Assessment of airborne particulate matter (PM<inf>2.5</inf>) in university classrooms of varrying occupancy

Air pollution is a major concern in Pakistan. Levels of particulate matter (PM2.5) in educational built environments, have not yet been studied comprehensively in Pakistan. This study was conducted to assess relationships between indoor and outdoor particulate matter in classrooms of the University of the Punjab, Lahore, using a DUSTTRAK Aerosol Monitor (TSI Model 8520). Sampling for PM2.5 concentrations was carried out simultaneously outdoors and indoors in different classrooms on the campus. According to the level of occupancy three classrooms were selected i.e. Classroom I: low occupancy, Classroom II: medium occupancy and Classroom III: high occupancy. Simultaneous outdoor measurements were carried out at rooftop of each classroom. A tracer method was used to measure the air change per hour in each classroom. The 24 hour average concentrations of PM2.5 in Classrooms I, II and III were observed to be 282 μg/m3, 75 μg/m3 and 673 μg/m3 whereas 24 hour average outdoor levels were 324 μg/m3, 121 μg/m3 and 998μg/m3 respectively. Results showed a significant impact of ambient air and occupancy level on PM2.5 levels inside classrooms and all observed values exceeded the WHO limits

Comparative study of particulate matter in the transport microenvironment (buses) of Pakistan and UK

Transport microenvironments can contain higher levels of particulate matter due to infiltration from the roads, vehicular exhaust and commuter’s activities. The present study monitored PM, CO2, CO, temperature and relative humidity levels in diesel-powered buses in Pakistan and United Kingdom. Two routes of almost the same travelling distance were selected in Pakistan and the UK. Indoor air quality of the buses was monitored to determine the exposure faced by the commuters on inter-city journeys. While the observed levels in both countries were not in compliance with the WHO guidelines, levels of particulate matter were much higher in Pakistan than the concentrations in UK

Normal soaking extraction (NSE) of rotenone from Derris elliptica

Derris elliptica or the tuba plant contains rotenone, bio-active compound known that has the potential to be used as bio-pesticide. Bio-pesticide is the best-known alternative bio-pesticide which has the potential to replace the use of conventional pesticides, as it is more environmentally friendly. The main objective of the paper is to obtain the best extraction solvent for optimizing the yield in rotenone extraction. Rotenone was extracted from Derris root using three different parts of roots and three types of solvent in Normal Soaking Extraction (NSE). The types of Derris roots are: (1) Fine root (2) Coarse root (3) Stem. The three types of solvent system are: (1) Acetone 95 % (v/v), (2) Chloroform 99.9 % (v/v) and (3) a mixture of ethanol: H2O (9:1) added with oxalic acid (1mg/ml). The liquid crude extracts were further cleaned up to remove the fine debris of roots. The presence of rotenone was confirmed using qualitative analysis Thin Layer Chromatography (TLC) and thereupon the determination of rotenone content was carried out using High Performance Liquid Chromatography (HPLC). From the results obtained, it was found that the Normal Soaking Extraction (NSE) using acetone 95 % (v/v) was the best method to extract the highest yield of rotenone; 1.14 % (w/w)

CRF based feature extraction applied for supervised automatic text summarization

Feature extraction is the promising issue to be addressed in algebraic based Automatic Text Summarization (ATS) methods. The most vital role of any ATS is the identification of most important sentences from the given text. This is possible only when the correct features of the sentences are identified properly. Hence this paper proposes a Conditional Random Field (CRF) based ATS which can identify and extract the correct features which is the main issue that exists with the Non-negative Matrix Factorization (NMF) based ATS. This work proposes a trainable supervised method. Result clearly indicates that the newly proposed approach can identify and segment the sentences based on features more accurately than the existing method addressed

Pengaruh Laju Aliran Air terhadap Temperatur Sistem Mesin Pengkondisian Udara Hibrida Menggunakan Kondensor Dummy Tipe Helical Coil (Diameter Pipa 1/4") sebagai Water Heater dengan Pembebanan 2000 Watt

Energy saving is one way to reduce energy USAge without decreasing the results. This way can be obtained byusing the hybrid air conditioning. Other than energy saving, the hybrid air conditioning also can reduce theeffects of global warming by condenser waste heat recovery. This research aims to investigate the effect ofvariations flow rate in water heater tank to the system temperatures of hybrid air conditioning using helical coiltype of dummy condenser with 1/4˝ diameter of copper pipe. Experimental method is used in this research. Thetest was conducted with several water flow rate variations (1/3, 2/3, and 3/3 valve openings) and using coolingload of 2000 Watt as residential cooling load simulation. The result showed that the water temperature in waterheater tank was changed in every water flow rate variations. The highest water temperature was obtained at39.77˚C for 0 valve opening (full-closed valve), but, the lowest water temperature was obtained at 32.57˚C in3/3 valve opening (full-open valve)

The Phenomena of Spreading of Hydrotalcite Sol on A Porous Silica Surface Governed by Marangoni Effect

Wetting phenomena plays a crucial role in a wide range of technological applications. Spreading of liquids on solids involving phase change is encountered in many areas ranging from biological systems to industrial applications such as coatings, printing, painting and spraying. The fundamental study on wetting of membrane precursors namely hydrotalcite sols on a porous silica surface with different types of precursor material was successfully carried out. Relationship between the contact angle of a hydrotalcite droplet on silica surface and the Marangoni effect was also investigated. The presence of PVA in hydrotalcite sols was found to influence the rheological properties of the sols significantly, resulting in higher viscosity and ultimately leading to lower contact angle on solid surfaces. The degree of hydrotalcite's philicity on a substrate was improved by the addition of PVA solution. In this study, the spreading of a liquid droplet on a solid surface controlled by a surface tension gradient, due to Marangoni effect was found to drive better spreading of the liquid droplet. Marangoni Number, Ma was found to be proportionally related with the surface tension of the sols but inversely proportional to contact angles of the sols. Marangoni forces that decreased the contact angle, promoted spreading of hydrotalcite droplets on the selected glass substrates.Keywords: contact angle, hydrotalcite, marangoni effect, spreading, wetting evolutio

A slope-theory approach to electrical probe recording on phase-change media

Copyright © 2005 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Journal of Applied Physics 97 (2005) and may be found at http://link.aip.org/link/?JAPIAU/97/103537/1notes: The first paper to address theoretically the issue of writing resolution in electrical probe recording on phase-change media. The theory combined the thermal, kinetic, and electronic properties of the storage medium in an analytical framework to predict the ultimate writing resolutions of this technology. The theory also provided directions in material selection and design to increase the resolution and hence storage density of this new technology. The work led to invited presentations at on probe-based storage at the IEEE/IoP Magnetics Society Wohlfarth Lecture Meeting, London, April 2005 and at the Seagate Research Conclave, June 2007 at Sprintown, Northern Ireland.A theoretical approach to predicting the spatial extent of the amorphous to crystalline transition region during the probe recording process on phase-change storage media is presented. The extent of this transition region determines the ultimate achievable linear density for data storage using phase-change materials. The approach has parallels with the slope theory used to find magnetic transition lengths in magnetic recording, and shows that the amorphous to crystalline transition length can be minimized by reducing the thickness of the phase-change layer, by minimizing lateral heat flow, and by maximizing the ratio of the activation energy for crystallization to the transition temperature Ec/Tt

Seasonal variation of particulate matter in the ambient conditions of Khanspur, Pakistan

Concentrations of particulate matter tend to vary with shifting seasons. Levels of particulate matter were monitored during the summer and winter season in Khanspur, a high altitude tourist resort in Pakistan. A DustTrak DRX (Model 8533, TSI Inc.) and Kestrel 4500 Pocket Weather Tracker (Nielsen- Kellerman) were installed at selected site in Khanspur and run for 24 hours. During summer the 24- hour average concentrations of PM1, PM2.5, PM4, PM10 and PMTotal were 96 ± 26.42, 106± 29.02, 118± 33.3, 163± 52.5 and 209 ± 79.5 μg/m3 while these were considerably lower during the winter season for the same size fractions (62 ± 48.6, 63± 49.3, 63 ± 49.5, 65.33 ± 50.06 and 66.96 ± 50.78μg/m3). A one way ANOVA was applied on the obtained data and it was concluded that seasons have a substantial impact upon PM concentrations. Moreover, this study provides evidence that seasonal variation of particulate matter is influenced by meteorological parameters