scholarly journals Wettability and Phylogenetic Development of Feather Structure in Water Birds

1970 ◽  
Vol 52 (2) ◽  
pp. 469-479 ◽  
Author(s):  
A. M. RIJKE

1. The water repellency of feathers is determined mainly, but not exclusively, by a structural parameter which can be expressed in terms of diameter and spacing of the barbs and barbules. 2. Effective waterproofing properties result from the optimal balance of structural parameter and resistance to water penetration. 3. Comparison of the structural parameters for water birds with the geological time interval of their earliest fossil record shows a phylogenetic tendency toward optimizing waterprooftng properties with the course of time. 4. Several behavioural patterns are discussed which may have evolved under the selective pressure of the quality of water repellency and resistance to water penetration.

2014 ◽  
Vol 54 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Monika Kováčová ◽  
Miloš Matúš ◽  
Peter Križan ◽  
Juraj Beniak

The quality of a high-grade solid biofuel depends on many factors, which can be divided into three main groups - material, technological and structural. The main focus of this paper is on observing the influence of structural parameters in the biomass densification process. The main goal is to model various options for the geometry of the pressing chamber and the influence of these structural parameters on the quality of the briquettes. We will provide a mathematical description of the whole physical process of densifying a particular material and extruding it through a cylindrical chamber and through a conical chamber. We have used basic mathematical models to represent the pressure process based on the geometry of the chamber. In this paper we try to find the optimized parameters for the geometry of the chamber in order to achieve high briquette quality with minimal energy input. All these mathematical models allow us to optimize the energy input of the process, to control the final quality of the briquettes and to reduce wear to the chamber. The practical results show that reducing the diameter and the length of the chamber, and the angle of the cone, has a strong influence on the compaction process and, consequently, on the quality of the briquettes. The geometric shape of the chamber also has significant influence on its wear. We will try to offer a more precise explanation of the connections between structural parameters, geometrical shapes and the pressing process. The theory described here can help us to understand the whole process and influence every structural parameter in it.


10.14311/1554 ◽  
2012 ◽  
Vol 52 (3) ◽  
Author(s):  
Peter Križan ◽  
Miloš Matúš ◽  
Jaan Kers ◽  
Djordje Vukelić

In this paper, we will present the impact of the conical shape of a pressing chamber, an important structural parameter. Besides the known impact of the technological parameters of pressing chambers, it is also very important to pay attention to their structural parameters. In the introduction, we present a theoretical analysis of pressing chamber conicalness. An experiment aimed at detecting this impact was performed at our institute, and it showed that increasing the conicalness of a pressing chamber improves the quality of the final briquettes. The conicalness of the pressing chamber has a significanteffect on the final briquette quality and on the construction of briquetting machines. The experimental findings presented here show the importance of this parameter in the briquetting process.


2017 ◽  
Vol 3 (1) ◽  
pp. 112-126 ◽  
Author(s):  
Ilaria Cristofaro

From a phenomenological perspective, the reflective quality of water has a visually dramatic impact, especially when combined with the light of celestial phenomena. However, the possible presence of water as a means for reflecting the sky is often undervalued when interpreting archaeoastronomical sites. From artificial water spaces, such as ditches, huacas and wells to natural ones such as rivers, lakes and puddles, water spaces add a layer of interacting reflections to landscapes. In the cosmological understanding of skyscapes and waterscapes, a cross-cultural metaphorical association between water spaces and the underworld is often revealed. In this research, water-skyscapes are explored through the practice of auto-ethnography and reflexive phenomenology. The mirroring of the sky in water opens up themes such as the continuity, delimitation and manipulation of sky phenomena on land: water spaces act as a continuation of the sky on earth; depending on water spaces’ spatial extension, selected celestial phenomena can be periodically reflected within architectures, so as to make the heavenly dimension easily accessible and a possible object of manipulation. Water-skyscapes appear as specular worlds, where water spaces are assumed to be doorways to the inner reality of the unconscious. The fluid properties of water have the visual effect of dissipating borders, of merging shapes, and, therefore, of dissolving identities; in the inner landscape, this process may represent symbolic death experiences and rituals of initiation, where the annihilation of the individual allows the creative process of a new life cycle. These contextually generalisable results aim to inspire new perspectives on sky-and-water related case studies and give value to the practice of reflexive phenomenology as crucial method of research.


2018 ◽  
Vol 28 (4) ◽  
pp. 484-497
Author(s):  
Phan Thị Kim Văn ◽  
Bùi Trần Vượng

The quality of water in Bac Binh according to chemical and microbiological analyses


Author(s):  
Santhosh K. M ◽  
S. Prashanth

Urban development, agricultural runoff and industrialization have contributed pollution loading on the environment.  In this study Hemavathi river water from a stretch from its origin point to its sangama was studied for pollution load by determining parameters of water quality like pH, Alkalinity,  Ca, Mg, Nitrate, TDS, BOD, COD , and the results were compared with WHO and BIS standards to draw final conclusion on the quality of water.


Author(s):  
Aliva Bera ◽  
D.P. Satapathy

In this paper, the linear regression model using ANN and the linear regression model using MS Excel were developed to estimate the physico-chemical concentrations in groundwater using pH, EC, TDS, TH, HCO3 as input parameters and Ca, Mg and K as output parameters. A comparison was made which indicated that ANN model had the better ability to estimate the physic-chemical concentrations in groundwater. An analytical survey along with simulation based tests for finding the climatic change and its effect on agriculture and water bodies in Angul-Talcher area is done. The various seasonal parameters such as pH, BOD, COD, TDS,TSS along with heavy elements like Pb, Cd, Zn, Cu, Fe, Mn concentration in water resources has been analyzed. For past 30 years rainfall data has been analyzed and water quality index values has been studied to find normal and abnormal quality of water resources and matlab based simulation has been done for performance analysis. All results has been analyzed and it is found that the condition is stable. 


2018 ◽  
Vol 6 (1) ◽  
Author(s):  
Badusha M. ◽  
Santhosh S

The hydro geochemical features of Neyyar River for a period of one year from May 2015 to April 2016 were analyzed. Six sampling sites were fixed considering physiography and present landuse pattern of the river basin. The residents in the drainage basin are primarily responsible for framing a better landuse and thereby maintain a good water and sediment regime. Geospatial pattern of the present landuse of the study area indicated that the sustainability of this river ecosystem is in danger due to unscientific landuse practices, which is reflected in the river quality as well. The parameters such as hydrogen ion concentration, electrical conductivity, chloride, Biological Oxygen Demand, total hardness and sulphate of river water and Organic Carbon of river bed sediments were analyzed in this study. The overall analysis shows that the highland areas are characterized by better quality of water together with low organic carbon, which is mainly due to better landuse and minimal reclamation. The midland and lowland areas are characterized by poor quality of water with high organic carbon, which is due to high anthropogenic activities and maximum pollutants associated with the region together with the alteration in landuse from a traditional eco-friendly pattern to a severely polluted current pattern.


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