Biosorption of hazardous textile dyes from aqueous solutions by hen feathers: Batch and column studies

The biosorption potential of hen feathers (HFs) to remove hazardous textile dyes, namely congo red (CR) and crystal violet (CV), from their aqueous solutions was investigated in batch and dynamic flow modes of operation. The effect of biosorption process parameters such as solution pH, initial dye concentration, temperature, feed flow rate and bed height was studied. Biosorption equilibrium data were well described by the Langmuir isotherm model. Kinetic studies at different temperatures showed that the rate of biosorption followed the pseudo second-order kinetics well. A thermodynamic study showed that biosorption of both CR and CV was spontaneous and endothermic. Breakthrough time increased with increase in bed height but decreased with increase in flow rate. The Thomas model showed good agreement with the dynamic flow experimental data. Overall, the results suggest the applicability of HFs as an efficient biosorbent for removal of carcinogenic textile dyes from aqueous media.     

Removal of Pb(II) from aqueous solutions by adsorption onto clayey soil of Indian origin: Equilibrium, kinetic and thermodynamic profile

The feasibility of applying natural, untreated clayey soil as low-cost alternative adsorbent for Pb(II) removal from aqueous solutions was investigated with a batch experimental set-up. Experiments were carried out as a function of initial solution pH (1?C8), contact time (10?C360 min), initial Pb(II) concentration (20?C100 mg L^?1), adsorbent dose (0.5?C5 g) and temperature (303?C333 K). Adsorption equilibrium data were well described by the Langmuir isotherm with maximum adsorption capacity of 121.86 mg g^?1 at 303 K. Adsorption of Pb(II) followed pseudo-second-order kinetics. Gibbs free energy (??G⁰) was spontaneous for all interactions, and the adsorption process exhibited exothermic enthalpy values. The adsorbent was easily regenerated by using 0.1M HNO₃ solution and was reused for five sorptiondesorption cycles without any considerable loss in adsorption capacity. It could be concluded that clayey soil may be used as an inexpensive and effective adsorbent without any treatment or any other modification for the removal of Pb(II) ions from aqueous solutions.     

Concept of an offline correction method based on historical data for milling operations using industrial robots

Industrial robots for machining applications have been researched to achieve an alternative, flexible and less expensive machining technology against conventional machine tools. The previous work on industrial robots indicates that industrial robots are only applicable without requirement of high accuracy. The low accuracy and instability under various configurations of industry robot are still major barriers for deploying robots for machining in industries. In this paper, a new method, namely historical data based correction (HDC), is presented to improve the accuracy of industrial robots for milling operations. First, the HDC method is able to calculate the corrected values to compensate the systematical errors during milling operations. Consequently, new tool paths of robots with corrected values are generated. In addition, the HDC method is able to fulfill the requirement of large-scale production. With the proposed method, the surface quality of the machined parts can be improved by more than 60 % without using any additional measuring systems.     

Shortcut Design Approach for Spiral Heat Exchangers

This paper presents a shortcut method for the sizing of spiral plate heat exchangers. The approach consists of an iterative process where physical dimensions like plate width and external spiral diameter are given initial values; convergence is achieved until the calculated pressure drop and heat duty meet the required specifications of the design problem. The results of the application of the approach are compared with case studies reported in the literature. A numerical study using computational fluid dynamics is performed to rate the performance of the geometry. The temperature profiles of the exchanger calculated analytically show the same tendency as those obtained numerically; thus, the method provides a good starting point for estimating the dimensions of spiral heat exchangers in single-phase applications.     

Database intrusion detection using sequence alignment

Information is considered to be the most valuable asset of any organization and hence, it should be securely maintained. However, rapid proliferation of the Internet and Web applications has increased the threat of information security breaches. Traditional database security mechanisms are often not sufficient to protect sensitive information against novel attacks. Intrusion detection systems (IDS) are used to detect any such intrusion, once traditional security mechanisms have been compromised. User-level profile is effective for database intrusion detection, but maintaining such profiles is not practical for an organization with a large number of users. Thus, an IDS needs to be flexible enough to choose a profile granularity according to the type of the organization. Further, only intra-transactional pattern matching for intrusion detection is not quite effective for detecting intrusion in a database. We propose an IDS that uses inter-transactional as well as intra-transactional features for intrusion detection. It supports selection of profile and transactional feature granularity as well. We use sequence alignment as a tool for comparing database access patterns of genuine users and intruders.     

Matrices over semirings

Introducing the concept of semi-invertibility of square matrices over semirings, some sufficient conditions for semi-invertibility of square matrices over various kinds of semirings are obtained. Also a necessary and sufficient condition for semi-invertibility of square matrices over semirings is obtained.     

Broadband scalable model for Si‐RF on‐chip spiral inductors with substrate eddy current effect

A new broadband scalable compact model for on‐chip spiral inductor is presented. It includes a substrate network and a high resistive component to accurately capture the substrate eddy current effect, skin and proximity effects at high frequencies. The proposed model shows a good match with the measurement results over a frequency range of up to 20 GHz. An automated parameter extraction and optimization procedure has been developed using equivalent circuit analysis and particle swarm optimization. We achieved good scalability for all model parameters with respect to spiral layout geometry. © 2007 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.     

Alternative Design Approach for Plate and Frame Heat Exchangers Using Parameter Plots

The simultaneous design and specification of heat exchangers of the plate-and-frame type is analyzed. A pictorial representation of the design space is used to guide the designer toward the selection of the geometry that best meets the heat duty within the limitations of pressure drop. The design space is represented by a bar plot where the number of thermal plates is plotted for three conditions: (1) for fully meeting the required heat load, (2) for fully absorbing the allowable pressure drop in the cold stream, and (3) for fully absorbing the allowable pressure drop in the hot stream. This type of plot is suitable for representing the design space, given the discrete nature of the plate geometrical characteristics, such as effective plate length and plate width. Applications of the use of bypasses as a design strategy are also presented.     

Toward automating Hammersmith pulled-to-sit examination of infants using feature point based video object tracking

Hammersmith Infant Neurological Examination (HINE) is a set of tests used for grading neurological development of infants on a scale of 0 to 3. These tests help in assessing neurophysiological development of babies, especially preterm infants who are born before (the fetus reaches) the gestational age of 36 weeks. Such tests are often conducted in the follow-up clinics of hospitals for grading infants with suspected disabilities. Assessment based on HINE depends on the expertise of the physicians involved in conducting the examinations. It has been noted that some of these tests, especially pulled-to-sit and lateral tilting, are difficult to assess solely based on visual observation. For example, during the pulled-to-sit examination, the examiner needs to observe the relative movement of the head with respect to torso while pulling the infant by holding wrists. The examiner may find it difficult to follow the head movement from the coronal view. Video object tracking based automatic or semi-automatic analysis can be helpful in this case. In this paper, we present a video based method to automate the analysis of pulled-to-sit examination. In this context, a dynamic programming and node pruning based efficient video object tracking algorithm has been proposed. Pulled-to-sit event detection is handled by the proposed tracking algorithm that uses a 2-D geometric model of the scene. The algorithm has been tested with normal as well as marker based videos of the examination recorded at the neuro-development clinic of the SSKM Hospital, Kolkata, India. It is found that the proposed algorithm is capable of estimating the pulled-to-sit score with sensitivity (80%-92%) and specificity (89%-96%).