Properties of the power conditioning system with a five-level cascaded converter and supercapacitor energy storage

The paper presents the power conditioning system (PCS) with a five-level cascaded H-bridge converter and supercapacitor energy storage. The paper focuses on such properties of a power electronic converter as its operation, power losses, start-up as well as the DC-link voltage balancing method and controller. A laboratory model of the PCS and its test results have been presented

Early parenteral nutrition and growth outcomes in preterm infants:a systematic review and meta-analysis

Background: The achievement of adequate nutritional intakes in preterm infants is challenging and may explain the poor growth often seen in this group. The use of early parenteral nutrition (PN) is one potential strategy to address this problem, although the benefits and harms are unknown. Objective: We determined whether earlier administration of PN benefits growth outcomes in preterm infants. Design: We conducted a systematic review of randomized controlled trials (RCTs) and observational studies. Results: Eight RCTs and 13 observational studies met the inclusion criteria (n = 553 and 1796 infants). The meta-analysis was limited by disparate growth-outcome measures. An assessment of bias was difficult because of inadequate reporting. Results are given as mean differences (95% CIs). Early PN reduced the time to regain birth weight by 2.2 d (1.1, 3.2 d) for RCTs and 3.2 d (2.0, 4.4 d) in observational studies. The maximum percentage weight loss with early PN was lower by 3.1 percentage points (1.7, 4.5 percentage points) for RCTs and by 3.5 percentage points (2.6, 4.3 percentage points) for observational studies. Early PN improved weight at discharge or 36 wk postmenstrual age by 14.9 g (5.3, 24.5 g) (observational studies only), but no benefit was shown for length or head circumference. There was no evidence that early PN significantly affects risk of mortality, necrotizing enterocolitis, sepsis, chronic lung disease, intraventricular hemorrhage, or cholestasis. Conclusions: The results of this review, although subject to some limitations, show that early PN provides a benefit for some shortterm growth outcomes. No evidence that early PN increases morbidity or mortality was found. Neonatal research would benefit from the development of a set of core growth outcome measures.</p

UMD Clark Engineering WIE Science and Technology Policy Papers

Science and Technology Policy Papers produced by students enrolled in the Women in Engineering program Flexus/Virtus living learning community for women, men, and non-binary engineering students