Experimental and parametric investigation of effects of built-in staircases on the dynamics of RC buildings

Past earthquakes, in many instances, have demonstrated poor performance of commonly used built-in staircase configurations. Codal provisions in India pertaining to staircases present a rather simple approach wherein the effects of built-in staircases on the overall dynamic properties or on the local behavior of structures are not addressed explicitly. Studies in the past have highlighted the scale of such effects, but most of them have relied completely on analytical models of buildings. This study analyzes the adequacy of the codal provisions by investigating two finite element (FE) models calibrated using ambient and forced vibration measurements. The effects of variations in building height, layout of staircase in plan, and presence of masonry infill walls in stairwells are also examined. The codal guidelines regarding empirical estimation of period and provision of enclosure walls around built-in staircases are found to be adequate. However, for the case of built-in staircases without enclosure walls, the force and displacement demands on landing beams are found to be considerably high. Drift-based approaches to estimate these demands are proposed.     

Dynamics of communal land degradation and its implications in the arid mountains of pakistan: A study of District Karak,Khyber Pakhtunkuwa

Similar to other areas of Pakistan, land resources in Khyber Pakhtunkhwa （KP） is kept under various ownership regimes for socio-economic and ecological benefits. For the last three to four decades, communal lands and resources are subjected to high rate of degradation and deterioration, which is leading to multifarious socio-economical and ecological implications. This paper intends to look into factors that are responsible for the degradation of communal land and the adaptability of the management mechanisms developed by the local inhabitants to conserve these resources. Moreover, this study also explores the sustainability of these adopted strategies in present circumstances. Data regarding socio-economic parameters of the inhabitants and their interactions with communal lands were collected through questionnaire cum interview method. As long-term climatic data for the area do not exist therefore focus group discussions were conducted to document the changing trend in rainfall regimes and temperature variations for the last about four decades. Results indicate that communal lands are highly vulnerable to degradation due to biophysical and anthropogenic factors. Local inhabitants have developed suitable measures to control the situation, however, accelerated socio-economic transformations in the area have weakened the role of local institutions and that led to further degradation of these resources. Nevertheless, a number of locally formulated rules have been revived and implemented and it is hoped that these threatened resources would be conserved.     

Petrogenesis of the Late Cretaceous Tholeiitic Volcanism and Oceanic Island Arc Affinity of the Chagai Arc, Western Pakistan

The Late Cretaceous Chagai arc outcrops in western Pakistan, southern Afghanistan and eastern Iran. It is in the Tethyan convergence zone, formed by northward subduction of the Arabian oceanic plate beneath the Afghan block. The oldest unit of the Chagai arc is the Late Cretaceous Sinjrani Volcanic Group. This is composed of porphyritic lava flows and volcaniclastic rocks, and subordinate shale, sandstone, limestone and chert. The flows are fractionated low-K tholeiitic basalts, basaltic-andesites, and andesites. Relative enrichment in their LILE and depletion in HFSE, and negative Nb and Ta and positive K, Ba and Sr anomalies point to a subduction-related origin. Compared to MORB, the least fractionated Chagai basalts have low Na2O, Fe2O3T, CaO, Ti, Zr, Y and 87Sr/86Sr. Rather than an Andean setting, these results suggest derivation from a highly depleted mantle in an intraoceanic arc formed by Late Cretaceous convergence in the Ceno-Tethys. The segmented subduction zone formed between Gondwana and a collage of small continental blocks (Iran, Afghan, Karakoram, Lhasa and Burma) was accompanied by a chain of oceanic island arcs and suprasubduction ophiolites including Semail, Zagros, Chagai-Raskoh, Kandahar, Muslim Bagh, Waziristan and Kohistan-Ladakh, Nidar, Nagaland and Manipur. These complexes accreted to the southern margin of Eurasia in the Late Cretaceous.     

AN EVALUATION OF DISPERSION COEFFICIENTS FOR USE IN AIR QUALITY MODELS

Standard deviations of concentration in horizontal andvertical directions i.e. y andz have been estimated by using fivedifferent schemes based on empirical(due to Pasquill and Briggs)schemes and sophisticated methods(due to Irwin, Draxler, Taylor, Hanna et al.). The fiveschemes are discussed atlength. The purpose of this study is to make use ofmeteorological observations whichare routinely available, to test all the above methods andintercompare the resultswith one another and observations so that the sensitivityof each schemeunder various atmospheric stability conditions could beassessed. It has beenfound that the existing schemes are good enough to providereasonable estimates ofdispersion coefficient (y) during highly unstableconditions (Pasquill stability classes A and B). However, thesame is not true for the case when the stability increasesfrom C to F and turbulencedecreases, specifically during stable atmospheric conditions,when the observedvalues were found to be much higher than all the existingschemes. This suggests thatwhile we continue to use the current methods of estimatingthe dispersion parameters,a rigorous search is required for methods which give predictionswhich are close-to-realityduring such conditions which are represented by lowlevels (in terms of magnitude)of atmospheric turbulence leading to higher levelsof pollution.As one of the sophisticated methods requiresthe use of v and w (standard deviationsof wind velocity fluctuation in y and z directions),these have been estimated andvalidated with observed data (field experiments conductedby EPRI at Kincaid).Statistical evaluation of v and wbased on performance measures indicate a goodperformance of the parameterisations adopted in thisstudy. In the case of w duringunstable conditions a comparison of three differentschemes with observations is made.     

GIS-based spatial landslide distribution analysis of district Neelum,AJ&K,Pakistan

Natural Hazards - The Landslide happens in mountainous regions due to the catastrophe of slope through intensive rain and seismicity. The Himalayas is one of the susceptible parts of the world in...     

Morphotaxonomy and seasonal distribution of planktonic and benthic Prorocentrales in Karachi waters, Pakistan Northern Arabian Sea

Morphotaxonomy and seasonal abundance of dinoflagellates of the genera Prorocentrum and Mesoporos(Prorocentrales) were studied from nutrient-rich waters,Karachi Harbor and the mouth of the Manora Channel,Pakistan during May 2002-July 2003.Using both light and scanning electron microscopy,13 species of Prorocentrales were identified according to cell shape,size,ornamentation of thecal plates,and architecture of apical platelets,apical pore area,marginal pores,and intercalary bands.P.sigmoides,P.arcuatum,P.scutellum,P.donghaiense,P.balticum,P.minimum,P.emarginatum,P.lima,P.faustiae,and Mesoporos perforatus constitute new records for sindh coast of Pakistan.The most abundant species were P.minimum/P.balticum(4.5×103 cells/L),P.micans(1.1×103 cells/L),P.gracile/P.sigmoides(2.5×102 cells/L) and P.donghaiense(6.6×103 cells/L) at temperatures of 29-31℃ and salinities of 35-40.Maximum abundance was observed in winter and lower abundance in summer.There was no significant change in the distribution of species between stations except for the benthic species which occurred close to Karachi Harbor waters.Significant positive correlations were observed between Prorocentrum spp.and temperature(R 2 =0.27) and negative correlations with salinity(R 2 =-0.32) except for P.minimum and P.emarginatum which has negative correlation with temperature(R 2 =-0.24) and positive with salinity(R 2 =0.08,0.19).The finding of potential okadaic-acid producing species of benthic Prorocentrum call for monitoring for possible human health problems in this region.     

Late Neogene sequence stratigraphic evolution of the Foz do Amazonas Basin,Brazil

The margin of the Foz do Amazonas Basin saw a shift from predominantly carbonate to siliciclastic sedimentation in the early late Miocene. By this time, the Amazon shelf had also been incised by a canyon that allowed direct influx of sediment to the basin floor, thus confirming that the palaeo‐Amazon fan had already initiated by that time (9.5–8.3 Ma). Above this interval, during a prolonged lowstand, Messinian third‐order sequences are preserved only in the incised‐valley fills of the canyon with no equivalent strata on the shelf. Third‐ and fourth‐order sequences younger than Messinian are preserved on the shelf after sea‐level rise above the shelf by the early Pliocene. Sequences younger than 3.8 Ma often show fourth‐order cyclicity with an average duration of 400 ka (larger scale eccentricity cycles) often preserved in high‐sedimentation‐rate areas of river deltas. Mass wasting and transportation of slope sediments to the basin began to play an important role in sediment dispersal at least as far back as the mid‐Pliocene, after rapid progradation had produced steeper slopes more prone to failure.     

Biodegradation of Cypermethrin by a newly isolated actinomycetes HU-S-01 from wastewater sludge

A new cypermethrin degrading strain was isolated from wastewater sludge using enrichment technique. On the basis of morphological, physiological, biochemical characteristics tests and 16S rDNA sequence analysis, the strain was determined to be a Streptomyces species, probably a strain of Streptomyces parvulus, so it was designated as Streptomyces sp. HU-S-01. The strain Streptomyces sp. HU-S-01 is aerobic and optimum growth temperature for the strain was found to be 26–28 °C with initial pH range 6.0-9.0 and pH 7.5 was found to be the optimum. This strain can also completely degrade 3-phenoxybenzoic acid within 96 h at the concentration of 50 mg/L. The kinetic constants Vmax, Km, Kcat and Kcat/ Km of enzyme for cypermethrin were 1.236 ?mol/min, 6.418 ?mol/mL, 13.493 min and 2.102 mL/mol.min, respectively. The degradation products of cypermethrin were identified using gas chromatographmass spectrometric (GC-MS) analysis. The degradation pathway followed by HU-S-01 involves oxidative as well as hydrolyzing. Biodegradation ability of strain Streptomyces sp. HU-S-01 without toxic byproducts reveals its potential for further study as a biological agent for the remediation of soil, water or crops, contaminated with cypermethrin.     

Shear-free and cavity models with plane symmetry

This paper aims to explore anisotropic planar analytical models for dissipative as well as non-dissipative matter distributions. We relate the Weyl tensor and physical variables of matter distribution. Darmois junction conditions are formulated on internal and external hypersurfaces. It is found that our dissipative models show the presence of cavity with non-zero expansion. Finally, we investigate two types of solutions with zero shear as well as heat flux by a specific choice of the mass function and by restricting pressure.