bluuebunny/crossref_metadata_2025 huggingface dataset:
CuO-Ga2O3 Thin Films as a Gas-Sensitive Material for Acetone Detection
Authors: Dyndal Katarzyna , Zarzycki Arkadiusz , Andrysiewicz Wojciech , Grochala Dominik , Marszalek Konstanty , Rydosz Artur
Published: June 2020

The p-n heterostructures of CuO-Ga2O3 obtained by magnetron sputtering technology in a fully reactive mode (deposition in pure oxygen) were tested under exposure to low acetone concentrations. After deposition, the films were annealed at previously confirmed conditions (400 °C/4 h/synthetic air) and further investigated by utilization of X-ray diffraction (XRD), X-ray reflectivity (XRR), energy-dispersive X-ray spectroscopy (EDS). The gas-sensing behavior was tested in the air/acetone atmosphere in the range of 0.1–1.25 ppm, as well as at various relative humidity (RH) levels (10–85%). The highest responses were obtained for samples based on the CuO-Ga2O3 (4% at. Ga).
Improved LiDAR Probabilistic Localization for Autonomous Vehicles Using GNSS
Authors: de Miguel Miguel Ángel , García Fernando , Armingol José María
Published: June 2020

This paper proposes a method that improves autonomous vehicles localization using a modification of probabilistic laser localization like Monte Carlo Localization (MCL) algorithm, enhancing the weights of the particles by adding Kalman filtered Global Navigation Satellite System (GNSS) information. GNSS data are used to improve localization accuracy in places with fewer map features and to prevent the kidnapped robot problems. Besides, laser information improves accuracy in places where the map has more features and GNSS higher covariance, allowing the approach to be used in specifically difficult scenarios for GNSS such as urban canyons. The algorithm is tested using KITTI odometry dataset proving that it improves localization compared with classic GNSS + Inertial Navigation System (INS) fusion and Adaptive Monte Carlo Localization (AMCL), it is also tested in the autonomous vehicle platform of the Intelligent Systems Lab (LSI), of the University Carlos III de of Madrid, providing qualitative results.
Benchmarking of Water, Energy, and Carbon Flows in Academic Buildings: A Fuzzy Clustering Approach
Authors: Alghamdi Abdulaziz , Hu Guangji , Haider Husnain , Hewage Kasun , Sadiq Rehan
Published: June 2020

In Canada, higher educational institutions (HEIs) are responsible for a significant portion of energy consumption and anthropogenic greenhouse gas (GHG) emissions. Improving the environmental performance of HEIs is an important step to achieve nationwide impact reduction. Academic buildings are among the largest infrastructure units in HEIs. Therefore, it is crucial to improve the environmental performance of academic buildings during their operations. Identifying critical academic buildings posing high impacts calls for methodologies that can holistically assess the environmental performance of buildings with respect to water and energy consumption, and GHG emission. This study proposes a fuzzy clustering approach to classify academic buildings in an HEI and benchmark their environmental performance in terms of water, energy, and carbon flows. To account for the fuzzy uncertainties in partitioning, the fuzzy c-means algorithm is employed to classify the buildings based on water, energy, and carbon flow indicators. The application of the developed methodology is demonstrated by a case study of 71 academic buildings in the University of British Columbia, Canada. The assessed buildings are grouped into three clusters representing different levels of performances with different degrees of membership. The environmental performance of each cluster is then benchmarked. Based on the results, the environmental performances of academic buildings are holistically determined, and the building clusters associated with low environmental performances are identified for potential improvements. The subsequent benchmark will allow HEIs to compare the impacts of academic building operations and set realistic targets for impact reduction.
Environmental Management in German Hospitals—A Classification of Approaches
Authors: Seifert Christin , Damert Matthias , Guenther Edeltraud
Published: June 2020

This paper analyzes organizational environmental performance and environmental management approaches in German hospitals. Based on data from an online survey and a subsequent cluster analysis, three groups of hospitals are identified: traditionalists, pragmatists, and environmentalists. The clusters differ regarding their organizational environmental performance, i.e., the environmental management elements adopted (policy, goals, structures, processes, and monitoring) and the environmental issues addressed (energy, water, material consumption, waste, emissions into water and air). The environmental management approaches hospitals adopt range from least to most active. Despite perceived stakeholder pressure being generally low, differences between the clusters can be observed. The most relevant stakeholders are internal ones, i.e., management and owners, rather than external ones. Furthermore, some organizational characteristics distinguish the clusters. This paper adds knowledge in the under-researched setting of hospitals and discusses managerial possibilities for the types of hospitals to increase their organizational environmental performance and to pursue a more holistic environmental approach.
Software Application for Organizational Sustainability Performance Assessment
Authors: Grecu Valentin , Ciobotea Radu-Ilie-Gabriel , Florea Adrian
Published: June 2020

Sustainability performance assessment is a challenge for many companies due to the heterogeneity of indicators and the lack of a standardized reporting framework. This paper describes a software solution that simplifies the sustainability reporting process and is useful for decisions concerning sustainable management. We analyzed various indicators from public sustainability reports of five companies and obtained some relevant results using the tool that we developed based on mathematic algorithms and an aggregation model of different indicators. The software application calculates a Global Sustainability Index based on the proposed model of the sustainable organization described in this paper. An optimal solution is very rare in the transition towards the sustainable organization and compromises are required most frequently between environmental, economic and social aspects on the one hand and the expectations of the stakeholders on the other hand. The proposed tool helps users to cope with these challenges and takes into consideration that information is not always available and precise. Another feature offered by the tool is that besides simplifying sustainability performance assessment, it highlights low performance indicators and offers suggestions for improvement based on a genetic algorithm.
Mainstreaming Energetic Resilience by Morphological Assessment in Ordinary Land Use Planning. The Case Study of Moncalieri, Turin (Italy)
Authors: Mohabat Doost Danial , Buffa Alessandra , Brunetta Grazia , Salata Stefano , Mutani Guglielmina
Published: June 2020

Energetic resilience is seen as one of the most prominent fields of investigation in the upcoming years. The increasing efficiency of urban systems depends on the conversion of energetic production of buildings, and therefore, from the capacity of urban systems to be more rational in the use of renewable resources. Nevertheless, the integration of the energetic regulation into the ordinary urban planning documents is far from being reached in most of planning processes. In Italy, mainstreaming energetic resilience in ordinary land use planning appears particularly challenging, even in those Local Administrations that tried to implement the national legislation into Local Building Regulation. In this work, an empirical methodology to provide an overall assessment of the solar production capacity has been applied to selected indicators of urban morphology among the different land use parcel-zones, while implementing a geographic information system-based approach to the city of Moncalieri, Turin (Italy). Results demonstrate that, without exception, the current minimum energy levels required by law are generally much lower than the effective potential solar energy production that each land use parcel-zone could effectively produce. We concluded that local planning processes should update their land use plans to reach environmental sustainability targets, while at the same time the energetic resilience should be mainstreamed in urban planning by an in-depth analysis of the effective morphological constraints. These aspects may also represent a contribution to the international debates on energetic resilience and on the progressive inclusion of energy subjects in the land use planning process.
Frames in Outdoor Environmental Education Programs: What We Communicate and Why We Think It Matters
Authors: Činčera Jan , Johnson Bruce , Kroufek Roman , Kolenatý Miloslav , Šimonová Petra
Published: June 2020

This paper discusses the application of frame analysis as a method of designing and evaluating outdoor environmental education programs. In particular, it investigates what frames are communicated in these programs, why and how program leaders focus on communicating particular frames, and how students interact with these frames. Five outdoor environmental education programs for elementary school students were analyzed. We used a qualitative approach that combined field observation, interviews with program leaders (N = 15), qualitative findings based on questionnaires collected from the participants after completing the programs (N = 365), and interviews with some of the students (N = 10). According to the results, while the leaders intensively applied various surface frames to attract student interest and organize the program activities, the deep frames aimed for in the main program messages connected with the program goals often remained implicit and were not recognized by the students.
Corporate Social Responsibility towards the Environment in Lublin Region, Poland: A Comparative Study of 2009 and 2019
Authors: Żelazna Anna , Bojar Matylda , Bojar Ewa
Published: June 2020

Today’s businesses have a huge impact on the environment. Enterprises overuse available natural resources, and emit hazardous pollutants; thus, they contribute to the advancing degradation of existing ecosystems, causing serious threats to the biological diversity of our planet. Hence, there is an urgent need to undertake diverse actions to reduce the adverse impact of businesses, households, and whole societies on the environment, and stop its degradation. The goal of this paper is to present research findings from the study carried out in 2019 and compare these findings with the study carried out in 2009, in order to identify and analyze the most frequent environmental activities undertaken by enterprises operating in the Lublin region. The ranking method was used in the study. The research findings show that over the last 10 years respondents’ opinions on the most effective economic instruments used in pursuing ecological policies remained unchanged. Moreover, respondents point to numerous tangible benefits resulting from ecological activity. In 2019, like in 2009, most pro-ecological investments were financed with enterprises’ own funds. Over the 10-year period between 2009 and 2019, the most frequent pro-environmental activities, as well as the returns on ecological investment periods, have changed. The study showed that enterprises responsibly consider environmental impacts of their activities and undertake actions aimed at preserving the environment and its resources.
Intense Cyclones in the Black Sea Region: Change, Variability, Predictability and Manifestations in the Storm Activity
Authors: Maslova Veronika N. , Voskresenskaya Elena N. , Lubkov Andrey S. , Yurovsky Aleksandr V. , Zhuravskiy Viktor Y. , Evstigneev Vladislav P.
Published: June 2020

Cyclonic activity in the midlatitudes is a form of general atmospheric circulation, and the most intense cyclones are the cause of hydrometeorological anomalies that lead to economic damage, casualties and human losses. This paper examines the features of variability of intense cyclonic activity in the Black Sea region and the examples of their regional manifestations in the storm types. Based on 6-hourly NCEP/NCAR reanalysis data on 1000 hPa geopotential height fields with 2° × 2° spatial resolution and using the methodology by M.Yu. Bardin, objective data were obtained for the identification and estimation of the frequency of deep cyclones (reaching 0.75 and 0.95 quantiles by intensity and depth—intense and extreme cyclones, respectively) for the Black Sea region during the period 1951–2017. Additionally, a specific methodology of more precise cyclone identification based on spherical spline interpolation was successfully applied, and then the two methodologies were compared. The key point of the study is the following: In the background of negative significant linear trends and interdecadal variability (period of about 35 years), typical scales of their interannual variability on the periods of about 2.5–3.5 and 6–8 years were identified. These periods coincide with the time scales of the North Atlantic Oscillation and El Nino–Southern Oscillation, providing an outlook for further study of the patterns of their connection. Besides, seasonal forecasts of frequency of intense cyclones in the Black Sea region were successfully modeled using an artificial neural network technique. Finally, the case studies of regional manifestations of deep cyclones in the types of storms in the northern Black Sea coast revealed substantial differences in the location of deep centers of cyclones and storm tracks associated with the large-scale pressure fields.
Risk Allocation in Unsolicited and Solicited Road Public-Private Partnerships: Sustainability and Management Implications
Authors: Castelblanco Gabriel , Guevara Jose , Mesa Harrison , Flores Diego
Published: June 2020

Risk allocation plays a crucial role in the successful development of public-private partnership (PPP) projects. However, despite being an important topic for scholars and practitioners, the existing literature does not provide sufficient evidence on how managing risks in solicited (SP) and unsolicited (USP) road PPP projects, and subsequently, on what the sustainability implications are for such managerial processes. This study aims to extend risk allocation studies by analyzing contracts in Chilean highway PPPs over the last decade based on a systematic content analysis framework and case study data. The framework was developed through line-by-line coding of contract provisions associated with risk-related issues, and data were collected from semi-structured interviews with Chilean PPP practitioners. Results show that, although the majority of risks are either shared or transferred to the private party in most contracts, there are important variations in the way allocation procedures are implemented for SPs and USPs. Contracts analyzed revealed that risk arrangement mechanisms have usually focused on the economic dimension of sustainability without fully incorporating social and environmental considerations, increasing protests in the long-term. Conclusions indicate that risk allocation procedures and sustainability considerations are highly dependent on project-specific features and contextual factors. Overall, the analysis uncovers that the level of autonomy given to the private sector in both SPs and USPs has contributed to properly manage technical and economic risks, but has failed to successfully allocate social and environmental concerns.
Relationships between Players’ Physical Performance and Small-Sided Game External Responses in a Youth Soccer Training Context
Authors: Castillo Daniel , Lago-Rodríguez Angel , Domínguez-Díez Marta , Sánchez-Díaz Silvia , Rendo-Urteaga Tara , Soto-Célix María , Raya-González Javier
Published: June 2020

The aim of this study was twofold: 1) To compare players’ physical performance and small-sided game (SSG) external responses among three young soccer age categories (i.e., under 14 (U14), under 16 (U16), and under 18 (U18)); and 2) to examine their relationships among physical performance and SSG external responses in each age category. Players’ physical performance was evaluated via several tests and external responses were collected during a four vs. four plus goalkeepers SSG. Main results showed that while older players presented better linear straight sprinting tests (LSSTs) (U18 and U16 vs. U14, p < 0.01), repeated sprint ability (RSA) (U18 vs. U16 and U14 p < 0.01), and change of direction ability (CODA) (U18 and U16 vs. U14, p < 0.01, ES = 2.34−2.72) performances, these differences were not consistent with their SSG external responses (U16 vs. U14, p < 0.01; U18 vs. U16, p < 0.01). Conversely, higher number of associations between players’ physical performance and SSG external responses were found in younger players in comparison to the older ones. These results suggest that while greater physical performance in younger players (i.e., U14) could allow them to exhibit higher external responses, greater physical performance did not influence older players’ (i.e., U18) SSG external responses.
Effect of U-Turns and Heavy Vehicles on the Saturation Flow Rates of Left-Turn Lanes at Signalized Intersections
Authors: Abuhijleh Abdelrahman , Dias Charitha , Alhajyaseen Wael , Muley Deepti
Published: June 2020

The Saturation Flow Rate (SFR) is a primary measure that can be used when estimating intersection capacity. Further, the efficiency of signal control parameters also depends on the accuracy of assumed SFR values. Driver behavior, type of movement, vehicle type, intersection layout, and other factors may have a significant impact on the saturation flow rate. Thus, it is expected that driving environments that have heterogeneous driver populations with different driving habits and cultures may have different SFRs. In practice, the proposed SFRs based on US standards (Highway Capacity Manual, 2016) have been adopted in the State of Qatar without validation or calibration to consider the local road environment and the characteristics of the driving population. This study aims to empirically analyze the saturation flow rates for exclusive left-turn lanes and shared left- and U-turn lanes at two signalized intersections in Doha city, while considering the effects of heavy vehicles and U-turn maneuvers. Empirical observations revealed that the average base SFR, i.e., when the influences from heavy vehicles and U-turns were excluded, could vary approximately from 1800 vehicles per hour per lane (vphpl) to 2100 vphpl for exclusive left-turning lanes and approximately from 1800 vphpl to 1900 vphpl for shared left- and U-turning lanes. Furthermore, this study proposed different adjustment factors for heavy vehicle and U-turn percentages which can be applied in practice in designing signalized intersections, particularly in the State of Qatar.
Design of Experiment (DOE) Analysis of 5-Cell Stack Fuel Cell Using Three Bipolar Plate Geometry Designs
Authors: Wilberforce Tabbi , Olabi Abdul Ghani
Published: June 2020

The investigation conducted is aimed at establishing the best operational conditions to obtain the best output of a 5-cell stack Proton Exchange Membrane fuel cell (PEMFC) with three different bipolar plate geometries. The work further explores the best input parameters that will yield the maximum voltage, current power as well as fuel efficiency from each of the three designs under investigation. A polarization curve was generated for each of the three designs and a surface response plot developed for each experiment. The work concluded that the spiral design performed very well compared to the other designs under investigation and even existing on the fuel cell market.
Learning Programming Language in Higher Education for Sustainable Development: Point-Earning Bidding Method
Authors: Chen Tzer-Long , Hsiao Tsung-Chih , Kang Tsan-Ching , Wu Ting-Yuan , Chen Chih-Cheng
Published: June 2020

Promoting learning passion for students in higher education is a vital and challenging issue. Due to the swift changes in society and technology development, many convenient and interesting technologies increasingly interfere with students’ learning performances and reduce students’ motivation for attending classes. For example, mobile games and social networking have led students to lose their passion for learning. MAPS (Mind Mapping, Asking Questions, Presentation, Scaffolding Instruction) is a flipped teaching model which has been proved as an effective approach to increasing students’ reflective learning, allowing students to devote to self-learning and recovering their passion for learning. Thus, this study employed a MAPS teaching strategy that adopts a point-earning approach to encourage students to learn from peer feedback while the teacher can understand students’ learning from the process. When the class is over, students can exchange the points for other rewards through a bidding mechanism which encourages students to regain passion for learning. The concept of Scaffolding Instruction points out that allowing students to sense positive peer pressure, which is caused by their peers’ improvements, and the atmosphere where their peers are studying hard can enhance their learning motivation and reflection. The empirical results of this study found that peer assessment and feedback can improve the learning effectiveness of students with poor performance.
Copyright Management by Contemporary Art Exhibition Institutions in Poland: Case Study of the Zachęta National Gallery of Art
Authors: Pluszyńska Anna
Published: June 2020

The mission of cultural institutions is the expression of sustainable development, which assumes a specific social order based on respect for the right of access to culture and care for the common good which is cultural heritage, in order to preserve it for future generations. To best implement its social mission, the essence of museum activities is not only collecting resources but also promoting the collection. In addition, promotion in accordance with the principle of openness and the conviction that cultural heritage is a common good, which is why it should be available to the widest possible public. Copyright in artworks often stands in the way of implementing an open approach to the dissemination of collections. Contemporary museums and galleries of art are in a special situation; their collections are not yet in the public domain, and so they cannot be freely distributed. The undertaken research problem explores how cultural institutions in Poland manage the copyright of collections in order to carry out their mission in a sustainable way. In this context, copyright is treated as an important intangible resource of a cultural institution. The case study was used as the research strategy in order to understand the subject. Activities implemented at the Zachęta National Gallery of Art in Warsaw were described.
Strategies to Combat Heat Stress in Broiler Chickens: Unveiling the Roles of Selenium, Vitamin E and Vitamin C
Authors: Shakeri Majid , Oskoueian Ehsan , Le Hieu , Shakeri Mehdi
Published: June 2020

Heat stress compromises efficient poultry production by impairing growth performance and increasing mortality. Mechanisms to dissipate excess heat divert energy from efficient production. This includes increased energy expenditure for respiration, oxidative stress and micronutrient absorption. The fortification of diets with particular feed additives has been known as one of the most important approaches to minimize the negative impacts of heat stress on broiler production. In this context, the promising functional feed additives appeared to be selenium and vitamins E and C. The fortification of broiler diets with these feed additives has been proven to enhance the function of vital organs, immune system response and growth performance of broilers under heat stress. The current review highlights recent successful experiences in the alleviation of heat stress symptoms in broilers using the above-mentioned additives. Selenium and vitamins E and C enhanced production performance in broiler chickens challenged with acute heat stress. The combination of these additives, by employing multiple mechanisms and through synergistic effects, improves heat stress symptoms more efficiently than their individual forms. Emerging literature reveals that selenium and vitamins E and C are involved in close interactions to protect proteins and lipids from oxidative damage and boost immune system function.
EFFECT OF MICROFILLERS BASED ON NATURAL WOLLASTONITE ON PROPERTIES OF FINE-GRAINED CONCRETE
Authors: Karpikov E. , Lukutcova N. , Soboleva G. , Golovin S. , Cherenkova Yu.
Published: June 2020

The possibility of obtaining effective highly dispersed additives from natural wollastonite is substantiated and their influence on the properties of fine-grained concrete is investigated. On the basis of wollastonite, a complex micro-filler with particle sizes up to 100 microns was developed, obtained by joint grinding with quartz sand in a 3:1 ratio in a ball mill in the presence of an anionic surfactant naphthalene-formaldehyde type C-3 and a calcium stearate hydrophobizer technical C-17. A suspension of wollastonite with a modal particle diameter of 405 nm was obtained by pre-grinding wollastonite and anionic surfactant in a ball mill, with their further ultrasonic treatment in a bath-type activator. Mathematical models of the dependence of compression and bending strength on the content of the initial components are developed. It is established that the complex microfill leads to an increase in the strength of fine-grained concrete in bending by 2 times, in compression by 1.7 times with its content in the composition of fine-grained concrete in the amount of 10% by weight of cement. Wollastonite suspension increases the bending strength of fine-grained concrete to 3.1 MPa, compression to 57.8 MPa. The results of qualitative x-ray phase analysis showed that the total intensity of diffraction maxima of not fully hydrated alite C3S, belite C2S grains and their aggregates in cement stone with wollastonite decreases by 1.5-2 times compared to the control composition. This is most likely due to the amorphous nature of the wollastonite surface after grinding in a ball mill and ultrasonic dispersion in a bath-type activator. In addition, such particles are the centers of crystallization. Their needle-like shape contributes to the reinforcement of the structure by crystallizing new formations of cement stone.
Surfaces et variétés algébriques de diviseur deux
Authors: Godeaux Lucien
Published: June 2020

Construction de surfaces et de variétés algébriques dont le diviseur de Severi est égal à deux.
Pentasphères attachés à une surface
Authors: Backès Fernand
Published: June 2020

Un premier pentasphère où interviennent la sphère harmonique et les sphères de courbure géodésique des lignes de courbure, conduit à une propriété anallagmatique caractéristique des surfaces isothermiques. Un second pentasphère, déduit d'ailleurs du premier, nous a permis de découvrir, en liaison avec les cercles une curieuse propriété des sphères de courbure principale.

Un appendice est consacré aux pseudogéodésiques anallagmatiques.
Fonctions spéciales. Fonctions hypergéométriques et polynômes de Jacobi et de Tchebycheff relatifs aux équations polyvibrantes généralisées
Authors: Mangeron Dumitru Ion , Oguztöreli Mehmet N. , Mangéron J.
Published: June 2020

On donne quelques théorèmes concernant les prototypes des équations polyvibrantes généralisées et on en déduit les fonctions hypergéométriques et les polynômes de Jacobi et de Tchebycheff relatifs à ces prototypes.
Fonctions de type S à valeurs dans un b-espace
Authors: Cnop-Grandsard Francine
Published: June 2020

Nous définissons deux espaces de fonctions différentiables à décroissance rapide, prenant leurs valeurs dans un 6-espace, montrons qu'ils coïncident si le 6-espace est topologique, mais qu'ils sont en général différents.
Sur une hypersurface cubique de l'espace à quatre dimensions
Authors: Godeaux Lucien
Published: June 2020

Construction de la variété image d'une involution cyclique du troisième ordre appartenant à une hypersurface cubique de l'espace à quatre dimensions. Applications.
Sur les normales anallagmatiques
Authors: Backès Fernand
Published: June 2020

Nous appelons ainsi des cercles normaux à une surface, toutefois plus généraux que les cercles cycliques, et jouissant, comme la droite normale à la surface, d'une propriété où interviennent des cercles ¨P, ce qui assure le caractère anallagmatique.
Lumière parasite dans les spectromètres Ebert-Fastie à simple passage
Authors: Marette G.
Published: June 2020

The wavelength distribution and relative intensity of stray radiation due to double dispersions have been calculated for single-pass in-plane Ebert-Fastie grating monochromators in order to correct previous spectroscopic results.
Le groupe des automorphismes des espaces affins à plus de deux dimensions sur un presque-corps proprement dit
Authors: Nizette Noël
Published: June 2020

On montre essentiellement que le groupe des automorphismes d'un espace affin à plus de deux dimensions sur un presque-corps proprement dit K est le groupe engendré par les automorphismes

1. [formula], où σ est un automorphisme quelconque de K, quels que soient les ai ≠ 0 et les bi dans K

2. {χ'i = χφ(i)(i = 1,...,n) quelle que soit la permutation φ des nombres 1,...,n.
A new approach to the equilibrium configuration of the stellar envelopes
Authors: Singh Bijai , Ram Rishi
Published: June 2020

Considering the physical structure of the stellar envelope a new solution of the equation of equilibrium is obtained, which is free of approximations. In determination of the mass in the stellar envelope Chandrasekhar's solution requires further approximation in the process of integration, whereas new solution obtained here requires no approximation. In the particular case of vanishing radiation pressure results are in full agreement with those of Chandrasekhar. The application of result in a stellar model is also discussed and neff is calculated. The expression for neff assumes a simple form and its typical values are the same as obtained by Chandrasekhar.
Factorization properties of perturbative contributions to the collision operator
Authors: Piasecki Jarosław
Published: June 2020

On démontre une propriété de factorisation de certaines classes de contributions perturbatives à l'opérateur de collision.
On an extended procedure of analytical continuation in Non-Equilibrium Statistical Mechanics
Authors: George Claude D.
Published: June 2020

A classification of correlations into categories of n-correlations is introduced and a i∈-rule which extends the procedure of analytical continuation is proposed in order to evaluate explicitly each term of the series, in the formal solution of the Liouville-von Neumann equation.
Étude d'un système de stabilisation en phase d'un klystron dans la bande de 27 à 37 Ghz (II)
Authors: Guisset J.-L.
Published: June 2020

Phase-locked klystrons in the 27 to 37 GHz range, constitute the electromagnetic field source of a molecular beam resonance apparatus. The klystrons are phase-locked in the whole of their working range by the use of fixed microwave reference frequencies and calibrated I. F. interpolating frequencies.

The servo-system was tested by a phase comparison at 22.8 GHz, between a phase-locked klystron and a N15H3-maser ; this set up enabled us to measure the frequency stability of the klystron. The value is : Δf/f = 8.10-11 for a 1 sec. measurement-time.
Sur les surfaces algébriques de genre zéro et de genre linéaire un (seconde note)
Authors: Godeaux Lucien
Published: June 2020

Détermination des surfaces non rationnelles de genres pa = pg = o, p(1) = 1, contenant un certain nombre de courbes elliptiques isolées dont certains multiples appartiennent à un faisceau linéaire de courbes elliptiques.
Sur les systèmes optimaux aux paramètres
Authors: Mangeron Démètre J. , Poterasu V. F. , Oguztöreli Mehmet N.
Published: June 2020

Les auteurs, tout en continuant leurs études concernant les systèmes optimaux aux paramètres, donnent dans cette Note une nouvelle démonstration de la condition de transversalité qui se réfère à de tels systèmes et exposent ensuite les résultats des calculs relatifs à un système autonome linéaire à deux paramètres.
Observations, par ballon stratosphérique, du spectre solaire à 1,85 microns avec un pouvoir de résolution de 135.000
Authors: Zander R.
Published: June 2020

Le 6 avril 1970, l'Institut d'Astrophysique de l'Université de Liège a lancé une nacelle stratosphérique transportant un télescope de 40 cm d'ouverture et un spectromètre à réseau du type Ebert-Fastie, de 2,50 m de focale. Les spectres solaires obtenus dans la bande de H2O, centrée à 1,87 microns, avec une résolution spectrale de .04 cm-1, ont permis de déterminer avec grande précision plus de 60 raies solaires pour la plupart non encore identifiées, entre 5480.0 et 5382 cm-1.

L'étude de raies d'absorption dues à la vapeur d'eau tellurique indique que la stratosphère est sèche, avec un taux de mélange moyen de l'ordre de 2 X 10-6gg-1 ; la possibilité d'une augmentation du taux de mélange au-dessus de 40 km d'altitude n'est pas à exclure au stade actuel de l'exploitation des données.
A study by electronic paramagnetic resonance and Mössbauer spectroscopy of some lunar samples collected by Apollo 12
Authors: Duchesne Jules , Read M. , Grandjean F. , Gérard A. , Depireux Joseph
Published: June 2020

Les auteurs ont soumis à l'étude, par résonance paramagnétique électronique et par effet Mössbauer, quelques échantillons lunaires, sous forme de roches compactes et de poussière, prélevés par Apollo 12 dans l'Océan des Tempêtes.

Ces recherches ont conduit à une importante discordance par rapport aux observations antérieures dues à Apollo 11, à savoir la très faible concentration des composés titanifères. Par contre, la contribution minime des ions ferriques et la présence probable de fer métallique, qui se déduisent de l'examen combiné par les deux méthodes en cause, sont en complet accord avec les analyses dues à la mission précédente.
Gradients spectrophotométriques d'un modèle de noyau de galaxie
Authors: Vandekerkhove Edgard
Published: June 2020

Le gradient spectrophotométrique est calculé, de l'ultraviolet à l'infra-rouge, pour un noyau de galaxie analogue à celui de M 31. Il est variable selon la longueur d'onde ; il est maximum 4,5 en λ = 0,4µ et il atteint 4,7 en λ = 2,5 µ ; il est minimum 3,1 en λ = 0,6µ et 0,1 en λ = 0,22µ.

Le déplacement dopplérien de tout le spectre vers les grandes longueurs d'onde produit ainsi des effets différents sur ce gradient selon la région spectrale où se font les mesures ; on observe un maximum pour z = 2-1,6-0,3 ou 0 selon que les mesures sont faites respectivement en λ = 2-1-0,5 ou 0,4µ.
Étude par spectroscopie d'absorption dans l'infrarouge des complexes par transfert de charge formés en solution par les halogènes avec différents donneurs d'électron
Authors: Cahay René
Published: June 2020

Infrared absorption spectrometry offers an excellent way for studying the donor-acceptor complexes with halogens as electron acceptors, as the stretching vibration of the halogen molecule becomes active in infrared in such kind of complexes.

We have studied the position in frequency and the intensity of the halogen stretching vibration band for the complexes of bromine and iodine with benzene and some of its halogenated and methylated derivatives and of iodine with different donors, especially amines and organic sulfur derivatives.

It is shown that the intensity of this band appears to be a characteristic of the donor-acceptor interaction much more sensitive than the frequency shift and can be correctly evaluated from the molecular properties of the partners on the basis of the theory proposed by Person and al.
Synthèses et propriétés de Schiff IV. Étude cinétique de la solvolyse d'une famille d'ɑ-phénylimino-benzoyl-acétanilides (PIBAZ)
Authors: Bruylants Albert , Fastrez Jacques
Published: June 2020

A series of azomethines derivated from the α-phenylimino-benzoyl-acetanilide (PIBA) of general formula, PIBAZ : [formula] with [formula], was submitted to acidic solvolysis.

Experimental results of a kinetic study, in an alcohol-water solvent, led to develop a reaction scheme of two nucleophilic additions simultaneously occuring at the protonated azomethinic bond : [formula]

the first one (I) giving an amino-ether (ki) which can only reverse to the original reactants (k-1) and the second one (II) generating an amino-alcohol(kII) which rapidly decomposes into the final products (P) : α, β-dioxo-dihydrocinnamanilide (C6H5— CO— CO— CO— NH— C6H5) and the corresponding aniline (Z— C6H4— HN2). This process undergoes general acid-base catalysis.
Kinetic Theory of Inhomogeneous Rotating Self-gravitating Systems : The Linearized Collisionless Boltzmann Equation
Authors: Haggerty M. J.
Published: June 2020

The problem of finding modes of small oscillations of a rotating self-gravitating system with strong inhomogeneities in directions perpendicular to the axis of rotation has been reduced to solving a two-dimensional linear integral equation. The kernel is complicated, but the nonresonant and resonant parts are self-adjoint for neutrally stable oscillations. Strong inhomogeneities along the axis of rotation, and effects of differential rotation, have not been included in this cylindrical model. The Coriolis force is retained, and no restrictions are imposed concerning the relative sizes of the epicycle radii and the scale of inhomogeneities of the unperturbed distribution.
Nouvelle méthode de mesure directe des déformations
Authors: Rezette Yves
Published: June 2020

Une extension de la méthode des moirés dans le cadre de l'optique physique nous permet de décrire une nouvelle méthode de mesure des déformations en lumière spatialement cohérente qui se rattache à la méthode spectroscopique mais est plus aisée à réaliser.
On linear relations between vorticity and current density generated by a pseudo-stationary shock in plane flows of conducting gases
Authors: Dwivedi R. P. , Mishra R. S.
Published: June 2020

Kanwal established two linear relations between vorticity and current density generated behind shock waves in two dimensional stationary flows of conducting gases. He also showed that vorticity generated by a shock in conducting gases is no longer derivable purely from dynamical relations as in non-conducting gases. The object of the present paper is to generalize Kanwal's result to pseudo-stationary case by employing an easier and shorter technique for investigating two linear relations between vorticity and current density generated behind a pseudo-stationary magneto-gas dynamic shock wave in plane flows.
Action of Electromagnetic Radiations on Proteins. I. Irradiation of Bovine Serum Albumin by Gamma Rays
Authors: Colson C. , Fredericq E.
Published: June 2020

Bovine serum albumin solutions (1 g/dl, pH 7) have been irradiated by moderate and high doses of gamma rays (1 to 50 Mrads) under air and in vacuo.

The ultraviolet spectrum is modified between 250 and 325 nm, the absorbance strongly increasing with dose, particularly at 250 nm and a little less in the 280 nm band. This is interpreted as arising from oxidation of the aromatic rings.

The variations of viscosity and sedimentation coefficients with dose indicate an unfolding of molecules followed by aggregation. The effects are stronger in air than in vacuo.

Chromatographic analysis indicates a progressive destruction of aminoacid residues, the most affected being the sulfur-containing ones and the cyclic ones (Phe, Tyr, and His). The effects are stronger in vacuo than in air.

An important decrease of levorotation at 589 nm is brought about by irradiation and attributed to destruction of asymmetry, either by direct action on the asymmetric carbons or by modifications of their environment.

Enzymic susceptibility to trypsin and chymotrypsin action increases at low doses and decreases at higher doses of irradiation, in reason of denaturing effects followed by aggregation and destruction of aminoacids. Irradiation in the dry state produces different modifications in the ultraviolet spectrum. Viscosity and sedimentation data indicate alterations only at very high doses. The extent of aminoacids destruction is similar to what happens in solution but results are more uniform. Enzymic susceptibility and optical rotation are slightly affected.

Chemically produced OH radicals (Fenton reagent) have very little action on similar properties of serum albumin solutions.

The effects of irradiation are grouped in two main classes. First spectral excitation, denaturation and aggregation mostly due to the action of oxidative radicals such as HO2* which are favoured by oxygen ; second the destruction of aminoacids and the decrease of optical rotation attributed to reducing species such as H* or H2O- which would be inhibited by oxygen.
Sur le système canonique des surfaces algébriques triples (seconde note)
Authors: Godeaux Lucien
Published: June 2020

Construction du système canonique de certaines surfaces algébriques images d'involutions cycliques du troisième ordre qui n'ont qu'un nombre fini de points unis appartenant à des surfaces algébriques.
Sur le système canonique des surfaces algébriques triples (troisième note)
Authors: Godeaux Lucien
Published: June 2020

Formation du système canonique d'une surface image d'une involution cubique cyclique n'ayant qu'un nombre fini de points unis de première espèce, appartenant à une surface algébrique.
Considérations diverses sur les enveloppes de sphères à deux paramètres
Authors: Backès Fernand
Published: June 2020

Nous mettons notamment en évidence certaines sphères qui, tout en n'étant pas des sphères de Ribaucour, ont néanmoins leurs points caractéristiques répartis sur le cercle générateur d'un système cyclique.
Rational approximations for exponential integrals En(x)
Authors: Verbeeck Paul
Published: June 2020

Methods are sought for obtaining approximations in the form of closed expressions for the exponential integrals in the range (0, ∞) using an adapted τ-method of Lanczos.
Effet d'une erreur affectant une étoile de référence intervenant dans la réduction des positions astrométriques au point d'application de cette erreur
Authors: Debehogne H.
Published: June 2020

Lorsque l'on applique un écart à la position d'une étoile de référence et que l'on effectue la réduction, l'écart ne se transporte pas intégralement sur la position recalculée de l'étoile. Ce phénomène dépend du nombre d'étoiles de référence, de la place qu'elles occupent sur le cliché et du nombre de constantes de plaque.

L'idée communément acceptée est que l'effet de l'erreur atteint son minimum au centre. Expérimentalement nous avons déterminé toute une série de cas où l'erreur n'est pas minimum au centre.
A theorem in dynamics of correlations - II
Authors: Hénin Françoise
Published: June 2020

It is shown, in the case of interacting phonons (classical or quantum) and of interaction between light and a bounded electron, that certain successions of monocorrelations are negligible in the thermodynamic limit. In general, monocorrelations are those correlations which can be reached in one step from the vacuum. However, in the light-atom interaction, this definition requires some modifications because of the discrete character of the atomic spectrum.
Perturbation series in operator and superoperator formalism. II
Authors: Turner John Wm.
Published: June 2020

The study of the transformation superoperator x-1 recently introduced by Prigogine et al., is pursued. The comparison in the non-dissipative case between the Wigner-Brillouin perturbation series and the series for x-1 already performed for a restricted class of terms, is now extended to all terms.
Nonlinear pulsations and stability of rapidly rotating columns
Authors: Tassoul Jean-Louis
Published: June 2020

In this note we discuss the influence of a large angular momentum on nonlinear axisymmetric motions of centrally condensed bodies. In order to illustrate the problem we consider finite-amplitude pulsations of rapidly rotating columns. An analysis involving the virial theorem gives an approximate description of adiabatic radial motions. It is shown that nonlinearity lessens the stabilizing influence of angular momentum predicted in a linear stability analysis.
Nouvelles recherches sur les involutions cycliques appartenant à une surface algébrique (seconde note)
Authors: Godeaux Lucien
Published: June 2020

Détermination des systèmes linéaires partiels de courbes tracées sur une surface algébrique composés au moyen d'une involution cyclique n'ayant qu'un nombre fini de points unis symétriques, appartenant à cette surface et faisant partie d'un même système linéaire.
Nouvelles recherches sur les involutions cycliques appartenant à une surface algébrique (troisième note)
Authors: Godeaux Lucien
Published: June 2020

Étude des systèmes linéaires partiels appartenant à une involution cyclique n'ayant qu'un nombre fini de points unis de seconde espèce, sur une surface algébrique, contenus dans un même système linéaire.
On Sheppard's corrections for grouping
Authors: Steyaert Herman
Published: June 2020

The particular way in which a continuous variable is transformed to discrete observed values affects the corrections of Sheppard for grouping.
Chemical instabilities and localized structures in non homogeneous media
Authors: Herschkowitz-Kaufman M. , Platten Jean Karl
Published: June 2020

Le problème de la stabilité des états stationnaires de non-équilibre dans le cas de réactions chimiques se déroulant en milieu inhomogène est étudié à l'aide de la méthode variationnelle du potentiel local. La possibilité de transitions instables est ainsi mise en évidence. L'analyse numérique indique l'existence au-delà de l'instabilité de deux comportements nouveaux : des structures dissipatives spatiales localisées et des ondes chimiques.
Structure d'un point uni d'une involution cyclique appartenant à une surface algébrique (première note)
Authors: Godeaux Lucien
Published: June 2020

Détermination de la structure d'un point uni d'une involution cyclique appartenant à une surface algébrique et de celle du point de diramation correspondant sur une surface image de l'involution.
On the inertial effects induced by a shell of finite thickness
Authors: Lausberg A.
Published: June 2020

Les équations du mouvement de la Relativité Générale, pour une particule-test placée dans le champ d'une couche en rotation, font apparaître des termes d'ordre de grandeur Gω, Gω² et G2²ω², où G est la constante de gravitation de Newton et to la vitesse angulaire de la couche par rapport aux « étoiles fixes ». Le champ de Coriolis induit (d'ordre Gω) est calculé ici dans le cas d'une couche d'épaisseur finie. Il est ensuite démontré que les termes d'ordre Gω² doivent être interprétés, non comme des effets centrifuges, mais plutôt comme des effets gravifiques, au sens de Newton. Les termes centrifuges doivent en fait être d'ordre G²ω². Des solutions à cet ordre ont été proposées récemment par Teyssandier, mais seulement dans les régions vides de matière.

Un premier pas en vue de prolonger ces solutions au travers de la couche est accompli ici, en ce sens que le tenseur d'énergie et des tensions est calculé au sein de la couche. Cette étude fait apparaître un effet de Coriolis induit par la couche en rotation sur ses propres particules. Cet effet de self-inertie pourrait constituer, au moins partiellement, la source de l'effet centrifuge induit.
The solution of the equation of transport for dense fluids
Authors: Allen Peter Murray
Published: June 2020

Les équations générales de transport linéarisées, qui ont. été récemment développées dans le cas d'un fluide dense en présence d'un gradient de vitesse hydrodynamique, sont résolues. Les expressions de la viscosité de cisaillement sont obtenues explicitement. Ces résultats incluent, comme cas particuliers, ceux obtenus par Prigogine, Nicolis et Misguich d'une part et Allen et Cole d'autre part, lesquels correspondent à des hypothèses supplémentaires (et opposées) sur les échelles de temps.