Operating cost comparison of a single-stack and a multi-stack hybrid fuel cell vehicle through an online hierarchical strategy

One of the recently suggested solutions for enhancing the fuel economy and lifetime in a fuel cell (FC) hybrid electric vehicle (HEV) is the use of a multi-stack (MS) structure for the FC system. However, to fully realize the potential of this structure, the design of an appropriate energy management strategy (EMS) is necessary. This paper aims to compare the operating cost, including hydrogen consumption and degradation of the FC, between a single-stack (SS) and an MSFC-HEV. To do so, a hierarchical EMS, composed of two layers, is devised for the MS system. In the first layer, a rule-based strategy determines how many FCs should be ON according to the requested power, battery state of charge (SOC), and FCs degradations. In the second layer, an equivalent consumption minimization strategy (ECMS) is developed to determine the output power of each activated FC according to the cost function and constraints. Regarding the SS structure, ECMS is employed for power distribution. The purpose of this strategy is to decrease fuel consumption and FC system degradation costs in both structures. The performance of the ECMS is compared with dynamic programming (DP) as a global optimization strategy for validation purposes. The obtained results using experimental data show that an FC-HEV with an MS structure reaches less hydrogen and degradation costs than an SS one

Adaptive parameter identification of a fuel cell system for health-conscious energy management applications

Since a proton exchange membrane (PEM) fuel cell (FC) has time-varying characteristics, its online characteristics estimation (voltage, power, internal resistance, etc.) is becoming a key step in designing an energy management strategy (EMS) for hybrid FC vehicles. In this respect, this paper proposes a new method based on Lyapunov adaptation law to estimate the linear and nonlinear parameters of a renowned PEMFC model in the literature. Unlike most of similar estimators, the suggested approach determines the maximum current, which is a nonlinear parameter, online while guaranteeing the system closed-loop stability. This parameter is normally assumed to be constant while it changes through time owing to degradation and operating conditions variation. This alteration makes the model imprecise while extracting some important characteristics, such as maximum power and polarization curve. Therefore, it needs to be regularly updated along with other parameters. To demonstrate the capability of the suggested method, a detailed comparison is provided with the well-known extended Kalman filter (EKF) as an attested nonlinear estimator. Moreover, to highlight the effectiveness of the nonlinearity consideration, a comparison with KF is performed where the nonlinear parameter is considered constant. The performed experiments on a 500-W PEMFC show that the proposed method can be over twice as accurate as EKF and KF concerning the estimation of maximum power and current while its runtime is nearly half of them

Transport Phenomena and Structuring in Shear Flow of Suspensions near Solid Walls

In this paper we apply the lattice-Boltzmann method and an extension to particle suspensions as introduced by Ladd et al. to study transport phenomena and structuring effects of particles suspended in a fluid near sheared solid walls. We find that a particle free region arises near walls, which has a width depending on the shear rate and the particle concentration. The wall causes the formation of parallel particle layers at low concentrations, where the number of particles per layer decreases with increasing distance to the wall.Comment: 14 pages, 14 figure

Inspædia: [Almost] Everything About Simplicity, Playfulness and Inspiration

The aim of this paper is to disclose the new research developments and the results from the systematization of experience and user interaction with the Inspædia (a new web knowledge “Agora”), to inspire a dynamic, collaborative, and interactive intelligence among the inspædiers. We will explain in detail and describe the design process and discuss the ultimate design interaction concept & development regarding (almost everything about) simplicity and playfulness of the inspædiers’ experience to transform relevant information (related > meanfull > useful) in productive knowledge (inspiration > insight > foresight) in a very easy and quick way (usability: learnability; understandability; operability; attractiveness...), with a smile in the face (satisfaction) and a wow in the mind (or in the soul).Inspædia is the natural consequence and development of the prototype resulting from the research in Design PhD thesis Innovation, design et cetera (FA/UTL, 2012). Therefore, it is being developed with the Science Without Borders Program (2013-2016) with a Special Visiting Researcher fellowship grant of CAPES (Brazil), and under the post-doctoral in Design at the Faculty of Architecture, University of Lisbon (FA/UL); CIAUD – Reseach Centre of Architecture, Urbanism and Design (FA/UL); Faculty of Sciences and Technology, Nova University of Lisbon (FCT/UNL); NOVA-LINCS (FCT/UNL) and CITAD - Research Centre for Territory, Architecture and Design (FAA/ULL). The Inspædia research project was ranked in first place in Design scientific area and obtained a post-doctoral fellowship by FCT – Foundation for Science and Technology (Portugal). The project has been internationally disseminated at international Design conferences with indexed publications. It was presented and published both at AHFE 2014 (Krakow) and AHFE 2015 (Las Vegas). It was part of the biennial Experimentadesign tangential events in 2013 (EXD'13), 2015 (EXD'15) and was presented, by invitation, at the International Congress DESIGN I-CON (2015). During the last year we prototyped and tested (usability testing) with some inspædiers different approaches to achieve users’ needs > desires > expectations) in a challenging way, in order to provide the most powerful and memorable user experience

The KATRIN Pre-Spectrometer at reduced Filter Energy

The KArlsruhe TRItium Neutrino experiment, KATRIN, will determine the mass of the electron neutrino with a sensitivity of 0.2 eV (90% C.L.) via a measurement of the beta-spectrum of gaseous tritium near its endpoint of E_0 =18.57 keV. An ultra-low background of about b = 10 mHz is among the requirements to reach this sensitivity. In the KATRIN main beam-line two spectrometers of MAC-E filter type are used in a tandem configuration. This setup, however, produces a Penning trap which could lead to increased background. We have performed test measurements showing that the filter energy of the pre-spectrometer can be reduced by several keV in order to diminish this trap. These measurements were analyzed with the help of a complex computer simulation, modeling multiple electron reflections both from the detector and the photoelectric electron source used in our test setup.Comment: 22 pages, 12 figure

Gastrointestinal lesions in patients with acquired immunodeficiency syndrome

"Introduction : Le syndrome de l'immunodéficience acquise (SIDA) s'accompagne souvent d'atteintes du tube digestif, tumorales ou secondaires à des infections opportunistes. Le but du travail est de déterminer les aspects endoscopiques et anatomo-pathologiques des atteintes digestives secondaires au SIDA et d'étudier leur corrélation. Patients et méthodes : 68 patients atteints du SIDA ont été explorés au service EFD-HGE sur une période de 5 ans. Tous les patients ont bénéficié d'une endoscopie œso-gastro-duodénale (EOGD) et/ou d'une iléo-coloscopie avec une étude anatomo-pathologique des biopsies. Résultats : Les lésions digestives hautes étaient: une œsophagite mycosique dans 19 cas, une gastrite congestive dans 14 cas, une gastrite ulcérative chez un patient, une gastrite érosive chez un patient, une duodénite congestive dans 9 cas et des lésions angiomateuses très évocatrices de la maladie de Kaposi dans 6 cas. L'étude anatomo-pathologique des biopsies a conclu à des lésions digestives hautes liées au SIDA dans 27 cas (53 %). Les lésions digestives basses étaient : une colite ulcérative dans 22 cas, des angiodysplasies dans 4 cas, une colite érosive dans 16 cas. La coloscopie totale était normale chez 2 patients. L'étude anatomo-pathologique des biopsies iléales et coliques a conclu à des lésions secondaires au SIDA dans 8 cas (18,1 %). Il existait une corrélation statiquement significative entre les aspects endoscopiques et anatomopathologiques spécifiques au SIDA (coefficient kappa = 0,730). Conclusion : Les atteintes digestives liées au SIDA sont assez fréquentes, elles étaient de 51,4 % dans cette étude dominées par les infections opportunistes. Une corrélation était retrouvée entre les lésions endoscopiques et spécifiques au SIDA.Background: The acquired immunodeficiency syndrome (AIDS) is often associated of the gastrointestinal lesions, tumor or secondary to opportunistic infections. The aim of this study is to determine the endoscopic and histopathological gastrointestinal lesions of AIDS and study their correlation. Patients and Method: 68 patients with AIDS were explored in our unit over a five-year period. All patients underwent an upper gastrointestinal endoscopy and/or a total colonoscopy with histopathological study of biopsies. The kappa coefficient was used to calculate the correlation between endoscopic and histopathological lesions specific to AIDS. Results: Upper gastrointestinal endoscopy revealed: fungal esophagitis in 19 cases, congestive gastritis in 14 cases, ulcerative gastritis in a patient, erosive gastritis in a patient, congestive duodenitis in 9 cases, and angiomatous lesions of Kaposi's sarcoma in 6 cases. Histopathological study of biopsies concluded to specific upper gastrointestinal lesions of AIDS in 27 cases (54%): Candida albicans in 19 patients, Kaposi's sarcoma in 6 cases, Cytomegalovirus (CMV) gastritis in 1 case, gastric cryptosporidiosis associated with Cytomegalovirus gastritis in 1 case. Colonoscopy objectified: ulcerative colitis in 22 cases, 4 cases of angiodysplasia, erosive colitis in 16 cases. Histopathological study of ileal and colonic biopsies concluded to specific lesions of AIDS in 8 cases (18.1%). Significant correlation was found between endoscopic and histopathological lesions specific of AIDS (kappa = 0.730). Conclusion: Gastrointestinal lesions specific of AIDS are fairly common, they were 52.2% in this study dominated by opportunistic infections. A correlation was found between endoscopic and histopathological lesions specific of AIDS in this study

Prenatal hypoxia induces increased cardiac contractility on a background of decreased capillary density.

Background: Chronic hypoxia in utero (CHU) is one of the most common insults to fetal development and may be associated with poor cardiac recovery from ischaemia-reperfusion injury,yet the effects on normal cardiac mechanical performance are poorly understood. Methods: Pregnant female wistar rats were exposed to hypoxia (12% oxygen, balance nitrogen)for days 10–20 of pregnancy. Pups were born into normal room air and weaned normally. At 10 weeks of age, hearts were excised under anaesthesia and underwent retrograde 'Langendorff' perfusion. Mechanical performance was measured at constant filling pressure (100 cm H2O) with intraventricular balloon. Left ventricular free wall was dissected away and capillary density estimated following alkaline phosphatase staining. Expression of SERCA2a and Nitric Oxide Synthases (NOS) proteins were estimated by immunoblotting. Results: CHU significantly increased body mass (P < 0.001) compared with age-matched control rats but was without effect on relative cardiac mass. For incremental increases in left ventricular balloon volume, diastolic pressure was preserved. However, systolic pressure was significantly greater following CHU for balloon volume = 50 μl (P < 0.01) and up to 200 μl (P < 0.05). For higher balloon volumes systolic pressure was not significantly different from control. Developed pressures were correspondingly increased relative to controls for balloon volumes up to 250 μl (P < 0.05).Left ventricular free wall capillary density was significantly decreased in both epicardium (18%; P <0.05) and endocardium (11%; P < 0.05) despite preserved coronary flow. Western blot analysis revealed no change to the expression of SERCA2a or nNOS but immuno-detectable eNOS protein was significantly decreased (P < 0.001) in cardiac tissue following chronic hypoxia in utero. Conclusion: These data offer potential mechanisms for poor recovery following ischaemia, including decreased coronary flow reserve and impaired angiogenesis with subsequent detrimental effects of post-natal cardiac performance

Nature inspired meta-heuristic algorithms for deep learning: recent progress and novel perspective

Deep learning is presently attracting extra ordinary attention from both the industry and the academia. The application of deep learning in computer vision has recently gain popularity. The optimization of deep learning models through nature inspired algorithms is a subject of debate in computer science. The application areas of the hybrid of natured inspired algorithms and deep learning architecture includes: machine vision and learning, image processing, data science, autonomous vehicles, medical image analysis, biometrics, etc. In this paper, we present recent progress on the application of nature inspired algorithms in deep learning. The survey pointed out recent development issues, strengths, weaknesses and prospects for future research. A new taxonomy is created based on natured inspired algorithms for deep learning. The trend of the publications in this domain is depicted; it shows the research area is growing but slowly. The deep learning architectures not exploit by the nature inspired algorithms for optimization are unveiled. We believed that the survey can facilitate synergy between the nature inspired algorithms and deep learning research communities. As such, massive attention can be expected in a near future