Weight Percent Composition Research Articles

Structural, optical and antifungal properties of the PMMA-ZnO nanocomposites: Potential applications in odontology

PMMA-ZnO nanocomposites were synthesized with different percent weight compositions of as synthesized ZnO nanoparticles (2%, 2.5%, 3.5%. 4.5% and 5% w/w). Further their structural and optical properties were investigated using XRD, SEM and UV–vis spectrophotometer. No significant peak of ZnO crystalline phase in all the samples of PMMA-ZnO nanocomposites was observed in XRD study which refers the complete dispersion of it within the solution and confirms the formation of nanocomposites. However, UV–vis spectroscopy study shows an intense absorbtion at wavelength 377 nm in all samples of PMMA-ZnO nanocomposites of various weight percent compositions and its absorbance increases with increase in the percent weight composition of nanofiller in the nanocomposites which attributes the presence of ZnO nanoparticles. FESEM study reveals the uniform distribution of ZnO nanoparticles with average particle size 25 nm throughout the PMMA matrix. The EDX spectra of PMMA-ZnO nanocomposites demonstrate the presence of ZnO NPs in the nanocomposites. The antifungal efficacies of the newly developed materials were evaluated in details both quantitatively and qualitatively by minimum inhibitory concentration (MIC) and zone of inhibition methods against four different Candida species. PMMA-ZnO nanocomposites show the highest antifungal activity at percent weight compositions of ZnO NPs in the range of 3.5%–4.5% while no significant antifungal activity was observed in the nanocomposite samples at lower weight percent compositions of ZnO NPs in the range of 0.3%–1.5%. ZnO nanofillers incorporated PMMA nanocomposites improves its antifungal efficacy significantly against various Candida species, suggesting it a smart denture base material to combat denture stomatitis like diseases.

Design of higher temperature copper brazing filler metals with reduced brittle phase content

Anneal-resistant copper alloys have been developed to address the need for stronger yet lighter fin and tube parts in heat exchangers, in order to facilitate greater efficiency and increased temperature capability. As such, brazing as opposed to traditional soldering has become the preferred joining method for these materials, due to the enhanced high-temperature properties of such joints. Copper-based filler metals are used extensively for the brazing of these materials, generally based on the copper-phosphorus system with alloying additions. In the present study, the microstructural issues arising from the current commercially available filler metals are discussed and addressed through CALPHAD-supported alloy design. Three selected novel compositions were used in the brazing of pure copper as a test of the design concept. Alloy compositions in weight percent of Cu(bal.)− 7Ni-4Sn-5 P and Cu(bal.)-10Ni-2Sn-6.5 P were found to result in a reduction of brittle Cu3P phase while increasing the fraction (0.78 and 0.77 respectively) of copper-rich solid solution in joints post-braze, comparing favourably to commercial Meta-Braze™ 077 under similar conditions (0.61). Furthermore, the copper-rich solid solution was leaner in tin, predicted to impart an increased melting temperature while microhardness profiles indicate increased joint ductility. The implications for mechanical properties of filler metals in this alloy family are discussed.

Comparison of Different Synthesis Methods to Obtain GDC as Nanoparticulated Electrolytic Material for SOFCs Operating at Intermediate Temperature (~500°C)

The necessary global electrical energy demand employs a high amount of fossil fuels and produces emissions of polluting gases due to its combustion, which needs the improving of the electric power generation technologies friendlier with the environment. This technology must guarantee to be sustainable, economic and available for all people. The SOFCs represent a promising alternative in the production of electrical energy directly from chemical energy through a series of electrochemical reactions with the use of fuels as hydrogen, carbon monoxide, methane and several synthesis gases rich in hydrogen or methane.The development of SOFCs has several challenges, related with thermic and electrochemical properties of the materials that constitutes anode, cathode and electrolyte. Several materials has been tested, for instance perovskites, aiming for facilitate the ionic conductivity inside these cells and reduce the operating temperatures, also looking for the increase of performance. To get similar thermal expansion coefficients (TEC) in anode, electrolyte and cathode, researchers have tested different chemical compositions to modify the perovskite structure of materials utilized in these components for SOFCs. Specifically for the electrolyte, these modifications could enhance the creation of oxygen vacancies, contributing to decrease TEC and also reduce the cathodic polarization, which are IT-SOFC operating challenges.Aiming for solve these issues, in this work, the synthesis of a cobaltite of lanthanum type perovskite LSCF, as cathode material, is developed by the co-precipitation method, using nitrate precursors. Also GDC is synthetized by three synthesis methods, which is the main purpose of this work: co-precipitation, sol-gel combustion (SGC) and hydrothermal. The obtained compounds are characterized physical and chemically by FTIR, TGA, TEM, SEM-EDS, and XRD.GDC synthesis was carried out by three different synthesis routes (SGC, Hydrothermal and Co-precipitation). The analysis of the mapping with EDS showed the uniform presence of each of the components Ce, Gd and O in the entire sample, in all the studied cases. In addition, the chemical composition in weight percent (% wt) by zones was evaluated to delimit the compositional homogeneity of the sample, but two different compositions were found that were replicated in all the extent of the powder, (1) Ce0,8Gd0,2O1,9 and (2) Ce0,7Gd0,3O1,85, as possible, which was corroborated with XRD analysis, in addition, the sample is crystalline and organized, the crystallinity decreases as follows SGC> Co-precipitation> Hydrothermal; this is defined as well, since the peaks are more defined and narrow in that order, whereas powders obtained by SGC are considered more crystalline than those obtained by the other two routes. Furthermore, similar stoichiometries of these compounds can be used in this type of fuel cell, since both have been used before.In all the cases studied, FTIR analysis show the characteristic adsorption band of GDC, which is normally at 565 cm-1, and is assigned to vibrations by elongation between metal and oxygen, which in this case would be the Ce bonds, -O and / or Gd-O. On the other hand, with TEM analysis corroborate that all the powders obtained with GDC synthesis have a nanometric size. The particle size obtained in decreasing order was SGC> Co-precipitation> Hydrothermal.The obtained results in this work show that GDC electrolytes are dependent of the synthesis route, but in general have adequate physical and chemical properties to be applied with good performance in IT-SOFCs. Considering this, currently we are building a single IT-SOFC with these materials to test at 500°C.

Influences of subphase pH and temperature on the interfacial aggregation behavior of poly(lauryl methacrylate)-block-poly(methacrylic acid)

We previously reported that poly(acrylic acid) (PAA) blocks at the air/water interface spontaneously immersed into water at high pH before monolayer compression. To investigate the influence of the hydrophobic methyl groups in poly(methacrylic acid) (PMAA) blocks, in this work, subphase pH and temperature effects on the aggregation behaviors of two pH-responsive amphiphilic diblock copolymers poly(lauryl methacrylate)-block-poly(methacrylic acid) (PLMA-b-PMAA) (PLMA49%-PMAA and PLMA61%-PMAA, composition in weight percent) at the air/water interface were studied. The surface pressure–molecular area isotherms of the two copolymers move to small mean molecular area (mma) as subphase pH increases and a quasi-plateau exists under various subphase conditions, which is quite different from its absence in our previous PAA-containing block copolymer system. The quasi-plateau is attributed to the pancake-to-brush transition as non-ionized PMAA chains submerge into subphase upon monolayer compression. Under acidic condition, PMAA chains of the two copolymers are almost non-ionized, the compression and expansion isotherms show large hysteresis phenomena. Under neutral and alkaline conditions, the isotherms show small hysteresis, which is because more ionized PMAA chains immerse in subphase before compression. The isotherms shift toward small mma with increasing temperature under neutral and alkaline conditions, whereas a slight shift back to large mma is observed under acidic conditions. The plateau surface pressures of the two PLMA-b-PMAA copolymers decrease with increasing temperature under different pH conditions, which is because the micelles move more freely and easier to rearrange at high temperature. The plateau surface pressures of PLMA49%-PMAA are higher than those of PLMA61%-PMAA under the corresponding conditions due to the higher PMAA content in the former. The initial Langmuir–Blodgett (LB) films of the two copolymers transferred under different pH conditions at various temperatures exhibit isolated circular micelles because of the steric hindrance and/or repulsive interactions among the long PMAA chains. Furthermore, temperature has almost no effect on the micelle core diameters of the initial LB films.

Optimization and Experimental Validation of Automotive Bulbs

In a vehicle, bulbs called the P-group are responsible for warning other drivers or pedestrians and they are known as signal bulbs. Signal bulbs have been used to emit warning and hazard signs in parts such as brake lights, direction indicator, hazard lights (night vision) as well as tail bulbs and car park alarms. There has been limited researches on the photometric characteristics of these lamps, but a review of these studies revealed that no detailed research has yet been done on optimizing these characteristics, and there is a scientific gap. In this study, factors affecting the service life and luminous flux were evaluated by using Taguchi design of experiments method. The results showed that the two factors of weight percent composition of bubble filling neutral gases and the volumetric efficiency of gases injected into the bubble had the most influence on the target parameters. Experimental results showed that the optimum composition of neutral gases injected into the bulb bubble can extend the bulb service life to approximately 341 h, which is three times the service life of a bulb with the inappropriate composition of fill gases. Then the optimum state of the service life and the luminous flux were determined to meet the reference standards. Although the service life and luminous flux parameters were able to reach 341 h and 513 lumens in the maximized state, however, in the optimum state with satisfying reference standards, the service life and luminous flux were 330 h and 463 lumens, respectively. Then, the bulb bubble filling with inert neutral gases and its effect on the bulb service life was investigated. The results showed that if the volumetric efficiency of gas injection increased from the normal 75%–100%, the service life of the test lamps would be improved by about 10%.

Crystal structure and corrosion properties of alumunium organoclay composite by the hotpress method

Alumunium Matrix Composite (AMC) is a material that has great potential especially in automotive industry. AMC has good corrosion resistance, density, electrical conductivity and heat properties. This paper will study the crystal structure form composite materials and the corrosion properties of the sample. Composite material made with Alumunium as a matrix and reinforcement in the of organoclay variations 0%, 1%, 2%, 3% wt by the hotpress method at 600°C for 1 hour. Characterization of crystal structure and phase using X-Ray diffraction. The corrosion properties of the samples were examine by potentiodynamic curves in 3,5 % wt NaCl solution. The results showed that the addition of weight percent composition of organoclay produce different characteristics and corrosion properties. Corrosion properties can be seen form the rate of corrosion slower along with the addition composition of the organoclay. The smallest corrosion rate results found in alumunium composites with reinforcement variations of 3% by 1,776 x 10−4 mm/year.

Analysis of quenching heat treatment, martemper on structure micro and hardness in SCMn3 steel.

Microstructure analysis and hardness analysis has been carried out on cast steel for components of soil digging machines due to heat treatment of quench, and martemper. The presence of residual austenite causes wear resistance and reduced fracture strength in the earth quarry component to function as a support for the designed arm. In its manufacture, it uses metal casting technology and heat quenching treatments and templates in suitable cooling media, to meet standard requirements. The temperature treatment of austenite 875 °C temperature was held for 90 minutes, and then quenched with variations in the cooling media of water, oil, and salt bath. Furthermore, the martemper process at 425 °C for 90 minutes is cooled to air to room temperature. Microstructure testing and weight percent composition using SEM-EDX and Brihnell scale hardness test. The analysis shows that the hardness value (388 HB) of cast steel quenched in salt bath media is greater than ordinary water (299 HB) and oil (260 HB). However, after the martemper process the value of hardness drops to (342 HB) in the salt water medium, which remains larger than ordinary water (264 HB) and oil (233 HB). This is due to the faster cooling speed in brine and produces martensitic microstructure and residual austenite after being observed with SEM-EDX. The results of this study meet the quality requirements according to the JIS G5111 standard where the minimum hardness value is 222 HB, to be used as a component in excavator.

Effect of carbon on the hydrodesulfurization activity of MoCo catalysts supported on zeolite/ active carbon hybrid supports

A series of catalysts of cobalt (Co) and molybdenum (Mo) loaded on zeolite (Z) support decorated with different weight percent of activated carbon (AC), namely ZMoCo, ZACMoCo25%, ZACMoCo50%, and ZACMoCo75%, were newly prepared, characterized by using various techniques to reveal the structural, textural, surface composition and thermal behavior of both hybrid supports and supported bimetallic catalysts, followed by the evaluation of the supported bimetallic catalysts in ultra-deep hydrodesulfurization reaction. The loading of Co and Mo nanoparticles, as well as carbon, perturbed the zeolite lattice, but the structural crystallinity was largely preserved with low weight percent composition of carbon in the hybrid supports. The ZAC75% hybrid support showed significant loss of crystallinity, but this seemed to be largely redeemed with the incorporation of Co and Mo nanoparticles, as in the case of ZACMoCo75%. The progressive decrease in relative crystallinity (RC) with an increase in the amount of carbon, in both hybrid supports and supported bimetallic catalysts, could be due to the dilution effect of the hybrid supports. Importantly, the decoration of Y zeolite with carbon from waste rubber tyre offered a new metal-free approach to modify zeolite support for hydrodesulfurization MoCo catalysts. Optimum loading of carbon onto zeolite support offered uniform mesoporous structure, moderate acidity, and better active metal dispersion in the carbon-decorated zeolite-supported MoCo catalysts. The hybrid support ZAC50% showed better dispersion of metal nanoparticles to form ZACMoCo50% with preserved structural, textural and surface functionalities and reduced acidity that enabled its better performance of 98% conversion (turn over number, TON, of 7.84 at 6 h reaction time) in hydrodesulfurization of model fuel.

Comprehensive characterization of printed circuit boards of various end-of-life electrical and electronic equipment for beneficiation investigation

Comprehensive characterization of printed circuit board (PCB) of end-of-life electrical and electronic equipment (EEE) is obligatory for prospective profitable beneficiation. In this study, beneficiation oriented comprehensive characterization of two brands of PCBs each of 16 end-of-life EEE was conducted in terms of their physicochemical characteristics with special emphasis on the content of 16 general elements, 2 precious metals and 15 rare earth elements (REEs). General elements and their highest weight percent composition found in different PCBs of the EEEs were Cu (23% in laptop), Al (6% in computer), Pb (15% in DVD player) and Ba (7% in TV). The high abundant of precious metals such as Au (316 g/ton) and Ag (636 g/ton) in mobile phone and laptop, respectively coupled with rapid obsolescence age makes waste PCBs of information technology and telecommunication equipment the most potent resource reservoir. Additionally, most of the waste PCBs were observed to contain REEs in considerable quantity with Sc up to 31 g/ton and Ce up to 13 g/ton being the major constituents. Comprehensive characterization of waste PCBs therefore will systematically help towards better understanding of e-waste recycling processes for beneficiation purpose and sustainable resource circulation and conservation.

EFFECT OF HEAT TREATMENT ON THE CHARACTERISTICS OF ELECTROLESS ACTIVATED CARBON-NICKEL OXIDE NANOCOMPOSITES

Over the years, different experimental techniques have been employed to prepared activated carbon-metal oxide composite materials. However, some of these methods entail cutting-edge equipment and long processing time which may result in the destruction of the carbon structure. Electroless plating, which is a simple and efficient method, have been used to deposit nickel oxide nanoparticles on activated carbon prepared from oil palm shell (OPS) using microwave –assisted CO2 activation. The nanocomposites have been heated at various temperatures (300, 400 and 500 oC) for 1 and 2 h. The prepared activated carbon has BET surface area and total pore volume of 574.37 m2 g-1 and 0.244 cm3 g-1, respectively. The optimum heat treatment temperature has been found to be 400 oC. Also, the weight percent composition of nickel has been shown to increase with increase in treatment time.

A Constitutive Equation Relating Composition and Microstructure to Properties in Ti-6Al-4V: As Derived Using a Novel Integrated Computational Approach

While it is useful to predict properties in metallic materials based upon the composition and microstructure, the complexity of real, multi-component, and multi-phase engineering alloys presents difficulties when attempting to determine constituent-based phenomenological equations. This paper applies an approach based upon the integration of three separate modeling approaches, specifically artificial neural networks, genetic algorithms, and Monte Carlo simulations to determine a mechanism-based equation for the yield strength of α+β processed Ti-6Al-4V (all compositions in weight percent) which consists of a complex multi-phase microstructure with varying spatial and morphological distributions of the key microstructural features. Notably, this is an industrially important alloy yet an alloy for which such an equation does not exist in the published literature. The equation ultimately derived in this work not only can accurately describe the properties of the current dataset but also is consistent with the limited and dissociated information available in the literature regarding certain parameters such as intrinsic yield strength of pure hexagonal close-packed alpha titanium. In addition, this equation suggests new interesting opportunities for controlling yield strength by controlling the relative intrinsic strengths of the two phases through solid solution strengthening.

Novel Organically Modified Core-Shell Clay for Epoxy Composites-"SOBM Filler 1".

Preparation of a novel organically modified clay from spent oil base drilling mud (SOBM) that could serve as core-shell clay filler for polymers is herein reported. Due to the hydrophilic nature of clay, its compatibility with polymer matrix was made possible through modification of the surface of the core clay sample with 3-aminopropyltriethoxysilane (3-APTES) compound prior to its use. Fourier transform infrared (FT-IR) spectroscopy was used to characterize clay surface modification. Electron dispersive X-ray diffraction (EDX) and scanning electron microscopy (SEM) were used to expose filler chemical composition and morphology, while electrophoresis measurement was used to examine level of filler dispersion. Results show an agglomerated core clay powder after high temperature treatment, while EDX analysis shows that the organically modified clay is composed of chemical inhomogeneities, wherein elemental compositions in weight percent vary from one point to the other in a probe of two points. Micrographs of the 3-APTES coupled SOBM core-shell clay filler clearly show cloudy appearance, while FT-IR indicates 25% and 5% increases in fundamental vibrations band at 1014 cm−1 and 1435 cm−1, respectively. Furthermore, 3-APTES coupled core-shell clay was used to prepare epoxy composites and tested for mechanical properties.

Neutron Diffraction Measurements on Dissimilar Metal Weld of Cu-Al Obtained by Friction Stir Welding Method

Dissimilar metal weld (DMW) of Cu and Al alloy, namely DMW CuAl, was produced using Friction Stir Welding (FSW) technique. Characterization was performed at retreating and advancing side by neutron diffraction method. It is obtained that the weight percent composition of Cu and Al are dynamically change, depend on weld zone and welding direction. In SZ Cu element 55,18%, and it is majority component in the retreating side and it decreases gradually from the retreating side to the advancing side. The weight percent composition of Cu in the retreating side at HAZ and TMAZ are 99.25 %, and 61.25%, respectively, and in the advancing side are 0.35% and 38.75 %, respectively. Cu Bragg peaks of (111), (200) and (220) show that peak width ratio of BMZ / SZ is approximately 13%. This indicates a change in crystallite size that affects the behavior of plastic deformation in the welded material.

HAYNES 244 alloy – a new 760∘C capable low thermal expansion alloy

HAYNES® 244TM alloy is a new 760∘ C capable, high strength low thermal expansion (CTE) alloy. Its nominal chemical composition in weight percent is Ni – 8 Cr – 22.5 Mo – 6 W. Recently, a first mill-scale heat of 244 alloy was melted by Haynes International, and processed to various product forms such as re-forge billet, plate, and sheet. This paper presents key attributes of this new alloy (CTE, strength, low-cycle fatigue performance, oxidation resistance, thermal stability) as they pertain to the intended use in rings and seals of advanced gas turbines.

Prediction of partition coefficients of alkaloids in ionic liquids based aqueous biphasic systems using hybrid group method of data handling (GMDH) neural network

In this study, a hybrid GMDH–neural network model was developed in order to predict partition coefficients of alkaloids in aqueous biphasic system using different ionic liquids with the same inorganic salt. In order to accomplish this modeling, feed's weight percent compositions along with slope of tie-line (STL), tie-line length (TLL) and difference of molecular weight of salt and Ionic liquid were taken as the inputs and the desired partition coefficients (K) were estimated. Furthermore, the data set was divided into two parts: 80% of the data points were used for training and 20% for testing. For evaluation of the model's performance, partition coefficients obtained from the GMDH model were compared with their experimental values using different statistical measures. The proposed model can successively correlate and predict K-values and result a great agreement with the experimental data.

XMapTools: A MATLAB©-based program for electron microprobe X-ray image processing and geothermobarometry

XMapTools is a MATLAB©-based graphical user interface program for electron microprobe X-ray image processing, which can be used to estimate the pressure–temperature conditions of crystallization of minerals in metamorphic rocks. This program (available online at http://www.xmaptools.com) provides a method to standardize raw electron microprobe data and includes functions to calculate the oxide weight percent compositions for various minerals. A set of external functions is provided to calculate structural formulae from the standardized analyses as well as to estimate pressure–temperature conditions of crystallization, using empirical and semi-empirical thermobarometers from the literature. Two graphical user interface modules, Chem2D and Triplot3D, are used to plot mineral compositions into binary and ternary diagrams. As an example, the software is used to study a high-pressure Himalayan eclogite sample from the Stak massif in Pakistan. The high-pressure paragenesis consisting of omphacite and garnet has been retrogressed to a symplectitic assemblage of amphibole, plagioclase and clinopyroxene. Mineral compositions corresponding to ~165,000 analyses yield estimates for the eclogitic pressure–temperature retrograde path from 25kbar to 9kbar. Corresponding pressure–temperature maps were plotted and used to interpret the link between the equilibrium conditions of crystallization and the symplectitic microstructures. This example illustrates the usefulness of XMapTools for studying variations of the chemical composition of minerals and for retrieving information on metamorphic conditions on a microscale, towards computation of continuous pressure–temperature-and relative time path in zoned metamorphic minerals not affected by post-crystallization diffusion.

Effect of different compositions of ethylene carbonate and propylene carbonate containing iodide/triiodide redox electrolyte on the photovoltaic performance of DSSC

The effect of different compositions (in weight percent) of ethylene carbonate (EC) and propylene carbonate (PC) containing iodide/triiodide redox electrolyte on the photoelectrochemical performance of N719-sensitized nanocrystalline TiO2 solar cell was studied. The cells consisted of 0.6 M 1-hexyl-2,3-dimethylimidazolium iodide, 0.1 M LiI, 0.05 M I2 and 0.5 M 4-tert-butylpyridine in different compositions such as 1:1, 1:2, and 2:1 wt% of EC and PC. In 1:1 wt% of EC and PC containing redox electrolyte, short circuit photocurrent density (Jsc) increased and open circuit voltage (Voc) decreased. But in 1:2 and 2:1 wt% of EC and PC containing redox electrolytes, Voc increased and Jsc decreased but fill factor remained relatively constant. Dye-sensitized solar cells (DSSCs) prepared using these electrolytes give a short circuit photocurrent densities of 16.86, 12.71, and 12.09 mA/cm2; an open circuit voltages of 0.73, 0.78, and 0.79 V; fill factors of 0.63, 0.64, and 0.64; and an overall conversion efficiencies of 7.76, 6.34, and 6.13 % at an incident light of 100 mWcm−2 for 1:1, 2:1, and 1:2 wt% of EC/PC containing redox electrolytes, respectively. The incident photon-to-current conversion efficiency was higher in the case of 1:1 wt% of EC and PC containing redox electrolyte than 1:2 and 2:1 wt% of EC and PC containing redox electrolyte. It revealed that 1:1 wt% of EC and PC containing iodide/triiodide redox electrolyte is an effective electrolyte system for the fabrication of long-term stable DSSC.

Promising Pathway for Algal Biofuels through Wastewater Cultivation and Hydrothermal Conversion

The purpose of this study is to demonstrate feasibility of an integrated wastewater algae-to-biocrude process that can sustainably cultivate algal biomass for biofuel production. This process used pilot-scale algal cultivation ponds fed with municipal wastewater as the nutrient source. The open ponds were self-inoculated from the wastewater source, resulting in a mixed-culture microalgal community with distinct differences compared to laboratory-maintained and fertilized monocultures: 29.0% dry weight (dw) ash, 48.9% ash-free dry weight (afdw) carbon, 37.5% afdw oxygen, and 14.0% afdw lipid. The harvested algae was processed using hydrothermal liquefaction at 350 °C (autogenous pressures up to 2000 psig) for 1 h using 3 g of freeze-dried algae and 50 mL of water. The yield of biocrude was 44.5 ± 4.7% afdw, with an elemental weight percent composition of 78.7% carbon, 10.1% hydrogen, 4.4% nitrogen, and 5.5% oxygen and an energy content of 39 MJ/kg. Hydrothermal processing also resulted in the formation of ...

Oriented Nucleation of Diopside Crystals in Glass

Ceramic or glass-ceramic materials containing diopside attract a great deal of interest due to their potential use as bioactive materials. In this paper, the growth of diopside from the surface of a glass with the weight percent composition 54.96SiO2·18.4MgO·25.64CaO·1Al2O3 is described. EBSD-patterns were recorded from the surface and indexed as diopside. It was observed that the crystals were oriented with respect to the surface of the glass. The crystals grew in the form of asymmetrical pyramids which protrude from the surface by up to 0.3 μm. These pyramids contain at least four different orientations which share a common (100)-plane, indicating mechanical twinning. The crystal orientation of each twin changes during growth along the surface. Kinetic selection was observed during crystal growth into the bulk which does not occur in the form of solid crystal bodies. A glass skin covering the crystals was not detected.

TH‐A‐217BCD‐07: Validation of Breast Density Measurement Using Dual Energy Mammography: A Post Mortem Study

Purpose: To validate the use of dual energy mammography for the measurement of breast density in 40 post mortem ex vivo breast tissue samples. Methods: Twenty pairs of post mortem breast samples (n=40) were imaged with a full field digital mammography system. Low energy images were acquired at 28 kVp with a 50 μm rhodium filter at 60 mAs. High energy images were acquired at 49 kVp with a 300 μm copper filter at 30 mAs. Dual energy decomposition of the low and high energy images yielded individual pixel measurements of glandular and adipose equivalent material thicknesses. The decomposition was based on a previous calibration with glandular and adipose equivalent phantoms. Breast density (BD) was calculated as the ratio of glandular thickness over the sum total thickness. Each post mortem sample was then analyzed by chemical analysis based on desiccation, trituration and fat extraction to determine the weight and subsequent percent composition of water, lipid and lean (i.e. protein + mineral) contents. The fibroglandular ratio (FGR), a surrogate quantity to breast density, was calculated from the chemical analysis data as the ratio of the total volume of water and lean contents over the sum of all three contents. Results: Linear relationships between breast density and the water, lipid, and lean contents were all highly correlated. BD and FGR data were related by BD = 1.9 FGR ‐ 50 (r>0.99). Conclusions: The high correlation between breast composition data determined from images and data determined from chemical analysis serve to validate the use of dual energy mammography as a measurement technique. It is thought that more quantitative means of measuring breast density, like the one proposed here, will help to further enhance its use and utility as a marker and risk factor for the development of breast cancer.