Energy Efficiency of Seasonal Solar Thermal Energy Storage System for Greenhouse Heating

Seasonal Thermal Energy Storage (STES) is widely researched for having benefits in that it utilizes excess energy which would be wasted otherwise. The purpose of this study is to analyze energy efficiency of seasonal solar thermal energy system as heating system for greenhouses and compare it with conventional variable air volume (VAV) heating system. Greenhouse was chosen as a simulation model because it requires constant and stable heating through winter season to extend growing season and also because greenhouse can provide enough area to install solar collectors and heat storage tanks. The proposed seasonal solar thermal energy storage system consists of solar thermal collector, fully mixed heat storage tank, and VAV system. Energy simulation was conducted in two steps: heat storing in summer season, and heating in winter season. For greenhouses with area sizing 1600 m2, solar thermal collector of 1250 m2 and heat storage tank of 2000 m3 were designed. TRNSYS 17 and engineering equation solver (EES) were implemented for simulation and calculation of the systems thermal data. Simulation results showed the tank water temperature rising up to optimal temperature (95 oC) before heating season, and STES heating contributed to 55% of total heating load. Consequently, 30% of total heating cost was cut down showing energy efficiency of seasonal solar thermal energy storage system

Spektroskopische Messungen im Anodenplasma einer fremdmagnetisch isolierten Hochleistungs-Ionendiode

Die Qualität der mit dem Protonenbeschleuniger KALIF erzeugten Ionenstrahlen hängt wesentlich von den Eigenschaften der Anoden- und Kathodenplasmen sowie von elektromagnetischen Fluktuationen in der Beschleunigungsstrecke ab. Eine Voraussetzung für die Verbesserung der Strahlqualität ist die genaue Kenntnis der Plasmaeigenschaften und der elektromagnetischen Feldverteilung im Beschleunigungsspalt. In dieser Arbeit wurden die Eigenschaften des Anodenplasmas untersucht. Elek-tronendichte und -Temperatur und die Zusammensetzung des Anodenplasmas wurden mit optischer Spektroskopie bestimmt. Die ermittelte Elektronendichte wuchs von 11016 cm-3 zu Beginn auf bis zu 51017cm-3 am Ende des KALIF-Impulses an. Die Elektronentemperatur erreichte sehr schnell Werte um 7 eV. Neben Wasserstoff befand sich überwiegend dreifach ionisierter Kohlenstoff im Anodenplasma. Die Wasserstoffdichte nahm kontinuierlich während des gesamten Impulses zu. Die Dynamik des Magnetfelds im Anodenplasma einer Hochleistungsionendiode konnte erstmals aus orts- und zeitaufgelösten Messungen der Zeemanaufspaltung von CIII und CIV-Linien ermittelt werden. Aus dem beobachteten Eindringen des durch die Elektronendrift im Diodenspalt induzierten diamagnetischen Feldes in die Anodenplasmaschicht ergeben sich wichtige Konzequenzen für das Be-triebsverhalten der Diode. Dazu gehören die Schwächung der magnetischen Isolation, was eine Abnahme der Diodenimpedanz im Laufe des Impulses und möglicherweise sogar einen Kollaps der virtuellen Kathode auf die Anode zur Folge hat. Noch bedeutendere Auswirkungen ergeben sich aus der induzierten Wirbelstromheizung der Anodenplasmaschicht, was zu einem exponentiellen Wachstum der Teilchendichte im Plasma führt. Ein weiteres Ziel der Arbeit war die Messung des Strahldivergenzwachstums im Beschleunigungsspalt der Diode. Die Strahldivergenz sollte aus der Doppler-verbreiterung von Spektrallinien geeigneter im Diodenspalt beschleunigter Ionen, z.B. Kohlenstoff, die als natürliche Kontaminanten im Anodenplasma vorhanden waren, ermittelt werden. Obwohl diese Kontaminanten in genügender Menge im Anodenplasma vorkamen, blieb ihre Intensität im Diodenspalt unterhalb der Nachweisgrenze. Als Ursache hierfür wird die Abschirmung des elektrischen Extraktionsfeldes für die Kohlenstoffionen durch eine dünne Protonenschicht an der Plasmafront angesehen. Eine Messung der Strahldivergenz direkt am Plasma-rand war jedoch möglich. Diese Ergebnisse zeigen, daß ein großer Teil der Strahldivergenz bereits am Rand des Anodenplasmas entsteht, was auf eine räumlich inhomogene Plasmaoberfläche hindeutet

Surgical repair of descending thoracic and thoracoabdominal aortic aneurysm involving the distal arch: Open proximal anastomosis under deep hypothermia versus arch clamping technique

BackgroundSurgical repair of a descending thoracic and thoracoabdominal aortic aneurysm (DTA/TAAA) involving the distal arch is challenging and requires either deep hypothermic circulatory arrest (DHCA) or crossclamping of the distal arch. The aim of this study was to compare these 2 techniques in the treatment of DTA/TAAA involving the distal arch.MethodsFrom 1994 to 2012, 298 patients underwent open repair of DTA/TAAA through a left thoracotomy. One hundred seventy-four patients with distal arch involvement who were suitable for either DHCA (n = 81) or arch clamping (AC; n = 93), were analyzed. In-hospital outcomes were compared using propensity scores and inverse-probability-of-treatment weighting adjustment to reduce treatment selection bias.ResultsEarly mortality was 11.1% in the DHCA group and 8.6% in the AC group (P = .58). Major adverse outcomes included stroke in 16 patients (9.2%), low cardiac output syndrome in 15 (8.6%), paraplegia in 10 (5.7%), and multiorgan failure in 10 (5.7%). After adjustment, patients who underwent DHCA were at similar risk of death (odds ratio [OR], 1.14; P = .80) and permanent neurologic injury (OR, 0.95; P = .92) to those who underwent AC. Although prolonged ventilator support (>24 hours) was more frequent with DHCA than with AC (OR, 2.60; P = .003), DHCA showed a tendency to lower the risk of paraplegia (OR, 0.15; P = .057).ConclusionsCompared with AC, DHCA did not increase postoperative mortality and morbidity, except for prolonged ventilator support. However, DHCA may offer superior spinal cord protection to AC during repair of DTA/TAAA involving the distal arch

Novel a‐Si:H TFT pixel circuit for electrically stable top‐anode light‐emitting AMOLEDs

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92120/1/1.2770853.pd

The Structural Quality of AlxGa1-xN Epitaxial Layers Grown by Digitally-AlloyedModulated Precursor Epitaxy Determined by Transmission Electron Microscopy

Al(x)Ga(1-x)N layers of varying composition (0.5<x(Al)<1.0) grown in the digitally-alloyed modulated precursor epitaxial regime employing AlN and GaN binary sub-layers by metalorganic chemical vapor deposition on AlN templates were characterized by transmission electron microscopy techniques. Fine lamellae were observed in bright field images that indicate a possible variation in composition due to the modulated nature of growth. In higher Ga content samples (x(Al)<0.75), a compositional inhomogeniety associated with thicker island regions was observed, which is determined to be due to large Ga-rich areas formed at the base of the layer. Possible causes for the separation of Ga-rich material are discussed in the context of the growth regime used

Estrogen receptor-α gene haplotype is associated with primary knee osteoarthritis in Korean population

Estrogen and estrogen receptors (ERs) are known to play important roles in the pathophysiology of osteoarthritis (OA). To investigate ER-α gene polymorphisms for its associations with primary knee OA, we conducted a case–control association study in patients with primary knee OA (n = 151) and healthy individuals (n = 397) in the Korean population. Haplotyping analysis was used to determine the relationship between three polymorphisms in the ER-α gene (intron 1 T/C, intron 1 A/G and exon 8 G/A) and primary knee OA. Genotypes of the ER-α gene polymorphism were determined by PCR followed by restriction enzyme digestion (PvuII for intron 1 T/C, XbaI for intron 1 A/G, and BtgI for exon 8 G/A polymorphism). There was no significant difference between primary knee OA patients and healthy control individuals in the distribution of any of the genotypes evaluated. However, we found that the allele frequency for the exon 8 G/A BtgI polymorphism (codon 594) was significantly different between primary knee OA patients and control individuals (odds ratio = 1.38, 95% confidence interval = 1.01–1.88; P = 0.044). In haplotype frequency estimation analysis, there was a significant difference between primary knee OA patients and control individuals (degrees of freedom = 7, χ(2 )= 21.48; P = 0.003). Although the number OA patients studied is small, the present study shows that ER-α gene haplotype may be associated with primary knee OA, and genetic variations in the ER-α gene may be involved in OA