bluuebunny/crossref_metadata_2025 huggingface dataset:
VGT and EGR Control of Common-Rail Diesel Engines Using an Artificial Neural Network
Authors: Oh Byounggul , Lee Minkwang , Park Yeongseop , Sohn Jeongwon , Won Jongseob , Sunwoo Myoungho
Published: November 2012

In diesel engines, variable geometry turbocharger (VGT) and exhaust gas recirculation (EGR) systems are used to increase engine specific power and reduce NOx emissions, respectively. Because the dynamics of both the VGT and EGR are highly nonlinear and coupled to each other, better performance may be attained by substituting nonlinear multiple input, multiple output (MIMO) controllers for the existing conventional lookup table-based linear controllers. This paper presents a coordinated VGT/EGR control system for common-rail direct injection diesel engines. The objective of the control system is to track target mass air flow and target intake manifold pressure by adjusting the EGR and VGT actuator positions. We designed a nonlinear MIMO control system using a neural control scheme that adopts an indirect adaptive control approach. The neural control system is comprised of a neural network identifier, which mimics the target air system, and a neural network controller, which calculates the actuator positions. The proposed control system has been validated with engine experiments under transient operating conditions. It was demonstrated from experimental results that the proposed control system shows improved target value tracking performance over conventional VGT/EGR control system.
Performance Measurements of a Unique Louver Particle Separator for Gas Turbine Engines
Authors: Musgrove Grant O. , Thole Karen A. , Grover Eric , Barker Joseph
Published: November 2012

Solid particles, such as sand, ingested into gas turbine engines, reduce the coolant flow in the turbine by blocking cooling channels in the secondary flow path. One method to remove solid particles from the secondary flow path is to use an inertial particle separator because of its ability to incur minimal pressure losses in high flow rate applications. In this paper, an inertial separator is presented that is made up of an array of louvers followed by a static collector. The performance of two inertial separator configurations was measured in a unique test facility. Performance measurements included pressure loss and collection efficiency for a range of Reynolds numbers and sand sizes. To complement the measurements, both two-dimensional and three-dimensional computational results are presented for comparison. Computational predictions of pressure loss agreed with measurements at high Reynolds numbers, whereas predictions of sand collection efficiency for a sand size range 0–200μm agreed within 10% of experimental measurements over the range of Reynolds numbers. Collection efficiency values were measured to be as high as 35%, and pressure loss measurements were equivalent to less than 1% pressure loss in an engine application.
A Feasibility Study of Vibration-Assisted Nano-Impact Machining by Loose Abrasives Using Atomic Force Microscope
Authors: James Sagil , Sundaram Murali M.
Published: November 2012

Nanomachining of brittle materials is required in a wide range of applications. This paper reports on the feasibility studies of vibration-assisted nano-impact machining by loose abrasives (VANILA), a novel nanomachining process for target-specific nanomachining of hard and brittle materials. A mathematical model based on Hertzian fracture mechanics theory has been developed to evaluate the feasibility of material removal in the VANILA process, where hard abrasive grains impact the brittle workpiece surface. Experimental investigations are conducted using a commercially available atomic force microscope (AFM), to validate the feasibility of the proposed process. Several nanocavities with circular shape, having depths ranging from 6 to 64 nm and diameters ranging from 78 to 276 nm, are successfully machined. Patterns of nanocavities are machined to confirm the repeatability and controllability of the process. Observation of tool tips using a scanning electron microscope (SEM) reveals that the tool wear in the VANILA process is lesser than that observed in indentation process.
From Chip to Cooling Tower Data Center Modeling: Chip Leakage Power and Its Impact on Cooling Infrastructure Energy Efficiency
Authors: Breen Thomas J. , Walsh Ed J. , Punch Jeff , Shah Amip J. , Bash Cullen E. , Kumari Niru , Cader Tahir
Published: November 2012

The power consumption of the chip package is known to vary with operating temperature, independently of the workload processing power. This variation is commonly known as chip leakage power, typically accounting for ~10% of total chip power consumption. The influence of operating temperature on leakage power consumption is a major concern for the information technology (IT) industry for design optimization where IT system power densities are steadily increasing and leakage power expected to account for up to ~50% of chip power in the near future associated with the reducing package size. Much attention has been placed on developing models of the chip leakage power as a function of package temperature, ranging from simple linear models to complex super-linear models. This knowledge is crucial for IT system designers to improve chip level energy efficiency and minimize heat dissipation. However, this work has been focused on the component level with little thought given to the impact of chip leakage power on entire data center efficiency. Studies on data center power consumption quote IT system heat dissipation as a constant value without accounting for the variance of chip power with operating temperature due to leakage power. Previous modeling techniques have also omitted this temperature dependent relationship. In this paper, we discuss the need for chip leakage power to be included in the analysis of holistic data center performance. A chip leakage power model is defined and its implementation into an existing multiscale data center energy model is discussed. Parametric studies are conducted over a range of system and environment operating conditions to evaluate the impact of varying degrees of chip leakage power. Possible strategies for mitigating the impact of leakage power are also illustrated in this study. This work illustrates that when including chip leakage power in the data center model, a compromise exists between increasing operating temperatures to improve cooling infrastructure efficiency and the increase in heat load at higher operating temperatures due to leakage power.
Real-time full-area monitoring of the filling process in molds for UV nanoimprint lithography using dark field illumination
Authors: Wang Qing , Hiroshima Hiroshi , Suzuki Kenta , Youn Sung-Won
Published: November 2012

A dark field illumination system has been developed for real-time full-area monitoring of resin filling in molds for use in ultraviolet nanoimprint lithography. The dark field illumination was successfully applied to monitor the filling process in molds with square patterns with dimensions 2 × 2 to 100 × 100 μm2. Real-time images of the full-area mold record the entire process of resin filling, starting from the time of mold contact, followed by resin being squeezed into the mold cavity and elimination of bubbles, to completion of the filling process. The disappearance of scattered light reflected from the bubbles trapped within the pattern cavities of the mold indicates the completion of the filling process. The accuracy of our method is verified using high magnification microscopy. Our proposed real-time full-area monitoring system provides a reliable method to monitor resin filling and enables in situ quality control of defects. This is an important and necessary requirement when employing nanoimprint lithography for the mass production of devices.
Lithographically fabricated gratings for the interferometric measurement of material shear moduli under extreme conditions
Authors: Gleason Arianna E. , Tiberio Richard C. , Mao Wendy L. , Ali Suzanne , Bolme Cynthia A. , Lazicki Amy , Bordonaro Garry , Treichler John , Genova Vincent , Eggert Jon H.
Published: November 2012

Electron beam lithography and photolithography were used to fabricate diffraction gratings on targets for laser-driven shock-wave experiments. This target design was used with an optical interferometric system to measure transverse wave motion of the target during dynamic (shock-wave) compression. A wedged-shaped diamond substrate and reflective grating on the sample's surface allowed detection of transverse motion. Proof of principle tests on single-crystal 〈100〉 Si samples gave a transverse wave speed of 5.9 km/s at 5 GPa and a shear modulus of 81 GPa. This experimental design has tremendous potential, including the possibility of measuring the shear properties of pure iron at Earth core conditions.
Selective laser ablation of radiation exposed methyl acetoxy calix(6)arene
Authors: Perera Pradeep N. , Schwartzberg Adam M. , de Oteyza Dimas G. , Dhuey Scott D. , Harteneck Bruce D. , Cabrini Stefano , Olynick Deirdre L.
Published: November 2012

The chemical mechanism of recently discovered high resolution laser dry development of methyl acetoxy calix(6)arene is probed. This process is an alternative to wet development and allows high aspect ratio patterns to be formed in resist without pattern collapse. Using infrared, Raman, and fluorescence spectroscopies, the authors have observed a reduction of the acetoxy groups, formation of hydroxyls and extended conjugation of the system due to the cross-linking under e-beam exposed film. These changes increase the laser absorption of the resist creating species that ablates under ambient conditions. Based on these studies, the authors surmise that chemical species formed during the e-beam exposure accelerate the ablation thus setting the basis for the selective ablation.
Talbot effect immersion lithography by self-imaging of very fine grating patterns
Authors: Sato Takashi
Published: November 2012

Talbot effect immersion lithography was investigated to improve resolution based on simulation results. The resolution limit of typical projection optics is determined by the wavelength λ of the light source and the numerical aperture. Alternatively, the Talbot effect forms self-images with no projection optics. For our simulations, the authors proposed using a mask with a Cr pattern illuminated by 193 nm ArF laser. The authors also assumed that the gap under the mask was filled with high-index immersion fluid of n = 1.64. The finite difference time domain (FDTD) optical simulation is shown for various pitches from 110 to 200 nm. So far, the distance of the self-imaging period has been estimated by second-order approximation, but the estimated result is found to differ significantly from the FDTD result. The periodic distance from low-order diffractive rays should be estimated by a higher-order approximation or an analytical method. Using Talbot effect immersion lithography, the one-dimensional line-and-space pattern of 60 nm pitch and the two-dimensional contact hole of 70 nm pitch can be transferred by a 193 nm light source.
Fast aerial image simulations for partially coherent systems by transmission cross coefficient decomposition with analytical kernels
Authors: Gong Peng , Liu Shiyuan , Lv Wen , Zhou Xinjiang
Published: November 2012

Aerial image simulation is one of the most critical components in the model-based optical proximity correction (OPC), which has become a necessary part of resolution enhancement techniques used to improve the performance of subwavelength optical lithography. In this paper, a fast aerial image simulation method is proposed for partially coherent systems by decomposing the transmission cross coefficient (TCC) into analytical kernels. The TCC matrix is projected onto a function space whose basis is analytical circle-sampling functions (CSFs) and converted into a much smaller projected matrix. By performing singular value decomposition (SVD) to the projected matrix, its eigenvectors together with the CSFs are used to generate a set of analytical TCC kernels. The proposed method avoids directly performing SVD to the large TCC matrix, making it much more runtime efficient than the conventional SVD method. Furthermore, the grid size of the kernels can be flexibly set to any desired value in aerial image simulations, which is not realizable with the conventional SVD method. The comparison of aerial image intensity errors and edge placement errors calculated by the proposed method and the conventional SVD method has confirmed the validity of the proposed method. An OPC example is also provided to further demonstrate its efficiency.
A real time dose monitoring and dose reconstruction tool for patient specific VMAT QA and delivery
Authors: Tyagi Neelam , Yang Kai , Gersten David , Yan Di
Published: November 2012

Purpose:

To develop a real time dose monitoring and dose reconstruction tool to identify and quantify sources of errors during patient specific volumetric modulated arc therapy (VMAT) delivery and quality assurance.

Methods:

The authors develop a VMAT delivery monitor tool called linac data monitor that connects to the linac in clinical mode and records, displays, and compares real time machine parameters with the planned parameters. A new measure, called integral error, keeps a running total of leaf overshoot and undershoot errors in each leaf pair, multiplied by leaf width, and the amount of time during which the error exists in monitor unit delivery. Another tool reconstructs Pinnacle3™ format delivered plan based on the saved machine logfile and recalculates actual delivered dose in patient anatomy. Delivery characteristics of various standard fractionation and stereotactic body radiation therapy (SBRT) VMAT plans delivered on Elekta Axesse and Synergy linacs were quantified.

Results:

The MLC and gantry errors for all the treatment sites were 0.00 ± 0.59 mm and 0.05 ± 0.31°, indicating a good MLC gain calibration. Standard fractionation plans had a larger gantry error than SBRT plans due to frequent dose rate changes. On average, the MLC errors were negligible but larger errors of up to 6 mm and 2.5° were seen when dose rate varied frequently. Large gantry errors occurred during the acceleration and deceleration process, and correlated well with MLC errors (r = 0.858, p = 0.0004). PTV mean, minimum, and maximum dose discrepancies were 0.87 ± 0.21%, 0.99 ± 0.59%, and 1.18 ± 0.52%, respectively. The organs at risk (OAR) doses were within 2.5%, except some OARs that showed up to 5.6% discrepancy in maximum dose. Real time displayed normalized total positive integral error (normalized to the total monitor units) correlated linearly with MLC (r = 0.9279, p < 0.001) and gantry errors (r = 0.742, p = 0.005). There is a strong correlation between total integral error and PTV mean (r = 0.683, p = 0.015), minimum (r = 0.6147, p = 0.033), and maximum dose (r = 0.6038, p = 0.0376).

Conclusions:

Errors may exist during complex VMAT planning and delivery. Linac data monitor is capable of detecting and quantifying mechanical and dosimetric errors at various stages of planning and delivery.
Localization of deformable tumors from short‐arc projections using Bayesian estimation
Authors: Hoegele W. , Zygmanski P. , Dobler B. , Kroiss M. , Koelbl O. , Loeschel R.
Published: November 2012

Purpose:

The authors present a stochastic framework for radiotherapy patient positioning directly utilizing radiographic projections. This framework is developed to be robust against anatomical nonrigid deformations and to cope with challenging imaging scenarios, involving only a few cone beam CT projections from short arcs.

Methods:

Specifically, a Bayesian estimator (BE) is explicitly derived for the given scanning geometry. This estimator is compared to reference methods such as chamfer matching (CM) and the minimization of the median absolute error adapted as tools of robust image processing and statistics. In order to show the performance of the stochastic short‐arc patient positioning method, a CIRS IMRT thorax phantom study is presented with movable markers and the utilization of an Elekta Synergy® XVI system. Furthermore, a clinical prostate CBCT scan of a Varian® On‐Board Imager® system is utilized to investigate the robustness of the method for large variations of image quality (anterior‐posterior vs lateral views).

Results:

The results show that the BE shifts reduce the initial setup error of up to 3 cm down to 3 mm at maximum for an imaging arc as short as 10° while CM achieves residual errors of 7 mm at maximum only for arcs longer than 40°. Furthermore, the BE can compensate robustly for low image qualities using several low quality projections simultaneously.

Conclusions:

In conclusion, an estimation method for marker‐based patient positioning for short imaging arcs is presented and shown to be robust and accurate for deformable anatomies.
Comprehensive assessment of the slice sensitivity profiles in breast tomosynthesis and breast CT
Authors: Nosratieh Anita , Yang Kai , Aminololama‐Shakeri Shadi , Boone John M.
Published: November 2012

Purpose:

This study experimentally evaluated the slice sensitivity profile (SSP) and its relationship between acquisition angle, object size, and cone angle. The sensitivity profile metric was used to characterize a breast tomosynthesis systemˈs resolution in the z‐axis. The SSP was also measured on a prototype breast computed tomography (bCT) system.

Methods:

The SSP was measured using brass disks placed within adipose tissue‐equivalent breast phantoms. The digital tomosynthesis system (Selenia Dimensions, Hologic Corporation, Bedford, MA) acquires projection images over a 15° angular range and the bCT scanner acquires projection images over a 360° angular range. Angular ranges between 15° and 360° were studied by using a subset of the projection images acquired on the bCT scanner. The SSP was determined by measuring a background‐corrected mean gray scale value as a function of the z‐position (axis normal to the plane of the detector).

Results:

The results show that SSP improves when the angular acquisition range is increased and the SSP approaches a delta function for angles greater than 180°. Smaller objects have a narrower SSP and the SSP is not significantly dependent on the cone angle. For a 2.5, 5, 10 mm disk, the full width at half maximum of the SSP was 35, 61, 115 mm, respectively, on the tomosynthesis system (at 15°) and was 0.5 mm for all disk diameters on the bCT scanner (at 360°).

Conclusions:

The SSP is dependent on object size and angular acquisition range. These dependencies are overcome once the angular acquisition range is increased beyond 180°.
Speed‐of‐sound compensated photoacoustic tomography for accurate imaging
Authors: Jose Jithin , Willemink Rene G. H. , Steenbergen Wiendelt , Slump C. H. , van Leeuwen Ton G. , Manohar Srirang
Published: November 2012

Purpose:

In most photoacoustic (PA) tomographic reconstructions, variations in speed‐of‐sound (SOS) of the subject are neglected under the assumption of acoustic homogeneity. Biological tissue with spatially heterogeneous SOS cannot be accurately reconstructed under this assumption. The authors present experimental and image reconstruction methods with which 2D SOS distributions can be accurately acquired and reconstructed, and with which the SOS map can be used subsequently to reconstruct highly accurate PA tomograms.

Methods:

The authors begin with a 2D iterative reconstruction approach in an ultrasound transmission tomography setting, which uses ray refracted paths instead of straight ray paths to recover accurate SOS images of the subject. Subsequently, they use the SOS distribution in a new 2D iterative PA reconstruction approach, where refraction of rays originating from PA sources is accounted for in accurately retrieving the distribution of these sources. Both the SOS reconstruction and SOS‐compensated PA reconstruction methods utilize the Eikonal equation to model acoustic wavefront propagation. The equation is solved using a high accuracy fast marching method.

Results:

The authors validated the new reconstruction algorithms using numerical phantoms. For experiments they utilized the recently introduced PER‐PACT method which can be used to simultaneously acquire SOS and PA data from subjects.

Conclusions:

It is first confirmed that it is important to take SOS inhomogeneities into account in high resolution PA tomography. The iterative reconstruction algorithms, that model acoustic refractive effects, in reconstructing SOS distributions, and subsequently using these distributions to correct PA tomograms, yield artifact‐free highly accurate images. The approach of using the hybrid measurement method and the new reconstruction algorithms is successful in substantially improving the quality of PA images with a minimization of blurring and artifacts.
Consensus recommendations for incident learning database structures in radiation oncology
Authors: Ford E. C. , Fong de Los Santos L. , Pawlicki T. , Sutlief S. , Dunscombe P.
Published: November 2012

Purpose:

Incident learning plays a key role in improving quality and safety in a wide range of industries and medical disciplines. However, implementing an effective incident learning system is complex, especially in radiation oncology. One current barrier is the lack of technical standards to guide users or developers. This report, the product of an initiative by the Work Group on Prevention of Errors in Radiation Oncology of the American Association of Physicists in Medicine, provides technical recommendations for the content and structure of incident learning databases in radiation oncology.

Methods:

A panel of experts was assembled and tasked with developing consensus recommendations in five key areas: definitions, process maps, severity scales, causality taxonomy, and data elements. Experts included representatives from all major North American radiation oncology organizations as well as users and developers of public and in‐house reporting systems with over two decades of collective experience. Recommendations were developed that take into account existing incident learning systems as well as the requirements of outside agencies.

Results:

Consensus recommendations are provided for the five major topic areas. In the process mapping task, 91 common steps were identified for external beam radiation therapy and 88 in brachytherapy. A novel feature of the process maps is the identification of “safety barriers,” also known as critical control points, which are any process steps whose primary function is to prevent errors or mistakes from occurring or propagating through the radiotherapy workflow. Other recommendations include a ten‐level medical severity scale designed to reflect the observed or estimated harm to a patient, a radiation oncology‐specific root causes table to facilitate and regularize root‐cause analyses, and recommendations for data elements and structures to aid in development of electronic databases. Also presented is a list of key functional requirements of any reporting system.

Conclusions:

Incident learning is recognized as an invaluable tool for improving the quality and safety of treatments. The consensus recommendations in this report are intended to facilitate the implementation of such systems within individual clinics as well as on broader national and international scales.
Dedicated breast CT: Fibroglandular volume measurements in a diagnostic population
Authors: Vedantham Srinivasan , Shi Linxi , Karellas Andrew , O'Connell Avice M.
Published: November 2012

Purpose:

To determine the mean and range of volumetric glandular fraction (VGF) of the breast in a diagnostic population using a high‐resolution flat‐panel cone‐beam dedicated breast CT system. This information is important for Monte Carlo‐based estimation of normalized glandular dose coefficients and for investigating the dependence of VGF on breast dimensions, race, and pathology.

Methods:

Image data from a clinical trial investigating the role of dedicated breast CT that enrolled 150 women were retrospectively analyzed to determine the VGF. The study was conducted in adherence to a protocol approved by the institutional human subjects review boards and written informed consent was obtained from all study participants. All participants in the study were assigned BI‐RADS® 4 or 5 as per the American College of Radiology assessment categories after standard diagnostic work‐up and underwent dedicated breast CT exam prior to biopsy. A Gaussian‐kernel based fuzzy c‐means algorithm was used to partition the breast CT images into adipose and fibroglandular tissue after segmenting the skin. Upon determination of the accuracy of the algorithm with a phantom, it was applied to 137 breast CT volumes from 136 women. VGF was determined for each breast and the mean and range were determined. Pathology results with classification as benign, malignant, and hyperplasia were available for 132 women, and were used to investigate if the distributions of VGF varied with pathology.

Results:

The algorithm was accurate to within ±1.9% in determining the volume of an irregular shaped phantom. The study mean (± inter‐breast SD) for the VGF was 0.172 ± 0.142 (range: 0.012–0.719). VGF was found to be negatively correlated with age, breast dimensions (chest‐wall to nipple length, pectoralis to nipple length, and effective diameter at chest‐wall), and total breast volume, and positively correlated with fibroglandular volume. Based on pathology, pairwise statistical analysis (Mann‐Whitney test) indicated that at the 0.05 significance level, there was no significant difference in distributions of VGF without adjustment for age between malignant and nonmalignant breasts (p = 0.41). Pairwise comparisons of the distributions of VGF in increasing order of mammographic breast density indicated all comparisons were statistically significant (p < 0.002).

Conclusions:

This study used a different clinical prototype breast CT system than that in previous studies to image subjects from a different geographical region, and used a different algorithm for analysis of image data. The mean VGF estimated from this study is within the range reported in previous studies, indicating that the choice of 50% glandular weight fraction to represent an average breast for Monte Carlo‐based estimation of normalized glandular dose coefficients in mammography needs revising. In the study, the distributions of VGF did not differ significantly with pathology.
Organ sample generator for expected treatment dose construction and adaptive inverse planning optimization
Authors: Nie Xiaobo , Liang Jian , Yan Di
Published: November 2012

Purpose:

To create an organ sample generator (OSG) for expected treatment dose construction and adaptive inverse planning optimization. The OSG generates random samples of organs of interest from a distribution obeying the patient specific organ variation probability density function (PDF) during the course of adaptive radiotherapy.

Methods:

Principle component analysis (PCA) and a time‐varying least‐squares regression (LSR) method were used on patient specific geometric variations of organs of interest manifested on multiple daily volumetric images obtained during the treatment course. The construction of the OSG includes the determination of eigenvectors of the organ variation using PCA, and the determination of the corresponding coefficients using time‐varying LSR. The coefficients can be either random variables or random functions of the elapsed treatment days depending on the characteristics of organ variation as a stationary or a nonstationary random process. The LSR method with time‐varying weighting parameters was applied to the precollected daily volumetric images to determine the function form of the coefficients. Eleven h&n cancer patients with 30 daily cone beam CT images each were included in the evaluation of the OSG. The evaluation was performed using a total of 18 organs of interest, including 15 organs at risk and 3 targets.

Results:

Geometric variations of organs of interest during h&n cancer radiotherapy can be represented using the first 3 ∼ 4 eigenvectors. These eigenvectors were variable during treatment, and need to be updated using new daily images obtained during the treatment course. The OSG generates random samples of organs of interest from the estimated organ variation PDF of the individual. The accuracy of the estimated PDF can be improved recursively using extra daily image feedback during the treatment course. The average deviations in the estimation of the mean and standard deviation of the organ variation PDF for h&n cancer radiotherapy were less than 2 and 1 mm, respectively, for most organs after the second week of treatment. After the first three weeks of treatment, the mean discrepancy of the dose estimation accuracy was within 1% for most of organs, the corresponding standard deviation was within 2.5% for parotids, the brain stem and the cochleae, and within 1% for other organs.

Conclusions:

A patient specific OSG is feasible and can be used to generate random samples of organs of interest for the expected treatment dose construction and adaptive inverse planning. The accuracy of the OSG can be improved continuously and recursively during the adaptive treatment course using daily volumetric image feedback.
Chirp resonance spectroscopy of single lipid-coated microbubbles using an “acoustical camera”
Authors: Renaud G. , Bosch J. G. , van der Steen A. F. W. , de Jong N.
Published: November 2012

An acoustical method was developed to study the resonance of single lipid-coated microbubbles. The response of 127 SonoVue microbubbles to a swept sine excitation between 0.5 and 5.5 MHz with a peak acoustic pressure amplitude of 70 kPa was measured by means of a 25 MHz probing wave. The relative amplitude modulation in the signal scattered in response to the probing wave is approximately equal to the radial strain induced by the swept sine excitation. An average damping coefficient of 0.33 and an average resonance frequency of 2.5 MHz were measured. Microbubbles experienced an average peak radial strain of 20%.
Influence of cortical endplate on speed of sound in bovine femoral trabecular bone in vitro
Authors: Hwang Kyo Seung , Lee Kang Il
Published: November 2012

Speed of sound (SOS) was measured in 14 bovine femoral trabecular bone samples with and without the cortical endplates with various thicknesses of 1.00, 1.31, 1.47, 1.75, and 2.00 mm. The presence of the cortical endplates resulted in an increase in the mean SOS of 16 m/s (+0.9%) to 91 m/s (+5.3%). The mean SOS measured in the samples with and without the cortical endplates exhibited similar significant correlations with apparent bone density (r = 0.86–0.91). All the SOS measurements were also found to be highly correlated with each other (r = 0.89–0.99).
Quantifying the effect of fuel reduction treatments on fire behavior in boreal forests
Authors: Butler B.W. , Ottmar R.D. , Rupp T.S. , Jandt R. , Miller E. , Howard K. , Schmoll R. , Theisen S. , Vihnanek R.E. , Jimenez D.
Published: November 2012

Mechanical (e.g., shearblading) and manual (e.g., thinning) fuel treatments have become the preferred strategy of many fire managers and agencies for reducing fire hazard in boreal forests. This study attempts to characterize the effectiveness of four fuel treatments through direct measurement of fire intensity and forest floor consumption during a single prescribed burn. The treatments included (1) thinning trees and removing debris (THIN-REMOVE-1 and -2), (2) thinning trees and burning the debris onsite, (3) shearblading and leaving the debris in place (SHEAR), and (4) shearblading and piling the debris in windrows (SHEAR-ROW). Fire burned through treatments 1, 3, and 4 and one control unit. The highest fire intensities (maximum temperature of 1150 °C, maximum heat flux of 227 kW·m–2, and fire cumulative energy release of 4277 J·m–2) were measured in the control. Treatment 1 exhibited a peak temperature of 267 °C, peak heating of 16 kW·m–2, and cumulative energy release of 2600 J·m–2. Treatments 3 and 4 exhibited peak temperatures of 170 and 66 °C, peak heating of 51 and 3 kW·m–2, and cumulative energy release of 2500 and 1800 J·m–2, respectively. The thinned treatment showed the most significant impact in the context of reduced heat release.
Legionellaand non-Legionellabacteria in a biological treatment plant
Authors: Fykse Else Marie , Aarskaug Tone , Thrane Ingjerd , Blatny Janet Martha
Published: November 2012

Legionella pneumophila were previously identified in the aeration ponds (up to 1010CFU/L) of a biological wastewater treatment plant at Borregaard Ind. Ltd., Sarpsborg, Norway, and in air samples (up to 3300 CFU/m3) collected above the aeration ponds. After 3 outbreaks of Legionnaires’ disease reported in this area in 2005 and 2008, the aeration ponds of the plant were shut down by the Norwegian authorities in September 2008. The aim of the present work was to analyze the Legionella and non-Legionella bacterial communities in the aeration ponds before and during the shutdown process and to identify potential human pathogens. The non-Legionella bacterial community was investigated in selected samples during the shutdown process by 16S rDNA sequencing of clone libraries (400 clones) and growth analysis. The concentration of L. pneumophila and Pseudomonas spp. DNA were monitored by quantitative PCR. Results showed a decrease in the concentration of L. pneumophila and Pseudomonas spp. during the shutdown. This was accompanied by a significant change in the composition of the bacterial community in the aeration ponds. This study demonstrated that several advanced analytical methods are necessary to characterize the bacterial population in complex environments, such as the industrial aeration ponds.
An interacting two-fluid scenario for dark energy in anisotropic cosmological model
Authors: Singh T. , Chaubey R.
Published: November 2012

The open anisotropic cosmological model of the early Universe is considered. We study the evolution of the dark energy parameter within anisotropic Bianchi type-V cosmological model filled with barotropic fluid and dark energy. The solutions have been obtained for power law and exponential forms of the expansion parameter. (They correspond to constant deceleration parameter in general relativity.) For large time (i.e., t → ∞), the models tend asymptotically to an isotropic Friedmann–Robertson–Walker cosmological model under certain conditions.
Barriers to nutritional intake in patients with acute hip fracture: time to treat malnutrition as a disease and food as a medicine?
Authors: Bell Jack , Bauer Judith , Capra Sandra , Pulle Chrys Ranjeev
Published: November 2012

Inadequate energy and protein intake leads to malnutrition; a clinical disease not without consequence post acute hip fracture. Data detailing malnutrition prevalence, incidence, and intake adequacy varies widely in this patient population. The limited success of reported interventional strategies may result from poorly defined diagnostic criteria, failure to address root causes of inadequate intake, or errors associated with selection bias. This pragmatic study used a sequential, explanatory mixed methods design to identify malnutrition aetiology, prevalence, incidence, intake adequacy, and barriers to intake in a representative sample of 44 acute hip fracture patients (73% female; mean age, 81.7 ± 10.8 years). On admission, malnutrition prevalence was 52.2%. Energy and protein requirements were only met twice in 58 weighed 24 h food records. Mean daily patient energy intake was 2957 kJ (50.9 ± 36.1 kJ·kg–1) and mean protein intake was 22.8 g (0.6 ± 0.46 g·kg–1). This contributed to a further in-patient malnutrition incidence of 11%. Barriers to intake included patient perceptions that malnutrition and (or) inadequate intake were not a problem, as well as patient and clinician perceptions that treatment for malnutrition was not a priority. Malnutrition needs to be treated as a disease not without consequence, and food should be considered as a medicine after acute hip fracture.
Properties of stumps that promote the growth and survival of Japanese cedar saplings in a natural old-growth forest
Authors: Ota Takayuki , Masaki Takashi , Sugita Hisashi , Kanazashi Tatsuo , Abe Hisashi
Published: November 2012

In a natural forest that has experienced logging and lacks large fallen logs, cut stumps are expected to become a suitable substrate for regeneration. We investigated the properties of stumps that promoted the natural regeneration of coniferous species in a natural old-growth forest dominated by Cryptomeria japonica (L.f.) D. Don. A comparison of C. japonica saplings growing in three microsites (ground, stumps, and fallen logs) revealed that sapling density was highest on the stumps; 75% of saplings were distributed on stumps, which occupied only 3% of the projected forest area. The mortality of saplings during the 3-year study period did not differ significantly among the three microsites. Six properties of stumps were quantified: height, diameter at ground level, decay class, species taxon, type (i.e., cause of occurrence: logging or natural disturbance), and light conditions. Of these properties, the type of stump was the most influential. The density of saplings was significantly greater on stumps produced by logging than on naturally broken stumps. Taller stumps exhibited a significantly higher density of saplings; indeed, there were no saplings on stumps less than 60 cm in height. Saplings on stumps were concentrated in higher positions on the stump, and survivorship tended to be greater when their root location was higher. We concluded that the height of the microsite was an important factor for regeneration of C. japonica at this research site, where saplings were under competition with dense undergrowth vegetation. Most of the fallen logs were less than 60 cm in height and it appeared unlikely that they would function as regeneration sites for C. japonica.
The effect of size and competition on tree growth rate in old-growth coniferous forests
Authors: Das Adrian
Published: November 2012

Tree growth and competition play central roles in forest dynamics. Yet models of competition often neglect important variation in species-specific responses. Furthermore, functions used to model changes in growth rate with size do not always allow for potential complexity. Using a large data set from old-growth forests in California, models were parameterized relating growth rate to tree size and competition for four common species. Several functions relating growth rate to size were tested. Competition models included parameters for tree size, competitor size, and competitor distance. Competitive strength was allowed to vary by species. The best ranked models (using Akaike’s information criterion) explained between 18% and 40% of the variance in growth rate, with each species showing a strong response to competition. Models indicated that relationships between competition and growth varied substantially among species. The results also suggested that the relationship between growth rate and tree size can be complex and that how we model it can affect not only our ability to detect that complexity but also whether we obtain misleading results. In this case, for three of four species, the best model captured an apparent and unexpected decline in potential growth rate for the smallest trees in the data set.
Total belowground carbon and nitrogen partitioning of mature black spruce displaying genetic × soil moisture interaction in growth
Authors: Major John E. , Johnsen Kurt H. , Barsi Debby C. , Campbell Moira
Published: November 2012

Total belowground biomass, soil C, and N mass were measured in plots of 32-year-old black spruce ( Picea mariana (Mill.) Britton, Sterns & Poggenb.) from four full-sib families studied previously for drought tolerance and differential productivity on a dry and a wet site. Stump root biomass was greater on the wet than on the dry site; however, combined fine and coarse root biomass was greater on the dry than on the wet site, resulting in no site root biomass differences. There were no site differences in root distribution by soil depth. Drought-tolerant families had greater stump root biomass and allocated relatively less to combined coarse and fine roots than drought-intolerant families. Fine roots (<2 mm) made up 10.9% and 50.2% of the belowground C and N biomass. Through 50 cm soil depth, mean total belowground C mass was 187.2 Mg·ha–1, of which 8.9%, 3.4%, 0.7%, and 87.0% were from the stump root, combined fine and coarse roots, necromass, and soil, respectively. Here, we show that belowground C sequestration generally mirrors (mostly from stump roots) aboveground growth, and thus, trends in genetic and genetic × environment productivity effects result in similar effects on belowground C sequestration. Thus, tree improvement may well be an important avenue to help stem increases in atmospheric CO2.
Endurance exercise in a rat model of metabolic syndrome
Authors: Cameron Isabelle , Alam Mohammad Ashraful , Wang Jianxiong , Brown Lindsay
Published: November 2012

We have measured the responses to endurance exercise training on body composition and glucose regulation, as well as cardiovascular and liver structure and function in rats fed a high carbohydrate and high fat (HCHF) diet as a model of human metabolic syndrome. Male Wistar rats (9–10 weeks old) were randomly allocated into corn starch (CS) or HCHF diet groups for 16 weeks; half of each group were exercised on a treadmill for 20, 25, and then 30 min/day, 5 days/week, during the last 8 weeks of the protocol. Metabolic, cardiovascular, and liver parameters were monitored. The HCHF diet induced symptoms of metabolic syndrome, including obesity, dyslipidemia, impaired glucose tolerance, and increased systolic blood pressure associated with the development of cardiovascular remodeling and nonalcoholic steatohepatitis. Exercise in HCHF rats decreased body mass, abdominal fat pads and circumference, blood glucose concentrations, plasma lipid profiles, systolic blood pressure, left ventricular diastolic stiffness, collagen deposition and inflammatory cell infiltration in the left ventricle, improved aortic contractile and relaxation responses, and decreased liver mass and hepatic fat accumulation. This study demonstrates that endurance exercise is effective in this rat model of diet-induced metabolic syndrome in improving body composition and glucose regulation, as well as cardiovascular and liver structure and function.
Differences between femoral artery and vein smooth muscle cells in volume-regulated chloride channels
Authors: Kang Xiao-Long , Zhang Min , Liu Jie , Lv Xiao-Fei , Tang Yong-Bo , Guan Yong-Yuan
Published: November 2012

The purpose of the present study was to compare the differences between the role of volume-regulated Cl– channels (VRCCs) in veins and arteries. We used the whole cell patch clamp and fluorescence imaging techniques to evaluate swelling-induced Cl– current (ICl,vol) and changes in the intracellular concentrations of Cl– ([Cl–]i) induced by hypotonic solutions in rat femoral artery cells (FASMCs) and vein smooth muscle cells (FVSMCs). ICl,vol and [Cl–]i decline induced by hypotonic solution were more prominent in FASMCs than in FVSMCs. ICl,vol and the alterations in [Cl–]i were gradually increased as the number of cell passages increased. However, the regulatory function of tyrosine protein phosphorylation in volume-regulated chloride movement is prominent in veins. The expression of ClC-3 was higher in FASMCs than in FVSMCs. VRCC activity is more pronounced in rat femoral arteries than in veins. VRCC activity and tyrosine protein phosphorylation regulative function increase gradually as vascular cells switch from contractile to proliferative phenotypes.
ON NON-PRIMITIVE PALINDROMIC CONTEXT-FREE LANGUAGES
Authors: FAZEKAS SZILÁRD ZSOLT , LEUPOLD PETER , SHIKISHIMA-TSUJI KAYOKO
Published: November 2012

This work continues investigations on avoidability of languages. We show that the language of primitive non-palindromes is strongly unavoidable for context-free languages that are not linear. This means that every language from this class contains infinitely many primitive non-palindromes.

In the second part, we extend the defintion of palindromes. In the center of a word we admit a bounded factor that is not palindromic. For k-palindromes, the length of this factor can be up to k. For non-primitive words, k-palindromicity implies conventional palindromicity if these words are long enough. Therefore we can extend the unavoidability result to k-palindromes.
TESTING FOR FORBIDDEN POSETS IN ORDERED ROOTED FORESTS
Authors: YAHALOM ORLY
Published: November 2012

We initiate the study of testing for general forbidden posets in a colored ordered rooted forest whose structure is fixed. First, we consider the case where the forbidden set consists of (ancestral) chains, and second, we consider the case in which it consists of one general ordered rooted forest. For both cases, we provide 1-sided error, non-adaptive tests, whose query complexity is polynomial in ∊-1 and is independent of the input size and the number of colors. Both tests do not require additional time complexity beyond the complexity of making the queries, except an O(n) time preprocessing stage in the test for a set of chains.
ON THE CONCEPTS OF VACUUM AND MASS AND THE SEARCH FOR HIGGS
Authors: OKUN L. B.
Published: November 2012

This review gives some recollections on the recent history of the concepts of vacuum and mass and the search for higgs. According to the widely spread terminology, the Higgs field permeates vacuum and serves as the origin of masses of all fundamental particles including the Higgs boson — the higgs.
ELECTRONIC STRUCTURES AND OPTICAL PROPERTIES OF 2Al- and 2Ca-DOPED β-Si3N4: A FIRST-PRINCIPLES STUDY
Authors: LU XUEFENG , LA PEIQING , GUO XIN , WEI YUPENG , NAN XUELI , HE LING
Published: November 2012

First-principles calculations have been conducted to study the electronic structures and optical properties of 2 Al - and 2 Ca -doped β- Si 3 N 4. Calculated formation energies of 2 Al - and 2 Ca -doped systems are 5.9745 eV and 18.9376 eV, respectively, indicating the former has a stable structure than the latter. The band gaps of two systems are 3.1573 eV and 2.0155 eV, respectively, reveals that the band structures of them behave like semiconductors. The static dielectric constants of two systems are 40 and 37, respectively, which denotes their potential applications in electronics and optics. The strong absorption bands ranging from 4 eV to 16 eV become much sharper and show a red-shift after doping. The offset of 2Al -doped system is larger than that of 2Ca -doped system. The absorption coefficient can be remarkably modulated by doping. In calculated frequency-dependent electron energy loss spectra (EELS) of doping systems, the host peaks all locate at about 15 eV.
QUANTUM CAPACITANCE EFFECT ON ZIG-ZAG GRAPHENE NANOSCROLLS (ZGNS) (16, 0)
Authors: HAMZAH AFIQ , AHMADI M. T. , ISMAIL RAZALI
Published: November 2012

Miniaturization of electronic devices carries them to the quantum limits which mean quantum effect will be dominant in nano-size device characterization. A first band analytical model of the quantum capacitance for (16, 0) zig-zag graphene nanoscroll (ZGNS) is presented. The behavior of the quantum capacitance within the degeneracy limits is approximated using the Maxwell–Boltzmann approximation within a range of E - EF > 3KBT. The quantum capacitance is subsequently derived from the carrier density of the ZGNS due to its significance within one-dimensional (1D) devices by employing the Taylor's series expansion for parabolic energy band structure approximation. Additionally, the quantum capacitance analytical derivation in term of ZGNS physical form considering the Archimedean spiral-type structure is modeled. Because of its unique geometry structure which provides high area for intercalation, it is expected that ZGNS structure (length and interlayer distances) will alter the quantum capacitance. We also report that at first sub-band of (16, 0) ZGNS the quantum capacitance reach degenerate limit at approximately of ≅ 0.49 × 10-10 F/m @ 49 pF/m .