Investigation of asymmetrical shaft power increase during ship maneuvers by means of simulation techniques

Marine propulsion plants can experience large power fluctuations during tight maneuvers, with increases of shaft torque up to and over 100% of the steady values in straight course and considerable asymmetry between internal and external shafts during turning circle. This phenomenon (studied in Viviani et al 2007a and 2007b can be of particular interest for twin screw ships propulsion systems with coupled shaftlines, in which asymmetrical loads can represent a challenge for the whole propulsion system (e.g. unique reduction gear, shaftlines, automation). A joint research has been set up in order to deeply investigate the phenomenon, by means of large scale model testing and related numerical simulations. In the present work, preliminary simulation results with different simplified automation systems and with an automation system more similar to the real one are reported, allowing to get a better insight into this complex problem

Precise Measurements of Atmospheric Muon Fluxes with the BESS Spectrometer

The vertical absolute fluxes of atmospheric muons and muon charge ratio have been measured precisely at different geomagnetic locations by using the BESS spectrometer. The observations had been performed at sea level (30 m above sea level) in Tsukuba, Japan, and at 360 m above sea level in Lynn Lake, Canada. The vertical cutoff rigidities in Tsukuba (36.2 N, 140.1 E) and in Lynn Lake (56.5 N, 101.0 W) are 11.4 GV and 0.4 GV, respectively. We have obtained vertical fluxes of positive and negative muons in a momentum range from 0.6 to 20 GeV/c with systematic errors less than 3 % in both measurements. By comparing the data collected at two different geomagnetic latitudes, we have seen an effect of cutoff rigidity. The dependence on the atmospheric pressure and temperature, and the solar modulation effect have been also clearly observed. We also clearly observed the decrease of charge ratio of muons at low momentum side with at higher cutoff rigidity region.Comment: 35 pages, 9 figures. Submitted to Astroparticle Physic

Early and Late Response and Glucocorticoid-Sparing Effect of Belimumab in Patients with Systemic Lupus Erythematosus with Joint and Skin Manifestations: Results from the Belimumab in Real Life Setting Study—Joint and Skin (BeRLiSS-JS)

Aim. To assess the efficacy of belimumab in joint and skin manifestations in a nationwide cohort of patients with SLE. Methods. All patients with skin and joint involvement enrolled in the BeRLiSS cohort were considered. Belimumab (intravenous, 10 mg/kg) effectiveness in joint and skin manifestations was assessed by DAS28 and CLASI, respectively. Attainment and predictors of DAS28 remission (<2.6) and LDA (≥2.6, ≤3.2), CLASI = 0, 1, and improvement in DAS28 and CLASI indices ≥20%, ≥50%, and ≥70% were evaluated at 6, 12, 24, and 36 months. Results. DAS28 < 2.6 was achieved by 46%, 57%, and 71% of patients at 6, 12, and 24 months, respectively. CLASI = 0 was achieved by 36%, 48%, and 62% of patients at 6, 12, and 24 months, respectively. Belimumab showed a glucocorticoid-sparing effect, being glucocorticoid-free at 8.5%, 15.4%, 25.6%, and 31.6% of patients at 6, 12, 24, and 36 months, respectively. Patients achieving DAS-LDA and CLASI-50 at 6 months had a higher probability of remission at 12 months compared with those who did not (p = 0.034 and p = 0.028, respectively). Conclusions. Belimumab led to clinical improvement in a significant proportion of patients with joint or skin involvement in a real-life setting and was associated with a glucocorticoid-sparing effect. A significant proportion of patients with a partial response at 6 months achieved remission later on during follow-up

Sturbridge Pedestrian Bridge Design

The goal of this project was to design a pedestrian bridge to cross the Quinebaug River, connecting the commercial district to the recreational trail system in Sturbridge, Massachusetts. First, the team developed design criteria, selected a location for the proposed bridge, and produced preliminary bridge designs. The final recommendation for this project is to build a partially- covered, truss bridge that spans the river. A full structural analysis and design were performed, and a final cost estimate was prepared

Wave Drift Forces Estimation for the Preliminary Design of Dynamic Positioning Systems

In present work, a simplified methodology able to provide a sufficiently accurate assessment of wave drift forces is presented, with the aim of providing a procedure which may be applied in the preliminary stages of the design, when the technical data of the ship (such as the hull forms) are not yet available, and only main hull parameters are present. In particular, the 3D panel seakeeping program PRECAL, developed at Cooperative Research Ships (CRS) is utilised. At first, its capabilities are verified comparing numerical results with literature data, showing the code reliability. Then, a series of simplified ellipsoidal hull forms have been analysed and compared with more complex hull forms in order to identify a criterion of equivalence, which may be used when a detailed description of the hullform is not available. Results show that the proposed simplified methodology is reliable and enough accurate to allow a proper sizing of the propulsion and manoeuvring systems of a ship with dynamic positioning requirements in the preliminary stage of the design

Alternative Methods for the Identification of Hydrodynamic Coefficients from Standard Manoeuvres

The problem of ship manoeuvrability has increasingly grown in consideration in the last decade, both for merchant and naval ships. With regards to merchant ships, the adoption by IMO of the RESOLUTION A.751(18) in 1993 [1] established minimum manoeuvrability standards to grant safety for all seagoing ships. With regards to naval ships, a strong interest has been manifested by NATO NG6, which established a Specialist Team in naval ship manoeuvrability with the aim of developing, at last, a standardised criteria. The work of this ST resulted in a first Working Paper [2] and a subsequent ANEP will be probably published by the end of the present year with a set of preliminary criteria. An estimation of ship manoeuvrability is strongly related to the accuracy in the determination of the hydrodynamic coefficients which specify the mathematical model of ship manoeuvring used in the existing prediction tools. These coefficients are usually estimated, in a preliminary stage of design, from regression formulas based on existing model-test data [3][4], which may lead to inaccurate predictions for non-conventional vessels or ships exceeding the parametric range of the experimental data base. The aim of the work presented in this paper is the development of a method to identify the hydrodynamic coefficients starting from standard experimental results in order to be able to extract data from the wide experimental data-base available (sea and model-tests trials); two different procedure for the identification of the hydrodynamic coefficients will be presented, with the comparison of their merits and shortcomings

Deal Me in: Playing Cards in the Home to Learn Math

Recent meta-analyses have demonstrated a significant association between children’s early math achievement and their experiences with math at home, including their caregivers’ talk about math. However, few studies have investigated the relations between caregiver math talk and children’s learning with experimental designs. Eighty-six children (M = 5.0 years) and their caregivers were randomly assigned to play either a numeracy or a shape card game at home for six weeks. Data were collected on children’s number and shape knowledge and families’ math talk during gameplay. There was substantial participant attrition (42% did not return completed materials), however, both an intent-to-treat analysis of the sample that received study materials and a subgroup analysis of study completers showed that children who played the shape game significantly improved their shape naming and matching skills relative to children who played the number game. Children who played the number game did not significantly improve their numerical skills relative to children who played the shape game. Mathematical talk during gameplay varied between families but was correlated over time within families. Caregivers’ and children’s talk about matching cards by shape or color predicted children’s learning from the shape game. The results suggest that despite receiving uniform instructions and materials, there was significant variability in children’s home math experiences that predicted their learning from the card game

Deal Me in: Playing Cards in the Home to Learn Math

Recent meta-analyses have demonstrated a significant association between children’s early math achievement and their experiences with math at home, including their caregivers’ talk about math. However, few studies have investigated the relations between caregiver math talk and children’s learning with experimental designs. Eighty-six children (M = 5.0 years) and their caregivers were randomly assigned to play either a numeracy or a shape card game at home for six weeks. Data were collected on children’s number and shape knowledge and families’ math talk during gameplay. There was substantial participant attrition (42% did not return completed materials), however, both an intent-to-treat analysis of the sample that received study materials and a subgroup analysis of study completers showed that children who played the shape game significantly improved their shape naming and matching skills relative to children who played the number game. Children who played the number game did not significantly improve their numerical skills relative to children who played the shape game. Mathematical talk during gameplay varied between families but was correlated over time within families. Caregivers’ and children’s talk about matching cards by shape or color predicted children’s learning from the shape game. The results suggest that despite receiving uniform instructions and materials, there was significant variability in children’s home math experiences that predicted their learning from the card game