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Identifying the validity domain of machine learning models in building energy systems

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Energy and AI 2024年第1期15卷 328-341页

作者： martin Rätz patrick Henkel Phillip Stoffel Rita Streblow Dirk Müller RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor ClimateMathieustraβe 10Aachen52074Germany

The building sector significantly contributes to climate *** improve its carbon footprint,applications like model predictive control and predictive maintenance rely on system ***,the high modeling effort hinders practical *** learning models can significantly reduce this modeling *** ensure a machine learning model’s reliability in all operating states,it is essential to know its validity *** states outside the validity domain might lead to extrapolation,resulting in unpredictable *** paper addresses the challenge of identifying extrapolation in data-driven building energy system models and aims to raise knowledge about *** that,a novel approach is proposed that calibrates novelty detection algorithms towards the machine learning *** novelty detection algorithms are identified through a literature review and a benchmark test with 15 candidates.A subset of five algorithms is then evaluated on building energy ***,on two-dimensional data,displaying the results with a novel visualization *** on more complex multi-dimensional use *** methodology performs well,and the validity domain could be *** visualization allows for a profound analysis and an improved understanding of the fundamental effects behind a machine learning model’s validity domain and the extrapolation regimes.

关键词： Extrapolation detection Validity domain Novelty detection Machine learning Artificial neural network Data-driven model predictive control Building energy systems

Fatty acids derived from oviposition systems guide female black soldier flies(Hermetia illucens)toward egg deposition sites

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Insect Science 2024年第4期31卷 1231-1248页

作者： patrick Klüber Emna Arous Jeanny Jerschow Marco Fraatz Daniel Bakonyi martin Rühl Holger Zorn Department Bioresources Fraunhofer Institute for Molecular Biology and Applied EcologyGiessenGermany Institute of Food Chemistry and Food Biotechnology Justus Liebig University GiessenGiessenGermany

The black soldier fly,Hermetia illucens,comes with big promises for industrial purposes since its larvae feed polyphagously on a broad spectrum of organic ***,research focusing on adult flies is scarce,which is inconsistent with their reproductive relevance within the rearing *** particular,directed oviposition is a challenge in artificial ***,decomposing organic matter is commonly used as oviposition substrate,which has extensive potential for improvement in view of the lack of standardization and the risk of microbial ***,we identified three fatty acids and one fatty acid methyl ester derived from the surface of old oviposition sites and targeted to elucidate their effect on preference behavior and oviposition site selection using Y-olfactometry and prepared oviposition sites,*** to tetradecanoic acid attracted gravid females and stimulated oviposition most strongly,while decanoic acid demonstrated a repulsive *** kept in mixed-sex populations were attracted by tetradecanoic acid,resulting in a higher egg mass found in the compound box(3.0–11.4 fold),a≥2.3 fold reduction of nonspecifically deposited eggs,and the highest total egg ***,decanoic and dodecanoic acid caused females to lay a greater proportion of eggs nonspecifically outside both *** data suggest that fatty acids,especially tetradecanoic acid,are important cues for oviposition site selection in black soldier *** order to achieve a directed oviposition behavior,the role of further short-and long-chain fatty acids as attractants should be examined.

关键词： black soldier fly Hermetia illucens fatty acids insects as food and feed oviposition oviposition site selection tetradecanoic acid

The Influence of Biomass Cokes on the Microstructure and Thermal Shock Resistance of MgO-C Refractories

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China's Refractories 2024年第3期33卷 9-14页

作者： patrick GEHRE Magzhan KAPESSOV Stefan GUHL martin GRÄBNER Christos G.ANEZIRIS Institute of Ceramics Refractories and Composite MaterialsTU Bergakademie FreibergFreiberg 09599Germany Institute of Energy Process Engineering and Chemical Engineering TU Bergakademie FreibergFreiberg 09599Germany

In this study,biomass cokes from sunflower seed hull(SFSH)and wood pellets(WP)were added to a MgO-C batch(3 mass%C)to replace 1.1 mass%of *** hardening and carbonizing the samples,the influence of the biomass cokes on the microstructure and thermal shock resistance was *** replacement of flaky graphite by carbonized WP and SFSH reduced the bulk density and increased the apparent porosity after pressing and carbonization,but the degree was only *** was confirmed by SEM investigations,where the biomass-coke containing samples exhibited a microstructure with a higher amount of pores between the fine MgO *** thermal shock resistance of the porous wood pellet coke containing MgO-C is at the same level as the reference sample but not superior to it.

关键词： MgO-C carbon biomass microstructure thermal shock

Preparation and Characterisation of Corncob-Based Biosorbents in Côte d’Ivoire

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Advances in Materials Physics and Chemistry 2024年第8期14卷 178-195页

作者： Miezan Gnoan Ghislaine De Bouanzi patrick Grah Atheba Serge Kouassi Gbamélé martin Alla Aka Albert Trokourey Laboratory of Constitution and Reaction of Matter (LCRM) Flix Houphout-Boigny University Abidjan Cte dIvoire Laboratory of Environmental Sciences (LSE) Nangui Abrogoua University Abidjan Cte dIvoire

This study focuses on the preparation of corncob-based biosorbents. The chemical impregnation method was used to vary the chemical agent namely phosphoric acid H3PO4 (BA) and sodium hydroxide NaOH (BB). The physicochemical analysis of the two biosorbents indicated that under the same preparation conditions, the bio-sorbents have after activation yields lower than 50% (24.37% for BB and 49.09% for BA). In addition, the biosorbents have iodine index values between 444.17 mg/g and 418.79 mg/g and specific surfaces related to the adsorption of methylene blue ranging from 18.54 m2/g to 19.70 m2/g. The study of surface functional groups by using the Boehm test and pH zero point charge (pHPZC) confirmed the acidic nature of BA and BB biosorbents with respective values pHPZC = 4.01 and pHPZC = 4.90. The Langmuir method and BET analysis determined the specific surface areas by liquid phase adsorption of methylene blue as well as the porosity. The BET surface areas of BA and BB obtained are 72.01 m2/g and 63.10 m2/g respectively. The influence of the chemical activating agent on the formation of pores was confirmed by electron microscopy (SEM) analysis. From this study, it is found that the best activating agent for corn cobs was found to be phosphoric acid because the BA biosorbent was revealed to be the most favourable due to its surface area and good pore volume which are high compared to sodium hydroxide NaOH. Moreover, their application as adsorbent for effluent treatment could be explored.

关键词： Biosorbent Corncobs Chemical Activation Phosphoric Acid Sodium Hydroxide

Cosmetic or Dietary Vegetable Oils Sampled in the Cameroonian Market May Not Expose Consumers to Lipid Oxidation Products Generating Oxidative Stress and Inflammation

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American Journal of Plant Sciences 2024年第3期15卷 193-202页

作者： Ferdinand Kouoh Elombo Erika Van Damme Clara Delepine David Depraetere Ludovic Chaveriat Paul Lunga Keilah Nico Fréderic Njayou patrick martin Laboratory of Toxicology and Pharmacology Department of Biochemistry Faculty of Sciences University of Yaound&#233 I Yaound&#233 Cameroon Dé partement de Chimie IUT B&#233thune Universit&#233 d&#8217Artois B&#233thune France Unité Transformations & Agroressources (ULR7519) Universit&#232 d&#8217Artois-UniLaSalle Bethune France

Vegetable oils are a source of energy, essential fatty acids, antioxidants and fat-soluble vitamins useful for human health care and development. These oils also contribute to organoleptic quality of their products’ derivatives. However, their chemical and physical properties can be modified by the mode of their extraction, storage and distribution. These modifications might negatively affect the nutritional quality of the oils. The goals of this study were to: sample different vegetable oils for cosmetic or dietary use marketed in Cameroon, and verify purity and oxidation states of each kind of oil through determination of its acidity, iodine, peroxide, saponification, refractive indexes and the conformity of the labeling. The carotene content, the level of polar components and specific absorbance were also determined. As the result, six oils namely palm, palm kernel, coconut, black cumin, peanut and shea butter were collected. Apart from labeling, chemicals and physicals parameters analyzed were generally in accordance with the Cameroonian and Codex Alimentarius standard. This study suggests that vegetable oils sampled in the Cameroonian market may not expose consumers to lipid oxidation products generating pathological oxidative stress and inflammation. However, efforts in application of existing standard need to be done as far as labeling are concerned.

关键词： Vegetable Oils Quality Control Labeling Compliance Lipid Oxidation Oxidative Pathology

Management and Outcome of Urethral Strictures at Two Tertiary Health Facilities in Cameroon

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Open Journal of Urology 2024年第8期14卷 435-446页

作者： martin Divine Mokake Divine Enoru Eyongeta Ekani Mahamat Ekani Diana Nunga Theophile Chunteng Nana Ntungwetape Ngwane Mwambo Nalova Elroy patrick Weledji Chichom Alain Mefire Marcellin Ngowe Ngowe Department of Surgery and Specialties Faculty of Health Sciences University of Buea Buea Cameroon Department of Surgery Regional Hospital Buea Buea Cameroon Department of Surgery Regional Hospital Limbe Limbe Cameroon Department of Surgery Douala General Hospital Douala Cameroon

Introduction and Objectives: Urethral stricture is a reduction in the caliber of the urethral lumen impeding the outflow of urine. It predominantly affects males. The disease burden is severe in our milieu where access to specialized care is limited. Our goal was therefore to assess the management and outcome of male urethral stricture at two tertiary hospitals in Douala, Cameroon. Materials and Methods: This was a hospital-based retrospective study of patients managed for urethral stricture over 5 years (January 1st, 2017 to December 31st, 2021) at the Douala General and Laquintinie Hospitals. Data on sociodemographic, clinical, paraclinical, and treatment options were extracted using pre-structured forms. Data was analyzed using Statistical Package for Social Sciences (SPSS) version 28. Statistical significance was set at p-value Results: We exploited 130 medical records. The mean age of patients was 46.5 years. Dysuria and weak urine stream were the major presenting complaints (63.8% and 23.8% respectively). The etiology of urethral stricture was iatrogenic in 42.3% of cases. The strictures were mostly single (89.8%), and the bulbar urethra was most affected (46.9%). 28 patients had urinary tract infections and the most frequently isolated germ was E. coli in 29.6%. Direct visual internal urethrotomy (DVIU) was performed in 42.3% of cases. Surgery, especially excision and primary anastomosis (EPA) was done in 28.5% of cases. Major complications were wound infection, acute kidney injury (AKI), and urethrocutaneous fistulae affecting 3.1, 2.3, and 1.5% of cases respectively. The recurrence rate was 17% with a mortality rate of 0.08%. Conclusion: Urethral stricture is common in our adult male population. The cause is mainly iatrogenic and the bulbar urethra is most affected. Minimally invasive and open reconstruction are frequently used treatment options with significant recurrence rates in the long term.

关键词： Urethral Stricture Management Outcomes

Safe operation of online learning data driven model predictive control of building energy systems

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Energy and AI 2023年第4期14卷 536-549页

作者： Phillip Stoffel patrick Henkel martin Ratz Alexander Kumpel Dirk Muller RWTH Aachen University E.ON Energy Research CenterInstitute for Energy Efficient Buildings and Indoor ClimateMathieustraße 10Aachen52074Germany

Model predictive control is a promising approach to reduce the CO 2 emissions in the building ***,the vast modeling effort hampers the widescale practical ***,data-driven process models,like artificial neural networks,are well-suited to automatize the ***,the underlying data set strongly determines the quality and reliability of artificial neural *** general,the validity domain of a machine learning model is limited to the data that was used to train *** based on system states outside that domain,so-called extrapolations,are unreliable and can negatively influence the control *** present a safe operation approach combined with online learning to deal with extrapolation in data-driven model predictive ***,the k-nearest neighbor algorithm is used to detect extrapolation to switch to a robust fallback *** continuously retraining the artificial neural networks during operation,we successively increase the validity domain of the artificial neural networks and the control *** apply the approach to control a building energy system provided by the BOPTEST *** compare controllers based on two data sets,one with extensive system excitation and one with baseline *** system is controlled to a fixed temperature set point in baseline ***,the artificial neural networks trained on this data set tend to extrapolate in other operating *** show that safe operation in combination with online learning significantly improves performance.

关键词： Data-driven model predictive control Online learning Novelty detection Artificial neural networks Building energy systems

All inkjet-printed perovskite-based bolometers

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npj Flexible Electronics 2020年第1期4卷 297-301页

作者： Charles Trudeau patrick Beaupré martin Bolduc Sylvain G.Cloutier Department of Electrical Engineering École de Technologie SupérieureMontréalCanada Institut National d’Optique Québec QuébecCanada Department of Mechanical Engineering Universitédu QuébecàTrois-RivièresTrois-RivièresCanada

We show flexible bolometer devices produced entirely using digital inkjet printing on polymer *** bolometers consist of a silver interdigital electrode thermistor covered with a methylammonium lead trihalide perovskite absorber layer which shows good absorber characteristics at visible *** the standalone thermistor and the complete bolometer devices show polymer PTC thermistor-like behavior over a temperature range of 17 to 36℃,with a change in resistance up-to six orders of magnitude over this temperature *** addition of the perovskite absorber to the thermistor structure provides the illumination-dependent behavior proper to bolometers.

关键词： absorber perovskite illumination

Development and Implementation of a Rotating Nanoimprint Lithography Tool for Orthogonal Imprinting on Edges of Curved Surfaces

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Nanomanufacturing and Metrology 2021年第3期4卷 175-180页

作者： Shraddha Supreeti Ralf Schienbein patrick FeBer Florian Fern martin Hoffmann Stefan Sinzinger Electronics Technology Group Technical University of IlmenauIlmenauGermany Institute for Design and Precision Engineering Technical University of IlmenauIlmenauGermany Technical Optics Group Technical University of IlmenauIlmenauGermany JUMO GmbH&Co.KG FuldaGermany Microsystems Technology Group Ruhr-University BochumBochum.Germany

Uniform molding and demolding of structures on highly curved surfaces through conformal contact is a crucial yet often-overlooked aspect of nanoimprint lithography(NIL).This study describes the development of a NIL tool and its integration into a nanopositioning and nanomeasuring machine to achieve high-precision orthogonal molding and demolding for soft ultraviolet-assisted NIL(soft UV-NIL).The process was implemented primarily on the edges of highly curved plano-convex substrates to demonstrate structure uniformity on the ***-resolution nanostructures of sub-200-nm lateral dimension and microstructures in the range of tens of microns were ***,the nanostructures on the edges of the large,curved substrates were difficult to characterize ***,microstructures were used to measure the structure fidelity and were characterized using profilometry,white light interferometry,and confocal laser scanning *** of the restricted imaging capabilities at high inclinations for high-resolution nanostructures,the scanning electron microscope(SEM)imaging of the structures on top of the lens substrate and at an inclination of 45°was *** micro and nanostructures were successfully imprinted on the edges of the plano-convex lens at angles of 45°,60°,and 90°from the center of rotation of the rotating NIL *** method enables precise imprinting at high inclinations,thereby presenting a different approach to soft UV-NIL on curved surfaces.

关键词： Nanoimprint lithography Rotating NIL tool Curved surface Imprinting Nanopositioning