Studies on the influence of molecular weight and isotacticity of polypropylene on the formation of mesomorphic phase

Polypropylene (PP) blends with various molecular weight and isotacticity were prepared through solution blending and subjected to rapid melt quenching. Structural changes in the PP matrix during mesomorphic phase formation were measured by FTIR spectroscopy and wide‐angle X‐ray diffraction measurements. The blends with different molecular weight and isotacticity provided the pathway to understand their influence on mesomorphic phase formation. It is observed that low molecular weight PP with low isotacticity forms mesomorphic phase, whereas high molecular weight and low isotactic PP does not lead to the formation of mesomorphic phase. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Fermentative hydrogen production - An alternative clean energy source

Hydrogen generation from wastewater is one of the promising approaches through biological route. So, exploitation of wastewater as substrate for hydrogen production with concurrent wastewater treatment is an attractive and effective way of tapping clean energy from renewable resources in a sustainable approach. In this direction, considerable interest is observed on various biological routes of hydrogen production using bio-photolysis, photo fermentation and heterotrophic dark fermentation process or by a combination of these processes. Therefore, in this communication, utilizing industrial wastewater as primary substrate for dark fermentation process is reviewed and different parametric aspects associated with this sustainable approach for better energy production is discussed. The industrial wastewaters that could be the source for bio hydrogen generation, such as rice slurry wastewater, food and domestic wastewaters, citric acid wastewater and paper mill wastewater, are also discussed in this article.     

Development of embedded piezoelectric acoustic sensor array architecture

This paper examines development of novel piezoelectric acoustic sensors, which are capable of sensing high frequency acoustic emissions in a composite/metallic plate. The fabrication of the piezoelectric acoustic sensors, made from piezoceramic ribbons, is described in the paper. An attempt was made to build directionality into the sensing system itself. Continuous sensors placed at right angles on a plate are discussed as a new approach to measure and locate the source of the acoustic waves. Novel signal processing algorithms based on bio-inspired neural systems for spatial filtering of large numbers of embedded sensor arrays in laminated composite media are presented. It is expected that the present work would help in the development of microelectronic sensing aiding diagnostics and prognostics techniques for highly efficient health monitoring of integrated aerospace vehicles and structures.     

A Comparative Study of Corrosion Resistance in Ringer Solution of Nitrogen-Implanted Alumina at Different Energies for Orthopedic Implants

Commercially available polycrystalline alumina is implanted at different energies and various ion doses. Microstructural changes, elemental analysis, and evidence of compound formation of AlN and AlON are observed using scanning electron microscopy, electron dispersive X-ray spectroscopy, and GXRD techniques, respectively. Nanohardness increases due to the formation of the hard phase of nitrides. It increases with the increase in ion dose but decreases at higher ion dose. A similar trend is also observed in the corrosion resistance studied in Ringer solution. Corrosion resistance also improves with the increase in ion dose and decreases with the further increasing ion dose.     

Efficient Multiscale Modeling Framework for Triaxially Braided Composites using Generalized Method of Cells

In this paper, a framework for a three-scale analysis, beginning at the constituent response and propagating to the braid repeating unit cell (RUC) level, is presented. At each scale in the analysis, the response of the appropriate RUC is represented by homogenized effective properties determined from the generalized method of cells micromechanics theory. Two different macroscale RUC architectures are considered, one for eventual finite-element implementation and the other for material design, and their differences are compared. Model validation is presented through comparison to both experimental data and detailed finite-element simulations. Results show good correlation within range of experimental scatter and the finite-element simulation. Results are also presented for parametric studies varying both the overall fiber volume fraction and braid angle. These studies are compared to predictions from classical lamination theory for reference. Finally, the multiscale analysis framework is used to predict the onset of failure in a transversely loaded triaxially braided composite. The predicted transverse failure initiation stress value shows excellent correlation and provides the bound for which linear elastic constitutive models are acceptable for implementation.     

Sensitivity Analysis of the Ampacity,Cable and System Losses of 345 kV Pipe-Type Cable Systems

ABSTRACT

The affects of various parameters on the ampacity, cable and system looses of 345 kV oil-paper insulated naturally-cooled and forced cooled cable systems are considered and the sensitivity values are tabulated. The parameters which are of significance from the ampacity increase and energy conservation point of view are identified.     

A Practical Model for Generator Maintenance Scheduling with Transmission Constraints

In this paper an optimal maintenance scheduling of generating units in a power system has been developed with transmission network representation. Here a DC load flow has been embedded in the maintenance model to include network constraints resulting in a more practical maintenance schedule. The model developed here uses the minimization of system cost (production cost plus the unserved energy cost) as the objective criterion, whereas the reliability objective function used is the minimization of unserved energy. The optimization is achieved by integer linear programming. The incorporation of transmission network adds significant complexity to maintenance scheduling. The proposed model enables almost all practical maintenance scheduling constraints to be handled easily. The optimization has been carried out to minimize the cost function considering different cases (i.e., with and without incorporation of the transmission network). The effectiveness of the proposed method has been demonstrated by obtaining numerical results on sample and real scale test systems. A comparison of the cost objective function clearly indicates that the maintenance schedule obtained from the simple generation model alone is more expensive than the one with transmission, and that there is a considerable degree of suboptimality in the former case.     

Economic Dispatch Accounting Line Flow Constraints Using Functional Link Network

This paper presents a methodology for economic dispatch accounting line flow constraints in base case conditions. Functional Link Network (FLN) developed by Pao in 1989 has been used for this purpose. This single layer network has been trained using delta rule. Training set data have been obtained using Davidon-Fletcher-Powell's (DFP) method accounting inequality constraints by exterior penalty function method. An optimal brain damage technique has been employed for truncation and elimination of small weights. The algorithm is tested on IEEE 6-bus and 14-bus test systems.     

Progressive resistance training during hemodialysis: rationale and method of a randomized-controlled trial

Skeletal muscle wasting in patients receiving maintenance hemodialysis (HD) has been well documented. The rationale for prescribing progressive resistance training (PRT) in this cohort in an attempt to reverse this catabolism and induce a wide spectrum of physiological, functional, and psychological health-related adaptations is extremely strong. Unfortunately, the barriers to exercise adoption in this cohort are many, which may explain the persisting sedentariness of this population and the lack of widespread clinical programs such as are now commonplace in cardiac rehabilitation and pulmonary rehabilitation units. Current health care practices for HD patients do not address the negative health issues of inactivity and muscle wasting. Therefore, we conducted the first randomized-controlled trial to prescribe PRT during maintenance HD treatment. The purpose of this paper is to present the rationale and methodology that we utilized for implementing intradialytic PRT in a conventional outpatient HD clinic. Potential areas for modification of PRT regimens in this setting are also presented.     

Production of L(+) lactic acid from sweet sorghum,date palm,and golden syrup as alternative carbon sources

Lactic acid production has been carried out using (a) Lactobacillus delbruckii, (b) optimal production medium comprised of 10% carbon source derived from sweet sorghum (SS) (Sorghum bicolor)/golden syrup (GS; molasses after glucose crystallization)/date palm (DP) juice (Phoenix dactylifera L.), 1% yeast extract, 0.6% sodium acetate, 0.5% KH₂PO₄, and 0.5% MgSO₄ · 7H₂O, (c) in batch mode, (d) at 45 ± 1°C, 150 rpm, anaerobic condition, and pH 5.5 ± 0.1, and (e) sterilized CaCO₃ powder at regular intervals for neutralization to promote optimal utilization of sugar. The lactic acid (LA) productivity was higher from the use of GS and less from SS as well as DP juice. Decolorization of carbon sources prior to use in fermentation gave LA, meeting food grade specifications.