Pulsed laser processing of dielectric materials

The thesis investigates the wavelength dependent laser ablation in dielectric materials used for the fabrication of high density Printed Circuit Boards (PCBs) in the electronics industry. Here the market for consumer and industrial products of ever-rising complexity has led to a demand for increased miniaturisation and low costs of multi- level printed circuit boards (PCBs) interconnected by microvias, which electrically connect the various circuit layers. Laser machining offers a potential solution to this need. The main objective of the research is to investigate the wavelength-dependence of the laser machining/drilling efficiency of two important sets of PCB materials, categorised as Organics and Ceramics using a carbon dioxide laser which can be tuned across its emission spectrum in the 9pm -II pin spectral region.. The organics include commercially available electronic materials with trade names such as Kapton, Arlon, FR4 and RCC and the ceramics materials studied are alumina and low temperature co- fired ceramic (LTCC). The aim is to determine the optimum laser wavelength for maximum processing efficiency i. e. to find the wavelength where the laser parameters are best matched to the optical, thermal and mechanical properties of each of the materials. A C02 laser machining system was constructed which incorporated a novel laser source developed in the research programmes. The laser source was a MOPA system with a line-tuneable cw oscillator and a five pass power planar waveguide rf discharge-excited power operating in the so-called enhanced power regime to produce maximum peak power. An Acousto-optic modulator between the master oscillator and the amplifier allowed convenient control of pulse amplitude and duration. The system enabled the wavelength dependent studies on the wavelength and pulse energy dependence of the laser ablation properties (e. g. ablation threshold fluence and ablation rates) - to derive the so-called 'ablation spectrum' of the selected materials A comparison is made of the wavelength dependence of ablation with the room temperature absorption spectrum measured for each material using ellipsometry. It was observed that the 'ablation spectrum' information does not always appear to match the simple expectations derived from the room temperature 'absorption spectrum' of the material. This disparity in results is likely due to the change of absorption properties of material because of rise in temperature, chemical decomposition or melting of material during ablation. However, the room temperature absorption spectrum (while not adequate alone), did provide a useful guide to the selection of a sub-set of the 40+ lines that would otherwise have to be studied. The results may be of direct application in the electronics industry to increase the efficiency of laser machinin

Path Loss Model for 2.4GHZ Indoor Wireless Networks with Application to Drones

Indoor wireless communication using Wireless Fidelity (Wi-Fi) is becoming a major need for the success of Unmanned Aerial Vehicles (UAVs), Internet of Things (IoT) and cloud robotics in both developed and developing countries. With different operating conditions, interference, obstacles and type of building materials used, it is difficult to predict the path loss components in an indoor environment, which are crucial for the network design. It has been observed that the proposed indoor path loss models cannot be used for UAV operations due to variations in building materials utilized, floor plans, scattering on both ends, etc. In this work, we propose a non-deterministic statistical indoor path loss model, namely, the UAV Low Altitude Air to Ground (U-LAAG) model, adapted from ITU-R model, which can be used for the 2.4 - 2.5 GHz, Industrial Scientific and Medical (ISM) band. To test and validate the proposed model, we conduct several experiments with different conditions such as University premise with obstacles, typical dwelling and basement locations. We have also compared U-LAAG with popular path loss models such as ITU-R, Two-ray and Log-distance; U-LAAG matches closely with the drive test results as compared to other models. We believe that the proposed ULAAG model can be used as basis to design accurate indoor communication networks required for regular Wi-Fi communications and deployment and operations of UAV, IoT and cloud robotics

Assessment Of The Performance Of Territories With Special Entrepreneurial Treatment

The article discusses the reasons for the low efficiency of territories activity with a special regime of doing business. One of the main reasons is the lack of a formalized desired image of the future of a special territory in the form of a system of key indicators. This situation leads to distortions in the implementation of management decisions. Currently, the needs of potential resident investors are put at the forefront, which leads to a conflict of interests of interested parties, depletion of resources and other negative consequences. Based on the proposed system of indicators, a method has been developed for assessing the effectiveness of the development of a particular territory, in which effectiveness is assessed as a system of private, key, integral and generalized (synergistic) indicators that reflect quantitative and qualitative changes in the development of the territory. From the perspective of the institutional- synergistic approach, the system of key performance indicators is presented in the form of two subsystems. The subsystem of performance indicators will describe the objective picture of the past and the present, and the subsystem of performance indicators will warn about future events (signals about risks and their consequences). The proposed subsystems of performance indicators for specific territories are formed using two types of feedback channels. The proposed models will allow us to move from fragmented control actions, aimed primarily at quantitative indicators to the synergistic development of the territory with a special regime of doing business

Regulation of L-type calcium channel sparklet activity by PKC and C-src

Title from PDF of title page (University of Missouri--Columbia, viewed on April 21, 2014).Ca2+ sparklets are elementary fluorescence events associated with Ca2+ entry through L-type Ca2+ channels (Cav1.2) channels and are classified as persistent and low activity Ca2+ sparklets. Persistent Ca2+ sparklets are characterized by longer and more frequent channel open events and account for approximately 50% of the steady state Ca2+ entry through Cav1.2 channels. Previous studies suggest that the alpha isoform of protein kinase C (PKCalpha]) underlies persistent Ca2+ sparklet activity, but the mechanism of PKC[alpha] action on Cav1.2 channels is unclear. c-Src, another highly expressed kinase in vascular smooth muscle, phosphorylates Cav1.2 to increase whole-cell Ba2+ current (IBa) but it remains unknown if c-Src induces persistent Ca2+ sparklet activity through Cav1.2 channels. Here, I addressed two questions: 1) Does c-Src produce persistent Ca2+ sparklets through Cav1.2c (the neuronal isoform of Cav1.2)? 2) Does PKC[alpha] activate c-Src to produce persistent Ca2+ sparklets? TIRF microscopy was used to record Ca2+ sparklets from voltage-clamped HEK 293T cells co-expressing wild type (WT) or mutant Cav1.2c + active or inactive PKC[alpha]/c-Src. The results indicate that c-Src produces persistent Ca2+ sparklet activity, which is significantly reduced in the presence of the c-Src inhibitor, PP2, or with overexpression of kinase-dead c-Src. I tested two potential c-Src phosphorylation sites (Y2122F and Y2139F) on Cav1.2c for their role in production of persistent Ca2+sparklets. The Y2122F mutation significantly reduced persistent Ca2+sparklet activity while the Y2139F mutation was without any effect, indicating that c-Src phosphorylates Cav1.2c at Y2122 to induce persistent Ca2+ sparklets. Y2122F and Y2139F mutations did not have any significant effect on persistent Ca2+ sparklets in cells expressing Cav1.2c + PKC[alpha], indicating that PKC[alpha] does not act upstream of c-Src to produce persistent Ca2+sparklets. Whether PKC[alpha] phosphorylates S1901, the classical PKA phosphorylation site, to produce persistent Ca2+sparklet activity remains to be resolved

A Comparativestudy On Present Education System In Haryana And Its Neighbouring States

India has the second largest education system in the world. The Indian education system has gone through many phases. Great effort has been put to shape up the present scenario of education system. The announcements like abolishing compulsory CBSE board exams for class 10th from the session 2010-11, introduction of grading system, the passage of Right of Children to free and Compulsory Education Bill, reservation policies etc. Are a few among them? Now the question arises as to what extent such efforts in the field of education have succeeded in different states of the country. Haryana is the state with a contribution of 3.7% in the total GDP of India. This present study will throw light on the education system of Haryana, with a comparative eye on its neighbouring states. An analysis of the educational achievements of these states from different angles will help the experts and the researchers to know how far we have gone in achieving our targets and what needs to be done. This paper is descriptive in nature, based on the data collected from different websites of ministry as well as reports of planning commission