Phytoplankton communities of a floodplain lake of the Brahmaputra River basin, Upper Assam

Phytoplankton (52 species; Bacillariophyceae>Chlorophyceae>Cyanophyceae> Euglenophyceae=Dinophyceae) of Samuajan beel, a tropical floodplain lake, registered identical mean annual richness (30+4 species) in littoral and limnetic regions and depicted 33.3-77.2% and 31.4-81.1% community similarities respectively. Their abundance ranged between 137+54 n/l in littoral (Bacillariophyceae>Chlorophyceae) and 122 ± 45 n/l (Chlorophyceae>Bacillariophyceae) in limnetic communities, comprised about 46% of net plankton and indicated winter peaks. This study depicted moderate species diversity, high evenness and low dominance of phytoplankton; species diversity showed significant direct correlation with richness and evenness and an inverse relationship with dominance. Phytoplankton showed significant positive relationship with transparency and silicate and negative with water temperature, rainfall, chloride and nitrate. Multiple regression revealed that ten abiotic factors accounted for >80-98% of density variations of phytoplankton and the dominant groups. ANOVA depicted trends of significance in abundance of the biotic communities analysed

On the taxonomic status of some cladoceran taxa (Crustacea : Cladocera) from Central India

La taxinomie et la validité de douze nouvelles espèces et d'une sous-espèce de Cladocères d'eau douce, décrites par RANE (1983-87) de l'état de Madhya Pradesh en Inde centrale, sont examinées et discutées. Leur distribution géographique est présentée. (Résumé d'auteur

The distribution of the Lecanid rotifers (Rotifera : Monogononta : Lecanidae) in North-Eastern India

Trente espèces (trente-deux taxons), du genre #Lecane, y compris #Lecane jaintianensi sp. n., de la province du Nord-Est de l'Inde sont examinées. Sept taxons sont nouveaux pour l'Inde et 30 sont nouveaux pour la région. Des éléments d'écologie et de distribution sont donnés. (Résumé d'auteur

Intermediate-range order in molten network-forming systems

Molecular Dynamics simulations using the polarisable ion model (PIM), which accounts for many-body ion polarisation in addition to short-range repulsion and simple Coulombic interaction between ions, are undertaken in a study of the structure of molten network-forming liquids. The primary focus is the investigation of the structural origin of intermediate range order (IRO), the ordering of atoms beyond the nearest-neighbour in liquids and glasses often highlighted by the presence of a first sharp diffraction peak (FSDP) in total and partial structure factors. Two primary modelling approaches are applied. In the first, specific systems of MX2 stoichiometry are targeted (ZnCl2, MgCl2 and GeSe2) allowing for direct comparison with the results from scattering experiments. An ionic description for GeSe2 represents a stern test as this system is often described as having considerable metallic character. In the second approach, key system parameters are systematically varied in order to control the network topology and examine the evolution of IRO. A key structural property, the presence of a FSDP in the concentrationconcentration structure factor, SCC(kFSDP), is observed and structure factors, “coloured” according to network connectivity, show its presence to be dependent on the percolation of edge-sharing units disturbing the corner-sharing tetrahedral network. The effect on the network topology and IRO of varying both temperature and pressure, properties often difficult to obtain experimentally, are observed. The inherent structure of the systems studied shows the presence of newly resolved features, including a distortion of constituent polyhedra. Homopolar bonds are induced by combining Morse and Born- Mayer potential and their effect on the underlying IRO examined

The Scenario of Carbonaceous Aerosols and Total Solar Radiation in Two Cities in Nepal

Measurement of elemental carbon (EC) and black carbon (BC) aerosols was carried out using AE-31, 7 channel aethalometer at Kathmandu and Biratnagar; two mega cities of Nepal, for five months, January to May 2011 to study its temporal and spatial variation. Total solar radiation was also monitored using Kipp and Zonen CMP 6 pyranometer. Monthly concentration variation for EC and BC was distinct in both study sites. At Biratnagar, monthly EC concentration varies from 3.3 -20.7 µg /m3 while in Kathmandu it varies between 6.0-13.7 µg /m3. Similarly, BC monthly concentration ranges from 3.3 -20.1 µg /m3 and 7.0-14.9 µg /m3 respectively. It was found that both EC and BC were highest during January in both the sites and it decreases gradually. Monthly average solar radiation shows a maximum value in May and minimum in January. A distinct anti-correlation between monthly average carbonaceous aerosols and total solar radiation was observed. Moreover, there was a pronounced diurnal variation of both carbonaceous aerosols EC and BC in the sites with two high peaks one in the morning at about 9:00 and another at late evening 20:00 local time with minimum concentration in the afternoon. The nature of peaks were different at two sites. Biratnagar shows a larger evening peak while Kathmandu shows in the morning inferring heavy domestic and industrial fuel consuming activities in evening and morning respectively. In addition to this, daily and monthly concentration of EC was more than BC at Biratnagar reflecting slightly more biomass fuel consumption than fossil fuel for domestic, industrial and other urban activities. In contrast to this, Kathmandu shows more domination of fossil fuel than biofuel because of reverse order concentration of carbonaceous aerosols. Total solar radiation also shows apparent diurnal variation in both sites with the highest value at around noon time

EFFECTS OF MEDU AND COASTAL TOPOGRAPHY ON THE DAMAGE PATTERN DURING THE RECENT INDIAN OCEAN TSUNAMI ALONG THE COAST OF TAMILNADU

Effects of Medu (naturally elevated landmass very close to the seashore and elongated parallel to the coast) and coastal topography on the damage pattern during the deadliest Indian Ocean tsunami of December 26, 2004 is reported. The tsunami caused severe damage and claimed many victims in the coastal areas of eleven countries bordering the Indian Ocean. The damage survey revealed large variation in damage along the coastal region of Tamilnadu (India).The most severe damage was observed in the Nagapattinam district on the east coast and the west coast of Kanyakumari district. Decrease of damage from Nagapattinam to Kanchipuram district was observed. Intense damage again appeared to the north of Adyar River (from Srinivaspuri to Anna Samadhi Park). Almost, no damage was observed along the coast of Thanjavur, Puddukkotai and Ramnathpuram districts in Palk Strait, situated in the shadow zone of Sri Lanka.It was concluded that the width of continental shelf has played a major role in the pattern of tsunami damage. It was inferred that the width of the continental shelf and the interference of reflected waves from Sri Lanka and Maldives Islands with direct waves and receding waves was responsible for intense damage in Nagapattinam and Kanyakumari districts, respectively. During the damage survey authors also noted that there was almost no damage or much lesser damage to houses situated on or behind the Medu. Many people observed the first arrival. The largest tsunami amplitude occurred as the first arrival on the eastern coast and in the second arrival on the western coast

Novel Catalyst for Breaking Down Lignin

It currently takes more energy to break down lignin—the cementing agent that binds the matrix of cellulose fibers of tough plant cell walls—than it is worth. However, ISTC has developed a novel catalyst that has shown promise for separating lignin into shorter polymers and monomers. The catalyst works at a much lower temperature than existing techniques, potentially making the process significantly cheaper. The optimum pretreatment strategy does not yet exist that can efficiently release sugars from the crystalline structure of cellulose and the more complex matrices of hemicellulose and lignin. That is because energy used to achieve sugar release dehydrates lignin, making it harder still to break it down. Several types of lignin have a market value of $50 to$500/tonne. But if biofuel producers could produce higher-value materials from lignin (> $1,000/tonne), biorefineries’ profits would greatly improve. Higher-value chemicals derived from lignin could replace petrochemicals used in manufacturing polyurethanes, polyesters, resins, and activated carbon. Carbon fibers used in cars, jets, and sporting goods might be produced more cheaply using lignin-derived materials. These materials could replace more metals in consumer products, with lasting environmental benefits.Ope

Advancing Use of Recycled Material in Asphalt

Recycled materials such as reclaimed asphalt pavement and recycled asphalt shingles are commonly used with new pavement to cut costs. However, the recycled materials tend to become brittle faster, cracking and aging more quickly than when all new materials are used. ISTC researchers led by B.K. Sharma are collaborating with the U of I Center for Transportation to determine how much recycled material can be used in asphalt materials while maintaining high performance and longevity. The research team for Phase I received the Illinois Center for Transportation/IDOT’s 2018 High Impact Research Award for their work in determining how long the asphalt with recycled materials would last. In Phase II, they will determine how much recycled material can be safely used without affecting the performance of the asphalt. By simulating conditions in the field, they can provide recommendations on how much recycled materials and what modifiers to use to decrease costs and increased sustainability. Phase II is funded by IDOT.Ope

Dry Etching of GaAs to Fabricate Via-Hole Grounds in Monolithic Microwave Integrated Circuits

This study investigates the dry etching of 60 mm dia, 200 mm deep holes for fabrication of through substrate via holes for grounding monolithic microwave integrated circuits (MMICs), on 3-inch dia semiinsulating GaAs wafer using RIE and ICP processes with CFC and non-CFC gas chemistry, respectively. The effect of various process parameters on GaAs etch rate and resultant etch profile was investigated. Two kinds of masks, photoresist and Ni, were used to etch GaAs and performance was compared by investigating effect on etch rate, etch depth, etch profile, and surface morphology. The etch profile, etch depth, and surface morphology of as-etched samples were characterised by scanning electron microscopy. The desired 200 mm deep strawberry profile was obtained at 40 mTorr for both RIE and ICP processes with an etch rate of ~1.3 mm/min and ~4 mm/min respectively. Ni metal mask was used for RIE process due to poor photoresist selectivity, whereas ICP process utilised photoresist as mask. The vias were then metallised by depositing a thin seed layer of Ti/Au (1000 Å) using radio frequency sputtering and Au (~5 mm) electroplated to connect the frontside pad and back side ground plane. The typical parasitic inductance offered by these via for RIE and ICP processes was ~76 pH and 83 pH respectively, which is well within the acceptable limits. The developed process was finally integrated to in-house MMIC production line.Defence Science Journal, 2009, 59(4), pp.363-370, DOI:http://dx.doi.org/10.14429/dsj.59.153

Security Issues and Challenges (SIC) of Ad-hoc Networking.

As the approach of ad hoc networking varies from traditional networking approaches, the security aspects that are valid in the conventional wired networks are not fully applicable in the context of ad hoc networks. While the basic security requirements such as confidentiality and authenticity remain, the ad hoc networking approach restricts the set of applicable security mechanisms to be used since the level of security and the performance are related to each other and must be carefully balanced. The security goals and challenges that the field of ad hoc networking faces are explored in more detail. An overview of the most important active attacks is included. Some of the most important security schemes are presented in order to illustrate common approaches that are currently followed to ensure network security in infrastructure less networks. The protected resourceful Ad hoc Distance vector routing protocol (SEAD)[2] employ the use of hash chains to substantiate hop counts and sequence numbers. SEAD[2] is based on the design of the proactive ad hoc routing protocol DSDV[9]. The final secure routing protocol to be presented is the Secure Routing Protocol (SRP)