28 research outputs found

    HD-TEG: Effizienzsteigerungspotential bei Nutzfahrzeugen durch den Einsatz eines neuartigen Abwärmenutzungssystems (Thermoelektrik)

    Get PDF
    In diesem Projekt wurde die Effizienzsteigerung von modernen schweren Nutzfahrzeugen durch den Einsatz eines neuartigen Abwärmenutzungssystems demonstriert. Dabei wurde erstmalig ein nutzfahrzeugspezifisches System basierend auf der Thermoelektrik mit Hilfe eines gesamtheitlichen Entwicklungsansatzes entwickelt und das Potential dieser Technologie für heutige und zukünftige Nutzfahrzeuge dargestellt. Als Referenzfahrzeug diente ein innovatives Serien-Nutzfahrzeug mit Erdgasmotor, welches als eine Schlüsseltechnologie für den zukünftigen emissionsärmeren Straßengüterverkehr im Nah- sowie im Fernbereich gilt. Projektschwerpunkte waren gleichermaßen die Effizienzsteigerung des thermoelektrischen Systems und des Fahrzeuges sowie die Kostensenkung des Systems durch Verwendung von seriennahen Aufbautechnologien und Fertigungsverfahren. Die Systemkosten von Abwärmenutzungssystemen im Nutzfahrzeug müssen sich anwendungsspezifisch in möglichst kurzer Nutzungszeit im Realbetrieb amortisieren. Dazu wurde eine Bauweise des TEG gewählt, die eine hohe Energieausbeute bei gleichzeitig geringem Gewicht verspricht und somit Vorteile sowohl unter Realfahrbedingungen als auch in relevanten Fahrzyklen bietet. Eine neuartige ganzheitliche Auslegungsmethode bietet das Potential, thermoelektrische Systeme in Zukunft deutlich effizienter auslegen zu können. Hierbei wurden neben der Systemauslegung erstmals auch alle Wechselwirkungen mit dem Nutzfahrzeug betrachtet und quantifiziert. Die Umsetzung dieser Ansätze wurden in mehreren Funktionsmustern dargestellt. Durch die enge Zusammenarbeit der Projektpartner, konnte das Wissen und die umfangreiche Erfahrung beider in das Projekt einfließen, um der Technologie im Nutzfahrzeug zum Durchbruch zu verhelfen. Als Ergebnis konnte erstmalig ein Abwärmenutzungssystem in Form eines Thermoelektrischen Generators für ein innovatives Erdgasnutzfahrzeug wirtschaftlich ausgelegt werden. Die berechnete Amortisation wurde zumeist in einer Zeit von kleiner als zwei Jahren, unter Annahme der Serienentwicklung des Systems, erzielt. Die Kraftstoffreduktion liegt bei bis zu 2,5 %, das entspricht rund 1 kg/100 km Kraftstoff. Zukünftiges Potential liegt bei weiteren 1,2 Prozentpunkten. Bei einer Hardwarerealisierung wurde am Funktionsmuster über 2,5 kW elektrische Leistung gemessen

    Homer1a Attenuates Endoplasmic Reticulum Stress-Induced Mitochondrial Stress After Ischemic Reperfusion Injury by Inhibiting the PERK Pathway

    Get PDF
    Homer1a is the short form of a scaffold protein that plays a protective role in many forms of stress. However, the role of Homer1a in cerebral ischemia/reperfusion (I/R) injury and its potential mechanism is still unknown. In this study, we found that Homer1a was upregulated by oxygen and glucose deprivation (OGD) and that overexpression of Homer1a alleviated OGD-induced lactate dehydrogenase (LDH) release and cell death in cultured cortical neurons. After OGD treatment, the overexpression of Homer1a preserved mitochondrial function, as evidenced by less cytochrome c release, less reactive oxygen species (ROS) production, less ATP and mitochondrial membrane potential (MMP) loss, less caspase-9 activation, and inhibition of endoplasmic reticulum (ER) stress confirmed by the decreased expression of phosphate-PKR-like ER Kinase (p-PERK)/PERK and phosphate- inositol-requiring enzyme 1 (p-IRE1)/IRE1 and immunofluorescence (IF) staining. In addition, mitochondrial protection of Homer1a was blocked by the ER stress activator Tunicamycin (TM) with a re-escalated ROS level, increasing ATP and MMP loss. Furthermore, Homer1a overexpression-induced mitochondrial stress attenuation was significantly reversed by activating the PERK pathway with TM and p-IRE1 inhibitor 3,5-dibromosalicylaldehyde (DBSA), as evidenced by increased cytochrome c release, increased ATP loss and a higher ROS level. However, activating the IRE1 pathway with TM and p-PERK inhibitor GSK2656157 showed little change in cytochrome c release and exhibited a moderate upgrade of ATP loss and ROS production in neurons. In summary, these findings demonstrated that Homer1a protects against OGD-induced injury by preserving mitochondrial function through inhibiting the PERK pathway. Our finding may reveal a promising target of protecting neurons from cerebral I/R injury

    Improved Financial Predicting Method Based on Time Series Long Short-Term Memory Algorithm

    No full text
    With developments in global economic integration and the increase in future economic uncertainty, it is imperative to have the ability to predict future capital in relation to financial capital inflow and outflow predictions to ensure capital optimization is within a controllable range within the current macroeconomic environment and situation. This paper proposes an automated capital prediction strategy for the capital supply chain using time series analysis artificial intelligence methods. Firstly, to analyze the fluctuation and tail risk of the financial characteristics, the paper explores the financial characteristics for measuring the dynamic VaR from the perspectives of volatility, tail, and peak with the Bayesian peaks over threshold (POT) model. Following this, in order to make the modeling more refined, the forecast targets are split before modeling with seasonal Autoregressive Integrated Moving Average (ARIMA) models and Prophet models. Finally, the time series modeling of the wavelet Long Short-Term Memory (LSTM) model is carried out using a two-part analysis method to determine the linear separated wavelet and non-linear embedded wavelet parts to predict strong volatility in financial capital. Taking the user capital flow of the Yu’e Bao platform, the results prove the feasibility and prediction accuracy of the innovative model proposed

    Secondary ocular hypertension due to tentorial dural arteriovenous fistula: a case report

    No full text
    Abstract Background Tentorial dural arteriovenous fistulas (TDAVFs) are abnormal shunts between meningeal arteries and the intradural venous system located in the tentorial dura mater, which typically manifest with haemorrhage or progressive neurological disorders. TDAVFs with pure ocular presentation have been rarely reported. Case Presentations The case of a 56-year-old man presented with unilateral eye redness, proptosis and elevated intraocular pressure was reported herein, which was caused by a TDAVF. The fistula was fed by the left posterior cerebral artery and posterior meningeal artery. The drainage was into the basal vein and internal cerebral veins, which led the arterial blood flow forward to the left superior ophthalmic vein directly. The redundant blood flow caused the rise of episcleral venous pressure, leading to the clinical presentations. Gamma knife radiosurgery was performed then considering the delicate vascular structure and its deep location. The corkscrew hyperaemia was gradually alleviated after the surgery, but the intraocular pressure remained elevated at follow-ups. Conclusion Dural arteriovenous fistulas which are not directly connected to cavernous sinus could cause ocular presentations like proptosis, eye redness and ocular hypertension

    Gandouling Mitigates CuSO4-Induced Heart Injury in Rats

    No full text
    We assessed the protective effects of Gandouling (GDL) on copper sulfate (CuSO4)-induced heart injuries in Sprague–Dawley rats, which were randomly divided into the control, CuSO4, GDL + CuSO4 and penicillamine + CuSO4 groups. The rats received intragastric GDL (400 mg/kg body weight) once per day for 42 consecutive days after 56 days of CuSO4 exposure, and penicillamine was used as a positive control. The levels of plasma inflammatory cytokines (IMA, hFABP, cTn-I and BNP) were determined using the enzyme-linked immunosorbent assay. The histopathological symptoms were evaluated using hematoxylin and eosin staining and transmission electron microscopy. To determine the underlying mechanism, Western blotting was conducted for the detection of the heme oxygenase 1 (HO-1) expression. The results revealed that GDL supplementation alleviated the histopathological symptoms of the rat heart tissue, promoted Cu excretion to attenuate impairment, and significantly decreased inflammatory cytokine levels in the plasma (p < 0.01). In addition, GDL increased the HO-1 expression in the rat hepatic tissue. The protective effect of GDL on the heart was superior to that of penicillamine. Overall, these findings indicate that GDL alleviates hepatic heart injury after a Cu overaccumulation challenge, and GDL supplements can be beneficial for patients with Wilson’s disease

    Effects of a Thermoelectric Waste Heat Recovery System on the Engine Performance and the Cooling System of a Natural Gas Powered Heavy-Duty Vehicle

    No full text
    The European Commission proposes to reduce CO2-emissions from heavy-duty vehicles by 35% by 2030 compared to 2019. Several technological approaches are required to achieve this ambitious goal. While electrification of short-distance distribution transport seems possible during this period, internal combustion engines continue to dominate long-distance freight transport and must therefore be further developed in terms of their efficiency and emissions. In this context, the market for low-emission natural gas-powered engines is growing. Although these engines produce less CO2-emissions, they are still unable to comply with the upcoming regulations, so that further measures such as waste heat recovery systems are necessary. One technology for this purpose is the thermoelectric generator. It is based on a solid state effect, the so-called Seebeck effect, and uses heat exchangers to convert the heat flow from the exhaust gas to the cooling system directly into electricity using semiconductor materials. In addition to the positive effect of the converted electrical power, negative effects influence the overall system. In particular, the additional pressure loss through the heat exchanger in the exhaust system and the heat transfer to the cooling system are decisive influencing factors. As an example, the additional pressure drop in the exhaust system must be overcome by the engine and reduces its efficiency. The additional heat input into the cooling system causes the cooling fan to be switched on earlier, which leads to a higher electrical consumption. This study aims to quantify these negative effects of waste heat recovery systems, in particular thermoelectric generators, on the overall vehicle system of natural gas powered heavy-duty vehicles. For this purpose, a one-dimensional model of a diesel engine is modified in order to adapt it to a natural gas engine. The CURSOR 13 NG engine serves as a reference. The modifications include the combustion model, the engine control, the turbocharger, the exhaust aftertreatment system and the cooling system. The influences of the thermoelectric generator are simulated for the operating points of the World Harmonized Stationary Cycle. For the pressure drop, various throttle valves are inserted into the exhaust system and the reactions of the engine are simulated. A heat exchanger is modelled for the cooling system, which transfers the heat either to the high or low temperature cooling circuit. The cooling capacity of the radiator is based on the vehicle speed of the World Harmonized Transient Cycle under suitable conditions. The results are summarized for both variables into characteristic maps. The efficiency of the motor decreases almost linearly with the pressure drop and is strongly dependent on the current operating point. At high loads, the pressure drop has a proportionally lower influence on the efficiency of the motor. The remaining capacity of the cooling system depends on the cooling circuit used, the maximum permissible coolant temperature and the vehicle speed. It ranges from around 40 kW to 120 kW. Both data sets show a high potential for the integration of a thermoelectric generator and are used for the further development and optimization of the system. Keywords: Thermoelectric Generator, Heavy-duty Vehicle, Waste Heat Recovery Syste

    Environmental Microvibration Analysis Method for Vibration Isolation Research in High-Precision Laboratories

    No full text
    Environmental microvibrations, often originating from unidentified sources, pose a significant challenge for predicting and controlling their complex wave fields, potentially leading to measurement errors of sensitive instruments in high-precision laboratories and impacting the accuracy of experimental outcomes. Therefore, investigating effective control measures for environmental microvibrations under passive conditions is key to addressing such engineering issues. This paper presents a finite element analysis method tailored to address environmental microvibrations in the absence of apparent sources. This method involves obtaining the vibration time history at specific ground surface points through field measurements and combining the Rayleigh wave velocity attenuation character with depth at the center frequencies of one-third octave bands within the 1–100 Hz frequency range; the vibration time history at any depth in the soil is calculated. These calculated vibrations are then applied as input loads to the corresponding nodes on one boundary of the foundation–soil model, serving as the source of environmental microvibrations. The predicted results are compared with measured data and the empirical point source input method, indicating that this approach is more precise and efficient, providing valuable reference for the prediction and analysis of environmental microvibrations. In addition, utilizing this method, the study examines the effects of pile foundation parameters such as the pile length, burial depth, and concrete baseplate thickness on the vibration isolation performance of environmental microvibrations, providing guidance for designing pile foundation isolation

    Anterior Segment Parameter Changes after Cataract Surgery in Open-Angle and Angle-Closure Eyes: A Prospective Study

    No full text
    Background: To investigate the anterior segment parameters before and after cataract surgery in open-angle eyes and different subtypes of primary angle-closure glaucoma (PACG) eyes and to further explore the potential relationship between the anterior rotation of the ciliary process and crystalline lens. Methods: An observational, prospective study was performed on 66 patients who had cataract surgery including 22 chronic PACG patients, 22 acute PACG patients, and 22 open-angle cataract patients. Anterior segment parameters including the trabecular-ciliary process distance, ciliary process area, trabecular-ciliary angle (TCA), maximum ciliary body thickness (CBTmax), and so on, were measured using ultrasound biomicroscopy preoperatively and 3 months postoperatively. Results: After the surgery, there were significant increases in TCA (p p p > 0.05) in all three groups. No significant difference in the changes of ciliary process area, TCA, and CBTmax (p > 0.05) pre- and postoperatively among the three groups were identified. Conclusions: Extractions of crystalline lenses played similar roles in terms of decreasing the anterior rotation of ciliary processes in open-angle eyes and angle-closure eyes. A natural anatomical abnormality may be a more important factor in the anterior rotation of ciliary processes in PACG patients
    corecore