WorldWideScience

Sample records for fracture control design

  1. Design and real-time control of a robotic system for fracture manipulation.

    Science.gov (United States)

    Dagnino, G; Georgilas, I; Tarassoli, P; Atkins, R; Dogramadzi, S

    2015-08-01

    This paper presents the design, development and control of a new robotic system for fracture manipulation. The objective is to improve the precision, ergonomics and safety of the traditional surgical procedure to treat joint fractures. The achievements toward this direction are here reported and include the design, the real-time control architecture and the evaluation of a new robotic manipulator system. The robotic manipulator is a 6-DOF parallel robot with the struts developed as linear actuators. The control architecture is also described here. The high-level controller implements a host-target structure composed by a host computer (PC), a real-time controller, and an FPGA. A graphical user interface was designed allowing the surgeon to comfortably automate and monitor the robotic system. The real-time controller guarantees the determinism of the control algorithms adding an extra level of safety for the robotic automation. The system's positioning accuracy and repeatability have been demonstrated showing a maximum positioning RMSE of 1.18 ± 1.14mm (translations) and 1.85 ± 1.54° (rotations).

  2. Fracture design modelling

    Energy Technology Data Exchange (ETDEWEB)

    Crichlow, H.B.; Crichlow, H.B. (ed.)

    1980-02-07

    A design tool is discussed whereby the various components that enter the design process of a hydraulic fracturing job are combined to provide a realistic appraisal of a stimulation job in the field. An interactive computer model is used to solve the problem numerically to obtain the effects of various parameters on the overall behavior of the system.

  3. Fracture mechanics in pavement design

    CSIR Research Space (South Africa)

    Denneman, E

    2009-07-01

    Full Text Available effects. Examples of the use of fracture mechanics providing an alternative to these conventional design parameters are given in the paper. The paper shows that although much further development is required before fracture mechanics can be relied upon...

  4. Clinical effects of internal fixation for ulnar styloid fractures associated with distal radius fractures: A matched case-control study.

    Science.gov (United States)

    Sawada, Hideyoshi; Shinohara, Takaaki; Natsume, Tadahiro; Hirata, Hitoshi

    2016-11-01

    Ulnar styloid fractures are often associated with distal radius fractures. However, controversy exists regarding whether to treat ulnar styloid fractures. This study aimed to evaluate clinical effects of internal fixation for ulnar styloid fractures after distal radius fractures were treated with the volar locking plate system. We used prospectively collected data of distal radius fractures. 111 patients were enrolled in this study. A matched case-control study design was used. We selected patients who underwent fixation for ulnar styloid fractures (case group). Three control patients for each patient of the case group were matched on the basis of age, sex, and fracture type of distal radius fractures from among patients who did not undergo fixation for ulnar styloid fractures (control group). The case group included 16 patients (7 men, 9 women; mean age: 52.6 years; classification of ulnar styloid fractures: center, 3; base, 11; and proximal, 2). The control group included 48 patients (15 men, 33 women; mean age: 61.1 years; classification of ulnar styloid fractures: center, 10; base, 31; and proximal, 7). For radiographic examination, the volar tilt angle, radial inclination angle, and ulnar variance length were measured, and the union of ulnar styloid fractures was judged. For clinical examination, the range of motions, grip strength, Hand20 score, and Numeric Rating Scale score were evaluated. There was little correction loss for each radiological parameter of fracture reduction, and these parameters were not significantly different between the groups. The bone-healing rate of ulnar styloid fractures was significantly higher in the case group than in the control group, but the clinical results were not significantly different. We revealed that there was no need to fix ulnar styloid fractures when distal radius fractures were treated via open reduction and internal fixation with a volar locking plate system. Copyright © 2016 The Japanese Orthopaedic Association

  5. Design and modeling of small scale multiple fracturing experiments

    Energy Technology Data Exchange (ETDEWEB)

    Cuderman, J F

    1981-12-01

    Recent experiments at the Nevada Test Site (NTS) have demonstrated the existence of three distinct fracture regimes. Depending on the pressure rise time in a borehole, one can obtain hydraulic, multiple, or explosive fracturing behavior. The use of propellants rather than explosives in tamped boreholes permits tailoring of the pressure risetime over a wide range since propellants having a wide range of burn rates are available. This technique of using the combustion gases from a full bore propellant charge to produce controlled borehole pressurization is termed High Energy Gas Fracturing (HEGF). Several series of HEGF, in 0.15 m and 0.2 m diameter boreholes at 12 m depths, have been completed in a tunnel complex at NTS where mineback permitted direct observation of fracturing obtained. Because such large experiments are costly and time consuming, smaller scale experiments are desirable, provided results from small experiments can be used to predict fracture behavior in larger boreholes. In order to design small scale gas fracture experiments, the available data from previous HEGF experiments were carefully reviewed, analytical elastic wave modeling was initiated, and semi-empirical modeling was conducted which combined predictions for statically pressurized boreholes with experimental data. The results of these efforts include (1) the definition of what constitutes small scale experiments for emplacement in a tunnel complex at the Nevada Test Site, (2) prediction of average crack radius, in ash fall tuff, as a function of borehole size and energy input per unit length, (3) definition of multiple-hydraulic and multiple-explosive fracture boundaries as a function of boreholes size and surface wave velocity, (4) semi-empirical criteria for estimating stress and acceleration, and (5) a proposal that multiple fracture orientations may be governed by in situ stresses.

  6. Effectiveness of Oral Nutritional Supplementation for Older Women after a Fracture: Rationale, Design and Study of the Feasibility of a Randomized Controlled Study

    Directory of Open Access Journals (Sweden)

    Lockwood Keri A

    2011-06-01

    Full Text Available Abstract Background Malnutrition is a problem for many older people recovering from a hip and other major fractures. Oral supplementation with high calorie high protein nutrients is a simple intervention that may help older people with fractures to improve their recovery in terms of rehabilitation time, length of hospital stay and mortality. This paper reports a pilot study to test the feasibility of a trial initiated in a hospital setting with an oral supplement to older people with recent fractures. Method A randomized controlled trial with 44 undernourished participants admitted to a hospital following a fracture. The intervention group (n = 23 received a high calorie high protein supplement for forty days in addition to their diet of choice. The control group (n = 21 received high protein milk during their hospital stay in addition to their diet of choice and their usual diet when discharged from hospital. Results All participants were women and their mean age was 85.3 (± 6.1 years. Twenty nine (65% participants had a hip fracture. At baseline no differences were measured between the two groups regarding their nutritional status, their cognitive ability or their abilities in activities of daily living. There were no significant differences between the intervention and control group with reference to nutritional or functional parameters at 40 day and 4 month follow-ups. Median length of stay in hospital was 18.0 days, with 12 participants being readmitted for a median of 7.0 days. Conclusion It is feasible to perform a randomised trial in a hospital and community setting to test the effect of an oral high energy high protein supplement for older people. Due to the limited number of participants and incomplete adherence with use of the supplements no conclusion can be drawn about the efficacy or effectiveness of this intervention.

  7. A Thermoelastic Hydraulic Fracture Design Tool for Geothermal Reservoir Development

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad Ghassemi

    2003-06-30

    Geothermal energy is recovered by circulating water through heat exchange areas within a hot rock mass. Geothermal reservoir rock masses generally consist of igneous and metamorphic rocks that have low matrix permeability. Therefore, cracks and fractures play a significant role in extraction of geothermal energy by providing the major pathways for fluid flow and heat exchange. Thus, knowledge of conditions leading to formation of fractures and fracture networks is of paramount importance. Furthermore, in the absence of natural fractures or adequate connectivity, artificial fracture are created in the reservoir using hydraulic fracturing. At times, the practice aims to create a number of parallel fractures connecting a pair of wells. Multiple fractures are preferred because of the large size necessary when using only a single fracture. Although the basic idea is rather simple, hydraulic fracturing is a complex process involving interactions of high pressure fluid injections with a stressed hot rock mass, mechanical interaction of induced fractures with existing natural fractures, and the spatial and temporal variations of in-situ stress. As a result it is necessary to develop tools that can be used to study these interactions as an integral part of a comprehensive approach to geothermal reservoir development, particularly enhanced geothermal systems. In response to this need we have set out to develop advanced thermo-mechanical models for design of artificial fractures and rock fracture research in geothermal reservoirs. These models consider the significant hydraulic and thermo-mechanical processes and their interaction with the in-situ stress state. Wellbore failure and fracture initiation is studied using a model that fully couples poro-mechanical and thermo-mechanical effects. The fracture propagation model is based on a complex variable and regular displacement discontinuity formulations. In the complex variable approach the displacement discontinuities are

  8. The influence of cavity preparation design on fracture strength and mode of fracture of laboratory-processed composite resin restorations.

    Science.gov (United States)

    Fonseca, Rodrigo Borges; Fernandes-Neto, Alfredo Julio; Correr-Sobrinho, Lourenco; Soares, Carlos Jose

    2007-10-01

    Removal of large amounts of sound tooth structure may result in a weakened restored tooth. Nevertheless, removal of tooth structure for cuspal coverage has been recommended to protect teeth restored with laboratory-processed composite resin (LPCR) from fracture. The purpose of this study was to evaluate the influence of different cavity preparation designs on fracture strength and modes of fracture of teeth restored with LPCR. Ninety anatomically similar human third mandibular molars were selected. There were 2 experimental factors, occlusal isthmus width (narrow versus wide) and cuspal coverage (inlay, 1-cusp onlay, 2-cusp onlay, and all-cusp onlay), and 1 control group that received no treatment, resulting in 9 groups (n=10). Indirect composite resin (SR Adoro) restorations were manufactured and adhesively cemented with Adper Single Bond 2 and Rely-X ARC. A compressive loading test (0.5 mm/min) was performed. The modes of fracture were classified according to 4 categories. One-way and 2-way ANOVA followed by Tukey-HSD test were used to statistically analyze the fracture load data (alpha =.05). The statistical analysis failed to show significant differences among restored groups but showed differences between these groups and the control group (P = .001). Two-way ANOVA failed to show any difference when considering the occlusal isthmus width alone (P = .98), cuspal coverage (P = .273), or the interaction between these factors (P = .972). Several teeth had fractures affecting a great amount of both restoration and tooth structure. This in vitro study showed restored teeth having similar fracture strength and fracture modes, suggesting that with the tested preparation designs, there is no advantage of cuspal coverage to protect LPCR restored teeth from fracture.

  9. Rationale and design of the plate or pin (pop study for dislocated midshaft clavicular fractures: study protocol for a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Meylaerts Sven AG

    2011-07-01

    Full Text Available Abstract Background To describe the rationale and design of a future study comparing results of plate fixation and Elastic Stable Intramedullary Nailing (ESIN with a Titanium Elastic Nail (TEN for adults with a dislocated midshaft clavicular fracture. Methods/Design Prospective randomized multicenter clinical trial in two level 1 and one level 2 trauma centers. 120 patients between 18 and 65 years of age will be included. They are randomized to either plate fixation or ESIN with a TEN with a one year follow-up. Sixty patients will be treated with plate fixation and 60 patients will be treated with ESIN. Primary outcome parameter is the Disabilities of the Arm, Shoulder and Hand score after 6 months. Secondary outcome parameters are Constant Shoulder Score, complications, experienced pain, radiologic consolidation and cosmetics after both procedures. Discussion Prospective randomized studies comparing operative techniques for treatment of dislocated midshaft clavicular fracture are lacking. By studying shoulder function, complications, quality of life, radiographic union, cosmetics as well as experienced pain, a complete efficacy assessment of both procedures will be performed. Trial registration The POP study is registered in the Dutch Trial Register (NTR NTR2438.

  10. Guiding-controlling technology of coal seam hydraulic fracturing fractures extension

    Institute of Scientific and Technical Information of China (English)

    Zhai; Cheng; Li; Min; Sun; Chen; Zhang; Jianguo; Yang; Wei; Li; Quangui

    2012-01-01

    Aiming at the uncontrollable problem of extension direction of coal seam hydraulic fracturing,this study analyzed the course of fractures variation around the boreholes in process of hydraulic fracturing,and carried out the numerical simulations to investigate the effect of artificial predetermined fractures on stress distribution around fractured holes.The simulation results show that partial coal mass occurs relatively strong shear failure and forms weak surfaces,and then fractures extended along the desired direction while predetermined fractures changed stress distribution.Directional fracturing makes the fractures link up and the pressure on coal mass is relieved within fractured regions.Combining deep hole controlling blasting with hydraulic fracturing was proposed to realize the extension guiding-controlling technology of coal seam fractures.Industrial experiments prove that this technology can avoid local stress concentration and dramatically widen the pressure relief scope of deep hole controlling blasting.The permeability of fractured coal seam increased significantly,and gas extraction was greatly improved.Besides,regional pressure relief and permeability increase was achieved in this study.

  11. Influence of the preparation design and artificial aging on the fracture resistance of monolithic zirconia crowns

    Science.gov (United States)

    Anastassova-Yoshida, Yana; Nothdurft, Frank Phillip; von See, Constantin; Pospiech, Peter

    2016-01-01

    PURPOSE The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. MATERIALS AND METHODS An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparation design, 30 monolithic zirconia crowns were fabricated. After cementation on Cr-Co alloy dies, the following artificial aging procedures were performed: (1) thermal cycling and mechanical loading (TCML): 5000 cycles of thermal cycling 5℃–55℃ and chewing simulation (1,200,000 cycles, 50 N); (2) Low Temperature Degradation simulation (LTD): autoclave treatment at 137℃, 2 bar for 3 hours and chewing simulation; and (3) no pre-treatment (control group). After artificial aging, the crowns were loaded until fracture. RESULTS The mean values of fracture resistance varied between 3414 N (LTD; 0.8 mm chamfer preparation) and 5712 N (control group; shoulderless preparation). Two-way ANOVA analysis showed a significantly higher fracture loads for the shoulderless preparation, whereas no difference was found between the chamfer preparations. In contrast to TCML, after LTD simulation the fracture strength of monolithic zirconia crowns decreased significantly. CONCLUSION The monolithic crowns tested in this study showed generally high fracture load values. Preparation design and LTD simulation had a significant influence on the fracture strength of monolithic zirconia crowns. PMID:26949485

  12. Fracture control plan for propellant and pressurant tanks

    Science.gov (United States)

    1981-01-01

    To assure the functional integrity of the GLL-RPM fuel and pressurized gas tank, all activities during entire lifetime of the tank, from manufacture to the end of the mission, must be monitored. Specifications are given for all procedures which influence the tank structure including design, manufacture, cleaning, test operations, and storage. Tests to be conducted to demonstrate that requirements of the fracture control plan are satisfied include static tests, cyclic load tests, proof tests, He-leak test, and acceptance tests.

  13. Hemiarthroplasty versus angle-stable locking compression plate osteosynthesis in the treatment of three- and four-part fractures of the proximal humerus in the elderly: design of a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Verbeek Paul A

    2012-02-01

    Full Text Available Abstract Background The optimal surgical management of dislocated three- and four-part fractures of the proximal humerus in elderly patients remains unclear. Most used techniques are hemiarthroplasty and angle-stable locking compression plate osteosynthesis. In the current literature there is no evidence available presenting superior results between hemiarthroplasty and angle-stable locking compression plate osteosynthesis in terms of speed of recovery, pain, patient satisfaction, functional outcome, quality of life or complications. Methods/Design A randomized controlled multicenter trial will be conducted. Patients older than 60 years of age with a dislocated three- or four-part fracture of the proximal humerus as diagnosed by X-rays and CT-scans will be included. Exclusion criteria are a fracture older than 14 days, multiple comorbidity, multitrauma, a pathological fracture, previous surgery on the injured shoulder, severely deranged function caused by a previous disease, "head-split" proximal humerus fracture and unwillingness or inability to follow instructions. Participants will be randomized between surgical treatment with hemiarthroplasty and angle-stable locking compression plate osteosynthesis. Measurements will take place preoperatively and 3 months, 6 months, 9 months, 12 months and 24 months postoperatively. Primary outcome measure is speed of recovery of functional capacity of the affected upper limb using the Disabilities of Arm, Shoulder and Hand score (DASH. Secondary outcome measures are pain, patient satisfaction, shoulder function, quality of life, radiological evaluation and complications. Data will be analyzed on an intention-to-treat basis, using univariate and multivariate analyses. Discussion Both hemiarthroplasty and angle-stable locking compression plate osteosynthesis are used in the current treatment of dislocated three-and four-part fractures of the proximal humerus. There is a lack of level-1 studies comparing

  14. Development of fractures in soft rock surrounding a roadway and their control

    Institute of Scientific and Technical Information of China (English)

    Li Xuehua; Yao Qiangling; Man Jiankang; Chen Chaoqun; He Lihui

    2011-01-01

    As the excavation of roadway,new fractures will be formed and the pre-existing fractures extend with the redistribution of stress in surrounding rocks.Eventually,fracture zone and bed separation are formed in rocks because of the developed fractures.Therefore,mastering the fracture evolution of surrounding rocks is very important to maintain the stability of roadway.The surrounding rocks of main haulage roadway in a certain coal mine is so broken and loose that the supporting is very difficult.Based on comprehensive analysis of the engineering geological conditions,a sight instrument was used to observe the fractures of internal surrounding rocks.Four indices,i.e.,the width of fracture zone W,the number of fractures n,the width of fractures d and rock fracture designation RFD,are put forward to evaluate the fracture development.According to the evolution rules of the soft rock roadway from this paper,control principles by stages and by regions are presented through the research.At the same time,the best time of grouting reinforcement is determined on the basis of fracture saturation.Field practice shows that the roadway can satisfy normal production during service periods by suitable first support and grouting reinforcement.

  15. Mechanical stratigraphic controls on natural fracture spacing and penetration

    Science.gov (United States)

    McGinnis, Ronald N.; Ferrill, David A.; Morris, Alan P.; Smart, Kevin J.; Lehrmann, Daniel

    2017-02-01

    Fine-grained low permeability sedimentary rocks, such as shale and mudrock, have drawn attention as unconventional hydrocarbon reservoirs. Fracturing - both natural and induced - is extremely important for increasing permeability in otherwise low-permeability rock. We analyze natural extension fracture networks within a complete measured outcrop section of the Ernst Member of the Boquillas Formation in Big Bend National Park, west Texas. Results of bed-center, dip-parallel scanline surveys demonstrate nearly identical fracture strikes and slight variation in dip between mudrock, chalk, and limestone beds. Fracture spacing tends to increase proportional to bed thickness in limestone and chalk beds; however, dramatic differences in fracture spacing are observed in mudrock. A direct relationship is observed between fracture spacing/thickness ratio and rock competence. Vertical fracture penetrations measured from the middle of chalk and limestone beds generally extend to and often beyond bed boundaries into the vertically adjacent mudrock beds. In contrast, fractures in the mudrock beds rarely penetrate beyond the bed boundaries into the adjacent carbonate beds. Consequently, natural bed-perpendicular fracture connectivity through the mechanically layered sequence generally is poor. Fracture connectivity strongly influences permeability architecture, and fracture prediction should consider thin bed-scale control on fracture heights and the strong lithologic control on fracture spacing.

  16. Rationale and design of the B-PROOF study, a randomized controlled trial on the effect of supplemental intake of vitamin B12 and folic acid on fracture incidence

    Directory of Open Access Journals (Sweden)

    van Wijngaarden Janneke P

    2011-12-01

    Full Text Available Abstract Background Osteoporosis is a major health problem, and the economic burden is expected to rise due to an increase in life expectancy throughout the world. Current observational evidence suggests that an elevated homocysteine concentration and poor vitamin B12 and folate status are associated with an increased fracture risk. As vitamin B12 and folate intake and status play a large role in homocysteine metabolism, it is hypothesized that supplementation with these B-vitamins will reduce fracture incidence in elderly people with an elevated homocysteine concentration. Methods/Design The B-PROOF (B-Vitamins for the PRevention Of Osteoporotic Fractures study is a randomized double-blind placebo-controlled trial. The intervention comprises a period of two years, and includes 2919 subjects, aged 65 years and older, independently living or institutionalized, with an elevated homocysteine concentration (≥ 12 μmol/L. One group receives daily a tablet with 500 μg vitamin B12 and 400 μg folic acid and the other group receives a placebo tablet. In both tablets 15 μg (600 IU vitamin D is included. The primary outcome of the study is osteoporotic fractures. Measurements are performed at baseline and after two years and cover bone health i.e. bone mineral density and bone turnover markers, physical performance and physical activity including falls, nutritional intake and status, cognitive function, depression, genetics and quality of life. This large multi-center project is carried out by a consortium from the Erasmus MC (Rotterdam, the Netherlands, VUmc (Amsterdam, the Netherlands and Wageningen University, (Wageningen, the Netherlands, the latter acting as coordinator. Discussion To our best knowledge, the B-PROOF study is the first intervention study in which the effect of vitamin B12 and folic acid supplementation on osteoporotic fractures is studied in a general elderly population. We expect the first longitudinal results of the B

  17. Design of Fuzzy Controllers

    DEFF Research Database (Denmark)

    Jantzen, Jan

    1998-01-01

    Design of a fuzzy controller requires more design decisions than usual, for example regarding rule base, inference engine, defuzzification, and data pre- and post processing. This tutorial paper identifies and describes the design choices related to single-loop fuzzy control, based...... on an international standard which is underway. The paper contains also a design approach, which uses a PID controller as a starting point. A design engineer can view the paper as an introduction to fuzzy controller design....

  18. Controlled Source Electromagnetic Monitoring of Hydraulic Fracturing

    Science.gov (United States)

    Couchman, M. J.; Everett, M. E.

    2016-12-01

    Controlled Source Electromagnetics (CSEM) have been used as a direct hydrocarbon indicator since the 1960s, with a resurgence in marine conventional settings in the new millennium, with many studies revolving around detecting a thin resistive layer such as a reservoir at 1m-3km depth. The presence of the resistive layer is characterized by a jump in electric field amplitude recorded at the boundary between the layer and the host sediments. Here the lessons learned from these studies are applied to terrestrial unconventional settings. However, unlike in marine settings where resistive hydrocarbon-charged fluids comprise a conventional reservoir, on land we are interested in electrically conductive injected fluids. The work shown here is a means to develop further methods to enable more reliable terrestrial CSEM monitoring of the flow of injected fluids associated with hydraulic fracturing of unconventional reservoirs and to detect subsurface fluids based on their CSEM signature and in turn, to infer the subsurface flow of electrically conductive injected fluids. Overall this project attempts to create more efficient fracturing, by determining fluid pathways, hence making projects more cost effective by reducing the cost of extraction. The predictive model developed focuses on the mapping of fluid flow in from a horizontal pipe in a uniform halfspace using a long in-line Horizontal Electric Dipole (HED) with electric field amplitude recorded by an array of electric field sensors. The code provided has been edited to include a long-dipole source in addition to the half dipole source originally in place in order to align with current CSEM field practices. The well casing has also been included due to its large effect on CSEM response.

  19. Multiphase control volume finite element simulations of fractured reservoirs

    Science.gov (United States)

    Fu, Yao

    With rapid evolution of hardware and software techniques in energy sector, reservoir simulation has become a powerful tool for field development planning and reservoir management. Many of the widely used commercial simulators were originally designed for structured grids and implemented with finite difference method (FDM). In recent years, technical advances in griding, fluid modeling, linear solver, reservoir and geological modeling, etc. have created new opportunities. At the same time, new reservoir simulation technology is required for solving large-scale heterogeneous problems. A three-dimensional, three-phase black-oil reservoir simulator has been developed using the control volume finite element (CVFE) formulation. Flux-based upstream weighting is employed to ensure flux continuity. The CVFE method is embedded in a fully-implicit formulation. State-of-the-art parallel, linear solvers are used. The implementation takes the advantages of object-oriented programming capabilities of C++ to provide maximum reuse and extensibility for future students. The results from the simulator have excellent agreement with those from commercial simulators. The convergence properties of the new simulator are verified using the method of manufactured solutions. The pressure and saturation solutions are verified to be first-order convergent as expected. The efficiency of the simulators and their capability to handle real large-scale field models are improved by implementing the models in parallel. Another aspect of the work dealt with multiphase flow of fractured reservoirs was performed. The discrete-fracture model is implemented in the simulator. Fractures and faults are represented by lines and planes in two- and three-dimensional spaces, respectively. The difficult task of generating an unstructured mesh for complex domains with fractures and faults is accomplished in this study. Applications of this model for two-phase and three-phase simulations in a variety of fractured

  20. Effects of simplifying fracture network representation on inert chemical migration in fracture-controlled aquifers

    Science.gov (United States)

    Wellman, T.P.; Shapiro, A.M.; Hill, M.C.

    2009-01-01

    While it is widely recognized that highly permeable 'large-scale' fractures dominate chemical migration in many fractured aquifers, recent studies suggest that the pervasive 'small-scale' fracturing once considered of less significance can be equally important for characterizing the spatial extent and residence time associated with transport processes. A detailed examination of chemical migration through fracture-controlled aquifers is used to advance this conceptual understanding. The influence of fracture structure is evaluated by quantifying the effects to transport caused by a systematic removal of fractures from three-dimensional discrete fracture models whose attributes are derived from geologic and hydrologic conditions at multiple field sites. Results indicate that the effects to transport caused by network simplification are sensitive to the fracture network characteristics, degree of network simplification, and plume travel distance, but primarily in an indirect sense since correlation to individual attributes is limited. Transport processes can be 'enhanced' or 'restricted' from network simplification meaning that the elimination of fractures may increase or decrease mass migration, mean travel time, dispersion, and tailing of the concentration plume. The results demonstrate why, for instance, chemical migration may not follow the classic advection-dispersion equation where dispersion approximates the effect of the ignored geologic structure as a strictly additive process to the mean flow. The analyses further reveal that the prediction error caused by fracture network simplification is reduced by at least 50% using the median estimate from an ensemble of simplified fracture network models, and that the error from network simplification is at least 70% less than the stochastic variability from multiple realizations. Copyright 2009 by the American Geophysical Union.

  1. Hydraulic fracture design and optimization of gas storage wells

    Energy Technology Data Exchange (ETDEWEB)

    Mohaghegh, S.; Ameri, S. [Petroleum and Natural Gas and Engineering Department, West Virginia University, P.O. Box 6070, Morgantown, WV (United States); Balanb, B. [Schlumberger Austin Product Center, 8311 North FM 620 Road, Austin, TX (United States); Platon, V. [Baker Atlas, 10201 Westheimer Rd., Houston, TX (United States)

    1999-10-01

    Conventional hydraulic fracture design and optimization involves the use of two- or three-dimensional hydraulic fracture simulators. These simulators need a wealth of reservoir data as input to provide users with usable results. In many cases, such data are not available or very expensive to acquire. This paper provides a new methodology that can be used in cases where detail reservoir data are not available or prohibitively expensive to acquire. Through the use of two virtual intelligence techniques, namely neural networks and genetic algorithms, hydraulic fracture treatments are designed using only the available data. The unique design optimization method presented here is a logical continuation of the study that was presented in two previous papers [McVey et al., 1996, Identification of parameters influencing the response of gas storage wells to hydraulic fracturing with the aid of a neural network, SPE Computer Applications Journal, Apr., 54-57; Mohaghegh et al., 1996b, Predicting well stimulation results in a gas storage field in the absence of reservoir data, using neural networks, SPE Reservoir Engineering Journal, Nov., 54-57]. A quick review of these papers is included here. This method will use the available data on each well, which includes basic well information, production history and results of previous frac job treatments, and provides engineer with a detail optimum hydraulic fracture design unique to each well. The expected post-hydraulic fracture deliverability for the designed treatment is also provided to assist engineers in estimating incremental increase in recovery to be used in economic calculations. There are no simulated data throughout this study and all data used for development and verification of all methods are actual field data.

  2. Control system design guide

    Energy Technology Data Exchange (ETDEWEB)

    Sellers, David; Friedman, Hannah; Haasl, Tudi; Bourassa, Norman; Piette, Mary Ann

    2003-05-01

    The ''Control System Design Guide'' (Design Guide) provides methods and recommendations for the control system design process and control point selection and installation. Control systems are often the most problematic system in a building. A good design process that takes into account maintenance, operation, and commissioning can lead to a smoothly operating and efficient building. To this end, the Design Guide provides a toolbox of templates for improving control system design and specification. HVAC designers are the primary audience for the Design Guide. The control design process it presents will help produce well-designed control systems that achieve efficient and robust operation. The spreadsheet examples for control valve schedules, damper schedules, and points lists can streamline the use of the control system design concepts set forth in the Design Guide by providing convenient starting points from which designers can build. Although each reader brings their own unique questions to the text, the Design Guide contains information that designers, commissioning providers, operators, and owners will find useful.

  3. Discrete Fracture Networks Groundwater Modelling at Bedding Control Fractured Sedimentary Rock mass

    Science.gov (United States)

    Pin, Yeh; Yuan-Chieh, Wu

    2017-04-01

    Groundwater flow modelling in fractured rock mass is an important challenging work in predicting the transport of contamination. So far as we know about the numerical analysis method was consider for crystalline rock, which means discontinuous are treated as stochastic distribution in homogeneous rock mass. Based on the understanding of geology in Taiwan in past few decades, we know that the hydraulic conductivities of Quaternary and Tertiary system rock mass are strongly controlled by development of sedimentary structures (bedding plane). The main purpose of this study is to understand how Discrete Fracture Networks (DFN) affects numerical results in terms of hydraulic behavior using different DFN generation methods. Base on surface geology investigation and core drilling work (3 boreholes with a total length of 120m), small scale fracture properties with in Cho-lan formation (muddy sandstone) are defined, including gently dip of bedding and 2 sub-vertical joint sets. Two FracMan/MAFIC numerical modellings are conducted, using ECPM approach (Equivalent Continuum Porous Media); case A considered all fracture were Power law distribution with Poisson fracture center; case B considered all bedding plans penetrate into modelling region, and remove the bedding count to recalculate joint fracture parameters. Modelling results show that Case B gives stronger groundwater pathways than Case A and have impact on flow field. This preliminary modelling result implicates the groundwater flow modelling work in some fractured sedimentary rock mass, might be considerate to rock sedimentary structure development itself, discontinuous maybe not follow the same stochastic DFN parameter.

  4. Fracture Resistance of Composite Veneers with Different Preparation Designs

    OpenAIRE

    Zlatanovska, Katerina; Guguvcevski, Ljuben; Popovski, Risto; Dimova, Cena; Minovska, Ana; Mijoska, Aneta

    2016-01-01

    Background: The aim of this in vitro study was to examine the fracture load of composite veneers using three different preparation designs. Material and methods: Fifteen extracted, intact, human maxillary central incisors were selected. Teeth were divided into three groups with different preparation design: 1) feather preparation, 2) bevel preparation, and 3) incisal overlap- palatal chamfer. Teeth were restored with composite veneers, and the specimens were loaded to failure. The localizatio...

  5. Sulfidogenesis and Control in Fractured Rock: Laboratory Experiments and Implication for Souring Intervention in Oil Reservoirs

    Science.gov (United States)

    Wu, Y.; Hubbard, C. G.; Geller, J. T.; Ajo Franklin, J. B.

    2016-12-01

    , providing critical insights to the design of field-scale souring control strategies in fractured reservoirs.

  6. Mechanical design optimization of bioabsorbable fixation devices for bone fractures.

    Science.gov (United States)

    Lovald, Scott T; Khraishi, Tariq; Wagner, Jon; Baack, Bret

    2009-03-01

    Bioabsorbable bone plates can eliminate the necessity for a permanent implant when used to fixate fractures of the human mandible. They are currently not in widespread use because of the low strength of the materials and the requisite large volume of the resulting bone plate. The aim of the current study was to discover a minimally invasive bioabsorbable bone plate design that can provide the same mechanical stability as a standard titanium bone plate. A finite element model of a mandible with a fracture in the body region is subjected to bite loads that are common to patients postsurgery. The model is used first to determine benchmark stress and strain values for a titanium plate. These values are then set as the limits within which the bioabsorbable bone plate must comply. The model is then modified to consider a bone plate made of the polymer poly-L/DL-lactide 70/30. An optimization routine is run to determine the smallest volume of bioabsorbable bone plate that can perform and a titanium bone plate when fixating fractures of this considered type. Two design parameters are varied for the bone plate design during the optimization analysis. The analysis determined that a strut style poly-L-lactide-co-DL-lactide plate of 690 mm2 can provide as much mechanical stability as a similar titanium design structure of 172 mm2. The model has determined a bioabsorbable bone plate design that is as strong as a titanium plate when fixating fractures of the load-bearing mandible. This is an intriguing outcome, considering that the polymer material has only 6% of the stiffness of titanium.

  7. Using Chemicals to Optimize Conformance Control in Fractured Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Seright, Randall S.; Liang, Jenn-Tai; Schrader, Richard; Hagstrom II, John; Wang, Ying; Kumar, Ananad; Wavrik, Kathryn

    2001-10-29

    This report describes work performed during the third and final year of the project, Using Chemicals to Optimize Conformance Control in Fractured Reservoirs. This research project had three objectives. The first objective was to develop a capability to predict and optimize the ability of gels to reduce permeability to water more than that to oil or gas. The second objective was to develop procedures for optimizing blocking agent placement in wells where hydraulic fractures cause channeling problems. The third objective was to develop procedures to optimize blocking agent placement in naturally fractured reservoirs.

  8. Wettability Control on Hydro-capillary Fracturing in Granular Media

    Science.gov (United States)

    Trojer, M.; de Anna, P.; Juanes, R.

    2015-12-01

    The flow of two or more immiscible phases within geologic porous media is important in natural and industrial processes like geologic CO2 sequestration, enhanced oil recovery, and hydraulic fracturing. The latter one, however, is a well-known reservoir stimulation technique, by which the permeability of the near-wellbore region is enhanced through the creation of tensile fractures within the rock, formed in the direction perpendicular to the least principal stress. While it is well known that fracturing of granular media strongly depends on the type of media and on the variability of its wetting properties, the effect of wettability on capillary-driven fracturing continues to challenge our microscopic and macroscopic descriptions. Here we study this problem experimentally, starting with the classic experiment of two-phase flow in a horizontal Hele-Shaw cell filled with a granular medium. We inject a low-viscosity fluid into a thin bed of glass beads initially saturated with a fluid 350 times more viscous. We investigate three control parameters: the injection rate of the less-viscous invading phase, the confining stress, and the contact angle, which we control by carefully chosen fluid pairs covering the entire range from drainage to imbibition. Our results demonstrate that wettability exerts a powerful influence on the invasion/fracturing morphology of unfavorable mobility displacements. High time resolution imaging techniques and particle image velocimetry (PIV) allow us to quantify matrix displacement and fracture opening dynamics. Our findings provide insights on fracture propagation, fracture length distribution and the fracture drainage area, parameters which are critically important to better understand long-term hydrocarbon production from shale.

  9. Control of fracture reduction robot using force/torque measurement.

    Science.gov (United States)

    Douke, T; Nakajima, Y; Mori, Y; Onogi, S; Sugita, N; Mitsuishi, M; Bessho, M; Ohhashi, S; Tobita, K; Ohnishi, I; Sakuma, I; Dohi, T; Maeda, Y; Koyama, T; Sugano, N; Yonenobu, K; Matsumoto, Y; Nakamura, K

    2008-01-01

    We have developed a surgical robotic system for femoral fracture reduction employing indirect traction. Indirect traction in fracture reduction is a generally used surgical method for preventing complications such as bone splits caused by high stress on bones. For traction, a patient's foot is gripped by a jig and pulled to the distal side. Indirect traction has the advantage of distributing bone stress by utilizing a strong traction force; however, this procedure does not accurately control the proper positioning of fractured fragments when a surgical robot is used. The human leg has knee and an ankle joints, and thus robotic motion presents problems in not being able to directly propagate reduction motion to a fractured femoral fragment, rendering control of bone position difficult. We propose a control method for fracture reduction robots using external force/torque measurements of the human leg to achieve precise fracture reduction. Results showed that the proposed method reduced repositioning error from 6.8 mm and 15.9 degrees to 0.7 mm and 5.3 degrees, respectively.

  10. Structural controls on anomalous transport in fractured porous rock

    Science.gov (United States)

    Edery, Yaniv; Geiger, Sebastian; Berkowitz, Brian

    2016-07-01

    Anomalous transport is ubiquitous in a wide range of disordered systems, notably in fractured porous formations. We quantitatively identify the structural controls on anomalous tracer transport in a model of a real fractured geological formation that was mapped in an outcrop. The transport, determined by a continuum scale mathematical model, is characterized by breakthrough curves (BTCs) that document anomalous (or "non-Fickian") transport, which is accounted for by a power law distribution of local transition times ψ>(t>) within the framework of a continuous time random walk (CTRW). We show that the determination of ψ>(t>) is related to fractures aligned approximately with the macroscopic direction of flow. We establish the dominant role of fracture alignment and assess the statistics of these fractures by determining a concentration-visitation weighted residence time histogram. We then convert the histogram to a probability density function (pdf) that coincides with the CTRW ψ>(t>) and hence anomalous transport. We show that the permeability of the geological formation hosting the fracture network has a limited effect on the anomalous nature of the transport; rather, it is the fractures transverse to the flow direction that play the major role in forming the long BTC tail associated with anomalous transport. This is a remarkable result, given the complexity of the flow field statistics as captured by concentration transitions.

  11. Applied Control Systems Design

    CERN Document Server

    Mahmoud, Magdi S

    2012-01-01

    Applied Control System Design examines several methods for building up systems models based on real experimental data from typical industrial processes and incorporating system identification techniques. The text takes a comparative approach to the models derived in this way judging their suitability for use in different systems and under different operational circumstances. A broad spectrum of control methods including various forms of filtering, feedback and feedforward control is applied to the models and the guidelines derived from the closed-loop responses are then composed into a concrete self-tested recipe to serve as a check-list for industrial engineers or control designers. System identification and control design are given equal weight in model derivation and testing to reflect their equality of importance in the proper design and optimization of high-performance control systems. Readers’ assimilation of the material discussed is assisted by the provision of problems and examples. Most of these e...

  12. Magnetic induction technique for mapping vertical conductive fractures: electronic design

    Energy Technology Data Exchange (ETDEWEB)

    Landt, J.A.; Koelle, A.R.; Trump, M.A.; Nickell, J.D. Jr.

    1978-09-01

    This report is the last in a series that describes the preliminary design of an instrument capable of mapping conductive fractures deep below the surface of the earth. Earlier reports dealt with theoretical analysis, the general status of the instrument development, and materials vendor searches. Here, attention is focused on the electronics design and prototype hardware to perform the mapping task. A phase-sensitive detector is described that has a sensitivity in the tens of nanovolts. Coil-switching circuitry is also described, as well as a downhole data link tailor-made for this particular instrument's needs.

  13. On the fracture of human dentin: Is it stress- orstrain-controlled?

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, R.K.; Kinney, J.H.; Ritchie, R.O.

    2006-02-01

    Despite substantial clinical interest in the fracture resistance of human dentin, there is little mechanistic information in archival literature that can be usefully used to model such fracture. In fact, although the fracture event indent in, akin to other mineralized tissues like bone, is widely believed to be locally strain-controlled, there has never been any scientific proof to support this belief. The present study seeks to address this issue through the use of a novel set of in vitro experiments in Hanks' balanced salt solution involving a double-notched bend test geometry, which is designed to discern whether the critical failure events involved in the onset of fracture are locally stress- or strain-controlled. Such experiments are further used to characterize the notion of ''plasticity'' in dentin and the interaction of cracks with the salient microstructural features. It is observed that fracture in dentin is indeed locally strain-controlled and that the presence of dentinal tubules does not substantially affect this process of crack initiation and growth. The results presented are believed to be critical steps in the development of a micromechanical model for the fracture of human dentin that takes into consideration the influence of both the microstructure and the local failure mode.

  14. The association between hip fracture and hip osteoarthritis: A case-control study

    Directory of Open Access Journals (Sweden)

    Englund Martin

    2010-11-01

    Full Text Available Abstract Background There have been reports both supporting and refuting an inverse relationship between hip fracture and hip osteoarthritis (OA. We explore this relationship using a case-control study design. Methods Exclusion criteria were previous hip fracture (same side or contralateral side, age younger than 60 years, foreign nationality, pathological fracture, rheumatoid arthritis and cases were radiographic examinations were not found in the archives. We studied all subjects with hip fracture that remained after the exclusion process that were treated at Akureyri University Hospital, Iceland 1990-2008, n = 562 (74% women. Hip fracture cases were compared with a cohort of subjects with colon radiographs, n = 803 (54% women to determine expected population prevalence of hip OA. Presence of radiographic hip OA was defined as a minimum joint space of 2.5 mm or less on an anteroposterior radiograph, or Kellgren and Lawrence grade 2 or higher. Possible causes of secondary osteoporosis were identified by review of medical records. Results The age-adjusted odds ratio (OR for subjects with hip fracture having radiographic hip OA was 0.30 (95% confidence interval [95% CI] 0.12-0.74 for men and 0.33 (95% CI 0.19-0.58 for women, compared to controls. The probability for subjects with hip fracture and hip OA having a secondary cause of osteoporosis was three times higher than for subjects with hip fracture without hip OA. Conclusion The results of our study support an inverse relationship between hip fractures and hip OA.

  15. Induction motor control design

    CERN Document Server

    Marino, Riccardo; Verrelli, Cristiano M

    2010-01-01

    ""Nonlinear and Adaptive Control Design for Induction Motors"" is a unified exposition of the most important steps and concerns in the design of estimation and control algorithms for induction motors. A single notation and modern nonlinear control terminology is used to make the book accessible to readers who are not experts in electric motors at the same time as giving a more theoretical control viewpoint to those who are. In order to increase readability, the book concentrates on the induction motor, eschewing the much more complex and less-well-understood control of asynchronous motors. The

  16. A method for designing plates in treatments of proximal humeral fracture and distal radial fracture

    Directory of Open Access Journals (Sweden)

    Lin Wang

    2016-11-01

    Full Text Available The purpose of this paper was to quickly design fixation plates for fractured proximal humerus and distal radius according to the requirements of surgical treatment. Therefore, a new method to quickly design cloverleaf plate appropriate for proximal humerus and volar plate appropriate for distal radius is put forward. First, three-dimensional (3D reconstruction models of fractured proximal humerus and distal radius were generated based on deforming mean parametric models of proximal humerus and distal radius, respectively. Second, based on region-of-interest marked on the 3D reconstruction model of proximal humerus and distal radius, abutted surfaces of cloverleaf plate and volar plate were established, respectively. Then, parametric abutted surface was established after setting rational parameters for the surface of the cloverleaf plate. Parametric abutted surface of volar plate was established using the same method. Finally, parametric cloverleaf plate and volar plate are generated through thickening their respective parametric abutted surfaces. The parametric plates, acting as templates, accelerate and simplify the design process and therefore allow users to construct plate with editing valid parameters easily. Group of cloverleaf plates and volar plates with different sizes were generated quickly, showing that the proposed method is feasible and effective.

  17. Prediction and Control of Wrinkle and Fracture for Stamping Regular Polygonal Box

    Institute of Scientific and Technical Information of China (English)

    LEI Jun-xiang

    2004-01-01

    Based on the deformation characteristic of regular polygonal box stamped parts and the superfluous triangle material wrinkle model, the criterion of regular polygonal box stamped parts without wrinkle was deduced and used to predict and control the wrinkle limit. According to the fracture model, the criterion of regular polygonal box stamped parts without fracture was deduced and used to predict and control the fracture limit. Combining the criterion for stamping without wrinkle with that without fracture, the stamping criterion of regular polygonal box stamped parts was obtained to predict and control the stamping limit. Taken the stainless steel 0Cr18Ni9 (SUS304) sheet and the square box stamped part as examples, the limit diagram was given to predict and control the wrinkle, fracture and stamping limits. It is suitable for the deep drawing without flange, the deep drawing and stretching combined forming with flange and the rigid punch stretching of plane blank. The limit deep-drawing coefficient and the minimum deep-drawing coefficient can be determined, and the appropriate BHF (blank holder force) and the deep-drawing force can be chosen. These provide a reference for the technology planning, the die and mold design and the equipment determination, and a new criterion evaluating sheet stamping formability, which predicts and controls the stamping process, can be applied to the deep drawing under constant or variable BHF conditions.

  18. Control system design method

    Science.gov (United States)

    Wilson, David G [Tijeras, NM; Robinett, III, Rush D.

    2012-02-21

    A control system design method and concomitant control system comprising representing a physical apparatus to be controlled as a Hamiltonian system, determining elements of the Hamiltonian system representation which are power generators, power dissipators, and power storage devices, analyzing stability and performance of the Hamiltonian system based on the results of the determining step and determining necessary and sufficient conditions for stability of the Hamiltonian system, creating a stable control system based on the results of the analyzing step, and employing the resulting control system to control the physical apparatus.

  19. Nutrient Control Design Manual

    Science.gov (United States)

    The purpose of this EPA design manual is to provide updated, state‐of‐the‐technology design guidance on nitrogen and phosphorus control at municipal Wastewater Treatment Plants (WWTPs). Similar to previous EPA manuals, this manual contains extensive information on the principles ...

  20. Fracture energy of polymer gels with controlled network structures

    Science.gov (United States)

    Akagi, Yuki; Sakurai, Hayato; Gong, Jian Ping; Chung, Ung-il; Sakai, Takamasa

    2013-10-01

    We have investigated the fracture behaviors of tetra-arm polyethylene glycol (Tetra-PEG) gels with controlled network structures. Tetra-PEG gels were prepared by AB-type crosslink-coupling of mutually reactive tetra-arm prepolymers with different concentrations and molecular weights. This series of controlled network structures, for the first time, enabled us to quantitatively examine the Lake-Thomas model, which is the most popular model predicting fracture energies of elastomers. The experimental data showed good agreement with the Lake-Thomas model, and indicated a new molecular interpretation for the displacement length (L), the area around a crack tip within which the network strands are fully stretched. L corresponded to the three times of end-to-end distance of network strands, regardless of all parameters examined. We conclude that the Lake-Thomas model can quantitatively predict the fracture energy of polymer network without trapped entanglements, with the enhancement factor being near 3.

  1. Micromechanical studies of cyclic creep fracture under stress controlled loading

    DEFF Research Database (Denmark)

    van der Giessen, Erik; Tvergaard, Viggo

    1996-01-01

    This paper deals with a study of intergranular failure by creep cavitation under stress-controlled cyclic loading conditions. Loading is assumed to be slow enough that diffusion and creep mechanisms (including grain boundary sliding) dominate, leading to intergranular creep fracture. This study i...

  2. Micromechanical studies of cyclic creep fracture under stress- controlled loading

    NARCIS (Netherlands)

    Giessen, E. van der; Tvergaard, V.

    1996-01-01

    This paper deals with a study of intergranular failure by creep cavitation under stress-controlled cyclic loading conditions. Loading is assumed to be slow enough that diffusion and creep mechanisms (including grain boundary sliding) dominate, leading to intergranular creep fracture. This study is

  3. Using Chemicals to Optimize Conformance Control in Fractured Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Seright, Randall S.; Liang, Jenn-Tai; Schrader, Richard; Hagstrom II, John; Liu, Jin; Wavrik, Kathryn

    1999-09-27

    This report describes work performed during the first year of the project, ''Using Chemicals to Optimize Conformance Control in Fractured Reservoirs.'' This research project has three objectives. The first objective is to develop a capability to predict and optimize the ability of gels to reduce permeability to water more than that to oil or gas. The second objective is to develop procedures for optimizing blocking agent placement in wells where hydraulic fractures cause channeling problems. The third objective is to develop procedures to optimize blocking agent placement in naturally fractured reservoirs. This research project consists of three tasks, each of which addresses one of the above objectives. Our work is directed at both injection wells and production wells and at vertical, horizontal, and highly deviated wells.

  4. Mass transfer controlled by fracturing in micritic carbonate rocks

    Science.gov (United States)

    Richard, James; Coulon, Michel; Gaviglio, Patrick

    2002-05-01

    The fractured Coniacian chalk from the Omey area (Paris Basin, France) displays strong evidence of modifications controlled by brittle deformation. Fracturing is associated with important changes in pore space (decrease in total porosity and pore interconnection, change in distribution of pore access diameters and capillary characteristics), nannofacies (gradual evolution from a point-contact fabric to a welded, interlocked or coalescent fabric) and chemical composition (Sr concentration decrease). These modifications result from fluid-rock interaction that control significant mass transfer (percentage of secondary calcite >50%). Sr is a remarkable indicator of these mass transfers. Sr analyses allowed us to prove that the deformed zone (26.7 m) is wider than the fractured zone (11.3 m). They also indicate that the footwall block is less affected than the hanging wall block. A physicochemical model of the deformation mechanism is proposed. It shows that a cyclic process of fracturing controls the temporal evolution of the fluid saturation and fluid pressure and, consequently, the mass transfer.

  5. Vitamin D in Foot and Ankle Fracture Healing: A Literature Review and Research Design.

    Science.gov (United States)

    Bernhard, Andrew; Matuk, Jorge

    2015-10-01

    Vitamin D is a generic name for a group of essential vitamins, or secosteroids, important in calcium homeostasis and bone metabolism. Specifically, efficacy of vitamin D with regard to bone healing is in question. A literature review was performed, finding mostly large studies involving vitamin D effects on prevention of fractures and randomized animal model studies consisting of controlled fractures with vitamin D interventions. The prevention articles generally focus on at-risk populations, including menopausal women and osteoporotic patients, and also most often include calcium in the treatment group. Few studies look at vitamin D specifically. The animal model studies often focus more on vitamin D supplementation; however the results are still largely inconclusive. While recent case reports appear promising, the ambiguity of results on the topic of fracture healing suggests a need for more, higher level research. A novel study design is proposed to help determine the efficacy on vitamin D in fracture healing. Therapeutic, Level IV: Systematic Review. © 2015 The Author(s).

  6. Pattern Recognition Control Design

    Science.gov (United States)

    Gambone, Elisabeth A.

    2018-01-01

    Spacecraft control algorithms must know the expected vehicle response to any command to the available control effectors, such as reaction thrusters or torque devices. Spacecraft control system design approaches have traditionally relied on the estimated vehicle mass properties to determine the desired force and moment, as well as knowledge of the effector performance to efficiently control the spacecraft. A pattern recognition approach was used to investigate the relationship between the control effector commands and spacecraft responses. Instead of supplying the approximated vehicle properties and the thruster performance characteristics, a database of information relating the thruster ring commands and the desired vehicle response was used for closed-loop control. A Monte Carlo simulation data set of the spacecraft dynamic response to effector commands was analyzed to establish the influence a command has on the behavior of the spacecraft. A tool developed at NASA Johnson Space Center to analyze flight dynamics Monte Carlo data sets through pattern recognition methods was used to perform this analysis. Once a comprehensive data set relating spacecraft responses with commands was established, it was used in place of traditional control methods and gains set. This pattern recognition approach was compared with traditional control algorithms to determine the potential benefits and uses.

  7. Effect of connector design on the fracture resistance of all-ceramic fixed partial dentures.

    Science.gov (United States)

    Oh, Won-Suck; Anusavice, Kenneth J

    2002-05-01

    Fracture of all-ceramic fixed partial dentures (FPDs) tends to occur in the connector area. The objective of this study was to test the hypothesis that the radii of curvature at the connector affects the fracture resistance of 3-unit FPDs. With the use of a standardized silicone mold, 40 three-unit FPD wax patterns were fabricated with the same dimensions and divided into 4 groups of 10 specimens per group. Each pattern was modified at the connector areas of the occlusal embrasure (OE) and the gingival embrasure (GE); 2 wax carvers with radii of curvature at their tips of 0.90 mm and 0.25 mm were used. The dimensions of the connectors were standardized with an electronic caliper to 4 +/- 0.12 mm in height and 5 +/- 0.13 mm in width. Connector designs were as follows: Design I: OE and GE 0.90 mm; Design II: OE 0.90 mm and GE 0.25 mm; Design III: OE 0.25 mm and GE 0.90 mm; and Design IV (control): OE and GE 0.25 mm. An experimental hot-pressed core ceramic was used to make the FPD frameworks, which were consequently cemented on epoxy dies with dual-polymerizing composite (Variolink II) and loaded to fracture in a universal testing machine at a crosshead speed of 0.5 mm/min. The failure load data were analyzed with analysis of variance (ANOVA; P=.05) and Duncan's test (alpha=.01). The mean failure loads and standard deviations were as follows: 943 +/- 151 N for Design I; 746 +/- 106 N for Design II; 944 +/- 144 N for Design III; and 673 +/- 55 N for Design IV. ANOVA revealed a significant difference (P< or = .0001) between the mean failure loads of different connector designs. The mean loads to failure for Designs I and III were significantly higher than those for Designs II and IV (Duncan's test). Within the limitations of this study and for the experimental ceramic tested, as the radius at the gingival embrasure increased from 0.25 to 0.90 mm, the mean failure load increased by 140%. The radius of curvature at the occlusal embrasure had only a minor effect on the

  8. Probabilistic Fracture Mechanics and Optimum Fracture Control Analytical Procedures for a Reusable Solid Rocket Motor Case

    Science.gov (United States)

    Hanagud, S.; Uppaluri, B.

    1977-01-01

    A methodology for the reliability analysis of a reusable solid rocket motor case is discussed. The analysis is based on probabilistic fracture mechanics and probability distribution for initial flaw sizes. The developed reliability analysis is used to select the structural design variables of the solid rocket motor case on the basis of minimum expected cost and specified reliability bounds during the projected design life of the case. Effects of failure prevention plans such as nondestructive inspection and the material erosion between missions are also considered in the developed procedure for selection of design variables. The reliability-based procedure can be modified to consider other similar structures of reusable space vehicle systems with different failure prevention plans.

  9. Protocol for a randomized controlled trial on risk adapted damage control orthopedic surgery of femur shaft fractures in multiple trauma patients

    Directory of Open Access Journals (Sweden)

    Rixen Dieter

    2009-08-01

    Full Text Available Abstract Background Fractures of the long bones and femur fractures in particular are common in multiple trauma patients, but the optimal management of femur fractures in these patients is not yet resolved. Although there is a trend towards the concept of "Damage Control Orthopedics" (DCO in the management of multiple trauma patients with long bone fractures as reflected by a significant increase in primary external fixation of femur fractures, current literature is insufficient. Thus, in the era of "evidence-based medicine", there is the need for a more specific, clarifying trial. Methods/Design The trial is designed as a randomized controlled open-label multicenter study. Multiple trauma patients with femur shaft fractures and a calculated probability of death between 20 and 60% will be randomized to either temporary fracture fixation with fixateur externe and defined secondary definitive treatment (DCO or primary reamed nailing (early total care. The primary objective is to reduce the extent of organ failure as measured by the maximum sepsis-related organ failure assessment (SOFA score. Discussion The Damage Control Study is the first to evaluate the risk adapted damage control orthopedic surgery concept of femur shaft fractures in multiple trauma patients in a randomized controlled design. The trial investigates the differences in clinical outcome of two currently accepted different ways of treating multiple trauma patients with femoral shaft fractures. This study will help to answer the question whether the "early total care" or the „damage control” concept is associated with better outcome. Trial registration Current Controlled Trials ISRCTN10321620

  10. Early age fracture properties of microstructurally-designed mortars

    DEFF Research Database (Denmark)

    Di Bella, Carmelo; Michel, Alexander; Stang, Henrik;

    2017-01-01

    This paper compares the fracture properties as well as crack initiation and propagation of real and equivalent mortars. The development of the elastic modulus, tensile strength, and fracture energy at different hydration stages were determined by inverse analysis of load-displacement curves obtai...

  11. Influence of the preparation design and artificial aging on the fracture resistance of monolithic zirconia crowns

    OpenAIRE

    Mitov, Gergo; Anastassova-Yoshida, Yana; Nothdurft, Frank Phillip; von See, Constantin; Pospiech, Peter

    2016-01-01

    PURPOSE The aim of this study was to evaluate the fracture resistance and fracture behavior of monolithic zirconia crowns in accordance with the preparation design and aging simulation method. MATERIALS AND METHODS An upper first molar was prepared sequentially with three different preparation designs: shoulderless preparation, 0.4 mm chamfer and 0.8 mm chamfer preparation. For each preparation design, 30 monolithic zirconia crowns were fabricated. After cementation on Cr-Co alloy dies, the f...

  12. A flexible and highly pressure-sensitive graphene-polyurethane sponge based on fractured microstructure design.

    Science.gov (United States)

    Yao, Hong-Bin; Ge, Jin; Wang, Chang-Feng; Wang, Xu; Hu, Wei; Zheng, Zhi-Jun; Ni, Yong; Yu, Shu-Hong

    2013-12-10

    A fractured microstructure design: A new type of piezoresistive sensor with ultra-high-pressure sensitivity (0.26 kPa(-1) ) in low pressure range (<2 kPa) and minimum detectable pressure of 9 Pa has been fabricated using a fractured microstructure design in a graphene-nanosheet-wrapped polyurethane (PU) sponge. This low-cost and easily scalable graphene-wrapped PU sponge pressure sensor has potential application in high-spatial-resolution, artificial skin without complex nanostructure design.

  13. Applications of fatigue and fracture tolerant design concepts in the nuclear power industry

    Energy Technology Data Exchange (ETDEWEB)

    Jones, R.L.; Marston, T.U.; Tagart, S.W.; Norris, D.M.; Nickell, R.E.

    1982-01-01

    To assure the integrity of nuclear power plant components, fatigue and fracture tolerant design concepts have been incorporated in Sections III and XI of the ASME Code; these contain requirements for nuclear power plant design, construction, and in-service inspection. The methods used in the Code to design against fatigue and brittle fracture are described together with the fracture mechanics based procedure suggested in Sections XI for the evaluation of flaws detected by in-service inspections. Some aspects of the present Code methods that could probably be improved are identified. 19 refs.

  14. Partnership for fragility bone fracture care provision and prevention program (P4Bones: study protocol for a secondary fracture prevention pragmatic controlled trial

    Directory of Open Access Journals (Sweden)

    Gaboury Isabelle

    2013-01-01

    Full Text Available Abstract Background Fractures associated with bone fragility in older adults signal the potential for secondary fracture. Fragility fractures often precipitate further decline in health and loss of mobility, with high associated costs for patients, families, society and the healthcare system. Promptly initiating a coordinated, comprehensive pharmacological bone health and falls prevention program post-fracture may improve osteoporosis treatment compliance; and reduce rates of falls and secondary fractures, and associated morbidity, mortality and costs. Methods/design This pragmatic, controlled trial at 11 hospital sites in eight regions in Quebec, Canada, will recruit community-dwelling patients over age 50 who have sustained a fragility fracture to an intervention coordinated program or to standard care, according to the site. Site study coordinators will identify and recruit 1,596 participants for each study arm. Coordinators at intervention sites will facilitate continuity of care for bone health, and arrange fall prevention programs including physical exercise. The intervention teams include medical bone specialists, primary care physicians, pharmacists, nurses, rehabilitation clinicians, and community program organizers. The primary outcome of this study is the incidence of secondary fragility fractures within an 18-month follow-up period. Secondary outcomes include initiation and compliance with bone health medication; time to first fall and number of clinically significant falls; fall-related hospitalization and mortality; physical activity; quality of life; fragility fracture-related costs; admission to a long term care facility; participants’ perceptions of care integration, expectations and satisfaction with the program; and participants’ compliance with the fall prevention program. Finally, professionals at intervention sites will participate in focus groups to identify barriers and facilitating factors for the integrated

  15. Fatigue and fracture resistance of zirconia crowns prepared with different finish line designs.

    Science.gov (United States)

    Aboushelib, Moustafa N

    2012-01-01

    The aim of this study was to evaluate the effect of finish line design on the fatigue, fracture resistance, and failure type of veneered zirconia restorations. A CAD/CAM system (Cercon) was used to prepare zirconia frameworks (0.5 mm thick) for a maxillary central incisor. Three finish line designs were evaluated: a complete narrow chamfer, a narrow chamfer with a lingual ledge, and a complete ledge. The prepared frameworks were veneered using a press-on ceramic (Ceram Press) and were cemented on the corresponding prepared teeth using a resin cement (Panavia F2.0). The cemented specimens were thermocycled, subjected to dynamic fatigue, and finally loaded till fracture. Fractured specimens were examined under a scanning electron microscope to assess fracture type. One-way ANOVA and Bonferroni post hoc tests were used to analyze the data (α= 0.05). The finish line design did not have any significant statistical influence on the fracture resistance (F = 1.9, p= 0.346) or on the failure type of the tested specimens. Adjusted R squared value (R = 0.049) indicated a weak correlation between finish line design and fracture load of the tested specimens. All specimens failed due to cracking and fracture of the veneer ceramic. Meanwhile, the framework remained entirely intact. Three narrow chamfer finish line specimens demonstrated adhesive fracture of the veneer ceramic during dynamic fatigue testing, related to overextension of the veneer ceramic during the layering procedure. Within the limitations of this study, the finish line design did not influence the fatigue or the fracture resistance of veneered zirconia crowns. Selection of any of the finish line designs should be based on the clinical condition of the restored tooth. © 2011 by the American College of Prosthodontists.

  16. Design and Implementation of Energized Fracture Treatment in Tight Gas Sands

    Energy Technology Data Exchange (ETDEWEB)

    Mukul Sharma; Kyle Friehauf

    2009-12-31

    , the minimum CO{sub 2} gas quality (volume % of gas) recommended is 30% for moderate differences between fracture and reservoir pressures (2900 psi reservoir, 5300 psi fracture). The minimum quality is reduced to 20% when the difference between pressures is larger, resulting in additional gas expansion in the invaded zone. Inlet fluid temperature, flow rate, and base viscosity did not have a large impact on fracture production. Finally, every stage of the fracturing treatment should be energized with a gas component to ensure high gas saturation in the invaded zone. A second, more general, sensitivity study was conducted. Simulations show that CO{sub 2} outperforms N{sub 2} as a fluid component because it has higher solubility in water at fracturing temperatures and pressures. In fact, all gas components with higher solubility in water will increase the fluid's ability to reduce damage in the invaded zone. Adding methanol to the fracturing solution can increase the solubility of CO{sub 2}. N{sub 2} should only be used if the gas leaks-off either during the creation of the fracture or during closure, resulting in gas going into the invaded zone. Experimental data is needed to determine if the gas phase leaks-off during the creation of the fracture. Simulations show that the bubbles in a fluid traveling across the face of a porous medium are not likely to attach to the surface of the rock, the filter cake, or penetrate far into the porous medium. In summary, this research has created the first compositional fracturing simulator, a useful tool to aid in energized fracture design. We have made several important and original conclusions about the best practices when using energized fluids in tight gas sands. The models and tools presented here may be used in the future to predict behavior of any multi-phase or multi-component fracturing fluid system.

  17. On the fracture of human dentin: Is it stress- orstrain-controlled?

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, R.K.; Kinney, J.H.; Ritchie, R.O.

    2006-02-01

    Despite substantial clinical interest in the fractureresistance of human dentin, there is little mechanistic information inarchival literature that can be usefully used to model such fracture. Infact, although the fracture event indent in, akin to other mineralizedtissues like bone, is widely believed to be locally strain-controlled,there has never been any scientific proof to support this belief. Thepresent study seeks to address this issue through the use of a novel setof in vitro experiments in Hanks' balanced salt solution involving adouble-notched bend test geometry, which is designed to discern whetherthe critical failure events involved in the onset of fracture are locallystress- or strain-controlled. Such experiments are further used tocharacterize the notion of "plasticity" in dentin and the interaction ofcracks with the salient microstructural features. It is observed thatfracture in dentin is indeed locally strain-controlled and that thepresence of dentinal tubules does not substantially affect this processof crack initiation and growth. The results presented are believed to becritical steps in the development ofa micromechanical model for thefracture of human dentin that takes into consideration the influence ofboth the microstructure and the local failure mode.

  18. Fracture controls on valley persistence: the Cairngorm Granite pluton, Scotland

    Science.gov (United States)

    Hall, A. M.; Gillespie, M. R.

    2016-12-01

    Valleys are remarkably persistent features in many different tectonic settings, but the reasons for this persistence are rarely explored. Here, we examine the structural controls on valleys in the Cairngorms Mountains, Scotland, part of the passive margin of the eastern North Atlantic. We consider valleys at three scales: straths, glens and headwater valleys. The structural controls on valleys in and around the Cairngorm Granite pluton were examined on satellite and aerial photographs and by field survey. Topographic lineaments, including valleys, show no consistent orientation with joint sets or with sheets of microgranite and pegmatitic granite. In this granite landscape, jointing is not a first-order control on valley development. Instead, glens and headwater valleys align closely to quartz veins and linear alteration zones (LAZs). LAZs are zones of weakness in the granite pluton in which late-stage hydrothermal alteration and hydro-fracturing have greatly reduced rock mass strength and increased permeability. LAZs, which can be kilometres long and >700 m deep, are the dominant controls on the orientation of valleys in the Cairngorms. LAZs formed in the roof zone of the granite intrusion. Although the Cairngorm pluton was unroofed soon after emplacement, the presence of Old Red Sandstone (ORS) outliers in the terrain to the north and east indicates that the lower relief of the sub-ORS basement surface has been lowered by 1 km of vertical erosion and for 400 Myr. This valley persistence is a combined product of regionally low rates of basement exhumation and of the existence of LAZs in the Cairngorm pluton and sub-parallel Caledonide fractures in the surrounding terrain with depths that exceed 1 km.

  19. Knee-extension strength, postural control and function are related to fracture type and thigh edema in patients with hip fracture

    DEFF Research Database (Denmark)

    Kristensen, Morten T; Bandholm, Thomas; Bencke, Jesper

    2008-01-01

    BACKGROUND: Post-surgery thigh edema, loss of knee-extension strength, and reduced physical performance are common following a hip fracture. It is not known if knee-extension strength and physical performance are related to the edema and fracture type. The aim of this study was to examine...... the influence of fracture type and post-surgery edema on physical performances in patients with hip fracture. METHODS: Fifteen women and five men admitted from their own home to an acute orthopedic hip fracture unit were examined. Ten had cervical and ten had intertrochanteric fractures. Correlations between...... fracture type and thigh edema in the fractured limb (% non-fractured) to physical performances of basic mobility, postural control (sway), and isometric knee-extension strength were examined. All measures, except those of basic mobility, were conducted at the time of discharge, 8.5 days post...

  20. Pulsed Electromagnetic Fields in the treatment of fresh scaphoid fractures. A multicenter, prospective, double blind, placebo controlled, randomized trial

    Directory of Open Access Journals (Sweden)

    Poeze Martijn

    2011-05-01

    Full Text Available Abstract Background The scaphoid bone is the most commonly fractured of the carpal bones. In the Netherlands 90% of all carpal fractures is a fracture of the scaphoid bone. The scaphoid has an essential role in functionality of the wrist, acting as a pivot. Complications in healing can result in poor functional outcome. The scaphoid fracture is a troublesome fracture and failure of treatment can result in avascular necrosis (up to 40%, non-union (5-21% and early osteo-arthritis (up to 32% which may seriously impair wrist function. Impaired consolidation of scaphoid fractures results in longer immobilization and more days lost at work with significant psychosocial and financial consequences. Initially Pulsed Electromagnetic Fields was used in the treatment of tibial pseudoarthrosis and non-union. More recently there is evidence that physical forces can also be used in the treatment of fresh fractures, showing accelerated healing by 30% and 71% reduction in nonunion within 12 weeks after initiation of therapy. Until now no double blind randomized, placebo controlled trial has been conducted to investigate the effect of this treatment on the healing of fresh fractures of the scaphoid. Methods/Design This is a multi center, prospective, double blind, placebo controlled, randomized trial. Study population consists of all patients with unilateral acute scaphoid fracture. Pregnant women, patients having a life supporting implanted electronic device, patients with additional fractures of wrist, carpal or metacarpal bones and pre-existing impairment in wrist function are excluded. The scaphoid fracture is diagnosed by a combination of physical and radiographic examination (CT-scanning. Proven scaphoid fractures are treated with cast immobilization and a small Pulsed Electromagnetic Fields bone growth stimulating device placed on the cast. Half of the devices will be disabled at random in the factory. Study parameters are clinical consolidation

  1. Prevalence of overweight in children with bone fractures: a case control study

    Directory of Open Access Journals (Sweden)

    Valerio Giuliana

    2012-10-01

    Full Text Available Abstract Background Children's fractures have been enlisted among orthopaedics complaints of childhood obesity. Unhealthy lifestyle behaviours may contribute to increased risk. This study described the prevalence of overweight/obesity in children and adolescents reporting a recent fracture in relation to gender, dynamic of trauma, and site of fracture. Methods Four-hundred-forty-nine children and adolescents with fracture and 130 fracture-free controls were recruited from a large children’s hospital. The interaction between overweight and gender, dynamic of trauma, site of fracture was explored. Sports participation, television viewing, and calcium intake were also investigated. Results Overweight/obesity rate was increased in girls with fracture either at the upper or the lower limb (p= 0.004, while it was increased only in boys with fracture at the lower limb (p Conclusions The increased prevalence of overweight/obesity in children with fractures is related to gender and site of fracture. Higher levels of sedentary behaviours characterize overweight children reporting fractures.

  2. The Effects of New Design of Access Hole on Porcelain Fracture Resistance of Implant-Supported Crowns

    Directory of Open Access Journals (Sweden)

    Reza Derafshi

    2015-03-01

    Full Text Available Statement of the Problem: One disadvantage of cement-retained crowns is the lack of predictable irretrievability. This problem can be overcome through designing a screw access hole in the metal substructure of cement-retained restora-tion and using porcelain stain to define this area. Purpose: This study aimed to evaluate the influence of existence of screw access hole on porcelain fracture resistance of metal-ceramic implant-supported crowns. Materials and Method: Thirty six standardized metal-ceramic crowns were fabri-cated and divided into 3 groups (n=12; group 1 conventional cement-retained metal-ceramic crowns as control group, group 2 cement-retained MC crowns in which porcelain stain was used to define the location of screw access channel, and group 3 cement-retained metal-ceramic crowns in the metal substructure of which a hole and ledge was designed in the location of screw access channel. The specimens were cemented (TempBond, Kerr to their dedicated abutments. A hole was made in the location of screw access channel in group 2 and 3 and filled with photo-polymerized composite resin (3M; ESPE. All specimens were thermocycled and loaded in universal testing machine at crosshead speed of 2mm/min until fracture. Mean values of load at fracture were calculated in each group and compared with One-way ANOVA (α=0.05. Results: Mean value of the load required to fracture the restorations was 1947±487 N in group 1, 1927±539 N in group 2, and 2170±738 N in group 3. No statistically significant difference was found between the fracture resistance values of the three groups (p> 0.05 Conclusion: Presence of screw access channel in cement-retained implant restora-tions does not compromise fracture resistance.

  3. Design of Controllers for Liquid Level Control

    Directory of Open Access Journals (Sweden)

    Augustin Simon,

    2015-08-01

    Full Text Available The liquid level control system is commonly used in many process control applications. The aim of the process is to keep the liquid level in the tank at the desired value. The conventional proportional-integral-derivative (PID controller is simple, reliable and eliminates the error rate but it cannot handle complex problems. Fuzzy logic controllers are rule based systems which simulates human behavior of the process. The fuzzy controller is combined with the PID controller and then applied to the tank level control system. This paper proposes Inverse fuzzy with fuzzy logic controller for controlling liquid level system for a plant. This paper also compares the transient response as well as error indices of PID, Fuzzy logic controller, inverse fuzzy controllers. The responses of the controllers are verified through simulation. From the simulation results, it is observed that inverse fuzzy-PID controller gives the superior performance than the other controllers. The inverse fuzzy-PID controller gives better performance than the PID and fuzzy controller in terms of overshoot and settling time. Performance analysis is carried out with Liquid Flow Control System Design with Fuzzy logic controller. Results are evaluated by comparing the response time of conventional PID, fuzzy logic and Inverse fuzzy controller. Comparative analysis of the performance of different controllers is done in MATLAB and Simulink.

  4. Earthquake design for controlled structures

    Directory of Open Access Journals (Sweden)

    Nikos G. Pnevmatikos

    2017-04-01

    Full Text Available An alternative design philosophy, for structures equipped with control devices, capable to resist an expected earthquake while remaining in the elastic range, is described. The idea is that a portion of the earthquake loading is under¬taken by the control system and the remaining by the structure which is designed to resist elastically. The earthquake forces assuming elastic behavior (elastic forces and elastoplastic behavior (design forces are first calculated ac¬cording to the codes. The required control forces are calculated as the difference from elastic to design forces. The maximum value of capacity of control devices is then compared to the required control force. If the capacity of the control devices is larger than the required control force then the control devices are accepted and installed in the structure and the structure is designed according to the design forces. If the capacity is smaller than the required control force then a scale factor, α, reducing the elastic forces to new design forces is calculated. The structure is redesigned and devices are installed. The proposed procedure ensures that the structure behaves elastically (without damage for the expected earthquake at no additional cost, excluding that of buying and installing the control devices.

  5. The Vitamin D Assessment (ViDA) Study: design of a randomized controlled trial of vitamin D supplementation for the prevention of cardiovascular disease, acute respiratory infection, falls and non-vertebral fractures.

    Science.gov (United States)

    Scragg, Robert; Waayer, Debbie; Stewart, Alistair W; Lawes, Carlene M M; Toop, Les; Murphy, Judy; Khaw, Kay-Tee; Camargo, Carlos A

    2016-11-01

    Observational studies have shown that low vitamin D status is associated with an increased risk of cardiovascular disease, acute respiratory infection, falls and non-vertebral fractures. We recruited 5110 Auckland adults, aged 50-84 years, into a randomized, double-blind, placebo-controlled trial to test whether vitamin D supplementation protects against these four major outcomes. The intervention is a monthly cholecalciferol dose of 100,000IU (2.5mg) for an estimated median 3.3 years (range 2.5-4.2) during 2011-2015. Participants were recruited primarily from family practices, plus community groups with a high proportion of Maori, Pacific, or South Asian individuals. The baseline evaluation included medical history, lifestyle, physical measurements (e.g. blood pressure, arterial waveform, lung function, muscle function), and a blood sample (stored at -80°C for later testing). Capsules are being mailed to home addresses with a questionnaire to collect data on non-hospitalized outcomes and to monitor adherence and potential adverse effects. Other data sources include New Zealand Ministry of Health data on mortality, hospitalization, cancer registrations and dispensed pharmaceuticals. A random sample of 438 participants returned for annual collection of blood samples to monitor adherence and safety (hypercalcemia), including repeat physical measurements at 12 months follow-up. The trial will allow testing of a priori hypotheses on several other endpoints including: weight, blood pressure, arterial waveform parameters, heart rate variability, lung function, muscle strength, gait and balance, mood, psoriasis, bone density, and chronic pain.

  6. Teaching medical device design using design control.

    Science.gov (United States)

    May-Newman, Karen; Cornwall, G Bryan

    2012-01-01

    The design of medical devices requires an understanding of a large number of factors, many of which are difficult to teach in the traditional educational format. This subject benefits from using a challenge-based learning approach, which provides focused design challenges requiring students to understand important factors in the context of a specific device. A course was designed at San Diego State University (CA, USA) that applied challenge-based learning through in-depth design challenges in cardiovascular and orthopedic medicine, and provided an immersive field, needs-finding experience to increase student engagement in the process of knowledge acquisition. The principles of US FDA 'design control' were used to structure the students' problem-solving approach, and provide a format for the design documentation, which was the basis of grading. Students utilized a combination of lecture materials, industry guest expertise, texts and readings, and internet-based searches to develop their understanding of the problem and design their solutions. The course was successful in providing a greatly increased knowledge base and competence of medical device design than students possessed upon entering the course.

  7. Design for controllability

    OpenAIRE

    Tsukaya, Hirokazu

    2012-01-01

    The safety of genetically modified crops remains a contested issue, given the potential risk for human health and the environment. To further reduce any risks and alleviate public concerns, terminator technology could be used both to tag and control genetically modified plants.

  8. New miniplate for osteosynthesis of mandibular angle fractures designed to improve formation of new bone.

    Science.gov (United States)

    Pituru, Teodora Silagieva; Bucur, Alexandru; Gudas, Claudiu; Pituru, Silviu-Mirel; Marius Dinca, Octavian

    2016-04-01

    The purpose of this article is to present the study of a new miniplate designed to keep the maximum strains developed in the cortical bone near the fracture line during accidental biting to values below the threshold causing bone resorption. Designed to offer maximum fracture stability with minimal implanted volume and patient intrusion, the design uses a novel approach to account for the effects of the distance from the fracture line to the nearest screws. Its geometry minimizes the peak forces that can develop during most cases of mandible biomechanical loadings. A three-dimensional (3D) osteosynthesis finite element model for a human mandible confirmed the operational effectiveness of the miniplate. It also provided numerical estimates for the strains and screw forces in the cortical surface during incisor bites with clinically relevant forces of 200 N. Two prototypes, 0.6 mm and 0.8 mm in thickness, were repeatedly tested on fractured sheep mandibles, fixed in a purpose-built jig, to loads up to 150% of the maximum forces developed by human patients. The tests indicated good fracture stability, and the proof tests carried for each of the two prototypes terminated at more than 350 N due to failure of the loading cable and respectively, secondary mandible fractures occurring away from the miniplate.

  9. The operative treatment of complex pilon fractures: A strategy of soft tissue control

    Directory of Open Access Journals (Sweden)

    Xianfeng He

    2013-01-01

    Full Text Available Background: Pilon fractures are challenging to manage because of the complexity of the injury pattern and the risk of significant complications. The soft tissue injury and handling of the soft tissue envelope are crucial in pilon fracture outcomes. The purpose of this study was to evaluate the early rate of complications using the strategy of "soft tissue control" for operative treatment of complex pilon fractures. Materials and Methods: 36 complex pilon fractures were treated with the "soft tissue control" strategy. Patients followed the standard staged protocol, anterolateral approach to the distal tibia, the "no-touch" technique and incisional negative pressure wound therapy for pilon fractures. Patients were examined clinically at 2-3 weeks and then 8 weeks for complications associated with the surgical technique. Results: All fractures were AO/OTA (Orthopaedic Trauma Association type C fractures (61% C3, 22% C2 and 16% C1. Only one patient developed superficial infection and resolved with antibiotics and local wound care. None developed deep infection. Conclusions: The strategy of soft tissue control for treatment of pilon fractures resulted in relatively low incidence of early wound complications in patients with complex pilon fractures.

  10. Influence of cavity preparation design on fracture resistance of posterior Leucite-reinforced ceramic restorations.

    Science.gov (United States)

    Soares, Carlos Jose; Martins, Luis Roberto Marcondes; Fonseca, Rodrigo Borges; Correr-Sobrinho, Lourenco; Fernandes Neto, Alfredo Julio

    2006-06-01

    Controversy exists concerning the preferred cavity design for posterior ceramic restorations to improve their resistance to fracture under occlusal load. The aim of this study was to assess the resistance to fracture of leucite-reinforced ceramic restorations placed on molars with different cavity preparation designs. Ninety noncarious molars were selected, stored in 0.2% thymol solution, and divided into 9 groups (n = 10): IT, intact teeth; CsI, conservative inlay; ExI, extensive inlay; CsO/mb, conservative onlay with mesio-buccal cusp coverage; ExO/mb, entensive onlay with mesio-buccal cusp coverage; CsO/b, conservative onlay with buccal cusp coverage; ExO/b, entensive onlay with buccal cusp coverage; CsO/t, conservative onlay with total cusp coverage; ExO/t, extensive onlay with total cusp coverage. Teeth were restored with a Leucite-reinforced ceramic (Cergogold). The fracture resistance (N) was assessed under compressive load in a universal testing machine. The data were analyzed with 1-way and 2-way analyses of variance, followed by the Tukey HSD test (alpha = .05). Fracture modes were recorded, based on the degree of tooth structure and restoration damage. One-way analysis showed that intact teeth had the highest fracture resistance values. Two-way analyses showed no significant differences for the isthmus extention factor, but showed a significant difference for the preparation design type of fracture (P = .03), and also for the interaction between both factors (P = .013). The fracture mode observed in all groups tended to involve only restorations. Within the limitations of this study, it was observed that cuspal coverage does not increase fracture resistance of the posterior tooth-restoration complex restored with leucite-reinforced ceramics.

  11. Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda

    Energy Technology Data Exchange (ETDEWEB)

    Pyrak-Nolte, Laura J [Purdue Univ., West Lafayette, IN (United States); DePaolo, Donald J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Pietraß, Tanja [USDOE Office of Science, Washington, DC (United States)

    2015-05-22

    From beneath the surface of the earth, we currently obtain about 80-percent of the energy our nation consumes each year. In the future we have the potential to generate billions of watts of electrical power from clean, green, geothermal energy sources. Our planet’s subsurface can also serve as a reservoir for storing energy produced from intermittent sources such as wind and solar, and it could provide safe, long-term storage of excess carbon dioxide, energy waste products and other hazardous materials. However, it is impossible to underestimate the complexities of the subsurface world. These complexities challenge our ability to acquire the scientific knowledge needed for the efficient and safe exploitation of its resources. To more effectively harness subsurface resources while mitigating the impacts of developing and using these resources, the U.S. Department of Energy established SubTER – the Subsurface Technology and Engineering RD&D Crosscut team. This DOE multi-office team engaged scientists and engineers from the national laboratories to assess and make recommendations for improving energy-related subsurface engineering. The SubTER team produced a plan with the overall objective of “adaptive control of subsurface fractures and fluid flow.”This plan revolved around four core technological pillars—Intelligent Wellbore Systems that sustain the integrity of the wellbore environment; Subsurface Stress and Induced Seismicity programs that guide and optimize sustainable energy strategies while reducing the risks associated with subsurface injections; Permeability Manipulation studies that improve methods of enhancing, impeding and eliminating fluid flow; and New Subsurface Signals that transform our ability to see into and characterize subsurface systems. The SubTER team developed an extensive R&D plan for advancing technologies within these four core pillars and also identified several areas where new technologies would require additional basic research

  12. Clastic patterned ground in Lomonosov crater, Mars: examining fracture controlled formation mechanisms

    Science.gov (United States)

    Barrett, Alexander M.; Balme, Matthew R.; Patel, Manish R.; Hagermann, Axel

    2017-10-01

    The area surrounding Lomonosov crater on Mars has a high density of seemingly organised boulder patterns. These form seemingly sorted polygons and stripes within kilometre scale blockfields, patches of boulder strewn ground which are common across the Martian high latitudes. Several hypotheses have been suggested to explain the formation of clastic patterned ground on Mars. It has been proposed that these structures could have formed through freeze-thaw sorting, or conversely by the interaction of boulders with underlying fracture polygons. In this investigation a series of sites were examined to evaluate whether boulder patterns appear to be controlled by the distribution of underlying fractures and test the fracture control hypotheses for their formation. It was decided to focus on this suite of mechanisms as they are characterised by a clear morphological relationship, namely the presence of an underlying fracture network which can easily be evaluated over a large area. It was found that in the majority of examples at these sites did not exhibit fracture control. Although fractures were present at many sites there were very few sites where the fracture network appeared to be controlling the boulder distribution. In general these were not the sites with the best examples of organization, suggesting that the fracture control mechanisms are not the dominant geomorphic process organising the boulders in this area.

  13. Integrated controls design optimization

    Science.gov (United States)

    Lou, Xinsheng; Neuschaefer, Carl H.

    2015-09-01

    A control system (207) for optimizing a chemical looping process of a power plant includes an optimizer (420), an income algorithm (230) and a cost algorithm (225) and a chemical looping process models. The process models are used to predict the process outputs from process input variables. Some of the process in puts and output variables are related to the income of the plant; and some others are related to the cost of the plant operations. The income algorithm (230) provides an income input to the optimizer (420) based on a plurality of input parameters (215) of the power plant. The cost algorithm (225) provides a cost input to the optimizer (420) based on a plurality of output parameters (220) of the power plant. The optimizer (420) determines an optimized operating parameter solution based on at least one of the income input and the cost input, and supplies the optimized operating parameter solution to the power plant.

  14. Hemiarthroplasty versus angle-stable locking compression plate osteosynthesis in the treatment of three- and four-part fractures of the proximal humerus in the elderly : design of a randomized controlled trial

    NARCIS (Netherlands)

    Verbeek, Paul A.; van den Akker-Scheek, Inge; Wendt, Klaus W.; Diercks, Ron L.

    2012-01-01

    Background: The optimal surgical management of dislocated three- and four-part fractures of the proximal humerus in elderly patients remains unclear. Most used techniques are hemiarthroplasty and angle-stable locking compression plate osteosynthesis. In the current literature there is no evidence av

  15. Receiver-exciter controller design

    Science.gov (United States)

    Jansma, P. A.

    1982-01-01

    A description of the general design of both the block 3 and block 4 receiver-exciter controllers for the Deep Space Network (DSN) Mark IV-A System is presented along with the design approach. The controllers are designed to enable the receiver-exciter subsystem (RCV) to be configured, calibrated, initialized and operated from a central location via high level instructions. The RECs are designed to be operated under the control of the DMC subsystem. The instructions are in the form of standard subsystem blocks (SSBs) received via the local area network (LAN). The centralized control provided by RECs and other DSCC controllers in Mark IV-A is intended to reduce DSN operations costs from the Mark III era.

  16. Application of a Computer-Assisted Navigation System (CANS) in the Delayed Treatment of Zygomatic Fractures: A Randomized Controlled Trial.

    Science.gov (United States)

    Gong, Xi; He, Yang; An, Jingang; Yang, Yao; Huang, Xiuling; Liu, Meng; Zhao, Yangyang; Zhang, Yi

    2017-07-01

    The delayed treatment of zygomatic complex (ZMC) fracture presents a difficult challenge to surgeons. The aim of this study was to compare the treatment effects of delayed surgery of ZMC fractures with and without a computer-assisted navigation system (CANS). In this observer-blinded single-site randomized clinical trial, patients with unilateral ZMC fracture were included and randomized 1:1 to delayed treatment with or without CANS. The primary outcome measurement was the absolute bilateral differences of the ZMC eminence and width based on computed tomographic (CT) measurements 48 to 72 hours after surgery. One hundred three patients with unilateral ZMC fracture without immediate treatment were enrolled, and 78 were randomized to each group. Postoperative CT measurements showed that the bilateral difference in ZMC eminence was significantly less for the navigation group than for the control group (1.24 vs 2.22 mm; P control group (P = .001). Photogrammetry showed that the average difference between the postoperative CT data and the preoperative design was smaller in the navigation group (1.30 vs 2.40 mm; P = .012). Use of CANS improved ZMC symmetry in patients with unilateral ZMC fracture who had delayed treatment by allowing for more accurate implementation of the preoperative plan. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Exposure to antiepileptic drugs and the risk of hip fracture: a case-control study

    DEFF Research Database (Denmark)

    Tsiropoulos, Ioannis; Andersen, Morten; Nymark, Tine

    2008-01-01

    PURPOSE: To investigate whether the use of antiepileptic drugs (AEDs) increases the risk of hip fracture. METHODS: We performed a case-control study using data from the Funen County (population 2004: 475,000) hip fracture register. Cases (n = 7,557) were all patients admitted to county hospitals ...

  18. A Novel Computer-Aided Approach for Parametric Investigation of Custom Design of Fracture Fixation Plates.

    Science.gov (United States)

    Chen, Xiaozhong; He, Kunjin; Chen, Zhengming

    2017-01-01

    The present study proposes an integrated computer-aided approach combining femur surface modeling, fracture evidence recover plate creation, and plate modification in order to conduct a parametric investigation of the design of custom plate for a specific patient. The study allows for improving the design efficiency of specific plates on the patients' femur parameters and the fracture information. Furthermore, the present approach will lead to exploration of plate modification and optimization. The three-dimensional (3D) surface model of a detailed femur and the corresponding fixation plate were represented with high-level feature parameters, and the shape of the specific plate was recursively modified in order to obtain the optimal plate for a specific patient. The proposed approach was tested and verified on a case study, and it could be helpful for orthopedic surgeons to design and modify the plate in order to fit the specific femur anatomy and the fracture information.

  19. A Novel Computer-Aided Approach for Parametric Investigation of Custom Design of Fracture Fixation Plates

    Science.gov (United States)

    2017-01-01

    The present study proposes an integrated computer-aided approach combining femur surface modeling, fracture evidence recover plate creation, and plate modification in order to conduct a parametric investigation of the design of custom plate for a specific patient. The study allows for improving the design efficiency of specific plates on the patients' femur parameters and the fracture information. Furthermore, the present approach will lead to exploration of plate modification and optimization. The three-dimensional (3D) surface model of a detailed femur and the corresponding fixation plate were represented with high-level feature parameters, and the shape of the specific plate was recursively modified in order to obtain the optimal plate for a specific patient. The proposed approach was tested and verified on a case study, and it could be helpful for orthopedic surgeons to design and modify the plate in order to fit the specific femur anatomy and the fracture information. PMID:28203270

  20. Controls on syndepositional fracture patterns, Devonian reef complexes, Canning Basin, Western Australia

    Science.gov (United States)

    Frost, Edmund L., III; Kerans, Charles

    2010-09-01

    Syndepositional fractures are an important feature of high-relief carbonate systems and exert a profound control on many facets of platform evolution and reservoir development. Based on data collected from the Canning Basin's Devonian reef complexes this study characterizes syndepositional fracture patterns as a function of variations in: lithofacies, depositional position, stratigraphic architecture, and mechanical stratigraphy. Fracture parameters, such as extension and fracture intensity, are documented to vary strongly as a function of lithofacies. The highest syndepositional extension values occurring in the microbial facies of the Famennian platform margin, with extension values three times higher than observed in equivalent Frasnian strata. Position along the depositional profile exerts a strong control on fracture patterns, with an approximate two-fold increase in syndepositional extension and fracture intensity typically observed from the platform interior to the platform margin. Syndepositional fracture intensity is shown to vary systematically with changes in platform-margin trajectory, with high fracture intensities observed in strongly progradational platforms and decreased fracture development in aggradational and retrogradational platforms. Evidence for the temporal evolution of the mechanical stratigraphy of the Devonian reef complexes is presented, with early-lithified strata effectively behaving as a single, large-scale (50-150 m) mechanical unit during syndepositional fracture development, while secondary fractures become increasingly affected by bed-scale (0.25-5 m) mechanical heterogeneity introduced by progressive diagenesis. The results presented here potentially provide a tool for predicting fracture characteristics (e.g., intensity, orientation, location, and vertical extent) from limited subsurface data and provide a method for characterizing syndepositional deformation in other systems.

  1. Fluid-dependent anisotropy and experimental measurements in synthetic porous rocks with controlled fracture parameters

    Science.gov (United States)

    Ding, Pinbo; Di, Bangrang; Wei, Jianxin; Li, Xiangyang; Deng, Yinghua

    2014-02-01

    In this study, we analyse the influence of fluid on P- and S-wave anisotropy in a fractured medium. Equivalent medium theories are used to describe the relationship between the fluid properties and the rock physics characteristics in fractured rocks, and P-wave and S-wave velocities and anisotropy are considered to be influenced by fluid saturation. However, these theoretical predictions require experimental measurement results for calibration. A new construction method was used to create synthetic rock samples with controlled fracture parameters. The new construction process provides synthetic rocks that have a more realistic mineral composition, porous structure, cementation and pressure sensitivity than samples used in previous research on fractured media. The synthetic rock samples contain fractures which have a controlled distribution, diameter, thickness and fracture density. In this study, the fracture diameter was about 4 mm, the thickness of fractures was about 0.06 mm, and the fracture density in the two fractured rock samples was about 3.45%. SEM images show well-defined penny-shaped fractures of 4 mm in length and 0.06 mm in width. The rock samples were saturated with air, water and oil, and P- and S-wave velocities were measured in an ultrasonic measurement system. The laboratory measurement results show that the P-wave anisotropy is strongly influenced by saturated fluid, and the P-wave anisotropy parameter, ɛ, has a much larger value in air saturation than in water and oil saturations. The S-wave anisotropy decreases when the samples are saturated with oil, which can be caused by high fluid viscosity. In the direction perpendicular to the fractures (the 0° direction), shear-wave splitting is negligible, and is similar to the blank sample without fractures, as expected. In the direction parallel to the fractures (the 90° direction) shear-wave splitting is significant. The fractured rock samples show significant P- and S-wave anisotropy caused by

  2. Controlling radiated emissions by design

    CERN Document Server

    Mardiguian, Michel

    2014-01-01

    The 3rd edition of Controlling Radiated Emissions by Design has been updated to reflect the latest changes in the field. New to this edition is material related to technical advances, specifically super-fast data rates on wire pairs, with no increase in RF interference. Throughout the book, details are given to control RF emissions using EMC design techniques. This book retains the step-by-step approach for incorporating EMC into every new design from the ground up. It describes the selection of quieter IC technologies, their implementation into a noise-free printed circuit layout, and the gathering of these into a low emissions package. Also included is how to design an I/O filter, along with connectors and cable considerations. All guidelines are supported throughout with comprehensive calculated examples. Design engineers, EMC specialists, and technicians will benefit from learning about the development of more efficient and economical control of emissions.

  3. Using Chemicals to Optimize Conformance Control in Fractured Reservoirs

    Energy Technology Data Exchange (ETDEWEB)

    Seright, Randall; Liang, Jenn-Tai; Schrader, Richard; Hagstrom II, John; Wang, Ying; Kumar, Anand; Wavrik, Kathryn

    2001-09-07

    The objectives of this project are: (1) to develop a capability to predict and optimize the ability of gels to reduce permeability to water more than that to oil or gas, (2) to develop procedures for optimizing blocking agent placement in wells where hydraulic fractures cause channeling problems, and (3) to develop procedures to optimize blocking agent placement in naturally fractured reservoirs. Work was directed at both injection wells and production wells and at vertical, horizontal, and highly deviated wells.

  4. Spacecraft Design Thermal Control Subsystem

    Science.gov (United States)

    Miyake, Robert N.

    2003-01-01

    This slide presentation reviews the functions of the thermal control subsystem engineers in the design of spacecraft. The goal of the thermal control subsystem that will be used in a spacecraft is to maintain the temperature of all spacecraft components, subsystems, and all the flight systems within specified limits for all flight modes from launch to the end of the mission. For most thermal control subsystems the mass, power and control and sensing systems must be kept below 10% of the total flight system resources. This means that the thermal control engineer is involved in all other flight systems designs. The two concepts of thermal control, passive and active are reviewed and the use of thermal modeling tools are explained. The testing of the thermal control is also reviewed.

  5. Physical processes that control droplet transport in rock fracture systems

    Science.gov (United States)

    Hay, Katrina Moran

    Aquifer recharge is generally driven by fluids that move from the Earths surface to groundwater through the unsaturated zone, also known as the vadose zone. When the vadose zone is fractured, fluids, which may include contaminants, can move through the fracture network as well as the porous matrix. Such a network of fractures can provide a more rapid path, thereby reducing contact time between the fluid and the matrix. Contact time allows for exchange of solutes between the fluid and the porous matrix, thus being able to quantify contact time is important. In addition, the behavior of fluids within a fracture network has been found to be very complex; large-scale models are yet not able to predict transport paths or flux rates. Because, small-scale flow phenomena can strongly influence the large-scale behavior of fluid movement through systems of fractures, it is important that small-scale dynamics be properly understood in order to improve our predictive capabilities in these complex systems. Relevant flow dynamics includes the impact of boundary conditions, fluid modes that evolve in time and space and transitions between modes. This thesis presents three investigations aimed at understanding the physical processes governing fluid movement in unsaturated fractures, with the ultimate goal of improving predictive relationships for fluid transport in rock fracture systems. These investigations include a theoretical analysis of the wetting of a rough surface, an experimental study of the dynamics of fluid droplets (or liquid bridges) moving in a single fracture and a theoretical analysis of the movement of a fluid droplet encountering a fracture intersection. Each investigation is motivated by environmental applications. Development of an analytical equation for the wetting of a rough surface is based on a balance between capillary forces and frictional resistive forces. The resulting equation predicts movement of the liquid invasion front driven solely by the

  6. The Influence of Material Type, Preparation Design, and Tooth Substrate on Fracture Resistance of Molar Onlays

    OpenAIRE

    Al Khalifah, Shahed Ali M.

    2016-01-01

    Tooth colored all ceramic restorations have been the treatment preference of many patients for esthetics and biocompatibility. This study aimed to test the fracture resistance of posterior ceramic onlays milled with computer-aided design and computer aided manufacturing (CAD/CAM) machines.The effects of material type, preparation design, and tooth substrate were evaluated using a full-block design. Ninety teeth were tested. Three different CAD/CAM ceramic onlay material types were included: a...

  7. Sedimentological and Stratigraphic Controls on Natural Fracture Distribution in Wajid Group, SW Saudi Arabia

    Science.gov (United States)

    Benaafi, Mohammed; Hariri, Mustafa; Abdullatif, Osman; Makkawi, Mohammed; Korvin, Gabor

    2016-04-01

    The Cambro-Permian Wajid Group, SW Saudi Arabia, is the main groundwater aquifer in Wadi Al-Dawasir and Najran areas. In addition, it has a reservoir potentiality for oil and natural gas in Rub' Al-Khali Basin. Wajid Group divided into four formations, ascending Dibsiyah, Sanamah, Khussyayan and Juwayl. They are mainly sandstone and exposed in an area extend from Wadi Al-Dawasir southward to Najran city and deposited within fluvial, shallow marine and glacial environments. This study aims to investigate the sedimentological and stratigraphic controls on the distribution of natural fractures within Wajid Group outcrops. A scanline sampling method was used to study the natural fracture network within Wajid Group outcrops, where the natural fractures were measured and characterized in 12 locations. Four regional natural fracture sets were observed with mean strikes of 050o, 075o, 345o, and 320o. Seven lithofacies characterized the Wajid Group at these locations and include fine-grained sandstone, coarse to pebbly sandstone, cross-bedded sandstone, massive sandstone, bioturbated sandstone, conglomerate sandstone, and conglomerate lithofacies. We found that the fine-grained and small scale cross-bedded sandstones lithofacies are characterized by high fracture intensity. In contrast, the coarse-grained sandstone and conglomerate lithofacies have low fracture intensity. Therefore, the relative fracture intensity and spacing of natural fractures within Wajid Group in the subsurface can be predicted by using the lithofacies and their depositional environments. In terms of stratigraphy, we found that the bed thickness and the stratigraphic architecture are the main controls on fractures intensity. The outcomes of this study can help to understand and predict the natural fracture distribution within the subsurface fractured sandstone hosting groundwater and hydrocarbon in Wajid and Rub' Al-Khali Basins. Hence, the finding of this study might help to explore and develop the

  8. Fractures in anisotropic media

    Science.gov (United States)

    Shao, Siyi

    Rocks may be composed of layers and contain fracture sets that cause the hydraulic, mechanical and seismic properties of a rock to be anisotropic. Coexisting fractures and layers in rock give rise to competing mechanisms of anisotropy. For example: (1) at low fracture stiffness, apparent shear-wave anisotropy induced by matrix layering can be masked or enhanced by the presence of a fracture, depending on the fracture orientation with respect to layering, and (2) compressional-wave guided modes generated by parallel fractures can also mask the presence of matrix layerings for particular fracture orientations and fracture specific stiffness. This report focuses on two anisotropic sources that are widely encountered in rock engineering: fractures (mechanical discontinuity) and matrix layering (impedance discontinuity), by investigating: (1) matrix property characterization, i.e., to determine elastic constants in anisotropic solids, (2) interface wave behavior in single-fractured anisotropic media, (3) compressional wave guided modes in parallel-fractured anisotropic media (single fracture orientation) and (4) the elastic response of orthogonal fracture networks. Elastic constants of a medium are required to understand and quantify wave propagation in anisotropic media but are affected by fractures and matrix properties. Experimental observations and analytical analysis demonstrate that behaviors of both fracture interface waves and compressional-wave guided modes for fractures in anisotropic media, are affected by fracture specific stiffness (controlled by external stresses), signal frequency and relative orientation between layerings in the matrix and fractures. A fractured layered medium exhibits: (1) fracture-dominated anisotropy when the fractures are weakly coupled; (2) isotropic behavior when fractures delay waves that are usually fast in a layered medium; and (3) matrix-dominated anisotropy when the fractures are closed and no longer delay the signal. The

  9. Controlling Subsurface Fractures and Fluid Flow: A Basic Research Agenda

    Energy Technology Data Exchange (ETDEWEB)

    Pyrak-Nolte, Laura J [Purdue Univ., West Lafayette, IN (United States); DePaolo, Donald J. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States); Pietraß, Tanja [USDOE Office of Science, Washington, DC (United States)

    2015-05-22

    From beneath the surface of the earth, we currently obtain about 80-percent of the energy our nation consumes each year. In the future we have the potential to generate billions of watts of electrical power from clean, green, geothermal energy sources. Our planet’s subsurface can also serve as a reservoir for storing energy produced from intermittent sources such as wind and solar, and it could provide safe, long-term storage of excess carbon dioxide, energy waste products and other hazardous materials. However, it is impossible to underestimate the complexities of the subsurface world. These complexities challenge our ability to acquire the scientific knowledge needed for the efficient and safe exploitation of its resources. To more effectively harness subsurface resources while mitigating the impacts of developing and using these resources, the U.S. Department of Energy established SubTER – the Subsurface Technology and Engineering RD&D Crosscut team. This DOE multi-office team engaged scientists and engineers from the national laboratories to assess and make recommendations for improving energy-related subsurface engineering. The SubTER team produced a plan with the overall objective of “adaptive control of subsurface fractures and fluid flow.”This plan revolved around four core technological pillars—Intelligent Wellbore Systems that sustain the integrity of the wellbore environment; Subsurface Stress and Induced Seismicity programs that guide and optimize sustainable energy strategies while reducing the risks associated with subsurface injections; Permeability Manipulation studies that improve methods of enhancing, impeding and eliminating fluid flow; and New Subsurface Signals that transform our ability to see into and characterize subsurface systems. The SubTER team developed an extensive R&D plan for advancing technologies within these four core pillars and also identified several areas where new technologies would require additional basic research

  10. Robust Control Design for Flight Control

    Science.gov (United States)

    1989-07-01

    to achieve desired performance over the full flight envelope when linear feedback is employed. Exact linearization methods [48] provide means for...designing nonlinear feedback laws which satisfy these requirements. However, exact linearization is not always compatible with control authority...specific situations. The most promising approaches appear to be those associated with methods of exact linearization . This procedure is based on some

  11. Influence of connector design on fracture probability of ceramic fixed-partial dentures.

    Science.gov (United States)

    Oh, W; Götzen, N; Anusavice, K J

    2002-09-01

    Fracture of ceramic fixed-partial dentures (FPDs) tends to occur in the connector area because of stress concentrations. The objective of this study was to test the hypothesis that the radius of curvature at the gingival embrasure of the FPD connector significantly affects the fracture resistance of three-unit FPDs. Two three-dimensional finite element models (FEMs), representing two FPD connector designs, were created in a manner corresponding to that described in a previous experimental study (Oh, 2002). We performed fractographic analysis and FEM analyses based on CARES (NASA) post-processing software to determine the crack initiation site as well as to predict the characteristic strength, the location of peak stress concentrations, and the risk-of-rupture intensities. A good correlation was found between the experimentally measured failure loads and those predicted by FEM simulation analyses. Fractography revealed fracture initiation at the gingival embrasure, which confirms the numerically predicted fracture initiation site. For the designs tested, the radius of curvature at the gingival embrasure strongly affects the fracture resistance of FPDs.

  12. Fatigue and fracture resistance of zirconia crowns prepared with different finish line designs

    NARCIS (Netherlands)

    Aboushelib, M.N.

    2012-01-01

    Purpose: The aim of this study was to evaluate the effect of finish line design on the fatigue, fracture resistance, and failure type of veneered zirconia restorations. Materials and Methods: A CAD/CAM system (Cercon) was used to prepare zirconia frameworks (0.5 mm thick) for a maxillary central

  13. The influence of zirconia coping designs on the fracture load of all-ceramic molar crowns.

    Science.gov (United States)

    Kokubo, Yuji; Tsumita, Mitsuyoshi; Kano, Takamitsu; Fukushima, Shunji

    2011-01-01

    This study investigated the influence of zirconia coping designs on the fracture load of all-ceramic crown. Four kinds of zirconia copings were designed (a: Conventional zirconia coping with flat occlusal surface: thickness of the each coping is 0.6 mm evenly, and at the cervical margin area, the coping is adjusted sharply so as to fit preparation margin, b: Conventional zirconia coping with shoulder collar of 1 mm: thickness of the each coping is 0.6 mm evenly, and there is a collar of 0.6 mm from the margin, c: Zirconia coping with following original cuspal configuration (concave): two inclined cusp planes, and at the cervical margin area, the coping is adjusted sharply so as to fit preparation margin, and d: Zirconia coping with supporting configuration on the occlusal area: supporting configuration against the occlusal force, and at the cervical margin area, the coping is adjusted sharply so as to fit preparation margin) and porcelain was fired. Vertical and lateral load were conducted until fracture. Coping design affected the fracture load; conventional uniform thickness coping design showed the lowest load (a), whereas cuspal configuration to perform even thickness of porcelain showed the highest fracture load both load directions (c).

  14. Fatigue and fracture resistance of zirconia crowns prepared with different finish line designs

    NARCIS (Netherlands)

    Aboushelib, M.N.

    2012-01-01

    Purpose: The aim of this study was to evaluate the effect of finish line design on the fatigue, fracture resistance, and failure type of veneered zirconia restorations. Materials and Methods: A CAD/CAM system (Cercon) was used to prepare zirconia frameworks (0.5 mm thick) for a maxillary central inc

  15. Robust control design with MATLAB

    CERN Document Server

    Gu, Da-Wei; Konstantinov, Mihail M

    2013-01-01

    Robust Control Design with MATLAB® (second edition) helps the student to learn how to use well-developed advanced robust control design methods in practical cases. To this end, several realistic control design examples from teaching-laboratory experiments, such as a two-wheeled, self-balancing robot, to complex systems like a flexible-link manipulator are given detailed presentation. All of these exercises are conducted using MATLAB® Robust Control Toolbox 3, Control System Toolbox and Simulink®. By sharing their experiences in industrial cases with minimum recourse to complicated theories and formulae, the authors convey essential ideas and useful insights into robust industrial control systems design using major H-infinity optimization and related methods allowing readers quickly to move on with their own challenges. The hands-on tutorial style of this text rests on an abundance of examples and features for the second edition: ·        rewritten and simplified presentation of theoretical and meth...

  16. The Effect of Cavity Design on Fracture Resistance and Failure Pattern in Monolithic Zirconia Partial Coverage Restorations - An In vitro Study

    Science.gov (United States)

    Harsha, Madhavareddy Sri; Babu, Mandava Ramesh; Leneena, Gudugunta; Krishna, Tejavath Sai; Divya, G

    2017-01-01

    Introduction Cavity preparations of posterior teeth have been frequently associated with decreased fracture strength of the teeth. Choosing the correct indirect restoration and the cavity design when restoring the posterior teeth i.e., premolars was difficult as it involves aesthetic, biomechanical and anatomical considerations. Aim To evaluate the fracture resistance and failure pattern of three different cavity designs restored with monolithic zirconia. Materials and Methods Human maxillary premolars atraumatically extracted for orthodontic reasons were chosen. A total of 40 teeth were selected and divided into four groups (n=10). Group I-Sound teeth (control with no preparation). Group II-MOD Inlay, Group III-Partial Onlay, Group IV-Complete Onlay. Restorations were fabricated with monolithic partially sintered zirconia CAD (SAGEMAX- NexxZr). All the 30 samples were cemented using Multilink Automix (Ivoclar) and subjected to fracture resistance testing using Universal Testing Machine (UTM) (Instron) with a steel ball of 3.5 mm diameter at crosshead speed of 0.5 mm/minute. Stereomicroscope was used to evaluate the modes of failure of the fractured specimen. Fracture resistance was tested using parametric one way ANOVA test, unpaired t-test and Tukey test. Fracture patterns were assessed using non-parametric Chi-square test. Results Group IV (Complete Onlay) presented highest fracture resistance and showed statistical significant difference. Group II (MOD Inlay) and Group III (Partial Onlay) showed significantly lower values than the Group I (Sound teeth). However, Groups I, II and III presented no significant difference from each other. Coming to the modes of failure, Group II (MOD Inlay) and Group III (Partial Onlay) presented mixed type of failures; Group IV (Complete Onlay) demonstrated 70% Type I failures. Conclusion Of the three cavity designs evaluated, Complete Onlay had shown a significant increase in the fracture resistance than the Sound teeth. PMID

  17. Effects of a training program after surgically treated ankle fracture: a prospective randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Ekdahl Charlotte S

    2009-09-01

    Full Text Available Abstract Background Despite conflicting results after surgically treated ankle fractures few studies have evaluated the effects of different types of training programs performed after plaster removal. The aim of this study was to evaluate the effects of a 12-week standardised but individually suited training program (training group versus usual care (control group after plaster removal in adults with surgically treated ankle fractures. Methods In total, 110 men and women, 18-64 years of age, with surgically treated ankle fracture were included and randomised to either a 12-week training program or to a control group. Six and twelve months after the injury the subjects were examined by the same physiotherapist who was blinded to the treatment group. The main outcome measure was the Olerud-Molander Ankle Score (OMAS which rates symptoms and subjectively scored function. Secondary outcome measures were: quality of life (SF-36, timed walking tests, ankle mobility tests, muscle strength tests and radiological status. Results 52 patients were randomised to the training group and 58 to the control group. Five patients dropped out before the six-month follow-up resulting in 50 patients in the training group and 55 in the control group. Nine patients dropped out between the six- and twelve-month follow-up resulting in 48 patients in both groups. When analysing the results in a mixed model analysis on repeated measures including interaction between age-group and treatment effect the training group demonstrated significantly improved results compared to the control group in subjects younger than 40 years of age regarding OMAS (p = 0.028, muscle strength in the plantar flexors (p = 0.029 and dorsiflexors (p = 0.030. Conclusion The results of this study suggest that when adjusting for interaction between age-group and treatment effect the training model employed in this study was superior to usual care in patients under the age of 40. However, as only three

  18. Design of the Face/Core Interface for Improved Fracture Resistance

    DEFF Research Database (Denmark)

    Lundsgaard-Larsen, Christian; Berggreen, Christian; Carlsson, Leif A.

    2008-01-01

    This study investigates the face/core fracture behavior of sandwich specimens with different designs. The traditional interface with a quadraxial mat directly adhered to the foam core is compared to interfaces where an additional mat with randomly oriented fibers is inserted between core and face....... The extra mat affects the crack propagation path in the sandwich specimen, and makes it more likely for the crack to propagate at or near the interface, instead of kinking into the laminate or core. Further, the extra mat acts as a source for fiber bridging, and hereby the fracture resistance is increased...... as bridging fibers shield the crack tip from the loading. Results show that the increase in fracture resistance due to fiber bridging is significant. Cohesive laws regarding cracking of sandwich interfaces are extracted....

  19. Topological design of all-ceramic dental bridges for enhancing fracture resistance.

    Science.gov (United States)

    Zhang, Zhongpu; Chen, Junning; Li, Eric; Li, Wei; Swain, Michael; Li, Qing

    2016-06-01

    Layered all-ceramic systems have been increasingly adopted in major dental prostheses. However, ceramics are inherently brittle, and they often subject to premature failure under high occlusion forces especially in the posterior region. This study aimed to develop mechanically sound novel topological designs for all-ceramic dental bridges by minimizing the fracture incidence under given loading conditions. A bi-directional evolutionary structural optimization (BESO) technique is implemented within the extended finite element method (XFEM) framework. Extended finite element method allows modeling crack initiation and propagation inside all-ceramic restoration systems. Following this, BESO searches the optimum distribution of two different ceramic materials, namely porcelain and zirconia, for minimizing fracture incidence. A performance index, as per a ratio of peak tensile stress to material strength, is used as a design objective. In this study, the novel XFEM based BESO topology optimization significantly improved structural strength by minimizing performance index for suppressing fracture incidence in the structures. As expected, the fracture resistance and factor of safety of fixed partial dentures structure increased upon redistributing zirconia and porcelain in the optimal topological configuration. Dental CAD/CAM systems and the emerging 3D printing technology were commercially available to facilitate implementation of such a computational design, exhibiting considerable potential for clinical application in the future. Copyright © 2015 John Wiley & Sons, Ltd.

  20. Report About the Design of External Fixator for Treatment of Pelvis and Acetabulum Fractures

    Directory of Open Access Journals (Sweden)

    Martin JANEČKA

    2012-06-01

    Full Text Available Main point in this contribution is the design of external fixators applied in traumatology and orthopaedics. These fixators can be used in the treatment of open and unstable (i.e. complicated fractures of pelvis and its acetabulum. Numerical modelling (i.e. Finite Element Method, together with CAD modelling, experiments, material engineering, and nanotechnology are presented as a support for developing of a new design of external fixators.

  1. Optimizing the design of vertical seismic profiling (VSP) for imaging fracture zones over hardrock basement geothermal environments

    Science.gov (United States)

    Reiser, Fabienne; Schmelzbach, Cedric; Maurer, Hansruedi; Greenhalgh, Stewart; Hellwig, Olaf

    2017-04-01

    A primary focus of geothermal seismic imaging is to map dipping faults and fracture zones that control rock permeability and fluid flow. Vertical seismic profiling (VSP) is therefore a most valuable means to image the immediate surroundings of an existing borehole to guide, for example, the placing of new boreholes to optimize production from known faults and fractures. We simulated 2D and 3D acoustic synthetic seismic data and processed it through to pre-stack depth migration to optimize VSP survey layouts for mapping moderately to steeply dipping fracture zones within possible basement geothermal reservoirs. Our VSP survey optimization procedure for sequentially selecting source locations to define the area where source points are best located for optimal imaging makes use of a cross-correlation statistic, by which a subset of migrated shot gathers is compared with a target or reference image from a comprehensive set of source gathers. In geothermal exploration at established sites, it is reasonable to assume that sufficient à priori information is available to construct such a target image. We generally obtained good results with a relatively small number of optimally chosen source positions distributed over an ideal source location area for different fracture zone scenarios (different dips, azimuths, and distances from the surveying borehole). Adding further sources outside the optimal source area did not necessarily improve the results, but rather resulted in image distortions. It was found that fracture zones located at borehole-receiver depths and laterally offset from the borehole by 300 m can be imaged reliably for a range of the different dips, but more source positions and large offsets between sources and the borehole are required for imaging steeply dipping interfaces. When such features cross-cut the borehole, they are particularly difficult to image. For fracture zones with different azimuths, 3D effects are observed. Far offset source positions

  2. Major factors controlling fracture development in the Middle Permian Lucaogou Formation tight oil reservoir, Junggar Basin, NW China

    Science.gov (United States)

    Zhang, Chen; Zhu, Deyu; Luo, Qun; Liu, Luofu; Liu, Dongdong; Yan, Lin; Zhang, Yunzhao

    2017-09-01

    Natural fractures in seven wells from the Middle Permian Lucaogou Formation in the Junggar Basin were evaluated in light of regional structural evolution, tight reservoir geochemistry (including TOC and mineral composition), carbon and oxygen isotopes of calcite-filled fractures, and acoustic emission (AE). Factors controlling the development of natural fractures were analyzed using qualitative and/or semi-quantitative techniques, with results showing that tectonic factors are the primary control on fracture development in the Middle Permian Lucaogou Formation of the Junggar Basin. Analyses of calcite, dolomite, and TOC show positive correlations with the number of fractures, while deltaic lithofacies appear to be the most favorable for fracture development. Mineral content was found to be a major control on tectonic fracture development, while TOC content and sedimentary facies mainly control bedding fractures. Carbon and oxygen isotopes vary greatly in calcite-filled fractures (δ13C ranges from 0.87‰ to 7.98‰, while δ18O ranges from -12.63‰ to -5.65‰), indicating that fracture development increases with intensified tectonic activity or enhanced diagenetic alteration. By analyzing the cross-cutting relationships of fractures in core, as well as four Kaiser Effect points in the acoustic emission curve, we observed four stages of tectonic fracture development. First-stage fractures are extensional, and were generated in the late Triassic, with calcite fracture fills formed between 36.51 °C and 56.89 °C. Second-stage fractures are shear fractures caused by extrusion stress from the southwest to the northeast, generated by the rapid uplift of the Tianshan in the Middle and Late Jurassic; calcite fracture fills formed between 62.91 °C and 69.88 °C. Third-stage fractures are NNW-trending shear fractures that resulted from north-south extrusion and thrusting in a foreland depression along the front of the Early Cretaceous Bogda Mountains. Calcite fracture

  3. Comparison of Chamfer and Deep Chamfer Preparation Designs on the Fracture Resistance of Zirconia Core Restorations

    Directory of Open Access Journals (Sweden)

    Ezatollah Jalalian

    2011-06-01

    Full Text Available Background and aims. One of the major problems of all-ceramic restorations is their probable fracture under occlusal force. The aim of the present in vitro study was to compare the effect of two marginal designs (chamfer and deep chamfer on the fracture resistance of all-ceramic restorations, CERCON. Materials and methods. This in vitro study was carried out with single-blind experimental technique. One stainless steel die with 50’ chamfer finish line design (0.8 mm deep was prepared using a milling machine. Ten epoxy resin dies were prepared. The same die was retrieved and 50' chamfer was converted into a deep chamfer design (1 mm. Again ten epoxy resin dies were prepared from the deep chamfer die. Zirconia cores with 0.4 mm thickness and 35 µm cement space were fabricated on the epoxy resin dies (10 chamfer and 10 deep chamfer samples. The zirconia cores were cemented on the epoxy resin dies and underwent a fracture test with a universal testing machine and the samples were investigated from the point of view of the origin of the failure. Results. The mean values of fracture resistance for deep chamfer and chamfer samples were 1426.10±182.60 and 991.75±112.00 N, respectively. Student’s t-test revealed statistically significant differences between the groups. Conclusion. The results indicated a relationship between the marginal design of zirconia cores and their fracture resistance. A deep chamfer margin improved the biomechanical performance of posterior single zirconia crown restorations, which might be attributed to greater thickness and rounded internal angles in deep chamfer margins.

  4. Aerodynamic design via control theory

    Science.gov (United States)

    Jameson, Antony

    1988-01-01

    The question of how to modify aerodynamic design in order to improve performance is addressed. Representative examples are given to demonstrate the computational feasibility of using control theory for such a purpose. An introduction and historical survey of the subject is included.

  5. Consistent Design of Dependable Control Systems

    DEFF Research Database (Denmark)

    Blanke, M.

    1996-01-01

    Design of fault handling in control systems is discussed, and a method for consistent design is presented.......Design of fault handling in control systems is discussed, and a method for consistent design is presented....

  6. Design of reconfigurable logic controllers

    CERN Document Server

    Bukowiec, Arkadiusz; Doligalski, Michał; Tkacz, Jacek

    2016-01-01

    This book presents the original concepts and modern techniques for specification, synthesis, optimisation and implementation of parallel logical control devices. It deals with essential problems of reconfigurable control systems like dependability, modularity and portability. Reconfigurable systems require a wider variety of design and verification options than the application-specific integrated circuits. The book presents a comprehensive selection of possible design techniques. The diversity of the modelling approaches covers Petri nets, state machines and activity diagrams. The preferences of the presented optimization and synthesis methods are not limited to increasing of the efficiency of resource use. One of the biggest advantages of the presented methods is the platform independence, the FPGA devices and single board computers are some of the examples of possible platforms. These issues and problems are illustrated with practical cases of complete control systems. If you expect a new look at the recon...

  7. Distinct element modelling of fracture plan control in continuum and jointed rock mass in presplitting method of surface mining

    Institute of Scientific and Technical Information of China (English)

    Sharafisafa Mansour; Aliabadian Zeinab; Alizadeh Rezvan; Mortazavi Ali

    2014-01-01

    Controlled blasting techniques are used to control overbreak and to aid in the stability of the remaining rock formation. Presplitting is one of the most common methods which is used in many open pit mining and surface blast design. The purpose of presplitting is to form a fracture plane across which the radial cracks from the production blast cannot travel. The purpose of this study is to investigate of effect of pre-splitting on the generation of a smooth wall in continuum and jointed rock mass. The 2D distinct element code was used to simulate the presplitting in a rock slope. The blast load history as a function of time was applied to the inner wall of each blasthole. Important parameters that were considered in the analysis were stress tensor and fracturing pattern. The blast loading magnitude and blasthole spacing and jointing pattern were found to be very significant in the final results.

  8. Improving community ambulation after hip fracture: protocol for a randomised, controlled trial

    Science.gov (United States)

    Orwig, D; Mangione, KK; Baumgarten, M; Terrin, M; Fortinsky, R; Kenny, AM; Gruber-Baldini, AL; Beamer, B; Tosteson, ANA; Shardell, M; Magder, L; Binder, E; Koval, K; Resnick, B; Craik, RL; Magaziner, J

    2017-01-01

    Introduction After a hip fracture in older persons, significant disability often remains; dependency in functional activities commonly persists beyond 3 months after surgery. Endurance, dynamic balance, quadriceps strength, and function are compromised, and contribute to an inability to walk independently in the community. In the United States, people aged 65 years and older are eligible to receive Medicare funding for physiotherapy for a limited time after a hip fracture. A goal of outpatient physiotherapy is independent and safe household ambulation 2 to 3 months after surgery. Current Medicare-reimbursed post-hip-fracture rehabilitation fails to return many patients to pre-fracture levels of function. Interventions delivered in the home after usual hip fracture physiotherapy has ended could promote higher levels of functional independence in these frail and older adult patients. Primary objective To evaluate the effect of a specific multicomponent physiotherapy intervention (PUSH), compared with a non-specific multi-component control physiotherapy intervention (PULSE), on the ability to ambulate independently in the community 16 weeks after randomisation. Design Parallel, two-group randomised multicentre trial of 210 older adults with a hip fracture assessed at baseline and 16 weeks after randomisation, and at 40 weeks after randomisation for a subset of approximately 150 participants. Participants and setting A total of 210 hip fracture patients are being enrolled at three clinical sites and randomised up to 26 weeks after admission. Study inclusion criteria are: closed, non-pathologic, minimal trauma hip fracture with surgical fixation; aged ≥ 60 years at the time of randomisation; community residing at the time of fracture and randomisation; ambulating without human assistance 2 months prior to fracture; and being unable to walk at least 300 m in 6 minutes at baseline. Participants are ineligible if the interventions are deemed to be unsafe or unfeasible

  9. Directional hydraulic fracturing to control hard-roof rockburst in coal mines

    Institute of Scientific and Technical Information of China (English)

    Fan Jun; Dou Linming; He Hu; Du Taotao; Zhang Shibin; Gui Bing; Sun Xinglin

    2012-01-01

    Hard roof is the main factor that induces rock-burst.In view of the present obvious weakness of control measures for hard roof rockburst in domestic collieries,the mechanism and field application of directional hydraulic fracturing technology for rock-burst prevention have been investigated in this paper using theoretical analysis and numerical simulation.The results show that the weighting span of the main roof and the released kinetic energy as well as the total elastic energy decreased greatly after the directional fracturing of hard roof with the mining progression,thereby reducing the rockburst hazard degree to coal body.The directional hydraulic fracturing technology was carried out in 6305 working face of Jisan Coal Mine to prevent rockburst.Field practices have proved that this technology is much simpler and safer to operate with better prevention effect compared with blasting.By optimizing the operation procedures and developing a new technology of automated high-pressure delivery pipe,the maximum fracturing radius now reaches more than 9 m and the borehole depth exceeds 20 m.Additionally,drilling cutting method was applied to monitor the stress of the coal mass before and after the fracturing,and the drill cuttings dropped significantly which indicates that the burst prevention effect of directional hydraulic fracturing technology is very remarkable.The research results of this paper have laid a theoretical and practical foundation for the widespread application of the directional hydraulic fracturing technology in China.

  10. Internal plate fixation versus plaster in displaced complete articular distal radius fractures, a randomised controlled trial.

    Science.gov (United States)

    Mulders, Marjolein A M; Walenkamp, Monique M J; Goslings, J Carel; Schep, Niels W L

    2016-02-09

    Of all distal radius fractures, 25 % are complete articular fractures (AO/OTA type C fractures). Two thirds of those fractures are displaced and require reduction. According to several International Guidelines, adequately reduced intra-articular distal radius fractures are best treated non-operatively with plaster immobilisation, while surgical fixation is suggested only when the articular step exceeds 2 mm after reduction. However, these recommendations are based on studies that did not differentiate between intra- and extra-articular distal radius fractures. Thus, no clear consensus about the best treatment for patients with displaced intra-articular distal radius fractures can be reached. Despite the lack of evidence, an increase in internal fixation of intra-articular distal radius fractures has been observed over the last decade. The aim of this study is to determine the difference in functional outcome following open reduction and plate fixation compared with non-operative treatment with closed reduction and plaster immobilisation in patients with a displaced intra articular distal radius fracture. This multicentre randomised controlled trial will randomise between open reduction and internal plate fixation (intervention group) and closed reduction and plaster immobilisation (control group). All consecutive adult patients from 18 to 65 years with a displaced intra-articular distal radius fracture (AO/OTA type C), which has been adequately reduced at the Emergency Department according to the Dutch National Guidelines, are eligible for inclusion in this study. The primary outcome is function and pain of the wrist assessed with the Patient-Rated Wrist Evaluation score (PRWE). Secondary outcomes are the Disability of the Arm, Shoulder and Hand score (DASH), pain, quality of life (SF-36), range of motion, grip strength, radiological parameters, complications, crossovers and cost-effectiveness of both treatments. A total of 90 patients will be included in this

  11. [Distortion and vertical fracture of the root: effect produced by condenser design].

    Science.gov (United States)

    Dang, D A; Walton, R E

    1990-01-01

    The incidence of vertical root fractures and the amount of root distortion created during lateral condensation of gutta-percha with either D11 spreaders or B-finger pluggers were evaluated in vitro. Fifty-five extracted human, single-rooted teeth were instrumented using the step-back flare technique. Ten teeth served as positive controls (obturation to the point of fracture) and five teeth as negative controls (prepared but not obtured). Strain gauges were attached to the root surfaces. In the experimental group, 20 teeth were obturated using a D11 spreader and 20 with a B-finger plugger. Recordings were made of root distortion (expansion) created during obturation. Then, after sectioning the teeth, root surfaces of obturated samples were examined for fractures under the scanning electron microscope. Only the more tapered spreader, the D11, produces vertical root fractures, although very few in number. Also, the D11 spreader caused greater root distortion than did the B-finger plugger.

  12. Lumbar lordosis and pars interarticularis fractures: a case-control study.

    Science.gov (United States)

    Bugg, William G; Lewis, Mark; Juette, Arne; Cahir, John G; Toms, Andoni P

    2012-07-01

    The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63 years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9° (SD = 6.5°) in the pars interarticularis fracture group, and 30.1° (SD = 6.4°) in the control group. The difference between the two groups was significant (mean difference 6.8°, Student's t test: P lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis.

  13. Practical design control implementation for medical devices

    CERN Document Server

    Justiniano, Jose

    2003-01-01

    Bringing together the concepts of design control and reliability engineering, this book is a must for medical device manufacturers. It helps them meet the challenge of designing and developing products that meet or exceed customer expectations and also meet regulatory requirements. Part One covers motivation for design control and validation, design control requirements, process validation and design transfer, quality system for design control, and measuring design control program effectiveness. Part Two discusses risk analysis and FMEA, designing-in reliability, reliability and design verific

  14. Pilot case-control investigation of risk factors for hip fractures in the urban Indian population

    Directory of Open Access Journals (Sweden)

    Malhotra Nidhi

    2010-03-01

    Full Text Available Abstract Background Despite the reported high prevalence of osteoporosis in India, there have been no previous studies examining the risk factors for hip fracture in the Indian population. Methods We carried out a case control investigation comprising 100 case subjects (57 women and 43 men admitted with a first hip fracture into one of three hospitals across New Delhi. The 100 controls were age and sex matched subjects who were either healthy visitors not related to the case patients or hospital staff. Information from all subjects was obtained through a questionnaire based interview. Results There was a significant increase in the number of cases of hip fracture with increasing age. There were significantly more women (57% than men (43%. Univariate analysis identified protective effects for increased activity, exercise, calcium and vitamin supplements, almonds, fish, paneer (cottage cheese, curd (plain yogurt, and milk. However, tea and other caffeinated beverages were significant risk factors. In women, hormone/estrogen therapy appeared to have a marginal protective effect. For all cases, decreased agility, visual impairment, long term medications, chronic illnesses increased the risk of hip fracture. The multivariate analysis confirmed a protective effect of increased activity and also showed a decrease in hip fracture risk with increasing body mass index (odds ratio (OR 0.024, 95% confidence interval (CI 0.006-0.10 & OR 0.81, 95% CI 0.68-0.97 respectively. Individuals who take calcium supplements have a decreased risk of hip fracture (OR 0.076; CI 0.017-0.340, as do individuals who eat fish (OR 0.094; CI 0.020-0.431, and those who eat paneer (OR 0.152; 0.031-0.741. Tea drinkers have a higher risk of hip fracture (OR 22.8; 95% CI 3.73-139.43. Difficulty in getting up from a chair also appears to be an important risk factor for hip fractures (OR 14.53; 95% CI 3.86-54.23. Conclusions In the urban Indian population, dietary calcium, vitamin D

  15. High bone mineral density and fracture risk in type 2 diabetes as skeletal complications of inadequate glucose control: The Rotterdam study

    NARCIS (Netherlands)

    L. Oei (Ling); M.C. Zillikens (Carola); A. Dehghan (Abbas); G.H.S. Buitendijk (Gabrielle); M.C. Castaño Betancourt (Martha); K. Estrada Gil (Karol); L. Stolk (Lisette); E.H.G. Oei (Edwin); J.B.J. van Meurs (Joyce); J.A.M.J.L. Janssen (Joseph); A. Hofman (Albert); J.P.T.M. van Leeuwen (Hans); J.C.M. Witteman (Jacqueline); H.A.P. Pols (Huib); A.G. Uitterlinden (André); C.C.W. Klaver (Caroline); O.H. Franco (Oscar); F. Rivadeneira Ramirez (Fernando)

    2013-01-01

    textabstractOBJECTIVE - Individuals with type 2 diabetes have increased fracture risk despite higher bone mineral density (BMD). Our aim was to examine the influence of glucose control on skeletal complications. RESEARCH DESIGN AND METHODS - Data of 4,135 participants of the Rotterdam Study, a prosp

  16. Method to calculate fatigue fracture life of control fissure in perilous rock

    Institute of Scientific and Technical Information of China (English)

    CHEN Hong-kai; TANG Hong-mei

    2007-01-01

    Rupture and safety of perilous rock are dominated by control fissure behind perilous rock block. Based on model-Ⅰ and model-Ⅱ stress strength factors of control fissure under acting of weight of perilous rock, water pressure in control fissure and earthquake forces, method to calculate critical linking length of control fissure is established. Take water pressure in control fissure as a variable periodic load, and abide by P-M criterion, when control fissure is filled with water, establish the method to calculate fatigue fracture life of control fissure in critical status by contributing value of stress strength factor stemming from water pressure of control fissure in Paris's fatigue equation. Further, parameters(C and m)of sandstone with quartz and feldspar in the area of the Three Gorges Reservoir of China are obtained by fatigue fracture testing.

  17. High Prevalence of Sarcopenia in Korean Patients after Hip Fracture: a Case-Control Study.

    Science.gov (United States)

    Yoo, Jun Il; Ha, Yong Chan; Kwon, Hyeok Bin; Lee, Young Kyun; Koo, Kyung Hoi; Yoo, Moon Jib

    2016-09-01

    Sarcopenia-related falls and fractures are increasing worldwide due to the aging population. The purpose of this study was to 1) evaluate anthropometric characteristics related to hip fracture in Korean patients, 2) investigate sarcopenia prevalence in hip fracture (HF) and non-hip fracture (NF) groups, and 3) investigate the correlation between sarcopenia and osteoporosis. This case-control study examined 359 HF and 1,614 NF normal populations using Korea National Health and Nutrition Examination Survey data. We performed whole-body dual energy X-ray absorptiometry to analyze body composition using the skeletal muscle mass index (SMI: lean mass/height²) and bone mineral density (BMD). In the HF group, using the AWGS definition, the prevalence of sarcopenia in women and men was 44.3% and 68.2%, respectively; in the NF group, it was 7.1% and 16.1%, respectively. Lower appendicular SMI (P sarcopenia (P sarcopenia (OR = 6.52; 95% CI = 4.67-9.09), age (OR = 1.15; 95% CI = 1.13-1.17), and osteoporosis (OR = 1.87; 95% CI = 1.35-2.58) were associated with the occurrence of a hip fracture. This study showed a higher prevalence of sarcopenia in patients with hip fractures compared with a normal population, and higher prevalence of sarcopenia in men.

  18. Predicting Future Hip Fractures on Routine Abdominal CT Using Opportunistic Osteoporosis Screening Measures: A Matched Case-Control Study.

    Science.gov (United States)

    Lee, Scott J; Anderson, Paul A; Pickhardt, Perry J

    2017-08-01

    Hip fracture is a major consequence of low bone mineral density, which is treatable but underdiagnosed. The purpose of this case-control study is to determine whether lumbar vertebral trabecular attenuation, vertebral compression fractures, and femoral neck T scores readily derived from abdominopelvic CT scans obtained for various indications are associated with future hip fragility fracture. A cohort of 204 patients with hip fracture (130 women and 74 men; mean age, 74.3 years) who had undergone abdominopelvic CT before fracture occurred (mean interval, 24.8 months) was compared with an age- and sex-matched control cohort without hip fracture. L1 trabecular attenuation, vertebral compression fractures of grades 2 and 3, and femoral neck T scores derived from asynchronous quantitative CT were recorded. The presence of one or more clinical risk factor for fracture was also recorded. Multivariate logistic regression models were used to determine the association of each measurement with the occurrence of hip fracture. The mean L1 trabecular attenuation value, the presence of one or more vertebral compression fracture, and CT-derived femoral neck T scores were all significantly different in patients with hip fracture versus control subjects (p hip fracture outcome after adjustments were made for age, sex, and the presence of one or more clinical risk factor. L1 trabecular attenuation and CT-derived femoral neck T scores showed moderate accuracy in differentiating case and control patients (AUC, 0.70 and 0.78, respectively). L1 trabecular attenuation, CT-derived femoral neck T scores, and the presence of at least one vertebral compression fracture on CT are all associated with future hip fragility fracture in adults undergoing routine abdominopelvic CT for a variety of conditions.

  19. Case-control study on factors associated with crown fractures in the primary dentition

    OpenAIRE

    2015-01-01

    The purpose of the present study was to identify the factors associated with dental trauma in preschool children. This case-control study was nested in a population-based cross-sectional study involving a random sample of 301 children one to five years of age in the city of Diamantina, Brazil. The case group was made up of children with at least one fractured deciduous tooth, and the control group was made up of children with no deciduous tooth fracture. The two groups were matched for age in...

  20. Experimental Investigation on the Basic Law of Hydraulic Fracturing After Water Pressure Control Blasting

    Science.gov (United States)

    Huang, Bingxiang; Li, Pengfeng; Ma, Jian; Chen, Shuliang

    2014-07-01

    Because of the advantages of integrating water pressure blasting and hydraulic fracturing, the use of hydraulic fracturing after water pressure control blasting is a method that is used to fully transform the structure of a coal-rock mass by increasing the number and range of hydraulic cracks. An experiment to study hydraulic fracturing after water pressure blasting on cement mortar samples (300 × 300 × 300 mm3) was conducted using a large-sized true triaxial hydraulic fracturing experimental system. A traditional hydraulic fracturing experiment was also performed for comparison. The experimental results show that water pressure blasting produces many blasting cracks, and follow-up hydraulic fracturing forces blasting cracks to propagate further and to form numerous multidirectional hydraulic cracks. Four macroscopic main hydraulic cracks in total were noted along the borehole axial and radial directions on the sample surfaces. Axial and radial main failure planes induced by macroscopic main hydraulic cracks split the sample into three big parts. Meanwhile, numerous local hydraulic cracks were formed on the main failure planes, in different directions and of different types. Local hydraulic cracks are mainly of three types: local hydraulic crack bands, local branched hydraulic cracks, and axial layered cracks. Because local hydraulic cracks produce multiple local layered failure planes and lamellar ruptures inside the sample, the integrity of the sample decreases greatly. The formation and propagation process of many multidirectional hydraulic cracks is affected by a combination of water pressure blasting, water pressure of fracturing, and the stress field of the surrounding rock. To a certain degree, the stress field of surrounding rock guides the formation and propagation process of the blasting crack and the follow-up hydraulic crack. Following hydraulic fracturing that has been conducted after water pressure blasting, the integrity of the sample is found to

  1. Medication use before and after hip fracture: a population-based cohort and case-control study.

    Science.gov (United States)

    Rossini, Maurizio; Viapiana, Ombretta; Adami, Silvano; Idolazzi, Luca; Buda, Stefano; Veronesi, Chiara; Degli Esposti, Luca; Gatti, Davide

    2014-07-01

    Osteoporosis, together with age, is the main risk factor for hip fracture, the incidence of which has also been associated with an increased risk of falling or co-morbidities and related pharmacological treatments. The aim of this study was to investigate changes in concomitant pharmacological treatments prescribed before and after hip fracture in elderly patients compared with treatments prescribed to a matched cohort of subjects without hospitalisation for fractures. Data relating to the study population were extracted from a large population-based administrative database of the Italian National Health Authorities. A retrospective analysis was conducted involving female patients (6,431) aged ≥65 years and hospitalised for a hip fracture. The control group comprised age-matched subjects (38,586) not hospitalised for fracture. Changes in drug prescriptions 1 year before and 1 year after hip fracture and differences versus controls were compared. Prior to the fracture, patients were taking more anti-Parkinson medications, antidepressants, medications for chronic obstructive pulmonary disease (COPD), bisphosphonates and calcium-vitamin D supplements, although the intake of the routinely monitored drug classes was significantly infrequent. Polypharmacy was less frequent in fractured women before fracture than in controls (22 vs. 25 %, respectively; P globally less common than in controls. Hip fracture is associated with a significant increase in drug use, suggesting a global deterioration of health conditions.

  2. Effects of a Rehabilitation Program on Perceived Environmental Barriers in Older Patients Recovering from Hip Fracture: A Randomized Controlled Trial

    Directory of Open Access Journals (Sweden)

    Erja Portegijs

    2013-01-01

    Full Text Available Objectives. To study effects of a one-year multicomponent intervention on perceived environmental barriers in hip fracture patients. Design. Randomized controlled trial of a 12-month home-based rehabilitation aiming to improve mobility and function (ISRCTN53680197; secondary analyses. Subjects. Community-dwelling hip fracture patients on average 70 days after trauma (n=81. Methods. Assessments at baseline, 3, 6, and 12 months later included perceived entrance-related barriers (e.g., indoor/outdoor stairs, lighting, floor surfaces, and storage for mobility devices and perceived barriers in the outdoor environment (poor street condition, hilly terrain, long-distances, and lack of resting places. Sum scores for entrance-related and outdoor barriers were analyzed using general estimating equation models. Results. At baseline, 48% and 37% of the patients perceived at least one entrance-related barrier, and 62% and 60% perceived at least one outdoor barrier in the intervention and control group, respectively. Over time, (P=0.003 the number of entrance-related barriers decreased in both groups (group P=0.395; interaction P=0.571. For outdoor barriers, time (P=0.199, group (P=0.911, and interaction effect (P=0.430 were not significant. Conclusion. Our intervention had no additional benefit over standard care in hip fracture patients. Further study is warranted to determine whether perceived environmental barriers can be reduced by interventions targeted at the older individual. This trial is registered with ISRCTN53680197.

  3. Design of Controllers for Liquid Level Control

    OpenAIRE

    Augustin Simon,; Elizabeth Varghese

    2015-01-01

    The liquid level control system is commonly used in many process control applications. The aim of the process is to keep the liquid level in the tank at the desired value. The conventional proportional-integral-derivative (PID) controller is simple, reliable and eliminates the error rate but it cannot handle complex problems. Fuzzy logic controllers are rule based systems which simulates human behavior of the process. The fuzzy controller is combined with the PID controller and th...

  4. Experimental validation of microseismic emissions from a controlled hydraulic fracture in a synthetic layered medium

    Science.gov (United States)

    Roundtree, Russell

    A controlled hydraulic fracture experiment was performed on two medium sized (11" x 11" x 15") synthetic layered blocks of low permeability, low porosity Lyons sandstone sandwiched between cement. The purpose of the research was to better understand and characterize the fracture evolution as the fracture tip impinged upon the layer boundaries between the well bonded layers. It is also one of the first documented uses of passive microseismic used in a laboratory environment to characterize hydraulic fracturing. A relatively low viscosity fluid of 1000 centipoise, compared to properly scaled previous work (Casas 2005, and Athavale 2007), was pumped at a constant rate of 10 mL/minute through a steel cased hole landed and isolated in the sandstone layer. Efforts were made to contain the hydraulic fracture within the confines of the rock specimen to retain the created hydraulic fracture geometry. Two identical samples and treatment schedules were created and differed only in the monitoring system used to characterize the microseismic activity during the fracture treatment. The first block had eight embedded P-wave transducers placed in the sandstone layer to record the passive microseismic emissions and localize the location and time of the acoustic event. The second block had six compressional wave transducers and twelve shear wave transducers embedded in the sandstone layer of the block. The intention was to record and process the seismic data using conventional P-wave to S-wave difference timing techniques well known in industry. While this goal ultimately not possible due to the geometry of the receiver placements and the limitations of the Vallene acquisition processing software, the data received and the events localized from the 18 transducer test were of much higher numbers and quality than on the eight transducer test. This experiment proved conclusively that passive seismic emission recording can yield positive results in the laboratory. Just as in the field

  5. Design-Optimization and Material Selection for a Proximal Radius Fracture-Fixation Implant

    Science.gov (United States)

    Grujicic, M.; Xie, X.; Arakere, G.; Grujicic, A.; Wagner, D. W.; Vallejo, A.

    2010-11-01

    The problem of optimal size, shape, and placement of a proximal radius-fracture fixation-plate is addressed computationally using a combined finite-element/design-optimization procedure. To expand the set of physiological loading conditions experienced by the implant during normal everyday activities of the patient, beyond those typically covered by the pre-clinical implant-evaluation testing procedures, the case of a wheel-chair push exertion is considered. Toward that end, a musculoskeletal multi-body inverse-dynamics analysis is carried out of a human propelling a wheelchair. The results obtained are used as input to a finite-element structural analysis for evaluation of the maximum stress and fatigue life of the parametrically defined implant design. While optimizing the design of the radius-fracture fixation-plate, realistic functional requirements pertaining to the attainment of the required level of the devise safety factor and longevity/lifecycle were considered. It is argued that the type of analyses employed in the present work should be: (a) used to complement the standard experimental pre-clinical implant-evaluation tests (the tests which normally include a limited number of daily-living physiological loading conditions and which rely on single pass/fail outcomes/decisions with respect to a set of lower-bound implant-performance criteria) and (b) integrated early in the implant design and material/manufacturing-route selection process.

  6. A maximum likelihood estimator for bedrock fracture transmissivities and its application to the analysis and design of borehole hydraulic tests

    Science.gov (United States)

    West, Anthony C. F.; Novakowski, Kent S.; Gazor, Saeed

    2006-06-01

    We propose a new method to estimate the transmissivities of bedrock fractures from transmissivities measured in intervals of fixed length along a borehole. We define the scale of a fracture set by the inverse of the density of the Poisson point process assumed to represent their locations along the borehole wall, and we assume a lognormal distribution for their transmissivities. The parameters of the latter distribution are estimated by maximizing the likelihood of a left-censored subset of the data where the degree of censorship depends on the scale of the considered fracture set. We applied the method to sets of interval transmissivities simulated by summing random fracture transmissivities drawn from a specified population. We found the estimated distributions compared well to the transmissivity distributions of similarly scaled subsets of the most transmissive fractures from among the specified population. Estimation accuracy was most sensitive to the variance in the transmissivities of the fracture population. Using the proposed method, we estimated the transmissivities of fractures at increasing scale from hydraulic test data collected at a fixed scale in Smithville, Ontario, Canada. This is an important advancement since the resultant curves of transmissivity parameters versus fracture set scale would only previously have been obtainable from hydraulic tests conducted with increasing test interval length and with degrading equipment precision. Finally, on the basis of the properties of the proposed method, we propose guidelines for the design of fixed interval length hydraulic testing programs that require minimal prior knowledge of the rock.

  7. Open reduction versus endoscopically controlled reconstruction of orbital floor fractures: a retrospective analysis.

    NARCIS (Netherlands)

    Hundepool, A.C.; Willemsen, M.A.A.P.; Koudstaal, M.J.; Wal, K.G.H. van der

    2012-01-01

    The aim of this study was to compare the postoperative results of open reduction versus endoscopically controlled reconstructions of orbital floor fractures. The medical records of 83 patients, treated between January 2000 and December 2008, were reviewed for enophthalmos, diplopia and complications

  8. Ankylosing spondylitis confers substantially increased risk of clinical spine fractures : a nationwide case-control study

    NARCIS (Netherlands)

    Prieto-Alhambra, D; Muñoz-Ortego, J; De Vries, F; Vosse, D; Arden, N K; Bowness, P; Cooper, C; Diez-Perez, A; Vestergaard, P

    2015-01-01

    UNLABELLED: Ankylosing spondylitis (AS) leads to osteopenia/osteoporosis and spine rigidity. We conducted a case-control study and found that AS-affected patients have a 5-fold and 50 % increased risk of clinical spine and all clinical fractures, respectively. Excess risk of both is highest in the f

  9. Open reduction and internal fixation of proximal humerus fractures.

    Science.gov (United States)

    Drosdowech, Darren S; Faber, Kenneth J; Athwal, George S

    2008-10-01

    Open reduction of proximal humeral fractures has the advantage of providing direct control over each fracture fragment and permitting anatomic reduction and fixation with advanced devices. Modern fixed-angle locking plates designed specifically for proximal humerus fractures have allowed the expansion of surgical indications permitting surgeons to address more complicated fractures. Advanced preoperative imaging and fluoroscopy allow a better understanding of fracture patterns and permit the surgeon to use this knowledge intraoperatively. Research is required to further validate fracture classification systems, to develop surgical guidelines for decision making, and to compare the outcomes of the various treatments options for proximal humerus fractures.

  10. Linear Design Approach to a Fuzzy Controller

    DEFF Research Database (Denmark)

    Jantzen, Jan

    1999-01-01

    A ball-balancer, basically an inverted pendulum problem, is stabilised by a linear controller. With certain design choices, a fuzzy controller is equivalent to a summation; thus it can replace the linear controller. It can be claimed, that the fuzzy controller performs at least as well...... as the linear controller, since the linear controller is contained in the fuzzy controller. The approach makes it somewhat easier to design a fuzzy controller....

  11. Scaphoid Waist Internal Fixation for Fractures Trial (SWIFFT) protocol: a pragmatic multi-centre randomised controlled trial of cast treatment versus surgical fixation for the treatment of bi-cortical, minimally displaced fractures of the scaphoid waist in adults.

    Science.gov (United States)

    Dias, Joseph; Brealey, Stephen; Choudhary, Surabhi; Cook, Liz; Costa, Matthew; Fairhurst, Caroline; Hewitt, Catherine; Hodgson, Stephen; Jefferson, Laura; Jeyapalan, Kanagaratnam; Keding, Ada; Leighton, Paul; Rangan, Amar; Richardson, Gerry; Rothery, Claire; Taub, Nicholas; Thompson, John; Torgerson, David

    2016-06-04

    this. The SWIFFT Trial is a rigorously designed and adequately powered study which aims to contribute to the evidence-base to inform clinical decisions for the treatment of this common fracture in adults. The trial is registered with the International Standard Randomised Controlled Trial Register ( ISRCTN67901257 ). Date registration assigned was 13/02/2013.

  12. Medial Malleoli Fractures: Clinical Comparison Between Newly Designed Sled Device and Conventional Screws.

    Science.gov (United States)

    Maniar, Hemil; Kempegowda, Harish; Tawari, Akhil A; Rutter, Michael R; Borade, Amrut; Cush, Gerard; Horwitz, Daniel S

    2017-08-01

    The Trimed Medial Malleolar Sled is a newer device designed to treat medial malleolus fracture. The purpose of this study was to compare the outcome of medial malleolar fractures treated with the sled and conventional malleolar screws. After obtaining an institutional review board approval, we conducted a retrospective study to identify all skeletally mature patients who sustained an ankle fracture with medial malleolar involvement treated with the sled and we identified a matched cohort treated with conventional malleolar screws. The patients were divided into 2 groups: group A included patients treated with malleolar screws and group B included patients treated with the sled device. The outcomes measured included rate of union, implant removal, and pain over the implant site. Eighty-five medial malleolar ankle fractures were divided into 2 groups: group A included patients (n = 64) treated with malleolar screws and group B included patients (n = 21) treated with the sled device. In group A (n = 64), 62 patients (96.8%) achieved radiological union with a mean union rate of 11 weeks and 10 (15%) patients underwent repeat surgery for implant removal of which 3 patients (4.6%) had pain specifically over the medial implant. In group B (n = 21), all of the patients (100%) achieved radiological union with a mean union rate of 10.8 weeks and 3 patients (14.2%) underwent repeat surgery of which 1 (4.7%) was related to the medial pain. There is no significant difference between the groups for the outcomes measured, including rate of union (  P = .93), visual analog scale score for pain (  P = .07), implant removal (  P = .41), and pain over the implant site (  P = .88). Based on the data from our study, we conclude that there are no major differences between the sled devices and conventional screws relating to union rate and complications. Level III: Observational study.

  13. Control effect of fracture on hard coal cracking in a fully mechanized longwall top coal caving face

    Institute of Scientific and Technical Information of China (English)

    WEI Jin-ping; LI Zhong-hua; SANG Pei-miao; CHEN Shang-qiang

    2009-01-01

    Through theoretical analysis,simulation test and practice,the law of a fracture's influence on hard top coal press cracking was studied.The study focused on the relation between fracture and coal strength,top coal caving ability and work face layout.Based on the investigation of the fracture system,the control of press cracking was achieved by matching working face to fracture orientation to improve top-coal caving ability and recov-ery.The matching principle was pointed out: The top-coal caving working face should be perpendicular to or obliquely cross the primary fracture at a large angle,and cross the secondary fracture at a small angle.The rational match can increase the recovery ratio of top-coal and avoid rib spalling.The application of control technology on hard top coal press cracking was introduced at the Iongwall top-coal caving face.

  14. Lumbar lordosis and pars interarticularis fractures: a case-control study

    Energy Technology Data Exchange (ETDEWEB)

    Bugg, William G.; Lewis, Mark; Juette, Arne; Cahir, John G.; Toms, Andoni P. [Cotman Centre, Norwich Radiology Academy, Norwich, Norfolk (United Kingdom)

    2012-07-15

    The aim of this study is to examine the relationship between lumbar lordosis and pars interarticularis fractures. In this retrospective case-control study we compare the angle of lumbar lordosis and the angle of the S1 vertebral endplate (as a measure of pelvic tilt) in patients with bilateral L5 pars interarticularis fractures with age- and sex-matched control cases with normal MRI examinations of the lumbar spine. Twenty-nine cases of bilateral L5 pars interarticularis fractures with matched control-cases were identified on MRI (16 male, 13 female, age 9-63 years). The angle of lordosis was measured between the inferior L4 and superior S1 vertebral endplates on a standing lateral lumbar spine radiograph for both groups. The mean angle of lordosis about the L5 vertebra was 36.9 (SD = 6.5 ) in the pars interarticularis fracture group, and 30.1 (SD = 6.4 ) in the control group. The difference between the two groups was significant (mean difference 6.8 , Student's t test: P < 0.001). The mean angle of sacral tilt measured was 122.2 (SD = 10.16 ) for controls and 136.4 (SD = 10.86 ) for patients with pars defects. The difference in the means of 14.2 was statistically significantly different (P < 0.0001). Sacral tilt represented by a steeply angled superior endplate of S1 is associated with a significantly increased angle of lordosis, between L4 and S1, and pars fractures at L5. Steep angulation of the first sacral vertebral segment maybe the predisposing biomechanical factor that leads to pincer-like impingement of the pars interarticularis and then spondylolysis. (orig.)

  15. Odanacatib for the treatment of postmenopausal osteoporosis: development history and design and participant characteristics of LOFT, the Long-Term Odanacatib Fracture Trial.

    Science.gov (United States)

    Bone, H G; Dempster, D W; Eisman, J A; Greenspan, S L; McClung, M R; Nakamura, T; Papapoulos, S; Shih, W J; Rybak-Feiglin, A; Santora, A C; Verbruggen, N; Leung, A T; Lombardi, A

    2015-02-01

    Odanacatib is a cathepsin K inhibitor investigated for the treatment of postmenopausal osteoporosis. Phase 2 data indicate that 50 mg once weekly inhibits bone resorption and increases bone mineral density, with only a transient decrease in bone formation. We describe the background, design and participant characteristics for the phase 3 registration trial. Odanacatib (ODN) is a selective cathepsin K inhibitor being evaluated for the treatment of osteoporosis. In a phase 2 trial, ODN 50 mg once weekly reduced bone resorption while preserving bone formation and progressively increased BMD over 5 years. We describe the phase III Long-Term ODN Fracture Trial (LOFT), an event-driven, randomized, blinded placebo-controlled trial, with preplanned interim analyses to permit early termination if significant fracture risk reduction was demonstrated. An extension was planned, with participants remaining on their randomized treatment for up to 5 years, then transitioning to open-label ODN. The three primary outcomes were radiologically determined vertebral, hip, and clinical non-vertebral fractures. Secondary end points included clinical vertebral fractures, BMD, bone turnover markers, and safety and tolerability, including bone histology. Participants were women, 65 years or older, with a BMD T-score≤-2.5 at the total hip (TH) or femoral neck (FN) or with a prior radiographic vertebral fracture and a T-score≤-1.5 at the TH or FN. They were randomized to ODN or placebo tablets. All received weekly vitamin D3 (5600 international units (IU)) and daily calcium supplements as needed to ensure a daily intake of approximately 1200 mg. Altogether, 16,713 participants were randomized at 387 centers. After a planned interim analysis, an independent data monitoring committee recommended that the study be stopped early due to robust efficacy and a favorable benefit/risk profile. Following the base study closeout, 8256 participants entered the study extension. This report details the

  16. INVESTIGATION OF FRACTURE DESIGN FOR MEDIUM CARBON STEEL UNDER EXTRA-LOW CYCLIC FATIGUE IN AXIAL LOADING

    Institute of Scientific and Technical Information of China (English)

    Youtang Li; Shuai Tan; Hongyan Duan

    2008-01-01

    The extra-low cyclic fracture problem of medium carbon steel under axial fatigue loading was investigated.Several problems,such as the relations of the cycle times to the depth and tip radius of the notch,loading frequency,loading range and the parameters of fracture design for medium carbon steel on condition of extra-low axial fatigue loading were discussed based on the experiments.Experimental results indicated that the tension-pressure fatigue loading mode was suitable for extra-low cyclic fatigue fracture design of medium carbon steel and it resulted in low energy consumption,fracture surface with high quality,low cycle times,and high efficiency.The appropriate parameters were as follows:loading frequency 3-5 Hz,notch tip radius r=(0.2-0.3)mm,opening angle α=60°,and notch depth t=(0.14-0.17)D.

  17. Controller Design Automation for Aeroservoelastic Design Optimization of Wind Turbines

    NARCIS (Netherlands)

    Ashuri, T.; Van Bussel, G.J.W.; Zaayer, M.B.; Van Kuik, G.A.M.

    2010-01-01

    The purpose of this paper is to integrate the controller design of wind turbines with structure and aerodynamic analysis and use the final product in the design optimization process (DOP) of wind turbines. To do that, the controller design is automated and integrated with an aeroelastic simulation

  18. 10 CFR 72.146 - Design control.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Design control. 72.146 Section 72.146 Energy NUCLEAR... Design control. (a) The licensee, applicant for a license, certificate holder, and applicant for a CoC... shall establish measures for the identification and control of design interfaces and for...

  19. Prevention of brittle fracture of steel structures by controlling the local stress and strain fields

    Directory of Open Access Journals (Sweden)

    Moyseychik Evgeniy Alekseevich

    Full Text Available In the article the author offers a classification of the methods to increase the cold resistance of steel structural shapes with a focus on the regulation of local fields of internal stresses and strains to prevent brittle fracture of steel structures. The need of a computer thermography is highlighted not only for visualization of temperature fields on the surface, but also to control the fields of residual stresses and strains in a controlled element.

  20. Damage control in thoracic and lumbar unstable fractures in polytrauma. Systematic review

    Directory of Open Access Journals (Sweden)

    Javier Peña Chávez

    2015-06-01

    Full Text Available The objective of this systematic review was to integrate the information from existing studies to determine the level of evidence and grade of recommendation of the implementation of damage control in unstable thoracic and lumbar fractures in polytraumatized patients. Eighteen papers were collected from different databases by keywords and Mesh terms; the level of evidence and grade of recommendation, the characteristics of the participants, the time of fracture fixation, the type of approach and technique used, the length of stay in the intensive care unit, the days of dependence on mechanical ventilator, and the incidence of complications in patients were assessed. The largest proportion of the studies were classified as level 4 evidence and grade C of recommendation which is favorable to the implementation of damage control in unstable thoracic and lumbar fractures in polytraumatized patients as a positive recommendation, although not conclusive. Most papers advocate fracture stabilization within 72 hours of the injury which is associated with a lower incidence of complications, hospital stay, stay in the intensive care unit and lower mortality.

  1. Mechanical engineers' handbook, design, instrumentation, and controls

    CERN Document Server

    Kutz, Myer

    2015-01-01

    Full coverage of electronics, MEMS, and instrumentation andcontrol in mechanical engineering This second volume of Mechanical Engineers' Handbookcovers electronics, MEMS, and instrumentation and control, givingyou accessible and in-depth access to the topics you'll encounterin the discipline: computer-aided design, product design formanufacturing and assembly, design optimization, total qualitymanagement in mechanical system design, reliability in themechanical design process for sustainability, life-cycle design,design for remanufacturing processes, signal processing, dataacquisition and dis

  2. Effect of preparation design on the fracture resistance of zirconia crown copings.

    Science.gov (United States)

    Beuer, Florian; Aggstaller, Hans; Edelhoff, Daniel; Gernet, Wolfgang

    2008-05-01

    The aim of this in vitro study was to evaluate the effects of different preparation designs on the fracture resistance of single-crown zirconia frameworks. To this end, maxillary molar dies of CrCo alloy were fabricated with five different preparation designs: shoulderless, slight and pronounced deep chamfer, beveled and non-beveled shoulder. Ten zirconia copings with a wall thickness of 0.4 mm were fabricated for each type of preparation. After cementation by glass ionomer cement, they were loaded until fracture. There were significant differences in the breaking load of the experimental groups (ANOVA, p < 0.01). The shoulder preparation had a mean breaking load of 2286 N, the shoulderless preparation 2041 N, the beveled shoulder 1722 N, the pronounced deep chamfer 1752 N, and the slight chamfer 1624 N. Based on the results of this study, a shoulder preparation is highly recommended whenever possible. Moreover, for endodontically treated teeth that are structurally compromised or which have anatomically limited areas, the slight chamfer preparation is an optimal recommendation.

  3. Fracture mechanics based design for radioactive material transport packagings -- Historical review

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.A.; Salzbrenner, D.; Sorenson, K.; McConnell, P.

    1998-04-01

    The use of a fracture mechanics based design for the radioactive material transport (RAM) packagings has been the subject of extensive research for more than a decade. Sandia National Laboratories (SNL) has played an important role in the research and development of the application of this technology. Ductile iron has been internationally accepted as an exemplary material for the demonstration of a fracture mechanics based method of RAM packaging design and therefore is the subject of a large portion of the research discussed in this report. SNL`s extensive research and development program, funded primarily by the U. S. Department of Energy`s Office of Transportation, Energy Management and Analytical Services (EM-76) and in an auxiliary capacity, the office of Civilian Radioactive Waste Management, is summarized in this document along with a summary of the research conducted at other institutions throughout the world. In addition to the research and development work, code and standards development and regulatory positions are also discussed.

  4. Design tool for wind turbine control algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Van der Hooft, E.L.; Van Engelen, T.G.; Schaak, P.; Wiggelinkhuizen, E.J. [ECN Wind Energy, Petten (Netherlands)

    2004-11-01

    Advanced wind turbine control algorithms have become more important over the last years in order to deal with high requirements on reliability, cost of energy and extreme operating (offshore) conditions. An open source modular 'Design tool for wind turbine control algorithms' within the Matlab environment enables possibilities for wind turbine designers to develop industrial control algorithms and to utilize the benefits of more advanced control solutions. The design tool offers a proven design procedure, which takes the different design stages of a wind turbine into account. It supports initial design and evaluation of control algorithms, linking to aero-elastic codes and implementation in the turbine controller. In addition, the tool assists the designer to operate the design procedure, to avoid design failures and ordering of all the design data, models and versions. Currently, the incorporated design and evaluation models are focussed on design of classic 'rotor speed feedback control' for a variable speed and active pitch turbine and have been verified in practice. More advanced control design modules are within reach as a result of current developments on frequency domain analysis and synthesis of (linearised) turbine models.

  5. Post-discharge management following hip fracture - get you back to B4: A parallel group, randomized controlled trial study protocol

    Directory of Open Access Journals (Sweden)

    Brown Roy A

    2011-06-01

    Full Text Available Abstract Background Fall-related hip fractures result in significant personal and societal consequences; importantly, up to half of older adults with hip fracture never regain their previous level of mobility. Strategies of follow-up care for older adults after fracture have improved investigation for osteoporosis; but managing bone health alone is not enough. Prevention of fractures requires management of both bone health and falls risk factors (including the contributing role of cognition, balance and continence to improve outcomes. Methods/Design This is a parallel group, pragmatic randomized controlled trial to test the effectiveness of a post-fracture clinic compared with usual care on mobility for older adults following their hospitalization for hip fracture. Participants randomized to the intervention will attend a fracture follow-up clinic where a geriatrician and physiotherapist will assess and manage their mobility and other health issues. Depending on needs identified at the clinical assessment, participants may receive individualized and group-based outpatient physiotherapy, and a home exercise program. Our primary objective is to assess the effectiveness of a novel post-discharge fracture management strategy on the mobility of older adults after hip fracture. We will enrol 130 older adults (65 years+ who have sustained a hip fracture in the previous three months, and were admitted to hospital from home and are expected to be discharged home. We will exclude older adults who prior to the fracture were: unable to walk 10 meters; diagnosed with dementia and/or significant comorbidities that would preclude their participation in the clinical service. Eligible participants will be randomly assigned to the Intervention or Usual Care groups by remote allocation. Treatment allocation will be concealed; investigators, measurement team and primary data analysts will be blinded to group allocation. Our primary outcome is mobility

  6. Computer Aided Control System Design (CACSD)

    Science.gov (United States)

    Stoner, Frank T.

    1993-01-01

    The design of modern aerospace systems relies on the efficient utilization of computational resources and the availability of computational tools to provide accurate system modeling. This research focuses on the development of a computer aided control system design application which provides a full range of stability analysis and control design capabilities for aerospace vehicles.

  7. Integrated design approach for controlled mechanical structures

    Energy Technology Data Exchange (ETDEWEB)

    Kiriazov, P. [Bulgarian Academy of Sciences, Sofia (Bulgaria). Inst. of Mechanics

    1998-10-01

    This study is addressed to design problems of controlled mechanical structures (CMS) like robot manipulators and engineering systems with active vibration control that may be subject to arbitrary disturbances. Along with the basic design requirement for strength/load capacity, additional design criteria for CMS are needed to meet the continuously increasing demands for faster response, improved precision and reduced energy consumption. As a CMS is a functionally directed assembly of mutually influencing components: control, actuator, mechanical, and sensor subsystems, a conceptual framework for their integrated design is required. Parameters of these subsystems influencing the dynamic performance of CMS define a matrix that transfers the control inputs into the controlled outputs (accelerations). This transfer matrix plays the key role in the integrated structure-control design. We consider the design optimization problem for CMS having decentralized control architecture. An integrated design criterion for such systems is proposed which is based on optimal trade-off relations between bounds of model uncertainties and control force limits. Optimizing this criterion leads to CMS with maximum degree of robustness. The approach proposed makes it possible a decomposition of the overall design problem into design problems for the CMS`s components. The design concepts are applied to the mechanical subsystem of planar linkage systems. Robust decentralized controllers are designed for a two-degree-of-freedom manipulator with elastic joints. (orig.)

  8. Optimal Control Design with Limited Model Information

    CERN Document Server

    Farokhi, F; Johansson, K H

    2011-01-01

    We introduce the family of limited model information control design methods, which construct controllers by accessing the plant's model in a constrained way, according to a given design graph. We investigate the achievable closed-loop performance of discrete-time linear time-invariant plants under a separable quadratic cost performance measure with structured static state-feedback controllers. We find the optimal control design strategy (in terms of the competitive ratio and domination metrics) when the control designer has access to the local model information and the global interconnection structure of the plant-to-be-controlled. At last, we study the trade-off between the amount of model information exploited by a control design method and the best closed-loop performance (in terms of the competitive ratio) of controllers it can produce.

  9. Dynamic plantar pressure distribution, strength capacity and postural control after Lisfranc fracture-dislocation

    DEFF Research Database (Denmark)

    Mehlhorn, Alexander T; Walther, Markus; Yilmaz, Tayfun

    2017-01-01

    of life. 17 consecutive patients suffering from a Lisfranc fracture dislocation were registered, underwent open reduction and internal fixation and were followed-up for 50.5±25.7months (Mean±SDM). Biomechanical analysis of muscle strength capacities, postural control and plantar pressure distribution...... correlated well with clinical outcome. Altered postural control was evident by a significant reduction in unilateral stance time, from which we calculated a strong correlation between stance time and the isokinetic strength measurement. Plantar pressure measurements revealed a significant reduction in peak...... pressure under the midfoot and of Force-Time Integral beneath the second metatarsal. Sufficient rehabilitation is crucial to the clinical outcome following anatomical open reduction of Lisfranc fracture-dislocation. The present study supports a rehabilitation approach focussing on restoring proprioception...

  10. Pressure vessels design methods using the codes, fracture mechanics and multiaxial fatigue

    Directory of Open Access Journals (Sweden)

    Fatima Majid

    2016-10-01

    Full Text Available This paper gives a highlight about pressure vessel (PV methods of design to initiate new engineers and new researchers to understand the basics and to have a summary about the knowhow of PV design. This understanding will contribute to enhance their knowledge in the selection of the appropriate method. There are several types of tanks distinguished by the operating pressure, temperature and the safety system to predict. The selection of one or the other of these tanks depends on environmental regulations, the geographic location and the used materials. The design theory of PVs is very detailed in various codes and standards API, such as ASME, CODAP ... as well as the standards of material selection such as EN 10025 or EN 10028. While designing a PV, we must design the fatigue of its material through the different methods and theories, we can find in the literature, and specific codes. In this work, a focus on the fatigue lifetime calculation through fracture mechanics theory and the different methods found in the ASME VIII DIV 2, the API 579-1 and EN 13445-3, Annex B, will be detailed by giving a comparison between these methods. In many articles in the literature the uniaxial fatigue has been very detailed. Meanwhile, the multiaxial effect has not been considered as it must be. In this paper we will lead a discussion about the biaxial fatigue due to cyclic pressure in thick-walled PV. Besides, an overview of multiaxial fatigue in PVs is detailed

  11. Design of Grain Dryers’ Control System

    Science.gov (United States)

    Li, Shizhuang; Cao, Shukun; Meng, Wenjing

    2017-06-01

    TMS320F28335 which is a TI high-performance TMS320C28x series 32-bit floating point DSP processor is used as the core of the controller, and the hardware is designed, which includes temperature collection, temperature and humidity collection, moisture detection and motor control. The development environment of the system CCS, and then for the characteristics of grain dryer control system, the control system software modular design, the use of fuzzy control method to achieve food grain motor control, and MATLAB simulation analysis, Fuzzy control is used to control the feasibility of the grain moisture.

  12. A controlled trial to increase detection and treatment of osteoporosis in older patients with a wrist fracture.

    Science.gov (United States)

    Majumdar, Sumit R; Rowe, Brian H; Folk, Deb; Johnson, Jeffrey A; Holroyd, Brian H; Morrish, Donald W; Maksymowych, Walter P; Steiner, Ivan P; Harley, Charles H; Wirzba, Brian J; Hanley, David A; Blitz, Sandra; Russell, Anthony S

    2004-09-07

    Despite the high risk for future fractures and the availability of effective treatments, fewer than 10% to 20% of patients who sustain a fragility fracture are tested or treated for osteoporosis. To improve rates of testing and treatment for osteoporosis in patients with wrist fractures who are seen in the emergency department. Nonrandomized, controlled trial with blinded ascertainment of outcomes. Emergency departments in Edmonton, Alberta, Canada. Persons 50 years of age or older who were treated for a wrist fracture and their physicians. Patients admitted to the hospital or treated for osteoporosis were excluded. Overall, 572 consecutive patients with fractures were screened, and 102 patients (55 intervention, 47 control) and 101 physicians were studied. The primary end point was the prescription of osteoporosis treatment 6 months after fracture. Secondary end points included rates of testing for bone mineral density and patients' knowledge, satisfaction, and quality of life. Faxed physician reminders that contained osteoporosis treatment guidelines endorsed by local opinion leaders and patient education. Control patients received usual care and information about falls and home safety. The median patient age was 66 years. Most patients were female (78%) and white (79%); 70% of patients reported a previous fracture, and 22% had a fall with injury in the previous year. The intervention increased the rates of testing for bone mineral density to 62% (vs. 17% for controls; adjusted relative increase, 3.6 [P < 0.001]) and the rates of osteoporosis treatment to 40% (vs. 10% for controls; adjusted relative increase, 3.8 [P = 0.002]) within 6 months of fracture. Intervention patients were more likely to report a diagnosis of osteoporosis, but other patient-reported outcomes did not differ significantly between groups. This was a small, nonrandomized, controlled study with process-based outcomes. In a multifaceted intervention directed at patients and their physicians

  13. Microindentation for in vivo measurement of bone tissue material properties in atypical femoral fracture patients and controls.

    Science.gov (United States)

    Güerri-Fernández, Roberto C; Nogués, Xavier; Quesada Gómez, José M; Torres Del Pliego, Elisa; Puig, Lluís; García-Giralt, Natalia; Yoskovitz, Guy; Mellibovsky, Leonardo; Hansma, Paul K; Díez-Pérez, Adolfo

    2013-01-01

    Atypical femoral fractures (AFF) associated with long-term bisphosphonates (LTB) are a growing concern. Their etiology is unknown, but bone material properties might be deteriorated. In an AFF series, we analyzed the bone material properties by microindentation. Four groups of patients were included: 6 AFF, 38 typical osteoporotic fractures, 6 LTB, and 20 controls without fracture. Neither typical osteoporotic fractures nor controls have received any antiosteoporotic medication. A general laboratory workup, bone densitometry by dual-energy X-ray absorptiometry (DXA), and microindentation testing at the tibia were done in all patients. Total indentation distance (Total ID), indentation distance increase (IDI), and creep indentation distance (Creep ID) were measured (microns). Age-adjusted analysis of covariance (ANCOVA) was used for comparisons. Controls were significantly younger than fracture groups. Bisphosphonate exposure was on average 5.5 years (range 5 to 12 years) for the AFF and 5.4 years (range 5 to 8 years) for the LTB groups. Total ID (microns) showed better material properties (lower Total ID) for controls 36 (± 6; mean ± SD) than for AFF 46 (± 4) and for typical femoral fractures 47 (± 13), respectively. Patients on LTB showed values between controls and fractures, 38 (± 4), although not significantly different from any of the other three groups. IDI values showed a similar pattern 13 (± 2), 16 (± 6), 19 (± 3), and 18 (± 5). After adjusting by age, significant differences were seen between controls and typical (p Creep ID between groups. Our data suggest that patients with AFF have a deep deterioration in bone material properties at a tissue level similar to that for the osteoporotic fracture group. The LTB group shows levels that are in between controls and both type of fractures, although not statistically different. These results suggest that bisphosphonate therapy probably does not put the majority of patients at risk

  14. Effectiveness of joint mobilisation after cast immobilisation for ankle fracture: a protocol for a randomised controlled trial [ACTRN012605000143628

    Directory of Open Access Journals (Sweden)

    Haas Marion

    2006-05-01

    Full Text Available Abstract Background Passive joint mobilisation is a technique frequently used by physiotherapists to reduce pain, improve joint movement and facilitate a return to activities after injury, but its use after ankle fracture is currently based on limited evidence. The primary aim of this trial is to determine if adding joint mobilisation to a standard exercise programme is effective and cost-effective after cast immobilisation for ankle fracture in adults. Methods/Design Ninety participants will be recruited from the physiotherapy departments of three teaching hospitals and randomly allocated to treatment or control groups using a concealed procedure. All participants will perform an exercise programme. Participants in the treatment group will also receive joint mobilisation twice a week for four weeks. Blinded follow-up assessments will be conducted four, 12 and 24 weeks after randomisation. The primary outcome measures will be the Lower Extremity Functional Scale and the Assessment of Quality of Life. Secondary outcomes will include measures of impairments, activity limitation and participation. Data on the use of physiotherapy services and participants' out-of-pocket costs will be collected for the cost-effective and cost-utility analyses. To test the effects of treatment, between-group differences will be examined with analysis of covariance using a regression approach. The primary conclusions will be based on the four-week follow-up data. Discussion This trial incorporates features known to minimise bias. It uses a pragmatic design to reflect clinical practice and maximise generalisability. Results from this trial will contribute to an evidence-based approach for rehabilitation after ankle fracture.

  15. Design controls for the medical device industry

    CERN Document Server

    Teixeira, Marie B

    2013-01-01

    The second edition of a bestseller, Design Controls for the Medical Device Industry provides a comprehensive review of the latest design control requirements, as well as proven tools and techniques to ensure your company's design control program evolves in accordance with current industry practice. The text assists in the development of an effective design control program that not only satisfies the US FDA Quality System Regulation (QSR) and ISO 9001 and 13485 standards, but also meets today's third-party auditor/investigator expectations and saves you valuable time and money.The author's cont

  16. Acupuncture in Patients with a Vertebral Compression Fracture: A Protocol for a Randomized, Controlled, Pilot Clinical Trial

    Directory of Open Access Journals (Sweden)

    Hyun-jong Lee

    2015-03-01

    Full Text Available Objectives: A vertebral compression fracture (VCF is characterized by back pain and fracture of a vertebral body on spinal radiography. VCFs of the thoraco lumbar spine are common in the elderly. In general, appropriate analgesics should be prescribed to reduce pain and, thus, promote early mobilization. The ideal treatment approach for VCFs has not been determined. In Korea, acupuncture and herbal medication have been used to treat VCFs for many years. There is empirical evidence that acupuncture might benefit patients with a VCF. However, no randomized, controlled, clinical trials evaluating the efficacy and the safety of acupuncture for treating a VCF have been published. Therefore, we designed a randomized, controlled, pilot, clinical trial to obtain information for the design of a further full scale trial. Methods: A five week protocol for a randomized, controlled, pilot, clinical trial is presented. Fourteen patients will be recruited and randomly allocated to two groups: a control group receiving interlaminar epidural steroid injections once a week for three weeks, and an experimental group receiving interlaminar epidural steroid injections plus acupuncture treatment (three acupuncture sessions per week for three weeks, nine sessions in total. The primary outcomes will be the pain intensity (visual analogue scale and PainVisionTM system. The secondary outcome measurements will be the answers on the short form McGill pain questionnaire and the oswestry disability index. Assessments will be made at baseline and at one, three, and five weeks. The last assessment (week five will take place two weeks after treatment cessation. This study will provide both an indication of feasibility and a clinical foundation for a future large scale trial. The outcomes will provide additional resources for incorporating acupuncture into existing treatments, such as nonsteroidal anti-inflammatory medications, narcotics and vertebral augmentation. This article

  17. Fracture characteristics of a soft rock roadway: staged and zoned control

    Energy Technology Data Exchange (ETDEWEB)

    Li Xue-hua; Yao Qiang-ling; Zhang Nong [China University of Mining & Technology, Xuzhou (China). State Key Laboratory of Coal Resource and Mine Safety

    2009-05-15

    An accurate understanding of fracture and cracking in surrounding rock is the key to solving the problem of maintaining a soft-rock roadway. Experimental studies have been done within a typical soft-rock roadway in a coal mine. The components and micro-structural features of the surrounding rock were investigated. The properties of the rocks around the roadway and the process of fracture expansion were tested on site. The results show that crack propagation and run-through are non-uniform and occur in several stages. Key technologies for supporting the roadway by stages in different regions were put forward after considering time effects, local breakdown characteristics and fracture development. Staged concrete spraying, intensive support from anchor bolting (cabling) and control of the grouting process in the surrounding rock are the main parts of strengthened support technology. Practice shows that rock cracking in soft rock surrounding a roadway can be effectively controlled by this support technology. Stability of the rock surrounding the roadway can be achieved. 12 refs., 13 figs., 1 tab.

  18. Fracture control of ground water flow and water chemistry in a rock aquitard.

    Science.gov (United States)

    Eaton, Timothy T; Anderson, Mary P; Bradbury, Kenneth R

    2007-01-01

    There are few studies on the hydrogeology of sedimentary rock aquitards although they are important controls in regional ground water flow systems. We formulate and test a three-dimensional (3D) conceptual model of ground water flow and hydrochemistry in a fractured sedimentary rock aquitard to show that flow dynamics within the aquitard are more complex than previously believed. Similar conceptual models, based on regional observations and recently emerging principles of mechanical stratigraphy in heterogeneous sedimentary rocks, have previously been applied only to aquifers, but we show that they are potentially applicable to aquitards. The major elements of this conceptual model, which is based on detailed information from two sites in the Maquoketa Formation in southeastern Wisconsin, include orders of magnitude contrast between hydraulic diffusivity (K/S(s)) of fractured zones and relatively intact aquitard rock matrix, laterally extensive bedding-plane fracture zones extending over distances of over 10 km, very low vertical hydraulic conductivity of thick shale-rich intervals of the aquitard, and a vertical hydraulic head profile controlled by a lateral boundary at the aquitard subcrop, where numerous surface water bodies dominate the shallow aquifer system. Results from a 3D numerical flow model based on this conceptual model are consistent with field observations, which did not fit the typical conceptual model of strictly vertical flow through an aquitard. The 3D flow through an aquitard has implications for predicting ground water flow and for planning and protecting water supplies.

  19. A metamorphic controller for plant control system design

    Directory of Open Access Journals (Sweden)

    Tomasz Klopot

    2016-07-01

    Full Text Available One of the major problems in the design of industrial control systems is the selection and parameterization of the control algorithm. In practice, the most common solution is the PI (proportional-integral controller, which is simple to implement, but is not always the best control strategy. The use of more advanced controllers may result in a better efficiency of the control system. However, the implementation of advanced control algorithms is more time-consuming and requires specialized knowledge from control engineers. To overcome these problems and to support control engineers at the controller design stage, the paper describes a tool, i.e., a metamorphic controller with extended functionality, for selection and implementation of the most suitable control algorithm. In comparison to existing solutions, the main advantage of the metamorphic controller is its possibility of changing the control algorithm. In turn, the candidate algorithms can be tested through simulations and the total time needed to perform all simulations can be less than a few minutes, which is less than or comparable to the design time in the concurrent design approach. Moreover, the use of well-known tuning procedures, makes the system easy to understand and operate even by inexperienced control engineers. The application was implemented in the real industrial programmable logic controller (PLC and tested with linear and nonlinear virtual plants. The obtained simulation results confirm that the change of the control algorithm allows the control objectives to be achieved at lower costs and in less time.

  20. THEORETICAL AND EXPERIMENTAL STUDIES ON FRACTURE PLANE CONTROL BLAST WITH NOTCHED BOREHOLES

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The results of theoretical studies and field tests on fracture plane control blast with notched boreholes have been introduced. In these studies, the single symmetrical notched borehole was simplified to a pressurized hole with two symmetrical cracks under the state of plane strain. In analyzing the growth and termination of the notch, only quasi-static pressure was considered. In the mean time, the rock to be blasted was considered to be isotropic. Based on the principles of fracture mechanics, the stress components near the tip of the notch were calculated, and the criteria for growth and termination of the notch were established. The growth direction of the notch was also predicted on the basis of strain energy density factor. An approach for estimating the amount of explosive for each hole and the spacing of holes was suggested. Furthermore, field tests were conducted to check the results from the theoretical studies.

  1. A unique peri-prosthetic fracture pattern in well fixed femoral stems with polished, tapered, collarless design of total hip replacement.

    Science.gov (United States)

    Grammatopoulos, George; Pandit, Hemant; Kambouroglou, Gregoris; Deakin, Mark; Gundle, Roger; McLardy-Smith, Peter; Taylor, Adrian; Murray, David

    2011-11-01

    Peri-prosthetic fractures (PPF) are a recognised complication following hip arthroplasty. Prosthesis design and type influence PPF pattern. Surgeons rely on classification systems, such as the Vancouver, to aid treatment planning. This study highlights a specific fracture pattern that occurs with cemented well-fixed polished, tapered, collarless (PTC) stems. We reviewed a consecutive series of 21 PPF around well fixed PTC stems. The majority of the fractures were classified pre-operatively as Vancouver B2 (14/21), but there were also B1 (6/21) and A type fractures. The B2 fractures had common radiological and intra-operative findings: a spiral fracture with extensive fragmentation of bone and cement, debonding of cement from the implant, cement fracture, and a well-fixed cement-bone interface. Reconstruction of these fractures was more difficult than suggested by the radiographs. Two of the six patients who were considered to have a Vancouver B1 fracture underwent open reduction and internal fixation (ORIF), and had treatment-related complications. Retrospective review of the radiographs showed subtle features, such as subsidence of the stem into the centraliser, that are characteristic of a B2 fracture pattern. In summary, it is important to recognise this fracture pattern around secure PTC stems in order to prevent misinterpretation of the fracture as a Vancouver B1 rather than a B2, leading to failure of treatment, and to alert the surgeon that complex reconstruction will be required because of the extensive fragmentation.

  2. Adults With Idiopathic Scoliosis Diagnosed at Youth Experience Similar Physical Activity and Fracture Rate as Controls.

    Science.gov (United States)

    Diarbakerli, Elias; Grauers, Anna; Danielsson, Aina; Gerdhem, Paul

    2017-04-01

    Cross-sectional. To describe physical activity level and fracture rates in adults with idiopathic scoliosis, diagnosed before maturity, and to compare with a control group. A previous study found a lower level of sporting activities in adults treated for idiopathic scoliosis compared with controls. Other studies have shown a lower bone mass in adults with idiopathic scoliosis compared with controls. One thousand two hundred seventy-eight adults (aged 18-71 yr) with idiopathic scoliosis and 214 controls (aged 18-70 yr) were included and answered the International Physical Activity Questionnaire - Short Form (IPAQ-SF) and questions about previous fractures. The three scoliosis treatment groups (untreated n = 360, brace n = 460, and surgically treated n = 458) were compared. Furthermore, a comparison based on onset (juvenile n = 169 or adolescent n = 976) was performed. Achieved weekly moderate activity level and metabolic equivalent task (MET) minutes/week were assessed for patients and controls. Statistical comparisons were made with analysis of covariance with adjustments for age, body mass index, and sex. The proportion achieving weekly moderate activity level was 962 out of 1278 for individuals with idiopathic scoliosis (75%) and 157 out of 214 (73%) for controls (P = 0.40). The scoliosis patients reported 2016 MET-minutes/week (median value) and the controls 2456 (P = 0.06). Fracture rates did not differ (P = 0.72). Fewer surgically treated individuals achieved moderate activity level (P = 0.046) compared with the untreated and the previously braced individuals. No difference was seen regarding MET-minutes/week (P = 0.86). No differences were seen between individuals with a juvenile onset compared with individuals with an adolescent onset (all P ≥ 0.05). Adults with idiopathic scoliosis have similar physical activity level and do not sustain more fractures compared with controls. Adults with surgically treated

  3. Electromagnetic stimulation as coadjuvant in the healing of diaphyseal femoral fractures: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Alfredo Martinez Rondanelli

    2014-07-01

    Full Text Available Introduction: There is controversy in medical literature regarding the use of electromagnetic fields to promote bone healing.Methods: After designing and building devices capable of generating an electromagnetic field for this study, their safety was confirmed and the electromagnetic therapy was randomly allocated and compared to placebo in patients with fracture of the femoral diaphysis. Treatment began six weeks after the fracture and it was administered once a day, during 1 h, for eight consecutive weeks. Twenty devices were built, 10 of which were placebo-devices. Between June 2008 and October 2009, 64 patients were randomized in two different hospitals and were followed for 24 weeks. The mean age was 30 years (18-59 and 81% were males.Results: Healing observed at week 12 was 75% vs. 58% (p= 0.1; at week 18, it was 94% vs. 80% (p= 0.15; and at week 24, it was 94% vs. 87% (p= 0.43 for the device group and the placebo group, respectively.Discussion: This study suggests that an electromagnetic field stimulus can promote earlier bone healing compared to placebo in femoral diaphyseal fractures. Faster bone healing translates into sooner weight bearing, which – in turn – permits quicker return to normal daily activities.

  4. Vertebral fractures in patients with inflammatory bowel disease COMPARED with a healthy population: a prospective case-control study

    Directory of Open Access Journals (Sweden)

    Vázquez Ma

    2012-05-01

    Full Text Available Abstract Background A prospective study was performed to compare the prevalence of morphometric vertebral fractures (MVF between patients with inflammatory bowel disease (IBD and healthy subjects and to identify predictive factors of fracture. Methods A total of 107 patients with IBD (53 with Crohn’s disease and 54 with ulcerative colitis and 51 healthy subjects participated in the study. Information about anthropometric parameters, toxins, previous fractures, and parameters related to this disease were evaluated. The index of vertebral deformity, bone mass density (BMD, and biochemical parameters were calculated. Results A total of 72 fractures were detected in 38.32% of patients with IBD, and 10 fractures were detected in 13.73% of healthy subjects; the risk of fracture in patients with IBD was higher than that in control subjects (OR, 4.03; 95% CI, 1.652–9.847; p p = 0.17 and femoral neck, r = −0.138, p = 0.07. Corticosteroid treatment was not associated with prevalent vertebral fractures nor with taking corticosteroids (r = 0.135, p = 0.14 or the duration for which they were taken (r = 0.08, p = 0.38, whereas this relationship was present in the controls (r = −0.365, p = 0.01. In the multivariate analysis, none of the measured parameters were significantly predictive of fracture, only to manifested IBD. Hypovitaminosis D was observed in 55.14% of patients with IBD. Conclusions The prevalence of morphometric vertebral fractures is higher in patients with IBD than in the healthy population, without association with BMD or corticoid treatment. Simply having IBD was proven to be a predictive factor of fracture. We observed a high incidence of hypovitaminosis D in patients with IBD.

  5. Computer support for mechatronic control system design

    NARCIS (Netherlands)

    van Amerongen, J.; Coelingh, H.J.; de Vries, Theodorus J.A.

    2000-01-01

    This paper discusses the demands for proper tools for computer aided control system design of mechatronic systems and identifies a number of tasks in this design process. Real mechatronic design, involving input from specialists from varying disciplines, requires that the system can be represented

  6. Flight Control Design - Best Practices

    Science.gov (United States)

    2007-11-02

    certains aspects théoriques. Vient d’abord un débat sur les critères de qualités de vol, en particulier sur les spécifications militaires...was designed such that a failure could not result in an unsafe recovery. The system is credited with saving the test aircraft during the evaluation of a...Recherche et développement - Estado Maior da Força Aérea AnalysisCommunications et gestion de SDFA - Centro de Documentação Institute of Military

  7. Effect of pontic framework design on the fracture resistance of implant-supported all-ceramic fixed partial dentures

    Directory of Open Access Journals (Sweden)

    Ozgur Inan

    2009-10-01

    Full Text Available OBJECTIVE: The purpose of this study was to compare the fracture resistance of implant-supported all-ceramic fixed partial dentures, which have three different pontic designs. MATERIAL AND METHODS: Two implants were placed in a metal model simulating mandibular left second premolar and mandibular left second molar. Thirty standardized 3-unit all-ceramic fixed partial dentures with biconvex, convex or concave pontic designs were fabricated using IPS e.max system (n=10. Afterwards, specimens were centrally loaded on the pontics until failure with a universal testing machine. Results were analyzed by Kruskal-Wallis and Mann-Whitney U tests at 5% significance level. RESULTS: The fracture resistance values of all-ceramic fixed partial dentures designed with biconvex, convex or concave pontics were 349.71, 438.20 and 300.78 N, respectively. There were no statistically significant differences between the fracture resistances of the groups (p>0.05, except for convex and concave groups (p<0.05 and p=0.009, respectively. CONCLUSIONS: Convex design showed the best mechanical properties as demonstrated by the high values of fracture resistance.

  8. Effect of extended physiotherapy and high-dose vitamin D on rate of falls and hospital re-admission after acute hip fracture: a randomized controlled trial

    Science.gov (United States)

    Guidelines for post-fracture care of elderly hip fracture patients are not established despite the significant socio-economic burden of post hip fracture morbidity and mortality. Using a factorial design, we studied the effects of extended physiotherapy (supervised 1 hour per day during acute care p...

  9. Dynamic optimization and adaptive controller design

    Science.gov (United States)

    Inamdar, S. R.

    2010-10-01

    In this work I present a new type of controller which is an adaptive tracking controller which employs dynamic optimization for optimizing current value of controller action for the temperature control of nonisothermal continuously stirred tank reactor (CSTR). We begin with a two-state model of nonisothermal CSTR which are mass and heat balance equations and then add cooling system dynamics to eliminate input multiplicity. The initial design value is obtained using local stability of steady states where approach temperature for cooling action is specified as a steady state and a design specification. Later we make a correction in the dynamics where material balance is manipulated to use feed concentration as a system parameter as an adaptive control measure in order to avoid actuator saturation for the main control loop. The analysis leading to design of dynamic optimization based parameter adaptive controller is presented. The important component of this mathematical framework is reference trajectory generation to form an adaptive control measure.

  10. Optimization-based controller design for rotorcraft

    Science.gov (United States)

    Tsing, N.-K.; Fan, M. K. H.; Barlow, J.; Tits, A. L.; Tischler, M. B.

    1993-01-01

    An optimization-based methodology for linear control system design is outlined by considering the design of a controller for a UH-60 rotorcraft in hover. A wide range of design specifications is taken into account: internal stability, decoupling between longitudinal and lateral motions, handling qualities, and rejection of windgusts. These specifications are investigated while taking into account physical limitations in the swashplate displacements and rates of displacement. The methodology crucially relies on user-machine interaction for tradeoff exploration.

  11. Control On Fluid Flow Properties In Sandstone: Interactions Between Diagenesis Processes And Fracture Corridors

    Science.gov (United States)

    Bossennec, Claire; Géraud, Yves; Moretti, Isabelle; Mattioni, Luca

    2016-04-01

    During the development of a fault zone, processes occur at different scales: secondary faults and fractures development in the damage zone while "diagenetic" processes, i.e: fluid rock interaction at the grains size scale, contribute to modify the matrix features. Spatial distribution of these processes is clearly controlled by microstructural transformations induced by fractured corridors and their location. Understanding flowing properties in the associated damage zone contributes to the better modeling of the fluid flow in faulted and fractured reservoirs which could be oil, gas or water bearing. The Lower Triassic Buntsandstein sandstones outcrop of Cleebourg is located in the Hochwald Horst affected by a major NNE-SSW striking fault, and the structure globally dips with 30° toward Rhenish Fault (Upper Rhine Graben main western border fault). The study of the outcrop aims to decipher the fluid-flow scheme and interactions between fracture network and diagenetic features distribution in the damage zone of a fault, located close to major faulted areas, through field and laboratories petrophysical measurements (permeability, thermic conductivity), and samples microstructural and diagenetical descriptions. The outcrop is structurally divided into a 14 meters thick fault core, surrounded by 5 meters thick transition zones, and damage zone of minimum thickness of 40 meters (total thickness unknown, due to the limits of the outcrop). Damage zone includes three fractured corridors, perpendicular to bedding and from 2 to 5 meters thick. Results presented here were acquired in 2 different layers with similar lithology but only on damage zone samples. In entire damage zone, porosity results and thin section description allow to distinguish two different facies: • Fa1 Intermediate porous (porosity of 12%) sandstone with major illite cement and clay content up to 20% (detrital and diagenetic); • Fa2 High porous (porosity >15%) sandstone with quartz feeding

  12. Recursive design of nonlinear H∞ excitation controller

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This work is concerned with the problem of L2 gain disturbance attenuation for nonlinear systems and nonlinear robust control for power systems. In terms of the recurrence design approach proposed, the nonnegative solution of dissipative inequality and the storage function of nonlinear H∞ control for a generator excitation system are acquired. From this storage function, the excitation controller is constructed. Moreover, simulation results manifest the effectiveness of this design method.

  13. Resilient Control Systems: Next Generation Design Research

    Energy Technology Data Exchange (ETDEWEB)

    Craig Rieger

    2009-05-01

    Since digital control systems were introduced to the market more than 30 years ago, the operational efficiency and stability gained through their use have fueled our migration and ultimate dependence on them for the monitoring and control of critical infrastructure. While these systems have been designed for functionality and reliability, a hostile cyber environment and uncertainties in complex networks and human interactions have placed additional parameters on the design expectations for control systems.

  14. Design of Wireless Remote Control Solar Cleaner

    Directory of Open Access Journals (Sweden)

    Ma Zhicai

    2015-01-01

    Full Text Available This paper describes the operation principle and the hardware composition of the wireless remote control cleaner by adopting solar panel power supply mode in detail. The experimental circuit is designed and on based on the designed experimental circuit the wireless remote control solar cleaner is made. The experimental results show that it is feasible that the combination of solar panels and wireless remote control cleaner.

  15. Protocol for the ProFHER (PROximal Fracture of the Humerus: Evaluation by Randomisation trial: a pragmatic multi-centre randomised controlled trial of surgical versus non-surgical treatment for proximal fracture of the humerus in adults

    Directory of Open Access Journals (Sweden)

    Maffulli Nicola

    2009-11-01

    Full Text Available Abstract Background Proximal humeral fractures, which occur mainly in older adults, account for approximately 4 to 5% of all fractures. Approximately 40% of these fractures are displaced fractures involving the surgical neck. Management of this group of fractures is often challenging and the outcome is frequently unsatisfactory. In particular it is not clear whether surgery gives better outcomes than non-surgical management. Currently there is much variation in the use of surgery and a lack of good quality evidence to inform this decision. Methods/Design We aim to undertake a pragmatic UK-based multi-centre randomised controlled trial evaluating the effectiveness and cost-effectiveness of surgical versus standard non-surgical treatment for adults with an acute closed displaced fracture of the proximal humerus with involvement of the surgical neck. The choice of surgical intervention is left to the surgeon, who must use techniques that they are fully experienced with. This will avoid 'learning curve' problems. We will promote good standards of non-surgical care, similarly insisting on care-provider competence, and emphasize the need for comparable provision of rehabilitation for both groups of patients. We aim to recruit 250 patients from a minimum of 18 NHS trauma centres throughout the UK. These patients will be followed-up for 2 years. The primary outcome is the Oxford Shoulder Score, which will be collected via questionnaires completed by the trial participants at 6, 12 and 24 months. This is a 12-item condition-specific questionnaire providing a total score based on the person's subjective assessment of pain and activities of daily living impairment. We will also collect data for other outcomes, including general health measures and complications, and for an economic evaluation. Additionally, we plan a systematic collection of reasons for non-inclusion of eligible patients who were not recruited into the trial, and their baseline

  16. Feedback Control Design for Counterflow Thrust Vectoring

    Science.gov (United States)

    2005-09-01

    in Figures 3 thru 6, but enabled the experimentation to much more closely mimic flight conditions. PID controllers were designed using robust -f1...compensation of both delayed and non-delayed processes. 8 PID controllers often display robustness to incorrect process model order assumptions and...valve saturation is also a significant obstacle. PID controllers are the most commonly used controllers in industrial practice.’ PID control was used

  17. [Percutaneous fluoroscopic and arthroscopic controlled screw fixation of posterior facet fractures of the calcaneus].

    Science.gov (United States)

    Nehme, A; Chaminade, B; Chiron, P; Fabie, F; Tricoire, J-L; Puget, J

    2004-05-01

    We describe a new technique for reduction and percutaneous osteosynthesis of displaced posterior facet fractures of the calcaneus which appears to overcome the problems encountered with other percutaneous methods described for this type of surgery. The method relies on the use of traction which allows automatic reduction of the greater tubersosity. The patient is installed on an orthopedic traction table. Pin traction provides anatomic reduction of the posterior articular surface and restitution of Böhler's angle under fluoroscopic and arthroscopic control. We used this technique in thirteen patients with fifteen displaced posterior facet fractures of the calcaneum. Mean patient age was 50.4 Years. Mean follow-up was twenty Months. We did not have any cutaneous or infectious complications in this short series. In the majority of the cases, the overall functional and physical results were excellent or good. The mean Böhler's angle was 27 degrees, corresponding to 83% correction compared with the healthy side. These preliminary results are encouraging. We were able to restitute calcaneum anatomy, shorten hospital stay, and avoid all skin complications. Indications for this percutaneous technique could be widened. It is a valid alternative to open treatment of posterior facet fractures of the calcaneum.

  18. Building virtual 3D bone fragment models to control diaphyseal fracture reduction

    Science.gov (United States)

    Leloup, Thierry; Schuind, Frederic; Lasudry, Nadine; Van Ham, Philippe

    1999-05-01

    Most fractures of the long bones are displaced and need to be surgically reduced. External fixation is often used but the crucial point of this technique is the control of reduction, which is effected with a brilliance amplifier. This system, giving instantly a x-ray image, has many disadvantages. It implies frequent irradiation to the patient and the surgical team, the visual field is limited, the supplied images are distorted and it only gives 2D information. Consequently, the reduction is occasionally imperfect although intraoperatively it appears acceptable. Using the pains inserted in each fragment as markers and an optical tracker, it is possible to build a virtual 3D model for each principal fragment and to follow its movement during the reduction. This system will supply a 3D image of the fracture in real time and without irradiation. The brilliance amplifier could then be replaced by such a virtual reality system to provide the surgeon with an accurate tool facilitating the reduction of the fracture. The purpose of this work is to show how to build the 3D model for each principal bone fragment.

  19. Fracture resistance of computer-aided design/computer-aided manufacturing-generated composite resin-based molar crowns.

    Science.gov (United States)

    Harada, Akio; Nakamura, Keisuke; Kanno, Taro; Inagaki, Ryoichi; Örtengren, Ulf; Niwano, Yoshimi; Sasaki, Keiichi; Egusa, Hiroshi

    2015-04-01

    The aim of this study was to investigate whether different fabrication processes, such as the computer-aided design/computer-aided manufacturing (CAD/CAM) system or the manual build-up technique, affect the fracture resistance of composite resin-based crowns. Lava Ultimate (LU), Estenia C&B (EC&B), and lithium disilicate glass-ceramic IPS e.max press (EMP) were used. Four types of molar crowns were fabricated: CAD/CAM-generated composite resin-based crowns (LU crowns); manually built-up monolayer composite resin-based crowns (EC&B-monolayer crowns); manually built-up layered composite resin-based crowns (EC&B-layered crowns); and EMP crowns. Each type of crown was cemented to dies and the fracture resistance was tested. EC&B-layered crowns showed significantly lower fracture resistance compared with LU and EMP crowns, although there was no significant difference in flexural strength or fracture toughness between LU and EC&B materials. Micro-computed tomography and fractographic analysis showed that decreased strength probably resulted from internal voids in the EC&B-layered crowns introduced by the layering process. There was no significant difference in fracture resistance among LU, EC&B-monolayer, and EMP crowns. Both types of composite resin-based crowns showed fracture loads of >2000 N, which is higher than the molar bite force. Therefore, CAD/CAM-generated crowns, without internal defects, may be applied to molar regions with sufficient fracture resistance. © 2015 Eur J Oral Sci.

  20. Randomized, double-blind, placebo-controlled trial using lidocaine patch 5% in traumatic rib fractures.

    Science.gov (United States)

    Ingalls, Nichole K; Horton, Zachary A; Bettendorf, Matthew; Frye, Ira; Rodriguez, Carlos

    2010-02-01

    The lidocaine patch 5% was developed to treat postherpetic neuralgia. Anecdotal experience at our institution suggests the lidocaine patch 5% decreases narcotic usage in patients with traumatic rib fractures. This trial was developed to define the patch's efficacy. Patients with rib fractures admitted to the trauma service at our Level I trauma center were enrolled and randomized in a 1 to 1 double-blind manner to receive a lidocaine patch 5% or placebo patch. Fifty-eight patients who met the inclusion criteria were enrolled from January 2007 to August 2008. Demographic and clinical information were recorded. The primary outcomes variable was total narcotic use, analyzed using the 1-tailed Mann-Whitney test. The secondary outcomes variables included non-narcotic pain medication, average pain score, pulmonary complications, and length of stay. Significance was defined based on a 1-sided test for the primary outcome and 2-sided tests for other comparisons, at p rib fractures, gender, trauma mechanism, preinjury lung disease, smoking history, percent of current smokers, and need for placement of chest tube between the lidocaine patch 5% and placebo groups. There was no difference between the lidocaine patch 5% and placebo groups, respectively, with regard to total IV narcotic usage: median, 0.23 units versus 0.26 units; total oral narcotics: median, 4 units versus 7 units; pain score: 5.6 +/- 0.4 versus 6.0 +/- 0.3 (mean +/- SEM); length of stay: 7.8 +/- 1.1 versus 6.2 +/- 0.7; or percentage of patients with pulmonary complications: 72.7% versus 72.0%. The lidocaine patch 5% does not significantly improve pain control in polytrauma patients with traumatic rib fractures.

  1. Orthosis for thoracolumbar burst fractures without neurologic deficit: A systematic review of prospective randomized controlled trials

    Directory of Open Access Journals (Sweden)

    Gabriel Alcala-Cerra

    2014-01-01

    Full Text Available Background: Traditionally, conservative treatment of thoracolumbar (TL burst fractures without neurologic deficit has encompassed the application of an extension brace. However, their effectiveness on maintaining the alignment, preventing posttraumatic deformities, and improving back pain, disability and quality of life is doubtful. Objective: The objective was to identify and summarize the evidence from randomized controlled trials (RCTs to determine whether bracing patients who suffer TL fractures adds benefices to the conservative manage without bracing. Materials and Methods: Seven databases were searched for relevant RCTs that compared the clinical and radiological outcomes of orthosis versus no-orthosis for TL burst fractures managed conservatively. Primary outcomes were: (1 Loss of kyphotic angle; (2 failure of conservative management requiring subsequent surgery; and (3 disability and pain outcomes. Secondary outcomes were defined by health-related quality of life and in-hospital stay. Results: Based on predefined inclusion criteria, only two eligible high-quality RCTs with a total of 119 patients were included. No significant difference was identified between the two groups regarding loss of kyphotic angle, pain outcome, or in-hospital stay. The pooled data showed higher scores in physical and mental domains of the Short-Form Health Survey 36 in the group treated without orthosis. Conclusion and Recommendation: The current evidence suggests that orthosis could not be necessary when TL burst fractures without neurologic deficit are treated conservatively. However, due to limitations related with number and size of the included studies, more RCTs with high quality are desirable for making recommendations with more certainty.

  2. Logical design for computers and control

    CERN Document Server

    Dodd, Kenneth N

    1972-01-01

    Logical Design for Computers and Control Logical Design for Computers and Control gives an introduction to the concepts and principles, applications, and advancements in the field of control logic. The text covers topics such as logic elements; high and low logic; kinds of flip-flops; binary counting and arithmetic; and Boolean algebra, Boolean laws, and De Morgan's theorem. Also covered are topics such as electrostatics and atomic theory; the integrated circuit and simple control systems; the conversion of analog to digital systems; and computer applications and control. The book is recommend

  3. Robust LQR Control Design of Gyroscope

    Directory of Open Access Journals (Sweden)

    Ashok S. Chandak

    2013-04-01

    Full Text Available The basic problem in designing control systems isthe ability to achieve good performance inthepresenceofuncertainties such as outputdisturbances, measurement noise or unmodeleddynamics (i.e. robust controllers. Recentdevelopment in the area has been directed towardsdeveloping a consistent design methodology withinthis uncertain environment. The attitude control/momentum management of the space station posesatypical problem in ahighlyuncertain environment(such asmass properties of the Space Station andenvironmental disturbancesas well as parametricuncertainties. The objective of this research is touse LQR control for the position control of spin axisrotor position at reference value in the presence ofparametric uncertainties, external unmeasurabledisturbances and system inherent non-linearitywithdifferenttype’sreference tracking signal areconsidered extensively in this paper.

  4. Fracture Mechanics

    CERN Document Server

    Zehnder, Alan T

    2012-01-01

    Fracture mechanics is a vast and growing field. This book develops the basic elements needed for both fracture research and engineering practice. The emphasis is on continuum mechanics models for energy flows and crack-tip stress- and deformation fields in elastic and elastic-plastic materials. In addition to a brief discussion of computational fracture methods, the text includes practical sections on fracture criteria, fracture toughness testing, and methods for measuring stress intensity factors and energy release rates. Class-tested at Cornell, this book is designed for students, researchers and practitioners interested in understanding and contributing to a diverse and vital field of knowledge. Alan Zehnder joined the faculty at Cornell University in 1988. Since then he has served in a number of leadership roles including Chair of the Department of Theoretical and Applied Mechanics, and Director of the Sibley School of Mechanical and Aerospace Engineering.  He teaches applied mechanics and his research t...

  5. Primary hemiarthroplasty versus conservative treatment for comminuted fractures of the proximal humerus in the elderly (ProCon: A Multicenter Randomized Controlled trial

    Directory of Open Access Journals (Sweden)

    Van der Vis Harm M

    2010-05-01

    Full Text Available Abstract Background Fractures of the proximal humerus are associated with a profound temporary and sometimes permanent, impairment of function and quality of life. The treatment of comminuted fractures of the proximal humerus like selected three-or four-part fractures and split fractures of the humeral head is a demanding and unresolved problem, especially in the elderly. Locking plates appear to offer improved fixation; however, screw cut-out rates ranges due to fracture collapse are high. As this may lead to higher rates of revision surgery, it may be preferable to treat comminuted fractures in the elderly primarily with a prosthesis or non-operatively. Results from case series and a small-sample randomized controlled trial (RCT suggest improved function and less pain after primary hemiarthroplasty (HA; however these studies had some limitations and a RCT is needed. The primary aim of this study is to compare the Constant scores (reflecting functional outcome and pain at one year after primary HA versus non-operative treatment in elderly patients who sustained a comminuted proximal humeral fracture. Secondary aims include effects on functional outcome, pain, complications, quality of life, and cost-effectiveness. Methods/Design A prospective, multi-center RCT will be conducted in nine centers in the Netherlands and Belgium. Eighty patients over 65 years of age, who have sustained a three-or four part, or split head proximal humeral fracture will be randomized between primary hemiarthroplasty and conservative treatment. The primary outcome is the Constant score, which indicates pain and function. Secondary outcomes include the Disability of the Arm and Shoulder (DASH score, Visual Analogue Scale (VAS for pain, radiographic healing, health-related quality of life (Short-form-36, EuroQol-5D and healthcare consumption. Cost-effectiveness ratios will be determined for both trial arms. Outcome will be monitored at regular intervals over the

  6. A MODEL AND CONTROLLER REDUCTION METHOD FOR ROBUST CONTROL DESIGN.

    Energy Technology Data Exchange (ETDEWEB)

    YUE,M.; SCHLUETER,R.

    2003-10-20

    A bifurcation subsystem based model and controller reduction approach is presented. Using this approach a robust {micro}-synthesis SVC control is designed for interarea oscillation and voltage control based on a small reduced order bifurcation subsystem model of the full system. The control synthesis problem is posed by structured uncertainty modeling and control configuration formulation using the bifurcation subsystem knowledge of the nature of the interarea oscillation caused by a specific uncertainty parameter. Bifurcation subsystem method plays a key role in this paper because it provides (1) a bifurcation parameter for uncertainty modeling; (2) a criterion to reduce the order of the resulting MSVC control; and (3) a low order model for a bifurcation subsystem based SVC (BMSVC) design. The use of the model of the bifurcation subsystem to produce a low order controller simplifies the control design and reduces the computation efforts so significantly that the robust {micro}-synthesis control can be applied to large system where the computation makes robust control design impractical. The RGA analysis and time simulation show that the reduced BMSVC control design captures the center manifold dynamics and uncertainty structure of the full system model and is capable of stabilizing the full system and achieving satisfactory control performance.

  7. Improvement on fuzzy controller design techniques

    Science.gov (United States)

    Wang, Paul P.

    1993-01-01

    This paper addresses three main issues, which are somewhat interrelated. The first issue deals with the classification or types of fuzzy controllers. Careful examination of the fuzzy controllers designed by various engineers reveals distinctive classes of fuzzy controllers. Classification is believed to be helpful from different perspectives. The second issue deals with the design according to specifications, experiments related to the tuning of fuzzy controllers, according to the specification, will be discussed. General design procedure, hopefully, can be outlined in order to ease the burden of a design engineer. The third issue deals with the simplicity and limitation of the rule-based IF-THEN logical statements. The methodology of fuzzy-constraint network is proposed here as an alternative to the design practice at present. It is our belief that predicate calculus and the first order logic possess much more expressive power.

  8. Design and Control of the MINDWALKER Exoskeleton

    NARCIS (Netherlands)

    Wang, Shiqian; Wang, Letian; Meijneke, C.; Asseldonk, van E.H.F.; Hoellinger, T.; Cheron, G.; Ivanenko, Y.; Scaleia, La V.; Sylos-Labini, F.; Molinari, M.; Tamburella, F.; Pisotta, I.; Thorsteinsson, F.; Ilzkovitz, M.; Gancet, J.; Nevatia, Y.; Hauffe, R.; Zanow, F.; Kooij, van der H.

    2015-01-01

    Powered exoskeletons can empower paraplegics to stand and walk. Actively controlled hip ab/adduction (HAA) is needed for weight shift and for lateral foot placement to support dynamic balance control and to counteract disturbances in the frontal plane. Here, we describe the design, control, and prel

  9. Advocating "spine damage control" as a safe and effective treatment modality for unstable thoracolumbar fractures in polytrauma patients: a hypothesis

    Directory of Open Access Journals (Sweden)

    Beauchamp Kathryn M

    2009-05-01

    Full Text Available Abstract Background The "ideal" timing and modality of fracture fixation for unstable thoracolumbar spine fractures in multiply injured patients remains controversial. The concept of "damage control orthopedics" (DCO, which has evolved globally in the past decade, provides a safe guidance for temporary external fixation of long bone or pelvic fractures in multisystem trauma. In contrast, "damage control" concepts for unstable spine injuries have not been widely implemented, and the scarce literature in the field remains largely anecdotal. The current practice standards are reflected by two distinct positions, either (1 immediate "early total care" or (2 delayed spine fixation after recovery from associated injuries. Both concepts have inherent risks which may contribute to adverse outcome. Presentation of hypothesis We hypothesize that the concept of "spine damage control" – consisting of immediate posterior fracture reduction and instrumentation, followed by scheduled 360° completion fusion during a physiological "time-window of opportunity" – will be associated with less complications and improved outcomes of polytrauma patients with unstable thoracolumbar fractures, compared to conventional treatment strategies. Testing of hypothesis We propose a prospective multicenter trial on a large cohort of multiply injured patients with an associated unstable thoracolumbar fracture. Patients will be assigned to one of three distinct study arms: (1 Immediate definitive (anterior and/or posterior fracture fixation within 24 hours of admission; (2 Delayed definitive (anterior and/or posterior fracture fixation at > 3 days after admission; (3 "Spine damage control" procedure by posterior reduction and instrumentation within 24 hours of admission, followed by anterior 360° completion fusion at > 3 days after admission, if indicated. The primary and secondary endpoints include length of ventilator-free days, length of ICU and hospital stay, mortality

  10. Promoting mobility after hip fracture (ProMo: study protocol and selected baseline results of a year-long randomized controlled trial among community-dwelling older people

    Directory of Open Access Journals (Sweden)

    Sipilä Sarianna

    2011-12-01

    Full Text Available Abstract Background To cope at their homes, community-dwelling older people surviving a hip fracture need a sufficient amount of functional ability and mobility. There is a lack of evidence on the best practices supporting recovery after hip fracture. The purpose of this article is to describe the design, intervention and demographic baseline results of a study investigating the effects of a rehabilitation program aiming to restore mobility and functional capacity among community-dwelling participants after hip fracture. Methods/Design Population-based sample of over 60-year-old community-dwelling men and women operated for hip fracture (n = 81, mean age 79 years, 78% were women participated in this study and were randomly allocated into control (Standard Care and ProMo intervention groups on average 10 weeks post fracture and 6 weeks after discharged to home. Standard Care included written home exercise program with 5-7 exercises for lower limbs. Of all participants, 12 got a referral to physiotherapy. After discharged to home, only 50% adhered to Standard Care. None of the participants were followed-up for Standard Care or mobility recovery. ProMo-intervention included Standard Care and a year-long program including evaluation/modification of environmental hazards, guidance for safe walking, pain management, progressive home exercise program and physical activity counseling. Measurements included a comprehensive battery of laboratory tests and self-report on mobility limitation, disability, physical functional capacity and health as well as assessments for the key prerequisites for mobility, disability and functional capacity. All assessments were performed blinded at the research laboratory. No significant differences were observed between intervention and control groups in any of the demographic variables. Discussion Ten weeks post hip fracture only half of the participants were compliant to Standard Care. No follow-up for Standard Care or

  11. Educational intervention to reduce falls and fear of falling in patients after fragility fracture: results of a controlled pilot study.

    Science.gov (United States)

    Rucker, Diana; Rowe, Brian H; Johnson, Jeffrey A; Steiner, Ivan P; Russell, Anthony S; Hanley, David A; Maksymowych, Walter P; Holroyd, Brian R; Harley, Charles H; Morrish, Donald W; Wirzba, Brian J; Majumdar, Sumit R

    2006-04-01

    Falls and fear of falling are a major health problem. We sought to determine the effectiveness of an educational intervention in reducing fear of falling and preventing recurrent falls in community-dwelling patients after a fragility fracture. One hundred two community-dwelling patients aged 50 years or older who fell and sustained a wrist fracture and were treated at Emergency Departments in Edmonton, Alberta, Canada (2001-2002) were allocated to either standardized educational leaflets and post-discharge telephone counseling regarding fall prevention strategies ("intervention") or attention-controls ("controls"). Main outcomes were fear of falling and recurrent falls 3 months after fracture. Mean age was 67 years and most patients were female (80%). The majority of falls (76%) leading to fracture occurred outdoors. Three months post-fracture, almost half of patients (48%) reported increased fear of falling and 11 of 102 (11%) reported falling again. The intervention did not reduce the fear of falling (43% had increased fear vs. 53% of controls, adjusted P value=0.55) or decrease recurrent falls (17% fell vs. 5% of controls, adjusted P value=0.059) within 3 months of fracture. An educational intervention undertaken in the Emergency Department was no more effective than usual care in reducing fear of falling or recurrent falls in community-dwelling patients. Future strategies must address a number of dimensions beyond simple education.

  12. Comparison of Marginal Fit and Fracture Strength of a CAD/CAM Zirconia Crown with Two Preparation Designs

    Directory of Open Access Journals (Sweden)

    Hamid Jalali

    2016-08-01

    Full Text Available Objectives: The purpose of this in vitro study was to compare the marginal adaptation and fracture resistance of a zirconia-based all-ceramic restoration with two preparation designs.Materials and Methods: Twenty-four mandibular premolars were randomly divided into two groups (n=12; the conventional group received a peripheral shoulder preparation and the modified group received a buccal shoulder and proximal/lingual chamfer preparation. The marginal fit of the zirconia crowns (Cercon was evaluated using a stereomicroscope. After cementation, load was applied to the crowns. The mean fracture load and the mean marginal gap for each group were analyzed using t-test (P=0.05.Results: The mean marginal gap was 71±16µm in the conventional group and 80±10µm in the modified group, with no significant difference (P=0.161. The mean fracture strength was 830±153N for the conventional group and 775±125N for the modified group, with no significant difference (P=0.396. All but one fracture occurred in the veneering ceramic.Conclusion: Less aggressive preparation of proximal and lingual finish lines for the preservation of tooth structure in all-ceramic restorations does not adversely affect the marginal adaptation or fracture strength of the final restoration.

  13. Hydraulic Fracturing Design of Coal-bed Gas Well%煤层气井水力压裂设计

    Institute of Scientific and Technical Information of China (English)

    张志全; 张军; 许弟龙; 胡东; 张保国; 唐艳

    2001-01-01

    针对煤层气井储层特性和压裂的特殊性,选择了拟三维模型进行水力压裂设计。针对一口具体井的资料进行了模拟计算,计算结果合理。同时就地面注液排量、压裂液稠度系数和地应力差值对裂缝几何形态的影响进行了计算和分析,并提出了相应的建议。%In consideration of reservoir charateristics and particalarity of fracturing of coal-bed gas well,a psuedo 3D fracture model is selected to design the hydraulic fracturing.A simulation calculation is performed with data from a specific well,of which the result is reasonable,at the same time calculation and analysis are conducted on the geometry of fractures based on the displacement of surface injected fluid,density coefficient of fracturing fluid and differential value of earth stress,thus related proposals are made.

  14. [Hip fracture as risk factor for mortality in patients over 65 years of age. Case-control study].

    Science.gov (United States)

    Negrete-Corona, J; Alvarado-Soriano, J C; Reyes-Santiago, L A

    2014-01-01

    Hip fracture among older patients is a devastating injury in most cases. It profoundly affects the physical, mental, functional and social balance that patients used to have and, beyond the orthopedic injury, it reflects the aging process and its dire consequences. Some reports show that up to 50% of patients with hip fracture die within six months and many of those who survive do not recover their baseline independence and function. In recent decades the increase in life expectancy after 60 years of age has led to an exponential growth in hip fractures. This is why it is essential to determine the patient-related and environmental factors leading to the increased mortality rates seen in patients with hip fracture, to improve the survival and quality of life of older adults. The objective was to determine the association between hip fracture and mortality in patients over 65 years of age. An observational, longitudinal, retrospective, descriptive, comparative case-control study was conducted. The clinical records of all patients over 65 years of age admitted to the Orthopedics Service, Hospital Regional , ISSSTE, with a diagnosis of hip fracture during the previous 12 months were analyzed, regardless of the type of fracture and treatment they received. A group of patients without hip fracture was used as control group. Total sample size was 50 patients with hip fracture and 50 patients without hip fracture. The following data were collected in data collection forms: age, sex, time elapsed since the fracture, survival at one year and, in the case of deceased patients, the cause of death (pneumonia, sepsis, arrhythmia, hydroelectrolytic imbalance, heart failure and others). The results obtained are shown as tables and charts to facilitate their visual understanding. Patient demographics show that there were 40 (80%) female patients and 10 (20%) male patients with a diagnosis of hip fracture. The control group included 35 (70%) females and 15 (30) males. An

  15. Fracturing fluid characterization facility (FFCF)

    Energy Technology Data Exchange (ETDEWEB)

    Evans, R.D.; Roegiers, J.C.; Fagan, J.

    1993-12-31

    The Fracturing Fluid Characterization Facility project has as its main focus the design, fabrication, and construction of a high pressure simulator (HPS) and a low pressure simulator (LPS) to be used to experimentally investigate the rheological properties and transport characteristics of proppant laden fracturing fluids. A discussion of each apparatus is provided as well as the auxiliary equipment, and data acquisition and control systems associated with the simulators.

  16. Controller Design of Intelligent Lighting Network

    Institute of Scientific and Technical Information of China (English)

    RONG Xue-juan; NIU Ping-juan; XU Xiu-zhi

    2009-01-01

    Studied are the controller design and basic principles of intelligent lighting network. TI's MSP430F123 is used as a main controller.By using the ZigBee modules (Xbee/Xbee-PRO) and the GSM module(SIM300C) for wireless communications,the lighting control is enabled to access wireless network.This system uses a mobile phone to achieve light on-off directly,which can accomplish wireless control of intelligent lighting in families.

  17. Controlled exfoliation of (100) GaAs-based devices by spalling fracture

    Science.gov (United States)

    Sweet, Cassi A.; Schulte, Kevin L.; Simon, John D.; Steiner, Myles A.; Jain, Nikhil; Young, David L.; Ptak, Aaron J.; Packard, Corinne E.

    2016-01-01

    The importance of exfoliation techniques increases as the semiconductor industry progresses toward thinner devices as a way to reduce material costs and improve performance. The controlled spalling technique is a recently developed substrate removal process that utilizes the physics of fracture to create wafer cleavage parallel to the surface at a precise depth. In this letter, we apply principles of linear elastic fracture mechanics to predict the process conditions needed to exfoliate (100) GaAs of a desired thickness. Spalling can be initiated in a controllable manner, by depositing a stressor film of a residual stress value just below the threshold value to induce a spontaneous spall. Experimental data show process window requirements to controllably spall (100) GaAs. Additionally, experimental spall depth in (100) GaAs compares well to spalling mechanics predictions when the effects of wafer thickness and modulus are considered. To test spalled material quality, III-V single junction photovoltaic devices are lifted off of a (100)-GaAs substrate by spalling methods and electrical characteristics are recorded. No degradation is observed in the spalled device, illustrating the potential of this method to rapidly produce thin, high quality devices.

  18. Mirror therapy for distal radial fractures: A pilot randomized controlled study.

    Science.gov (United States)

    Bayon-Calatayud, Manuel; Benavente-Valdepeñas, Ana Maria; Del Prado Vazquez-Muñoz, Maria

    2016-10-12

    To investigate the efficacy of mirror therapy in reducing pain and disability in patients with distal radial fractures. Pilot randomized controlled study. Twenty-two patients with closed distal radial fracture. Patients were randomly assigned to experimental (= 11) or control (= 11) groups. Researchers were blinded to group allocation. Both groups received conventional physiotherapy. In addition, the experimental group had 15 sessions of mirror therapy (a daily session, 30 min). The control group received the same amount of conventional occupational therapy. Assessment was made from baseline to post-treatment. Pain was measured on a visual analogue scale (VAS). Active wrist extension and Quick-DASH (Disabilities of Arm, Shoulder and Hand) were used to assess functional recovery. Pain, disability, and range of motion improved for both groups after intervention. No significant post-treatment differences were found between groups in Quick-DASH (= 0.409), active wrist extension (= 0.191) and VAS scores (= 0.807). There was no significant difference in active wrist extension between groups. Mirror therapy was not superior to conventional occupational therapy in reducing pain and disability.

  19. Wind energy systems control engineering design

    CERN Document Server

    Garcia-Sanz, Mario

    2012-01-01

    IntroductionBroad Context and MotivationConcurrent Engineering: A Road Map for EnergyQuantitative Robust ControlNovel CAD Toolbox for QFT Controller DesignOutline Part I: Advanced Robust Control Techniques: QFT and Nonlinear SwitchingIntroduction to QFTQuantitative Feedback TheoryWhy Feedback? QFT OverviewInsight into the QFT TechniqueBenefits of QFTMISO Analog QFT Control SystemIntroductionQFT Method (Single-Loop MISO System)Design Procedure OutlineMinimum-Phase System Performance SpecificationsJ LTI Plant ModelsPlant Templates of P?(s), P( j_i )Nominal PlantU-Contour (Stability Bound)Trackin

  20. Design Robust Controller for Rotary Kiln

    Directory of Open Access Journals (Sweden)

    Omar D. Hernández-Arboleda

    2013-11-01

    Full Text Available This paper presents the design of a robust controller for a rotary kiln. The designed controller is a combination of a fractional PID and linear quadratic regulator (LQR, these are not used to control the kiln until now, in addition robustness criteria are evaluated (gain margin, phase margin, strength gain, rejecting high frequency noise and sensitivity applied to the entire model (controller-plant, obtaining good results with a frequency range of 0.020 to 90 rad/s, which contributes to the robustness of the system.

  1. A Study on the Fracture Control of Rock Bolts in High Ground Pressure Roadways of Deep Mines

    Directory of Open Access Journals (Sweden)

    Wen Jinglin

    2015-01-01

    Full Text Available According to the frequent fractures of rock bolts in high ground pressure roadways of deep mines, this paper analyzes the mechanism of fractures and concludes that high ground pressure and material de-fects are main reasons for the fracture of rock bolts. The basic idea of fracture control of rock bolts in high ground pressure roadways of deep mines is to increase the yield load and the limit load of rock bolt materials and reduce the actual load of rock bolts. There are four ways of controlling rock bolt fracture: increasing the rock bolt diameter, strengthening bolt materials, weakening support rigidity and the implementation of double supporting. With the roadway support of the 2302 working face of a coal mine as the project background, this paper carries out a study on the effect of two schemes, increasing the rock bolt diameter and the double supporting technique through methods of theoretical analysis, numerical simulation and so on. It determines the most reasonable diam-eter of rock bolts and the best delay distance of secondary support. Practices indicate that rock bolt fracture can be effectively controlled through the double supporting technique, which strengthens the roof and two sides through the first supporting technique and strengthens side angles through the secondary supporting technique.

  2. Fracture toughness of zirconia ceramic crowns made by feather-edge tooth preparation design

    Directory of Open Access Journals (Sweden)

    Mirković Nemanja

    2012-01-01

    Full Text Available Background/Aim. Fracture toughness determines functional crown strenght and prevents damages on ceramics during mastication. There is a lack of relevant literature data about fracture toughness of crowns made by feather-edge preparation. Mechanical testing of ceramic samples is supposed to show if feather-edge tooth preparation is a successful method for making ceramic crowns without any risk of reduction of their mechanical properties. This research was done to establish effects of feather-edge tooth preparation on fracture toughness of single zirconia ceramic crowns. Methods. The research was performed as an experimental study. Sixty (60 ceramic crowns were made on non-carious extracted human premolars. Thirty (30 crowns were made on the basis of feather-edge preparation (experimental group I. The group II included 30 crowns made on 1 mm rounded shoulder. Crowns fabrication was executed on a copy mill production system “Zirkonzahn” (Zirkonzahn GMBH, Gais, Germany. The spherical compression test was used to determine fracture toughness, using 6 mm diameter ceramic ball. Fracture load for damaging ceramic crown was recorded on a universal testing machine - Zwick, type 1464, with the speed of 0.05 mm/min. Results. The results of this research introduced significant differences between fracture toughness of ceramic samples in every examined group. However, fracture toughness of crowns from both group was above 2 000 N, what was double beyond a recommended value. The mean value of fracture toughness in the feather-edge group was 2 090 N, and in shoulder group it was 2 214 N. Conclusion. This research showed a high fracture toughness of zirconia crowns made on feather-edge preparation. The examined crowns showed a fracture resistance at a sufficient distance in relation to the minimum values of functional loads. Further research of functional loads of these crown is necessary, as well as research of marginal adaptation of cemented crowns and

  3. Integrated Design Tools for Embedded Control Systems

    OpenAIRE

    Jovanovic, D.S.; Hilderink, G.H.; Broenink, Johannes F.; Karelse, F.

    2001-01-01

    Currently, computer-based control systems are still being implemented using the same techniques as 10 years ago. The purpose of this project is the development of a design framework, consisting of tools and libraries, which allows the designer to build high reliable heterogeneous real-time embedded systems in a very short time at a fraction of the present day costs. The ultimate focus of current research is on transformation control laws to efficient concurrent algorithms, with concerns about...

  4. Progress in multirate digital control system design

    Science.gov (United States)

    Berg, Martin C.; Mason, Gregory S.

    1991-01-01

    A new methodology for multirate sampled-data control design based on a new generalized control law structure, two new parameter-optimization-based control law synthesis methods, and a new singular-value-based robustness analysis method are described. The control law structure can represent multirate sampled-data control laws of arbitrary structure and dynamic order, with arbitrarily prescribed sampling rates for all sensors and update rates for all processor states and actuators. The two control law synthesis methods employ numerical optimization to determine values for the control law parameters. The robustness analysis method is based on the multivariable Nyquist criterion applied to the loop transfer function for the sampling period equal to the period of repetition of the system's complete sampling/update schedule. The complete methodology is demonstrated by application to the design of a combination yaw damper and modal suppression system for a commercial aircraft.

  5. Integrated Design Tools for Embedded Control Systems

    NARCIS (Netherlands)

    Jovanovic, D.S.; Hilderink, G.H.; Broenink, Johannes F.; Karelse, F.

    2001-01-01

    Currently, computer-based control systems are still being implemented using the same techniques as 10 years ago. The purpose of this project is the development of a design framework, consisting of tools and libraries, which allows the designer to build high reliable heterogeneous real-time embedded

  6. Bone marrow levels of 25 hydroxy vitamin D are not depressed in cases of hip fracture compared with controls.

    Science.gov (United States)

    Power, J; Taggart, J; Parker, M; Berry, J L; Reeve, J

    2014-06-01

    There is little information on tissue as distinct from plasma levels of vitamin D metabolites in cases of hip fracture compared with controls. Femoral neck fractures in the elderly are associated with increased cortical remodelling and endosteal resorption, leading to regional increases in porosity and reduced cortical thickness. Vitamin D metabolites play a central role in the maintenance of normal serum calcium levels and may, through interactions with parathyroid hormone, exert an important influence on bone structure. To investigate whether hip fracture might be associated with tissue vitamin D deficiency, we have measured by radioimmunoassay the levels of 25 hydroxy vitamin D (25 (OH)D) in bone marrow samples extracted from the proximal femurs of 16 female subjects who had suffered fracture (mean age = 82.1 years, standard error (se) 1.9) and nine sex matched post mortem controls (mean age = 83.8 years, se 2.5). Twenty five (OH)D concentrations were significantly greater in the fracture cases (median = 3.7, IQR = 2.5-3.9 ng/g) than in the control group (median = 1.5, IQR = 0.9-2.3 ng/g; P = 0.0007, non-parametric Wilcoxon/Kruskal-Wallis test). It was suggested in the 1970s that bone loss and hip fracture risk in the UK were driven by vitamin D deficiency. Our results suggest that the alterations in femoral neck bone microstructure and remodelling in hip fracture cannot be assigned to the single cause of relative deficiency of vitamin D. Vitamin D deficiency or insufficiency may nevertheless increase remodelling and loss of bone tissue and contribute causally to a minority of hip fractures. Copyright © 2013 John Wiley & Sons, Ltd.

  7. Pulsed Electromagnetic Fields in the treatment of fresh scaphoid fractures. A multicenter, prospective, double blind, placebo controlled, randomized trial.

    Science.gov (United States)

    Hannemann, Pascal; Göttgens, Kevin W A; van Wely, Bob J; Kolkman, Karel A; Werre, Andries J; Poeze, Martijn; Brink, Peter R G

    2011-05-06

    The scaphoid bone is the most commonly fractured of the carpal bones. In the Netherlands 90% of all carpal fractures is a fracture of the scaphoid bone. The scaphoid has an essential role in functionality of the wrist, acting as a pivot. Complications in healing can result in poor functional outcome. The scaphoid fracture is a troublesome fracture and failure of treatment can result in avascular necrosis (up to 40%), non-union (5-21%) and early osteo-arthritis (up to 32%) which may seriously impair wrist function. Impaired consolidation of scaphoid fractures results in longer immobilization and more days lost at work with significant psychosocial and financial consequences.Initially Pulsed Electromagnetic Fields was used in the treatment of tibial pseudoarthrosis and non-union. More recently there is evidence that physical forces can also be used in the treatment of fresh fractures, showing accelerated healing by 30% and 71% reduction in nonunion within 12 weeks after initiation of therapy. Until now no double blind randomized, placebo controlled trial has been conducted to investigate the effect of this treatment on the healing of fresh fractures of the scaphoid. This is a multi center, prospective, double blind, placebo controlled, randomized trial. Study population consists of all patients with unilateral acute scaphoid fracture. Pregnant women, patients having a life supporting implanted electronic device, patients with additional fractures of wrist, carpal or metacarpal bones and pre-existing impairment in wrist function are excluded. The scaphoid fracture is diagnosed by a combination of physical and radiographic examination (CT-scanning).Proven scaphoid fractures are treated with cast immobilization and a small Pulsed Electromagnetic Fields bone growth stimulating device placed on the cast. Half of the devices will be disabled at random in the factory.Study parameters are clinical consolidation, radiological consolidation evaluated by CT-scanning, functional

  8. Non-Steroid Anti-Inflammatory Drugs Are Better than Acetaminophen on Fever Control at Acute Stage of Fracture.

    Directory of Open Access Journals (Sweden)

    Kuang-Ting Yeh

    Full Text Available In addition to adequate surgical fixation and an aggressive rehabilitation program, pain relief is one of the most critical factors in the acute stage of fracture treatment. The most common analgesics are nonsteroid anti-inflammatory drugs and Acetaminophen, both of which relieve pain and reduce body temperature. In clinical experiences, they exhibit effective pain control; however, their influence on body temperature remains controversial. This study is aimed at determining the effects of analgesics at the acute stage of traumatic fracture by performing a clinical retrospective study of patients with fractures and a fracture animal model. The retrospective study revealed that, in the acetaminophen group, the mean value of postmedication body temperature (BT was significantly higher than that of the premedication BT. The change in BT was highly related with the medication rather than other risk factors. Forty eight 12-week-old male Wistar rats were divided into 6 groups: a control group, fracture group, fracture-Acetaminophen group, Acetaminophen group, fracture-Arcoxia group, and Arcoxia group. Fracture rats were prepared by breaking their unilateral tibia and fibula. Their inflammation conditions were evaluated by measuring their serum cytokine level and their physiological status was evaluated by estimating their central temperature, heart rate, and mean blood pressure. The hepatic adverse effects were assessed by measuring the serum levels of aspartate aminotransferase (sGOT and alanine aminotransferase (sGPT. The central temperature in the fracture-Acetaminophen group exceeded that in the groups fed normal saline water or Arcoxia. Accumulated hepatic injury was presented as steadily ascending curves of sGOT and sGPT. Inflammation-related cytokine levels were not higher in the Acetaminophen fracture group and were significantly lower in the fracture-Arcoxia group. Fever appeared to be aggravated by acetaminophen and more related to the

  9. Non-Steroid Anti-Inflammatory Drugs Are Better than Acetaminophen on Fever Control at Acute Stage of Fracture.

    Science.gov (United States)

    Yeh, Kuang-Ting; Wu, Wen-Tien; Subeq, Yi-Maun; Niu, Chi-Chien; Liao, Kuang-Wen; Chen, Ing-Ho; Wang, Jen-Hung; Lee, Ru-Ping

    2015-01-01

    In addition to adequate surgical fixation and an aggressive rehabilitation program, pain relief is one of the most critical factors in the acute stage of fracture treatment. The most common analgesics are nonsteroid anti-inflammatory drugs and Acetaminophen, both of which relieve pain and reduce body temperature. In clinical experiences, they exhibit effective pain control; however, their influence on body temperature remains controversial. This study is aimed at determining the effects of analgesics at the acute stage of traumatic fracture by performing a clinical retrospective study of patients with fractures and a fracture animal model. The retrospective study revealed that, in the acetaminophen group, the mean value of postmedication body temperature (BT) was significantly higher than that of the premedication BT. The change in BT was highly related with the medication rather than other risk factors. Forty eight 12-week-old male Wistar rats were divided into 6 groups: a control group, fracture group, fracture-Acetaminophen group, Acetaminophen group, fracture-Arcoxia group, and Arcoxia group. Fracture rats were prepared by breaking their unilateral tibia and fibula. Their inflammation conditions were evaluated by measuring their serum cytokine level and their physiological status was evaluated by estimating their central temperature, heart rate, and mean blood pressure. The hepatic adverse effects were assessed by measuring the serum levels of aspartate aminotransferase (sGOT) and alanine aminotransferase (sGPT). The central temperature in the fracture-Acetaminophen group exceeded that in the groups fed normal saline water or Arcoxia. Accumulated hepatic injury was presented as steadily ascending curves of sGOT and sGPT. Inflammation-related cytokine levels were not higher in the Acetaminophen fracture group and were significantly lower in the fracture-Arcoxia group. Fever appeared to be aggravated by acetaminophen and more related to the elevation of hepatic

  10. Biological Systems Thinking for Control Engineering Design

    Directory of Open Access Journals (Sweden)

    D. J. Murray-Smith

    2004-01-01

    Full Text Available Artificial neural networks and genetic algorithms are often quoted in discussions about the contribution of biological systems thinking to engineering design. This paper reviews work on the neuromuscular system, a field in which biological systems thinking could make specific contributions to the development and design of automatic control systems for mechatronics and robotics applications. The paper suggests some specific areas in which a better understanding of this biological control system could be expected to contribute to control engineering design methods in the future. Particular emphasis is given to the nonlinear nature of elements within the neuromuscular system and to processes of neural signal processing, sensing and system adaptivity. Aspects of the biological system that are of particular significance for engineering control systems include sensor fusion, sensor redundancy and parallelism, together with advanced forms of signal processing for adaptive and learning control

  11. Processes controlling the migration and biodegradation of Non-aqueous phase liquids (NAPLs) within fractured rocks in the vadose zone FY97 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Geller, J.T.; Holman, Hoi-Ying; Conrad, M. [and others

    1998-02-01

    Subsurface contamination from volatile organic compounds (VOCs) has been found at many Department of Energy (DOE), Department of Defense (DoD) and industrial sites due to the widespread use of organic solvents and hydrocarbon fuels. At ambient pressures and temperatures in the shallow subsurface, these substances are liquids that are immiscible with water; hence they are commonly designated as non-aqueous phase liquids (NAPLs). At some DOE sites, NAPLs are the presumed source of groundwater contamination in fractured rocks, such as basalts (at Hanford and Idaho National Engineering and Environmental Laboratory (INEEL)), shales (Oak Ridge Y-12 Plant), and welded tuffs (Los Alamos National Laboratory (LANL)). The flow, transport and biodegradation processes controlling NAPL behavior in the vadose zone must be understood in order to establish the possible extent of contamination, the risk to groundwater supplies, and appropriate remediation action. This is particularly important in and sites with deep water tables (such as at Hanford, INEEL and LANL). In fractured rock aquifers, NAPL migration is likely to be dominated by the highly permeable pathways provided by rock fractures and joints. Two- and three-phase fluid phases may be present in vadose zone fractures, including NAPL-gas, NAPL-water (in regions of perched water) and NAPL-water-gas.

  12. Remote Control Guidance Law Design Using Variable Structure Control

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A method of sliding mode variable structure control for the missile body being a time varying system is presented. A remote control guidance law is designed. The method has strong robustness to target's maneuver. To reduce the chattering phenomena, quasi-sliding mode variable structure control method is used. Simulation results show that the proposed method has small miss distance for any kind of maneuvering targets and requires small control energy.

  13. Remote Pressure Control - Considering Pneumatic Tubes in Controller Design

    OpenAIRE

    Rager, David; Neumann, Rüdiger; Murrenhoff, Hubertus

    2016-01-01

    In pneumatic pressure control applications the influence of tubes that connect the valve with the control volume ist mainly neglected. This can lead to stability and robustness issues and limit either control performance or tube length. Modeling and considering tube behavior in controller design procedure allows longer tubes while maintaining the required performance and robustness properties without need for manual tuning. The author\\'s previously published Simplified Fluid Transmission Line...

  14. Controlled air incinerator conceptual design study

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    This report presents a conceptual design study for a controlled air incinerator facility for incineration of low level combustible waste at Three Mile Island Unit 2 (TMI-2). The facility design is based on the use of a Helix Process Systems controlled air incinerator. Cost estimates and associated engineering, procurement, and construction schedules are also provided. The cost estimates and schedules are presented for two incinerator facility designs, one with provisions for waste ash solidification, the other with provisions for packaging the waste ash for transport to an undefined location.

  15. Flying qualities criteria and flight control design

    Science.gov (United States)

    Berry, D. T.

    1981-01-01

    Despite the application of sophisticated design methodology, newly introduced aircraft continue to suffer from basic flying qualities deficiencies. Two recent meetings, the DOD/NASA Workshop on Highly Augmented Aircraft Criteria and the NASA Dryden Flight Research Center/Air Force Flight Test Center/AIAA Pilot Induced Oscillation Workshop, addressed this problem. An overview of these meetings is provided from the point of view of the relationship between flying qualities criteria and flight control system design. Among the items discussed are flying qualities criteria development, the role of simulation, and communication between flying qualities specialists and control system designers.

  16. Risk of hip, subtrochanteric, and femoral shaft fractures among mid and long term users of alendronate: nationwide cohort and nested case-control study

    Science.gov (United States)

    Abrahamsen, Bo; Eiken, Pia; Eastell, Richard

    2016-01-01

    Objectives To determine the skeletal safety and efficacy of long term (≥10 years) alendronate use in patients with osteoporosis. Design Open register based cohort study containing two nested case control studies. Setting Nationwide study of population of Denmark. Participants 61 990 men and women aged 50-94 at the start of treatment, who had not previously taken alendronate, 1996-2007. Interventions Treatment with alendronate. Main outcome measures Incident fracture of the subtrochanteric femur or femoral shaft (ST/FS) or the hip. Non-fracture controls from the cohort were matched to fracture cases by sex, year of birth, and year of initiation of alendronate treatment. Conditional logistic regression models were fitted to calculate odds ratios with and without adjustment for comorbidity and comedications. Sensitivity analyses investigated subsequent treatment with other drugs for osteoporosis. Results 1428 participants sustained a ST/FS (incidence rate 3.4/1000 person years, 95% confidence interval 3.2 to 3.6), and 6784 sustained a hip fracture (16.2/1000 person years, 15.8 to 16.6). The risk of ST/FS was lower with high adherence to treatment with alendronate (medication possession ratio (MPR, a proxy for compliance) >80%) compared with poor adherence (MPR 80% was associated with a decreased risk of hip fracture (0.73, 0.68 to 0.78; Pfracture outcomes, even for over 10 years of continuous use. PMID:27353596

  17. Analysis and design of hybrid control systems

    Energy Technology Data Exchange (ETDEWEB)

    Malmborg, J.

    1998-05-01

    Different aspects of hybrid control systems are treated: analysis, simulation, design and implementation. A systematic methodology using extended Lyapunov theory for design of hybrid systems is developed. The methodology is based on conventional control designs in separate regions together with a switching strategy. Dynamics are not well defined if the control design methods lead to fast mode switching. The dynamics depend on the salient features of the implementation of the mode switches. A theorem for the stability of second order switching together with the resulting dynamics is derived. The dynamics on an intersection of two sliding sets are defined for two relays working on different time scales. The current simulation packages have problems modeling and simulating hybrid systems. It is shown how fast mode switches can be found before or during simulation. The necessary analysis work is a very small overhead for a modern simulation tool. To get some experience from practical problems with hybrid control the switching strategy is implemented in two different software environments. In one of them a time-optimal controller is added to an existing PID controller on a commercial control system. Successful experiments with this hybrid controller shows the practical use of the method 78 refs, 51 figs, 2 tabs

  18. Influence of different composite materials and cavity preparation designs on the fracture resistance of mesio-occluso-distal inlay restoration.

    Science.gov (United States)

    Tekçe, Neslihan; Pala, Kansad; Demirci, Mustafa; Tuncer, Safa

    2016-01-01

    The aim of the study to evaluate the fracture resistance of a computer-aided design/computer-aided manufacturing (CAD/CAM) and three indirect composite materials for three different mesio-occluso-distal (MOD) inlay cavity designs. A total of 120 mandibular third molar were divided into three groups: (G1) non-proximal box, (G2) 2-mm proximal box, and (G3) 4-mm proximal box. Each cavity design received four composite materials: Estenia, Epricord (Kuraray, Japan), Tescera (Bisco, USA), and Cerasmart CAD/CAM blocks (GC, USA). The specimens were subjected to a compressive load at a crosshead speed of 1 mm/min. The data was analyzed using the two-way analysis of variance and Bonferroni post hoc test (p<0.05). Estenia exhibited significantly higher fracture strength than Epricord and Cerasmart in G1. In G2 and G3, there was no significant difference among the four materials. Using a non-proximal box design for the cavity can improve the fracture resistance of the inlay restoration.

  19. Humanoid robot Lola: design and walking control.

    Science.gov (United States)

    Buschmann, Thomas; Lohmeier, Sebastian; Ulbrich, Heinz

    2009-01-01

    In this paper we present the humanoid robot LOLA, its mechatronic hardware design, simulation and real-time walking control. The goal of the LOLA-project is to build a machine capable of stable, autonomous, fast and human-like walking. LOLA is characterized by a redundant kinematic configuration with 7-DoF legs, an extremely lightweight design, joint actuators with brushless motors and an electronics architecture using decentralized joint control. Special emphasis was put on an improved mass distribution of the legs to achieve good dynamic performance. Trajectory generation and control aim at faster, more flexible and robust walking. Center of mass trajectories are calculated in real-time from footstep locations using quadratic programming and spline collocation methods. Stabilizing control uses hybrid position/force control in task space with an inner joint position control loop. Inertial stabilization is achieved by modifying the contact force trajectories.

  20. Design, modeling and control of nanopositioning systems

    CERN Document Server

    Fleming, Andrew J

    2014-01-01

    Covering the complete design cycle of nanopositioning systems, this is the first comprehensive text on the topic. The book first introduces concepts associated with nanopositioning stages and outlines their application in such tasks as scanning probe microscopy, nanofabrication, data storage, cell surgery and precision optics. Piezoelectric transducers, employed ubiquitously in nanopositioning applications are then discussed in detail including practical considerations and constraints on transducer response. The reader is then given an overview of the types of nanopositioner before the text turns to the in-depth coverage of mechanical design including flexures, materials, manufacturing techniques, and electronics. This process is illustrated by the example of a high-speed serial-kinematic nanopositioner. Position sensors are then catalogued and described and the text then focuses on control. Several forms of control are treated: shunt control, feedback control, force feedback control and feedforward control (...

  1. Circulation control STOL aircraft design aspects

    Science.gov (United States)

    Loth, John L.

    1987-01-01

    Since Davidson patented Circulation Control Airfoils in 1960, there have been only 2 aircraft designed and flown with circulation control (CC). Designing with CC is complex for the following reasons: the relation between lift increase and blowing momentum is nonlinear; for good cruise performance one must change the wing geometry in flight from a round to a sharp trailing edge. The bleed air from the propulsion engines or an auxiliary compressor, must be used efficiently. In designing with CC, the propulsion and control aspects are just as important as aerodynamics. These design aspects were examined and linearized equations are presented in order to facilitate a preliminary analysis of the performance potential of CC. The thrust and lift requirements for takeoff make the calculated runway length very sensitive to the bleed air ratio. Thrust vectoring improves performance and can offset nose down pitching moments. The choice of blowing jet to free stream velocity ratio determines the efficiency of applying bleed air power.

  2. Robust Structured Control Design via LMI Optimization

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Stoustrup, Jakob

    2011-01-01

    This paper presents a new procedure for discrete-time robust structured control design. Parameter-dependent nonconvex conditions for stabilizable and induced L2-norm performance controllers are solved by an iterative linear matrix inequalities (LMI) optimization. A wide class of controller...... structures including decentralized of any order, fixed-order dynamic output feedback, static output feedback can be designed robust to polytopic uncertainties. Stability is proven by a parameter-dependent Lyapunov function. Numerical examples on robust stability margins shows that the proposed procedure can...

  3. Case-control study on factors associated with crown fractures in the primary dentition

    Directory of Open Access Journals (Sweden)

    Patrícia CORRÊA-FARIA

    2015-01-01

    Full Text Available The purpose of the present study was to identify the factors associated with dental trauma in preschool children. This case-control study was nested in a population-based cross-sectional study involving a random sample of 301 children one to five years of age in the city of Diamantina, Brazil. The case group was made up of children with at least one fractured deciduous tooth, and the control group was made up of children with no deciduous tooth fracture. The two groups were matched for age in a proportion of one control for every case. The dependent variable was “dental trauma,” diagnosed according to the criteria proposed by Andreasen and Andreasen. The independent variables were overjet, measured and considered accentuated when surpassing 3 mm, and lip coverage, classified as adequate or inadequate. Clinical oral examinations were performed by calibrated dentists. The parents provided information on the socioeconomic indicators. Statistical analysis involved the McNemar test and logistic regression. Each group (case and control was composed of 92 children. In the bivariate analysis, traumatic dental injury (TDI was associated with overjet > 3 mm (p = 0.001, inadequate lip coverage (p < 0.001, mother's schooling (p = 0.028 and household income (p < 0.001. In the multivariate analysis, only inadequate lip coverage was associated with TDI (OR: 5.35; 95% CI: 1.37-20.85. In conclusion, the case group children had a 5.3 - fold more likely chance of presenting inadequate lip coverage, compared with the control children.

  4. Matlab as a robust control design tool

    Science.gov (United States)

    Gregory, Irene M.

    1994-01-01

    This presentation introduces Matlab as a tool used in flight control research. The example used to illustrate some of the capabilities of this software is a robust controller designed for a single stage to orbit air breathing vehicles's ascent to orbit. The global requirements of the controller are to stabilize the vehicle and follow a trajectory in the presence of atmospheric disturbances and strong dynamic coupling between airframe and propulsion.

  5. The Hip Fracture Surgery in Elderly Patients (HIPELD study: protocol for a randomized, multicenter controlled trial evaluating the effect of xenon on postoperative delirium in older patients undergoing hip fracture surgery

    Directory of Open Access Journals (Sweden)

    Coburn Mark

    2012-09-01

    Full Text Available Abstract Background Strategies to protect the brain from postoperative delirium (POD after hip fracture are urgently needed. The development of delirium often is associated with the loss of independence, poor functional recovery, and increased morbidity, as well as increases in length of hospital stay, discharges to nursing facilities, and healthcare costs. We hypothesize that xenon may reduce the burden of POD, (i by avoiding the need to provide anesthesia with a drug that targets the γ-amino-butyric acid (GABAA receptor and (ii through beneficial anesthetic and organ-protective effects. Methods and design An international, multicenter, phase 2, prospective, randomized, blinded, parallel group and controlled trial to evaluate the incidence of POD, diagnosed with the Confusion Assessment Method (CAM, in older patients undergoing hip fracture surgery under general anesthesia with xenon or sevoflurane, for a period of 4 days post surgery (primary outcome is planned. Secondary objectives are to compare the incidence of POD between xenon and sevoflurane, to evaluate the incidence of POD from day 5 post surgery until discharge from hospital, to determine the time to first POD diagnosis, to evaluate the duration of POD, to evaluate the evolution of the physiological status of the patients in the postoperative period, to evaluate the recovery parameters, to collect preliminary data to evaluate the economical impact of POD in the postoperative period and to collect safety data. Patients are eligible if they are older aged (≥ 75 years and assigned to a planned hip fracture surgery within 48 h after the hip fracture. Furthermore, patients need to be willing and able to complete the requirements of this study including the signature of the written informed consent. A total of 256 randomized patients in the 10 participating centers will be recruited, that is, 128 randomized patients in each of the 2 study groups (receiving either xenon or sevoflurane

  6. Controller Architecture Design for MMC-HVDC

    Directory of Open Access Journals (Sweden)

    ZHANG, B.

    2014-05-01

    Full Text Available Compared with high voltage direct current (HVDC, the primary and secondary systems of modular multilevel converter based HVDC (MMC-HVDC are complicated. And the characteristics of the control system determine the properties of the MMC-HVDC system to a certain extent. This paper investigates the design of control architecture. First, the structure and parameters of the 21-level MMC-HVDC are designed. Second, the framework of the control system is studied in details and a complete control system is established. The communication mode and content are built between each layer, and the control system program is developed and debugged. Then The steady state test platform of the sub-module and the relevant control system are designed. Finally, the steady-state tests and the system test of the physical MMC-HVDC simulation system are conducted, which prove that the SMC can control the sub-module (SM efficiently, and the control system could realize efficient start and stop of the physical system. Meanwhile, the capacitor voltage balance between the sub-modules and the basic fault protection and control of the DC voltage and power are verified to be effective.

  7. Kinetics and fracture resistance of lithiated silicon nanostructure pairs controlled by their mechanical interaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seok Woo; /Stanford U., Geballe Lab.; Lee, Hyun-Wook; /Stanford U., Materials Sci. Dept.; Ryu, Ill; /Brown U.; Nix, William D.; /Stanford U., Materials Sci. Dept.; Gao, Huajian; /Brown U.; Cui, Yi; /Stanford U., Materials Sci. Dept. /SLAC

    2015-06-01

    Following an explosion of studies of silicon as a negative electrode for Li-ion batteries, the anomalous volumetric changes and fracture of lithiated single Si particles have attracted significant attention in various fields, including mechanics. However, in real batteries, lithiation occurs simultaneously in clusters of Si in a confined medium. Hence, understanding how the individual Si structures interact during lithiation in a closed space is necessary. Herein, we demonstrate physical/mechanical interactions of swelling Si structures during lithiation using well-defined Si nanopillar pairs. Ex situ SEM and in situ TEM studies reveal that compressive stresses change the reaction kinetics so that preferential lithiation occurs at free surfaces when the pillars are mechanically clamped. Such mechanical interactions enhance the fracture resistance of This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract No. DE-AC02-76SF00515. SLAC-PUB-16300 2 lithiated Si by lessening the tensile stress concentrations in Si structures. This study will contribute to improved design of Si structures at the electrode level for high performance Li-ion batteries.

  8. Stress corrosion-controlled rates of mode I fracture propagation in calcareous bedrock

    Science.gov (United States)

    Voigtlaender, Anne; Leith, Kerry; Krautblatter, Michael

    2014-05-01

    Surface bedrock on natural rock slopes is subject to constant and cyclic environmental stresses (wind, water, wave, ice, seismic or gravitational). Studies indicate that these stresses range up to several hundred kPa, generally too low to cause macroscopic changes in intact rock, although clear evidence of fracture generation, crack propagation and weathering of bedrock illustrates the effect of environmental stresses at the Earth's surface. We suggest that material degradation and its extent, is likely to be controlled by the rate of stress corrosion cracking (SCC). Stress corrosion is a fluid-material reaction, where fluids preferentially react with strained atomic bonds at the tip of developing fractures. Stress corrosion in ferrous and siliceous materials is often accepted as the fracture propagation and degradation rate-controlling process where materials are subject to stresses and fluids. Although evidence for chemical weathering in propagating bedrock fractures is clear in natural environments, the physical system and quantification of stress corrosion in natural rocks is yet to be addressed. Here, we present preliminary data on the relationship between stresses at levels commonly present on natural rock slopes, and material damage resulting from stress corrosion under constant or cyclic tensile loading. We undertake single notch three-point bending tests (SNBT) on fresh calcareous bedrock specimens (1100x100x100mm) over a two-month period. Two beams containing an artificial notch are stressed to 75% of their ultimate strength, and a constant supply of weak acid is applied at the notch tip to enhance chemical reactions. A third, unloaded, beam is also exposed to weak acid in order to elucidate the contribution of stress corrosion cracking to the material degradation. Stresses at the tip of propagating cracks affect the kinetics of the chemical reaction in the specimen exposed to both loading and corrosion, leading to an increase in degradation, and greater

  9. Bisphosphonates for the prevention of fractures in osteogenesis imperfecta: meta-analysis of placebo-controlled trials.

    Science.gov (United States)

    Hald, Jannie D; Evangelou, Evangelos; Langdahl, Bente L; Ralston, Stuart H

    2015-05-01

    Bisphosphonates are widely used off-label in the treatment of patients with osteogenesis imperfecta (OI) with the intention of reducing the risk of fracture. Although there is strong evidence that bisphosphonates increase bone mineral density in osteogenesis imperfecta, the effects on fracture occurrence have been inconsistent. The aim of this study was to gain a better insight into the effects of bisphosphonate therapy on fracture risk in patients with osteogenesis imperfecta by conducting a meta-analysis of randomized controlled trials in which fractures were a reported endpoint. We searched Medline, Embase, and the Cochrane Central Register of Controlled Trials in which the effects of bisphosphonates on fracture risk in osteogenesis imperfecta were compared with placebo and conducted a meta-analysis of these studies using standard methods. Heterogeneity was assessed using the I2 statistic. Six eligible studies were identified involving 424 subjects with 751 patient-years of follow-up. The proportion of patients who experienced a fracture was not significantly reduced by bisphosphonate therapy (Relative Risk [RR] = 0.83 [95% confidence interval 0.69-1.01], p = 0.06) with no heterogeneity between studies (I2  = 0). The fracture rate was reduced by bisphosphonate treatment when all studies were considered (RR = 0.71 [0.52-0.96], p = 0.02), but with considerable heterogeneity (I2  = 36%) explained by one study where a small number of patients in the placebo group experienced a large number of fractures. When this study was excluded, the effects of bisphosphonates on fracture rate was not significant (RR = 0.79 [0.61-1.02], p = 0.07, I2  = 0%). We conclude that the effects of bisphosphonates on fracture prevention in osteogenesis imperfecta are inconclusive. Adequately powered trials with a fracture endpoint are needed to further investigate the risks and benefits of bisphosphonates in this condition.

  10. The Effect of Preparation Design on the Fracture Resistance of Zir-Conia Crown Copings (Computer Associated Design/Computer Associated Machine, CAD/CAM System

    Directory of Open Access Journals (Sweden)

    B. Atashkar

    2011-09-01

    Full Text Available Objective: One of the major problems of all ceramic restorations is their probable fracture against the occlusal force. The aim of the present in-vitro study is was to compare the effect of two marginal designs (chamfer & shoulder on the fracture resistance of zirconia copings, CERCON (CAD/CAM.MATERIALS AND METHODS: This in vitro study was done with single blind experimental technique. One stainless steel dye with 50’ chamfer finish line design (0.8 mm depth was prepared using milling machine. Ten epoxy resin dyes were made, The same dye was retrieved and 50' chamfer was converted into shoulder (1 mm.again ten epoxy resin dyes were made from shoulder dyes. Zirconia cores with 0.4 mm thickness and 35 µm cement Space fabricated on the20 epoxy resin dyes (10 samples chamfer and 10 samples shoulder in a dental laboratory. Then the zirconia cores were cemented on the epoxy resin dyes and underwent a fracture test with a universal testing machine (GOTECH AI-700LAC, Arson, USA and samples were investigated from the point of view of the origin of the failure.RESULT: The mean value of fracture resistance for shoulder margins were 788.90±99.56 N and for the chamfer margins were 991.75±112.00 N. The student’s T-test revealed a statistically significant difference between groups (P=0.001.CONCLUSION: The result of this study indicates that marginal design of the zirconia cores effects on their fracture resistance. A chamfer margin could improve the biomechanical performance of posterior single zirconia crown restorations. This may be because of strong unity and round internal angle in chamfer margin.

  11. Control/structure interaction conceptual design tool

    Science.gov (United States)

    Briggs, Hugh C.

    1990-01-01

    The JPL Control/Structure Interaction Program is developing new analytical methods for designing micro-precision spacecraft with controlled structures. One of these, the Conceptual Design Tool, will illustrate innovative new approaches to the integration of multi-disciplinary analysis and design methods. The tool will be used to demonstrate homogeneity of presentation, uniform data representation across analytical methods, and integrated systems modeling. The tool differs from current 'integrated systems' that support design teams most notably in its support for the new CSI multi-disciplinary engineer. The design tool will utilize a three dimensional solid model of the spacecraft under design as the central data organization metaphor. Various analytical methods, such as finite element structural analysis, control system analysis, and mechanical configuration layout, will store and retrieve data from a hierarchical, object oriented data structure that supports assemblies of components with associated data and algorithms. In addition to managing numerical model data, the tool will assist the designer in organizing, stating, and tracking system requirements.

  12. Robust LQR Control Design of Gyroscope

    Directory of Open Access Journals (Sweden)

    Ashok S. Chandak

    2013-03-01

    Full Text Available The basic problem in designing control systems is the ability to achieve good performance in the presence of uncertainties such as output disturbances, measurement noise or unmodeled dynamics (i.e. robust controllers. Recent development in the area has been directed towards developing a consistent design methodology within this uncertain environment. The attitude control/ momentum management of the space station poses a typical problem in a highly uncertain environment (such as mass properties of the Space Station and environmental disturbances as well as parametric uncertainties. The objective of this research is to use LQR control for the position control of spin axis rotor position at reference value in the presence of parametric uncertainties, external unmeasurable disturbances and system inherent non-linearity with different type’s reference tracking signal are considered extensively in this paper.

  13. Unfalsified Control; Application to automatic flight control system design

    Directory of Open Access Journals (Sweden)

    Adrian-Mihail STOICA

    2011-09-01

    Full Text Available Unfalsified Control Theory has been developed to provide a way for avoiding modeling uncertainties in controller design. It belongs to the class of control methods called Adaptive Supervisory Switching Control, which work by introducing in the control scheme a supervisory unit which chooses, from a set of candidate controllers the one most suited for the current plant. Unfalsified Control works by using a switching logic that dispenses with the need for a-priori knowledge of the dynamic model. At discrete moments of time, using the input/output data recorded up to that point, the supervisory calculates for each candidate controller a performance index, and compares it to a given threshold. Controllers surpassing that threshold are removed from the candidate controller set. This process is called falsification. If the controller in the loop is one such falsified controller it is replaced. In this paper we investigate the suitability of this method for aeronautical control applications. We review the theory behind this control scheme and adapt it to the case of controlling a fighter aircraft. We also provide a case study, where we test this control scheme on a simulated fighter aircraft.

  14. Parametric control systems design with applications in missile control

    Institute of Scientific and Technical Information of China (English)

    DUAN GuangRen; YU HaiHua; TAN Feng

    2009-01-01

    This paper considers parametric control of high-order descriptor linear systems via proportional plus derivative feedback.By employing general parametric solutions to a type of so-called high-order Sylvester matrix equations,complete parametric control approaches for high-order linear systems are presented.The proposed approaches give simple complete parametric expressions for the feedback gains and the closed-loop eigenvector matrices,and produce all the design degrees of freedom.Furthermore,Important special cases are particularly treated.Based on the proposed parametric design approaches,a parametric method for the gain-scheduling controller design of a linear time-varying system is proposed and the design of a BTT missile autopilot is carried out.The simulation results show that the method is superior to the traditional one in sense of either global stability or system performance.

  15. Exercise and fall prevention self-management to reduce mobility-related disability and falls after fall-related lower limb fracture in older people: protocol for the RESTORE (Recovery Exercises and STepping On afteR fracturE) randomised controlled trial.

    Science.gov (United States)

    Sherrington, Catherine; Fairhall, Nicola; Kirkham, Catherine; Clemson, Lindy; Howard, Kirsten; Vogler, Constance; Close, Jacqueline C T; Moseley, Anne M; Cameron, Ian D; Mak, Jenson; Sonnabend, David; Lord, Stephen R

    2016-02-02

    Lasting disability and further falls are common and costly problems in older people following fall-related lower limb and pelvic fractures. Exercise interventions can improve mobility after fracture and reduce falls in older people, however the optimal approach to rehabilitation after fall-related lower limb and pelvic fracture is unclear. This randomised controlled trial aims to evaluate the effects of an exercise and fall prevention self-management intervention on mobility-related disability and falls in older people following fall-related lower limb or pelvic fracture. Cost-effectiveness of the intervention will also be investigated. A randomised controlled trial with concealed allocation, assessor blinding for physical performance tests and intention-to-treat analysis will be conducted. Three hundred and fifty people aged 60 years and over with a fall-related lower limb or pelvic fracture, who are living at home or in a low care residential aged care facility and have completed active rehabilitation, will be recruited. Participants will be randomised to receive a 12-month intervention or usual care. The intervention group will receive ten home visits from a physiotherapist to prescribe an individualised exercise program with motivational interviewing, plus fall prevention education through individualised advice from the physiotherapist or attendance at the group based "Stepping On" program (seven two-hour group sessions). Participants will be followed for a 12-month period. Primary outcome measures will be mobility-related disability and falls. Secondary outcomes will include measures of balance and mobility, falls risk, physical activity, walking aid use, frailty, pain, nutrition, falls efficacy, mood, positive and negative affect, quality of life, assistance required, hospital readmission, and health-system and community-service contact. This study will determine the effect and cost-effectiveness of this exercise self management intervention on mobility

  16. SUBSURFACE REPOSITORY INTEGRATED CONTROL SYSTEM DESIGN

    Energy Technology Data Exchange (ETDEWEB)

    D.C. Randle

    2000-01-07

    The primary purpose of this document is to develop a preliminary high-level functional and physical control system architecture for the potential repository at Yucca Mountain. This document outlines an overall control system concept that encompasses and integrates the many diverse process and communication systems being developed for the subsurface repository design. This document presents integrated design concepts for monitoring and controlling the diverse set of subsurface operations. The Subsurface Repository Integrated Control System design will be composed of a series of diverse process systems and communication networks. The subsurface repository design contains many systems related to instrumentation and control (I&C) for both repository development and waste emplacement operations. These systems include waste emplacement, waste retrieval, ventilation, radiological and air monitoring, rail transportation, construction development, utility systems (electrical, lighting, water, compressed air, etc.), fire protection, backfill emplacement, and performance confirmation. Each of these systems involves some level of I&C and will typically be integrated over a data communications network throughout the subsurface facility. The subsurface I&C systems will also interface with multiple surface-based systems such as site operations, rail transportation, security and safeguards, and electrical/piped utilities. In addition to the I&C systems, the subsurface repository design also contains systems related to voice and video communications. The components for each of these systems will be distributed and linked over voice and video communication networks throughout the subsurface facility. The scope and primary objectives of this design analysis are to: (1) Identify preliminary system-level functions and interfaces (Section 6.2). (2) Examine the overall system complexity and determine how and on what levels the engineered process systems will be monitored, controlled, and

  17. Fracture mechanics

    Science.gov (United States)

    Shannon, John L., Jr.

    1986-01-01

    The application of fracture mechanics to the design of ceramic structures will require the precise measurement of crack growth and fracture resistance of these materials over their entire range of anticipated service temperatures and standardized test methods for making such measurements. The development of a standard test for measuring the plane strain fracture toughness is sought. Stress intensity factor coefficients were determined for three varieties of chevron-notch specimens, and fracture toughness measurements were made on silicon nitrides, silicon carbides, and aluminum oxides to assess the performance of each specimen variety. It was determined that silicon nitride and silicon carbides have flat crack growth resistance curves, but aluminum oxide does not. Additionally, batch-to-batch differences were noticed for the aluminum oxide. Experiments are continuing to explain the rising crack growth resistance and batch-to-batch variations for the aluminum oxide.

  18. Damage-control orthopedics versus early total care in the treatment of borderline high-energy pelvic fractures.

    Science.gov (United States)

    Han, Gengfen; Wang, Ziming; Du, Quanyin; Xiong, Yan; Wang, Yu; Wu, Siyu; Zhang, Bo; Wang, Aimin

    2014-12-01

    The purpose of this study was to compare the effectiveness of damage-control orthopedics (DCO) vs early total care (ETC) in the treatment of borderline high-energy pelvic fractures. Seventy-two patients with borderline high-energy pelvic fractures were retrospectively reviewed; 39 received DCO and 33 received ETC. Demographic data and initial injury severities were comparable between groups, except for Abbreviated Injury Scale (AIS) head scores and Glasgow Coma Scale (GCS) scores. Regarding postoperative complications, the incidence rates of acute lung injury and acute respiratory distress syndrome and the mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score were significantly lower in the DCO group compared with the ETC group. Similar results were also observed in subgroups stratified by age (younger than 40 years and 40 years and older). Regarding patients with Tile B fractures, there was no significant difference between groups in incidence rates of overall postoperative complications. However, in patients with Tile C fractures, especially in those 40 years and older, the DCO group had a lower incidence rate of ALI and had lower APACHE II scores than did the ETC group. This study's findings indicate that DCO is the most suitable therapeutic option for patients with Tile C fractures, especially for those 40 years and older, whereas ETC is preferred for patients with Tile B fractures, provided that it is possible to avoid a second operation as well as any delays in patient mobilization.

  19. Actuator topology design using the controllability Gramian

    DEFF Research Database (Denmark)

    Alves da Silveira, Otávio Augusto; Ono Fonseca, Jun Sérgio; Santos, Ilmar

    2015-01-01

    This work develops a methodology for the optimal design of actuators for the vibration control of flexible structures. The objective is the maximization of a measure of the controllability Gramian. The test case is the embedding of piezoelectric inserts in elastic structures for vibration control...... in modal space. A topology optimization was formulated to distribute two material phases in the domain: a passive linear elastic material and an active linear piezoelectric material, with a volume constraint in the latter. The objective function is the trace of the controllability Gramian of a LQR control...... system. Analytical sensitivities for the finite element model are derived for the objective function and constraints. Results are shown for two dimensional vibration control of a short beam with varying number of electrodes (control inputs) and vibration modes....

  20. Design Intelligent Robust Back stepping Controller

    Directory of Open Access Journals (Sweden)

    Zahra Esmaieli

    2014-01-01

    Full Text Available The increasing demand for multi-degree-of-freedom (DOF continuum robot in presence of highly nonlinear dynamic parameters in a number of industries has motivated a flurry of research in the development of soft computing nonlinear methodology. The robust backstopping controller proposed in this research is used to further demonstrate the appealing features exhibited by the continuum robot. Robust feedback controller is used to position control of continuum robot in presence of uncertainties. Using Lyapunov type stability arguments, a robust backstopping controller is designed to achieve this objective. The controller developed in this research is designed into two steps. Firstly, a robust stabilizing torque is designed for the nominal continuum robot dynamics derived using the constrained Lagrangian formulation based on modified PD backstopping controller. Next, the fuzzy logic methodology applied to it to solution uncertainty problem. The fuzzy model free problem is formulated to estimate the nonlinear formulation of continuum robot. The eventual stability of the controller depends on the torque generating capabilities of the continuum robots.

  1. Control/structure interaction design methodology

    Science.gov (United States)

    Briggs, Hugh C.; Layman, William E.

    1989-01-01

    The Control Structure Interaction Program is a technology development program for spacecraft that exhibit interactions between the control system and structural dynamics. The program objectives include development and verification of new design concepts (such as active structure) and new tools (such as a combined structure and control optimization algorithm) and their verification in ground and possibly flight test. The new CSI design methodology is centered around interdisciplinary engineers using new tools that closely integrate structures and controls. Verification is an important CSI theme and analysts will be closely integrated to the CSI Test Bed laboratory. Components, concepts, tools and algorithms will be developed and tested in the lab and in future Shuttle-based flight experiments. The design methodology is summarized in block diagrams depicting the evolution of a spacecraft design and descriptions of analytical capabilities used in the process. The multiyear JPL CSI implementation plan is described along with the essentials of several new tools. A distributed network of computation servers and workstations was designed that will provide a state-of-the-art development base for the CSI technologies.

  2. Infection control in design and construction work.

    Science.gov (United States)

    Collinge, William H

    2015-01-01

    To clarify how infection control requirements are represented, communicated, and understood in work interactions through the medical facility construction project life cycle. To assist project participants with effective infection control management by highlighting the nature of such requirements and presenting recommendations to aid practice. A 4-year study regarding client requirement representation and use on National Health Service construction projects in the United Kingdom provided empirical evidence of infection control requirement communication and understanding through design and construction work interactions. An analysis of construction project resources (e.g., infection control regulations and room data sheets) was combined with semi-structured interviews with hospital client employees and design and construction professionals to provide valuable insights into the management of infection control issues. Infection control requirements are representationally indistinct but also omnipresent through all phases of the construction project life cycle: Failure to recognize their nature, relevance, and significance can result in delays, stoppages, and redesign work. Construction project resources (e.g., regulatory guidance and room data sheets) can mask or obscure the meaning of infection control issues. A preemptive identification of issues combined with knowledge sharing activities among project stakeholders can enable infection control requirements to be properly understood and addressed. Such initiatives should also reference existing infection control regulatory guidance and advice. © The Author(s) 2015.

  3. Design of control systems with uncertain parameters

    Science.gov (United States)

    Auslander, D. M.; Spear, R. C.; Young, G. E.

    1981-01-01

    A design method for control systems with uncertain parameters is presented. The method utilizes a generalized sensitivity approach which separates the parameter space into regions which produce a system response that satisfies given design criteria and regions which do not. Nonparametric statistics and confidence limits for the binomial distribution are used to determine degree of parameter sensitivity and to locate regions in the parameter space which maximize the probability of producing a desirable system response. In an example it is shown that a given parameter may have to be known to a lesser degree of uncertainty to be able to specify a satisfactory design.

  4. Monitoring and design of stormwater control basins

    Science.gov (United States)

    Veenhuis, J.E.; Parrish, J.H.; Jennings, M.E.

    1989-01-01

    The City of Austin, Texas, has played a pioneering role in the control of urban nonpoint source pollution by enacting watershed and stormwater ordinances, overseeing detailed monitoring programs, and improving design criteria for stormwater control methods. The effectiveness of the methods used in Austin, and perhaps in other areas of the United States, to protect urban water resources has not yet been fully established. Therefore, detailed monitoring programs capable of quantitatively determining the effectiveness of control methods and of stormwater ordinances, are required. The purpose of this report is to present an overview of the City of Austin's stormwater monitoring program, including previous monitoring programs with the U.S. Environmental Protection Agency and the U.S. Geological Survey, and to describe the relation of monitoring to design of stormwater control basins.

  5. Quadrocopter Control Design and Flight Operation

    Science.gov (United States)

    Karwoski, Katherine

    2011-01-01

    A limiting factor in control system design and analysis for spacecraft is the inability to physically test new algorithms quickly and cheaply. Test flights of space vehicles are costly and take much preparation. As such, EV41 recently acquired a small research quadrocopter that has the ability to be a test bed for new control systems. This project focused on learning how to operate, fly, and maintain the quadrocopter, as well as developing and testing protocols for its use. In parallel to this effort, developing a model in Simulink facilitated the design and analysis of simple control systems for the quadrocopter. Software provided by the manufacturer enabled testing of the Simulink control system on the vehicle.

  6. The design of multirate digital control systems

    Science.gov (United States)

    Berg, M. C.

    1986-01-01

    The successive loop closures synthesis method is the only method for multirate (MR) synthesis in common use. A new method for MR synthesis is introduced which requires a gradient-search solution to a constrained optimization problem. Some advantages of this method are that the control laws for all control loops are synthesized simultaneously, taking full advantage of all cross-coupling effects, and that simple, low-order compensator structures are easily accomodated. The algorithm and associated computer program for solving the constrained optimization problem are described. The successive loop closures , optimal control, and constrained optimization synthesis methods are applied to two example design problems. A series of compensator pairs are synthesized for each example problem. The succesive loop closure, optimal control, and constrained optimization synthesis methods are compared, in the context of the two design problems.

  7. Robust Control Design via Linear Programming

    Science.gov (United States)

    Keel, L. H.; Bhattacharyya, S. P.

    1998-01-01

    This paper deals with the problem of synthesizing or designing a feedback controller of fixed dynamic order. The closed loop specifications considered here are given in terms of a target performance vector representing a desired set of closed loop transfer functions connecting various signals. In general these point targets are unattainable with a fixed order controller. By enlarging the target from a fixed point set to an interval set the solvability conditions with a fixed order controller are relaxed and a solution is more easily enabled. Results from the parametric robust control literature can be used to design the interval target family so that the performance deterioration is acceptable, even when plant uncertainty is present. It is shown that it is possible to devise a computationally simple linear programming approach that attempts to meet the desired closed loop specifications.

  8. SUBSURFACE REPOSITORY INTEGRATED CONTROL SYSTEM DESIGN

    Energy Technology Data Exchange (ETDEWEB)

    C.J. Fernado

    1998-09-17

    The purpose of this document is to develop preliminary high-level functional and physical control system architectures for the proposed subsurface repository at Yucca Mountain. This document outlines overall control system concepts that encompass and integrate the many diverse systems being considered for use within the subsurface repository. This document presents integrated design concepts for monitoring and controlling the diverse set of subsurface operations. The subsurface repository design will be composed of a series of diverse systems that will be integrated to accomplish a set of overall functions and objectives. The subsurface repository contains several Instrumentation and Control (I&C) related systems including: waste emplacement systems, ventilation systems, communication systems, radiation monitoring systems, rail transportation systems, ground control monitoring systems, utility monitoring systems (electrical, lighting, water, compressed air, etc.), fire detection and protection systems, retrieval systems, and performance confirmation systems. Each of these systems involve some level of I&C and will typically be integrated over a data communication network. The subsurface I&C systems will also integrate with multiple surface-based site-wide systems such as emergency response, health physics, security and safeguards, communications, utilities and others. The scope and primary objectives of this analysis are to: (1) Identify preliminary system level functions and interface needs (Presented in the functional diagrams in Section 7.2). (2) Examine the overall system complexity and determine how and on what levels these control systems will be controlled and integrated (Presented in Section 7.2). (3) Develop a preliminary subsurface facility-wide design for an overall control system architecture, and depict this design by a series of control system functional block diagrams (Presented in Section 7.2). (4) Develop a series of physical architectures that

  9. Sliding Mode Control Applied to Reconfigurable Flight Control Design

    Science.gov (United States)

    Hess, R. A.; Wells, S. R.; Bacon, Barton (Technical Monitor)

    2002-01-01

    Sliding mode control is applied to the design of a flight control system capable of operating with limited bandwidth actuators and in the presence of significant damage to the airframe and/or control effector actuators. Although inherently robust, sliding mode control algorithms have been hampered by their sensitivity to the effects of parasitic unmodeled dynamics, such as those associated with actuators and structural modes. It is known that asymptotic observers can alleviate this sensitivity while still allowing the system to exhibit significant robustness. This approach is demonstrated. The selection of the sliding manifold as well as the interpretation of the linear design that results after introduction of a boundary layer is accomplished in the frequency domain. The design technique is exercised on a pitch-axis controller for a simple short-period model of the High Angle of Attack F-18 vehicle via computer simulation. Stability and performance is compared to that of a system incorporating a controller designed by classical loop-shaping techniques.

  10. Simplified microprocessor design for VLSI control applications

    Science.gov (United States)

    Cameron, K.

    1991-01-01

    A design technique for microprocessors combining the simplicity of reduced instruction set computers (RISC's) with the richer instruction sets of complex instruction set computers (CISC's) is presented. They utilize the pipelined instruction decode and datapaths common to RISC's. Instruction invariant data processing sequences which transparently support complex addressing modes permit the formulation of simple control circuitry. Compact implementations are possible since neither complicated controllers nor large register sets are required.

  11. Design of comprehensive test system for detecting overlying strata mining-induced fractures on surface with radon gas

    Institute of Scientific and Technical Information of China (English)

    Zhang Wei; Zhang Dongsheng; Fan Gangwei

    2011-01-01

    Based on radon gas properties and its existing projects applications,we firstly attempted to apply geophysical and chemical properties of radon gas in the field of mining engineering,and imported radioactive measurement method to detect the development process of the overlying strata mining-induced fractures and their contained water quality in underground coal mining,which not only innovates a more simple-fast-reliable detection method,but also further expands the applications of radon gas detection technology in mining field.A 3D simulation design of comprehensive testing system for detecting strata mining-induced fractures on surface with radon gas (CTSR) was carried out by using a large-scale 3D solid model design software Pro/Engineer (Pro/E),which overcame three main disadvantages of “static design thought,2D planar design and heavy workload for remodification design” on exiting design for mining engineering test systems.Meanwhile,based on the simulation design results of Pro/E software,the stability of the jack-screw pressure bar for the key component in CTSR was checked with a material mechanics theory,which provided a reliable basis for materials selection during the latter machining process.

  12. Fracture strength of the remaining dental structure after different cavity preparation designs.

    Science.gov (United States)

    Teixeira, Evisabel Siqueira Simões; Rizzante, Fabio Antonio Piola; Ishikiriama, Sérgio Kiyoshi; Mondelli, José; Furuse, Adilson Yoshio; Mondelli, Rafael Francisco Lia; Bombonatti, Juliana Fraga Soares

    2016-01-01

    The aim of this in vitro study was to evaluate the loss of tooth structure after cavity preparation for direct (retentive) and indirect (nonretentive) restorations and its relationship to the fracture strength of the prepared tooth. Sound human third molars (60 maxillary and 60 mandibular) were randomly assigned into 12 groups (n = 10) according to the type of cavity preparation and the respective buccolingual width. Class II mesio-occlusodistal cavity preparations, for both indirect inlay and direct resin restorations, were prepared with standardized dimensions of one-half, one-third, or one-quarter of the occlusal intercuspal distance. Fracture resistance was lower and weight loss was greater for all nonretentive preparations. Greater losses in weight and fracture resistance occurred when the buccolingual width for both types of cavities increased, except for the weight loss of the one-quarter and one-third indirect cavity preparations in the mandibular molars, and the fracture resistance of the one-half and one-third direct cavity preparations in maxillary molars. Higher tooth structure loss and lower fracture strength were recorded after preparation of the inlay cavities.

  13. Controller Design Of Unicycle Mobile Robot

    Directory of Open Access Journals (Sweden)

    Mohd Zamzuri Abd Rashid

    2012-10-01

    Full Text Available ABSTRACT: The ability of unicycle mobile robot to stand and move around using one wheel has attracted a lot of researchers to conduct studies about the system, particularly in the design of the system mechanisms and the control strategies. This paper reports the investigation done on the design of the controller of the unicycle mobile robot system to maintain its stability in both longitudinal and lateral directions. The controller proposed is a Linear Quadratic Controller (LQR type which is based on the linearized model of the system. A thorough simulation studies have been carried out to find out the performance of the LQR controller. The best controller gain, K acquired through the simulation is selected to be implemented and tested in the experimental hardware. Finally, the results obtained from the experimental study are compared to the simulation results to study the controller efficacy. The analysis reveals that the proposed controller design is able to stabilize the unicycle mobile robot.ABSTRAK: Kemampuan robot satu roda untuk berdiri dan bergerak di sekitar telah menarik minat ramai penyelidik untuk mengkaji sistem robot terutamanya didalam bidang rangka mekanikal dan strategi kawalan robot. Kertas kajian ini melaporkan hasil penyelidikan ke atas strategi kawalan robot bagi memastikan sistem robot satu roda dapat distabilkan dari arah sisi dan hadapan. Strategi kawalan yang dicadang, menggunakan teknik kawalan kuadratik sejajar (Linear Quadratic Control yang berdasarkan model robot yang telah dipermudahkan. Kajian simulasi secara terperinci telah dijalankan bagi mengkaji prestasi strategi kawalan yang dicadangkan. Dari kajian simulasi sistem robot, pemilihan faktor konstan, K yang sesuai di dalam strategi kawalan telah dibuat, agar dapat dilaksanakan ke atas sistem robot yang dibangunkan. Keputusan dari kajian simulasi dan tindak balas oleh sistem robot yang dibangunkan akhirnya dibandingkan bagi melihat kesesuaian faktor kostan, K

  14. Bone mineral density, bone turnover markers and fractures in patients with systemic sclerosis: a case control study.

    Directory of Open Access Journals (Sweden)

    Marco Atteritano

    Full Text Available OBJECTIVE: The aim of our study was to elucidate the pathophysiology of systemic sclerosis-related osteoporosis and the prevalence of vertebral fragility fracture in postmenopausal women with systemic sclerosis (SSc. METHODOLOGY: Fifty-four postmenopausal women with scleroderma and 54 postmenopausal controls matched for age, BMI, and smoking habits were studied. BMD was measured by dual energy-x-ray absorptiometry at spine and femur, and by ultrasonography at calcaneus The markers of bone turnover included serum osteocalcin and urinary deoxypyridinoline. All subjects had a spine X-ray to ascertain the presence of vertebral fractures. RESULTS: bone mineral density at lumbar spine (BMD 0.78±0.08 vs 0.88±0.07; p<0,001, femoral neck (BMD: 0.56±0.04 vs 0.72±0.07; p<0,001 and total femur (BMD: 0.57±0.04 vs 0.71±0.06; p<0,001 and ultrasound parameter at calcaneus (SI: 80.10±5.10 vs 94.80±6.10 p<0,001 were significantly lower in scleroderma compared with controls; bone turnover markers and parathyroid hormone level were significantly higher in scleroderma compared with controls, while serum of 25(OHD3 was significantly lower. In scleroderma group the serum levels of 25(OHD3 significantly correlated with PTH levels, BMD, stiffness index and bone turnover markers. One or more moderate or severe vertebral fractures were found in 13 patients with scleroderma, wherease in control group only one patient had a mild vertebral fracture. CONCLUSION: Our data shows, for the first time, that vertebral fractures are frequent in subjects with scleroderma, and suggest that lower levels of 25(OHD3 may play a role in the risk of osteoporosis and vertebral fractures.

  15. Factors Controlling DNAPL Migration in a Fracture Network: Experiments and Simulations

    Science.gov (United States)

    Ji, S.; Yeo, I.; Lee, K.

    2002-12-01

    Groundwater contamination by dense nonaqueous phase liquids (DNAPLs) has received considerable attention in recent years, and the attention on characterizing and quantifying the migration of DNAPL in geological formations has been given to the migration of DNAPL in porous media, not much in fractured rock. The spilled DNAPL that is heavier than water migrates downward to fractured bedrocks under the influence of gravity and is a long-term contaminant source. Although the progress has been accomplished on the development of algorithms for the numerical solution of the macroscopic models of contaminant transport in rock fractures, a lack of fundamental understanding exists concerning the interactive effects of the structural characteristics of fractures and fluid rheology on the patterns of DNAPL migration in a fracture network. In particular, little experimental work has been done on DNAPL migration in a fracture network. The two-dimensional fracture network was built up. Water was applied to both sides of a fracture network to have intended hydraulic head, and TCE was injected into one of vertical fractures. TCE migration process was recorded with digital camcorder. The dynamic macro-modified invasion percolation (DMMIP) model is suggested by integrating groundwater flow factor with MMIP that reflects the capillary effect, gravity-destabilization condition and viscous force of DNAPL. The information gained from experiments was analyzed and used for testing the DMMIP model to characterize the DNAPL migration pathway in a fracture network. DMMIP simulations and laboratory experiments show a good agreement. The results of DMMIP simulations and laboratory experiments show that in addition to gravity force, water viscous force considerably affects migration of DNAPL in rock fractures. This study will provide a step-stone for further developing reliable numerical simulators of the DNAPL migration in a fracture network that are required for the implementation of rational

  16. Design of Threshold Controller Based Chaotic Circuits

    DEFF Research Database (Denmark)

    Mohamed, I. Raja; Murali, K.; Sinha, Sudeshna

    2010-01-01

    We propose a very simple implementation of a second-order nonautonomous chaotic oscillator, using a threshold controller as the only source of nonlinearity. We demonstrate the efficacy and simplicity of our design through numerical and experimental results. Further, we show that this approach of ...

  17. Analysis, Control and Design of Walking Robots

    NARCIS (Netherlands)

    van Oort, Gijs

    2011-01-01

    In this thesis five research questions are discussed that are related to the development of two-legged (bipedal) walking robots. The research questions are categorized in three main topics: analysis, control and actuation and design. The research questions are: - How can we analyze the behavior of a

  18. Design of POLCA material control systems

    NARCIS (Netherlands)

    Riezebos, J.

    2010-01-01

    POLCA is a material control system designed for make-to-order or engineer-to-order companies. These firms have to cope with a high variety of customised products, and strong pressure to provide short throughput times. POLCA constrains the amount of work in progress on the shop floor in order to achi

  19. Main Strategies for Autonomous Robotic Controller Design

    OpenAIRE

    Paterega, I.

    2011-01-01

    This review gives an overall introduction to the artificial evolution mechanism. It presents the main strategies for robotic controller design. It gives a review of the pertinent literature, focusing on approaches that use neural networks, evolutionary computing, and fuzzy logic. Various applications of artificial evolution in robotics are surveyed and classified.

  20. Agile Design of Sewer System Control

    NARCIS (Netherlands)

    Van Nooijen, R.P.; Kolechkina, A.G.; Van Leeuwen, P.E.R.M.; Van Velzen, E.

    2011-01-01

    We describe the first part of an attempt to include stakeholder participation in the design of a central automatic controller for a sewer system in a small pilot project (five subcatchments) and present lessons learned so far. The pilot is part of a project aimed at the improvement of water quality

  1. Design of POLCA material control systems

    NARCIS (Netherlands)

    Riezebos, J.

    2010-01-01

    POLCA is a material control system designed for make-to-order or engineer-to-order companies. These firms have to cope with a high variety of customised products, and strong pressure to provide short throughput times. POLCA constrains the amount of work in progress on the shop floor in order to

  2. Controller design approach based on linear programming.

    Science.gov (United States)

    Tanaka, Ryo; Shibasaki, Hiroki; Ogawa, Hiromitsu; Murakami, Takahiro; Ishida, Yoshihisa

    2013-11-01

    This study explains and demonstrates the design method for a control system with a load disturbance observer. Observer gains are determined by linear programming (LP) in terms of the Routh-Hurwitz stability criterion and the final-value theorem. In addition, the control model has a feedback structure, and feedback gains are determined to be the linear quadratic regulator. The simulation results confirmed that compared with the conventional method, the output estimated by our proposed method converges to a reference input faster when a load disturbance is added to a control system. In addition, we also confirmed the effectiveness of the proposed method by performing an experiment with a DC motor.

  3. Basic design of beamline and polarization control

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The basic concept of synchrotron radiation beamlines for vacuum ultraviolet and X-ray experiments has been introduced to beginning users and designers of beamlines. The beamline defined here is composed of a front end,pre-mirrors, and a monochromator with refocusing mirrors, which are connected by beam pipes, providing monochromatic light for the experiments. Firstly, time characteristics of the synchrotron radiation are briefly reviewed.Secondly, the basic technology is introduced as the fundamental knowledge required to both users and designers. The topics are photoabsorption by air and solids, front ends and beam pipes, mirrors, monochromators, and filters. Thirdly,the design consideration is described mainly for the designers. The topics are design principle, principle of ray tracing,optical machinery and control, and vacuum. Fourthly, polarization control is considered. The topics are polarizers,polarization diagnosis of beamline, and circularly-polarized light generation. Finally, a brief summary is given introducing some references for further knowledge of the users and the designers.

  4. Designing MPC controllers by reverse-engineering existing LTI controllers

    CERN Document Server

    Hartley, Edward N

    2011-01-01

    This technical report presents a method for designing a constrained output-feedback model predictive controller (MPC) that behaves in the same way as an existing baseline stabilising linear time invariant output-feedback controller when constraints are inactive. The baseline controller is cast into an observer-compensator form and an inverse-optimal cost function is used as the basis of the MPC controller. The available degrees of design freedom are explored, and some guidelines provided for the selection of an appropriate observer-compensator realisation that will best allow exploitation of the constraint-handling and redundancy management capabilities of MPC. Consideration is given to output setpoint tracking, and the method is demonstrated with three different multivariable plants of varying complexity.

  5. Design of Dependable Control System Using a Component Based Approach

    DEFF Research Database (Denmark)

    Blanke, M.

    1995-01-01

    Design of fault handling in control systems is discussed and a consistent method for design is presented.......Design of fault handling in control systems is discussed and a consistent method for design is presented....

  6. Use of self-assembled monolayers to control interface bonding in a model study of interfacial fracture

    Energy Technology Data Exchange (ETDEWEB)

    KENT,MICHAEL S.; YIM,HYUN; MATHESON,AARON J.; COGDILL,C.; REEDY JR.,EARL DAVID

    2000-03-02

    The relationship between the nature and spatial distribution of fundamental interfacial interactions and fracture stress/fracture toughness of a glassy adhesive-inorganic solid joint is not understood. This relationship is important from the standpoint of designing interfacial chemistry sufficient to provide the level of mechanical strength required for a particular application. In addition, it is also important for understanding the effects of surface contamination. Different types of contamination, or different levels of contamination, likely impact joint strength in different ways. Furthermore, the relationship is also important from the standpoint of aging. If interfacial chemical bonds scission over time due to the presence of a contaminant such as water, or exposure to UV, etc, the relationship between joint strength/fracture toughness and interface strength is important for predicting reliability with time. A fundamental understanding of the relationship between joint strength and fundamental interfacial interactions will give insight into these issues.

  7. CV controls from design to operation

    CERN Document Server

    Blanc, D

    2002-01-01

    The cooling and Ventilation (CV) group has emphasised the need to redefine its organisational structure at the end of 98. The main objective of this operation was to ensure the CV group to be more competitive and efficient through the growing tasks of the LHC projects. The main evolution given to this reorganisation is that the new structure is more project oriented and then operates on three distinct axes: Design, Work and Operation. Process control project management requires a complete and early interaction and participation of all the actors involved. This procedure to be efficient and constructive must be considered and performed not only during the design stage but along the project planning phases and must go beyond the completion work including the process control operation activity. The paper explains the present project management for process control. It describes the present constraints and gives suggestions to a different approach to these projects to improve performances and efficiency of a contr...

  8. System identification for robust control design

    Energy Technology Data Exchange (ETDEWEB)

    Dohner, J.L.

    1995-04-01

    System identification for the purpose of robust control design involves estimating a nominal model of a physical system and the uncertainty bounds of that nominal model via the use of experimentally measured input/output data. Although many algorithms have been developed to identify nominal models, little effort has been directed towards identifying uncertainty bounds. Therefore, in this document, a discussion of both nominal model identification and bounded output multiplicative uncertainty identification will be presented. This document is divided into several sections. Background information relevant to system identification and control design will be presented. A derivation of eigensystem realization type algorithms will be presented. An algorithm will be developed for calculating the maximum singular value of output multiplicative uncertainty from measured data. An application will be given involving the identification of a complex system with aliased dynamics, feedback control, and exogenous noise disturbances. And, finally, a short discussion of results will be presented.

  9. Sun Safe Mode Controller Design for LADEE

    Science.gov (United States)

    Fusco, Jesse C.; Swei, Sean S. M.; Nakamura, Robert H.

    2015-01-01

    This paper presents the development of sun safe controllers which are designed to keep the spacecraft power positive and thermally balanced in the event an anomaly is detected. Employed by NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE), the controllers utilize the measured sun vector and the spacecraft body rates for feedback control. To improve the accuracy of sun vector estimation, the least square minimization approach is applied to process the sensor data, which is proven to be effective and accurate. To validate the controllers, the LADEE spacecraft model engaging the sun safe mode was first simulated and then compared with the actual LADEE orbital fight data. The results demonstrated the applicability of the proposed sun safe controllers.

  10. Automated design of controlled diffusion blades

    Science.gov (United States)

    Sanz, Jose M.

    1989-01-01

    A numerical automation procedure was developed to be used in conjunction with an inverse hodograph method for the design of controlled diffusion blades. With this procedure a cascade of airfoils with a prescribed solidity, inlet Mach No., inlet air flow angle and air flow turning can be produced automatically. The trailing edge thickness of the airfoil, an important quantity in inverse methods, is also prescribed. The automation procedure consists of a multi-dimensional Newton iteration in which the objective design conditions are achieved by acting on the hodograph input parameters of the underlying inverse code. The method, although more general in scope, is applied to the design of axial flow turbomachinery blade sections, both compressors and turbines. A collaborative effort with U.S. Engine Companies to identify designs of interest to the industry will be described.

  11. HETDEX tracker control system design and implementation

    Science.gov (United States)

    Beno, Joseph H.; Hayes, Richard; Leck, Ron; Penney, Charles; Soukup, Ian

    2012-09-01

    To enable the Hobby-Eberly Telescope Dark Energy Experiment, The University of Texas at Austin Center for Electromechanics and McDonald Observatory developed a precision tracker and control system - an 18,000 kg robot to position a 3,100 kg payload within 10 microns of a desired dynamic track. Performance requirements to meet science needs and safety requirements that emerged from detailed Failure Modes and Effects Analysis resulted in a system of 13 precision controlled actuators and 100 additional analog and digital devices (primarily sensors and safety limit switches). Due to this complexity, demanding accuracy requirements, and stringent safety requirements, two independent control systems were developed. First, a versatile and easily configurable centralized control system that links with modeling and simulation tools during the hardware and software design process was deemed essential for normal operation including motion control. A second, parallel, control system, the Hardware Fault Controller (HFC) provides independent monitoring and fault control through a dedicated microcontroller to force a safe, controlled shutdown of the entire system in the event a fault is detected. Motion controls were developed in a Matlab-Simulink simulation environment, and coupled with dSPACE controller hardware. The dSPACE real-time operating system collects sensor information; motor commands are transmitted over a PROFIBUS network to servo amplifiers and drive motor status is received over the same network. To interface the dSPACE controller directly to absolute Heidenhain sensors with EnDat 2.2 protocol, a custom communication board was developed. This paper covers details of operational control software, the HFC, algorithms, tuning, debugging, testing, and lessons learned.

  12. INNOVATIVE METHODOLOGY FOR DETECTION OF FRACTURE-CONTROLLED SWEET SPOTS IN THE NORTHERN APPALACHIAN BASIN

    Energy Technology Data Exchange (ETDEWEB)

    Robert Jacobi; John Fountain

    2002-01-30

    In the structure task, we completed reducing the data we had collected from a N-S transect on the east of Seneca Lake. We have calculated the fracture frequency for all the fracture sets at each site, and constructed modified rose diagrams that summarize the fracture attributes at each site. These data indicate a N-striking fault near the southeastern shore of Seneca Lake, and also indicate NE and ENE-trending FIDs and faults north of Valois. The orientation and existence of the ENE-striking FIDs and faults are thought to be guided by faults in the Precambrian basement; these basement faults apparently were sufficiently reactivated to cause faulting in the Paleozoic section. Other faults are thrust ramps above the Silurian salt section that were controlled by a far-field Alleghanian stress field. Structure contour maps and isopach maps have been revised based on additional well log analyses. Except for the Glodes Corners Field, the well spacing generally is insufficient to definitively identify faults. However, relatively sharp elevational changes east of Keuka Lake support the contention that faults occur along the east side of Keuka Lake. Outcrop stratigraphy along the east side of Seneca Lake indicates that faults and gentle folds can be inferred from the some exposures along Seneca Lake, but the lensing nature of the individual sandstones can preclude long-distance definitive correlations and structure identification. Soil gas data collected during the 2000 field season was reduced and displayed in the previous semiannual report. The seismic data that Quest licensed has been reprocessed. Several grabens observed in the Trenton reflector are consistent with surface structure, soil gas, and aeromagnetic anomalies. In this report we display an interpreted seismic line that crosses the Glodes Corners and Muck Farm fields. The final report from the subcontractor concerning the completed aeromagnetic survey is included. Prominent magnetic anomalies suggest that

  13. The impact of depot medroxyprogesterone acetate on fracture risk: a case-control study from the UK.

    Science.gov (United States)

    Kyvernitakis, I; Kostev, K; Nassour, T; Thomasius, F; Hadji, P

    2017-01-01

    There has been concerning about women receiving depot medroxyprogesterone acetate (DMPA) contraception because of the prolonged hypoestrogenemic state regarding the potential negative effects on bone health. This study showed that DMPA exposure is associated with increased fracture risk and that fracture risk increases with longer DMPA exposure. DMPA has been associated with impaired bone mineral acquisition during adolescence and accelerated bone loss in later life. We performed this large population-based study to assess the association between use of DMPA or combined oral contraceptives and the incident risk of fracture. We identified 4189 women between 20 and 44 years of age with a first-time fracture diagnosis, matched them with 4189 random controls using the Disease Analyzer database and investigated the relation with DMPA exposure. Overall, 11 % of the fracture cases and 7.7 % of the controls had DMPA use recorded. The adjusted OR for developing a fracture in patients with current use of DMPA compared to non-users was 0.97 (95 % CI 0.51-1.86), 2.41 (95 % CI 1.42-4.08), and 1.46 (95 % CI 0.96-2.23) for 1-2, 3-9, and ≥10 prescriptions, respectively. The adjusted OR for developing a fracture in patients with past use of DMPA compared to non-users was 0.96 (95 % CI 0.73-1.26), 1.14 (95 % CI 0.86-1.51), and 1.55 (95 % CI 1.07-2.27) for 1-2, 3-9, and ≥10 prescriptions, respectively. The highest fracture risk was identified in young patients less than 30 years with longer DMPA exposure (≥10 prescriptions; OR 3.04, 95 % CI 1.36-6.81), as well as in patients in the late reproductive years with past use of DMPA (OR 1.72, 95 % CI 1.13-2.63). Our results indicate that DMPA exposure is associated with increased fracture risk and may have negative effects on bone metabolism, resulting in impaired bone mineral acquisition during adolescence and accelerated bone loss in adult life.

  14. Design of Air Traffic Control Operation System

    Directory of Open Access Journals (Sweden)

    Gabriela STROE

    2017-09-01

    Full Text Available This paper presents a numerical simulation for a different aircraft, based on the specific aircraft data that can be incorporated in the model and the equations of motions which can be consequently solved. The aircraft flight design involves various technical steps and requires the use of sophisticated software having modeling and simulation capabilities. Within the flight simulation model, the aerodynamic model can be regarded as the most complex and most important. With appropriate aerodynamic modeling the aerodynamic forces and moments acting on the aircraft's center of gravity can be numerically solved with accuracy. These forces and moments are further used to solve the equations of motion. The development of control and computing technology makes it possible for advanced flight control strategy. The advanced control techniques tend to make the control design and their implementation much more complicated with more control loops or channels; in this line, the autopilot of modern aircrafts includes a variety of automatic control systems that aid and support the flight navigation, flight management, and perform the enhancing and/or augmenting of the stability characteristics of the airplane. Therefore in this context it is very important to choose the dynamic that will satisfy the performance and robustness specifications.

  15. Design of PI Controllers for Hydraulic Control Systems

    Directory of Open Access Journals (Sweden)

    LJubiša Dubonjić

    2013-01-01

    Full Text Available The paper proposes a procedure for design of PI controllers for hydraulic systems with long transmission lines which are described by models of high order. Design is based on the combination of the IE criterion and engineering specifications (settling time and relative stability as well as on the application of D-decomposition. In comparison with some known results, the method is of graphical character, and it is very simple (solving nonlinear algebraic equations is eliminated. The paper presents the algorithm of software procedure for design of the controller. The method is compared with other methods at the level of simulation, and its superiority is shown. By applying the Nyquist criterion, it is shown that the method possesses robustness in relation to non modelled dynamics.

  16. Designing, Assessing, and Demonstrating Sustainable Bioaugmentation for Treatment of DNAPL Sources in Fractured Bedrock

    Science.gov (United States)

    2017-03-27

    exacerbated by the complexities associated with the dual porosity nature of fractured rock, as well as the lack of insight into the highly complex DNAPL...cellular-based telemetry system. The SCADA/PLC enables the application of power to the pneumatic pump solenoid valves and chemical feed pump, and also

  17. The design of image stabilization control system

    Science.gov (United States)

    Lin, Zhe; Wu, Chunnan; Yu, Fei; Kang, Xiaojun

    2012-09-01

    For high resolution satellite remote sensing cameras, the line of sight (LOS) moving during the image exposure period will cause the modulation transfer function (MTF) degradation and image blurring. Image stabilization component is used to improve image quality by actively removing the apparent motion induced by vibration, tracking error and attitude instability. In this paper, the image stabilization component is considered as a kind of closed loop servo control system, and the image stabilization effect is converted into servo control performance for research. Firstly, the image stabilization servo loop scheme and transfer function model are constructed and the LOS jitter is considered as the output of a stochastic system derived by white-Gaussian noise. Based on the proposed model, the demand boundary of jitter rejection function is described, and the design criterion to be satisfied is obtained according to the requirement of image stabilization performance. And then, a discrete Kalman estimation algorithm is introduced into image stabilization servo loop to filter out the noise caused by pixel-shift sensor (PSS) and compensate for the delay due to the PSS measurement. Based on the given design criterion, the control law is designed by using the output of Kalman filter. The computer simulation is achieved to show that the proposed control strategy can significantly improve the image stabilization performance.

  18. Analgesic effect of salmon calcitonin in osteoporotic vertebral fractures: a double-blind placebo-controlled clinical study.

    Science.gov (United States)

    Lyritis, G P; Tsakalakos, N; Magiasis, B; Karachalios, T; Yiatzides, A; Tsekoura, M

    1991-12-01

    Back pain due to vertebral collapse is the main symptom of postmenopausal osteoporosis. The clinical picture in these crush fractures varies, depending on the type and the location of fracture, but in general, a new vertebral crush fracture gives rise to severe pain that immobilizes the patient and necessitates bedrest. In this double-blind controlled clinical trial, 56 patients who had recently (within the last 3 days) suffered an osteoporotic vertebral fracture were hospitalized for a period of 14 days. Salmon calcitonin (100 IU) or placebo injections were given daily. Pain was rated daily on a 10-point scale by the same observers. Blood and urinary parameters were also evaluated. The results showed a significant (P less than 0.001) difference in pain intensity between the calcitonin group and the placebo group. This beneficial effect was generally apparent from the second day of treatment onward, and over the following 2 weeks, the patients were able to sit and stand, and gradually started to walk again. A significant decrease in urinary hydroxyproline and urinary calcium was also noted in the calcitonin group. It is concluded that calcitonin exerts a beneficial effect on back pain following a vertebral crush fracture.

  19. Odds ratios for hip- and lower forearm fracture using peripheral bone densitometry; a case-control study of postmenopausal women

    DEFF Research Database (Denmark)

    Saleh, M M A; Jørgensen, H L; Lauritzen, J B

    2002-01-01

    BACKGROUND: Dual-energy X-ray absorptiometry (DXA) measured at the lumbar spine and particularly at the hip remain the gold-standard for diagnosing osteoporosis. However, devices for assessing the peripheral skeleton present several advantages in terms of lower price and portability. A major...... concern when using peripheral densitometry is the poor correlation with the central measurements. The main aim of this study is, therefore, to assess the possibility of expressing ultrasound measurements at the heel and bone mineral density (BMD) measured at the distal forearm as fracture odds ratios...... scanner as well as BMD measured by dual X-ray absorptiometry on the DTX-200 at the distal forearm. RESULTS: BUA, SOS and BMD at the distal forearm were all significantly lower in fracture patients compared with their respective control groups. The odds ratio for lower forearm fracture was 3.1 (95% CI: 1...

  20. A Biomechanical Study Comparing Helical Blade with Screw Design for Sliding Hip Fixations of Unstable Intertrochanteric Fractures

    Directory of Open Access Journals (Sweden)

    Qiang Luo

    2013-01-01

    Full Text Available Dynamic hip screw (DHS is a well-established conventional implant for treating intertrochanteric fracture. However, revision surgery sometimes still occurs due to the cutting out of implants. A helical blade instead of threaded screw (DHS blade was designed to improve the fixation power of the osteoporotic intertrochanteric fracture. In this study, the biomechanical properties of DHS blade compared to the conventional DHS were evaluated using an unstable AO/OTA 31-A2 intertrochanteric fracture model. Fifty synthetic proximal femoral bone models with such configuration were fixed with DHS and DHS blade in five different positions: centre-centre (CC, superior-centre (SC, inferior-center (IC, centre-anterior (CA, and centre-posterior (CP. All models had undergone mechanical compression test, and the vertical and rotational displacements were recorded. The results showed that DHS blade had less vertical or rotational displacement than the conventional DHS in CC, CA, and IC positions. The greatest vertical and rotational displacements were found at CP position in both groups. Overall speaking, DHS blade was superior in resisting vertical or rotational displacement in comparison to conventional DHS, and the centre-posterior position had the poorest performance in both groups.

  1. Quantitative resilience analysis through control design.

    Energy Technology Data Exchange (ETDEWEB)

    Sunderland, Daniel; Vugrin, Eric D.; Camphouse, Russell Chris (Sandia National Laboratories, Carlsbad, NM)

    2009-09-01

    Critical infrastructure resilience has become a national priority for the U. S. Department of Homeland Security. System resilience has been studied for several decades in many different disciplines, but no standards or unifying methods exist for critical infrastructure resilience analysis. Few quantitative resilience methods exist, and those existing approaches tend to be rather simplistic and, hence, not capable of sufficiently assessing all aspects of critical infrastructure resilience. This report documents the results of a late-start Laboratory Directed Research and Development (LDRD) project that investigated the development of quantitative resilience through application of control design methods. Specifically, we conducted a survey of infrastructure models to assess what types of control design might be applicable for critical infrastructure resilience assessment. As a result of this survey, we developed a decision process that directs the resilience analyst to the control method that is most likely applicable to the system under consideration. Furthermore, we developed optimal control strategies for two sets of representative infrastructure systems to demonstrate how control methods could be used to assess the resilience of the systems to catastrophic disruptions. We present recommendations for future work to continue the development of quantitative resilience analysis methods.

  2. Evaluation of Design Methods for Geometric Control

    DEFF Research Database (Denmark)

    Kymmel, Mogens; Beran, M.; Foldager, L.;

    1985-01-01

    Geometric control can produce desirable control by decoupling the input disturbances from the selected output variables. The basic principle for this method was originally introduced by Wonham. The mathematical complexity involved, however, makes the method very hard to get accepted by the chemical...... community. The paper evaluates Wonham's original method together with three other methods, i.e. eigenvalue/eigenvector methods by Shah et al, the graph theory by Schizas and Evans and the simplified method by Kümmel et al. The evaluation considers the basic potential of the methods, the prerequisite...... of the designer, transparency, computer demand, and potential for pole shift....

  3. Designer's handbook of instrumentation and control circuits

    CERN Document Server

    Carr, Joseph J

    1991-01-01

    Here is a comprehensive, practical guide to the entire process of analog instrumentation and control, from sensor input to data conversion circuitry and final output. This readable handbook avoids complex mathematical treatments, instead taking an applications-oriented approach and presenting many sample circuits and concrete examples. It is an essential reference for engineers and high-level technicians in a variety of scientific and engineering fields--anywhere data is collected electronically and where such data is used to control physical processes.Key Features* Covers design o

  4. Design and control of swarm dynamics

    CERN Document Server

    Bouffanais, Roland

    2016-01-01

    The book is about the key elements required for designing, building and controlling effective artificial swarms comprised of multiple moving physical agents. Therefore this book presents the fundamentals of each of those key elements in the particular frame of dynamic swarming, specifically exposing the profound connections between these elements and establish some general design principles for swarming behaviors. This scientific endeavor requires an inter-disciplinary approach: biomimetic inspiration from ethology and ecology, study of social information flow, analysis of temporal and adaptive signaling network of interaction, considerations of control of networked real-time systems, and lastly, elements of complex adaptive dynamical systems. This book offers a completely new perspective on the scientific understanding of dynamic collective behaviors thanks to its multi-disciplinary approach and its focus on artificial swarm of physical agents. Two of the key problems in understanding the emergence of swarm ...

  5. Hospital design for better infection control

    Directory of Open Access Journals (Sweden)

    Lateef Fatimah

    2009-01-01

    Full Text Available The physical design and infrastructure of a hospital or institution is an essential component of its infection control measure. Thus is must be a prerequisite to take these into consideration from the initial conception and planning stages of the building. The balance between designing a hospital to be an open, accessible and public place and the control to reduce the spread of infections diseases is a necessity. At Singapore General Hospital, many lessons were learnt during the SARS outbreak pertaining to this. During and subsequent to the SARS outbreak, many changes evolved in the hospital to enable us to handle and face any emerging infectious situation with calm, confidence and the knowledge that staff and patients will be in good stead. This paper will share some of our experiences as well as challenges

  6. Automated design of controlled-diffusion blades

    Science.gov (United States)

    Sanz, J. M.

    1988-01-01

    A numerical automation procedure has been developed to be used in conjunction with an inverse hodograph method for the design of controlled diffusion blades. With this procedure a cascade of airfoils with a prescribed solidity, inlet Mach number, inlet air flow angle, and air flow turning can be produced automatically. The trailing edge thickness of the airfoil, an important quantity in inverse methods, is also prescribed. The automation procedure consists of a multidimensional Newton iteration in which the objective design conditions are achieved by acting on the hodograph input parameters of the underlying inverse code. The method, although more general in scope, is applied in this paper to the design of axial flow compressor blade sections, and a wide range of examples is presented.

  7. Computational Methods for Design, Control and Optimization

    Science.gov (United States)

    2007-10-01

    34scenario" that applies to channel flows ( Poiseuille flows , Couette flow ) and pipe flows . Over the past 75 years many complex "transition theories" have...other areas of flow control, optimization and aerodynamic design. approximate sensitivity calculations and optimization codes. The effort was built on a...for fluid flow problems. The improved robustness and computational efficiency of this approach makes it practical for a wide class of problems. The

  8. Controller Design Considerations for ACM APFC Systems

    Directory of Open Access Journals (Sweden)

    Alexander Abramovitz

    2012-01-01

    Full Text Available This paper is concerned with performance of the current shaping network in Average Current Mode (ACM Active Power Factor Correction (APFC systems. Theoretical expressions for the ripple components are derived. Then, ripple interaction and impact on the current loop reference signal are investigated. A modification of the controller network is suggested that results in an improved Total Harmonic Distortion (THD. Design guidelines are suggested. The theoretical predictions were validated by simulation.

  9. Fracturing fluid cleanup by controlled release of enzymes from polyelectrolyte complex nanoparticles

    Science.gov (United States)

    Barati Ghahfarokhi, Reza

    activity of enzymes by entrapping them. It was also observed that control PEC nanoparticles decreased both viscoelastic moduli, but with a slower rate compared to the PEC nanoparticles loaded with enzyme. Preparation shear and applied shear showed no significant effect on activity of enzyme-loaded PEC nanoparticles mixed with HPG solutions. However, fast addition of chemicals during the preparations showed smaller particle size compared to the drop-wise method. PEC nanoparticles (PECNPs) also protected both enzymes from denaturation at elevated temperature and pH. Following preparation, enzyme-loaded PEC nanoparticles were mixed with borate crosslinked HPG and the mixture was injected through a shear loop. Pectinase-loaded nanoparticles mixed with gelled HPG showed no sensitivity to shear applied along the shear loop at 25 °C. However, EL2X-loaded PEC nanoparticles showed sensitivity to shear applied along the shear loop at 40 °C. Filter cake was formed and degraded in a fluid loss cell for borate crosslinked HPG solutions mixed with either enzymes or enzyme-loaded PEC nanoparticles. Cleanup slopes of filter cake degraded using enzyme-loaded PEC nanoparticles and systems with enzymes mixed with HPG gel were significantly higher than for the filter cake formed with HPG gel mixed with no enzyme. In a different application, enzyme-loaded PEC nanoparticles showed significantly slower reduction in viscosity of HPG solution over time compared to the HPG systems mixed with enzyme. Increasing the viscosity of low concentration HPG, used as slick-water, decreases the proppant settling velocity. This is of specific interest in fracturing fluids used for unconventional reservoirs.

  10. Fascia iliaca compartment blockade for acute pain control in hip fracture patients

    DEFF Research Database (Denmark)

    Foss, Nicolai B; Kristensen, Billy B; Bundgaard, Morten

    2007-01-01

    Hip fracture patients are in severe pain upon arrival at the emergency department. Pain treatment is traditionally based on systemic opioids. No study has examined the effect of fascia iliaca compartment blockade (FICB) in acute hip fracture pain management within a double-blind, randomized setup....

  11. Closed patella fracture combined with cruciate ligament injury:a case control study

    Institute of Scientific and Technical Information of China (English)

    LI Han; WANG Wei; LIU Yue-ju; CHEN Wei; ZHANG Qi; LI Xu; ZHU Lian

    2013-01-01

    Background Patellar fracture and cruciate ligament injury are a common consequence of traumatic knee injury.Patellar fracture combined with cruciate ligament injury is rarely reported,although the mechanisms of two things are similar.This study aimed to evaluate the incidence of closed patella fracture combined with cruciate ligament injury.Methods From 2012 March 1 to June 30,magnetic resonance images of 60 patients with unilateral closed patellar fracture were studied in our institution.The mean age of the patients at presentation was 40.2 years (range,13-64 years) and 48 patients were men.First,patients were divided according to the cause of injury.Twenty-eight patients had highenergy trauma from a falling injury or motor vehicle accident,and 32 patients had low-energy trauma resulting from a tumbling injury.Second,according to the fracture pattern,31 patients had a transverse fracture and 29 patients had a comminuted fracture.Results We found seven cases of closed patellar fracture combined with cruciate ligament injury among 60 patients,including two cases of a completely ruptured posterior cruciate ligament,two with a partially torn posterior cruciate ligament,and three with a partially torn anterior cruciate ligament.The percentage of this combined injury was 11.6% (7/60).The incidence of a combined injury of the cruciate ligament with a comminuted fracture (6/29,20.7%) was significantly higher than that with a transverse fracture (1/31,3.2%,P <0.05).The most common mechanism of injury in patellar fracture combined with cruciate ligament injury was high-energy trauma from road traffic accidents (94%),whereas in the patellar fracture alone,it was tumbling (62%).The incidence of combined injury with high-energy trauma (6/28,21.4%) was significantly higher than that with low-energy trauma (1/32,3.1%,P <0.05).Conclusions These data suggest that high-energy trauma often results in a comminuted patellar fracture,which is often combined with

  12. Posterior paramedian subrhomboidal analgesia versus thoracic epidural analgesia for pain control in patients with multiple rib fractures.

    Science.gov (United States)

    Shelley, Casey L; Berry, Stepheny; Howard, James; De Ruyter, Martin; Thepthepha, Melissa; Nazir, Niaman; McDonald, Tracy; Dalton, Annemarie; Moncure, Michael

    2016-09-01

    Rib fractures are common in trauma admissions and are associated with an increased risk of pulmonary complications, intensive care unit admissions, and mortality. Providing adequate pain control in patients with multiple rib fractures decreases the risk of adverse events. Thoracic epidural analgesia is currently the preferred method for pain control. This study compared outcomes in patients with multiple acute rib fractures treated with posterior paramedian subrhomboidal (PoPS) analgesia versus thoracic epidural analgesia (TEA). This prospective study included 30 patients with three or more acute rib fractures admitted to a Level I trauma center. Thoracic epidural analgesia or PoPS catheters were placed, and local anesthesia was infused. Data were collected including patients' pain level, adjunct morphine equivalent use, adverse events, length of stay, lung volumes, and discharge disposition. Nonparametric tests were used and two-sided p Pain rating was lower in the PoPS group (2.5 vs. 5; p = 0.03) after initial placement. Overall, there was no other statistically significant difference in pain control or use of oral morphine adjuncts between the groups. Hypotension occurred in eight patients, 75% with TEA and only 25% with PoPS. No difference was found in adverse events, length of stay, lung volumes, or discharge disposition. In patients with rib fractures, PoPS analgesia may provide pain control equivalent to TEA while being less invasive and more readily placed by a variety of hospital staff. This pilot study is limited by its small sample size, and therefore additional studies are needed to prove equivalence of PoPS compared to TEA. Therapeutic study, level IV.

  13. Risk factors for falls with severe fracture in elderly people living in a middle-income country: a case control study

    Directory of Open Access Journals (Sweden)

    Bloch Katia V

    2008-08-01

    Full Text Available Abstract Background Fracture after falling has been identified as an important problem in public health. Most studies of risk factors for fractures due to falls have been carried out in developed countries, although the size of the elderly population is increasing fast in middle income countries. The objective of this paper is to identify risk factors for fall related to severe fractures in those aged 60 or more in a middle-income country. Methods A case-control study was carried out in Rio de Janeiro-Brazil based general hospitals between 2002–2003. Two hundred-fifty hospitalised cases of fracture were matched with 250 community controls by sex, age group and living area. Data were collected for socio-demographic variables, health status and drugs used before the fall. A conditional logistic regression model was fitted to identify variables associated with the risk of fall related severe fracture. Results Low body mass index, cognitive impairment, stroke and lack of urine control were associated with increased risk of severe fall related fractures. Benzodiazepines and muscle relaxants were also related to an increased risk of severe fractures while moderate use of alcohol was associated with reduced risk. Conclusion Although the association between benzodiazepines and fractures due to fall has been consistently demonstrated for old people, this has not been the case for muscle relaxant drugs. The decision to prescribe muscle relaxants for elderly people should take into account the risk of severe fracture associated with these drugs.

  14. INNOVATIVE METHODOLOGY FOR DETECTION OF FRACTURE-CONTROLLED SWEET SPOTS IN THE NORTHERN APPALACHIAN BASIN

    Energy Technology Data Exchange (ETDEWEB)

    Robert Jacobi; John Fountain

    2001-02-28

    In the structure task, we completed a N-S transect east of Seneca Lake that indicated a N-striking fault near the southeastern shore of Seneca Lake, and also indicated NE and ENE-trending FIDs and faults north of Valois. The orientation and existence of the NE-striking FIDs and faults are thought to be controlled by basement faults, rather than thrust ramps above the Salina salt controlled only by a far-field Alleghanian stress field. Structure contour maps based on well log analyses have been constructed but not interpreted. Soil gas data displayed a number of ethane-charged soil gas ''spikes'' on a N-S transect from Ovid south to near Valois. The soil gas team found a larger number of spikes in the northern half of the survey, suggesting more open fractures (and faults) in the northern half of the survey. Seismic data has been purchased and reprocessed. Several grabens observed in the Trenton reflector are consistent with surface structure, soil gas, and aeromagnetic anomalies. The aeromagnetic survey is completed and the data is processed. Prominent magnetic anomalies suggest that faults in the Precambrian basement are located beneath regions where grabens in the Trenton are located.

  15. Advanced Control Design for Wind Turbines; Part I: Control Design, Implementation, and Initial Tests

    Energy Technology Data Exchange (ETDEWEB)

    Wright, A. D.; Fingersh, L. J.

    2008-03-01

    The purpose of this report is to give wind turbine engineers information and examples of the design, testing through simulation, field implementation, and field testing of advanced wind turbine controls.

  16. Shot count reduction for non-Manhattan geometries: concurrent optimization of data fracture and mask writer design

    Science.gov (United States)

    Cinque, Russell; Komagata, Tadashi; Kiuchi, Taiichi; Browning, Clyde; Schiavone, Patrick; Petroni, Paolo; Martin, Luc; Quaglio, Thomas

    2013-09-01

    VSB mask writers, which create patterns using a combination of rectangles and 45 degree triangles, are ill-suited to non- Manhattan geometries. This issue is particularly acute for layouts which contain a large fraction of curvilinear "offangle" patterns such as photonic or DRAM designs. Unable to faithfully reproduce the "off-angle" structures, traditional VSB mask writers approximate the desired design using abutted rectangular shots or small shapes to smooth out line edge roughness. Fidelity to the original pattern comes at a cost of increased shot count and reduced throughput. Aselta has developed a novel fracture algorithm to dramatically reduce the shot count of such designs. Using a traditional VSB pattern generator, the new algorithm provides significant shot count reduction. When combined with a modified JBX-3200MV VSB, the shot count is reduced while maintaining the same level of fidelity. The data preparation software tool has also the capability of trading off a more accurate level of fidelity with an even more reduced shot count. The paper will first describe the basic principles of the fracturing algorithm and e-beam writer hardware configuration then demonstrate the advantage of the method on a variety of patterns.

  17. Designing hydrogels for controlled drug delivery

    Science.gov (United States)

    Li, Jianyu; Mooney, David J.

    2016-12-01

    Hydrogel delivery systems can leverage therapeutically beneficial outcomes of drug delivery and have found clinical use. Hydrogels can provide spatial and temporal control over the release of various therapeutic agents, including small-molecule drugs, macromolecular drugs and cells. Owing to their tunable physical properties, controllable degradability and capability to protect labile drugs from degradation, hydrogels serve as a platform on which various physiochemical interactions with the encapsulated drugs occur to control drug release. In this Review, we cover multiscale mechanisms underlying the design of hydrogel drug delivery systems, focusing on physical and chemical properties of the hydrogel network and the hydrogel-drug interactions across the network, mesh and molecular (or atomistic) scales. We discuss how different mechanisms interact and can be integrated to exert fine control in time and space over drug presentation. We also collect experimental release data from the literature, review clinical translation to date of these systems and present quantitative comparisons between different systems to provide guidelines for the rational design of hydrogel delivery systems.

  18. Zolpidem Use and Risk of Fracture in Elderly Insomnia Patients

    OpenAIRE

    Kang, Dong-Yoon; Park, Soyoung; Rhee, Chul-Woo; Kim, Ye-Jee; Choi, Nam-Kyong; Lee, Joongyub; Park, Byung-Joo

    2012-01-01

    Objectives To evaluate the risk of fractures related with zolpidem in elderly insomnia patients. Methods Health claims data on the entire South Korean elderly population from January 2005 to June 2006 were extracted from the Health Insurance Review and Assessment Service database. We applied a case-crossover design. Cases were defined as insomnia patients who had a fracture diagnosis. We set the hazard period of 1 day length prior to the fracture date and four control periods of the same leng...

  19. Design of computer controlled combustion engines

    Energy Technology Data Exchange (ETDEWEB)

    Isermann, R.; Mueller, N. [Darmstadt University of Technology (Germany). Inst. of Automatic Control

    2003-12-01

    Globalization and growing new markets, as well as increasing emission and fuel consumption requirements, force the car manufacturers and their suppliers to develop new engine control strategies in shorter time periods. This can mainly be reached by development tools and an integrated hardware and software environment enabling rapid implementation and testing of advanced engine control algorithms. The structure of a rapid control prototyping (RCP) system is explained, which allows fast measurement signal evaluation, and rapid prototyping of advanced engine control algorithms. A hardware-in-the-loop simulator for diesel engine control design is illustrated, simulation results for a 40 tons truck are presented. Providing efficient engine models for the proposed development tools, a dynamic local linear neural network approach is explained and applied for modelling the NO{sub x} emission characteristics of a 1.9 1 direct injection diesel engine. Furthermore the application of a RCP system is exemplified by the application of combustion pressure based closed-loop ignition timing control for a SI engine. Experimental results are shown for a 1.01 SI engine on a dynamic engine test stand. (author)

  20. Designing, Assessing, and Demonstrating Sustainable Bioaugmentation for Treatment of DNAPL Sources in Fractured Bedrock

    Science.gov (United States)

    2017-01-27

    dual porosity nature of fractured rock, as well as the lack of insight into the highly complex DNAPL architecture at the field scale. The work...monitor and regulate the operation of the various system components, both locally and remotely through a cellular-based telemetry system. The SCADA/PLC...head (right). The acoustic televiewer transmits ultrasonic pulses from a rotating sensor (mirror) and records the signals reflected from the

  1. Displaced midshaft fractures of the clavicle: non-operative treatment versus plate fixation (Sleutel-TRIAL. A multicentre randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Vos Dagmar I

    2011-08-01

    Full Text Available Abstract Background The traditional view that the vast majority of midshaft clavicular fractures heal with good functional outcomes following non-operative treatment may be no longer valid for all midshaft clavicular fractures. Recent studies have presented a relatively high incidence of non-union and identified speciic limitations of the shoulder function in subgroups of patients with these injuries. Aim A prospective, multicentre randomised controlled trial (RCT will be conducted in 21 hospitals in the Netherlands, comparing fracture consolidation and shoulder function after either non-operative treatment with a sling or a plate fixation. Methods/design A total of 350 patients will be included, between 18 and 60 years of age, with a dislocated midshaft clavicular fracture. The primary outcome is the incidence of non-union, which will be determined with standardised X-rays (Antero-Posterior and 30 degrees caudocephalad view. Secondary outcome will be the functional outcome, measured using the Constant Score. Strength of the shoulder muscles will be measured with a handheld dynamometer (MicroFET2. Furthermore, the health-related Quality of Life score (ShortForm-36 and the Disabilities of Arm, Shoulder and Hand (DASH Outcome Measure will be monitored as subjective parameters. Data on complications, bone union, cosmetic aspects and use of painkillers will be collected with follow-up questionnaires. The follow-up time will be two years. All patients will be monitored at regular intervals over the subsequent twelve months (two and six weeks, three months and one year. After two years an interview by telephone and a written survey will be performed to evaluate the two-year functional and mechanical outcomes. All data will be analysed on an intention-to-treat basis, using univariate and multivariate analyses. Discussion This trial will provide level-1 evidence for the comparison of consolidation and functional outcome between two standardised

  2. Design of Controller for New EAST Fast Control Power Supply

    Institute of Scientific and Technical Information of China (English)

    HUANG Haihong; YIN Ming; WANG Haixin

    2014-01-01

    The effectiveness of the magnetic confinement of plasma can be improved by elongating the plasma cross-section in tokamak devices.But elongated plasma has vertical displacement instability,so a feedback control system is needed to restrain the plasma's vertical displacement.A fast control power supply is needed to excite the active feedback coils,which produces a magnetic field to control the plasma's displacement.With the development of EAST,the fast control power supply needs to keep on enhancing the fast response and output current.The structure of a new power supply is introduced in this paper.The method of multiple inverters paralleled with the current sharing reactor is presented to meet the need for large current and fast control.According to the design demands of the EAST fast control power supply,the adjuster of the current close loop is applied to the inverter,which can advance its ability to restrain the loop current in low frequency and DC output.The result of the experiment confirms the validity of the proposed scheme and control strategy.

  3. Solar Power Station Output Inverter Control Design

    Directory of Open Access Journals (Sweden)

    J. Bauer

    2011-04-01

    Full Text Available The photovoltaic applications spreads in these days fast, therefore they also undergo great development. Because the amount of the energy obtained from the panel depends on the surrounding conditions, as intensity of the sun exposure or the temperature of the solar array, the converter must be connected to the panel output. The Solar system equipped with inverter can supply small loads like notebooks, mobile chargers etc. in the places where the supplying network is not present. Or the system can be used as a generator and it shall deliver energy to the supply network. Each type of the application has different requirements on the converter and its control algorithm. But for all of them the one thing is common – the maximal efficiency. The paper focuses on design and simulation of the low power inverter that acts as output part of the whole converter. In the paper the design of the control algorithm of the inverter for both types of inverter application – for islanding mode and for operation on the supply grid – is discussed. Attention is also paid to the design of the output filter that should reduce negative side effects of the converter on the supply network.

  4. MAP Attitude Control System Design and Analysis

    Science.gov (United States)

    Andrews, S. F.; Campbell, C. E.; Ericsson-Jackson, A. J.; Markley, F. L.; ODonnell, J. R., Jr.

    1997-01-01

    The Microwave Anisotropy Probe (MAP) is a follow-on to the Differential Microwave Radiometer (DMR) instrument on the Cosmic Background Explorer (COBE) spacecraft. The MAP spacecraft will perform its mission in a Lissajous orbit around the Earth-Sun L(sub 2) Lagrange point to suppress potential instrument disturbances. To make a full-sky map of cosmic microwave background fluctuations, a combination fast spin and slow precession motion will be used. MAP requires a propulsion system to reach L(sub 2), to unload system momentum, and to perform stationkeeping maneuvers once at L(sub 2). A minimum hardware, power and thermal safe control mode must also be provided. Sufficient attitude knowledge must be provided to yield instrument pointing to a standard deviation of 1.8 arc-minutes. The short development time and tight budgets require a new way of designing, simulating, and analyzing the Attitude Control System (ACS). This paper presents the design and analysis of the control system to meet these requirements.

  5. On the design of chemical processes with improved controllability characteristics

    OpenAIRE

    Meeuse, F.M.

    2003-01-01

    Traditionally, process design and control system design are carried out sequentially. The premise underlying this sequential approach is that the decisions made in the process design phase do not limit the control design. However, it is generally known that incongruent designs can occur quite easily. In the literature two different classes of approaches are being described that consider the control performance of the design alternatives from the earliest design stages: (i) Anticipating sequen...

  6. Conceptual design report for site drainage control

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, M.R.

    1996-07-01

    The Mound Plant (Mound), located in Miamisburg, Ohio, is a Department of Energy (DOE) development and production facility performing support work for DOE`s weapons and energy-related programs. EG&G Mound Applied Technologies, Inc. (EG&G) is the Operating Contractor (OC) for this Government-Owned, Contractor-Operated (GOCO) facility. The work performed at Mound emphasizes nuclear energy and explosives technology. Mound is currently implementing an Environmental, Safety & Health (ES&H) Upgrades Program designed to protect its employees, the public, and the environment from adverse effects caused by facility activities. The first project of this multiphase program is now in the final stages of construction, and the second project is currently under design. Four additional projects, one of which is presented in this report, are in the conceptual design stage. At Mound, 22 soil zones have become contaminated with radioactive material. These zones cover approximately 20 percent of the total area of developed property at the site. During a storm event, the rainwater washes contaminated soil from these zones into the storm sewer system. These radioactive contaminants may then be discharged along with the stormwater into the Great Miami River via the Miami Erie Canal. This conceptual design report (CDR), Site Drainage Control, the fourth project in the ES&H program, describes a project that will provide improvements and much needed repairs to inadequate and deteriorating portions of the storm drainage system on the developed property. The project also will provide a stormwater retention facility capable of storing the stormwater runoff, from the developed property, resulting from a 100-year storm event. These improvements will permit the effective control and monitoring of stormwater to prevent the spread of radioactive contaminants from contaminated soil zones and will provide a means to collect and contain accidental spills of hazardous substances.

  7. Design, fabrication and control of soft robots

    Science.gov (United States)

    Rus, Daniela; Tolley, Michael T.

    2015-05-01

    Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.

  8. Design, fabrication and control of soft robots.

    Science.gov (United States)

    Rus, Daniela; Tolley, Michael T

    2015-05-28

    Conventionally, engineers have employed rigid materials to fabricate precise, predictable robotic systems, which are easily modelled as rigid members connected at discrete joints. Natural systems, however, often match or exceed the performance of robotic systems with deformable bodies. Cephalopods, for example, achieve amazing feats of manipulation and locomotion without a skeleton; even vertebrates such as humans achieve dynamic gaits by storing elastic energy in their compliant bones and soft tissues. Inspired by nature, engineers have begun to explore the design and control of soft-bodied robots composed of compliant materials. This Review discusses recent developments in the emerging field of soft robotics.

  9. Influence of Different Framework Designs on the Fracture Properties of Ceria-Stabilized Tetragonal Zirconia/Alumina-Based All-Ceramic Crowns

    Directory of Open Access Journals (Sweden)

    Tomofumi Sawada

    2016-05-01

    Full Text Available The aim of this study was to evaluate the fracture load and failure mode of all-ceramic crowns with different ceria-stabilized tetragonal zirconia/alumina nanocomposite (Ce-TZP/A framework designs. Four frameworks (anatomical shape: AS, with a buccal or lingual supporting structure: BS and LS, or buccal and lingual supporting structures: BLS were fabricated. All frameworks were veneered with porcelain to fabricate all-ceramic crowns followed by cementation to tooth analogs. The fracture load of each crown either without or with pre-loading (1.2 million cycles, 49 N was measured. The failure mode was classified into partial or complete fracture. Differences were tested for significance (p < 0.05 by a two-way Analysis of Variance (ANOVA, followed by Tukey’s test and by Fisher’s exact test, respectively. Without pre-loading, supporting structures did not influence the fracture load or failure mode. Partial fractures were the most common failure mode. Pre-loading promoted the severity of the failure mode, although the fracture load among the framework designs was not influenced. In the AS group, prefailures were observed during pre-loading, and complete fractures were significantly increased after pre-loading. In contrast, the failure mode of the BLS group remained unchanged, showing only partial fracture even after pre-loading. This Ce-TZP/A framework design, comprised of an anatomical shape with additional buccal and lingual structures, has the potential to reduce the chipping of the veneering porcelain.

  10. Design of the MPRI Control System

    CERN Document Server

    Collins, J C; Broderick, B; Katuin, J; Manwaring, W; Schreuder, N; Manwaring, Wm.

    2001-01-01

    The Indiana University Cyclotron Facility (IUCF) is in the process of building the Midwest Proton Radiation Institute (MPRI). This involves refurbishing the 200MeV cyclotron and building new facilities for the purpose of providing clinical treatment of human cancer tumors. First patients are expected in the Spring of 2003. This paper presents the design and implementation to date of the controls, hardware and software, for both accelerator and treatment areas. Particular attention is placed on issues of personnel safety and control system security, development of inexpensive VMEbus boards with emphasis on the use of MicroChip PIC processors, beam diagnostics and monitoring and the use of commercial robots and vision systems for patient positioning.

  11. Method for designing and controlling compliant gripper

    Science.gov (United States)

    Spanu, A. R.; Besnea, D.; Avram, M.; Ciobanu, R.

    2016-08-01

    The compliant grippers are useful for high accuracy grasping of small objects with adaptive control of contact points along the active surfaces of the fingers. The spatial trajectories of the elements become a must, due to the development of MEMS. The paper presents the solution for the compliant gripper designed by the authors, so the planar and spatial movements are discussed. At the beginning of the process, the gripper could work as passive one just for the moment when it has to reach out the object surface. The forces provided by the elements have to avoid the damage. As part of the system, the camera is taken picture of the object, in order to facilitate the positioning of the system. When the contact is established, the mechanism is acting as an active gripper by using an electrical stepper motor, which has controlled movement.

  12. Clinical outcome after traumatic spinal fractures in patients with ankylosing spinal disorders compared with control patients.

    NARCIS (Netherlands)

    Westerveld, L.A.; van Bemmel, J.C.; Dhert, W.J.A.; Öner, F.C.; Verlaan, J.J.

    2014-01-01

    Background context The clinical outcome of patients with ankylosing spinal disorders (ASDs) sustaining a spinal fracture has been described to be worse compared with the general trauma population. Purpose To investigate clinical outcome (neurologic deficits, complications, and mortality) after spina

  13. Influence of preparation design and ceramic thicknesses on fracture resistance and failure modes of premolar partial coverage restorations.

    Science.gov (United States)

    Guess, Petra C; Schultheis, Stefan; Wolkewitz, Martin; Zhang, Yu; Strub, Joerg R

    2013-10-01

    Preparation designs and ceramic thicknesses are key factors for the long-term success of minimally invasive premolar partial coverage restorations. However, only limited information is presently available on this topic. The purpose of this in vitro study was to evaluate the fracture resistance and failure modes of ceramic premolar partial coverage restorations with different preparation designs and ceramic thicknesses. Caries-free human premolars (n=144) were divided into 9 groups. Palatal onlay preparation comprised reduction of the palatal cusp by 2 mm (Palatal Onlay Standard), 1 mm (Palatal-Onlay-Thin), or 0.5 mm (Palatal Onlay Ultrathin). Complete-coverage onlay preparation additionally included the buccal cusp (Occlusal Onlay Standard; Occlusal Onlay Thin; Occlusal Onlay Ultrathin). Labial surface preparations with chamfer reductions of 0.8 mm (Complete-Veneer-Standard), 0.6 mm (Complete-Veneer-Thin), and 0.4 mm (Complete Veneer Ultrathin) were implemented for complete veneer restorations. Restorations were fabricated from a pressable lithium disilicate ceramic (IPS-e.max-Press) and cemented adhesively (Syntac-Classic/Variolink-II). All specimens were subjected to cyclic mechanical loading (F=49 N, 1.2 million cycles) and simultaneous thermocycling (5°C to 55°C) in a mouth-motion simulator. After fatigue, restorations were exposed to single-load-to-failure. Two-way ANOVA was used to identify statistical differences. Pair-wise differences were calculated and P-values were adjusted by the Tukey-Kramer method (α=.05). All specimens survived fatigue. Mean (SD) load to failure values (N) were as follows: 837 (320/Palatal-Onlay-Standard), 1055 (369/Palatal-Onlay-Thin), 1192 (342/Palatal-Onlay-Ultrathin), 963 (405/Occlusal-Onlay-Standard), 1108 (340/Occlusal-Onlay-Thin), 997 (331/Occlusal-Onlay-Ultrathin), 1361 (333/Complete-Veneer-Standard), 1087 (251/Complete-Veneer-Thin), 883 (311/Complete-Veneer-Ultrathin). Palatal-onlay restorations revealed a significantly

  14. Back to the future – feasibility of recruitment and retention to patient education and telephone follow-up after hip fracture: a pilot randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Langford DP

    2015-09-01

    Full Text Available Dolores P Langford,1,2 Lena Fleig,3–5 Kristin C Brown,3,4 Nancy J Cho,1,2 Maeve Frost,1 Monique Ledoyen,1 Jayne Lehn,1 Kostas Panagiotopoulos,1,6 Nina Sharpe,1 Maureen C Ashe3,4 1Vancouver Coastal Health, 2Department of Physical Therapy, The University of British Columbia (UBC, 3Department of Family Practice, The University of British Columbia (UBC, 4Centre for Hip Health and Mobility, Vancouver, BC, Canada; 5Freie Universität Berlin, Health Psychology, Berlin, Germany; 6Department of Orthopaedics, The University of British Columbia (UBC, Vancouver, BC, Canada Objectives: Our primary aim of this pilot study was to test feasibility of the planned design, the interventions (education plus telephone coaching, and the outcome measures, and to facilitate a power calculation for a future randomized controlled trial to improve adherence to recovery goals following hip fracture.Design: This is a parallel 1:1 randomized controlled feasibility study.Setting: The study was conducted in a teaching hospital in Vancouver, BC, Canada.Participants: Participants were community-dwelling adults over 60 years of age with a recent hip fracture. They were recruited and assessed in hospital, and then randomized after hospital discharge to the intervention or control group by a web-based randomization service. Treatment allocation was concealed to the investigators, measurement team, and data entry assistants and analysts. Participants and the research physiotherapist were aware of treatment allocation.Intervention: Intervention included usual care for hip fracture plus a 1-hour in-hospital educational session using a patient-centered educational manual and four videos, and up to five postdischarge telephone calls from a physiotherapist to provide recovery coaching. The control group received usual care plus a 1-hour in-hospital educational session using the educational manual and videos.Measurement: Our primary outcome was feasibility, specifically recruitment

  15. Quantifying sedimentary and diagenetic controls on fracturing: an application in rock engineering systems

    Science.gov (United States)

    Rafiei, Mehrnoush; Rahimpour-Bonab, Hossain; Tavakoli, Vahid; Khorasani, Emad

    2016-12-01

    Several studies have been carried out to understand and justify the influences of depositional and post depositional (diagenetic) processes on the fracturing and its features. However, the effecting parameters are not completely understood yet. In this research, 1440 datasets, obtained from thin sections and cores analysis from one well in the Dalan and Kangan carbonate reservoir are considered to evaluate the effect of various depositional-diagenetic parameters on the fracturing. The considered parameters include lithology, facies, dolomitization (crystal size and shape), porosity, stylolitization and anhydrite nodules and they are further subdivided based on their fracture intensity. Then, the rock engineering systems (RES) approach is employed to weight them. Moreover, an interaction matrix is provided in which the main parameters are arranged along its main diagonal elements while the interrelations between pairs of parameters are distributed in its off-diagonal elements. The weighting coefficient of each parameter is calculated through this matrix. According to the calculations, facies and porosity are the most causal and effected parameters, respectively. The Fracture Index is obtained by using the weighting coefficient and normalized code of the parameters in the classification. Additionally, a polynomial equation with the coefficient of determination (R 2), in FI versus number of fractures (FN) diagram, is gained 0.735 where the number of fractures is enhanced with increase in FI. Finally, 300 datasets of the data are utilized to validate the methodology. The FIs of these data (predicted values) show a proper correlation with FNs (real values).

  16. Randomized controlled trials - a matter of design.

    Science.gov (United States)

    Spieth, Peter Markus; Kubasch, Anne Sophie; Penzlin, Ana Isabel; Illigens, Ben Min-Woo; Barlinn, Kristian; Siepmann, Timo

    2016-01-01

    Randomized controlled trials (RCTs) are the hallmark of evidence-based medicine and form the basis for translating research data into clinical practice. This review summarizes commonly applied designs and quality indicators of RCTs to provide guidance in interpreting and critically evaluating clinical research data. It further reflects on the principle of equipoise and its practical applicability to clinical science with an emphasis on critical care and neurological research. We performed a review of educational material, review articles, methodological studies, and published clinical trials using the databases MEDLINE, PubMed, and ClinicalTrials.gov. The most relevant recommendations regarding design, conduction, and reporting of RCTs may include the following: 1) clinically relevant end points should be defined a priori, and an unbiased analysis and report of the study results should be warranted, 2) both significant and nonsignificant results should be objectively reported and published, 3) structured study design and performance as indicated in the Consolidated Standards of Reporting Trials statement should be employed as well as registration in a public trial database, 4) potential conflicts of interest and funding sources should be disclaimed in study report or publication, and 5) in the comparison of experimental treatment with standard care, preplanned interim analyses during an ongoing RCT can aid in maintaining clinical equipoise by assessing benefit, harm, or futility, thus allowing decision on continuation or termination of the trial.

  17. Total energy control system autopilot design with constrained parameter optimization

    Science.gov (United States)

    Ly, Uy-Loi; Voth, Christopher

    1990-01-01

    A description is given of the application of a multivariable control design method (SANDY) based on constrained parameter optimization to the design of a multiloop aircraft flight control system. Specifically, the design method is applied to the direct synthesis of a multiloop AFCS inner-loop feedback control system based on total energy control system (TECS) principles. The design procedure offers a structured approach for the determination of a set of stabilizing controller design gains that meet design specifications in closed-loop stability, command tracking performance, disturbance rejection, and limits on control activities. The approach can be extended to a broader class of multiloop flight control systems. Direct tradeoffs between many real design goals are rendered systematic by proper formulation of the design objectives and constraints. Satisfactory designs are usually obtained in few iterations. Performance characteristics of the optimized TECS design have been improved, particularly in the areas of closed-loop damping and control activity in the presence of turbulence.

  18. Effect of a Home Bleaching Agent on the Fracture Toughness of Resin Composites: using short rod design

    Directory of Open Access Journals (Sweden)

    Bagheri R.

    2013-10-01

    Full Text Available Statement of Problem: Resin composites are brittle materials and their major shortcomings are manifested in their sensitivity to flaws and defects. Although various mechanical properties of resin composites have been described, few studies are available on assessing the effect of bleaching agents on resin composites using the short rod design. Materials and Method: Specimens were prepared from three resin composites; Rok (SDI, Esthet (Dentsply, and Estelite (Tokuyama. For each material, a total of 24 disc-shaped specimens were prepared using a custom-made mould. Specimens were randomly divided into 3 groups of 8 and conditioned in 37°C distilled water for either 24 hours, or 21 days. 21 day specimens were tested both with and without applying bleaching agent; Polanight (SDI. Study group specimens were bleached for 21 days, 2 hours a day. The specimens were loaded using a universal testing machine with a crosshead speed of 0.5 mm per minute. The maximum load at specimen failure was recorded and the KIc (MPa. M 0.5 was calculated. Results: Statistical analysis using two-way ANOVA showed a significant relationship between material and time (p< 0.05. Tukey’s test showed that after 24 h of immersion in distilled water, Rok revealed the highest KIc followed by Esthet and Estelite. The bleaching agent significantly improved the fracture toughness values of Esthet while it decreased that of Estelite. Conclusion: The fracture toughness of the resin composites was affected by the bleaching agent and distilled water. In comparison with Rok and Estelite, fracture toughness of Esthet was increased due to aging and application of bleaching agent.

  19. Hydrogen fracture toughness tester completion

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Michael J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-09-30

    The Hydrogen Fracture Toughness Tester (HFTT) is a mechanical testing machine designed for conducting fracture mechanics tests on materials in high-pressure hydrogen gas. The tester is needed for evaluating the effects of hydrogen on the cracking properties of tritium reservoir materials. It consists of an Instron Model 8862 Electromechanical Test Frame; an Autoclave Engineering Pressure Vessel, an Electric Potential Drop Crack Length Measurement System, associated computer control and data acquisition systems, and a high-pressure hydrogen gas manifold and handling system.

  20. Fracture stability of anterior zirconia crowns with different core designs and veneered using the layering or the press-over technique.

    Science.gov (United States)

    Eisenburger, Michael; Mache, Tobias; Borchers, Lothar; Stiesch, Meike

    2011-06-01

    In the current in vitro study, the fracture stability of anterior crowns with zirconia cores of different designs was investigated after applying different veneering techniques. Four groups of zirconia cores (n = 10 in each group) were produced using a computer-aided design/computer-aided manufacturing (CAD/CAM) process. Cores with a standard cervical design were veneered using the layering technique (CCL) or the press-over technique (CCP). Further cores were designed with a porcelain shoulder, where the cervical margin of the zirconia core was reduced by 1 mm. These cores were also veneered using the layering technique (PSL) or the press-over technique (PSP). All crowns were cemented onto metal teeth and loaded until fracture in a universal testing machine. Chipping or fracture of the core was found to occur for CCL at 919±265 N (mean ±SD), for CCP at 798±226 N, for PSL at 739±184 N, and for PSP at 734±209 N. anova did not show significant differences between the four groups. For CCL and CCP, fracture lines ran in a mesio-distal orientation. For PSL and PSP, fracture lines ran into the porcelain shoulder. In summary, the use of a porcelain shoulder can be recommended with zirconia crowns in combination with either the layering or the press-over veneering technique.

  1. On the design of chemical processes with improved controllability characteristics

    NARCIS (Netherlands)

    Meeuse, F.M.

    2003-01-01

    Traditionally, process design and control system design are carried out sequentially. The premise underlying this sequential approach is that the decisions made in the process design phase do not limit the control design. However, it is generally known that incongruent designs can occur quite

  2. On the design of chemical processes with improved controllability characteristics

    NARCIS (Netherlands)

    Meeuse, F.M.

    2003-01-01

    Traditionally, process design and control system design are carried out sequentially. The premise underlying this sequential approach is that the decisions made in the process design phase do not limit the control design. However, it is generally known that incongruent designs can occur quite easily

  3. Fracture-driven methane bubble ascent within shallow fine-grained clay-bearing aquatic sediments: dynamics and controlling factors

    Science.gov (United States)

    Tarboush Sirhan, Shahrazad; Katsman, Regina; Ten Brink, Uri

    2017-04-01

    Mature methane gas bubbles in the fine-grained, clay-bearing (cohesive) aquatic sediments, found at many locations throughout the world, are much larger than the characteristic pore size. When gas pressure within the bubble is high enough to overcome compression, friction, and cohesion at grain contacts, gas migrates upward driven by buoyancy, by pushing the grains apart and fracturing the fine-grained sediments. Fracturing of the fine-grained cohesive sediments by the migrating bubbles destabilizes sediment and might result in slope failure. Migrating methane bubbles may bypass processes of oxidation in the upper sediment layers due to their fast rise velocity, release to the water column and eventually to the atmosphere. In this study we use coupled macroscopic single-bubble mechanical/reaction-transport numerical model to explore bubble ascent under various ambient concentration profiles, associated with bio-chemical processes of methane production and consumption below sediment-water interface, as it occurs in nature. Modeling results show that changes in the ambient dissolved-methane concentrations strongly affect bubble ascent velocity. It is demonstrated that bubble migration scenario within fine-grained muddy sediments is controlled dominantly by the internal bubble pressure that manages solute exchange with adjacent porewater. It is significantly affected by the total hydrostatic pressure. For shallow water depths two sequential bubble propagation patterns were observed: (1) Stable (saw-tooth) fracturing, followed by (2) Dynamic (unstable, rising line) fracturing, leading to an ultimate release of the bubble to the water column. However, for a higher water depth, bubble propagation pattern is characterized by stable fracturing only. In this pattern the bubble becomes more sensitive to the ambient field of methane concentrations and may stop below sediment-water interface due solute release caused by the local methanotrophy.

  4. Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin

    Energy Technology Data Exchange (ETDEWEB)

    Robert Jacobi; John Fountain; Stuart Loewenstein; Edward DeRidder; Bruce Hart

    2007-03-31

    rift faults have been episodically reactivated, and a few of these faults extend through the entire stratigraphic section. The ENE-trending faults and N-striking transfer zones controlled the development of the T/BR grabens. In both the Seneca Lake and Cayuga Lake regions, we found more FIDs than Landsat lineaments, both in terms of individual FIDs and trends of FIDs. Our fused Landsat/ASTER image provided more lineaments, but the structural framework inferred from these lineaments is incomplete even for the fused image. Individual lineaments may not predict surface FIDs (within 500m). However, an individual lineament that has been groundtruthed by outcrop FIDs can be used as a proxy for the trend of intense fracturing. Aeromagnetics and seismic reflection data across the discovery fields west of Keuka Lake demonstrate that the fields terminate on the east against northerly-striking faults that extend from Precambrian basement to, in some cases, the surface; the fields terminate in the west at N- and NW-striking faults. Seismic and well log data show that the fields must be compartmentalized, since different parts of the same field show different histories of development. T/BR fields south of the research area also terminate (on the east) against northerly-trending lineaments which we suggest mark faults. Phase II, completed in 2006, consisted of collection and analysis of an oriented, horizontal core retrieved from one of the T/BR fields in a graben south of the field area. The field is located along ENE-trending EarthSat (1997) lineaments, similar to that hypothesized for the study area. The horizontal core shows much evidence for reactivation along the ENE-trending faults, with multiple events of vein development and both horizontal and vertical stylolite growth. Horizontal veins that post- and pre-date other vein sets indicate that at least two orogenic phases (separated by unloading) affected vein development. Many of the veins and releasing bend features

  5. Innovative Methodology for Detection of Fracture-Controlled Sweet Spots in the Northern Appalachian Basin

    Energy Technology Data Exchange (ETDEWEB)

    Robert Jacobi; John Fountain; Stuart Loewenstein; Edward DeRidder; Bruce Hart

    2007-03-31

    rift faults have been episodically reactivated, and a few of these faults extend through the entire stratigraphic section. The ENE-trending faults and N-striking transfer zones controlled the development of the T/BR grabens. In both the Seneca Lake and Cayuga Lake regions, we found more FIDs than Landsat lineaments, both in terms of individual FIDs and trends of FIDs. Our fused Landsat/ASTER image provided more lineaments, but the structural framework inferred from these lineaments is incomplete even for the fused image. Individual lineaments may not predict surface FIDs (within 500m). However, an individual lineament that has been groundtruthed by outcrop FIDs can be used as a proxy for the trend of intense fracturing. Aeromagnetics and seismic reflection data across the discovery fields west of Keuka Lake demonstrate that the fields terminate on the east against northerly-striking faults that extend from Precambrian basement to, in some cases, the surface; the fields terminate in the west at N- and NW-striking faults. Seismic and well log data show that the fields must be compartmentalized, since different parts of the same field show different histories of development. T/BR fields south of the research area also terminate (on the east) against northerly-trending lineaments which we suggest mark faults. Phase II, completed in 2006, consisted of collection and analysis of an oriented, horizontal core retrieved from one of the T/BR fields in a graben south of the field area. The field is located along ENE-trending EarthSat (1997) lineaments, similar to that hypothesized for the study area. The horizontal core shows much evidence for reactivation along the ENE-trending faults, with multiple events of vein development and both horizontal and vertical stylolite growth. Horizontal veins that post- and pre-date other vein sets indicate that at least two orogenic phases (separated by unloading) affected vein development. Many of the veins and releasing bend features

  6. Glycemic Control with Thiazolidinedione Is Associated with Fracture of T2DM Patients.

    Directory of Open Access Journals (Sweden)

    Hsin-Hung Chen

    Full Text Available Diabetes is a common diseases and a major problem worldwide. Diabetic osteopathy might be elevated in diabetic patients and is usually caused by bone fracture. Several diabetes medications, such as thiazolidinediones (TZDs, could lead to increased risks of fracture.We used the nationwide database to identified 32466 patients who had developed type 2 diabetes from 2000 to 2010 as the diabetic cohort and, from that group, we selected 3427 diabetic patients who had developed bone fracture to survey the possible risk factors, includng commonly used diabetes medication.We found that TZDs might present increased risks for fracture in patients who used it for an extended period (7 to 730 days before the index date, especially in female patients younger than 64 years old, for whom the risk was elevated from a 1.74- to a 2.58-fold odds ratio.We recommend that clinics follow up with non-osteoporotic female patients younger than 64 years old who are using TZDs, to avoid the associated risks of fracture.

  7. Subduction of fracture zones controls mantle melting and geochemical signature above slabs.

    Science.gov (United States)

    Manea, Vlad C; Leeman, William P; Gerya, Taras; Manea, Marina; Zhu, Guizhi

    2014-10-24

    For some volcanic arcs, the geochemistry of volcanic rocks erupting above subducted oceanic fracture zones is consistent with higher than normal fluid inputs to arc magma sources. Here we use enrichment of boron (B/Zr) in volcanic arc lavas as a proxy to evaluate relative along-strike inputs of slab-derived fluids in the Aleutian, Andean, Cascades and Trans-Mexican arcs. Significant B/Zr spikes coincide with subduction of prominent fracture zones in the relatively cool Aleutian and Andean subduction zones where fracture zone subduction locally enhances fluid introduction beneath volcanic arcs. Geodynamic models of subduction have not previously considered how fracture zones may influence the melt and fluid distribution above slabs. Using high-resolution three-dimensional coupled petrological-thermomechanical numerical simulations of subduction, we show that enhanced production of slab-derived fluids and mantle wedge melts concentrate in areas where fracture zones are subducted, resulting in significant along-arc variability in magma source compositions and processes.

  8. Introduction to multicopter design and control

    CERN Document Server

    Quan, Quan

    2017-01-01

    This book is the first textbook specially on multicopter systems in the world. It provides a comprehensive overview of multicopter systems, rather than focusing on a single method or technique. The fifteen chapters are divided into five parts, covering the topics of multicopter design, modeling, state estimation, control, and decision-making. It differs from other books in the field in three major respects: it is basic and practical, offering self-contained content and presenting hands-on methods; it is comprehensive and systematic; and it is timely. It is also closely related to the autopilot that users often employ today and provides insights into the code employed. As such, it offers a valuable resource for anyone interested in multicopters, including students, teachers, researchers, and engineers.

  9. Fractures in multiple sclerosis

    DEFF Research Database (Denmark)

    Stenager, E; Jensen, K

    1991-01-01

    In a cross-sectional study of 299 MS patients 22 have had fractures and of these 17 after onset of MS. The fractures most frequently involved the femoral neck and trochanter (41%). Three patients had had more than one fracture. Only 1 patient had osteoporosis. The percentage of fractures increased...... with increasing age and disease duration. Among 34 deceased MS patients 4 had had fractures. These findings are discussed in relation to physical and cognitive impairment in MS. A case-control study is recommended....

  10. Low bone mineral density is a significant risk factor for low-energy distal radius fractures in middle-aged and elderly men: A case-control study

    Directory of Open Access Journals (Sweden)

    Johnsen Villy

    2011-04-01

    Full Text Available Abstract Background In general there is a lack of data on osteoporosis and fracture in men; this also includes low-energy distal radius fractures. The objectives of this study were to examine BMD and identify factors associated with distal radius fractures in male patients compared with controls recruited from the background population. Methods In a 2-year period, 44 men 50 years or older were diagnosed with low-energy distal radius fractures, all recruited from one hospital. The 31 men who attended for osteoporosis assessment were age-matched with 35 controls. Demographic and clinical data were collected and BMD at femoral neck, total hip and spine L2-4 was assessed by dual energy X-ray absorptiometry. Results Apart from weight and living alone, no significant differences were found between patient and controls for demographic variables (e.g. height, smoking and clinical variables (e.g. co-morbidity, use of glucocorticoids, osteoporosis treatment, falls and previous history of fracture. However, BMD expressed as T-score was significant lower in patients than in controls at all measurement sites (femoral neck: -2.24 vs. -1.15, p Conclusion The results from our study indicate that reduced BMD is an important risk factor for low-energy distal radius fracture in men. This suggests that improvement of BMD by both pharmacological and non-pharmacological initiatives may be a strategy to reduce fracture risk in men.

  11. Are L5 fractures an indicator of metastasis?

    Energy Technology Data Exchange (ETDEWEB)

    Lo, L.D.; Schweitzer, M.E.; Juneja, V.; Shabshin, N. [Thomas Jefferson Univ., Philadelphia, PA (United States). Dept. of Radiology

    2000-08-01

    Objective. To determine whether L5 vertebral body fractures are an indicator of malignancy.Design and patients. A retrospective study of L5 vertebral body fractures was carried out using plain radiographs, CT, and/or MRI. Over a 5-year period, 51 patients with L5 vertebral body fractures were seen at our institution. Since L1 vertebral body fractures are common, 51 age- and gender-matched (20 men, 31 women; mean age 60 years) patients with L1 fractures were utilized as the control group. The frequency of neoplastic infiltration of the vertebrae was compared between these two populations to determine whether pathologic fracture was more frequent at L5.Results. Twelve (24%) of the L5 fractures were pathologic compared with four (8%) of the L1 fractures (chi-square test, P<0.05). Neoplasm types included multiple myeloma (n=4), prostate (n=3), breast (n=2), lung (n=2), melanoma (n=2), bladder, colon, and leukemia (each n=1).Conclusion. Although most L5 fractures are not pathologic, there is an increased incidence of pathologic fractures in this location compared with L1. Therefore, a fracture of L5 should raise the suspicion of metastasis. (orig.)

  12. Scheduled Controller Design of Congestion Control Considering Network Resource Constraints

    Science.gov (United States)

    Naito, Hiroyuki; Azuma, Takehito; Fujita, Masayuki

    In this paper, we consider a dynamical model of computer networks and derive a synthesis method for congestion control. First, we show a model of TCP/AQM (Transmission Control Protocol/Active Queue Management) as a dynamical model of computer networks. The dynamical model of TCP/AQM networks consists of models of TCP window size, queue length and AQM mechanisms. Second, we propose to describe the dynamical model of TCP/AQM networks as linear systems with self-scheduling parameters, which also depend on information delay. Here we focus on the constraints on the maximum queue length and TCP window-size, which are the network resources in TCP/AQM networks. We derive TCP/AQM networks as the LPV system (linear parameter varying system) with information delay and self-scheduling parameter. We design a memoryless state feedback controller of the LPV system based on a gain-scheduling method. Finally, the effectiveness of the proposed method is evaluated by using MATLAB and the well-known ns-2 (Network Simulator Ver.2) simulator.

  13. The middle layer of lumbar fascia and attachments to lumbar transverse processes: implications for segmental control and fracture

    Science.gov (United States)

    Urquhart, Donna M.; Story, Ian H.; Fahrer, Marius; Briggs, Christopher A.

    2007-01-01

    The anatomy of the middle layer of lumbar fascia (MLF) is of biomechanical interest and potential clinical relevance, yet it has been inconsistently described. Avulsion fractures of the lumbar transverse processes (LxTP’s) are traditionally attributed to traction from psoas major or quadratus lumborum (QL), rather than transversus abdominis (TrA) acting via the MLF. This attachment is also absent from many biomechanical models of segmental control. The aims of this study were to document: (1) the morphology and attachments of the MLF and (2) the attachments of psoas and QL to the LxTP’s. Eighteen embalmed cadavers were dissected, measuring the thickness, fibre angle and width of the MLF and documenting the attachments of MLF, psoas and QL. The MLF was thicker at the level of the LxTP’s than between them (mean 0.62: 0.40 mm). Psoas attached to the anteromedial surface of each process and QL and TrA to its lateral border; QL at its upper and lower corners and TrA (via the MLF) to its tip. In three cadavers, tension applied to the MLF fractured a transverse process. The MLF has a substantial and thickened attachment to the tips of the LxTP’s which supports the involvement of TrA in lumbar segmental control and/ or avulsion fracture of the LxTP’s. PMID:17924150

  14. Analysis and design of networked control systems

    CERN Document Server

    You, Keyou; Xie, Lihua

    2015-01-01

    This monograph focuses on characterizing the stability and performance consequences of inserting limited-capacity communication networks within a control loop. The text shows how integration of the ideas of control and estimation with those of communication and information theory can be used to provide important insights concerning several fundamental problems such as: ·         minimum data rate for stabilization of linear systems over noisy channels; ·         minimum network requirement for stabilization of linear systems over fading channels; and ·         stability of Kalman filtering with intermittent observations. A fundamental link is revealed between the topological entropy of linear dynamical systems and the capacities of communication channels. The design of a logarithmic quantizer for the stabilization of linear systems under various network environments is also extensively discussed and solutions to many problems of Kalman filtering with intermittent observations are de...

  15. The design of traffic signal coordinated control

    Science.gov (United States)

    Guo, Xueting; Sun, Hongsheng; Wang, Xifu

    2017-05-01

    Traffic as the tertiary industry is an important pillar industry to support the normal development of the economy. But now China's road traffic development and economic development has shown a great imbalance and fault phenomenon, which greatly inhibited the normal development of China's economy. Now in many large and medium-sized cities in China are implementing green belt construction. The so-called green band is when the road conditions to meet the conditions for the establishment of the green band, the sections of the intersection of several planning to a traffic coordination control system, so that when the driver at a specific speed can be achieved without stopping the continuous Through the intersection. Green belt can effectively reduce the delay and queuing length of vehicle driving, the normal function of urban roads and reduce the economic losses caused by traffic congestion is a great help. In this paper, the theoretical basis of the design of the coordinated control system is described. Secondly, the green time offset is calculated by the analytic method and the green band is established. And then the VISSIM software is used to simulate the traffic system before and after the improvement. Finally, the results of the two simulations are compared.

  16. Feedback Control Systems Loop Shaping Design with Practical Considerations

    Science.gov (United States)

    Kopsakis, George

    2007-01-01

    This paper describes loop shaping control design in feedback control systems, primarily from a practical stand point that considers design specifications. Classical feedback control design theory, for linear systems where the plant transfer function is known, has been around for a long time. But it s still a challenge of how to translate the theory into practical and methodical design techniques that simultaneously satisfy a variety of performance requirements such as transient response, stability, and disturbance attenuation while taking into account the capabilities of the plant and its actuation system. This paper briefly addresses some relevant theory, first in layman s terms, so that it becomes easily understood and then it embarks into a practical and systematic design approach incorporating loop shaping design coupled with lead-lag control compensation design. The emphasis is in generating simple but rather powerful design techniques that will allow even designers with a layman s knowledge in controls to develop effective feedback control designs.

  17. Tai Chi for osteopenic women: design and rationale of a pragmatic randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Fischer Mary

    2010-03-01

    Full Text Available Abstract Background Post-menopausal osteopenic women are at increased risk for skeletal fractures. Current osteopenia treatment guidelines include exercise, however, optimal exercise regimens for attenuating bone mineral density (BMD loss, or for addressing other fracture-related risk factors (e.g. poor balance, decreased muscle strength are not well-defined. Tai Chi is an increasingly popular weight bearing mind-body exercise that has been reported to positively impact BMD dynamics and improve postural control, however, current evidence is inconclusive. This study will determine the effectiveness of Tai Chi in reducing rates of bone turnover in post-menopausal osteopenic women, compared with standard care, and will preliminarily explore biomechanical processes that might inform how Tai Chi impacts BMD and associated fracture risks. Methods/Design A total of 86 post-menopausal women, aged 45-70y, T-score of the hip and/or spine -1.0 and -2.5, have been recruited from primary care clinics of a large healthcare system based in Boston. They have been randomized to a group-based 9-month Tai Chi program plus standard care or to standard care only. A unique aspect of this trial is its pragmatic design, which allows participants randomized to Tai Chi to choose from a pre-screened list of community-based Tai Chi programs. Interviewers masked to participants' treatment group assess outcomes at baseline and 3 and 9 months after randomization. Primary outcomes are serum markers of bone resorption (C-terminal cross linking telopeptide of type I collagen, bone formation (osteocalcin, and BMD of the lumbar spine and proximal femur (dual-energy X-ray absorptiometry. Secondary outcomes include health-related quality-of-life, exercise behavior, and psychological well-being. In addition, kinetic and kinematic characterization of gait, standing, and rising from a chair are assessed in subset of participants (n = 16 to explore the feasibility of modeling skeletal

  18. Hypnotics and the Occurrence of Bone Fractures in Hospitalized Dementia Patients: A Matched Case-Control Study Using a National Inpatient Database.

    Directory of Open Access Journals (Sweden)

    Hiroyuki Tamiya

    Full Text Available Preventing falls and bone fractures in hospital care is an important issue in geriatric medicine. Use of hypnotics is a potential risk factor for falls and bone fractures in older patients. However, data are lacking on the association between use of hypnotics and the occurrence of bone fracture.We used a national inpatient database including 1,057 hospitals in Japan and included dementia patients aged 50 years or older who were hospitalized during a period of 12 months between April 2012 and March 2013. The primary outcome was the occurrence of bone fracture during hospitalization. Use of hypnotics was compared between patients with and without bone fracture in this matched case-control study.Of 140,494 patients, 830 patients suffered from in-hospital fracture. A 1:4 matching with age, sex and hospital created 817 cases with fracture and 3,158 matched patients without fracture. With adjustment for the Charlson comorbidity index, emergent admission, activities of daily living, and scores for level walking, a higher occurrence of fractures were seen with short-acting benzodiazepine hypnotics (odds ratio, 1.43; 95% confidence interval, 1.19-1.73; P<0.001, ultrashort-acting non-benzodiazepine hypnotics (1.66; 1.37-2.01; P<0.001, hydroxyzine (1.45; 1.15-1.82, P=0.001, risperidone and perospirone (1.37; 1.08-1.73; P=0.010. Other drug groups were not significantly associated with the occurrence of in-hospital fracture.Short-acting benzodiazepine hypnotics and ultrashort-acting non-benzodiazepine hypnotics may increase risk of bone fracture in hospitalized dementia patients.

  19. Dynamic aerofracture or hydrofracture of dense granular packing: pressure and viscosity control of the fracture patterns

    Science.gov (United States)

    Niebling, Michael J.; Toussaint, Renaud; Flekkøy, Eirik G.; Jørgen Måløy, Knut

    2013-04-01

    Stress induced by fluid or gases can cause diverse materials to break and fracture. Such hydraulic fractures are a natural and common phenomenon in the field of volcanism and are artificially initiated to enhance the recovery of natural gas and mineral oil by fracturing the reservoir rock with pressurized fluids. A procedure also known as fracking. Recently a new perspective on hydrofractures was added with the storage of supercritical CO2. In this respect two scenarios are considered. First it is one option to inject CO2 into existing hydrofractures, and second the injection of the CO2 can create additional fractures. The typical components for such fractures are a porous material and a compressible gas. The dynamics of such fractures and displacement patterns are simulated and studied in a rectangular Hele-Shaw cell filled with a dense but permeable two-dimensional granular layer. The model used, mixing highly deformable solid and fluid components, can simulate sedimentation problems [1,2], as well as hydrofracture or aerofracture ones. The emerging displacement patterns and fractures variate according to the properties of the injected fluid or gas and the characteristics of the granular phase [3]. The physics behind these variations is discussed and explained. The role of the fluid viscosity and system size shows to lead to a transition from fracturing to compaction, depending on the dynamics of convection versus diffusion of overpressure. The dependence of the obtained patterns on the injection pressure is also explored [4]. References: [1] Niebling, M.J., E.G. Flekkøy, K.J. Måløy, R. Toussaint, Sedimentation instabilities: impact of the fluid compressibility and viscosity, Phys. Rev. E 82, 051302, 2010. doi: 10.1103/PhysRevE.82.051302 [2] Niebling, M.J., E.G. Flekkøy, K.J. Måløy, R. Toussaint, Mixing of a granular layer falling through a fluid, Phys. Rev. E 82, 011301 (2010) doi: 10.1103/PhysRevE.82.011301 [3] Niebling, M., R. Toussaint, E.G. Flekk

  20. A New Approach to Design of Dependable Control Systems

    DEFF Research Database (Denmark)

    Blanke, M.; Jørgensen, R.B.; Svavarsson, M.

    1996-01-01

    This paper presents a new method for design of fault handling as a supervisory part of a control system.......This paper presents a new method for design of fault handling as a supervisory part of a control system....

  1. A New Approach to Design of Dependable Control Systems

    DEFF Research Database (Denmark)

    Blanke, M.; Jørgensen, R.B.; Svavarsson, M.

    1995-01-01

    This paper presents a new method for design of fault handling as a supervisory part of a control system.......This paper presents a new method for design of fault handling as a supervisory part of a control system....

  2. Design package for programmable controller and hydronic subsystem

    Science.gov (United States)

    1979-01-01

    Information used in the evaluation of design of Sunkeeper Control's electronic controllers and hydronic packages is discussed. This information includes system performance specifications, a design data brochure, drawings, and qualification and acceptance test procedures.

  3. Is groundwater age the main control for slow turnover of nitrate in a fractured groundwater system?

    Science.gov (United States)

    Osenbrück, Karsten; Schwientek, Marc; Rügner, Hermann; Grathwohl, Peter

    2015-04-01

    Slow transformation processes are known to control the chemical, isotopic, and redox evolution of large-scale aquifers (Edmunds et al., 1982; Katz et al., 1995). However, at the field scale some of the crucial biogeochemical processes governing pollutant turnover and their interrelations with hydrology are poorly understood. Particularly, only little is known about denitrification in fractured rock aquifers. Therefore, the main objective of the presented study is to assess where and how slow turnover of nitrate ans other pollutants in the deeper subsurface take place. The studied fractured and partly karstified aquifer consisting of Triassic black limestones and dolomites is located in the catchment of the Ammer river (ca. 350 km²) close to Tübingen in southern Germany. Near the recharge area, the aquifer is covered by loess allowing intensive agriculture. Further downgradient, the cover consist of a series of mudstones and sandstones of variable permeability. The aquifer is used for drinking water purposes by regional water suppliers. Land-use is dominated by agriculture with arable land covering nearly 50% of the catchment. Over the last years a variety of groundwater samples have been collected from the groundwater system including 6 water supply wells, 4 karstic springs, and 9 monitoring wells in the recharge area. This allowed to identify spatial and temporal patterns of water quality including concentrations of major ions, dissolved organic carbon (DOC), organic pollutants (e.g., pesticides), and environmental isotopes. Groundwater age distributions at most of these locations were derived from tritium, 3He, CFCs and SF6. Groundwaters in the recharge area show high concentrations of nutrients (e.g. 20-51 mg/L of nitrate and 0.2 to 0.05 µg/L of phosphate). Of special concern are disparate nitrate concentrations ranging from below 0.4 to 20 mg/L in water supply wells although screen depths of the production wells are similar. Concentrations of dissolved

  4. West Valley transfer cart control system design description

    Energy Technology Data Exchange (ETDEWEB)

    Bradley, E.C.; Crutcher, R.I.; Halliwell, J.W.; Hileman, M.S.; Moore, M.R.; Nodine, R.N.; Ruppel, F.R.; Vandermolen, R.I.

    1993-01-01

    Detail design of the control system for the West Valley Nuclear Services Vitrification Facility transfer cart has been completed by Oak Ridge National Laboratory. This report documents the requirements and describes the detail design of that equipment and control software. Copies of significant design documents including analysis and testing reports and design drawings are included in the Appendixes.

  5. Secondary hyperparathyroidism and mortality in hip fracture patients compared to a control group from general practice

    DEFF Research Database (Denmark)

    Madsen, Christian Medom; Jørgensen, Henrik Løvendahl; Lind, Bent

    2012-01-01

    INTRODUCTION: Previously, little attention has been paid as to how disturbances in the parathyroid hormone (PTH)-calcium-vitamin D-axis, such as secondary hyperparathyroidism (SHPT), relate to mortality amongst hip fracture patients. This study aimed to (1) determine if SHPT is associated...

  6. The effect of C1-esterase inhibitor on systemic inflammation in trauma patients with a femur fracture - The CAESAR study: study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Strengers Paul FW

    2011-10-01

    Full Text Available Abstract Background Systemic inflammation in response to a femur fracture and the additional fixation is associated with inflammatory complications, such as acute respiratory distress syndrome and multiple organ dysfunction syndrome. The injury itself, but also the additional procedure of femoral fixation induces a release of pro-inflammatory cytokines such as interleukin-6. This results in an aggravation of the initial systemic inflammatory response, and can cause an increased risk for the development of inflammatory complications. Recent studies have shown that administration of the serum protein C1-esterase inhibitor can significantly reduce the release of circulating pro-inflammatory cytokines in response to acute systemic inflammation. Objective Attenuation of the surgery-induced additional systemic inflammatory response by perioperative treatment with C1-esterase inhibitor of trauma patients with a femur fracture. Methods The study is designed as a double-blind randomized placebo-controlled trial. Trauma patients with a femur fracture, Injury Severity Score ≥ 18 and age 18-80 years are included after obtaining informed consent. They are randomized for administration of 200 U/kg C1-esterase inhibitor intravenously or placebo (saline 0.9% just before the start of the procedure of femoral fixation. The primary endpoint of the study is Δ interleukin-6, measured at t = 0, just before start of the femur fixation surgery and administration of C1-esterase inhibitor, and t = 6, 6 hours after administration of C1-esterase inhibitor and the femur fixation. Conclusion This study intents to identify C1-esterase inhibitor as a safe and potent anti-inflammatory agent, that is capable of suppressing systemic inflammation in trauma patients. This might facilitate early total care procedures by lowering the risk of inflammation in response to the surgical intervention. This could result in increased functional outcomes and reduced health care related

  7. Carbonate fracture stratigraphy: An integrated outcrop and 2D discrete element modelling study

    Science.gov (United States)

    Spence, Guy; Finch, Emma

    2013-04-01

    Constraining fracture stratigraphy is important as natural fractures control primary fluid flow in low matrix permeability naturally fractured carbonate hydrocarbon reservoirs. Away from the influence of folds and faults, stratigraphic controls are known to be the major control on fracture networks. The fracture stratigraphy of carbonate nodular-chert rhythmite successions are investigated using a Discrete Element Modelling (DEM) technique and validated against observations from outcrops. Comparisons are made to the naturally fractured carbonates of the Eocene Thebes Formation exposed in the west central Sinai of Egypt, which form reservoir rocks in the nearby East Ras Budran Field. DEM allows mechanical stratigraphy to be defined as the starting conditions from which forward numerical modelling can generate fracture stratigraphy. DEM can incorporate both stratigraphic and lateral heterogeneity, and enable mechanical and fracture stratigraphy to be characterised separately. Stratally bound stratified chert nodules below bedding surfaces generate closely spaced lateral heterogeneity in physical properties at stratigraphic mechanical interfaces. This generates extra complexity in natural fracture networks in addition to that caused by bed thickness and lithological physical properties. A series of representative geologically appropriate synthetic mechanical stratigraphic models were tested. Fracture networks generated in 15 DEM experiments designed to isolate and constrain the effects of nodular chert rhythmites on carbonate fracture stratigraphy are presented. The discrete element media used to model the elastic strengths of rocks contain 72,866 individual elements. Mechanical stratigraphies and the fracture networks generated are placed in a sequence stratigraphic framework. Nodular chert rhythmite successions are shown to be a distinct type of naturally fractured carbonate reservoir. Qualitative stratigraphic rules for predicting the distribution, lengths, spacing

  8. Internal fixation vs conservative treatment for displaced distal radius fractures: a meta-analysis of randomized controlled trials.

    Science.gov (United States)

    Yu, Guang Shu; Lin, Yan Bin; Le, Li Sheng; Zhan, Mei Feng; Jiang, Xiao Xiang

    2016-05-01

    The aim of the present study was to compare clinical outcomes of internal fixation and conservative approach in the treatment of displaced distal radius fractures. Reports of studies were retrieved from the PubMed, Cochrane Library, EMBASE, BIOSIS, Ovid, CNKI, and Wanfang Data databases, as well as other sources. Methodological quality of the trials was critically assessed, and relevant data were extracted. Review Manager (RevMan) meta-analysis software (version 5.0; Cochrane Collaboration, London, UK) was used for data analysis. A total of 10 randomized controlled trials, which included 653 patients, were eligible for inclusion in the present meta-analysis, 7 of which were in English, and 3 of which were in Chinese. The trials had medium risk of bias. Results of meta-analysis showed that patients undergoing conservative treatment for distal radius fractures had better restoration of pronation (MD=1.80, 95% confidence interval [CI]=0.18-3.42, p=0.03; heterogeneity p=0.17, I2=43%), but shorter restoration of radial length (MD=2.62, 95% CI=1.47-3.76, pinternal fixation and conservative treatment for displaced distal radius fractures. Best course of of treatment must be determined based on concrete conditions.

  9. Electromagnetic Compatibility Design for Powertrain Control Module

    Institute of Scientific and Technical Information of China (English)

    WANG Yu-ming; CUI Tao; LIU Bo-lan; ZHANG Fu-jun

    2009-01-01

    In order to improve the electromaagnetic compatibility of powertrain control module (PCM),a system procedure of vehicular PCM electromagnetic alteration is presented in this paper.First of all,the box of the PCM is divided into different cabins to eliminate interferences between power supply circuit,analog circuit and digital circuit.Secondly,the working principle and electromagnetic (EM) characters of all the signals adopted by a typical PCM are analyzed.Then according to specific electromagnetic characters,different measures are adopted in corresponding signal process circuits or signal transfer cables,such as ground layout designing,power supply protecting,signal shielding and drive cable interference suppressing.Finally,further improvement may also needed regarding to practical electromagnetic compatibility test effects.The final test shows that,with all the measures mentioned above,the conducted emission of a PCM can be reduced by 20 dB;meanwhile,the radiated emission can be reduced by 30 dB comparing to the original system.

  10. System design and control integration for advanced manufacturing

    CERN Document Server

    Li, Han-Xiong

    2014-01-01

    Most existing robust design books address design for static systems, or achieve robust design from experimental data via the Taguchi method. Little work considers model information for robust design particularly for the dynamic system. This book covers robust design for both static and dynamic systems using the nominal model information or the hybrid model/data information, and also integrates design with control under a large operating region. This design can handle strong nonlinearity and more uncertainties from model and parameters.

  11. Transport efficiency and dynamics of hydraulic fracture networks

    Science.gov (United States)

    Sachau, Till; Bons, Paul; Gomez-Rivas, Enrique

    2015-08-01

    Intermittent fluid pulses in the Earth's crust can explain a variety of geological phenomena, for instance the occurrence of hydraulic breccia. Fluid transport in the crust is usually modeled as continuous darcian flow, ignoring that sufficient fluid overpressure can cause hydraulic fractures as fluid pathways with very dynamic behavior. Resulting hydraulic fracture networks are largely self-organized: opening and healing of hydraulic fractures depends on local fluid pressure, which is, in turn, largely controlled by the fracture network. We develop a crustal-scale 2D computer model designed to simulate this process. To focus on the dynamics of the process we chose a setup as simple as possible. Control factors are constant overpressure at a basal fluid source and a constant 'viscous' parameter controlling fracture-healing. Our results indicate that at large healing rates hydraulic fractures are mobile, transporting fluid in intermittent pulses to the surface and displaying a 1/fα behavior. Low healing rates result in stable networks and constant flow. The efficiency of the fluid transport is independent from the closure dynamics of veins or fractures. More important than preexisting fracture networks is the distribution of fluid pressure. A key requirement for dynamic fracture networks is the presence of a fluid pressure gradient.

  12. Transport efficiency and dynamics of hydraulic fracture networks

    Directory of Open Access Journals (Sweden)

    Till eSachau

    2015-08-01

    Full Text Available Intermittent fluid pulses in the Earth's crust can explain a variety of geological phenomena, for instance the occurrence of hydraulic breccia. Fluid transport in the crust is usually modeled as continuous darcian flow, ignoring that sufficient fluid overpressure can cause hydraulic fractures as fluid pathways with very dynamic behavior. Resulting hydraulic fracture networks are largely self-organized: opening and healing of hydraulic fractures depends on local fluid pressure, which is, in turn, largely controlled by the fracture network. We develop a crustal-scale 2D computer model designed to simulate this process. To focus on the dynamics of the process we chose a setup as simple as possible. Control factors are constant overpressure at a basal fluid source and a constant 'viscous' parameter controlling fracture-healing. Our results indicate that at large healing rates hydraulic fractures are mobile, transporting fluid in intermittent pulses to the surface and displaying a 1/fα behavior. Low healing rates result in stable networks and constant flow. The efficiency of the fluid transport is independent from the closure dynamics of veins or fractures. More important than preexisting fracture networks is the distribution of fluid pressure. A key requirement for dynamic fracture networks is the presence of a fluid pressure gradient.

  13. Retraction: 'Alendronate and vitamin D2 for prevention of hip fracture in Parkinson's disease: A randomized controlled trial,' by Sato, Y., Iwamoto, J., Kanoko, T., and Satoh, K.

    Science.gov (United States)

    2016-07-01

    The above article, published online on 14 March 2006 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 21, Issue 7, Pages 924-929, has been retracted by agreement between the authors, the Editor-in-Chief, Jose A. Obeso, and Wiley Periodicals, Inc. The retraction has been agreed due to an acknowledgement from the authors that the co-authors did not participate in study design, data collection, data analysis, interpretation of data and drafting the manuscript. Thus all co-authors are honorary. Reference Sato, Y., Iwamoto, J., Kanoko, T., and Satoh, K. (2006) Alendronate and vitamin D2 for prevention of hip fracture in Parkinson's disease: A randomized controlled trial. Mov Disord. doi: 10.1002/mds.20825.

  14. Hip Fracture

    Science.gov (United States)

    Diseases and Conditions Hip fracture By Mayo Clinic Staff A hip fracture is a serious injury, with complications that can be life-threatening. The risk of hip fracture rises with age. Older people are at a ...

  15. Design of saturated controllers for linear singular systems

    Institute of Scientific and Technical Information of China (English)

    Wang Ruliang; Liu Yongqing

    2005-01-01

    A designing method is presented to find stabilizing saturated linear controllers for linear continuous time and discrete time singular systems with control constraints. The idea is as follows: The system is first stabilized by a low-gain linear state feedback control. A general Lyapunov function is found, on the basis of which another linear state feedback control is computed.The second step is very similar to a relay control design. The two controls are added and saturated.

  16. Mechanical Engineering Design Project report: Enabler control systems

    Science.gov (United States)

    Cullen, Christian; Delvecchio, Dave; Scarborough, Alan; Havics, Andrew A.

    1992-01-01

    The Controls Group was assigned the responsibility for designing the Enabler's control system. The requirement for the design was that the control system must provide a simple user interface to control the boom articulation joints, chassis articulation joints, and the wheel drive. The system required controlling hydraulic motors on the Enabler by implementing 8-bit microprocessor boards. In addition, feedback to evaluate positions and velocities must be interfaced to provide the operator with confirmation as well as control.

  17. Autonomous underwater vehicles modeling, control design and simulation

    CERN Document Server

    Wadoo, Sabiha

    2010-01-01

    Underwater vehicles present some difficult and very particular control system design problems. These are often the result of nonlinear dynamics and uncertain models, as well as the presence of sometimes unforeseeable environmental disturbances that are difficult to measure or estimate. Autonomous Underwater Vehicles: Modeling, Control Design, and Simulation outlines a novel approach to help readers develop models to simulate feedback controllers for motion planning and design. The book combines useful information on both kinematic and dynamic nonlinear feedback control models, providing simula

  18. Minimally invasive percutaneous compression plating versus dynamic hip screw for intertrochanteric fractures: a randomized control trial

    Institute of Scientific and Technical Information of China (English)

    Cheng Qiang; Huang Wei; Gong Xuan; Wang Changdong; Liang Xi; Hu Ning

    2014-01-01

    Objective:Intertrochanteric femur fracture is a common injury in elderly patients.The dynamic hip screw (DHS) has served as the standard choice for fixation; however it has several drawbacks.Studies of the percutaneous compression plate (PCCP) are still inconclusive in regards to its efficacy and safety.By comparing the two methods,we assessed their clinical therapeutic outcome.Methods:Atotal of 121 elderly patients with intertrochanteric femur fractures (type AO/OTA 31.A 1-A2,Evans type 1) were divided randomly into two groups undergoing either a minimally invasive PCCP procedure or a conventional DHS fixation.Results:The mean operation duration was significantly shorter in the PCCP group (55.2 min versus 88.5 min,P<0.01).The blood loss was 156.5 ml±18.3 ml in the PCCP group and 513.2 ml±66.2 ml in the DHS group (P<0.01).Among the patients treated with PCCP,3.1% needed blood transfusions,compared with 44.6% of those that had DHS surgery (P<0.01).The PCCP group displayed less postoperative complications (P<0.05).The mean American Society of Anesthesiologists score and Harris hip score in the PCCP group were better than those in the DHS group.There were no significant differences in the mean hospital stay,mortality rates,or fracture healing.Conclusion:Due to several advantages,PCCP has the potential to become the ideal choice for treating intertrochanteric fractures (type AO/OTA 31.A1-A2,Evans type 1),particularly in the elderly.

  19. Quantifying Fracture Heterogeneity in Different Domains of Folded Carbonate Rocks to Improve Fractured Reservoir Analog Fluid Flow Models

    NARCIS (Netherlands)

    Bisdom, K.; Bertotti, G.; Gauthier, B.D.M.; Hardebol, N.J.

    2013-01-01

    Fluid flow in carbonate reservoirs is largely controlled by multiscale fracture networks. Significant variations of fracture network porosity and permeability are caused by the 3D heterogeneity of the fracture network characteristics, such as intensity, orientation and size. Characterizing fracture

  20. Embedded Control System Design A Model Based Approach

    CERN Document Server

    Forrai, Alexandru

    2013-01-01

    Control system design is a challenging task for practicing engineers. It requires knowledge of different engineering fields, a good understanding of technical specifications and good communication skills. The current book introduces the reader into practical control system design, bridging  the gap between theory and practice.  The control design techniques presented in the book are all model based., considering the needs and possibilities of practicing engineers. Classical control design techniques are reviewed and methods are presented how to verify the robustness of the design. It is how the designed control algorithm can be implemented in real-time and tested, fulfilling different safety requirements. Good design practices and the systematic software development process are emphasized in the book according to the generic standard IEC61508. The book is mainly addressed to practicing control and embedded software engineers - working in research and development – as well as graduate students who are face...

  1. Use of self-controlled designs in pharmacoepidemiology

    DEFF Research Database (Denmark)

    Hallas, J.; Pottegård, Anton

    2014-01-01

    Self-controlled observational study designs, such as the case-crossover design and the self-controlled case series, are reviewed, and their respective rationale, strengths and limitations are compared. Although no single design is generally superior to the others, they share the trait of being...... robust towards confounders that are stable over time. The self-controlled designs can be particularly useful when using secondary healthcare data for pharmacoepidemiological research and might be useful in screening for adverse drug effects. The main limitations of self-controlled designs...

  2. Optimal Tracking Controller Design for a Small Scale Helicopter

    Institute of Scientific and Technical Information of China (English)

    Agus Budiyono; Singgih S. Wibowo

    2007-01-01

    A model helicopter is more difficult to control than its full scale counterpart. This is due to its greater sensitivity to control inputs and disturbances as well as higher bandwidth of dynamics. This work is focused on designing practical tracking controller for a small scale helicopter following predefined trajectories. A tracking controller based on optimal control theory is synthesized as a part of the development of an autonomous helicopter. Some issues with regards to control constraints are addressed.The weighting between state tracking performance and control power expenditure is analyzed. Overall performance of the control design is evaluated based on its time domain histories of trajectories as well as control inputs.

  3. Feedback control design for discrete-time piecewise affine systems

    Institute of Scientific and Technical Information of China (English)

    XU Jun; XIE Li-hua

    2007-01-01

    This paper investigates the design of state feedback and dynamic output feedback stabilizing controllers for discrete-time piecewise affine (PWA) systems. The main objective is to derive design methods that will incorporate the partition information of the PWA systems so as to reduce the design conservatism embedded in existing design methods. We first introduce a transformation that converts the feedback control design problem into a bilinear matrix inequality (BMI) problem. Then, two iterative algorithms are proposed to compute the feedback controllers characterized by the BMI. Several simulation examples are given to demonstrate the advantages of the proposed design.

  4. Nonlinear Passive Control and Observer Design for Ships

    Directory of Open Access Journals (Sweden)

    Thor Inge Fossen

    2000-07-01

    Full Text Available Starting with passivity of the ambient water-ship system this article proceeds with nonlinear observer design, design of dynamic ship positioning systems and weather optimal positioning control systems exploiting the passivity properties of the vessel and the surrounding water. The article gives an overview of methods for passive ship control and observer design.

  5. 10 CFR 71.107 - Package design control.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 2 2010-01-01 2010-01-01 false Package design control. 71.107 Section 71.107 Energy... Assurance § 71.107 Package design control. (a) The licensee, certificate holder, and applicant for a CoC shall establish measures to assure that applicable regulatory requirements and the package design, as...

  6. Control-based operating system design

    CERN Document Server

    Leva, Alberto; Papadopoulos, AV; Terraneo, F

    2013-01-01

    This book argues that computer operating system components should be conceived from the outset as controllers, synthesised and assessed in the system-theoretical world of dynamic models, and then realised as control algorithms.

  7. Control of interface fracture in silicon nitride ceramics: influence of different rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Sun, E.Y.; Becher, P.F.; Waters, S.B.; Hsueh, Chun-Hway; Plucknett, K.P. [Oak Ridge National Lab., TN (United States); Hoffmann, M.J. [Karlsruhe Univ. (T.H.) (Germany). Inst. fuer Keramik im Maschinenbau

    1996-10-01

    The toughness of self-reinforced silicon nitride ceramics is improved by enhancing crack deflection and crack bridging mechanisms. Both mechanisms rely on the interfacial debonding process between the elongated {Beta}-Si{sub 3}N{sub 4} grains and the intergranular amorphous phases. The various sintering additives used for densification may influence the interfacial debonding process by modifying the thermal and mechanical properties of the intergranular glasses, which will result in different residual thermal expansion mismatch stresses; and the atomic bonding structure across the {Beta}-Si{sub 3}N{sub 4} glass interface. Earlier studies indicated that self-reinforced silicon nitrides sintered with different rare earth additives and/or different Y{sub 2}O{sub 3}:AI{sub 2}0{sub 3} ratios could exhibit different fracture behavior that varied from intergranular to transgranular fracture. No studies have been conducted to investigate the influence of sintering additives on the interfacial fracture in silicon nitride ceramics. Because of the complexity of the material system and the extremely small scale, it is difficult to conduct quantitative analyses on the chemistry and stress states of the intergranular glass phases and to relate the results to the bulk properties. The influence of different sintering additives on the interfacial fracture behavior is assessed using model systems in which {Beta}-Si{sub 3}N{sub 4}whiskers are embedded in SIAIRE (RE: rare-earth) oxynitride glasses. By systematically varying the glass composition, the role of various rare-earth additives on interfacial fracture has been examined. Specifically, four different additives were investigated: Al{sub 2}0{sub 3}, Y{sub 2}0{sub 3}, La{sub 2}O{sub 3}, and Yb{sub 2}O{sub 3}. In addition, applying the results from the model systems, the R- curve behavior of self-reinforced silicon nitride ceramics sintered with different Y{sub 2}0{sub 3}:AI{sub 2}0{sub 3} ratios was characterized.

  8. FUZZY LOGIC CONTROLLED CATHODIC PROTECTION CIRCUIT DESIGN

    OpenAIRE

    AKÇAYOL, M. Ali

    2010-01-01

    In this study, output voltage of automatic transformer-rectifier (TR) unit of impressed current cathodic protection has been controlled by using fuzzy logic controller. To prevent corrosion, voltage between the protection metal and the auxiliary anode has to be controlled on a desired level. Because soil resistance in the environment changes with humidity and soil characteristics, TRs must control the output voltage between protection metal and auxiliary anode automatically. In this study, a ...

  9. Cooperative adaptive cruise control: design and experiments

    NARCIS (Netherlands)

    Naus, G.; Vugts, R.; Ploeg, J.; Molengraft, R. van de; Steinbuch, M.

    2010-01-01

    The design of a CACC system and corresponding experiments are presented. The design targets string stable system behavior, which is assessed using a frequency-domain-based approach. Following this approach, it is shown that the available wireless information enables small inter-vehicle distances, wh

  10. Cooperative adaptive cruise control: design and experiments

    NARCIS (Netherlands)

    Naus, G.; Vugts, R.; Ploeg, J.; Molengraft, R. van de; Steinbuch, M.

    2010-01-01

    The design of a CACC system and corresponding experiments are presented. The design targets string stable system behavior, which is assessed using a frequency-domain-based approach. Following this approach, it is shown that the available wireless information enables small inter-vehicle distances, wh

  11. LMI–based robust controller design approach in aircraft multidisciplinary design optimization problem

    Directory of Open Access Journals (Sweden)

    Qinghua Zeng

    2015-07-01

    Full Text Available This article proposes a linear matrix inequality–based robust controller design approach to implement the synchronous design of aircraft control discipline and other disciplines, in which the variation in design parameters is treated as equivalent perturbations. Considering the complicated mapping relationships between the coefficient arrays of aircraft motion model and the aircraft design parameters, the robust controller designed is directly based on the variation in these coefficient arrays so conservative that the multidisciplinary design optimization problem would be too difficult to solve, or even if there is a solution, the robustness of design result is generally poor. Therefore, this article derives the uncertainty model of disciplinary design parameters based on response surface approximation, converts the design problem of the robust controller into a problem of solving a standard linear matrix inequality, and theoretically gives a less conservative design method of the robust controller which is based on the variation in design parameters. Furthermore, the concurrent subspace approach is applied to the multidisciplinary system with this kind of robust controller in the design loop. A multidisciplinary design optimization of a tailless aircraft as example is shown that control discipline can be synchronous optimal design with other discipline, especially this method will greatly reduce the calculated amount of multidisciplinary design optimization and make multidisciplinary design optimization results more robustness of flight performance.

  12. Effect of two intensive insulin therapy regimens on perioperative glycemic control in bone fracture patients with type 2 diabetes mellitus

    Institute of Scientific and Technical Information of China (English)

    DENG Wei; HUO Li-li; LAN Ling; L(U) Yan-wei; WANG Man-yi

    2013-01-01

    Background Currently,there are no uniform standards and methods for perioperative glycemic control in bone fracture patients with Type 2 diabetes mellitus (T2DM).We retrospectively analyzed the efficacy and safety of two intensive insulin therapy regimens administered to bone fracture patients with T2DM in the perioperative period,to explore the best method of achieving perioperative glycemic control.Methods A number of 159 bone fracture patients with T2DM were divided into two groups.One group (n=81) received multiple subcutaneous insulin injections (MSⅡ group) and the other (n=78) received continuous subcutaneous insulin infusion (CSⅡ group).Blood glucose (BG) levels,time to achieve glycemic target,insulin dosage,and the incidence of hypoglycemia and complications were compared between groups.Results Both regimens reduced BG to desired levels before surgery.The time to reach glycemic target in CSⅡ group (2.5 days) was significantly shorter than that in the MSII group (7.3 days; P<0.001).Mean insulin dosage in the CSⅡ group (0.66 IU·kg-1·d-1) was significantly lower than that in the MSⅡ group (0.74 IU·kg1·d-1; P=0.005),as were the incidences of hypoglycemia (15.4% vs 32.1%) and infection (6.4% vs.23.5%).Multiple regression analysis showed that the time to reach glycemia target was associated with the insulin therapy regimen and dosage.The insulin dosage on reaching glycemia target was positively associated with body mass index (BMI),diabetes mellitus course,glycated hemoglobin A1c (HbA1c),and β-hydroxybutyric acid,and was negatively associated with age.Conclusion The efficacy and safety of CSⅡ was superior to that achieved with MSⅡ,suggesting that CSⅡ should be considered as initial therapy to control perioperative BG in bone fracture patients with T2DM.

  13. Controls on sill and dyke-sill hybrid geometry and propagation in the crust: The role of fracture toughness

    Science.gov (United States)

    Kavanagh, J. L.; Rogers, B. D.; Boutelier, D.; Cruden, A. R.

    2017-02-01

    Analogue experiments using gelatine were carried out to investigate the role of the mechanical properties of rock layers and their bonded interfaces on the formation and propagation of magma-filled fractures in the crust. Water was injected at controlled flux through the base of a clear-Perspex tank into superposed and variably bonded layers of solidified gelatine. Experimental dykes and sills were formed, as well as dyke-sill hybrid structures where the ascending dyke crosses the interface between layers but also intrudes it to form a sill. Stress evolution in the gelatine was visualised using polarised light as the intrusions grew, and its evolving strain was measured using digital image correlation (DIC). During the formation of dyke-sill hybrids there are notable decreases in stress and strain near the dyke as sills form, which is attributed to a pressure decrease within the intrusive network. Additional fluid is extracted from the open dykes to help grow the sills, causing the dyke protrusion in the overlying layer to be almost completely drained. Scaling laws and the geometry of the propagating sill suggest sill growth into the interface was toughness-dominated rather than viscosity-dominated. We define KIc* as the fracture toughness of the interface between layers relative to the lower gelatine layer KIcInt / KIcG. Our results show that KIc* influences the type of intrusion formed (dyke, sill or hybrid), and the magnitude of KIcInt impacted the growth rate of the sills. KIcInt was determined during setup of the experiment by controlling the temperature of the upper layer Tm when it was poured into place, with Tm < 24 °C resulting in an interface with relatively low fracture toughness that is favourable for sill or dyke-sill hybrid formation. The experiments help to explain the dominance of dykes and sills in the rock record, compared to intermediate hybrid structures.

  14. LMI-BASED AERO-ENGINE CONTROLLER DESIGN

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The problem of analysis and synthesis of robust control is addressed in this work. The approach transferring the robust control design into Linear Matrix Inequality(LMI) is provided. The LMI standard structure of robust controller is also given and the controller is obtained through solving three LMIs. As an example, a robust control law is designed to the twin-spool turbojet engine system using the given approach. The result shows that LMI approach is feasible.

  15. Flight Control Design for a Tailless Aircraft Using Eigenstructure Assignment

    OpenAIRE

    Clara Nieto-Wire; Kenneth Sobel

    2011-01-01

    We apply eigenstructure assignment to the design of a flight control system for a wind tunnel model of a tailless aircraft. The aircraft, known as the innovative control effectors (ICEs) aircraft, has unconventional control surfaces plus pitch and yaw thrust vectoring. We linearize the aircraft in straight and level flight at an altitude of 15,000 feet and Mach number 0.4. Then, we separately design flight control systems for the longitudinal and lateral dynamics. We use a control allocation ...

  16. Damage control orthopaedics: Variability of construct design for external fixation of the lower extremity and implications on cost.

    Science.gov (United States)

    Logan, Catherine; Hess, Arthur; Kwon, John Y

    2015-08-01

    To evaluate relative cost of external fixator constructs applied for damage control purposes in a cohort of advanced orthopaedic trainees and orthopaedic staff traumatologists. We also sought to evaluate physicians' understanding of component cost. Participants were asked to apply an external fixator for three separate fracture patterns in damage control fashion. A total of 19 physicians (nine PGY-4 residents, five PGY-5 residents, two orthopaedic trauma fellows and three orthopaedic staff traumatologists) participated. Total construct cost was calculated. Participants provided an estimate of the cost of each component in a fill-in format survey. Main outcome measures included cost of external fixator construct applied and the estimated cost of external fixator components. Average whole sale cost of an external fixator construct was $5252 (±$1798). Of the three fracture types examined, the tibial plafond fracture external fixator construct on average cost the most, followed by the tibial plateau fracture and the femur fracture construct. The large ex-fix combination clamp was the major contributor to cost for each construct. The combination clamp may be substituted for a multi-pin clamp, resulting in significant cost savings. The self-drilling Schanz pin and the large ex-fix combination clamp were most highly underestimated (25% and 22% of their actual cost, respectively). Innumerous construct designs exist and even small changes can significantly impact cost. Knowledge of component cost is low among staff and trainees. Education of component cost is vital to allow adequate consideration of construct design prior to fixator application. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. EVALUATION OF RESULTS IN INTRAMEDULLARY FIXATION OF SUBTROCHANTERIC FRACTURE OF FEMUR WITH PROXIMAL FEMORAL NAILING (AO TYPE OF DESIGN

    Directory of Open Access Journals (Sweden)

    D. Nitin Reddy

    2016-08-01

    Full Text Available BACKGROUND Among the femoral shaft injuries, upper femoral fractures present a peculiar problem of securing effective neutralization of deforming forces. The mechanical stresses at this level are very high, as they occur at the junction between the trabecular and cortical zone and also because of the deforming forces due to peculiar muscle insertion to the proximal and distal fragments. The present study was conducted to assess the utility and effectiveness of Proximal Femoral Nail evolved by AO-ASIF in 1997, for various types of upper femoral fractures. MATERIAL AND METHOD The present study consists of the patients admitted to Orthopaedic Units of KIMS Hospital, between June 2012 and July 2014; 1267 fracture cases were treated in Department of Orthopaedics, Konaseema Institute of Medical Sciences, Amalapuram, during this period. Of these 264 patients were admitted for femoral fractures. Of the 264 femoral fractures, 18 patients above the age of 20 years with subtrochanteric fractures were included in this study. RESULT Reduction was good in 72.2% (13 of the cases. Acceptable reduction was achieved in 3 (16.6% patients. Poor reduction was noted in 2 (11.1% patients. One of them were of elderly age group and had poor outcome at final follow-up. SUMMARY AND CONCLUSION From this sample study, we conclude that Proximal Femoral Nail is a good implant for the treatment of subtrochanteric fractures of femur provided optimal reduction of the fracture and good positioning of the nail and screws are achieved.

  18. Modelling and Control Design of Unified Power Flow Controller for Various Control Strategies

    Directory of Open Access Journals (Sweden)

    T. Nireekshana

    2010-11-01

    Full Text Available Unified Power Flow Controller (UPFC is used to control the power flow in the transmission systems by controlling the impedance, voltage magnitude and phase angle. This controller offers advantages in terms of static and dynamic operation of the power system. It also brings in new challenges in power electronics and power system design. The basic structure of the UPFC consists of two voltage source inverter (VSI; where one converter is connected in parallel to the transmission line while the other is in series with the transmission line. The aim of the paper is to develop a control strategy for UPFC, modeling UPFC using MATLAB/SIMULINK and to analyze the control strategy to use the series voltage injection and shunt current injection for UPFC control. To simplify the design procedure we carry out the design for the series and shunt branches separately.In each case, a simple equivalent circuit represents the external system. The design has to be validated when the various subsystems are integrated.

  19. FPGA Fuzzy Controller Design for Magnetic Ball Levitation

    Directory of Open Access Journals (Sweden)

    Basil Hamed

    2012-09-01

    Full Text Available this paper presents a fuzzy controller design for nonlinear system using FPGA. A magnetic levitation system is considered as a case study and the fuzzy controller is designed to keep a magnetic object suspended in the air counteracting the weight of the object. Fuzzy controller will be implemented using FPGA chip. The design will use a high-level programming language HDL for implementing the fuzzy logic controller using the Xfuzzy tools to implement the fuzzy logic controller into HDL code. This paper, advocates a novel approach to implement the fuzzy logic controller for magnetic ball levitation system by using FPGA.

  20. Design of Controllers for Continuous Stirred Tank Reactor

    Directory of Open Access Journals (Sweden)

    Somasundaram Deepa

    2015-02-01

    Full Text Available The objective of the project is to design various controllers for temperature control in Continuous Stirred Tank Reactor (CSTR systems. Initially Zeigler-Nichols, modified Zeigler-Nichols, Tyreus-Luyben, Shen-Yu and IMC based method of tuned Proportional Integral (PI controller is designed and comparisons are made with Fuzzy Logic Controller. Simulations are carried out and responses are obtained for the above controllers. Maximum peak overshoot, Settling time, Rise time,  ISE, IAE  are chosen as performance index. From the analysis it is found that the Fuzzy Logic Controller  is a promising controller than the conventional controllers.

  1. Automatic control system design of laser interferometer

    Science.gov (United States)

    Lu, Qingjie; Li, Chunjie; Sun, Hao; Ren, Shaohua; Han, Sen

    2015-10-01

    There are a lot of shortcomings with traditional optical adjustment in interferometry, such as low accuracy, time-consuming, labor-intensive, uncontrollability, and bad repetitiveness, so we treat the problem by using wireless remote control system. Comparing to the traditional method, the effect of vibration and air turbulence will be avoided. In addition the system has some peculiarities of low cost, high reliability and easy operation etc. Furthermore, the switching between two charge coupled devices (CCDs) can be easily achieved with this wireless remote control system, which is used to collect different images. The wireless transmission is achieved by using Radio Frequency (RF) module and programming the controller, pulse width modulation (PWM) of direct current (DC) motor, real-time switching of relay and high-accuracy displacement control of FAULHABER motor are available. The results of verification test show that the control system has good stability with less than 5% packet loss rate, high control accuracy and millisecond response speed.

  2. Project Design Concept for Monitoring and Control System

    Energy Technology Data Exchange (ETDEWEB)

    MCGREW, D.L.

    2000-10-02

    This Project Design Concept represents operational requirements established for use in design the tank farm Monitoring and Control System. These upgrades are included within the scope of Project W-314, Tank Farm Restoration and Safe Operations.

  3. Fault tolerant control design for hybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hao; Jiang, Bin [Nanjing University of Aeronautics and Astronautics, Nanjing (China); Cocquempot, Vincent [Universite des Sciences et Technologies de Lille, Villeneuve d' Ascq (France)

    2010-07-01

    This book intends to provide the readers a good understanding on how to achieve Fault Tolerant Control goal of Hybrid Systems. The book can be used as a reference for the academic research on Fault Tolerant Control and Hybrid Systems or used in Ph.D. study of control theory and engineering. The knowledge background for this monograph would be some undergraduate and graduate courses on Fault Diagnosis and Fault Tolerant Control theory, linear system theory, nonlinear system theory, Hybrid Systems theory and Discrete Event System theory. (orig.)

  4. Fast Algorithms for Hybrid Control System Design

    Science.gov (United States)

    2007-11-02

    Controls for Petri Nets with Unobservable Transitions", Proceedings of the 1997 American Control Conference, pp. 2354- 2358, Albuquerque, New Mexico , June...Automation Conference, April 20-25, 1997, 1997, Albuquerque New Mexico . - Invited Speaker at special session on "Intelligent Control Systems" at the 3rd...0 (11) Moreover, if either (hence, both) of these statements hold, then one controller that renders iVa (Ji(P, K)) < 7 is ffiven by A + B2J- aYaC2

  5. [Comparison of clinical effectiveness of thoracic epidural and intravenous patient-controlled analgesia for the treatment of rib fractures pain in intensive care unit].

    Science.gov (United States)

    Topçu, Ismet; Ekici, Zeynep; Sakarya, Melek

    2007-07-01

    The results of thoracic epidural and systemic patient controlled analgesia practice were evaluated retrospectively in patients with thoracic trauma. Patients who were admitted to the intensive care unit between 1997 and 2003, with a diagnosis of multiple rib fractures related to thoracic trauma were evaluated retrospectively. Data were recorded from 49 patients who met the following criteria; three or more rib fractures, initiation of PCA with I.V. phentanyl or thoracic epidural analgesia with phentanyl and bupivacaine. There were no significant differences between the groups concerning injury severity score. APACHE II score (8.1+/-1.6 and 9.2+/-1.7) and the number of rib fractures (4+/-1.1 and 6.8+/-2.7) were higher in thoracic epidural analgesia group (pPain scores of patients who received thoracic epidural analgesia were significantly lower as from 6th hour during whole therapy (prib fractures who require intensive care.

  6. Patterns of osteocytic endothelial nitric oxide synthase expression in the femoral neck cortex: differences between cases of intracapsular hip fracture and controls.

    Science.gov (United States)

    Loveridge, N; Fletcher, S; Power, J; Caballero-Alías, A M; Das-Gupta, V; Rushton, N; Parker, M; Reeve, J; Pitsillides, A A

    2002-06-01

    Evidence indicates that extensive amalgamation of adjacent resorbing osteons is responsible for destroying the microstructural integrity of the femoral neck's inferior cortex in osteoporotic hip fracture. Such osteonal amalgamation is likely to involve a failure to limit excessive resorption, but its mechanistic basis remains enigmatic. Nitric oxide (NO) inhibits osteoclastic bone destruction, and in normal bone cells its generation by endothelial nitric oxide synthase (eNOS, the predominant bone isoform) is enhanced by mechanical stimuli and estrogen, which both protect against fracture. To determine whether eNOS expression in osteocytes reflects their proposed role in regulating remodeling, we have examined patterns of osteocyte eNOS immunolabeling in the femoral neck cortex of seven cases of hip fracture and seven controls (females aged 68-96 years). The density of eNOS+ cells (mm(-2)) was 53% lower in the inferior cortex of the fracture cases (p bone.

  7. Application of dimensional analysis in systems modeling and control design

    CERN Document Server

    Balaguer, Pedro

    2013-01-01

    Dimensional analysis is an engineering tool that is widely applied to numerous engineering problems, but has only recently been applied to control theory and problems such as identification and model reduction, robust control, adaptive control, and PID control. Application of Dimensional Analysis in Systems Modeling and Control Design provides an introduction to the fundamentals of dimensional analysis for control engineers, and shows how they can exploit the benefits of the technique to theoretical and practical control problems.

  8. Improved forwarding control design method and its application

    Institute of Scientific and Technical Information of China (English)

    Chen Yimei; Han Zhengzhi; Cai Xiushan

    2006-01-01

    Integrator forwarding is a recursive nonlinear design technique for the stabilization of feed-forward systems.However, this method still has some limitation. An improved design method is proposed to extend the field of application of this technique. This method is used to design a stabilizer for the inertia wheel pendulum system. Moreover, it is shown that the control Lyapunov function which is obtained from this method can also be used to design a globally asymptotically stabilizing controller with optimality.

  9. Committee III.2 Fatigue and Fracture

    DEFF Research Database (Denmark)

    Brennan, F. P.; Branner, Kim; den Besten, J.H.

    2015-01-01

    Concern for crack initiation and growth under cyclic loading as well as unstable crack propagation and tearing in ship and offshore structures. Due attention shall be paid to practical application and statistical description of fracture control methods in design, fabrication and service...

  10. Integration of Design and Control Through Model Analysis

    DEFF Research Database (Denmark)

    Russel, Boris Mariboe; Henriksen, Jens Peter; Jørgensen, Sten Bay;

    2000-01-01

    A systematic analysis of the process model is proposed as a pre-solution step for integration of design and control problems. It is shown that the same set of process (control) variables and design (manipulative) variables is employed with different objectives in design and control. Analysis of t...... processes with mass and/or energy recycle. (C) 2000 Elsevier Science Ltd. All rights reserved....

  11. Backstepping Designs for Aircraft Control - What is there to Gain?

    OpenAIRE

    Härkegård, Ola

    2001-01-01

    Aircraft flight control design is traditionally based on linear control theory, due to the existing wealth of tools for linear design and analysis. However, in order to achieve tactical advantages, modern fighter aircraft strive towards performing maneuvers outside the region where the dynamics of flight are linear, and the need for nonlinear tools arises. In this paper, backstepping is proposed as a possible framework for nonlinear flight control design. Its capabilities of handling five maj...

  12. Robust Control Mixer Method for Reconfigurable Control Design Using Model Matching Strategy

    DEFF Research Database (Denmark)

    Yang, Zhenyu; Blanke, Mogens; Verhagen, Michel

    2007-01-01

    A novel control mixer method for recon¯gurable control designs is developed. The proposed method extends the matrix-form of the conventional control mixer concept into a LTI dynamic system-form. The H_inf control technique is employed for these dynamic module designs after an augmented control sy...

  13. Unified power flow controller: Modeling, stability analysis, control strategy and control system design

    Science.gov (United States)

    Sreenivasachar, Kannan

    2001-07-01

    Unified power flow controller (UPFC) has been the most versatile Flexible AC Transmission System (FACTS) device due to its ability to control real and reactive power flow on transmission lines while controlling the voltage of the bus to which it is connected. UPFC being a multi-variable power system controller it is necessary to analyze its effect on power system operation. To study the performance of the UPFC in damping power oscillations using PSCAD-EMTDC software, a de-coupled control system has been designed for the shunt inverter to control the UPFC bus voltage and the DC link capacitor voltage. The series inverter of a UPFC controls the real power flow in the transmission line. One problem associated with using a high gain PI controller (used to achieve fast control of transmission line real power flow) for the series inverter of a UPFC to control the real power flow in a transmission line is the presence of low damping. This problem is solved in this research by using a fuzzy controller. A method to model a fuzzy controller in PSCAD-EMTDC software has also been described. Further, in order to facilitate proper operation between the series and the shunt inverter control system, a new real power coordination controller has been developed and its performance was evaluated. The other problem concerning the operation of a UPFC is with respect to transmission line reactive power flow control. Step changes to transmission line reactive power references have significant impact on the UPFC bus voltage. To reduce the adverse effect of step changes in transmission line reactive power references on the UPFC bus voltage, a new reactive power coordination controller has been designed. Transient response studies have been conducted using PSCAD-EMTDC software to show the improvement in power oscillation damping with UPFC. These simulations include the real and reactive power coordination controllers. Finally, a new control strategy has been proposed for UPFC. In this

  14. Symbolics in control design: prospects and research issues

    DEFF Research Database (Denmark)

    Christensen, Anders

    1994-01-01

    The symbolic processor is targeted as a novel basic service in computer aided control system design. Basic symbolic tools are exemplified. A design process model is formulated for control design, with subsets manipulator, tools, target and goals. It is argued, that symbolic processing will give...... substantial contributions to future design environments, as it provides flexibility of representation not possible with traditional numerics. Based on the design process, views on research issues in the incorporation of symbolic processing into traditional numerical design environments are given...

  15. Safety and efficacy of vertebroplasty in the treatment of osteoporotic vertebral compression fractures: a prospective multicenter international randomized controlled study

    Science.gov (United States)

    Leali, Paolo Tranquilli; Solla, Federico; Maestretti, Gianluca; Balsano, Massimo; Doria, Carlo

    2016-01-01

    Summary Background Vertebral compression fractures (VCFs) treated non-operatively can diminish function and quality of life, and lead to chronic health effects. The short-term safety and effectiveness of vertebroplasty for symptomatic VCFs are well-documented, but long-term follow-up is needed. Purpose The aim of this paper was to analyse a multicenter international experience of 200 compression fractures treated with percutaneous vertebroplasty (VP) and compare the results of this procedure with the result of 200 patients treated conservatively. To estimate cost-effectiveness of VP compared to conservative care in terms of: pain reduction, quality of life, complications, secondary fractures and mortality. Materials and methods 400 patients have been enrolled in a prospective randomized controlled study with painful VCFs with bone edema on MR imaging, local back pain for 6 weeks or less, osteoporosis and aged 55 years or older; after obtaining informed consent patients are included and randomized for VP or conservative care. Before treatment and at follow-up with regular intervals during 1-year period were administered to patients standard questionnaires addressing: clinical symptoms, pain medication, Visual Analogue Scale (VAS) score for pain, Oswestry Disability Index (ODI) score to evaluate functional activity. Results 200 patients treated with PV compared with 200 patients treated conservatively had significantly better VAS and used less analgesics 1 day after treatment. Twenty-four hours after VP, there was a reduction in pain scores and an improvement in physical functions, whereas remain unchanged in the patients treated conservatively. Conclusions Pain relief and improvement of mobility and function after PV is immediate and significantly better in the short term compared with non-surgical care treatment. PMID:28228788

  16. Effect of occupational therapy on functional and emotional outcomes after hip fracture treatment: a randomized controlled trial.

    Science.gov (United States)

    Martín-Martín, Lydia M; Valenza-Demet, Gerald; Jiménez-Moleón, José Juan; Cabrera-Martos, Irene; Revelles-Moyano, Francisco Javier; Valenza, Marie Carmen

    2014-06-01

    To explore whether an occupational therapy intervention combined with physiotherapy rehabilitation improved hip fracture patient outcomes regarding emotional distress, fatigue, independence and function. Randomized controlled trial. Inpatient trauma ward in a rehabilitation and trauma hospital. One hundred and twenty-two patients admitted into hospital for hip fracture. Patients were randomly assigned to a standard care group (SC, n = 61) or a combined treatment group (CT, n = 61). The SC group received conventional hospital care for hip fracture patients and the CT group underwent occupational therapy as well. Patients' emotional distress (GHQ-28), perceived fatigue (the first item of the BASDAI using a 0-100 visual analogue scale scale), level of independence (Modified Barthel Index) and function (Harris Hip Score) were measured at baseline and one, three and six months after the intervention. Patients in the CT group experienced a considerable decrease of emotional distress at three and six months (p = 0.005 and p < 0.001, respectively). A between-group analysis showed significant differences in emotional distress at one, three and six months (p < 0.001). Although fatigue levels decreased in the SC group, the most significant decline was reported by the CT group at six months (p < 0.001, mean difference = 14 points). Regarding independence level, significant differences were found within groups at each stage, but also between groups at one month in favor of the CT group. Function improved in both groups compared with baseline (p < 0.001), but no significant differences were found in functionality between groups. Although both groups reported significant improvements, patients in the CT group had better scores in emotional distress and dependence throughout follow-up and better scores in all measures at six months. © The Author(s) 2013.

  17. Case-control study of high-speed exercise history of Thoroughbred and Quarter Horse racehorses that died related to a complete scapular fracture.

    Science.gov (United States)

    Vallance, S A; Entwistle, R C; Hitchens, P L; Gardner, I A; Stover, S M

    2013-05-01

    Identification of exercise history patterns that are related to catastrophic scapular fracture will facilitate prevention of racehorse fatalities. To determine if exercise patterns are associated with scapular fracture in Thoroughbred (TB) and Quarter Horse (QH) racehorses. High-speed exercise histories for 65 TB and 26 QH racehorses that had a complete scapular fracture (cases) and 2 matched control racehorses were retrospectively studied. Exercise variables were created from lifetime race and official timed workout reports. Associations between exercise variables and scapular fracture were investigated using conditional logistic regression. Thoroughbreds with a scapular fracture had a greater number of workouts, events (combined works and races), and mean event distances than QHs with a scapular fracture. Quarter Horses worked less frequently and accumulated distance at a lower rate than TBs. Breed differences were not found for career race number or length, time between races or lay-up variables for horses with ≥1 lay-up. For both breeds, cases had fewer events, lower recent accumulated distance and fewer active days in training than controls; however, a subset of TB cases with >10 events since lay-up had a longer active career than controls. For QHs that had a lay-up, total and mean lay-up times were greater for cases than controls. Multivariable models revealed that odds ratios (OR) of scapular fracture were greater for TBs that had not yet raced (OR = 23.19; 95% confidence interval (CI) 3.03-177.38) and lower for QHs with more events (OR = 0.71; 95% CI 0.54-0.94). Racehorses that are in early high-speed training but behind that of their training cohort should be examined for signs of scapular stress remodelling. Quarter Horses that had a prolonged lay-up and TBs that have endured high-speed training for a longer duration than that of their training cohort also were at greater risk. © 2012 EVJ Ltd.

  18. fpga controller design and simulation of a portable dough mixing

    African Journals Online (AJOL)

    In this paper, the design and simulation of a Dough Mixer Controller (DMC) with Proportional ... Keywords: FPGA, VHDL, PID controller, Pulse Width Modulation, Full H-Bridge DC motor driver. 1. ...... parative Analysis among DSP and FPGA-.

  19. A methodological approach to designing sewer system control

    DEFF Research Database (Denmark)

    Mollerup, Ane Loft

    for this thesis was therefore the wish for a methodological approach to sewer system control design. Using a case study the following research hypothesis was tested in this thesis: Using classical and modern control theory, a methodological approach can be derived for designing sewer system control. This can aid...... urban drainage planner and other professionals in the planning phase of sewer system con-trol design and effectively contribute to find novel control solution. It was investigated if the established methodology used in classic control the-ory for process control design can be applied meaningfully....... This was not unexpected, since the true potential of having optimisation arises, when a system has many control loops with limit-ing constraints and/or changing prioritisation between them. The results showed that for small sewer systems, where the complexity is limited, it is not necessarily the best option to implement...

  20. Subduction of Fracture Zones control mantle melting and geochemical signature above slabs

    Science.gov (United States)

    Constantin Manea, Vlad; Leeman, William; Gerya, Taras; Manea, Marina; Zhu, Guizhi

    2014-05-01

    The geochemistry of arc volcanics proximal to oceanic fracture zones (FZs) is consistent with higher than normal fluid inputs to arc magma sources. Here, enrichment of boron (B/Zr) in volcanic arc lavas is used to evaluate relative along-strike inputs of slab-derived fluids in the Aleutian, Andean, Cascades, and Trans-Mexican arcs. Significant B/Zr spikes coincide with subduction of prominent FZs in the relatively cool Aleutian and Andean subduction zones, but not in the relatively warm Cascadia and Mexican subduction zones, suggesting that FZ subduction locally enhances fluid introduction beneath volcanic arcs, and retention of fluids to sub-arc depths diminishes with subduction zone thermal gradient. Geodynamic treatments of lateral inhomogeneities in subducting plates have not previously considered how FZs may influence the melt and fluid distribution above the slab. Using high-resolution three-dimensional coupled petrological-thermomechanical numerical simulations of subduction, we show that fluids, including melts and water, concentrate in areas where fracture zones are subducted, resulting in along-arc variability in magma source compositions and processes.

  1. Effect of pathologic fractures on survival in multiple myeloma patients: a case control study

    Directory of Open Access Journals (Sweden)

    Yilmaz Mustafa

    2008-06-01

    Full Text Available Abstract Background Multiple Myeloma (MM is a B cell neoplasm characterized by the clonal proliferation of plasma cells. Skeletal complications are found in up to 80% of myeloma patients at presentation and are major cause of morbidity. Methods 49 patients were enrolled with MM admitted to Black Sea Technical University Hospital between 2002–2005. Pathologic fractures (PFs were determined and the patients with or without PF were followed up minumum 3 years for survival analysis. Results PF was observed in 24 patients (49% and not observed in 25 patients (51%. The risk of death was increased in the patients with PF compared with patients who had no fractures. While overall survival was 17.6 months in the patients with PFs, it was 57.3 months in the patients with no PFs. Conclusion These findings suggest that PFs may induce reduced survival and increased mortality in the MM patients, however, larger sample size is essential to draw clearer conclusions added to these data.

  2. Design requirement on KALIMER control rod assembly duct

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, W.; Kang, H. Y.; Nam, C.; Kim, J. O.; Kim, Y. J

    1998-03-01

    This document establishes the design guidelines which are needs for designing the control rod assembly duct of the KALIMER as design requirements. it describes control rod assembly duct of the KALIMER and its requirements that includes functional requirements, performance requirements, interfacing systems, design limits and strength requirements, seismic requirements, structural requirements, environmental requirements, reliability and safety requirements, standard and codes, QA programs, and other requirements. The control rod system consists of three parts, which are drive mechanism, drive-line, and absorber bundle. This report deals with the absorber bundle and its outer duct only because the others are beyond the scope of fuel system design. The guidelines for design requirements intend to be used for an improved design of the control rod assembly duct of the KALIMER. (author). 19 refs.

  3. Controller for solar heating-design package

    Science.gov (United States)

    1979-01-01

    Report contains performance specifications and detailed drawings for two instruments: (1) differential controller, and (2) temperature monitor, for solar-powered water-heating systems. Included in package are schematics, wiring diagrams, test procedures, and parts list.

  4. Sequence and Chance: Design and control methods for entertainment robots

    DEFF Research Database (Denmark)

    Jochum, Elizabeth Ann; Millar, Philip; Nuñez, David

    2016-01-01

    This paper describes innovative approaches to the design and control of entertainment robots. Live performance is a useful testbed for developing and evaluating what makes robots expressive [10] [13] [18]; it is also a platform for designing creative solutions for robot design and control...... mechanisms for believable and expressive robots. Entertainment robots require creative approaches to robot design and control, including motion planning, coordination and hybrid control systems. The exigencies of live performance require situated, embodied robots to move autonomously or semi......-autonomously alongside human actors and in coordination with human operators. Using design and control approaches from traditional puppetry, engineers can design creative solutions for generating expressive robot motion. We outline some of these creative approaches as they are used in live theatre performances...

  5. Design of dual DC motor control system based on DSP

    Science.gov (United States)

    Shi, Peicheng; Wang, Suo; Xu, Zengwei; Xiao, Ping

    2017-08-01

    Multi-motor control systems are widely used in actual production and life, such as lifting stages, robots, printing systems. This paper through serial communication between PC and DSP, dual DC motor control system consisting of PC as the host computer, DSP as the lower computer with synchronous PWM speed regulation, commutation and selection functions is designed. It sends digital control instructions with host computer serial debugger to lower computer, to instruct the motor to complete corresponding actions. The hardware and software design of the control system are given, and feasibility and validity of the control system are verified by experiments. The expected design goal is achieved.

  6. Controller design for TS models using delayed nonquadratic Lyapunov functions.

    Science.gov (United States)

    Lendek, Zsofia; Guerra, Thierry-Marie; Lauber, Jimmy

    2015-03-01

    In the last few years, nonquadratic Lyapunov functions have been more and more frequently used in the analysis and controller design for Takagi-Sugeno fuzzy models. In this paper, we developed relaxed conditions for controller design using nonquadratic Lyapunov functions and delayed controllers and give a general framework for the use of such Lyapunov functions. The two controller design methods developed in this framework outperform and generalize current state-of-the-art methods. The proposed methods are extended to robust and H∞ control and α -sample variation.

  7. Constrained linear control design of continuous bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Tarbouriech, S.; Queinnec, I.

    1994-12-31

    The control problem of a continuous bio-process is expressed in terms of stabilization and disturbances attenuation of an uncertain linear system under state and control constraints. A static output feedback is realized to obtain a suitable Eigen-structure assignment in closed-loop; then a positively invariant set of admissible initial states is determined by using cones properties, in order to respect the constraints. (authors) 19 refs.

  8. Nonlineat observer-controller design for dynamic positioning of ships

    Institute of Scientific and Technical Information of China (English)

    何黎明; 田作华; 施颂椒

    2004-01-01

    The main focus is nonlinear model-based dynamic positioning (DP) control system design. A nonlinear uniform global exponential stability (UGES) observer produces noise-free estimates of the position, the slowly varying environmental disturbances and the velocity, which are used in a proportional-derivative (PD) + feedforward control law. The stability of this observer-controller system is proved by introducing a specific nonlinear cascaded system. The simulation results have successfully demonstrated the performance of designed DP control system.

  9. Analysis and design of controllers for a double inverted pendulum

    DEFF Research Database (Denmark)

    Niemann, Hans Henrik; Poulsen, J K

    2003-01-01

    A physical control problem is studied with the μ methodology. The issues of modelling, uncertainty modelling, performance specification, controller design and laboratory implementation are discussed. The laboratory experiment is a double inverted pendulum placed on a cart. The limitations in the ...... in the system with respect to performance are the limitation in the control signal and the limitation of the movement of the chart. It is shown how these performance limitation will effect the design of a μ controller for the system....

  10. Multivariable robust digital controller design by convex optimization

    OpenAIRE

    2004-01-01

    The dissertation is essentially concerned with methods of robust digital multivariable and monovariable controller design. For controller desing, a linear discrete-time model of plant to be controlled is used. The controller robustness is treated by sensitivity frequency analysis(sensitivity is transfer function/matrix of closed loop). Correspondingly to H∞ design, the singular values of frequency responses are used for the analysis.The work is divided into five parts. The first part concerns...

  11. Fracture mechanics in new designed power module under thermo-mechanical loads

    Directory of Open Access Journals (Sweden)

    Durand Camille

    2014-06-01

    Full Text Available Thermo-mechanically induced failure is a major reliability issue in the microelectronic industry. On this account, a new type of Assembly Interconnected Technology used to connect MOSFETs in power modules has been developed. The reliability is increased by using a copper clip soldered on the top side of the chip, avoiding the use of aluminium wire bonds, often responsible for the failure of the device. Thus the new designed MOSFET package does not follow the same failure mechanisms as standard modules. Thermal and power cycling tests were performed on these new packages and resulting failures were analyzed. Thermo-mechanical simulations including cracks in the aluminium metallization and intermetallics (IMC were performed using Finite Element Analysis in order to better understand crack propagation and module behaviour.

  12. Ultrasound-guided femoral nerve block for pain control in an infant with a femur fracture due to nonaccidental trauma.

    Science.gov (United States)

    Frenkel, Oron; Mansour, Karim; Fischer, Jason W J

    2012-02-01

    A 3-month-old infant girl was transferred to our emergency department (ED) with a subtrochanteric femoral neck fracture due to nonaccidental trauma. She received multiple doses of parenteral analgesics both before arrival and in our ED. We performed an ultrasound-guided femoral nerve block using 2.0 mL of 0.25% bupivicaine (approximately 1.25 mg/kg) before placing the patient in a Pavlik harness. Successful pain control was achieved within 15 minutes of the procedure allowing pain-free manipulation of the affected extremity. The patient required only a single dose of parenteral narcotics during the ensuing 18 hours. To our knowledge, this is the first report of an ultrasound-guided femoral nerve block used in the ED for pain control in a pediatric patient.

  13. Flight Controller Design of Transport Airdrop

    Institute of Scientific and Technical Information of China (English)

    CHEN Jie; SHIZhongke

    2011-01-01

    During airdrop of heavy load,the flight paramctcrs vary continuously as the load moves in the hold,and change suddenly when the load drops out.This process deteriorates the flight quality and control characteristic as the load becomes heavier.Based on the simplified airdrop flight equations,the backstepping and switch control methods are developed to tackle the flight state holding and disturbance/uncertainty(such as large scale flight condition,pilot manipulation error,system measure delay,etc.)attenuation problem in this paper.Moreover,these methods can be used as a reference for pilot manipulating during airdrop.With the backstepping theory,an adaptive controller is synthesized for the purpose of stabilizing the transport when the load moves in the hold,and then a coordinated switch control method is used to control the aircraft when the condition jumps from the existence of load at the rear of fuselage to no load in the fuselage.Simulation results show that the proposed controllers not only provide effective state holding during airdrop,but also achieve robust performance within wide flight conditions.

  14. Pulsed Electromagnetic Fields in the treatment of fresh scaphoid fractures. A multicenter, prospective, double blind, placebo controlled, randomized trial.

    NARCIS (Netherlands)

    Hannemann, P.; Gottgens, K.W.; Wely, B.J. van; Kolkman, K.A.; Werre, A.J.; Poeze, M.; Brink, P.R.

    2011-01-01

    BACKGROUND: The scaphoid bone is the most commonly fractured of the carpal bones. In the Netherlands 90% of all carpal fractures is a fracture of the scaphoid bone. The scaphoid has an essential role in functionality of the wrist, acting as a pivot. Complications in healing can result in poor

  15. Pulsed Electromagnetic Fields in the treatment of fresh scaphoid fractures. A multicenter, prospective, double blind, placebo controlled, randomized trial.

    NARCIS (Netherlands)

    Hannemann, P.; Gottgens, K.W.; Wely, B.J. van; Kolkman, K.A.; Werre, A.J.; Poeze, M.; Brink, P.R.

    2011-01-01

    BACKGROUND: The scaphoid bone is the most commonly fractured of the carpal bones. In the Netherlands 90% of all carpal fractures is a fracture of the scaphoid bone. The scaphoid has an essential role in functionality of the wrist, acting as a pivot. Complications in healing can result in poor functi

  16. Active noise control in fuselage design

    NARCIS (Netherlands)

    Krakers, L.A.; Tooren, M.J.L. van; Beukers, A.; Berkhof, A.P.; Goeje, M.P. de

    2003-01-01

    To achieve comfortable noise levels inside the passenger cabin, sound damping measures have to be taken to improve the sound insulation properties of the bare airframe. Usually the sound insulation requirements of a passenger cabin are met after the mechanical design of the fuselage structure is alr

  17. Analytical design of PI controller for AQM with robustness adjustability

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Based on a linearized TCP/AOM model,a new proportional integral(PI)controller design approach is proposed.This analytical approach applies H∞ optimization and internal model control(IMC)theory to design active queue management(AQM)routers that support transmission control protocol(TCP)flows.The most important feature of the proposed scheme lies in that it can be explicitly tuned with a single parameter for the trade-off between performance and stability of the AOM control system.It is thus flexible and easy to use in design.The proposed method and the designed PI controller are verified and compared with other existing AOM schemes using ns-2 simulator.The results show the advantages of the new PI controller design approach for AQM routers supporting TCP flows.

  18. CANDIDATE GENE ANALYSIS IN ISRAELI SOLDIERS WITH STRESS FRACTURES

    Directory of Open Access Journals (Sweden)

    Ran Yanovich

    2012-03-01

    Full Text Available To investigate the association of polymorphisms within candidate genes which we hypothesized may contribute to stress fracture predisposition, a case-control, cross- sectional study design was employed. Genotyping 268 Single Nucleotide Polymorphisms- SNPs within 17 genes in 385 Israeli young male and female recruits (182 with and 203 without stress fractures. Twenty-five polymorphisms within 9 genes (NR3C1, ANKH, VDR, ROR2, CALCR, IL6, COL1A2, CBG, and LRP4 showed statistically significant differences (p < 0.05 in the distribution between stress fracture cases and non stress fracture controls. Seventeen genetic variants were associated with an increased stress fracture risk, and eight variants with a decreased stress fracture risk. None of the SNP associations remained significant after correcting for multiple comparisons (false discovery rate- FDR. Our findings suggest that genes may be involved in stress fracture pathogenesis. Specifically, the CALCR and the VDR genes are intriguing candidates. The putative involvement of these genes in stress fracture predisposition requires analysis of more cases and controls and sequencing the relevant genomic regions, in order to define the specific gene mutations

  19. Design of Tension Controller with Electronic Gearing for Rapier Looms

    Institute of Scientific and Technical Information of China (English)

    郭帅; 何永义; 周其洪; 方明伦

    2004-01-01

    The declining cost of precision motion controls allows economical replacement of mechanical drives with electronic versions in weaving processes. This paper describes the design of tension controller with electronic gearing. A control algorithm of PID is also introduced in order to improve performance of the tension controller. Finally, experimental results and conclusions are given.

  20. Design of Industrial Robotic Controller Based on DSP

    Institute of Scientific and Technical Information of China (English)

    谈世哲; 杨汝清

    2003-01-01

    This paper describes the design of industrial robot controller based on the DSP technology. Robotic real time control is realized by PC and DSP motion control card and this method improves the performance of robotic controller. Finally this paper gives some experiment results and conclusion.

  1. Feedback Controller Design for the Synchronization of Boolean Control Networks.

    Science.gov (United States)

    Liu, Yang; Sun, Liangjie; Lu, Jianquan; Liang, Jinling

    2016-09-01

    This brief investigates the partial and complete synchronization of two Boolean control networks (BCNs). Necessary and sufficient conditions for partial and complete synchronization are established by the algebraic representations of logical dynamics. An algorithm is obtained to construct the feedback controller that guarantees the synchronization of master and slave BCNs. Two biological examples are provided to illustrate the effectiveness of the obtained results.

  2. Mathematical and computational analyses of cracking formation fracture morphology and its evolution in engineering materials and structures

    CERN Document Server

    Sumi, Yoichi

    2014-01-01

    This book is about the pattern formation and the evolution of crack propagation in engineering materials and structures, bridging mathematical analyses of cracks based on singular integral equations, to computational simulation of engineering design. The first two parts of this book focus on elasticity and fracture and provide the basis for discussions on fracture morphology and its numerical simulation, which may lead to a simulation-based fracture control in engineering structures. Several design concepts are discussed for the prevention of fatigue and fracture in engineering structures, including safe-life design, fail-safe design, damage tolerant design. After starting with basic elasticity and fracture theories in parts one and two, this book focuses on the fracture morphology that develops due to the propagation of brittle cracks or fatigue cracks.   In part three, the mathematical analysis of a curved crack is precisely described, based on the perturbation method. The stability theory of interactive ...

  3. Postoperative red blood cell transfusion strategy in frail anemic elderly with hip fracture. A randomized controlled trial.

    Science.gov (United States)

    Gregersen, Merete

    2016-04-01

    Hip fracture in the elderly is associated with poor recovery from physical disability and mortality. Perioperative blood loss is common, and anemia might be fatal in the frail elderly. Red blood cell transfusions might increase the risk of infection. In an observational study, a liberal transfusion strategy with hemoglobin (Hb) target of 7 mmol/l (11.3 g/dl) seemed to improve survival in nursing home residents with hip fracture compared to the recommended restrictive strategy with a Hb target of 6 mmol/l (9.7 g/dl) according to the Danish Health Authority. Our aim was to compare these two strategies in the frail elderly in a randomized controlled trial on the outcomes: recovery from physical disabilities, mortality, infection, infection biomarkers, and overall Quality of Life (OQoL). We included 284 elderly admitted to hospital for surgical hip fracture repair from nursing homes or sheltered housing facilities. The anemic patients were assigned postoperatively to the liberal or the restrictive transfusion strategy. Randomization divided each transfusion group into two equal blocks with regard to type of the residence. Hb was measured daily during the first three postoperative days, at least once during the following 4-6 days, then at least once a week during the subsequent three weeks. The transfusions were administered according to group assignments, but no later than 24 hours after the Hb determination, one unit at a time, and no more than two units per day. The intervention lasted for 30 days after surgery. Outcome measurements were performed on days 10, 30, 90, and 365. Blinded assessors evaluated physical performance and OQoL. The liberal transfusion strategy did not improve recovery from physical disabilities, mortality, infection rate, or OQoL compared to the restrictive strategy. However, in nursing home residents, 90-day mortality rate (20%) following the liberal strategy was statistically significantly lower than that (36%) after the restrictive strategy

  4. Adaptive Controller Design for Faulty UAVs via Quantum Information Technology

    Directory of Open Access Journals (Sweden)

    Fuyang Chen

    2012-12-01

    Full Text Available In this paper, an adaptive controller is designed for a UAV flight control system against faults and parametric uncertainties based on quantum information technology and the Popov hyperstability theory. First, considering the bounded control input, the state feedback controller is designed to make the system stable. The model of adaptive control is introduced to eliminate the impact by the uncertainties of system parameters via quantum information technology. Then, according to the model reference adaptive principle, an adaptive control law based on the Popov hyperstability theory is designed. This law enable better robustness of the flight control system and tracking control performances. The closed-loop system's stability is guaranteed by the Popov hyperstability theory. The simulation results demonstrate that a better dynamic performance of the UAV flight control system with faults and parametric uncertainties can be maintained with the proposed method.

  5. Adaptive Controller Design for Faulty UAVs via Quantum Information Technology

    Directory of Open Access Journals (Sweden)

    Fuyang Chen

    2012-12-01

    Full Text Available In this paper, an adaptive controller is designed for a UAV flight control system against faults and parametric uncertainties based on quantum information technology and the Popov hyperstability theory. First, considering the bounded control input, the state feedback controller is designed to make the system stable. The model of adaptive control is introduced to eliminate the impact by the uncertainties of system parameters via quantum information technology. Then, according to the model reference adaptive principle, an adaptive control law based on the Popov hyperstability theory is designed. This law enable better robustness of the flight control system and tracking control performances. The closed‐loop system’s stability is guaranteed by the Popov hyperstability theory. The simulation results demonstrate that a better dynamic performance of the UAV flight control system with faults and parametric uncertainties can be maintained with the proposed method.

  6. Generalized ESO and Predictive Control Based Robust Autopilot Design

    Directory of Open Access Journals (Sweden)

    Bhavnesh Panchal

    2016-01-01

    Full Text Available A novel continuous time predictive control and generalized extended state observer (GESO based acceleration tracking pitch autopilot design is proposed for a tail controlled, skid-to-turn tactical missile. As the dynamics of missile are significantly uncertain with mismatched uncertainty, GESO is employed to estimate the state and uncertainty in an integrated manner. The estimates are used to meet the requirement of state and to robustify the output tracking predictive controller designed for nominal system. Closed loop stability for the controller-observer structure is established. An important feature of the proposed design is that it does not require any specific information about the uncertainty. Also the predictive control design yields the feedback control gain and disturbance compensation gain simultaneously. Effectiveness of GESO in estimation of the states and uncertainties and in robustifying the predictive controller in the presence of parametric uncertainties, external disturbances, unmodeled dynamics, and measurement noise is illustrated by simulation.

  7. Microgrid Plant Control Design and Development

    Energy Technology Data Exchange (ETDEWEB)

    Wiegman, Herman; Baone, Chaitanya

    2017-08-14

    This report discusses the technical performance of the proposed microgrid at Potsdam, New York, and the enhanced microgrid controller platform. The test objectives were outlined by the DOE, and summary results and discussion are given for each objective. The findings show that the proposed Potsdam, NY microgrid would have a significant impact on the regional CO2 emissions, the amount of imported energy from the utility, and the resiliency of the critical loads. Additionally, the enhanced microgrid control system developed for this project was tested to be compliant with IEEE 1547 standards, and able to generate revenues to help offset energy costs by way of participation in ancillary services.

  8. Iloprost inhibits fracture repair in rats.

    Science.gov (United States)

    Doğan, Ali; Duygun, Fatih; Kalender, A Murat; Bayram, Irfan; Sungur, Ibrahim

    2014-01-01

    Previous studies have shown that prostaglandins (PGs) dramatically stimulate healing processes in bone. However, the effect of prostaglandin I2 (PGI2) on fracture healing remains unclear. To investigate the effect of PGI2, a study on fracture healing process in closed tibia fractures was designed. Thirty-six Sprague-Dawley male rats were randomized into two groups. On the first day, their right tibias were fractured by three-point bending technique. The study group (n = 18) received a single injection of 10 µg/kg iloprost for 5 days, while the control group (n = 18) received saline solution in the same way. On the 7th, 14th and 28th days following the fracture, six rats were sacrificed and their right legs were harvested in each group. The progression of fracture healing was assessed for each specimen by the scores of radiography (by Lane-Sandhu) and histology (by Huo et al). On the 7th day, the radiographic and histologic scores were equal. On the 14th day radiographic total score was 6 and histologic total score was 23 in the iloprost group, whereas radiographic total score was 11 and histologic total score was 33 in the control group. On the 14th day radiographic and histologic scores were significantly decreased in the iloprost group compared to the control group (P iloprost group, whereas radiographic total score was 15 and histologic total score was 40 in the control group. On the 28th day although there was a decrease in radiographic and histologic scores of the iloprost group acording to control group, it was not statistically significant (P > 0.05). Iloprost delays fracture healing in early stage in rats.

  9. Iloprost inhibits fracture repair in rats

    Institute of Scientific and Technical Information of China (English)

    Ali Do(g)an; Fatih Duygun; A.Murat Kalender; Irfan Bayram; Ibrahim Sungur

    2014-01-01

    Background Previous studies have shown that prostaglandins (PGs) dramatically stimulate healing processes in bone.However,the effect of prostaglandin l2 (PGI2) on fracture healing remains unclear.To investigate the effect of PGI2,a study on fracture healing process in closed tibia fractures was designed.Methods Thirty-six Sprague-Dawley male rats were randomized into two groups.On the first day,their right tibias were fractured by three-point bending technique.The study group (n=18) received a single injection of 10 μg/kg iloprost for 5 days,while the control group (n=18) received saline solution in the same way.On the 7th,14th and 28th days following the fracture,six rats were sacrificed and their right legs were harvested in each group.The progression of fracture healing was assessed for each specimen by the scores of radiography (by Lane-Sandhu) and histology (by Huo et al).Results On the 7th day,the radiographic and histologic scores were equal.On the 14th day radiographic total score was 6 and histologic total score was 23 in the iloprost group,whereas radiographic total score was 11 and histologic total score was 33 in the control group.On the 14th day radiographic and histologic scores were significantly decreased in the iloprost group compared to the control group (P <0.05).On the 28th day radiographic total score was 12 and histologic total score was 37 in the iloprost group,whereas radiographic total score was 15 and histologic total score was 40 in the control group.On the 28th day although there was a decrease in radiographic and histologic scores of the iloprost group acording to control group,it was not statistically significant (P >0.05).Conclusion Iloprost delays fracture healing in early stage in rats.

  10. Fixed-Order Mixed Norm Designs for Building Vibration Control

    Science.gov (United States)

    Whorton, Mark S.; Calise, Anthony J.

    2000-01-01

    This study investigates the use of H2, mu-synthesis, and mixed H2/mu methods to construct full order controllers and optimized controllers of fixed dimensions. The benchmark problem definition is first extended to include uncertainty within the controller bandwidth in the form of parametric uncertainty representative of uncertainty in the natural frequencies of the design model. The sensitivity of H2 design to unmodeled dynamics and parametric uncertainty is evaluated for a range of controller levels of authority. Next, mu-synthesis methods are applied to design full order compensators that are robust to both unmodeled dynamics and to parametric uncertainty. Finally, a set of mixed H2/mu compensators are designed which are optimized for a fixed compensator dimension. These mixed norm designs recover the H2 design performance levels while providing the same levels of robust stability as the mu designs. It is shown that designing with the mixed norm approach permits higher levels of controller authority for which the H2 designs are destabilizing. The benchmark problem is that of an active tendon system. The controller designs are all based on the use of acceleration feedback.

  11. Low-density lipoprotein cholesterol is associated with fracture risk in diabetes patients - a nested case-control study

    DEFF Research Database (Denmark)

    Starup-Linde, Jakob; Gregersen, Søren; Vestergaard, Peter

    2014-01-01

    available for an analysis of patient characteristics, co-morbidities, biochemical parameters and drug usage. Results: Patient age at the time of diabetes diagnosis, a diagnosis of previous fracture, an alcohol related diagnosis, total cholesterol level, and the usage of antidepressants, antiepileptics...... and insulin all increased the odds of fracture. Low-density lipoprotein cholesterol (LDL) levels decreased the odds of fracture, where the level of 3.04-5.96 mmol/l was optimal with regard to fracture risk. Conclusion: LDL may add to the understanding of fractures in diabetes patients and it may be added...

  12. Design and Analysis of Morpheus Lander Flight Control System

    Science.gov (United States)

    Jang, Jiann-Woei; Yang, Lee; Fritz, Mathew; Nguyen, Louis H.; Johnson, Wyatt R.; Hart, Jeremy J.

    2014-01-01

    The Morpheus Lander is a vertical takeoff and landing test bed vehicle developed to demonstrate the system performance of the Guidance, Navigation and Control (GN&C) system capability for the integrated autonomous landing and hazard avoidance system hardware and software. The Morpheus flight control system design must be robust to various mission profiles. This paper presents a design methodology for employing numerical optimization to develop the Morpheus flight control system. The design objectives include attitude tracking accuracy and robust stability with respect to rigid body dynamics and propellant slosh. Under the assumption that the Morpheus time-varying dynamics and control system can be frozen over a short period of time, the flight controllers are designed to stabilize all selected frozen-time control systems in the presence of parametric uncertainty. Both control gains in the inner attitude control loop and guidance gains in the outer position control loop are designed to maximize the vehicle performance while ensuring robustness. The flight control system designs provided herein have been demonstrated to provide stable control systems in both Draper Ares Stability Analysis Tool (ASAT) and the NASA/JSC Trick-based Morpheus time domain simulation.

  13. Design and analysis of tracer tests to determine effective porosity and dispersivity in fractured sedimentary rocks, Newark Basin, New Jersey

    Energy Technology Data Exchange (ETDEWEB)

    Carleton, G.B.; Welty, C.; Buxton, H.T.

    1999-11-01

    Investigations of the transport and fate of contaminants in fractured-rock aquifers require knowledge of aquifer hydraulic and transport characteristics to improve prediction of the rate and direction of movement of contaminated ground water. This report describes an approach to estimating hydraulic and transport properties in fractured-rock aquifers; demonstrates the approach at a sedimentary fractured-rock site in the Newark Basin, N.J.; and provides values for hydraulic and transport properties at the site. The approach has three components: (1) characterization of the hydrogeologic framework of ground-water flow within the rock-fracture network, (2) estimation of the distribution of hydraulic properties (hydraulic conductivity and storage coefficient) within that framework, and (3) estimation of transport properties (effective porosity and dispersivity). The approach includes alternatives with increasingly complex data-collection and analysis techniques.

  14. Design and analysis of tracer tests to determine effective porosity and dispersivity in fractured sedimentary rocks, Newark Basin, New Jersey

    Energy Technology Data Exchange (ETDEWEB)

    Carleton, G.B.; Welty, C.; Buxton, H.T.

    1999-01-01

    Investigations of the transport and fate of contaminants in fractured-rock aquifers require knowledge of aquifer hydraulic and transport characteristics to improve prediction of the rate and direction of movement of contaminated ground water. This report describes an approach to estimating hydraulic and transport properties in fractured-rock aquifers; demonstrates the approach at a sedimentary fractured-rock site in the Newark Basin, N.J.; and provides values for hydraulic and transport properties at the site. The approach has three components: (1) characterization of the hydrogeologic framework of ground-water flow within the rock-fracture network, (2) estimation of the distribution of hydraulic properties (hydraulic conductivity and storage coefficient) within that framework, and (3) estimation of transport properties (effective porosity and dispersivity). The approach includes alternatives with increasingly complex data-collection and analysis techniques.

  15. Passivity Motivated Controller Design for Flexible Structures

    Science.gov (United States)

    1993-01-18

    theoretical approach to the control of systems containing lumped joint flexibility is based on the exact linearization method. for a summary see [4...feedforward compensation (for the exact linearization ) and the feedback stabilization are intertwined and errors in the feedforward may affect the closed loop

  16. Hydraulic Control Design and Modeling Techniques.

    Science.gov (United States)

    1989-02-01

    methodologies. This report may be difficult to read for the casual reader . It is written assuming the reader has some fundamental background in control...INTERVAL DTSMP=.O0012207 STEP=. 0012207 INDEX=INDEX+i DOUT( INDEX2)=L1 A- 4 END $*OF DISCRETE SAMP 2" DERIVATIVE tarot (INDEX2 .GE. 4098) END $*OF

  17. An ellipsoid algorithm for probabilistic robust controller design

    NARCIS (Netherlands)

    Kanev, S.K.; de Schutter, B.; Verhaegen, M.H.G.

    2003-01-01

    In this paper, a new iterative approach to probabilistic robust controller design is presented, which is applicable to any robust controller/filter design problem that can be represented as an LMI feasibility problem. Recently, a probabilistic Subgradient Iteration algorithm was proposed for solving

  18. Design and control considerations for industrial and space manipulators

    Science.gov (United States)

    Whitney, D. E.; Book, W. J.; Lynch, P. M.

    1974-01-01

    This paper is a progress report summarizing theoretical and practical results concerning integration of design and control aspects of manipulator arms for industrial or space applications. The relationships between task specifications, gross motions, fine motions, actuator type and location, size and strength of structural members, control servos and strategies, and overall design evaluation are briefly discussed, with some technical examples.

  19. Estimated Frequency Domain Model Uncertainties used in Robust Controller Design

    DEFF Research Database (Denmark)

    Tøffner-Clausen, S.; Andersen, Palle; Stoustrup, Jakob;

    1994-01-01

    This paper deals with the combination of system identification and robust controller design. Recent results on estimation of frequency domain model uncertainty are......This paper deals with the combination of system identification and robust controller design. Recent results on estimation of frequency domain model uncertainty are...

  20. Analysis and Design Methods for Nonlinear Control Systems

    Science.gov (United States)

    1990-03-01

    entitled "Design of Nonlinear PID Controllers ." In this paper it is demonstrated that the extended linearization approach can be applied to standard...Sciences and Systems, Baltimore, Maryland, pp. 675-680, 1987. [3] WJ. Rugh, "Design of Nonlinear PID Controllers ," AIChE Journa Vol. 33, No. 10, pp. 1738

  1. Design and control considerations for industrial and space manipulators

    Science.gov (United States)

    Whitney, D. E.; Book, W. J.; Lynch, P. M.

    1974-01-01

    This paper is a progress report summarizing theoretical and practical results concerning integration of design and control aspects of manipulator arms for industrial or space applications. The relationships between task specifications, gross motions, fine motions, actuator type and location, size and strength of structural members, control servos and strategies, and overall design evaluation are briefly discussed, with some technical examples.

  2. Fracture Toughness and Thermal Shock Properties of Calcium Aluminate Composite with Controlled Duplex Structure

    Institute of Scientific and Technical Information of China (English)

    W.J.Wei; H.J.Liaw

    2004-01-01

    This study used monocalcium aluminate (CaAl2O4,CA) for producing ceramic composites with duplex microstructures by hydration and gelation reactions of the aluminate, and compared the properties with those made by a die-pressing process of mixed powders. Densification of the composite was optimized. The microstructure of sintered bodies, the fracture strengths and toughness of the composites with and without thermal shocking was characterized by different techniques. Experimental results show that the green body with the addition of CA resulted glomerated platelets or uniform distribution of platy CA6 grains. The former, which appeared a duplex microstructure consisted of dense matrix and distributed clusters of CA6 platelets, performed an improvement on toughness and thermal shock resistance. Toughness mechanisms of samples with duplex microstructure are also investigated.

  3. Guidance on Design of Internet-based Process Control Systems

    Institute of Scientific and Technical Information of China (English)

    S.H.YANG; L.YANG

    2005-01-01

    Internet-based process control is becoming new generations of control systems, in which the Internet is used as a platform for global remote monitoring and control. The obvious benefit is to enable global collaboration between operators from geographically dispersed locations, data sharing and data provision for remote monitoring and control. However, connection to an open network and the use of universal technology present new problems that did not exist with the conventional design and construction of control systems, such as time delay and data loss in Internet transmission and security. This paper reviews the latest research results and presents design guidance of Internet based monitoring and control systems.

  4. INNOVATIVE METHODOLOGY FOR DETECTION OF FRACTURE-CONTROLLED SWEET SPOTS IN THE NORTHERN APPALACHIAN BASIN

    Energy Technology Data Exchange (ETDEWEB)

    Robert Jacobi; John Fountain

    2004-07-08

    The primary goal was to enter Phase 2 by analyzing geophysical logs and sidewall cores from a verification well drilled into the Trenton/Black River section along lineaments. However, the well has not yet been drilled; Phase 2 has therefore not been accomplished. Secondary goals in Phase I were also completed for the last reporting period. Thus, no new data were collected for this reporting period, and only soil gas surveys were reanalyzed and re-displayed in the region of the Trenton/Black River wells. The soil gas profiles in the region of the Trenton/Black River wells show that individual large-magnitude soil gas anomalies (spikes) are rarely wider than 50 m. Even clusters of soil gas spikes are only on the order of 200-250 m wide. Thus, widely-spaced sampling will not necessarily represent the actual number and location of soil gas seeps. The narrowness of the anomalies suggests that the seeps result from single fractures or narrow fracture intensification domains (FIDs). Many of the lineaments from EarthSat (1997) and straight stream segments coincide (or are very close to) soil gas spikes, but we collected many more soil gas spikes than lineaments. Among some of the soil gas box surveys, a possible ENE-trend of spikes can be discerned. This ENE-striking trend is, however, about 10{sup o} away from a nearby Earthsat (1997) trend. These data continue to demonstrate that integration of aeromagnetic and remote sensing lineaments, surface structure, soil gas and seismic allows us to extrapolate Trenton-Black River trends away from confirmatory seismic lines.

  5. The Application of Layer Theory to Design: The Control Layer

    Science.gov (United States)

    Gibbons, Andrew S.; Langton, Matthew B.

    2016-01-01

    A theory of design layers proposed by Gibbons ("An Architectural Approach to Instructional Design." Routledge, New York, 2014) asserts that each layer of an instructional design is related to a body of theory closely associated with the concerns of that particular layer. This study focuses on one layer, the control layer, examining…

  6. Integrated Process Design and Control of Reactive Distillation Processes

    DEFF Research Database (Denmark)

    Mansouri, Seyed Soheil; Sales-Cruz, Mauricio; Huusom, Jakob Kjøbsted

    2015-01-01

    In this work, integrated design and control of reactive distillation processes is presented. Simple graphical design methods that are similar in concept to non-reactive distillation processes are used, such as reactive McCabe-Thiele method and driving force approach. The methods are based...... of this approach, it is shown that designing the reactive distillation process at the maximum driving force results in an optimal design in terms of controllability and operability. It is verified that the reactive distillation design option is less sensitive to the disturbances in the feed at the highest driving...

  7. On PID Controller Design Using Knowledge Based Fuzzy System

    Directory of Open Access Journals (Sweden)

    Jana Nowakova

    2012-01-01

    Full Text Available The designing of PID controllers is a frequently discussed problem. Many of design methods have been developed, classic (analytical tuning methods, optimization methods etc. or not so common fuzzy knowledge based methods which are designed to achieve good setpoint following, corresponding time response etc. In this case, the new way of designing PID controller parameters is created where the above mentioned knowledge system based on relations of Ziegler-Nichols design methods is used, more precisely the combination of the both Ziegler-Nichols methods. The proof of efficiency of a proposed method and a numerical experiment is presented.

  8. Production Quality Control Of Microfluidic Chip Designs

    DEFF Research Database (Denmark)

    Calaon, Matteo; Hansen, Hans Nørgaard; Tosello, Guido

    2012-01-01

    -beam lithography. Subsequent nickel electroplating was employed to replicate the obtained geometries on the tool, which was used to mold on transparent polymer substrates the functional structures. To assess the critical factors affecting the replication quality throughout the different steps of the proposed...... process chain, test geometries were designed and produced on the side of the functional features. The so called “Finger Print” of the lithography and molding processes was qualitatively and quantitatively evaluated through scanning electron microscopy and atomic force microscopy respectively. The entire...

  9. Haystack Antenna Control System Design Document

    Science.gov (United States)

    2010-12-07

    Interface C ontrol D ocuments (ICDs). T hese ICDs w ill d efine t he d ata t hat i s transferred b etween t he r adar or a stronomy computer a nd t he a...ea ch ax is d efined f or t he p edestal ( as h eld i n t he pedestalDefinition s tructure w ithin th e P edestal O bject). The axis obj ect e...Note t hat t he co mpensators are d efined b y s trings. Compensator design is discussed in paragraph. //Azimuth axis definition [AXIS 0 DEFINITION

  10. Characterising rock fracture aperture-spacing relationships using power-law relationships: some considerations

    Science.gov (United States)

    Brook, Martin; Hebblewhite, Bruce; Mitra, Rudrajit

    2016-04-01

    The size-scaling of rock fractures is a well-studied problem in geology, especially for permeability quantification. The intensity of fractures may control the economic exploitation of fractured reservoirs because fracture intensity describes the abundance of fractures potentially available for fluid flow. Moreover, in geotechnical engineering, fractures are important for parameterisation of stress models and excavation design. As fracture data is often collected from widely-spaced boreholes where core recovery is often incomplete, accurate interpretation and representation of fracture aperture-frequency relationships from sparse datasets is important. Fracture intensity is the number of fractures encountered per unit length along a sample scanline oriented perpendicular to the fractures in a set. Cumulative frequency of fractures (F) is commonly related to fracture aperture (A) in the form of a power-law (F = aA-b), with variations in the size of the a coefficient between sites interpreted to equate to fracture frequency for a given aperture (A). However, a common flaw in this approach is that even a small change in b can have a large effect on the response of the fracture frequency (F) parameter. We compare fracture data from the Late Permian Rangal Coal Measures from Australia's Bowen Basin, with fracture data from Jurassic carbonates from the Sierra Madre Oriental, northeastern Mexico. Both power-law coefficient a and exponent b control the fracture aperture-frequency relationship in conjunction with each other; that is, power-laws with relatively low a coefficients have relatively high b exponents and vice versa. Hence, any comparison of different power-laws must take both a and b into consideration. The corollary is that different sedimentary beds in the Sierra Madre carbonates do not show ˜8× the fracture frequency for a given fracture aperture, as based solely on the comparison of coefficient a. Rather, power-law "sensitivity factors" developed from both

  11. Design of a Helicopter Stability and Control Augmentation System Using Optimal Control Theory.

    Science.gov (United States)

    technique is described for the design of multivariable feedback controllers based upon results in optimal control theory . For a specified performance...helicopter flight envelope. The results show that optimal control theory can be used to design a helicopter stability and control augmentation system

  12. Sliding Mode Control Design via Reduced Order Model Approach

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper presents a design of continuous-time sliding mode control for the higher order systems via reduced order model. It is shown that a continuous-time sliding mode control designed for the reduced order model gives similar performance for the higher order system. The method is illustrated by numerical examples. The paper also introduces a technique for design of a sliding surface such that the system satisfies a cost-optimality condition when on the sliding surface.

  13. Design and Control of a Powered Transfemoral Prosthesis

    OpenAIRE

    Sup, Frank; Bohara, Amit; Goldfarb, Michael

    2008-01-01

    The paper describes the design and control of a transfemoral prosthesis with powered knee and ankle joints. The initial prototype is a pneumatically actuated powered-tethered device, which is intended to serve as a laboratory test bed for a subsequent self-powered version. The prosthesis design is described, including its kinematic optimization and the design of a three-axis socket load cell that measures the forces and moments of interaction between the socket and prosthesis. A gait controll...

  14. Buck-boost converter feedback controller design via evolutionary search

    Science.gov (United States)

    Sundareswaran, K.; Devi, V.; Nadeem, S. K.; Sreedevi, V. T.; Palani, S.

    2010-11-01

    Buck-boost converters are switched power converters. The model of the converter system varies from the ON state to the OFF state and hence traditional methods of controller design based on approximate transfer function models do not yield good dynamic response at different operating points of the converter system. This article attempts to design a feedback controller for a buck-boost type dc-dc converter using a genetic algorithm. The feedback controller design is perceived as an optimisation problem and a robust controller is estimated through an evolutionary search. Extensive simulation and experimental results provided in the article show the effectiveness of the new approach.

  15. Should we attempt global (inlet engine airframe) control design?

    Science.gov (United States)

    Carlin, C. M.

    1980-01-01

    The feasibility of multivariable design of the entire airplane control system is briefly addressed. An intermediate step in that direction is to design a control for an inlet engine augmentor system by using multivariable techniques. The supersonic cruise large scale inlet research program is described which will provide an opportunity to develop, integrate, and wind tunnel test a control for a mixed compression inlet and variable cycle engine. The integrated propulsion airframe control program is also discussed which will introduce the problem of implementing MVC within a distributed processing avionics architecture, requiring real time decomposition of the global design into independent modules in response to hardware communication failures.

  16. Control Variates and Optimal Designs in Metamodeling

    Science.gov (United States)

    2013-03-01

    and a series of tasks. Henderson and Kim (2004) apply CVs to a discrete time-finite state space markov chain . Adewunmi and Aickelin (2012) describe...going into further detail with an example in machine repair, an inventory system, and an M/M/1 queue . Fort and Moulines (2008) apply CVs to financial...are not always effective. Because of the long queue length these control variates are ineffective, additional iterations of the model will show that

  17. Designing a sustainable strategy for malaria control?

    Directory of Open Access Journals (Sweden)

    Mharakurwa Sungano

    2011-08-01

    Full Text Available Abstract Malaria in the 21st century is showing signs of declining over much of its distribution, including several countries in Africa where previously this was not thought to be feasible. Yet for the most part the strategies to attack the infection are similar to those of the 1950s. Three major Journals have recently drawn attention to the situation, stressing the importance of research, describing the successes and defining semantics related to control. But there is a need to stress the importance of local sustainability, and consider somewhat urgently how individual endemic countries can plan and implement the programmes that are currently financed, for the most part, by donor institutions. On an immediate basis research should be more focused on a data driven approach to control. This will entail new thinking on the role of local infrastructure and in training of local scientists in local universities in epidemiology and field malariology so that expanded control programmes can become operational. Donor agencies should encourage and facilitate development of career opportunities for such personnel so that local expertise is available to contribute appropriately.

  18. Control system design for flexible structures using data models

    Science.gov (United States)

    Irwin, R. Dennis; Frazier, W. Garth; Mitchell, Jerrel R.; Medina, Enrique A.; Bukley, Angelia P.

    1993-01-01

    The dynamics and control of flexible aerospace structures exercises many of the engineering disciplines. In recent years there has been considerable research in the developing and tailoring of control system design techniques for these structures. This problem involves designing a control system for a multi-input, multi-output (MIMO) system that satisfies various performance criteria, such as vibration suppression, disturbance and noise rejection, attitude control and slewing control. Considerable progress has been made and demonstrated in control system design techniques for these structures. The key to designing control systems for these structures that meet stringent performance requirements is an accurate model. It has become apparent that theoretically and finite-element generated models do not provide the needed accuracy; almost all successful demonstrations of control system design techniques have involved using test results for fine-tuning a model or for extracting a model using system ID techniques. This paper describes past and ongoing efforts at Ohio University and NASA MSFC to design controllers using 'data models.' The basic philosophy of this approach is to start with a stabilizing controller and frequency response data that describes the plant; then, iteratively vary the free parameters of the controller so that performance measures become closer to satisfying design specifications. The frequency response data can be either experimentally derived or analytically derived. One 'design-with-data' algorithm presented in this paper is called the Compensator Improvement Program (CIP). The current CIP designs controllers for MIMO systems so that classical gain, phase, and attenuation margins are achieved. The center-piece of the CIP algorithm is the constraint improvement technique which is used to calculate a parameter change vector that guarantees an improvement in all unsatisfied, feasible performance metrics from iteration to iteration. The paper also

  19. Reduction of Network Effects On Control System Performance by Controller Design

    Directory of Open Access Journals (Sweden)

    Naser Pariz

    2007-09-01

    Full Text Available This paper discusses the impact of network architecture on control performance in a class of distributed control systems called Networked Control Systems (NCSs and provides design considerations related to control quality.Then, we discuss the framework for controller design NCSs where sensors, actuators, and controllers are distributed and interconnected by a common communication network. Multiple distributed communication delays as well as multiple inputs and multiple outputs are considered in the discretetime modeling algorithm. The proposed NCS model is used as a foundation for optimal controller design to compensate for the multiple time delays. The proposed control algorithm utilizes the information of delayed signals and improves the control performance of a control system with distributed communication delays. Several simulation studies are provided to evaluate the control performance of the proposed controller design.

  20. Nonoperative Treatment of Thoracic and Lumbar Spine Fractures : A Prospective Randomized Study of Different Treatment Options

    NARCIS (Netherlands)

    Stadhouder, Agnita; Buskens, Erik; Vergroesen, Diederik A.; Fidler, Malcolm W.; de Nies, Frank; Oner, F. C.

    Objectives: To evaluate and compare nonoperative treatment methods for traumatic thoracic and lumbar compression fractures and burst fractures. Design: Prospective randomized controlled trial with long-term follow-up. Setting: Two general hospitals in the Netherlands. Patients/Participants: Patients

  1. Review on design and control aspects of ankle rehabilitation robots.

    Science.gov (United States)

    Jamwal, Prashant K; Hussain, Shahid; Xie, Sheng Q

    2015-03-01

    Ankle rehabilitation robots can play an important role in improving outcomes of the rehabilitation treatment by assisting therapists and patients in number of ways. Consequently, few robot designs have been proposed by researchers which fall under either of the two categories, namely, wearable robots or platform-based robots. This paper presents a review of both kinds of ankle robots along with a brief analysis of their design, actuation and control approaches. While reviewing these designs it was observed that most of them are undesirably inspired by industrial robot designs. Taking note of the design concerns of current ankle robots, few improvements in the ankle robot designs have also been suggested. Conventional position control or force control approaches, being used in the existing ankle robots, have been reviewed. Apparently, opportunities of improvement also exist in the actuation as well as control of ankle robots. Subsequently, a discussion on most recent research in the development of novel actuators and advanced controllers based on appropriate physical and cognitive human-robot interaction has also been included in this review. Implications for Rehabilitation Ankle joint functions are restricted/impaired as a consequence of stroke or injury during sports or otherwise. Robots can help in reinstating functions faster and can also work as tool for recording rehabilitation data useful for further analysis. Evolution of ankle robots with respect to their design and control aspects has been discussed in the present paper and a novel design with futuristic control approach has been proposed.

  2. Orthopaedic resident preparedness for closed reduction and pinning of pediatric supracondylar fractures is improved by e-learning: a multisite randomized controlled study.

    Science.gov (United States)

    Hearty, Thomas; Maizels, Max; Pring, Maya; Mazur, John; Liu, Raymond; Sarwark, John; Janicki, Joseph

    2013-09-04

    There is a need to provide more efficient surgical training methods for orthopaedic residents. E-learning could possibly increase resident surgical preparedness, confidence, and comfort for surgery. Using closed reduction and pinning of pediatric supracondylar humeral fractures as the index case, we hypothesized that e-learning could increase resident knowledge acquisition for case preparation in the operating room. An e-learning surgical training module was created on the Computer Enhanced Visual Learning platform. The module provides a detailed and focused road map of the procedure utilizing a multimedia format. A multisite prospective randomized controlled study design compared residents who used a textbook for case preparation (control group) with residents who used the same textbook plus completed the e-learning module (test group). All subjects completed a sixty-question test on the theory and methods of the case. After completion of the test, the control group then completed the module as well. All subjects were surveyed on their opinion regarding the effectiveness of the module after performing an actual surgical case. Twenty-eight subjects with no previous experience in this surgery were enrolled at four academic centers. Subjects were randomized into two equal groups. The test group scored significantly better (p < 0.001) and demonstrated competence on the test compared with the control group; the mean correct test score (and standard deviation) was 90.9% ± 6.8% for the test group and 73.5% ± 6.4% for the control group. All residents surveyed (n = 27) agreed that the module is a useful supplement to traditional methods for case preparation and twenty-two of twenty-seven residents agreed that it reduced their anxiety during the case and improved their attention to surgical detail. E-learning using the Computer Enhanced Visual Learning platform significantly improved preparedness, confidence, and comfort with percutaneous closed reduction and pinning of a

  3. Higher fish intake is associated with a lower risk of hip fractures in Chinese men and women: a matched case-control study.

    Directory of Open Access Journals (Sweden)

    Fan Fan

    Full Text Available OBJECTIVES: Fish is rich in nutrients that are favorable to bone health, but limited data are available regarding the relationship between fish intake and hip fractures. Our study examined the association between habitual fish intake and risk of hip fractures. METHODS: A case-control study was performed between June 2009 and June 2012 in Guangdong Province, China. Five hundred and eighty-one hip fracture incident cases, aged 55 to 80 years (mean: 71 years, were enrolled from four hospitals. 1∶1 matched controls by gender and age (±3 years were also recruited from communities and hospitals. Face-to-face interviews were used to obtain habitual dietary intake and information on various covariates. RESULTS: Univariate conditional logistic regression analyses showed significantly dose-dependent inverse correlations between the risk of hip fractures and the intake of fresh-water fish, sea fish, mollusca, shellfish, and total fish in all of the subjects (p-trend: <0.001-0.016. After adjusting for covariates, the associations were slightly attenuated but remained significant for all (p-trend: <0.001-0.017 except for fresh-water fish (p = 0.553. The ORs (95%CI of hip fractures for the highest (vs. lowest quartile were 0.80 (0.48-1.31 for fresh-water fish, 0.31 (0.18-0.52 for sea fish, 0.55 (0.34-0.88 for mollusca and shellfish, and 0.47 (0.28-0.79 for total fish, respectively. Stratified and interaction analyses showed that the association was more significant in males than in females (p-interaction = 0.052. CONCLUSION: Higher intake of seafood is independently associated with lower risk of hip fractures in elderly Chinese. Increasing consumption of sea fish may benefit the prevention of hip fractures in this population.

  4. Robust control for snake maneuver design of missile

    Science.gov (United States)

    Kun, Ya; Chen, Xin; Li, Chuntao

    2017-01-01

    For the performance of missile with high Mach number and strongly nonlinear dynamics, this paper uses robust control to design maneuver controller. Robust servomechanism linear quadratic regulator (RSLQR) control is used to form the inner loop and proportional-plus-integral (PI) control is used to provide yawing tracking with no error. Contrast simulations under three types of deviation have been done to confirm robustness of the RSLQR-plus-PI control. Simulation results shows that RSLQR-plus-PI control would resist the disturbance and maintain the properties of the controller, guarantee the robustness and stability of missile more effectively than pure PI control.

  5. [Atlas fractures].

    Science.gov (United States)

    Schären, S; Jeanneret, B

    1999-05-01

    Fractures of the atlas account for 1-2% of all vertebral fractures. We divide atlas fractures into 5 groups: isolated fractures of the anterior arch of the atlas, isolated fractures of the posterior arch, combined fractures of the anterior and posterior arch (so-called Jefferson fractures), isolated fractures of the lateral mass and fractures of the transverse process. Isolated fractures of the anterior or posterior arch are benign and are treated conservatively with a soft collar until the neck pain has disappeared. Jefferson fractures are divided into stable and unstable fracture depending on the integrity of the transverse ligament. Stable Jefferson fractures are treated conservatively with good outcome while unstable Jefferson fractures are probably best treated operatively with a posterior atlanto-axial or occipito-axial stabilization and fusion. The authors preferred treatment modality is the immediate open reduction of the dislocated lateral masses combined with a stabilization in the reduced position using a transarticular screw fixation C1/C2 according to Magerl. This has the advantage of saving the atlanto-occipital joints and offering an immediate stability which makes immobilization in an halo or Minerva cast superfluous. In late instabilities C1/2 with incongruency of the lateral masses occurring after primary conservative treatment, an occipito-cervical fusion is indicated. Isolated fractures of the lateral masses are very rare and may, if the lateral mass is totally destroyed, be a reason for an occipito-cervical fusion. Fractures of the transverse processes may be the cause for a thrombosis of the vertebral artery. No treatment is necessary for the fracture itself.

  6. Robust Control Design for Uncertain Nonlinear Dynamic Systems

    Science.gov (United States)

    Kenny, Sean P.; Crespo, Luis G.; Andrews, Lindsey; Giesy, Daniel P.

    2012-01-01

    Robustness to parametric uncertainty is fundamental to successful control system design and as such it has been at the core of many design methods developed over the decades. Despite its prominence, most of the work on robust control design has focused on linear models and uncertainties that are non-probabilistic in nature. Recently, researchers have acknowledged this disparity and have been developing theory to address a broader class of uncertainties. This paper presents an experimental application of robust control design for a hybrid class of probabilistic and non-probabilistic parametric uncertainties. The experimental apparatus is based upon the classic inverted pendulum on a cart. The physical uncertainty is realized by a known additional lumped mass at an unknown location on the pendulum. This unknown location has the effect of substantially altering the nominal frequency and controllability of the nonlinear system, and in the limit has the capability to make the system neutrally stable and uncontrollable. Another uncertainty to be considered is a direct current motor parameter. The control design objective is to design a controller that satisfies stability, tracking error, control power, and transient behavior requirements for the largest range of parametric uncertainties. This paper presents an overview of the theory behind the robust control design methodology and the experimental results.

  7. Ketamine Infusion Therapy as an Alternative Pain Control Strategy in Patients with Multi-Trauma including Rib Fracture; Case Report and Literature Review.

    Science.gov (United States)

    Losing, Ashley K; Jones, Justin M; Keric, Adis; Briggs, Steven E; Leedahl, David D

    2016-07-01

    Ketamine is a promising alternative agent for pain control that offers benefit to traditional strategies, particularly in the setting of rib fracture. Current pharmacologic therapies have clear adverse effects, and other options may be invasive, cost prohibitive, or marginally effective. We describe three consecutive patients with traumatic injuries including rib fracture for which a ketamine infusion was utilized as part of their pain control strategy.  For each patient, use of a ketamine infusion trended toward reduced opioid requirements with stable pain scores. One patient experienced a dissociative adverse effect prompting decrease and discontinuation of ketamine. No pulmonary complications in the form of emergent intubation or new diagnosis of pneumonia were observed. We believe the addition of ketamine infusion to be a valid alternative strategy for managing pain associated with rib fracture.

  8. Recursive design of nonlinear H _∞ excitation controller

    Institute of Scientific and Technical Information of China (English)

    卢强; 梅生伟; 申铁龙; 胡伟

    2000-01-01

    This work is concerned with the problem of L2 gain disturbance attenuation for nonlinear systems and nonlinear robust control for power systems. In terms of the recurrence design approach proposed, the nonnegative solution of dissipative inequality and the storage function of nonlinear H∞ control for a generator excitation system are acquired. From this storage function, the excitation controller is constructed. Moreover, simulation results manifest the effectiveness of this design method.

  9. Controller Design of High Order Nonholonomic System with Nonlinear Drifts

    Institute of Scientific and Technical Information of China (English)

    Xiu-Yun Zheng; Yu-Qiang Wu

    2009-01-01

    A controller design is proposed for a class of high order nonholonomic systems with nonlinear drifts. The purpose is to ensure a solution for the closed-loop system regulated to zero. Adding a power integrator backstepping technique and the switching control strategy are employed to design the controller. The state scaling is applied to the recursive manipulation. The simulation example demonstrates the effectiveness and robust features of the proposed method.

  10. Production Quality Control Of Microfluidic Chip Designs

    DEFF Research Database (Denmark)

    Calaon, Matteo; Hansen, Hans Nørgaard; Tosello, Guido

    2012-01-01

    process chain, test geometries were designed and produced on the side of the functional features. The so called “Finger Print” of the lithography and molding processes was qualitatively and quantitatively evaluated through scanning electron microscopy and atomic force microscopy respectively. The entire......The challenge of fabricating geometries with critical dimensions ranging from few microns down to 10 nanometers with high production rate is delaying the development of nanotechnology based products. Diverse research works have shown the capability of technologies such as UV lithography, nano...... imprint lithography and e-beam lithography to produce micro and nano features. However, their application for tooling purposes is relatively new and the potential to produce nanometer features with high volume low cost production is enormous. Considering possible implementation in a mass production...

  11. Design of a remote controlled hovercraft

    OpenAIRE

    Álvarez Sánchez, David

    2009-01-01

    Este informe trata el diseño, desarrollo y construcción de un aerodeslizador de pequeño tamaño, equipado con control remoto que permite al usuario actuar sobre la velocidad y dirección del mismo. Este proyecto podrá ser utilizado en un futuro como base para el desarrollo de aplicaciones más complejas. Un aerodeslizador es un medio de transporte cuyo chasis se eleva sobre el suelo por medio de un motor impulsor que hincha una falda colocada en la parte inferior del mismo. Además, uno ...

  12. Control design profits heliostat techno-economics

    CSIR Research Space (South Africa)

    Rubin, N

    2012-05-01

    Full Text Available of nine constant radius arcs, and East-West symmetry in the field. It was under these field layout assumptions that a simulation model was developed at the CSIR in 2011, in order to refine the solar spillage models in HFLCAL. The principal... control; cost-benefit tradeoffs 1. Introduction Roos [1] motivates that the use of heliostat mirrors for solar power concentration, combined with the conversion of thermal to electrical energy via gas turbine, is economically attractive for remote, semi...

  13. Control law design to meet constraints using SYNPAC-synthesis package for active controls

    Science.gov (United States)

    Adams, W. M., Jr.; Tiffany, S. H.

    1982-01-01

    Major features of SYNPAC (Synthesis Package for Active Controls) are described. SYNPAC employs constrained optimization techniques which allow explicit inclusion of design criteria (constraints) in the control law design process. Interrelationships are indicated between this constrained optimization approach, classical and linear quadratic Gaussian design techniques. Results are presented that were obtained by applying SYNPAC to the design of a combined stability augmentation/gust load alleviation control law for the DAST ARW-2.

  14. Thoracic paravertebral block versus intravenous patient-controlled analgesia for pain treatment in patients with multiple rib fractures.

    Science.gov (United States)

    Yeying, Ge; Liyong, Yuan; Yuebo, Chen; Yu, Zhang; Guangao, Ye; Weihu, Ma; Liujun, Zhao

    2017-01-01

    Objectives To assess the effect of thoracic paravertebral block (PVB) on pain management and preservation of pulmonary function compared with intravenous, patient-controlled analgesia (IVPCA) in patients with multiple rib fractures (MRFs). Methods Ninety patients with unilateral MRFs were included in this prospective study and randomly assigned to the TPVB or IVPCA group. The visual analogue scale (VAS) pain score, blood gas analysis, and bedside spirometry were measured and recorded at different time points after analgesia. Results TPVB and IVPCA provided good pain relief. VAS scores were significantly lower in the TPVB group than in the IVPCA group at rest and during coughing ( P pain relief and preservation of pulmonary function in patients with MRFs.

  15. A Control Law Design Method Facilitating Control Power, Robustness, Agility, and Flying Qualities Tradeoffs: CRAFT

    Science.gov (United States)

    Murphy, Patrick C.; Davidson, John B.

    1998-01-01

    A multi-input, multi-output control law design methodology, named "CRAFT", is presented. CRAFT stands for the design objectives addressed, namely, Control power, Robustness, Agility, and Flying Qualities Tradeoffs. The methodology makes use of control law design metrics from each of the four design objective areas. It combines eigenspace assignment, which allows for direct specification of eigenvalues and eigenvectors, with a graphical approach for representing the metrics that captures numerous design goals in one composite illustration. Sensitivity of the metrics to eigenspace choice is clearly displayed, enabling the designer to assess the cost of design tradeoffs. This approach enhances the designer's ability to make informed design tradeoffs and to reach effective final designs. An example of the CRAFT methodology applied to an advanced experimental fighter and discussion of associated design issues are provided.

  16. Improved LTVMPC design for steering control of autonomous vehicle

    Science.gov (United States)

    Velhal, Shridhar; Thomas, Susy

    2017-01-01

    An improved linear time varying model predictive control for steering control of autonomous vehicle running on slippery road is presented. Control strategy is designed such that the vehicle will follow the predefined trajectory with highest possible entry speed. In linear time varying model predictive control, nonlinear vehicle model is successively linearized at each sampling instant. This linear time varying model is used to design MPC which will predict the future horizon. By incorporating predicted input horizon in each successive linearization the effectiveness of controller has been improved. The tracking performance using steering with front wheel and braking at four wheels are presented to illustrate the effectiveness of the proposed method.

  17. Comprehensive Geriatric Assessment for Prevention of Delirium After Hip Fracture: A Systematic Review of Randomized Controlled Trials.

    Science.gov (United States)

    Shields, Lynn; Henderson, Victoria; Caslake, Robert

    2017-07-01

    To assess the efficacy of comprehensive geriatric assessment (CGA) in prevention of delirium after hip fracture. Systematic review and metaanalysis. Ward based models on geriatrics wards and visiting team based models on orthopaedics wards were included. Four trials (three European, one U.S.; 973 participants) were identified. Two assessed ward-based, and two assessed team-based interventions. MEDLINE, EMBASE, CINAHL and PsycINFO databases; Clinicaltrials.gov; and the Central Register of Controlled Trials were searched. Reference lists from full-text articles were reviewed. Incidence of delirium was the primary outcome. Length of stay, delirium severity, institutionalization, long-term cognition and mortality were predefined secondary outcomes. Duration of delirium was included as a post hoc outcome. There was a significant reduction in delirium overall (relative risk (RR) = 0.81, 95% confidence interval (CI) = 0.69-0.94) in the intervention group. Post hoc subgroup analysis found this effect to be preserved in the team-based intervention group (RR = 0.77, 95% CI = 0.61-0.98) but not the ward-based group. No significant effect was observed on any secondary outcome. There was a reduction in the incidence of delirium after hip fracture with CGA. This is in keeping with results of non-randomized controlled trials and trials in other populations. Team-based interventions appeared superior in contrast to the Ellis CGA paper, but it is likely that heterogeneity in interventions and population studied affected this. © 2017, Copyright the Authors Journal compilation © 2017, The American Geriatrics Society.

  18. Chemical optimization algorithm for fuzzy controller design

    CERN Document Server

    Astudillo, Leslie; Castillo, Oscar

    2014-01-01

    In this book, a novel optimization method inspired by a paradigm from nature is introduced. The chemical reactions are used as a paradigm to propose an optimization method that simulates these natural processes. The proposed algorithm is described in detail and then a set of typical complex benchmark functions is used to evaluate the performance of the algorithm. Simulation results show that the proposed optimization algorithm can outperform other methods in a set of benchmark functions. This chemical reaction optimization paradigm is also applied to solve the tracking problem for the dynamic model of a unicycle mobile robot by integrating a kinematic and a torque controller based on fuzzy logic theory. Computer simulations are presented confirming that this optimization paradigm is able to outperform other optimization techniques applied to this particular robot application

  19. CURBSIDE CONSULTATION IN FRACTURE MANAGEMENT: 49 CLINICAL QUESTIONS

    Directory of Open Access Journals (Sweden)

    Walter W. Virkus

    2008-12-01

    Full Text Available DESCRIPTION: A user-friendly, unique resource for the treatment of fractures designed in a casual questions and answers format which provides basic knowledge, current information and evidence based expert advices enhanced by images and diagrams and supported by ref-erences.PURPOSE: Designing this book the editor has aimed to prepare not only a source of current knowledge and opin-ions by experienced authors in fracture management for decision making in daily practice but also a brief refer-ence and useful educational resource in orthopedic trauma surgery.FEATURES: Three Sections are composed of 49 sub-jects in a form of the answers of frequently asked ques-tions richly illustrated by images and diagrams and in-cluding references at the end of each subject.The Section I is “UPPER EXTREMITIES” including: Neck fracture; Humerus shaft fracture; Management of radial nerve palsy associated with humeral fracture; Clavicle fractures; Elbow fractures in children; Fasciot-omy technic of the forearm; Distal radius fracture; Indica-tions of radial head replacement, Femur and humeral shaft fractures; Treatment of posterolateral elbow dislocation; The Section II is “LOWER EXTREMITIES” including : Femur fractures; Pelvic fractures; Life threatening pelvic fractures; Decision for surgical treatment in pelvic frac-tures; Treatment of anterior fracture of femoral head and hip joint incongruity; Management of a displaced femoral neck fracture in young patient in ER; Elder patients with displaced femoral head fracture; Patella and tibial plateau fractures; Criteria for compartment syndromes in the tibia; Tricks in nailing proximal and distal tibial fractures; Surgical management of distal tibia spiral fracture in middle aged women; Pilon fracture; Management of syn-desmotic screws in adult patient; The management of minimally displaced posterior malleol in three malleolar fractures; Postoperative management of bimalleolar frac-tures; Management of minimally

  20. Brushless DC Motor Control System Design Based on DSP2812

    Directory of Open Access Journals (Sweden)

    Wei Min

    2016-01-01

    Full Text Available By comparison various control methods currently for permanent magnet brushless DC motor, on the basis of motor principle analysis, a current smallest and most real-time all-digital rare earth permanent magnet brushless DC motor control system is designed. The high-speed digital signal processor DSP2812 is applied as the main control unit. The fuzzy PID control algorithm is used to control rectifier regulator and speed, which the speed and current is double closed loop in the system. The principle of control system, control strategy and software is analyzed in this paper. The system has some features such as less overshoot, rapid response speed, good performance of anti-jamming, simple structure, high control precision, flexible in changing control policies and so on. Validity of the design is verified by prototype test.

  1. Control vocabulary software designed for CMIP6

    Science.gov (United States)

    Nadeau, D.; Taylor, K. E.; Williams, D. N.; Ames, S.

    2016-12-01

    The Coupled Model Intercomparison Project Phase 6 (CMIP6) coordinates a number of intercomparison activities and includes many more experiments than its predecessor, CMIP5. In order to organize and facilitate use of the complex collection of expected CMIP6 model output, a standard set of descriptive information has been defined, which must be stored along with the data. This standard information enables automated machine interpretation of the contents of all model output files. The standard metadata is stored in compliance with the Climate and Forecast (CF) standard, which ensures that it can be interpreted and visualized by many standard software packages. Additional attributes (not standardized by CF) are required by CMIP6 to enhance identification of models and experiments, and to provide additional information critical for interpreting the model results. To ensure that CMIP6 data complies with the standards, a python program called "PrePARE" (Pre-Publication Attribute Reviewer for the ESGF) has been developed to check the model output prior to its publication and release for analysis. If, for example, a required attribute is missing or incorrect (e.g., not included in the reference CMIP6 controlled vocabularies), then PrePare will prevent publication. In some circumstances, missing attributes can be created or incorrect attributes can be replaced automatically by PrePARE, and the program will warn users about the changes that have been made. PrePARE provides a final check on model output assuring adherence to a baseline conformity across the output from all CMIP6 models which will facilitate analysis by climate scientists. PrePARE is flexible and can be easily modified for use by similar projects that have a well-defined set of metadata and controlled vocabularies.

  2. Mechanical design and control of a new myoelectric hand prosthesis

    NARCIS (Netherlands)

    Peerdeman, B.; Stramigioli, S.; Hekman, E.; Brouwer, D.M.; Misra, S.

    2011-01-01

    The development of modern, myoelectrically controlled hand prostheses can be difficult, due to the many requirements its mechanical design and control system need to fulfill [1]. The hand should be controllable with few input signals, while being able to perform a wide range of motions. It should be

  3. Design of a PID Controller for a PCR Micro Reactor

    Science.gov (United States)

    Dinca, M. P.; Gheorghe, M.; Galvin, P.

    2009-01-01

    Proportional-integral-derivative (PID) controllers are widely used in process control, and consequently they are described in most of the textbooks on automatic control. However, rather than presenting the overall design process, the examples given in such textbooks are intended to illuminate specific focused aspects of selection, tuning and…

  4. Optimal Excitation Controller Design for Wind Turbine Generator

    Directory of Open Access Journals (Sweden)

    A. K. Boglou

    2011-01-01

    Full Text Available An optimal excitation controller design based on multirate-output controllers (MROCs having a multirate sampling mechanismwith different sampling period in each measured output of the system is presented. The proposed H∞ -control techniqueis applied to the discrete linear open-loop system model which represents a wind turbine generator supplying an infinite busthrough a transmission line.

  5. Reduced fracture risk in users of thiazide diuretics.

    Science.gov (United States)

    Rejnmark, L; Vestergaard, P; Mosekilde, L

    2005-03-01

    Thiazide diuretics (TD) reduce renal calcium excretion and may increase bone mineral density. A reduced fracture risk has been reported in some but not all studies. The aim of this study was to assess fracture risk in users of TD. The study design was nationwide population-based pharmacoepidemiological case-control study with fracture in year 2000 as outcome and use of TD during the previous 5 years as the exposure variable. Individual use of TD was derived from the Danish National Pharmacological Database and related to fracture data from the National Hospital Discharge Register. These data were combined with information on use of other drugs, social status, working status, income, educational status, contacts with general practitioners and practicing specialists, and comorbidity. A total of 64,699 patients (age = 40 years) who sustained a fracture during the year 2000 were compared to 194,111 age- and gender-matched controls. After adjustment for potential confounders, current use of TD was associated with a 10% (95% confidence interval [CI], 7% to 12%) reduced risk of any fracture and a 17% (95% CI 11% to 23%) reduced risk of forearm fractures. In former TD users, the risk reduction was slightly less pronounced. Similar results were found in men and women, and in subjects younger or > or = 65 years of age. Dose-effect analysis revealed a decreased risk of any fracture and fractures at the forearm and hip with an increased number of redeemed defined daily dosages (DDDs) of TD. Therefore, use of more than 2000 DDD was associated with a 19% (95% CI 10% to 27%) decreased hip fracture risk. We conclude that use of TD is associated with a significantly reduced fracture risk.

  6. Design and Evaluation Methods for Underwater Control Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Lin

    1996-12-31

    This thesis on underwater control systems is written with the designer in mind, assuming that the reader has some knowledge of control theory. It can be used as a text for undergraduate students and engineers. To help readers better understand the system they will be working with, the thesis is organised in a stepwise way. The reader will gain basic knowledge about underwater operations, equipment and control systems. Then the reader will be able to follow the steps to develop a required control system for an underwater equipment by first understanding the characteristics of the design problem, customer requirement, functional requirement, and possible solution, and then to present a mathematical model of the control problem. Having developed the concept, the thesis guides the reader to develop evaluation criteria and different ways to make the decision. The thesis gives an overview of how to achieve a successful design rather than giving the techniques for detailed control system design. Chapter 1 describes underwater operations and systems. Chapter 2 discusses issues of underwater control systems and control methods. Chapter 3 deals with design method and control systems theory, focusing on human-centered control. Chapter 4 discusses methods used to evaluate and rank products, and chapter 5 applies the methods to an example. 113 refs., 115 figs., 80 tabs.

  7. Root fractures

    DEFF Research Database (Denmark)

    Andreasen, Jens Ove; Christensen, Søren Steno Ahrensburg; Tsilingaridis, Georgios

    2012-01-01

    The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed.......The purpose of this study was to analyze tooth loss after root fractures and to assess the influence of the type of healing and the location of the root fracture. Furthermore, the actual cause of tooth loss was analyzed....

  8. Performance evaluation and design of flight vehicle control systems

    CERN Document Server

    Falangas, Eric T

    2015-01-01

    This book will help students, control engineers and flight dynamics analysts to model and conduct sophisticated and systemic analyses of early flight vehicle designs controlled with multiple types of effectors and to design and evaluate new vehicle concepts in terms of satisfying mission and performance goals. Performance Evaluation and Design of Flight Vehicle Control Systems begins by creating a dynamic model of a generic flight vehicle that includes a range of elements from airplanes and launch vehicles to re-entry vehicles and spacecraft. The models may include dynamic effects dealing with structural flexibility, as well as dynamic coupling between structures and actuators, propellant sloshing, and aeroelasticity, and they are typically used for control analysis and design. The book shows how to efficiently combine different types of effectors together, such as aero-surfaces, TVC, throttling engines and RCS, to operate as a system by developing a mixing logic atrix. Methods of trimming a vehicle controll...

  9. Integrated Process Design, Control and Analysis of Intensified Chemical Processes

    DEFF Research Database (Denmark)

    Mansouri, Seyed Soheil

    approach is to tackle process design and controllability issues simultaneously, in the early stages of process design. This simultaneous synthesis approach provides optimal/near optimal operation and more efficient control of conventional (non-reactive binary distillation columns) as well as complex...... chemical processes; for example, intensified processes such as reactive distillation. Most importantly, it identifies and eliminates potentially promising design alternatives that may have controllability problems later. To date, a number of methodologies have been proposed and applied on various problems...... design of the process as well as the controller structure. Through analytical, steady-state and closed-loop dynamic analysis it is verified that the control structure, disturbance rejection and energy requirement of the reactive distillation column is better than any other operation point...

  10. Generic Electronic Board Design to Control 3-Phase Ac

    Directory of Open Access Journals (Sweden)

    RojasMolina A.

    2012-01-01

    Full Text Available This work presents the design and development of a low-cost power manager with controller for a 3-phase AC induction motor, with a wide range of industrial applications. The prototype drive design and development was made using the generic standard on printed board design IPC2221. Power manager consists of two stages. First is control stage, which includes an induction motor control-specific micro-controller. Second is power stage, with IGBTs as switching elements. This design is part of a wider project whose main objective is to advance a methodology to assist the quality improvement of academia-developed electronic prototypes. It is expected that these prototypes will be aligned with industrial standards, facilitating the industry-university connection regarding technological collaboration in the automation and control domain.

  11. Fracturing controlled primary migration of hydrocarbon fluids during heating of organic-rich shales

    CERN Document Server

    Kobchenko, Maya; Renard, Francois; Dysthe, Dag Kristian; Malthe-Sorenssen, Anders; Mazzini, Adriano; Scheibert, Julien; Jamtveit, Bjorn; Meakin, Paul

    2011-01-01

    Time-resolved three-dimensional in situ high resolution synchrotron x-ray tomographic imaging was used to investigate the effects of slowly heating organic-rich Green River Shale from 60\\deg; to 400\\deg;C, in air without confinement, to better understand primary migration of hydrocarbon fluids in very low permeability source rock. Cracks nucleate in the interior of the sample at a temperature around 350\\deg;C. As the temperature increases, they grow and coalesce along lamination planes to form bigger cracks. This process is accompanied by a release of light hydrocarbons generated by decomposition of the initially immature organic matter, as determined by thermogravimetry and gas chromatography. These results provide the first 4D monitoring of an invasion percolation-like fracturing process in organic-rich shales. This process increases the permeability of the sample and provides pathways for fluid expulsion - an effect that might also be relevant for primary migration under natural conditions. We propose a 2D...

  12. Stress Fractures

    Science.gov (United States)

    Stress fractures Overview Stress fractures are tiny cracks in a bone. They're caused by repetitive force, often from overuse — such as repeatedly jumping up and down or running long distances. Stress fractures can also arise from normal use of ...

  13. Automatic control system generation for robot design validation

    Science.gov (United States)

    Bacon, James A. (Inventor); English, James D. (Inventor)

    2012-01-01

    The specification and drawings present a new method, system and software product for and apparatus for generating a robotic validation system for a robot design. The robotic validation system for the robot design of a robotic system is automatically generated by converting a robot design into a generic robotic description using a predetermined format, then generating a control system from the generic robotic description and finally updating robot design parameters of the robotic system with an analysis tool using both the generic robot description and the control system.

  14. A control center design revisited: learning from users’ appropriation

    DEFF Research Database (Denmark)

    Souza da Conceição, Carolina; Cordeiro, Cláudia

    2014-01-01

    This paper aims to present the lessons learned during a control center design project by revisiting another control center from the same company designed two and a half years before by the same project team. In light of the experience with the first project and its analysis, the designers...... and researchers had important feedback already used to suggest changes for the second project. The opportunity to learn from a previous project was unique, but the knowledge gotten out of it shows the importance of having this feedback from project to project instead of just ‘repeating’ previously used design...

  15. Disturbance Accommodating Control Design for Wind Turbines Using Solvability Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Na [National Renewable Energy Laboratory,15013 Denver West Parkway,Golden, CO 80401e-mail: na.wang@nrel.gov; Wright, Alan D. [National Renewable Energy Laboratory,15013 Denver West Parkway,Golden, CO 80401e-mail: alan.wright@nrel.gov; Balas, Mark J. [ProfessorFellow ASMEAerospace Engineering Department,Embry-Riddle Aeronautical University,Daytona Beach, FL 32114e-mail: balasm@erau.edu

    2017-02-07

    In this paper, solvability conditions for disturbance accommodating control (DAC) have been discussed and applied on wind turbine controller design in above-rated wind speed to regulate rotor speed and to mitigate turbine structural loads. DAC incorporates a predetermined waveform model and uses it as part of the state-space formulation, which is known as the internal model principle to reduce or minimize the wind disturbance effects on the outputs of the wind turbine. An asymptotically stabilizing DAC controller with disturbance impact on the wind turbine being totally canceled out can be found if certain conditions are fulfilled. Designing a rotor speed regulation controller without steady-state error is important for applying linear control methodology such as DAC on wind turbines. Therefore, solvability conditions of DAC without steady-state error are attractive and can be taken as examples when designing a multitask turbine controller. DAC controllers solved via Moore-Penrose Pseudoinverse and the Kronecker product are discussed, and solvability conditions of using them are given. Additionally, a new solvability condition based on inverting the feed-through D term is proposed for the sake of reducing computational burden in the Kronecker product. Applications of designing collective pitch and independent pitch controllers based on DAC are presented. Recommendations of designing a DAC-based wind turbine controller are given. A DAC controller motivated by the proposed solvability condition that utilizes the inverse of feed-through D term is developed to mitigate the blade flapwise once-per-revolution bending moment together with a standard proportional integral controller in the control loop to assist rotor speed regulation. Simulation studies verify the discussed solvability conditions of DAC and show the effectiveness of the proposed DAC control design methodology.

  16. Designing a robust minimum variance controller using discrete slide mode controller approach.

    Science.gov (United States)

    Alipouri, Yousef; Poshtan, Javad

    2013-03-01

    Designing minimum variance controllers (MVC) for nonlinear systems is confronted with many difficulties. The methods able to identify MIMO nonlinear systems are scarce. Harsh control signals produced by MVC are among other disadvantages of this controller. Besides, MVC is not a robust controller. In this article, the Vector ARX (VARX) model is used for simultaneously modeling the system and disturbance in order to tackle these disadvantages. For ensuring the robustness of the control loop, the discrete slide mode controller design approach is used in designing MVC and generalized MVC (GMVC). The proposed method for controller design is tested on a nonlinear experimental Four-Tank benchmark process and is compared with nonlinear MVCs designed by neural networks. In spite of the simplicity of designing GMVCs for the VARX models with uncertainty, the results show that the proposed method is accurate and implementable.

  17. Influence of remaining coronal structure and of the marginal design on the fracture strength of roots restored with cast post and core.

    Science.gov (United States)

    Carlini-Júnior, Bruno; Cecchin, Doglas; Farina, Ana P; Pereira, Gisele D S; Prieto, Lúcia T; Paulillo, Luis A M S

    2013-01-01

    The purpose of this study was to evaluate the fracture strength of roots that were prosthetically restored with cast post and core with or without any remaining coronal structure and with different finish lines. Sixty bovine incisors were sectioned below the cementoenamel junction, endodontically treated and randomly divided into six experimental groups (n = 10) containing teeth with or without any remaining coronal structure and with a beveled shoulder, a chanfered or a shoulder finish line design. The cast post and core were luted with dual-cured resin cement. The metal crowns were cemented with zinc phosphate cement. The specimens were subjected to a tangential compressive load (135° angle) at a crosshead speed of 0.5 mm/min until failure, using a universal testing machine. The fracture strength data were analyzed using the ANOVA and LSMeans (least square means) tests (α = 0.05). The data indicated that the teeth with 2 mm of remaining coronal structure showed the highest fracture strength values when compared with the teeth without any remaining structure (p strength values were obtained for the beveled shoulder, followed by the chanfered and then by the shoulder designs (p strength, a beveled shoulder and 2 mm of remaining coronal structure are the ideal conditions.

  18. Study on orientation fracture blasting with shaped charge in rock

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    On the basis of the theories of mechanics of explosive and rock fracture mechanics, the mechanism of crack initiation and its expansion of directional fracture controlled blasting with shaped charges in rock were studied, then the blasting parameters were designed and tested by a model test in laboratory and field experiment. The experimental and test results showed that the energy from blasting is directionally concentrated for the cumulative action. The directional expansion of cracks is satisfactory, the results of the model test and field test suggested that the orientation fracture blasting with shaped charge is a good means of excavating tunnels or cutting rock.

  19. Design of energy-based terrain following flight control system

    Science.gov (United States)

    Wang, Wei; Li, Aijun; Xie, Yanwu; Tan, Jian

    2006-11-01

    Historically, aircraft longitudinal control has been realized by means of two loops: flight path (the control variable is elevator displacement) and speed control (the control variable is propulsive thrust or engine power). Both the elevator and throttle control cause coupled altitude and speed response, which exerts negative effects on longitudinal flight performance of aircraft, especially for Terrain Following(TF) flight. Energy-based method can resolve coupled problem between flight speed and path by controlling total energy rate and energy distribution rate between elevator and throttle. In this paper, energy-based control method is applied to design a TF flight control system for controlling flight altitude directly. An error control method of airspeed and altitude is adopted to eliminate the stable error of the total energy control system when decoupling control. Pitch loop and pitch rate feedback loop are designed for the system to damp the oscillatory response produced by TF system. The TF flight control system structure diagram and an aircraft point-mass energy motion model including basic control loops are given and used to simulate decoupling performance of the TF fight control system. Simulation results show that the energy-based TF flight control system can decouple flight velocity and flight path angle, exactly follow planned flight path, and greatly reduce altitude error, which is between +10m and -8m.

  20. Designing for Damage: Robust Flight Control Design using Sliding Mode Techniques

    Science.gov (United States)

    Vetter, T. K.; Wells, S. R.; Hess, Ronald A.; Bacon, Barton (Technical Monitor); Davidson, John (Technical Monitor)

    2002-01-01

    A brief review of sliding model control is undertaken, with particular emphasis upon the effects of neglected parasitic dynamics. Sliding model control design is interpreted in the frequency domain. The inclusion of asymptotic observers and control 'hedging' is shown to reduce the effects of neglected parasitic dynamics. An investigation into the application of observer-based sliding mode control to the robust longitudinal control of a highly unstable is described. The sliding mode controller is shown to exhibit stability and performance robustness superior to that of a classical loop-shaped design when significant changes in vehicle and actuator dynamics are employed to model airframe damage.