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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Techno-economic analysis of retrofitting existing fuel stations with DC fast chargers along with solar PV and energy storage with load flow analysis

Ghosh, Nilanshu January 2020 (has links)
The increasing number of electric vehicles (EVs) in the transport sector has rendered the conventional fuel-based vehicles obsolete along with the fuel filling stations. With the growth in EVs, there has been an increase in the public charging infrastructure with fast charging equipment being used to charge the EVs in least possible time and also address the issue of ‘range anxiety’ among the EV owners. Many countries like South Korea and Germany has seen policies being implemented to install fast chargers for EVs in existing fuel filling stations. This study aims conduct a techno-economic feasibility to analyse the potential of implementing Electric Vehicle Supply Equipment (EVSE) with fast charging capacity into existing fuel filling stations. The potential of using solar photovoltaic system (PV) and battery storage systems (BESS) to reduce the load from the grid is also explored. Scenarios are developed considering different configurations of the EVSE, PV and BESS and an in-depth economic analysis is conducted to analyse the economic feasibility of the configurations. The impact on the electricity grid is also analysed in this thesis by conducting a load flow analysis on the CIGRE Low voltage network for Europe using Python.The proposed design enables selection of techno-economically feasible configurations of EVSE, BESS and PV. The results of the design are explained with the UK as a case study. It is observed that the configurations with 3 EVSE, BESS and 8 hours and the configuration with 3 EVSE, 1 BESS and 1 PV system for 8 hours of operation are economically viable. The proposed design shows that though the connection cost is the dominant factor affecting the feasibility, use of BESS with or without PV can reduce the connection cost by almost 90% depending on the number of BESS. Load flow analysis is conducted for the different configurations of EVSE, BESS and PV on the CIGRE LV network on Pandapower in Python. The results indicate that the existing network needs to be reinforced to facilitate the connection of EV fast chargers into the grid. Upgrading the network cables and increasing the slack voltage to a value of 1.05 or 1.1 Volts per unit, are the two strategies that have been suggested in this study to prevent any undervoltage that may occur as a result of connecting the EVSE to the electricity grid. The simulations conducted for the two strategies highlight that by implementing these strategies into the electricity grid network, the undervoltage issues in the transmission network can be mitigated. / Det ökande antalet elfordon inom transportsektorn har gjort de konventionella bränslebaserade fordonen föråldrade tillsammans med bränslepåfyllningsstationerna. Med ökningen av elbilar har det skett en ökning av den offentliga laddningsinfrastrukturen med snabbladdningsutrustning som används för att ladda elbilarna på åtminstone möjlig tid och också ta itu med frågan om ’range anxiety’ bland elägare. Många länder som Sydkorea och Tyskland har sett politik införas för att installera snabbladdare för elbilar i befintliga bensinstationer. Denna studie syftar till att genomföra en teknisk-ekonomisk genomförbarhet för att analysera potentialen för att implementera elfordonstillförselutrustning (EVSE) med snabb laddningskapacitet i befintliga bensinstationer. Potentialen med att använda solcellssystem (PV) och batterilagringssystem (BESS) för att minska belastningen från nätet undersöks också. Scenarier utvecklas med beaktande av olika konfigurationer av EVSE, PV och BESS och en djupgående ekonomisk analys genomförs för att analysera konfigurationernas ekonomiska genomförbarhet. Effekten på elnätet analyseras också i denna avhandling genom att genomföra en belastningsflödesanalys på CIGRE lågspänningsnät för Europa med Python.Den föreslagna designen möjliggör val av tekno-ekonomiskt genomförbara konfigurationer av EVSE, BESS och PV. Resultaten av designen förklaras med Storbritannien som en fallstudie. Det observeras att konfigurationerna med 3 EVSE, BESS och 8 timmar och konfigurationen med 3 EVSE, 1 BESS och 1 PV-system för 8 timmars drift är ekonomiskt lönsamma. Den föreslagna designen visar att även om anslutningskostnaden är den dominerande faktorn som påverkar genomförbarheten, kan användning av BESS med eller utan solceller minska anslutningskostnaden med nästan 90% beroende på antalet BESS. Lastflödesanalys utförs för de olika konfigurationerna av EVSE, BESS och PV på CIGRE LV-nätverket på Pandapower i Python. Resultaten visar att det befintliga nätverket måste förstärkas för att underlätta anslutningen av EV-snabbladdare till nätet. Uppgradering av nätverkskablarna och ökning av spänningen till 1,05 eller 1,1 volt per enhet är de två strategier som har föreslagits i denna studie för att förhindra underspänning som kan uppstå till följd av att EVSE ansluts till elnätet. Simuleringarna för de två strategierna lyfter fram att genom att implementera dessa strategier i elnätet kan underspänningsfrågorna i överföringsnätet mildras.
12

Orsakar lyxväskor fjärilar i magen? : Motiven bakom köpet av en lyxväska / Does designer handbags make us feel the butterflies? : The motivation behind the purchase of a designer handbag.

Tran, Shawn, Andersson, Anna January 2010 (has links)
En av de mest efterfrågade lyxvarorna på dagens marknad är lyxväskor, allt fler väljer attkomplettera sin outfit med denna accessoar. Förr i tiden hade handväskan en merfunktionell roll då den enbart användes för att bära tillhörigheter i. Idag har handväskanen helt annan roll då den framförallt återspeglar en bild av den person som äger väskan.Konsumenter kan med hjälp av denna produkt utge sig för att ha bättre ekonomiskaförutsättningar än vad de i själva verket har.Prognoser visar att efterfrågan på lyxväskor ökar trots att vi befinner oss mitt i vad sombeskrivs som en av de största ekonomiska kriserna i världshistorian. Den svenskamarknaden för lyxväskor växer sig allt större och några bland de främsta varumärkenasom återfinns på marknaden är Gucci, Louis Vuitton, Mulberry, Hermes etc.Eftersom vårt syfte är att undersöka vad motivationen är hos konsumenter som väljer attköpa lyxväskor har vi valt att genomföra en kvalitativ studie på tio personer, varför vivalde att genomföra en studie av kvalitativ karaktär var med anledning av att vi hadebehov av mycket information som berörde respondenterna på ett personligt plan.Respondenterna som vi har valt att genomföra denna studie på är alla unga kvinnor ochmän, större delen av de jobbar inom handel samt restaurangbranschen.Vi har funnit att respondenterna i denna undersökning inför köpet av sin lyxväska befannsig i ett spänningstillstånd orsakat av en konflikt mellan deras lustfyllda begär ochansvarskänsla kring deras ekonomiska situation. Resultatet påvisar att främstaanledningen till varför respondenterna köper lyxväskor är för att bli bekräftade av sinsociala omgivning. Behovet av konformitet är överordnat andra behov som exempelvisfunktionalitet. Status anses vara ett utav de viktigaste värdena som respondenterna kanerhålla igenom köpet av en lyxväska, exempelvis använder vissa av respondenternalyxväskan som en symbol för att öka sin status vid anställningsintervjuer.Utifrån det empiriska utfallet kunde vi se ett mönster där majoriteten av respondenternasom köper lyxväskor prioriterar sitt självförverkligande framför kvaliteten på mergrundläggande behov som till exempel mat och boende. Detta gör att vi funderar på omMaslows behovshierarki är användbar i sin nuvarande form i ett land med västerländskkultur.Respondenternas strävan samt önskan efter att erhålla de värden som köpet av enlyxväska innebär gör att de inte tar hänsyn till hållbarhetstrenden. Bland annat ser vi atten stor del av respondenterna köper lyxväskor som överstiger deras ekonomiskaförutsättningar.
13

Automatizace elektrických testů v automobilovém průmyslu

EGNER, Jakub January 2018 (has links)
Topic of diploma thesis "Automatization of electrical tests in automotive industry" is execution of the electrical tests in automotive industry. Common reasons for electrical tests and electrical tests according to customers norm LV 124 are described in this work. Automation application for controlling of the available equipment at laboratory of the department PS-SD/EPS-Bj of company Robert Bosch spol. s.r.o., which is necessary for execution of the electrical tests is designed and created in last section of this diploma thesis.
14

Role of BDNF in Cardiac Remodeling and Dysfunction in Rats After Myocardial Infarction

Lee, Heow Won 23 September 2019 (has links)
Myocardial infarction (MI) induced heart failure (HF) is a leading cause of morbidity and mortality over the world. Regular exercise improves quality of life and decreases hospitalization and mortality of patients with HF. In animals, exercise post MI attenuates progressive cardiac remodeling and cardiac dysfunction, and decreases neuronal activity in the paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM), which are key brain nuclei contributing to sympathetic hyperactivity post MI. The peripheral and central molecular mechanisms underlying these beneficial effects of exercise are not well understood. We studied one possible mechanism, brain-derived neurotrophic factor (BDNF), an exercise-induced factor, which via binding to its receptor tropomyosin-related kinase B (TrkB) may contribute to improvement of cardiac function post MI. In the brain, the ratio between two isoforms of the TrkB receptor, full-length and truncated forms (TrkB.FL/TrkB.T1) determines the extent of intracellular responses to mature BDNF (mBDNF; an active form of BDNF) and a decrease in this ratio may reflect down-regulation of BDNF-TrkB.FL signaling. Ca2+/calmodulin-dependent kinase II (CaMKII) and protein kinase B (Akt) are intracellular factors of BDNF-TrkB signaling in hippocampal/cortical neurons. Activation of cardiac BDNF-TrkB signaling may increase cardiomyocyte survival and myocardial contractility. In hypertensive rats, the role of BDNF-TrkB signaling in the PVN and RVLM appears opposite with activation of this axis in the PVN increasing, but in the RVLM decreasing sympathetic nerve activity (SNA). However, activation of CaMKII and Akt in the PVN and RVLM both mediate increase in SNA. The specific role of BDNF-TrkB signaling in the PVN and RVLM of rats with HF post MI has not yet been studied. We hypothesized that exercise training post MI enhances BDNF-TrkB signaling pathways in the left ventricle (LV) and RVLM, but inhibits in the PVN, and thereby preserves cardiac structure and function post MI. We evaluated changes in BDNF-TrkB axis and intracellular factors CaMKII and Akt in the non-infarct area of the LV, PVN and RVLM in sedentary and exercising rats with MI. The impact of systemic blockade of BDNF-TrkB signaling was assessed with ANA-12, a selective non-competitive antagonist of TrkB receptors. In the infarct area of the LV, mBDNF protein decreased and TrkB.T1 protein increased. In the non-infarct area, mBDNF tended to be decreased without change in TrkB.T1 expression. The activities of CaMKII and Akt were decreased in the non-infarct area of the LV. In the PVN and RVLM, the TrkB.FL/TrkB.T1 ratio was decreased but without changes in mBDNF and downstream factors except for decrease in Akt activity in the RVLM. Exercise training improved ejection fraction (EF), cardiac index and LV end-diastolic pressure, but only the exercise-induced improvement of EF was blocked by ANA-12. In the non-infarct area of the LV, exercise prevented decreases in mBDNF, CaMKII and Akt, and these effects were prevented by ANA-12. In the PVN, exercise increased mBDNF and decreased Akt activity, whereas in the RVLM, exercise had no effect on mBDNF but decreased CaMKII activity. The exercise-induced increase mBDNF in the PVN and decrease in p-CaMKIIβ expression in the RVLM were prevented by ANA-12. Our findings suggest that down-regulation of BDNF-TrkB signaling post MI is prominent in the LV with decreases in mBDNF protein in the infarct area and intracellular factors CaMKII and Akt in the non-infarct area. Increases in mBDNF, CaMKII and Akt in the LV by exercise may contribute to improvement of EF. In the PVN and RVLM, despite a decrease in the ratio of TrkB.FL/TrkB.T1 in both brain nuclei, only Akt activity decreased in the RVLM post MI. Exercise-induced decreases in activities of CaMKII in the RVLM and Akt in the PVN may both contribute to reduction in sympathetic hyperactivity post MI.
15

An investigation of the Morganroth hypothesis to establish if heart adaptation is exercise specific

Richards, Joanna C. January 2012 (has links)
The investigation of exercise specific left ventricular (LV) adaptations to training have been predominantly cross sectional in design. The purpose of the current thesis was to investigate LV adaptations to short term (6-9 weeks) training to establish if any changes are exercise specific. A correlation study was used to investigate correlations between cardiac variables and MAXOV2&(study 1). Cardiac variables were found to be the strongest predictors for absolute MAXOV2&, MAXOV2&BM and MAXOV2&FFM in cyclists compared to the total sample or sedentary group, predicting 79% (p<0.01), 70% (p<0.01) and 77% (p<0.01) of the variance, respectively. Secondly, it was found that when MAXOV2& was scaled to body mass (BM) or fat free mass (FFM) cardiac variables predicted less of the variance than for absolute MAXOV2&, for all groups. Study 2 investigated the hypothesis that there would be no evidence of LV hypertrophy when there was no increase in FFM. This was achieved by taking sedentary participants through a resistance training programme of 6 weeks duration to control for increases in skeletal muscle hypertrophy. Both resting systolic blood pressure (sBP; p = 0.01, d = 1.19) and diastolic blood pressure (dBP; p = 0.029, d = 0.88) were significantly reduced following the 6 weeks resistance training. One repetition maximum (1RM) bench press significantly increased (p = 0.00, d = -1.44) as did 1 RM parallel squat strength (p = 0.00, d = -1.86), with no associated increases in relative FFM (p = 0.45) or absolute LM (p = 0.87). There was no adaptation to LV morphology (p>0.05), however early diastolic function changed with a significant decrease in peak E wave (p = 0.00, d = 1.94). Study 3 compared differences in the time course of the initial adaptations to LV structure and function during 9 weeks of aerobic, resistance and combination exercise ii training, to establish whether LV adaptations are exercise specific. The resistance and combination groups demonstrated increases in relative wall thickness (p = 0.021, ηp2 = 0.408; p = 0.004, d = -1.06, respectively). PWd also significantly increased in the combination group (p = 0.032, ηp2 = 0.301); however there were no structural adaptations evident in the aerobic group (p > 0.05). In contrast, the aerobic group demonstrated functional adaptations with a decrease in A wave (p = 0.44, d = 0.87) as did the combination group (p = 0.002, ηp2 = 0.407). The results of the training studies showed limited support for the Morganroth Hypothesis as structural adaptations demonstrated LV remodelling of the myocardial tissue, with no increase in LV mass. Further to this, combination training appears to have an additive effect of LV adaptations of both aerobic and resistance training.
16

mRNA Levels of ERG, KVLQT1 and minK in Rabbit Right and Left Ventricles

LU, Zhibo, HOJO, Mayumi, YASUI, Kenji, KODAMA, Itsuo, KAMIYA, Kaichiro 12 1900 (has links)
国立情報学研究所で電子化したコンテンツを使用している。
17

Power electronics considerations for voltage regulation and VAR control approaches in LV distribution networks-hybrid power electronic modules

Radi, Mohammed A. M. January 2016 (has links)
The future substation depends on finding a way to mitigate the effects of the drawbacks of the conventional legacy by employing the efficiency of the solid state switches in light of changing the loading features by time such as Electrical Vehicles (EV) and Photo-voltaic (PV) cells. In distribution transformers the ratio between the primary voltage and the secondary voltage cannot be changed, and the use of the on-load taps changers are limited. Poor voltage regulation and reactive power transmission is a direct reason for losses and shortening the life of several devices. This research discusses the considerations of applying Power Electronics (PE) approaches and designs that provide additional functions in regulating the voltage and controlling the reactive power that is injected in the distribution network, using embedded fractional rated converters attached partially with the windings of the LV transformer. These approaches studies the possible considerations that have the potentials to enhance the unit with more flexibility in controlling the voltage and reactive power at the last mile of the network, in order to decrease the losses and meet the future expectations for low voltage networks modifications, and that by using a Power Electronic (PE) approach has less losses and more functionality depending on the reliability of transformer and intelligence of PE solutions. The approach of a hybrid distribution transformer is introduced and its functionality in regulating the voltage and injecting reactive power is illustrated. A back-to-back converter is controlled according to the immediate need for voltage control and reactive power in Low Voltage (LV) networks, and for the purpose of controlling three unbalanced phases using two control strategies; resonant controller and vector control. The overall controller adds or decreases voltage (10%-20%) to/from the total output voltage in order to control the whole output voltage of the transformer. In addition, some loads need high amount of reactive power at last mile of the network, therefore the consideration of using switched capacitors technique is introduced to serve at the end user side whereby its ability to provide automatic variable reactive power compensation in a closed loop system is illustrated. The considerations results indicate significant potentials for deploying PE in the last mile of the network by using innovative designs and suitable control functions with less losses and costs.
18

The Intricate Structure of HH 508, the Brightest Microjet in the Orion Nebula

Wu, Ya-Lin, Close, Laird M., Kim, Jinyoung Serena, Males, Jared R., Morzinski, Katie M. 21 February 2018 (has links)
We present Magellan adaptive optics Ha imaging of HH 508, which has the highest surface brightness among protostellar jets in the Orion Nebula. We find that HH 508 actually has a shorter component to the west, and a longer and knotty component to the east. The east component has a kink at 0.'' 3 from the jet-driving star theta(1) Ori B-2, so it may have been deflected by the wind/radiation from the nearby theta(1) Ori B1B5. The origin of both components is unclear, but if each of them is a separate jet, then theta(1) Ori B-2 may be a tight binary. Alternatively, HH 508 may be a slow-moving outflow, and each component represents an illuminated cavity wall. The ionization front surrounding theta(1) Ori B2B3 does not directly face theta(1) Ori B1B5, suggesting that the EUV radiation from theta(1) Ori C plays a dominant role in affecting the morphology of proplyds even in the vicinity of theta(1) Ori B1B5. Finally, we report an Ha blob that might be ejected by the binary proplyd LV 1.
19

Finite element modelling of LV transformer winding to simulate dynamic events occurring under short circuit : In Ansys Mechanical

Bikkina, Madhu Venkata Sri Prudhvi January 2020 (has links)
The ability to withstand a short circuit is the most essential feature of a power transformer. The most important reason to design short-circuits proof transformers is to ensure the reliability of the power grid (avoiding black outs etc.) and safety (fire and explosion in case of failure). During short circuit, the most effected winding is the LV winding due to the flow high currents even during the normal working condition. So during a short circuit large forces are generated which act on the winding and these forces can reach hundreds of tons in fraction of a second, so the transformer must be properly designed in order to withstand these forces or the transformer can fail in different ways. One of the possible failure modes called “Spiraling” is discussed and analyzed in this thesis. Spiraling Occurs when the LV winding twists tangentially in the opposite direction at the ends due to radial short circuit forces. From literature study the transient forces acting on the winding during a 3-phase short circuit was determined and these transient forces were used to perform simulations on the model. The axial and radial forces applied on the model were such that it has a uniform magnitude per each turn. Various analysis was performed on the model which includes the Static, Modal and Transient Structural analysis in Ansys Workbench and each analysis involved parametric analysis where the deformations and the torsional mode shapes were determined
20

How Effective Is a Late-Onset Antihypertensive Treatment?: Studies with Captopril as Monotherapy and in Combination with Nifedipine in Old Spontaneously Hypertensive Rats

Hawlitschek, Christina, Brendel, Julia, Gabriel, Philipp, Schierle, Katrin, Salameh, Aida, Zimmer, Heinz-Gerd, Rassler, Beate 27 February 2024 (has links)
Background: A major problem in the treatment of human hypertension is the late diagnosis of hypertension and, hence, the delayed start of treatment. Very often, hypertension has existed for a long time and cardiac damage has already developed. Therefore, we tested whether late- onset antihypertensive treatment is effective in lowering blood pressure (BP) and in reducing or even preventing left ventricular hypertrophy and fibrosis. Methods: Twenty-one male 60-week-old spontaneously hypertensive rats (SHR) were included. Fourteen rats received oral treatment with captopril (CAP) either as monotherapy or combined with nifedipine (CAP + NIF) over 22 weeks. Seven untreated SHR served as controls. We examined the therapeutic effects on BP, heart weight and histological and biochemical markers of left ventricular remodeling and fibrosis. Results: At 82 weeks of age, BP was reduced in the CAP and CAP + NIF groups by 44 and 51 mmHg, respectively (p < 0.001), but not in untreated controls. Despite the late therapy start, cardiac hypertrophy and fibrosis were attenuated compared to controls. Both treatments reduced heart weight by 1.2 mg/g (25%, p = 0.001) and collagens I and III by 66% and 60%, respectively (p < 0.001), thus proving nearly equivalent cardioprotective efficacy. Conclusion: These data clearly emphasize the benefit of antihypertensive treatment in reducing BP and mitigating the development of cardiac amage even when treatment is started late in life.

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