Miracle-dz/UniFAR-FTUs huggingface dataset:
Experimental Determination of Friction Factors for Mist and Foam Drilling and Well Cleanout Operations

This work covers both theoretical and experimental analysis of frictional losses due to the presence of solids in vertical flow of solids-foam slurries. RabinowitshMooney generalized flow equations for time-independent fluids from the theoretical basis for the rheological analysis. Experimental work was done with an apparatus designed to simulate actual field conditions as closely as possible. The test section consists of an annulus with 4.0-in. casing and 1.5-in. tubing. The surface active agent used is an aniomic biodegradable foamer (ADOFOAM BF-1) and constitutes 1 percent of the liquid volume. Foam qualities and wall shear rates ranged from 0.64 to 0.99, and 100 to 1000 sec/sup -1/, respectively. Semi-empirical equations for predicting friction factors due to solids are presented. Sandstone and limestone particles were used. Average particle size ranged from 0.025 to 0.11 in. and a total of 337 data points were used in the correlations. Data collection was carried out above solid saltation velocities under fully developed steady-state flow conditions. Results show that the friction factor of suspension can be treated as the sum of the friction factor due to the fluid and that due to the solids. For a constant foam Reynold's number, the frictional losses due to the presencemore » of solids increase as the solids mass flow rate (or solids content) increases. Solids friction factor was found to increase with increasing particles Froude number (gd /SUB s/ /V/sup 2/ /SUB F/ ), density ratio (p /SUB s/ /p /SUB F/ ), solids concentration, but decreases with increasing fluid Reynolds' number. « less
Risk analysis of intelligent transportation system investments

Improvements to urban transportation in terms of user service, environmental effects and cost efficiency can be achieved through careful planning and application of intelligent transportation systems (ITS). Since public and/or public-private joint venture funds are used as investments in these systems and the results cannot be predicted with certainty, it is prudent to subject such investments to risk analysis. This study reports a methodological framework for the risk analysis of ITS applications in urban transportation with focus on public transit. The role of advanced technology in shaping public transit systems at the strategic, tactical and operational levels is acknowledged. Evaluation and capital budgeting methodological improvements, particularly risk analysis, are described for ITS capital investment socio-economic analysis. Bayesian and Monte Carlo simulation approaches are illustrated for assessing risk in ITS investments, including feasibility of additional information acquisition in order to enhance knowledge of uncertain factors.
Tunable antenna techniques for compact handset applications

Today's handset antenna needs to support many more bands complying with the standards specifications, yet still within the handset confined form factor. This study presents novel tunable antennas techniques. The antenna tuning here is achieved by loading the antenna aperture. Different loading types, topologies and placement options for optimised performance are investigated leading to design recommendations and guidelines. These are used in the successful design of two planar inverted-F antenna-based handset antennas with a low band tuning range of 620–950 MHz and a high band tuning range of 1.5–2.1 GHz. The designed tunable antennas are miniaturised in the process while maintaining very good radiation performance.
Position Sensorless Control of PMSG in Wind Energy Conversion System

This paper presents a position sensorless operating method in WECS (Wind Energy Conversion System) based on PMSG (Permanent Magnet Synchronous Generator). A position sensorless operating method for direct-drive PMSG using sliding mode observer is proposed. With this method, position angles can be estimated only by measuring phase voltages and currents. By analyzing the cause of angle error, which increases when the PMSG is operating at high speed, a new dynamic angular compensation solution is developed. This method proves to be effective and necessary by experiments based on simulink.
African American Women's Dress in Georgia, 1890-1914 A Photographic Examination

This study examines the types of clothing worn by African American women living in the state of Georgia between 1890 and 1914. The researchers used historical photographs as primary sources to document clothing. The photographs are located in three collections: Spelman College, Atlanta University, and the Georgia Department of Archives and History. The clothing in each photograph was recorded and compared to styles of clothing advertised in national magazines of the period corresponding to the date of the photograph. Analysis revealed that (a) African American women in Georgia in the late nineteenth and early twentieth centuries wore clothing similar in style to fashions advertised and illustrated in magazines and newspapers of the period, and (b) some items of dress were distinctive, that is, not illustrated in national periodicals of the time.
Business ethics in tourism – As a dimension of TQM

The aim of the paper is to emphasise ethics as a dimension of TQM, as well as a dimension of the quality of a community and the quality of life and work. This paper focuses on business ethics and the social responsibility of business enterprises and tourism. After providing the definitions of ethics, business ethics and the social responsibility of business, the paper gives an example of ethics and social responsibility in the tourism and hotel industry, which is one of the world's greatest industries and also a social phenomenon with a great tendency to expand and develop further. The ethical components of the tourism and hotel industry are important due to the industry's great international importance. The main goal of managers is to generate profits, but only within the legal framework and bearing in mind the rule: ‘Never cheat the customer. ’ Business ethics prescribes profit making, but with respect for ethical principles and standards. Business ethics increases the reputation and market competitiveness of an enterprise. Croatia wants to join the European Union. The prerequisite is to meet European standards in all fields of work and life and all social areas. Among those standards are also business standards and business ethics. One of the weaknesses of Croatian economy and society is a high corruption index. The aim of this paper is to prove the importance of business ethics in tourism in helping Croatia approximate EU standards.
Techno-economic analysis of photovoltaic pumping system for rural water supply in Ethiopia

The diesel-driven water pumping systems have a great impact on rural water supply in Ethiopia in past decades due to the lack of access to grid electricity and associated capital intensive nature of grid expansion to rural areas. However, the requirement of diesel generator for frequent maintenance and soaring fuel cost encourages the government and concerned bodies such as NGO to go for most reliable and cost-effective alternatives. In this paper, direct coupled photovoltaic (PV) pumping system has been designed for hypothetical rural village in southern region near Arba Minch (latitude 6.02″N, Longitude 37.54″E) to show techno-economic feasibility of the technology. The result shows that direct coupled PV pumping system is cost-effective in terms of life cycle cost and technologically feasible for rural water supply by virtue of its very low running cost and high reliability of the component and the system as a whole.
Dealing with Observation Outages within Navigation Data using Gaussian Process Regression

Gaussian process regression (GPR) is used in a Spare-grid Quadrature Kalman filter (SGQKF) for Strap-down Inertial Navigation System (SINS)/odometer integrated navigation to bridge uncertain observation outages and maintain an estimate of the evolving SINS biases. The SGQKF uses nonlinearized dynamic models with complex stochastic nonlinearities so the performance degrades significantly during observation outages owing to the uncertainties and noise. The GPR calculates the residual output after factoring in the contributions of the parametric model that is used as a nonlinear SINS error predictor integrated into the SGQKF. The sensor measurements and SINS output deviations from the odometer are collected in a data set during observation availability. The GPR is then applied to predict SINS deviations from the odometer and then the predicted SINS deviations are fed to the SGQKF as an actual update to estimate all SINS biases during observation outages. We demonstrate our method's effectiveness in bridging uncertain observation outages in simulations and in real road tests. The results agree with the theoretical analysis, which demonstrate that SGQKF using GPR can maintain an estimate of the evolving SINS biases during signal outages.
Island Hole Automatic Filling Algorithm in Triangular Meshes

Aiming at the triangular mesh holes generated from incomplete data in reverse engineering, a novel algorithm on island filling was proposed. The focal point of this work was automatic recognition and repairing algorithm on island holes. The island holes are recognized based on the projection on characteristic plan. Then, by connecting island holes and outside holes of the island, island holes are converted into the ordinary holes to repair. Experiment result shown that the proposed method is efficient and stable in island hole filling.
Stresses in Proton Exchange Membranes Due to Hydration-Dehydration Cycles

Durability of the proton exchange membranes (PEM) is a major technical barrier to the economic viability of stationary and transportation applications of PEM fuel cells. In order to reach Department of Energy objectives for automotive PEM fuel cells, a design lifetime of 5,000 hours over a wide temperature range is required. Reaching these lifetimes is an extremely challenging technical problem. Though good progress has been made in recent years, there are still issues that need to be addressed to assure successful, economically viable, long-term operation of PEM fuel cells. The lifetime is limited due to gradual degradation of both the electro-chemical and hygro-thermo-mechanical properties of the membranes. Eventually the system fails due to a critical reduction of the voltage or mechanical damage. However, the hygro-thermo-mechanical loading of the membranes and how this effects the lifetime of the fuel cell is not understood. The long-term objective of the research is to establish a fundamental understanding of the mechanical processes in degradation and how they influence the lifetime of PEMs. In this paper, we discuss the finite element models developed to investigate the in-situ stresses in polymer membranes.Copyright © 2005 by ASME
Force Analysis and Application of a Three-Point Hitch Dynamometer

DESIGN, construction, calibration and application of calibration equations for a three-point-hitch dynamometer are discussed. The dynamometer utilized a strain gaged steel tube as a sensing element. Vertical and horizontal implement forces could be resolved to 77N (17 lb) with a computer-based instrumentation system. This system produced consistent and useful data in extensive field experiments.
An analytical threshold-voltage model of trench-isolated MOS devices with nonuniformly doped substrates

A simple closed-form expression of the threshold voltage is developed for trench-isolated MOS (TIMOS) devices with feature size down to the deep-submicrometer range. The analytical expression is the first developed to include the nonuniform doping effect of a narrow-gate-width device. The inverse narrow width effect can be predicted analytically from the proposed model. It was derived by modeling the gate sidewall capacitance to include the two-dimensional field-induced edge fringing effect and solving the Poisson equation to include the channel implant effect at different operating backgate biases. A two-dimensional simulation program was developed, and the simulated data were used for verification of the analytical model. Good agreements between the modeled and simulated data have been achieved for a wide range of gate widths and biases. The model is well suited for the design of the basic transistor cell in DRAM circuits using trench field oxide isolation structure. >
Computational Analysis of a High-Lift and Low Reynolds Number Airfoil at Turbulent Atmospheric Conditions

Selection of airfoil is crucial for better aerodynamic performance and design of aerodynamic applications such as wind turbine and aircrafts. In this paper, a high-lift and low-Reynolds number airfoil has been selected and investigated through computational analysis for applying it for small-sized wind turbines as blades. The S1223 airfoil, designed by the University of Illinois at Urbana-Champaign, was chosen for its high-lift characteristics at low Reynolds number typically encountered by the small wind turbines. CFD work is performed with S1223 airfoil profile over a wide range of conditions of interest to analyze the performance of the airfoil using the Spalart-Allmaras turbulence model. The results obtained from the simulation works have been compared with experimental data for validation purpose. It has been found that the Spalart-Allmaras model conforms well with the experimental results, though the values of lift coefficients (Cl) are slightly less than the experimental results. In the present analysis, velocity distributions are analyzed at different angle of attacks for different turbulence intensities. It has been observed that there is vortex shedding around the trailing edge of the airfoil for both turbulence levels. It has been observed in the present study that due to increase in turbulence intensity, both the maximum lift coefficient and the stall angle increases significantly. It has been found after investigating the effect of turbulence intensity over lift-to-drag coefficient ratio that it drastically decreases due to increase in turbulence intensity up to certain value (about 3.5%), then it starts decreasing in gradual manner.Copyright © 2009 by ASME
A framework for simulation-based optimization with application to green building design

This paper presents an object-oriented framework that gives attention to the features of simulation-based optimization problems such as hierarchical variables and the coupling with simulation programs. The framework consists of three basic modules: the variables module, the simulation module, and the optimizer module. The variables module defines variables and organizes them according to their relationships. The simulation module evaluates objective functions and functional constraints. The optimizer module implements optimization algorithms. The genetic algorithms implemented in the optimizer module can solve (1) unconstrained single objective optimization problems, (2) constrained single objective optimization problems, and (3) unconstrained multi-objective optimization problems. The application of this framework is demonstrated through a case study for green building design.
Development of an optical accelerometer for low-frequency vibration using the voice coil on a DVD pickup head

In this paper, an economical and highly sensitive optical accelerometer using a commercial optical pickup head is proposed. In the proposed design, the moving part of a voice coil motor (VCM) built in the DVD pickup head is used as the seismic mass which combines with the optical system of the DVD pickup to form an accelerometer. This system not only reduces the design complexity and the manufacturing process but also obtains good measurement effect. Experimental results have shown that the accelerometer at low frequency has a sensitivity of 24.362 V/g.
Setup for potential bias experiments on the Saha Institute of Nuclear Physics tokamak

An experimental setup for studying the influence of the radial electric field on very low qa plasma on the Saha Institute of Nuclear Physics tokamak is presented. A high current, high voltage pulsed power supply, using a semiconductor controlled rectifier (SCR) as a dc switch is developed and used to bias a tungsten electrode inserted inside the plasma. The electrode’s exposed length and its position inside the plasma are controlled by a double bellows assembly to optimize the electrode-exposed length. We show that using the force commutation method to turn the SCR off to get the power pulse desired has good potential for carrying out similar kinds of studies, especially in a low budget small tokamak.
CLOSED-LOOP SEARCH METHOD FOR ON-LINE AUTOMATIC CALIBRATION OF MULTI-CAMERA INSPECTION SYSTEMS

Consistency is important to on-line machine vision inspection systems. Variations due to large-scale lighting, multiple cameras, environmental conditions, and noises can substantially diminish system accuracy and stability. This article presents a signal transformation and a three-phase optimization method which minimizes such variations in a closed-loop. It provides an effective method for on-line automatic camera calibration (ACC) of large vision systems with multiple lanes and multiple cameras to ensure accurate and consistent inspections. This method is applicable to fruits, vegetables, and other food/non-food materials.
Development and validation of a nomogram for predicting the probability of nontraumatic osteonecrosis of the femoral head

Background Although corticosteroids and alcohol are two major risk factors for nontraumatic osteonecrosis of the femoral head (NONFH), the effects of other factors have rarely been studied, thereby making early diagnosis and treatment of NONFH difficult. This study aimed to develop and validate a nomogram to estimate the probability of NONFH using clinical risk factors other than corticosteroids and alcohol consumption. Methods A training cohort of 790 patients (n=434, NONFH; n=356, femoral neck fractures [non-NONFH]) diagnosed in our hospital from January 2011 to December 2016 was used for model development. A least absolute shrinkage and selection operator (lasso) regression model was used for date dimension reduction and optimal predictor selection. A predictive model was developed from univariate and multivariate logistic regression analyses. Performance characterisation of the resulting nomogram included calibration, discriminatory ability, and clinical usefulness. After internal validation, the nomogram was further evaluated in a separate cohort of 300 consecutive patients included between January 2017 and December 2018. Results The simple prediction nomogram included five predictors from univariate and multivariate analyses, including gender, total cholesterol levels, triglyceride levels, white blood cell count, and platelet count. Internal validation showed that the model had good discrimination (area under the receiver operating characteristic curve [AUC]=0.80) and calibration. Good discrimination (AUC=0.81) and calibration were preserved in the validation cohort. Decision curve analysis showed that the predictive nomogram was clinically useful. Conclusions The simple diagnostic nomogram, which combines demographic data and laboratory blood test results, was able to quantify the probability of NONFH in cases of early screening and diagnosis.
The Application of Self-Organizing Map (SOM) to Assess Power Communication Network Reliability

A novel method was proposed to evaluate the reliability of power communication network based on self-organizing map via analyzing the problems of current power communication network reliability evaluation. This proposed method overcomes not only the influence of subjective factors on the evaluation, but also the problem of weight. Excellent results were obtained by applying the new model to evaluating the ten communication networks. Therefore, it is proven to be objective, reasonable and effective in practice.
A Method for Real-Time Estimating Pose of Large Aircraft Component in Process of Pose Adjustment Based on the Unscented Kalman Filter

To estimate the pose of large aircraft component in pose adjustment quickly and accurately, a real-time estimation method based on Unscented Kalman filter (UKF) is proposed. Firstly, in the process of the aircraft component adjustment, a rough value of aircraft component’s pose is acquired by using forward kinematic model and the displacement of positioners on real time. Then, position of a measuring point fixed on aircraft component is obtained by a laser tracker. At last, UKF is employed to integrate the previous rough value and the measuring point position for evaluating the accurate pose of aircraft component. Numerical simulation results show that the presented method is achieved easily, calculated fast and high accurate.
A visible light photon-counting imaging detector based on induction readout

Photon-counting imaging detectors based on microchannel plate (MCP) and position-sensitive anode are characterized by extremely high sensitivity, as well as the ability to detect single photons. In this study, a visible light photon-counting imaging detector based on induction readout was developed for the detection of weak light intensities, such as photon counting radar and biofluorescence lifetime imaging. The design is based on a 25 mm diameter multi-alkali S20 photocathode followed by a MCP stack, and read out by a high-resistance Ge layer anode. The position-sensitive anode was located at the atmosphere side of the Ge substrate. Such a detector was advantageous in terms of reconfigurability and detachability. The imaging performance of the detector was tested by using the wedge and strip anode to decode the photon event position information. The experimental results showed a detector gain reaching about 3×106 , pulse height resolution (PHR) of about 105%, and spatial resolution better than 100μm.
Integration of monopole slot and monopole strip for internal WWAN handset antenna

A novel internal handset antenna formed by a monopole slot and a monopole strip for the wireless wide area network (WWAN) operation in the 824–960 and 1710–2170 MHz bands is presented. The monopole strip is disposed in the monopole slot, and both are embedded in the system ground plane of the handset with a small board space of 9 × 40 mm2 at about the bottom edge of the circuit board. The monopole strip serves as a feed for the monopole slot and also functions as an efficient radiator. In the proposed design, the monopole slot generates a quarter‐wavelength slot mode in the antenna's lower band, while the monopole strip contributes its quarter‐wavelength mode in the antenna's upper band. By including a vertical strip that can be enclosed inside the handset casing or be a part of the bezel surrounding, the periphery of the handset casing and connected to the bottom edge of the system ground plane, the impedance matching of the excited slot mode can be greatly improved. In this case, the proposed antenna can provide two wide operating bands with good impedance matching to cover the pentaband WWAN operation. Detailed operating principle of the integrated monopole slot and monopole strip for the internal WWAN handset antenna is described. The proposed antenna is also fabricated and obtained results are presented and discussed. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1718–1723, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26870
InP-InGaAs uni-travelling-carrier photodiode for monolithic integration with heterojunction bipolar transistors

A common epitaxial layer structure is proposed for a uni-travelling-carrier photodiode and a heterojunction bipolar transistor (HBT) for which zinc indiffusion is used on the HBT base-collector junctions to complete the photodiode structure. Fabricated photodiodes show 3 dB bandwidths of between 60 and 80 GHz for output voltages between 1 and 2 V.