Lean body weight-tailored Iodinated contrast Injection in obese patient. boer versus James Formula

Purpose. To prospectively compare the performance of James and Boer formula in contrast media (CM) administration, in terms of image quality and parenchymal enhancement in obese patients undergoing CT of the abdomen. Materials and Methods. Fifty-five patients with a body mass index (BMI) greater than 35 kg/m2were prospectively included in the study. All patients underwent 64-row CT examination and were randomly divided in two groups: 26 patients in Group A and 29 patients in Group B. The amount of injected CM was computed according to the patient's lean body weight (LBW), estimated using either Boer formula (Group A) or James formula (Group B). Patient's characteristics, CM volume, contrast-to-noise ratio (CNR) of liver, aorta and portal vein, and liver contrast enhancement index (CEI) were compared between the two groups. For subjective image analysis readers were asked to rate the enhancement of liver, kidneys, and pancreas based on a 5-point Likert scale. Results. Liver CNR, aortic CNR, and portal vein CNR showed no significant difference between Group A and Group B (all P ≥ 0.177). Group A provided significantly higher CEI compared to Group B (P = 0.007). Group A and Group B returned comparable overall subjective enhancement values (3.54 and vs 3.20, all P ≥ 0.199). Conclusions. Boer formula should be the method of choice for LBW estimation in obese patients, leading to an accurate CM amount calculation and an optimal liver contrast enhancement in CT

Progettazione e realizzazione di uno stampo allo stato dell’arte

2nonenoneA. PANVINI; A. POLAPanvini, Andrea; Pola, Annalis

OPTIMIZATION OF DIE VENTING DESIGN THROUGH ANALYTICAL CALCULATIONS

Air entrapment during diecasting die filling is a major problem that causes most rejects, after quality inspection, due to unattended and dangerous gas porosity, especially in high performance and structural parts. In the past years, many technologies were developed in order to reduce air entrapment during filling; among them, optimal results were mainly obtained by active (vacuum) and passive (chill vents) air evacuation systems. Nevertheless, only small knowledge on how to optimize dies design for those technologies is available for the die maker. In the same way, at now, many casting simulation software lacks in this specific field and today ventings, vacuum channels and chill vents are designed according to proprietary formulas and, mainly, experience. In order to understand what happens to air inside a die cavity before and during metal injection, an analytical model was developed to calculate and forecast air pressure and flow through vents. This model takes into account, in a very detailed way, all the phenomena that occurs during injection, with particular relevance to process parameters (injection speeds and strokes, temperatures, vacuum pressures…) as well as flow-related phenomena that can impact on air escape, like premature vents clogging. This mathematical model was then validated and optimized through extensive casting trials in different venting simulation (with vacuum, only vents, chill vents, no air escape…) on different casting shapes and with different process parameters. The model allows to the die designer to optimize vents and related operating process parameters, simulate and compare different air evacuation solutions and forecast the mean gas porosity fraction in the casting with a calculation time of only few seconds. Calculations were useful to demonstrate the influence of process parameters on air trapping and the main result was that venting (with or without vacuum) is ineffective without an optimal setup of casting parameters and a correct air escape area calculation

Cradle-to-Gate Impact Assessment of a High-Pressure Die-Casting Safety-Relevant Automotive Component

The mass of automotive components has a direct influence on several aspects of vehicle performance, including both fuel consumption and tailpipe emissions, but the real environmental benefit has to be evaluated considering the entire life of the products with a proper Life Cycle Assessment (LCA). In this context, the present paper analyzes the environmental burden connected to the production of a safety relevant aluminum high pressure die casting component for commercial vehicles (a suspension cross beam) considering all the phases connected to its manufacture. The focus on aluminum high-pressure die casting reflects the current trend of the industry and its high energy consumption. This work shows a new method that deeply analyzes every single step of the component's production through the implementation of a wide database of primary data collected thanks to collaborations of some automotive supplier companies. This energy analysis shows significant environmental benefits of the aluminum recycling