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In this paper studies on the lab formulated fritless silver thick film paste with two different binder compositions that have been used to fabricate λ/2 microstrip rejection filter in the X and Ku band are reported. These have been compared with ESL (USA) paste and copper thin film metallization for the same circuit. The thick film circuits were overlayed with TiO₂ thick film of different thickness and changes in the characteristics studied. In the X band, the Q of the filter improves with overlay and is also dependent on the Ag paste formulation, whereas in the Ku band there are no thick film paste dependent properties observed due to overlay. Thickness of overlay and metallization paste formulation dependent factors should be taken into consideration during fabrication of high density and multi‐layer microwave integrated circuits.

Resource discovery in peer‐to‐peer (P2P) systems have been extensively studied. Unfortunately, most of the systems studied are not designed to take advantage of the heterogeneity in peer nodes. In this paper, we propose a novel P2P overlay called RATTAN, which serves as an underlay of a Gnutella‐like network. RATTAN exploits the heterogeneity of peer nodes by structuring capable nodes as the core of the overlay. Using a tree‐like structure, RATTAN can maximize the search scope with a minimal number of query messages. We evaluate RATTAN with simulation. The experiments show the following interesting results. First, RATTAN is robust by exploiting redundant overlay links. Second, the maximum bandwidth demand for processing the protocol of a single RATTAN overlay is nearly 1M bits/sec. However, around 80% of the nodes merely take 66 bits/sec. One implication is that we can use a small number of relatively capable peers (e.g., stable machines with a 100M bits/sec network interface) to process the 1M bits/sec protocol overhead and serve other peers that only need to spend 66 bits/sec for processing protocol overhead.

The ultra-thin white topping (UTW) is a cement concrete overlay of the thickness of 50–100 mm on bituminous concrete pavements with surface failures. This is a long-lasting solution without having short-term failures. This paper aims to design an ultra-thin cement concrete overlay using a developed critical stress model with sustainable concrete materials for low-volume roads.

In this research paper, a parametric study was conducted using the ultra-thin concrete overlay finite element model developed with ANSYS software, considering the significant parameters affecting the performance and development. The non-linear regression equation was formed using a damped least-squares method to predict critical stress due to the corner load of 51 kN.

The parametric study results indicate that with a greater elastic modulus of bituminous concrete, granular layer along with 100 mm thickness of concrete layer reduces the critical corner stress, interface shear stress in a significant way responsible for debonding of concrete overlay, elastic strains in the pavement further the concrete overlay can bear infinite load repetitions. From validation, it is understood that the non-linear regression equation developed is acceptable with similar research work done.

From the semi-scale experimental study, it is observed that the quaternary blended sustainable concrete overlay having a high modulus of rupture of 6.34 MPa is competent with conventional cement concrete overlay in terms of failure load. So, concrete overlay with sustainable materials of 100 mm thickness and higher elastic modulus of the layers can perform in a sustainable way meeting the environmental and long-term performance requirements.

The purpose of this paper is to compare thick and thin film microstripline response to conducting overlay.

Study changes in transmission and reflection of both thick and thin film microstripline due to overlay of polyaniline (PANI) thin film on stainless steel and silver. PANI was deposited by electropolymerisation method using HCl and H₂SO₄.

Transmittance of both the thick and thin film microstripline decreases due to the PANI overlay and reflectance increases. Thin film microstripline is more sensitive to the type of conducting overlay than thick film microstripline. PANI deposited on silver is more absorbing than PANI deposited on stainless steel using HCl acid. The overlay makes the response of the microstripline more dispersive.

The increase in reflectance and decrease in transmittance can provide information about the type of overlay materials. There is need for newer materials which can replace traditional metals for microstrip components. PANI might serve this purpose.

Peer‐to‐peer (P2P) streaming quickly emerges as an important application over the internet. A lot of systems have been implemented to support peer‐to‐peer media streaming. However, some problems still exist. These problems include non‐guaranteed communication efficiency, limited upload capacity and dynamics of suppliers which are all related to the overlay topology design. The purpose of this paper is to propose a novel overlay construction framework for peer‐to‐peer streaming.

To exploit the bandwidth resource of neighboring peers with low communication delay, application of the grouping method was proposed to construct a flexible two‐layered locality‐aware overlay network. In the proposed overlay, peers are clustered into locality groups according to the communication delays of peers. These locality groups are interconnected with each other to form the top layer of the overlay. In each locality group, peers form an overlay mesh for transmitting stream to other peers of the same group. These overlay meshes form the bottom layer of the overlay.

Through simulations, the performance was compared in terms of communication efficiency, source‐to‐end delivery efficiency and reliability of the delivery paths of the proposed solution currently. Simulation results show that the proposed method can achieve the construction of a scalable, efficient and stable peer‐to‐peer streaming environment.

The new contributions in this paper are a novel framework which includes the adaptability, maintenance and optimization schemes to adjust the size of overlay dynamically according to the dynamics of peers; and considering the importance of locality of peers in the system.

This paper reports the preliminary investigations on the effect of Bi2O3, Al2O3 and MgF2 thick film overlays on a symmetrical branch line microstrip directional coupler with a 3 db power split at 9.0 GHz. The changes in isolation and coupling with overlay thickness varying from 200 µm to 3000 µm were studied. It was observed that, for an overlay thickness of 200 µm to 600 µm, there was a 900 MHz bandwidth broadening with 3 db power split irrespective of the overlay material. The isolation also increased. Above 700 µm thickness an oscillatory behaviour was observed in the coupled ports with a decrease in coupling after about 10.5 GHz. The isolation characteristic of the 3 db directional coupler showed dependence on thickness as well as permittivity. It is felt that, with a suitable choice of dielectric material of appropriate thickness, an improved broadband coupling and high isolation may be realised by a simple overlay technique.

This paper reports the behaviour of a parallel coupled band pass microstrip filter due to an Al₂O₃ thin film‐thick film overlay and the effect of the moisture ambient on the properties of the overlaid microstrip filter. The thickness of the initial thin‐film overlay affects the behaviour of the filter after thick‐film overlay. Moisture has the effect of lowering the transmittance drastically and shifting the pass band to the lower frequency end. The filter loses its band pass characteristics after a few moisture‐heat cycles, indicating irreversible change taking place in the overlay material. It is felt that the ageing aspects of the overlay material should be taken into account when using dielectric overlays for circuit protection and cross‐over insulation purposes.

Use of thin film microstrip patch antenna for leaf moisture studies.

In this paper, the studies on the effect of leaf used as in‐touch overlay on thin film microstrip patch antenna in the X band (8‐12 GHz) is reported. The patch was used as the transmitting antenna and a pyramidal horn antenna was the receiving antenna. Three leaves Furcarea Gigantea, Kalanchoe Pinnata and Cereus Prerogonus have been used as overlay. All these leaves have high chlorophyll content, but are different in their surface texture and rate of moisture loss.

Size of leaf, orientation with respect to direction of propagation and moisture content dependent changes in the patch antenna output are observed. When the size of the overlay is larger than the patch and the feedline is in contact with it, frequency changes are more, whereas when only patch is in contact with the leaf, amplitude changes are more. Thin film microstrip antenna can provide a means for sensing moisture content in leafy vegetation.

The study of moisture effects of leafy vegetation using the technique of in‐touch overlay on microstrip components can be used to generate data base about the plant conditions in various places.

This paper aims to study tuning effects on thick film microstripline due to ferrite thick film overlay.

The possibility of obtaining tuning characteristics in the Ku band microwave region in the absence of external magnetic field by a simple process of using Ni_xZn_1−xFe₂O₄ thick film and bulk as in‐touch overlay over Ag thick film microstripline was investigated. The microstripline is basically a non‐resonant component with high‐transmission at a large microwave frequency band. The ferrite was synthesized by precursor method and the thick films were deposited by screen printing.

It was found that tuning characteristics were observed and composition, thickness and precursor dependent changes occurred. The changes with composition are more prominent in the 14.5‐16.5 GHz range. Also, the ferrite thick film overlay produces a deep notch at 15.7 GHz. It is observed that the pellet overlay also makes the microstripline very dispersive with a high‐insertion loss in the 16‐17 GHz range. The presence of permeability‐related effects interfering with the normal propagation of the microstrip circuits might be causing the changes in the circuits.

Owing to the Ni_xZn_1−xFe₂O₄ overlay the simple microstripline can be tuned to have narrow band filter type of characteristics. Thick film Ni_xZn_1−xFe₂O₄ overlay gives the added advantage of planer configuration along with cost‐effectiveness in the absence of magnetic field.

The purpose of this paper is to predict permittivity of leafy vegetation using overlay technique.

The paper studies X band moisture dependent microwave permittivity of the stem and leaf of Ficus Bengalensis using overlay on Ag thick film microstripline. The perturbation obtained in the transmission and reflectance of the thick film microstripline due to the leafy vegetation overlay has been used to obtain the permittivity.

The paper finds that the permittivities obtained are in the range expected of leafy vegetation with moisture. Only the amplitude data have been used here. As the moisture content decreases, the dielectric constant and dielectric loss decrease. The return loss characteristics show interesting frequency dependent behaviour due to both stem and leaf overlay.

The paper is original in that a non‐resonant microstrip component has been used for the first time for such studies. The thick film component along with overlay can be a cost‐effective dielectric sensor especially for biomaterials, since any size and shape of the overlay can be used.