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The design, analysis, fabrication, and testing of a four-port multiple-input multiple-output (MIMO) antenna is reported in this paper for automotive communications. The MIMO antenna is constructed using the basic antenna element exploiting a slot geometry. Two such antennas are developed on the same microwave laminate to develop a two-port MIMO antenna. Two such microwave laminates are interlocked to create the four-port MIMO scheme. The most distinct feature of the proposed architecture is that the inter-port isolation is well-taken care without the need for an external decoupling unit. The four-port MIMO antenna has an overall volume of 32 × 15 × 32 mm3. The prototype MIMO antenna is fabricated and the measurements are carried out to validate the simulation results. The antenna offers ultra-wideband (UWB) characteristics covering the frequency range of 2.8–9.5 GHz. The average boresight gain of the antenna ranges from 3.2 to 5.41 dBi with the peak gain at 8 GHz. The simulated efficiency of the antenna is greater than 73% within the operating bandwidth. The MIMO parameters such as envelope correlation coefficient, diversity gain, and mean effective gain are evaluated and presented. The appropriateness of the proposed antenna for deployment in the shark fin housing of the present-day automobiles is verified using on-car performance estimation.
We monitored native forest regeneration over 11 y in a eucalyptus plantation and compared it with the neighbouring primary forest. For the plantation forest, we hypothesized that species richness, density, basal area and densities of old-growth species would increase over time, and compared to the primary forest, plantation forest would have higher species richness and density, but lower densities of old-growth species. In 2016, we repeated the protocol of a study that sampled the plantation forest in 2005, with thirty 10 × 10-m plots and enumerating trees (≥10 cm diameter), saplings (>1 to <10 cm diameter) and seedlings (<1 cm diameter). In the plantation forest, for trees, the species richness, density of gap, bird-dispersed and mammal-dispersed species increased by 67%, 156%, 116% and 238% respectively; whereas for saplings, density of gap, bird-dispersed and small-seeded species declined by 45.2%, 51% and 18.2% respectively over time; and seedling densities did not change across functional groups. Stand basal area increased by 80.1% in the plantation forest. The primary forest had 446% greater density of closed-canopy trees compared with plantation forest. Contrary to our prediction, the plantation forest did not accumulate significant densities of old-growth species over time, probably due to demographic filters that prevent them from attaining maturity.
Because obesity is associated with many co-morbidities, including diabetes mellitus, this study evaluated the second-meal effect of a commercial prebiotic, inulin-type fructans, and the effects of the prebiotic on faecal microbiota, metabolites and bile acids (BA). Nine overweight beagles were used in a replicated 3×3 Latin square design to test a non-prebiotic control (cellulose) against a low (equivalent to 0·5 % diet) and high dose (equivalent to 1·0 % diet) of prebiotic over 14-d treatments. All dogs were fed the same diet twice daily, with treatments provided orally via gelatin capsules before meals. On days 13 or 14 of each period, fresh faecal samples were collected, dogs were fed at 08.00 hours and then challenged with 1 g/kg body weight of maltodextrin in place of the 16.00 hours meal. Repeated blood samples were analysed for glucose and hormone concentrations to determine postprandial incremental AUC (IAUC) data. Baseline glucose, insulin and active glucagon-like peptide-1 levels were similar between all groups (P>0·10). Glucose and insulin IAUC after glucose challenge appeared lower following the high dose, but did not reach statistical relevance. Prebiotic intervention resulted in an increase in relative abundance of some Firmicutes and a decrease in the relative abundance of some Proteobacteria. Individual and total faecal SCFA were significantly increased (P<0·05) following prebiotic supplementation. Total concentration of excreted faecal BA tended to increase in dogs fed the prebiotic (P=0·06). Our results indicate that higher doses of inulin-type prebiotics may serve as modulators of gut microbiota, metabolites and BA pool in overweight dogs.
The present study investigates the behaviour of the shock train in a typical Ramjet engine under the influence of shock and expansion waves at the entry of a low aspect ratio (1:0.75) rectangular duct/isolator at supersonic Mach number (M = 1.7). The start/unstart characteristics are investigated through steady/unsteady pressure measurements under different back and dynamic pressures while the shock train dynamics are captured through instantaneous Schlieren flow visualisation. Two parameters, namely pressure recovery and the pressure gradient, is derived to assess the duct/isolator performance. For a given back pressure, with maximum blockage (9% above nominal), the duct/isolator flow is established when the dynamic pressure is increased by 23.5%. The unsteady pressure measurements indicate different scales of eddies above 80 Hz (with and without flap deflection). Under the no flap deflection (no back pressure) condition, the maximum fluctuating pressure component is 0.01% and 0.1% of the stagnation pressure at X/L = 0.03 (close to the entry of the duct) and X/L = 0.53 (middle of the duct), respectively. Once the flap is deflected (δ = 8°), decay in eddies by one order is noticed. Further increase in back pressure (δ ≥ 11°) leads the flow to unstart where eddies are observed to be disappeared.
In vitro rumen methane output (IRMO) of over 200 feed/feed mix samples representing approximately 74 feed types was investigated in a series of completely randomized experiments. The samples comprised dry fodder, grass, tree leaves, cultivated grasses, cereal by-products, cereal grains, oilseed/meals, compound feeds and total mixed rations (TMRs) from the tropical regions. These samples were subjected to three in vitro gas production tests at 39 °C in 100 ml Heberle syringes. The first incubation was conducted with 200 mg dry matter (DM) substrate for 96 h to determine half-time gas production (t1/2, h) value of each sample. The second and third incubations were carried out simultaneously. The second incubation was done with 200 mg DM substrate until t1/2 time to determine IRMO and third with 500 mg DM to estimate in vitro dry matter digestibility (IVDMD) of each samples, respectively. The IRMO was expressed as ml/100 mg digestible substrate. Crude protein content (g/kg DM) was lowest in dry fodder samples and highest in oilseed meals, whereas it was similar in local grass and tree leaves. The IVDMD values ranged from 0·48 to 0·87; the lowest digestibility was recorded in tree leaves. The potential gas production (PGP, ml/200 mg DM) ranged from 9·76 to 61·3. The PGP from grasses and compound feeds was similar, whereas it was lowest in tree leaves. The rate constant (mg/h) was maximum in compound feed followed by oilseed meal. The rate constant was similar among other group of feedstuffs. The t1/2 time ranged from 9·8 to 19·4 h. The highest t1/2 time was recorded in local grass samples followed by dry fodder and cultivated grasses. However, they were similar among tree leaves, cereal grains, by-products and compound feeds. The methane % in the total gas varied from 9·79 (tree leaves) to 20·2 (local grasses). Among straw, IRMO varied from 3·88 (Zea mays fodder) to 12·0 (Sorghum vulgare) and it was lower in fruit tree leaves than cultivated grasses. Among protein and energy sources, IRMO was higher in cereal by-products as compared with cereal grains, oil meals and compound feed. The IRMO was similar among TMR, irrespective of the composition of the concentrate mixture. Nevertheless, it varied with the amount of concentrate in the TMR. This is the first exhaustive data on IRMO from the tropical region. Because of the substantial amount of dietary gross energy lost in methane, knowledge of the methane output from these feed ingredients will help in formulating low methane emitting diets for ruminants. Incorporation of tropical tree leaves in the diets and feeding TMR are potential strategies to reduce enteric methane emission in ruminants.
An attempt to reduce the effect of major toxic components namely phosphine ligands and unsaturated solvents as being used in conventional nanocrystal synthesis, has been made with a new binary ligand, and a reusable solvent N-octadecane for a smokeless and clean synthesis procedure. The optimized effects of the two ligands oleic acid and octadecyl amine on the nucleation rate and growth of CdSe nanocrystals (NCs) are reported and substantiated by AFM analysis. Oleic acid accelerates particle ripening and nuclei growth, but inhibits nucleation whereas octadecyl amine catalyses nucleation and very gradually improves growth to obtain small stable NCs. Another important feature of the present study is the replacement of 1-octadecene by a competitive N-octadecane as a solvent in such ligand mediated nanocrystal synthesis. The GCMS analysis reports a recovery of 95% of solvent after reuse, thus opening a scope for environmental friendly processes.
The positioning of a wheeled robot is an imperative manipulation problem in mobile robotics. Odometry is a familiar method for determining the relative position of a mobile robot. It comprises the detection of a set of kinematic parameters that permit reconstructing the robot's absolute position and orientation starting from the wheels' encoder measurements. This paper deals with the determination of better relative localization of a mobile robot by means of odometry by considering the influence of parameters namely total weight, speed, diameter of wheel, and width of wheel. Experiments have been conducted based on L9 orthogonal array suggested in Taguchi method to obtain the optimum condition. A mathematical model has also been developed for the mobile robot with the help of MINITAB software.
In the present study, we report the enhancement in figure-of-merit (ZT) of nanostructured n-type Silicon-Germanium (Si80Ge20) thermoelectric alloy synthesized using high energy ball milling followed by spark plasma sintering (SPS). After 90 h of ball milling of elemental powders of Si, Ge and P (2 at.%), a complete dissolution of Ge in Si matrix has been observed forming the nanostructured n-type Si80Ge20 alloy powder. X-ray diffraction analysis (XRD) confirmed the crystallite size of the host matrix (Si) to be ∼7 nm and also indicated the formation of an additional phase of SiP nano-precipitates after SPS. HR-TEM analysis revealed that the nano-grained network was retained post-sintering with a crystallite size of size of 9 nm and also confirmed the SiP precipitates formation with a size of 4 to 6 nm. As a result, a very low thermal conductivity of ∼2.3W/mK at 900°C has been observed for Si80Ge20 alloy primarily due to scattering of phonons by nanostructured grains and nano-scaled SiP precipitates which further contribute to this scattering mechanism. Electrical conductivity values of SiGe sintered alloy are slightly lower to that of reported values in literature. This was attributed to the formation of SiP which creates a compositional difference between the grain boundary region and the grain region, leading to a chemical potential difference at interface and the grain region. Figure-of-merit (ZT) of n-type Si80Ge20 nanostructured alloy was found to be ≈1.5 at 900°C, which is the highest reported so far at this temperature.
A general new methodology using evolutionary algorithms viz., Elitist Non-dominated Sorting Genetic Algorithm (NSGA-II) and Multi-objective Differential Evolution (MODE), for obtaining optimal trajectory planning of an industrial robot manipulator (PUMA 560 robot) in the presence of fixed and moving obstacles with payload constraint is presented. The problem has a multi-criterion character in which six objective functions, 32 constraints and 288 variables are considered. A cubic NURBS curve is used to define the trajectory. The average fuzzy membership function method is used to select the best optimal solution from Pareto optimal fronts. Two multi-objective performance measures namely solution spread measure and ratio of non-dominated individuals are used to evaluate the strength of Pareto optimal fronts. Two more multi-objective performance measures namely optimiser overhead and algorithm effort are used to find computational effort of the NSGA-II and MODE algorithms. The Pareto optimal fronts and results obtained from various techniques are compared and analysed. Both NSGA-II and MODE are best for this problem.
Gyps vulture populations across the Indian subcontinent collapsed in the 1990s and continue to decline. Repeated population surveys showed that the rate of decline was so rapid that elevated mortality of adult birds must be a key demographic mechanism. Post mortem examination showed that the majority of dead vultures had visceral gout, due to kidney damage. The realisation that diclofenac, a non-steroidal anti-inflammatory drug potentially nephrotoxic to birds, had become a widely used veterinary medicine led to the identification of diclofenac poisoning as the cause of the decline. Surveys of diclofenac contamination of domestic ungulate carcasses, combined with vulture population modelling, show that the level of contamination is sufficient for it to be the sole cause of the decline. Testing on vultures of meloxicam, an alternative NSAID for livestock treatment, showed that it did not harm them at concentrations likely to be encountered by wild birds and would be a safe replacement for diclofenac. The manufacture of diclofenac for veterinary use has been banned, but its sale has not. Consequently, it may be some years before diclofenac is removed from the vultures' food supply. In the meantime, captive populations of three vulture species have been established to provide sources of birds for future reintroduction programmes.
The Krishna Valley breed of cattle is a draught breed able to withstand extremely hot, humid climatic conditions and which has the capacity to undertake heavy work in the black cotton soil in the valleys of the Krishna river in India. Their home tract is restricted to a few taluks (divisions within a district) of the northern parts of Karnataka. The distinguishing morphological features of the breed are the presence of a black-coloured muzzle and black shades dispersed over the body with the lower half of the scrotum also being black in colour. The average values for height, body length and chest girth are 116.4±1.2, 128.4±2.0 and 144.7±2.0 cm in cows; and 150.5±0.5, 146.0±3.0 and 191.0±1.0 cm in bullocks, respectively. The cytogenetic investigation revealed the normal characteristics of cattle chromosomes (2n=60). The microsatellite alleles occurred at frequencies of 0.0208 (ILSTS005) to 0.7604 (ETH152) with the polymorphism information content (PIC) values in the range of 0.3856 (ETH152) to 0. 7725 (ILSTS034). The breed has a relatively long productive life as the number of calvings can go up to twelve. As the number of animals of this breed remaining is only in the order of a few hundred, conservation measures are to be taken to avoid the extinction of this valuable germplasm.
Food habits of Malabar Pied Hornbill Anthracoceros coronatus were studied from December 2000 to December 2001, in the Athikadavu valley, Western Ghats, India. A total of 147 individuals belonging to 18 fleshy-fruited tree species were monitored fortnightly. Thirteen fruit species, including five figs and eight non-figs, were recorded in the birds' diet. The overall number of tree species in fruit and fruiting individuals increased with the onset of summer, the Malabar Pied Hornbill's breeding season. The peak in fruiting is attributed to the peak in fruiting by figs. Figs formed the top three preferred food species throughout the year. During the non-breeding period (May to February), 60% of the diet was figs. During the peak breeding period (March and April), two nests were monitored for 150 hours. Ninety-eight per cent of food deliveries to nest inmates were fruits belonging to six species. Most fruits delivered at the nests constituted figs (75.6%). In addition, figs sustained hornbills during the lean season and should be considered “keystone species” in the riverine forest ecosystem. Two non-fig species are also important. Habitat features and local threats at Athikadavu valley were assessed. The distribution and conservation status of Malabar Pied Hornbill in the Western Ghats was reviewed. Conservation of hornbill habitats, particularly the lowland riparian vegetation, is imperative.
We investigate the evolution of nearby like-sign vortices whose
centres are at different
vertical levels in a stably stratified rotating fluid. We employ two differently
representations of the potential vorticity distribution in the quasi-geostrophic
equations (QG), in order to elucidate the pair-interaction behaviour previously
in non-singular QG numerical solutions. The first is an analytically tractable
(Hamiltonian) elliptical-moment model (EM) for thin-core vortices, which
exhibits a regime of very strong horizontal elongation of a vortex in response
strain induced by its partner. We interpret this as an early evolutionary
the irreversible dissipative merger and alignment interactions. This interpretation
is strengthened by weakly dissipative numerical solutions of a thin-core
model (CD), which exhibit even further progress towards the completion
of these vortex interactions in the same regime.
In the EM model we classify the co-rotating stationary states which exist
for vertically offset thin-core vortices. However, the mutual strain field
vortices cannot be balanced by co-rotation in a weakly elongated stationary
a certain class of neighbouring, but substantially non-aligned, vortex
and our interpretive assumption is that such configurations will rapidly
non-singular QG solutions towards a more aligned configuration through
non-conservative reorganizations of the potential vorticity field. Both
the EM and CD
models show qualitatively similar regime boundaries between evolutions
and strongly deformed vortices. In particular, there is a fairly close
between the occurrence of strong vortex elongation in the EM solutions
filamentation and splitting in the CD solutions.