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Tytuł:
The Proper Diameter of a Graph
Autorzy:
Coll, Vincent
Hook, Jonelle
Magnant, Colton
McCready, Karen
Ryan, Kathleen
Powiązania:
https://bibliotekanauki.pl/articles/32062335.pdf
Data publikacji:
2020-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
diameter
properly connected
proper diameter
Opis:
A proper edge-coloring of a graph is a coloring in which adjacent edges receive distinct colors. A path is properly colored if consecutive edges have distinct colors, and an edge-colored graph is properly connected if there exists a properly colored path between every pair of vertices. In such a graph, we introduce the notion of the graph’s proper diameter—which is a function of both the graph and the coloring—and define it to be the maximum length of a shortest properly colored path between any two vertices in the graph. We consider various families of graphs to find bounds on the gap between the diameter and possible proper diameters, paying singular attention to 2-colorings.
Źródło:
Discussiones Mathematicae Graph Theory; 2020, 40, 1; 107-125
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Degree-Diameter Problem for Outerplanar Graphs
Autorzy:
Dankelmann, Peter
Jonck, Elizabeth
Vetrík, Tomáš
Powiązania:
https://bibliotekanauki.pl/articles/31341627.pdf
Data publikacji:
2017-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
outerplanar
diameter
degree
degree-diameter problem
distance
separator theorem
Opis:
For positive integers $ \Delta $ and $ D $ we define $ n_{ \Delta, D } $ to be the largest number of vertices in an outerplanar graph of given maximum degree $ \Delta $ and diameter $D$. We prove that $n_{ \Delta , D} = \Delta^{D/2} + O ( \Delta^{ D/2 -1 } ) $ if $D$ is even, and $ n_{ \Delta, D} = 3 \Delta^\frac{D−1}{2} + O (\Delta^{ \frac{D−1}{2}−1 } ) $ if $D$ is odd. We then extend our result to maximal outerplanar graphs by showing that the maximum number of vertices in a maximal outerplanar graph of maximum degree $ \Delta $ and diameter $D$ asymptotically equals$ n_{ \Delta , D }.
Źródło:
Discussiones Mathematicae Graph Theory; 2017, 37, 3; 823-834
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of the effect of size of the umbilical ring on the risk of umbilical hernia complication in children
Autorzy:
Emeka, Chukwubuike Kevin
Chikaodili, Eze Thaddeus
Powiązania:
https://bibliotekanauki.pl/articles/2049116.pdf
Data publikacji:
2022-03-30
Wydawca:
Uniwersytet Rzeszowski. Wydawnictwo Uniwersytetu Rzeszowskiego
Tematy:
complications
diameter
risk
Opis:
Introduction and aim. Assessment of risk of complications in umbilical hernia is important. The aim of this study was to evaluate the effect of size of the umbilical ring on the risk of complication occurring in umbilical hernia. Material and methods. This was a prospective study of children who had umbilical hernia repair for symptomatic umbilical hernia. Using Vernier caliper, the umbilical ring diameter (URD) was measured at surgery and the patients were divided into 2 groups. Group A had URD of less than of 15 millimeter (mm) and group B patients had URD of 15 mm and above. The 2 groups were compared. Results. Thirty two cases were evaluated. Their mean age was 42 months. All the patients had umbilical pain. Twenty six (81.3%) patients had URD of less than 15 mm (group A) whereas 6 (18.7%) patients had URD of greater or equal to 15 mm (group B). Group A patients had a mean URD of 12.1±3.4 mm whereas group B patients had a mean URD of 30.5±5.0 mm (p=0.001). Conclusion. Children who have URD of less than 15 mm are at a higher risk of developing umbilical hernia complications.
Źródło:
European Journal of Clinical and Experimental Medicine; 2022, 1; 75-79
2544-2406
2544-1361
Pojawia się w:
European Journal of Clinical and Experimental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The dynamics of the Taxus baccata L. population and the factors affecting its regeneration in the Jasień Nature Reserve
Autorzy:
Bujoczek, L.
Bujoczek, M.
Powiązania:
https://bibliotekanauki.pl/articles/2078292.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
English yew
seedlings
saplings
diameter increment
diameter distribution
mortality
Opis:
Taxus baccata L. is a relict plant and has a scattered distribution in the entire species range. Yew regeneration may be affected by moisture conditions and tree stand characteristics – variables which change over time and which have not been sufficiently researched to date. The present study determined the size structure of yews, causes of yew mortality, the effects of tree stand characteristics and habitat conditions on yew diameter increment at breast height, the density of yew seedlings and saplings, and the likelihood of yew seedling occurrence. The study was conducted in central Poland, on 22 permanent sampling plots. The paper presents data col- lected in 2017 with reference to previous studies on these plots from 2001 and 2007. Stand volume, basal area, number of trees, canopy cover, and type of forest site were established for the tree layer. Saplings and shrubs were counted. Finally, the parameters determined for yew seedlings included density and percentage of individuals damaged by browsing, as well as soil moisture and percentage cover of herbaceous vegetation in the nearest neighborhood. In 2017, yew density in the tree layer was 70 individuals/ha, having increased by 15 individuals/ha over 16 years. During that period, 6.4 individuals/ha died in that layer. The predominant cause of yew mortality was wind. In the period 2007–2017, the mean diameter increment at breast height was 2.2 mm/year, and indicated a weak relationship only with tree diameter at the beginning of the studied period (R2 = 0.06). In 2017, the mean density of yew saplings and seedlings was 55 individuals/ha and 1005 individuals/ha, re- spectively. Two independent variables were found to be significant in the model of yew seedling occurrence: presence of mature yews on the sampling plot and soil moisture. The condition of the studied yew population is satisfactory, especially in the less moist areas. The number of seedlings is acceptable, but more active protection should be considered due to the scarcity of yew sap- lings. This is all the more important as seed-producing mature yews tend to die as a result of exposure to strong winds and periodic local flooding.
Źródło:
Dendrobiology; 2018, 80; 24-36
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Minimum Edge Cuts in Diameter 2 Graphs
Autorzy:
Bickle, Allan
Schwenk, Allen
Powiązania:
https://bibliotekanauki.pl/articles/31343375.pdf
Data publikacji:
2019-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
edge connectivity
diameter
Opis:
Plesnik proved that the edge connectivity and minimum degree are equal for diameter 2 graphs. We provide a streamlined proof of this fact and characterize the diameter 2 graphs with a nontrivial minimum edge cut.
Źródło:
Discussiones Mathematicae Graph Theory; 2019, 39, 2; 605-608
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Further results on radial graphs
Autorzy:
Kathiresan, Kumarappan
Marimuthu, G.
Powiązania:
https://bibliotekanauki.pl/articles/744513.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
radius
diameter
radial graph
Opis:
In a graph G, the distance d(u,v) between a pair of vertices u and v is the length of a shortest path joining them. The eccentricity e(u) of a vertex u is the distance to a vertex farthest from u. The minimum eccentricity is called the radius of the graph and the maximum eccentricity is called the diameter of the graph. The radial graph R(G) based on G has the vertex set as in G, two vertices u and v are adjacent in R(G) if the distance between them in G is equal to the radius of G. If G is disconnected, then two vertices are adjacent in R(G) if they belong to different components. The main objective of this paper is to characterize graphs G with specified radius for its radial graph.
Źródło:
Discussiones Mathematicae Graph Theory; 2010, 30, 1; 75-83
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on bubble characteristics of flotation column in hematite reverse cationic flotation process
Autorzy:
Wang, Weizhi
Han, Jikang
Powiązania:
https://bibliotekanauki.pl/articles/1450070.pdf
Data publikacji:
2020
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
column flotation
bubble generator
GE-609
circularity
bubble diameter
bubble Sauter diameter
Opis:
In the self-designed flotation column simulation system, the foaming characteristics of the micro-bubble countercurrent contact flotation column used in the hematite cation column flotation process are systematically studied. The objective of this study is to investigate the bubble generation by a bubble generator in the flotation column. The bubble image was obtained by the high-speed camera recorder, and the bubble diameter was calculated and analyzed by image processing software. The distribution characteristics of the bubble size under different aeration conditions and with different reagent concentrations were investigated. The results show that as the aeration increases, the average diameter bubbles increases, the bubble size distribution changes from narrow to wide, and the number of small bubbles decreases. The cationic collector GE-609 can change the bubble shape. As the concentration increases, the bubble shape gradually changes from an irregular shape to a standard spherical shape. When the concentration of GE-609 exceeds 2.5 mg/dm3, the average circularity C of the bubbles in the bubble group stabilizes at 1, and the increase in concentration no longer changes the bubble shape. GE-609 also has an efficient foaming effect, as the concentration increases, the bubble diameter distribution changes significantly, the proportion of small bubbles increases, and the proportion of large bubbles decreases significantly. When the critical concentration is exceeded, the bubble diameter distribution probability density peak width no longer changes significantly. Compared with the two types of alcohol foaming agents, GE-609 produces a bubble Sauter diameter close to that of 2-octanol and slightly lower than terpineol.
Źródło:
Physicochemical Problems of Mineral Processing; 2020, 56, 1; 64-75
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Minimum Harmonic Index for Unicyclic Graphs with Given Diameter
Autorzy:
Zhong, Lingping
Powiązania:
https://bibliotekanauki.pl/articles/31342329.pdf
Data publikacji:
2018-05-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
harmonic index
unicyclic graphs
diameter
Opis:
The harmonic index of a graph $G$ is defined as the sum of the weights \( \tfrac{2}{d(u)+d(v)} \) of all edges uv of G, where $d(u)$ denotes the degree of a vertex $u$ in $G$. In this paper, we present the minimum harmonic index for unicyclic graphs with given diameter and characterize the corresponding extremal graphs. This answers an unsolved problem of Zhu and Chang [26].
Źródło:
Discussiones Mathematicae Graph Theory; 2018, 38, 2; 429-442
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of super-radial graphs
Autorzy:
Kathiresan, K.M.
Marimuthu, G.
Parameswaran, C.
Powiązania:
https://bibliotekanauki.pl/articles/30148721.pdf
Data publikacji:
2014-11-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
radius
diameter
super-radial graph
Opis:
In a graph G, the distance d(u, v) between a pair of vertices u and v is the length of a shortest path joining them. The eccentricity e(u) of a vertex u is the distance to a vertex farthest from u. The minimum eccentricity is called the radius, r(G), of the graph and the maximum eccentricity is called the diameter, d(G), of the graph. The super-radial graph R*(G) based on G has the vertex set as in G and two vertices u and v are adjacent in R*(G) if the distance between them in G is greater than or equal to d(G) − r(G) + 1 in G. If G is disconnected, then two vertices are adjacent in R*(G) if they belong to different components. A graph G is said to be a super-radial graph if it is a super-radial graph R*(H) of some graph H. The main objective of this paper is to solve the graph equation R*(H) = G for a given graph G.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 4; 829-848
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Changes in pasta properties during cooking and short-time storage
Autorzy:
Biernacka, B.
Dziki, D.
Miś, A.
Rudy, S.
Krzykowski, A.
Polak, R.
Różyło, R.
Powiązania:
https://bibliotekanauki.pl/articles/2082561.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:
pasta
diameter
texture
cooking
storage
Opis:
The fundamental aim of this research was to study changes in the physical properties of spaghetti during cooking and after the first hour of storage. In addition, the research evaluated the cooking properties of pasta. For testing purposes, eight samples of spaghetti, produced using semolina and common wheat flour, were used. After cooking, the samples of spaghetti were stored for 2, 5, 10, 20, 30, 40, 50 and 60 min. After storage, the samples of cooked spaghetti were cut, and both the cutting force (hardness) and the cutting energy (firmness) of the samples were determined. It was found that, after storage, the cutting force and energy of cooked pasta decreased, in average terms, from 1.0 to 0.44 N and from 0.84 to 0.43 mJ, respectively. The statistical analysis showed a significant correlation between the storage time and the textural parameters of pasta. The hardness and firmness of pasta, which was al dente after cooking, were found to decrease about twice during storage, as a result of water migration. The hardness of pasta stabilised after 50 min of the storage of cooked spaghetti. Moreover, the obtained data revealed that the diameter increase index of spaghetti could indicate the quality of pasta.
Źródło:
International Agrophysics; 2019, 33, 3; 323-330
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On the diameter of dot-critical graphs
Autorzy:
Mojdeh, D. A.
Mirzamani, S.
Powiązania:
https://bibliotekanauki.pl/articles/255186.pdf
Data publikacji:
2009
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
dot-critical graph
domination
diameter
Opis:
A graph G is k-dot-critical (totally k-dot-critical) if G is dot-critical (totally dot-critical) and the domination number is k. In the paper [T. Burtona, D. P. Sumner, Domination dot-critical graphs, Discrete Math, 306(2006), 11-18] the following question is posed: What are the best bounds for the diameter of a k-dot-critical graph and a totally k-dot-critical graph G with no critical vertices for k ≥ 4? We find the best bound for the diameter of a k-dot-critical graph, where k ∈ {4, 5, 6} and we give a family of k-dot-critical graphs (with no critical vertices) with sharp diameter 2k - 3 for even k ≥ 4.
Źródło:
Opuscula Mathematica; 2009, 29, 2; 165-175
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prognostic Crown Diameter equations for a Mixed Species Plantation in Southern Nigeria
Autorzy:
Buochuama, A.
Oyebade, B. A.
Powiązania:
https://bibliotekanauki.pl/articles/1113007.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
crown
crown diameter
mixed species plantation
model
Opis:
The dimension of a tree crown has an apparent effect on and is strongly linked with the growth of the tree and its diverse parts. Crown information is an important part of numerous growth and yield models. Hence, empirical predictive equations for crown diameter of a mixed species plantation in Southern Nigeria were developed and evaluated in this study. In studying this phenomenon, total enumeration of the selected species in the mixed species plantation was carried out. Moreover, major growth attributes of 185 trees of six species, namely; Khaya ivorensis, Entandrophragma angolense, Terminalia ivorensis, Tectona grandis, Treculia africana and Mansonia altissima were measured and estimated using mensurational methods. Descriptive, correlation, regression and residual analyses were then applied to the quantitative data obtained from the mixed species plantation. For all the species, the best adjudged model with the best fit indices was Ln(cd) = Ln(b0) + b1·CPA·dbh, R2 = 0.936, SEE = 0.037; an indication of parsimonious potential of a predictive exponential model. This paper, therefore, revealed the possibilities of predicting crown diameter for a mixed species plantation in Nigeria with ample prospects for sustainable planning and management decisions that are relevant for any mixed species plantation.
Źródło:
World News of Natural Sciences; 2018, 16; 117-129
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Smallest Regular Graphs of Given Degree and Diameter
Autorzy:
Knor, Martin
Powiązania:
https://bibliotekanauki.pl/articles/30147224.pdf
Data publikacji:
2014-02-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
regular graph
degree/diameter problem
extremal graph
Opis:
In this note we present a sharp lower bound on the number of vertices in a regular graph of given degree and diameter.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 1; 187-191
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A reduction of the Graph Reconstruction Conjecture
Autorzy:
Monikandan, S.
Balakumar, J.
Powiązania:
https://bibliotekanauki.pl/articles/30148259.pdf
Data publikacji:
2014-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
reconstruction
diameter
geodetic graph
interval-regular graph
Opis:
A graph is said to be reconstructible if it is determined up to isomorphism from the collection of all its one-vertex deleted unlabeled subgraphs. Reconstruction Conjecture (RC) asserts that all graphs on at least three vertices are reconstructible. In this paper, we prove that interval-regular graphs and some new classes of graphs are reconstructible and show that RC is true if and only if all non-geodetic and non-interval-regular blocks G with diam(G) = 2 or diam(G) = diam(Ḡ) = 3 are reconstructible.
Źródło:
Discussiones Mathematicae Graph Theory; 2014, 34, 3; 529-537
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Network Function Virtualization: Mitigating the Impact of VoLTE on the Policy and the Charging System
Autorzy:
Jouihri, Y.
Guennoun, Z.
Chagh, Y.
Zahi, D.
Powiązania:
https://bibliotekanauki.pl/articles/307932.pdf
Data publikacji:
2016
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
NFV
policy diameter signaling
policy management
VoLTE
Opis:
Needless to say that telecommunications’ operators are showing increasing interests toward solving the dilemma of optimizing network resources while offering state-of-the-art quality of service. Recently, operators have shown an increasing interest to investigate solutions for better control on network utilization, service usage and monetization. They also noticed a significant growth in Diameter signaling and more specifically in signaling related to policy management. A massive introduction of Voice over LTE (VoLTE) service will have a significant impact on the systems handling policy signaling, as VoLTE will reshape the landscape of Long Term Evolution (LTE) policies and completely change the way policy management works. However, this massive approach is meant to provide significant competitive advantages for operators offering LTE services and still require circuit-switched network to provide voice service. The biggest challenge for those operators is to find an appropriate solution, scalable enough to handle the unpredictable growth of Diameter signaling. In this paper, a model, based on Network Function Virtualization (NFV) technology is proposed, able to address the challenges of massively introducing VoLTE, without impacting existing services and without jeopardizing current revenues. In presented approach, the standard VoLTE call flows, referenced user’s behavior and latest experiments’ results on NFV technology are used.
Źródło:
Journal of Telecommunications and Information Technology; 2016, 2; 66-76
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An upper bound for graphs of diameter 3 and given degree obtained as abelian lifts of dipoles
Autorzy:
Vetrík, Tomás
Powiązania:
https://bibliotekanauki.pl/articles/743521.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
degree and diameter of a graph
dipole
Opis:
We derive an upper bound on the number of vertices in graphs of diameter 3 and given degree arising from Abelian lifts of dipoles with loops and multiple edges.
Źródło:
Discussiones Mathematicae Graph Theory; 2008, 28, 1; 91-96
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Radio number for some thorn graphs
Autorzy:
Marinescu-Ghemeci, Ruxandra
Powiązania:
https://bibliotekanauki.pl/articles/744574.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
multilevel distance labeling
radio number
caterpillar
diameter
Opis:
For a graph G and any two vertices u and v in G, let d(u,v) denote the distance between u and v and let diam(G) be the diameter of G. A multilevel distance labeling (or radio labeling) for G is a function f that assigns to each vertex of G a positive integer such that for any two distinct vertices u and v, d(u,v) + |f(u) - f(v)| ≥ diam(G) + 1. The largest integer in the range of f is called the span of f and is denoted span(f). The radio number of G, denoted rn(G), is the minimum span of any radio labeling for G. A thorn graph is a graph obtained from a given graph by attaching new terminal vertices to the vertices of the initial graph. In this paper the radio numbers for two classes of thorn graphs are determined: the caterpillar obtained from the path Pₙ by attaching a new terminal vertex to each non-terminal vertex and the thorn star $S_{n,k}$ obtained from the star Sₙ by attaching k new terminal vertices to each terminal vertex of the star.
Źródło:
Discussiones Mathematicae Graph Theory; 2010, 30, 2; 201-222
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Riverbank Stability Due to Bamboo Vegetation in Walanae River, South Sulawesi, Indonesia
Autorzy:
Pertiwi, Nurlita
Rauf, Bakhrani Abdul
Lullulangi, Mithen
Powiązania:
https://bibliotekanauki.pl/articles/1955563.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
slope
diameter
weight of bamboo
Walanae river
Opis:
Bamboo vegetation is an endemic plant in Indonesia that grows on riverbanks. These plants have the potential to increase shear resistance due to the bond between the roots to the soil. However, an increase in plant weight due to its growth causes additional loads of soil. The condition triggers the release of soil on the slopes and causes riverbank sliding. Therefore, in developing the riparian ecological function, it is necessary to maintain the plants without neglecting the risk of physical damage to the river. This study aimed to estimate the risk of riverbank sliding due to the presence of bamboo plants by utilizing the bamboo vegetation conditions on the Walanae River. It was carried out on the 42.4 km riverbank in the middle area of Walanae watershed. The researchers selected 46 clumps of parring bamboo (Gigantochloa atter) as an endemic bamboo in this area and growing in the riverbank. The diameter of the bamboo trunk is the basis for an estimate of the weight of the bamboo clump. Furthermore, a numerical analysis was carried out by taking into account the load and shear resistance on the slope, including the weight of the plant. The research results indicated that bamboo is feasible to be applied for riverbank protection using the soil bioengineering method. The bamboo weight, which is indicated by the number of poles and diameter, significantly affects the stability of the slope. Therefore, the prevention of rising weight by harvesting method is critical to consider in riverbank protection.
Źródło:
Journal of Ecological Engineering; 2021, 22, 9; 176-184
2299-8993
Pojawia się w:
Journal of Ecological Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Usage of an empirical equation for determination of mean sediment diameter in beds of small mountain rivers
Autorzy:
Lenar-Matyas, A.
Wolak, A.
Powiązania:
https://bibliotekanauki.pl/articles/101506.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Infrastruktura i Ekologia Terenów Wiejskich PAN
Tematy:
mean sediment diameter
empirical formula
check dam
Opis:
Knowledge of properties of materials deposited in beds of small reservoirs is important, as it can be used for a range of analytic works, concerning river rehabilitation and river management and other similar undertakings. Usually the one property - the d50 value can be obtained using in-situ measurements using sieves but in most cases of preliminary, large scale research may not be feasible. In this paper the Osuch empirical formula for determination of standard sediment grain sizes of d50 is presented. Besides the original formula an improved method of assessing of the slope value for that formula is proposed, which may greatly improve the usefulness of the original, unmodified method. The calculation results are then compared with the in-situ measurements done on many samples taken from the Trzebuńka dam reservoir. The dam was recently partially removed and partially rebuilt, so there was an unique and easy access to wide strata of different layers of sediments, accumulated across many years of dam operation in the exposed bed of partially emptied reservoir. Additionally, the Ratomski formula for riverbed slope determination near dams was used as a reference. The mentioned methods taken together can be used for preliminary analysis before significant works are to be done. The results are quite encouraging and can be a starting point for further method refinement.
Źródło:
Infrastruktura i Ekologia Terenów Wiejskich; 2017, IV/2; 1513-1527
1732-5587
Pojawia się w:
Infrastruktura i Ekologia Terenów Wiejskich
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The eco-hydraulics base as flood mitigation to overcome erosion and sedimentation problems: A case study in the Lae Kombih River, Indonesia
Autorzy:
Ziana, Ziana
Azmeri, Azmeri
Yulianur, Alfiansyah
Meilianda, Ella
Powiązania:
https://bibliotekanauki.pl/articles/2174304.pdf
Data publikacji:
2022
Wydawca:
Instytut Technologiczno-Przyrodniczy
Tematy:
eco-hydraulics
erosion
riverbank
sedimentation
vegetation diameter
Opis:
Erosion and sedimentation have a very big influence on flooding. Floods are strongly influenced by land use and population activities that change the river’s physical condition, including erosion and sedimentation. The river upstream was very steep, and the downstream was narrowing and meandering with high rainfall recorded. This study analyses erosion, sedimentation, and its handling using the eco-hydraulic base. The method involves input rainfall data, river hydraulics, land use, watershed area, and land cover. The analysis of hydrology, hydraulics, land use, flood discharge, and eco-hydraulic, inundation height, vegetation diameter, velocity reduced, and riverbank width measured in five bridges cross-sections along the river. The eco-hydraulic compares the width of existing riverbanks and design, high inundation, and the vegetation diameter to minimise flood discharge. Erosion in the right cliff is 22.73% and the left cliff is 37.04%, land erosion was 225.83 Mg∙ha-1∙year -1. The river’s bottom is formed by rocks of 0.18-1.30 mm. The plantation land used around the Lae Kombih River grows mainly an oil palm with a diameter of 0.5-0.7 m. The riverbank design on 100 m for vegetation diameter of 0.1-1.0 m can retain flood discharge for five years return period up to 72.3%, resulting in discharge of 112.04209.43 m3∙s-1. The largest erosion and sedimentation on the river border is Dusun Silak, so it is recommended to plant Vetiveria zizanioides, Ipomoea carnea and Bambusoideae. An inundation height of 0.9 m can be recommended to design an embankment to be used as flood mitigation.
Źródło:
Journal of Water and Land Development; 2022, 55; 229--239
1429-7426
2083-4535
Pojawia się w:
Journal of Water and Land Development
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization Results for the L(2, 1, 1)-Labeling Problem on Trees
Autorzy:
Zhang, Xiaoling
Deng, Kecai
Powiązania:
https://bibliotekanauki.pl/articles/32031843.pdf
Data publikacji:
2017-08-01
Wydawca:
Uniwersytet Zielonogórski. Wydział Matematyki, Informatyki i Ekonometrii
Tematy:
tree
diameter
L(2, 1, 1)-labeling
Opis:
An L(2, 1, 1)-labeling of a graph G is an assignment of non-negative integers (labels) to the vertices of G such that adjacent vertices receive labels with difference at least 2, and vertices at distance 2 or 3 receive distinct labels. The span of such a labelling is the difference between the maximum and minimum labels used, and the minimum span over all L(2, 1, 1)-labelings of G is called the L(2, 1, 1)-labeling number of G, denoted by λ2,1,1(G). It was shown by King, Ras and Zhou in [The L(h, 1, 1)-labelling problem for trees, European J. Combin. 31 (2010) 1295–1306] that every tree T has Δ2(T) − 1 ≤ λ2,1,1(T) ≤ Δ2(T), where Δ2(T) = maxuv∈E(T)(d(u) + d(v)). And they conjectured that almost all trees have the L(2, 1, 1)-labeling number attain the lower bound. This paper provides some sufficient conditions for λ2,1,1(T) = Δ2(T). Furthermore, we show that the sufficient conditions we provide are also necessary for trees with diameter at most 6.
Źródło:
Discussiones Mathematicae Graph Theory; 2017, 37, 3; 611-622
2083-5892
Pojawia się w:
Discussiones Mathematicae Graph Theory
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hazard of Runaway of Nitration Processes in Nitrocompounds Production
Autorzy:
Kozak, G. D.
Raikova, V. M.
Powiązania:
https://bibliotekanauki.pl/articles/357950.pdf
Data publikacji:
2010
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
runaway
nitration
oxidation
detonation
failure diameter
sulfuric acid
Opis:
Hazard of runaway of nitration processes in nitrocompounds production was investigated. Temperature rise in DNT nitration mixes under near adiabatic conditions was measured, and derivative dT/dζ was computed. Heat evolution rate caused by nitration (primary reaction) and oxidation (secondary reaction) were examined by means of elaborated mathematical model. Limiting values of T and dT/dζ for safe process were determined. The second part of investigation concerns detonability of solutions of nitrocompound in sulfuric acid. The detonation failure diameter df and detonation velocity D of solutions of trinitrotoluene, dinitrotoluene, and trinitrobenzene in sulfuric acid and oleum have been measured in the wide range of concentrations at T = 90C. It was shown that the detonability of the nitrocompounds depends signifcantly on the sulfuric acid content. The minimum value of df for the mixture TNT/oleum is about 2 mm, i.e., 30 times less, than that for melted TNT, and practically equals to df of nitroglycerine.
Źródło:
Central European Journal of Energetic Materials; 2010, 7, 1; 21-32
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detonability of Ammonium Nitrate and Mixtures on Its Base
Autorzy:
Kuzmin, V.
Kozak, G.
Mikheev, D.
Powiązania:
https://bibliotekanauki.pl/articles/357972.pdf
Data publikacji:
2010
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
improvised explosive
ammonium nitrate
detonability
failure detonation diameter
Opis:
Quantities of improvised explosive devices on a base of industrial explosives that were applied at criminal incidents or were withdrawn from illegal circulation were reduced on average on 9% during last decade. This tendency is explained in particular by toughening of control under circulation of commercial explosive devices. The most commonly used improvised explosives according to returns of The Forensic Science Center of Ministry of Internal Affairs are mixtures on a base of ammonium nitrate with organic fuels and aluminum powder. Quantitative and qualitative compositions of such improvised mixtures can be various. The most essential question for a criminal case investigator is argument that excepted substance is explosive one. In this connection detonability of the mixtures on base fne (particle size was near 20 microns) and granulated ammonium nitrate with some organic fuels and aluminum powder was experimentally investigated. Failure detonation diameters of systems were measured experimentally.
Źródło:
Central European Journal of Energetic Materials; 2010, 7, 4; 335-343
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Universal equations for Pythagorean and Sauter-type formulas of mean value calculation and classification of the Extended Pythagorean Means
Autorzy:
Drzymała, J.
Powiązania:
https://bibliotekanauki.pl/articles/88936.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
average value
mean size
mean diameter
weighted mean
Opis:
A general equation, combining the Pythagorean and Sauter-type formulas, which can be used for calculation of a mean of a set of values is given and discussed in the paper. A classification of means, forming the Extended Pythagorean Means family, including power (arithmetic, geometric, quadratic, cubic, etc.), inverted power (harmonic, inverted quadratic, inverted cubic, etc.), and Sauter-type (volumesurface, volume-length, etc.) is presented. The calculated means, depending on their type, are different. Formulas for calculating mean values for a set of values treated individually, in groups and as a fraction (weighted mean) are also given.
Źródło:
Mining Science; 2017, 24; 227-235
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on vibration evolution of a ball bearing without the cage under local variable-diameter raceway damage
Autorzy:
Zhou, Enwen
Zhao, Yanling
Zhang, Huanqing
Powiązania:
https://bibliotekanauki.pl/articles/2200877.pdf
Data publikacji:
2023
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
ball bearing
vibration evolution
variable-diameter raceway
damage
Opis:
This article presents an analysis of vibration evolution of a ball bearing without the cage. A vibration model in which time-varying displacement, time-varying stiffness, contact force and collision force are comprehensively considered, is proposed. On this basis, the law of motion of the bearing is studied. It is shown that a variable-diameter raceway affects the radius of curvature, which effects the dispersion of rolling elements. The damaged variable -diameter raceway leads to discrete failure, contact force and collision force of rolling elements, which are main reasons that cause vibration mutation. The bearing motion changes from quasi-periodic to chaotic motion.
Źródło:
Journal of Theoretical and Applied Mechanics; 2023, 61, 1; 129--146
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 222

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