Flat slab system being adopted in many buildings possesses many advantages in terms of architectural flexibility, use of space, easier framework and shorter construction time. However, the structural efficiency of the flat slab construction is hindered by its poor performance under earthquake loading. This undesirable behavior has originated from the insufficient lateral resistance due to the absence of deep beams or shear walls in the flat slab system. This gives rise to excessive deformations that cause damage in non-structural members even when subjected to earthquakes of moderate intensity. In the paper titled, “Seismic Evaluation of Flat Slab Buildings with Shear Wall”, the authors Prithwi Raj K, Umesh K Sharma, Yogendra Singh, Pradeep Bhargava and N M Bhandari report the behavior of flat slab-column system which was designed safe for resisting gravity loading and studied for lateral loading of Zones IV and V as defined in IS:1893-2002 for 8, 12 and 16 storey flat plate buildings. The effect of the introduction of shear wall on the improved behavior of flat slab-column system is studied using static nonlinear analysis, i.e., pushover analysis using SAP-2000 v11 software.

The second paper, “Simulation Study of the Performance of IEEE 802.11b WLAN Using OPNET Simulator”, by Onubogu O J, Azubogu A C O, Idigo V E, Okezie C C and Akpado K A presents a simulation study of the performance of IEEE 802.11b WLAN using OPNET IT Guru Academic Edition 9.1. The simulation results showed the impact of tuning the IEEE 802.11 protocol parameters like data rates, RTS/CTS threshold, fragmentation threshold and buffer size on the performance metrics such as throughput, delay and dropped data.

Circuit simulation is widely regarded as a critical step in the design flow. IBIS (I/O Buffer Information Specification) behavioral models have become the international standard to express input/output behavioral characteristics of ICs providing current versus voltage (DC IV), rising and falling Voltage versus Time (V/T) and packaging information of I/O pin in type of table information. IBIS model has become widely used among EDA vendors, semiconductor vendors and system designers. But widely used SPICE-based EDA tools do not support IBIS model in electronic analysis on chips. Therefore, the conversion of IBIS model into equivalent SPICE model becomes significant to many applications. The conversion of IBIS into SPICE algorithm can make circuit analysis faster and more efficient. The third paper, “Development of Analog SPICE Behavioral Model of PCI Buffer Based on IBIS Model”, by Nandakishore Yadav, Kulwant Singh and Ashutosh Gupta discusses a method to extract dynamic information from IBIS switching waveform V/T tables. The proposed method extracts gate voltages and model parameters of pullup/pulldown transistors from IBIS V/T tables and I/V tables. A comparison of simulation results between the proposed analog SPICE behavioral model and transistor level model (SPICE netlist) and the influence of waveform table load condition on the validity of the analog SPICE behavioral model is also included.

Digitally stored multimedia material is currently a rapidly growing resource due to the ongoing technological advancement in data storage, communication and computing. Digitally stored multimedia material is currently a rapidly growing resource due to the ongoing technological advancement in data storage, communication and computing. Transfer of long audio and video files via the Internet and the storage capacities of portable multimedia devices and personal computers have been rapidly increasing. The amount of available digital multimedia information is beginning to overwhelm the capacity of humans to manage and organize it. Thus, computerized solutions for automatic organization of the multimedia material are an attractive approach to access the content efficiently. Information indexing and retrieval is therefore an important field of application for automatic audio-video recognition. The fourth paper, “Audio-Video Based Classification Using SVM”, by K Subashini, S Palanivel and V Ramalingam proposes an effective technique to automatically classify audio-video clips into one of the six classes: music, news, sports, advertisement, cartoon and movie with an accuracy of 87%. Mel frequency cepstral coefficients are used as features to characterize audio content while color histogram coefficients are used as features to characterize the video content.

A nonlinear support vector machine learning algorithm is applied to obtain the optimal class boundary between the various classes.

Fossil energy, particularly derived from coal, does not find favor in the eyes of environmentalists who see coal as inherently dirty. The inorganic minerals present in the mined coal are desired up to certain levels due to their catalytic effects in gasification and liquefaction. The mineral contents in the mined coal are normally more than this desired level and reduce the energy efficiency of the fuel, besides contributing to the pollution. Demineralization prior to utilization to reduce the ash forming inorganic elements is an effective way to ensure environment-friendly combustion of coal. Concerted efforts are on to use less time-consuming and cost-effective techniques for removal of ash forming minerals from coal. Leaching with organic and inorganic leachants is one of the popular techniques. In the paper titled, “Diffuse Reflectance Spectra of Coals in the UV-Visible and Near-IR Regions”, the authors Manoj B and Kunjomana A G have used diffuse reflectance spectrometry in the UV-Visible and near-IR regions to study and interpret the effect of leachants and time of leaching for various ranks of coal.

An estimate says that each ton of recycled paper can save 17 trees, 380 gallons of oil, three cubic yards of landfill space, 4000 kW of energy and 7,000 gallons of water. This represents 64% energy savings, 58% water savings and 60 pounds less of air pollution. But the process of recycling involves a number of stages like reducing wet strength, repulping, screening, cleaning, de-inking, refining, bleaching and color stripping; each of these steps involves chemical treatments. It becomes necessary to adopt safe, eco-friendly and less expensive recycling techniques. The last paper, “Repulping of Waste Paper Containing High Wet Strength”, by Harsha S Chatrath and Rohit Durge presents an optimum combination of chemical treatments for easy and quick repulping of waste paper with high wet strength like tea bag filters. The authors concluded that of the various chemical treatments attempted, polyethylene glycol and sodium hydroxide combination were the best set of chemicals for waste paper repulping. Polyethylene glycol helps in the destruction of wet strength of paper and in destroying resinous material from paper. The treatment of polyethylene glycol in combination with sodium hydroxide gave best result, as it required less time for repulping of waste paper.

-- Elizabeth Zacharias
Consulting Editor