Analysis of Droplet Train/Moving Substrate Interactions in Ink-Jetting Processes

Ink-jetting technology has been applied to several processes in solid free-form fabrication (SFF) wherein droplets impinge onto a substrate to deposit the build material. Droplet impact behaviour on a surface has been the interest of many researchers; however, few studies have been undertaken to investigate the interaction of droplets with the moving substrate. This paper reports the impact behaviour of the droplets jetted at different frequencies onto a substrate moving over a range of velocities. The phenomena associated with the interaction were classified into three main regimes.Mechanical Engineerin

Gap modification of atomically thin boron nitride by phonon mediated interactions

A theory is presented for the modification of bandgaps in atomically thin boron nitride (BN) by attractive interactions mediated through phonons in a polarizable substrate, or in the BN plane. Gap equations are solved, and gap enhancements are found to range up to 70% for dimensionless electron-phonon coupling \lambda=1, indicating that a proportion of the measured BN bandgap may have a phonon origin

New polymerization-mixture formulation for jetting: An approach to production of polyamide 6 parts

Poor mechanical properties of manufactured parts is one of the main problems in most of the RP and RM processes. This work deals with a study on formulation of new polymerization mixtures with the aim of being used in jetting process. Two different catalyst components were compared in order to shorten the solidification time and improve the final properties of the manufactured part. The feasibility of jetting polymerization mixtures at jetting head temperature was also investigated. Different characterization and visualization methods (i.e. such as DSC, viscometry, TGA, and hot stage optical microscopy) were used to monitor the polymerization progress and manufactured part properties.Mechanical Engineerin

Optimal interlayer hopping and high temperature Bose–Einstein condensation of local pairs in quasi 2D superconductors

Both FeSe and cuprate superconductors are quasi 2D materials with high transition temperatures and local fermion pairs. Motivated by such systems, we investigate real space pairing of fermions in an anisotropic lattice model with intersite attraction, V, and strong local Coulomb repulsion, U, leading to a determination of the optimal conditions for superconductivity from Bose–Einstein condensation. Our aim is to gain insight as to why high temperature superconductors tend to be quasi 2D. We make both analytically and numerically exact solutions for two body local pairing applicable to intermediate and strong V. We find that the Bose–Einstein condensation temperature of such local pairs pairs is maximal when hopping between layers is intermediate relative to in-plane hopping, indicating that the quasi 2D nature of unconventional superconductors has an important contribution to their high transition temperatures

A novel FLEX supplemented QMC approach to the Hubbard model

This paper introduces a novel ansatz-based technique for solution of the Hubbard model over two length scales. Short range correlations are treated exactly using a dynamical cluster approximation QMC simulation, while longer-length-scale physics requiring larger cluster sizes is incorporated through the introduction of the fluctuation exchange (FLEX) approximation. The properties of the resulting hybrid scheme are examined, and the description of local moment formation is compared to exact results in 1D. The effects of electron-electron coupling and electron doping on the shape of the Fermi-surface are demonstrated in 2D. Causality is examined in both 1D and 2D. We find that the scheme is successful if QMC clusters of $N_C\ge 4$ are used (with sufficiently high temperatures in 1D), however very small QMC clusters of $N_C=1$ lead to acausal results

Towards analytical approaches to the dynamical-cluster approximation

I introduce several simplified schemes for the approximation of the self-consistency condition of the dynamical cluster approximation. The applicability of the schemes is tested numerically using the fluctuation-exchange approximation as a cluster solver for the Hubbard model. Thermodynamic properties are found to be practically indistinguishable from those computed using the full self-consistent scheme in all cases where the non-interacting partial density of states is replaced by simplified analytic forms with matching 1st and 2nd moments. Green functions are also compared and found to be in close agreement, and the density of states computed using Pad\'{e} approximant analytic continuation shows that dynamical properties can also be approximated effectively. Extensions to two-particle properties and multiple bands are discussed. Simplified approaches to the dynamical cluster approximation should lead to new analytic solutions of the Hubbard and other models

Predictors of preeclampsia in women in the metformin in gestational diabetes (MiG) study

Background: Gestational Diabetes Mellitus (GDM), maternal obesity and pregnancy weight gain are associated with an increased risk of developing Preeclampsia (PE). The aim of this study was to examine the predictors of PE in women commencing pharmacotherapy for GDM in the Metformin in Gestational diabetes trial.Methods: Descriptive and logistic regression analyses examined the relationship between maternal enrolment characteristics and later development of PE.Results: 46 (6.3%) of 703 women developed PE. At enrolment ((30 (SD3.2) weeks gestation), women who later developed PE had higher HbA1c (6.14% (95% CI 5.84, 6.45) vs. 5.73% (95% CI 5.67, 5.78), P = 0.003), fasting triglycerides (2.93 mmol/L (95% CI 2.57, 3.29) vs. 2.55mmol/L (95% CI 2.47, 2.62), P = 0.03) and blood pressure. Their infants were born 9 days earlier (P < 0.001) but were otherwise not different. In univariate analysis, the strongest positive predictors for PE were Polynesian ethnicity (OR 2.75 (95% CI 1.48, 5.09), P= 0.001), personal or family history of PE (OR 2.65 (95% CI 1.36, 5.16), P=0.004), maternal HbA1c (OR 1.96 (95% CI 1.35, 2.89), P< 0.001), triglycerides (OR 1.45 (95% CI 1.07,1.97), P=0.002), and weight gain from early pregnancy (OR 1.09 (95% CI 1.03,1.17), P=0.01). HDL-C was a negative predictor of PE (OR 0.29 (95% CI 0.09, 0.94), P= 0.04).Following adjustment for Polynesian ethnicity and personal or family history of PE, and when further adjusted for HbA1c or early pregnancy BMI, these variables remained significant.Conclusion: Treatment allocation and BMI were not associated with risk of PE. Personal or family history of PE, Polynesian ethnicity, degree of hyperglycemia, maternal triglycerides and weight gain prior to treatment signal increased risk of subsequent PE in women needing pharmacotherapy for GDM

Homogeneous Fermion Superfluid with Unequal Spin Populations

For decades, the conventional view is that an s-wave BCS superfluid can not support uniform spin polarization due to a gap $\Delta$ in the quasiparticle excitation spectrum. We show that this is an artifact of the dismissal of quasiparticle interactions $V_{qp}^{}$ in the conventional approach at the outset. Such interactions can cause triplet fluctuations in the ground state and hence non-zero spin polarization at "magnetic field" $h<\Delta$. The resulting ground state is a pairing state of quasiparticles on the ``BCS vacuum". For sufficiently large $V_{qp}$, the spin polarization of at unitarity has the simple form $m\propto \mu^{1/2}$. Our study is motivated by the recent experiments at Rice which found evidence of a homogenous superfluid state with uniform spin polarization.Comment: 4 pages, 3 figure

Electrically pumped single-defect light emitters in WSe2_2

Recent developments in fabrication of van der Waals heterostructures enable new type of devices assembled by stacking atomically thin layers of two-dimensional materials. Using this approach, we fabricate light-emitting devices based on a monolayer WSe$_2$, and also comprising boron nitride tunnelling barriers and graphene electrodes, and observe sharp luminescence spectra from individual defects in WSe$_2$ under both optical and electrical excitation. This paves the way towards the realization of electrically-pumped quantum emitters in atomically thin semiconductors. In addition we demonstrate tuning by more than 1 meV of the emission energy of the defect luminescence by applying a vertical electric field. This provides an estimate of the permanent electric dipole created by the corresponding electron-hole pair. The light-emitting devices investigated in our work can be assembled on a variety of substrates enabling a route to integration of electrically pumped single quantum emitters with existing technologies in nano-photonics and optoelectronics

Recruitment strategies in randomised controlled trials of men aged 50 years and older: a systematic review

Objectives: To identify and review evaluations of strategies to recruit men aged 50 years and over to randomised controlled trials (RCTs). Design: Systematic review and narrative synthesis. Data Sources: MEDLINE, EMBASE, CINAHL and ORRCA databases were searched to 1 December 2017. Eligibility Criteria: Studies using quantitative methods to evaluate recruitment strategies to RCTs of men aged 50 years and older. Data Extraction and Synthesis: A single reviewer extracted data (for each strategy, number of participants approached, screened and randomised, and cost). Study quality was assessed using National Heart, Lung and Blood Institute Quality Assessment Tools and considered study design, description of interventions, description and measurement of outcomes, completeness of outcome reporting, performance of statistical testing and consideration of confounders. Recruitment strategies were categorised by the recruitment stage they addressed. Results: Sixteen studies (n >14 000) were included: one good quality, ten fair quality and five poor quality. Studies evaluated strategies to identify prospective participants, and to improve the processes for assessing participant eligibility, providing participant information and seeking consent. In good and fair quality studies, the most effective strategies for identifying participants were referral from an affiliated health service provider (two studies), mass mailing (five studies) and media coverage (two studies). Community outreach activities such as displaying posters and attending local community events were not effective (two studies). Trial-specific training of site recruitment staff, developed using qualitative analysis of recruitment visits (two studies), and provision of study information to prospective participants at a multidisciplinary, group information session (one study) both improved recruitment. Conclusion: Improved engagement of men aged 50 years and older in RCTs is needed. A gender-sensitised approach to RCT recruitment may help to address this need. We have identified several promising recruitment strategies that merit further evaluation.Karen Bracken, Lisa Askie, Anthony C Keech, Wendy Hague, Gary Witter