.

PubMed

Szczygiel, Edward J; Harte, Janice B; Strasburg, Gale M; Cho, Sungeun

2017-09-01

Food products produced with bean ingredients are gaining in popularity among consumers due to the reported health benefits. Navy bean (Phaseolus vulgaris) powder produced through extrusion can be considered as a resource-efficient alternative to conventional methods, which often involve high water inputs. Therefore, navy bean powders produced with extrusion and conventional methods were assessed for the impact of processing on consumer liking in end-use products and odor-active compounds. Consumer acceptance results reveal significant differences in flavor, texture and overall acceptance scores of several products produced with navy bean powder. Crackers produced with extruded navy bean powder received higher hedonic flavor ratings than those produced with commercial navy bean powder (P < 0.001). GC-O data showed that the commercial powder produced through conventional processing had much greater contents of several aliphatic aldehydes commonly formed via lipid oxidation, such as hexanal, octanal and nonanal with descriptors of 'grassy', 'nutty', 'fruity', 'dusty', and 'cleaner', compared to the extruded powder. Extrusion processed navy bean powders were preferred over commercial powders for certain navy bean powder applications. This is best explained by substantial differences in aroma profiles of the two powders that may have been caused by lipid oxidation. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Carburizing treatment of low alloy steels: Effect of technological parameters

NASA Astrophysics Data System (ADS)

Benarioua, Younes

2018-05-01

The surface areas of the parts subjected to mechanical loads influence to a great extent the resistance to wear and fatigue. In majority of cases, producing of a hard superficial layer on a tough substrate is conducive to an increased resistance to mechanical wear and fatigue. Cementation treatment of low alloy steels which bonds superficial martensitic layer of high hardness and lateral compressive to a core of lower hardness and greater toughness is an example of a good solution of the problem. The high hardness of the martensitic layer is due to an increased concentration of interstitial carbon atoms in the austenite before quenching. The lower hardness of the core after quenching is due to the presence of ferrite and pearlite components which appear if the cooling rate after austenitization becomes lower than the critical on. The objective of the present study was to obtain a cemented surface layer on low alloy steel by means of pack carburizing treatment. Different steel grades, austenitization temperatures as well as different soaking times were used as parameters of the pack carburizing treatment. During this treatment, carbon atoms from the pack powder diffuse toward the steels surface and form compounds of iron carbides. The effect of carburizing parameters on the transformation rate of low carbon surface layer of the low alloy steel to the cemented one was investigated by several analytical techniques.

Packing Polymorphism of Dapivirine and Its Impact on the Performance of a Dapivirine-Releasing Silicone Elastomer Vaginal Ring.

PubMed

McCoy, Clare F; Murphy, Diarmaid J; Boyd, Peter; Derrick, Tiffany; Spence, Patrick; Devlin, Brid; Malcolm, R Karl

2017-08-01

A silicone elastomer vaginal ring providing sustained release over 28 days of the anti-retroviral microbicide dapivirine has recently completed phase III clinical testing and showed moderate protection against HIV acquisition. In support of the product licensure program, we report the impact of dapivirine packing polymorphism on the thermal and solubility characteristics of dapivirine and on the in vitro performance of the 25 mg dapivirine ring product. This is the first time that polymorphism has been reported for a drug-releasing vaginal ring product. Thermal, particle size, powder X-ray diffraction, and thermodynamic solubility analyses of dapivirine polymorphic forms I and IV, both of which are persistent at room temperature and with form I being the thermodynamically stable form, were conducted for both micronized and non-micronized materials. No significant differences in solubility between DPV forms I and IV were observed in media commonly used for in vitro release testing. Matrix-type silicone elastomer vaginal rings were manufactured and the impact of dapivirine polymorphism on key in vitro parameters (compression and tensile behavior; content assay; in vitro release; residual content assay) was investigated. The data demonstrate that dapivirine packing polymorphism has no significant impact on in vitro performance of the 25 mg dapivirine vaginal ring. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Explosion risk evaluation during production of coating powder.

PubMed

Li, Gang; Yuan, Chunmiao; Chen, Baozhi

2007-10-22

Powder coating is widely used in industry to prevent equipment corrosion. More than 600 companies produce coating powder in China, but most do not understand the explosion hazard of such products. In the present investigation the explosibility parameters of a coating powder were determined. Results showed that the coating powder is explosible, though the ignition energy is higher than those of normal dusts such as coal powder and corn starch. Based on these experimental findings, a systematic explosion protection method is proposed, with explosion isolation and explosion venting being adopted as the main protective methods.

Packing microstructure and local density variations of experimental and computational pebble beds

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

Auwerda, G. J.; Kloosterman, J. L.; Lathouwers, D.

2012-07-01

In pebble bed type nuclear reactors the fuel is contained in graphite pebbles, which form a randomly stacked bed with a non-uniform packing density. These variations can influence local coolant flow and power density and are a possible cause of hotspots. To analyse local density variations computational methods are needed that can generate randomly stacked pebble beds with a realistic packing structure on a pebble-to-pebble level. We first compare various properties of the local packing structure of a computed bed with those of an image made using computer aided X-ray tomography, looking at properties in the bulk of the bedmore » and near the wall separately. Especially for the bulk of the bed, properties of the computed bed show good comparison with the scanned bed and with literature, giving confidence our method generates beds with realistic packing microstructure. Results also show the packing structure is different near the wall than in the bulk of the bed, with pebbles near the wall forming ordered layers similar to hexagonal close packing. Next, variations in the local packing density are investigated by comparing probability density functions of the packing fraction of small clusters of pebbles throughout the bed. Especially near the wall large variations in local packing fractions exists, with a higher probability for both clusters of pebbles with low (<0.6) and high (>0.65) packing fraction, which could significantly affect flow rates and, together with higher power densities, could result in hotspots. (authors)« less

Lower conjunctival fornix packing for mydriasis in premature infants: a randomized trial

PubMed Central

Thanathanee, Onsiri; Ratanapakorn, Tanapat; Morley, Michael G; Yospaiboon, Yosanan

2012-01-01

Objective To compare the mydriatic effect of lower conjunctival fornix packing to conventional instillation of eyedrops containing 2.5% phenylephrine and 1% tropicamide in premature infants undergoing examination for retinopathy of prematurity. Methods The patients were randomized to receive either conventional instillation of mydriatic drops or lower conjunctival fornix packing in one eye and the alternate method in the fellow eye. For the eyes receiving lower conjunctival fornix packing (study group), one small piece of the cotton wool soaked with one drop of 2.5% phenylephrine and one drop of 1% tropicamide was packed in the lower conjunctival fornix for 15 minutes. For the eyes receiving the conventional instillation (control group), 2.5% phenylephrine and 1% tropicamide were alternately instilled every 5 minutes for two doses each. Horizontal pupil diameter was measured with a ruler in millimeters 40 minutes later. Results The mean dilated pupil diameter in study group and control group were 5.76 ± 1.01 mm and 4.50 ± 1.08 mm, respectively. This difference was statistically significant (P < 0.05). Conclusion The dilated pupil diameter after receiving the lower conjunctival fornix packing was larger than conventional instillation with a statistically significant difference. We recommended the packing method to dilate the preterm infant pupil, especially if the pupil is difficult to dilate. PMID:22368443

A reliability design method for a lithium-ion battery pack considering the thermal disequilibrium in electric vehicles

NASA Astrophysics Data System (ADS)

Xia, Quan; Wang, Zili; Ren, Yi; Sun, Bo; Yang, Dezhen; Feng, Qiang

2018-05-01

With the rapid development of lithium-ion battery technology in the electric vehicle (EV) industry, the lifetime of the battery cell increases substantially; however, the reliability of the battery pack is still inadequate. Because of the complexity of the battery pack, a reliability design method for a lithium-ion battery pack considering the thermal disequilibrium is proposed in this paper based on cell redundancy. Based on this method, a three-dimensional electric-thermal-flow-coupled model, a stochastic degradation model of cells under field dynamic conditions and a multi-state system reliability model of a battery pack are established. The relationships between the multi-physics coupling model, the degradation model and the system reliability model are first constructed to analyze the reliability of the battery pack and followed by analysis examples with different redundancy strategies. By comparing the reliability of battery packs of different redundant cell numbers and configurations, several conclusions for the redundancy strategy are obtained. More notably, the reliability does not monotonically increase with the number of redundant cells for the thermal disequilibrium effects. In this work, the reliability of a 6 × 5 parallel-series configuration is the optimal system structure. In addition, the effect of the cell arrangement and cooling conditions are investigated.

Application of a dye-binding method for the determination of available lysine in skim milk powders.

PubMed

Aalaei, Kataneh; Rayner, Marilyn; Tareke, Eden; Sjöholm, Ingegerd

2016-04-01

A dye-binding method using Acid Orange 12 was investigated regarding its suitability for the quantification of available lysine, as a means of monitoring the Maillard reaction in skim milk powders. The method was evaluated by analyzing a wide range of milk powders produced by three different drying methods and stored under various conditions. A pilot-scale freeze-dryer, spray-dryer and drum-dryer were used to produce skim milk powders and the samples were stored at two temperatures (20 °C and 30 °C) and two relative humidities (33% and 52%) under strictly controlled conditions. Moreover to validate the method, two protein isolates; bovine serum albumin and casein were investigated for their available lysine content. The results demonstrate the suitability of this method for measuring the available lysine in skim milk powders with good precision and high reproducibility. The relative standard deviations obtained from the 125 freeze-dried powders were 1.8%, and those from the 100 drum-dried samples were all 1.9%. The highest variation was found for the spray-dried powders, which showed relative standard deviations between 0.9% and 6.7%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of Female-Oriented Cigarette Packaging in the United States

PubMed Central

Doxey, Juliana; Daniel, Samantha; Bansal-Travers, Maansi

2011-01-01

Introduction: Cigarette packaging is among the most prominent forms of tobacco marketing. This study examined the impact of cigarette pack design among young women in the United States. Method: A national sample of 18- to 19-year-old females in the United States completed an online survey in February 2010. Participants were randomized to view eight cigarette packs designed according to one of four experimental conditions: fully branded female packs, same packs without descriptors (e.g., “slims”), same packs without brand imagery or descriptors (“plain” packs), and branded non-female brands. Participants rated packs on measures of appeal and health risk and completed a behavioral pack selection task. Results: Fully branded female packs were rated significantly more appealing than the same packs without descriptors, “plain” packs, and non–female-branded packs. Female-branded packs were associated with a greater number of positive attributes including glamour, slimness, and attractiveness and were more likely to be perceived as less harmful. Approximately 40% of smokers and nonsmokers requested a pack at the end of the study; female-branded packs were 3 times more likely to be selected than plain packs. Conclusion: Plain packaging and removing descriptors such as “slims” from cigarette packs may reduce smoking susceptibility among young women. PMID:21486994

Impact of the long chain omega-acylceramides on the stratum corneum lipid nanostructure. Part 1: Thermotropic phase behaviour of CER[EOS] and CER[EOP] studied using X-ray powder diffraction and FT-Raman spectroscopy.

PubMed

Kessner, Doreen; Brezesinski, Gerald; Funari, Sergio S; Dobner, Bodo; Neubert, Reinhard H H

2010-01-01

The stratum corneum (SC), the outermost layer of the mammalian skin, is the main skin barrier. Ceramides (CERs) as the major constituent of the SC lipid matrix are of particular interest. At the moment, 11 classes of CERs are identified, but the effect of each single ceramide species is still not known. Therefore in this article, the thermotropic behaviour of the long chain omega-acylceramides CER[EOS] and CER[EOP] was studied using X-ray powder diffraction and FT-Raman spectroscopy. It was found that the omega-acylceramides CER[EOS] and CER[EOP] do not show a pronounced polymorphism which is observed for shorter chain ceramides as a significant feature. The phase behaviour of both ceramides is strongly influenced by the extremely long acyl-chain residue. The latter has a much stronger influence compared with the structure of the polar head group, which is discussed as extremely important for the appearance of a rich polymorphism. Despite the strong influence of the long chain, the additional OH-group of the phyto-sphingosine type CER[EOP] influences the lamellar repeat distance and the chain packing. The less polar sphingosine type CER[EOS] is stronger influenced by the long acyl-chain residue. Hydration is necessary for the formation of an extended hydrogen-bonding network between the polar head groups leading to the appearance of a long-periodicity phase (LPP). In contrast, the more polar CER[EOP] forms the LPP with densely packed alkyl chains already in the dry state.

Method for making a non-extractable stationary phase of polymer within a capillary column

DOEpatents

Springston, Stephen R.

1990-01-01

A method for coating interior capillary column surfaces, or packing material of a packed column, used for gas chromatography, with a stationary polymer phase that is cross-linked by exposing it to a low-temperature plasma that is uniformly distributed over the column or packing material for a predetermined period of time to effect the desired degree of cross-linking of the coating.

Identification of RIP-II toxins by affinity enrichment, enzymatic digestion and LC-MS.

PubMed

Fredriksson, Sten-Åke; Artursson, Elisabet; Bergström, Tomas; Östin, Anders; Nilsson, Calle; Åstot, Crister

2015-01-20

Type 2 ribosome-inactivating protein toxins (RIP-II toxins) were enriched and purified prior to enzymatic digestion and LC-MS analysis. The enrichment of the RIP-II family of plant proteins, such as ricin, abrin, viscumin, and volkensin was based on their affinity for galactosyl moieties. A macroporous chromatographic material was modified with a galactose-terminated substituent and packed into miniaturized columns that were used in a chromatographic system to achieve up to 1000-fold toxin enrichment. The galactose affinity of the RIP-II proteins enabled their selective enrichment from water, beverages, and extracts of powder and wipe samples. The enriched fractions were digested with trypsin and RIP-II peptides were identified based on accurate mass LC-MS data. Their identities were unambiguously confirmed by LC-MS/MS product ion scans of peptides unique to each of the toxins. The LC-MS detection limit achieved for ricin target peptides was 10 amol and the corresponding detection limit for the full method was 10 fmol/mL (0.6 ng/mL). The affinity enrichment method was applied to samples from a forensic investigation into a case involving the illegal production of ricin and abrin toxins.

[Separation/preconcentration of trace rare earth elements in Tricholoma giganteum by micro-column with nanometer A1203 and their determination by ICP-AES].

PubMed

Liu, Hong-gao; Wang, Yuan-zhong

2010-01-01

Using a micro-column packed with immobilized 1-phenyl-3-methyl-4-bonzoil-5-pyrazone(PMBP) on nanometer Al2O3 powder as the adsorption material, the adsorption and elution behaviors of rare earth ions (Sc3+, Y3+ and La3+) on the above material under dynamic conditions were studied with inductively coupled plasma-atomic emission spectrometry. The conditions for preconcentration of rare earth ions were optimized, and the results show that the studied ions can be adsorbed quantitatively on the above material at pH 4.5 and the analytes adsorbed on the column can be eluted with 0.5 mol x L(-1) HCl solution. The detection limits of the method for Sc, Y and La were 0.15, 0.18 and 0.34 microg x L(-1), respectively, and the relative standard deviations were 2.5%, 3.0% and 1.7%, respectively (n=12, c = 0.5 mg x L(-1)). The proposed method was applied to the determination of trace amount of Sc, Y and La in Tricholoma giganteum with satisfactory results.

Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder.

PubMed

Okada, Kiyoshi; Hasegawa, Fumikazu; Kameshima, Yoshikazu; Nakajima, Akira

2007-05-01

Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only

Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder.

PubMed

Okada, Kiyoshi; Hasegawa, Fumikazu; Kameshima, Yoshikazu; Nakajima, Akira

2007-08-01

Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot-pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only < or =0.4 vol%, it is concluded that this preparation method is very effective in generating bioactivity in polymer-matrix composites by loading with only very small amounts of ceramic powder.

Development of Modern Methods for Determination of Stabilizers in Propellants

DTIC Science & Technology

1996-04-01

powder will! . gtve information Jbout the history of this powder and an indication of its future: usefulness. In othdrs words, the determination of...been excluded in Tables I and II. According to Table I, in order to develop an HPLC method for DPA-stabilized powders , the products that should be... powders were determined by each country using its own HPLC method . The results are given in Table XVI. As indicated, the agreement between the two

Application of l-cystine modified zeolite for preconcentration and determination of ultra-trace levels of cadmium by flame atomic absorption spectrometry.

PubMed

Rezvani, Seyyed Ahmad; Soleymanpour, Ahmad

2016-03-04

A very convenient, sensitive and precise solid phase extraction (SPE) system was developed for enrichment and determination of ultra-trace of cadmium ion in water and plant samples. This method was based on the retention of cadmium(II) ions by l-cystine adsorbed in Y-zeolite and carry out in a packed mini-column. The retained cadmium ions then were eluted and determined by flame atomic absorption spectrometry. The scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and Fourier Transform Infrared (FT-IR) spectroscopy techniques were applied for the characterization of cystine modified zeolite (CMZ). Some experimental conditions affecting the analytical performance such as pH, eluent type, concentration of sample, eluent flow rate and also the presence of interfering ions were investigated. The calibration graph was linear within the range of 0.1-7.5ngmL(-1) and limit of detection was obtained 0.04ngmL(-1) with the preconcentration factor of 400. The relative standard deviation (RSD) was obtained 1.4%, indicating the excellent reproducibility of this method. The proposed method was successfully applied for the extraction and determination of cadmium(II) ion in black tea, cigarette's tobacco and also various water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of blueberry powder produced via foam-mat freeze-drying versus spray-drying: evaluation of foam and powder properties.

PubMed

Darniadi, Sandi; Ho, Peter; Murray, Brent S

2018-03-01

Blueberry juice powder was developed via foam-mat freeze-drying (FMFD) and spray-drying (SD) via addition of maltodextrin (MD) and whey protein isolate (WPI) at weight ratios of MD/WPI = 0.4 to 3.2 (with a fixed solids content of 5 wt% for FMFD and 10 wt% for SD). Feed rates of 180 and 360 mL h -1 were tested in SD. The objective was to evaluate the effect of the drying methods and carrier agents on the physical properties of the corresponding blueberry powders and reconstituted products. Ratios of MD/WPI = 0.4, 1.0 and 1.6 produced highly stable foams most suitable for FMFD. FMFD gave high yields and low bulk density powders with flake-like particles of large size that were also dark purple with high red values. SD gave low powder recoveries. The powders had higher bulk density and faster rehydration times, consisting of smooth, spherical and smaller particles than in FMFD powders. The SD powders were bright purple but less red than FMFD powders. Solubility was greater than 95% for both FMFD and SD powders. The FMFD method is a feasible method of producing blueberry juice powder and gives products retaining more characteristics of the original juice than SD. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Method for converting sucrose to .beta.-D-glucose

DOEpatents

Simmons, Blake A [San Francisco, CA; Volponi, Joanne V [Livermore, CA; Ingersoll, David [Albuquerque, NM; Walker, Andrew [Woodinville, WA

2009-07-07

Disclosed is an apparatus and method for continuously converting sucrose to .beta.-D-glucose. The method comprises a three-stage enzymatic reactor in which an aqueous solution of sucrose is first converted into a solution of fructose and .alpha.-D-glucose by passing it through a porous, packed column containing an inert media on which invertase is immobilized. This solution is then sent through a second packed column containing glucose isomerase and finally a third packed column containing mutarotase. Solution temperature and pH are adjusted to maximize glucose output.

Article and method of forming an article

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

Lacy, Benjamin Paul; Kottilingam, Srikanth Chandrudu; Dutta, Sandip

Provided are an article and a method of forming an article. The method includes providing a metallic powder, heating the metallic powder to a temperature sufficient to joint at least a portion of the metallic powder to form an initial layer, sequentially forming additional layers in a build direction by providing a distributed layer of the metallic powder over the initial layer and heating the distributed layer of the metallic powder, repeating the steps of sequentially forming the additional layers in the build direction to form a portion of the article having a hollow space formed in the build direction,more » and forming an overhang feature extending into the hollow space. The article includes an article formed by the method described herein.« less

Densest local sphere-packing diversity. II. Application to three dimensions

NASA Astrophysics Data System (ADS)

Hopkins, Adam B.; Stillinger, Frank H.; Torquato, Salvatore

2011-01-01

The densest local packings of N three-dimensional identical nonoverlapping spheres within a radius Rmin(N) of a fixed central sphere of the same size are obtained for selected values of N up to N=1054. In the predecessor to this paper [A. B. Hopkins, F. H. Stillinger, and S. Torquato, Phys. Rev. EPLEEE81063-651X10.1103/PhysRevE.81.041305 81, 041305 (2010)], we described our method for finding the putative densest packings of N spheres in d-dimensional Euclidean space Rd and presented those packings in R2 for values of N up to N=348. Here we analyze the properties and characteristics of the densest local packings in R3 and employ knowledge of the Rmin(N), using methods applicable in any d, to construct both a realizability condition for pair correlation functions of sphere packings and an upper bound on the maximal density of infinite sphere packings. In R3, we find wide variability in the densest local packings, including a multitude of packing symmetries such as perfect tetrahedral and imperfect icosahedral symmetry. We compare the densest local packings of N spheres near a central sphere to minimal-energy configurations of N+1 points interacting with short-range repulsive and long-range attractive pair potentials, e.g., 12-6 Lennard-Jones, and find that they are in general completely different, a result that has possible implications for nucleation theory. We also compare the densest local packings to finite subsets of stacking variants of the densest infinite packings in R3 (the Barlow packings) and find that the densest local packings are almost always most similar as measured by a similarity metric, to the subsets of Barlow packings with the smallest number of coordination shells measured about a single central sphere, e.g., a subset of the fcc Barlow packing. Additionally, we observe that the densest local packings are dominated by the dense arrangement of spheres with centers at distance Rmin(N). In particular, we find two “maracas” packings at N=77 and N=93, each consisting of a few unjammed spheres free to rattle within a “husk” composed of the maximal number of spheres that can be packed with centers at respective Rmin(N).

Clinical analysis of speculum-based vaginal packing for high-dose-rate intracavitary tandem and ovoid brachytherapy in cervical cancer

PubMed Central

Sud, Shivani; Roth, Toni

2018-01-01

Purpose Intra-vaginal packing is used to fix the applicator and displace organs at risk (OAR) during high-dose-rate intracavitary tandem and ovoid brachytherapy (HDR-ICB). We retain the speculum from applicator placement as a dual-function bladder and rectum retractor during treatment. Our objective is to review salient techniques for OAR displacement, share our packing technique, and determine the reduction in dose to OAR and inter-fraction variability of dose to OAR, associated with speculum-based vaginal packing (SBVP) in comparison to conventional gauze packing during HDR-ICB. Material and methods We reviewed HDR-ICB treatment plans for 45 patients, including 10 who underwent both conventional gauze packing and SBVP. Due to institutional inter-provider practice differences, patients non-selectively received either packing procedure. Packing was performed under conscious sedation, followed by cone beam computed tomography used for dosimetric planning. Maximum absolute and percent-of-prescription dose to the International Commission of Radiation Units bladder and rectal points in addition to D0.1cc, D1.0cc, and D2.0cc volumes of the bladder and rectum were analyzed and compared for each packing method using an independent sample t-test. Results Of the 179 fractions included, 73% and 27% used SBVP and gauze packing, respectively. For patients prescribed 6 Gy to point A, SBVP was associated with reduced mean D0.1cc bladder dose, inter-fraction variability in D0.1cc bladder dose by 9.3% (p = 0.026) and 9.0%, respectively, and statistically equivalent rectal D0.1cc, D1.0cc, and D2.0cc. Patients prescribed 5.5 Gy or 5 Gy to point A after dose optimization, were less likely to benefit from SBVP. In the intra-patient comparison, 80% of patients had reduction in at least one rectum or bladder parameter. Conclusions In patients with conducive anatomy, SBVP is a cost-efficient packing method that is associated with improved bladder sparing and comparable rectal sparing relative to gauze packing during HDR-ICB without general anesthesia. PMID:29619054

Extrusion and rheology of fine particulate ceramic pastes

NASA Astrophysics Data System (ADS)

Mazzeo, Fred Anthony

A rheological study was conducted on an extruded blend of two alumina powders, Alcoa A-3500-SG and Reynolds ERC. These extruded blends were mixed in four compositions, varying in distribution modulus. This work focuses on the interaction of the composition components, mainly particle size distribution and amount of water at a constant binder amount. The rheological parameters of extruded pastes, Sigma, Tau, alpha and beta, were determined by using capillary rheometry modeling by the methodology set forth by Benbow and Bridgwater. This methodology makes use of capillary rheometer to determine extrusion parameters, which describe the flow behavior of a paste. The parameter values are indirectly determined by extrapolating high shear rate information obtained by the extrusion process. A goal of this research was to determine fundamental rheological properties directly from fundamental rheological equations of state. This was accomplished by assessing the material properties by using a dynamic stress rheometer. The rheological parameters used in this study to characterize the paste are elastic modulus, viscosity, tan delta, and relaxation time. This technique approaches a step closer in understanding the microstructural influence on flow behavior of a paste. This method directly determines rheological properties by using linear viscoelastic theory, giving a quantitative analysis of material properties. A strong correlation between the elastic modulus and sigma, and viscosity and alpha is shown to exist, indicating a relationship between these two techniques. Predictive process control methodology, based on particle packing modeling, quantitatively determined structural parameters useful in evaluating a composition. The determined parameters are: distribution modulus, interparticle separation distance, porosity, and particle crowding index, which are important to understand the extrudates packed state. A connection between the physical structure of the extrudate and its rheological behavior, can lead to a better understanding of what conditions and parameters are necessary to characterize the extrusion process. This study shows how particle packing and particle size influences the rheological behavior of the paste. Results showed that an optimally packed system was found to occur at a distribution modulus of 0.51. This system was determined both experimentally and quantitatively to exhibit the lowest porosity at any water content. The 0.51 system required a lower amount of water to extrude and the parameters of both rheological techniques agreed well, in which all parameters are influenced by the packing state of the paste, and a consistent trend was generally found. The capillary rheometry results can be explained by the strong interaction of particles that occurs at high shear rates. The dynamic stress rheometer results can be explained by the particle packing characteristics, interparticle separation distance and particle-crowding index, and the capillary forces between particles. The excess amount of liquid that is present in the structure decreases the role of the capillary attraction between particles and an increase in the particle size role on the rheological behavior of the pastes occurs.

Radiative-Transfer Modeling of Spectra of Densely Packed Particulate Media

NASA Astrophysics Data System (ADS)

Ito, G.; Mishchenko, M. I.; Glotch, T. D.

2017-12-01

Remote sensing measurements over a wide range of wavelengths from both ground- and space-based platforms have provided a wealth of data regarding the surfaces and atmospheres of various solar system bodies. With proper interpretations, important properties, such as composition and particle size, can be inferred. However, proper interpretation of such datasets can often be difficult, especially for densely packed particulate media with particle sizes on the order of wavelength of light being used for remote sensing. Radiative transfer theory has often been applied to the study of densely packed particulate media like planetary regoliths and snow, but with difficulty, and here we continue to investigate radiative transfer modeling of spectra of densely packed media. We use the superposition T-matrix method to compute scattering properties of clusters of particles and capture the near-field effects important for dense packing. Then, the scattering parameters from the T-matrix computations are modified with the static structure factor correction, accounting for the dense packing of the clusters themselves. Using these corrected scattering parameters, reflectance (or emissivity via Kirchhoff's Law) is computed with the method of invariance imbedding solution to the radiative transfer equation. For this work we modeled the emissivity spectrum of the 3.3 µm particle size fraction of enstatite, representing some common mineralogical and particle size components of regoliths, in the mid-infrared wavelengths (5 - 50 µm). The modeled spectrum from the T-matrix method with static structure factor correction using moderate packing densities (filling factors of 0.1 - 0.2) produced better fits to the laboratory measurement of corresponding spectrum than the spectrum modeled by the equivalent method without static structure factor correction. Future work will test the method of the superposition T-matrix and static structure factor correction combination for larger particles sizes and polydispersed clusters in search for the most effective modeling of spectra of densely packed particulate media.

Method for making a non-extractable stationary phase of polymer within a capillary column

DOEpatents

Springston, S.R.

1990-10-30

A method is described for coating interior capillary column surfaces, or packing material of a packed column, used for gas chromatography, with a stationary polymer phase that is cross-linked by exposing it to a low-temperature plasma that is uniformly distributed over the column or packing material for a predetermined period of time to effect the desired degree of cross-linking of the coating. 7 figs.

Effect of high-dose irradiation on quality characteristics of ready-to-eat broiler breast fillets stored at room temperature.

PubMed

Baptista, R F; Teixeira, C E; Lemos, M; Monteiro, M L G; Vital, H C; Mársico, E T; Júnior, C A Conte; Mano, S B

2014-10-01

The effect of high-dose irradiation on the physical, chemical, and bacteriological parameters of ready-to-eat vacuum-packed broiler breast meat after 430 d of storage at room temperature was investigated. Ready-to-eat broiler breast fillets were immersed in brine with garlic powder and then drained, grilled, and vacuum-packed (primary packaging). The high-dose irradiation used was approximately 48 kGy. The treatments were designated as A (irradiated samples stored at room temperature), B (irradiated samples stored at -25°C), and C (nonirradiated samples stored at -25°C). All samples were packaged in polyethylene bags containing aluminum to exclude light (secondary packaging). Proximate composition, pH, 2-thiobarbituric acid reactive substance (TBARS), and heterotrophic aerobic mesophilic bacteria were analyzed during 430 d of storage. Results were analyzed using 1-way ANOVA and the Tukey test. Linear regression was used to analyze the correlation between the results for each parameter and storage time of the different treatments. The gamma radiation caused slight changes (P < 0.05) in the moisture and fat content, regardless of storage temperature. After storage d 110, TBARS values remained stable (P > 0.05) in all the treatments. The preservation methods used were effective in maintaining the mesophilic counts below the detection level during the entire storage period. We concluded that, among the treatments studied, high-dose irradiation with storage at room temperature showed potential for the preservation of ready-to-eat products made from poultry meat, to provide foods safe for consumption. ©2014 Poultry Science Association Inc.

Magnetic topology of Co-based inverse opal-like structures

NASA Astrophysics Data System (ADS)

Grigoryeva, N. A.; Mistonov, A. A.; Napolskii, K. S.; Sapoletova, N. A.; Eliseev, A. A.; Bouwman, W.; Byelov, D. V.; Petukhov, A. V.; Chernyshov, D. Yu.; Eckerlebe, H.; Vasilieva, A. V.; Grigoriev, S. V.

2011-08-01

The magnetic and structural properties of a cobalt inverse opal-like crystal have been studied by a combination of complementary techniques ranging from polarized neutron scattering and superconducting quantum interference device (SQUID) magnetometry to x-ray diffraction. Microradian small-angle x-ray diffraction shows that the inverse opal-like structure (OLS) synthesized by the electrochemical method fully duplicates the three-dimensional net of voids of the template artificial opal. The inverse OLS has a face-centered cubic (fcc) structure with a lattice constant of 640±10 nm and with a clear tendency to a random hexagonal close-packed structure along the [111] axes. Wide-angle x-ray powder diffraction shows that the atomic cobalt structure is described by coexistence of 95% hexagonal close-packed and 5% fcc phases. The SQUID measurements demonstrate that the inverse OLS film possesses easy-plane magnetization geometry with a coercive field of 14.0 ± 0.5 mT at room temperature. The detailed picture of the transformation of the magnetic structure under an in-plane applied field was detected with the help of small-angle diffraction of polarized neutrons. In the demagnetized state the magnetic system consists of randomly oriented magnetic domains. A complex magnetic structure appears upon application of the magnetic field, with nonhomogeneous distribution of magnetization density within the unit element of the OLS. This distribution is determined by the combined effect of the easy-plane geometry of the film and the crystallographic geometry of the opal-like structure with respect to the applied field direction.

A real-time insulation detection method for battery packs used in electric vehicles

NASA Astrophysics Data System (ADS)

Tian, Jiaqiang; Wang, Yujie; Yang, Duo; Zhang, Xu; Chen, Zonghai

2018-05-01

Due to the energy crisis and environmental pollution, electric vehicles have become more and more popular. Compared to traditional fuel vehicles, the electric vehicles are integrated with more high-voltage components, which have potential security risks of insulation. The insulation resistance between the chassis and the direct current bus of the battery pack is easily affected by factors such as temperature, humidity and vibration. In order to ensure the safe and reliable operation of the electric vehicles, it is necessary to detect the insulation resistance of the battery pack. This paper proposes an insulation detection scheme based on low-frequency signal injection method. Considering the insulation detector which can be easily affected by noises, the algorithm based on Kalman filter is proposed. Moreover, the battery pack is always in the states of charging and discharging during driving, which will lead to frequent changes in the voltage of the battery pack and affect the estimation accuracy of insulation detector. Therefore the recursive least squares algorithm is adopted to solve the problem that the detection results of insulation detector mutate with the voltage of the battery pack. The performance of the proposed method is verified by dynamic and static experiments.

Marginal rigidity and history dependence in packings of attractive athermal emulsions

NASA Astrophysics Data System (ADS)

Bargteil, Dylan; Pontani, Lea-Laetitia; Brujic, Jasna

2014-03-01

The geometry and stress through particulate packings depends on the method of preparation and the interaction potential between the particles. Previously, we discovered that creaming frictionless, athermal emulsions with a short-range depletion attraction leads to an initial increase in the packing density above random close packing, followed by a monotonic decrease in density (Jorjadze et al, PNAS, 2011). This decrease is because the attractive force stabilizes loose voids, thus reducing the average coordination number, , of the packing. In order to understand the mechanism of packing creation, we investigate whether the final density is influenced by the polydispersity or the initial volume fraction of droplets, as it is in frictional packings. Finally, we compress the attractive packings by centrifugation to probe the scaling laws of pressure versus density and and compare them with those found in repulsive packings (Jorjadze et al, PRL, 2013).

Cryosurgery Planning Using Bubble Packing in 3D

PubMed Central

Tanaka, Daigo; Shimada, Kenji; Rossi, Michael R.; Rabin, Yoed

2008-01-01

As part of an ongoing project to develop automated tools for cryosurgery planning, the current study focuses on the development of a 3D bubble packing method. A proof-of-concept for the new method is demonstrated on five prostate models, reconstructed from ultrasound images. The new method is a modification of an established method in 2D. Ellipsoidal bubbles are packed in the volume of the prostate in the current study; such bubbles can be viewed as a first-order approximation of a frozen region around a single cryoprobe. When all cryoprobes are inserted to the same depth, optimum planning was found to occur at about 60% of the length of the prostate (measured from its apex), which leads to cooling of approximately 75% of the prostate volume below a specific temperature threshold of −22°C. Bubble packing has the potential to dramatically reduce the run time for automated planning. PMID:17963095

Cryosurgery planning using bubble packing in 3D.

PubMed

Tanaka, Daigo; Shimada, Kenji; Rossi, Michael R; Rabin, Yoed

2008-04-01

As part of an ongoing project to develop automated tools for cryosurgery planning, the current study focuses on the development of a 3D bubble packing method. A proof-of-concept for the new method is demonstrated on five prostate models, reconstructed from ultrasound images. The new method is a modification of an established method in 2D. Ellipsoidal bubbles are packed in the volume of the prostate in the current study; such bubbles can be viewed as a first-order approximation of a frozen region around a single cryoprobe. When all cryoprobes are inserted to the same depth, optimum planning was found to occur at about 60% of the length of the prostate (measured from its apex), which leads to cooling of approximately 75% of the prostate volume below a specific temperature threshold of - 22 degrees C. Bubble packing has the potential to dramatically reduce the run time for automated planning.

The Remote Food Photography Method Accurately Estimates Dry Powdered Foods-The Source of Calories for Many Infants.

PubMed

Duhé, Abby F; Gilmore, L Anne; Burton, Jeffrey H; Martin, Corby K; Redman, Leanne M

2016-07-01

Infant formula is a major source of nutrition for infants, with more than half of all infants in the United States consuming infant formula exclusively or in combination with breast milk. The energy in infant powdered formula is derived from the powder and not the water, making it necessary to develop methods that can accurately estimate the amount of powder used before reconstitution. Our aim was to assess the use of the Remote Food Photography Method to accurately estimate the weight of infant powdered formula before reconstitution among the standard serving sizes. For each serving size (1 scoop, 2 scoops, 3 scoops, and 4 scoops), a set of seven test bottles and photographs were prepared as follow: recommended gram weight of powdered formula of the respective serving size by the manufacturer; three bottles and photographs containing 15%, 10%, and 5% less powdered formula than recommended; and three bottles and photographs containing 5%, 10%, and 15% more powdered formula than recommended (n=28). Ratio estimates of the test photographs as compared to standard photographs were obtained using standard Remote Food Photography Method analysis procedures. The ratio estimates and the US Department of Agriculture data tables were used to generate food and nutrient information to provide the Remote Food Photography Method estimates. Equivalence testing using the two one-sided t tests approach was used to determine equivalence between the actual gram weights and the Remote Food Photography Method estimated weights for all samples, within each serving size, and within underprepared and overprepared bottles. For all bottles, the gram weights estimated by the Remote Food Photography Method were within 5% equivalence bounds with a slight underestimation of 0.05 g (90% CI -0.49 to 0.40; P<0.001) and mean percent error ranging between 0.32% and 1.58% among the four serving sizes. The maximum observed mean error was an overestimation of 1.58% of powdered formula by the Remote Food Photography Method under controlled laboratory conditions, indicating that the Remote Food Photography Method accurately estimated infant powdered formula. Copyright © 2016 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

Gravimetric measurement of momentary drying rate of spray freeze-dried powders in vials.

PubMed

Gieseler, Henning; Lee, Geoffrey

2009-09-01

The profile of drying rate versus primary drying time for a spray freeze-dried trehalose aqueous solution is much different from that determined for regular freeze-drying. Drying rate declines very rapidly, attributed to rate-limiting heat transfer through the packed bed of frozen microparticles contained in a vial. The inter-particulate spaces appear to be the cause of this rate limitation. Use of either liquid nitrogen or liquid propane as a cryogenic produced strong differences in both SFD particle morphology and drying rate using trehalose, sucrose, or mannitol. The lack of any evident correlation supports the argument that the inter-particulate voids determine drying behavior.

Mechanochemical synthesis and structural characterization of three novel cocrystals of dimethylglyoxime with N-heterocyclic aromatic compounds and acetamide

NASA Astrophysics Data System (ADS)

Abidi, Syed Sibte Asghar; Azim, Yasser; Gupta, Abhishek Kumar; Pradeep, Chullikkattil P.

2017-12-01

With an aim to explore the interactions of (RR'Cdbnd Nsbnd OH) oxime moiety of dimethylglyoxime (DMG) with pyridyl ring of N-heterocyclic aromatic compounds and acetamide, three novel cocrystals of dimethylglyoxime with acridine (ACR), 1,10-phenanthroline monohydrate (PT) and acetamide (ACT) are reported. These three cocrystals were obtained with a mechanochemical synthesis approach and were characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), fourier transform-infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Additionally, Hirshfeld surface analysis is used to investigate the intermolecular interaction and the crystal packing of cocrystals.

Vacuum Powder Injector

NASA Technical Reports Server (NTRS)

Working, Dennis C.

1991-01-01

Method developed to provide uniform impregnation of bundles of carbon-fiber tow with low-solubility, high-melt-flow polymer powder materials to produce composite prepregs. Vacuum powder injector expands bundle of fiber tow, applies polymer to it, then compresses bundle to hold powder. System provides for control of amount of polymer on bundle. Crystallinity of polymer maintained by controlled melt on takeup system. All powder entrapped, and most collected for reuse. Process provides inexpensive and efficient method for making composite materials. Allows for coating of any bundle of fine fibers with powders. Shows high potential for making prepregs of improved materials and for preparation of high-temperature, high-modulus, reinforced thermoplastics.

Sol-gel synthesis and densification of aluminoborosilicate powders. Part 1: Synthesis

NASA Technical Reports Server (NTRS)

Bull, Jeffrey; Selvaduray, Guna; Leiser, Daniel

1992-01-01

Aluminoborosilicate powders high in alumina content were synthesized by the sol-gel process utilizing various methods of preparation. Properties and microstructural effects related to these syntheses were examined. After heating to 600 C for 2 h in flowing air, the powders were amorphous with the metal oxides comprising 87 percent of the weight and uncombusted organics the remainder. DTA of dried powders revealed a T(sub g) at approximately 835 C and an exotherm near 900 C due to crystallization. Powders derived from aluminum secbutoxide consisted of particles with a mean diameter 5 microns less than those from aluminum isopropoxide. Powders synthesized with aluminum isopropoxide produced agglomerates comprised of rod shaped particulates while powders made with the secbutoxide precursor produced irregular glassy shards. Compacts formed from these powders required different loadings for equivalent densities according to the method of synthesis.

Powder bed binder jet 3D printing of Inconel 718: Densification, microstructural evolution and challenges

DOE PAGES

Nandwana, Peeyush; Elliott, Amy M.; Siddel, Derek; ...

2017-01-03

Traditional manufacturing of Inconel 718 components from castings and thermomechanical processing routes involve extensive post processing and machining to attain the desired geometry. Additive manufacturing (AM) technologies including direct energy deposition (DED), selective laser melting (SLM), electron beam melting (EBM) and binder jet 3D printing (BJ3DP) can minimize scrap generation and reduce lead times. While there is extensive literature on the use of melting and solidification based AM technologies, there has been limited research on the use of binder jet 3D printing. In this paper, a brief review on binder jet additive manufacturing of Inconel 718 is presented. In addition,more » existing knowledge on sintering of Inconel 718 has been extended to binder jet 3D printing. We found that supersolidus liquid phase sintering (SLPS) is necessary to achieve full densification of Inconel 718. SLPS is sensitive to the feedstock chemistry that has a strong influence on the liquid volume fraction at the processing temperature. Based on these results, we discuss an empirical framework to determine the role of powder particle size and liquid volume fraction on sintering kinetics. In conclusion, the role of powder packing factor and binder saturation on microstructural evolution is discussed. The current challenges in the use of BJ3DP for fabrication of Inconel 718, as well as, extension to other metal systems, are presented.« less

Acemetacin cocrystal structures by powder X-ray diffraction.

PubMed

Bolla, Geetha; Chernyshev, Vladimir; Nangia, Ashwini

2017-05-01

Cocrystals of acemetacin drug (ACM) with nicotinamide (NAM), p -aminobenzoic acid (PABA), valerolactam (VLM) and 2-pyridone (2HP) were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD) provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM-NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid-amide dimer three-point synthon R 3 2 (9) R 2 2 (8) R 3 2 (9) with three different syn amides (VLM, 2HP and caprolactam). The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I) or syn (type II). ACM hydrate, ACM-NAM, ACM-NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP) surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O⋯H, N⋯H, Cl⋯H and C⋯H interactions. The physicochemical properties of these cocrystals are under study.

Acemetacin cocrystal structures by powder X-ray diffraction

PubMed Central

Bolla, Geetha

2017-01-01

Cocrystals of acemetacin drug (ACM) with nicotinamide (NAM), p-aminobenzoic acid (PABA), valerolactam (VLM) and 2-pyridone (2HP) were prepared by melt crystallization and their X-ray crystal structures determined by high-resolution powder X-ray diffraction. The powerful technique of structure determination from powder data (SDPD) provided details of molecular packing and hydrogen bonding in pharmaceutical cocrystals of acemetacin. ACM–NAM occurs in anhydrate and hydrate forms, whereas the other structures crystallized in a single crystalline form. The carboxylic acid group of ACM forms theacid–amide dimer three-point synthon R 3 2(9)R 2 2(8)R 3 2(9) with three different syn amides (VLM, 2HP and caprolactam). The conformations of the ACM molecule observed in the crystal structures differ mainly in the mutual orientation of chlorobenzene fragment and the neighboring methyl group, being anti (type I) or syn (type II). ACM hydrate, ACM—NAM, ACM–NAM-hydrate and the piperazine salt of ACM exhibit the type I conformation, whereas ACM polymorphs and other cocrystals adopt the ACM type II conformation. Hydrogen-bond interactions in all the crystal structures were quantified by calculating their molecular electrostatic potential (MEP) surfaces. Hirshfeld surface analysis of the cocrystal surfaces shows that about 50% of the contribution is due to a combination of strong and weak O⋯H, N⋯H, Cl⋯H and C⋯H interactions. The physicochemical properties of these cocrystals are under study. PMID:28512568

Development of an extra-high strength powder metallurgy nickel-base superalloy

NASA Technical Reports Server (NTRS)

Kent, W. B.

1977-01-01

A program was conducted to optimize the composition of NASA IIb-11, an alloy originally developed as a wrought material, for thermal stability and to determine the feasibility for producing the alloy using powder metallurgy techniques. Seven compositions were melted and atomized, hot isostatically pressed, cross rolled to disks and heat treated. Tensile and stress rupture properties from room temperature to 870 C (1600 F) were determined in addition to thermal stability characteristics. Processing variables included hot isostatic pressing parameters and handling, cross rolling procedures and heat treatment cycles. NASA IIb-11E displayed the best combination of overall properties for service as a 760 C (1400 F) disk material. Its composition is 0.06 C, 8.5 Cr, 9.0 Co, 2.0 Mo, 7.1 W, 6.6 Ta, 4.5 Al, 0.75 Ti, 0.5 V, 0.7 Hf, 0.01 B, 0.05 Zr and balance Ni. While the alloy exhibits the highest 760 C (1400 F) rupture strength reported for any powder metallurgy disk alloy to date, additional studies to further evaluate the effects of heat treatment may be required. The alloy is not susceptible to topologically close-packed phase formation during thermal exposure at 870 C (1600 F) for 1,500 hours, but its mechanical property levels are lowered due to grain boundary carbide formation.

Short-term storage of canine preantral ovarian follicles using a powdered coconut water (ACP)-based medium.

PubMed

Lima, G L; Costa, L L M; Cavalcanti, D M L P; Rodrigues, C M F; Freire, F A M; Fontenele-Neto, J D; Silva, A R

2010-07-01

The objective was to investigate the use of powdered coconut water (ACP)-based medium for short-term preservation of canine preantral follicles. Pairs of ovaries from mongrel bitches (n=9) were divided into fragments. One ovarian fragment, treated as a fresh control, was immediately fixed for histological analysis, whereas the other six ovarian fragments were stored either in phosphate-buffered saline (PBS; control group) or ACP medium in isothermal Styrofoam boxes containing biological ice packs. The boxes were sealed and opened only after 12, 24, or 36h. After opening each box, the ovarian fragments were submitted to histological analysis. In total, 12,302 preantral follicles were evaluated, with 64.5% primordial, 33.3% primary, and 2.3% secondary follicles. There were multiple oocytes in 1.3% of the follicles analyzed. At 24h, ACP was more efficient in preserving follicular morphology than PBS (P<0.05). Compared with the fresh control group, a significant reduction in the percentage of morphologically normal ovarian follicles was observed for PBS, starting at 24h; however, the decline started only at 36h for the ACP medium. During the experiment, the temperature inside the isothermal boxes increased from 3 to 9 degrees C (P<0.05), despite a constant room temperature. In conclusion, powdered coconut water (ACP) was an appropriate medium for short-term storage of canine preantral ovarian follicles.

Mid-infrared reflectlance spectra (2.3-22 micions) of sulfur, gold, KBr, MgO, and halon

NASA Technical Reports Server (NTRS)

Nash, D. B.

1986-01-01

Biconical diffuse reflectance spectra in the mid-infrared are presented for powder and other solid forms of sulfur, gold, potassium bromide, magnesium oxide, and halon. Comparisons are made with previously published results of other investigators, and recommendations are made regarding the relative usefulnees of these materials as reflectance standards in the mid-IR. Sulfur has strong intrinsic bands at wavelengths greater than 7 microns that must be taken into account for its use as a reflectance standard. Some sulfur samples have hydrocarbon contaminants and in powder form may have adsorbed water, both of which produce bands in the 3-4-micron region. Potassium bromide has several weak intrinsic bands and is very sensitive to adsorbed water contamination; otherwise it is a good IR reference material. Magnesium oxide and halon have major bands structure and low reflectivity at wavelengths greater than 2.6 microns and thus are unsuitable as reference materials in the mid-IR. Vapor-deposited gold on fine sandpaper (600 grit) is very bright, spectrally flat, and fairly diffuse, so it is the superior material (of those examined) for reflectance reference material throughout the IR. Fine gold powder, on the other hand, is much less bright than evaporated gold, and its reflectivity at wavelengths greater than its particle size is highly sensitive to particle packing density.

Projectile containing metastable intermolecular composites and spot fire method of use

DOEpatents

Asay, Blaine W.; Son, Steven F.; Sanders, V. Eric; Foley, Timothy; Novak, Alan M.; Busse, James R.

2012-07-31

A method for altering the course of a conflagration involving firing a projectile comprising a powder mixture of oxidant powder and nanosized reductant powder at velocity sufficient for a violent reaction between the oxidant powder and the nanosized reductant powder upon impact of the projectile, and causing impact of the projectile at a location chosen to draw a main fire to a spot fire at such location and thereby change the course of the conflagration, whereby the air near the chosen location is heated to a temperature sufficient to cause a spot fire at such location. The invention also includes a projectile useful for such method and said mixture preferably comprises a metastable intermolecular composite.

[Effectiveness of different maintenance methods for codonopsis radix].

PubMed

Shi, Yan-Bin; Wang, Yu-Ping; Li, Yan; Liu, Cheng-Song; Li, Hui-Li; Zhang, Xiao-Yun; Li, Shou-Tang

2014-05-01

To observe different maintenance methods including vacuum-packing, storage together with tobacco, storage together with fennel, ethanol steam and sulfur fumigation for the protection of Codonopsis Radix against mildew and insect damage, and to analyze the content of polysaccharide and flavonoids of Codonopsis Radix tested in this studies, so as to look for the scientific maintenance methods replacing traditional sulfur fumigation. Except for the sulfur fumigation, naturally air-dried Codonopsis Radix was used to investigate the maintenance effectiveness of the above methods, respectively. Mildew was observed by visual inspection, and the content of polysaccharide and flavonoids were determined by ultra-violet and visible spectrophotometer. Comprehensive evaluation was given based on the results of the different maintenance methods. Low-temperature vacuum-packing, ambient-temperature vacuum-packing and sulfur fumigation could keep Codonopsis Radix from mildew and insect damage for one year, but ambient-temperature vacuum-packing showed flatulent phenomenon; ethanol steam could keep Codonopsis Radix from mildew and insects for over half a year; storage together with tobacco or fennel did not have maintenance effect. The difference of polysaccharide and flavonoids contents of all tested Codonopsis Radix was not statistically significant. Low temperature vacuum-packing maintenance can replace traditional sulfur fumigation, and it can maintain the quality of Codonopsis Radix to a certain extent.

Titanium compacts produced by the pulvimetallurgical hydride-dehydride method for biomedical applications.

PubMed

Barreiro, M M; Grana, D R; Kokubu, G A; Luppo, M I; Mintzer, S; Vigna, G

2010-04-01

Titanium powder production by the hydride-dehydride method has been developed as a non-expensive process. In this work, commercially pure grade two Ti specimens were hydrogenated. The hydrided material was milled in a planetary mill. The hydrided titanium powder was dehydrided and then sieved to obtain a particle size between 37 and 125 microm in order to compare it with a commercial powder produced by chemical reduction with a particle size lower than 150 microm. Cylindrical green compacts were obtained by uniaxial pressing of the powders at 343 MPa and sintering in vacuum. The powders and the density of sintered compacts were characterized, the oxygen content was measured and in vivo tests were performed in the tibia bones of Wistar rats in order to evaluate their biocompatibility. No differences were observed between the materials which were produced either with powders obtained by the hydride-dehydride method or with commercial powders produced by chemical reduction regarding modifications in compactation, sintering and biological behaviour.

Impregnation of glass fibres with polymethylmethacrylate using a powder-coating method

NASA Astrophysics Data System (ADS)

Vallittu, Pekka K.

1995-01-01

The aim of this study was to evaluate the usefulness of a powder-coating method to impregnate glass fibres with polymethylmethacrylate (PMMA) for dental purposes. The continuous unidirectional E-glass fibres, the surface of which had been treated with precured silane, were powder-coated with spherical PMMA particles. Before the powder-coated prepregs were used, the incorporated PMMA powder was dissolved with methylmethacrylate monomer. The degree of impregnation of the polymerized composite was determined with a scanning electron microscope. The results revealed that the mean degree of impregnation varied from 0.87 to 0.92, being lower in the heat-cured PMMA group (which simulated fabrication of a new denture), and higher in the autopolymerizing group (which simulated the repair of a fractured denture). The means between the two groups did not, however, differ significantly ( p=0.249). The results suggest that, even though the method has some shortcomings in terms of dental laboratory technology, the powder-coating method can be used to fabricate or repair acrylic resin-based dentures.

Preparation of Cu and Fly Ash Composite by Powder Metallurgy Technique

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

Chew, P. Y.; Lim, P. S.; Ng, M. C.

2011-03-30

Cu and Fly Ash (FA) mixtures with different weight percentages were prepared. Pellets of the mixture powder were produced with the dimension of 17.7 mm in diameter and 10-15 mm in height. These different composites were compacted at a constant pressure of 280 MPa. One of the selected weight percentages was then compacted to form into pellet and sintered at different temperatures which were at 900, 950 and 1000 deg. C respectively for 2 hours. Density of green pellet was measured before sintered in furnace. After sintering, all the pellets with different temperatures were re-weighed and sintered density were calculated.more » The densification of the green and sintered pellets was required to be measured as one of the parameter in selection of the best material properties. Porosity of the pellet shall not be ignored in order to analyze the close-packed particles stacking in the pellet. SEM micrograph had been captured to observe the presence of pores and agglomeration of particles in the sample produced.« less

Antioxidant activity of an invasive plant, Melastoma malabathricum and its potential as herbal tea product

NASA Astrophysics Data System (ADS)

Sari, N. M.; Kuspradini, H.; Amirta, R.; Kusuma, I. W.

2018-04-01

East Kalimantan possesses abundant biodiversity of tropical medicinal plant. Melastoma malabathricum (known locally as karamunting, senduduk) is an invasive plant along with other species in the family of Melastomataceae with traditional medicinal purposes. This research explored the potential of Karamunting (M. malabathricum) plant for its antioxidant activity and the potential as a material for herbal tea product. The plant was macerated to yield ethanolic extract, and at the same time plant powder was packed into tea bags and extracted with hot water to obtain the infused water. Antioxidant activity was evaluated by DPPH radical scavenging assay. The results showed that the ethanol extracts of plant samples displayed ability to inhibit DPPH free radical formation by 82% at 50 ppm concentration. Evaluation of the tea water extract showed that the highest inhibition obtained by leaves powder by 90% and fruit 88% at 1 minutes immersion time. This finding suggest that leaves and fruit of M. malabathricum plants display potential as herbal tea material having antioxidant activity if the safety aspect can be assured.

Very Hard Corrosion-Resistant Roll-Bonded Cr Coating on Mild Steel in Presence of Graphite

NASA Astrophysics Data System (ADS)

Kumar, Pankaj; Khara, S.; Shekhar, S.; Mondal, K.

2017-12-01

The present work discusses the development of very hard Cr and Cr-carbide coating by roll bonding of Cr powder on a mild steel followed by annealing at 800, 1000, 1100 and 1200 °C with and without the presence of graphite powder packing in argon environment. In addition, the effect of a roll skin pass of 5% prior to the application of coating was studied. The presence of graphite allows diffusion of both carbon and Cr in the mild steel substrate, leading to the formation of Cr-carbide on the outer surface, making the surface very hard (VHN 1800). Depending on the annealing temperature and processing condition, diffusion layer thickness of Cr is found to be in the range of 10-250 μm with Cr content of 12.5-15 wt.% across the diffusion layer. Excellent stable passivity of the coated surface is observed in 0.2 N H2SO4, which is comparable to a highly passivating 304 stainless steel, and very low corrosion rate of the coating is observed as compared to the substrate mild steel.

Temperature Dependence of the Structural Parameters in the Transformation of Aragonite to Calcite, as Determined from In Situ Synchrotron Powder X-ray-Diffratction Data

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

Antao, Sytle M.; Hassan, Ishmael; West Indies)

The temperature dependency of the crystal structure and the polymorphic transition of CaCO{sub 3} from aragonite to calcite were studied using Rietveld structure refinement and high-temperature in situ synchrotron powder X-ray-diffraction data at ambient pressure, P. The orthorhombic metastable aragonite at room P, space group Pmcn, transforms to trigonal calcite, space group R{bar 3}c, at about T{sub c} = 468 C. This transformation occurs rapidly; it starts at about 420 C and is completed by 500 C, an 80 C interval that took about 10 minutes using a heating rate of 8 C/min. Structurally, from aragonite to calcite, the distributionmore » of the Ca atom changes from approximately hexagonal to cubic close-packing. A 5.76% discontinuous increase in volume accompanies the reconstructive first-order transition. Besides the change in coordination of the Ca atom from nine to six from aragonite to calcite, the CO{sub 3} groups change by a 30{sup o} rotation across the transition.« less

Modeling Remineralization of Desalinated Water by Micronized Calcite Dissolution.

PubMed

Hasson, David; Fine, Larissa; Sagiv, Abraham; Semiat, Raphael; Shemer, Hilla

2017-11-07

A widely used process for remineralization of desalinated water consists of dissolution of calcite particles by flow of acidified desalinated water through a bed packed with millimeter-size calcite particles. An alternative process consists of calcite dissolution by slurry flow of micron-size calcite particles with acidified desalinated water. The objective of this investigation is to provide theoretical models enabling design of remineralization by calcite slurry dissolution with carbonic and sulfuric acids. Extensive experimental results are presented displaying the effects of acid concentration, slurry feed concentration, and dissolution contact time. The experimental data are shown to be in agreement within less than 10% with theoretical predictions based on the simplifying assumption that the slurry consists of uniform particles represented by the surface mean diameter of the powder. Agreement between theory and experiment is improved by 1-8% by taking into account the powder size distribution. Apart from the practical value of this work in providing a hitherto lacking design tool for a novel technology. The paper has the merit of being among the very few publications providing experimental confirmation to the theory describing reaction kinetics in a segregated flow system.

A study of ferromagnetic signals in SrTiO{sub 3} nanoparticles

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

Kovacs, P.; Des Roches, B.; Crandles, D. A.

It has been suggested that ferromagnetism may be a universal feature of nanoparticles related to particle size. We study this claim for the case of commercially produced SrTiO{sub 3} nanoparticles purchased from Alfa-Aesar. Both loosely-packed nanoparticle samples and pellets formed using uniaxial pressure were studied. Both loose and pressed samples were annealed in either air or in vacuum of 5×10{sup −6} Torr at 600, 800 and 1000°C. Then x-ray diffraction and SQUID measurements were made on the resulting samples. It was found that annealed loose powder samples always had a linear diamagnetic magnetization versus field response, while their pressed pelletmore » counterparts exhibit a ferromagnetic hysteresis component in addition to the linear diamagnetic signal. Williamson-Hall analysis reveals that the particle size in pressed pellet samples increases with annealing temperature but does not change significantly in loose powder samples. The main conclusion is that the act of pressing pellets in a die introduces a spurious ferromagnetic signal into SQUID measurements.« less

Thermal Measurements of Packed Copper Wire Enables Better Electric Motor

Science.gov Websites

transmittance characterization methods both parallel and perpendicular to the axis. A measurement of apparent from all three test methods indicated that the k_app of the packed copper wire was significantly higher methods for examining the thermal impact of new materials for winding structures relevant to motor

Enzymatic cascade bioreactor

DOEpatents

Simmons, Blake A.; Volponi, Joanne V.; Ingersoll, David; Walker, Andrew

2007-09-04

Disclosed is an apparatus and method for continuously converting sucrose to .beta.-D-glucose. The method comprises a three stage enzymatic reactor in which an aqueous solution of sucrose is first converted into a solution of fructose and .alpha.-D-glucose by passing it through a porous, packed column containing an inert media on which invertase is immobilized. This solution is then sent through a second packed column containing glucose isomerase and finally a third packed column containing mutarotase. Solution temperature and pH are adjusted to maximize glucose output.

Micro structrual characterization and analysis of ball milled silicon carbide

NASA Astrophysics Data System (ADS)

Madhusudan, B. M.; Raju, H. P.; Ghanaraja., S.

2018-04-01

Mechanical alloying has been one of the prominent methods of powder synthesis technique in solid state involving cyclic deformation, cold welding and fracturing of powder particles. Powder particles in this method are subjected to greater mechanical deformation due to the impact of ball-powder-ball and ball-powder-container collisions that occurs during mechanical alloying. Strain hardening and fracture of particles decreases the size of the particles and creates new surfaces. The objective of this Present work is to use ball milling of SiC powder for different duration of 5, 10, 15 and 20 hours by High energy planetary ball milling machine and to evaluate the effect of ball milling on SiC powder. Micro structural Studies using Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and EDAX has been investigated.

Synthesis method for ultrananocrystalline diamond in powder employing a coaxial arc plasma gun

NASA Astrophysics Data System (ADS)

Naragino, Hiroshi; Tominaga, Aki; Hanada, Kenji; Yoshitake, Tsuyoshi

2015-07-01

A new method that enables us to synthesize ultrananocrystalline diamond (UNCD) in powder is proposed. Highly energetic carbon species ejected from a graphite cathode of a coaxial arc plasma gun were provided on a quartz plate at a high density by repeated arc discharge in a compact vacuum chamber, and resultant films automatically peeled from the plate were aggregated and powdered. The grain size was easily controlled from 2.4 to 15.0 nm by changing the arc discharge energy. It was experimentally demonstrated that the proposed method is a new and promising method that enables us to synthesize UNCD in powder easily and controllably.

Aluminum and Other Coatings for the Passivation of Tritium Storage Vessels

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

Spencer, W.; Korinko, P.

Using a highly sensitive residual gas analyzer, the off-gassing of hydrogen, water, and hydrocarbons from surface-treated storage vessels containing deuterium was measured. The experimental storage vessels were compared to a low-off-gassing, electro-polished 304L canister. Alternative vessels were made out of aluminum, or were coatings on 304L steel. Coatings included powder pack aluminide, electro-plated aluminum, powder pack chromide, dense electro-plated chromium, copper plated, and copper plated with 25 and 50 percent nano-diamond. Vessels were loaded with low pressure deuterium to observe exchange with protium or hydrogen as observed with formation of HD and HDO. Off gas of D 2O or possiblemore » CD 4 was observed at mass 20. The main off-gas in all of the studies was H 2. The studies indicated that coatings required significant post-coating treatment to reduce off-gas and enhance the permeation barrier from gases likely added during the coating process. Dense packed aluminum coatings needed heating to drive off water. Electro-plated aluminum, chromium and copper coatings appeared to trap hydrogen from the plating process. Nano-diamond appeared to enhance the exchange rate with hydrogen off gas, and its coating process trapped significant amounts of hydrogen. Aluminum caused more protium exchange than chromium-treated surfaces. Aluminum coatings released more water, but pure aluminum vessels released small amounts of hydrogen, little water, and generally performed well. Chromium coating had residual hydrogen that was difficult to totally outgas but otherwise gave low residuals for water and hydrocarbons. Our studies indicated that simple coating of as received 304L metal will not adequately block hydrogen. The base vessel needs to be carefully out-gassed before applying a coating, and the coating process will likely add additional hydrogen that must be removed. Initial simple bake-out and leak checks up to 350° C for a few hours was found to be inadequate. All of the studies indicated that vessels needed several days of vacuum baking at 350-450° C to fully outgas the residual gases, which were mostly hydrogen. The current standard practice of out-gassing from ultra-clean, electro-polished 304L vessels with both vacuum bake-out and followed by an oxidative bake out to enhance the chromium surface performed the best in these studies.« less

Structural characterization of the packings of granular regular polygons.

PubMed

Wang, Chuncheng; Dong, Kejun; Yu, Aibing

2015-12-01

By using a recently developed method for discrete modeling of nonspherical particles, we simulate the random packings of granular regular polygons with three to 11 edges under gravity. The effects of shape and friction on the packing structures are investigated by various structural parameters, including packing fraction, the radial distribution function, coordination number, Voronoi tessellation, and bond-orientational order. We find that packing fraction is generally higher for geometrically nonfrustrated regular polygons, and can be increased by the increase of edge number and decrease of friction. The changes of packing fraction are linked with those of the microstructures, such as the variations of the translational and orientational orders and local configurations. In particular, the free areas of Voronoi tessellations (which are related to local packing fractions) can be described by log-normal distributions for all polygons. The quantitative analyses establish a clearer picture for the packings of regular polygons.

High-resolution of particle contacts via fluorophore exclusion in deep-imaging of jammed colloidal packings

NASA Astrophysics Data System (ADS)

Kyeyune-Nyombi, Eru; Morone, Flaviano; Liu, Wenwei; Li, Shuiqing; Gilchrist, M. Lane; Makse, Hernán A.

2018-01-01

Understanding the structural properties of random packings of jammed colloids requires an unprecedented high-resolution determination of the contact network providing mechanical stability to the packing. Here, we address the determination of the contact network by a novel strategy based on fluorophore signal exclusion of quantum dot nanoparticles from the contact points. We use fluorescence labeling schemes on particles inspired by biology and biointerface science in conjunction with fluorophore exclusion at the contact region. The method provides high-resolution contact network data that allows us to measure structural properties of the colloidal packing near marginal stability. We determine scaling laws of force distributions, soft modes, correlation functions, coordination number and free volume that define the universality class of jammed colloidal packings and can be compared with theoretical predictions. The contact detection method opens up further experimental testing at the interface of jamming and glass physics.

Packing Optimization of Sorbent Bed Containing Dissimilar and Irregular Shaped Media

NASA Technical Reports Server (NTRS)

Holland, Nathan; Guttromson, Jayleen; Piowaty, Hailey

2011-01-01

The Fire Cartridge is a packed bed air filter with two different and separate layers of media designed to provide respiratory protection from combustion products after a fire event on the International Space Station (ISS). The first layer of media is a carbon monoxide catalyst and the second layer of media is universal carbon. During development of Fire Cartridge prototypes, the two media beds were noticed to have shifted inside the cartridge. The movement of media within the cartridge can cause mixing of the bed layers, air voids, and channeling, which could cause preferential air flow and allow contaminants to pass through without removal. An optimally packed bed mitigates these risks and ensures effective removal of contaminants from the air. In order to optimally pack each layer, vertical, horizontal, and orbital agitations were investigated and a packed bulk density was calculated for each method. Packed bulk density must be calculated for each media type to accommodate variations in particle size, shape, and density. Additionally, the optimal vibration parameters must be re-evaluated for each batch of media due to variations in particle size distribution between batches. For this application it was determined that orbital vibrations achieve an optimal pack density and the two media layers can be packed by the same method. Another finding was media with a larger size distribution of particles achieve an optimal bed pack easier than media with a smaller size distribution of particles.

Preparation of nose for nasal endoscopy: cotton pledget packing versus topical spray. A prospective randomized blinded study.

PubMed

Mishra, Prasun; Kaushik, Maitri; Dehadaray, Arun; Qadri, Haris; Raichurkar, Annapurna; Seth, Tanvi

2013-01-01

During nasal endoscopy it is essential to have proper visualization of structures with minimal discomfort to patient and surgeon. For this it is essential that the nose is well prepared before the procedure. The main objective of the study is to compare and evaluate the efficacy of cotton pledget packing versus topical sprays in preparation of nose for nasal endoscopy. The method includes prospective randomized blinded study on 100 patients. Patients were randomly divided in two groups. In first group the nose was packed with 4% lignocaine with xylometazoline nasal drops and in the other group it was prepared with 10% lignocaine topical spray and xylometazoline nose drops. Following the procedure, patient and the surgeon were asked a pre-formed questionnaire to know their experience during endoscopy. It was observed the packing group required more preparatory time as compared to the spray group. The group which was packed had less discomfort, less pain while endoscopy. The visualization of structures was significantly better in the packed group. Eight patients in the packed group did have some mucosal bleed during the process of packing which was not seen in the spray group. Both methods of preparation have merits and demerits but in terms of discomfort, pain during procedure and visualization of structure, packing of nasal cavity with 4% lignocaine and xylometazoline drops is better than spraying of nose with 10% lignocaine and xylometazoline drops.

An amyloid-forming peptide from the yeast prion Sup35 reveals a dehydrated β-sheet structure for amyloid

PubMed Central

Balbirnie, Melinda; Grothe, Robert; Eisenberg, David S.

2001-01-01

X-ray diffraction and other biophysical tools reveal features of the atomic structure of an amyloid-like crystal. Sup35, a prion-like protein in yeast, forms fibrillar amyloid assemblies intrinsic to its prion function. We have identified a polar peptide from the N-terminal prion-determining domain of Sup35 that exhibits the amyloid properties of full-length Sup35, including cooperative kinetics of aggregation, fibril formation, binding of the dye Congo red, and the characteristic cross-β x-ray diffraction pattern. Microcrystals of this peptide also share the principal properties of the fibrillar amyloid, including a highly stable, β-sheet-rich structure and the binding of Congo red. The x-ray powder pattern of the microcrystals, extending to 0.9-Å resolution, yields the unit cell dimensions of the well-ordered structure. These dimensions restrict possible atomic models of this amyloid-like structure and demonstrate that it forms packed, parallel-stranded β-sheets. The unusually high density of the crystals shows that the packed β-sheets are dehydrated, despite the polar character of the side chains. These results suggest that amyloid is a highly intermolecularly bonded, dehydrated array of densely packed β-sheets. This dry β-sheet could form as Sup35 partially unfolds to expose the peptide, permitting it to hydrogen-bond to the same peptide of other Sup35 molecules. The implication is that amyloid-forming units may be short segments of proteins, exposed for interactions by partial unfolding. PMID:11226247

Synthesis and characterization of nanocrystalline Nd{sup 3+}-doped gadolinium scandium aluminum garnet powders by a gel-combustion method

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

Su, Jing, E-mail: zlj007@126.com; Miao, Ju-hong; Xu, Lin-hua

2012-07-15

Graphical abstract: The graph shows the emission spectra (λ{sub ex} = 808 nm) of 1 at.% Nd:GSAG powders sintered at different temperatures for 3 h. Compared with the powder sintered at 900 °C, the PL intensity of the powder sintered at 1000 °C decreased significantly. The changes in the PL intensity should mainly due to the crystallinity and dispersion of the powders. Highlights: ► We synthesized Nd:GSAG nano-powders by gel-combustion method successfully. ► We analyzed the structure and the morphology of the heat-treated products. ► We studied the optical characteristics of Nd:GSAG nano-powders. -- Abstract: Nd{sup 3+}-doped gadolinium scandium aluminummore » garnet (Nd:GSAG) precursor was synthesized by a gel combustion method using metal nitrates and citric acid as raw materials. The structure and morphology of the precursor and the sintered powders were studied by means of X-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM). The results showed that the precursor transformed into pure GSAG polycrystalline phase at about 800 °C, and the powders sintered at 800–1000 °C were well-dispersed with average particle sizes in the range of 30–80 nm. Optical properties of Nd:GSAG nano-powders were characterized by using photoluminescence spectroscopy. The highest photoluminescence intensity was achieved for the powder sintered at 900 °C.« less

Article and method for making an article

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

Lacy, Benjamin Paul; Schick, David Edward; Kottilingam, Srikanth Chandrudu

An article and a method for making shaped cooling holes in an article are provided. The method includes the steps of depositing a metal alloy powder to form an initial layer including at least one aperture, melting the metal alloy powder with a focused energy source to transform the powder layer to a sheet of metal alloy, sequentially depositing an additional layer of the metal alloy powder to form a layer including at least one aperture corresponding to the at least one aperture in the initial layer, melting the additional layer of the metal alloy powder with the focused energymore » source to increase the sheet thickness, and repeating the steps of sequentially depositing and melting the additional layers of metal alloy powder until a structure including at least one aperture having a predetermined profile is obtained. The structure is attached to a substrate to make the article.« less

Apparatus and method for determining solids circulation rate

DOEpatents

Ludlow, J Christopher [Morgantown, WV; Spenik, James L [Morgantown, WV

2012-02-14

The invention relates to a method of determining bed velocity and solids circulation rate in a standpipe experiencing a moving packed bed flow, such as the in the standpipe section of a circulating bed fluidized reactor The method utilizes in-situ measurement of differential pressure over known axial lengths of the standpipe in conjunction with in-situ gas velocity measurement for a novel application of Ergun equations allowing determination of standpipe void fraction and moving packed bed velocity. The method takes advantage of the moving packed bed property of constant void fraction in order to integrate measured parameters into simultaneous solution of Ergun-based equations and conservation of mass equations across multiple sections of the standpipe.

Measuring Patient Adherence to Malaria Treatment: A Comparison of Results from Self-Report and a Customised Electronic Monitoring Device

PubMed Central

Bruxvoort, Katia; Festo, Charles; Cairns, Matthew; Kalolella, Admirabilis; Mayaya, Frank; Kachur, S. Patrick; Schellenberg, David; Goodman, Catherine

2015-01-01

Background Self-report is the most common and feasible method for assessing patient adherence to medication, but can be prone to recall bias and social desirability bias. Most studies assessing adherence to artemisinin-based combination therapies (ACTs) have relied on self-report. In this study, we use a novel customised electronic monitoring device—termed smart blister packs—to examine the validity of self-reported adherence to artemether-lumefantrine (AL) in southern Tanzania. Methods Smart blister packs were designed to look identical to locally available AL blister packs and to record the date and time each tablet was removed from packaging. Patients obtaining AL at randomly selected health facilities and drug stores were followed up at home three days later and interviewed about each dose of AL taken. Blister packs were requested for pill count and extraction of smart blister pack data. Results Data on adherence from both self-report verified by pill count and smart blister packs were available for 696 of 1,204 patients. There was no difference between methods in the proportion of patients assessed to have completed treatment (64% and 67%, respectively). However, the percentage taking the correct number of pills for each dose at the correct times (timely completion) was higher by self-report than smart blister packs (37% vs. 24%; p<0.0001). By smart blister packs, 64% of patients completing treatment did not take the correct number of pills per dose or did not take each dose at the correct time interval. Conclusion Smart blister packs resulted in lower estimates of timely completion of AL and may be less prone to recall and social desirability bias. They may be useful when data on patterns of adherence are desirable to evaluate treatment outcomes. Improved methods of collecting self-reported data are needed to minimise bias and maximise comparability between studies. PMID:26214848

Secure hemostasis in transhiatal esophagectomy for esophageal cancer with gauze packing

PubMed Central

2012-01-01

Background Transhiatal esophagectomy for esophageal cancer implies blind manipulation of the intrathoracic esophagus. We report a secure hemostatic method with gauze packing in transhiatal esophagectomy. Methods The gauze-packing technique is utilized for hemostasis just after removal of the thoracic esophagus during transhiatal esophagectomy. After confirming cancer-free margins, the abdominal esophagus and cervical esophagus are transected. A vein stripper is inserted into the oral-side stump of the esophagus and led to exit from the abdominal-side stump of the esophagus. The vein stripper and the oral stump of the esophagus are affixed by silk thread. A polyester tape is then affixed to the vein stripper, as the polyester tape is left in the posterior mediastinum after removal of the esophagus toward the abdominal side. The polyester tape on the cervical side is ligated with gauze and the polyester tape is removed toward the abdominal side. The oral stump of gauze and new additional gauze are affixed. As the first gauze is pulled out from the abdominal side, the second gauze gets drawn from the cervical wound into the mediastinum. The posterior mediastinum is finally packed with gauze and possible bleeding at this site undergoes a complete astriction. The status of hemostasis with the gauze packing is checked by an observation of color and bloodstain on the gauze. Results Between January 2005 and February 2012, 13 consecutive patients with esophageal cancer underwent a transhiatal esophagectomy with the gauze-packing hemostatic technique. Hemostasis at the posterior mediastinum was performed successfully and quickly in all cases with this method, requiring up to four pieces of gauze for a complete hemostasis. Median required time for hemostasis was 1219 (range 1896 to 1293) seconds and estimated blood loss was 20.4 (range 15 to 25) ml during gauze packing. Conclusions Our technique could minimize bleeding after the removal of the thoracic esophagus. The gauze-packing method is a simple and easy technique for secure hemostasis when performing a transhiatal esophagectomy. PMID:23253358

Impregnation quality of shredded semipreg after compression moulding

NASA Astrophysics Data System (ADS)

Vincent, G.; Balakrishnan, V.; de Bruijn, T. A.; Wijskamp, S.; Abdul Rasheed, M. I.

2017-10-01

Manufacturing of thermoplastic composites (TPC) inherently generates scrap, mainly in the form of offcuts or rejected parts. The growth of TPC over recent decades has now reached a point where developing specific recycling solutions for TPC waste has become crucial. While looking at the various steps during which scrap is produced, the nesting of semipreg or prepreg appears to be critical. This work aims to develop a route for recycling semipreg offcuts, comprising shredding and compression moulding. This article focuses on an experimental study of the compression moulding step of carbon fibres reinforced PPS (C/PPS) to investigate the uniformity and impregnation quality of plates. These plates were realised in a picture frame while varying both the fibre volume content between 30% and 50% and the processing parameters. Visual inspection and cross-sectional microscopy were performed to assess the quality of each plate. As a first step, the influence of the type of added matrix (film, powder, pellets) and the type of pre-impregnation (film, powder) was studied. Stacking of polymer powder with shredded powder-coated semipreg gave the best impregnation quality. It was also shown that longer dwell time at melt leads to better consolidation quality. However, the difficulty in obtaining good impregnation comes from the disentangled shredded material, which is composed of three forms: semipreg flakes, dry bundles and pieces of matrix. When dry bundles reach the mould surfaces during the filling of the mould or when they are packed together, the consolidation cycle hardly impregnates them and they remain dry afterwards. Furthermore, large local variations of fibre fraction were noticed, resulting from a random mould filling. Therefore, the recycling solution for shredded semipreg is feasible when the fibre fraction is reduced but improvements on the part variability still have to be made.

Monoclinic β-Li2TiO3 nanocrystalline particles employing novel urea assisted solid state route: Synthesis, characterization and sintering behavior

NASA Astrophysics Data System (ADS)

Tripathi, Biranchi M.; Mohanty, Trupti; Prakash, Deep; Tyagi, A. K.; Sinha, P. K.

2017-07-01

Pure phase monoclinic nano-crystalline Li2TiO3 powder was synthesized by a novel urea assisted solid state synthesis method using readily available and economical precursors. A single phase and well crystalline Li2TiO3 powder has been obtained at slightly lower temperature (600-700 °C) and shorter duration (2 h) as compared to the conventional solid state method. The proposed method has significant advantages in comparison to other viable methods mainly in terms of phase purity, powder properties and sinterability. Analysis of chemical composition using inductively coupled plasma atomic emission spectroscopy (ICP-AES) shows no loss of lithium from Li2TiO3 in the proposed method. The emergence of monoclinic Li2TiO3 phase was confirmed by X-ray diffraction (XRD) pattern of as-synthesized powder. The crystallite size of Li2TiO3 powder was calculated to be in the range of 15-80 nm, which varied as a function of urea composition and temperature. The morphology of as-prepared Li2TiO3 powders was examined by scanning electron microscope (SEM). The effect of urea composition on phase and morphology was investigated so as to delineate the role of urea. Upon sintering at < 1000 °C temperature, the Li2TiO3 powder compact attained about 98% of the theoretical density with fine grained (grain size: 2-3 μm) microstructure. It indicates excellent sinter-ability of Li2TiO3 powder synthesized by the proposed method. The fine grained structure is desirable for better tritium breeding performance of Li2TiO3. Electrochemical impedance spectroscopy at variable temperature showed good electrical properties of Li2TiO3. The proposed method is simple, anticipated to be cost effective and convenient to realise for large scale production of phase pure nanocrystalline and having significantly enhanced sinter-ability Li2TiO3 powder.

[Properties and infiltration arts of machinable infiltration ceramic(MIC)].

PubMed

Yang, H; Xian, S; Liao, Y; Xue, Y; Chai, F

2000-06-01

The purpose of this study is to explore the infiltration arts of MIC and study the effects of different packing density of Al2O3 matrix on the properties of MIC. alpha-Al2O3 specimens were fabricated by pouring alpha-Al2O3 slip with different powder/liquid ratios(P/L = 3.5, 7.5, 10.5) into a mold, and subsequently pre-fired at 1160 degrees C for 6 hours to form Al2O3 matrix. The packing density of the matrices were measured. Infiltration concepts were introduced into this study by infiltrating molten mica micro-crystalline glass into the porous Al2O3 matrix at 1160 degrees C for 6 hours to form a continuous interpenetrating composite. The composite then underwent micro-crystallization by nucleating at 550 degrees C for 1 hour and crystallizing at 900 degrees C for 1 hour, which resulted in the MIC. Mechanical properties including three point flexural strength, elastic modulus, Vicker's hardness, indentation fracture toughness and Weibull's modulus of flexural strength were determined. Parameters of machinability(H/KIC)2 of MIC were calculated. XRD and SEM were employed to study its microstructure. The resulted matrices reached packing densities of 63%, 76%, 78% with P/L of 3.5, 7.5 and 10.5. The MIC attained high strength and good machinability after infiltration. Three-point flexural strength and indentation fracture toughness were 342, 431, 374 MPa and 4.05, 4.14, 5.02 MPa m1/2 for MIC with packing density of 63%, 76%, 78% separately. And parameters of machinability were 5.41, 6.84 and 7.39 respectively. Packing density of Al2O3 matrix significantly influenced the mechanical properties. Maximum properties were obtained with a matrix packing density of 75%(P/L = 7.5), with a Weibull's modulus of flexural strength of 6.8. Machinability decreased with the increase of P/L ratio. Micro-crystallizing treatment resulted in the formation of evenly distributed mica crystalline in the composite, which contributed to the high strength of this composite material. MIC is a new infiltrated ceramic with favorable strength and machinability which can satisfy the prosthodontic requirements as all ceramic crown and bridge materials, it also shows promising outlook for future developments and clinical usage.

Study on Raman spectral imaging method for simultaneous estimation of ingredients concentration in food powder

USDA-ARS?s Scientific Manuscript database

This study investigated the potential of point scan Raman spectral imaging method for estimation of different ingredients and chemical contaminant concentration in food powder. Food powder sample was prepared by mixing sugar, vanillin, melamine and non-dairy cream at 5 different concentrations in a ...

Adhesive and Cohesive Strength in FeB/Fe2B Systems

NASA Astrophysics Data System (ADS)

Meneses-Amador, A.; Blancas-Pérez, D.; Corpus-Mejía, R.; Rodríguez-Castro, G. A.; Martínez-Trinidad, J.; Jiménez-Tinoco, L. F.

2018-05-01

In this work, FeB/Fe2B systems were evaluated by the scratch test. The powder-pack boriding process was performed on the surface of AISI M2 steel. The mechanical parameters, such as yield stress and Young's modulus of the boride layer, were obtained by the instrumented indentation technique. Residual stresses produced on the boride layer were estimated by using the x-ray diffraction (XRD) technique. The scratch test was performed in order to evaluate the cohesive/adhesive strength of the FeB/Fe2B coating. In addition, a numerical evaluation of the scratch test on boride layers was performed by the finite element method. Maximum principal stresses were related to the failure mechanisms observed by the experimental scratch test. Shear stresses at the interfaces of the FeB/Fe2B/substrate system were also evaluated. Finally, the results obtained provide essential information about the effect of the layer thickness, the residual stresses, and the resilience modulus on the cohesive/adhesive strength in FeB/Fe2B systems.

WinPSSP : a revamp of the computer program PSSP and its performance solving the crystal structures of small organic compounds and solids of biological and pharmaceutical interest

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

Pagola, Silvina; Polymeros, Alekos; Kourkoumelis, Nikolaos

2017-02-01

The direct-space methods softwarePowder Structure Solution Program(PSSP) [Pagola & Stephens (2010).J. Appl. Cryst.43, 370–376] has been migrated to the Windows OS and the code has been optimized for fast runs.WinPSSPis a user-friendly graphical user interface that allows the input of preliminary crystal structure information, integrated intensities of the reflections and FWHM, the definition of structural parameters and a simulated annealing schedule, and the visualization of the calculated and experimental diffraction data overlaid for each individual solution. The solutions are reported as filename.cif files, which can be used to analyze packing motifs and chemical bonding, and to input the atomic coordinatesmore » into the Rietveld analysis softwareGSAS. WinPSSPperformance in straightforward crystal structure determinations has been evaluated using 18 molecular solids with 6–20 degrees of freedom. The free-distribution program as well as multimedia tutorials can be accessed at http://users.uoi.gr/nkourkou/winpssp/.« less

Intra-procedural Path-insensitve Grams (I-GRAMS) and Disassembly Based Features for Packer Tool Classification and Detection

DTIC Science & Technology

2012-06-14

executable file is packed is a critical step in software security. This research uses machine learning methods to build the Polymorphic and Non-Polymorphic...Packer Detection (PNPD) system that detects whether an executable is packed by either ASPack, UPX, Metasploit’s polymorphic msfencode, or is packed in...detect packed executables used in experiments. Overall, it is discovered i-grams provide the best results with accuracies above 99.5%, average true

Efficient process for previous metal recovery from cell membrane electrode assemblies

DOEpatents

Shore, Lawrence; Matlin, Ramail; Heinz, Robert

2010-05-04

A method is provided for recovering a catalytic element from a fuel cell membrane electrode assembly. The method includes grinding the membrane electrode assembly into a powder, extracting the catalytic element by forming a slurry comprising the powder and an acid leachate adapted to dissolve the catalytic element into a soluble salt, and separating the slurry into a depleted powder and a supernatant containing the catalytic element salt. The depleted powder is washed to remove any catalytic element salt retained within pores in the depleted powder and the catalytic element is purified from the salt.

Ceramic Technology for Advanced Heat Engines Project Semiannual Progress Report for Period October 1985 Through March 1986

DTIC Science & Technology

1986-08-01

materials (2.2 w/o and 3.0 w/o MgO). The other two batches (2.8 w/o and 3.1 w/o MgO), of higher purity, were made using E-10 zirconia powder from...CID) powders Two methods have been used for the coprecipitation of doped zirconia powders from solutions of chemical precursors. (4) Method I, for...of powder, approximate sample size 3.2 Kg (6.4 Kg for zirconia powder ); 342 3. Random selection of sample; 4. Partial drying of sample to reduce caking

How to Help Parents Pack Better Preschool Sack Lunches: Advice from Parents for Educators

ERIC Educational Resources Information Center

Sweitzer, Sara J.; Briley, Margaret E.; Roberts-Gray, Cindy; Hoelscher, Deanna M.; Staskel, Deanna M.; Almansour, Fawaz D.

2011-01-01

Objectives: This exploratory study obtained parent suggestions about messages and activities to guide parents to pack healthful sack lunches for preschool-aged children. Methods: A facilitator conducted group interviews using a modified nominal group technique with a convenience sample of parents who pack daily lunches for their children.…

State-of-charge inconsistency estimation of lithium-ion battery pack using mean-difference model and extended Kalman filter

NASA Astrophysics Data System (ADS)

Zheng, Yuejiu; Gao, Wenkai; Ouyang, Minggao; Lu, Languang; Zhou, Long; Han, Xuebing

2018-04-01

State-of-charge (SOC) inconsistency impacts the power, durability and safety of the battery pack. Therefore, it is necessary to measure the SOC inconsistency of the battery pack with good accuracy. We explore a novel method for modeling and estimating the SOC inconsistency of lithium-ion (Li-ion) battery pack with low computation effort. In this method, a second-order RC model is selected as the cell mean model (CMM) to represent the overall performance of the battery pack. A hypothetical Rint model is employed as the cell difference model (CDM) to evaluate the SOC difference. The parameters of mean-difference model (MDM) are identified with particle swarm optimization (PSO). Subsequently, the mean SOC and the cell SOC differences are estimated by using extended Kalman filter (EKF). Finally, we conduct an experiment on a small Li-ion battery pack with twelve cells connected in series. The results show that the evaluated SOC difference is capable of tracking the changing of actual value after a quick convergence.

The impact of structural packaging design on young adult smokers' perceptions of tobacco products.

PubMed

Borland, Ron; Savvas, Steven; Sharkie, Fiona; Moore, Karen

2013-03-01

To examine the extent that novel cigarette pack shapes and openings have on smokers' perceptions of those packs and the cigarettes contained within. Using a web-based survey, 160 young adult ever-smokers (18-29 years) were shown computer images of plain packaged cigarette packs in five different shapes. This was followed by packs illustrating five different methods of opening. Brand (prestige or budget) and size of the health warnings (30% or 70% warning size) were between-subject conditions. Respondents ranked packs on attractiveness, perceived quality of the cigarettes contained within and extent that the pack distracted from health warnings. Ratings of attractiveness and perceived quality were significantly associated in both substudies, but tendency to distract from warnings was more independent. Significant differences were found between the pack shapes on attractiveness, perceived quality and distraction from warnings. Standard, 2×10 and 4×5 packs were ranked less attractive than Bevelled and Rounded packs. 2×10 and 4×5 packs were also perceived as lower quality than Bevelled and Rounded packs. The Standard pack was less distracting to health warnings than all other shapes except the 2×10 pack. Pack openings were perceived as different on quality of cigarettes contained and extent of distraction to warnings. The Standard Flip-top was rated significantly lower in distracting from warnings than all other openings. Pack shape and pack opening affect ever-smokers' perceptions of the packs and the cigarettes they contain. This means that they have the potential to create appeal and differentiate products and thus should be regulated.

Determination of chloramphenicol in milk powder using liquid-liquid cartridge extraction (Chem Elut) and liquid chromatography-tandem mass spectrometry.

PubMed

Zawadzka, Iwona; Rodziewicz, Lech

2014-01-01

The European Union prohibits the use of chloramphenicol (CAP) as a veterinary drug in food-producing animals. Nevertheless, CAP have been detected in milk products (liquid milk and milk powder). Therefore, it is necessary to develop sensitive methods for determining CAP residues in milk powder. The aim of this study was to develop and validate a confirmatory method for determination of CAP in milk powder. Chloramphenicol was determined in milk powder using LC-ESI-MS/MS in negative mode. After fat removing milk powder sample was extracted/cleaned-up with a Chem Elut extraction cartridge. Separation was achieved on a Phenomenex Luna C-18 column with acetonitrile-water as a mobile phase. The mass spectrometer was operated in multiple reaction monitoring mode (MRM). Four transitions were monitored m/z 321→152, 321→194, 321→257 (CAP) and 326→157 (IS CAP-d5). Linearity, accuracy, precision, decision limit (CCa), detection capability (CCb) and ruggedness were determined for m/z 321→152. The mean relative recoveries (inter standard-corrected) of CAP from whole milk powder spiked at levels 0.1, 0.2, 0.3 and 0.6 mg/kg were in the range 95 - 103%. Relative standard deviation (RSD%) of recoveries at all spiked levels were less than 14%. RSDs within-laboratory reproducibility calculated at fortification of 0.3 mg/kg was less than 16%. CCa and CCb were below 0.1 mg/kg. The developed LC-MS/MS method allows the determination of CAP in milk powder. The method was validated according to the Commission Decision No. 2002/657/EC requirements. This method can be applied to determination CAP in whole and skim milk powder.

How does increasingly plainer cigarette packaging influence adult smokers' perceptions about brand image? An experimental study.

PubMed

Wakefield, M A; Germain, D; Durkin, S J

2008-12-01

Cigarette packaging is a key marketing strategy for promoting brand image. Plain packaging has been proposed to limit brand image, but tobacco companies would resist removal of branding design elements. A 3 (brand types) x 4 (degree of plain packaging) between-subject experimental design was used, using an internet online method, to expose 813 adult Australian smokers to one randomly selected cigarette pack, after which respondents completed ratings of the pack. Compared with current cigarette packs with full branding, cigarette packs that displayed progressively fewer branding design elements were perceived increasingly unfavourably in terms of smokers' appraisals of the packs, the smokers who might smoke such packs, and the inferred experience of smoking a cigarette from these packs. For example, cardboard brown packs with the number of enclosed cigarettes displayed on the front of the pack and featuring only the brand name in small standard font at the bottom of the pack face were rated as significantly less attractive and popular than original branded packs. Smokers of these plain packs were rated as significantly less trendy/stylish, less sociable/outgoing and less mature than smokers of the original pack. Compared with original packs, smokers inferred that cigarettes from these plain packs would be less rich in tobacco, less satisfying and of lower quality tobacco. Plain packaging policies that remove most brand design elements are likely to be most successful in removing cigarette brand image associations.

3D molecular models of whole HIV-1 virions generated with cellPACK

PubMed Central

Goodsell, David S.; Autin, Ludovic; Forli, Stefano; Sanner, Michel F.; Olson, Arthur J.

2014-01-01

As knowledge of individual biological processes grows, it becomes increasingly useful to frame new findings within their larger biological contexts in order to generate new systems-scale hypotheses. This report highlights two major iterations of a whole virus model of HIV-1, generated with the cellPACK software. cellPACK integrates structural and systems biology data with packing algorithms to assemble comprehensive 3D models of cell-scale structures in molecular detail. This report describes the biological data, modeling parameters and cellPACK methods used to specify and construct editable models for HIV-1. Anticipating that cellPACK interfaces under development will enable researchers from diverse backgrounds to critique and improve the biological models, we discuss how cellPACK can be used as a framework to unify different types of data across all scales of biology. PMID:25253262

Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

DOEpatents

Zhamu, Aruna; Shi, Jinjun; Guo, Jiusheng; Jang, Bor Z

2014-04-08

A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.

Ceramic oxide powders and the formation thereof

DOEpatents

Katz, Joseph L.; Hung, Cheng-Hung

1993-01-01

Ceramic oxide powders and a method for their preparation. Ceramic oxide powders are obtained using a flame process whereby two or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein said precursors are converted into ceramic oxide powders. The morphology, particle size, and crystalline form of the ceramic oxide powders are determined by process conditions.

Cleaning and modification of intraorally contaminated titanium discs with calcium phosphate powder abrasive treatment.

PubMed

Tastepe, Ceylin S; Liu, Yuelian; Visscher, Corine M; Wismeijer, Daniel

2013-11-01

The aim of this study was to evaluate the cleaning efficiency on intraorally contaminated titanium discs by using calcium phosphate and air powder abrasive (APA) treatment. The modification of titanium surface (SLA) was evaluated and compared with the conventional air powder abrasive methods and phosphoric acid. This treatment modality might give new perspectives for peri-implant surface treatment. A total of 36 SLA surface titanium discs were kept in the human mouth for 48 h by 14 volunteers. The intraorally contaminated discs were stained with erythrosine dye to make the biofilm visible. Discs were randomly assigned to one of the six groups: APA without powder-only water and air (Control). APA with Hydroxylapatite (HA). APA with Hydroxylapatite and Calcium Phosphate (HA + TCP). APA with Titanium Dioxide (TiO2). APA with EMS Soft Subgingival powder (EMS). Phosphoric Acid. Light microscope photos were taken during the treatment. Following the cleaning, the residual biofilm, surface changes, and surface chemical content were evaluated using Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS). A systematic random sampling protocol and a point counting method were applied for the quantitative evaluation of the remaining biofilm. Multiple comparisons within and between groups are performed by Kruskall Wallis test and if significant Mann-Whitney U-test as post hoc testing is applied. The significance level was P < 0.05. All methods with the exception of phosphoric acid could decrease the initial amount of biofilm significantly. Among all air powder abrasive treatments, the HA + TCP group showed the best results with 99% biofilm removal, followed by HA and EMS powders. The cleaning method caused minimal changes to the surface structure. With the exception of the control group, all air powder applications caused sharp edges around the grooves in the implant surface to be rounded. TiO2 powder caused less change than HA and HA + TCP. Phosphoric acid did not cause a visible surface change on the SEM photos. Powder particles remnants were observed on and impacted in the titanium surface. In the HA and HA + TCP group, a Ca content was observed varying between 2% and 5%. In the control group, saliva and biofilm-related elements were observed. Using the air powder abrasive method with calcium phosphate powders on contaminated titanium discs, an efficient implant cleaning and surface modification can be achieved. This method should be further improved as it has possible potential to be used as an implant surface treatment method for implants involved with peri-implantitis. © 2012 John Wiley & Sons A/S.

A material-sparing method for assessment of powder deformation characteristics using data collected during a single compression-decompression cycle.

PubMed

Katz, Jeffrey M; Roopwani, Rahul; Buckner, Ira S

2013-10-01

Compressibility profiles, or functions of solid fraction versus applied pressure, are used to provide insight into the fundamental mechanical behavior of powders during compaction. These functions, collected during compression (in-die) or post ejection (out-of-die), indicate the amount of pressure that a given powder formulation requires to be compressed to a given density or thickness. To take advantage of the benefits offered by both methods, the data collected in-die during a single compression-decompression cycle will be used to generate the equivalent of a complete out-of-die compressibility profile that has been corrected for both elastic and viscoelastic recovery of the powder. This method has been found to be both a precise and accurate means of evaluating out-of-die compressibility for four common tableting excipients. Using this method, a comprehensive characterization of powder compaction behavior, specifically in relation to plastic/brittle, elastic and viscoelastic deformation, can be obtained. Not only is the method computationally simple, but it is also material-sparing. The ability to characterize powder compressibility using this approach can improve productivity and streamline tablet development studies. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

Study on Antibacterial Property of PMMA Denture Base Materials with Negative Ion Powder

NASA Astrophysics Data System (ADS)

Liu, Meitian; Zhang, Xiaohui; Zhang, Jingting; Zheng, Qian; Liu, Bin

2018-01-01

To prepare the denture base resin with negative ion powder and evaluate the antibacterial effect of denture base resin with different contents of negative ion powder for clinical application. Method: Denture base material with negative ion powder was prepared by in-situ polymerization method, 50mm * 50mm * 2mm standard samples were prepared respectively. Antibacterial properties were tested with the film contact method. Experimental bacteria: Staphylococcus aureus (ATCC6538), Escherichia coli (ATCC8099).Result:With the increase of the amount of negative ion powder, the inhibition rate of the composite material to Escherichia coli and Staphylococcus aureus showed an increasing trend, and the number of residual bacteria on the surface showed a decreasing trend. When the content of negative ion powder was 2%, the composite material Staphylococcus aureus and Escherichia coli were 77.9% and 80.3% respectively. When the addition ratio was 5%, the bactericidal rate of the composite material to Staphylococcus aureus and Escherichia coli reached 98.2% and 99.1% respectively. Conclusion: The denture base material containing more than 2%wt negative ion powder has strong sterilization.

Understanding the General Packing Rearrangements Required for Successful Template Based Modeling of Protein Structure from a CASP Experiment

PubMed Central

Day, Ryan; Joo, Hyun; Chavan, Archana; Lennox, Kristin P.; Chen, Ann; Dahl, David B.; Vannucci, Marina; Tsai, Jerry W.

2012-01-01

As an alternative to the common template based protein structure prediction methods based on main-chain position, a novel side-chain centric approach has been developed. Together with a Bayesian loop modeling procedure and a combination scoring function, the Stone Soup algorithm was applied to the CASP9 set of template based modeling targets. Although the method did not generate as large of perturbations to the template structures as necessary, the analysis of the results gives unique insights into the differences in packing between the target structures and their templates. Considerable variation in packing is found between target and template structures even when the structures are close, and this variation is found due to 2 and 3 body packing interactions. Outside the inherent restrictions in packing representation of the PDB, the first steps in correctly defining those regions of variable packing have been mapped primarily to local interactions, as the packing at the secondary and tertiary structure are largely conserved. Of the scoring functions used, a loop scoring function based on water structure exhibited some promise for discrimination. These results present a clear structural path for further development of a side-chain centered approach to template based modeling. PMID:23266765

Understanding the general packing rearrangements required for successful template based modeling of protein structure from a CASP experiment.

PubMed

Day, Ryan; Joo, Hyun; Chavan, Archana C; Lennox, Kristin P; Chen, Y Ann; Dahl, David B; Vannucci, Marina; Tsai, Jerry W

2013-02-01

As an alternative to the common template based protein structure prediction methods based on main-chain position, a novel side-chain centric approach has been developed. Together with a Bayesian loop modeling procedure and a combination scoring function, the Stone Soup algorithm was applied to the CASP9 set of template based modeling targets. Although the method did not generate as large of perturbations to the template structures as necessary, the analysis of the results gives unique insights into the differences in packing between the target structures and their templates. Considerable variation in packing is found between target and template structures even when the structures are close, and this variation is found due to 2 and 3 body packing interactions. Outside the inherent restrictions in packing representation of the PDB, the first steps in correctly defining those regions of variable packing have been mapped primarily to local interactions, as the packing at the secondary and tertiary structure are largely conserved. Of the scoring functions used, a loop scoring function based on water structure exhibited some promise for discrimination. These results present a clear structural path for further development of a side-chain centered approach to template based modeling. Copyright © 2012 Elsevier Ltd. All rights reserved.

Random sphere packing model of heterogeneous propellants

NASA Astrophysics Data System (ADS)

Kochevets, Sergei Victorovich

It is well recognized that combustion of heterogeneous propellants is strongly dependent on the propellant morphology. Recent developments in computing systems make it possible to start three-dimensional modeling of heterogeneous propellant combustion. A key component of such large scale computations is a realistic model of industrial propellants which retains the true morphology---a goal never achieved before. The research presented develops the Random Sphere Packing Model of heterogeneous propellants and generates numerical samples of actual industrial propellants. This is done by developing a sphere packing algorithm which randomly packs a large number of spheres with a polydisperse size distribution within a rectangular domain. First, the packing code is developed, optimized for performance, and parallelized using the OpenMP shared memory architecture. Second, the morphology and packing fraction of two simple cases of unimodal and bimodal packs are investigated computationally and analytically. It is shown that both the Loose Random Packing and Dense Random Packing limits are not well defined and the growth rate of the spheres is identified as the key parameter controlling the efficiency of the packing. For a properly chosen growth rate, computational results are found to be in excellent agreement with experimental data. Third, two strategies are developed to define numerical samples of polydisperse heterogeneous propellants: the Deterministic Strategy and the Random Selection Strategy. Using these strategies, numerical samples of industrial propellants are generated. The packing fraction is investigated and it is shown that the experimental values of the packing fraction can be achieved computationally. It is strongly believed that this Random Sphere Packing Model of propellants is a major step forward in the realistic computational modeling of heterogeneous propellant of combustion. In addition, a method of analysis of the morphology of heterogeneous propellants is developed which uses the concept of multi-point correlation functions. A set of intrinsic length scales of local density fluctuations in random heterogeneous propellants is identified by performing a Monte-Carlo study of the correlation functions. This method of analysis shows great promise for understanding the origins of the combustion instability of heterogeneous propellants, and is believed to become a valuable tool for the development of safe and reliable rocket engines.

Atomization methods for forming magnet powders

DOEpatents

Sellers, Charles H.; Branagan, Daniel J.; Hyde, Timothy A.

2000-01-01

The invention encompasses methods of utilizing atomization, methods for forming magnet powders, methods for forming magnets, and methods for forming bonded magnets. The invention further encompasses methods for simulating atomization conditions. In one aspect, the invention includes an atomization method for forming a magnet powder comprising: a) forming a melt comprising R.sub.2.1 Q.sub.13.9 B.sub.1, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; b) atomizing the melt to form generally spherical alloy powder granules having an internal structure comprising at least one of a substantially amorphous phase or a substantially nanocrystalline phase; and c) heat treating the alloy powder to increase an energy product of the alloy powder; after the heat treatment, the alloy powder comprising an energy product of at least 10 MGOe. In another aspect, the invention includes a magnet comprising R, Q, B, Z and X, wherein R is a rare earth element; X is an element selected from the group consisting of carbon, nitrogen, oxygen and mixtures thereof; Q is an element selected from the group consisting of Fe, Co and mixtures thereof; and Z is an element selected from the group consisting of Ti, Zr, Hf and mixtures thereof; the magnet comprising an internal structure comprising R.sub.2.1 Q.sub.13.9 B.sub.1.

[Impact of directly compressed auxiliary materials on powder property of fermented cordyceps powder].

PubMed

Chen, Li-Hua; Yue, Guo-Chao; Guan, Yong-Mei; Yang, Ming; Zhu, Wei-Feng

2014-01-01

To investigate such physical indexes as hygroscopicity, angle of repose, bulk density, fillibility of compression of mixed powder of directly compressed auxiliary materials and fermented cordyceps powder by using micromeritic study methods. The results showed that spray-dried lactose Flowlac100 and microcrystalline cellulose Avicel PH102 had better effect in liquidity and compressibility on fermented cordyceps powder than pregelatinized starch. The study on the impact of directly compressed auxiliary materials on the powder property of fermented cordyceps powder had guiding significant to the research of fermented cordyceps powder tablets, and could provide basis for the development of fermented cordyceps powder tablets.

PLUTONIUM-HYDROGEN REACTION PRODUCT, METHOD OF PREPARING SAME AND PLUTONIUM POWDER THEREFROM

DOEpatents

Fried, S.; Baumbach, H.L.

1959-12-01

A process is described for forming plutonlum hydride powder by reacting hydrogen with massive plutonium metal at room temperature and the product obtained. The plutonium hydride powder can be converted to plutonium powder by heating to above 200 deg C.

Straightforward fabrication of black nano silica dusting powder for latent fingerprint imaging

NASA Astrophysics Data System (ADS)

Komalasari, Isna; Krismastuti, Fransiska Sri Herwahyu; Elishian, Christine; Handayani, Eka Mardika; Nugraha, Willy Cahya; Ketrin, Rosi

2017-11-01

Imaging of latent fingerprint pattern (aka fingermark) is one of the most important and accurate detection methods in forensic investigation because of the characteristic of individual fingerprint. This detection technique relies on the mechanical adherence of fingerprint powder to the moisture and oily component of the skin left on the surface. The particle size of fingerprint powder is one of the critical parameter to obtain excellent fingerprint image. This study develops a simple, cheap and straightforward method to fabricate Nano size black dusting fingerprint powder based on Nano silica and applies the powder to visualize latent fingerprint. The nanostructured silica was prepared from tetraethoxysilane (TEOS) and then modified with Nano carbon, methylene blue and sodium acetate to color the powder. Finally, as a proof-of-principle, the ability of this black Nano silica dusting powder to image latent fingerprint is successfully demonstrated and the results show that this fingerprint powder provides clearer fingerprint pattern compared to the commercial one highlighting the potential application of the nanostructured silica in forensic science.

Optimum process design of packed bed type thermal storage systems and other applications

DOEpatents

Bindra, Hitesh; Bueno, Pablo

2016-10-25

Methods and systems for optimizing the process of heat and/or mass transfer operations in packed beds and embodiments of applications of the methods are disclosed herein below. In one instance, the method results in the profile of the quantity representative of the heat and/or mass transfer operation having a propagating substantially sharp front.

Ceramic oxide powders and the formation thereof

DOEpatents

Katz, J.L.; Chenghung Hung.

1993-12-07

Ceramic oxide powders and a method for their preparation. Ceramic oxide powders are obtained using a flame process whereby two or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein said precursors are converted into ceramic oxide powders. The morphology, particle size, and crystalline form of the ceramic oxide powders are determined by process conditions. 14 figures.

Application of the Booth-Kautzmann method for the determination of N-2 packing leakage

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

Burkhart, D.M.; Milton, J.W.; Fawcett, S.T.

1995-06-01

To accurately determine turbine cycle heat rate, leakage past the N-2 steam seal packing must be determined on turbines with both HP and IP turbines contained within a common high pressure casing. N-2 packing leakage can be determined by the Booth-Kautzmann Method with instrumentation commonly used to determine the HP and IP turbine efficiency. The only additional requirements are changes to the main steam and/or hot reheat steam conditions. This paper discusses the actual test results using the Booth-Kautzmann test procedure on three natural gas fired units. The test results demonstrate the added advantage of having at least three N-2more » test runs, stability requirements for repeatable test runs and test procedures used to determine leakage results. Discussion of the sensitivity of the assumed N-2 enthalpy are also addressed. Utilizing Martins Formula with a series of N-2 Leakage test runs is shown to be a leakage prediction tool and a packing clearance approximation tool. It is concluded that the Booth-Kautzmann Method for determination of N-2 packing leakage should be utilized whenever HP and Ip turbine efficiency is determined. The two or three additional hours invested in the test runs is well worth the information gained on the performance of the N-2 packing.« less

Time resolved fluorescence of cow and goat milk powder

NASA Astrophysics Data System (ADS)

Brandao, Mariana P.; de Carvalho dos Anjos, Virgílio; Bell., Maria José V.

2017-01-01

Milk powder is an international dairy commodity. Goat and cow milk powders are significant sources of nutrients and the investigation of the authenticity and classification of milk powder is particularly important. The use of time-resolved fluorescence techniques to distinguish chemical composition and structure modifications could assist develop a portable and non-destructive methodology to perform milk powder classification and determine composition. This study goal is to differentiate milk powder samples from cows and goats using fluorescence lifetimes. The samples were excited at 315 nm and the fluorescence intensity decay registered at 468 nm. We observed fluorescence lifetimes of 1.5 ± 0.3, 6.4 ± 0.4 and 18.7 ± 2.5 ns for goat milk powder; and 1.7 ± 0.3, 6.9 ± 0.2 and 29.9 ± 1.6 ns for cow's milk powder. We discriminate goat and cow powder milk by analysis of variance using Fisher's method. In addition, we employed quadratic discriminant analysis to differentiate the milk samples with accuracy of 100%. Our results suggest that time-resolved fluorescence can provide a new method to the analysis of powder milk and its composition.

Compaction Behavior of Granular Materials

NASA Astrophysics Data System (ADS)

Endicott, Mark R.; Kenkre, V. M.; Glass, S. Jill; Hurd, Alan J.

1996-03-01

We report the results of our recent study of compaction of granular materials. A theoretical model is developed for the description of the compaction of granular materials exemplified by granulated ceramic powders. Its predictions are compared to observations of uniaxial compaction tests of ceramic granules of PMN-PT, spray dried alumina and rutile. The theoretical model employs a volume-based statistical mechanics treatment and an activation analogy. Results of a computer simulation of random packing of discs in two dimensions are also reported. The effect of type of particle size distribution and other parameters of that distribution on the calculated quantities are discussed. We examine the implications of the results of the simulation for the theoretical model.

A synthesis of fluorescent starch based on carbon nanoparticles for fingerprints detection

NASA Astrophysics Data System (ADS)

Li, Hongren; Guo, Xingjia; Liu, Jun; Li, Feng

2016-10-01

A pyrolysis method for synthesizing carbon nanoparticles (CNPs) were developed by using malic acid and ammonium oxalate as raw materials. The incorporation of a minor amount of carbon nanoparticles into starch powder imparts remarkable color-tunability. Based on this phenomenon, an environment friendly fluorescent starch powder for detecting latent fingerprints in non-porous surfaces was prepared. The fingerprints on different non-porous surfaces developed with this powder showed very good fluorescent images under ultraviolet excitation. The method using fluorescent starch powder as fluorescent marks is simple, rapid and green. Experimental results illustrated the effectiveness of proposed methods, enabling its practical applications in forensic sciences.

Processing and Characterization of Sol-Gel Cerium Oxide Microspheres

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

McClure, Zachary D.; Padilla Cintron, Cristina

Of interest to space exploration and power generation, Radioisotope Thermoelectric Generators (RTGs) can provide long-term power to remote electronic systems without the need for refueling or replacement. Plutonium-238 (Pu-238) remains one of the more promising materials for thermoelectric power generation due to its high power density, long half-life, and low gamma emissions. Traditional methods for processing Pu-238 include ball milling irregular precipitated powders before pressing and sintering into a dense pellet. The resulting submicron particulates of Pu-238 quickly accumulate and contaminate glove boxes. An alternative and dust-free method for Pu-238 processing is internal gelation via sol-gel techniques. Sol-gel methodology createsmore » monodisperse and uniform microspheres that can be packed and pressed into a pellet. For this study cerium oxide microspheres were produced as a surrogate to Pu-238. The similar electronic orbitals between cerium and plutonium make cerium an ideal choice for non-radioactive work. Before the microspheres can be sintered and pressed they must be washed to remove the processing oil and any unreacted substituents. An investigation was performed on the washing step to find an appropriate wash solution that reduced waste and flammable risk. Cerium oxide microspheres were processed, washed, and characterized to determine the effectiveness of the new wash solution.« less

Microstructure and Mechanical Properties of Ti-6Al-4V Fabricated by Selective Laser Melting of Powder Produced by Granulation-Sintering-Deoxygenation Method

NASA Astrophysics Data System (ADS)

Sun, Pei; Fang, Z. Zak; Zhang, Ying; Xia, Yang

2017-12-01

Commercial spherical Ti powders for additive manufacturing applications are produced today by melt-atomization methods at relatively high costs. A meltless production method, called granulation-sintering-deoxygenation (GSD), was developed recently to produce spherical Ti alloy powder at a significantly reduced cost. In this new process, fine hydrogenated Ti particles are agglomerated to form spherical granules, which are then sintered to dense spherical particles. After sintering, the solid fully dense spherical Ti alloy particles are deoxygenated using novel low-temperature deoxygenation processes with either Mg or Ca. This technical communication presents results of 3D printing using GSD powder and the selective laser melting (SLM) technique. The results showed that tensile properties of parts fabricated from spherical GSD Ti-6Al-4V powder by SLM are comparable with typical mill-annealed Ti-6Al-4V. The characteristics of 3D printed Ti-6Al-4V from GSD powder are also compared with that of commercial materials.

Effects of fabrication methods on spin relaxation and crystallite quality in Tm-doped ? powders studied using spectral hole burning

NASA Astrophysics Data System (ADS)

Lutz, Thomas; Veissier, Lucile; Thiel, Charles W.; Woodburn, Philip J. T.; Cone, Rufus L.; Barclay, Paul E.; Tittel, Wolfgang

2016-01-01

High-quality rare-earth-ion (REI) doped materials are a prerequisite for many applications such as quantum memories, ultra-high-resolution optical spectrum analyzers and information processing. Compared to bulk materials, REI doped powders offer low-cost fabrication and a greater range of accessible material systems. Here we show that crystal properties, such as nuclear spin lifetime, are strongly affected by mechanical treatment, and that spectral hole burning can serve as a sensitive method to characterize the quality of REI doped powders. We focus on the specific case of thulium doped ? (Tm:YAG). Different methods for obtaining the powders are compared and the influence of annealing on the spectroscopic quality of powders is investigated on a few examples. We conclude that annealing can reverse some detrimental effects of powder fabrication and, in certain cases, the properties of the bulk material can be reached. Our results may be applicable to other impurities and other crystals, including color centers in nano-structured diamond.

A new powder production route for transparent spinel windows: powder synthesis and window properties

NASA Astrophysics Data System (ADS)

Cook, Ronald; Kochis, Michael; Reimanis, Ivar; Kleebe, Hans-Joachim

2005-05-01

Spinel powders for the production of transparent polycrystalline ceramic windows have been produced using a number of traditional ceramic and sol-gel methods. We have demonstrated that magnesium aluminate spinel powders produced from the reaction of organo-magnesium compounds with surface modified boehmite precursors can be used to produce high quality transparent spinel parts. The new powder production method allows fine control over the starting particle size, size distribution, purity and stoichiometry. The new process involves formation of a boehmite sol-gel from the hydrolysis of aluminum alkoxides followed by surface modification of the boehmite nanoparticles using carboxylic acids. The resulting surface modified boehmite nanoparticles can then be metal exchanged at room temperature with magnesium acetylacetonate to make a precursor powder that is readily transformed into pure phase spinel.

Pressurized Anneal of Consolidated Powders

NASA Technical Reports Server (NTRS)

Nemir, David Charles (Inventor); Rubio, Edward S. (Inventor); Beck, Jan Bastian (Inventor)

2017-01-01

Systems and methods for producing a dense, well bonded solid material from a powder may include consolidating the powder utilizing any suitable consolidation method, such as explosive shockwave consolidation. The systems and methods may also include a post-processing thermal treatment that exploits a mismatch between the coefficients of thermal expansion between the consolidated material and the container. Due to the mismatch in the coefficients, internal pressure on the consolidated material during the heat treatment may be increased.

Effect of different packaging methods and storage temperature on microbiological and physicochemical quality characteristics of meatball.

PubMed

Yilmaz, I; Demirci, M

2010-06-01

The objective of this research was to determine physicochemical changes and microbiological quality of the different packaged meatball samples. Meatball samples in polystyrene tray were closed with polyethylene film (PS packs), vacuumed and modified atmosphere packaged, (MAP) (65% N(2), 35% CO(2)), and held under refrigerated display (4 °C) for 8, 16 and 16 days for PS packs, vacuum and MAP, respectively. Microbial load, free fatty acids and thiobarbituric acid values of the samples tended to increase with storage time. Bacteria counts of the raw meatball samples increased 2 log cycles at the end of storage compared with initial values. Meatball samples can be stored without any microbiological problem for 7 days at 4 °C. Results from this study suggested that shelf-life assigned to modified-MAP and vacuum-packed meatballs may be appropriate. Meatball samples underwent physical deformation when they were packed before vacuum process. With these negative factors considered, MAP is superior to other two packs methods.

Method and system for simulating heat and mass transfer in cooling towers

DOEpatents

Bharathan, Desikan; Hassani, A. Vahab

1997-01-01

The present invention is a system and method for simulating the performance of a cooling tower. More precisely, the simulator of the present invention predicts values related to the heat and mass transfer from a liquid (e.g., water) to a gas (e.g., air) when provided with input data related to a cooling tower design. In particular, the simulator accepts input data regarding: (a) cooling tower site environmental characteristics; (b) cooling tower operational characteristics; and (c) geometric characteristics of the packing used to increase the surface area within the cooling tower upon which the heat and mass transfer interactions occur. In providing such performance predictions, the simulator performs computations related to the physics of heat and mass transfer within the packing. Thus, instead of relying solely on trial and error wherein various packing geometries are tested during construction of the cooling tower, the packing geometries for a proposed cooling tower can be simulated for use in selecting a desired packing geometry for the cooling tower.

Process for microwave sintering boron carbide

DOEpatents

Holcombe, C.E.; Morrow, M.S.

1993-10-12

A method of microwave sintering boron carbide comprises leaching boron carbide powder with an aqueous solution of nitric acid to form a leached boron carbide powder. The leached boron carbide powder is coated with a glassy carbon precursor to form a coated boron carbide powder. The coated boron carbide powder is consolidated in an enclosure of boron nitride particles coated with a layer of glassy carbon within a container for microwave heating to form an enclosed coated boron carbide powder. The enclosed coated boron carbide powder is sintered within the container for microwave heating with microwave energy.

Process for microwave sintering boron carbide

DOEpatents

Holcombe, Cressie E.; Morrow, Marvin S.

1993-01-01

A method of microwave sintering boron carbide comprises leaching boron carbide powder with an aqueous solution of nitric acid to form a leached boron carbide powder. The leached boron carbide powder is coated with a glassy carbon precursor to form a coated boron carbide powder. The coated boron carbide powder is consolidated in an enclosure of boron nitride particles coated with a layer of glassy carbon within a container for microwave heating to form an enclosed coated boron carbide powder. The enclosed coated boron carbide powder is sintered within the container for microwave heating with microwave energy.

Modeling for Ultrasonic Health Monitoring of Foams with Embedded Sensors

NASA Technical Reports Server (NTRS)

Wang, L.; Rokhlin, S. I.; Rokhlin, Stanislav, I.

2005-01-01

In this report analytical and numerical methods are proposed to estimate the effective elastic properties of regular and random open-cell foams. The methods are based on the principle of minimum energy and on structural beam models. The analytical solutions are obtained using symbolic processing software. The microstructure of the random foam is simulated using Voronoi tessellation together with a rate-dependent random close-packing algorithm. The statistics of the geometrical properties of random foams corresponding to different packing fractions have been studied. The effects of the packing fraction on elastic properties of the foams have been investigated by decomposing the compliance into bending and axial compliance components. It is shown that the bending compliance increases and the axial compliance decreases when the packing fraction increases. Keywords: Foam; Elastic properties; Finite element; Randomness

Slip casting nano-particle powders for making transparent ceramics

DOEpatents

Kuntz, Joshua D [Livermore, CA; Soules, Thomas F [Livermore, CA; Landingham, Richard Lee [Livermore, CA; Hollingsworth, Joel P [Oakland, CA

2011-04-12

A method of making a transparent ceramic including the steps of providing nano-ceramic powders in a processed or unprocessed form, mixing the powders with de-ionized water, the step of mixing the powders with de-ionized water producing a slurry, sonifing the slurry to completely wet the powder and suspend the powder in the de-ionized water, separating very fine particles from the slurry, molding the slurry, and curing the slurry to produce the transparent ceramic.

Investigation of the Dependences of the Attenuation Properties of Cryogenic Metal-Powder Filters on the Preparation Method

NASA Astrophysics Data System (ADS)

Lee, Sung Hoon; Lee, Soon-Gul

2018-04-01

We fabricated low-pass metal powder filters for use in low-noise measurements at cryogenic temperatures and investigated their attenuation characteristics for different wire-turn densities, metalpowder shapes, and preparation methods at frequencies up to 20 GHz. We used nominally 30-μmsized stainless-steel 304L powder and mixed it with low-temperature binders. The low-temperature binders used were Stycast 2850FT (Emerson and Cumming) with catalyst 23LV and GE-7031 varnish. A 0.1-mm insulated copper wire was wound on preformed powder-mixture bobbins in the shape of a circular rod and was encapsulated in metal tubes with the powder mixture. All the fabricated powder filters showed a large attenuation at high frequencies with a cut-off frequency near 1 GHz. For filters of the same wire length, a lower wiring density showed a larger attenuation, which implies that the amount of powder in close contact with the wire determines the attenuation. Filters made of a powder/varnish mixture showed significantly larger attenuations than those of a powder/stycast mixture, and the attenuation improved with increasing powder ratio in the mixture. The low-temperature thermal conductivities of a 2 : 1 powder/Stycast mixture and a 5 : 1 powder/varnish mixture showed similar values at temperatures up to 4.2 K.

Room temperature structures and odd even behaviour of a homologous series of anhydrous lithium n-alkanoates

NASA Astrophysics Data System (ADS)

White, Nicole A. S.; Ellis, Henry A.

2008-10-01

The molecular structures of a homologous series of lithium n-alkanoates have been determined at room temperature using infrared spectroscopy, polarizing light microscopy and X-ray powder diffraction in conjunction with density and melting point measurements. For all the compounds investigated, asymmetric ionic metal-carboxylate coordination is proposed, with the molecules located within a triclinic crystal system with P1¯ space group. The molecules are nearly all of similar structure and are arranged within lamellar layers with four molecules per unit cell. The hydrocarbon chains, in nearly all trans conformation, are arranged tail-to-tail and tilted at an average angle of 55 ο to the planes containing lithium ions. The unit cell parameters such as sides: b and c increase linearly with increasing chain length whilst side a shows a linear decrease. Furthermore, the measured densities and melting points show odd-even behaviour, suggesting differences in molecular packing between odd and even chain length homologues. Geometric models are proposed to explain molecular orientation within a lamella and odd-even behaviour, involving the influence of terminal groups on the packing geometry of hydrocarbon chains within the lattice.

Scandinavian consumer preference for beef steaks packed with or without oxygen.

PubMed

Aaslyng, M D; Tørngren, M A; Madsen, N T

2010-07-01

Beef steaks retail-packed with (80% O(2), 20% CO(2)) or without oxygen (either skin-packed or gas-packed (69.6% N(2), 30% CO(2), 0.04% CO or 70% N(2), 30% CO(2))) were compared by consumers in Denmark (n=382), Norway (n=316) and Sweden (n=374). Two pairs of two steaks - one steak packed in a high oxygen atmosphere and one packed without oxygen - were given to the consumers. They were instructed to prepare the steaks at home on two consecutive days, and two persons had to taste each steak. In Denmark, the oxygen-free packing was either gas packing with CO (69.6% N(2), 30% CO(2), 0.04% CO) or without CO (70% N(2), 30% CO(2)), in Norway it was either gas packing with CO (69.6% N(2), 30% CO(2), 0.04% CO) or skin packing, and in Sweden it was either skin packing or gas packing without CO (70% N(2), 30% CO(2)). The meat represented animals that were between 17 and 80 months old (Denmark) and young bulls (Norway and Sweden). Consumers in all three countries clearly preferred steaks packed without oxygen, in terms of overall liking, willingness to pay and their preferred choice of one steak. Furthermore, they preferred the oxygen-free steaks in terms of both overall liking and liking of tenderness, juiciness and flavour. In Sweden, many consumers would pay more than usual for the skin-packed steak, and it was more often chosen as the preferred steak out of the four compared with gas-packed without oxygen. No difference was seen between the two oxygen-free packing methods in Denmark and Norway. Copyright 2010 Elsevier Ltd. All rights reserved.

Adsorption as a method of doping 3-mol%-yttria-stabilized zirconia powder with copper oxides

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

Seidensticker, J.R.; Mayo, M.J.; Osseo-Asare, K.

The adsorption behavior of Cu[sup 2+] on 3-mol%-yttria-stabilized tetragonal zirconia polycrystalline (3Y-TZP) powder was studied. There is a window of pH values (10 < pH < 11) where adsorption may be used as a method of doping 3Y-TZP with Cu[sup 2+]. The maximum mole percent of the CuO additions is determined by the specific surface area of the 3Y-TZP powder; a powder with a specific surface area of 16.1 m[sup 2]/g is limited to about 1 mol% CuO. Compacts made from powders doped with CuO using this method exhibited an enhancement in superplasticity comparable to that observed in other studiesmore » using samples doped with CuO by attrition milling.« less

Synthesis Of Nanosized CGYO Powders Via Glycine Nitrate Methods As Precursors For Dense Ceramic Membranes

NASA Astrophysics Data System (ADS)

Kochhar, Savinder P.; Singh, Anirudh P.

2011-12-01

Glycine nitrate combustion method was used to synthesize Ce0.8Gd0.1Y0.1O1.9 powders. Soluble metal-glycine complexes, detected by infrared spectroscopy, were formed by atomic level mixing of metal cations with glycine. The concentration of glycine has been varied in order to change the fuel to oxidant ratio i.e. of glycine to nitrate (g/n) with the purpose to study the effect of concentration of glycine on the parameters of resulting CGYO powder. The ratio of glycine to nitrate per mole is 0.5, 0.7, 0.8, 0.9, 1.0, 1.2, and 1.4. Increasing the glycine increases the temperatures reached during combustion. Powders prepared from GNP method demonstrated that combustion synthesized powders have large surface area as shown by SEM.

Preparation of tris(8-hydroxyquinolinato)aluminum thin films by sputtering deposition using powder and pressed powder targets

NASA Astrophysics Data System (ADS)

Kawasaki, Hiroharu; Ohshima, Tamiko; Yagyu, Yoshihito; Ihara, Takeshi; Tanaka, Rei; Suda, Yoshiaki

2017-06-01

Tris(8-hydroxyquinolinato)aluminum (Alq3) thin films, for use in organic electroluminescence displays, were prepared by a sputtering deposition method using powder and pressed powder targets. Experimental results suggest that Alq3 thin films can be prepared using powder and pressed powder targets, although the films were amorphous. The surface color of the target after deposition became dark brown, and the Fourier transform infrared spectroscopy spectrum changed when using a pressed powder target. The deposition rate of the film using a powder target was higher than that using a pressed powder target. That may be because the electron and ion densities of the plasma generated using the powder target are higher than those when using pressed powder targets under the same deposition conditions. The properties of a thin film prepared using a powder target were almost the same as those of a film prepared using a pressed powder target.

Groundwater well with reactive filter pack

DOEpatents

Gilmore, Tyler J.; Holdren, Jr., George R.; Kaplan, Daniel I.

1998-01-01

A method and apparatus for the remediation of contaminated soil and ground water wherein a reactive pack material is added to the annular fill material utilized in standard well construction techniques.

High Temperature Stable Nanocrystalline SiGe Thermoelectric Material

NASA Technical Reports Server (NTRS)

Yang, Sherwin (Inventor); Matejczyk, Daniel Edward (Inventor); Determan, William (Inventor)

2013-01-01

A method of forming a nanocomposite thermoelectric material having microstructural stability at temperatures greater than 1000 C. The method includes creating nanocrystalline powder by cryomilling. The method is particularly useful in forming SiGe alloy powder.

Composition driven monolayer to bilayer transformation in a surfactant intercalated Mg-Al layered double hydroxide.

PubMed

Naik, Vikrant V; Chalasani, Rajesh; Vasudevan, S

2011-03-15

The structure and organization of dodecyl sulfate (DDS) surfactant chains intercalated in an Mg-Al layered double hydroxide (LDH), Mg(1-x)Alx(OH)2, with differing Al/Mg ratios has been investigated. The Mg-Al LDHs can be prepared over a range of compositions with x varying from 0.167 to 0.37 and therefore provides a simple system to study how the organization of the alkyl chains of the intercalated DDS anions change with packing density; the Al/Mg ratio or x providing a convenient handle to do so. Powder X-ray diffraction measurements showed that at high packing densities (x ≥ 0.3) the alkyl chains of the intercalated dodecyl sulfate ions are anchored on opposing LDH sheets and arranged as bilayers with an interlayer spacing of ∼27 Å. At lower packing densities (x < 0.2) the surfactant chains form a monolayer with the alkyl chains oriented flat in the galleries with an interlayer spacing of ∼8 Å. For the in between compositions, 0.2 ≤ x < 0.3, the material is biphasic. MD simulations were performed to understand how the anchoring density of the intercalated surfactant chains in the Mg-Al LDH-DDS affects the organization of the chains and the interlayer spacing. The simulations are able to reproduce the composition driven monolayer to bilayer transformation in the arrangement of the intercalated surfactant chains and in addition provide insights into the factors that decide the arrangement of the surfactant chains in the two situations. In the bilayer arrangement, it is the dispersive van der Waals interactions between chains in opposing layers of the anchored bilayer that is responsible for the cohesive energy of the solid whereas at lower packing densities, where a monolayer arrangement is favored, Coulomb interactions between the positively charged Mg-Al LDH sheets and the negatively charged headgroup of the DDS anion dominate.

Evaluation of Rock Powdering Methods to Obtain Fine-grained Samples for CHEMIN, a Combined XRD/XRF Instrument

NASA Technical Reports Server (NTRS)

Chipera, S. J.; Vaniman, D. T.; Bish, D. L.; Sarrazin, P.; Feldman, S.; Blake, D. F.; Bearman, G.; Bar-Cohen, Y.

2004-01-01

A miniature XRD/XRF (X-ray diffraction / X-ray fluorescence) instrument, CHEMIN, is currently being developed for definitive mineralogic analysis of soils and rocks on Mars. One of the technical issues that must be addressed to enable remote XRD analysis is how best to obtain a representative sample powder for analysis. For powder XRD analyses, it is beneficial to have a fine-grained sample to reduce preferred orientation effects and to provide a statistically significant number of crystallites to the X-ray beam. Although a two-dimensional detector as used in the CHEMIN instrument will produce good results even with poorly prepared powder, the quality of the data will improve and the time required for data collection will be reduced if the sample is fine-grained and randomly oriented. A variety of methods have been proposed for XRD sample preparation. Chipera et al. presented grain size distributions and XRD results from powders generated with an Ultrasonic/Sonic Driller/Corer (USDC) currently being developed at JPL. The USDC was shown to be an effective instrument for sampling rock to produce powder suitable for XRD. In this paper, we compare powder prepared using the USDC with powder obtained with a miniaturized rock crusher developed at JPL and with powder obtained with a rotary tungsten carbide bit to powders obtained from a laboratory bench-scale Retsch mill (provides benchmark mineralogical data). These comparisons will allow assessment of the suitability of these methods for analysis by an XRD/XRF instrument such as CHEMIN.

Hashish Body Packing: A Case Report

PubMed Central

Soriano-Perez, Manuel Jesus; Serrano-Carrillo, Jose Luis; Marin-Montin, Inmaculada; Cruz-Caballero, Alfonso

2009-01-01

A 42-year-old African male was brought by the police to the emergency department under suspicion of drug smuggling by body-packing. Plain abdominal radiograph showed multiple foreign bodies within the gastrointestinal tract. Contrast-enhanced abdominal CT confirmed the findings, and the patient admitted to have swallowed “balls” of hashish. Body-packing is a recognized method of smuggling drugs across international borders. Body packers may present to the emergency department because of drug toxicity, intestinal obstruction, or more commonly, requested by law-enforcement officers for medical confirmation or exclusion of suspected body packing. PMID:19724651

Melamine detection in infant formula powder using near- and mid-infrared spectroscopy.

PubMed

Mauer, Lisa J; Chernyshova, Alona A; Hiatt, Ashley; Deering, Amanda; Davis, Reeta

2009-05-27

Near- and mid-infrared spectroscopy methods (NIR, FTIR-ATR, FTIR-DRIFT) were evaluated for the detection and quantification of melamine in infant formula powder. Partial least-squares (PLS) models were established for correlating spectral data to melamine concentration: R(2) > 0.99, RMSECV ≤ 0.9, and RPD ≥ 12. Factorization analysis of spectra was able to differentiate unadulterated infant formula powder from samples containing 1 ppm melamine with no misclassifications, a confidence level of 99.99%, and selectivity > 2. These nondestructive methods require little or no sample preparation. The NIR method has an assay time of 1 min, and a 2 min total time to detection. The FTIR methods require up to 5 min for melamine detection. Therefore, NIR and FTIR methods enable rapid detection of 1 ppm melamine in infant formula powder.

Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

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

Tanaka, Masahiko, E-mail: masahiko@spring8.or.jp; Katsuya, Yoshio, E-mail: katsuya@spring8.or.jp; Sakata, Osami, E-mail: SAKATA.Osami@nims.go.jp

2016-07-27

Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe{sub 2}O{sub 4} (inverse spinel structure) using X-rays near Fe K absorptionmore » edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe{sub 2}O{sub 4} crystal structure.« less

Titanium dental copings prepared by a powder metallurgy method: a preliminary report.

PubMed

Eriksson, Mikael; Andersson, Matts; Carlström, Elis

2004-01-01

The purpose of this study was to determine if the Procera pressed-powder method can be used to fabricate titanium copings. Commercially pure titanium powder was used to prepare the copings. The powder was pressed onto an enlarged tooth preparation die of aluminum using cold isostatic pressing. The outer shape of the coping was formed using a Procera milling machine, and the copings were vacuum sintered. Titanium copings could be prepared using this method. The density of the sintered copings reached 97% to 99%+ of theoretic density, and the copings showed ductile behavior after sintering. Enlarging the tooth preparation die to compensate for the sintering shrinkage could optimize the final size of the copings. Ductile and dense titanium dental copings can be produced with powder-metal processing using cold isostatic pressing, followed by milling and sintering to final shape. The forming technique has, if properly optimized, a potential of becoming a more cost-efficient production method than spark erosion.

Powder Metallurgy Reconditioning of Food and Processing Equipment Components

NASA Astrophysics Data System (ADS)

Nafikov, M. Z.; Aipov, R. S.; Konnov, A. Yu.

2017-12-01

A powder metallurgy method is developed to recondition the worn surfaces of food and processing equipment components. A combined additive is composed to minimize the powder losses in sintering. A technique is constructed to determine the powder consumption as a function of the required metallic coating thickness. A rapid method is developed to determine the porosity of the coating. The proposed technology is used to fabricate a wear-resistant defectless metallic coating with favorable residual stresses, and the adhesive strength of this coating is equal to the strength of the base metal.

An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

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

Wen, Haiming; Lin, Yaojun; Seidman, David N.

The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

An efficient and cost-effective method for preparing transmission electron microscopy samples from powders

DOE PAGES

Wen, Haiming; Lin, Yaojun; Seidman, David N.; ...

2015-09-09

The preparation of transmission electron microcopy (TEM) samples from powders with particle sizes larger than ~100 nm poses a challenge. The existing methods are complicated and expensive, or have a low probability of success. Herein, we report a modified methodology for preparation of TEM samples from powders, which is efficient, cost-effective, and easy to perform. This method involves mixing powders with an epoxy on a piece of weighing paper, curing the powder–epoxy mixture to form a bulk material, grinding the bulk to obtain a thin foil, punching TEM discs from the foil, dimpling the discs, and ion milling the dimpledmore » discs to electron transparency. Compared with the well established and robust grinding–dimpling–ion-milling method for TEM sample preparation for bulk materials, our modified approach for preparing TEM samples from powders only requires two additional simple steps. In this article, step-by-step procedures for our methodology are described in detail, and important strategies to ensure success are elucidated. Furthermore, our methodology has been applied successfully for preparing TEM samples with large thin areas and high quality for many different mechanically milled metallic powders.« less

Practical issues relating to soil column chromatography for sorption parameter determination.

PubMed

Bi, Erping; Schmidt, Torsten C; Haderlein, Stefan B

2010-08-01

Determination of sorption distribution coefficients (K(d)) of organic compounds by a dynamic soil column chromatography (SCC) method was developed and validated. Eurosoil 4, quartz, and alumina were chosen as exemplary packing materials. Heterocyclic aromatic compounds were selected in the validation of SCC. The prerequisites of SCC with regard to column dimension, packing procedure, and sample injection volume are discussed. Reproducible soil column packing was achieved by addition of a pre-column and an HPLC pump for subsequent compression of the packed material. Various methods to determine retention times from breakthrough curves are discussed and the use of the half mass method is recommended. To dilute soil with inert material can prevent column-clogging and help to complete experiments in a reasonable period of time. For the chosen probe compounds, quartz rather than alumina proved a suitable dilution material. Non-equilibrium issue can be overcome by conducting the experiments under different flowrates and/or performing numerical simulation. Copyright 2010 Elsevier Ltd. All rights reserved.

[Controlled release of prednisolone from suppository prepared using powder of pulverized tablet].

PubMed

Tatsumi, Akitoshi; Oda, Shoko; Nakamoto, Tomoko; Muraoka, Reiko; Takahashi, Yoshiko; Tanaka, Kuniyoshi; Shikata, Toshiyuki; Tatsumi, Sumiyo; Tagawa, Noriko; Kobayashi, Yoshiharu; Hamaguchi, Tsuneo; Kadobayashi, Muneo

2008-04-01

Prednisolone suppositories have been used successfully for the treatment of ulcerative colitis in hospital settings. However, the raw material of prednisolone suppository, JP prednisolone powder (JP Powder), was recently removed from the market. Therefore we studied the effects of raw material and suppository base on the release of prednisolone suppository for the purpose of designing a new suppository with similar effects to those of suppository prepared using JP powder (old suppository). New suppositories consisting of the powder of pulverized tablet as raw material and Witepsol H-15 and Witepsol E-75 as suppository base were prepared according to the fusion method. Suppository release test was performed by reciprocating dialysis tube method with tapping (RDT method) and dialysis tubing method (DT method). Both RDT method and DT method were performed using a suppository dissolution apparatus (modified JP disintegration apparatus) and a JP15 paddle apparatus, respectively. The test fluid was 50 mM phosphate buffer solution (pH 7.4) maintained at 37+/-0.5 degrees C. The results of release test by RDT method were similar to those of DT method. Release rate of prednisolone from the new suppository was much faster than that of old suppository. The addition of Witepsol E-75 to new suppository base markedly delayed the release of prednisolone from the new suppository. Release rate of prednisolone from the new suppository, consisting of pulverized tablet and Witepsol H-15 and Witepsol E-75 (76:24), corresponded well with that of the old suppository. It was suggested that this suppository could be used as incoming preparation of suppository prepared using JP powder.

Method of producing Pb-stabilized superconductor precursors and method of producing superconductor articles therefrom

DOEpatents

Kroeger, D.M.; Hsu, H.S.; Brynestad, J.

1995-03-07

Metal oxide superconductor powder precursors are prepared in an aerosol pyrolysis process. A solution of the metal cations is introduced into a furnace at 600--1,000 C for 0.1 to 60 seconds. The process produces micron to submicron size powders without the usual loss of the lead stabilizer. The resulting powders have a narrow particle size distribution, a small grain size, and are readily converted to a superconducting composition upon subsequent heat treatment. The precursors are placed in a metal body deformed to form a wire or tape and heated to form a superconducting article. The fine powders permit a substantial reduction in heat treatment time, thus enabling a continuous processing of the powders into superconducting wire, tape or multifilamentary articles by the powder-in-tube process. 3 figs.

Method of producing Pb-stabilized superconductor precursors and method of producing superconductor articles therefrom

DOEpatents

Kroeger, Donald M.; Hsu, Huey S.; Brynestad, Jorulf

1995-01-01

Metal oxide superconductor powder precursors are prepared in an aerosol pyrolysis process. A solution of the metal cations is introduced into a furnace at 600.degree.-1000.degree. C. for 0.1 to 60 seconds. The process produces micron to submicron size powders without the usual loss of the lead stabilizer. The resulting powders have a narrow particle size distribution, a small grain size, and are readily converted to a superconducting composition upon subsequent heat treatment. The precursors are placed in a metal body deformed to form a wire or tape and heated to form a superconducting article. The fine powders permit a substantial reduction in heat treatment time, thus enabling a continuous processing of the powders into superconducting wire, tape or multifilamentary articles by the powder-in-tube process.

Uniform-droplet spray forming

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

Blue, C.A.; Sikka, V.K.; Chun, Jung-Hoon

1997-04-01

The uniform-droplet process is a new method of liquid-metal atomization that results in single droplets that can be used to produce mono-size powders or sprayed-on to substrates to produce near-net shapes with tailored microstructure. The mono-sized powder-production capability of the uniform-droplet process also has the potential of permitting engineered powder blends to produce components of controlled porosity. Metal and alloy powders are commercially produced by at least three different methods: gas atomization, water atomization, and rotating disk. All three methods produce powders of a broad range in size with a very small yield of fine powders with single-sized droplets thatmore » can be used to produce mono-size powders or sprayed-on substrates to produce near-net shapes with tailored microstructures. The economical analysis has shown the process to have the potential of reducing capital cost by 50% and operating cost by 37.5% when applied to powder making. For the spray-forming process, a 25% savings is expected in both the capital and operating costs. The project is jointly carried out at Massachusetts Institute of Technology (MIT), Tuffs University, and Oak Ridge National Laboratory (ORNL). Preliminary interactions with both finished parts and powder producers have shown a strong interest in the uniform-droplet process. Systematic studies are being conducted to optimize the process parameters, understand the solidification of droplets and spray deposits, and develop a uniform-droplet-system (UDS) apparatus appropriate for processing engineering alloys.« less

Molecular structure, supramolecular organization and thermotropic phase behavior of N-acylglycine alkyl esters with matched acyl and alkyl chains.

PubMed

Reddy, S Thirupathi; Swamy, Musti J

2017-11-01

N-Acylglycines (NAGs), the endogenous single-tailed lipids present in rat brain and other mammalian tissues, play significant roles in cell physiology and exhibit interesting pharmacological properties. In the present study, a homologous series of N-acylglycine alkyl esters (NAGEs) with matched chains were synthesized and characterized. Results of differential scanning calorimetric studies revealed that all NAGEs exhibit a single sharp phase transition and that the transition enthalpy and entropy show a linear dependence on the N-acyl and ester alkyl chain length. The structure of N-myristoylglycine myristyl ester (NMGME), solved by single-crystal X-ray diffraction, showed that the molecule adopts a linear geometry and revealed that the structure of N-myristoyl glycyl moiety in NMGME is identical to that in N-myristoylglycine. The molecules are packed in layers with the polar functional groups of the ester and amide functionalities located at the center of the layer. The crystal packing is stabilized by NH⋯O hydrogen bonds between the amide CO and NH groups of adjacent molecules as well as by CH⋯O hydrogen bonds between the amide carbonyl and the methylene CH adjacent to the ester carbonyl of neighboring molecules as well as between ester carbonyl and methylene group of the glycine moiety of adjacent molecules. Powder X-ray diffraction studies showed a linear dependence of the d-spacings on the acyl chain length, suggesting that all NAGEs adopt a structure similar to the packing exhibited in the crystal lattice of NMGME. Copyright © 2017 Elsevier B.V. All rights reserved.

Method of making polymer powders and whiskers as well as particulate products of the method and atomizing apparatus

DOEpatents

Otaigbe, Joshua U.; McAvoy, Jon M.; Anderson, Iver E.; Ting, Jason; Mi, Jia; Terpstra, Robert

2001-01-09

Method for making polymer particulates, such as spherical powder and whiskers, by melting a polymer material under conditions to avoid thermal degradation of the polymer material, atomizing the melt using gas jet means in a manner to form atomized droplets, and cooling the droplets to form polymer particulates, which are collected for further processing. Atomization parameters can be controlled to produce polymer particulates with controlled particle shape, particle size, and particle size distribution. For example, atomization parameters can be controlled to produce spherical polymer powders, polymer whiskers, and combinations of spherical powders and whiskers. Atomizing apparatus also is provided for atoomizing polymer and metallic materials.

METHOD FOR SOLVENT-ISOSTATIC PRESSING

DOEpatents

Archibald, P.B.

1962-09-18

This invention provides a method for producing densely compacted bodies having relatively large dimensions. The method comprises the addition of a small quantity of a suitable solvent to a powder which is to be compacted. The solvent- moistened powder is placed inside a flexible bag, and the bag is suspended in an isostatic press. The solvent is squeezed out of the powder by the isostatic pressure, and the resulting compacted body is recovered. The presence of the solvent markedly decreases the proportion of void space in the powder, thereby resulting in a denser, more homogeneous compact. Another effect of the solvent is that it allows the isostatic pressing operation to be conducted at substantially lower pressures than are conventionally employed. (AEC)

Effect of drying environment on grain size of titanium dioxide nano-powder synthesized via sol-gel method

NASA Astrophysics Data System (ADS)

Zandi, Pegah; Hosseini, Elham; Rashchi, Fereshteh

2018-01-01

Titanium dioxide Nano powder has been synthesized from titanium isopropoxide (TTIP) in chloride media by sol-gel method. In this research, the effect of the drying environment, from air to oven drying at 100 °C, calcination time and temperature on nano TiO2 grain size was investigated. The synthesized powder was analyzed by x-ray diffraction and scanning electron microscope. Based on the results, the powder has been crystallized in anatase and rutile phases, due to different calcination temperatures. At temperatures above 600 °C, the Titanium dioxide nano powder has been crystallized as rutile. The crystalline structure of titanium dioxide nano powder changed because of the different calcination temperatures and time applied. The average particle size of the powder dried in air was larger than the powder dried in oven. The minimum particle size of the powder dried in air was 50 nm and in the oven was 9 nm, observed and calculated Williamson-Hall equation. All in all, with overall increasing of calcination time and temperature the grain size increased. Moreover, in the case of temperature, after a certain temperature, the grain size became constant and didn't change significantly.

[Use of powder metallurgy for development of implants of Co-Cr-Mo alloy powder].

PubMed

Dabrowski, J R

2001-04-01

This paper discusses the application of powder metallurgy for the development of porous implantation materials. Powders obtained from Co-Cr-Mo alloy with different carbon content by water spraying and grinding, have been investigated. Cold pressing and rotary re-pressing methods were used for compressing the powder. It was found that the sintered materials obtained from water spraying have the most advantageous properties.

Plasma methods of obtainment of multifunctional composite materials, dispersion-hardened by nanoparticles

NASA Astrophysics Data System (ADS)

Sizonenko, O. N.; Grigoryev, E. G.; Zaichenko, A. D.; Pristash, N. S.; Torpakov, A. S.; Lipyan, Ye V.; Tregub, V. A.; Zholnin, A. G.; Yudin, A. V.; Kovalenko, A. A.

2016-04-01

The new approach in developed plasma methods consists in that dispersionhardening additives (TiC, TiB2 in particular) are not mechanically added to powder mixture as additional component, as in conventional methods, but are instead synthesized during high voltage electric discharges (HVED) in disperse system “hydrocarbon liquid - powder” preservation of ultrafine structure is ensured due to use of spark plasma sintering (SPS) as a consolidation method. HVED in disperse system “hydrocarbon liquid - powder” due to impact of plasma discharge channel, electromagnetic fields, shock waves mechanical impact, hydro flows and volume microcavitation leads to synthesis of nanocarbon, metal powders dispersion and synthesis of micro- (from 10-6 to 10-7 m) and nanosized (from 10-7 to 10-9 m) composite powders of hardening phases. SPS is the passage of pulsed current (superposition of direct and alternating current) through powder with the simultaneous mechanical compressing. The formation of plasma is initiated in gaseous phase that fills gaps between particles. SPS allows targeted control of grain growth rate and thus allows obtainment of multifunctional composite materials dispersion hardened by nanoparticles. Processes of HVED synthesis of micro- and nanosized powders of new compositions from elemental metal powders and their mixtures with the subsequent application of high-speed SPS of obtained powders create conditions for increase of strength (by 10 - 20%), hardness and wear-resistance (by 30 - 60%) of obtained materials.

High-performance cation-exchange chromatofocusing of proteins.

PubMed

Kang, Xuezhen; Frey, Douglas D

2003-03-28

Chromatofocusing using high-performance cation-exchange column packings, as opposed to the more commonly used anion-exchange column packings, is investigated with regard to the performance achieved and the range of applications possible. Linear or convex gradients in the range from pH 2.6 to 9 were formed using a variety of commercially available column packings that provide a buffering capacity in different pH ranges, and either polyampholytes or simple mixtures having a small number (three or fewer) of buffering species as the elution buffer. The resolutions achieved using cation-exchange or anion-exchange chromatofocusing were in general comparable, although for certain pairs of proteins better resolution could be achieved using one type of packing as compared to the other, evidently due to the way electrostatic charges are distributed on the protein surface. Several chromatofocusing methods were investigated that take advantage of the acid-base properties of commercially available cation-exchange column packings. These include the use of gradients with a composite shape, the use of very low pH ranges, and the use of elution buffers containing a single buffering species. The advantages of chromatofocusing over ion-exchange chromatography using a salt gradient at constant pH were illustrated by employing the former method and a cation-exchange column packing to separate beta-lactoglobulins A and B, which is a separation reported to be impossible using the latter method and a cation-exchange column packing. Trends in the apparent isoelectric points determined using cation- and anion-exchange chromatofocusing were interpreted using applicable theories. Results of this study indicate that cation-exchange chromatofocusing is a useful technique which is complementary to anion-exchange chromatofocusing and isoelectric focusing for separating proteins at both the analytical and preparative scales.

Mesoporous metal oxide microsphere electrode compositions and their methods of making

DOEpatents

Paranthaman, Mariappan Parans; Liu, Hansan; Brown, Gilbert M.; Sun, Xiao-Guang; Bi, Zhonghe

2016-12-06

Compositions and methods of making are provided for mesoporous metal oxide microspheres electrodes. The mesoporous metal oxide microsphere compositions comprise (a) microspheres with an average diameter between 200 nanometers (nm) and 10 micrometers (.mu.m); (b) mesopores on the surface and interior of the microspheres, wherein the mesopores have an average diameter between 1 nm and 50 nm and the microspheres have a surface area between 50 m.sup.2/g and 500 m.sup.2/g. The methods of making comprise forming composite powders. The methods may also comprise refluxing the composite powders in a basic solution to form an etched powder, washing the etched powder with an acid to form a hydrated metal oxide, and heat-treating the hydrated metal oxide to form mesoporous metal oxide microspheres.

Secure hemostasis in transhiatal esophagectomy for esophageal cancer with gauze packing.

PubMed

Hirahara, Noriyuki; Matsubara, Takeshi; Hari, Yoko; Fujii, Yusuke; Wake, Hitomi; Tajima, Yoshitsugu

2012-12-19

Transhiatal esophagectomy for esophageal cancer implies blind manipulation of the intrathoracic esophagus. We report a secure hemostatic method with gauze packing in transhiatal esophagectomy. The gauze-packing technique is utilized for hemostasis just after removal of the thoracic esophagus during transhiatal esophagectomy. After confirming cancer-free margins, the abdominal esophagus and cervical esophagus are transected. A vein stripper is inserted into the oral-side stump of the esophagus and led to exit from the abdominal-side stump of the esophagus. The vein stripper and the oral stump of the esophagus are affixed by silk thread. A polyester tape is then affixed to the vein stripper, as the polyester tape is left in the posterior mediastinum after removal of the esophagus toward the abdominal side. The polyester tape on the cervical side is ligated with gauze and the polyester tape is removed toward the abdominal side. The oral stump of gauze and new additional gauze are affixed. As the first gauze is pulled out from the abdominal side, the second gauze gets drawn from the cervical wound into the mediastinum. The posterior mediastinum is finally packed with gauze and possible bleeding at this site undergoes a complete astriction. The status of hemostasis with the gauze packing is checked by an observation of color and bloodstain on the gauze. Between January 2005 and February 2012, 13 consecutive patients with esophageal cancer underwent a transhiatal esophagectomy with the gauze-packing hemostatic technique. Hemostasis at the posterior mediastinum was performed successfully and quickly in all cases with this method, requiring up to four pieces of gauze for a complete hemostasis. Median required time for hemostasis was 1219 (range 1896 to 1293) seconds and estimated blood loss was 20.4 (range 15 to 25) ml during gauze packing. Our technique could minimize bleeding after the removal of the thoracic esophagus. The gauze-packing method is a simple and easy technique for secure hemostasis when performing a transhiatal esophagectomy.

The effects of ethanol on the size-exclusion characteristics of type I dentin collagen to adhesive resin monomers.

PubMed

Chiba, A; Zhou, J; Nakajima, M; Tan, J; Tagami, J; Scheffel, D L S; Hebling, J; Agee, K A; Breschi, L; Grégoire, G; Jang, S S; Tay, F R; Pashley, D H

2016-03-01

During dentin bonding with etch-and-rinse adhesive systems, phosphoric acid etching of mineralized dentin solubilizes the mineral crystallites and replaces them with bound and unbound water. During the infiltration phase of dentin bonding, solvated adhesive resin comonomers are supposed to replace all of the unbound collagen water and polymerize into copolymers. A recently published review suggested that dental monomers are too large to enter and displace water from tightly-packed collagen molecules. Conversely, recent work from the authors' laboratory demonstrated that HEMA and TEGDMA freely equilibrate with water-saturated dentin matrices. However, because adhesive blends are solvated in organic solvents, those solvents may remove enough free water to allow collagen molecules to come close enough to exclude adhesive monomer permeation. The present study analyzed the size-exclusion characteristics of dentin collagen, using a gel permeation-like column chromatography technique, filled with dentin powder instead of Sephadex beads as the stationary phase. The elution volumes of different sized test molecules, including adhesive resin monomers, studied in both water-saturated dentin, and again in ethanol-dehydrated dentin powder, showed that adhesive resin monomers can freely diffuse into both hydrated and dehydrated collagen molecules. Under these in vitro conditions, all free and some of the loosely-bound water seems to have been removed by ethanol. These results validate the concept that adhesive resin monomers can permeate tightly-bound water in ethanol-saturated collagen molecules during infiltration by etch-and-rinse adhesives. It has been reported that collagen molecules in dentin matrices are packed too close together to allow permeation of adhesive monomers between them. Resin infiltration, in this view, would be limited to extrafibrillar spaces. Our work suggests that monomers equilibrate with collagen water in both water and ethanol-saturated dentin matrices. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Numerical simulation of a shear-thinning fluid through packed spheres

NASA Astrophysics Data System (ADS)

Liu, Hai Long; Moon, Jong Sin; Hwang, Wook Ryol

2012-12-01

Flow behaviors of a non-Newtonian fluid in spherical microstructures have been studied by a direct numerical simulation. A shear-thinning (power-law) fluid through both regular and randomly packed spheres has been numerically investigated in a representative unit cell with the tri-periodic boundary condition, employing a rigorous three-dimensional finite-element scheme combined with fictitious-domain mortar-element methods. The present scheme has been validated for the classical spherical packing problems with literatures. The flow mobility of regular packing structures, including simple cubic (SC), body-centered cubic (BCC), face-centered cubic (FCC), as well as randomly packed spheres, has been investigated quantitatively by considering the amount of shear-thinning, the pressure gradient and the porosity as parameters. Furthermore, the mechanism leading to the main flow path in a highly shear-thinning fluid through randomly packed spheres has been discussed.

Control of microparticles packing density in a microfluidic channel for bead based immunoassays applications

NASA Astrophysics Data System (ADS)

Caballero-Robledo, Gabriel; Guevara-Pantoja, Pablo

2014-11-01

Bead based immunoassays in microfluidic devices have shown to greatly outperform conventional methods. But if functional point-of-care devices are to be developed, precise and reproducible control over the granulate packings inside microchannels is needed. In this work we study the efficiency of a nanoparticles magnetic trap previously developed by B. Teste et al. [Lab Chip 11, 4207 (2011)] when we vary the compaction of micrometric iron beads packed against a restriction inside a microfluidic channel. The packing density of the beads is finely and reproducibly changed by applying a vibrational protocol originally developed for macroscopic, dry granular systems. We find, counterintuitively, that the most compact and stable packings are up to four times less efficient in trapping nano particles than the loosest packings. This work has been supported by Conacyt, Mexico, under Grant No. 180873.

An application of powder metallurgy to dentistry.

PubMed

Oda, Y; Ueno, S; Kudoh, Y

1995-11-01

Generally, the dental casting method is used to fabricate dental prostheses made with metal. The method of fabricating dental prostheses from sintered titanium alloy has certain advantages: the elimination of casting defects, a sintering temperature that is lower than the melting point, and a shorter processing time. By examining (1) the properties of green, sintered compacts of titanium powder, (2) the effects of adding aluminum powder on the properties of green, sintered compacts of Ti-Al compound, and (3) the effects of adding copper powder on the properties of green, sintered compacts of Ti-Al-Cu compound, the authors developed a sintered titanium alloy on a trial basis. Because the properties satisfied the requirements of dental restorations, a powder metallurgical method of making dental restorations from this sintered titanium alloy was devised. Applications of such sintered titanium alloys for the metal coping of metal-ceramic crowns and denture base plates were discussed.

Method for forming porous sintered bodies with controlled pore structure

DOEpatents

Whinnery, LeRoy Louis; Nichols, Monte Carl

2000-01-01

The present invention is based, in part, on a method for combining a mixture of hydroxide and hydride functional siloxanes to form a polysiloxane polymer foam, that leaves no residue (zero char yield) upon thermal decomposition, with ceramic and/or metal powders and appropriate catalysts to produce porous foam structures having compositions, densities, porosities and structures not previously attainable. The siloxanes are mixed with the ceramic and/or metal powder, wherein the powder has a particle size of about 400 .mu.m or less, a catalyst is added causing the siloxanes to foam and crosslink, thereby forming a polysiloxane polymer foam having the metal or ceramic powder dispersed therein. The polymer foam is heated to thermally decompose the polymer foam and sinter the powder particles together. Because the system is completely nonaqueous, this method further provides for incorporating reactive metals such as magnesium and aluminum, which can be further processed, into the foam structure.

Comparison of Nutrient Content and Cost of Home-Packed Lunches to Reimbursable School Lunch Nutrient Standards and Prices

ERIC Educational Resources Information Center

Johnson, Cara M.; Bednar, Carolyn; Kwon, Junehee; Gustof, Alissa

2009-01-01

Purpose: The purpose of this study was to compare nutrient content and cost of home-packed lunches to nutrient standards and prices for reimbursable school lunches. Methods: Researchers observed food and beverage contents of 333 home packed lunches at four north Texas elementary schools. Nutritionist Pro was used to analyze lunches for calories,…

Groundwater well with reactive filter pack

DOEpatents

Gilmore, T.J.; Holdren, G.R. Jr.; Kaplan, D.I.

1998-09-08

A method and apparatus are disclosed for the remediation of contaminated soil and ground water wherein a reactive pack material is added to the annular fill material utilized in standard well construction techniques. 3 figs.

Measure and dimension functions: measurability and densities

NASA Astrophysics Data System (ADS)

Mattila, Pertti; Mauldin, R. Daniel

1997-01-01

During the past several years, new types of geometric measure and dimension have been introduced; the packing measure and dimension, see [Su], [Tr] and [TT1]. These notions are playing an increasingly prevalent role in various aspects of dynamics and measure theory. Packing measure is a sort of dual of Hausdorff measure in that it is defined in terms of packings rather than coverings. However, in contrast to Hausdorff measure, the usual definition of packing measure requires two limiting procedures, first the construction of a premeasure and then a second standard limiting process to obtain the measure. This makes packing measure somewhat delicate to deal with. The question arises as to whether there is some simpler method for defining packing measure and dimension. In this paper, we find a basic limitation on this possibility. We do this by determining the descriptive set-theoretic complexity of the packing functions. Whereas the Hausdorff dimension function on the space of compact sets is Borel measurable, the packing dimension function is not. On the other hand, we show that the packing dimension functions are measurable with respect to the [sigma]-algebra generated by the analytic sets. Thus, the usual sorts of measurability properties used in connection with Hausdorff measure, for example measures of sections and projections, remain true for packing measure.

DEM simulation of dendritic grain random packing: application to metal alloy solidification

NASA Astrophysics Data System (ADS)

Olmedilla, Antonio; Založnik, Miha; Combeau, Hervé

2017-06-01

The random packing of equiaxed dendritic grains in metal-alloy solidification is numerically simulated and validated via an experimental model. This phenomenon is characterized by a driving force which is induced by the solid-liquid density difference. Thereby, the solid dendritic grains, nucleated in the melt, sediment and pack with a relatively low inertia-to-dissipation ratio, which is the so-called Stokes number. The characteristics of the particle packed porous structure such as solid packing fraction affect the final solidified product. A multi-sphere clumping Discrete Element Method (DEM) approach is employed to predict the solid packing fraction as function of the grain geometry under the solidification conditions. Five different monodisperse noncohesive frictionless particle collections are numerically packed by means of a vertical acceleration: a) three dendritic morphologies; b) spheres and c) one ellipsoidal geometry. In order to validate our numerical results with solidification conditions, the sedimentation and packing of two monodisperse collections (spherical and dendritic) is experimentally carried out in a viscous quiescent medium. The hydrodynamic similarity is respected between the actual phenomenon and the experimental model, that is a low Stokes number, o(10-3). In this way, the experimental average solid packing fraction is employed to validate the numerical model. Eventually, the average packing fraction is found to highly depend on the equiaxed dendritic grain sphericity, with looser packings for lower sphericity.

Effects of kinesio taping and hot packs on premenstrual syndrome in females.

PubMed

Choi, Jung-Hyun

2017-09-01

[Purpose] This study aimed to evaluate the effects of taping and hot packs on premenstrual syndrome, in an attempt to generate basic data for physical therapy intervention for premenstrual syndrome. [Subjects and Methods] Thirty-two females in their 20s with premenstrual syndrome were randomly assigned to a taping group (n=10), hot pack group (n=11), and taping with hot pack group (n=11). Premenstrual syndrome was assessed using the Menstrual Distress Questionnaire in each participant prior to intervention and was re-assessed after applying kinesio taping and/or hot pack from 10 days before the estimated date of menstruation until the first day of menstruation. [Results] Data revealed that the taping and taping with hot pack groups showed significantly reduced premenstrual syndrome following intervention. In terms of the differences in the Menstrual Distress Questionnaire total score among the groups, the taping with hot pack and hot pack groups showed a significant difference. [Conclusion] These findings indicate that kinesio taping is an easy, non-drug intervention for female college students with premenstrual syndrome.

Effects of kinesio taping and hot packs on premenstrual syndrome in females

PubMed Central

Choi, Jung-Hyun

2017-01-01

[Purpose] This study aimed to evaluate the effects of taping and hot packs on premenstrual syndrome, in an attempt to generate basic data for physical therapy intervention for premenstrual syndrome. [Subjects and Methods] Thirty-two females in their 20s with premenstrual syndrome were randomly assigned to a taping group (n=10), hot pack group (n=11), and taping with hot pack group (n=11). Premenstrual syndrome was assessed using the Menstrual Distress Questionnaire in each participant prior to intervention and was re-assessed after applying kinesio taping and/or hot pack from 10 days before the estimated date of menstruation until the first day of menstruation. [Results] Data revealed that the taping and taping with hot pack groups showed significantly reduced premenstrual syndrome following intervention. In terms of the differences in the Menstrual Distress Questionnaire total score among the groups, the taping with hot pack and hot pack groups showed a significant difference. [Conclusion] These findings indicate that kinesio taping is an easy, non-drug intervention for female college students with premenstrual syndrome. PMID:28931978

Capillary pressure-saturation relationships for porous granular materials: Pore morphology method vs. pore unit assembly method

NASA Astrophysics Data System (ADS)

Sweijen, Thomas; Aslannejad, Hamed; Hassanizadeh, S. Majid

2017-09-01

In studies of two-phase flow in complex porous media it is often desirable to have an estimation of the capillary pressure-saturation curve prior to measurements. Therefore, we compare in this research the capability of three pore-scale approaches in reproducing experimentally measured capillary pressure-saturation curves. To do so, we have generated 12 packings of spheres that are representative of four different glass-bead packings and eight different sand packings, for which we have found experimental data on the capillary pressure-saturation curve in the literature. In generating the packings, we matched the particle size distributions and porosity values of the granular materials. We have used three different pore-scale approaches for generating the capillary pressure-saturation curves of each packing: i) the Pore Unit Assembly (PUA) method in combination with the Mayer and Stowe-Princen (MS-P) approximation for estimating the entry pressures of pore throats, ii) the PUA method in combination with the hemisphere approximation, and iii) the Pore Morphology Method (PMM) in combination with the hemisphere approximation. The three approaches were also used to produce capillary pressure-saturation curves for the coating layer of paper, used in inkjet printing. Curves for such layers are extremely difficult to determine experimentally, due to their very small thickness and the presence of extremely small pores (less than one micrometer in size). Results indicate that the PMM and PUA-hemisphere method give similar capillary pressure-saturation curves, because both methods rely on a hemisphere to represent the air-water interface. The ability of the hemisphere approximation and the MS-P approximation to reproduce correct capillary pressure seems to depend on the type of particle size distribution, with the hemisphere approximation working well for narrowly distributed granular materials.

Method for removing oxide contamination from titanium diboride powder

DOEpatents

Brynestad, J.; Bamberger, C.E.

A method for removing oxide contamination from titanium diboride powder involves the direct chemical treatment of TiB/sub 2/ powders with a gaseous boron halide, such as BCl/sub 3/, at temperatures in the range of 500 to 800/sup 0/C. The BCl/sub 3/ reacts with the oxides to form volatile species which are removed by the BCl/sub 3/ exit stream.

Method for removing oxide contamination from titanium diboride powder

DOEpatents

Brynestad, Jorulf; Bamberger, Carlos E.

1984-01-01

A method for removing oxide contamination from titanium diboride powder involves the direct chemical treatment of TiB.sub.2 powders with a gaseous boron halide, such as BCl.sub.3, at temperatures in the range of 500.degree.-800.degree. C. The BCl.sub.3 reacts with the oxides to form volatile species which are removed by the BCl.sub.3 exit stream.

76 FR 29767 - Preventive Controls for Registered Human Food and Animal Food/Feed Facilities; Request for Comments

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-23

... associated with specific types of food or specific methods of manufacturing, processing, packing, or holding... specific methods of manufacturing, processing, packing, or holding food. In particular, we welcome input on... controls (e.g., procedures and practices utilized to minimize the risk of contamination) for human food and...

Method of filling a microchannel separation column

DOEpatents

Arnold, Don W.

2002-01-01

A method for packing a stationary phase into a small diameter fluid passageway or flow channel. Capillary action is employed to distribute a stationary phase uniformly along both the length and diameter of the flow channel. The method disclosed here: 1) eliminates the need for high pressure pumps and fittings and the safety hazards associated therewith; 2) allows the use of readily available commercial microparticles, either coated or uncoated, as the stationary phase; 3) provides for different types of particles, different particle sizes, and different particle size distributions to be packed in sequence, or simultaneously; 4) eliminates the need for plugging the flow channel prior to adding the stationary phase to retain the packing particles; and 5) many capillaries can be filled simultaneously.

Evaluation of thermal stress in hydroxyapatite film fabricated by powder jet deposition.

PubMed

Akatsuka, Ryo; Matsumura, Ken; Noji, Miyoko; Kuriyagawa, Tsunemoto; Sasaki, Keiichi

2013-10-01

This study aimed to create a thick hydroxyapatite (HA) film on the surface of a human tooth via a powder jet deposition (PJD) device for dental handpieces, and to examine the microstructural and mechanical properties of the HA film. In particular, the effects of thermal stress on this film were evaluated. The HA film was created by blasting 3.18-μm HA particles, calcinated at 1,200°C, onto the enamel substrate at room temperature and atmospheric pressure. An HA film with an area of 3 mm × 3 mm was prepared and polished. The following HA film parameters were evaluated from the three-dimensional surface profile: surface roughness, Vickers hardness, and bonding strength before and after artificial aging induced by 500 cycles of thermal cycling (5-55°C). The HA particles in the deposited film were densely packed, and the surface of the HA film was unchanged after thermal cycling. There were also no significant differences in the hardness and the bonding strength of the HA film before and after thermal cycling. The HA film created in this study demonstrated excellent microstructural and mechanical properties, even after the application of thermal stress. © 2013 Eur J Oral Sci.

Fatal heroin intoxication in body packers in northern Thailand during the last decade: two case reports.

PubMed

Sribanditmongkol, Pongruk; Supasingsiripreecha, Wiroon; Thampitak, Subharat; Junkuy, Anongphan

2006-01-01

A body packer is an important means of drug trafficking. While drug packets are inside the body, they can leak or rupture causing acute substance toxicity. Most of the reports of body packer syndrome have come from Europe and North America, which are destination targets. In the present study, the authors reported two cases of fatal heroin body packers from the northern part of Thailand. Both cases were foreign tourists who came to Chiang Mai and stayed in a hotel or a guesthouse room in which the deaths occurred. The autopsy findings revealed rupturing of heroin packages in the stomach. The packaging used in both cases was not sophisticated. The powder was packed inside condoms without extra covering, as observed in some other professional packers. The amount of heroin transported was about 30-50 gm. The purity of heroin in this powder was about 50-90%. Their destinations were their home countries and not directly to Europe or North America. Deaths occurred just prior to their return. The cause of death was a heroin overdose. A significant level of heroin metabolites, 6-MAM and morphine were detected in the blood and urine.

One-pot synthesis of powder-form β-Ni(OH)2 monolayer nanosheets with high electrochemical performance

NASA Astrophysics Data System (ADS)

Wang, Minmin; Ren, Wanzhong; Zhao, Yunan; Liu, Yan; Cui, Hongtao

2013-08-01

In this work, β-Ni(OH)2 monolayer nanosheets, which had been thought to be unachievable, were successfully prepared for the first time by a one-pot strategy using epoxide as precipitation agent and sodium dodecyl sulfate (SDS) as surfactant. The characterization results indicate that the formation of monolayer morphology depends on the mediation of SDS molecules. The XRD patterns demonstrate the loose and defective packing of Ni(OH)2 layers in the SDS intercalated samples. The disappearing of vibration band of free hydroxyl groups in the FTIR spectra suggests the interlayer separation resulted by SDS. The TEM and AFM images further confirm the formation of monolayer nanosheets. It is proposed that the in situ modification of the secondary growth unit of β-Ni(OH)2 by SDS allows its two-dimensional anisotropic growth through steric hindrance of SDS molecules. In addition, this effect allows isolation of β-Ni(OH)2 from solvent with keeping of monolayer nanosheet state in dry powder. The electrochemical measurement results indicate that β-Ni(OH)2 monolayer nanosheets own much higher urea electrolysis performance than their corresponding multilayer structure.

The structure and transformation of the nanomineral schwertmannite: a synthetic analog representative of field samples

NASA Astrophysics Data System (ADS)

French, Rebecca A.; Monsegue, Niven; Murayama, Mitsuhiro; Hochella, Michael F.

2014-04-01

The phase transformation of schwertmannite, an iron oxyhydroxide sulfate nanomineral synthesized at room temperature and at 75 °C using H2O2 to drive the precipitation of schwertmannite from ferrous sulfate (Regenspurg et al. in Geochim Cosmochim Acta 68:1185-1197, 2004), was studied using high-resolution transmission electron microscopy. The results of this study suggest that schwertmannite synthesized using this method should not be described as a single phase with a repeating unit cell, but as a polyphasic nanomineral with crystalline areas spanning less than a few nanometers in diameter, within a characteristic `pin-cushion'-like amorphous matrix. The difference in synthesis temperature affected the density of the needles on the schwertmannite surface. The needles on the higher-temperature schwertmannite displayed a dendritic morphology, whereas the needles on the room-temperature schwertmannite were more closely packed. Visible lattice fringes in the schwertmannite samples are consistent with the powder X-ray diffraction (XRD) pattern taken on the bulk schwertmannite and also matched d-spacings for goethite, indicating a close structural relationship between schwertmannite and goethite. The incomplete transformation from schwertmannite to goethite over 24 h at 75 °C was tracked using XRD and TEM. TEM images suggest that the sample collected after 24 h consists of aggregates of goethite nanocrystals. Comparing the synthetic schwertmannite in this study to a study on schwertmannite produced at 85 °C, which used ferric sulfate, reveals that synthesis conditions can result in significant differences in needle crystal structure. The bulk powder XRD patterns for the schwertmannite produced using these two samples were indistinguishable from one another. Future studies using synthetic schwertmannite should account for these differences when determining schwertmannite's structure, reactivity, and capacity to take up elements like arsenic. The schwertmannite synthesized by the Regenspurg et al. method produces a mineral that is consistent with the structure and morphology of natural schwertmannite observed in our previous study using XRD and TEM, making this an ideal synthetic method for laboratory-based mineralogical and geochemical studies that intend to be environmentally relevant.

The structure and mechanical properties of parts elaborated by direct laser deposition 316L stainless steel powder obtained in various ways

NASA Astrophysics Data System (ADS)

Loginova, I. S.; Solonin, A. N.; Prosviryakov, A. S.; Adisa, S. B.; Khalil, A. M.; Bykovskiy, D. P.; Petrovskiy, V. N.

2017-12-01

In this work the morphology, the size and the chemical composition of the powders of steel 316L received by the two methods was studied: fusion dispersion by a gas stream and reduction of metal chlorides with the subsequent plasma atomization of the received powder particles. The powder particles received by the first method have a spherical shape (aspect ratio 1,0-1,2) with an average size of 77 μm and are characterized by the absence of internal porosity. Particles of the powder received by the second method also have a spherical shape and faultless structure, however, their chemical composition may vary in different particles. The average size of particles is 32 μm. Though the obtained powders had different properties, the experimental samples received by DLD technology demonstrated by equally high durability (Ultimate strength is 623±5 and of 623±18 MPa respectively) and plasticity (38 and 41% respectively). It is established that mechanical properties of DLD samples increase for 7-10% after treatment of the surface.

Method for low temperature preparation of a noble metal alloy

DOEpatents

Even, Jr., William R.

2002-01-01

A method for producing fine, essentially contamination free, noble metal alloys is disclosed. The alloys comprise particles in a size range of 5 to 500 nm. The method comprises 1. A method for preparing a noble metal alloy at low temperature, the method comprising the steps of forming solution of organometallic compounds by dissolving the compounds into a quantity of a compatible solvent medium capable of solvating the organometallic, mixing a portion of each solution to provide a desired molarity ratio of ions in the mixed solution, adding a support material, rapidly quenching droplets of the mixed solution to initiate a solute-solvent phase separation as the solvent freezes, removing said liquid cryogen, collecting and freezing drying the frozen droplets to produce a dry powder, and finally reducing the powder to a metal by flowing dry hydrogen over the powder while warming the powder to a temperature of about 150.degree. C.

Nonharmonicity in vibrated granular solids

NASA Astrophysics Data System (ADS)

Schreck, Carl

2012-02-01

We have shown that granular packings composed of frictionless particles with repulsive contact interactions are strongly nonharmonic. When infinitesimally perturbed along linear response eigenmodes of the static packing, energy leaks from the original mode of vibration to a continuum of frequencies due solely to contact breaking even when the system is under significant compression. Further, vibrated packings possess well-defined equilibrium positions that are different than those of the unperturbed packing. The vibrational density of states obtained using the displacement matrix and velocity autocorrelation function methods exhibit an increase in the number of low-frequency modes over that obtained from linear response of the static packing. The form of the density of states in vibrated granular packings is reminiscent of the low-frequency behavior of the vibrational density of states in fluid systems. We also investigate the effects of inter-particle friction, dissipation, particle shape, and degree of positional order on the density of states and thermal transport properties in driven granular packings.

Two-stage energy storage equalization system for lithium-ion battery pack

NASA Astrophysics Data System (ADS)

Chen, W.; Yang, Z. X.; Dong, G. Q.; Li, Y. B.; He, Q. Y.

2017-11-01

How to raise the efficiency of energy storage and maximize storage capacity is a core problem in current energy storage management. For that, two-stage energy storage equalization system which contains two-stage equalization topology and control strategy based on a symmetric multi-winding transformer and DC-DC (direct current-direct current) converter is proposed with bidirectional active equalization theory, in order to realize the objectives of consistent lithium-ion battery packs voltages and cells voltages inside packs by using a method of the Range. Modeling analysis demonstrates that the voltage dispersion of lithium-ion battery packs and cells inside packs can be kept within 2 percent during charging and discharging. Equalization time was 0.5 ms, which shortened equalization time of 33.3 percent compared with DC-DC converter. Therefore, the proposed two-stage lithium-ion battery equalization system can achieve maximum storage capacity between lithium-ion battery packs and cells inside packs, meanwhile efficiency of energy storage is significantly improved.

Physical characteristics and aerosolization performance of insulin dry powders for inhalation prepared by a spray drying method.

PubMed

You, Yu; Zhao, Min; Liu, Guangli; Tang, Xing

2007-07-01

The objective of this study was to investigate the influence of formulation excipients on the physical characteristics and aerosolization performance of insulin dry powders for inhalation. Insulin dry powders were prepared by a spray drying technique using excipients such as sugars (trehalose, lactose and dextran), mannitol and amino acids (L-leucine, glycine and threonine). High performance liquid chromatography and the mouse blood glucose method were used for determination of the insulin content. The powder properties were determined and compared by scanning electron microscopy, thermo-gravimetric analysis and size distribution analysis by a time-of-flight technique. The in-vitro aerosolization behaviour of the powders was assessed with an Aerolizer inhaler using a twin-stage impinger. Powder yield and moisture absorption were also determined. Results showed that there was no noticeable change in insulin content in any of the formulations by both assay methods. All powders were highly wrinkled, with median aerodynamic diameters of 2-4 microm, and consequently suitable for pulmonary administration. The tapped density was reduced dramatically when glycine was added. The powders containing mannitol, with or without L-leucine, were less sensitive to moisture. The highest respirable fraction of 67.3 +/- 1.3% was obtained with the formulation containing L-leucine, in contrast to formulations containing glycine and threonine, which had a respirable fraction of 11.2 +/- 3.9% and 23.5 +/- 2.5%, respectively. In addition, powders with good physical properties were achieved by the combination of insulin and trehalose. This study suggests that L-leucine could be used to enhance the aerosolization behaviour of the insulin dry powders for inhalation, and trehalose could potentially be used as an excipient in the formulations.

Counterflow diffusion flame synthesis of ceramic oxide powders

DOEpatents

Katz, J.L.; Miquel, P.F.

1997-07-22

Ceramic oxide powders and methods for their preparation are revealed. Ceramic oxide powders are obtained using a flame process whereby one or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein the precursors are converted into ceramic oxide powders. The nature of the ceramic oxide powder produced is determined by process conditions. The morphology, particle size, and crystalline form of the ceramic oxide powders may be varied by the temperature of the flame, the precursor concentration ratio, the gas stream and the gas velocity. 24 figs.

Counterflow diffusion flame synthesis of ceramic oxide powders

DOEpatents

Katz, Joseph L.; Miquel, Philippe F.

1997-01-01

Ceramic oxide powders and methods for their preparation are revealed. Ceramic oxide powders are obtained using a flame process whereby one or more precursors of ceramic oxides are introduced into a counterflow diffusion flame burner wherein the precursors are converted into ceramic oxide powders. The nature of the ceramic oxide powder produced is determined by process conditions. The morphology, particle size, and crystalline form of the ceramic oxide powders may be varied by the temperature of the flame, the precursor concentration ratio, the gas stream and the gas velocity.

Comparative studies of industrial grade carbon black powders

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

Chawla, Komal, E-mail: komalchawla.rs@gmail.com; Chauhan, Alok P. S., E-mail: chauhan.alok@gmail.com, E-mail: alok.chauhan@alumni.stonybrook.edu

Comparative studies of two dissimilar industrial grade Carbon Black (CB) powders (N375 and N405) were conducted. The structure, surface area and particle size are the three important characteristics of CB powder that determine their processability and application as filler in preparing rubber compounds. The powders were characterized for their structure using dibutyl phthalate absorption (DBPA), particle size via laser particle size analyzer and surface area by nitrogen adsorption method. The structural characterization showed that N405 had lower DBPA in comparison to N375, confirming low structure of N405 grade CB powder. It was observed from the particle size analysis that N375more » was coarser than N405 grade CB. The total surface area values were determined by the BET method based on the cross sectional area of the nitrogen molecule. N375, a coarse grade CB powder with high structure, depicted less surface area as compared to N405.« less

Experiment Analysis and Modelling of Compaction Behaviour of Ag60Cu30Sn10 Mixed Metal Powders

NASA Astrophysics Data System (ADS)

Zhou, Mengcheng; Huang, Shangyu; Liu, Wei; Lei, Yu; Yan, Shiwei

2018-03-01

A novel process method combines powder compaction and sintering was employed to fabricate thin sheets of cadmium-free silver based filler metals, the compaction densification behaviour of Ag60Cu30Sn10 mixed metal powders was investigated experimentally. Based on the equivalent density method, the density-dependent Drucker-Prager Cap (DPC) model was introduced to model the powder compaction behaviour. Various experiment procedures were completed to determine the model parameters. The friction coefficients in lubricated and unlubricated die were experimentally determined. The determined material parameters were validated by experiments and numerical simulation of powder compaction process using a user subroutine (USDFLD) in ABAQUS/Standard. The good agreement between the simulated and experimental results indicates that the determined model parameters are able to describe the compaction behaviour of the multicomponent mixed metal powders, which can be further used for process optimization simulations.

Nasal packing and stenting

PubMed Central

Weber, Rainer K.

2011-01-01

Nasal packs are indispensable in ENT practice. This study reviews current indications, effectiveness and risks of nasal packs and stents. In endoscopic surgery, nasal packs should always have smooth surfaces to minimize mucosal damage, improve wound healing and increase patient comfort. Functional endoscopic endonasal sinus surgery allows the use of modern nasal packs, since pressure is no longer required. So called hemostatic/resorbable materials are a first step in this direction. However, they may lead to adhesions and foreign body reactions in mucosal membranes. Simple occlusion is an effective method for creating a moist milieu for improved wound healing and avoiding dryness. Stenting of the frontal sinus is recommended if surgery fails to produce a wide, physiologically shaped drainage path that is sufficiently covered by intact tissue. PMID:22073095

Prevention and suppression of metal packing fires.

PubMed

Roberts, Mark; Rogers, William J; Sam Mannan, M; Ostrowski, Scott W

2003-11-14

Structured packing has been widely used because of large surface area that makes possible columns with high capacity and efficiency. The large surface area also contributes to fire hazards because of hydrocarbon deposits that can easily combust and promote combustion of the thin metal packing materials. Materials of high surface area that can fuel fires include reactive metals, such as titanium, and materials that are not considered combustible, such as stainless steel. Column design and material selection for packing construction is discussed together with employee training and practices for safe column maintenance and operations. Presented also are methods and agents for suppression of metal fires. Guidance for prevention and suppression of metal fires is related to incidents involving packing fires in columns.

Method for molding ceramic powders

DOEpatents

Janney, Mark A.

1990-01-01

A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

Method for molding ceramic powders

DOEpatents

Janney, M.A.

1990-01-16

A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, where after the product may be sintered.

Radiological and practical aspects of body packing

PubMed Central

Reginelli, A; Pinto, F; Sica, G; Scaglione, M; Berger, F H; Romano, L; Brunese, L

2014-01-01

Body packing represents the concealment of illegal substances in a person's body with the aim of smuggling. “Body packers” either swallow drug-filled packets or introduce drug-filled packets into their bodies rectally or vaginally with the purpose of concealing them. The three main smuggled drugs are cocaine, heroin and cannabis products. Body packing represents a serious risk of acute narcotic toxicity from drug exposure, intestinal obstruction owing to pellet impaction and bowel perforation with consequent abdominal sepsis. A suspected body packer is generally admitted to hospital to perform imaging investigations and confirm the presence of drugs in his/her body. Radiological imaging methods are essential to diagnose body packing and to detect potential complications. Increasing sophistication of traffickers and improvements in packaging add to the detection difficulty. Radiologists should be aware of the appearance of drug packets in a range of imaging modalities. This article informs physicians about the challenging aspects of body packing, its background and medicolegal issues, what imaging methods can be used and what criteria are necessary to perform a correct diagnosis. PMID:24472727

Method for packing chromatographic beds

DOEpatents

Freeman, David H.; Angeles, Rosalie M.; Keller, Suzanne

1991-01-01

Column chromatography beds are packed through the application of static force. A slurry of the chromatography bed material and a non-viscous liquid is filled into the column plugged at one end, and allowed to settle. The column is transferred to a centrifuge, and centrifuged for a brief period of time to achieve a predetermined packing level, at a range generally of 100-5,000 gravities. Thereafter, the plug is removed, other fixtures may be secured, and the liquid is allowed to flow out through the bed. This results in an evenly packed bed, with no channeling or preferential flow characteristics.

The structural properties of barium cobalt hexaferrite powder prepared by a simple heat treatment method

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

Chauhan, Chetna, E-mail: chetna.chauhan@nirmauni.ac.in; Jotania, Rajshree, E-mail: rbjotania@gmail.com

2016-05-06

The W-type barium hexaferrite was prepared using a simple heat treatment method. The precursor was calcinated at 650°C for 3 hours and then slowly cooled to room temperature in order to obtain barium cobalt hexaferrite powder. The prepared powder was characterised by different experimental techniques like XRD, FTIR and SEM. The X-ray diffractogram of the sample shows W-and M phases. The particle size calculated by Debye Scherrer formula. The FTIR spectra of the sample was taken at room temperature by using KBr pallet method which confirms the formation of hexaferrite phase. The morphological study on the hexaferrite powder was carriedmore » out by SEM analysis.« less

Assessing Attentional Prioritization of Front-of-Pack Nutrition Labels using Change Detection

PubMed Central

Becker, Mark W.; Sundar, Raghav Prashant; Bello, Nora; Alzahabi, Reem; Weatherspoon, Lorraine; Bix, Laura

2015-01-01

We used a change detection method to evaluate attentional prioritization of nutrition information that appears in the traditional “Nutrition Facts Panel” and in front-of-pack nutrition labels. Results provide compelling evidence that front-of-pack labels attract attention more readily than the Nutrition Facts Panel, even when participants are not specifically tasked with searching for nutrition information. Further, color-coding the relative nutritional value of key nutrients within the front-of-pack label resulted in increased attentional prioritization of nutrition information, but coding using facial icons did not significantly increase attention to the label. Finally, the general pattern of attentional prioritization across front-of-pack designs was consistent across a diverse sample of participants. Our results indicate that color-coded, front-of-pack nutrition labels increase attention to the nutrition information of packaged food, a finding that has implications for current policy discussions regarding labeling change. PMID:26851468

Direct and simultaneous detection of organic and inorganic ingredients in herbal powder preparations by Fourier transform infrared microspectroscopic imaging

NASA Astrophysics Data System (ADS)

Chen, Jian-bo; Sun, Su-qin; Tang, Xu-dong; Zhang, Jing-zhao; Zhou, Qun

2016-08-01

Herbal powder preparation is a kind of widely-used herbal product in the form of powder mixture of herbal ingredients. Identification of herbal ingredients is the first and foremost step in assuring the quality, safety and efficacy of herbal powder preparations. In this research, Fourier transform infrared (FT-IR) microspectroscopic identification method is proposed for the direct and simultaneous recognition of multiple organic and inorganic ingredients in herbal powder preparations. First, the reference spectrum of characteristic particles of each herbal ingredient is assigned according to FT-IR results and other available information. Next, a statistical correlation threshold is determined as the lower limit of correlation coefficients between the reference spectrum and a larger number of calibration characteristic particles. After validation, the reference spectrum and correlation threshold can be used to identify herbal ingredient in mixture preparations. A herbal ingredient is supposed to be present if correlation coefficients between the reference spectrum and some sample particles are above the threshold. Using this method, all kinds of herbal materials in powder preparation Kouqiang Kuiyang San are identified successfully. This research shows the potential of FT-IR microspectroscopic identification method for the accurate and quick identification of ingredients in herbal powder preparations.

Evaluation of Turmeric Powder Adulterated with Metanil Yellow Using FT-Raman and FT-IR Spectroscopy

PubMed Central

Dhakal, Sagar; Chao, Kuanglin; Schmidt, Walter; Qin, Jianwei; Kim, Moon; Chan, Diane

2016-01-01

Turmeric powder (Curcuma longa L.) is valued both for its medicinal properties and for its popular culinary use, such as being a component in curry powder. Due to its high demand in international trade, turmeric powder has been subject to economically driven, hazardous chemical adulteration. This study utilized Fourier Transform-Raman (FT-Raman) and Fourier Transform-Infra Red (FT-IR) spectroscopy as separate but complementary methods for detecting metanil yellow adulteration of turmeric powder. Sample mixtures of turmeric powder and metanil yellow were prepared at concentrations of 30%, 25%, 20%, 15%, 10%, 5%, 1%, and 0.01% (w/w). FT-Raman and FT-IR spectra were acquired for these mixture samples as well as for pure samples of turmeric powder and metanil yellow. Spectral analysis showed that the FT-IR method in this study could detect the metanil yellow at the 5% concentration, while the FT-Raman method appeared to be more sensitive and could detect the metanil yellow at the 1% concentration. Relationships between metanil yellow spectral peak intensities and metanil yellow concentration were established using representative peaks at FT-Raman 1406 cm−1 and FT-IR 1140 cm−1 with correlation coefficients of 0.93 and 0.95, respectively. PMID:28231130

Critical current densities of powder-in-tube MgB2 tapes fabricated with nanometer-size Mg powder

NASA Astrophysics Data System (ADS)

Yamada, H.; Hirakawa, M.; Kumakura, H.; Matsumoto, A.; Kitaguchi, H.

2004-03-01

We fabricated powder-in-tube MgB2/Fe tapes using a powder mixture of nanometer-size Mg and commercial amorphous B and investigated the transport properties. High-purity nanometer-size Mg powder was fabricated by applying the thermal plasma method. 5-10 mol % SiC powder doping was tried to enhance the Jc properties. We found that the use of nanometer-size Mg powder was effective to increase the Jc values. The transport Jc values of the nondoped and 10 mol % SiC-doped tapes prepared with nanometer-size Mg powder reached 90 and 250 A/mm2 at 4.2 K and 10 T, respectively. These values were about five times higher than those of the tapes prepared with commercial Mg powder.

Synthesis of submicron CaZrO{sub 3} in combustion reactions

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

Khaliullin, Sh. M., E-mail: khaliullin@ihim.uran.ru; Zhuravlev, V. D.; Bamburov, V. G.

Submicron CaZrO{sub 3} powder is obtained in combustion reactions (solution combustion synthesis—SCS) with glycine. It is found that SCS reduces the sintering temperature of CaZrO{sub 3} powders. The dielectric properties of calcium zirconate ceramics are studied by the electrochemical impedance method. It is shown that a ceramics of powders obtained by the SCS method has high dielectric characteristics.

Self-Lubricating Coatings for Elevated Temperature Applications Using A High-Velocity-Particle-Consolidation (HVPC) Process

DTIC Science & Technology

2008-12-01

Deposition of copper by cold gas dynamic spraying : An investigation of dependence of microstructure and properties of the deposits on the...the deposition of metals, alloys , polymers, and composite powder -materials onto various substrates without significant heating of the spray powders or... Spray method is a relatively new coating method for deposition of metal, alloy , polymer, and/or composite powder material onto

Method for producing a compressed body of mix-powder for ceramic

NASA Technical Reports Server (NTRS)

Okawa, K.

1983-01-01

Under the invented method, a compressed body of mix powder for ceramic is produced by mixing and stirring several raw powder materials with mixing liquid such as water, and, in the process of sending the resulted viscous material pressurized at 5 kg/cm to 7 kg/cm, using 1.5 to 2 times the pressure to filter and dehydrate, adjusting the water content to 10 to 20%.

Effect of mixing method on the mixing degree during the preparation of triturations.

PubMed

Nakamura, Hitoshi; Yanagihara, Yoshitsugu; Sekiguchi, Hiroko; Komada, Fusao; Kawabata, Haruno; Ohtani, Michiteru; Saitoh, Yukiya; Kariya, Satoru; Suzuki, Hiroshi; Uchino, Katsuyoshi; Iga, Tatsuji

2004-03-01

By using lactose colored with erythrocin, we investigated the effects of mixing methods on mixing degree during the preparation of trituration with a mortar and pestle. The extent of powder dilution was set to 4 to 64 fold in the experiments. We compared the results obtained by using two methods: (1) one-step mixing of powders after addition of diluents and (2) gradual mixing of powders after addition of diluents. As diluents, we used crystallized lactose and powdered lactose for the preparation of trituration. In the preparation of 64-fold trituration, an excellent degree of mixing was obtained, with CV values of less than 6.08%, for both preparation methods and for the two kinds of diluents. The mixing of two kinds of powders whose distributions of particle sizes were similar resulted in much better degree of mixing, with CV values of less than 3.0%. However, the concentration of principal agents in 64-fold trituration was reduced by 20% due to the adsorption of dye to the apparatus. Under conditions in which a much higher dilution rate and/or much better degree of dilution was required, it must be necessary to dilute powders with considering their physicality and to determine the concentrations of principal agents after the mixing.

Corrosion Screening of EV31A Magnesium and Other Magnesium Alloys using Laboratory-Based Accelerated Corrosion and Electro-Chemical Methods

DTIC Science & Technology

2014-07-01

corrosion studies (16). A schematic of the SWAP process and example of the powder produced is included in figure 4. This alloy contains amounts of Al ...advanced powder -based alloy and ZAXE1711 (both from Japan) were produced using a Spinning Water Atomization Process (SWAP) to yield powder particles with...and ZAXE1711 Mg alloy powders and (b) morphology of coarse Mg alloy powder prepared by SWAP

Liquid coated melt-spun Nd-Fe-B powders for bonded magnets

NASA Astrophysics Data System (ADS)

Li, D.; Gaiffi, S.; Kirk, D.; Young, K.; Herchenroeder, J.; Berwald, T.

1999-04-01

The liquid coating (LC) has been employed to apply epoxy and lubricant over the surface of rapidly solidified Nd-Fe-B powder particles. The LC led to an improvement of physical and magnetic properties for the powders and magnets compared to the dry blending and the encapsulation methods. The LC powders have excellent flowability and can be used for bonded magnets requiring very close tolerances; further bonded magnets made using this powder posses higher strength.

Time-of-flight neutron powder diffraction study on the third row transition metal hexafluorides WF6, OsF6, and PtF6

NASA Astrophysics Data System (ADS)

Marx, R.; Seppelt, K.; Ibberson, R. M.

1996-05-01

A neutron diffraction study on the third-row transition metal hexafluorides MF6 (M≡W, Os, Pt) has been performed using the high resolution neutron powder diffractometer (HRPD) at the spallation source ISIS, England. The previously unknown structures of the low-temperature phases of OsF6 and PtF6 are reported. WF6, OsF6, and PtF6, which exhibit a (5dt2g)0, (5dt2g)2, and (5dt2g)4 electronic configuration, respectively, are found to be isostructural and crystallize in the UF6 structure, space group Pmnb, (No. 62). The geometry of the MF6 molecules is to good approximation octahedral for each compound, the mean M-F bond length increasing only slightly from 182.5 (W) to 185.0 (Pt). For WF6 deviations from ideal octahedral geometry are only marginally significant [181.8(2) to 183.2(2) pm] and may be interpreted on the basis of packing effects. Deviations for the d2 complex OsF6 are somewhat larger [181.5(2) to 184.4(3) pm] and may be assumed to be caused by packing effects essentially the same as for WF6, in addition to a first-order Jahn-Teller effect arising from the (5dt2g)2 electronic configuration. While eliminating the effects of packing by a comparison of individual M-F bond lengths for WF6 and OsF6, the OsF6 molecule shows to have D4h symmetry with two apical M-F bonds about 1.8 pm longer than the four equatorial bonds as a result of the Jahn-Teller distortion. Only small deviations from ideal octahedral geometry [184.4(3) to 185.8(3) pm] are found for the d4 complex PtF6. Within the series W to Pt a substantial shortening of the F...F van der Waals contact distances is observed. This shortening more than compensates for the increase in the M-F bond lengths and leads to unit cell volumes and cell parameters decreasing continuously from W to Pt. The variation of F...F contact distances and M-F bond lengths may be rationalized in terms of polarization of the F-ligands in the field of the highly charged nuclei of the central atoms which are only incompletely shielded by the 5d electrons.

Automating the packing heuristic design process with genetic programming.

PubMed

Burke, Edmund K; Hyde, Matthew R; Kendall, Graham; Woodward, John

2012-01-01

The literature shows that one-, two-, and three-dimensional bin packing and knapsack packing are difficult problems in operational research. Many techniques, including exact, heuristic, and metaheuristic approaches, have been investigated to solve these problems and it is often not clear which method to use when presented with a new instance. This paper presents an approach which is motivated by the goal of building computer systems which can design heuristic methods. The overall aim is to explore the possibilities for automating the heuristic design process. We present a genetic programming system to automatically generate a good quality heuristic for each instance. It is not necessary to change the methodology depending on the problem type (one-, two-, or three-dimensional knapsack and bin packing problems), and it therefore has a level of generality unmatched by other systems in the literature. We carry out an extensive suite of experiments and compare with the best human designed heuristics in the literature. Note that our heuristic design methodology uses the same parameters for all the experiments. The contribution of this paper is to present a more general packing methodology than those currently available, and to show that, by using this methodology, it is possible for a computer system to design heuristics which are competitive with the human designed heuristics from the literature. This represents the first packing algorithm in the literature able to claim human competitive results in such a wide variety of packing domains.

[Blending powdered antineoplastic medicine in disposable ointment container].

PubMed

Miyazaki, Yasunori; Uchino, Tomonobu; Kagawa, Yoshiyuki

2014-01-01

On dispensing powdered antineoplastic medicines, it is important to prevent cross-contamination and environmental exposure. Recently, we developed a method for blending powdered medicine in a disposable ointment container using a planetary centrifugal mixer. The disposable container prevents cross-contamination. In addition, environmental exposure associated with washing the apparatus does not arise because no blending blade is used. In this study, we aimed to confirm the uniformity of the mixture and weight loss of medicine in the blending procedure. We blended colored lactose powder with Leukerin(®) or Mablin(®) powders using the new method and the ordinary pestle and mortar method. Then, the blending state was monitored using image analysis. Blending variables, such as the blending ratio (1:9-9:1), container size (35-125 mL), and charging rate (20-50%) in the container were also investigated under the operational conditions of 500 rpm and 50 s. At a 20% charging rate in a 35 mL container, the blending precision of the mixtures was not influenced by the blending ratio, and was less than 6.08%, indicating homogeneity. With an increase in the charging rate, however, the blending precision decreased. The possible amount of both mixtures rose to about 17 g with a 20% charging rate in a 125 mL container. Furthermore, weight loss of medicines with this method was smaller than that with the pestle and mortar method, suggesting that this method is safer for pharmacists. In conclusion, we have established a precise and safe method for blending powdered medicines in pharmacies.

Close-Packed Silicon Microelectrodes for Scalable Spatially Oversampled Neural Recording

PubMed Central

Scholvin, Jörg; Kinney, Justin P.; Bernstein, Jacob G.; Moore-Kochlacs, Caroline; Kopell, Nancy; Fonstad, Clifton G.; Boyden, Edward S.

2015-01-01

Objective Neural recording electrodes are important tools for understanding neural codes and brain dynamics. Neural electrodes that are close-packed, such as in tetrodes, enable spatial oversampling of neural activity, which facilitates data analysis. Here we present the design and implementation of close-packed silicon microelectrodes, to enable spatially oversampled recording of neural activity in a scalable fashion. Methods Our probes are fabricated in a hybrid lithography process, resulting in a dense array of recording sites connected to submicron dimension wiring. Results We demonstrate an implementation of a probe comprising 1000 electrode pads, each 9 × 9 μm, at a pitch of 11 μm. We introduce design automation and packaging methods that allow us to readily create a large variety of different designs. Significance Finally, we perform neural recordings with such probes in the live mammalian brain that illustrate the spatial oversampling potential of closely packed electrode sites. PMID:26699649

Freestanding Aligned Multi-walled Carbon Nanotubes for Supercapacitor Devices

NASA Astrophysics Data System (ADS)

Moreira, João Vitor Silva; Corat, Evaldo José; May, Paul William; Cardoso, Lays Dias Ribeiro; Lelis, Pedro Almeida; Zanin, Hudson

2016-11-01

We report on the synthesis and electrochemical properties of multi-walled carbon nanotubes (MWCNTs) for supercapacitor devices. Freestanding vertically-aligned MWCNTs and MWCNT powder were grown concomitantly in a one-step chemical vapour deposition process. Samples were characterized by scanning and transmission electron microscopies and Fourier transform infrared and Raman spectroscopies. At similar film thicknesses and surface areas, the freestanding MWCNT electrodes showed higher electrochemical capacitance and gravimetric specific energy and power than the randomly-packed nanoparticle-based electrodes. This suggests that more ordered electrode film architectures facilitate faster electron and ion transport during the charge-discharge processes. Energy storage and supply or supercapacitor devices made from these materials could bridge the gap between rechargeable batteries and conventional high-power electrostatic capacitors.

Surface-catalyzed air oxidation reactions of hydrazines: Tubular reactor studies

NASA Technical Reports Server (NTRS)

Kilduff, Jan E.; Davis, Dennis D.; Koontz, Steven L.

1988-01-01

The surface-catalyzed air oxidation reactions of hydrazine, monomethylhydrazine, unsymmetrical dimethylhydrazine, symmetrical dimethylhydrazine, trimethylhydrazine and tetramethylhydrazine were investigated in a metal-powder packed turbular flow reactor at 55 plus or minus 3 C. Hydrazine was completely reacted on all surfaces studied. The major products of monomethylhydrazine (MMH) oxidation were methanol, methane and methyldiazene. The di-, tri- and tetra-methyl hydrazines were essentially unreactive under these conditions. The relative catalytic reactivities toward MMH are: Fe greater than Al2O3 greater than Ti greater than Zn greater than 316 SS greater than Cr greater than Ni greater than Al greater than 304L SS. A kinetic scheme and mechanism involving adsorption, oxidative dehydrogenation and reductive elimination reactions on a metal oxide surface are proposed.

Flowability of granular materials with industrial applications - An experimental approach

NASA Astrophysics Data System (ADS)

Torres-Serra, Joel; Romero, Enrique; Rodríguez-Ferran, Antonio; Caba, Joan; Arderiu, Xavier; Padullés, Josep-Manel; González, Juanjo

2017-06-01

Designing bulk material handling equipment requires a thorough understanding of the mechanical behaviour of powders and grains. Experimental characterization of granular materials is introduced focusing on flowability. A new prototype is presented which performs granular column collapse tests. The device consists of a channel whose design accounts for test inspection using visualization techniques and load measurements. A reservoir is attached where packing state of the granular material can be adjusted before run-off to simulate actual handling conditions by fluidisation and deaeration of the pile. Bulk materials on the market, with a wide range of particle sizes, can be tested with the prototype and the results used for classification in terms of flowability to improve industrial equipment selection processes.

Effects of chronic dietary lead in American kestrels (Falco sparverius)

USGS Publications Warehouse

Franson, J. Christian; Sileo, Louis; Pattee, Oliver H.; Moore, John F.

1983-01-01

American kestrels were fed a diet containing 0, 10, or 50 ppm lead (Pb) powder for at least 5 mo. Blood delta-aminolevulinic acid dehydratase (ALAD) activity in birds receiving 50 ppm Pb was as low as 20% of controls but no significant effects were noted in packed cell volume (PCV) or hemoglobin concentration (Hb). Mean liver Pb residues in birds fed 50 ppm Pb were 1.3 and 2.4 ppm (dry wt) for males and females, respectively. Liver Pb residues in birds fed 10 ppm Pb were not significantly greater than controls. There was no significant correlation between blood ALAD activity and blood Pb concentration, no consistent histopathological lesions were noted, and body and organ weights were not affected.

Novel micro-extraction by packed sorbent procedure for the liquid chromatographic analysis of antiepileptic drugs in human plasma and urine.

PubMed

Rani, Susheela; Malik, Ashok K; Singh, Baldev

2012-02-01

A method for the simultaneous determination of the antiepileptic drugs, phenobarbital (PHB), phenytoin (PTN), carbamazepine (CBZ), primidone (PRM) and oxcarbazepine (OXC) in human plasma and urine samples by using micro-extraction in a packed syringe as the sample preparation method connected with LC/UV (MEPS/LC/UV) is described. Micro-extraction in a packed syringe (MEPS) is a new miniaturized, solid-phase extraction technique that can be connected online to gas or liquid chromatography without any modifications. In MEPS approximately 1 mg of the solid packing material is inserted into a syringe (100-250 μL) as a plug. Sample preparation takes place on the packed bed. The bed can be coated to provide selective and suitable sampling conditions. The new method is very promising, easy to use, fully automated, inexpensive and quick. The standard curves were obtained within the concentration range 1-500 ng/mL in both plasma and urine samples. The results showed high correlation coefficients (R(2) >0.988) for all of the analytes within the calibration range. The extraction recovery was found to be between 88.56 and 99.38%. The limit of quantification was found to be between 0.132 and 1.956 ng/mL. The precision (RSD) values of quality control samples (QC) had a maximum deviation of 4.9%. A comparison of the detection limits with similar methods indicates high sensitivity of the present method. The method is applied for the analysis of these drugs in real urine and plasma samples of epileptic patients. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method and apparatus for producing co-current fluid contact

DOEpatents

Trutna, William R.

1997-01-01

An improved packing system and method are disclosed wherein a packing section includes a liquid distributor and a separator placed above the distributor so that gas rising through the liquid distributor contacts liquid in the distributor, forming a gas-liquid combination which rises in co-current flow to the separator. Liquid is collected in the separator, from which gas rises.

Method and apparatus for producing co-current fluid contact

DOEpatents

Trutna, W.R.

1997-12-09

An improved packing system and method are disclosed wherein a packing section includes a liquid distributor and a separator placed above the distributor so that gas rising through the liquid distributor contacts liquid in the distributor, forming a gas-liquid combination which rises in co-current flow to the separator. Liquid is collected in the separator, from which gas rises. 13 figs.

Pharmaceutical production of tableting granules in an ultra-small-scale high-shear granulator as a pre-formulation study.

PubMed

Ogawa, Tatsuya; Uchino, Tomohiro; Takahashi, Daisuke; Izumi, Tsuyoshi; Otsuka, Makoto

2012-11-01

In some of drug developments, the amount of bulk drug powder to use in early stages is limited and it is not easy to supply a sufficient drug amount for conventional preparation methods. Therefore, an ultra-small-scale high-shear granulator (less than 5 g) (USG) was developed and applied to small-scale granulation as a pre-formulation. The sample powder consisted of 66.5% lactose, 28.5% microcrystalline cellulose and 5.0% hydroxypropylcellulose. The granules were obtained to agitate 5 g of the sample powder with 1.0 mL of water at 300 rpm for 5 min after pre-powder mixing for 3 min by the USG and the manual hand (HM) methods. The granules were evaluated by the 10% and 90% accumulated particle size and the recoveries of the granules and the powder solid. Median particle size for the USG and the HM methods was 159.2 ± 2.3 and 270.9 ± 14.9 µm, respectively. The USG method had a narrower particle size distribution than those by the HM method. The recovery of the granules by USG was significantly larger than that by the HM method. Characteristics of all of the granules indicated that the USG method could produce higher quality granules within a shorter time than the HM methods.

Development of advanced test methods for the improvement of production standards for ceramic powders used in solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Ward, Brian

Solid oxide fuel cells (SOFCs) are energy conversion devices that use ceramic powders as a precursor material for their electrodes. Presently, powder manufacturers are encountering complications producing consistent precursor powders. Through various thermal, chemical and physical tests, such as DSC and XRD, a preliminary production standard will be developed.

Production of inhalation phage powders using spray freeze drying and spray drying techniques for treatment of respiratory infections

PubMed Central

Leung, Sharon S.Y.; Parumasivam, Thaigarajan; Gao, Fiona G.; Carrigy, Nicholas B.; Vehring, Reinhard; Finlay, Warren H.; Morales, Sandra; Britton, Warwick J; Kutter, Elizabeth; Chan, Hak-Kim

2016-01-01

Purpose The potential of aerosol phage therapy for treating lung infections has been demonstrated in animal models and clinical studies. This work compared the performance of two dry powder formation techniques, spray freeze drying (SFD) and spray drying (SD), in producing inhalable phage powders. Method A Pseudomonas podoviridae phage, PEV2, was incorporated into multi-component formulation systems consisting of trehalose, mannitol and L-leucine (F1 = 60:20:20 and F2 = 40:40:20). The phage titer loss after the SFD and SD processes and in vitro aerosol performance of the produced powders were assessed. Results A significant titer loss (~ 2 log) was noted for droplet generation using an ultrasonic nozzle employed in the SFD method, but the conventional two-fluid nozzle used in the SD method was less destructive for the phage (~0.75 log loss). The phage were more vulnerable during the evaporative drying process (~0.75 log further loss) compared with the freeze drying step, which caused negligible phage loss. In vitro aerosol performance showed that the SFD powders (~80% phage recovery) provided better phage protection than the SD powders (~20% phage recovery) during the aerosolization process. Despite this, higher total lung doses were obtained for the SD formulations (SD-F1 = 13.1 ± 1.7 × 104 pfu and SD-F2 = 11.0 ± 1.4 × 104 pfu) than from their counterpart SFD formulations (SFD-F1 = 8.3 ± 1.8 × 104 pfu and SFD-F2 = 2.1 ± 0.3 × 104 pfu). Conclusion Overall, the SD method caused less phage reduction during the powder formation process and the resulted powders achieved better aerosol performance for PEV2. PMID:26928668

Aneurysm permeability following coil embolization: packing density and coil distribution

PubMed Central

Chueh, Ju-Yu; Vedantham, Srinivasan; Wakhloo, Ajay K; Carniato, Sarena L; Puri, Ajit S; Bzura, Conrad; Coffin, Spencer; Bogdanov, Alexei A; Gounis, Matthew J

2015-01-01

Background Rates of durable aneurysm occlusion following coil embolization vary widely, and a better understanding of coil mass mechanics is desired. The goal of this study is to evaluate the impact of packing density and coil uniformity on aneurysm permeability. Methods Aneurysm models were coiled using either Guglielmi detachable coils or Target coils. The permeability was assessed by taking the ratio of microspheres passing through the coil mass to those in the working fluid. Aneurysms containing coil masses were sectioned for image analysis to determine surface area fraction and coil uniformity. Results All aneurysms were coiled to a packing density of at least 27%. Packing density, surface area fraction of the dome and neck, and uniformity of the dome were significantly correlated (p<0.05). Hence, multivariate principal components-based partial least squares regression models were used to predict permeability. Similar loading vectors were obtained for packing and uniformity measures. Coil mass permeability was modeled better with the inclusion of packing and uniformity measures of the dome (r2=0.73) than with packing density alone (r2=0.45). The analysis indicates the importance of including a uniformity measure for coil distribution in the dome along with packing measures. Conclusions A densely packed aneurysm with a high degree of coil mass uniformity will reduce permeability. PMID:25031179

Growth of 3-D flower/grass-like metal oxide nanoarchitectures based on catalyst-assisted oxidation method

NASA Astrophysics Data System (ADS)

Hu, Lijiao; Ju, Yang; Hosoi, Atsushi

2014-03-01

Cu2O grass-like and ZnO flower-like nanoarchitectures were fabricated directly on Cu powders and Zn powders using a novel thermal oxidation stress-induced (TOS) method based on catalyst assistance at a low temperature of 150°C under moderate humid atmosphere. The experiments of Al powder were also carried out based on TOS method. Overlapping migration (OLM) of Cu and Zn atoms and toothpaste squeezing migration (TSM) of Al atoms caused by different atom densities in metal oxide materials were studied.

Additive manufacturing method for SRF components of various geometries

DOEpatents

Rimmer, Robert; Frigola, Pedro E; Murokh, Alex Y

2015-05-05

An additive manufacturing method for forming nearly monolithic SRF niobium cavities and end group components of arbitrary shape with features such as optimized wall thickness and integral stiffeners, greatly reducing the cost and technical variability of conventional cavity construction. The additive manufacturing method for forming an SRF cavity, includes atomizing niobium to form a niobium powder, feeding the niobium powder into an electron beam melter under a vacuum, melting the niobium powder under a vacuum in the electron beam melter to form an SRF cavity; and polishing the inside surface of the SRF cavity.

High-performance liquid chromatographic determination of benzil in air as an indicator of emissions derived from polyester powder coatings.

PubMed

Pukkila, J; Kokotti, H; Peltonen, K

1989-10-06

A method to estimate occupational exposure to emissions from the curing of polyester powder paints was developed. The method is based on the monitoring only of a certain marker compound in workroom air in order to make the determinations easier. Benzil, reproducibly emitted from all the powders tested, was chosen as the indicator for curing (220 degrees C)-derived emissions. A method for the air sampling and high-performance liquid chromatographic benzil is described. Aspects of the use of marker compounds are discussed.

Ternary ceramic thermal spraying powder and method of manufacturing thermal sprayed coating using said powder

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

Vogli, Evelina; Sherman, Andrew J.; Glasgow, Curtis P.

The invention describes a method for producing ternary and binary ceramic powders and their thermal spraying capable of manufacturing thermal sprayed coatings with superior properties. Powder contain at least 30% by weight ternary ceramic, at least 20% by weight binary molybdenum borides, at least one of the binary borides of Cr, Fe, Ni, W and Co and a maximum of 10% by weight of nano and submicro-sized boron nitride. The primary crystal phase of the manufactured thermal sprayed coatings from these powders is a ternary ceramic, while the secondary phases are binary ceramics. The coatings have extremely high resistance againstmore » corrosion of molten metal, extremely thermal shock resistance and superior tribological properties at low and at high temperatures.« less

High Temperature Mechanical Behavior of Polycrystalline Alumina from Mixed Nanometer and Micrometer Powders

NASA Technical Reports Server (NTRS)

Goldsby, Jon C.

2001-01-01

Sintered aluminum oxide materials were formed using commercial methods from mechanically mixed powders of nano-and micrometer alumina. The powders were consolidated at 1500 and 1600 C with 3.2 and 7.2 ksi applied stress in argon. The conventional micrometer sized powders failed to consolidate. While 100 percent nanometer-sized alumina and its mixture with the micrometer powders achieved less than 99 percent density. Preliminary high temperature creep behavior indicates no super-plastic strains. However high strains (less than 0.65 percent) were generated in the nanometer powder, due to cracks and linked voids initiated by cavitation.

Low Temperature Metal Coating Method Final Report CRADA No. TSB-1155-95

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

Kang, Sang-Wook; Gabel, Howard

A new metal coating method, cidled KEM (kinetic energy metal.lization), demonstrated in the laboratory by lnovati, utilized fast-moving solid particIes entrained in a gas that are caused to fiow through a nozzIe to effect particle deposition on metal surfaces at room temperature conditions. This method (US Patent 5,795,626) was an attractive and viabIe alternative to the currentIy available high-temperature coating methods avaiIabIe. Since it differs significantly from existing metal coating technologies, a brief description of the method is incIuded here. The proposed method, KEM, achieves cohesive and adhesive metallurgical bonding through the high-speed coUision of powder with a substrate andmore » the subsequent discharge of electrical charge at the substrate. Such coating is effected by entraining metal powder in a gas and accelerating this mixture through a supersonic nozzle. The gas/powder is directed towards the substrate to be coated. Collisions occur, initiaIly between the powder and the substrate, and, as the first Iayer of the coating forms, between the powder and the coating. During these collisions the powder is rapidly deformed, causing the exposure of fresh (oxide free) active metal surface. When these’active surfaces contact one another, they agglomerate and form true metaIIurgicaI bonds. The resultant coating has Iow porosity and high adhesive and cohesive strength. The formation of metaIIurgicaI bonds is potentiated by the discharge of electrical energy. This electrical energy is the result of triboeIectric charging of the particIes during acceleration and transit to the nozzIe. An advantage of the method is that it does not raise the temperature of the powder being appLiedor that of the substrate. Consequently, materials sensitive to high temperature may be applied without changing Me properties of the materkd or substrate.« less

Relative Packing Groups in Template-Based Structure Prediction: Cooperative Effects of True Positive Constraints

PubMed Central

Day, Ryan; Qu, Xiaotao; Swanson, Rosemarie; Bohannan, Zach; Bliss, Robert

2011-01-01

Abstract Most current template-based structure prediction methods concentrate on finding the correct backbone conformation and then packing sidechains within that backbone. Our packing-based method derives distance constraints from conserved relative packing groups (RPGs). In our refinement approach, the RPGs provide a level of resolution that restrains global topology while allowing conformational sampling. In this study, we test our template-based structure prediction method using 51 prediction units from CASP7 experiments. RPG-based constraints are able to substantially improve approximately two-thirds of starting templates. Upon deeper investigation, we find that true positive spatial constraints, especially those non-local in sequence, derived from the RPGs were important to building nearer native models. Surprisingly, the fraction of incorrect or false positive constraints does not strongly influence the quality of the final candidate. This result indicates that our RPG-based true positive constraints sample the self-consistent, cooperative interactions of the native structure. The lack of such reinforcing cooperativity explains the weaker effect of false positive constraints. Generally, these findings are encouraging indications that RPGs will improve template-based structure prediction. PMID:21210729

Iron-phosphate ceramics for solidification of mixed low-level waste

DOEpatents

Aloy, Albert S.; Kovarskaya, Elena N.; Koltsova, Tatiana I.; Macheret, Yevgeny; Medvedev, Pavel G.; Todd, Terry

2000-01-01

A method of immobilizing mixed low-level waste is provided which uses low cost materials and has a relatively long hardening period. The method includes: forming a mixture of iron oxide powders having ratios, in mass %, of FeO:Fe.sub.2 O.sub.3 :Fe.sub.3 O.sub.4 equal to 25-40:40-10:35-50, or weighing a definite amount of magnetite powder. Metallurgical cinder can also be used as the source of iron oxides. A solution of the orthophosphoric acid, or a solution of the orthophosphoric acid and ferric oxide, is formed and a powder phase of low-level waste and the mixture of iron oxide powders or cinder (or magnetite powder) is also formed. The acid solution is mixed with the powder phase to form a slurry with the ratio of components (mass %) of waste:iron oxide powders or magnetite:acid solution=30-60:15-10:55-30. The slurry is blended to form a homogeneous mixture which is cured at room temperature to form the final product.

Particle Morphology Effects on Flow Characteristics of PS304 Plasma Spray Coating Feedstock Powder Blend

NASA Technical Reports Server (NTRS)

Stanford, Malcolm K.; DellaCorte, Christopher; Eylon, Daniel

2002-01-01

The effects of BaF2-CaF 2 particle morphology on PS304 feedstock powder flow ability have been investigated. BaF2-CaF2 eutectic powders were fabricated by comminution (angular) and by gas atomization (spherical). The fluoride powders were added incrementally to the other powder constituents of the PS304 feedstock: nichrome, chromia, and silver powders. A linear relationship between flow time and concentration of BaF2-CaF2 powder was found. Flow of the powder blend with spherical BaF2-CaF2 was better than the angular BaF2-CaF2. Flow ability of the powder blend with angular fluorides decreased linearly with increasing fluoride concentration. Flow of the powder blend with spherical fluorides was independent of fluoride concentration. Results suggest that for this material blend, particle morphology plays a significant role in powder blend flow behavior, offering potential methods to improve powder flow ability and enhance the commercial potential. These findings may have applicability to other difficult-to-flow powders such as cohesive ceramics.

Evaluation Of A Powder-Free DNA Extraction Method For Skeletal Remains.

PubMed

Harrel, Michelle; Mayes, Carrie; Gangitano, David; Hughes-Stamm, Sheree

2018-02-07

Bones are often recovered in forensic investigations, including missing persons and mass disasters. While traditional DNA extraction methods rely on grinding bone into powder prior to DNA purification, the TBone Ex buffer (DNA Chip Research Inc.) digests bone chips without powdering. In this study, six bones were extracted using the TBone Ex kit in conjunction with the PrepFiler ® BTA™ DNA extraction kit (Thermo Fisher Scientific) both manually and via an automated platform. Comparable amounts of DNA were recovered from a 50 mg bone chip using the TBone Ex kit and 50 mg of powdered bone with the PrepFiler ® BTA™ kit. However, automated DNA purification decreased DNA yield (p < 0.05). Nevertheless, short tandem repeat (STR) success was comparable across all methods tested. This study demonstrates that digestion of whole bone fragments is an efficient alternative to powdering bones for DNA extraction without compromising downstream STR profile quality. © 2018 American Academy of Forensic Sciences.

Effect of solution combusted TiO2 nanopowder within commercial BaTiO3 dielectric layer on the photoelectric properties for AC powder electroluminescence devices.

PubMed

Park, Sung; Choi, Gil Rak; Kim, Youn Cheol; Lee, Jae Chun; Lee, Ju Hyeon

2013-05-01

A unique synthesis method was developed, which is called solution combustion method (SCM). TiO2 nanopowder was synthesized by this method. This SCM TiO2 nanopowder (-35 nm) was added to the dielectric layer of AC powder electroluminescence (EL) device. The dielectric layer was made of commercial BaTiO3 powder (-1.2 microm) and binding polymer. 0, 5, 10 and 15 wt% of SCM TiO2 nanopowder was added to the dielectric layer during fabrication of AC powder EL device respectively. Dielectric constant of these four kinds of dielectric layers was measured. The brightness and current density of AC powder EL device were also measured. When 10 wt% of SCM TiO2 nanopowder was added, dielectric constant and brightness were increased by 30% and 101% respectively. Furthermore, the current density was decreased by 71%. This means that the brightness was double and the power consumption was one third.

Sol-gel synthesis and densification of aluminoborosilicate powders. Part 2: Densification

NASA Technical Reports Server (NTRS)

Bull, Jeffrey; Selvaduray, Guna; Leiser, Daniel

1992-01-01

Aluminoborosilicate (ABS) powders, high in alumina content, were synthesized by the sol-gel process utilizing four different methods of synthesis. The effect of these methods on the densification behavior of ABS powder compacts was studied. Five regions of shrinkage in the temperature range 25-1184 C were identified. In these regions, the greatest shrinkage occurred between the gel-to-glass transition temperature (T sub g approximately equal to 835 C) and the crystallization transformation temperature (T sub t approximately equal 900 C). The dominant mechanism of densification in this range was found to be viscous sintering. ABS powders were amorphous to x-rays up to T sub t at which a multiphasic structure crystallized. No 2Al2O3.B2O3 was found in these powders as predicted in the phase diagram. Above T sub t, densification was the result of competing mechanisms including grain growth and boria fluxed viscous sintering. Apparent activation energies for densification in each region varied according to the method of synthesis.

Magnetic properties of co-precipitated hexaferrite powders with Sm-Co substitutions optimized with the molten flux method

NASA Astrophysics Data System (ADS)

Serletis, C.; Litsardakis, G.; Pavlidou, E.; Efthimiadis, K. G.

2017-11-01

In this work, using the chemical coprecipitation method, Sr1-xSmxFe12-xCoxO19 (x = 0, 0.1, 0.2) hexaferrite powders were prepared. Major magnetization loops were recorded at room temperature in order to determine the correct calcination temperature for optimum hard magnetic properties. It is found that a small degree of substitution increases substantially the coercive field. Also, the use of the molten flux calcination method increases the remanent magnetization. SEM/EDXS and XRD measurements were performed at the calcined powders: the results show that a single hexaferrite phase is formed and that the substituted powders consist of an assembly of grains with a mean diameter of 40 nm. Measurements of minor magnetization loops and of the temperature and time dependence of the magnetization confirm that the powders consist of a non-oriented single domain magnetic particles assembly. The results indicate that Sm could be a viable replacement for La in the manufacturing of hexaferrites with a high-energy product.

ROY Revisited, Again: The Eighth Solved Structure

DOE PAGES

Tan, Melissa; Shtukenberg, Alexander G.; Zhu, Shengcai; ...

2018-01-01

X-ray powder diffraction and crystal structure prediction (CSP) algorithms were used in synergy to establish the crystal structure of the eighth polymorph of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY), form R05. R05 crystallizes in the monoclinic space group P2_1 with lattice parameters a = 11.479(4) Å, b = 11.030(1) Å, c = 10.840(6) Å, β = 118.23(1)°. This is both the first acentric ROY polymorph, and the first with Z' > 1. The torsion angles defined by the S-C-N-C atom sequence of each molecule in the asymmetric unit are -34.0° and 44.9°. These angles fall between those previously determined for the red and orangemore » forms of ROY. Hirshfeld surface analysis was employed to understand the crystal packing and intermolecular interactions in R05 and an updated energy stability ranking was determined using computational methods. Finally, although the application of CSP was critical to the structure solution of R05, energy stability rankings determined using a series of DFT vdW-inclusive models substantially deviate from experiment, indicating that ROY polymorphism continues to be a challenge for CSP.« less

Kinetic Investigation and Wear Properties of Fe2B Layers on AISI 12L14 Steel

NASA Astrophysics Data System (ADS)

Keddam, M.; Ortiz-Dominguez, M.; Elias-Espinosa, M.; Arenas-Flores, A.; Zuno-Silva, J.; Zamarripa-Zepeda, D.; Gomez-Vargas, O. A.

2018-03-01

In the current study, the powder-pack boriding was applied to the AISI 12L14 steel in the temperature range 1123 K to 1273 K for an exposure time between 2 and 8 hours. The produced boride layer was composed of Fe2B with a sawtooth morphology. A diffusion model based on the integral method was applied to investigate the growth kinetics of Fe2B layers. As a main result, the boron diffusion coefficients in Fe2B were estimated by considering the principle of mass balance at the (Fe2B/substrate) interface with an inclusion of boride incubation times. The value of activation energy for boron diffusion in AISI 12L14 steel was estimated as 165 kJ mol-1 and compared with other values of activation energy found in the literature. An experimental validation of the present model was made by using four different boriding conditions. Furthermore, the Rockwell-C adhesion test was employed to assess the cohesion of boride layers to the base metal. The scratch and pin-on-disc tests were also carried out to analyze the effect of boriding on wear behavior of AISI 12L14 steel.

ROY Revisited, Again: The Eighth Solved Structure

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

Tan, Melissa; Shtukenberg, Alexander G.; Zhu, Shengcai

X-ray powder diffraction and crystal structure prediction (CSP) algorithms were used in synergy to establish the crystal structure of the eighth polymorph of 5-methyl-2-[(2-nitrophenyl)amino]-3-thiophenecarbonitrile (ROY), form R05. R05 crystallizes in the monoclinic space group P2_1 with lattice parameters a = 11.479(4) Å, b = 11.030(1) Å, c = 10.840(6) Å, β = 118.23(1)°. This is both the first acentric ROY polymorph, and the first with Z' > 1. The torsion angles defined by the S-C-N-C atom sequence of each molecule in the asymmetric unit are -34.0° and 44.9°. These angles fall between those previously determined for the red and orangemore » forms of ROY. Hirshfeld surface analysis was employed to understand the crystal packing and intermolecular interactions in R05 and an updated energy stability ranking was determined using computational methods. Finally, although the application of CSP was critical to the structure solution of R05, energy stability rankings determined using a series of DFT vdW-inclusive models substantially deviate from experiment, indicating that ROY polymorphism continues to be a challenge for CSP.« less

Development of a Novel Melt Spinning-Based Processing Route for Oxide Dispersion-Strengthened Steels

NASA Astrophysics Data System (ADS)

Hong, Zuliang; Morrison, Alasdair P. C.; Zhang, Hongtao; Roberts, Steve G.; Grant, Patrick S.

2018-02-01

Melt spinning of an Fe-5Y and Fe-1Y-1Ti (wt pct) alloy produced a relatively uniform spatial distribution of Y and Ti in solid solution and ribbons with consistent yield (> 60 pct by weight), fast processing time (< 10 seconds), good scalability (up to > 100 g feedstock material), and repeatability. Heat treatment in the presence of Fe2O3 as an oxygen source (Rhines pack method) at 973 K validated the potential of forming < 20 nm Y-rich oxides in the Fe-5Y ribbons. Pulverized Fe-1Y-1Y ribbons were consolidated to bulk using the field-assisted sintering technique (FAST) incorporating nano-sized Fe3O4 powder as the oxygen source. After FAST at 1273 K, 50 MPa, and 30 minutes, a comparatively high number density of sub-micron Y and/or Ti-rich oxides were developed. Further formation of fine-scale oxides took place during post-FAST annealing, resulting in an approximate 20 pct increase in hardness at temperatures below 573 K, but with a reduced hardening effect above 673 K due to a small fraction of persistent porosity and mechanically weak prior ribbon boundaries that were decorated with Ti-rich oxides.

Piroxicam/2-hydroxypropyl-beta-cyclodextrin inclusion complex prepared by a new fluid-bed coating technique.

PubMed

Zhang, Xingwang; Wu, Danni; Lai, Jie; Lu, Yi; Yin, Zongning; Wu, Wei

2009-02-01

This work was aimed at investigating the feasibility of fluid-bed coating as a new method to prepare cyclodextrin inclusion complex. The inclusion complex of the model drug piroxicam (PIX) and 2-hydroxypropyl-beta-cyclodextrin (HPCD) in aqueous ethanol solution was sprayed and deposited onto the surface of the pellet substrate upon removal of the solvent. The coating process was fluent with high coating efficiency. Scanning electron microscopy revealed a coarse pellet surface, and a loosely packed coating structure. Significantly enhanced dissolution, over 90% at 5 min, was observed at stoichiometric PIX/HPCD molar ratio (1/1) and at a ratio with excessive HPCD (1/2). Differential scanning calorimetry and powder X-ray diffractometry confirmed absence of crystallinity of PIX at PIX/HPCD molar ratio of 1/1 and 1/2. Fourier transform-infrared spectrometry and Raman spectrometry revealed interaction between PIX and HPCD adding evidence on inclusion of PIX moieties into HPCD cavities. Solid-state (13)C NMR spectrometry indicated possible inclusion of PIX through the pyridine ring. It is concluded that fluid-bed coating has potential to be used as a new technique to prepare cyclodextrin inclusion complex.

Method for stabilizing low-level mixed wastes at room temperature

DOEpatents

Wagh, A.S.; Singh, D.

1997-07-08

A method to stabilize solid and liquid waste at room temperature is provided comprising combining solid waste with a starter oxide to obtain a powder, contacting the powder with an acid solution to create a slurry, said acid solution containing the liquid waste, shaping the now-mixed slurry into a predetermined form, and allowing the now-formed slurry to set. The invention also provides for a method to encapsulate and stabilize waste containing cesium comprising combining the waste with Zr(OH){sub 4} to create a solid-phase mixture, mixing phosphoric acid with the solid-phase mixture to create a slurry, subjecting the slurry to pressure; and allowing the now pressurized slurry to set. Lastly, the invention provides for a method to stabilize liquid waste, comprising supplying a powder containing magnesium, sodium and phosphate in predetermined proportions, mixing said powder with the liquid waste, such as tritium, and allowing the resulting slurry to set. 4 figs.

Method for stabilizing low-level mixed wastes at room temperature

DOEpatents

Wagh, Arun S.; Singh, Dileep

1997-01-01

A method to stabilize solid and liquid waste at room temperature is provided comprising combining solid waste with a starter oxide to obtain a powder, contacting the powder with an acid solution to create a slurry, said acid solution containing the liquid waste, shaping the now-mixed slurry into a predetermined form, and allowing the now-formed slurry to set. The invention also provides for a method to encapsulate and stabilize waste containing cesium comprising combining the waste with Zr(OH).sub.4 to create a solid-phase mixture, mixing phosphoric acid with the solid-phase mixture to create a slurry, subjecting the slurry to pressure; and allowing the now pressurized slurry to set. Lastly, the invention provides for a method to stabilize liquid waste, comprising supplying a powder containing magnesium, sodium and phosphate in predetermined proportions, mixing said powder with the liquid waste, such as tritium, and allowing the resulting slurry to set.

Method of forming a hardened surface on a substrate

DOEpatents

Branagan, Daniel J.

2010-08-31

The invention includes a method of producing a hard metallic material by forming a mixture containing at least 55% iron and at least one of B, C, Si and P. The mixture is formed into an alloy and cooled to form a metallic material having a hardness of greater than about 9.2 GPa. The invention includes a method of forming a wire by combining a metal strip and a powder. The metal strip and the powder are rolled to form a wire containing at least 55% iron and from two to seven additional elements including at least one of C, Si and B. The invention also includes a method of forming a hardened surface on a substrate by processing a solid mass to form a powder, applying the powder to a surface to form a layer containing metallic glass, and converting the glass to a crystalline material having a nanocrystalline grain size.

Green synthesis of nanocrystalline α-Al2O3 powders by both wet-chemical and mechanochemical methods

NASA Astrophysics Data System (ADS)

Gao, Huiying; Li, Zhiyong; Zhao, Peng

2018-03-01

Nanosized α-Al2O3 powders were prepared with AlCl3ṡ6H2O and NH4HCO3 as raw materials by both wet-chemical and mechanochemical methods, through the synthesis of the ammonium aluminum carbonate hydroxide (AACH) precursor followed by calcination. The environmentally benign starch was used as an effective dispersant during the preparation of nanocrystalline α-Al2O3 powders. X-ray diffraction (XRD), thermogravimetric differential thermal analysis (TG-DTA), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were employed to characterize the precursor AACH and products. The results show that nanosized spherical α-Al2O3 powders without hard agglomeration and with particle size in the range of 20-40 nm can be obtained by the two methods. Comparing the two “green” processes, the mechanochemical method has better prospects for commercial production.

Method to estimate drag coefficient at the air/ice interface over drifting open pack ice from remotely sensed data

NASA Technical Reports Server (NTRS)

Feldman, U.

1984-01-01

A knowledge in near real time, of the surface drag coefficient for drifting pack ice is vital for predicting its motions. And since this is not routinely available from measurements it must be replaced by estimates. Hence, a method for estimating this variable, as well as the drag coefficient at the water/ice interface and the ice thickness, for drifting open pack ice was developed. These estimates were derived from three-day sequences of LANDSAT-1 MSS images and surface weather charts and from the observed minima and maxima of these variables. The method was tested with four data sets in the southeastern Beaufort sea. Acceptable results were obtained for three data sets. Routine application of the method depends on the availability of data from an all-weather air or spaceborne remote sensing system, producing images with high geometric fidelity and high resolution.

Flow, packing and compaction properties of novel coprocessed multifunctional directly compressible excipients prepared from tapioca starch and mannitol.

PubMed

Adeoye, Oluwatomide; Alebiowu, Gbenga

2014-12-01

Novel multifunctional excipients were prepared by coprocessing tapioca starch with mannitol using two methods viz; co-grinding and co-fusion. The flow, packing and compaction properties of the native and novel excipients were evaluated by using density, Hausner's ratio, angle of repose, the maximum volume reduction, consolidation index, the rate of consolidation, angle of internal friction, morphological properties, Heckel analysis, tensile strength and dilution potential as evaluation parameters. The study revealed that the method of coprocessing, particle size and particle shape influenced the properties of the resulting novel excipients. Co-grinding was less effective than co-fusion in the preparation of excipients with enhanced properties. The study concluded that coprocessing tapioca starch and mannitol will enhance the flow, packing and compaction properties of the novel excipient and that the co-fusion method of coprocessing would produce novel excipients with enhanced direct compression potential compared to the co-grinding method.

Study of Shell-Mold Thermal Resistance: Laboratory Measurements, Estimation from Compact Strip Production Plant Data, and Observation of Simulated Flux-Mold Interface

NASA Astrophysics Data System (ADS)

González de la C., J. Manuel; Flores F., Tania M.; Castillejos E., A. Humberto

2016-08-01

The slag film that forms between the shell and mold in steel continuous casting is key in regulating the heat transfer between them. Generally, the mechanisms proposed are related to the phenomena associated with the formation of crystals in the solid layer of the film, such as the appearance of internal pores and surface roughness, which decrease phononic conduction through the layer and interfacial gap with the mold, respectively, and the emergence of crystals themselves, which reduce the transmissivity of infrared radiation across the layer. Due to the importance of the solid layer, this study investigates experimentally the effective thermal resistance, R T, between a hot Inconel surface and a cold Cu surface separated by an initially glassy slag disk, made from powders for casting low and medium-carbon steels, denoted as A and B, respectively. In the tests, an initially mirror-polished disk is sandwiched for 10,800 seconds while the Inconel temperature, away from the disk face, is maintained steady at a value, T c, between 973 K and 1423 K (700 °C and 1150 °C)-below the liquidus temperature of the slags. The disks have a thickness, d t, between ~0.7 and 3.2 mm. Over the range of conditions studied, mold slag B shows R T 33 pct larger than slag A, and microscopic observation of disks hints that the greater resistance arises from the larger porosity developed in B. This finding is supported by high-temperature confocal laser scanning microscope observations of the evolution of the surface of slag parallelepipeds encased between Pt sheets, which reveal that during devitrification the film surface moves outward not inward, contrary with what is widely claimed. This behavior would favor contact of the slag with the mold for both kinds of powders. However, in the case of slag A, the crystalline grains growing at or near the surface pack closely together, leaving only few and small empty spaces. In slag B, crystalline grains pack loosely and many and large empty spaces arise in and below the surface. Estimation from plant data shows R T values smaller than measured ones, suggesting that the process film slag thickness must be considerably thinner than those of laboratory disks. However, the difference in thermal resistance of both powders, averaged over the mold length, is close to the dissimilarity found in laboratory.

[A technological study on the extraction of ultra-fine powder of Panax notoginsen].

PubMed

Huang, Yaohai; Huang, Mingqing; Zeng, Huifang; Guo, Wei; Xi, Ping

2005-12-01

To investigate the extraction of ultra-fine powder Panax notoginsen. The extraction rate of ginseng saponin Rg1, Re, Rb1, notoginseng saponin R1 and filtrated time were determined by alcoholic and aqueous extraction of Panax notoginsen in tablet, coarse powder, ultra-fine powder and recostitution granules of ultra-fine powder. The filtered time of ultra-fine powder of Panax notoginsen extraction and that of the tablet of Panax notoginsen extraction were similar, while the extraction rates of various saponins of it were high. The method of aqueous extrction in ltra-fine powder of Panax notoginsen is easy in filtrationer, higher in extraction rate of Panax notoginsen and lower in production cost.

ECG Changes in Young Healthy Smokers: A Simple and Cost-Effective Method to Assess Cardiovascular Risk According to Pack-Years of Smoking.

PubMed

Sharma, Nirmal Kumar; Jaiswal, Kapil Kumar; Meena, S R; Chandel, Rahul; Chittora, Saurabh; Goga, Prem Singh; Harish, H B; Sagar, Rajesh

2017-06-01

To document the prevalence of ECG abnormalities in young healthy smokers and compare ECG changes in smokers, young healthy non-smokers and amongst smokers with different pack years. This was a prospective case-control study consisting of 200 young healthy male and female individuals, 150 smokers and 50 non-smokers between ages 25-40 years, further categorized and compared according to age, sex and pack years of smoking. The ECG recordings were analyzed for different ECG parameters like heart rate, P-wave duration, P-wave amplitude, PR interval, QRS duration, RR-interval, ST-segment duration, QT interval and QTc interval. The results were compared using statistical tools. In present study abnormalities in ECG parameters were significantly more prevalent in smokers as compared to non-smokers (56.66 % Vs 6.00 %) (p <.0001). Heart rate and QTc-interval increased with increase in the number of pack-years. This increase was reflected more in female with a similar number of pack years. P-wave amplitude tended to increase with increase in the number of pack years more so in males. P-wave duration, PR-interval, QRS-duration and RR-interval tended to decrease with increase in the number of pack years more so in females with similar number of pack years. QT-interval and ST-segment duration tended to decrease with increase in the number of pack years more so in males. ECG abnormalities in this study indicate cardiovascular risk in term of cardiac arrhythmia, pulmonary arterial hypertension, heart blocks etc in such subjects. As this procedure is non-invasive and cost effective it is potentially an effective and yet a simple method for cardiovascular risk evaluation in smokers. Furthermore, such ECG abnormalities may guide the clinician for risk evaluation in smokers and may be used to convince the smokers to quit smoking.

Method for measuring recovery of catalytic elements from fuel cells

DOEpatents

Shore, Lawrence [Edison, NJ; Matlin, Ramail [Berkeley, NJ

2011-03-08

A method is provided for measuring the concentration of a catalytic clement in a fuel cell powder. The method includes depositing on a porous substrate at least one layer of a powder mixture comprising the fuel cell powder and an internal standard material, ablating a sample of the powder mixture using a laser, and vaporizing the sample using an inductively coupled plasma. A normalized concentration of catalytic element in the sample is determined by quantifying the intensity of a first signal correlated to the amount of catalytic element in the sample, quantifying the intensity of a second signal correlated to the amount of internal standard material in the sample, and using a ratio of the first signal intensity to the second signal intensity to cancel out the effects of sample size.

Solid state characterization and crystal structure from X-ray powder diffraction of two polymorphic forms of ranitidine base.

PubMed

de Armas, Héctor Novoa; Peeters, Oswald M; Blaton, Norbert; Van Gyseghem, Elke; Martens, Johan; Van Haele, Gerrit; Van Den Mooter, Guy

2009-01-01

Ranitidine hydrochloride (RAN-HCl), a known anti-ulcer drug, is the product of reaction between HCl and ranitidine base (RAN-B). RAN-HCl has been extensively studied; however this is not the case of the RAN-B. The solid state characterization of RAN-B polymorphs has been carried out using different analytical techniques (microscopy, thermal analysis, Fourier transform infrared spectrometry in the attenuated total reflection mode, (13)C-CPMAS-NMR spectroscopy and X-ray powder diffraction). The crystal structures of RAN-B form I and form II have been determined using conventional X-ray powder diffraction in combination with simulated annealing and whole profile pattern matching, and refined using rigid-body Rietveld refinement. RAN-B form I is a monoclinic polymorph with cell parameters: a = 7.317(2), b = 9.021(2), c = 25.098(6) A, beta = 95.690(1) degrees and space group P2(1)/c. The form II is orthorhombic: a = 31.252(4), b = 13.052(2), c = 8.0892(11) A with space group Pbca. In RAN-B polymorphs, the nitro group is involved in a strong intramolecular hydrogen bond responsible for the existence of a Z configuration in the enamine portion of the molecules. A tail to tail packing motif can be denoted via intermolecular hydrogen bonds. The crystal structures of RAN-B forms are compared to those of RAN-HCl polymorphs. RAN-B polymorphs are monotropic polymorphic pairs. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

Processing of laser formed SiC powder

NASA Technical Reports Server (NTRS)

Haggerty, J. S.; Bowen, H. K.

1985-01-01

Superior SiC characteristics can be achieved through the use of ideal constituent powders and careful post-synthesis processing steps. High purity SiC powders of approx. 1000 A uniform diameter, nonagglomerated and spherical were produced. This required major revision of the particle formation and growth model from one based on classical nucleation and growth to one based on collision and coalescence of Si particles followed by their carburization. Dispersions based on pure organic solvents as well as steric stabilization were investigated. Although stable dispersions were formed by both, subsequent part fabrication emphasized the pure solvents since fewer problems with drying and residuals of the high purity particles were anticipated. Test parts were made by the colloidal pressing technique; both liquid filtration and consolidation (rearrangement) stages were modeled. Green densities corresponding to a random close packed structure (approx. 63%) were achieved; this highly perfect structure has a high, uniform coordination number (greater than 11) approaching the quality of an ordered structure without introducing domain boundary effects. After drying, parts were densified at temperatures ranging from 1800 to 2100 C. Optimum densification temperatures will probably be in the 1900 to 2000 C range based on these preliminary results which showed that 2050 C samples had experienced substantial grain growth. Although overfired, the 2050 C samples exhibited excellent mechanical properties. Biaxial tensile strengths up to 714 MPa and Vickers hardness values of 2430 kg/sq mm 2 were both more typical of hot pressed than sintered SiC. Both result from the absence of large defects and the confinement of residual porosity (less than 2.5%) to small diameter, uniformly distributed pores.

Method for producing microcomposite powders using a soap solution

DOEpatents

Maginnis, Michael A.; Robinson, David A.

1996-01-01

A method for producing microcomposite powders for use in superconducting and non-superconducting applications. A particular method to produce microcomposite powders for use in superconducting applications includes the steps of: (a) preparing a solution including ammonium soap; (b) dissolving a preselected amount of a soluble metallic such as silver nitrate in the solution including ammonium soap to form a first solution; (c) adding a primary phase material such as a single phase YBC superconducting material in particle form to the first solution; (d) preparing a second solution formed from a mixture of a weak acid and an alkyl-mono-ether; (e) adding the second solution to the first solution to form a resultant mixture; (f) allowing the resultant mixture to set until the resultant mixture begins to cloud and thicken into a gel precipitating around individual particles of the primary phase material; (g) thereafter drying the resultant mixture to form a YBC superconducting material/silver nitrate precursor powder; and (h) calcining the YBC superconducting material/silver nitrate precursor powder to convert the silver nitrate to silver and thereby form a YBC/silver microcomposite powder wherein the silver is substantially uniformly dispersed in the matrix of the YBC material.

Method for producing silicon nitride/silicon carbide composite

DOEpatents

Dunmead, Stephen D.; Weimer, Alan W.; Carroll, Daniel F.; Eisman, Glenn A.; Cochran, Gene A.; Susnitzky, David W.; Beaman, Donald R.; Nilsen, Kevin J.

1996-07-23

Silicon carbide/silicon nitride composites are prepared by carbothermal reduction of crystalline silica powder, carbon powder and optionally crsytalline silicon nitride powder. The crystalline silicon carbide portion of the composite has a mean number diameter less than about 700 nanometers and contains nitrogen.

The Remote Food Photography Method accurately estimates dry powdered foods—the source of calories for many infants

PubMed Central

Duhé, Abby F.; Gilmore, L. Anne; Burton, Jeffrey H.; Martin, Corby K.; Redman, Leanne M.

2016-01-01

Background Infant formula is a major source of nutrition for infants with over half of all infants in the United States consuming infant formula exclusively or in combination with breast milk. The energy in infant powdered formula is derived from the powder and not the water making it necessary to develop methods that can accurately estimate the amount of powder used prior to reconstitution. Objective To assess the use of the Remote Food Photography Method (RFPM) to accurately estimate the weight of infant powdered formula before reconstitution among the standard serving sizes. Methods For each serving size (1-scoop, 2-scoop, 3-scoop, and 4-scoop), a set of seven test bottles and photographs were prepared including the recommended gram weight of powdered formula of the respective serving size by the manufacturer, three bottles and photographs containing 15%, 10%, and 5% less powdered formula than recommended, and three bottles and photographs containing 5%, 10%, and 15% more powdered formula than recommended (n=28). Ratio estimates of the test photographs as compared to standard photographs were obtained using standard RFPM analysis procedures. The ratio estimates and the United States Department of Agriculture (USDA) data tables were used to generate food and nutrient information to provide the RFPM estimates. Statistical Analyses Performed Equivalence testing using the two one-sided t- test (TOST) approach was used to determine equivalence between the actual gram weights and the RFPM estimated weights for all samples, within each serving size, and within under-prepared and over-prepared bottles. Results For all bottles, the gram weights estimated by the RFPM were within 5% equivalence bounds with a slight under-estimation of 0.05 g (90% CI [−0.49, 0.40]; p<0.001) and mean percent error ranging between 0.32% and 1.58% among the four serving sizes. Conclusion The maximum observed mean error was an overestimation of 1.58% of powdered formula by the RFPM under controlled laboratory conditions indicating that the RFPM accurately estimated infant powdered formula. PMID:26947889

Formation of Bi2Sr2CaCu2O x /Ag multifilamentary metallic precursor powder-in-tube wires

NASA Astrophysics Data System (ADS)

Zhang, Yun; Koch, Carl C.; Schwartz, Justin

2016-12-01

Previously, a metallic precursor (MP) approach to synthesizing Bi2Sr2CaCu2O x (Bi2212), with a homogeneous mixture of Bi, Sr, Ca, Cu and Ag was produced by mechanical alloying. Here, Bi2212/Ag round multifilamentary wire is manufactured using a metallic precursor powder-in-tube (MPIT) process. The MP powders were packed into a pure Ag tube in an Ar atmosphere and then sealed. After deformation, multifilamentary round wires and rolled tapes were heat treated in flowing oxygen through three stages: oxidation, conversion and partial-melt processing (PMP). Processing-microstructure-property relationships on 20-50 mm long multifilamentary round wires and rolled tapes were studied extensively. It is shown that conventional wire deformation processes, optimized for oxide-powder-in-tube wires, are not effective for deforming MPIT wires, and that as with prior studies of MPIT Bi2Sr2Ca2Cu3O y conductors, hot extrusion is required for obtaining a multifilamentary structure with fine filaments. As a result, the Bi2212 MPIT wires reported here have low engineering critical current density. Nonetheless, by focusing on sections of wires that remain intact after deformation, it is also shown that the first heat treatment stage, the oxidation stage, plays a crucial role in chemical homogeneity, phase transformation, and microstructural evolution and three reaction pathways for MP oxidation are presented. Furthermore, it is found the Bi2212 grain alignment within an MPIT filament is significantly different from that found in OPIT filaments after PMP, indicating the formation of highly dense filaments containing Bi2212 fine grains and Ag particles before PMP aids the formation of large, c-axis textured Bi2212 filaments during PMP. These results show that, with improved wire deformation, high critical current density may be obtained via a MPIT process.

The analysis of carbohydrates in milk powder by a new "heart-cutting" two-dimensional liquid chromatography method.

PubMed

Ma, Jing; Hou, Xiaofang; Zhang, Bing; Wang, Yunan; He, Langchong

2014-03-01

In this study, a new"heart-cutting" two-dimensional liquid chromatography method for the simultaneous determination of carbohydrate contents in milk powder was presented. In this two dimensional liquid chromatography system, a Venusil XBP-C4 analysis column was used in the first dimension ((1)D) as a pre-separation column, a ZORBAX carbohydrates analysis column was used in the second dimension ((2)D) as a final-analysis column. The whole process was completed in less than 35min without a particular sample preparation procedure. The capability of the new two dimensional HPLC method was demonstrated in the determination of carbohydrates in various brands of milk powder samples. A conventional one dimensional chromatography method was also proposed. The two proposed methods were both validated in terms of linearity, limits of detection, accuracy and precision. The comparison between the results obtained with the two methods showed that the new and completely automated two dimensional liquid chromatography method is more suitable for milk powder sample because of its online cleanup effect involved. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

Applying Massively Parallel Kinetic Monte Carlo Methods to Simulate Grain Growth and Sintering in Powdered Metals

DTIC Science & Technology

2011-09-01

Structure Evolution During Sintering From [19]. ...................................20 Figure 10. Ising Model Configuration With Eight Nearest Neighbors...INTRODUCTION A. MOTIVATION The ability to fabricate structural components from metals with a fine (micron- sized), controlled grain size is one of the...hallmarks of modern, structural metallurgy. Powder metallurgy, in particular, consists of powder manufacture, powder blending, compacting, and sintering

Fast and selective determination of total protein in milk powder via titration of moving reaction boundary electrophoresis.

PubMed

Guo, Cheng-ye; Wang, Hou-yu; Liu, Xiao-ping; Fan, Liu-yin; Zhang, Lei; Cao, Cheng-xi

2013-05-01

In this paper, moving reaction boundary titration (MRBT) was developed for rapid and accurate quantification of total protein in infant milk powder, from the concept of moving reaction boundary (MRB) electrophoresis. In the method, the MRB was formed by the hydroxide ions and the acidic residues of milk proteins immobilized via cross-linked polyacrylamide gel (PAG), an acid-base indicator was used to denote the boundary motion. As a proof of concept, we chose five brands of infant milk powders to study the feasibility of MRBT method. The calibration curve of MRB velocity versus logarithmic total protein content of infant milk powder sample was established based on the visual signal of MRB motion as a function of logarithmic milk protein content. Weak influence of nonprotein nitrogen (NPN) reagents (e.g., melamine and urea) on MRBT method was observed, due to the fact that MRB was formed with hydroxide ions and the acidic residues of captured milk proteins, rather than the alkaline residues or the NPN reagents added. The total protein contents in infant milk powder samples detected via the MRBT method were in good agreement with those achieved by the classic Kjeldahl method. In addition, the developed method had much faster measuring speed compared with the Kjeldahl method. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Use of bauxite as packing material in steam injection wells

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

Scoglio, J.; Joubert, G.; Gallardo, B.

1995-12-31

Cyclic steam injection, also known as steam soak, has proven to be the most efficient method for producing heavy crude oil and bitumen from unconsolidated sands. The application of steam injection may, however, generate sand production, causing, among other things, a decrease in production. The gravel pack technique is the most efficient way to prevent fines production from cold producing wells. But, once they are steam stimulated, a dissolution of quartz containing gravel material takes place reducing greatly the packing permeability and eventually sand production. Different types of packing material have been used to avoid sand production after cyclic steammore » injection, such as gravel, ceramics, bauxite, coated resin, and American sand. This paper presents the results of field test, using sinterized bauxite as a packing material, carried out in Venezuela`s heavy oil operations as a part of a comprehensive program aimed at increasing the packing durability and reducing sand production. This paper also verify the results of laboratory tests in which Bauxite was found to be less soluble than other packing material when steam injected.« less

Valve leakage inspection, testing, and maintenance process

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

Aikin, J.A.; Reinwald, J.W.

1989-01-01

Atomic Energy of Canada Limited-Research Company (AECL-RC), Chalk River, has more than 50 person-years dedicated toward the leak-free valve. In the early 1970s, the Chalk River Nuclear Laboratories (CRNL) developed valve stem live-loading and recently completed the packing tests for the Electric Power Research Institute (EPRI)-funded Valve Packing Improvement Study. Current safety concerns with asbestos-based valve packings and the difficulty in removing newer graphite packings prompted CRNL to investigate methods to improve valve repacking procedures. The present practice of valve packing replacement is very labor-intensive, requiring use of hand tools such as corkscrew devices and special packing picks. Use ofmore » water jets to cut or fragment the packing for withdrawal from the stuffing box does improve the process, but removal of the lantern or junk rings is still difficult. To address these problems, AECL-RC has developed a unique valve maintenance process designed to reduce person-rem exposures, the risk of scoring the stem or stuffing box, and maintenance costs and to improve the engineering quality of valve repair.« less

Enhanced method of magnetic powder alignment for production of PLP Nd-Fe-B magnets

NASA Astrophysics Data System (ADS)

Popov, A. G.; Golovnia, O. A.; Protasov, A. V.

2017-04-01

It is demonstrated how the high degree of powder alignment in PLP magnets can be achieved by loading the powder into a container placed in a magnetic field of moderate strength. The strip-cast alloy with a composition of 30.00 Nd, 1.95 Dy, 66.42 Fe, 0.99 B, 0.54 Co, 0.1 Ga (wt%) was subjected to hydrogen decrepitation and then milled in a vibratory mill in toluene to an average particle size of 2.9 μm determined by the FSSS method. The powder was compacted in the magnetic field of 0.2 - 1.2 T to the filling density 2.6 - 3.2×103 kg/m3. It is shown that loading the powder into a container placed in a magnetic field enhances the degree of powder alignment in sintered Nd-Fe-B magnets produced from non-pressed powder. At the filling density less than 3.2×103 kg/m3, the density of magnets is high but insufficient, because of the formation of magnetostatic chains of particles, which impedes the powder compaction. The simulation by the discrete-element method qualitatively proves that the magnetostatic interaction of the chains of particles that are formed in the course of loading in the magnetic field stimulates a decrease in the density of the sintered magnets and its non-uniform distribution over the sample. As a result of the optimization of the parameters of the alignment and compaction of the powder loaded in a magnetic field, PLP magnets with Br ≥1.34 T, Hc ≥950 kA/m, (BH)max ≥340 kJ/m3, and the degree of alignment exceeding 96% were produced.

Comparison of different drying methods on the physical properties, bioactive compounds and antioxidant activity of raspberry powders.

PubMed

Si, Xu; Chen, Qinqin; Bi, Jinfeng; Wu, Xinye; Yi, Jianyong; Zhou, Linyan; Li, Zhaolu

2016-04-01

Dehydration has been considered as one of the traditional but most effective techniques for perishable fruits. Raspberry powders obtained after dehydration can be added as ingredients into food formulations such as bakery and dairy products. In this study, raspberry powders obtained by hot air drying (HAD), infrared radiation drying (IRD), hot air and explosion puffing drying (HA-EPD), infrared radiation and microwave vacuum drying (IR-MVD) and freeze drying (FD) were compared on physical properties, bioactive compounds and antioxidant activity. Drying techniques affected the physical properties, bioactive compounds and antioxidant activity of raspberry powders greatly. FD led to significantly higher (P < 0.05) values of water solubility (45.26%), soluble solid (63.46%), hygroscopicity (18.06%), color parameters and anthocyanin retention (60.70%) of raspberry powder compared with other drying methods. However, thermal drying techniques, especially combined drying methods, were superior to FD in final total polyphenol content, total flavonoid content and antioxidant activity. The combined drying methods, especially IR-MVD, showed the highest total polyphenol content (123.22 g GAE kg(-1) dw) and total flavonoid content (0.30 g CAE kg(-1) dw). Additionally, IR-MVD performed better in antioxidant activity retention. Overall, combined drying methods, especially IR-MVD, were found to result in better quality of raspberry powders among the thermal drying techniques. IR-MVD could be recommended for use in the drying industry because of its advantages in time saving and nutrient retention. © 2015 Society of Chemical Industry.

INFLUENCES OF PH AND CURRENT ON ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE AT A GRANULAR-GRAPHITE PACKED ELECTRODE

EPA Science Inventory

Electrolytic dechlorination using a granular-graphite packed cathode is an alternative method for the remediation of chlorinated organic compounds. Its effectiveness under various conditions needs experimental investigation. Dechlorination of trichloroethylene (TCE) was conducted...