A Sparse Stress Model

Force-directed layout methods constitute the most common approach to draw general graphs. Among them, stress minimization produces layouts of comparatively high quality but also imposes comparatively high computational demands. We propose a speed-up method based on the aggregation of terms in the objective function. It is akin to aggregate repulsion from far-away nodes during spring embedding but transfers the idea from the layout space into a preprocessing phase. An initial experimental study informs a method to select representatives, and subsequent more extensive experiments indicate that our method yields better approximations of minimum-stress layouts in less time than related methods.Comment: Appears in the Proceedings of the 24th International Symposium on Graph Drawing and Network Visualization (GD 2016

Feasibility Study of Solar Powered Unmanned Aerial Vehicle

High Altitude Long Endurance Unmanned Aerial Vehicles (HALE UAVs) could provide an improved service and/or flexibility at a reduced cost over existing systems for a vast number of civil patrol and surveillance applications. This document looks into the Feasibility and Conceptual Design of Solar Powered UAV for HALE applications. It mentions the advancements in technology of the components required to build an efficient solar powered UAV. It also provides a preliminary design methodology that can be adopted for the conceptual design of Solar Powered UAV. It also emphasizes the Aerodynamic difficulties that are faced in HALE configurations

Grain Configuration of Solid Rocket Motor

The solid rocket motor upper stage for a space launch vehicle is a more efficient propulsion technology than the liquid rocket motor upper stage. Its grain design has the potential to be crucial in terms of lowering inert mass by adopting improved volume efficiency with the lowest practicable sliver size while keeping maximum strength. Specifically, the strategy for (3D) grain arrangement of the slot for the upper stage solid rocket engine has been described in this paper. The complex configuration is established by the design process, which takes place under a parametric model of geometry in (CAD) software and is typified by varied dynamics. When constructing solid propellant rocket motors, grain arrangement is a vital and critical step. Accurate estimates of grain geometric properties play a key role in performance prediction and can be a vital and critical stage in the design of solid propellant rocket motors. This research study proposes an effective performance-matching design framework for solid rocket motors that are tuned to suit a range of thrust performance criteria. The framework is constructed utilising an innovative and specialised general design technique that was designed to evaluate the general design parameters, which is given in this study. Because of the findings obtained, it can be stated that the recommended framework is a practical and efficient approach for solid rocket engine design and development

Investigation of Canard Missile with Planar and Grid Fins by using CFD Tool

The aerodynamic coefficients and flow surrounding a canard missile design were predicted using viscous computational fluid dynamics simulation. The computations were performed at speeds between 1.5 and 3.0. High-speed flight is possible with canard deflection angles of 0 to 10 degrees, as well as planar and grid tail fins. The estimated aerodynamic coefficients were found to be astonishingly close to those obtained in the wind tunnel once data from the wind tunnel was analysed. It is possible that the flow visualisations produced by this work could lead to a better understanding of flow physics and the development of superior canard and tail fin designs for missiles and rockets among other things. Planar fins have a negative roll impact because of the pressure difference between the lowered fin and the canard trailing vortices. Grid tail fins improved the canards\u27 ability to roll at low supersonic speeds by increasing their rolling efficiency

Comparison of the extraction efficiencies of four different solvents used in trace metal digestion of selected soils within Abakaliki, Nigeria

Soil pollution by trace metals is one of the major global environmental challenges facing us today. Extraction methods are key to predicting plant uptake of trace metals from soil. This work seeks to compare the extraction efficiencies of EDTA, DTPA, HNO3/HClO4 and HCl/HNO3 used in the digestion of soil samples collected from 11 different locations (7 farmlands, 2 waste dumpsites and 2 sections of a mechanic workshop) within Abakaliki metropolis, between August and September 2007. Concentrations of 7 selected trace metals (Pb, Zn, Mn, Ni, Cd, Cu and Fe) were determined in the digested soil samples using atomic absorption  spectrophotometer. The concentrations (mg/kg) range, irrespective of sampling sites were: Pb (2.85-43.07; 1.42-11.49; 3.83-131.90; 1.98-184.12), Zn (0.02-3.98; 0.01-0.79; 2.25-13.22; 0.15-39.45), Mn (1.33-78.83; 0.38-14.85; 1.02-66.24; 0.84-104.39), Ni (1.15-14.10; 0.07-2.57; 2.09-49.70; 5.10-92.72), Cd (0.03-2.79; 0.01-0.61; 0.25-9.20; 0.15- 3.68), Cu (1.59-79.96; 0.65-14.33; 1.02-184.68; 1.60-134.10), Fe (6.62-149.44; 0.39-12.22; 44.95-375.27; 7.48-548.32) using EDTA, DTPA, HNO3/HClO4 and HCl/HNO3 respectively as extractanes. Results revealed that all extractants showed strong positive correlation in bringing only Cd into solution. ANOVA depicted no significant difference in mean trace metals contents of soils from mechanic workshops as extracted with all solutions, while other locations did. For risk assessment, only Cd, Ni and Pb had their values within the regulatory limits, whereas others were above the limits in all samples from different locations

Engine Use In Hybrid Rocket - A Review

Despite all the other rocket motors on the market such as solid and liquid. A historically failed motor was in the market which was handicapped in performance but now with technological development in the previous years, hybrid rocket motor is the most influential talk in the market. Deeper in the paper we will discuss the hybrid motor focusing on the fuel used in Hybrid rocket engines and the performance depending on the design. Furthermore, this review paper will help us to study the different materials for the betterment of the engine performance. We will also be focusing on the methods required to improve total impulse. Moreover, will be elaborating on the performance of paraffin wax and its material property

Conceptual design of Blended Wing Body for Future Air Transportation

Blended wing body is a fixed wing aircraft which are smoothly blended together with no clear dividing line and no distinct wings also be given a wide Aerofoil shaped body. The future transportation is of aircrafts will incline towards the aerodynamically efficient and capable of carrying large number of passengers over long range and environmental benefits is the main paradigm in the design of aircraft BWB has a high lift to drag ratio which increases the CL max and velocity of the airplane with high load factor and high economy compared with traditional aircraft. Evacuation pressure or the cabin pressurization is the major issues in most of the designs with the minimum aerodynamic lift coefficient and drag coefficient. On the other side of the trend is towards the increasing cruise speed. High speed flow is connected with overcoming of intensive drag rise accruing due to existence of intensive shock, closing local area of supersonic flow. Increase of flight Mach number is possible only by using flow control methods and through affecting the shock increases of aspect ratio leads to increase of lift coefficient corresponding to maximal lift to drag. High bypass ratio engines have smaller fuel consumption and lower noise level but have negative effect on flow around airframe including take-off and landing phases. The necessity of solving problem of intensive aerodynamic heating of surface element of flight vehicles and by ensuring of their stability and controllability and also by need of implementing of high-volume tanks for hydrogen fuel and super high bypass ratio engines

Integrating Remote Sensing Data into Fuzzy Control System for Variable Rate Irrigation Estimates

Variable rate irrigation (VRI) is the capacity to vary the depth of water application in a field spatially. Developing precise management zones is necessary to efficient variable rate irrigation technologies. Intelligent fuzzy inference system based on precision irrigation knowledge, i.e., a system capable of creating prescriptive maps to control the rotation speed of the central pivot. Based on the VRI-prescribed map created by the intelligent system of decision-making, the pivot can increase or decrease its speed, reaching the desired depth of application in a certain irrigation zone. Therefore, this strategy of speed control is more realistic compared to traditional methods. Results indicate that data from the edaphoclimatic variables, when well fitted to the fuzzy logic, can solve uncertainties and non-linearities of an irrigation system and establish a control model for high-precision irrigation. Because remote sensing provides quick measurements and easy access to crop information for large irrigation areas, images will be used as inputs. The developed fuzzy system for pivot control is original and innovative. Furthermore, the artificial intelligent systems can be applied widely in agricultural areas, so the results were favorable to the continuity of studies on precision irrigation and application of the fuzzy logic in precision agriculture

Audition in vampire bats, Desmodus rotundus

1. Within the tonotopic organization of the inferior colliculus two frequency ranges are well represented: a frequency range within that of the echolocation signals from 50 to 100 kHz, and a frequency band below that of the echolocation sounds, from 10 to 35 kHz. The frequency range between these two bands, from about 40 to 50 kHz is distinctly underrepresented (Fig. 3B). 2. Units with BFs in the lower frequency range (10–25 kHz) were most sensitive with thresholds of -5 to -11 dB SPL, and units with BFs within the frequency range of the echolocation signals had minimal thresholds around 0 dB SPL (Fig. 1). 3. In the medial part of the rostral inferior colliculus units were encountered which preferentially or exclusively responded to noise stimuli. — Seven neurons were found which were only excited by human breathing noises and not by pure tones, frequency modulated signals or various noise bands. These neurons were considered as a subspeciality of the larger sample of noise-sensitive neurons. — The maximal auditory sensitivity in the frequency range below that of echolocation, and the conspicuous existence of noise and breathing-noise sensitive units in the inferior colliculus are discussed in context with the foraging behavior of vampire bats

Hubungan antara Kadar Creatine Kinase-MB dengan Mortalitas Pasien Infark Miokard Akut Selama Perawatan di RS. Dr. Wahidin Sudirohusodo, Makasar

Increase of CK-MB level is associated with myocardial infarction size and severity. The aim of this study is to evaluate the correlation between the admission CK-MB level of acute myocardial patients and the in-hospital mortality. Secondary data of 60 acute myocardial infarction patientshospitalized in Intensive Cardiac Care Unit of Dr.Wahidin Sudirohusodo Hospital Makassar from June 2010 to July 2011 were taken. Admission CK-MB levels between the period of 3 hours to 1 week after onset were then analyzed. The mean of admission CK-MB level in the in-hospital survived and non survived acute myocardial infarction patients were 89.52+121.59 U/l and 202.88+192.75 U/l respectively (Mann Whitney Test, p=0.005). There were significant mortality rate difference amongall CK-MB quartiles with mortality rate 13.3%, 6.7%, 40% and 46.7 % in 1st, 2nd, 3rd, and 4th quartile respectively (Chi Square Test, p=0.031) but the odds ratio of mortality between quartiles were not different.. There was significant difference of admission CK-MB levels in the in-hospitalsurvived and non survived acute myocardial infarction.Keywords : CK-MB, myocardial infarction, mortalityAbstrakPeningkatan kadar CK-MB pada infark miokard akut menunjukkan luas dan parahnya penyakit. Penelitian ini bertujuan untuk menilai hubungan antara kadar CK-MB pada pasien infark miokard akut saat masuk rumah sakit dan mortalitas pasien selama perawatan di rumah sakit.. Data sekunder diambil dari rekam medis 60 pasien infark miokard akut yang dirawat di Unit Perawatan Jantung Intensif Rumah Sakit Dr. Wahidin Sudirohusodo, Makassar periode Juli 2010 hingga Juni 2011. Kadar CK-MB diperoleh saat masuk rumah sakit antara 3 jam hingga 1 minggu setelah onset. Rerata kadar CK-MB pada penderita infark miokard akut yang survive dan meninggal selama perawatan adalah 89,52+121,59 U/l dan 202,88+192,75U/l (Uji Mann Whitney, p=0,005). Ditemukan perbedaantingkat mortalitas yang bermakna antar kuartil CK-MB masing-masing 13,3%, 6,7%, 40% dan 46,7% pada kuartil 1, 2, 3 dan 4 berturut-turut ( Uji Chi Square, p=0,031) tetapi risiko mortalitas antar kuartil tidak berbeda bermakna. Ditemukan perbedaan bermakna kadar CK-MB pada pasien yang survive maupun yang meninggal selama perawatan.Kata kunci : CK-MB, infark miokard, mortalita