bluuebunny/crossref_metadata_2025 huggingface dataset:
Response Surface Mapping of Performance for Helical Groove Seals With Incompressible Flow
Authors: Watson Cori , Untaroiu Alexandrina , Wood Houston G. , Weaver Brian K. , Morgan Neal , Jin Hanxiang
Published: September 2016

Helical groove seals are commonly used in multistage pumps. These seals have continuously cut grooves, like a screw, into the surface of the stator. The effects of design parameters on the performance of these seals — both in terms of leakage and rotordynamic coefficients — are not well understood, therefore the goal of this study is to characterize that performance for a wide range of designs. The design variables of interest in this study are groove width, groove depth, groove helix angle, density of the fluid, and the number of continuously cut grooves around the seal. The spacing between the grooves is predetermined by the number of grooves and groove helix angle. The fluid is assumed to have a constant density. The helix angle is 0 degrees for circumferential grooves, between 0 and 90 degrees for grooves pumping towards the inlet, 90 degrees for axial grooves, and between 90 and 180 degrees for grooves pumping towards the outlet. A large number of levels of helix angles were selected to represent the variety of angles possible and the two pumping directions. Helical groove seals with grooves pumping towards the outlet have been shown to produce much higher leakage and decreased stability. For each seal design in the sample space, a bulk flow method was used to calculate the performance. The selection of designs in the sample space was derived using a design of experiments approach. Because of the computational efficiency of the bulk flow code, more than 360 designs were simulated. The response surfaces for leakage, effective damping and effective stiffness — measures of instability often called the instability coefficient — were plotted versus pairs of design parameters to show graphically the effect of changing design parameters on seal performance. Baseline designs for seals pumping towards the inlet and seals pumping towards the outlet were also analyzed in a full 360 degree model with ANSYS CFX. The agreement of the 3D computational fluid dynamics simulation in ANSYS with the bulk flow code verified the accuracy of the bulk flow response surfaces. Finally, a multifactor least-squares linear regression was used to derive a relationship between the design parameters selected and the leakage as well as effective damping and effective stiffness. These equations allow the user to predict the leakage and rotordynamic properties based on values of the design parameters. The results of this study are to be able to predict the leakage and rotordynamic system behavior of future designs and provide insight into the physical mechanisms of helical groove seals.
Numerical Study on Flow and Heat Transfer of a Cooled First Stage Vane of a Gas Turbine
Authors: Ye Lv , Liu Zhao , Wang Xiangyu , Feng Zhenping
Published: September 2016

This paper presents a numerical simulation of composite cooling on a first stage vane of a gas turbine, in which gas by fixed composition mixture is adopted. To investigate the flow and heat transfer characteristics, two internal chambers which contain multiple arrays of impingement holes are arranged in the vane, several arrays of pin-fins are arranged in the trailing edge region, and a few arrays of film cooling holes are arranged on the vane surfaces to form the cooling film. The coolant enters through the shroud inlet, and then divided into two parts. One part is transferred into the chamber in the leading edge region, and then after impinging on the target surfaces, it proceeds further to go through the film cooling holes distributed on the vane surface, while the other part enters into the second chamber immediately and then exits to the mainstream in two ways to effectively cool the other sections of the vane. In this study, five different coolant flow rates and six different inlet pressure ratios were investigated. All the cases were performed with the same domain grids and same boundary conditions.

It can be concluded that for the internal surfaces, the heat transfer coefficient changes gradually with the coolant flow rate and the inlet total pressure ratio, while for the external surfaces, the average cooling effectiveness increases with the increase of coolant mass flow rates while decreases with the increase of the inlet stagnation pressure ratios within the study range.
Experimentally Measured Effects of Incidence Angle on the Adiabatic and Overall Effectiveness of a Fully Cooled Turbine Airfoil With Showerhead Shaped Holes
Authors: Chavez Kyle , Slavens Thomas N. , Bogard David
Published: September 2016

Manufacturing and assembly variation can lead to shifts in the inlet flow incidence angles of a rotating turbine airfoil row. Understanding the sensitivity of the adiabatic film cooling effectiveness to a range of inlet conditions is necessary to verifying the robustness of a cooling design. In order to investigate the effects of inlet flow incidence angles, adiabatic and overall effectiveness data were measured in a low speed linear cascade at 0° and 10° of the designed operating condition. Tests were completed at an inlet Reynolds number of Re=120000 and a turbulence intensity of Tu = 5% at the leading edge of the test article. Particle Image Velocimetry was used to verify the incident flow angle for each angle studied. The test section was first adjusted so that the pressure distribution and stagnation line of the airfoil matched those predicted by an aerodynamic CFD model. IR thermography was then used to measure the adiabatic effectiveness levels of the fully-cooled airfoil model with nine rows of shaped holes of varying construction and feed delivery. Measurements were taken over a range of blowing ratios and at a density ratio of DR=1.23. This process was repeated for the two incidence angles measured, while the inlet pressure to the airfoil model was held constant for these incidence angle changes. Differences in laterally adiabatic effectiveness across the airfoil model were most evident in the showerhead, with changes as large as 0.2. The effect persisted most strongly at s/D=±35 downstream of the stagnation row of holes, but was visible over the whole viewable area of 160 s/D. The effect was due to the stagnation line affecting the film at the showerhead row. Due to this effect, the showerhead was investigated in detail, including effects of the stagnation line shift as well as the influence of the incidence angle on the overall effectiveness of the showerhead region. It was found that the stagnation line has the tendency to dramatically increase the near-hole adiabatic effectiveness levels when positioned within the breakout footprint of the hole. The effect persisted for the overall effectiveness study, since the hole spacing for this particular configuration was wide enough that the through hole convection was not completely dominant. This is the first study to present measured effectiveness values over both the pressure- and suction-side surfaces of a fully-cooled airfoil for appreciably off-nominal incidence angles as well as examine adiabatic and overall effectiveness levels for a conical stagnation row of holes.
Experimental Investigation of Fluid Structure Interaction of Impeller Like Disks in Super Critical Carbon Dioxide
Authors: Pereboom H. P. , van Beek P. J. G. , Smeulers J. P. M.
Published: September 2016

In radial compressors working with high density gases, such as super critical carbon dioxide, strong interactions between the fluid and the impeller can cause large dynamic loads that can lead to damage or even failure. Acoustic resonances in the compressor cavities couple strongly with the vibration modes of the impeller.

The coupled acoustic-structural modes can be predicted by means of complex models that need to be validated. To this end a test rig has been developed in which impeller like structures can be tested under high density gas conditions. In this paper the experimental setup is described with which the required data for the validation of the models is generated. The focus of this paper is not on data analysis and comparisons with models since this is part of two separate PhD projects. To demonstrate the relevance of the results a short preliminary comparison with finite element modeling is made.

The present test rig has been operated with (super critical) carbon dioxide in a pressure range from atmospheric pressure to 200 bar and temperatures between 40 and 60 degrees C.

Two types of simplified impellers have been tested: a single disk and a double disk with ribs. The latter mimics the shape of an impeller. The diameter of the impeller disk is comparable to a real impeller. The disks are mounted in a housing that represents the compressor stator including a diffuser. The housing is placed inside a specially designed pressure vessel. Several parameters can be varied, such as the width of the cavities, the clearance between the impeller and the diffuser, etc. In the test set up multiple pressure transducers are installed to measure the acoustic modes. To identify the modal deformation of the impeller, glass fiber sensors (so-called FBG’s) have been installed at 38 of points on the impeller. The transfer functions from fluid to structure are measured by means of acoustic excitation. Vice versa the transfer function from structure to fluid is measured by means of impulse excitation of the disk. In this paper the test rig is described and preliminary results are presented.
Micromechanics-Based Fracture Risk Assessment Using Integrated Probabilistic Damage Tolerance Analysis and Manufacturing Process Models
Authors: Enright Michael P. , McClung R. Craig , Chan Kwai S. , McFarland John , Moody Jonathan P. , Sobotka James C.
Published: September 2016

Materials engineering and damage tolerance assessment have traditionally been performed as disjoint processes involving repeated tests that can ultimately prolong the time required for certification of new materials. Computational advances have been made both in the prediction of material properties and probabilistic damage tolerance analysis, but have been pursued primarily as independent efforts. Integrated computational materials engineering (ICME) has the potential to significantly reduce the time required for development and insertion of new materials in the gas turbine industry. A manufacturing process software tool called DEFORM™ has been linked with a probabilistic damage tolerance analysis (PDTA) software tool called DARWIN® to form a new capability for ICME of gas turbine engine components. DEFORM simulates rotor manufacturing processes including forging, heat treating, and machining to compute residual stress and strain, track anomaly location, and predict microstructure including grain size and orientation. DARWIN integrates finite element stress analysis results, fracture mechanics models, material anomaly data, probability of anomaly detection, and inspection schedules to compute the probability of fracture of a gas turbine engine rotor as a function of operating cycles. Previous papers have focused on probabilistic modeling of residual stresses in DARWIN based on manufacturing process training data from DEFORM. This paper describes recent efforts to extend the probabilistic link between DEFORM and DARWIN to enable modeling of residual strain, average grain size, and ALA (unrecrystalized) grain size as random variables. Gaussian Process modeling is used to estimate the relationship among model responses and material processing parameters. These random variables are applied to microstructure-based fatigue crack nucleation and growth models for use in probabilistic risk assessments. The integrated DARWIN-DEFORM capability is demonstrated for a representative engine disk model which illustrates the influences of manufacturing-induced random variables on component fracture risk. The results provide critical insight regarding the potential benefits of integrating probabilistic computational material processing models with probabilistic damage tolerance-based risk assessment.
Scaling Roughness Effects on Pressure Loss and Heat Transfer of Additively Manufactured Channels
Authors: Stimpson Curtis K. , Snyder Jacob C. , Thole Karen A. , Mongillo Dominic
Published: September 2016

Additive manufacturing (AM) with metal powder has made possible the fabrication of gas turbine components with small and complex flow paths that cannot be achieved with any other manufacturing technology presently available. The increased design space of AM allows turbine designers to develop advanced cooling schemes in high temperature components to increase cooling efficiency. Inherent in AM with metals is the large surface roughness that cannot be removed from small internal geometries. Such roughness has been shown in previous studies to significantly augment pressure loss and heat transfer of small channels. However, the roughness on these channels or other surfaces made from AM with metal powder has not been thoroughly characterized for scaling pressure loss and heat transfer data. This study examines the roughness of the surfaces of channels of various hydraulic length scales made with direct metal laser sintering (DMLS). Statistical roughness parameters are presented along with other parameters that others have found to correlate with flow and heat transfer. The pressure loss and heat transfer previously reported for the DMLS channels studied in this work are compared to the physical roughness measurements. Results show that the relative arithmetic mean roughness correlates well with the relative equivalent sand grain roughness. A correlation is presented to predict the Nusselt number of flow through AM channels which gives better predictions of heat transfer than correlations currently available.
Supercritical CO2 Radial Turbine Design Performance as a Function of Turbine Size Parameters
Authors: Qi Jianhui , Reddell Thomas , Qin Kan , Hooman Kamel , Jahn Ingo H. J.
Published: September 2016

Supercritical CO2 (sCO2) radial inflow turbine are an enabling technology for small scale concentrated solar thermal power. They are a research direction of the Australian Solar Thermal Research Initiative (ASTRI). This study uses the 1D meanline design code TOPGEN, to explore the radial turbine design space under consideration of sCO2 real gas properties. TOPGEN maps a parametric design space defined by flow and head coefficient.

The preliminary design code is used explore the feasibility, geometry and performance of sCO2 turbines in the 100kW to 200kW range in order to assess feasible design spaces and to investigate turbine scaling. Turbines are scaled with respect to power, while maintaining specific speed constant and with respect to speed. This analysis shows that both scaling approaches change the feasible design space and that both geometric constraints such as blade height or operational constraints such as blade natural frequency can significantly limit the design space.

Detailed analysis of four shortlisted designs shows that turbine efficiencies close to 85% can be attained for 100kW and 200kW output powers, even when operating at reduced rotor speeds. This work provides new insight towards the design of small scale radial turbines for operation with sCO2 and highlights scaling issues that may arise when testing sub-scale turbine prototypes.
Classification of breast lesions using segmented quantitative ultrasound maps of homodyned K distribution parameters
Authors: Byra Michał , Nowicki Andrzej , Wróblewska‐Piotrzkowska Hanna , Dobruch‐Sobczak Katarzyna
Published: September 2016

Purpose

Statistical modeling of an ultrasound backscattered echo envelope is used for tissue characterization. However, in the presence of complex structures within the analyzed area, estimation of parameters is disturbed and unreliable, e.g., in the case of breast tumor classification. In order to improve the differentiation of breast lesions, the authors proposed a method based on the segmentation of homodyned K distribution parameter maps. Regions within lesions of different scattering properties were extracted and analyzed. In order to improve the classification, the best‐performing features were selected from various regions and then combined.

Methods

A radio‐frequency data set consisting of 103 breast lesions was used in the authors’ analysis. Maps of homodyned K distribution parameters were created using an algorithm based on signal‐to‐noise ratio, kurtosis, and skewness of fractional‐order envelope moments. A Markov random field model was used to segment parametric maps. Features of different segments were extracted and evaluated based on bootstrapping and the receiver operating characteristic curve. To determine the best‐performing feature subset, the authors applied the joint mutual information criterion.

Results

It was found that there were individual features which performed better than the ones commonly used for lesion characterization, like the parameter obtained through averaging of values over the whole lesion. The authors selected and discussed the best‐performing features. Properties of different extracted regions were important and improved the distinction between benign and malignant tumors. The best performance was obtained by combining four features with the area under the receiver operating curve of 0.84.

Conclusions

The study showed that the analysis of internal changes in lesion parametric maps leads to a better classification of breast tumors. The authors recommend combining multiple features for characterization, instead of using only one parameter, especially in the case of heterogeneous lesions.
Laser Doppler velocimetry using a modified computer mouse
Authors: Zaron Edward D.
Published: September 2016

A computer mouse has been modified for use as a low-cost laser Doppler interferometer and used to measure the two-component fluid velocity of a flowing soap film. The mouse sensor contains two vertical cavity surface emitting lasers, photodiodes, and signal processing hardware integrated into a single package, approximately 1 cm2 in size, and interfaces to a host computer via a standard USB port. Using the principle of self-mixing interferometry, whereby laser light re-enters the laser cavity after being scattered from a moving target, the Doppler shift and velocity of scatterers dispersed in the flow are measured. Observations of the boundary layer in a turbulent soap film channel flow demonstrate the capabilities of the sensor.
Resource Letter MP-3: The Manhattan Project and Related Nuclear Research
Authors: Reed B. Cameron
Published: September 2016

This Resource Letter is a supplement to the earlier Resource Letters MP-1 and MP-2, and provides further sources on the Manhattan Project and related research. Books, review papers, journal articles, videos, and websites are cited for the following topics: general works, technical works, biographical and autobiographical works, foreign wartime nuclear programs and related allied intelligence, the use of the bombs against Hiroshima and Nagasaki, technical papers of historical interest, postwar policy and technical developments, and educational materials. Together, these three Resource Letters describe nearly 400 sources of information on the Manhattan Project.
No foie gras with apolipoprotein B inhibitors?
Authors: Brown J. Mark
Published: September 2016

Antisense oligonucleotide-mediated knockdown of apolipoprotein B results in compensatory autophagy to avoid hepatic steatosis.
Everything you splice can and will be used against you
Authors: Gill Saar
Published: September 2016

Leukemia progenitor cells are characterized by unique splice isoform patterns and are selectively sensitized to spliceosome modulation.
Irreversible electroporation in the curative treatment of Ewing's sarcoma
Authors: Steinbrecher Kacie , Arslan Bulent , Nassin Michele L , Kent Paul
Published: September 2016

Ewing's sarcoma (ES) is the second most common paediatric cancer of the bone. Standard therapy includes surgery or radiation for local control of primary and relapsed lesions and chemotherapy for systemic control. Irreversible electroporation (IRE), which uses short electrical pulses to induce pores and ablate neoplastic cells, has emerged as an alternative method of local control for inoperable metastatic liver and lung lesions. We present the first case in which IRE was used for local control of bony ES. This method has achieved successful local tumour control in our patient for 3 years.
Proposing evidence-based strategies to strengthen implementation of healthcare reform in resource-limited settings: a summative analysis
Authors: Manyazewal Tsegahun , Oosthuizen Martha J , Matlakala Mokgadi C
Published: September 2016

Objectives

Many resource-limited countries have adopted and implemented healthcare reform to improve the quality of healthcare, but few have had much impact and strategies in support of these efforts remain limited. We aimed to explore and propose evidence-based strategies to strengthen implementation of healthcare reform in resource-limited settings.

Design

Descriptive and exploratory designs in two phases. Phase I involved assessing the effectiveness of the healthcare reform implemented in Ethiopia in the form of business process reengineering, with evidence compiled from healthcare professionals through a self-administered questionnaire; and phase II involved proposing strategies and seeking consensus from experts using Delphi method.

Setting

Public hospitals in central Ethiopia.

Participants

406 healthcare professionals and 10 senior health policy experts.

Findings

The healthcare reform that we evaluated was able to restructure hospital departments into case teams, with the goal of adopting a ‘one-stop shopping’ approach. However, shortages of critical infrastructure, furniture and supplies and job dissatisfaction continued to hamper the system. The most important predictors that influenced implementation of the reform were financial resources, top management commitment and support, collaborative working environment and information technology (IT). Five strategies with 14 operational objectives and 67 potential interventions that could strengthen the reform are proposed based on their strategic priority, which are as follows: reinforce patient-centred quality of care services; foster a healthy and respectful workforce environment; efficient and accountable leadership and governance; efficient use of hospital financing and maximise innovations and the use of health technologies.

Conclusions

Effective implementation of healthcare reform remained a challenge for governments in resource-limited settings. Resilient operational, clinical and governance functions of health systems, as well as a motivated and committed health workforce, are important to move healthcare reform processes forward. Political commitments at this juncture might be critical though there need to be a clear demarcation between political and technical engagements.
Manitoba mothers and fetal alcohol spectrum disorders study (MBMomsFASD): protocol for a population-based cohort study using linked administrative data
Authors: Singal Deepa , Brownell Marni , Hanlon-Dearman Ana , Chateau Dan , Longstaffe Sally , Roos Leslie L
Published: September 2016

Introduction

Fetal alcohol spectrum disorder (FASD) is a significant public health concern. To prevent FASD, factors that place women at risk for giving birth to children with FASD must be investigated; however, there are little data in this area. This paper describes the development of the Manitoba mothers and FASD study, a retrospective cohort of mothers whose children were diagnosed with FASD, generated to investigate: (1) risk factors associated with giving birth to children with FASD; (2) maternal physical and health outcomes, as well as the usage of health and social services.

Methods

The study population will be identified by linking children diagnosed with FASD from a provincially centralised FASD assessment clinic (from 31 March 1999 to 31 March 2012) to their birth mothers using de-identified administrative health data housed at the Manitoba Centre for Health Policy. Preliminary analysis has identified over 700 mothers, which is the largest sample size in this field to date. A comparison cohort of women with children who did not have an FASD diagnosis matched on the region of residence, date of birth of child with FASD and socioeconomic status will be generated to compare exposures and outcomes. Potential demographic, socioeconomic, family history, and physical and mental health risk factors will be investigated by linking a range of health and social databases, furthering insight into the root causes of drinking during pregnancy. The longitudinal data will allow us to document the usage patterns of healthcare and social services throughout significant periods in these women's lives to identify opportunities for prevention.

Ethics and dissemination

Ethical approval has been obtained by the University of Manitoba's Health Research Ethics Board and the Manitoba Health Information Privacy Committee. Dissemination of study results will include engagement of stakeholders and policymakers through presentations and reports for policymakers, in parallel with scientific papers.
All Patients with Diabetes Should Have Annual UACR Tests. Why is That So Hard?
Authors: Willison Alice , Tully Vicki , Davey Peter
Published: September 2016

The urine albumin creatinine ratio (UACR) detects abnormal levels of protein in the urine and should be performed annually to detect kidney disease in patients with diabetes mellitus. UK national audits show that 25% of patients do not have annual tests and our data suggested that some patients had more than one test per year.

Data from 20 patients showed that 55% had more than one UACR test per year, with a total of 19 unnecessary tests at an estimated cost of £20,000 per year. However 20% had not had a UACR in the previous year, so unreliable testing was potentially causing harm as well as waste. Process mapping showed that having a UACR test depended on whether the patient brought a urine sample to the clinic. Most (72%) patients were unaware that the urine sample was used to detect kidney damage. We encountered barriers when finding a process to automate measures of reliability of UACR testing using computer protocol, and therefore created a patient information leaflet. The first version of the leaflet was too technical and several changes were suggested by patients. After reading the revised leaflet 99% of patients understood the reason for UACR testing and 64% felt more motivated to bring in urine samples. The phlebotomist disseminated the patient information leaflet with a median of 90% reliability for six consecutive clinics. The patient information leaflet has the potential to improve patient involvement in their care and to increase the number of patients who bring urine samples to the clinic. However, this could increase the number of unnecessary tests unless the process of test ordering is changed to ensure that UACR is only measured annually.
Patients’ perceptions and views of surgery and radioiodine ablation in the definitive management of Graves’ disease
Authors: Hookham Jessica , Truran Peter , Allahabadia Amit , Balasubramanian Sabapathy P
Published: September 2016

Background

Patients’ perceptions and preferences influence the choice of radioiodine ablation (RIA) or surgery in the definitive management of Graves’ disease. This study aimed to evaluate their concerns, experiences and satisfaction following definitive treatment.

Methods

A postal survey of patients who had treatment with surgery or RIA between January 2011 and June 2013 for Graves’ disease was conducted.

Results

Of 214 patients, 136 (64%) responded. The majority of patients felt actively involved in decision making (83.8%) and were satisfied (84.9%) with their treatment. Compared with RIA, patients who underwent surgery were more satisfied with their treatment (p=0.008). Discussion with the doctor was the most useful aid to decision making. Feeling involved in decision-making process was associated with improved satisfaction (p<0.001).

Common reasons for not choosing surgery were need for general anaesthesia, scarring and voice change. Avoiding close contact, risk of persistent hyperthyroidism and worsening eye disease were common reasons for not choosing RIA. Ongoing concerns were hypothyroidism, scarring and eye problems after surgery and hypothyroidism and eye problems after RIA.

Conclusions

This study provides insight into patients’ experiences of surgery and RIA for Graves’ disease and reinforces the importance of patient involvement in the decision-making process.
Alterations in the echocardiographic variables of the right ventricle in asymptomatic patients with breast cancer during anthracycline chemotherapy
Authors: Abdar Esfahani Morteza , Mokarian Fariborz , Karimipanah Mohammad
Published: September 2016

Background

Anthracycline-induced cardiotoxicity can reach an irreversible phase; therefore great efforts are made to diagnose it early. As the right ventricle (RV) is smaller than the left, the right side of the heart is probably influenced by anthracycline to a greater extent and in a shorter time. The purpose of the present study was to investigate the early effects of chemotherapy on the right side of the heart.

Methods

This cross-sectional study was performed in Isfahan University hospitals from August 2014 to December 2015. Subjects were 67 patients with breast cancer who were planned to receive anthracycline for the first time. Echocardiography was performed before administration of anthracycline and 6 months later. Variables included right heart measures (RV end-diastolic dimensions, right atrium length and diameter), RV fractional area change (RVFAC), index of myocardial performance (Tei index), tricuspid annular plane systolic excursion (TAPSE), pulmonary artery systolic pressure, lateral tricuspid annular early and late diastolic velocities, and tissue Doppler diastolic and systolic velocities.

Results

Forty-nine of the subjects completed the study. RV end-diastolic diameters and Tei index (0.31 to 0.37) were significantly increased (p<0.001). RVFAC (49.83% to 43.59%) and TAPSE (18.8 to 17.7 mm) were significantly decreased (p<0.001). There was a significant reduction in E (57.06 to 46.59 cm/s, p<0.001), E/A ratio (1.42 to 1.18, p<0.001), E′ (16.73 to 12.4 cm/s, p<0.001), E′/A′ ratio (1.21 to 0.9, p<0.001) and S′ (12.59 to 10.57 cm/s, p<0.001). Systolic pulmonary arterial pressure (20.63 to 22.24 mm Hg, p=0.04) was significantly increased.

Conclusions

This study shows a significant decrease in RV systolic and diastolic function during chemotherapy for 6 months. These reductions are in the normal range and can probably be considered an early indicator of anthracycline-induced cardiotoxicity.
Effect of the BSCCO superconducting properties by tiny Y2O3 addition
Authors: Dong Yan , Sun Aimin , Xu Bin , Zhang Hongtao , Zhang Meng
Published: September 2016

In this paper, the effect of tiny Y2O3 addition in (Bi,[Formula: see text]Pb)-2223 superconductor prepared by solid state reaction technique was studied. The properties of samples have been investigated via X-ray diffraction (XRD), resistance–temperature ([Formula: see text]–[Formula: see text]) curve, scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). XRD data indicated that all samples are multiphase and the major phases are high-temperature phases and low-temperature phases. The volume fraction of (Bi,[Formula: see text]Pb)-2223 is not great change with tiny Y2O3 addition. All samples exhibit superconducting phase with the critical transition temperature and one-step transition, however, the transition width was decreased with the Y2O3 addition up to 0.04 wt.% and sharp increased with the excessive oxide addition. SEM pictures show that the Y2O3 appeared on the flake-type grains surface obviously, but the number and size of the hole between grains are decreased in the 0.04 wt.% addition.
Two-party quantum key agreement protocol with four-particle entangled states
Authors: He Yefeng , Ma Wenping
Published: September 2016

Based on four-particle entangled states and the delayed measurement technique, a two-party quantum key agreement protocol is proposed in this paper. In the protocol, two participants can deduce the measurement results of each other’s initial quantum states in terms of the measurement correlation property of four-particle entangled states. According to the corresponding initial quantum states deduced by themselves, two parties can extract the secret keys of each other by using the publicly announced value or by performing the delayed measurement, respectively. This guarantees the fair establishment of a shared key. Since each particle in quantum channel is transmitted only once, the protocol is congenitally free from the Trojan horse attacks. The security analysis shows that the protocol not only can resist against both participant and outsider attacks but also has no information leakage problem. Moreover, it has high qubit efficiency.
Role of defects, resonances, anharmonicities and electron–phonon scattering processes on thermal conductivity of YBa2Cu3O7−δ
Authors: Ashokan Vinod , Indu B. D. , Dimri A. Kr.
Published: September 2016

In this work, thermal conductivity of high temperature superconductors (HTS) has been analyzed on the basis of modified Callaway model. In the new formulation, the relaxation times of various contributing processes have been observed in newer perspectives of electron and phonon line widths. To obtain line widths, the quantum dynamics of electron and phonon is carried out by using double time thermodynamic Green’s functions method via a general Hamiltonian. The outcome of this heuristic approach is utilized to successfully explain the spectacular behavior of thermal conductivity of HTS, and particularly in the vicinity of transition temperature.
Phase transition at N = 92 in 158Dy
Authors: Gupta J. B.
Published: September 2016

Beyond the shape phase transition from the spherical vibrator to the deformed rotor regime at [Formula: see text], the interplay of [Formula: see text]- and [Formula: see text]-degrees of freedom becomes important, which affects the relative positions of the [Formula: see text]- and [Formula: see text]-bands. In the microscopic approach of the dynamic pairing plus quadrupole model, a correlation of the strength of the quadrupole force and the formation of the [Formula: see text]- and [Formula: see text]-bands in [Formula: see text]Dy is described. The role of the potential energy surface is illustrated. The [Formula: see text] transition rates in the lower three [Formula: see text]-bands and the multi-phonon bands with [Formula: see text] and [Formula: see text] are well reproduced. The absolute [Formula: see text] [Formula: see text] serves as a good measure of the quadrupole strength. The role of the single particle Nilsson orbits is also described.
EFFECTS OFTARAXACUM MONGOLICUMEXTRACT ON LIPOPOLYSACCHARIDE-INDUCED NITRIC OXIDE AND CYTOKINES PRODUCTION BY BOVINE PERIPHERAL BLOOD MONONUCLEAR CELLS
Authors: Lee Kuo-Hua , Hsu Kai-Chen , Wang Yu-Shan , Yeh Chia-Chou , Chen Jih-Yih , Wang Szu-Han , Jea Yu-Shine , Chi Chau-Hwa
Published: September 2016

The objective of this study is to investigate Taraxacum mongolicum (TM) as a therapeutic alternative for preventing and treating bovine mastitis. The effect of the anti-inflammatory activity of Taraxacum mongolicum extract (TME) on lipopolysaccharide (LPS)-induced responses was studied in the bovine peripheral blood mononuclear cells (PBMCs). The dried plant TM was extracted with 10 volumes of distilled water to generate its water extract. PBMCs were pretreated with various concentrations of TME (0, 1, 10, 100, 1000 [Formula: see text]g/mL) and subsequently incubated with LPS (1 [Formula: see text]g/mL). Cell viability was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenylthiazolium bromide (MTT) assay. The level of nitric oxide (NO) was determined by using Griess reagent assay. The mRNA expression levels of pro-inflammatory cytokines including interleukin (IL)-1[Formula: see text], IL-6, IL-8, tumor necrosis factor (TNF)-[Formula: see text] and granulocyte chemotactic protein (GCP)-2 were determined by using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The results showed no significant cytotoxic effects on the PBMCs at various treated concentrations of TME. Treatment of TME (100 and 1000 [Formula: see text]g/mL) significantly inhibited NO production in LPS-stimulated PBMCs. TME (10 [Formula: see text]g/mL) significantly inhibited LPS-stimulated IL-1[Formula: see text], IL-6, IL-8, TNF-[Formula: see text] and GCP-2 mRNA expression in PBMCs at a time-dependent manner. In this article, we reported for the first time that TME significantly inhibited production of NO and pro-inflammatory cytokines in LPS-stimulated PBMCs. This finding could be useful for clinical practice in preventing and treating bovine mastitis.
Incorporating geomorphology in engineering geological ground models
Authors: Griffiths J. S.
Published: September 2016

Ground models should be a fundamental outcome from all site investigations for civil engineering development and planning projects. Without them, it is not possible to: define the ground conditions; identify any geohazards or other engineering constraints; identify potential resources; provide a basis for construction tendering; establish risk registers; determine reference conditions; design the works; or evaluate the environmental consequences of projects. A methodology for ground model development has yet to be fully established, but understanding geomorphological processes and landforms is central to the creation of effective models. Therefore, it is necessary to develop a methodology that ensures geomorphology is fully integrated into the already well-defined approaches for investigating and interpreting the geological and geotechnical conditions. This happens most effectively where geomorphology is seen as part of engineering geology and is fully integrated in the site investigation process. This is not a universal situation however, as a great deal of geomorphological research is undertaken as part of physical geography and is not widely accessed during standard desk studies. Engineering geologists need to access this high-quality research and bring it into ground models that are presently biased towards geology and geotechnics. When this is achieved, engineering geological ground models will become genuinely fit for purpose.
Siting method of the ancients in the excavation of Longyou Caverns, 2000 years ago
Authors: Li Lihui , Deng Xiaolong , Tan Yufang , Huang Beixiu , Yang Zhifa
Published: September 2016

In June 1992, five large rock caverns were unearthed in a village near Longyou County in Zhejiang Province, south China. The caverns were manually excavated about 2000 years ago in argillaceous siltstone of Cretaceous age. Faults are not well developed, however there are clay interlayers within argillaceous siltstone bedding at each cavern. Field investigations suggest that the ancients had realized the influence of the clay interlayers on the stability of caverns and altered their location and layout accordingly. Several preserved trial adits at the site are good evidence of this conclusion. These adits are apparently abandoned due to the presence of clay interlayers. This is probably the earliest known use of geological exploration by adit methods, an approach now widely used. In this paper, the engineering geological conditions, especially the development of the clay interlayers, are presented in some detail. Statistical analysis shows that the numbers and average thickness of clay interlayers in the five completed caverns are less than those in other outcrops. It is concluded that trial adit methods and experience by geological observation were adopted by the ancients 2000 years ago in the excavation of underground rock caverns.
Intelligent Biohazard Training Based on Real-Time Task Recognition
Authors: Prendinger Helmut , Alvarez Nahum , Sanchez-Ruiz Antonio , Cavazza Marc , Catarino joão , Oliveira João , Prada Rui , Fujimoto Shuji , Shigematsu Mika
Published: September 2016

Virtual environments offer an ideal setting to develop intelligent training applications. Yet, their ability to support complex procedures depends on the appropriate integration of knowledge-based techniques and natural interaction. In this article, we describe the implementation of an intelligent rehearsal system for biohazard laboratory procedures, based on the real-time instantiation of task models from the trainee’s actions. A virtual biohazard laboratory has been recreated using the Unity3D engine, in which users interact with laboratory objects using keyboard/mouse input or hand gestures through a Kinect device. Realistic behavior for objects is supported by the implementation of a relevant subset of common sense and physics knowledge. User interaction with objects leads to the recognition of specific actions, which are used to progressively instantiate a task-based representation of biohazard procedures. The dynamics of this instantiation process supports trainee evaluation as well as real-time assistance. This system is designed primarily as a rehearsal system providing real-time advice and supporting user performance evaluation. We provide detailed examples illustrating error detection and recovery, and results from on-site testing with students from the Faculty of Medical Sciences at Kyushu University. In the study, we investigate the usability aspect by comparing interaction with mouse and Kinect devices and the effect of real-time task recognition on recovery time after user mistakes.
Efficient Computation of Representative Families with Applications in Parameterized and Exact Algorithms
Authors: Fomin Fedor V. , Lokshtanov Daniel , Panolan Fahad , Saurabh Saket
Published: September 2016

Let
M
=(
E
,
I
) be a matroid and let
S
={
S
1
, ċ ,
S
t
} be a family of subsets of
E
of size
p
. A subfamily
Ŝ
⊆
S
is
q
-
representative
for
S
if for every set
Y
⊆
E
of size at most
q
, if there is a set
X
∈
S
disjoint from
Y
with
X
∪
Y
∈
I
, then there is a set
Xˆ
∈
Ŝ
disjoint from
Y
with
Xˆ
∪
Y
∈
I
. By the classic result of Bollobás, in a uniform matroid, every family of sets of size
p
has a
q
-representative family with at most (

p
+
q

p

) sets. In his famous “two families theorem” from 1977, Lovász proved that the same bound also holds for any matroid representable over a field F. We give an efficient construction of a
q
-representative family of size at most (

p
+
q

p

) in time bounded by a polynomial in (

p
+
q

p

),
t
, and the time required for field operations.

We demonstrate how the efficient construction of representative families can be a powerful tool for designing single-exponential parameterized and exact exponential time algorithms. The applications of our approach include the following:

—In the L
ong
D
irected
C
ycle
problem, the input is a directed
n
-vertex graph
G
and the positive integer
k
. The task is to find a directed cycle of length at least
k
in
G
, if such a cycle exists. As a consequence of our 6.75

k
+
o
(
k
)

n

O
(1)

time algorithm, we have that a directed cycle of length at least log
n
, if such a cycle exists, can be found in polynomial time.

—In the M
inimum
E
quivalent
G
raph
(MEG) problem, we are seeking a spanning subdigraph
D
′ of a given
n
-vertex digraph
D
with as few arcs as possible in which the reachability relation is the same as in the original digraph
D
.

—We provide an alternative proof of the recent results for algorithms on graphs of bounded treewidth showing that many “connectivity” problems such as H
amiltonian
C
ycle
or S
teiner
T
ree
can be solved in time 2

O
(
t
)

n on
n
-vertex graphs of treewidth at most
t
.

For the special case of uniform matroids on
n
elements, we give a faster algorithm to compute a representative family. We use this algorithm to provide the fastest known deterministic parameterized algorithms for
k
-P
ath
,
k
-T
ree
, and, more generally,
k
-S
ubgraph
I
somorphism
, where the
k
-vertex pattern graph is of constant treewidth.
A Unified Point-of-Interest Recommendation Framework in Location-Based Social Networks
Authors: Cheng Chen , Yang Haiqin , King Irwin , Lyu Michael R.
Published: September 2016

Location-based social networks (LBSNs), such as Gowalla, Facebook, Foursquare, Brightkite, and so on, have attracted millions of users to share their social friendship and their locations via check-ins in the past few years. Plenty of valuable information is accumulated based on the check-in behaviors, which makes it possible to learn users’ moving patterns as well as their preferences. In LBSNs, point-of-interest (POI) recommendation is one of the most significant tasks because it can help targeted users explore their surroundings as well as help third-party developers provide personalized services. Matrix factorization is a promising method for this task because it can capture users’ preferences to locations and is widely adopted in traditional recommender systems such as movie recommendation. However, the sparsity of the check-in data makes it difficult to capture users’ preferences accurately. Geographical influence can help alleviate this problem and have a large impact on the final recommendation result. By studying users’ moving patterns, we find that users tend to check in around several centers and different users have different numbers of centers. Based on this, we propose a Multi-center Gaussian Model (MGM) to capture this pattern via modeling the probability of a user’s check-in on a location. Moreover, users are usually more interested in the top 20 or even top 10 recommended POIs, which makes personalized ranking important in this task. From previous work, directly optimizing for pairwise ranking like Bayesian Personalized Ranking (BPR) achieves better performance in the top-
k
recommendation than directly using matrix matrix factorization that aims to minimize the point-wise rating error. To consider users’ preferences, geographical influence and personalized ranking, we propose a unified POI recommendation framework, which unifies all of them together. Specifically, we first fuse MGM with matrix factorization methods and further with BPR using two different approaches. We conduct experiments on Gowalla and Foursquare datasets, which are two large-scale real-world LBSN datasets publicly available online. The results on both datasets show that our unified POI recommendation framework can produce better performance.
Optimal Mechanisms for Combinatorial Auctions and Combinatorial Public Projects via Convex Rounding
Authors: Dughmi Shaddin , Roughgarden Tim , Yan Qiqi
Published: September 2016

We design the first truthful-in-expectation, constant-factor approximation mechanisms for
NP
-hard cases of the welfare maximization problem in combinatorial auctions with nonidentical items and in combinatorial public projects. Our results apply to bidders with valuations that are nonnegative linear combinations of gross-substitute valuations, a class that encompasses many of the most well-studied subclasses of submodular functions, including coverage functions and weighted matroid rank functions. Our mechanisms have an expected polynomial runtime and achieve an approximation factor of 1 − 1/
e
. This approximation factor is the best possible for both problems, even for known and explicitly given coverage valuations, assuming
P
≠
NP
. Recent impossibility results suggest that our results cannot be extended to a significantly larger valuation class.

Both of our mechanisms are instantiations of a new framework for designing approximation mechanisms based on randomized rounding algorithms. The high-level idea of this framework is to optimize
directly over the (random) output of the rounding algorithm
, rather than the usual (and rarely truthful) approach of optimizing over the
input
to the rounding algorithm. This framework yields truthful-in-expectation mechanisms, which can be implemented efficiently when the corresponding objective function is concave. For bidders with valuations in the cone generated by gross-substitute valuations, we give novel randomized rounding algorithms that lead to both a concave objective function and a (1 − 1/
e
)-approximation of the optimal welfare.