Synthesis and applications of ceramic (silicon carbide and silicon nitride), metallic (cobalt(0)) and polymeric (polyurethane) aerogels

A new method has been demonstrated for the synthesis of monolithic ceramic and purely metallic aerogels from xerogel powder compacts, and the use of polyurethane aerogels based on cyclodextrins as efficient desiccants. I. Highly porous ( \u3e 80%) monolithic SiC and Si3N4, aerogels were prepared from compressed compacts of polyurea-crosslinked silica xerogel powders. The process is time efficient as solvent-exchange through powders is fast, and energy efficient as it bypasses drying with supercritical fluids. The final ceramic objects were chemically pure, sturdy, with compressive moduli at 37 ±7 MPa and 59 ± 7 MPa, and thermal conductivities at 0.163 ± 0.010 W m-1 K-1 and 0.070 ± 0.001 W m-1 K-1, for SiC and Si3N4, respectively. II. Monolithic metallic Co(0) aerogels, synthesized from polyurea-crosslinked cobaltia xerogel powder compacts, were porous (69% v/v) and extremely sturdy (compressive modulus at 688 ± 10 MPa). They were infiltrated with molten LiClO4, and were ignited with a hot NiCr wire. The temperature during combustion reached 1515 °C. The heat released (-55.17 ± 2.01 kcal mol-1) was near the theoretical value for the reaction: 4 Co + LiClO4 ----\u3e 4 CoO + LiCl (-58.5 kcal mol-1). III. Polyurethane (PU) aerogels are low-density hierarchical nano-structured solids with high open nanoporosity, and high surface areas. Using α- and β-cyclodextrin (CD) as polyols, an aromatic triisocyanate and dibutyltin dilaurate (DBTDL) as a catalyst we obtained hyperbranched CD-based polyurethane aerogels (α- and β-CDPU-xx). Those materials show high water uptake capacities (108% w/w with α-CDPU-2.5) and can be reused multiple times by regeneration at room temperature by changing the relative humidity of the environment --Abstract, page v

Energy Optimisation in Office Buildings Through Daylighting Design for Climatic Conditions of Central India

This paper is based on the premise that energy optimisation is possible in office buildings through design of daylighting. The motivation for the study was born of the fact that in India, among all building typologies, commercial buildings consume the maximum energy. This energy consumption is mainly for cooling of the building and lighting the interior spaces. Cooling and lighting up spaces generates heat in and around the building, which again increases the cooling load. Out of the total electrical energy required in the building, around 20-40% is used for lighting purposes. Despite availability of daylight during the working hours, artificial lighting is used in offices that have huge internal spaces with large spans. This paper aims at understanding the factors related to daylight penetration into office building in different situations and developing guidelines for achieving maximum daylight penetration in large spaces

Microfluidic paper based membraneless biofuel cell to harvest energy from various beverages

The present work establishes the cost-effective and miniature microfluidic self-pumping paper based enzymatic biofuel cell (P-EBFC). The developed Y-shaped P-EBFC consists of buckeye composite multiwall carbon nanotube (MWCNT) buckypaper (BP) based bioanode and bio-cathode that were immobilized with electro-biocatalytic enzymes glucose oxidase (GOx) and laccase, respectively. The electrocatalytic activity of enzymes on electrode surface is confirmed using cyclic voltammetry (CV) technique. Such immobilized bio-anode and bio-cathode show exquisite electrocatalytic activity towards glucose and O2, respectively. Most appealingly, P-EBFC can directly harvest energy from widely available beverages containing glucose such as Mountain Dew, Pepsi, 7up and fresh watermelon juice. This could provide potential application of P-EBFC as a portable power device

To Develop and Implement Low Power, High Speed VLSI for Processing Signals using Multirate Techniques

Multirate technique is necessary for systems with different input and output sampling rates. Recent advances in mobile computing and communication applications demand low power and high speed VLSI DSP systems [4]. This Paper presents Multirate modules used for filtering to provide signal processing in wireless communication system. Many architecture developed for the design of low complexity, bit parallel Multiple Constant Multiplications operation which dominates the complexity of DSP systems. However, major drawbacks of present approaches are either too costly or not efficient enough. On the other hand, MCM and digit-serial adder offer alternative low complexity designs, since digit-serial architecture occupy less area and are independent of the data word length [1][10]. Multiple Constant Multiplications is efficient way to reduce the number of addition and subtraction in polyphase filter implementation. This Multirate design methodology is systematic and applicable to many problems. In this paper, attention has given to the MCM & digit serial architecture with shifting and adding techniques that offers alternative low complexity in operations. This paper also focused on Multirate Signal Processing Modules using Voltage and Technology scaling. Reduction of power consumption is important for VLSI system and also it becomes one of the most critical design parameter. Transistorized Multirate module which has full custom design with different circuit topology and optimization level simulated on cadence platform. Multirate modules are used AMI 0.6 um, TSMC 0.35 um, and TSMC 0.25 um technologies for different voltage scaling. The presented methodology provides a systematic way to derive circuit technique for high speed operation at a low supply voltage. Multirate polyphase interpolator and decimator are also designed and optimized at architectural level in order to analyze the terms power consumption, area and speed. DOI: 10.17762/ijritcc2321-8169.150314

Glycosylated hemoglobin as an efficacious tool for early prediction of gestational diabetes mellitus

The incidence and prevalence of GDM is on the rise worldwide and, more so in developing countries including India. GDM is associated with maternal, fetal and neonatal morbidities. Current guidelines recommend GDM screening only at 24-28 weeks of gestation. Diagnosis of GDM in later half of pregnancy leads to fetal and maternal morbidities in spite of good glycemic control. This necessitates the use of a simpler, convenient, accurate, and reliable test, which can predict GDM in early gestation. Our article reviews the scope of using HbA1c for GDM and its efficacy in screening GDM

Occurrence of Gastrointestinal Helminths in rabbits with special Reference to Importance of Giardia spp. as Parasitic Zoonoses

The aim of this study was to detect Giardia spp. as zoonotic helminth as Giardiosis has been recognised as the one of the important parasitic  diarrhoea among children as cross transmission may occur between human  and rabbits. Other helminths in rabbits may causes ill health and sometimes proved fatal. Faecal samples of 42 rabbits of different age group (1-4 years)  from Nagpur and Akola regions, India were examined. The study was  conducted during June to August 2008. Faecal sample examination revealed  presence of mixed infection of eggs of parasites like Giardia spp. (19.04%), Trichostrongyle spp. (28.57%), Graphidium spp. (19.04%), Coccidia spp. (16.66%) and Passaluras spp. (14.28%)

Design of Cognitive Radios

Cognitive radios are expected to perform spectrum sensing and communication in the frequency range of tens of megahertz to about 10 GHz. As such, they pose tough architecture and circuit design problems. This paper deals with issues such as broadband, low-noise amplification, multidecade carrier frequency synthesis, and spectrum sensing. The paper also describes the effect of nonlinearity and local oscillator harmonics, demonstrating that cognitive radios entail more difficult challenges than do software-defined radios. Multi-decade synthesis techniques and RF-assisted sensing methods are also presented

Thyroid dysfunction in women with polycystic ovarian syndrome: a comparative study

Background: Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in reproductive age women. Some of the PCOS women show presence of hypothyroidism.Methods: This study was conducted at tertiary care centre Indira Gandhi Government Medical College and Hospital (IGGMC), Nagpur, Maharashtra, India. The study group had 50 diagnosed patients of PCOS and 50 age matched normal regular menstruating women were taken as controls.Results: In this study, PCOS patients showed higher mean TSH level than control group (4.024±1.09 and 2.84±0.83 respectively). And more women were diagnosed with overt hypothyroidism in the PCOS group (6%) than in the control group (2%).Conclusions: The findings of the study showed that PCOS is associated with hypothyroidism as compared to normal population