Transient combustion modeling of an oscillating lean premixed methane/air flame

The main objective of the present study is to demonstrate accurate low frequency transient turbulent combustion modeling. For accurate flame dynamics some improvements were made to the standard TFC combustion model for lean premixed combustion. With use of a 1D laminar flamelet code, predictions have been made for the laminar flame speed and the critical strain rate to improve the TFC (Turbulent Flame Speed Closure) combustion model. The computational fluid dynamics program CFX is used to perform transient simulations. These results were compared with experimental data of Weigand et al [1]. Two different\ud turbulence models have been used for predictions of the turbulent flow

Verhoging van de N-benutting uit drijfmest bij lelie

De totale N-gift bij lelieteelt is in Zuidoost Nederland gemiddeld aanzienlijk hoger dan de N-norm. Dit is vermoedelijk te verklaren door een slechte benutting van de stikstof uit drijfmest. Deze lijkt soms verloren te gaan door de toedieningswijze (onderploegen, waardoor de mest ten dele in de ondiepe wortelzone terecht komt) en soms door uitspoeling met intensieve beregening. In dit project werd onderzocht of het injecteren van varkensdrijfmest in de bovenste 10 cm in plaats van het onder te ploegen de N-benutting uit drijfmest verbetert, waardoor tijdens de teelt minder stikstof bemest hoeft te worden

Modal decomposition of a propagating matter wave via electron ptychography

We employ ptychography, a phase-retrieval imaging technique, to show experimentally for the first time that a partially coherent high-energy matter (electron) wave emanating from an extended source can be decomposed into a set of mutually independent modes of minimal rank. Partial coherence significantly determines the optical transfer properties of an electron microscope and so there has been much work on this subject. However, previous studies have employed forms of interferometry to determine spatial coherence between discrete points in the wavefield. Here we use the density matrix to derive a formal quantum mechanical description of electron ptychography and use it to measure a full description of the spatial coherence of a propagating matter wavefield, at least to the within the fundamental uncertainties of the measurements we can obtain

Stikstofbijmestsysteem voldoet aan N-behoefte lelie en gladiool

De aanleiding tot dit onderzoek was het van kracht worden van de N-gebruiksnormen voor landbouwgewassen in 2006 die volgens telers van lelie en gladiool en voorlichters te laag is voor een optimale teelt. In de belangrijkste teeltgebieden van lelie en gladiool, nl. de Noordoostpolder (NOP), Noordoost-Nederland (NON) en Zuidoost-Nederland (ZON) zou de N-behoefte van lelie en gladiool voor een optimaal teelt- en afbroeiresultaat hoger zijn dan de gebruiksnorm

Gastrointestinal Symptoms in Infants of Mothers with a Psychiatric History and the Role of Depression and Bonding

Objectives: Gastroesophageal reflux (GER), excessive crying, and constipation are common gastrointestinal symptoms in infancy of multifactorial origin in which psychosocial stress factors play an important role. The aims of this observational study were to investigate the presence of gastrointestinal symptoms in infants of mothers with or without a history of a psychiatric disorder, their association with maternal depressive symptoms, and the possible mediating role of bonding. Methods: 101 mothers with a history of a psychiatric disorder (“PD mothers”) and 60 control mothers were included. Infant gastrointestinal symptoms, maternal depressive symptoms, and mother-infant bonding were assessed using validated questionnaires and diagnostic criteria at 1.5 month postpartum. Results: The mean total score on the Infant Gastroesophageal Reflux Questionnaire Revised (I-GERQ-R) reported in infants of PD mothers (13.4 SD 5.4) was significantly higher than in infants of control mothers (10.8 SD 5.4; P =.003). No significant differences were found in the presence of excessive crying (modified Wessel’s criteria and subjective experience) and constipation (ROME IV criteria) between both groups. Infant GER was associated with maternal depressive symptoms (P = 0.027) and bonding problems (P = <0.001). Constipation was related to maternal depressive symptoms (P = 0.045), and excessive crying (Wessel and subjective criteria) was associated with bonding problems (respectively P = 0.022 and P = 0.002). The effect of maternal depressive symptomatology on infant GER symptoms and excessive crying was mediated by bonding problems. Conclusion: Maternal psychiatric history is associated with infant gastrointestinal symptoms, in which mother-infant bonding is a mediating factor

Model-based cap thickness and peak cap stress prediction for carotid MRI

A rupture-prone carotid plaque can potentially be identified by calculating the peak cap stress (PCS). For these calculations, plaque geometry from MRI is often used. Unfortunately, MRI is hampered by a low resolution, leading to an overestimation of cap thickness and an underestimation of PCS. We developed a model to reconstruct the cap based on plaque geometry to better predict cap thickness and PCS. We used histological stained plaques from 34 patients. These plaques were segmented and served as the ground truth. Sections of these plaques contained 93 necrotic cores with a cap thickness <0.62 mm which were used to generate a geometry-based model. The histological data was used to simulate in vivo MRI images, which were manually delineated by three experienced MRI readers. Caps below the MRI resolution (n = 31) were (digitally removed and) reconstructed according to the geometry-based model. Cap thickness and PCS were determined for the ground truth, readers, and reconstructed geometries. Cap thickness was 0.07 mm for the ground truth, 0.23 mm for the readers, and 0.12 mm for the reconstructed geometries. The model predicts cap thickness significantly better than the readers. PCS was 464 kPa for the ground truth, 262 kPa for the readers and 384 kPa for the reconstructed geometries. The model did not predict the PCS significantly better than the readers. The geometry-based model provided a significant improvement for cap thickness estimation and can potentially help in rupture-risk prediction, solely based on cap thickness. Estimation of PCS estimation did not improve, probably due to the complex shape of the plaques