Water scarcity is becoming a major problem in High Mountain Basins of Indian Himalaya. Access to fresh water becomes a core concern for every dweller in the summer season all across the Indian ...Himalayan Region. This paper presents an assessment of two low yielding perennial springs in one of the urban center located in the very steep mountain slopes of Lesser Himalaya. Spring hydrographs were analyzed to investigate the variability and availability of spring flow in three seasons. Dynamic spring flow volume in storage and time at which the flow may cease were also assessed, as they play a crucial role for planning short-term measures. The linear model using the exponential decay equation is found to be sufficiently accurate to model the recession characteristics of spring outflow from the hardrock aquifers for winter season, as the main contribution comes from baseflow with delayed interflow, which is slow diffuse flow in nature. The present study examines the findings from 1 year of spring outflow and rainfall when deficient monsoonal rainfall (moderate drought) is recorded in major parts of the country. The data can play a significant role in estimating dependable minimum water availability from the spring outflow and planning for appropriate capacity of low to medium storage structure for conserving the excess water which goes unutilized even during the high scarcity period. The analysis of duration curve suggests, more focus should be given for conserving the surplus water available during the monsoon through appropriate storage structures, which can be used during the leanest month.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
When a material coating is left to dry on a substrate, cracking and peeling may set in which leads to the ultimate degeneration of the coating. Parameters like the elastic properties of the ...constituents of the coating, desiccation rate, role of substrate and the volume fraction of the constituent components of the coating affect the failure mechanism. We simulate desiccation of a 2-D vertical section of a layer of a two component (A,B) composite on a substrate to study the dependence of cracking and peeling on these parameters. For a given composite and substrate, it is observed that cracking or peeling depends only on the percentage of the constituents present in the composite. In our simulation,
p
is the volume fraction of the constituent having greater cohesion (B). The characteristic time of complete failure
t
crack
is found to increase linearly with decrease in desiccation rate. This rate of increase in
t
crack
is the highest for peeling and least for horizontal cracking. When adhesion between substrate and layer is stronger than the cohesion (BB) and adhesion (AB) of the constituents of the composite, peeling is least favoured. Failure by horizontal cracking gives way to vertical cracking as the percentage of the stronger component (B) increases. If adhesion between substrate and layer is weaker than that between the constituent components of the composite, peeling is dominant. Mechanical strength is found to be always greater for a composite than a pure material. If one component has low cohesive strength (AA), the strength of the composite can be greatly increased if the other component (B) is chosen such that adhesion (AB) becomes comparable to cohesion (BB). For certain combinations of the components, the composite is found to completely resist failure.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Several studies, both theoretical and experimental, show that sedimentary rocks have fractal pore–grain interface. The real rocks are 3-d structures with highly tortuous and often fractal pore ...spaces. Before attempting simulation of this daunting geometry, we present here, as a preliminary study, a simpler 2-d version. In this paper, a computer simulated 2-d sedimentary rock structure is generated by the relaxed bidisperse ballistic deposition model. Grains of two different sizes are dropped ballistically on a linear substrate. By changing the fraction of the two types of particles, the porosity of the rock structure can be tuned. The structure undergoes compaction through the relaxation of possible unstable overhangs. The micro structure of the pore space is investigated. The pore mass and the rock–pore interface show a fractal behaviour with the same fractal dimension indicating that the pore volume is a fractal. Our simulation results indicate that the process of compaction of grains during the deposition process seems to erase the dependency of the fractal dimension on the grain size distribution. The two point density correlation is measured for the pore space. It shows anisotropy which is an outcome of the growth rule. X-ray tomography of two-dimensional sections of real sedimentary rocks obtained from Mallorca Island is subjected to the same study and the results compared with those obtained from simulation. The simulation results agree qualitatively with the real rock sample. We also study diffusion on the pore space. Diffusion is found to be anomalous as is expected in fractal spaces. It also bears the signature of anisotropy of the structure. Diffusion studies on the real rock sample could not yield conclusive results as the system size is not large enough.
► 2-d simulation of sedimentary rock with desired porosity. ► Behaves as a volume fractal with interface dimension equal to void mass dimension. ► 2-point density correlation of pores shows realistic nature. ► Diffusion through pores is anomalous showing fractal signature. ► Comparative study with real rock sections shows similar behaviour.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
A map is proposed from the space of planar surface fracture networks to a four-parameter mathematical space, summarizing the average topological connectivity and geometrical properties of a network ...idealized as a convex polygonal mesh. The four parameters are identified as the average number of nodes and edges, the angular defect with respect to regular polygons, and the isoperimetric ratio. The map serves as a low-dimensional signature of the fracture network and is visually presented as a pair of three-dimensional graphs. A systematic study is made of a wide collection of real crack networks for various materials, collected from different sources. To identify the characteristics of the real materials, several well-known mathematical models of convex polygonal networks are presented and worked out. These geometric models may correspond to different physical fracturing processes. The proposed map is shown to be discriminative, and the points corresponding to materials of similar properties are found to form closely spaced groups in the parameter space. Results for the real and simulated systems are compared in an attempt to identify crack networks of unknown materials.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Interactions of Poly -Ethylene Oxide PEO of molecular weight 10
5
and gamma irradiation with variable doses (1–30 kGy) are studied for the thermal, crystalline and structural properties using ...differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) technique. Two states of PEO, viz. powder (P-S-series) and methanol solution (P-L-series) are subjected to irradiation and then cast into uniform films at room temperature. DSC results have revealed steady increment of crystallinity up to 20 kGy for P-S-series which starts reducing till 30 kGy. Conversely, P-L-series shows much enhanced crystallinity retained within low irradiation regime of 7 kGy, followed by sharp declining trend till 30 kGy. DSC is employed to study the influence of gamma radiation on multiple kinetic processes in an isoconversional melting of PEO using Friedman differential analysis. This study illustrates the variation of activation with degree of conversion of melting for different doses on irradiated PEO powder and methanol solution. Gamma irradiation is found to generate newer functional groups which are also established from FTIR study. Presence of –C=O and –C=C– groups in FTIR spectra reveals the predominance of scission during air assisted irradiation. FTIR spectra also prove higher degree of cross-linking in irradiation of methanol solution. The observations of DSC and FTIR are correlated with polymer microstructures. Therefore, selective irradiation dose can effectively be utilized to tailor the properties of PEO depending upon the exposed powder or methanol solution of polymer.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
.
The lifting Hele-Shaw cell (LHSC) is used to study adhesion as well as viscous fingering. In the present paper we report a series of observations of development of the interface for different ...viscous fluids, both Newtonian and non-Newtonian, in a LHSC operated at a constant lifting force. Glass and perspex are used as the plates in two different sets of experiments. The objectives are 1) to measure the time required to separate the plates as a function of the lifting force and 2) to note the force above which viscous fingering appears. We find that for the Newtonian fluids, the plate separation time follows a universal power law with the lifting force, irrespective of fluid and substrate. The non-Newtonian fluids too, with proper scaling obey the same power law. The appearance of fingering, however, depends on the properties of the fluid as well as the substrate. We suggest a modified form of the capillary number which controls the onset of fingering; this new quantity, termed the “fingering parameter” involves the dielectric constants of the substrate and fluid in addition to the viscosity and surface tension.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Instability at the interface separating different fluids, may develop under different conditions, leading to increased roughness of the boundary. A difference in viscosity of the fluids is usually ...responsible for viscous fingering, this occurs when the pressure on the low viscosity side is higher. We report here a reverse effect when a non-Newtonian fluid is squeezed between two plane surfaces by applying a force. We observe that a wave-like irregularity develops on the interface, though the viscosity of the air surrounding the fluid is negligible compared to the apparent viscosity of the thick potato starch gel under study. Development of the wavelength of the undulations as a function of the fluid composition and other factors is studied. We suggest a qualitative explanation for this effect, which is observed only in non-Newtonian fluids.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Bacterial biofilms pose the greatest challenge to implant surgeries leading to device-related infections and implant failure. Our present study aims at monitoring the variation in the biofilm ...architecture of a clinically isolated strain and ATCC 27853 strain of
Pseudomonas aeruginosa
on two polymeric biomaterials, used in implants. The perspective of our study is to recognize the potential of these two biomaterials to create biofilm infections and develop the understanding regarding their limitations of use and handle patients with this deeper insight. The final goal, however, is an accurate interpretation of substrate-microbe interactions in the two biomaterials, which will provide us the knowledge of possible surface modifications to develop of an efficacious anti-biofilm therapy for deterring implant infections. The reference strain ATCC 27853 and a clinical isolate of
P. aeruginosa
collected from urinary catheters of patients suffering from urinary tract infections, have been used as microbes while clinical grades of polypropylene and high density polyethylene, have been used as ‘substrates’ for biofilm growth. The variation in the nature of the ‘substrate’ and ‘conditioning layer’ of BSA have been found to affect the biofilm architecture as well as the physiology of the biofilm-forming bacteria, accompanied by an alteration in the nature and volume of EPS (extracellular polysaccharide) matrices.
Graphical Abstract
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Gamma irradiation changes the polymer microstructure and improves the ionic conductivity of Solid Polymer Electrolytes (SPE). The present paper introduces a deterministic fractal model of polymer ...molecules to study the effect of gamma irradiation on it. The effect of irradiation is implemented by repeated scission of molecules resulting in variation in polymer morphology. The ionic conductivity is assumed to be proportional to the effective velocity of ions. The velocity is calculated considering the trapping effect due to the random movement of ions through the large fractal polymer molecules and the segmental motion of the branches. Calculated conductivity is compared with the experimental curves which show a qualitative agreement.
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