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Phase IV Engineering, Inc.
Boulder, CO, United States
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Colorado H.A.,University of California at Los Angeles | Colorado H.A.,University of Medellín | Colorado H.A.,Phase IV Engineering, Inc. | Hiel C.,Composite Support and Solutions Inc. | Hahn H.T.,University of California at Los Angeles
Bulletin of Materials Science | Year: 2011

Mechanical properties and microstructures of a chemically bonded phosphate ceramic (CBPC) and its composite with 1.0 wt% graphite nanoplatelets (GNPs) reinforcement have been investigated. Microstructure was identified by using optical and scanning electron microscopes, X-ray tomography, and X-ray diffraction. In addition, weight loss of the resin at room temperature was studied. The microstructure characterization shows that CBPC is itself a composite with several crystalline (wollastonite and brushite) and amorphous phases. SEM and micro tomography show a homogeneous distribution of crystalline phases. Bending and compression strength of the CBPC was improved by reducing bubbles via preparation in vacuum. © Indian Academy of Sciences.

Kim H.C.,Korea Atomic Energy Research Institute | Hahn H.T.,Phase IV Engineering, Inc. | Yang Y.S.,Korea Atomic Energy Research Institute
Journal of Composite Materials | Year: 2013

In an effort to fabricate prototypes with improved mechanical properties in the selective laser sintering process, functionalized graphite nanoplatelets were added to polyamide-12 powder to produce a nanocomposite powder. The polyamide-12 powder was chosen as the matrix polymer because it has features conducive to laser sintering, such as a low melting temperature and high mechanical properties. As fillers, the graphite nanoplatelets were oxidized through a nitric acid treatment to improve the interfacial bonding. For the syntheses of the nanocomposite solution, intercalation in an autoclave was conducted to obtain good dispersion and manufacturability. The micro/nanostructures of the synthesized nanocomposites were examined through scanning electron microscopy. The distribution of particles was also analyzed to look at the feasibility for the selective laser sintering process. The synthesized nanocomposite powder was layered and sintered by a laser. The mechanical properties for specimens made of neat polyamide-12, polyamide-12/TiO2, and polyamide-12/functionalized graphite nanoplatelet were tested and compared. The results indicate that the functionalization of nanofiller reinforces interfacial bonding force. For this reason, a small amount of nanofiller, which does not influence the thermal and rheological behavior, can improve the material properties. © The Author(s) 2012.

Manvar A.T.,Saurashtra University | Virsodia V.R.,Jubilant Organosys | Upadhyay K.D.,Torrent Research Center | Manvar D.R.,Jubilant Organosys | And 5 more authors.
Molecular Diversity | Year: 2010

In continuation of our research program on new antitubercular agents, this article is a report of the synthesis of 97 various symmetrical, unsymmetrical, and N-substituted 1,4-dihydropyridines. The synthesized molecules were tested for their activity against M. tuberculosis H 37Rv strain with rifampin as the standard drug. The percentage inhibition was found in the range 3-93%. In an effort to understand the relationship between structure and activity, 3D-QSAR studies were also carried out on a subset that is representative of the molecules synthesized. For the generation of the QSAR models, a training set of 35 diverse molecules representing the synthesized molecules was utilized. The molecules were aligned using the atom-fit technique. The CoMFA and CoMSIA models generated on the molecules aligned by the atom-fit method show a correlation coefficient (r 2) of 0.98 and 0.95 with cross-validated r 2(q 2) of 0.56 and 0.62, respectively. The 3D-QSAR models were externally validated against a test set of 19 molecules (aligned previously with the training set) for which the predictive r 2(r 2 pred) is recorded as 0.74 and 0.69 for the CoMFA and CoMSIA models, respectively. The models were checked for chance correlation through y-scrambling. The QSAR models revealed the importance of the conformational flexibility of the substituents in antitubercular activity.

Pathak D.,Eden Hospital | Pathak D.,Phase IV Engineering, Inc. | Chakraborty B.,Eden Hospital | Goswami S.,Eden Hospital | Adhikari S.,Eden Hospital
Journal of Obstetrics and Gynecology of India | Year: 2011

Objective: To study the difference in causes of maternal deaths at two tertiary centers one being rural and the other urban. Methods: A five years retrospective study from January 2001 to December 2005. Results: The maternal mortality ratio has decreased at Eden (6.09 to 2.81/1000 live births) and risen at Bankura (2.68 to 4.18/1000 live births) over the last five years. Most of the deaths were in the age group of 21-30 (65.48% and 60.62%) and unbooked (81.14% and 67.71%) at Eden and Bankura respectively. Greater number of deaths were noted in early puerperium (68.58% vs. 37.79%) and in multigravidas (71.68% vs. 50.78%) at Eden. Sepsis (30.70%) and jaundice (30.08%) were the major causes of death at Bankura and Eden respectively. Death due to toxaemia has gradually decreased. Conclusion: Majority of the deaths are preventable by proper antenatal care, counseling and asepsis practice. Antenatal care and EmOC are complementary to each other in reducing maternal mortality. © 2011 Federation of Obstetrics and Gynaecological Societies of India (FOGSI).

Abbasi S.,Phase IV Engineering, Inc. | Healy P.,University of Limerick | Rextin A.,University of Limerick
Information Processing Letters | Year: 2010

We consider the standard algorithm by Bertolazzi et al. to test the upward planarity of embedded digraphs. We show how to improve its running time from O (n + r2) to O (n + rfrac(3, 2)), where r is the number of sources and sinks in the digraph. We also discuss an application of this technique: improving the running time of getting a quasi-upward planar drawing for an embedded digraph with minimum number of bends. © 2010 Elsevier B.V. All rights reserved.

Kuester D.,Phase IV Engineering, Inc. | Popovic Z.,University of Colorado at Colorado Springs
IEEE Microwave Magazine | Year: 2013

Passive ultra-high-frequency (UHF) radio-frequency identification (RFID) has developed rapidly over the past two decades. In 2012 alone, about 4 billion tags were sold worldwide [1]. Manufacture and deployment at this volume has been made possible by minimizing tag cost, making a strong disincentive for the added expense of RF performance testing. As a result, performance metrics and test methods are not yet unified or generally adopted. Large customers in industry and government, however, wish to compare products with parameters like read range and inventory rate, so this problem is attracting more attention, and test standards are improving. This article discusses the history, state of the art, and some future challenges in this rapidly evolving area of study. In particular, we consider two metrics for digitally modulated backscatter of passive UHF RFID tags and how tests can be simplified for reduced costs. Examples for some 860-960 MHz commercial tags and applications are given to illustrate the method. © 2000-2012 IEEE.

Yusoff A.R.B.M.,Federal University of Paraná | Shuib S.A.,Phase IV Engineering, Inc.
Electrochimica Acta | Year: 2011

In this paper, we present a simple method for electropolymerization process that combines aniline-silane (C6H5NHC3H 6Si(OMe)3) surface modified indium-tin-oxide (ITO) to prepare thin, polyaniline (PANI) films with good surface coverage. The modified surface enhances the growth of PANI film resulting in a smoother surface, dense, strongly adhered film, higher electropolymerization activity and stability than those deposited on unmodified ITO substrates. PANI film deposited on modified ITO substrate was used as a modified base terminal in a metal-base-transistor (MBT), which used tris(8-hydroxyquinoline) aluminum (Alq3) as an emitter layer, LiF as a buffer layer, and Al as a cathode. The MBT, tested at in ambient atmosphere, and without the presence of magnetic-field, has a comparable but stable current gain, 6.5 than that of a device with a sulfonated polyaniline (SPANI) based metal-base transistor. With this simple and easy electropolymerization method, the on-to-off current ratio achieved 6.9 × 104. © 2011 Elsevier Ltd. All rights reserved.

Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase I | Award Amount: 99.69K | Year: 2012

A novel passive RFID temperature sensor that is attached or embedded in large caliber ammunition to automatically provide actual propellant temperature to fire control computers in real time.

Pillai M.G.,Phase IV Engineering, Inc. | Kumar A.,Phase IV Engineering, Inc. | Sharma R.,Phase IV Engineering, Inc. | Bhasin N.,Phase IV Engineering, Inc.
Chromatographia | Year: 2014

Hydrastis canadensis L. is one of the important herbal medicinal plants, which is used for homeopathic preparations. It contains berberine, hydrastine as major and canadine, hydrastinine, berberastine and canadaline as minor bioactive compounds. The aim was to develop (I) a sensitive mass spectrometric-based quantitative/qualitative method for berberine in homeopathic dilutions of H. canadensis, (II) with identification of berberine and its structurally related compound present in the homeopathic preparation of H. canadensis using predictive MRM workflow, (III) confirmatory analysis for the structurally related compound in homeopathic dilutions of H. canadensis using high-resolution mass spectrometer. Different mass spectrometric-based workflows (MRM to EPI; pMRM to EPI and IDA-DBS) were used to develop the method to analyze the homeopathic dilutions of H. canadensis. A high-throughput liquid chromatography-tandem mass spectrometry method using MRM to EPI workflow was developed to analyze berberine in homeopathic preparation of H. canadensis. Multiple reaction monitoring transitions of 336.0/292.08 and 336.0/277.9 were selected for developing the quantitation method of berberine. The method was linear from 5.0 to 2000.0 pg/mL. The validated method has been successfully applied for the analysis of different potencies of homeopathic preparation of H. canadensis. Predictive MRM to enhanced product ion workflows was used to identify and confirm the structurally related molecules of berberine. Non targeted information dependent acquisition-DBS method was developed to identify the compounds in H. canadensis mother tincture using high-resolution mass spectrometry. The established method using different mass spectrometric workflows facilitates the convenient and fast quality control analysis for the herbal preparation of H. canadensis. © 2013 Springer-Verlag Berlin Heidelberg.

Agency: Department of Defense | Branch: Army | Program: SBIR | Phase: Phase II | Award Amount: 496.05K | Year: 2014

In this project a Radio Frequency Identification (RFID) temperature tag and reader system will be developed. The tag will be easily applied to large caliber ammunition such as artillery propellant. Readers will be attached to guns or be located in handling areas. When the propellant is passed near the reader, an accurate temperature will be read and passed in real time to the fire control system.

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