Probing the loss origins of ultra-smooth Si3N4\mathrm{Si_3N_4} integrated photonic waveguides

On-chip optical waveguides with low propagation losses and precisely engineered group velocity dispersion (GVD) are important to nonlinear photonic devices such as soliton microcombs. Yet, despite intensive research efforts, nonlinear integrated photonic platforms still feature propagation losses orders of magnitude higher than in standard optical fiber. The tight confinement and high index contrast of integrated waveguides make them highly susceptible to fabrication induced surface roughness. Therefore, microresonators with ultra-high Q factors are, to date, only attainable in polished bulk crystalline, or chemically etched silica based devices, that pose however challenges for full photonic integration. Here, we demonstrate the fabrication of silicon nitride ($\mathrm{Si_3N_4}$) waveguides with unprecedentedly smooth sidewalls and tight confinement with record low propagation losses. This is achieved by combining the photonic Damascene process with a novel reflow process, which reduces etching roughness, while sufficiently preserving dimensional accuracy. This leads to previously unattainable \emph{mean} microresonator Q factors larger than $5\times10^6$ for tightly confining waveguides with anomalous dispersion. Via systematic process step variation and two independent characterization techniques we differentiate the scattering and absorption loss contributions, and reveal metal impurity related absorption to be an important loss origin. Although such impurities are known to limit optical fibers, this is the first time they are identified, and play a tangible role, in absorption of integrated microresonators. Taken together, our work provides new insights in the origins of propagation losses in $\mathrm{Si_3N_4}$ waveguides and provides the technological basis for integrated nonlinear photonics in the ultra-high Q regime

Peran Pemerintahan Daerah dalam Pengembangan Desa Tertinggal di Kecamatan Rupat Kabupaten Bengkalis Tahun 2012

This study , entitled The Role of Local Government in Rural Development inSub Rupat Disadvantaged Bengkalis 2012. This research was motivated by Act No. 32of 2004 on regional administration , which in the Act states that the development of theDistrict and City organized with attention to the principles of democracy, communityparticipation, equity and justice as well as attention to the potential diversity regionaldiversity. Law gives full autonomy to the District and the City to establish andimplement policies and initiatives according to the aspirations of its people.Problems contained in this sekripsi is still underdeveloped villages in thedistrict Rupat Bengkalis in 2012. For this study aims to determine how the localgovernment s role in the development of underdeveloped villages, as well as toovercome the obstacles in the development of underdeveloped villages. Those used inthis research method is a method that describes the qualitative descriptive data. Datacollection techniques used are documentation and field study by interviewing while thedata sources used is primary data obtained from the study sites and is supported bysecondary data.Based on the results of research conducted, Bengkalis government has donesome role to promote development that improves the quality of education, economicinfrastructure development, infrastructure development liaison, communityempowerment and improved quality of plantation society, but not optimal in practice,because there are several factors inhibiting such limited sources of funding, poor qualityof human resources, guidance and supervision is lacking and not well targeted aid that isgiven.Keywords: Roles, Policies, Development, Local Government, Rural Disadvantaged

A dynamics-driven approach to precision machines design for micro-manufacturing and its implementation perspectives

Precision machines are essential elements in fabricating high quality micro products or micro features and directly affect the machining accuracy, repeatability and efficiency. There are a number of literatures on the design of industrial machine elements and a couple of precision machines commercially available. However, few researchers have systematically addressed the design of precision machines from the dynamics point of view. In this paper, the design issues of precision machines are presented with particular emphasis on the dynamics aspects as the major factors affecting the performance of the precision machines and machining processes. This paper begins with a brief review of the design principles of precision machines with emphasis on machining dynamics. Then design processes of precision machines are discussed, and followed by a practical modelling and simulation approaches. Two case studies are provided including the design and analysis of a fast tool servo system and a 5-axis bench-top micro-milling machine respectively. The design and analysis used in the two case studies are formulated based on the design methodology and guidelines

An Efficient Microcontroller Based Sun Tracker Control for Solar Cell Systems

The solar energy is fast becoming a different means of electricity resource. Now in world Fossil fuels are seriously depleting thus the need for another energy source is a necessity. To create effective utilization of its solar, energy efficiency must be maximized. An attainable way to deal with amplifying the power output of sun-powered exhibit is by sun tracking. This paper presents the control system for a solar cell orientation device which follows the sun in real time during daytime

Vacuum ultraviolet photoabsorption spectra of nitrile ices for their identification on Pluto

Icy bodies, such as Pluto, are known to harbor simple and complex molecules. The recent New Horizons flyby of Pluto has revealed a complex surface composed of bright and dark ice surfaces, indicating a rich chemistry based on nitrogen (N2), methane (CH4), and carbon monoxide (CO). Nitrile (CN) containing molecules such as acetonitrile (CH3CN), propionitrile (CH3CH2CN), butyronitrile (CH3CH2CH2CN), and isobutyronitrile ((CH3)2CHCN) are some of the nitrile molecules that are known to be synthesized by radiative processing of such simple ices. Through the provision of a spectral atlas for such compounds we propose that such nitriles may be identified from the ALICE payload on board New Horizons</i

AUTO-CDD: automatic cleaning dirty data using machine learning techniques

Cleaning the dirty data has become very critical significance for many years, especially in medical sectors. This is the reason behind widening research in this sector. To initiate the research, a comparison between currently used functions of handling missing values and Auto-CDD is presented. The developed system will guarantee to overcome processing unwanted outcomes in data Analytical process; second, it will improve overall data processing. Our motivation is to create an intelligent tool that will automatically predict the missing data. Starting with feature selection using Random Forest Gini Index values. Then by using three Machine Learning Paradigm trained model was developed and evaluated by two datasets from UCI (i.e. Diabetics and Student Performance). Evaluated outcomes of accuracy proved Random Forest Classifier and Logistic Regression gives constant accuracy at around 90%. Finally, it concludes that this process will help to get clean data for further analytical process

Considering the impact of situation-specific motivations and constraints in the design of naturally ventilated and hybrid buildings

A simple logical model of the interaction between a building and its occupants is presented based on the principle that if free to do so, people will adjust their posture, clothing or available building controls (windows, blinds, doors, fans, and thermostats) with the aim of achieving or restoring comfort and reducing discomfort. These adjustments are related to building design in two ways: first the freedom to adjust depends on the availability and ease-of-use of control options; second the use of controls affects building comfort and energy performance. Hence it is essential that these interactions are considered in the design process. The model captures occupant use of controls in response to thermal stimuli (too warm, too cold etc.) and non-thermal stimuli (e.g. desire for fresh air). The situation-specific motivations and constraints on control use are represented through trigger temperatures at which control actions occur, motivations are included as negative constraints and incorporated into a single constraint value describing the specifics of each situation. The values of constraints are quantified for a range of existing buildings in Europe and Pakistan. The integration of the model within a design flow is proposed and the impact of different levels of constraints demonstrated. It is proposed that to minimise energy use and maximise comfort in naturally ventilated and hybrid buildings the designer should take the following steps: 1. Provide unconstrained low energy adaptive control options where possible, 2. Avoid problems with indoor air quality which provide motivations for excessive ventilation rates, 3. Incorporate situation-specific adaptive behaviour of occupants in design simulations, 4. Analyse the robustness of designs against variations in patterns of use and climate, and 5. Incorporate appropriate comfort standards into the operational building controls (e.g. BEMS)