bluuebunny/crossref_metadata_2025 huggingface dataset:
Estimating water residence time distribution in river networks by
boosted regression trees (BRT) model
Authors: Feng Meili , Pusch Martin , Venohr Markus
Published: September 2018

Abstract. In-stream water residence time (WRT) in river networks is a crucial driver for biogeochemical processes in riverine ecosystems. Dynamics of the WRT are critical for understanding and modelling nutrient retention in lakes and rivers, in particular during flood events when riparian areas are inundated. This study illustrates the potential utility of integrating spatial landscape analysis with machine learning statistics to understand the effects of hydrology and geomorphology on WRT in river networks, especially at large scales. We applied the Boosted Regression Trees (BRT) approach to estimate water residence, a promising multi-regression spatial distribution model with consistent cross-validation procedure, and identified the crucial factors of influence. Reach-average WRTs were estimated for the annual mean hydrologic conditions as well as the flood and drought month, respectively. Results showed that the three most contributing factors in shaping the WRT distribution are river discharge (57 %), longitudinal slope (21 %), and the drainage area (15 %). This study enables the identification of key controlling factors of the reach-average WRT and estimation of WRT under varying hydrological conditions. The resulting distribution model of WRT is an easy to apply and sound approach helping to improve water quality modelling at larger scales and water management approaches aiming to estimate nutrient fluxes in river systems.
Assessing the effect of flood restoration on surface–subsurface interactions in Rohrschollen Island (Upper Rhine River – France) using integrated hydrological modeling and thermal infrared imaging
Authors: Jeannot Benjamin , Weill Sylvain , Eschbach David , Schmitt Laurent , Delay Frederick
Published: September 2018

Abstract. Rohrschollen Island is an artificial island of the large Upper Rhine River whose geometry and hydrological dynamics are the result of engineering works during the 19th and 20th centuries. Before its channelization, the Rhine River was characterized by an intense hydro-morphological activity which maintained a high level of biodiversity along the fluvial corridor. This functionality considerably decreased during the two last centuries. Since 2012, a restoration project was launched to reactivate typical alluvial processes, including bedload transport, lateral channel dynamics and surface–subsurface water exchanges. An integrated hydrological model has been applied to the area of Rohrschollen Island to assess the efficiency of the restoration regarding surface and subsurface flows. This model is calibrated using measured piezometric heads. Simulated patterns of water exchanges between the surface and subsurface compartments of the Island are checked against the information derived from thermal infrared imaging. The simulated results are then used to better understand the evolutions of the infiltration/exfiltration zones over time and space and to determine the physical controls of surface–subsurface interactions on the hydrographic network of Rohrschollen Island. The use of integrated hydrological modeling has proven to be an efficient approach to assess the efficiency of restoration actions regarding surface and subsurface flows.
INFERRING ROUTING PREFERENCES OF BICYCLISTS FROM SPARSE SETS OF TRAJECTORIES
Authors: Oehrlein J. , Förster A. , Schunck D. , Dehbi Y. , Roscher R. , Haunert J.-H.
Published: September 2018

Abstract. Understanding the criteria that bicyclists apply when they choose their routes is crucial for planning new bicycle paths or recommending routes to bicyclists. This is becoming more and more important as city councils are becoming increasingly aware of limitations of the transport infrastructure and problems related to automobile traffic. Since different groups of cyclists have different preferences, however, searching for a single set of criteria is prone to failure. Therefore, in this paper, we present a new approach to classify trajectories recorded and shared by bicyclists into different groups and, for each group, to identify favored and unfavored road types. Based on these results we show how to assign weights to the edges of a graph representing the road network such that minimumweight paths in the graph, which can be computed with standard shortest-path algorithms, correspond to adequate routes. Our method combines known algorithms for machine learning and the analysis of trajectories in an innovative way and, thereby, constitutes a new comprehensive solution for the problem of deriving routing preferences from initially unclassified trajectories. An important property of our method is that it yields reasonable results even if the given set of trajectories is sparse in the sense that it does not cover all segments of the cycle network.
DEFINING SEMANTIC LEVELS OF DETAIL FOR INDOOR MAPS
Authors: Chen J.
Published: September 2018

Abstract. One major challenge in creating indoor maps involves defining their levels of detail or LODs. While a consensus has emerged that indoor maps have at least two types of LODs, semantic and geometric, questions remain regarding their nature, their partitioning, and their relationships with each other as well as with other forms of LOD. Since semantics deals with the meanings of things, semantic LODs (SLODs) deal with the definition, classification, and partitioning of mapped entities. Unlike geometric LODs that are amenable to automation, SLODs have a more qualitative nature that defies automation and requires the careful application of human judgment. This paper proposes a framework for organizing semantic LODs by first classifying them based on the tangibility of mapped entities (i.e., intangible open spaces versus tangible physical features comprised of building structures and equipment and furnishings) and then partitioning each class based on the idea of permanence, defined here as an entity’s tendency to remain stationary over time. A cartographic process for integrating SLODs with geometric and appearance LODs is also introduced along with several examples.
SHORT TERM URBAN TRAFFIC FORECASTING USING DEEP LEARNING
Authors: Albertengo G. , Hassan W.
Published: September 2018

Abstract. In today’s world, the number of vehicles is increasing rapidly in developing countries and China and remains stable in all other countries, while road infrastructure mostly remains unchanged, causing congestion problems in many cities. Urban Traffic Control systems can be helpful in counteracting congestion if they receive accurate information on traffic flow. So far, these data are collected by sensors on roads, such as Inductive Loops, which are rather expensive to install and maintain. A less expensive approach could be to use a limited number of sensors combined with Artificial Intelligence to forecast the intensity of traffic at any point in a city. In this paper, we propose a simple yet accurate short-term urban traffic forecasting solution applying supervised window-based regression analysis using Deep Learning algorithm. Experimental results show that is it possible to forecast the intensity of traffic with good accuracy just monitoring its intensity in the last few minutes. The most significant result, in our opinion, is that the machine can generate accurate predictions even with no knowledge of the current time, the day of the week or the type of the day (holiday, weekday, etc).
SMART CITY WEBGIS APPLICATIONS: PROOF OF WORK CONCEPT FOR HIGH-LEVEL QUALITY-OF-SERVICE ASSURANCE
Authors: Noskov A.
Published: September 2018

Abstract. In the frame of smart city initiatives, map-based web applications (WebGIS) are distinguished by the complexity of client-side implementation and high load on web servers. Web-map applications provide non-typical web content usually visualized by JavaScript code. For such applications, higher-level advanced approaches to quality of service (QoS) assessment are required. In this paper, a method based on the estimation of users’ interest in a web page and the information quantity provided by a web page is introduced. In order to implement it, a proof of work (PoW) concept is applied for verification of real users. Moreover, a novel metric is introduced to calculate the information quantity provided by web pages. PoW is used for verification of real users and distinguishing them from bots. Additionally, it can be utilized for balancing of web server load. For monitoring of web pages, an image-based approach is introduced. Web pages are rendered into raster images. A number of metrics describing an image are calculated. This approach allows users to compare and track various web pages, including rich web applications providing complex WebGL content. Several web services utilize the developed solutions. Analysis of harvested data proves the effectiveness of the proposed solution.
DESIGNING PRECINCTS IN THE DENSIFYING CITY – THE ROLE OF PLANNING SUPPORT SYSTEMS
Authors: Gudes O. , Glackin S. , Pettit C.
Published: September 2018

Abstract. Australia’s cities face significant social, economic and environmental challenges, driven by population growth and rapid urbanisation. The pressure to increase housing availability will lead to greater levels of high-density and medium-density stock. However, there is enormous political and community pushback against this. One way to address this challenge is to encourage medium-density living solutions through “precinct” scale development. Precinct-scale development has the potential to include additional hard and soft infrastructure that may offset the perceived negativities of higher densities. As part of Australian research into precinct-scale development, and as part of our broader Smart Cities approach, or more specifically City Analytics approach, new digital planning tools – Envision and ESP – have been developed to support scenario planning and design needs. They utilise a data-driven and scenario planning approach underpinned by Geographic Information System (GIS) functionality.We focus on a case study in the City of Blacktown, Western Sydney, New South Wales, Australia. By 2036 Blacktown is forecast to grow to approximately 500,000 people (an increase of over 30 %) and 180,000 dwellings. Most new dwellings will be delivered through urban infill. The Blacktown master plan promotes higher density housing, mixed employment uses and continued improvements to the public domain. Our study provides a unique opportunity to implement this broad strategy within a specific case and location. Specifically, this paper provides information on how these digital planning tools supported Blacktown planners in identifying, co-designing and implementing a new approach for precinct level planning. It also presents the results of an evaluation of digital-planning tools in the context of the Blacktown case study.
Effectiveness of low-impact development for urban inundation risk mitigation under different scenarios: a case study in Shenzhen, China
Authors: Wu Jiansheng , Yang Rui , Song Jing
Published: September 2018

Abstract. The increase in
impervious surfaces associated with rapid urbanization is one of the main
causes of urban inundation. Low-impact development (LID) practices have been
studied for mitigation of urban inundation. This study used a hydrodynamic
inundation model, coupling SWMM (Storm Water Management Model) and IFMS-Urban
(Integrated Flood Modelling System–Urban), to assess the effectiveness of LID
under different scenarios and at different hazard levels. The results showed that LID
practices can effectively reduce urban inundation. The maximum inundation
depth was reduced by 3 %–29 %, average inundation areas were reduced
by 7 %–55 %, and average inundation time was reduced by
0 %–43 % under the eight scenarios. The effectiveness of LID
practices differed for the three hazard levels, with better mitigation of
urban inundation at a low hazard level than at a high hazard level. Permeable
pavement (PP) mitigated urban inundation better than green roofs (GRs) under
the different scenarios and at different hazard levels. We found that more implementation
area with LID was not necessarily more efficient, and the scenario of
10 % PP+10 % GR was more efficient for the study area than other
scenarios. The results of this study can be used by local governments to
provide suggestions for urban inundation control, disaster reduction, and
urban renewal.
Communicating public avalanche warnings – what works?
Authors: Engeset Rune V. , Pfuhl Gerit , Landrø Markus , Mannberg Andrea , Hetland Audun
Published: September 2018

Abstract. Like many other mountainous countries, Norway has experienced a rapid
increase in both recreational winter activities and fatalities in avalanche
terrain during the past few decades: during the decade 2008–2017,
64 recreational avalanche fatalities were recorded in Norway. This is a
106 % increase from that of the previous decade. In 2013, Norway therefore
launched the National Avalanche Warning Service (NAWS), which provides
avalanche warnings to transport and preparedness authorities and to the
public. Previous studies suggest that avalanche warnings are used extensively
in trip and preparedness planning and have a relatively strong influence on
the decisions people make in order to reduce risk. However, no evaluation
concerning how efficiently the warnings are communicated and understood has
been done to date in Norway. Avalanche warnings communicate complex natural
phenomena with a variable complexity and level of uncertainty about both the
future and the present. In order to manage avalanche risk successfully, it is
fundamental that the warning message can be understood and translated into
practice by a wide range of different user groups. Users with little or no
avalanche competence may need simple information to decide when to stay away
from avalanche terrain, while professional users may need advanced technical
details in order to make their decisions. To evaluate how different modes of
communication are understood, and how efficiently the informational content
is communicated, we designed and implemented a web-based user survey. The
modes of presentation were based on the Varsom.no 2017 version (Varsom.no
being the national portal for natural hazard warnings in Norway). We first
used a panel of 110 experts from NAWS to answer the survey, and used their
answers to establish the indented message of the avalanche warning. We
thereafter received responses from 264 users and compared their answers to
those of the NAWS experts for the different modes of communication. We
developed a method, the comprehension effectiveness score, to test the
comprehension. Our empirical analyses suggest that most users find the
warning service to be useful and well suited to their needs. However, the
effectiveness of a warnings seems to be influenced by the competency of the
user and the complexity of the scenarios. We discuss the findings and make
recommendations on how to improve communication of avalanche warnings.
Weight analysis of dam break risk consequences influencing factors
Authors: Li Zongkun , Li Wei , Ge Wei
Published: September 2018

Abstract. There are numerous influencing factors of the risk consequences of dam break. Scientific and reasonable index system and its weight distribution is one of the key element for comprehensive evaluation of the dam-break risk. Taking into consideration of 20 factors, including hazards, exposure and vulnerability factors, the evaluation index system of the consequences of the dam break risk is constructed. Using the Statistical Cloud Model (SCM) to improve the entropy method, we establish the weight calculation model of the influencing factors of the dam break risk consequences. The results shows that the top 5 factors with the highest weight are risk population, flood intensity, alert time, risk understanding and distance from the dam. Compared to the traditional algebraic weight calculation methods, the result is basically consistent with the algebraic weight distribution, and increases the range by 2.03 times, supporting a more scientific basis for recognizing and evaluating the dam break risk consequences.
New ground ice maps for Canada using a paleogeographic modelling approach
Authors: O'Neill H. Brendan , Wolfe Stephen A. , Duchesne Caroline
Published: September 2018

Abstract. Ground ice melt caused by climate-induced permafrost degradation may trigger significant ecological change, damage infrastructure, and alter biogeochemical cycles. The fundamental ground ice mapping for Canada is now > 20 years old, and does not include significant new insights gained from recent field and remote sensing based studies. New modelling incorporating paleogeography is presented in this paper to depict the distribution of three ground ice types (massive ice and icy sediments, segregated ice, and wedge ice) in northern Canada. The modelling uses an expert-system approach in a geographic information system (GIS), founded in conceptual principles gained from empirically-based research, to predict ground ice abundance in near-surface permafrost. Datasets of surficial geology, deglaciation, paleovegetation, glacial lake and marine limits, and modern permafrost distribution allow representations in the models of paleoclimatic shifts, tree line migration, marine and glacial lake inundation, and terrestrial emergence, and their effect on ground ice abundance. The model outputs are generally consistent with field observations, indicating abundant relict massive ice and icy sediments in the western Arctic, where it has remained preserved since deglaciation in thick glacigenic sediments in continuous permafrost. Segregated ice is widely distributed in fine-grained deposits, occurring in highest abundance in glacial lake and marine sediments. The modelled abundance of wedge ice largely reflects the exposure time of terrain to low air temperatures in tundra environments following deglaciation or marine/glacial lake inundation, and is thus highest in the western Arctic. Holocene environmental changes result in reduced ice abundance where tree line advanced during warmer periods. Published observations of thaw slumps and ice exposures, segregated ice and associated landforms, and ice wedges allow a favourable preliminary assessment of the models, and the results are generally comparable with the previous ground ice mapping for Canada. However, the model outputs are more spatially explicit and better reflect observed ground ice conditions in some regions. Synthetic modelling products that incorporated the previous ground ice information may therefore include inaccuracies. The presented modelling approach is a significant advance in permafrost mapping, but additional field observations and volumetric ice estimates from more areas in Canada are required to improve calibration and validation of small-scale ground ice modelling.
Dislocation and Self-Certainty
Authors: Heyes Cressida J
Published: September 2018

This article summarizes Ami Harbin’s 2016 monograph, Disorientation and Moral Life, which argues that disorientations are an invaluable ethical resource. Harbin offers what she calls a “non-resolvist account of moral agency,” in which non-deliberative and non-decisive action has the potential to be just as morally significant as fully thought-through and conclusive decision-making. It then suggests that Harbin’s moral method provides a useful way of thinking through political inequities in the discipline of Philosophy, and illustrates this with some examples. It highlights three lacunae or possible extensions to the argument: the value but also the complexity of understanding “doubling back” strategies; the ambivalence between psychological and philosophical claims about the value of irresoluteness and the paradoxical nature of being certain of the value of moral uncertainty; and the spatial, temporal, and embodied nature of disorientation.
“Going Viral”: Contagious Agency Through Learned Helpfulness in a Choral Ensemble
Authors: Hogle Lauri A.
Published: September 2018

Through hermeneutic phenomenological study (van Manen, 2015b), I explored the music learning processes of multiage learners in a choral ensemble (aged 6–16) designed as a social constructivist learning environment (Fosnot, 1996; Wiggins, 2015). The multiage structure of the ensemble fostered peer scaffolding, which flourished and became central to the culture of the ensemble. The prevalence of this phenomenon enabled insight into a collaborative learning process and how it supported learners’ construction of musical understanding and musical agency (Wiggins, 2016) of individuals within the group. Emergent themes reflected the presence of phenomena I describe as contagious, “viral,” musical agency, and care/courage, and the key role that emotion played in learning processes. Findings describe a reified community of learned helpfulness (Hogle, 2018), as learners fluidly and dialogically offered their agentive musical selves as teacher-helpers and learner-helpers (Hogle, 2018), focused on shared performance goals within the choral ensemble. Attuned learners provided socially mediated processes of pedagogical tact (van Manen, 2015a) to scaffold individuals’ learning needs, processes, and musical agency. Through this transformative process, ensemble agency, community, and musical performance flourished.
An Analysis of Ratings and Interrater Reliability of Adjudicated Orchestra Festivals
Authors: Mick James P. , Pope David A.
Published: September 2018

The purpose of this study was to identify the influence of school level (middle and high), festival level (district and state), music classification (A, B, C, D, and E), and instrumentation (full and string orchestra) on the overall performance ratings assigned to orchestral performances at large ensemble Music Performance Assessment (MPA) festivals. Data consisted of overall ratings (N = 1,996) assigned at district (n = 1,844) and state level (n = 152) MPA festivals sponsored by the Florida Orchestra Association between 2010 and 2015. Analysis revealed that 94% of all high school orchestras at district and state festivals earned a I/Superior or II/Excellent rating. Logistic regression models revealed: (a) high school orchestras were more likely to earn I/Superior ratings at district festivals than state festivals, (b) middle school orchestras were less likely to earn I/Superior ratings than high school orchestras, and (c) orchestras that performed more difficult repertoire increased their likelihood of earning a I/Superior over ensembles that played easier literature. Festival administrators may use the results of this study to identify specific evaluation trends at adjudicated festivals that can be strengthened.
“El bombo loco”: Sounding Alterity and Populism in Buenos Aires
Authors: O’Brien Michael S.
Published: September 2018

The bombo con platillo, a double-headed bass drum with a mounted cymbal, is a potent icon of murga porteña, a genre of Carnival art from Buenos Aires, Argentina. The instrument also has strong associations with other marginalized popular activities: soccer fandom and Peronist political demonstration. These historical associations alone are not sufficient to account for the drum’s importance, however. This ethnographic account considers the social life of the bombo as an agent with the power to generate effects that are sonic, corporeal, economic, and political in the service of these marginalized popular identities.

El bombo con platillo, un tambor grave de dos parches con un platillo montado, es un ícono potente de la murga porteña, un género de arte carnavalesco de Buenos Aires, Argentina. El instrumento también conlleva asociaciones fuertes con otros circuitos populares y marginales: la hinchada de fútbol y la manifestación política peronista. Sin embargo, estas asociaciones históricas no son del todo suficientes para explicar su importancia. Este análisis etnográfico trata la vida social del bombo como actor que tiene el poder de generar efectos sonoros, corporales, económicos, y políticos, en servicio de estas identidades marginales.
The Cult of Peace on the Athenian Stage during the Peloponnesian War: From Euripides’s Cresphontes to Aristophanes’s Peace and Beyond
Authors: Athanassaki Lucia
Published: September 2018

This paper argues that Euripides in Cresphontes (produced probably in 424 B.C.E.) and Aristophanes in Farmers (423 B.C.E.) and Peace (421 B.C.E.) reflect and promote the plan of the peace enthusiasts in Athens to institute an official cult of the goddess in the city once peace with Sparta was agreed; through investigation of contemporary and later literary and visual evidence (including Aristophanes’s Acharnians and Lysistrata, Thucydides, and Plutarch) it offers an explanation why this plan was not fulfilled till much later, i.e., after the Peace of Timotheus in 374 B.C.E.
Doctors in a Comic Costume: Medical Language and Mass Audience in the Comedy of Menander
Authors: Kazantzidis George
Published: September 2018

This article argues that the medical language in Menander’s Aspis can be understood as both a kind of medical “gibberish” but also as an accurate representation of a professional diagnosis, and that the choice of interpretation is largely dependent on the medical knowledge of the individual audience member. To simply dismiss any instance of comic medical language as nonsensical, assuming that any other alternative would have made it less accessible to the audience and would have compromised the colloquial basis on which popular comedy operates, misses the point entirely; rather, it is better to think that different members in the audience would have been expected to respond to technical jargon in different ways. Seen in this light, medical language is essentially used by Menander as a means of debating the poet’s own linguistic distance from or proximity to different people in the audience: by putting a (fake) doctor on stage—and by making him speak in a strange language which sounds convincing to other characters in the play precisely because it remains elusive, the poet creates an authorial double who tests the linguistic limits of both the internal and the external audience, leaving us to decide how much of his, and Menander’s, (deceptively) nonsensical jargon we are in the position to understand.
pessimus omnium poeta: Canonization and the Ancient Reception of Cicero’s Poetry
Authors: Bishop Caroline
Published: September 2018

This article discusses the ancient reception of Cicero’s poetry and explains why ancient critiques of it were primarily made under the aegis of genre essentialism: the Greek concept that each author was naturally suited to one genre. It argues that these critiques were a direct result of Cicero’s canonization as Rome’s primary prose author, and specifically of his transformation into an allegory for Republican eloquence silenced by tyranny. Because this canonization relied so heavily on the Philippics, in which Cicero discusses mockery of his poetry (2.19–20), it is concluded that, ironically, Cicero himself sowed the seeds for this tradition.
Ethical Questions for Research Ethics: Animal Research in China
Authors: Cao Deborah
Published: September 2018

This article raises a legitimate concern for animals used in research in China. China does not have any anticruelty laws, but there are various regulations concerning the use of animals in research. More scientific experiments using animals are shifting from the West to China, where ethical rules and animal welfare laws are not as stringent as those in Western countries. The article focuses on animals in research in China by outlining the regulatory framework governing such animal use. It also raises ethical issues for Western scientists doing animal research in China.
Factors Influencing Intranet Acceptance in Restaurant Industry: Use of Technology Acceptance Model
Authors: Park Kunsoon , Park Narang , Heo Wookjae
Published: September 2018

This study examines factors influencing the user acceptance of intranets in the restaurant industry. The study uses the application of the technology acceptance model (TAM) in explaining intranet usage in restaurant operations. The TAM is an exceptional model for which to predict system usage and has been successfully applied to numerous technologies. The original model was modified to include two independent variables: organization support and information quality. The survey collected data from restaurants in the United States. The results of the study showed that perceived usefulness was the main factor influencing intranet acceptance, while organization support, information quality, and perceived ease of use were not significant in the regression analysis. The findings indicate perceived usefulness of intranet use requires focus in order to improve communications in restaurant franchise systems.
Examining the Impact of Strategy Management and Information Technology on Organizational Performance of Sharjah Police
Authors: Abdulla AbudlHabib Abdulla Awadh , Al-Dhaafri Hassan
Published: September 2018

The primary aim of this study is to investigate the effects of IT management and strategy management on the performance of organizations. Based on a solid theoretical basis and a thorough literature review, the author developed the study model, with the models adopted being the Resource-Based View of the Firm (RBV), Knowledge-Based View (KBV) and the Innovation theories. The study carried out an analysis of the effects of IT management and strategy management on the performance of organizations. For the purpose of this analysis, three hundred and forty-one (341) questionnaires were distributed to random selected Sharjah Police departments, in Sharjah, UAE. From the total questionnaires distributed, two hundred and forty-five (245) were returned, the data from which was analyzed using SPSS. The results of the analysis showed that IT management and strategy management had a positive and significant effect on organizational performance of Sharjah Police departments. The study recommends the effective implementation of IT management and strategy management for effective and successful performance of Sharjah police departments. The study confirmed the applicability of both the Resource-Based View and the Knowledge-Based View on examining organizational performance.
Of/Of: de alternatieve kwalificatie
Authors: Altena-Davidsen J.G.H.
Published: September 2018

Of/Of: de alternatieve kwalificatie

In het conceptwetsvoorstel voor Boek 4 van het nieuwe Wetboek van Strafvordering (de berechting) wordt het voorstel gedaan om een alternatieve kwalificatie mogelijk te maken. In deze bijdrage wordt, na een uiteenzetting van het geldende recht en de wijziging die het voorstel daarin moet aanbrengen, onderzocht of in de praktijk behoefte bestaat aan de mogelijkheid tot alternatieve kwalificatie. Die behoefte lijkt beperkt te zijn, en zich vooral voor te doen in de context van het gedifferentieerde stelsel van vermogensdelicten en deelnemingsvormen. Deze bijdrage werpt daarom de vraag op of het probleem, en bijgevolg de oplossing daarvan, niet eerder gelegen zijn in het materiële recht dan het strafprocesrecht. Op basis daarvan, alsmede op basis van een korte bespreking van mogelijke bezwaren tegen de alternatieve kwalificatie, wordt de stelling betrokken dat het voorstel nadere doordenking en onderbouwing behoeft.
TESTING BRAKE FLUID WEAR PROCESSES IN COMPLEX CONSTRAINED CONDITIONS
Authors: BĄKOWSKI Henryk , STANIK Zbigniew , KUBIK Andrzej
Published: September 2018

The study determined the effect of increased water content in a brake fluid by measuring its hydration and
boiling temperature and examining the impact of brake fluid wear on the safety and reliability of a braking
system. Within the scope of work, the temperature of the brake discs was determined according to the braking
distance. An experimental bench was set up to determine the boiling point of the hydrated brake fluid. The
position is designed to reflect the operating conditions of intense braking and lead to the boiling of the brake
fluid. A summary of all laboratory and operating tests of the brake fluid tested allowed the minimum braking
distance to be determined after which the brake fluid of varying degrees of hydration (over various operating
periods) could boil beyond the permitted boiling point.
INFLUENCE OF FILLERS ON THE RHEOLOGICAL PROPERTIES OF THEIR COMPOSITIONS WITH LUBRICATING GREASES
Authors: CZARNY Ryszard
Published: September 2018

The paper presents the results of studies on the influence of fillers, introduced into lubricating greases, on
the rheological properties of resultant grease compositions. These fillers were graphite and PTFE powders.
They are added to greases in order to improve their tribological properties. They also affect their rheological
properties, and they mainly change the value of the shear stress in grease during its flow in a lubrication
system. Knowledge of this value is important in designing automated central lubrication systems in which
these compositions may be used. Measurements during experimental tests were performed by means of
a rotary rheometer Rheotest 2.1. Tests were performed on pure lithium and bentonite greases, with the addition
of oxidation and corrosion inhibitors as well as compositions of these greases with different shares of the
above mentioned fillers. These tests were performed by changing the gradient of shearing rate. Test results
have shown that both the kind of grease and the kind of filler introduced into this grease affect the rheological
properties of produced grease compositions.
IDENTIFICATION OF FRICTION CONDITIONS IN HUMAN JOINTS
Authors: RYNIEWICZ Andrzej , RYNIEWICZ Anna
Published: September 2018

The purpose of the paper is to explain the friction conditions and the lubrication mechanism in healthy joints, based on rheological tests of synovial fluid and the identification of structures and the shape of articular surfaces. The tests were performed on cadaver preparations of large lower limp joints: hip, knee, and ankle joints. The analysis included combined experimental activities with the use of modern research and test techniques in the area of viscosity and microscopy as well as diagnostic imaging, image analysis, modelling, and FEM simulation. The tests performed allowed for the analysis of lubrication process which can be described as bioelastohydrodynamic lubrication (BEHL). The most important are viscoelasticity properties of the synovial fluid and the process whereby the external load is taken over by the pressure generated by a set of oil wedges of synovial fluid formed by naturally wavy articular surface. The multi-layer structure of the joints is characterised by variable wavy shape of cartilaginous surfaces and of bone tissue and by the variable wavy thickness of the cartilage.
TRIBOLOGICAL TESTS OF THE NANOMATERIALS USED TO RECONSTRUCT MOLARS AND PREMOLARS WITH THE APPLICATION OF THE DIRECT METHOD
Authors: RYNIEWICZ Wojciech , HERMAN Mariola , RYNIEWICZ Anna M. , BOJKO Łukasz , PAŁKA Paweł , RYNIEWICZ Andrzej , MADEJ Tomasz
Published: September 2018

Physiological abrasion of teeth is a process of gradual loss of the hard tissue of opposite teeth resulting
from age-related natural dental wear. In abrasion, the cusps and their slopes in the jaw and the mandible
become flattened due to the mechanical load applied. The aim of this paper is to carry out a tribological and
microstructural evaluation of modern composite materials used to reconstruct the teeth in the lateral part of the
dental arch. Five light-cured composite materials were selected for tests. The tests involved the coefficient of
friction and resistance to wear in a sliding contact in the presence of artificial saliva and the microstructure of
the external surface of samples before the wear process and in the wear-related damaged area. The test method
applied, which combines a biomechanical analysis of resistance to wear and the analysis of the microstructure
before the wear process and in the wear-related damaged area, makes it possible to evaluate the tribological
properties of composite materials used to reconstruct teeth in the lateral part of the dental arch.
PROPERTIES OF CARBIDE LAYERS PRODUCED BY MEANS OF THE POWDER METHOD AT LOW PRESSURE
Authors: BOGDAŃSKI Bogdan , KASPRZYCKA Ewa , KACPRZYŃSKA-GOŁACKA Joanna
Published: September 2018

The paper presents the results of examinations of materials and tribological properties of chromized carbide layers produced on tool steel by means the powder method, modified by the use of low pressure during the process, for the avoidance of the oxidation of the batch. Investigations of the structure of the layers, the topography of the surface of chromized steel samples, their hardness, Young′s modulus, layers adhesion to steel core and tribological properties were conducted. It was proved that the structure and proprieties of chromized carbide layers produced by means of both methods are similar. However, layers produced with the novel vacuum method have greater thicknesses than layers received with the powder method, at the same process parameters (the time and the temperature). This means that, with the novel vacuum method, one could produce layers at lower temperatures than is possible by means of the traditional pack powder method, which has an essential meaning from the point of view of mechanical proprieties of the steel core.
THE INFLUENCE OF THE LAYERED STRUCTURE OF POLYMER COATINGS ON THEIR EROSIVE RESISTANCE
Authors: KOTNAROWSKA Danuta
Published: September 2018

The paper presents the results of erosive resistance investigation of three-layer epoxy coating systems with different compositions of surface layers. This layer was modified with glass microspheres or nanoparticles of aluminium trioxide or silica. The highest erosive resistance, in the whole thickness range of examined epoxy coatings, was revealed by coating systems with a surface layer (top coat) modified using nanoparticles of aluminium trioxide. Similar but slightly lower erosive resistance was reported in the case of surface layer modification with nanoparticles of silica use. High erosive resistance of coating systems modified with nanoparticles results from their structure reinforcement by nanoparticles that seal nanopores generated during the process of coating constitution. The lowest erosive resistance was observed in the case of systems with a surface layer modified using glass microspheres. This results from high brittleness of glass microspheres, which is evident during the coating surface bombardment with alundum particles. The paper demonstrates the methods for the analysis of the interaction between lubricant and steel substrate and presents the obtained results. The samples to be tested were commercially available greases as well as greases developed for the purpose of this research, containing a known amount of adhesion additives. Due to the lack of normalized methods, the authors applied indirect methods based on the analysis of the peel resistance and the resistance to variable shearing rates. The obtained results reveal that there is a possibility to apply the proposed methods for the comparative assessment of interactions between the grease and steel substrate.
EVALUATION OF SELECTED PROPERTIES OF A SURFACE LAYER
AFTER MILLING USING INSERTS WITH DIFFERENT COATINGS
Authors: MAJ Piotr , MIKO Edward
Published: September 2018

The article presents a comparison of results of measurements of the geometrical structure of milled surfaces
with inserts with different coatings. The study was done on a vertical milling centre. The first step was to
determine the properties of milled surfaces using new inserts. For this purpose, an optical apparatus was used.
The samples were then subjected to continuous treatment. Upon completion of the declared quantities of
machining cycles, these surfaces were analysed. This allowed us to determine the influence of the coating of
the inserts on the surface layer of milled surfaces continuously.
THE ANALYSIS OF HYDRODYNAMIC PRESSURE DISTRIBUTION AND LOAD CARRYING CAPACITY IN THE GAP OF SLIDE JOURNAL BEARINGS WITH MICRO-GROOVES
Authors: MISZCZAK Andrzej
Published: September 2018

The purpose of this paper is to analyse the distribution of hydrodynamic pressure, load carrying capacities, and friction force in the gap of the slide bearing on account of the type, number, and size of micro-grooves on the surface of the sleeve. It was assumed that micro-grooves were distributed equally on the circumference of the sleeve as well as parallel to its axis. Micro-bearings with micro-grooves are more and more often utilized in the technical applications, e.g., in HDD disks or in computer fans. It is advisable to carry out a numerical analysis on the influence of the number and the size of micro-grooves on the value of the basic flow parameters in the slide micro-bearing. A laminar flow of lubricating fluid and an isothermal model of the lubrication of the slide bearing was used for the analysis. A classical Newtonian model was applied as the constitutive equation. A cylindrical slide bearing with the finished length and smooth sleeve, and a full wrap angle was used for the research. The density and thermal conductivity of the oil were considered to be constant in the thin film of oil. The results of measurements of shape and sizes of micro-grooves in real micro-slide bearings were presented by the author in the previous publications. The results of that research are used at present to determine the preliminary assumptions concerning the shape and the size of the micro-grooves. The results obtained in the research show the minor influence of micro-grooves on the value of the friction force and a few percentages rate influence of micro-grooves on the value of load carrying capacity.
MODELLING AND ANALYSIS OF ROTATING SYSTEMS WITH GAS FOIL BEARINGS UNDER TRANSIENT OPERATING CONDITIONS
Authors: ŻYWICA Grzegorz , BOGULICZ Małgorzata , BAGIŃSKI Paweł
Published: September 2018

Gas foil bearings are on the cutting edge of bearing systems that spread worldwide. Although it is a common practice to apply such systems to high-speed fluid-flow machinery, their modelling and analysis still pose a number of problems. This article describes the methodology used to assess dynamic properties of a rotor-bearings system supported by foil bearings. Particularly close attention has been paid to the system operation in a transitional state during which a gaseous lubricating film is formed. The conception for the description of the rotor support characteristics was implemented in a computer program that is still under development. The approach that has been taken makes it possible to analyse the system properties throughout a whole range of rotational speeds. Another approach used in the past enabled for analyses of the dynamic performance of rotors, but only on the condition that bearing operation is correct (i.e. only fluid friction in bearing is present). The new model allows for much broader analyses of bearings operation, as confirmed by the obtained results. The article discusses exemplary results of analyses and shows a way one can assess the dynamic properties of rotating machinery equipped with foil bearings even when analysed under transient operating conditions.
ATTEMPT AT EVALUATING THE INFLUENCE OF BENDING STRESS ON SHAFT WEAR PROCESSES IN WATER LUBRICATED SLIDING BEARING WITH A RUBBER BUSHING
Authors: PIĄTKOWSKA Ewa , LITWIN Wojciech
Published: September 2018

Water lubricated bearings find increasingly wide application in shipbuilding or the hydropower industry, with the popularity stemming from their numerous advantages. Unfortunately, as it turns out, water lubricated bearings do not always meet expectations, because, on occasion, they become subject to intense, premature wear, which requires costly repair. One of the still unexplained phenomena is the process of excessive bearing wear, in particular, that of shaft journal co-working with rubber bushings. The research goal was to evaluate the influence of shaft bending stress on the degree of its wear. Experimental tests were carried out on a purpose-designed test stand. The results of the first test series confirmed that the shaft bending stresses do have impact on the magnitude of wear.
SCUFFING WEAR OF THE TRIBOLOGICAL PAIRS UNDER OSCILLATORY MOTION
Authors: GUZOWSKI Stanisław , ZAJĄC Grzegorz , KACZOR Grzegorz
Published: September 2018

The surfaces of the friction pairs in oscillatory motion are exposed to the complex wear processes. Scuffing is a specific wear process, which comprises abrasive and adhesive wear. This paper presents the results of the preliminary scuffing tests, conducted on the T-05 test machine under oscillatory motion in the line contact. The results obtained from the tests confirmed the high probability of the scuffing occurrence under the assumed tests conditions. This is the basis for the planning of further research in this area.
THE INFLUENCE OF DIFFERENT METHODS OF MILLING A ROUND PIN ON THE PROPERTIES OF SURFACE LAYER USING VERTICAL MILLING CENTER
Authors: MAJ Piotr , MIKO Edward
Published: September 2018

The aim of the article was to show how different strategies for making a round pin influence the properties of the surface layer. Measurements will be made of the circular interpolation and accuracy of movement of the rotary axis. The first strategy was to make circular interpolation using a work X and Y-axis. The second embodiment of the method is presented using the rotational C-axis, while the third method covered the execution of the round pin in the implementation of circular interpolation X- and Y-axes and the displacement of the rotary C-axis. Thus, the formed samples were subjected to measurement of surface roughness. The analysis led to showing how different strategies affect the processing properties of the surface layer around the pins.
THE ANALYSIS OF THE SELECTED PROCESSES OF THERMO-CHEMICAL HEAT TREATMENT OF 20MnCr5 STEEL IN THE CONTEXT OF ABRASIVE WEAR
Authors: TARASIUK Wojciech , LISZEWSKI Mariusz , KRUPICZ Bazyli , KASPRZYCKA Ewa
Published: September 2018

This paper presents the results of tribological tests performed on a T-11 pin-on-disc type, which made it possible to determine the intensity of abrasive wear of steel 20MnCr5 subjected to selected thermo-chemical heat treatments. The tested steel, after the hardening and tempering process, is characterized by high endurance parameters and is used on heavily loaded machine parts. It is frequently used for elements subjected to intense abrasion. The analysis involved the following: carburizing, boronizing, and various methods of diffusion chromizing. For large loads, it is advisable to apply boronizing or carburizing with hardening. Chrome plating entails a very thin layer of increased hardness, which is characterised by a low abrasive wear resistance at high loads.
AN EXAMINATION OF OIL FILM THICKNESS IN A BALL-ON-DISC ASSEMBLY
Authors: GAŁDA Lidia
Published: September 2018

The results of oil film thickness investigations in non-conformal contact in sliding pairs with modified surfaces are presented in the article. The investigations were realized on a ball-on-disc instrument with colorimetric interferometry. Balls were made from 100Cr6 steel of hardness 60–62 HRC. The diameter of balls was 19.05 mm. The tests were carried out at the applied loads of 20 N and 30 N. The glass disc rotated at speeds from 0.1 m/s to 0.2 m/s. At the highest speed (0.2 m/s) the highest maximum value of the oil film thickness of 217 nm was obtained. At 0.2 m/s, the oil film thickness was up to 82% greater than at 0.1 m/s. At 0.1 m/s the maximum oil film thickness values were 100–157 nm. The greatest maximum values of the oil film thickness were received by balls with the smaller surface height application in all of the studied cases.