[Experimental psychological research on the level of pretensions in alcoholics taking the sex factor into account].

PubMed

Meerzon, M M

1987-01-01

An experimental psychological study has involved 50 males and 53 females with Stage I-II alcoholism during their first hospitalization. The studied patients presented an extravert-neurotic type of personality degradation. Abnormalities of motivational activity in an experimental situation of choice were characterized by a very low level of pretensions in male alcoholics and the maximum level of pretensions in female alcoholics. An analysis of intellectual productivity of the patients has indicated a low intellectual output and inability of the rational utilization of the intellectual potential. In view of the heterogeneity of affective disturbances in men and women, the author recommends a differential psychotherapeutical approach to alcoholic patients of different sex.

Self-Admitted Pretensions of Mac Users on a Predominantly PC University Campus

ERIC Educational Resources Information Center

Firmin, Michael W.; Wood, Whitney L. Muhlenkamp; Firmin, Ruth L.; Wood, Jordan C.

2010-01-01

The present qualitative research study addressed the overall research question of college students' pretention dynamics in the context of a university setting. Thirty-five Mac users were interviewed on a university campus that exclusively supports PC machines. Mac users shared four self-admitted pretensions related to using Macintosh computers.…

Children's Developing Knowledge of the Relationship Between Mental Awareness and Pretense

ERIC Educational Resources Information Center

Sobel, David M.

2004-01-01

This study investigated 3- and 4-year-old's understanding of the relationship between pretense and mental awareness. In Experiments 1 and 2, only a subset of 4-year-olds recognized that sleeping characters and characters ignorant of their appearance were not pretending. However, these experiments had certain linguistic demands, which potentially…

The Relation between Individual Differences in Fantasy and Theory of Mind.

ERIC Educational Resources Information Center

Taylor, Marjorie; Carlson, Stephanie M.

1997-01-01

Examined relation between early fantasy/pretense and knowledge about mental life in 3- and 4-year olds. Found that performance on theory of mind tasks was significantly intercorrelated when effects of verbal intelligence and age were statistically controlled. Individual differences in fantasy/pretense were related to theory of mind performance in…

Shape accuracy optimization for cable-rib tension deployable antenna structure with tensioned cables

NASA Astrophysics Data System (ADS)

Liu, Ruiwei; Guo, Hongwei; Liu, Rongqiang; Wang, Hongxiang; Tang, Dewei; Song, Xiaoke

2017-11-01

Shape accuracy is of substantial importance in deployable structures as the demand for large-scale deployable structures in various fields, especially in aerospace engineering, increases. The main purpose of this paper is to present a shape accuracy optimization method to find the optimal pretensions for the desired shape of cable-rib tension deployable antenna structure with tensioned cables. First, an analysis model of the deployable structure is established by using finite element method. In this model, geometrical nonlinearity is considered for the cable element and beam element. Flexible deformations of the deployable structure under the action of cable network and tensioned cables are subsequently analyzed separately. Moreover, the influence of pretension of tensioned cables on natural frequencies is studied. Based on the results, a genetic algorithm is used to find a set of reasonable pretension and thus minimize structural deformation under the first natural frequency constraint. Finally, numerical simulations are presented to analyze the deployable structure under two kinds of constraints. Results show that the shape accuracy and natural frequencies of deployable structure can be effectively improved by pretension optimization.

Relationship between locking-bolt torque and load pre-tension in the Ilizarov frame.

PubMed

Osei, N A; Bradley, B M; Culpan, P; Mitchell, J B; Barry, M; Tanner, K E

2006-10-01

The wire-bolt interface in an Ilizarov frame has been mechanically tested. The optimal torque to be applied to the frame locking-bolts during physiological loading has been defined. The set-up configuration was as is used clinically except a copper tube was used to simulate bone. The force-displacement curves of the Ilizarov wires are not altered by locking-bolt torque. The force in the bone model at which pre-tension is lost increases as the locking-bolts are tightened to 14 Nm torque, but decreases if torque exceeds 14 Nm. Thus, 14 Nm is the optimal locking-bolt torque in frame. The relationship between pre-tension versus load for different locking-bolt torques arises because at low and high clamping torques poor wire holding and plastic deformation respectively occur. Wire damage was seen under light and electron microscopy. Clinically, over or under-tightening locking-bolts will cause loss of pre-tension, reduction in frame stiffness and excessive movement at the fracture site, which may be associated with delayed union.

Preschoolers Acquire General Knowledge by Sharing in Pretense

ERIC Educational Resources Information Center

Sutherland, Shelbie L.; Friedman, Ori

2012-01-01

Children acquire general knowledge about many kinds of things, but there are few known means by which this knowledge is acquired. In this article, it is proposed that children acquire generic knowledge by sharing in pretend play. In Experiment 1, twenty-two 3- to 4-year-olds watched pretense in which a puppet represented a "nerp" (an unfamiliar…

Play and Cognition: A Study of Pretense Play and Conservation of Quantity.

ERIC Educational Resources Information Center

Golomb, Claire; Friedman, Laura

The relative effectiveness of four different training conditions on the attainment of conservation of quantity was examined in a 5-Group design. Subjects were 75 nonconserving preschoolers, ranging in age from 3.10 to 5.0 years. Treatment consisted of five conditions: (1) pretense play training, (2) direct conservation training, (3) a combination…

45 CFR 2508.18 - What are the penalties for obtaining a record under false pretenses?

Code of Federal Regulations, 2010 CFR

2010-10-01

... (Continued) CORPORATION FOR NATIONAL AND COMMUNITY SERVICE IMPLEMENTATION OF THE PRIVACY ACT OF 1974 § 2508.18 What are the penalties for obtaining a record under false pretenses? The Privacy Act provides, in pertinent part that: (a) Any person who knowingly and willfully requests to obtain any record concerning an...

Driver kinematic and muscle responses in braking events with standard and reversible pre-tensioned restraints: validation data for human models.

PubMed

Osth, Jonas; Olafsdóttir, Jóna Marín; Davidsson, Johan; Brolin, Karin

2013-11-01

The objectives of this study are to generate validation data for human models intended for simulation of occupant kinematics in a pre-crash phase, and to evaluate the effect of an integrated safety system on driver kinematics and muscle responses. Eleven male and nine female volunteers, driving a passenger car on ordinary roads, performed maximum voluntary braking; they were also subjected to autonomous braking events with both standard and reversible pre-tensioned restraints. Kinematic data was acquired through film analysis, and surface electromyography (EMG) was recorded bilaterally for muscles in the neck, the upper extremities, and lumbar region. Maximum voluntary contractions (MVCs) were carried out in a driving posture for normalization of the EMG. Seat belt positions, interaction forces, and seat indentions were measured. During normal driving, all muscle activity was below 5% of MVC for females and 9% for males. The range of activity during steady state braking for males and females was 13-44% in the cervical and lumbar extensors, while antagonistic muscles showed a co-contraction of 2.3-19%. Seat belt pre-tension affects both the kinematic and muscle responses of drivers. In autonomous braking with standard restraints, muscle activation occurred in response to the inertial load. With pre-tensioned seat belts, EMG onset occurred earlier; between 71 ms and 176 ms after belt pre-tension. The EMG onset times decreased with repeated trials and were shorter for females than for males. With the results from this study, further improvement and validation of human models that incorporate active musculature will be made possible.

Detailed finite element analysis and preliminary study of the effects of friction and fastener pre-tension on the mechanical behavior of fastened built-up members

NASA Astrophysics Data System (ADS)

Bonachera Martin, Francisco Javier

The characterization of fatigue resistance is one of the main concerns in structural engineering, a concern that is particularly important in the evaluation of existing bridge members designed or erected before the development of fatigue design provisions. The ability of a structural member to develop alternate load paths after the failure of a component is known as member-level or internal redundancy. In fastened built-up members, these alternate load paths are affected by the combination of fastener pre-tension and friction between the structural member components in contact. In this study, a finite element methodology to model and analyze riveted and bolted built-up members was developed in ABAQUS and validated with experimental results. This methodology was used to created finite element models of three fastened plates subjected to tension, in which the middle plate had failed, in order to investigate the fundamental effects of combined fastener pre-tension and friction on their mechanical behavior. Detailed finite element models of riveted and bolted built-up flexural members were created and analyze to understand the effect of fastener pre-tension in member-level redundancy and resistance to fatigue and fracture. The obtained results showed that bolted members are able to re-distribute a larger portion of the load away from the failing component into the rest of the member than riveted members, and that this transfer of load also took place over a smaller length. Superior pre-tension of bolts, in comparison to rivets, results in larger frictional forces that develop at the contact interfaces between components and constitute additional alternate load paths that increase member-level redundancy which increase the fatigue and fracture resistance of the structural member during the failure of one of its components. Although fatigue and fracture potential may be mitigated by compressive stresses developing around the fastener hole due to fastener pre-tension, it was also observed, that at the surface of the fastener hole and at the contact interface with another plate, tensional stresses could develop; however, further computational and experimental work should be performed to verify this claim.

Composite resin reinforced with pre-tensioned glass fibers. Influence of prestressing on flexural properties.

PubMed

Schlichting, Luís Henrique; de Andrada, Mauro Amaral Caldeira; Vieira, Luiz Clóvis Cardoso; de Oliveira Barra, Guilherme Mariz; Magne, Pascal

2010-02-01

This investigation evaluated the flexural properties of two composite resins, and the influence of unidirectional glass fiber reinforcements, with and without pre-tensioning. Two composite resins (Q: Quixfil and A: Adoro) were used to fabricate 2 mm x 2 mm x 25 mm beams (N = 10), reinforced with two fiber bundles along the long axis of the beam and pre-tensioned under a load equivalent to 73.5% of its tensile strength (groups QPF and APF). In two other experimental groups, the bundles were similarly positioned but without pre-tension (groups QF and AF). Two more groups were included without fiber reinforcement (control groups Q and A). After 24h storage, specimens were subjected to a three-point flexural bending test to establish the flexural module, the deflection at initial failure and the flexural strength. Data were analyzed using a two-way analysis of variance (composite resin system and fiber reinforcement type) and the Tukey HSD post hoc tests (alpha = .05). The results showed that prestressing increased the flexural module of Adoro specimens (p<.001) but not Quixfil (p = .17). Prestressed beams reached greater deflection at initial failure than those conventionally reinforced (p<.001), namely .85-1.35 mm for Adoro and .66-.90 mm for Quixfil. Prestressing also significantly increased the flexural strength of beams (p<.001) in both Adoro and Quixfil groups, from 443.46 to 569.15 MPa and from 425.47 to 568.00 MPa, respectively. Pre-tensioning of unidirectional glass fibers increased both deflection until initial failure and flexural strength of Quixfil and Adoro composite resins, however, with limited effects on the flexural modulus. Copyright 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Numerical Analysis of Effectiveness of Strengthening Concrete Slab in Tension of the Steel-Concrete Composite Beam Using Pretensioned CFRP Strips

NASA Astrophysics Data System (ADS)

Jankowiak, Iwona; Madaj, Arkadiusz

2017-12-01

One of the methods to increase the load carrying capacity of the reinforced concrete (RC) structure is its strengthening by using carbon fiber (CFRP) strips. There are two methods of strengthening using CFRP strips - passive method and active method. In the passive method a strip is applied to the concrete surface without initial strains, unlike in the active method a strip is initially pretensioned before its application. In the case of a steel-concrete composite beam, strips may be used to strengthen the concrete slab located in the tension zone (in the parts of beams with negative bending moments). The finite element model has been developed and validated by experimental tests to evaluate the strengthening efficiency of the composite girder with pretensioned CFRP strips applied to concrete slab in its tension zone.

Is It Oscar-Worthy? Children’s Metarepresentational Understanding of Acting

PubMed Central

Goldstein, Thalia R.; Bloom, Paul

2015-01-01

Although it is an essential aspect of one of the most common forms of entertainment, psychologists know almost nothing about how children understand the act of portraying a character in a realistic manner—realistic acting. Do children possess the sort of meta-theory of acting that adults possess? In two studies we find that, unlike adults, children between the ages of 3–5 do not think that a realistic actor is better at portraying a characteristic than a nonrealistic actor, nor do they prefer one to the other. As they develop, they come to understand that realistic acting is different from nonrealistic acting, but unlike adults, children think that a nonrealistic, pretense-like portrayal is more difficult to achieve than a realistic representation of an emotional or physical state. These findings show that children’s metarepresentational understanding of acting is relatively immature at age 5, and that their understanding of this specific domain of pretense lags behind their understanding of pretense in general. PMID:25761111

Effect of Technological Tensioning on the Efficiency of Reinforcement of Pipelines with Composite Bands

NASA Astrophysics Data System (ADS)

Barkanov, E.; Beschetnikov, D.; Lvov, G.

2015-01-01

A mathematical model for the contact interaction of a cylindrical pipe with a composite band during its repair is constructed. A system of governing equations of the contact problem is formulated by using the Timoshenko theory of shells. An analysis of possible solutions is carried out for various combinations of geometric and elastic properties of shells. The possibility of pretension of a prepreg in order to improve the efficiency of repair is considered. The numerical results obtained allow one to establish the desired level of pretension for various repair situations.

Thermal insulation of a cryogenic tank for a space telescope using a pretensioned suspension of Fiber Reinforced Composite (FRC)

NASA Astrophysics Data System (ADS)

Bongers, Bernd; Haider, Otmar; Tauber, Wolfgang

1990-09-01

For the thermal insulation of cryogenic tanks in satellite applications Fiber Reinforced Composite (FRC) materials are preferable because of their low thermal conductivity and high tensile strength compared to metallic materials. At the Infrared Space Observatory (ISO) satellite the main Liquid Helium (LHe) tank is suspended by one spatial framework and eight pretensioned chain strands at each side. Frameworks and chain strands are acting as a thermal barrier and therefore made of FRC. To meet the various and, in parts contractive requirements, sophisticated design approaches are chosen for the structural parts.

Enactive account of pretend play and its application to therapy

PubMed Central

Rucinska, Zuzanna; Reijmers, Ellen

2015-01-01

This paper informs therapeutic practices that use play, by providing a non-standard philosophical account of pretense: the enactive account of pretend play (EAPP). The EAPP holds that pretend play activity need not invoke mental representational mechanisms; instead, it focuses on interaction and the role of affordances in shaping pretend play activity. One advantage of this re-characterization of pretense is that it may help us better understand the role of shared meanings and interacting in systemic therapies, which use playing to enhance dialog in therapy rather than to uncover hidden meanings. We conclude with bringing together findings from therapeutic practice and philosophical considerations. PMID:25784884

Audio-based bolt-loosening detection technique of bolt joint

NASA Astrophysics Data System (ADS)

Zhang, Yang; Zhao, Xuefeng; Su, Wensheng; Xue, Zhigang

2018-03-01

Bolt joint, as the commonest coupling structure, is widely used in electro-mechanical system. However, it is the weakest part of the whole system. The increase of preload tension force can raise the reliability and strength of the bolt joint. Therefore, the pretension force is one of the most important factors to ensure the stability of bolt joint. According to the way of generating pretension force, the pretension force can be monitored by bolt torque, degrees and elongation. The existing bolt-loosening monitoring methods all require expensive equipment, which greatly restricts the practicality of the bolt-loosening monitoring. In this paper, a new method of bolt-loosening detection technique based on audio is proposed. The sound that bolt is hit by a hammer is recorded on the Smartphone, and the collected audio signal is classified and identified by support vector machine algorithm. First, a verification test was designed and the results show that this new method can identify the damage of bolt looseness accurately. Second, a variety of bolt-loosening was identified. The results indicate that this method has a high accuracy in multiclass classification of the bolt looseness. This bolt-loosening detection technique based on audio not only can reduce the requirements of technical and professional experience, but also make bolt-loosening monitoring simpler and easier.

Prophylactic neuroprotective efficiency of co-administration of Ginkgo biloba and Trifolium pretense against sodium arsenite-induced neurotoxicity and dementia in different regions of brain and spinal cord of rats.

PubMed

Abdou, Heba M; Yousef, Mokhtar I; El Mekkawy, Desouki A; Al-Shami, Ahmed S

2016-08-01

The present study was carried out to evaluate the potential protective role of co-administration of Ginkgo biloba, Trifolium pretenseagainst sodium arsenite-induced neurotoxicity in different parts of brain (Cerebral cortex, Hippocampus, striatum and Hind brain) and in the spinal cord of rats. Sodium arsenite caused impairment in the acquisition and learning in all the behavioral tasks and caused significant increase in tumor necrosis factor-α,thiobarbituric acid-reactive substances andlipid profile, while caused significant decrease in glutathione, total thiol content, total antioxidant capacity, acetylcholinesterase, monoamine oxidase and ATPases activities. These results were confirmed by histopathological, fluorescence and scanning electron microscopy examination of different regions of brain. From these results sodium arsenite-induced neurodegenerative disorder in different regions of brain and spinal cord and this could be mediated through modifying the intracellular brain ions homeostasis, cholinergic dysfunction and oxidative damage. The presence of Ginkgo biloba and/orTrifolium pretense with sodium arsenite minimized its neurological damages. It was pronounced that using Ginkgo biloba and Trifolium pretense in combination was more effective as protective agents compared to use eachone of them alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Maximum load to failure and tensile displacement of an all-suture glenoid anchor compared with a screw-in glenoid anchor.

PubMed

Dwyer, Tim; Willett, Thomas L; Dold, Andrew P; Petrera, Massimo; Wasserstein, David; Whelan, Danny B; Theodoropoulos, John S

2016-02-01

The purpose of this study was to evaluate the biomechanical behavior of an all-suture glenoid anchor in comparison with a more conventional screw-in glenoid anchor, with regard to maximum load to failure and tensile displacement. All mechanical testing was performed using an Instron ElectroPuls E1000 mechanical machine, with a 10 N pre-load and displacement rate of 10 mm/min. Force-displacement curves were generated, with calculation of maximum load, maximum displacement, displacement at 50 N and stiffness. Pretesting of handset Y-Knots in bone analog models revealed low force displacement below 60 N of force. Subsequently, three groups of anchors were tested for pull out strength in bovine bone and cadaver glenoid bone: a bioabsorbable screw-in anchor (Bio Mini-Revo, ConMed Linvatec), a handset all-suture anchor (Y-Knot, ConMed Linvatec) and a 60 N pre-tensioned all-suture anchor (Y-Knot). A total of 8 anchors from each group was tested in proximal tibia of bovine bone and human glenoids (age range 50-90). In bovine bone, the Bio Mini-Revo displayed greater maximum load to failure (206 ± 77 N) than both the handset (140 ± 51 N; P = 0.01) and the pre-tensioned Y-Knot (135 ± 46 N; P = 0.001); no significant difference was seen between the three anchor groups in glenoid bone. Compared to the screw-in anchors, the handset all-suture anchor displayed inferior fixation, early displacement and greater laxity in the bovine bone and cadaveric bone (P < 0.05). Pre-tensioning the all-suture anchor to 60 N eliminated this behavior in all bone models. Handset Y-Knots display low force anchor displacement, which is likely due to slippage in the pilot hole. Pre-tensioning the Y-Knot to 60 N eliminates this behavior. I.

Appendix B : small beam tests.

DOT National Transportation Integrated Search

2013-03-01

The AASHTO LRFD Bridge Design Specifications (2007) require that confinement : reinforcement be placed around prestressing strands in the bottom bulb of pretensioned concrete : beams. Although the AASHTO specifications contain prescriptive requiremen...

Development length of 0.6-inch prestressing strand in standard I-shaped pretensioned concrete beams

NASA Astrophysics Data System (ADS)

Barnes, Robert Wesley

The use of 0.6 in prestressing strand at a center-to-center spacing of 2 in allows for the optimal implementation of High Strength Concrete (HSC) in precast, prestressed concrete bridge superstructures. For this strand configuration, partial debonding of strands is a desirable alternative to the more traditional method of draping strands to alleviate extreme concrete stresses after prestress release. Recent experimental evidence suggests that existing code provisions addressing the anchorage of pretensioned strands do not adequately describe the behavior of these strands. In addition, the anchorage behavior of partially debonded strands is not fully understood. These uncertainties have combined to hinder the full exploitation of HSC in pretensioned concrete construction. A research study was conducted to determine the anchorage behavior of 0.6 in strands at 2 in spacing in full-size bridge members. The experimental program consisted of assessing transfer and development lengths in plant-cast AASHTO Type I I-beams. The influence of concrete compressive strengths ranging from 5700 to 14,700 psi was examined. In order to consider the full range of strand surface conditions found in practice, the prestressing strand featured either a bright mill finish or a rusted surface condition. The anchorage behavior of partially debonded strands was investigated by using a variety of strand debonding configurations---including debonded strand percentages as high as 75 percent. A limited investigation of the effect of horizontal web reinforcement on anchorage behavior was performed. Pull-out tests were performed in an attempt to correlate results with the bond quality of the strands used in the study. The correlation between strand draw-in and the anchorage behavior of prestressing strands was also examined. A review of the evolution and shortcomings of existing code provisions for the anchorage of prestressing strands is presented. Results of the experimental program are reported, along with recommended design procedures based on these results and those from other studies. The use of 0.6 in strand at 2 in spacing is concluded to be safe, and partial debonding of prestressing strands is shown to be an effective means of reducing stresses in the end regions of pretensioned girders.

Appendix D : FIB-54 tests.

DOT National Transportation Integrated Search

2013-03-01

Confinement reinforcement is placed near the end of pretensioned concrete I-girders to : enclose prestressing strands in the bottom flange. Experimental and analytical test programs : were conducted to investigate the function of confinement reinforc...

32 CFR 505.12 - Privacy Act enforcement actions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... AUTHORITIES AND PUBLIC RELATIONS ARMY PRIVACY ACT PROGRAM § 505.12 Privacy Act enforcement actions. (a... record under false pretenses; or (iii) Maintaining a system of records without first meeting the public...

Appendix G : end region design models.

DOT National Transportation Integrated Search

2013-03-01

The 2007 AASHTO LRFD Bridge Design Specifications contain prescriptive : requirements for the quantity and placement of confinement reinforcement located in the bottom : flange of pretensioned concrete I-girders. This chapter proposes a rational mode...

Parameters sensitivity on mooring loads of ship-shaped FPSOs

NASA Astrophysics Data System (ADS)

Hasan, Mohammad Saidee

2017-12-01

The work in this paper is focused on special assessment and evaluation of mooring system of ship-shaped FPSO unit. In particular, the purpose of the study is to find the impact on mooring loads for the variation in different parameters using MIMOSA software. First, a selected base case was designed for an intact mooring system in a typical ultimate limit state (ULS) condition, and then the sensitivity to mooring loads on parameters e.g. location of the turret, analysis method (quasi-static vs. dynamic analysis), low-frequency damping level in the surge, pretension and drag coefficients on chain and steel wire has been performed. It is found that mooring loads change due to the change of these parameters. Especially, pretension has a large impact on the maximum tension of mooring lines and low-frequency damping can change surge offset significantly.

Preschoolers acquire general knowledge by sharing in pretense.

PubMed

Sutherland, Shelbie L; Friedman, Ori

2012-01-01

Children acquire general knowledge about many kinds of things, but there are few known means by which this knowledge is acquired. In this article, it is proposed that children acquire generic knowledge by sharing in pretend play. In Experiment 1, twenty-two 3- to 4-year-olds watched pretense in which a puppet represented a "nerp" (an unfamiliar kind of animal). For instance, in one scenario, the nerp ate and disliked a carrot. When subsequently asked generic questions about real nerps, children's responses suggested that they had learned general facts (e.g., nerps dislike carrots). In Experiment 2, thirty-two 4- to 5-year-olds learned from scenarios lacking pretend speech or sound effects. The findings reveal a long overlooked means by which children can acquire generic knowledge. © 2012 The Authors. Child Development © 2012 Society for Research in Child Development, Inc.

Behavior of an adaptive bio-inspired spider web

NASA Astrophysics Data System (ADS)

Zheng, Lingyue; Behrooz, Majid; Huie, Andrew; Hartman, Alex; Gordaninejad, Faramarz

2015-03-01

The goal of this study is to demonstrate the feasibility of an artificial adaptive spider web with comparable behavior to a real spider web. First, the natural frequency and energy absorption ability of a passive web is studied. Next, a control system that consists of stepper motors, load cells and an Arduino, is constructed to mimic a spider's ability to control the tension of radial strings in the web. The energy related characteristics in the artificial spider web is examined while the pre-tension of the radial strings are varied. Various mechanical properties of a damaged spider web are adjusted to study their effect on the behavior of the web. It is demonstrated that the pre-tension and stiffness of the web's radial strings can significantly affect the natural frequency and the total energy of the full and damaged webs.

Dramatic pretend play games uniquely improve emotional control in young children.

PubMed

Goldstein, Thalia R; Lerner, Matthew D

2017-09-15

Pretense is a naturally occurring, apparently universal activity for typically developing children. Yet its function and effects remain unclear. One theorized possibility is that pretense activities, such as dramatic pretend play games, are a possible causal path to improve children's emotional development. Social and emotional skills, particularly emotional control, are critically important for social development, as well as academic performance and later life success. However, the study of such approaches has been criticized for potential bias and lack of rigor, precluding the ability to make strong causal claims. We conducted a randomized, component control (dismantling) trial of dramatic pretend play games with a low-SES group of 4-year-old children (N = 97) to test whether such practice yields generalized improvements in multiple social and emotional outcomes. We found specific effects of dramatic play games only on emotional self-control. Results suggest that dramatic pretend play games involving physicalizing emotional states and traits, pretending to be animals and human characters, and engaging in pretend scenarios in a small group may improve children's emotional control. These findings have implications for the function of pretense and design of interventions to improve emotional control in typical and atypical populations. Further, they provide support for the unique role of dramatic pretend play games for young children, particularly those from low-income backgrounds. A video abstract of this article can be viewed at: https://youtu.be/2GVNcWKRHPk. © 2017 John Wiley & Sons Ltd.

3-D Analysis of Flanged Joints Through Various Preload Methods Using ANSYS

NASA Astrophysics Data System (ADS)

Murugan, Jeyaraj Paul; Kurian, Thomas; Jayaprakash, Janardhan; Sreedharapanickar, Somanath

2015-10-01

Flanged joints are being employed in aerospace solid rocket motor hardware for the integration of various systems or subsystems. Hence, the design of flanged joints is very important in ensuring the integrity of motor while functioning. As these joints are subjected to higher loads due to internal pressure acting inside the motor chamber, an appropriate preload is required to be applied in this joint before subjecting it to the external load. Preload, also known as clamp load, is applied on the fastener and helps to hold the mating flanges together. Generally preload is simulated as a thermal load and the exact preload is obtained through number of iterations. Infact, more iterations are required when considering the material nonlinearity of the bolt. This way of simulation will take more computational time for generating the required preload. Now a days most commercial software packages use pretension elements for simulating the preload. This element does not require iterations for inducing the preload and it can be solved with single iteration. This approach takes less computational time and thus one can study the characteristics of the joint easily by varying the preload. When the structure contains more number of joints with different sizes of fasteners, pretension elements can be used compared to thermal load approach for simulating each size of fastener. This paper covers the details of analyses carried out simulating the preload through various options viz., preload through thermal, initial state command and pretension element etc. using ANSYS finite element package.

Investigation of negative moment reinforcing in bridge decks.

DOT National Transportation Integrated Search

2015-09-01

Multi-span pre-tensioned pre-stressed concrete beam (PPCB) bridges made continuous usually experience a negative live load : moment region over the intermediate supports. Conventional thinking dictates that sufficient reinforcement must be provided i...

Finite Element Bond Modeling for Indented Wires in Pretensioned Concrete Crossties

DOT National Transportation Integrated Search

2016-04-12

Indented wires have been increasingly employed by : concrete crosstie manufacturers to improve the bond between : prestressing steel reinforcements and concrete, as bond can : affect several critical performance measures, including transfer : length,...

Pretensioned concrete girder end crack control : research brief.

DOT National Transportation Integrated Search

2017-02-01

Research Objectives: : Prove through physical testing and observation that debonding strands can reduce or eliminate critical girder end cracking : Eliminate cracking in the bottom flange of the girders, where cracks could allow moisture to r...

Spread prestressed concrete slab beam bridges.

DOT National Transportation Integrated Search

2015-04-01

TxDOT uses prestressed slab beam bridges for short-span bridges ranging from approximately 3050 ft in : length. These bridges have precast, pretensioned slab beams placed immediately adjacent to one another : with a cast-in-place slab made composi...

Freight facts and figures 2005

DOT National Transportation Integrated Search

2000-05-01

This report describes all aspects of a study to develop a nondestructive evaluation (NDE) system based on the concept of magnetic flux leakage (MFL) to detect corrosion and fracture of prestressing steel in pretensioned and post-tensioned concrete br...

End region detailing of pretensioned concrete bridge girders : [summary].

DOT National Transportation Integrated Search

2013-03-01

Introduction of the Florida-I Beam (FIB) in 2009 renewed interest in prestressed concrete beam design, especially end region details. In this study, University of Florida researchers examined construction detailing at the FIB end region.

Continuous prestressed concrete girder bridges volume 1 : literature review and preliminary designs.

DOT National Transportation Integrated Search

2012-06-01

The Texas Department of Transportation (TxDOT) is currently designing typical highway bridge structures as simply supported using standard precast, pretensioned girders. TxDOT is interested in developing additional economical design alternatives for ...

Improving the accuracy of camber predictions for precast pretensioned concrete beams : [tech transfer summary].

DOT National Transportation Integrated Search

2015-07-01

Implementing the recommendations of this study is expected to significantly : improve the accuracy of camber measurements and predictions and to : ultimately help reduce construction delays, improve bridge serviceability, : and decrease costs.

Cyclic tensile response of a pre-tensioned polyurethane

NASA Astrophysics Data System (ADS)

Nie, Yizhou; Liao, Hangjie; Chen, Weinong W.

2018-05-01

In the research reported in this paper, we subject a polyurethane to uniaxial tensile loading at a quasi-static strain rate, a high strain rate and a jumping strain rate where the specimen is under quasi-static pre-tension and is further subjected to a dynamic cyclic loading using a modified Kolsky tension bar. The results obtained at the quasi-static and high strain rate clearly show that the mechanical response of this material is significantly rate sensitive. The rate-jumping experimental results show that the response of the material behavior is consistent before jumping. After jumping the stress-strain response of the material does not jump to the corresponding high-rate curve. Rather it approaches the high-rate curve asymptotically. A non-linear hyper-viscoelastic (NLHV) model, after having been calibrated by monotonic quasi-static and high-rate experimental results, was found to be capable of describing the material tensile behavior under such rate jumping conditions.

Research regarding stiffness optimization of wires used for joints actuation from an elephant's trunk robotic arm

NASA Astrophysics Data System (ADS)

Ciofu, C.; Stan, G.

2016-11-01

Elephant's trunk robotic arms driven by wires and pulley mechanisms have issues with wires stiffness because of the entailed elastic deformations that is causing errors of positioning. Static and dynamic loads from each joint of the robotic arm affect the stiffness of driving wires and precision positioning. The influence of wires elastic deformation on precision positioning decreases with the increasing of wires stiffness by using different pre-tensioning devices. In this paper, we analyze the variation of driving wires stiffness particularly to each wire driven joint. We obtain optimum wires stiffness variation by using an analytical method that highlights the efficiency of pre-tensioning mechanism. The analysis of driving wires stiffness is necessary for taking appropriate optimization measures of robotic arm dynamic behavior and, thus, for decreasing positioning errors of the elephant's trunk robotic arm with inner actuation through wires/cables.

Investigation of long-term prestress losses in pretensioned high performance concrete girders.

DOT National Transportation Integrated Search

2005-01-01

Effective determination of long-term prestress losses is important in the design of prestressed concrete bridges. Over-predicting prestress losses results in an overly conservative design for service load stresses, and under-predicting prestress loss...

Determination of service stresses in pretensioned beams, final report, December 2009.

DOT National Transportation Integrated Search

2009-12-01

This report presents research on the evaluation of service flexural stresses and cracking moment in prestressed concrete members and on the minimum reinforcement requirements that are currently controlled by the flexural cracking moment. In prestress...

Investigation of negative moment reinforcing in bridge decks : [tech transfer summary].

DOT National Transportation Integrated Search

2015-09-01

Multi-span pre-tensioned pre-stressed concrete beam (PPCB) bridges made : continuous, for live loads, usually may experience a negative total moment : over the intermediate supports, which this research investigated as part of an : investigation into...

Precast, Prestressed Concrete Bent Caps : Volume 2, Design Recommendations and Design Examples

DOT National Transportation Integrated Search

2018-04-01

Recommendations for design of pretensioned bent caps are developed based on the findings of full-scale experimental tests of bent cap subassemblages. Companion examples are provided to demonstrate implementation of the design recommendations. First, ...

Continuous prestressed concrete girder bridges, volume 2 : analysis, testing, and recommendations.

DOT National Transportation Integrated Search

2016-12-01

The Texas Department of Transportation designs typical highway bridge structures as simple span systems using : standard precast, pretensioned girders. Spans are limited to about 150 ft due to weight and length restrictions on : transporting the prec...

Studies on carbon FRP (CFRP) prestressed concrete bridge columns and piles in marine environment.

DOT National Transportation Integrated Search

1998-11-01

The main objective of this study was to investigate the feasibility of using concrete piles pretensioned with Carbon Fiber Reinforced Plastics (CFRP) tendons. The study reviews the available literature on mechanical properties of CFRP reinforcement, ...

Finite element bond models for seven-wire prestressing strands in concrete crossties.

DOT National Transportation Integrated Search

2015-03-23

Seven-wire strands are commonly used in pretensioned : concrete ties, but its bonding mechanism with concrete needs : further examination to provide a better understanding of some : concrete tie failure modes. As a key component in the finite : eleme...

Implementation of 0.7 in. diameter strands in prestressed concrete girders.

DOT National Transportation Integrated Search

2013-03-01

For several years, 0.7 in. diameter strands have been successfully used in cable bridges and for mining applications. Using these large diameter strands at 2 in. by 2 in. spacing in pretensioned concrete girders results in approximately 35% increase ...

Legal Scholarship as a Vocation.

ERIC Educational Resources Information Center

Luban, David

2001-01-01

Explores the more purely theoretical side of the legal scholar's vocation, using Max Weber's text on the scholar's role titled "Science as a Vocation." Discusses the consequences of the tension between law schools' generalist "pretensions" and increasingly specialist character, and Weber's fact/value distinction. (EV)

Clover Biotechnology Research at FAPRU

USDA-ARS?s Scientific Manuscript database

Randy Dinkins (USDA-ARS-FAPRU) is conducting research to determine the utility of using the Medicago Affymetrix Genechip for use with red clover (Trifolium pretense). The Medicago Affymetrix Genechip contains approximately 51,000 probe sets that are derived from Medicago truncatula, 1,800 from Medi...

Comparison of the intradermal irritant threshold concentrations of nine allergens from two different manufacturers in clinically nonallergic dogs in the USA.

PubMed

Foust-Wheatcraft, Desirae A; Dell, Darin L; Rosenkrantz, Wayne S; Griffin, Craig E

2017-12-01

The intradermal irritant threshold concentration for many allergens is unknown. To determine the intradermal irritant threshold concentration (ITC) of nine allergens from two different manufacturers. Twenty privately owned clinically nonallergic dogs. Alternaria, cat dander, Dermatophagoides farinae, Chenopodium album (lamb's quarter), Xanthium strumarium (cocklebur), Prosopis glandulosa (mesquite), Morus alba (white mulberry), Cynodon dactylon (Bermuda grass) and Phleum pretense (Timothy grass) from two manufacturers (ALK; Round Rock, TX, USA and Greer ® Laboratories; Lenoir, NC, USA) were injected intradermally at two dilutions and at 15 and 30 min evaluated subjectively (1-4) and objectively (horizontal wheal diameter) by two blinded investigators. A subjective score of 3 or 4 by either investigator at either timed reading was considered positive. If both concentrations resulted in positive reactions, two additional dilutions were performed. The ITC was defined as the lowest tested concentration that elicited a positive reaction in ≥10% of animals. The ITCs were Alternaria >2,000 PNU/mL; cat dander 750 PNU/mL (ALK) and 2,000 PNU/mL (Greer ® ); D. farinae <1:10,000 w/v; C. album <6,000 PNU/mL; X. strumarium <6,000 PNU/mL; P. glandulosa <500 PNU/mL; M. alba <6,000 PNU/mL; C. dactylon <10,000 PNU/mL (ALK) and <6,000 PNU/mL (Greer ® ); and P. pretense <6,000 PNU/mL. There were significant differences in subjective scoring and objective measurement between manufacturers for Alternaria, cat dander and P. pretense. Results revealed significant positive correlation between subjective scoring and objective measurement for each time, investigator and manufacturer separately. © 2017 ESVD and ACVD.

Effects of pretension on work and power output of the muscle-tendon complex in dynamic elbow flexion.

PubMed

Wakayama, Akinobu; Nagano, Akinori; Hay, Dean; Fukashiro, Senshi

2005-06-01

The purpose of the present study was to investigate the effects of pretension on work and power output of the muscle-tendon complex during dynamic elbow flexion under several submaximal and maximal conditions. The subjects were 10 healthy female students. Randomized trials from 0% to 100% maximal voluntary contraction (MVC) pretension (PT) at 60 degrees elbow flexion were conducted. After about 3 s of static PT, subjects maximally flexed the elbow joint to 90 degrees using a quick release method. The weight was individually selected for each subject to provide an optimal load for the development of maximal power. A Hill-type model was utilized to analyze the performance of the elbow muscle-tendon complex (MTC). PT 0, 30, 60 and 90% MVC data were used for comparison, and all data were expressed as the mean and standard deviation. Multiple paired comparisons between the value of PT 0% MVC and that of the other PT levels were performed post-hoc using Dunnett's method. The work of the series elastic component (SEC) increased gradually with the PT level because elastic energy was stored in the PT phase. However, the work of the contractile component (CC) decreased gradually with an increase in PT level. Moreover, the work of the MTC also decreased, closely related to the CC work decrement. The phenomenon of CC work decrement was caused by force depression and was not related to either the force-length or force-velocity relationships of the CC. EMG activity (agonist and antagonist) showed no significant differences. Muscle geometry changes or intracellular chemical shifts may have occurred in the PT phase.

Influence of motion coupling and nonlinear effects on parametric roll for a floating production storage and offloading platform.

PubMed

Greco, M; Lugni, C; Faltinsen, O M

2015-01-28

Occurrence and features of parametric roll (PR) on a weather-vaning floating production storage and offloading (FPSO) platform with a turret single-point mooring-line system are examined. The main focus is on the relevance of motions coupling and nonlinear effects on this phenomenon and on more general unstable conditions as well as on the occurrence and severity of water on deck. This work was motivated by recent experiments on an FPSO model without mooring systems highlighting the occurrence of parametric resonance owing to roll-yaw coupling. A three-dimensional numerical hybrid potential-flow seakeeping solver was able to capture this behaviour. The same method, extended to include the mooring lines, is adopted here to investigate the platform behaviour for different incident wavelengths, steepnesses, headings, locations of the turret and pretensions. From the results, sway and yaw tend to destabilize the system, also bringing chaotic features. The sway-roll-yaw coupling widens the existence region of PR resonance and increases PR severity; it also results in a larger amount of shipped water, especially at smaller wavelength-to-ship length ratio and larger steepness. The chaotic features are excited when a sufficiently large yaw amplitude is reached. Consistently, a simplified stability analysis showed the relevance of nonlinear-restoring coefficients, first those connected with the sway-yaw coupling then those associated with the roll-yaw coupling, both destabilizing. From the stability analysis, the system is unstable for all longitudinal locations of the turret and pre-tensions examined, but the instability weakens as the turret is moved forward, and the pre-tension is increased. The use of a suitable dynamic-positioning system can control the horizontal motions, avoiding the instability. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Influence of motion coupling and nonlinear effects on parametric roll for a floating production storage and offloading platform

PubMed Central

Greco, M.; Lugni, C.; Faltinsen, O. M.

2015-01-01

Occurrence and features of parametric roll (PR) on a weather-vaning floating production storage and offloading (FPSO) platform with a turret single-point mooring-line system are examined. The main focus is on the relevance of motions coupling and nonlinear effects on this phenomenon and on more general unstable conditions as well as on the occurrence and severity of water on deck. This work was motivated by recent experiments on an FPSO model without mooring systems highlighting the occurrence of parametric resonance owing to roll–yaw coupling. A three-dimensional numerical hybrid potential-flow seakeeping solver was able to capture this behaviour. The same method, extended to include the mooring lines, is adopted here to investigate the platform behaviour for different incident wavelengths, steepnesses, headings, locations of the turret and pretensions. From the results, sway and yaw tend to destabilize the system, also bringing chaotic features. The sway–roll–yaw coupling widens the existence region of PR resonance and increases PR severity; it also results in a larger amount of shipped water, especially at smaller wavelength-to-ship length ratio and larger steepness. The chaotic features are excited when a sufficiently large yaw amplitude is reached. Consistently, a simplified stability analysis showed the relevance of nonlinear-restoring coefficients, first those connected with the sway–yaw coupling then those associated with the roll–yaw coupling, both destabilizing. From the stability analysis, the system is unstable for all longitudinal locations of the turret and pre-tensions examined, but the instability weakens as the turret is moved forward, and the pre-tension is increased. The use of a suitable dynamic-positioning system can control the horizontal motions, avoiding the instability. PMID:25512590

Rosencrantz & Guildenstern Are Alive in the Classroom.

ERIC Educational Resources Information Center

Quinn, James E.

1969-01-01

Tom Stoppard's play, "Rosencrantz and Guildenstern Are Dead," focuses on the antics and tragedy of two minor characters in Shakespeare's "Hamlet." Although satirical of their philosophical pretensions, the play conveys the uncertainty and confusion of its two principal characters and thus reflects modern man's dilemma. The…

Clover, Red (Trifolium pretense)

USDA-ARS?s Scientific Manuscript database

Genetic modification of plants by the insertion of transgenes can be a powerful experimental approach to answer basic questions about gene product function. This technology can also be used to make improved crop varieties for use in the field. To apply this powerful tool to red clover, an important ...

32 CFR 310.48 - Criminal penalties.

Code of Federal Regulations, 2010 CFR

2010-07-01

... National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) PRIVACY PROGRAM DOD PRIVACY PROGRAM Privacy Act Violations § 310.48 Criminal penalties. (a) The Act also provides... requests or obtains access to any record concerning another individual under false pretenses may be found...

Understanding Teasing: Lessons from Children with Autism.

ERIC Educational Resources Information Center

Herrey, Erin A.; Capps, Lisa M.; Keltner, Dacher; Kring, Ann M.

2005-01-01

Teasing requires the ability to understand intention, nonliteral communication, pretense, and social context. Children with autism experience difficulty with such skills, and consequently, are expected to have difficulty with teasing. To better understand teasing concepts and behaviors, children with autism, their parents, and age and…

Self-assembly of suspended graphene wrinkles with high pre-tension and elastic property

NASA Astrophysics Data System (ADS)

Yang, Liusi; Niu, Tianxiao; Zhang, Hui; Xu, Wenjing; Zou, Mingchu; Xu, Lu; Cao, Guoxin; Cao, Anyuan

2017-12-01

Wrinkles exist universally in graphene-based structures, yet their controlled fabrication remains challenging; most graphene wrinkles have been produced either in attachment to elastic substrates or limited in small single sheets. Here, we utilize the phenomenon of gel-cracking to generate uniaxial strains locally on solution-precipitated graphene oxide (GO) sheets, thus creating suspended and aligned wrinkles over the trenches between cracked TiO2 islands. In particular, those GO wrinkles are subjected to a high pre-tension, which is important for making stable suspended configuration, as confirmed by theoretical calculations based on the wrinkle geometry and measured spring constants, respectively. As a result, in situ atomic force microscope indentation reveals elastic deformation with tunable spring constants depending on the gap width. We further obtain chemically reduced GO wrinkles with enhanced spring constants and reversible behavior after 1000 indentation cycles. Our suspended and aligned graphene wrinkles have potential applications in many areas such as sensors, actuators, and micro/nano electromechanical systems.

Rock Music and Sex

ERIC Educational Resources Information Center

Goldberg, Herb

1971-01-01

It is the fear of this author that this generation, stupefied by their own self-indulgence, deluded by their pretensions of lovingness, unconsciously motivated by intense intimacy-anxiety, while projecting their conflict on ready targets such as the Establishment and the police, might be fertile ground for a destructive dictator. (Author)

Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : final report.

DOT National Transportation Integrated Search

2016-10-01

The objective of this study was to determine the economic impact of designing pre-tensioned prestressed concrete beam (PPCB) : bridges utilizing the continuity developed in the bridge deck as opposed to the current Iowa Department of Transportation (...

Rapid construction of Pacific Street Bridge with o.7 inch strands.

DOT National Transportation Integrated Search

2010-10-01

The Pacific Street Bridge over I-680 in Omaha, NE is the first bridge in the United States to use 0.7-in.-diameter prestressing : strands in pretensioned concrete girders. This project was funded by FHWA through NDOR under the Innovative Bridge Resea...

Assessing the damage potential in pretensioned bridges caused by increased truck loads due to freight movements (phase II).

DOT National Transportation Integrated Search

2011-08-01

With aging and deterioration of bridges, evaluation of existing conditions of their structural elements becomes vital to : engineers and public officials when deciding how to repair or replace the structures. The ability to obtain necessary : informa...

Finite element analysis of contributing factors to the horizontal splitting cracks in concrete crossties pretensioned with seven-wire strands.

DOT National Transportation Integrated Search

2017-04-04

This paper employs the finite element (FE) modeling : method to investigate the contributing factors to the horizontal : splitting cracks observed in the upper strand plane in some : concrete crossties made with seven-wire strands. The concrete...

Long-term monitoring of a pretensioned concrete bridge near Winfield, Kansas.

DOT National Transportation Integrated Search

2016-10-01

The following report is an expansion of previous work conducted at Kansas State University and published as FHWA-KS-07-1 in April 2007 (Larson, Peterman, & Esmaeily, 2007). It details the findings from the long-term monitoring of a five-span bridge t...

40 CFR 16.10 - Penalties.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Penalties. 16.10 Section 16.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GENERAL IMPLEMENTATION OF PRIVACY ACT OF 1974 § 16... or obtains any record concerning an individual from an agency under false pretenses shall be guilty...

Finite element analysis of deep wide-flanged pre-stressed girders to understand and control end cracking : [work plan].

DOT National Transportation Integrated Search

2011-01-01

Project -- Work Approach: The first phase will examine the critical problem of controlling cracking in the 82W : girders. This complex problem is controlled by effects of concentrated stresses, force : transfer from pre-tensioning strand, inelastic b...

Fatigue and shear behavior of HPC bulb-tee girders: final report.

DOT National Transportation Integrated Search

2005-02-01

Five 96-ft. (29.3-m) long, 72-in. (1.83-m) deep, precast, pretensioned bulb-tee girders were tested to evaluate their behavior under flexural fatigue. Three of the girders were also tested to measure their static shear strength. One girder was tested...

Fatigue and shear behavior of HPC bulb-tee girders : interim report.

DOT National Transportation Integrated Search

2003-10-01

Three 96-ft (29.3-m) long, 72-in. (1.83-m) deep, precast, pretensioned bulb-tee girders were tested to evaluate behavior under flexural fatigue and static shear loadings. The three girders had a design concrete compressive strength of 10,000 psi (69....

Relations between Fantasy Orientation and Emotion Regulation in Preschool

ERIC Educational Resources Information Center

Gilpin, Ansley T.; Brown, Melissa M.; Pierucci, Jillian M.

2015-01-01

Research Findings: Emotion regulation is a strong predictor of both short- and long-term peer relationships and social competence and is often targeted in preschool curricula and interventions. Pretense is a natural activity of childhood that is thought to facilitate the development of socialization, perspective taking, language, and possibly…

32 CFR 700.828 - Search by foreign authorities.

Code of Federal Regulations, 2013 CFR

2013-07-01

... REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commanding Officer Commanding Officers in General § 700.828 Search by foreign authorities. (a) The commanding officer shall not permit a ship under his or her command to be searched on any pretense whatsoever by any person...

32 CFR 700.828 - Search by foreign authorities.

Code of Federal Regulations, 2012 CFR

2012-07-01

... REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commanding Officer Commanding Officers in General § 700.828 Search by foreign authorities. (a) The commanding officer shall not permit a ship under his or her command to be searched on any pretense whatsoever by any person...

32 CFR 700.828 - Search by foreign authorities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commanding Officer Commanding Officers in General § 700.828 Search by foreign authorities. (a) The commanding officer shall not permit a ship under his or her command to be searched on any pretense whatsoever by any person...

32 CFR 700.828 - Search by foreign authorities.

Code of Federal Regulations, 2010 CFR

2010-07-01

... REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commanding Officer Commanding Officers in General § 700.828 Search by foreign authorities. (a) The commanding officer shall not permit a ship under his or her command to be searched on any pretense whatsoever by any person...

32 CFR 700.828 - Search by foreign authorities.

Code of Federal Regulations, 2014 CFR

2014-07-01

... REGULATIONS AND OFFICIAL RECORDS UNITED STATES NAVY REGULATIONS AND OFFICIAL RECORDS The Commanding Officer Commanding Officers in General § 700.828 Search by foreign authorities. (a) The commanding officer shall not permit a ship under his or her command to be searched on any pretense whatsoever by any person...

Three Epiphanic Fragments: Education and the Essay in Memory

ERIC Educational Resources Information Center

Aldridge, David

2014-01-01

Pádraig Hogan has argued for a powerful conception of education as epiphany that is illuminated by the work of Heidegger and Joyce. But what are we to make of Stephen Dedalus' intention (pretension?) to "Remember your epiphanies"? Developing the phenomenological Erinnerungsversuch or "essay in memory" of David Farrell…

Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : tech transfer summary.

DOT National Transportation Integrated Search

2016-10-01

The objective of this study was to determine the economic impact of : designing pre-tensioned prestressed concrete beam (PPCB) bridges : utilizing the continuity developed in the bridge deck as opposed to the : current Iowa Department of Transportati...

Nation-States in Continental Markets: The Political Geography of Free Trade.

ERIC Educational Resources Information Center

Merrett, Christopher D.

1997-01-01

Argues that neoclassical conceptions of political geography separate economic from political processes and therefore ignore the consequences of economic policies. Uses discourse theory to show how the pretensions of objectivity embedded in neoclassical trade theory obscure these consequences. Briefly reviews trade theory from Adam Smith to the…

Toward Creativity: Do Theatrical Experiences Improve Pretend Play and Cooperation among Preschoolers?

ERIC Educational Resources Information Center

Rowe, Meredith L.; Salo, Virginia C.; Rubin, Kenneth

2018-01-01

The authors ask if participating in an early-childhood theater production improves pretend play and cooperation among preschoolers. They examined play sessions immediately before and after productions of interactive earlychildhood performances at Imagination Stage, Inc. and measured children's engagement, cooperation, pretense, and misbehavior.…

"A Community College with Ivory Tower Pretensions": Perceptions of a New University

ERIC Educational Resources Information Center

McKenzie, Sierra; King, Alyson E.

2016-01-01

The ways in which a new university, the University of Ontario Institute of Technology (UOIT), was represented in local, regional, and national newspapers highlight the difficulties of identity creation for organizations. Drawing on theories of organizational identity and supplemented by interviews with UOIT's founding members, a qualitative…

5 CFR 2504.18 - Penalties.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Administrative Personnel OFFICE OF ADMINISTRATION, EXECUTIVE OFFICE OF THE PRESIDENT PRIVACY ACT REGULATIONS... matter within the jurisdiction of any agency of the United States. Section (i)(3) of the Privacy Act (5 U... request or obtain any record concerning an individual under false pretenses. Sections (i) (1) and (2) or 5...

36 CFR 903.13 - Penalties.

Code of Federal Regulations, 2010 CFR

2010-07-01

....13 Parks, Forests, and Public Property PENNSYLVANIA AVENUE DEVELOPMENT CORPORATION PRIVACY ACT § 903.13 Penalties. The provision of 5 U.S.C. 552a(i), as added by section 3 of the Privacy Act, make it a... concerning an individual from an agency under false pretenses. Similar penalties attach for violations by...

Assessing the Damage Potential in Pretensioned Bridges Caused by Increased Truck Loads Due to Freight Movements (Phase 1)

DOT National Transportation Integrated Search

2010-05-01

When evaluating the condition of existing bridges determining in situ stresses in the members provides valuable information about the condition of the structures. In this study, a method of surface strain relief was investigated whereby the change in...

Long-term monitoring of a pretensioned concrete bridge near Winfield, Kansas : [technical summary].

DOT National Transportation Integrated Search

2016-10-01

The following report is an expansion of previous work conducted at Kansas State University and published as FHWA-KS-07-1 in April 2007 (Larson, Peterman, & Esmaeily, 2007). It details the findings from the long-term monitoring of a five-span bridge t...

Expelling God from the University

ERIC Educational Resources Information Center

French, David

2006-01-01

The college administrators, who push homosexual rights so vigorously, are confused. They routinely flout the law, abandoning any pretense of neutrality, by censuring organizations that do not embrace gays into their midst. Again and again they punish or expel individuals for whom certain behaviors remain perverse or sinful. David French represents…

The Importance of Being Earnest

ERIC Educational Resources Information Center

O'Brien, Tom

2007-01-01

In this article, the author opines that modernist and especially postmodernist irony has gone beyond its traditional satirical function of deflating falsehood and exposing pretense. Because of certain historical complexities, irony has evolved in such a way that it has become the enemy of genuine open-mindedness. Among some American intellectuals,…

Develop Strong and Serviceable Details for Precast, Prestressed Concrete Bent Cap Standards That Can Be Implemented on Everyday Bridge Construction Projects, Project Summary

DOT National Transportation Integrated Search

2018-01-01

Pretensioned bent caps are an attractive substructure component because they offer contractors an option for fabrication by prestressing plants and can be used to eliminate or reduce cracks. Two sets of design recommendations were developed to enable...

Pretense, Counterfactuals, and Bayesian Causal Models: Why What Is Not Real Really Matters

ERIC Educational Resources Information Center

Weisberg, Deena S.; Gopnik, Alison

2013-01-01

Young children spend a large portion of their time pretending about non-real situations. Why? We answer this question by using the framework of Bayesian causal models to argue that pretending and counterfactual reasoning engage the same component cognitive abilities: disengaging with current reality, making inferences about an alternative…

5 CFR 1630.18 - Penalties.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Administrative Personnel FEDERAL RETIREMENT THRIFT INVESTMENT BOARD PRIVACY ACT REGULATIONS § 1630.18 Penalties... jurisdiction of any agency of the United States. Section (i)(3) of the Privacy Act, 5 U.S.C. 552a(i)(3), makes... any record concerning an individual under false pretenses. Sections (i) (1) and (2) of 5 U.S.C. 552a...

1 CFR 455.11 - Penalties.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Provisions MISCELLANEOUS AGENCIES NATIONAL CAPITAL PLANNING COMMISSION (PRIVACY ACT REGULATIONS) § 455.11... jurisdiction of any agency of the United States. Section 552a(i)(3) of the Privacy Act (5 U.S.C. 552a(i)(3... obtain any record concerning an individual under false pretenses. Section 552a(i) (1) and (2) of the...

Meat goat kids finished on alfalfa, red clover, or orchardgrass pastures: Carcass merit and meat quality

USDA-ARS?s Scientific Manuscript database

This experiment was conducted in 2005-2007 to evaluate carcass and meat quality parameters when meat goat kids were finished on alfalfa (Medicago sativa L; ALF); red clover (Trifolium pretense L.; RCG); or orchardgrass (Dactylis glomerata L; OGR) pastures. Final shrunk body weights were similar whe...

How Fantasy Benefits Young Children's Understanding of Pretense

ERIC Educational Resources Information Center

Sobel, David M.

2006-01-01

Sobel and Lillard (2001 ) demonstrated that 4-year-olds' understanding of the role that the mind plays in pretending improved when children were asked questions in a fantasy context. The present study investigated whether this fantasy effect was motivated by children recognizing that fantasy contains violations of real-world causal structure. In…

75 FR 28557 - Pre-Stressed Concrete Steel Wire Strand from the People's Republic of China: Final Affirmative...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

...-stressed concrete (both pre-tensioned and post- tensioned) applications. The scope of this investigation... DEPARTMENT OF COMMERCE International Trade Administration [C-570-946] Pre-Stressed Concrete Steel... producers and exporters of pre-stressed concrete steel wire strand from the People's Republic of China (the...

Why Economists Are Part of the Problem

ERIC Educational Resources Information Center

Marglin, Stephen A.

2009-01-01

Economics is a two-faced discipline. It claims to be a science, describing the world without preconception or value judgment. The reality is that descriptive economics has been shaped by a framework of assumptions geared more to its normative message than to its pretensions. The self-interested individual--who rationally calculates how to achieve…

Signs of Pretense across Age and Scenario

ERIC Educational Resources Information Center

Lillard, Angeline; Nishida, Tracy; Massaro, Davide; Vaish, Amrisha; Ma, Lili; McRoberts, Gerald

2007-01-01

Participation in imagined worlds is a hallmark of the human species, and yet we know little about the context of its early emergence. The experiments reported here replicated and extended in 2 directions Lillard and Witherington's (2004) study of how mothers pretend to have snacks, across different ages of children (15- to 24-month-olds,…

Static Tensile and Transient Dynamic Response of Cracked Aluminum Plate Repaired with Composite Patch - Numerical Study

NASA Astrophysics Data System (ADS)

Khalili, S. M. R.; Shariyat, M.; Mokhtari, M.

2014-06-01

In this study, the central cracked aluminum plates repaired with two sided composite patches are investigated numerically for their response to static tensile and transient dynamic loadings. Contour integral method is used to define and evaluate the stress intensity factors at the crack tips. The reinforcement for the composite patches is carbon fibers. The effect of adhesive thickness and patch thickness and configuration in tensile loading case and pre-tension, pre-compression and crack length effect on the evolution of the mode I stress intensity factor (SIF) (KI) of the repaired structure under transient dynamic loading case are examined. The results indicated that KI of the central cracked plate is reduced by 1/10 to 1/2 as a result of the bonded composite patch repair in tensile loading case. The crack length and the pre-loads are more effective in repaired structure in transient dynamic loading case in which, the 100 N pre-compression reduces the maximum KI for about 40 %, and the 100 N pre-tension reduces the maximum KI after loading period, by about 196 %.

Pretending to Play or Playing to Pretend: The Case of Autism.

PubMed

Kasari, Connie; Chang, Ya-Chih; Patterson, Stephanie

2013-01-01

An article by Angeline S. Lillard and others published in the January 2013 issue of Psychological Bulletin about the impact of pretend play on child development raised a number of issues about play studies and child psychology. They claimed that, contrary to current theories on the subject, the evidence of many studies does not support causal explanations of play's relationship to most childhood development. In this article, authors Kasari, Chang, and Patterson review these arguments about play and devlopment in relation to children with autism-children who show specific deficits in pretend play. They argue that the study of these children provides a unique opportunity to consider which elements in play are important and how play skills are associated with different periods of child development. They conclude that, because pretend play requires intervention for the majority of children with autism, improving pretense in these children may shed more light on the causal impact of pretense on later developing skills in children. Key words: child development and pretend play; children with autism; funtional play; intervention in play; symbol play.

Dynamics of a passive micro-vibration isolator based on a pretensioned plane cable net structure and fluid damper

NASA Astrophysics Data System (ADS)

Chen, Yanhao; Lu, Qi; Jing, Bo; Zhang, Zhiyi

2016-09-01

This paper addresses dynamic modelling and experiments on a passive vibration isolator for application in the space environment. The isolator is composed of a pretensioned plane cable net structure and a fluid damper in parallel. Firstly, the frequency response function (FRF) of a single cable is analysed according to the string theory, and the FRF synthesis method is adopted to establish a dynamic model of the plane cable net structure. Secondly, the equivalent damping coefficient of the fluid damper is analysed. Thirdly, experiments are carried out to compare the plane cable net structure, the fluid damper and the vibration isolator formed by the net and the damper, respectively. It is shown that the plane cable net structure can achieve substantial vibration attenuation but has a great amplification at its resonance frequency due to the light damping of cables. The damping effect of fluid damper is acceptable without taking the poor carrying capacity into consideration. Compared to the plane cable net structure and the fluid damper, the isolator has an acceptable resonance amplification as well as vibration attenuation.

Distributed sensing signal analysis of deformable plate/membrane mirrors

NASA Astrophysics Data System (ADS)

Lu, Yifan; Yue, Honghao; Deng, Zongquan; Tzou, Hornsen

2017-11-01

Deformable optical mirrors usually play key roles in aerospace and optical structural systems applied to space telescopes, radars, solar collectors, communication antennas, etc. Limited by the payload capacity of current launch vehicles, the deformable mirrors should be lightweight and are generally made of ultra-thin plates or even membranes. These plate/membrane mirrors are susceptible to external excitations and this may lead to surface inaccuracy and jeopardize relevant working performance. In order to investigate the modal vibration characteristics of the mirror, a piezoelectric layer is fully laminated on its non-reflective side to serve as sensors. The piezoelectric layer is segmented into infinitesimal elements so that microscopic distributed sensing signals can be explored. In this paper, the deformable mirror is modeled as a pre-tensioned plate and membrane respectively and sensing signal distributions of the two models are compared. Different pre-tensioning forces are also applied to reveal the tension effects on the mode shape and sensing signals of the mirror. Analytical results in this study could be used as guideline of optimal sensor/actuator placement for deformable space mirrors.

Finite Element Analysis of Patient-Specific Mitral Valve with Mitral Regurgitation.

PubMed

Pham, Thuy; Kong, Fanwei; Martin, Caitlin; Wang, Qian; Primiano, Charles; McKay, Raymond; Elefteriades, John; Sun, Wei

2017-03-01

Functional mitral regurgitation (FMR) is a significant complication of left ventricular dysfunction and strongly associated with a poor prognosis. In this study, we developed a patient-specific finite element (FE) model of the mitral apparatus in a FMR patient which included: both leaflets with thickness, annulus, chordae tendineae, and chordae insertions on the leaflets and origins on the papillary muscles. The FE model incorporated human age- and gender-matched anisotropic hyperelastic material properties, and MV closure at systole was simulated. The model was validated by comparing the FE results from valve closure simulation with the in vivo geometry of the MV at systole. It was found that the FE model could not replicate the in vivo MV geometry without the application of tethering pre-tension force in the chordae at diastole. Upon applying the pre-tension force and performing model optimization by adjusting the chordal length, position, and leaflet length, a good agreement between the FE model and the in vivo model was established. Not only were the chordal forces high at both diastole and systole, but the tethering force on the anterior papillary muscle was higher than that of the posterior papillary muscle, which resulted in an asymmetrical gap with a larger orifice area at the anterolateral commissure resulting in MR. The analyses further show that high peak stress and strain were found at the chordal insertions where large chordal tethering forces were found. This study shows that the pre-tension tethering force plays an important role in accurately simulating the MV dynamics in this FMR patient, particularly in quantifying the degree of leaflet coaptation and stress distribution. Due to the complexity of the disease, the patient-specific computational modeling procedure of FMR patients presented should be further evaluated using a large patient cohort. However, this study provides useful insights into the MV biomechanics of a FMR patient, and could serve as a tool to assist in pre-operative planning for MV repair or replacement surgical or interventional procedures.

A planar shock isolation system with high-static-low-dynamic-stiffness characteristic based on cables

NASA Astrophysics Data System (ADS)

Ma, Yanhui; He, Minghua; Shen, Wenhou; Ren, Gexue

2015-12-01

In this paper, a simple and designable shock isolation system with ideal high-static-low-dynamic-stiffness (HSLDS) is proposed, which is intended for the horizontal plane shock isolation application. In this system, the isolated object is suspended by several bearing cables and constrained by a number of uniformly distributed pretensioned cables in the horizontal plane, where the low dynamic stiffness of the system is main controlled by the pretension of the planar cables, whilst the high static stiffness is determined by the axial stiffness of the planar cables and their geometric settings. To obtain the HSLDS characteristic of the system, a brief theoretical description of the relationship between the restoring force and displacement is derived. By obtaining the three-order Taylor expansion with sufficient accuracy of the restoring force, influence of planar cable parameters on the low dynamic and high static stiffness is thus given, therefore, the required HSLDS isolator can be easily designed by adjusting the planar cable length, pretension and tensile stiffness. Finally, the isotropy characteristic of the restoring force of the system with different numbers of planar cables is investigated. To evaluate the performance of the system, a rigid isolated object and flexible cables coupling simulation model considering the contacts of the system is established by using multibody dynamics approach. In this model, flexible cables are simulated by 3-node cable element based on the absolute nodal coordinate formulation; the contact between cable and isolated object is simulated based on Hertz contact theory. Finally, the time-domain shock excitation is converted from the design shock spectrum on the basis of BV043/85 criterion. The design procedure of this isolator and some useful guidelines for choosing cable parameters are presented. In addition, a summary about the performance of the isolators with different numbers of cables shocking in an arbitrary direction is given in the conclusion.

I Saw the "Real" Father Christmas! Children's Everyday Uses of the Words "Real", "Really", and "Pretend"

ERIC Educational Resources Information Center

Bunce, Louise; Harris, Margaret

2008-01-01

The words "real", "really" and "pretend" are used in developmental research paradigms to reflect both the notions of 'authenticity' (in pretense-reality and appearance-reality research) and 'existence' (in fantasy-reality research). The current study explored whether children also expressed these notions in their everyday uses of "real", "really",…

"This Is a Bad Dog, You Know...": Constructing Shared Meanings During Sibling Pretend Play

ERIC Educational Resources Information Center

Howe, Nina; Petrakos, Hariclia; Rinaldi, Christina M.; LeFebvre, Rachel

2005-01-01

The construction of shared meanings in play, pretense enactment, internal state language, and sibling relationship quality were investigated in 40 kindergarteners with an older (M age = 7.10 years) or younger (M age = 3.6 years) sibling. Dyadic strategies to construct shared meanings (e.g., extensions, building on) were positively associated with…

Two-Year-Olds Grasp the Intentional Structure of Pretense Acts

ERIC Educational Resources Information Center

Rakoczy, Hannes; Tomasello, Michael

2006-01-01

Twenty-two- and 27-month-old children were tested for their understanding of pretending as a specific intentional action form. Pairs of superficially similar behaviors--pretending to perform an action and trying to perform that action--were demonstrated to children. The 27-month-olds, and to some degree the 22-month-olds, showed in their responses…

The Committee for Cultural Freedom and the Roots of McCarthyism

ERIC Educational Resources Information Center

Bullert, Gary B.

2013-01-01

Among the most controversial aspects of John Dewey's career as a public intellectual was his conflict with the Communist Party and its various front groups. John Dewey and Sidney Hook co-founded the Committee for Cultural Freedom that directly exposed that pretense of the Popular Front, which excluded the Soviet Union from the list of totalitarian…

Pseudoscience and Mental Ability: The Origins and Fallacies of the IQ Controversy.

ERIC Educational Resources Information Center

Blum, Jeffrey M.

Pseudoscience, or the process of persuasion by establishing a pretense of scientific discovery, is examined in this book in an effort to dispel false notions about the validity of various measures of intelligence and the correlations of genetics to mental ability. The history and development of concepts related to hereditary intelligence and…

Brief Report: Difficulty in Understanding Social Acting (But Not False Beliefs) Mediates the Link between Autistic Traits and Ingroup Relationships

ERIC Educational Resources Information Center

Yang, Daniel Y.-J.; Baillargeon, Renée

2013-01-01

Why do individuals with more autistic traits experience social difficulties? Here we examined the hypothesis that these difficulties stem in part from a challenge in understanding social acting, the prosocial pretense that adults routinely produce to maintain positive relationships with their ingroup. In Study 1, we developed a self-administered…

The Development of Representational Play in Chimpanzees and Bonobos: Evolutionary Implications, Pretense, and the Role of Interspecies Communication

ERIC Educational Resources Information Center

Lyn, Heidi; Greenfield, Patricia; Savage-Rumbaugh, Sue

2006-01-01

This research investigates the development of symbolic or representational play in two species of the genus "Pan", bonobos ("Pan paniscus") and chimpanzees ("Pan troglodytes"). The participants varied not only by species, but also as to whether they had become proficient in communicating with humans via a set of arbitrary visual symbols, called…

Promoting Narrative Competence through Adult-Child Joint Pretense: Lessons from the Scandinavian Educational Practice of Playworld

ERIC Educational Resources Information Center

Baumer, Sonja; Ferholt, Beth; Lecusay, Robert

2005-01-01

This paper examines the effects of the playworld educational practice on the development of narrative competence in 5- to 7-year-old children. The playworld educational practice is derived from play pedagogy and the theory of narrative learning, both developed and implemented in Scandinavia. The playworld practice consists of joint adult-child…

Study on parameters affecting the mechanical properties of dry fiber bundles during continuous composite manufacturing processes

NASA Astrophysics Data System (ADS)

Maier, A.; Schledjewski, R.

2016-07-01

For continuous manufacturing processes mechanical preloading of the fibers occurs during the delivery of the fibers from the spool creel to the actual manufacturing process step. Moreover preloading of the dry roving bundles might be mandatory, e.g. during winding, to be able to produce high quality components. On the one hand too high tensile loads within dry roving bundles might result in a catastrophic failure and on the other hand the part produced under too low pre-tension might have low quality and mechanical properties. In this work, load conditions influencing mechanical properties of dry glass fiber bundles during continuous composite manufacturing processes were analyzed. Load conditions, i.e. fiber delivery speed, necessary pre-tension and other effects of the delivery system during continuous fiber winding, were chosen in process typical ranges. First, the strain rate dependency under static tensile load conditions was investigated. Furthermore different free gauge lengths up to 1.2 m, interactions between fiber points of contact regarding influence of sizing as well as impregnation were tested and the effect of twisting on the mechanical behavior of dry glass fiber bundles during the fiber delivery was studied.

Analysis of alternatives for using cable bolts as primary support at two low-seam coal mines

PubMed Central

Esterhuizen, Gabriel S.; Tulu, Ihsan B.

2016-01-01

Cable bolts are sometimes used in low-seam coal mines to provide support in difficult ground conditions. This paper describes cable bolting solutions at two low-seam coal mines in similar ground conditions. Both mines used support systems incorporating cable bolts as part of the primary support system. Two original cable bolt based support systems as well as two modified systems are evaluated to estimate their ability to prevent large roof falls. One of the support systems incorporated passive cable bolts, while the other used pre-tensioned cable bolts. The results and experience at the mines showed that the modified systems provided improved stability over the original support systems. The presence of the cable bolts is the most important contribution to stability against large roof falls, rather than the details of the support pattern. It was also found that a heavy steel channel can improve the safety of the system because of the ‘sling’ action it provides. Additionally, the analysis showed that fully-grouted rebar bolts load much earlier than the cable bolts, and pre-tensioning of the cable bolts can result in a more uniform distribution of loading in the roof. PMID:27722019

Dynamic and thermal response finite element models of multi-body space structural configurations

NASA Technical Reports Server (NTRS)

Edighoffer, Harold H.

1987-01-01

Presented is structural dynamics modeling of two multibody space structural configurations. The first configuration is a generic space station model of a cylindrical habitation module, two solar array panels, radiator panel, and central connecting tube. The second is a 15-m hoop-column antenna. Discussed is the special joint elimination sequence used for these large finite element models, so that eigenvalues could be extracted. The generic space station model aided test configuration design and analysis/test data correlation. The model consisted of six finite element models, one of each substructure and one of all substructures as a system. Static analysis and tests at the substructure level fine-tuned the finite element models. The 15-m hoop-column antenna is a truss column and structural ring interconnected with tension stabilizing cables. To the cables, pretensioned mesh membrane elements were attached to form four parabolic shaped antennae, one per quadrant. Imposing thermal preloads in the cables and mesh elements produced pretension in the finite element model. Thermal preload variation in the 96 control cables was adjusted to maintain antenna shape within the required tolerance and to give pointing accuracy.

[Allelopathic effects of invasive weed Solidago canadensis on native plants].

PubMed

Mei, Lingxiao; Chen, Xin; Tang, Jianjun

2005-12-01

With growth chamber method, this paper studied the allelopathic potential of invasive weed Solidago canadensis on native plant species. Different concentration S. canadensis root and rhizome extracts were examined, and the test plants were Trifolium repens, Trifolium pretense, Medicago lupulina, Lolium perenne, Suaeda glauca, Plantago virginica, Kummerowia stipulacea, Festuca arundinacea, Ageratum conyzoides, Portulaca oleracea, and Amaranthus spinosus. The results showed that the allelopathic inhibitory effect of the extracts from both S. canadensis root and rhizome was enhanced with increasing concentration, and rhizome extracts had a higher effect than root extracts. At the lowest concentration (1:60), root extract had little effect on the seed germination and seedling growth of T. repens, but rhizome extract could inhibit the germination of all test plants though the inhibitory effect varied with different species. The inhibition was the greatest for grass, followed by forb and legume. 1:60 (m:m) rhizome extract had similar effects on seed germination and radicel growth, but for outgrowth, the extract could inhibit Kummerowia stipulacea, Amaranthus spinosus and Festuca arundinacea, had no significant impact on Lolium perenne, Plantago virginica, Ageratum conyzoides, Portulaca oleracea and Amaranthus spinosus, and stimulated Trifolium repens, Trifolium pretense and Medicago lupulina.

Pretense and Possibility--A Theoretical Proposal about the Effects of Pretend Play on Development: Comment on Lillard et al. (2013)

ERIC Educational Resources Information Center

Walker, Caren M.; Gopnik, Alison

2013-01-01

The review by Lillard et al. (2013) highlighted the need for additional research to better clarify the nature of the relationship between pretend play and development. However, the authors did not provide a proposal for how to structure the direction of this future work. Here, we provide a possible framework for generating additional research.…

Embodying Pre-Tense Conditions for Research among Teacher Educators in the Australian University Sector: A Bourdieusian Analysis of Ethico-Emotive Suffering

ERIC Educational Resources Information Center

Zipin, Lew; Nuttall, Joce

2016-01-01

Interviews conducted as part of the Work of Teacher Education (WoTE) project in Australia highlight emotional and ethical suffering embodied by teacher educators who find their research aspirations thwarted in the context of high-stakes research assessment exercises. We argue that government-run assessments, such as Excellence in Research for…

What Makes a Fiat Run? A Consideration of the Nature of Fiat Power in Academic Policy Deliberation.

ERIC Educational Resources Information Center

Fadely, Dean

In the game-like world of competitive tournament debating, fiat power is simply another rule of the game, a way of saying "hypothetically" or "for the sake of argument let us assume this affirmative plan to be implemented." While fiat power is just a way of saying "let's pretend," there are limits to the pretense. For…

Fatigue Response of Pretensioned Concrete Beams

DTIC Science & Technology

2003-08-01

Dedication To my beautiful wife and children, whose love and support motivate my life’s endeavors. Acknowledgements I first offer appreciation to the Texas...7,058,000 Straight PS3 27.6 2,069,000 Straight PS4 27.6 4,173,000 Straight VP2 36.3 1,510,000 Straight VP3 27.6 2,926,000 Straight VP4 27.6 2,890,000 Straight

A displacement-based approach for determining non-linear effects on pre-tensioned-cable cross-braced structures

NASA Astrophysics Data System (ADS)

Giaccu, Gian Felice; Caracoglia, Luca

2017-04-01

Pre-tensioned-cable bracing systems are widely employed in structural engineering to limit lateral deflections and stabilize structures. A suitable configuration of the pre-tensioned-cable bracing systems in a structure is an important issue since the internal force distribution, emerging from the interaction with the existing structure, significantly affects the structural dynamic behavior. The design, however, is often based on the intuition and the previous experience of the engineer. In recent years, the authors have been investigating the non-linear dynamic response of cable systems, installed on cable-stayed bridges, and in particular the so-called "cable-cross-tie systems" forming a cable network. The bracing cables (cross-ties) can exhibit slackening or snapping. Therefore, a non-linear unilateral model, combined with the taut-cable theory, is required to simulate the incipient slackening conditions in the stays. Capitalizing from this work on non-linear cable dynamics, this paper proposes a new approach to analyze, in laterally- braced truss structures, the unilateral effects and dynamic response accounting for the loss in the pre-tensioning force imparted to the bracing cables. This effect leads to non-linear vibration of the structure. In this preliminary study, the free vibrations of the structure are investigated by using the "Equivalent Linearization Method". A performance coefficient, a real positive number between 0.5 and 1.0, is defined and employed to monitor the relative reduction in the apparent stiffness of the braces during structural vibration, "mode by mode". It is shown that the system can exhibit alternate unilateral behavior of the cross-braces. A reduction of the performance coefficient close to fifty percent is observed in the braces when the initial pre-tensioning force is small. On the other hand the performance coefficient tends to one in the case of a high level of pre-stress. It is concluded that the performance coefficient may possibly be used as an indicator for the design of the braces since a suitable selection of the initial pre-tensioning force can avoid slackening in the braces.

"Mommy, You Are the Princess and I Am the Queen": How Preschool Children's Initiation and Language Use during Pretend Play Relate to Complexity

ERIC Educational Resources Information Center

Melzer, Dawn K.; Palermo, Cori A.

2016-01-01

The present study investigated the relationship between complexity of pretend play, initiation of pretense activities, and mental state utterances used during play. Children 3 to 4 years of age were videotaped while engaging in pretend play with a parent. The videotapes were coded according to mental state utterances (i.e. desire, emotion,…

Colombia’s Bold Gamble for Peace,

DTIC Science & Technology

1985-02-01

well-trained in the art of 0 negotiations, familiar with every technique, able to cut off almost every avenue of maneuver and maintain the...refer to simply as La Violencia (The Violence), a period of bitter internecine political warfare that had left 200,000 persons dead since 1948. In 1958...reject this amnesty, they lose all political pretensions. They show themselves to be traficantes do violencia (traffickers of violence) who, like

A comparison between a child-size PMHS and the Hybrid III 6 YO in a sled frontal impact.

PubMed

Lopez-Valdes, Francisco J; Forman, Jason; Kent, Richard; Bostrom, Ola; Segui-Gomez, Maria

2009-10-01

As pediatric PMHS data are extremely limited, evidence of kinematic differences between pediatric ATDs and live humans comes from comparison of laboratory data to field crash data. Despite the existence of regulations intended to prevent head injuries, these remain the most common serious injuries sustained by children in crashes. In this study, nine frontal sled tests using a Hybrid III 6YO and three tests performed with a child-size adult PMHS were compared, with focus on the kinematic responses (especially of the head) and the seatbelt forces generated during the impact. Two different restraint systems (a pretensioning, force-limiting seatbelt, and a non pretensioning force-limiting standard belt) and two different impact speeds (29 km/h and 48 km/h) were compared. Data from the PMHS were scaled using the erect sitting height of a 50th percentile 6YO and both scaled and unscaled data are presented. The ATD predicted correctly the peak values of the scaled displacements of the PMHS, but differences in relevant parameters such as torso angle and resultant acceleration at different locations were found between the dummy and the PMHS. The ATD's stiffer thoracic spine is hypothesized as a major cause of these differences.

Fluid-Structure interaction analysis and performance evaluation of a membrane blade

NASA Astrophysics Data System (ADS)

Saeedi, M.; Wüchner, R.; Bletzinger, K.-U.

2016-09-01

Examining the potential of a membrane blade concept is the goal of the current work. In the sailwing concept the surface of the wing, or the blade in this case, is made from pre-tensioned membranes which meet at the pre-tensioned edge cable at the trailing edge. Because of the dependency between membrane deformation and applied aerodynamic load, two-way coupled fluid-structure interaction analysis is necessary for evaluation of the aerodynamic performance of such a configuration. The in-house finite element based structural solver, CARAT++, is coupled with OpenFOAM in order to tackle the multi-physics problem. The main aerodynamic characteristics of the membrane blade including lift coefficient, drag coefficient and lift to drag ratio are compared with its rigid counterpart. A single non-rotating NREL phase VI blade is studied here as a first step towards analyzing the concept for the rotating case. Compared with the rigid blade, the membrane blade has a higher slope of the lift curve. For higher angles of attack, lift and drag coefficients as well as the lift to drag ratio is higher for the membrane blade. A single non-rotating blade is studied here as a first step towards analyzing the concept for the rotating case.

"No! The lambs can stay out because they got cozies": constructive and destructive sibling conflict, pretend play, and social understanding.

PubMed

Howe, Nina; Rinaldi, Christina M; Jennings, Melissa; Petrakos, Harriet

2002-01-01

Associations among constructive and destructive sibling conflict, pretend play, internal state language, and sibling relationship quality were investigated in 40 middle-class dyads with a kindergarten-age child (M age = 5.7 years). In 20 dyads the sibling was older (M age = 7.1 years) and in 20 dyads the sibling was younger (M age = 3.6 years). Dyads were videotaped playing with a farm set for 15 min; transcribed sessions were coded for (1) five types of conflict issues; (2) constructive, destructive, and passive resolution strategies; and (3) verbal and physical aggression. Measures of pretend play enactment, low- and high-level pretense negotiation strategies, and internal state language were also based on the transcripts. The Sibling Behavior and Feelings Questionnaire was used to assess both siblings' perceptions of sibling relationship quality. Findings revealed that conflict issues, aggression, and internal state language were associated with specific resolution strategies. Associations were evident between conflict issues and resolutions. Moreover, conflict issues and resolutions were associated with (1) relationship quality, (2) high-level pretense negotiation, and (3) internal state language employed in both play and conflict. Findings are discussed in light of recent theory on developmental processes operating within children's relationships.

TIMING APPARATUS

DOEpatents

Bennett, A.E.; Geisow, J.C.H.

1956-04-17

The timing device comprises an escapement wheel and pallet, a spring drive to rotate the escapement wheel to a zero position, means to wind the pretensioned spring proportional to the desired signal time, and a cam mechanism to control an electrical signal switch by energizing the switch when the spring has been wound to the desired position, and deenergizing it when it reaches the zero position. This device produces an accurately timed signal variably witain the control of the operator.

Moving Beyond Pretense: Nuclear Power and Nonproliferation

DTIC Science & Technology

2014-06-01

and Hezbollah, might be at a heightened risk of transfer- ring nuclear weapons to terrorists. Moreover, even if no state would ever intentionally...programs—basically IAEA inspections and ex- port controls—we seem to be slipping into reliance on greatly increased national intelligence operations, both...generators, turbine , piping, and other large equipment needed for the system. • By 2008: A total of 82 megatons of fuel enriched up to 3.62 percent U

Islam: Ideology and Conflict

DTIC Science & Technology

2014-12-01

layers of Islam that Dr. Barrett peels back to reveal the pretense that is the idea of Islam as an ideology. The central theme of this monograph is that...doctrine of man.”11 As Hasan al- Banna , the founder of the Muslim Brotherhood, put it: “the social principles” of the West converted man into an...Hasan al- Banna , “New Renaissance: The Viewpoint of the Muslim Brotherhood” in Political and Social Thought in the Contemporary Middle East by Kamal H

Precise low cost chain gears for heliostats

NASA Astrophysics Data System (ADS)

Liedke, Phillip; Lewandowski, Arkadiusz; Pfahl, Andreas; Hölle, Erwin

2016-05-01

This work investigates the potential of chain gears as precise and low cost driving systems for rim drive heliostats. After explaining chain gear basics the polygon effect and chain lengthening are investigated. The polygon effect could be measured by a heliostat with chain rim gear and the chain lengthening with an accordant test set up. Two gear stages are scope of this work: a rim gear and an intermediate gear. Dimensioning, pretensioning and designing for both stages are explained.

Effects of cold-treatment and strain-rate on mechanical properties of NbTi/Cu superconducting composite wires.

PubMed

Guan, Mingzhi; Wang, Xingzhe; Zhou, Youhe

2015-01-01

During design and winding of superconducting magnets at room temperature, a pre-tension under different rate is always applied to improve the mechanical stability of the magnets. However, an inconsistency rises for superconductors usually being sensitive to strain and oversized pre-stress which results in degradation of the superconducting composites' critical performance at low temperature. The present study focused on the effects of the cold-treatment and strain-rate of tension deformation on mechanical properties of NbTi/Cu superconducting composite wires. The samples were immersed in a liquid nitrogen (LN2) cryostat for the adiabatic cold-treatment, respectively with 18-hour, 20-hour, 22-hour and 24-hour. A universal testing machine was utilized for tension tests of the NbTi/Cu superconducting composite wires at room temperature; a small-scale extensometer was used to measure strain of samples with variable strain-rate. The strength, elongation at fracture and yield strength of pre-cold-treatment NbTi/Cu composite wires were drawn. It was shown that, the mechanical properties of the superconducting wires are linearly dependent on the holding time of cold-treatment at lower tensile strain-rate, while they exhibit notable nonlinear features at higher strain-rate. The cold-treatment in advance and the strain-rate of pre-tension demonstrate remarkable influences on the mechanical property of the superconducting composite wires.

Deployment and retraction of a cable-driven solar array: Testing and simulation

NASA Technical Reports Server (NTRS)

Kumar, P.; Pellegrino, S.

1995-01-01

The paper investigates three critical areas in cable-driven rigid-panel solar arrays: First, the variation of deployment and retraction cable tensions due to friction at the hinges; Second, the change in deployment dynamics associated with different deployment histories; Third, the relationship between the level of pre-tension in the closed contact loops and the synchronization of deployment. A small scale model array has been made and tested, and its behavior has been compared to numerical simulations.

Department of Defense Law of War Manual (June 2015, Updated December 2016)

DTIC Science & Technology

2016-12-13

endeavours to obtain information in the zone of operations of a belligerent, with the intention of communicating it to the hostile party.”); LIEBER CODE art...88 (“ A spy is a person who secretly, in disguise or under false pretense, seeks information with the intention of communicating it to the enemy...4.17.2.4 With the Intention of Communicating It to the Hostile Party. A person must act with the intention of communicating the sought-after information to

Demonstration of a Wire Suspension for Virtual Flight Testing in a Wind Tunnel

DTIC Science & Technology

2009-02-01

They were connected by the roll shaft, which rotates in a pair of bearings. These bearings supported both radial and axial loads . Loads were...an axial load , and a radial ball bearing to support the radial loads . To determine whether the anticipated bearing friction is acceptable, we modeled... axial load due to cable pre-tension. Analysis showed that the best choice of pitch bearings is a combin- ation of a ball thrust bearing, which will carry

Biomechanical Properties of a Novel Biodegradable Magnesium-Based Interference Screw

PubMed Central

Ezechieli, Marco; Meyer, Hanna; Lucas, Arne; Helmecke, Patrick; Becher, Christoph; Calliess, Tilman; Windhagen, Henning; Ettinger, Max

2016-01-01

Magnesium-based interference screws may be an alternative in anterior/posterior cruciate ligament reconstruction. The well-known osteoconductive effects of biodegradable magnesium alloys may be useful. It was the purpose of this study to evaluate the biomechanical properties of a magnesium based interference screw and compare it to a standard implant. A MgYREZr-alloy interference screw and a standard implant (Milagro®; De Puy Mitek, Raynham, MA, USA) were used for graft fixation. Specimens were placed into a tensile loading fixation of a servohydraulic testing machine. Biomechanical analysis included pretensioning of the constructs at 20 N for 1 min following cyclic pretensioning of 20 cycles between 20 and 60 N. Biomechanical elongation was evaluated with cyclic loading of 1000 cycles between 50 and 200 N at 0.5 Hz. Maximum load to failure was 511.3±66.5 N for the Milagro® screw and 529.0±63.3 N for magnesium-based screw (ns, P=0.57). Elongations after preload, during cyclical loading and during failure load were not different between the groups (ns, P>0.05). Stiffness was 121.1±13.8 N/mm for the magnesium-based screw and 144.1±18.4 for the Milagro® screw (ns, P=0.32). MgYREZr alloy interference screws show comparable results in biomechanical testing to standard implants and may be an alternative for anterior cruciate reconstruction in the future. PMID:27433303

Mechanics of the taper integrated screwed-in (TIS) abutments used in dental implants.

PubMed

Bozkaya, Dinçer; Müftü, Sinan

2005-01-01

The tapered implant-abutment interface is becoming more popular due to the mechanical reliability of retention it provides. Consequently, understanding the mechanical properties of the tapered interface with or without a screw at the bottom has been the subject of a considerable amount of studies involving experiments and finite element (FE) analysis. This paper focuses on the tapered implant-abutment interface with a screw integrated at the bottom of the abutment. The tightening and loosening torques are the main factors in determining the reliability and the stability of the attachment. Analytical formulas are developed to predict tightening and loosening torque values by combining the equations related to the tapered interface with screw mechanics equations. This enables the identification of the effects of the parameters such as friction, geometric properties of the screw, the taper angle, and the elastic properties of the materials on the mechanics of the system. In particular, a relation between the tightening torque and the screw pretension is identified. It was shown that the loosening torque is smaller than the tightening torque for typical values of the parameters. Most of the tightening load is carried by the tapered section of the abutment, and in certain combinations of the parameters the pretension in the screw may become zero. The calculations performed to determine the loosening torque as a percentage of tightening torque resulted in the range 85-137%, depending on the values of taper angle and the friction coefficient.

Effects of fiber pre-strain on the healing efficiency of thermoset polymers

NASA Astrophysics Data System (ADS)

Ajisafe, Oludayo

One major challenge that has been facing material self healing is how to heal bigger macroscopic or structural scale damage autonomously, repeatedly, efficiently and at molecular length scale. Different approaches have been used to heal materials. However, none of them can heal macroscopic cracks. Our research group has proposed a novel shape-memory polymer (SMP) based, bio-inspired Close-Then-Heal (CTH) scheme to heal macroscopic cracks in SMP matrix. The most recent development in our group is to use SMP fibers to heal conventional thermosetting polymers according to the CTH scheme. The aim of this study is to further investigate the effect of pre-tension of SMP fibers during the cold-drawing programming on the self-healing efficiency of the conventional thermosetting polymer composites. This was done by fabricating a composite with thermoplastic particles (polycaprolactone) dispersed in a thermosetting polymer matrix (Epon 828). Shape memory fiber pre-tensioned into 3 different groups of 0%, 50% and 100% prestrain, was also embedded into the composite in the longitudinal direction. In this composite, the shape memory effect of the shape memory fibers is utilized for sealing (closing) the cracks and the thermoplastic particles are used for molecular-length scale healing. In this study, 7% by volume of thermoplastic particles was used. Beam specimens were prepared and controlled structural length scale damage was created prior to curing by inserting an aluminum foil of designed thickness in a perpendicular direction to the shape memory fibers before the matrix was allowed to cure. The aluminum sheet was removed post cure to leave a controlled damage. The specimen was healed by fixing the two ends of the beam and heating the sample above the Tg of the shape memory fiber. The recovery force of the sample was recorded and then the beam was tested again to fracture. This fracture healing cycle lasted 7 times. The healing efficiency was evaluated per the peak-tensile load. The Ultrasonic C-scan and SEM were used to examine the healed cracks. It was found that the beams with 100% pre-strained fiber were able to recover repeatedly about 50% of its peak tensile strength; the beams with 50% pre-strained fiber, 43%; and the beams with un-stretched fibers were able to recover about 21% of its original peak tensile strength. Also it was found that the higher the pre-tension the higher the recovery stress seen during the healing cycle.

Introduction to SQL. Ch. 1

NASA Technical Reports Server (NTRS)

McGlynn, T.; Santisteban, M.

2007-01-01

This chapter provides a very brief introduction to the Structured Query Language (SQL) for getting information from relational databases. We make no pretense that this is a complete or comprehensive discussion of SQL. There are many aspects of the language the will be completely ignored in the presentation. The goal here is to provide enough background so that users understand the basic concepts involved in building and using relational databases. We also go through the steps involved in building a particular astronomical database used in some of the other presentations in this volume.

Thermoelectric generator having a resiliently mounted removable thermoelectric module

DOEpatents

Purdy, David L.; Shapiro, Zalman M.; Hursen, Thomas F.; Maurer, Gerould W.

1976-11-02

An electrical generator having an Isotopic Heat Capsule including radioactive fuel rod 21 as a primary heat source and Thermoelectric Modules 41 and 43 as converters. The Biological Shield for the Capsule is suspended from Spiders at each end each consisting of pretensioned rods 237 and 239 defining planes at right angles to each other. The Modules are mounted in cups 171 of transition members 173 of a heat rejection Fin Assembly whose fins 195 and 197 extend from both sides of the transition member 173 for effective cooling.

Tests for Determining Failure Criteria of Ceramics under Ballistic Impact

DTIC Science & Technology

1992-06-01

strength steel rods, joined together by connectors and pretensioned to remove the slack before prcssurization. The system was designed to operate up...and ftaporta, IJIi J—arfW P*ii Kqfrwar. tv«a 11Q4. Arlington. VA 22201-4)02. an« t« «ha Oflna a« Manag *«** and Rudoat. f«*v«t HatfudtOA rVotoc«(0704-01...different mechanisms for failure and postfailure flow, and these mechanisms operate at different threshold loads. Two one-dimensional computational

Membrane Vibration Tests Using Surface-Bonded Piezoelectric Patch Actuation

NASA Technical Reports Server (NTRS)

Gasper, James L.; Pappa, Richard S.

2003-01-01

This paper describes the status of on-going work at the NASA Langley Research Center to measure the dynamics of thin membranes. The test article is a one-meter square pre-tensioned Kapton membrane that incorporates small surface-bonded piezoelectric patches strategically positioned to excite many modes. It is shown that PVDF (polyvinylidene fluoride) and MFC (macro fiber composite) piezoelectric patch actuators provide adequate excitation energy to obtain modal frequencies and mode shapes. Results from modal tests performed on the membrane using piezoelectric patches of different sizes and positions are discussed.

Structural Applications of Fibre Reinforced Concrete in the Czech Republic

NASA Astrophysics Data System (ADS)

Kohoutková, A.; Broukalová, I.

2017-09-01

The paper presents improvement of function and performance of the precast structural members by using fibre reinforced concrete (FRC) instead of ordinary reinforced concrete and attempts to transfer innovative technologies from laboratory in academic sphere into real industrial production which is cost-effective and brings about savings of labour and material. Three examples of successful technology transfer are shown - application of FRC in an element without common rebar reinforcement, in the element with steel rebar reinforcement and SFRC pre-tensioned structural element. Benefits of FRC utilization are discussed.

Wave propagation as a marker of structural and topographic properties of human skin

NASA Astrophysics Data System (ADS)

Djaghloul, M.; Abdouni, A.; Thieulin, C.; Zahouani, H.

2018-06-01

Chronological skin ageing is a phenomenon which imposes structural and functional changes on the cutaneous tissue. Mechanically, these changes can be related to structural rearrangements of the cutaneous tissue on surface and in volume (layers thickness). At the micro-structural level, the constitutional elements of the skin, collagen and elastin fibres, undergo also this rearrangement. The evolution of skin’s mechanical properties at this level is the origin of a primordial in-vivo mechanical characteristic known as the natural pretension. In the context of understanding the in-vivo skin mechanical behaviour, related to the natural pretension, a lot of instrumentations have been demonstrated in the literature. They are mainly based on the interaction between dynamic adapted solicitation and the observed reaction on the skin. In this study, we evaluate the mechanical behaviour of human skin, following an impact which induces wave propagation. The use of impact solicitation allows the direct correlation between the dynamic induced reaction (vibration, and wave propagation) of the cutaneous tissue and its mechanical property. In our development, impact solicitation is contactless, with an air blast as generator of local deformation. The estimation of the speed of wave propagation enables the characterization of the mechanical behaviour of the skin. In order to validate the developed approaches, to understand the chronological ageing, gender and anisotropy effects on the skin properties, measurements have been realized on 77 healthy volunteers separated in five age groups. The obtained results are consistent with earlier works and confirm the efficiency of the developed instrumentation to estimate the changes of mechanical behaviour of the skin under age and gender effects.

Nano-ADEPT Aeroloads Wind Tunnel Test

NASA Technical Reports Server (NTRS)

Smith, Brandon; Yount, Bryan; Kruger, Carl; Brivkalns, Chad; Makino, Alberto; Cassell, Alan; Zarchi, Kerry; McDaniel, Ryan; Ross, James; Wercinski, Paul;

Elastic properties of suspended black phosphorus nanosheets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Jia-Ying; Li, Yang; Zhen, Liang

2016-01-04

The mechanical properties of black phosphorus (BP) nanosheets suspended over circular holes were measured by an atomic force microscope nanoindentation method. The continuum mechanic model was introduced to calculate the elastic modulus and pretension of BP nanosheets with thicknesses ranging from 14.3 to 34 nm. Elastic modulus of BP nanosheets declines with thickness, and the maximum value is 276 ± 32.4 GPa. Besides, the effective strain of BP ranges from 8 to 17% with a breaking strength of 25 GPa. Our results show that BP nanosheets serve as a promising candidate for flexible electronic applications.

Large deflection analysis of a pre-stressed annular plate with a rigid boss under axisymmetric loading

NASA Astrophysics Data System (ADS)

Su, Y. H.; Chen, K. S.; Roberts, D. C.; Spearing, S. M.

2001-11-01

The large deflection analysis of a pre-stressed annular plate with a central rigid boss subjected to axisymmetric loading is presented. The factors affecting the transition from plate behaviour to membrane behaviour (e.g. thickness, in-plane tension and material properties) are studied. The effect of boss size and pre-tension on the effective stiffness of the plate are investigated. The extent of the bending boundary layers at the edges of the plate are quantified. All results are presented in non-dimensional form. The design implications for microelectromechanical system components are assessed.

Greek mathematical astronomy reconsidered

NASA Astrophysics Data System (ADS)

Thurston, Hugh

2002-03-01

Recent investigations have thrown new light on such topics as the early Greek belief in heliocentricity, the relation between Greek and Babylonian astronomy, the reliability of Ptolemy's Syntaxis, Hipparchus's theory of motion for the sun, Hipparchus's value for the obliquity of the ecliptic, and Eratosthenes' estimate of the size of the earth. Some claims resulting from these investigations are controversial, especially the reevaluation of Ptolemy (though it is notable that no one any longer uses data from the Syntaxis for investigating such things as the spin of the earth). This essay presents the evidence for these claims; it makes no pretense of presenting the evidence against them.

Feasibility study of applying an advanced composite structure technique to the fabrication of helicopter rotor blades

NASA Technical Reports Server (NTRS)

Gleich, D.

1972-01-01

The fabrication of helicopter rotary wings from composite materials is discussed. Two composite spar specimens consisting of compressively prestressed stainless steel liner over-wrapped with pretensioned fiberglass were constructed. High liner strength and toughness together with the prescribed prestresses and final sizing of the part are achieved by means of cryogenic stretch forming of the fiber wrapped composite spar at minus 320 F, followed by release of the forming pressure and warm up to room temperature. The prestresses are chosen to provide residual compression in the metal liner under operating loads.

Fabrication and testing of prestressed composite rotor blade spar specimens

NASA Technical Reports Server (NTRS)

Gleich, D.

1974-01-01

Prestressed composite spar specimens were fabricated and evaluated by crack propagation and ballistic penetration tests. The crack propagation tests on flawed specimens showed that the prestressed composite spar construction significantly suppresses crack growth. Damage from three high velocity 30 caliber projectile hits was confined to three small holes in the ballistic test specimen. No fragmentation or crack propagation was observed indicating good ballistic damage resistance. Rotor attachment approaches and improved structural performance configurations were identified. Design theory was verified by tests. The prestressed composite spar configuration consisted of a compressively prestressed high strength ARDEFORM 301 stainless steel liner overwrapped with pretensioned S-994 fiberglass.

Mod-5A wind turbine generator program design report. Volume 4: Drawings and specifications, book 2

NASA Technical Reports Server (NTRS)

1984-01-01

The design, development and analysis of the 7.3 MW MOD-5A wind turbine generator is documented. There are four volumes. This volume contains the drawings and specifications that were developed in preparation for building the MOD-5A wind turbine generator. This is the second book of volume four. Some of the items it contains are specs for the emergency shutdown panel, specs for the simulator software, simulator hardware specs, site operator terminal requirements, control data system requirements, software project management plan, elastomeric teeter bearing requirement specs, specs for the controls electronic cabinet, and specs for bolt pretensioning.

Quasi-static shape adjustment of a 15 meter diameter space antenna

NASA Technical Reports Server (NTRS)

Belvin, W. Keith; Herstrom, Catherine L.; Edighoffer, Harold H.

1987-01-01

A 15 meter diameter Hoop-Column antenna has been analyzed and tested to study shape adjustment of the reflector surface. The Hoop-Column antenna concept employs pretensioned cables and mesh to produce a paraboloidal reflector surface. Fabrication errors and thermal distortions may significantly reduce surface accuracy and consequently degrade electromagnetic performance. Thus, the ability to adjust the surface shape is desirable. The shape adjustment algorithm consisted of finite element and least squares error analyses to minimize the surface distortions. Experimental results verified the analysis. Application of the procedure resulted in a reduction of surface error by 38 percent. Quasi-static shape adjustment has the potential for on-orbit compensation for a variety of surface shape distortions.

Fear of a Black femme: The existential conundrum of embodying a Black femme identity while being a professor of Black, queer, and feminist studies.

PubMed

Story, Kaila Adia

2017-10-02

Although a Black femme identity has been defined and embodied by many as an identity with Black feminist roots and revolutionary potentials, Black femmes are still rendered hypervisible and invisible through racist and heteronormative politics. Similarly, embodying a Black femme identity as a professor in academia often engenders these same pretenses of hypervisibility and invisibility. This essay explores what this existential conundrum has been for me as both a Black femme and professor of Black queer and feminist studies, while illuminating the mix of forces within academia that have attempted to stifle my chosen sexual identity and gendered performance.

On slaves and genes: "origins" and "processes" in genetic studies of the Brazilian population.

PubMed

Calvo-González, Elena

2014-01-01

In this article I examine how contemporary geneticists investigating the history and configuration of the Brazilian population engage with other academic disciplines. To do so I use as a case study some articles published by geneticists researching the presence of hemoglobin S variants in Brazil, in which there is a clear pretension to contribute to the analysis of issues such as slavery or Brazil's ethnic identity. By contrasting these studies with contemporary works from history and the social science, the explanatory centrality of "origin" in the genetic studies analyzed is problematized, as is the lack of interaction with the epistemological characteristics of other areas of knowledge.

Mother-child play: children with Down syndrome and typical development.

PubMed

Venuti, P; de Falco, S; Esposito, G; Bornstein, Marc H

2009-07-01

Child solitary and collaborative mother-child play with 21 children with Down syndrome and 33 mental-age-matched typically developing children were compared. In solitary play, children with Down syndrome showed less exploratory but similar symbolic play compared to typically developing children. From solitary to collaborative play, children with Down syndrome increased their exploratory play, attaining the same level as typically developing children. Pretense significantly increased from solitary to collaborative play only in typically developing children. Differences between mothers' play in the two groups mirrored those between their children. Both groups showed similar attunement and synchrony. Mothers contribute to the play development of children with Down syndrome through their own adaptation to their children's limitations and potentialities.

The place of the ideal observer in medical ethics.

PubMed

Churchill, L R

1983-01-01

The idea of an ideal observer is frequently employed in ethical reasoning and has recently been introduced into medical ethics. The contemporary use of this idea, however, is deeply flawed. It ignores important social and personal dimensions of ethics. By espousing a perspective of observation removed from history and community, the ideal observer notion encourages a pretense of objectivity and overlooks the distortions of distance. If taken seriously as a model for choice, the ideal observer is incoherent, as it dispenses with the concrete moral agent and the locus of choice. Adam Smith's 'impartial spectator' is examined as a more adequate statement of the need for appreciating diverse perspectives in ethical choices.

Dynamic Testing of a Subscale Sunshield for the Next Generation Space Telescope (NGST)

NASA Technical Reports Server (NTRS)

Lienard, Sebastien; Johnston, John D.; Ross, Brian; Smith, James; Brodeur, Steve (Technical Monitor)

2001-01-01

The NGST sunshield is a lightweight, flexible structure consisting of multiple layers of pretensioned, thin-film membranes supported by deployable booms. The structural dynamic behavior of the sunshield must be well understood in order to predict its influence on observatory performance. Ground tests were carried out in a vacuum environment to characterize the structural dynamic behavior of a one-tenth scale model of the sunshield. Results from the tests will be used to validate analytical modeling techniques that can be used in conjunction with scaling laws to predict the performance of the full-sized structure. This paper summarizes the ground tests and presents representative results for the dynamic behavior of the sunshield.

Biomechanical performance of different cable and wire cerclage configurations.

PubMed

Lenz, Mark; Perren, Stephan Marcel; Richards, Robert Geoff; Mückley, Thomas; Hofmann, Gunther Olaf; Gueorguiev, Boyko; Windolf, Markus

2013-01-01

Cerclage technology is regaining interest due to the increasing number of periprosthetic fractures. Different wiring techniques have been formerly proposed and have hibernated over years. Hereby, they are compared to current cerclage technology. Seven groups (n = 6) of different cable cerclage (Ø1.7 mm, crimp closure) configurations (one single cerclage looped once around the shells, one single cerclage looped twice, two cerclages each looped once) and solid wire cerclages (Ø1.5 mm, twist closure) (same configurations as cable cerclages, and two braided wires, twisted around each other looped once) fixed two cortical half shells of human femoral shaft mounted on a testing jig. Sinusoidal cyclic loading with constantly increasing force (0.1 N/cycle) was applied starting at 50 N peak load. Cerclage pretension (P), load leading to onset of plastic deformation (D) and load at total failure (T) were identified. Statistical differences between the groups were detected by univariate ANOVA. Double looped cables (P442N ± 129; D1334N ± 319; T2734N ± 330) performed significantly better (p < 0.05) than single looped cables (P292N ± 56; D646N ± 108; T1622N ± 171) and were comparable to two single cables (P392N ± 154; D1191N ± 334; T2675N ± 361). Double looped wires (P335N ± 49; D752N ± 119; T1359N ± 80) were significantly better (p < 0.05) than single looped wires (P181N ± 16; D343N ± 33; T606N ± 109) and performed similarly to single looped cables. Braided wires (P119N ± 26; D225N ± 55; T919N ± 197) exhibited early loss of pretension and plastic deformation. Double looped cerclages provided a better fixation stability compared to a single looped cerclage. Double looped wires were comparable to a single looped cable. The use of braided wires could not be recommended mechanically.

Mother-child play in children with Down syndrome and typical development

PubMed Central

Venuti, P.; de Falco, S.; Esposito, G.; Bornstein, Marc H.

2014-01-01

The present study compares child solitary and collaborative play with mother in 21 children with Down syndrome (DS) and 33 mental-age-matched typically developing (TD) children. In solitary play, children with DS showed less exploratory but similar symbolic play compared to TD children. From solitary to collaborative play, children with DS increased their exploratory play attaining the same level as TD children; Pretense significantly increased from solitary to collaborative play only in TD children . Differences between mothers’ play in the two groups mirrored those between their children. Child and mother play in both groups showed similar attunement and synchrony. Mothers contribute to the play development of children with DS through their own adaptation to their children’s limitations and potentialities alike. PMID:19642713

Parametric Study of the Effect of Membrane Tension on Sunshield Dynamics

NASA Technical Reports Server (NTRS)

Ross, Brian; Johnston, John D.; Smith, James

2002-01-01

The NGST sunshield is a lightweight, flexible structure consisting of pretensioned membranes supported by deployable booms. The structural dynamic behavior of the sunshield must be well understood in order to predict its influence on observatory performance. A 1/10th scale model of the sunshield has been developed for ground testing to provide data to validate modeling techniques for thin film membrane structures. The validated models can then be used to predict the behaviour of the full scale sunshield. This paper summarizes the most recent tests performed on the 1/10th scale sunshield to study the effect of membrane preload on sunshield dynamics. Topics to be covered include the test setup, procedures, and a summary of results.

Tobacco industry surveillance of public health groups: the case of STAT (Stop Teenage Addiction to Tobacco) and INFACT (Infant Formula Action Coalition).

PubMed

Malone, Ruth E

2002-06-01

The goal of this study was to describe how the tobacco industry collects information about public health groups. Publicly available internal tobacco industry documents were reviewed and analyzed using a chronological case study approach. The industry engaged in aggressive intelligence gathering, used intermediaries to obtain materials under false pretenses, sent public relations spies to the organizations' meetings, and covertly taped strategy sessions. Other industry strategies included publicly minimizing the effects of boycotts, painting health advocates as "extreme," identifying and exploiting disagreements, and planning to "redirect the funding" of tobacco control organizations to other purposes. Public health advocates often make light of tobacco industry observers, but industry surveillance may be real, intense, and covert and may obstruct public health initiatives.

Behavior of a nuclear steel containment equipment hatch at large strain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fanous, F.; Greimann, L.

1988-05-01

During a severe accident, buckling of a steel containment hatch door, large deformation and ovaling of the hatch sleeve are potential causes of mismatch at the sealing surface which can result in a leakage path. A three-dimensional nonlinear finite element analysis of a typical steel containment/sleeve/hatch assembly that includes containment stiffeners, pretensioned swing bolts, and hatch door geometric imperfection is presented. The analysis was carried out to the nonlinear range up to large strains. The results indicated that the buckling load occurs at pressure, far above that which causes gross yielding of the shell plate. Although buckling of the hatchmore » door increased the relative motions of the hatch sleeve and the hatch door, the motions remained sufficiently small to prevent leakage.« less

Quotable physics

NASA Astrophysics Data System (ADS)

Chomet, Seweryn

2008-03-01

Anton Capri is an alumnus of Princeton University, where he specialized in quantum field theory, and, since 1998, has been a distinguished professor emeritus at the University of Alberta in Canada. Since his nominal retirement he has devoted much of his time to writing and has now published, among other things, two linked books that present a variety of anecdotes involving famous physicists, as well as useful biographical sketches of them. The origin of these books is clearly defined by their author. "I have not any pretensions to having produced a 'scholarly' work," he writes. "Some of the stories recorded here are gossip, or physics folklore. I have tried to verify as many of the stories as I could, but I have not hesitated to include all stories that I heard and noted down."

Designer Drugs: A Synthetic Catastrophe.

PubMed

Fratantonio, James; Andrade, Lawrence; Febo, Marcelo

Synthetic stimulants can cause hallucinations, aggressive behaviors, death and are sometimes legal. These substances are sold as plant food and bath salts that are "Not for Human Consumption", therefore skirting the 1986 Federal Analogue Act and giving a false pretense of safety. Studies have proved that these substances are toxic, have a high abuse potential, and are becoming extremely prevalent in the United States. This creates a dilemma for law enforcement agents, hospitals, and substance use disorder treatment centers. Urine Drug Testing is utilized as a clinical diagnostic tool in substance use disorder treatment centers, and the furious pace at which new synthetic stimulants are introduced to the black market are making the detection via urine increasingly difficult. This article will discuss the prevalence, pharmacology and difficulty developing laboratory assays to detect synthetic stimulants.

Knowledge of damage identification about tensegrities via flexibility disassembly

NASA Astrophysics Data System (ADS)

Jiang, Ge; Feng, Xiaodong; Du, Shigui

2017-12-01

Tensegrity structures composing of continuous cables and discrete struts are under tension and compression, respectively. In order to determine the damage extents of tensegrity structures, a new method for tensegrity structural damage identification is presented based on flexibility disassembly. To decompose a tensegrity structural flexibility matrix into the matrix represention of the connectivity between degress-of-freedoms and the diagonal matrix comprising of magnitude informations. Step 1: Calculate perturbation flexibility; Step 2: Compute the flexibility connectivity matrix and perturbation flexibility parameters; Step 3: Calculate the perturbation stiffness parameters. The efficiency of the proposed method is demonstrated by a numeical example comprising of 12 cables and 4 struts with pretensioned. Accurate identification of local damage depends on the availability of good measured data, an accurate and reasonable algorithm.

Tobacco Industry Surveillance of Public Health Groups: The Case of STAT and INFACT

PubMed Central

Malone, Ruth E.

2002-01-01

Objectives. The goal of this study was to describe how the tobacco industry collects information about public health groups. Methods. Publicly available internal tobacco industry documents were reviewed and analyzed using a chronological case study approach. Results. The industry engaged in aggressive intelligence gathering, used intermediaries to obtain materials under false pretenses, sent public relations spies to the organizations' meetings, and covertly taped strategy sessions. Other industry strategies included publicly minimizing the effects of boycotts, painting health advocates as “extreme,” identifying and exploiting disagreements, and planning to “redirect the funding” of tobacco control organizations to other purposes. Conclusions. Public health advocates often make light of tobacco industry observers, but industry surveillance may be real, intense, and covert and may obstruct public health initiatives. PMID:12036789

Barnard’s Star: Planets or Pretense

NASA Astrophysics Data System (ADS)

Bartlett, Jennifer L.; Ianna, P. A.

2014-01-01

Barnard’s Star remains popular with planet hunters because it is not only an extremely near, high proper motion star, but also the object of early planet-detection claims. In 1963, van de Kamp explained perturbations in its proper motion by the presence of a planet. In 1969, he produced another single-planet solution and a two-planet solution to the astrometric wobbles detected. At least 19 studies have failed to confirm his results using a range of techniques, including radial velocity, direct imaging, and speckle interferometry. However, most of them lacked the sensitivity to detect the planets he described, including astrometric studies at the McCormick and Naval Observatories. However, radial-velocity monitoring of Barnard’s Star at Lick and Keck Observatories from 1987 through 2012 appears to have ruled out such planets. Based upon observations made at the Sproul Observatory between 1916 and 1962, van de Kamp claimed that Barnard’s Star had a planet with about 1.6 times the mass of Jupiter and an orbital period of 24 years. After accounting for instrumentation effects that might have been partially responsible for his initial results, he continued to assert that this red dwarf had two planets. In his 1982 analysis of ~20,000 exposures collected between 1938 and 1981, he calculated that two planets with 0.7- and 0.5-Jupiter masses in 12- and 20-year orbits, respectively, orbited the second-closest stellar system to our own. Starting in 1995, the dramatic successes of radial velocity searches for extrasolar planets drove van de Kamp’s unsubstantiated claims from popular consciousness. Although many low-mass stellar companions were discovered through astrometry, the technique has been less successful for planets: “The Extrasolar Planets Encyclopaedia” identifies one such discovery out of the 997 planets listed on 2013 September 23. Although Barnard’s Star has lost its pretensions to hosting the first extrasolar planets known, its intrinsic properties will keep it under observation. NSF grant AST 98-20711, Litton Marine Systems, Levinson Fund, University of Virginia, Hampden-Sydney College, and US Naval Observatory supported this research.

Synchronous Measuring Techniques in Parallel to MRE: Study of Pressure, Pre-Tension, and Surface Dynamics

NASA Astrophysics Data System (ADS)

Brinker, Spencer Thomas

The contents of this dissertation include investigations in Magnetic Resonance Elastography (MRE) using a preclinical 9.4 Tesla small animal Magnetic Resonance Imaging (MRI) system along with synthetic materials that mimic the mechanical properties of soft human tissue. MRE is used for studying the mechanical behavior of soft tissue particularly applicable to medical applications. Wave motion induced by a mechanical driver is measured with MRI to acquire internal displacement fields over time and space within a material media. Complex shear modulus of the media is calculated from the response of mechanical wave transmission through the material. Changes in soft tissue stiffness is associated with disease progression and thus, is why assessing tissue mechanical properties with MRE has powerful diagnostic potential due to the noninvasive procedure of MRI. The experiments performed in this dissertation used elastic phantoms and specimens to observe the influence of pre-stress on MRE derived mechanical properties while additional mechanical measurements from other related material testing methods were synchronously collected alongside MRI scanning. An organ simulating phantom was used to explore changes in MRE stiffness in response to gas and liquid cyclic pressure loading. MRE stiffness increased with pressure and hysteresis was observed in cyclic pressure loading. The results suggest MRE is applicable to pressure related disease assessment. In addition, an interconnected porosity pressure phantom was constructed for future porous media investigations. A custom system was also built to demonstrate concurrent tensile testing during MRE for investigating homogeneous soft material media undergoing pre-tension. Stiffness increased with uniaxial tensile stress and strain. The tension and stiffness relationship explored can be related to the stress analysis of voluntary muscle. The results also offer prospective experimental strategies for community wide standards on MRE calibration methods. Lastly, a novel platform was developed for synchronous acquisition of Scanning Laser Doppler Vibrometry (SLDV) and MRE for examining surface wave dynamics related to internal media wave propagation in soft material experiencing sinusoidal mechanical excitation. The results indicate that optical displacement measurements of media on the surface are similar in nature to internal displacement measured from MRE. It is concluded that optical and MRI based elastography yield similar values of complex shear modulus.

NASA Has Joined America True's Design Mission for 2000

NASA Technical Reports Server (NTRS)

Steele, Gynelle C.

1999-01-01

Engineers at the NASA Lewis Research Center will support the America True design team led by America s Cup innovator Phil Kaiko. The joint effort between NASA and America True is encouraged by Mission HOME, the official public awareness campaign of the U.S. space community. NASA Lewis and America True have entered into a Space Act Agreement to focus on the interaction between the airfoil and the large deformation of the pretensioned sails and rigs along with the dynamic motions related to the boat motions. This work will require a coupled fluid and structural simulation. Included in the simulation will be both a steadystate capability, to capture the quasi-state interactions between the air loads and sail geometry and the lift and drag on the boat, and a transient capability, to capture the sail/mast pumping effects resulting from hull motions.

Focusing solar collector and method for manufacturing same

DOEpatents

Murphy, Lawrence M.

1984-01-01

Disclosed is a solar collector comprising an annular-shaped frame and a composite membrane member for concentrating and focusing sun radiation. The composite membrane member is supported and tensioned by the frame and consists of first and second differentially pretensioned sheet members which are integrally bonded to one another. The frame and one of the two sheet members are adapted to allow tensions in both of the sheets to be adjusted. Subsequent to bonding and upon adjusting a tension in one of the two sheet members, both of the two bonded sheet members react with one another so as to cause the composite membrane member to have a contoured configuration, which enables the membrane member to be focusable. Additionally, adjusting the tension in one of the two sheet members provides a reciprocal adjustment in a focus provided by the membrane member.

Focusing solar collector and method for manufacturing same

DOEpatents

Murphy, L.M.

1984-01-01

Disclosed is a solar collector comprising an annular-shaped frame and a composite membrane member for concentrating and focusing sun radiation. The composite membrane member is supported and tensioned by the frame and consists of first and second differentially pretensioned sheet members which are integrally bonded to one another. The frame and one of the two sheet members are adapted to allow tensions in both of the two sheets to be adjusted. Subsequent to bonding and upon adjusting a tension in one of the two sheet members, both of the two bonded sheet members react with one another so as to cause the composite membrane member to have a contoured configuration, which enables the membrane member to be focusable. Additionally, adjusting the tension in one of the two sheet members provides a reciprocal adjustment in a focus provided by the membrane member.

Topologically Optimized Nano-Positioning Stage Integrating with a Capacitive Comb Sensor.

PubMed

Chen, Tao; Wang, Yaqiong; Liu, Huicong; Yang, Zhan; Wang, Pengbo; Sun, Lining

2017-01-28

Nano-positioning technology has been widely used in many fields, such as microelectronics, optical engineering, and micro manufacturing. This paper presents a one-dimensional (1D) nano-positioning system, adopting a piezoelectric ceramic (PZT) actuator and a multi-objective topological optimal structure. The combination of a nano-positioning stage and a feedback capacitive comb sensor has been achieved. In order to obtain better performance, a wedge-shaped structure is used to apply the precise pre-tension for the piezoelectric ceramics. Through finite element analysis and experimental verification, better static performance and smaller kinetic coupling are achieved. The output displacement of the system achieves a long-stroke of up to 14.7 μm and high-resolution of less than 3 nm. It provides a flexible and efficient way in the design and optimization of the nano-positioning system.

Beyond semantic accuracy: preschoolers evaluate a speaker's reasons.

PubMed

Koenig, Melissa A

2012-01-01

Children's sensitivity to the quality of epistemic reasons and their selective trust in the more reasonable of 2 informants was investigated in 2 experiments. Three-, 4-, and 5-year-old children (N = 90) were presented with speakers who stated different kinds of evidence for what they believed. Experiment 1 showed that children of all age groups appropriately judged looking, reliable testimony, and inference as better reasons for belief than pretense, guessing, and desiring. Experiment 2 showed that 3- and 4-year-old children preferred to seek and accept new information from a speaker who was previously judged to use the "best" way of thinking. The findings demonstrate that children distinguish certain good from bad reasons and prefer to learn from those who showcased good reasoning in the past. © 2012 The Author. Child Development © 2012 Society for Research in Child Development, Inc.

Reflections on the evidence for a vulnerability locus for Schizophrenia on chromosome 6p24-22

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kendler, K.S.; Straub, R.E.; MacLean, C.J.

A recent series of studies have attempted to replicate evidence for a vulnerability locus for schizophrenia on chromosome 6p initially detected in the Irish Study of High-Density Schizophrenia Families (ISHDSF). Here, we want to comment briefly on these findings and respond to some of the issues raised in the preceding article by Baron. We disclaim, however, any pretensions to a definitive interpretation of the available evidence. Our level of ignorance in the interpretation of linkage evidence for complex psychiatric syndromes is too profound. Rather, we seek to make educated guesses on the basis of our understanding of the principles ofmore » linkage analysis, on our knowledge of the problems of statistical inference and on our intuition of how genes might influence vulnerability to complex human behavioral traits. 27 refs.« less

Vibration characteristics and damage detection in a suspension bridge

NASA Astrophysics Data System (ADS)

Wickramasinghe, Wasanthi R.; Thambiratnam, David P.; Chan, Tommy H. T.; Nguyen, Theanh

2016-08-01

Suspension bridges are flexible and vibration sensitive structures that exhibit complex and multi-modal vibration. Due to this, the usual vibration based methods could face a challenge when used for damage detection in these structures. This paper develops and applies a mode shape component specific damage index (DI) to detect and locate damage in a suspension bridge with pre-tensioned cables. This is important as suspension bridges are large structures and damage in them during their long service lives could easily go un-noticed. The capability of the proposed vibration based DI is demonstrated through its application to detect and locate single and multiple damages with varied locations and severity in the cables of the suspension bridge. The outcome of this research will enhance the safety and performance of these bridges which play an important role in the transport network.

Topologically Optimized Nano-Positioning Stage Integrating with a Capacitive Comb Sensor

PubMed Central

Chen, Tao; Wang, Yaqiong; Liu, Huicong; Yang, Zhan; Wang, Pengbo; Sun, Lining

2017-01-01

Nano-positioning technology has been widely used in many fields, such as microelectronics, optical engineering, and micro manufacturing. This paper presents a one-dimensional (1D) nano-positioning system, adopting a piezoelectric ceramic (PZT) actuator and a multi-objective topological optimal structure. The combination of a nano-positioning stage and a feedback capacitive comb sensor has been achieved. In order to obtain better performance, a wedge-shaped structure is used to apply the precise pre-tension for the piezoelectric ceramics. Through finite element analysis and experimental verification, better static performance and smaller kinetic coupling are achieved. The output displacement of the system achieves a long-stroke of up to 14.7 μm and high-resolution of less than 3 nm. It provides a flexible and efficient way in the design and optimization of the nano-positioning system. PMID:28134854

Book Review

NASA Astrophysics Data System (ADS)

Vickridge, Ian

2007-09-01

These two volumes present a series of papers that have arisen from a discussion meeting held at the Royal Danish Academy of Sciences and Letters in May 2006, under a strong impetus from Prof. Peter Sigmund. A significant number of central players in the 'ion beam' family were invited to participate in the discussions and most of them contributed to these two volumes. The prime purpose of the volumes, as stated in the Abstract, is 'to help those engaged in basic and applied research within ion-beam science to stay or become alert with respect to central problems in and around their area', whilst not having the pretension to be either 'a comprehensive review or a tutorial'. The overall result is stunning, and ion beam scientists from all realms are likely to want these two volumes, which together comprise some 750 pages, on their bookshelves.

Slow Movements of Bio-Inspired Limbs

NASA Astrophysics Data System (ADS)

Babikian, Sarine; Valero-Cuevas, Francisco J.; Kanso, Eva

2016-10-01

Slow and accurate finger and limb movements are essential to daily activities, but the underlying mechanics is relatively unexplored. Here, we develop a mathematical framework to examine slow movements of tendon-driven limbs that are produced by modulating the tendons' stiffness parameters. Slow limb movements are driftless in the sense that movement stops when actuations stop. We demonstrate, in the context of a planar tendon-driven system representing a finger, that the control of stiffness suffices to produce stable and accurate limb postures and quasi-static (slow) transitions among them. We prove, however, that stable postures are achievable only when tendons are pretensioned, i.e., they cannot become slack. Our results further indicate that a non-smoothness in slow movements arises because the precision with which individual stiffnesses need to be altered changes substantially throughout the limb's motion.

Wavelet-based spectral finite element dynamic analysis for an axially moving Timoshenko beam

NASA Astrophysics Data System (ADS)

Mokhtari, Ali; Mirdamadi, Hamid Reza; Ghayour, Mostafa

2017-08-01

In this article, wavelet-based spectral finite element (WSFE) model is formulated for time domain and wave domain dynamic analysis of an axially moving Timoshenko beam subjected to axial pretension. The formulation is similar to conventional FFT-based spectral finite element (SFE) model except that Daubechies wavelet basis functions are used for temporal discretization of the governing partial differential equations into a set of ordinary differential equations. The localized nature of Daubechies wavelet basis functions helps to rule out problems of SFE model due to periodicity assumption, especially during inverse Fourier transformation and back to time domain. The high accuracy of WSFE model is then evaluated by comparing its results with those of conventional finite element and SFE results. The effects of moving beam speed and axial tensile force on vibration and wave characteristics, and static and dynamic stabilities of moving beam are investigated.

President's message: We must remain committed to scientific integrity

NASA Astrophysics Data System (ADS)

McPhaden, Michael

2012-02-01

During the third week of February our global community of Earth and space scientists witnessed the shocking fall from grace of an accomplished AGU member who betrayed the principles of scientific integrity. In doing so he compromised AGU's credibility as a scientific society, weakened the public's trust in scientists, and produced fresh fuel for the unproductive and seemingly endless ideological firestorm surrounding the reality of the Earth's changing climate. Peter Gleick resigned as chair of AGU's Task Force on Scientific Ethics on 16 February, prior to admitting in a blog post that he obtained documents from the Heartland Institute under false pretenses. His transgression cannot be condoned, regardless of his motives. It is a tragedy that requires us to stop and reflect on what we value as scientists and how we want to be perceived by the public. Here are a few things that come immediately to mind:

Dynamic Analysis of Large In-Space Deployable Membrane Antennas

NASA Technical Reports Server (NTRS)

Fang, Houfei; Yang, Bingen; Ding, Hongli; Hah, John; Quijano, Ubaldo; Huang, John

2006-01-01

This paper presents a vibration analysis of an eight-meter diameter membrane reflectarray antenna, which is composed of a thin membrane and a deployable frame. This analysis process has two main steps. In the first step, a two-variable-parameter (2-VP) membrane model is developed to determine the in-plane stress distribution of the membrane due to pre-tensioning, which eventually yields the differential stiffness of the membrane. In the second step, the obtained differential stiffness is incorporated in a dynamic equation governing the transverse vibration of the membrane-frame assembly. This dynamic equation is then solved by a semi-analytical method, called the Distributed Transfer Function Method (DTFM), which produces the natural frequencies and mode shapes of the antenna. The combination of the 2-VP model and the DTFM provides an accurate prediction of the in-plane stress distribution and modes of vibration for the antenna.

Quantification of Processing Effects on Filament Wound Pressure Vessels

NASA Technical Reports Server (NTRS)

Aiello, Robert A.; Chamis, Christos C.

1999-01-01

A computational simulation procedure is described which is designed specifically for the modeling and analysis of filament wound pressure vessels. Cylindrical vessels with spherical or elliptical end caps can be generated automatically. End caps other than spherical or elliptical may be modeled by varying circular sections along the x-axis according to the C C! end cap shape. The finite element model generated is composed of plate type quadrilateral shell elements on the entire vessel surface. This computational procedure can also be sued to generate grid, connectivity and material cards (bulk data) for component parts of a larger model. These bulk data are assigned to a user designated file for finite element structural/stress analysis of composite pressure vessels. The procedure accommodates filament would pressure vessels of all types of shells-of-revolution. It has provisions to readily evaluate initial stresses due to pretension in the winding filaments and residual stresses due to cure temperature.

Quantification of Processing Effects on Filament Wound Pressure Vessels. Revision

NASA Technical Reports Server (NTRS)

Aiello, Robert A.; Chamis, Christos C.

2002-01-01

A computational simulation procedure is described which is designed specifically for the modeling and analysis of filament wound pressure vessels. Cylindrical vessels with spherical or elliptical end caps can be generated automatically. End caps other than spherical or elliptical may be modeled by varying circular sections along the x-axis according to the end cap shape. The finite element model generated is composed of plate type quadrilateral shell elements on the entire vessel surface. This computational procedure can also be used to generate grid, connectivity and material cards (bulk data) for component parts of a larger model. These bulk data are assigned to a user designated file for finite element structural/stress analysis of composite pressure vessels. The procedure accommodates filament wound pressure vessels of all types of shells-of -revolution. It has provisions to readily evaluate initial stresses due to pretension in the winding filaments and residual stresses due to cure temperature.

FE Modelling of the Fluid-Structure-Acoustic Interaction for the Vocal Folds Self-Oscillation

NASA Astrophysics Data System (ADS)

Švancara, Pavel; Horáček, J.; Hrůza, V.

The flow induced self-oscillation of the human vocal folds in interaction with acoustic processes in the simplified vocal tract model was explored by three-dimensional (3D) finite element (FE) model. Developed FE model includes vocal folds pretension before phonation, large deformations of the vocal fold tissue, vocal folds contact, fluid-structure interaction, morphing the fluid mesh according the vocal folds motion (Arbitrary Lagrangian-Eulerian approach), unsteady viscous compressible airflow described by the Navier-Stokes equations and airflow separation during the glottis closure. Iterative partitioned approach is used for modelling the fluid-structure interaction. Computed results prove that the developed model can be used for simulation of the vocal folds self-oscillation and resulting acoustic waves. The developed model enables to numerically simulate an influence of some pathological changes in the vocal fold tissue on the voice production.

A study of structural concepts for ultralightweight spacecraft

NASA Technical Reports Server (NTRS)

Miller, R. K.; Knapp, K.; Hedgepeth, J. M.

1984-01-01

Structural concepts for ultralightweight spacecraft were studied. Concepts for ultralightweight space structures were identified and the validity of heir potential application in advanced spacecraft was assessed. The following topics were investigated: (1) membrane wrinkling under pretensioning; (2) load-carrying capability of pressurized tubes; (3) equilibrium of a precompressed rim; (4) design of an inflated reflector spacecraft; (5) general instability of a rim; and (6) structural analysis of a pressurized isotensoid column. The design approaches for a paraboloidal reflector spacecraft included a spin-stiffened design, both inflated and truss central columns, and to include both deep truss and rim-stiffened geodesic designs. The spinning spacecraft analysis is included, and the two truss designs are covered. The performances of four different approaches to the structural design of a paraboloidal reflector spacecraft are compared. The spinning and inflated configurations result in very low total masses and some concerns about their performance due to unresolved questions about dynamic stability and lifetimes, respectively.

Survey of the Physical and Environmental Parameters of the Moon

NASA Technical Reports Server (NTRS)

Niedz, F. J.; Kopal, Zdenek

1963-01-01

This document presents, in summary, a compilation of the physical and environmental parameters of the moon. A determined attempt has been made to be objective at all times. Many of the physical sciences are presented in sufficient depth to adequately identify the basic information available. It is expected that the appropriate references will be consulted when additional detail is required. It is obvious both from the text and the reference material that divergent opinions prevail and uncertainties exist in almost every phase of lunar science; e.g., the existence of the lunar bulge, the thickness of the dust layer, etc. No pretense is made to resolve these differences, but by bringing together many references, it is hoped that some contribution will be made in lunar science. The subject index will be of particular value since it relates the reference section by subject. A glossary of terms used throughout the text is also provided.

Moral Expertise in the Clinic: Lessons Learned from Medicine and Science

PubMed Central

McClimans, Leah; Slowther, Anne

2016-01-01

Philosophers and others have questioned whether or not expertise in morality is possible. This debate is not only theoretical, but also affects the perceived legitimacy of clinical ethicists. One argument against moral expertise is that in a pluralistic society with competing moral theories no one can claim expertise regarding what another ought morally to do. There are simply too many reasonable moral values and intuitions that affect theory choice and its application; expertise is epistemically uniform. In this article, we discuss how similar concerns have recently threatened to undermine expertise in medicine and science. In contrast, we argue that the application of values is needed to exercise medical, scientific, and moral expertise. As long as these values are made explicit, worries about a pretense to authority in the context of a liberal democracy are ill-conceived. In conclusion, we argue for an expertise that is epistemically diverse. PMID:27302969

Dynamics of a 4x6-Meter Thin Film Elliptical Inflated Membrane for Space Applications

NASA Technical Reports Server (NTRS)

Casiano, Matthew J.; Hamidzadeh, Hamid R.; Tinker, Michael L.; McConnaughey, Paul R. (Technical Monitor)

2002-01-01

Dynamic characterization of a thin film inflatable elliptical structure is described in detail. A two-step finite element modeling approach in MSC/NASTRAN is utilized, consisting of (1) a nonlinear static pressurization procedure used to obtain the updated stiffness matrix, and (2) a modal "restart" eigen solution that uses the modified stiffness matrix. Unique problems encountered in modeling of this large Hexameter lightweight inflatable arc identified, including considerable difficulty in obtaining convergence in the nonlinear finite element pressurization solution. It was found that the extremely thin polyimide film material (.001 in or 1 mil) presents tremendous problems in obtaining a converged solution when internal pressure loading is applied. Approaches utilized to overcome these difficulties are described. Comparison of finite element predictions for frequency and mode shapes of the inflated structure with closed-form solutions for a flat pre-tensioned membrane indicate reasonable agreement.

Occupant restraint in the rear seat: ATD responses to standard and pre-tensioning, force-limiting belt restraints.

PubMed

Forman, Jason; Michaelson, Jarett; Kent, Richard; Kuppa, Shashi; Bostrom, Ola

2008-10-01

Recent studies have shown that restrained occupants over the age of 50 in frontal crashes have a higher risk of injury in the rear seat than in the front, and have hypothesized that the incorporation of technology such as belt pre-tensioning and force limiting preferentially in the front seat is at least partially responsible for this trend. This study investigates the potential benefits and trade-offs of seat belt pretensioners and force-limiters in the rear seat using a series of frontal impact sled tests at two speeds (48 km/h and 29 km/h DeltaV) with a buck representing the interior of the reat seat occupant compartment of a contemporary mid-sized sedan. Four different dummies were tested: the Hybrid III six year old (in a booster seat, H3 6YO), the Hybrid III 5(th) percentile female (H3 AF05), the Hybrid III 50(th) percentile male (H3 AM50), and the THOR-NT. The restraints consisted of either a standard three point belt, or a 3-point belt with a retractor pretensioner and a progressive force-limiter (FL+PT). Each test condition was repeated in triplicate. The FL+PT restraints (compared to the standard restraints) resulted in a significant (p < or = 0.05) decrease in peak internal chest deflection for each of the Hybrid III dummies at both test speeds (48 km/h: 29% decrease for H3 6YO, 38% decrease for H3 AF05, 30% decrease for H3 AM50), and for the THOR-NT at a DeltaV of 29 km/h. At 48 km/h, the FL+PT restraint qualitatively decreased the average peak internal chest deflection of the THOR-NT, however this decrease was not statistically significant (p=0.06). Furthermore, the FL+PT system allowed little or no increase in forward head excursion, and improved whole-body kinematics for all dummies by restricting pelvic excursion and slightly increasing torso pitch. The results suggest that the FL+PT system studied here may provide injury-reducing benefit to rear seat occupants in moderate to high severity frontal crashes, although more study is needed to evaluate these restraints in other crash scenarios.

Persistence of biological nitrogen fixation in high latitude grass-clover grasslands under different management practices

NASA Astrophysics Data System (ADS)

Tzanakakis, Vasileios; Sturite, Ievina; Dörsch, Peter

2016-04-01

Biological nitrogen fixation (BNF) can substantially contribute to N supply in permanent grasslands, improving N yield and forage quality, while reducing inorganic N inputs. Among the factors critical to the performance of BNF in grass-legume mixtures are selected grass and legume species, proportion of legumes, the soil-climatic conditions, in particular winter conditions, and management practices (e.g. fertilization and compaction). In high latitude grasslands, low temperatures can reduce the performance of BNF by hampering the legumés growth and by suppressing N2 fixation. Estimation of BNF in field experiments is not straightforward. Different methods have been developed providing different results. In the present study, we evaluated the performance of BNF, in a newly established field experiment in North Norway over four years. The grassland consisted of white clover (Trifolium repens L.) and red clover (Trifolium pretense L.) sawn in three proportions (0, 15 and 30% in total) together with timothy (Pheum pretense L.) and meadow fescue (Festuca pratensis L.). Three levels of compaction were applied each year (no tractor, light tractor, heavy tractor) together with two different N rates (110 kg N/ha as cattle slurry or 170 kg N/ha as cattle slurry and inorganic N fertilizer). We applied two different methods, the 15N natural abundance and the difference method, to estimate BNF in the first harvest of each year. Overall, the difference method overestimated BNF relative to the 15N natural abundance method. BNF in the first harvest was compared to winter survival of red and white clover plants, which decreased with increasing age of the grassland. However, winter conditions did not seem to affect the grassland's ability to fix N in spring. The fraction of N derived from the atmosphere (NdfA) in white and red clover was close to 100% in each spring, indicating no suppression of BNF. BNF increased the total N yield of the grasslands by up to 75%, mainly due to high N-yields in red clover. However, the total biomass and N yield of red clover decreased dramatically throughout the following years, reflecting the negative cumulative effect of N fertilization and compaction. Overall, BNF by clover can contribute substantially to N supply to northern grasslands, but better cultivation strategies are needed to improve the persistence of clover.

DTFM Modeling and Analysis Method for Gossamer Structures

NASA Technical Reports Server (NTRS)

Fang, Hou-Fei; Lou, Michael; Broduer, Steve (Technical Monitor)

2001-01-01

Gossamer systems are mostly composed of support structures formed by highly flexible, long tubular elements and pre-tensioned thin-film membranes. These systems offer order-of-magnitude reductions in mass and launch volume and will revolutionize the architecture and design of space flight systems that require large in-orbit configurations and apertures. A great interest has been generated in recent years to fly gossamer systems on near-term and future space missions. Modeling and analysis requirements for gossamer structures are unique. Simulation of in-space performance issues of gossamer structures, such as inflation deployment of flexible booms, formation and effects of wrinkle in tensioned membranes, synthesis of tubular and membrane elements into a complete structural system, usually cannot be accomplished by using the general-purpose finite-element structural analysis codes. This has led to the need of structural modeling and analysis capabilities specifically suitable for gossamer structures. The Distributed Transfer Function Method (DTFM) can potentially meet this urgent need. Additional information is contained in the original extended abstract.

Self-deception as pseudo-rational regulation of belief.

PubMed

Michel, Christoph; Newen, Albert

2010-09-01

Self-deception is a special kind of motivational dominance in belief-formation. We develop criteria which set paradigmatic self-deception apart from related phenomena of auto-manipulation such as pretense and motivational bias. In self-deception rational subjects defend or develop beliefs of high subjective importance in response to strong counter-evidence. Self-deceivers make or keep these beliefs tenable by putting prima-facie rational defense-strategies to work against their established standards of rational evaluation. In paradigmatic self-deception, target-beliefs are made tenable via reorganizations of those belief-sets that relate relevant data to target-beliefs. This manipulation of the evidential value of relevant data goes beyond phenomena of motivated perception of data. In self-deception belief-defense is pseudo-rational. Self-deceivers will typically apply a dual standard of evaluation that remains intransparent to the subject. The developed model of self-deception as pseudo-rational belief-defense is empirically anchored. So, we hope to put forward a promising candidate. Copyright © 2010 Elsevier Inc. All rights reserved.

Optical performances of the FM JEM-X masks

NASA Astrophysics Data System (ADS)

Reglero, V.; Rodrigo, J.; Velasco, T.; Gasent, J. L.; Chato, R.; Alamo, J.; Suso, J.; Blay, P.; Martínez, S.; Doñate, M.; Reina, M.; Sabau, D.; Ruiz-Urien, I.; Santos, I.; Zarauz, J.; Vázquez, J.

2001-09-01

The JEM-X Signal Multiplexing Systems are large HURA codes "written" in a pure tungsten plate 0.5 mm thick. 24.247 hexagonal pixels (25% open) are spread over a total area of 535 mm diameter. The tungsten plate is embedded in a mechanical structure formed by a Ti ring, a pretensioning system (Cu-Be) and an exoskeleton structure that provides the required stiffness. The JEM-X masks differ from the SPI and IBIS masks on the absence of a code support structure covering the mask assembly. Open pixels are fully transparent to X-rays. The scope of this paper is to report the optical performances of the FM JEM-X masks defined by uncertainties on the pixel location (centroid) and size coming from the manufacturing and assembly processes. Stability of the code elements under thermoelastic deformations is also discussed. As a general statement, JEM-X Mask optical properties are nearly one order of magnitude better than specified in 1994 during the ESA instrument selection.

[Limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou].

PubMed

Lin, Wen-Jie; Xiao, Tang-Fu; Ao, Zi-Qiang; Xing, Jun; Ma, Huan-Cheng; Hu, Ting-Xing

2007-03-01

With indigenous zinc smelting waste residue, contaminated soil and background soil as test substrates, a pot experiment was conducted to study the growth characteristics of Lolium perenne and Trifolium pretense on these substrates. The results showed that the major limiting factors of waste land revegetation in indigenous zinc smelting areas of western Guizhou were the salt-alkali stress and the lower contents of organic matter, total N, available N and total K. The heavy metals in waste residue had a high concentration, but their available forms only occupied a small proportion, with low toxicity to plant but having potential harmful risk. Contaminated soil had lower concentrations of heavy metals than waste residue, but its contained heavy metals were more in available form. The constraints of revegetation on contaminated soil were the toxicity of heavy metals and the low contents of available P and K. Mixing contaminated soil with zinc smelting waste residue could be one of the effective approaches for the substrate amendment in indigenous zinc smelting areas.

A comparison of the performance of two advanced restraint systems in frontal impacts.

PubMed

Lopez-Valdes, F J; Juste, O; Pipkorn, B; Garcia-Muñoz, I; Sunnevång, C; Dahlgren, M; Alba, J J

2014-01-01

The goal of the study is to compare the kinematics and dynamics of the THOR dummy in a frontal impact under the action of 2 state-of-the-art restraint systems. Ten frontal sled tests were performed with THOR at 2 different impact speeds (35 and 9 km/h). Two advanced restraint systems were used: a pretensioned force-limiting belt (PT+FL) and a pretensioned belt incorporating an inflatable portion (PT+BB). Dummy measurements included upper and lower neck reactions, multipoint thoracic deflection, and rib deformation. Data were acquired at 10,000 Hz. Three-dimensional motion of relevant dummy landmarks was tracked at 1,000 Hz. RESULTS are reported in a local coordinate system moving with the test buck. Average forward displacement of the head was greater when the PT+FL belt was used (35 km/h: 376.3±16.1 mm [PT+BB] vs. 393.6±26.1 mm [PT+FL]; 9 km/h: 82.1±26.0 mm [PT+BB] vs. 98.8±0.2 mm [PT+FL]). The forward displacement of T1 was greater for the PT+FL belt at 35 km/h but smaller at 9 km/h. The forward motion of the pelvis was greater when the PT+BB was used, exhibiting a difference of 82 mm in the 9 km/h tests and 95.5 mm in the 35 km/h test. At 35 km/h, upper shoulder belt forces were similar (PT+FL: 4,756.8±116.6 N; PT+BB: 4,957.7±116.4 N). At 9 km/h, the PT+BB belt force was significantly greater than the PT+FL one. Lower neck flexion moments were higher for the PT+BB at 35 km/h but lower at 9 km/h (PT+FL: 34.2±3.5 Nm; PT+BB: 26.8±2.1 Nm). Maximum chest deflection occurred at the chest upper left region for both belts and regardless of the speed. The comparison of the performance of different restraints requires assessing occupant kinematics and dynamics from a global point of view. Even if the force acting on the chest is similar, kinematics can be substantially different. The 2 advanced belts compared here showed that while the PT+BB significantly reduced peak and resultant chest deflection, the resulting kinematics indicated an increased forward motion of the pelvis and a reduced rotation of the occupant's torso. Further research is needed to understand how these effects can influence the protection of real occupants in more realistic vehicle environments.

Unproven (questionable) dietary and nutritional methods in cancer prevention and treatment.

PubMed

Herbert, V

1986-10-15

"Unproven" is a euphemism for questionable. The definition of a questionable method is that it has not successfully answered the two basic consumer protection questions of efficacy and safety, to wit: Has it been responsibly, objectively, reproducibly, and reliably demonstrated in humans in the responsible (peer-reviewed) literature accepted for the shelves of the National Library of Medicine in Bethesda, Maryland, to be: More effective than suggestion or doing nothing? and in addition, either As safe as doing nothing? or, in the alternative, If there is any question with respect to safety, to have a reasonably and objectively clear potential for benefit which exceeds its potential for harm? Any proposed cancer prevention or treatment modality which has not successfully answered the above efficacy question plus one of the two safety questions is by definition questionable. It is experimental if it is new, and very probably quackery if it is old. Experimental therapy may be either ethical and responsible or unethical and irresponsible. It is unethical and irresponsible to not tell the patient experiments are being conducted on him, to charge the patient to perform research on him, or to ask the patient to sign an informed consent aimed at exculpating the doctor rather than protecting the patient. Ethical and responsible informed consents clearly delineate that what is being done is experimental, and that efficacy and safety have not been determined. Products promoted for profit to the public without passing peer process are almost without exception ineffective, often harmful, and sometimes lethal. This includes Laetrile, immunoaugmentative therapy, chelation therapy, macrobiotic diets, and other alternative therapies. Anecdotal and testimonial claims of cure, on investigation, almost invariably prove due to coincidence, suggestibility, and/or the natural history of the disorder, and fall into one of the five categories of "cures that are not": The patient never had cancer. The cancer was cured or put in remission by responsible therapy, but the promoted therapy was irrelevantly also given, and is erroneously credited for the cure. The cancer is progressing silently, but erroneously represented as cured. The patient is dead, but represented as cured. The patient had a spontaneous remission, which is publicized as a "cure," while failing to publicize the hundred or more deaths per "success" which followed the same "cure." Quackery involves the consumer fraud of taking money under false pretenses. The false pretense is the promotion and selling of questionable diagnostic tests and therapies advertising them to be safe and effective.(ABSTRACT TRUNCATED AT 400 WORDS)

[Evaluating psychological injury in motor vehicle accidents (MVA): development and validation of a protocol for detecting pretense].

PubMed

Arce, Ramón; Fariña, Francisca; Carballal, Alicia; Novo, Mercedes

2006-05-01

In order to assess the feigning ability of the psychological injury in a motor vehicle accident (MVA), a total of 105 subjects, which never had suffered a serious MVA and lay in psychopathology, responded to the MMPI-2 in line with the standard instructions. Thereafter, subjects were instructed to feign moral damage generated by a MVA prior to being evaluated using a clinical-forensic interview a week later, and responding to the MMPI-2 another week later. The results show that 60.9% of the subjects were able to effectively feign moral damage on the MMPI-2, and 3.8% in the forensic clinical interview. The analysis of the instruments and procedures for the validation of subject responses i.e., the original validity control scales of the MMPI-2 and the analysis of feigning strategies in the forensic clinical interview, revealed no efficacy in feigning detection. Nevertheless, collectively, all the control measures and procedures were effective for the detection of feigning. Therefore, a protocol for the detection of feigning of moral damage has been proposed.

Dynamic and Structural Performances of a New Sailcraft Concept for Interplanetary Missions.

PubMed

Peloni, Alessandro; Barbera, Daniele; Laurenzi, Susanna; Circi, Christian

2015-01-01

Typical square solar-sail design is characterised by a central hub with four-quadrant sails, conferring to the spacecraft the classical X-configuration. One of the critical aspects related to this architecture is due to the large deformations of both membrane and booms, which leads to a reduction of the performance of the sailcraft in terms of thrust efficiency. As a consequence, stiffer sail architecture would be desirable, taking into account that the rigidity of the system strongly affects the orbital dynamics. In this paper, we propose a new solar-sail architecture, which is more rigid than the classical X-configuration. Among the main pros and cons that the proposed configuration presents, this paper aims to show the general concept, investigating the performances from the perspectives of both structural response and attitude control. Membrane deformations, structural offset, and sail vibration frequencies are determined through finite element method, adopting a variable pretensioning scheme. In order to evaluate the manoeuvring performances of this new solar-sail concept, a 35-degree manoeuvre is studied using a feedforward and feedback controller.

Doctor shopping: a concept analysis.

PubMed

Worley, Julie; Hall, Joanne M

2012-01-01

Prescription drug abuse is a significant problem in the United States that poses a serious health risk to Americans and is therefore significant to the field of nursing. The prescription drugs that are designated in the United States as having abuse potential are called controlled or scheduled drugs. The most common types of abused prescription drugs are benzodiazepines prescribed for anxiety, opioids prescribed for pain, and stimulants prescribed for attention deficit disorder. These prescription drugs are abused by taking larger doses than prescribed for nonmedical use to achieve a high or euphoric feeling, or are sold illicitly for profit. In 2009, there were 2.4 million nonmedical users of prescription opioids in the United States. These prescription drugs are often obtained by seeing multiple prescribers, often under false pretenses or with complicity from the prescribers that leads to abuse and illicit sales. The term doctor shopping has been used not only to refer to this phenomenon but has also had other meanings throughout the past decades. Thus, concept analysis is the focus of this article for clarification using the Walker and Avant method. Health implications and suggestions for minimizing doctor shopping are included.

Seatbelt use amongst taxi drivers in Beijing, China.

PubMed

Passmore, J; Ozanne-Smith, J

2006-09-01

Associated with explosive growth in motorization, China has the world's highest road toll with more than 100,000 deaths and 400,000 injuries annually. In response, the Chinese Government introduced the first road traffic safety law in 2003, which included mandatory use of seatbelts by drivers and front seat passengers. Noting frequent non-compliance to this seatbelt regulation by Beijing taxi drivers, the authors studied seatbelt use patterns as onboard observers in a convenience sample of 235 taxi trips. Findings indicated a low seatbelt-wearing rate among taxi drivers of 7.7%, an overt non-wearing rate of 57%, covert non-wearing of 35.3% and total non-compliance of 92.3%. As in high-income countries, adoption of proven safety strategies, including wearing safety restraints, could contribute to reducing the Chinese road toll, particularly as vehicle occupant numbers and the availability of restraints increases. Further investigation of reasons for non-compliance and pretense of wearing seatbelts is required to inform future seatbelt-wearing promotions, including attitudinal studies of taxi drivers. Seatbelt wearing rates should continue to be monitored.

Dynamic response of some tentative compliant wall structures to convected turbulence fields

NASA Technical Reports Server (NTRS)

Nijim, H. H.; Lin, Y. K.

1977-01-01

Some tentative compliant wall structures designed for possible skin friction drag reduction are investigated. Among the structural models considered is a ribbed membrane backed by polyurethane or PVS plastisol. This model is simplified as a beam placed on a viscoelastic foundation as well as on a set of evenly spaced supports. The total length of the beam may be either finite or infinite, and the supports may be either rigid or elastic. Another structural model considered is a membrane mounted over a series of pretensioned wires, also evenly spaced, and the entire membrane is backed by an air cavity. The forcing pressure field is idealized as a frozen random pattern convected downstream at a characteristic velocity. The results are given in terms of the frequency response functions of the system, the spectral density of the structural motion, and the spectral density of the boundary layer pressure including the effect of structural motion. These results are used in a parametric study of structural configurations capable of generating favorable wave lengths, wave amplitudes, and wave speeds in the structural motion for potential drag reduction.

The evolution of creationists in the United States: where are they now, and where are they going?

PubMed

Padian, Kevin

2009-01-01

The history of anti-evolutionism in the United States begins only in the early decades of the 20th century but has evolved considerably since then. Various versions of the movement ("equal time" for creationism, "creation science", "intelligent design") have developed over time, but they have made few positive contributions to serious discourse about science and religion. Their main goal has been to try to stop the teaching of evolution. The most recent version of creationism, "intelligent design" (ID), has little in common with William Paley's 18th-century version: ID posits an interventionist Deity who regularly interferes in natural processes to produce complex biological structures and functions. The 2005 "intelligent design" trial in Dover, Pennsylvania, destroyed any pretensions that the movement had to scientific integrity. However, anti-evolutionists continue to foment discord at local levels, where opposition to the teaching of evolution can be presented without strong resistance. Scientists can best demonstrate their concern by becoming involved in federal, state, and local administrative processes that determine curricula and develop and adopt textbooks and other instructional materials.

Modal testing of a rotating wind turbine

NASA Astrophysics Data System (ADS)

Carne, T. G.; Nord, A. R.

1982-11-01

A testing technique was developed to measure the modes of vibration of a rotating vertical-axis wind turbine. This technique was applied to the Sandia Two-Meter Turbine, where the changes in individual modal frequencies as a function of the rotational speed were tracked from 0 rpm (parked) to 600 rpm. During rotational testing, the structural response was measured using a combination of strain gages and accelerometers, passing the signals through slip rings. Excitation of the turbine structure was provided by a scheme which suddenly released a pretensioned cable, thus plucking the turbine as it was rotating at a set speed. In addition to calculating the real modes of the parked turbine, the modes of the rotating turbine were also determined at several rotational speeds. The modes of the rotating system proved to be complex due to centrifugal and Coriolis effects. The modal data for the parked turbine were used to update a finite-element model. Also, the measured modal parameters for the rotating turbine were compared to the analytical results, thus verifying the analytical procedures used to incorporate the effects of the rotating coordinate system.

Finite Element Analysis of Wrinkled Membrane Structures for Sunshield Applications

NASA Technical Reports Server (NTRS)

Johnston, John D.; Brodeur, Stephen J. (Technical Monitor)

2002-01-01

The deployable sunshield is an example of a gossamer structure envisioned for use on future space telescopes. The basic structure consists of multiple layers of pretensioned, thin-film membranes supported by deployable booms. The prediction and verification of sunshield dynamics has been identified as an area in need of technology development due to the difficulties inherent in predicting nonlinear structural behavior of the membranes and because of the challenges involved. in ground testing of the full-scale structure. This paper describes a finite element analysis of a subscale sunshield that has been subjected to ground testing in support of the Next Generation Space Telescope (NGST) program. The analysis utilizes a nonlinear material model that accounts for wrinkling of the membranes. Results are presented from a nonlinear static preloading analysis and subsequent dynamics analyses to illustrate baseline sunshield structural characteristics. Studies are then described which provide further insight into the effect of membrane. preload on sunshield dynamics and the performance of different membrane modeling techniques. Lastly, a comparison of analytical predictions and ground test results is presented.

Freedom in the free world: The extimate becomes the law.

PubMed

Aristodemou, Maria

My article takes Robert Burt's piece as a starting point to highlight how a lacanian analysis of law differs from the one Robert Burt (rightly) rejected and from the alternative psychotherapeutic scenario Burt develops. I focus on what I consider to be the novel characteristics of a lacanian analysis, particularly its insistence on the castration of the human subject by language, a castration that problematizes our understanding of "freedom" and "free speech", and, in turn, on Law's own castration. The gradual peeling away of the claims made on behalf of the subject by ego psychologists, enables us to arrive at what a lacanian analysis would ideally uncover, that is the subject's extimate core. I illustrate this with the film The Act of Killing, a documentary which displays not only the extimate core at the heart of the subject but the extimate as the Law itself. The encounter between law and psychoanalysis, I conclude, far from leading to mutual understanding, leads to the dissolution of the analysand's pretenses, and, in turn, to the withdrawal of psychoanalysis from the scene altogether. Copyright © 2016. Published by Elsevier Ltd.

Monitoring Fiber Stress During Curing of Single Fiber Glass- and Graphite-Epoxy Composites

NASA Technical Reports Server (NTRS)

Madhukar, Madhu S.; Kosuri, Ranga P.; Bowles, Kenneth J.

1994-01-01

The difference in thermal expansion characteristics of epoxy matrices and graphite fibers can produce significant residual stresses in the fibers during curing of composite materials. Tests on single fiber glass-epoxy and graphite-epoxy composite specimens were conducted in which the glass and graphite fibers were preloaded in tension, and the epoxy matrix was cast around the fibers. The fiber tension was monitored while the matrix was placed around the fiber and subjected to the temperature-time curing cycle. Two mechanisms responsible for producing stress in embedded fibers were identified as matrix thermal expansion and contraction and matrix cure shrinkage. A simple analysis based on the change in fiber tension during the curing cycle was conducted to estimate the produced stresses. Experimental results on single fiber glass- and graphite-epoxy composites show that the fiber was subjected to significant tensile stresses when the temperature was raised from the first to the second dwell period. When initial fiber pretension is about 60 percent of the fiber failure load, these curing-induced stresses can cause tensile fracture of the embedded fiber.

Freud's Little Oedipus: Hans as exception to the oedipal rule.

PubMed

Ahbel-Rappe, Karin

2008-09-01

Freud's "The Analysis of a Phobia in a Five-Year-Old Boy" is regarded by Freud and by analytic readers and commentators as a prototype of his conception of the oedipus complex. A literary methodology is used to show that the interpretation of the oedipus complex at work in Freud's text in fact differs from Freud's standard view of it. While studying the paper as text, not as case report, may obscure or distort some clinical matters, it is valuable in that it makes legible a sort of theoretical unconscious in the text. In contrast to Freud's typically tragic view of the oedipus complex (in the tradition of ancient Greek tragedy), the Hans study evokes a comic vision (in the tradition of Greek New Comedy). This comic vision allows Hans a happy imaginative ending to the oedipal dilemma, challenges certain epistemic pretensions, and emphasizes the oedipus complex as a set of abiding existential questions. Given the deep link between Freud"s oedipus concept and a tragic view of human life, this departure in the Hans paper is a fascinating anomaly.

Cancer care, money, and the value of life: whose justice? Which rationality?

PubMed

Sulmasy, Daniel P

2007-01-10

Cost-containment in oncology is a moral issue. While economists use the word "rationing" to describe all limitations on resource utilization that result from human choice, the ordinary language distinction between allocation and rationing is morally meaningful and can help oncologists to determine their proper moral role in cost-containment. It is argued that oncologists should not be required to ration at the bedside, nor should they be given financial incentives to practice frugally, nor should they be subjected to a variety of bureaucratic mechanisms to control costs indirectly. In addition, it is argued that the fact that treatments have a price does not logically imply that patients have a price. Cost-effectiveness analysis is often suggested as a means of deciding how best to allocate resources, but some of its many ethical limitations are discussed. The alternative is an open, public, participatory process about how to ration care, abandoning the formulaic pretenses of cost-effectiveness analysis, but with a commitment to reason, good will, and common sense. Oncologists would then be free to advocate for their patients within the constraints imposed by this public process.

Moral Expertise in the Clinic: Lessons Learned from Medicine and Science.

PubMed

McClimans, Leah; Slowther, Anne

2016-08-01

Philosophers and others have questioned whether or not expertise in morality is possible. This debate is not only theoretical, but also affects the perceived legitimacy of clinical ethicists. One argument against moral expertise is that in a pluralistic society with competing moral theories no one can claim expertise regarding what another ought morally to do. There are simply too many reasonable moral values and intuitions that affect theory choice and its application; expertise is epistemically uniform. In this article, we discuss how similar concerns have recently threatened to undermine expertise in medicine and science. In contrast, we argue that the application of values is needed to exercise medical, scientific, and moral expertise. As long as these values are made explicit, worries about a pretense to authority in the context of a liberal democracy are ill-conceived. In conclusion, we argue for an expertise that is epistemically diverse. © The Author 2016. Published by Oxford University Press, on behalf of the Journal of Medicine and Philosophy Inc. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Dynamic and Structural Performances of a New Sailcraft Concept for Interplanetary Missions

PubMed Central

Peloni, Alessandro; Barbera, Daniele; Laurenzi, Susanna; Circi, Christian

2015-01-01

Typical square solar-sail design is characterised by a central hub with four-quadrant sails, conferring to the spacecraft the classical X-configuration. One of the critical aspects related to this architecture is due to the large deformations of both membrane and booms, which leads to a reduction of the performance of the sailcraft in terms of thrust efficiency. As a consequence, stiffer sail architecture would be desirable, taking into account that the rigidity of the system strongly affects the orbital dynamics. In this paper, we propose a new solar-sail architecture, which is more rigid than the classical X-configuration. Among the main pros and cons that the proposed configuration presents, this paper aims to show the general concept, investigating the performances from the perspectives of both structural response and attitude control. Membrane deformations, structural offset, and sail vibration frequencies are determined through finite element method, adopting a variable pretensioning scheme. In order to evaluate the manoeuvring performances of this new solar-sail concept, a 35-degree manoeuvre is studied using a feedforward and feedback controller. PMID:26273697

Dynamic testing of a two-dimensional box truss beam

NASA Technical Reports Server (NTRS)

White, Charles W.

1987-01-01

Testing to determine the effects of joint freeplay and pretensioning of diagonal members on the dynamic characteristics of a two-dimensional box truss beam was conducted. The test article was ten bays of planar truss suspended by long wires at each joint. Each bay measured 2 meters per side. Pins of varying size were used to simulate various joint freeplay conditions. Single-point random excitation was the primary method of test. The rational fraction polynomial method was used to extract modal characteristics from test data. A finite element model of the test article was generated from which modal characteristics were predicted. These were compared with those obtained from tests. With the exception of the fundamental mode, correlation of theoretical and experimental results was poor, caused by the resonant coupling of local truss member bending modes with global truss beam modes. This coupling introduced many modes in the frequency range of interest whose frequencies were sensitive to joint boundary conditions. It was concluded that local/global coupling must be avoided in the frequency range where accurate modal characteristics are required.

Study on the Old Girders in the Widening Hollow Slab Girder Bridge

NASA Astrophysics Data System (ADS)

Wang, Ying; Zhang, Li Fang; Ma, Hai Yan

2018-06-01

Taking the bridge widening project of Shanghai-Hangzhou-Ningbo expressway widening construction project (China) as the background in this paper, the variation law of the internal force of the old bridge in the widening hollow slab girder bridge under vehicle load is studied, which is under the condition of different span lengths and different widening widths. Three different span lengths of the pre-tensioned prestressed hollow slab girder bridges are selected, the spatial finite element models of both the old bridge and the whole structure of widening bridge are established and calculated respectively by Midas/Civil software. The influences of widening and load increasing on the old bridges under the vehicle load are compared and analyzed. In addition, the authors also analyze the influences of different widening widths on the force state of old bridges under the condition of widening the same number of lane. Moreover , the effects on the old bridges that are caused by the uneven foundation settlement of widening bridge structure are also studied in this paper. This paper can provide some references for widening design of hollow slab bridges.

Mechanical Design of HD2, a 15 T Nb3Sn Dipole Magnet with a 35 mm Bore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferracin, P.; Bartlett, S.E.; Caspi, S.

2006-06-01

After the fabrication and test of HD1, a 16 T Nb{sub 3}Sn dipole magnet based on flat racetrack coil configuration, the Superconducting Magnet Program at Lawrence Berkeley National Laboratory (LBNL) is developing the Nb{sub 3}Sn dipole HD2. With a dipole field above 15 T, a 35 mm clear bore, and nominal field harmonics within a fraction of one unit, HD2 represents a further step towards the application of block-type coils to high-field accelerator magnets. The design features tilted racetrack-type ends, to avoid obstructing the beam path, and a 4 mm thick stainless steel tube, to support the coil during themore » preloading operation. The mechanical structure, similar to the one used for HD1, is based on an external aluminum shell pretensioned with pressurized bladders. Axial rods and stainless steel plates provide longitudinal support to the coil ends during magnet excitation. A 3D finite element analysis has been performed to evaluate stresses and deformations from assembly to excitation, with particular emphasis on conductor displacements due to Lorentz forces. Numerical results are presented and discussed.« less

Mechanical qualification of the support structure for MQXF, the Nb 3Sn low-β quadrupole for the high luminosity LHC

DOE PAGES

Juchno, M.; Ambrosio, G.; Anerella, M.; ...

2016-01-26

Within the scope of the High Luminosity LHC project, the collaboration between CERN and U.S. LARP is developing new low-β quadrupoles using the Nb 3Sn superconducting technology for the upgrade of the LHC interaction regions. The magnet support structure of the first short model was designed and two units were fabricated and tested at CERN and at LBNL. The structure provides the preload to the collars-coils subassembly by an arrangement of outer aluminum shells pre-tensioned with water-pressurized bladders. For the mechanical qualification of the structure and the assembly procedure, superconducting coils were replaced with solid aluminum “dummy coils”, the structuremore » was preloaded at room temperature, and then cooled-down to 77 K. Mechanical behavior of the magnet structure was monitored with the use of strain gauges installed on the aluminum shells, the dummy coils and the axial preload system. As a result, this paper reports on the outcome of the assembly and the cool-down tests with dummy coils, which were performed at CERN and at LBNL, and presents the strain gauge measurements compared to the 3D finite element model predictions.« less

Modeling and Analysis of Structural Dynamics for a One-Tenth Scale Model NGST Sunshield

NASA Technical Reports Server (NTRS)

Johnston, John; Lienard, Sebastien; Brodeur, Steve (Technical Monitor)

2001-01-01

New modeling and analysis techniques have been developed for predicting the dynamic behavior of the Next Generation Space Telescope (NGST) sunshield. The sunshield consists of multiple layers of pretensioned, thin-film membranes supported by deployable booms. Modeling the structural dynamic behavior of the sunshield is a challenging aspect of the problem due to the effects of membrane wrinkling. A finite element model of the sunshield was developed using an approximate engineering approach, the cable network method, to account for membrane wrinkling effects. Ground testing of a one-tenth scale model of the NGST sunshield were carried out to provide data for validating the analytical model. A series of analyses were performed to predict the behavior of the sunshield under the ground test conditions. Modal analyses were performed to predict the frequencies and mode shapes of the test article and transient response analyses were completed to simulate impulse excitation tests. Comparison was made between analytical predictions and test measurements for the dynamic behavior of the sunshield. In general, the results show good agreement with the analytical model correctly predicting the approximate frequency and mode shapes for the significant structural modes.

Phytotoxic property of the invasive plant Tithonia diversifolia and a phytotoxic substance.

PubMed

Suzuki, Masahiko; Iwasaki, Arihiro; Suenaga, Kiyotake; Kato-Noguchi, Hisashi

2017-06-01

Tithonia diversifolia (Hermsl.) A. Gray is a perennial invasive plant and spreads quickly in the invasive areas. The extracts of T. diversifolia were found to be toxic to several crop plant species such as rice, maize, sorghum, lettuce and cowpea, and several putative allelopathic substances were identified. However, there is limited information available for the effects of T. diversifolia on wild plants including weed plant species. We investigated the allelopathic potential of T. diversifolia extracts on weed plants, and searched for phytotoxic substances with allelopathic activity. An aqueous methanol extract of T. diversifolia leaves inhibited the growth of weed plants, Lolium multiflorum Lam., Phleum pretense L., Echinochloa crus-galli (L.) Beauv. The extract was then purified by several chromatographic runs and a phytotoxic substance with allelopathic activity was isolated and identified by spectral analysis as tagitinin C. The substance inhibited the growth of Lolium multiflorum, Phleum pratense and Echinochloa crus-galli at concentrations greater than 0.1 - 0.3 mM. The present results suggest that T. diversifolia may possess allelopathic potential on weed plants and tagitinin C may be responsible for the allelopathic effects of T. diversifolia. The allelopathic potential of T. diversifolia may contribute to its invasive characteristics.

Unsteady aerodynamics of membrane wings with adaptive compliance

NASA Astrophysics Data System (ADS)

Kiser, Jillian; Breuer, Kenneth

2016-11-01

Membrane wings are known to provide superior aerodynamic performance at low Reynolds numbers (Re =104 -105), primarily due to passive shape adaptation to flow conditions. In addition to this passive deformation, active control of the fluid-structure interaction and resultant aerodynamic properties can be achieved through the use of dielectric elastomer actuators as the wing membrane material. When actuated, membrane pretension is decreased and wing camber increases. Additionally, actuation at resonance frequencies allows additional control over wing camber. We present results using synchronized (i) time-resolved particle image velocimetry (PIV) to resolve the flow field, (ii) 3D direct linear transformation (DLT) to recover membrane shape, (iii) lift/drag/torque measurements and (iv) near-wake hot wire anemometry measurements to characterize the fluid-structure interactions. Particular attention is paid to cases in which the vortex shedding frequency, the membrane resonance, and the actuation frequency coincide. In quantitatively examining both flow field and membrane shape at a range of actuation frequencies and vortex shedding frequencies, this work seeks to find actuation parameters that allow for active control of boundary layer separation over a range of flow conditions. Also at Naval Undersea Warfare Center, Division Newport.

Numerical Simulation of the Self-Oscillations of the Vocal Folds and of the Resulting Acoustic Phenomena in the Vocal Tract

NASA Astrophysics Data System (ADS)

Švancara, P.; Horáček, J.; Švec, J. G.

The study presents a three-dimensional (3D) finite element (FE) model of the flow-induced self-oscillation of the human vocal folds in interaction with acoustics of simplified vocal tract models. The 3D vocal tract models of the acoustic spaces shaped for simulation of phonation of Czech vowels [a:], [i:] and [u:] were created by converting the data from the magnetic resonance images (MRI). For modelling of the fluid-structure interaction, explicit coupling scheme with separated solvers for fluid and structure domain was utilized. The FE model comprises vocal folds pretension before starting phonation, large deformations of the vocal fold tissue, vocal-fold collisions, fluid-structure interaction, morphing the fluid mesh according to the vocal-fold motion (Arbitrary Lagrangian-Eulerian approach), unsteady viscous compressible airflow described by the Navier-Stokes equations and airflow separation. The developed FE model enables to study the relationship between flow-induced vibrations of the vocal folds and acoustic wave propagation in the vocal tract and can also be used to simulate for example pathological changes in the vocal fold tissue and their influence on the voice production.

Solar Sail Topology Variations Due to On-Orbit Thermal Effects

NASA Technical Reports Server (NTRS)

Banik, Jeremy A.; Lively, Peter S.; Taleghani, Barmac K.; Jenkins, Chrostopher H.

2006-01-01

The objective of this research was to predict the influence of non-uniform temperature distribution on solar sail topology and the effect of such topology variations on sail performance (thrust, torque). Specifically considered were the thermal effects due to on orbit attitude control maneuvers. Such maneuvers are expected to advance the sail to a position off-normal to the sun by as much as 35 degrees; a solar sail initially deformed by typical pre-tension and solar pressure loads may suffer significant thermally induced strains due to the non-uniform heating caused by these maneuvers. This on-orbit scenario was investigated through development of an automated analytical shape model that iterates many times between sail shape and sail temperature distribution before converging on a final coupled thermal structural affected sail topology. This model utilizes a validated geometrically non-linear finite element model and a thermal radiation subroutine. It was discovered that temperature gradients were deterministic for the off-normal solar angle cases as were thermally induced strains. Performance effects were found to be moderately significant but not as large as initially suspected. A roll torque was detected, and the sail center of pressure shifted by a distance that may influence on-orbit sail control stability.

A New Multiconstraint Method for Determining the Optimal Cable Stresses in Cable-Stayed Bridges

PubMed Central

Asgari, B.; Osman, S. A.; Adnan, A.

2014-01-01

Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method. PMID:25050400

Nonlinear modelling of high-speed catenary based on analytical expressions of cable and truss elements

NASA Astrophysics Data System (ADS)

Song, Yang; Liu, Zhigang; Wang, Hongrui; Lu, Xiaobing; Zhang, Jing

2015-10-01

Due to the intrinsic nonlinear characteristics and complex structure of the high-speed catenary system, a modelling method is proposed based on the analytical expressions of nonlinear cable and truss elements. The calculation procedure for solving the initial equilibrium state is proposed based on the Newton-Raphson iteration method. The deformed configuration of the catenary system as well as the initial length of each wire can be calculated. Its accuracy and validity of computing the initial equilibrium state are verified by comparison with the separate model method, absolute nodal coordinate formulation and other methods in the previous literatures. Then, the proposed model is combined with a lumped pantograph model and a dynamic simulation procedure is proposed. The accuracy is guaranteed by the multiple iterative calculations in each time step. The dynamic performance of the proposed model is validated by comparison with EN 50318, the results of the finite element method software and SIEMENS simulation report, respectively. At last, the influence of the catenary design parameters (such as the reserved sag and pre-tension) on the dynamic performance is preliminarily analysed by using the proposed model.

Seatbelt and seatback control for occupant protection in frontal automotive collisions

NASA Astrophysics Data System (ADS)

Mott, Michael; Sun, Zhen; Rajamani, Rajesh

2013-10-01

This paper investigates the potential benefits of an imminent collision prediction system for improving occupant protection in a frontal automotive crash. Knowledge of an impending unavoidable crash is assumed to be known 100 ms before the crash occurs. A three dof human occupant model is developed using a Lagrangian approach to represent occupant translation with respect to seat, torso rotation and neck rotation. The performance of traditional elastic seat belts is compared with that of an analytically calculated seat belt law in which the force values are calculated in real-time so as to just prevent collision with car interior. Simulations verify that the analytical seat belt force calculation results in less force on occupant for the same level of safety. Furthermore, results show that knowledge of a future collision can be used to pre-tension seat belts but can provide no additional benefits, if seat belts are the only means for active occupant protection. However, if seat tilt-back can be deployed using an on-off mechanism, such predictive knowledge of a future collision can provide significantly improved occupant protection in terms of preventing occupant collision with car interior.

Damage location and quantification of a pretensioned concrete beam using stochastic subspace identification

NASA Astrophysics Data System (ADS)

Cancelli, Alessandro; Micheli, Laura; Laflamme, Simon; Alipour, Alice; Sritharan, Sri; Ubertini, Filippo

2017-04-01

Stochastic subspace identification (SSID) is a first-order linear system identification technique enabling modal analysis through the time domain. Research in the field of structural health monitoring has demonstrated that SSID can be used to successfully retrieve modal properties, including modal damping ratios, using output-only measurements. In this paper, the utilization of SSID for indirectly retrieving structures' stiffness matrix was investigated, through the study of a simply supported reinforced concrete beam subjected to dynamic loads. Hence, by introducing a physical model of the structure, a second-order identification method is achieved. The reconstruction is based on system condensation methods, which enables calculation of reduced order stiffness, damping, and mass matrices for the structural system. The methods compute the reduced order matrices directly from the modal properties, obtained through the use of SSID. Lastly, the reduced properties of the system are used to reconstruct the stiffness matrix of the beam. The proposed approach is first verified through numerical simulations and then validated using experimental data obtained from a full-scale reinforced concrete beam that experienced progressive damage. Results show that the SSID technique can be used to diagnose, locate, and quantify damage through the reconstruction of the stiffness matrix.

A new multiconstraint method for determining the optimal cable stresses in cable-stayed bridges.

PubMed

Asgari, B; Osman, S A; Adnan, A

2014-01-01

Cable-stayed bridges are one of the most popular types of long-span bridges. The structural behaviour of cable-stayed bridges is sensitive to the load distribution between the girder, pylons, and cables. The determination of pretensioning cable stresses is critical in the cable-stayed bridge design procedure. By finding the optimum stresses in cables, the load and moment distribution of the bridge can be improved. In recent years, different research works have studied iterative and modern methods to find optimum stresses of cables. However, most of the proposed methods have limitations in optimising the structural performance of cable-stayed bridges. This paper presents a multiconstraint optimisation method to specify the optimum cable forces in cable-stayed bridges. The proposed optimisation method produces less bending moments and stresses in the bridge members and requires shorter simulation time than other proposed methods. The results of comparative study show that the proposed method is more successful in restricting the deck and pylon displacements and providing uniform deck moment distribution than unit load method (ULM). The final design of cable-stayed bridges can be optimised considerably through proposed multiconstraint optimisation method.

Safe Local Navigation for Visually Impaired Users With a Time-of-Flight and Haptic Feedback Device.

PubMed

Katzschmann, Robert K; Araki, Brandon; Rus, Daniela

2018-03-01

This paper presents ALVU (Array of Lidars and Vibrotactile Units), a contactless, intuitive, hands-free, and discreet wearable device that allows visually impaired users to detect low- and high-hanging obstacles, as well as physical boundaries in their immediate environment. The solution allows for safe local navigation in both confined and open spaces by enabling the user to distinguish free space from obstacles. The device presented is composed of two parts: a sensor belt and a haptic strap. The sensor belt is an array of time-of-flight distance sensors worn around the front of a user's waist, and the pulses of infrared light provide reliable and accurate measurements of the distances between the user and surrounding obstacles or surfaces. The haptic strap communicates the measured distances through an array of vibratory motors worn around the user's upper abdomen, providing haptic feedback. The linear vibration motors are combined with a point-loaded pretensioned applicator to transmit isolated vibrations to the user. We validated the device's capability in an extensive user study entailing 162 trials with 12 blind users. Users wearing the device successfully walked through hallways, avoided obstacles, and detected staircases.

Johann Bernhard Aloys von Gudden and the Mad King of Bavaria

PubMed Central

Bhattacharyya, Kalyan B.

2017-01-01

Bernhard von Gudden was a psychiatrist in Prussia and he was summoned in March 1886 to examine King Ludwig II for his apparently insane activities like, profligate spending and erratic behaviour. A team of four estimable psychiatrists pronounced that he was not capable ruling. Consequently, he was dethroned and kept in a castle under supervision of von Gudden. Gudden championed the idea of 'no restraint' and advocated free movement of insane persons and one evening in June, he accompanied the King during an evening stroll to a lake. A few hours later, the corpus of both of them were recovered under mysterious circumstances. Autopsy suggested that the King was drowned but no post-mortem examination was performed on von Gudden. There are plenty of controversies regarding their death like, murder, accidental death or even natural death from cardiac arrest following immersion in cold water, but no incontrovertible conclusion could be arrived at, even after scrupulous analysis by historians and even the diagnosis of insanity of the King has been doubted. Some even suggested that the opinion of psychiatrists were sought as a pretense in order to depose the King. PMID:29184335

The skin prick test – European standards

PubMed Central

2013-01-01

Skin prick testing is an essential test procedure to confirm sensitization in IgE-mediated allergic disease in subjects with rhinoconjunctivitis, asthma, urticaria, anapylaxis, atopic eczema and food and drug allergy. This manuscript reviews the available evidence including Medline and Embase searches, abstracts of international allergy meetings and position papers from the world allergy literature. The recommended method of prick testing includes the appropriate use of specific allergen extracts, positive and negative controls, interpretation of the tests after 15 – 20 minutes of application, with a positive result defined as a wheal ≥3 mm diameter. A standard prick test panel for Europe for inhalants is proposed and includes hazel (Corylus avellana), alder (Alnus incana), birch (Betula alba), plane (Platanus vulgaris), cypress (Cupressus sempervirens), grass mix (Poa pratensis, Dactilis glomerata, Lolium perenne, Phleum pratense, Festuca pratensis, Helictotrichon pretense), Olive (Olea europaea), mugwort (Artemisia vulgaris), ragweed (Ambrosia artemisiifolia), Alternaria alternata (tenuis), Cladosporium herbarum, Aspergillus fumigatus, Parietaria, cat, dog, Dermatophagoides pteronyssinus, Dermatophagoides farinae, and cockroach (Blatella germanica). Standardization of the skin test procedures and standard panels for different geographic locations are encouraged worldwide to permit better comparisons for diagnostic, clinical and research purposes. PMID:23369181

Experimental and numerical study of Bondura® 6.6 PIN joints

NASA Astrophysics Data System (ADS)

Berkani, I.; Karlsen, Ø.; Lemu, H. G.

2017-12-01

Pin joints are widely used in heavy-duty machinery such as aircrafts, cranes and offshore drilling equipment to transfer multi-dimensional shear forces. Their strength and service life depend on the clamping force in the contact region that is provided by interference fits. Though the interference fits provide full contact at the pin-hole interface under pretension loads, the contact interface reduces when the pin is subjected to an external load and hence a smaller contact surface leads to dramatic increase of the contact stress. The PIN joint of Bondura® Technology, investigated in this study, is an innovative solution intended to reduce the slack at the contact surface of the pin joint of heavy-duty machinery by using tapered sleeves on each end of the PIN. The study is aimed to better understand the contact pressure build-up and stress distribution in the supporting contact surface under pre-loading of the joint and the influence of temperature difference between part assembly and operation conditions. Numerical simulation using finite element method and diverse experimental tests were conducted. The numerical simulation and the test results, particularly the tests conducted with lubricated joints, show good conformance.

Evaluation of 5 knots and 2 suture materials for arthroscopic rotator cuff repair: very strong sutures can still slip.

PubMed

Abbi, Gaurav; Espinoza, Luis; Odell, Timothy; Mahar, Andrew; Pedowitz, Robert

2006-01-01

To compare a standard suture material with a newer material using multiple arthroscopic knot configurations and to evaluate the biomechanical performance of a new sliding-locking knot compared with 4 surgical standards. Controlled laboratory study. Five knots were evaluated (Weston, Tennessee, Duncan, SMC, and the new San Diego knot) using 2 suture materials, No. 2 Ethibond (Ethicon, Somerville, NJ) or No. 2 Fiberwire (Arthrex, Naples, FL). Eight samples were tested for each knot-suture configuration. Samples were pretensioned to 10 N and then loaded from 10 to 45 N for 1,000 cycles. Intact knots were loaded to failure. Fiberwire had significantly higher load-to-failure (276 +/- 24 N) compared with Ethibond (111 +/- 13 N) (P < .001), although there was no significant difference as a function of knot configuration. Of the 40 Fiberwire knots, 3 failed by early slippage during cyclic loading and 8 slipped at very low tension during load-to-failure. None of the Ethibond knots and none of the San Diego knots failed by early slippage. Surface characteristics and suture construction affect the tendency for knot slippage. Surgeons should understand the impact of handling characteristics, frictional properties, and ultimate failure load when selecting suture materials and knots for arthroscopic repair.

Distributed microscopic actuation analysis of deformable plate membrane mirrors

NASA Astrophysics Data System (ADS)

Lu, Yifan; Yue, Honghao; Deng, Zongquan; Tzou, Hornsen

2018-02-01

To further reduce the areal density of optical mirrors used in space telescopes and other space-borne optical structures, the concept of flexible membrane deformable mirror has been proposed. Because of their high flexibility, poor stiffness and low damping properties, environmental excitations such as orbital maneuver, path changing, and non-uniform heating may induce unexpected vibrations and thus reduce working performance. Therefore, active vibration control is essential for these membrane mirrors. In this paper, two different mirror models, i.e., the plate membrane model and pure membrane model, are studied respectively. In order to investigate the modal vibration characteristics of the mirror, a piezoelectric layer is fully laminated on its non-reflective side to serve as actuators. Dynamic equations of the mirror laminated with piezoelectric actuators are presented first. Then, the actuator induced modal control force is defined. When the actuator area shrinks to infinitesimal, the expressions of microscopic local modal control force and its two components are obtained to predict the spatial microscopic actuation behavior of the mirror. Different membrane pretension forces are also applied to reveal the tension effects on the actuation of the mirror. Analyses indicate that the spatial distribution of modal micro-control forces is exactly the same with the sensing signals distribution of the mirror, which provides crucial guidelines for optimal actuator placement of membrane deformable mirrors.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Bo; Nelson, Kevin; Lipinski, Ronald

In this study, conventional Kolsky tension bar techniques were modified to characterize an iridium alloy in tension at elevated strain rates and temperatures. The specimen was heated to elevated temperatures with an induction coil heater before dynamic loading; whereas, a cooling system was applied to keep the bars at room temperature during heating. A preload system was developed to generate a small pretension load in the bar system during heating in order to compensate for the effect of thermal expansion generated in the high-temperature tensile specimen. A laser system was applied to directly measure the displacements at both ends ofmore » the tensile specimen in order to calculate the strain in the specimen. A pair of high-sensitivity semiconductor strain gages was used to measure the weak transmitted force due to the low flow stress in the thin specimen at elevated temperatures. The dynamic high-temperature tensile stress–strain curves of a DOP-26 iridium alloy were experimentally obtained at two different strain rates (~1000 and 3000 s -1) and temperatures (~750 and 1030°C). The effects of strain rate and temperature on the tensile stress–strain response of the iridium alloy were determined. Finally, the iridium alloy exhibited high ductility in stress–strain response that strongly depended on strain-rate and temperature.« less

Numerical Assessment of the Role of Slip and Twinning in Magnesium Alloy AZ31B During Loading Path Reversal

NASA Astrophysics Data System (ADS)

Wang, Huamiao; Wu, Peidong; Wang, Jian

2015-07-01

Magnesium alloy AZ31B plastically deforms via twinning and slip. Corresponding to the unidirectional nature of twinning, the activity of twinning/detwinning is directly related to loading history and materials texture. Using the elastic viscoplastic self-consistent model implementing with the twinning and detwinning model (EVPSC-TDT), we revisited experimental data of AZ31B sheets under four different strain paths: (1) tension-compression-tension along rolling direction, (2) tension-compression-tension along transverse direction, (3) compression-tension-compression along rolling direction, and (4) compression-tension-compression along transverse direction, and identified the dominant deformation mechanisms with respect to the strain path. We captured plastic deformation behaviors observed in experiments and quantitatively interpreted experimental observations in terms of the activities of different deformation mechanisms and the evolution of texture. It is found that the in-plane pre-tension has slight effect on the subsequent deformation, and the pre-compression and the reverse tension after compression have significant effect on the subsequent deformation. The inelastic behavior under compressive unloading is found to be insignificant at a small strain level but pronounced at a large strain level. Such significant effect is mainly ascribed to the activity of twinning and detwinning.

Anatomy of deception: a behavioral contingency analysis.

PubMed

Mechner, Francis

2010-05-01

Deception, a basic and pervasive biological phenomenon, takes many forms, variously referred to as mimicry, trickery, seduction, pretense, feigning, masquerading, impersonation, distraction, or false promises, and these share certain common distinguishing behavioral elements that permit them to be classified into categories. A symbolic language for the codification and analysis of behavioral contingencies shows that all instances of deception are based on a misperception, misprediction, non-perception, or non-prediction by the deceived party, and can be further categorized based on features of the contingencies that define them. Instances of particular interest are those in which a deceiving party predicts (and in that sense "intends") the deception. In those instances, the effect of the deception is usually to the deceiving party's benefit and to the deceived party's detriment. In economics, finance, business, military operations, public affairs, education, and everyday social interaction, deception takes numerous forms. Special forms, usually involving obfuscation, concealment, counterfeiting, and misrepresentation, occur in certain prevalent types of property transfer, including securitization, the creation of derivatives, and various types of Ponzi schemes. Such property transfers tend to be driven by opportunities for deception. They all involve blurring and clouding of the contingencies that defined the transferred properties, thus permitting their obfuscation. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Definitions of love in a sample of British women: an empirical study using Q methodology.

PubMed

Watts, Simon; Stenner, Paul

2014-09-01

Social psychological research has increasingly acknowledged that any pretensions to a singular theory of love should be replaced with a concern about its affirmation and what people actually say and do in love's name. Lee's (1977) love styles research and Sternberg's (1995) theory of love as a story are prime examples. Despite traditional definitions of love in western cultures being dominated by feminine images and tales of gender difference, however, the personal definitions and experiences of women have received comparatively little empirical attention, particularly in recent years and despite some well-documented changes in their cultural circumstances. This study remedies that situation through presentation of a Q methodological study in which a convenience sample of 59 British women were asked to Q sort 54 single-word descriptors of love to define love as they had experienced it. Factor analysis of the resulting Q sorts revealed six distinct definitions of love, interpreted as 'attraction, passion & romance', 'unconditional love', 'sex & fun', 'friendship & spirituality', 'a permanent commitment', and 'separate people, separate lives'. The six definitions are then discussed in terms of their allegiance to traditionally feminine and/or masculine values and as a means of highlighting the changing face of Britain's relational culture. © 2013 The British Psychological Society.

Stochastic unilateral free vibration of an in-plane cable network

NASA Astrophysics Data System (ADS)

Giaccu, Gian Felice; Barbiellini, Bernardo; Caracoglia, Luca

2015-03-01

Cross-ties are often used on cable-stayed bridges for mitigating wind-induced stay vibration since they can be easily installed on existing systems. The system obtained by connecting two (or more) stays with a transverse restrainer is designated as an "in-plane cable-network". Failures in the restrainers of an existing network have been observed. In a previous study [1] a model was proposed to explain the failures in the cross-ties as being related to a loss in the initial pre-tensioning force imparted to the connector. This effect leads to the "unilateral" free vibration of the network. Deterministic free vibrations of a three-cable network were investigated by using the "equivalent linearization method". Since the value of the initial vibration amplitude is often not well known due to the complex aeroelastic vibration regimes, which can be experienced by the stays, the stochastic nature of the problem must be considered. This issue is investigated in the present paper. Free-vibration dynamics of the cable network, driven by an initial stochastic disturbance associated with uncertain vibration amplitudes, is examined. The corresponding random eigen-value problem for the vibration frequencies is solved through an implementation of Stochastic Approximation, (SA) based on the Robbins-Monro Theorem. Monte-Carlo methods are also used for validating the SA results.

Critical current degradation behaviour of GdBCO CC tapes in pure torsion and combined tension-torsion modes

NASA Astrophysics Data System (ADS)

Gorospe, Alking; Bautista, Zhierwinjay; Shin, Hyung-Seop

2016-10-01

Coated conductor (CC) tapes utilized in high-current-density superconducting cables are commonly subjected to different loading modes, primarily torsion and tension especially in the case of twisted stacked-tape cable. Torsion load can occur due to twisting along the length or when winding the CC tapes around a former, while tension load can occur due to pre-tension when coiled and as a hoop stress when the coil is energized. In this study, electromechanical properties of single CC tapes under torsion load were investigated using a new test apparatus. The results could provide basic information for cable designers to fully characterize stacked cables. Copper-electroplated and brass-laminated CC tapes fabricated with different deposition techniques were subjected to pure torsion and combined tension-torsion loading. The critical current, I c degradation behaviours of CC tapes under torsional deformation were examined. Also, the effect of further external lamination on the I c degradation behaviour of the CC tapes under such loading conditions was investigated. In the case of the combined tension-torsion test, short samples were subjected to twist pitches of 200 mm and 100 mm. Critical parameters including reversible axial stress and strain in such twist pitch conditions were also investigated.

European attitudes on the regulation of modern biotechnology and their consequences.

PubMed

Cantley, Mark

2012-01-01

Modern biotechnology has gradually attracted ever greater interest over the past four decades, from ever-widening communities across the world--from academic scientists, of course, and then from industrialists, journalists, medical specialists, agricultural practitioners, environmental "experts," economists, trading companies--and, so far as it concerns regulation, above all from political interests whose product is indeed legislation. As the interests widened, conflicts developed: between departments, between sectors, between countries and between international agencies. The European Community made choices, bitterly contested; the battles on conducting and regulating the field release of GMOs (genetically modified organisms) were usually won--at least in Europe--by the environment ministries, often in conflict with agriculture and/or the research and science ministries. The result has been the construction over the past 30 y of an ever heavier regulatory burden on those who seek to develop and launch products based on the use of modern biotechnology. The pretense is labeled "the precautionary principle." No lives have been saved, but many jobs have been created in bureaucracies large and small around the world. So far as academia was concerned, their experiments and field trials were repeatedly wrecked by NGOs (non-governmental organizations) claiming thus to have saved mankind and the environment. This is a story of grave political failure in Europe with globally adverse consequences.

Plant quality and conspecific density effects on Anaphothrips obscurus (Thysanoptera: Thripidae) wing diphenism and population ecology.

PubMed

Reisig, Dominic D; Godfrey, Larry D; Marcum, Daniel B

2010-04-01

Factors that influence thysanopteran wing diphenism are not well known. In these studies, the impact of food quality, mediated through nitrogen addition, and conspecific density was explored on the wing diphenism of an herbivorous thrips species (Anaphothrips obscurus Müller) (Thysanoptera: Thripidae). In the first study, nitrogen was added to timothy grass (Phleum pretense L.) (Poales: Poaceae) transplants, and naturally occurring thrips populations were caged on the plants. Thrips abundance and foliar nutrients were assessed every 2 wk. A separate factorial experiment in growth chambers explored the impact of both plant nitrogen addition and thrips abundance on wing diphenism. Thrips density was manipulated by adding either 3 or 40 thrips to potted and caged timothy. Thrips abundance and foliar nutrients were measured 58 d after treatment placement. Plant quality directly affected thrips wing diphenism independent of thrips density in both experiments. Near the end of the field cage experiment, density may have indirectly impacted wing diphenism. In both experiments, plant quality and thrips density interacted to affect thrips population abundance. Plant quality alone can affect thrips wing diphenism, but it remains unclear whether density alone can affect thrips wing diphenism. This is a unique and understudied system that will be useful to examine generalized theories on the negative interaction between reproduction and dispersal.

Corner Wrinkling at a Square Membrane Due to Symmetric Mechanical Loads

NASA Technical Reports Server (NTRS)

Blandino, Joseph R.; Johnston, John D.; Dharamsi, Urmil K.; Brodeur, Stephen J. (Technical Monitor)

2001-01-01

Thin-film membrane structures are under consideration for use in many future gossamer spacecraft systems. Examples include sunshields for large aperture telescopes, solar sails, and membrane optics. The development of capabilities for testing and analyzing pre-tensioned, thin film membrane structures is an important and challenging aspect of gossamer spacecraft technology development. This paper presents results from experimental and computational studies performed to characterize the wrinkling behavior of thin-fi[m membranes under mechanical loading. The test article is a 500 mm square membrane subjected to symmetric comer loads. Data is presented for loads ranging from 0.49 N to 4.91 N. The experimental results show that as the load increases the number of wrinkles increases, while the wrinkle amplitude decreases. The computational model uses a finite element implementation of Stein-Hedgepeth membrane wrinkling theory to predict the behavior of the membrane. Comparisons were made with experimental results for the wrinkle angle and wrinkled region. There was reasonably good agreement between the measured wrinkle angle and the predicted directions of the major principle stresses. The shape of the wrinkle region predicted by the finite element model matches that observed in the experiments; however, the size of the predicted region is smaller than that determined in the experiments.

Numerical assessment of the role of slip and twinning in magnesium alloy AZ31B during loading path reversal

DOE PAGES

Wang, Huamiao; Wu, Peidong; Wang, Jian

2015-04-17

Magnesium alloy AZ31B plastically deforms via twinning and slip. Corresponding to the unidirectional nature of twinning, the activity of twinning/detwinning is directly related to loading history and materials texture. Using the elastic viscoplastic self-consistent model implementing with the twinning and detwinning model (EVPSC–TDT), we revisited experimental data of AZ31B sheets under four different strain paths: (1) tension–compression–tension along rolling direction, (2) tension–compression–tension along transverse direction, (3) compression–tension–compression along rolling direction, and (4) compression–tension–compression along transverse direction, and identified the dominant deformation mechanisms with respect to the strain path. We captured plastic deformation behaviors observed in experiments and quantitatively interpreted experimentalmore » observations in terms of the activities of different deformation mechanisms and the evolution of texture. It is found that the in-plane pre-tension has slight effect on the subsequent deformation, and the pre-compression and the reverse tension after compression have significant effect on the subsequent deformation. The inelastic behavior under compressive unloading is found to be insignificant at a small strain level but pronounced at a large strain level. Lastly, such significant effect is mainly ascribed to the activity of twinning and detwinning.« less

The ESA/MBB unfurlable mesh antenna development for mobile services

NASA Astrophysics Data System (ADS)

Kellermeier, H.; Vorbrugg, H.; Pontoppidan, K.; Eaton, D. C. G.

Mobile services via satellite in the 800-900 MHz frequency range have recently been studied by SPAR Aerospace Ltd in the M-SAT phase B using various unfurlable offset reflector concepts between 9 and 5 m aperture diameters for 6-, 4- and 2-beam coverage. For a 2-beam coverage of Canada and U.S.A. two offset antennas each of 5 m aperture diameter are required. The MBB offset unfurlable mesh antenna (UMA) developed since 1983 under an ESA contract is one of the attractive candidates: The design concept chosen uses foldable radial ribs of carbon fibre which deploy a gold plated molybdenum mesh on adjustable stand-offs. This concept is applicable for offset aperture diameters up to 12 m since the carbon fibre ribs are double folded and provide for a high package density when stowed at the spacecraft during launch. The electrical analysis performed by TICRA/Copenhagen was assisted by electrical measurements on mesh samples, verifying that main charactertics as ohmic resistance, transmission loss and passive intermodulation products (PIMP) lie within the required tolerances if the mesh is pretensioned to a certain configuration. For on-orbit testing and retrieval by the Shuttle the reflector shows a unique design feature of retractability by the reversable deployment sequence.

Behaviour of concrete beams reinforced withFRP prestressed concrete prisms

NASA Astrophysics Data System (ADS)

Svecova, Dagmar

The use of fibre reinforced plastics (FRP) to reinforce concrete is gaining acceptance. However, due to the relatively low modulus of FRP, in comparison to steel, such structures may, if sufficient amount of reinforcement is not used, suffer from large deformations and wide cracks. FRP is generally more suited for prestressing. Since it is not feasible to prestress all concrete structures to eliminate the large deflections of FRP reinforced concrete flexural members, researchers are focusing on other strategies. A simple method for avoiding excessive deflections is to provide sufficiently high amount of FRP reinforcement to limit its stress (strain) to acceptable levels under service loads. This approach will not be able to take advantage of the high strength of FRP and will be generally uneconomical. The current investigation focuses on the feasibility of an alternative strategy. This thesis deals with the flexural and shear behaviour of concrete beams reinforced with FRP prestressed concrete prisms. FRP prestressed concrete prisms (PCP) are new reinforcing bars, made by pretensioning FRP and embedding it in high strength grout/concrete. The purpose of the research is to investigate the feasibility of using such pretensioned rebars, and their effect on the flexural and shear behaviour of reinforced concrete beams over the entire loading range. Due to the prestress in the prisms, deflection of concrete beams reinforced with this product is substantially reduced, and is comparable to similarly steel reinforced beams. The thesis comprises both theoretical and experimental investigations. In the experimental part, nine beams reinforced with FRP prestressed concrete prisms, and two companion beams, one steel and one FRP reinforced were tested. All the beams were designed to carry the same ultimate moment. Excellent flexural and shear behaviour of beams reinforced with higher prestressed prisms is reported. When comparing deflections of three beams designed to have the same ultimate capacity, but reinforced with either steel, PCP or FRP rebars, the service load deflections of beams reinforced with PCP are comparable to that of a steel reinforced concrete beam, and are four times smaller than the deflection of the companion FRP reinforced beam. Similarly, the crack width of the PCP reinforced beams under service loads is comparable to that of the steel reinforced beam while the FRP reinforced beam developed unacceptably wide cracks. In the analytical part comprehensive analysis of the experimental data in both flexure and shear is performed. It is determined that the existing design expressions for ultimate flexural strength and service load deflection calculation cannot accurately predict the response of PCP reinforced beams. Accordingly, new expressions for calculation of deflection, crack width, tension stiffening, and ultimate capacity of the PCP reinforced beams are proposed. The predictions of the proposed methods of analysis agree very well with the corresponding experimental data. Based on the results of the current study, it is concluded that high strength concrete prisms prestressed with carbon fibre reinforced plastic bars can be used as reinforcement in concrete structures to avoid the problems of large deflections and wide cracks under service loads.

An inflatable belt system in the rear seat occupant environment: investigating feasibility and benefit in frontal impact sled tests with a 50th percentile male ATD

PubMed Central

Forman, Jason L.; Lopez-Valdes, Francisco J.; Dennis, Nate; Kent, Richard W.; Tanji, Hiromasa; Higuchi, Kazuo

2010-01-01

Frontal-impact airbag systems have the potential to provide a benefit to rear seat occupants by distributing restraining forces over the body in a manner not possible using belts alone. This study sought to investigate the effects of incorporating a belt-integrated airbag (“airbelt”) into a rear seat occupant restraint system. Frontal impact sled tests were performed with a Hybrid III 50th percentile male anthropomorphic test device (ATD) seated in the right-rear passenger position of a 2004 mid-sized sedan buck. Tests were performed at 48 km/h (20 g, 100 ms acceleration pulse) and 29 km/h (11 g, 100 ms). The restraints consisted of a 3-point belt system with a cylindrical airbag integrated into the upper portion of the shoulder belt. The airbag was tapered in shape, with a maximum diameter of 16 cm (at the shoulder) that decreased to 4 cm at the mid-chest. A 2.5 kN force-limiter was integrated into the shoulder-belt retractor, and a 2.3 kN pretensioner was present in the out-board anchor of the lap belt. Six ATD tests (three 48 km/h and three 29 km/h) were performed with the airbelt system. These were compared to previous frontal-impact, rear seat ATD tests with a standard (not-force-limited, not-pretensioned) 3-point belt system and a progressive force-limiting (peak 4.4 kN), pretensioning (FL+PT) 3-point belt system. In the 48 km/h tests, the airbelt resulted in significantly less (p<0.05, two-tailed Student’s t-test) posterior displacement of the sternum towards the spine (chest deflection) than both the standard and FL+PT belt systems (airbelt: average 13±1.1 mm standard deviation; standard belt: 33±2.3 mm; FL+PT belt: 23±2.6 mm). This was consistent with a significant reduction in the peak upper shoulder belt force (airbelt: 2.7±0.1 kN; standard belt: 8.7±0.3 kN; FL+PT belt: 4.4±0.1 kN), and was accompanied by a small increase in forward motion of the head (airbelt: 54±0.4 cm; standard belt: 45±1.3 cm; FL+PT belt: 47±1.1 cm) The airbelt system also significantly reduced the flexion moment in the lower neck (airbelt: 169±3.3 Nm; standard belt: 655±26 Nm; FL+PT belt: 308±19 Nm). Similar results were observed in the 29 km/h tests. These results suggest that this airbelt system may provide some benefit for adult rear seat occupants in frontal collisions, even in relatively low-speed impacts. Further study is needed to evaluate this type of restraint system for different size occupants (e.g., children), for out-of-position occupants, and with other occupant models (e.g., cadavers). PMID:21050596

Mechanics of biological polymer composites

NASA Astrophysics Data System (ADS)

Lomakin, Joseph

2009-12-01

Cartilage and cuticle are two natural materials capable of remarkable mechanical performance, especially considering the limitations on composition and processing conditions under which they are constructed. Their impressive properties are postulated to be a consequence of their complex multi-scale organization which has commonly been characterized by biochemical and microscopic methods. The objective of this dissertation is to overcome the limitations of such methods with mechanical analysis techniques generally reserved for the study of synthetic polymers. Methods for transient and dynamic mechanical analysis (DMA) of porcine TMJ disc sections and Tribolium castaneum and Tenebrio molitor elytral (modified forewing) cuticle were developed to characterize the mechanical performance of these biomaterials. The TMJ disc dynamic elastic modulus (E') was determined to be a strong function of disc orientation and pretension ranging from 700+/-240 kPa at (1g pretension) in the mediolateral direction to 73+/-8.5 MPa (150g preload) in the anteroposterior direction. Analogous mechanical testing was used to understand the relationship between composition and mechanical properties of beetle elytral cuticle at variable stages of maturation (tanning). Untanned elytra of both beetle species were ductile with a Young's modulus (E) of 44+/-8 MPa, but became brittle with an E of 2400+/-1100 MPa when fully tanned. Significantly, the E' of the TMJ disc and elytral cuticle exhibited a weak power law increase as a function of oscillation frequency. The exponent of the power law fit ( n) was determined to be a sensitive measure of molecular structure within these biomaterials. With increasing cuticular tanning, more so than with drying, the frequency dependence of cuticle E' diminished, suggesting cuticular cross-linking was an important component of tanning, as postulated by the quinone tanning hypothesis. The natural Black phenotype as well as TcADC iRNA suppressed Tribolium cuticle displayed a darker coloration and significantly increased n of 0.0470.004, suggesting both cuticles to be less cross-linked, a finding consistent with reduced beta-alanine metabolism. Suppression of the tanning enzyme laccase2 (TcLac2) resulted in a pale cuticle with an n of 0.043+/-0.005, implicating laccases in the formation of both pigments and cross-links during sclerotization. Cuticular cross-linking was increased and n decreased with decreased expression of structural proteins, CP10 and CP20. This work establishes n as an important novel parameter for confirming metabolic pathways within load bearing tissues and for understanding structure function relationships within biological polymer composites. Additionally, Tribolium castaneum elytral indentation modulus (800+/-200 MPa) was determined by nanoindentation and a 4nm regular hexagonal pattern on the dorsal side of elytra investigated via scanning, transmission and atomic microscopy. Based on studied biological materials, the combination of rigid macromolecules immersed in a ductile matrix was found to be significant in achieving exceptional mechanical performance. Inspired by this biological design principle, the synthesis, properties and structure of Poly(ethylene glycol) diacrylate/agarose semi-interpenetrating network hydrogels were explored. The resulting novel composite materials were 9x stiffer than agarose and 5x tougher than PEGDA alone and showed good biocompatibility, suggesting promise as a scaffold material for tissue engineering constructs for cartilage regeneration.

Behavior of Fiber Glass Bolts, Rock Bolts and Cable Bolts in Shear

NASA Astrophysics Data System (ADS)

Li, Xuwei; Aziz, Naj; Mirzaghorbanali, Ali; Nemcik, Jan

2016-07-01

This paper experimentally compares the shear behavior of fiber glass (FG) bolt, rock bolt (steel rebar bolt) and cable bolt for the bolt contribution to bolted concrete surface shear strength, and bolt failure mode. Two double shear apparatuses of different size were used for the study. The tensile strength, the shear strength and the deformation modulus of bolt control the shear behavior of a sheared bolted joint. Since the strength and deformation modulus of FG bolt, rock bolt and cable bolt obtained from uniaxial tensile tests are different, their shear behavior in reinforcing joints is accordingly different. Test results showed that the shear stiffness of FG bolted joints decreased gradually from the beginning to end, while the shear stiffness of joints reinforced by rock bolt and cable bolt decreased bi-linearly, which is clearly consistent with their tensile deformation modulus. The bolted joint shear stiffness was highly influenced by bolt pretension in the high stiffness stage for both rock bolt and cable bolt, but not in the low stiffness stage. The rock bolt contribution to joint shear strength standardised by the bolt tensile strength was the largest, followed by cable bolts, then FG bolts. Both the rock bolts and cable bolts tended to fail in tension, while FG bolts in shear due to their low shear strength and constant deformation modulus.

Investigating grounded conceptualization: motor system state-dependence facilitates familiarity judgments of novel tools.

PubMed

Matheson, Heath E; Familiar, Ariana M; Thompson-Schill, Sharon L

2018-03-02

Theories of embodied cognition propose that we recognize tools in part by reactivating sensorimotor representations of tool use in a process of simulation. If motor simulations play a causal role in tool recognition then performing a concurrent motor task should differentially modulate recognition of experienced vs. non-experienced tools. We sought to test the hypothesis that an incompatible concurrent motor task modulates conceptual processing of learned vs. non-learned objects by directly manipulating the embodied experience of participants. We trained one group to use a set of novel, 3-D printed tools under the pretense that they were preparing for an archeological expedition to Mars (manipulation group); we trained a second group to report declarative information about how the tools are stored (storage group). With this design, familiarity and visual attention to different object parts was similar for both groups, though their qualitative interactions differed. After learning, participants made familiarity judgments of auditorily presented tool names while performing a concurrent motor task or simply sitting at rest. We showed that familiarity judgments were facilitated by motor state-dependence; specifically, in the manipulation group, familiarity was facilitated by a concurrent motor task, whereas in the spatial group familiarity was facilitated while sitting at rest. These results are the first to directly show that manipulation experience differentially modulates conceptual processing of familiar vs. unfamiliar objects, suggesting that embodied representations contribute to recognizing tools.

The seasonal variations of allelopathic activity and allelopathic substances in Brachiaria brizantha.

PubMed

Kobayashi, Ai; Kato-Noguchi, Hisashi

2015-12-01

Controlling weeds through allelopathy is one strategy to reduce dependency on synthetic herbicides. The plant shoots of the grass Brachiaria brizantha incorporated into the field soil were found to inhibit the growth of several plant species. We investigated the variations of allelopathic activity and allelopathic substances in B. brizantha harvested in June, October and January. All extracts of B. brizantha obtained from June, October and January inhibited the root and shoot growth of cress, lettuce, Phleum pretense and Lolium multiflorum in a concentration dependent manner. However, the inhibitory activity of B. brizantha of June and October was greater than that of B. brizantha of January. Concentrations of three potent allelopathic active substances, (6R,9S)-3-oxo-α-ionol, (6R,9R)-3-oxo-α-ionol and 4-ketopinoresinol were also greater in B. brizantha of June and October than those in B. brizantha of January. The results suggest that the allelopathic activity and the levels of those allelopathic active substances are greater in B. brizantha of June and October than those in B. brizantha of January. It is possible that B. brizantha could be useful for a weed suppressive residue or soil additive materials in the variety of agricultural settings to develop sustainable agriculture options. The effectiveness of B. brizantha of June and October as a weed suppressive agent may be greater than that of January.

Decolonizing Bioethics in Africa

PubMed Central

Macaulay-Adeyelure, O.C.

2017-01-01

The global spread of bioethics from its North-American and European provenance to non-Western societies is currently raising some concerns. Part of the concern has to do with whether or not the exportation of bioethics in its full Western sense to developing non-Western states is an instance of ethical imperialism or bioethical neocolonialism. This paper attempts an exploration of this debate in the context of bioethics in sub-Saharan Africa. Rather than conceding that bioethics has a colonial agenda in Africa, this paper defends the position that the current bioethics trend in sub-Saharan Africa is an unintended imperialistic project. It argues that its colonizing character is not entirely a product of the Western programmed goals of training and institution building; rather, it is a structural consequence of many receptive African minds and institutions. Though bioethics in Africa is turning out as a colonizing project, one serious implication of such trend, if unchecked urgently, is that bioethics’ invaluable relevance to Africa is being incapacitated. This paper, therefore, attempts a decolonizing trajectory of bioethics in Africa. Contrary to the pretense of ‘African bioethics,’ which some African scholars are now defending, this paper through the logic of decolonization makes case for ‘bioethics in Africa’. In such logic, the principle of existential needs is prioritized over the principle of identity and authenticity that define African voice in bioethics. PMID:28344985

[Ethical relativism and the modern concept of tolerance].

PubMed

Laffitte, Jean

2008-01-01

History presents many examples of men and women who find themselves in a position of having to disobey civil law. The motives for such disobedience can only be founded on moral conscience, as influenced by other laws - immutable and recognized as true. The author studies the historical context of the appearance, during the Age of the Enlightenment, of a new concept: tolerance. Ceasing to represent the expression of the classical practical virtue of prudence, ideological tolerance achieves the rank of theoretical virtue. Such a pretension has a political in essence but also innumerable ethical consequences. An ideologically tolerant society is created. The author develops this paradoxical thesis according to which an ideologically tolerant society is not prepared to tolerate the idea that there might exist a truth for which to search. Today, we see a secularization of conscientious objection concerning two particular themes: military service and matters connected with the protection of human life. Examining the paradigmatic example of abortion, the author demonstrates how society is no longer capable of reflecting peacefully upon the question of the status of the embryo, for fear of questioning the legislative choice concerning its legalization. Thus, society no longer has the capability of confronting challenges connected to practices that are detrimental to the dignity of human life, the essential criteria that would allow it to face these matters having been declared outside the confines of future reflection.

[The ambivalence of love: from physiologic need to disease of the soul and of the body].

PubMed

Menghi, Martino

2005-01-01

In this writing we intend to examine the Epicurean notion of love as Lucretius presents it, both in the light of the perspective open by Jackie Pigeaud in an article on the erotic dream in antiquity and in a comparision with the Stoic view. We will notice the curious relationship there is between Lucretius' notion of simulacra and Stoic conception of phantasiai, but also the fundamental difference there is in their respective perception with what follows concerning the responsibility of the individual in his action. A passage of Seneca will show us that man can be morally corrupted to such an extent as to be able to shape up by himself negative phantasiai. But the portrait we will try to make of Epicurean and Stoic theory of love will give us the opportunity to see its integration into the medical thought of Roman imperial age. The attention of the most eminent physicians of I-II century to the pathological issues both for the soul and for the body of an excessive erotic life, indeed, not only depends on the heritage of Aristotelian acquisitions in the field of biology and psychology, but also presents some interesting links with Epicurean and Stoic theory of love, coherently with the pretension of some of these physicians to become the tutors of both physic and moral health of humanity.

Laterally bendable belt conveyor

DOEpatents

Peterson, William J.

1985-01-01

An endless, laterally flexible and bendable belt conveyor particularly adapted for coal mining applications in facilitating the transport of the extracted coal up- or downslope and around corners in a continuous manner is disclosed. The conveying means includes a flat rubber belt reinforced along the middle portion thereof along which the major portion of the belt tension is directed so as to cause rotation of the tubular shaped belt when trammed around lateral turns thus preventing excessive belt bulging distortion between adjacent belt supports which would inhibit belt transport. Pretension induced into the fabric reinforced flat rubber belt by conventional belt take-up means supports the load conveyed when the belt conveyor is making lateral turns. The carrying and return portions of the belt are supported and formed into a tubular shape by a plurality of shapers positioned along its length. Each shaper is supported from above by a monorail and includes clusters of idler rollers which support the belt. Additional cluster rollers in each shaper permit the belt supporting roller clusters to rotate in response to the belt's operating tension imposed upon the cluster rollers by induced lateral belt friction forces. The freely rotating roller clusters thus permit the belt to twist on lateral curves without damage to itself while precluding escape of the conveyed material by effectively enclosing it in the tube-shaped, inner belt transport length.

Dynamic High-Temperature Tensile Characterization of an Iridium Alloy with Kolsky Tension Bar Techniques

DOE PAGES

Song, Bo; Nelson, Kevin; Lipinski, Ronald; ...

2015-05-29

In this study, conventional Kolsky tension bar techniques were modified to characterize an iridium alloy in tension at elevated strain rates and temperatures. The specimen was heated to elevated temperatures with an induction coil heater before dynamic loading; whereas, a cooling system was applied to keep the bars at room temperature during heating. A preload system was developed to generate a small pretension load in the bar system during heating in order to compensate for the effect of thermal expansion generated in the high-temperature tensile specimen. A laser system was applied to directly measure the displacements at both ends ofmore » the tensile specimen in order to calculate the strain in the specimen. A pair of high-sensitivity semiconductor strain gages was used to measure the weak transmitted force due to the low flow stress in the thin specimen at elevated temperatures. The dynamic high-temperature tensile stress–strain curves of a DOP-26 iridium alloy were experimentally obtained at two different strain rates (~1000 and 3000 s -1) and temperatures (~750 and 1030°C). The effects of strain rate and temperature on the tensile stress–strain response of the iridium alloy were determined. Finally, the iridium alloy exhibited high ductility in stress–strain response that strongly depended on strain-rate and temperature.« less

Behaviour of Frictional Joints in Steel Arch Yielding Supports

NASA Astrophysics Data System (ADS)

Horyl, Petr; Šňupárek, Richard; Maršálek, Pavel

2014-10-01

The loading capacity and ability of steel arch supports to accept deformations from the surrounding rock mass is influenced significantly by the function of the connections and in particular, the tightening of the bolts. This contribution deals with computer modelling of the yielding bolt connections for different torques to determine the load-bearing capacity of the connections. Another parameter that affects the loading capacity significantly is the value of the friction coefficient of the contacts between the elements of the joints. The authors investigated both the behaviour and conditions of the individual parts for three values of tightening moment and the relation between the value of screw tightening and load-bearing capacity of the connections for different friction coefficients. ANSYS software and the finite element method were used for the computer modelling. The solution is nonlinear because of the bi-linear material properties of steel and the large deformations. The geometry of the computer model was created from designs of all four parts of the structure. The calculation also defines the weakest part of the joint's structure based on stress analysis. The load was divided into two loading steps: the pre-tensioning of connecting bolts and the deformation loading corresponding to 50-mm slip of one support. The full Newton-Raphson method was chosen for the solution. The calculations were carried out on a computer at the Supercomputing Centre VSB-Technical University of Ostrava.

On Earthquake Prediction in Japan

PubMed Central

UYEDA, Seiya

2013-01-01

Japan’s National Project for Earthquake Prediction has been conducted since 1965 without success. An earthquake prediction should be a short-term prediction based on observable physical phenomena or precursors. The main reason of no success is the failure to capture precursors. Most of the financial resources and manpower of the National Project have been devoted to strengthening the seismographs networks, which are not generally effective for detecting precursors since many of precursors are non-seismic. The precursor research has never been supported appropriately because the project has always been run by a group of seismologists who, in the present author’s view, are mainly interested in securing funds for seismology — on pretense of prediction. After the 1995 Kobe disaster, the project decided to give up short-term prediction and this decision has been further fortified by the 2011 M9 Tohoku Mega-quake. On top of the National Project, there are other government projects, not formally but vaguely related to earthquake prediction, that consume many orders of magnitude more funds. They are also un-interested in short-term prediction. Financially, they are giants and the National Project is a dwarf. Thus, in Japan now, there is practically no support for short-term prediction research. Recently, however, substantial progress has been made in real short-term prediction by scientists of diverse disciplines. Some promising signs are also arising even from cooperation with private sectors. PMID:24213204

Play in two societies: pervasiveness of process, specificity of structure.

PubMed

Bornstein, M H; Haynes, O M; Pascual, L; Painter, K M; Galperín, C

1999-01-01

The present study compared Argentine (N = 39) and U.S. (N = 43) children and their mothers on exploratory, symbolic, and social play and interaction when children were 20 months of age. Patterns of cultural similarity and difference emerged. In both cultures, boys engaged in more exploratory play than girls, and girls engaged in more symbolic play than boys; mothers of boys engaged in more exploratory play than mothers of girls, and mothers of girls engaged in more symbolic play than mothers of boys. Moreover, in both cultures, individual variation in children's exploratory and symbolic play was specifically associated with individual variation in mothers' exploratory and symbolic play, respectively. Between cultures, U.S. children and their mothers engaged in more exploratory play, whereas Argentine children and their mothers engaged in more symbolic play. Moreover, Argentine mothers exceeded U.S. mothers in social play and verbal praise of their children. During an early period of mental and social growth, general developmental processes in play may be pervasive, but dyadic and cultural structures are apparently specific. Overall, Argentine and U.S. dyads utilized different modes of exploration, representation, and interaction--emphasizing "other-directed" acts of pretense versus "functional" and "combinatorial" exploration, for example--and these individual and dyadic allocentric versus idiocentric stresses accord with larger cultural concerns of collectivism versus individualism in the two societies.

The epistemology of climate models and some of its implications for climate science and the philosophy of science

NASA Astrophysics Data System (ADS)

Katzav, Joel

2014-05-01

I bring out the limitations of four important views of what the target of useful climate model assessment is. Three of these views are drawn from philosophy. They include the views of Elisabeth Lloyd and Wendy Parker, and an application of Bayesian confirmation theory. The fourth view I criticise is based on the actual practice of climate model assessment. In bringing out the limitations of these four views, I argue that an approach to climate model assessment that neither demands too much of such assessment nor threatens to be unreliable will, in typical cases, have to aim at something other than the confirmation of claims about how the climate system actually is. This means, I suggest, that the Intergovernmental Panel on Climate Change's (IPCC's) focus on establishing confidence in climate model explanations and predictions is misguided. So too, it means that standard epistemologies of science with pretensions to generality, e.g., Bayesian epistemologies, fail to illuminate the assessment of climate models. I go on to outline a view that neither demands too much nor threatens to be unreliable, a view according to which useful climate model assessment typically aims to show that certain climatic scenarios are real possibilities and, when the scenarios are determined to be real possibilities, partially to determine how remote they are.

Parametric Studies of Square Solar Sails Using Finite Element Analysis

NASA Technical Reports Server (NTRS)

Sleight, David W.; Muheim, Danniella M.

2004-01-01

Parametric studies are performed on two generic square solar sail designs to identify parameters of interest. The studies are performed on systems-level models of full-scale solar sails, and include geometric nonlinearity and inertia relief, and use a Newton-Raphson scheme to apply sail pre-tensioning and solar pressure. Computational strategies and difficulties encountered during the analyses are also addressed. The purpose of this paper is not to compare the benefits of one sail design over the other. Instead, the results of the parametric studies may be used to identify general response trends, and areas of potential nonlinear structural interactions for future studies. The effects of sail size, sail membrane pre-stress, sail membrane thickness, and boom stiffness on the sail membrane and boom deformations, boom loads, and vibration frequencies are studied. Over the range of parameters studied, the maximum sail deflection and boom deformations are a nonlinear function of the sail properties. In general, the vibration frequencies and modes are closely spaced. For some vibration mode shapes, local deformation patterns that dominate the response are identified. These localized patterns are attributed to the presence of negative stresses in the sail membrane that are artifacts of the assumption of ignoring the effects of wrinkling in the modeling process, and are not believed to be physically meaningful. Over the range of parameters studied, several regions of potential nonlinear modal interaction are identified.

Perennial peanut (Arachis glabrata Benth.) contains polyphenol oxidase (PPO) and PPO substrates that can reduce post-harvest proteolysis.

PubMed

Sullivan, Michael L; Foster, Jamie L

2013-08-15

Studies of perennial peanut (Arachis glabrata Benth.) suggest its hay and haylage have greater levels of rumen undegraded protein (RUP) than other legume forages such as alfalfa (Medicago sativa L.). Greater RUP can result in more efficient nitrogen utilization by ruminant animals with positive economic and environmental effects. We sought to determine whether, like red clover (Trifolium pretense L.), perennial peanut contains polyphenol oxidase (PPO) and PPO substrates that might be responsible for increased RUP. Perennial peanut extracts contain immunologically detectible PPO protein and high levels of PPO activity (>100 nkatal mg(-1) protein). Addition of caffeic acid (PPO substrate) to perennial peanut extracts depleted of endogenous substrates reduced proteolysis by 90%. Addition of phenolics prepared from perennial peanut leaves to extracts of either transgenic PPO-expressing or control (non-expressing) alfalfa showed peanut phenolics could reduce proteolysis >70% in a PPO-dependent manner. Two abundant likely PPO substrates are present in perennial peanut leaves including caftaric acid. Perennial peanut contains PPO and PPO substrates that together are capable of inhibiting post-harvest proteolysis, suggesting a possible mechanism for increased RUP in this forage. Research related to optimizing the PPO system in other forage crops will likely be applicable to perennial peanut. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Inverse measurement of wall pressure field in flexible-wall wind tunnels using global wall deformation data

NASA Astrophysics Data System (ADS)

Brown, Kenneth; Brown, Julian; Patil, Mayuresh; Devenport, William

2018-02-01

The Kevlar-wall anechoic wind tunnel offers great value to the aeroacoustics research community, affording the capability to make simultaneous aeroacoustic and aerodynamic measurements. While the aeroacoustic potential of the Kevlar-wall test section is already being leveraged, the aerodynamic capability of these test sections is still to be fully realized. The flexibility of the Kevlar walls suggests the possibility that the internal test section flow may be characterized by precisely measuring small deflections of the flexible walls. Treating the Kevlar fabric walls as tensioned membranes with known pre-tension and material properties, an inverse stress problem arises where the pressure distribution over the wall is sought as a function of the measured wall deflection. Experimental wall deformations produced by the wind loading of an airfoil model are measured using digital image correlation and subsequently projected onto polynomial basis functions which have been formulated to mitigate the impact of measurement noise based on a finite-element study. Inserting analytic derivatives of the basis functions into the equilibrium relations for a membrane, full-field pressure distributions across the Kevlar walls are computed. These inversely calculated pressures, after being validated against an independent measurement technique, can then be integrated along the length of the test section to give the sectional lift of the airfoil. Notably, these first-time results are achieved with a non-contact technique and in an anechoic environment.

Superoxide Anion Radical Scavenging Activities of Herbs and Pastures in Northern Japan Determined Using Electron Spin Resonance Spectrometry

PubMed Central

Al-Mamun, Mohammad; Yamaki, Koji; Masumizu, Toshiki; Nakai, Yumi; Saito, Katsumi; Sano, Hiroaki; Tamura, Yoshifumi

2007-01-01

Free radicals are not only destructive to the living cells but also reduce the quality of animal products through oxidation. As a result the superoxide anion radical (O2・-), one of the most destructive reactive oxygen species, is a matter of concern for the animal scientists as well as feed manufacturers to ensure the quality of product to reach consumers demand. The superoxide anion radical scavenging activities (SOSA) of water and MeOH extracts of 2 herbs and 9 pasture samples collected from lowland and highland swards were determined against a 5,5-dimethyl-1-pyroline-N-oxide-O2・-spin adduct based on a hypoxanthine-xanthine oxidase reaction using electron spin resonance spectrometry. Both the water and MeOH extracted SOSA differed among the herbs and pastures. Species and altitudinal variations were observed between extraction methods. The herbs were higher in both water and MeOH extracted SOSA than the pastures except for water extracts of one pasture, white clover (Trifolium repens L.). Among the pastures, quackgrass (Agrophyron repens L.) showed higher SOSA in both the MeOH and water extracts, and timothy (Phleum pretense L.) showed higher MeOH extracted SOSA. It is apparent that the kind and amount of antioxidants differ among herbs and pastures. Animal health and quality of animal products could be improved by adequate selection and combining of herbs and pastures having higher SOSA. PMID:17713599

Experimental Investigations on Subsequent Yield Surface of Pure Copper by Single-Sample and Multi-Sample Methods under Various Pre-Deformation.

PubMed

Liu, Gui-Long; Huang, Shi-Hong; Shi, Che-Si; Zeng, Bin; Zhang, Ke-Shi; Zhong, Xian-Ci

2018-02-10

Using copper thin-walled tubular specimens, the subsequent yield surfaces under pre-tension, pre-torsion and pre-combined tension-torsion are measured, where the single-sample and multi-sample methods are applied respectively to determine the yield stresses at specified offset strain. The rule and characteristics of the evolution of the subsequent yield surface are investigated. Under the conditions of different pre-strains, the influence of test point number, test sequence and specified offset strain on the measurement of subsequent yield surface and the concave phenomenon for measured yield surface are studied. Moreover, the feasibility and validity of the two methods are compared. The main conclusions are drawn as follows: (1) For the single or multi-sample method, the measured subsequent yield surfaces are remarkably different from cylindrical yield surfaces proposed by the classical plasticity theory; (2) there are apparent differences between the test results from the two kinds of methods: the multi-sample method is not influenced by the number of test points, test order and the cumulative effect of residual plastic strain resulting from the other test point, while those are very influential in the single-sample method; and (3) the measured subsequent yield surface may appear concave, which can be transformed to convex for single-sample method by changing the test sequence. However, for the multiple-sample method, the concave phenomenon will disappear when a larger offset strain is specified.

Derivation of Heliophysical Scientific Data from Amateur Observations of Solar Eclipses

NASA Astrophysics Data System (ADS)

Stoev, A. D.; Stoeva, P. V.

2006-03-01

The basic scientific aims and observational experiments included in the complex observational program - Total Solar Eclipse '99 - are described in the work. Results from teaching and training students of total solar eclipse (TSE) observation in the Public Astronomical Observatory (PAO) in Stara Zagora and their selection for participation in different observational teams are also discussed. During the final stage, a special system of methods for investigation of the level of pretensions (the level of ambition as to what he/she feels capable of achieving in the context of problem solving/observation) of the students is applied. Results obtained from the observational experiments are interpreted mainly in the following themes: Investigation of the structure of the white-light solar corona and evolution of separate coronal elements during the total phase of the eclipse; Photometry of the white-light solar corona and specific emission lines; Meteorological, actinometrical and optical atmospheric investigations; Astrometry of the Moon during the phase evolution of the eclipse; Biological and behavioral reactions of highly organized colonies (ants and bats) during the eclipse. It is also shown that data processing, observational results and their interpretation, presentation and publishing in specialized and amateur editions is a peak in the independent creative activity of students and amateur astronomers. This enables students from the Astronomy schools at Public Astronomical Observatories and Planetariums (PAOP) to develop creative skills, emotional - volitional personal qualities, orientation towards scientific work, observations and experiments, and build an effective scientific style of thinking.

The Anatomy of A.L.I.C.E.

NASA Astrophysics Data System (ADS)

Wallace, Richard S.

This paper is a technical presentation of Artificial Linguistic Internet Computer Entity (A.L.I.C.E.) and Artificial Intelligence Markup Language (AIML), set in context by historical and philosophical ruminations on human consciousness. A.L.I.C.E., the first AIML-based personality program, won the Loebner Prize as "the most human computer" at the annual Turing Test contests in 2000, 2001, and 2004. The program, and the organization that develops it, is a product of the world of free software. More than 500 volunteers from around the world have contributed to her development. This paper describes the history of A.L.I.C.E. and AIML-free software since 1995, noting that the theme and strategy of deception and pretense upon which AIML is based can be traced through the history of Artificial Intelligence research. This paper goes on to show how to use AIML to create robot personalities like A.L.I.C.E. that pretend to be intelligent and selfaware. The paper winds up with a survey of some of the philosophical literature on the question of consciousness. We consider Searle's Chinese Room, and the view that natural language understanding by a computer is impossible. We note that the proposition "consciousness is an illusion" may be undermined by the paradoxes it apparently implies. We conclude that A.L.I.C.E. does pass the Turing Test, at least, to paraphrase Abraham Lincoln, for some of the people some of the time.

Characterisation of phenolics in Flor-Essence--a compound herbal product and its contributing herbs.

PubMed

Saleem, Ammar; Walshe-Roussel, Brendan; Harris, Cory; Asim, Muhammad; Tamayo, Carmen; Sit, Summer; Arnason, John Thor

2009-01-01

Commercially available herbal mixture FE, a proprietary natural health product manufactured by Flora Manufacturing and Distributing Ltd (Flora), is a unique North American traditional herbal product. FE is a chemically complex mixture of eight herbs and has not been subjected to phytochemical analysis. To develop analytical methods to undertake detailed phytochemical analyses of FE, and its eight contributing herbs, including burdock (Arctium lappa L.), sheep sorrel (Rumex acetosella L.), Turkish rhubarb (Rheum palmatum L.), slippery elm Muhl. (Ulmus rubra), watercress (Nasturtium officinale R. Br.), red clover (Trifolium pratense L.), blessed thistle (Cnicus benedictus L.) and kelp (Laminaria digitata Lmx.). The identification was undertaken by a combination of reversed phase high performance liquid chromatography-diode array detection-atmospheric pressure chemical ionisation-mass selective detection (RP-HPLC-DAD-APCI-MSD) analysis and phenolics metabolomic library matching. New separation methods facilitated the identification of 43 markers in the individual herbs which constitute FE. Sixteen markers could be identified in FE originating from four contributing herbs including four caffeoyl quinic acids, three dicaffeoyl quinic acids and two caffeic acid derivatives from A. lappa, luteolin-7-O-glucoside, luteolin, five apigenin glycosides and apigenin from R. acetocella and N. officinale and sissostrin from T. pretense. A validated method for quantitative determination of three markers is reported with good intraday, interday and interoperator repeatability using a reliable alcohol based extraction technique. FE and its contributing herbs predominantly contain phenolics. This methodology can be applied to further develop full-scale validation of this product.

Z-2 Threaded Insert Design and Testing

NASA Technical Reports Server (NTRS)

Ross, Amy; Rhodes, Richard; Jones, Robert J.; Graziosi, David; Ferl, Jinny; Sweeny, Mitch; Scarborough, Stephen

2016-01-01

NASA's Z-2 prototype space suit contains several components fabricated from an advanced hybrid composite laminate consisting of IM10 carbon fiber and fiber glass. One requirement was to have removable, replaceable helicoil inserts to which other suit components would be fastened. An approach utilizing bonded in inserts with helicoils inside of them was implemented. During initial assembly, cracking sounds were heard followed by the lifting of one of the blind inserts out of its hole when the screws were torqued. A failure investigation was initiated to understand the mechanism of the failure. Ultimately, it was determined that the pre-tension caused by torqueing the fasteners is a much larger force than induced from the pressure loads of the suit which was not considered in the insert design. Bolt tension is determined by dividing the torque on the screw by a k value multiplied by the thread diameter of the bolt. The k value is a factor that accounts for friction in the system. A common value used for k for a non-lubricated screw is 0.2. The k value can go down by as much as 0.1 if the screw is lubricated which means for the same torque, a much larger tension could be placed on the bolt and insert. This paper summarizes the failure investigation that was performed to identify the root cause of the suit failure and details how the insert design was modified to resist a higher pull out tension.

Frictional contact behaviour of the tyre: the effect of tread slip on the in-plane structural deformation and stress field development

NASA Astrophysics Data System (ADS)

Tsotras, Achillefs; Mavros, George

2010-08-01

The analysis of the in-plane deformation of the tyre in relation to the frictional contact between the road and the tread is a crucial first step in the understanding of its contribution to the longitudinal dynamics of a vehicle. In this work, the physical mechanism of the generation of the two-dimensional contact pressure distribution for a non-rolling tyre is studied. Towards this aim, a physical tyre model is constructed, consisting of an analytical ring under pretension, a non-linear sidewall foundation, and a discretised foundation of viscoelastic elements representing the tread. Tread behaviour is examined first, with focus on the development of shear micro-slip. The tread simulation is enhanced with the combination of radial and tangential tread elements and the benefits of such an approach are identified. Subsequently, the contact of the complete model is examined by implementing an algorithm for transient simulations in the time domain. The effects of the imposed vertical load and sidewall non-linearity on the contact stress and strain fields are identified. The modelling approach is validated by comparison with published experimental results. The physical mechanism that couples the torsional and horizontal/vertical deformations of the carcass with the frictional forces at the tread is identified and discussed in detail. The proposed modelling approach is found appropriate for the description of the development of the two-dimensional contact pressure field as a function of the frictional potential of the contact.

Style and non-style in anatomical illustration: From Renaissance Humanism to Henry Gray.

PubMed

Kemp, Martin

2010-02-01

Style is a familiar category for the analysis of art. It is less so in the history of anatomical illustration. The great Renaissance and Baroque picture books of anatomy illustrated with stylish woodcuts and engravings, such as those by Charles Estienne, Andreas Vesalius and Govard Bidloo, showed figures in dramatic action in keeping with philosophical and theological ideas about human nature. Parallels can be found in paintings of the period, such as those by Titian, Michelangelo and Hans Baldung Grien. The anatomists also claimed to portray the body in an objective manner, and showed themselves as heroes of the discovery of human knowledge. Rembrandt's painting of Dr Nicholas Tulp is the best-known image of the anatomist as hero. The British empirical tradition in the 18th century saw William Cheselden and William Hunter working with techniques of representation that were intended to guarantee detailed realism. The ambition to portray forms life-size led to massive volumes, such as those by Antonio Mascagni. John Bell, the Scottish anatomist, criticized the size and pretensions of the earlier books and argued for a plain style adapted to the needs of teaching and surgery. Henry Gray's famous Anatomy of 1858, illustrated by Henry Vandyke Carter, aspired to a simple descriptive mode of functional representation that avoided stylishness, resulting in a style of its own. Successive editions of Gray progressively saw the replacement of Gray's method and of all his illustrations. The 150th anniversary edition, edited by Susan Standring, radically re-thinks the role of Gray's book within the teaching of medicine.

Control of CFRP strengthening applied to civil structures by IR thermography

NASA Astrophysics Data System (ADS)

Grinzato, E.; Trentin, R.; Bison, P. G.; Marinetti, S.

2007-04-01

NdT methods are highly promoted by an increasing demand of checking the effectiveness of strengthening and repair intervention on structural components, both in buildings and bridges. IR thermography exhibits excellent performances, particularly when innovative materials as CFRP (Carbon Fiber Reinforced Polymer) are used. Non destructive control by the use of thermographic analysis is used to detect adhesion defects or imperfections, which can lead the component to become brittle and collapsing unexpectedly. This paper shows as the geometrical evaluation of delaminated areas is carried out. Laboratory tests both on reduced or full scale are illustrated in order to set up and validate the proposed procedure. An experimental study on samples bonded with FRP and containing defects appropriately applied at the interface, will be presented. A series of beams (10 m long) have been tested under bending loads and strengthened conditions, by placing a pre-impregnated thin carbon (CFRP) laminate at the intrados. Different reinforcement configurations have been adopted in the beams (ordinary steel reinforcement and with addition of pre-stressed strands), using mechanical devices for the anchorage of the supplementary pre-tension of the strips. At local level, the simulation of possible lack of bonding during loading or intrinsic defects and imperfections has been contextually analysed on specifically dimensioned specimens. Different algorithms have been applied at the evaluation stage in order to estimate the defect size and location. Particularly, the extension of the delamination is estimate with a simple and robust algorithm. In facts, standards set the limit for acceptable defects, both in terms of number and size.

Mechanistic basis of manual therapy in myofascial injuries. Sonoelastographic evolution control.

PubMed

Martínez Rodríguez, Raúl; Galán del Río, Fernando

2013-04-01

The term myofascia is referred to the skeleton of muscle fibres organized as an interconnected 3D network that surrounds and connects the musculoskeletal system. Extracellular matrix muscle is relevant in tissue structural support and transmission of mechanical signals between fibres and tendons. Acute and chronic musculoskeletal injuries (muscle strain) are one of the major problems faced by those who practice any type of sport, regardless of whether they are professionals or amateurs. Therapeutic boarding is of uncertain value in most cases because there are many contributing factors such as type, severity, functional implication of the damaged tissue, progression or risk of relapse. Different studies suggest that the musculoskeletal cell matrix is essential for the development, maintenance and regeneration of skeletal muscle. In this article, we highlight the action of "non-contractile" structures, in particular the myofascial system or muscle fascia, which can be responsible for the pathophysiology and healing process of muscular injuries. Manual therapy plays a predominant role in the treatment of these types of injuries and is key in the process of obtaining a scar capable of transmitting mechanical information. The scientific basis of this process is described in this article. Through real-time sonoelastography we have accurate information regarding the current stage of the repair process and, thus, guide our treatment at all times. Some new concepts are introduced, including local elasticity, the relationship between fascial pretension and the different stages of the physiological myofascia repair process, scar modelling technique, and sonoelastographic evolution control. Copyright © 2012 Elsevier Ltd. All rights reserved.

A magnetically actuated cellular strain assessment tool for quantitative analysis of strain induced cellular reorientation and actin alignment

NASA Astrophysics Data System (ADS)

Khademolhosseini, F.; Liu, C.-C.; Lim, C. J.; Chiao, M.

2016-08-01

Commercially available cell strain tools, such as pneumatically actuated elastomer substrates, require special culture plates, pumps, and incubator setups. In this work, we present a magnetically actuated cellular strain assessment tool (MACSAT) that can be implemented using off-the-shelf components and conventional incubators. We determine the strain field on the MACSAT elastomer substrate using numerical models and experimental measurements and show that a specific region of the elastomer substrate undergoes a quasi-uniaxial 2D stretch, and that cells confined to this region of the MACSAT elastomer substrate undergo tensile, compressive, or zero axial strain depending on their angle of orientation. Using the MACSAT to apply cyclic strain on endothelial cells, we demonstrate that actin filaments within the cells reorient away from the stretching direction, towards the directions of minimum axial strain. We show that the final actin orientation angles in strained cells are spread over a region of compressive axial strain, confirming previous findings on the existence of a varied pre-tension in the actin filaments of the cytoskeleton. We also demonstrate that strained cells exhibit distinctly different values of actin alignment coherency compared to unstrained cells and therefore propose that this parameter, i.e., the coherency of actin alignment, can be used as a new readout to determine the occurrence/extent of actin alignment in cell strain experiments. The tools and methods demonstrated in this study are simple and accessible and can be easily replicated by other researchers to study the strain response of other adherent cells.

The adequacy of current import and export controls on sealed radioactive sources.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Longley, Susan W.; Cochran, John Russell; Price, Laura L.

2003-10-01

Millions of sealed radioactive sources (SRSs) are being used for a wide variety of beneficial purposes throughout the world. Security experts are now concerned that these beneficial SRSs could be used in a radiological dispersion device to terrorize and disrupt society. The greatest safety and security threat is from those highly radioactive Category 1 and 2 SRSs. Without adequate controls, it may be relatively easy to legally purchase a Category 1 or 2 SRS on the international market under false pretenses. Additionally, during transfer, SRSs are particularly susceptible to theft since the sources are in a shielded and mobile configuration,more » transportation routes are predictable, and shipments may not be adequately guarded. To determine if government controls on SRS are adequate, this study was commissioned to review the current SRS import and export controls of six countries. Canada, the Russian Federation, and South Africa were selected as the exporting countries, and Egypt, the Philippines, and the United States were selected as importing countries. A detailed review of the controls in each country is presented. The authors found that Canada and Russia are major exporters, and are exporting highly radioactive SRSs without first determining if the recipient is authorized by the receiving country to own and use the SRSs. Available evidence was used to estimate that on average there are tens to possibly hundreds of intercountry transfers of highly radioactive SRSs each day. Based on these and other findings, this reports recommends stronger controls on the export and import of highly radioactive SRSs.« less

Comment on Geoengineering with seagrasses: is credit due where credit is given?

NASA Astrophysics Data System (ADS)

Oreska, Matthew P. J.; McGlathery, Karen J.; Emmer, Igino M.; Needelman, Brian A.; Emmett-Mattox, Stephen; Crooks, Stephen; Megonigal, J. Patrick; Myers, Doug

2018-03-01

In their recent review, ‘Geoengineering with seagrasses: is credit due where credit is given?,’ Johannessen and Macdonald (2016) invoke the prospect of carbon offset-credit over-allocation by the Verified Carbon Standard as a pretense for their concerns about published seagrass carbon burial rate and global stock estimates. Johannessen and Macdonald (2016) suggest that projects seeking offset-credits under the Verified Carbon Standard methodology VM0033: Methodology for Tidal Wetland and Seagrass Restoration will overestimate long-term (100 yr) sediment organic carbon (SOC) storage because issues affecting carbon burial rates bias storage estimates. These issues warrant serious consideration by the seagrass research community; however, VM0033 does not refer to seagrass SOC ‘burial rates’ or ‘storage.’ Projects seeking credits under VM0033 must document greenhouse gas emission reductions over time, relative to a baseline scenario, in order to receive credits. Projects must also monitor changes in carbon pools, including SOC, to confirm that observed benefits are maintained over time. However, VM0033 allows projects to conservatively underestimate project benefits by citing default values for specific accounting parameters, including CO2 emissions reductions. We therefore acknowledge that carbon crediting methodologies such as VM0033 are sensitive to the quality of the seagrass literature, particularly when permitted default factors are based in part on seagrass burial rates. Literature-derived values should be evaluated based on the concerns raised by Johannessen and Macdonald (2016), but these issues should not lead to credit over-allocation in practice, provided VM0033 is rigorously followed. These issues may, however, affect the feasibility of particular seagrass offset projects.

Style and non-style in anatomical illustration: From Renaissance Humanism to Henry Gray

PubMed Central

Kemp, Martin

2010-01-01

Style is a familiar category for the analysis of art. It is less so in the history of anatomical illustration. The great Renaissance and Baroque picture books of anatomy illustrated with stylish woodcuts and engravings, such as those by Charles Estienne, Andreas Vesalius and Govard Bidloo, showed figures in dramatic action in keeping with philosophical and theological ideas about human nature. Parallels can be found in paintings of the period, such as those by Titian, Michelangelo and Hans Baldung Grien. The anatomists also claimed to portray the body in an objective manner, and showed themselves as heroes of the discovery of human knowledge. Rembrandt’s painting of Dr Nicholas Tulp is the best-known image of the anatomist as hero. The British empirical tradition in the 18th century saw William Cheselden and William Hunter working with techniques of representation that were intended to guarantee detailed realism. The ambition to portray forms life-size led to massive volumes, such as those by Antonio Mascagni. John Bell, the Scottish anatomist, criticized the size and pretensions of the earlier books and argued for a plain style adapted to the needs of teaching and surgery. Henry Gray’s famous Anatomy of 1858, illustrated by Henry Vandyke Carter, aspired to a simple descriptive mode of functional representation that avoided stylishness, resulting in a style of its own. Successive editions of Gray progressively saw the replacement of Gray’s method and of all his illustrations. The 150th anniversary edition, edited by Susan Standring, radically re-thinks the role of Gray’s book within the teaching of medicine. PMID:20447244

Evaluation of total knee mechanics using a crouching simulator with a synthetic knee substitute.

PubMed

Lowry, Michael; Rosenbaum, Heather; Walker, Peter S

2016-05-01

Mechanical evaluation of total knees is frequently required for aspects such as wear, strength, kinematics, contact areas, and force transmission. In order to carry out such tests, we developed a crouching simulator, based on the Oxford-type machine, with novel features including a synthetic knee including ligaments. The instrumentation and data processing methods enabled the determination of contact area locations and interface forces and moments, for a full flexion-extension cycle. To demonstrate the use of the simulator, we carried out a comparison of two different total knee designs, cruciate retaining and substituting. The first part of the study describes the simulator design and the methodology for testing the knees without requiring cadaveric knee specimens. The degrees of freedom of the anatomic hip and ankle joints were reproduced. Flexion-extension was obtained by changing quadriceps length, while variable hamstring forces were applied using springs. The knee joint was represented by three-dimensional printed blocks on to which the total knee components were fixed. Pretensioned elastomeric bands of realistic stiffnesses passed through holes in the block at anatomical locations to represent ligaments. Motion capture of the knees during flexion, together with laser scanning and computer modeling, was used to reconstruct contact areas on the bearing surfaces. A method was also developed for measuring tibial component interface forces and moments as a comparative assessment of fixation. The method involved interposing Tekscan pads at locations on the interface. Overall, the crouching machine and the methodology could be used for many different mechanical measurements of total knee designs, adapted especially for comparative or parametric studies. © IMechE 2016.

Effect of a novel sterilization method on biomechanical properties of soft tissue allografts.

PubMed

Baldini, T; Caperton, K; Hawkins, M; McCarty, E

2016-12-01

Evaluate allograft tissue commonly used in soft tissue reconstruction to determine whether stiffness and strength were significantly altered after grafts were treated with different sterilization methods. Unprocessed, irradiated, and grafts treated with supercritical CO 2 were compared. Thirty-eight anterior or posterior tibialis tendons were obtained from a tissue bank (Allograft Innovations, Gainesville, FL). Group I was unprocessed, group II was sterilized with gamma irradiation (20-28 kGy), and group III was sterilized with supercritical CO 2 . The grafts were pretensioned to 89 N for 300 s. Specimens were then loaded from 50 to 300 N at 0.5 Hz for 250 cycles before being loaded to failure at 50 mm/min. Dependent variables were compared between sterilization groups with one-way ANOVA (P < 0.05) and equivalence trial. There was no significant difference in load to failure or failure stress among groups I, II, and III. Group III resulted in 27-36 % lower stiffness than group I and II. This difference was significant at 1, 10, 50, 100, and 250 cycles. There was no significant difference in stiffness between group I and group II. The two sterilization methods tested in this study do not affect allograft strength. The supercritical CO 2 sterilization method resulted in significantly lower stiffness than unprocessed and irradiated allografts. However, the stiffness and strength of all groups tested were greater than that of published values of the native intact anterior cruciate ligament (ACL). This study provides previously unpublished mechanical test data on a new sterilization technique that will assist surgeons to decide which allograft to use in ACL reconstruction surgery. III.

The relationship between quadriceps muscle force, knee flexion, and anterior cruciate ligament strain in an in vitro simulated jump landing.

PubMed

Withrow, Thomas J; Huston, Laura J; Wojtys, Edward M; Ashton-Miller, James A

2006-02-01

An instrumented cadaveric knee construct was used to quantify the association between impact force, quadriceps force, knee flexion angle, and anterior cruciate ligament relative strain in simulated unipedal jump landings. Anterior cruciate ligament strain will correlate with impact force, quadriceps force, and knee flexion angle. Descriptive laboratory study. Eleven cadaveric knees (age, 70.8 [19.3] years; 5 male; 6 female) were mounted in a custom fixture with the tibia and femur secured to a triaxial load cell. Quadriceps, hamstring, and gastrocnemius muscle forces were simulated using pretensioned steel cables (stiffness, 7 kN/cm), and the quadriceps tendon force was measured using a load cell. Mean strain on the anteromedial bundle of the anterior cruciate ligament was measured using a DVRT. With the knee in 25 degrees of flexion, the construct was vertically loaded by an impact force initially directed 4 cm posterior to the knee joint center. Tibiofemoral kinematics was measured using a 3D optoelectronic tracking system. The increase in anterior cruciate ligament relative strain was proportional to the increase in quadriceps force (r(2) = 0.74; P < .00001) and knee flexion angle (r(2) = 0.88; P < .00001) but was not correlated with the impact force (r(2) = 0.009; P = .08). The increase in knee flexion and quadriceps force during this simulated 1-footed landing strongly influenced the relative strain on the anteromedial bundle of the anterior cruciate ligament. These results suggest that even in the presence of knee flexor muscle forces, the increase in quadriceps force required to prevent the knee from flexing during landing can place the anterior cruciate ligament at risk for large strains.

Elastic energy within the human plantar aponeurosis contributes to arch shortening during the push-off phase of running.

PubMed

Wager, Justin C; Challis, John H

2016-03-21

During locomotion, the lower limb tendons undergo stretch and recoil, functioning like springs that recycle energy with each step. Cadaveric testing has demonstrated that the arch of the foot operates in this capacity during simple loading, yet it remains unclear whether this function exists during locomotion. In this study, one of the arch׳s passive elastic tissues (the plantar aponeurosis; PA) was investigated to glean insights about it and the entire arch of the foot during running. Subject specific computer models of the foot were driven using the kinematics of eight subjects running at 3.1m/s using two initial contact patterns (rearfoot and non-rearfoot). These models were used to estimate PA strain, force, and elastic energy storage during the stance phase. To examine the release of stored energy, the foot joint moments, powers, and work created by the PA were computed. Mean elastic energy stored in the PA was 3.1±1.6J, which was comparable to in situ testing values. Changes to the initial contact pattern did not change elastic energy storage or late stance PA function, but did alter PA pre-tensioning and function during early stance. In both initial contact patterns conditions, the PA power was positive during late stance, which reveals that the release of the stored elastic energy assists with shortening of the arch during push-off. As the PA is just one of the arch׳s passive elastic tissues, the entire arch may store additional energy and impact the metabolic cost of running. Copyright © 2016 Elsevier Ltd. All rights reserved.

Development of an optically-based tension-indicating implanted orthopedic screw with a luminescent spectral ruler

NASA Astrophysics Data System (ADS)

Ravikumar, Nakul; Rogalski, Melissa M.; Benza, Donny; Lake, Joshua; Urban, Matthew; Pelham, Hunter; Anker, Jeffrey N.; DesJardins, John D.

2017-03-01

An orthopaedic screw was designed with an optical tension-indicator to non-invasively quantify screw tension and monitor the load sharing between the bone and the implant. The screw both applies load to the bone, and measures this load by reporting the strain on the screw. The screw contains a colorimetric optical encoder that converts axial strain into colorimetric changes visible through the head of the screw, or luminescent spectral changes that are detected through tissue. Screws were tested under cyclic mechanical loading to mimic in-vivo conditions to verify the sensitivity, repeatability, and reproducibility of the sensor. In the absence to tissue, color was measured using a digital camera as a function of axial load on a stainless steel cannulated (hollow) orthopedic screw, modified by adding a passive colorimetric strain gauge through the central hole. The sensor was able to quantify clinically-relevant bone healing strains. The sensor exhibited good repeatability and reproducibility but also displayed hysteresis due to the internal mechanics of the screw. The strain indicator was also modified for measurement through tissue by replacing the reflective colorimetric sensor with a low-background X-ray excited optical luminescence signal. Luminescent spectra were acquired through 6 mm of chicken breast tissue. Overall, this research shows feasibility for a unique device which quantifies the strain on an orthopedic screw. Future research will involve reducing hysteresis by changing the mechanism of strain transduction in the screw, miniaturizing the luminescent strain gauge, monitoring bending as well as tension, using alternative luminescent spectral rulers based upon near infrared fluorescence or upconversion luminescence, and application to monitoring changes in pretension and load sharing during bone healing.

Review of Cold war social science: Knowledge production, liberal democracy, and human nature, and Working knowledge: Making the human sciences from Parsons to Kuhn.

PubMed

Erickson, Paul

2013-11-01

Reviews the books, Cold War Social Science: Knowledge Production, Liberal Democracy, and Human Nature by Mark Solovey and Hamilton Cravens (2012) and Working Knowledge: Making the Human Sciences From Parsons to Kuhn by Joel Isaac (see record 2012-13212-000). Taken together, these two important books make intriguing statements about the way to write the histories of fields like psychology, sociology, anthropology, and economics in the Anglo American world during the 20th century. To date, histories of these fields have drawn on a number of fairly well-established punctuation marks to assist in periodization: the shift from interwar institutionalism in economics to postwar neoclassicism, with its physics-like emphasis on mathematical theory-building; the transition from the regnant prewar behaviorism through a postwar "cognitive revolution" in American psychology; and the move in fields like sociology and anthropology away from positivism and the pursuit of what has sometimes been called "grand theory" in the early postwar era toward a period defined by intellectual and political fragmentation, the reemergence of interpretive approaches and a reaction to the scientistic pretensions of the earlier period. These books, by contrast, provide perspectives orthogonal to such existing narrative frameworks by adopting cross-cutting lenses like the "Cold War" and the working practices of researchers in the social and behavioral sciences. As a result, they do much to indicate the value of casting a historiographical net beyond individual disciplines, or even beyond the "social sciences" or the "human sciences" sensu stricto, in the search for deeper patterns of historical development in these fields. (PsycINFO Database Record (c) 2013 APA, all rights reserved).

Diagnostic and statistical manual-5: Position paper of the Indian Psychiatric Society

PubMed Central

Jacob, K. S.; Kallivayalil, R. A.; Mallik, A. K.; Gupta, N.; Trivedi, J. K.; Gangadhar, B. N.; Praveenlal, K.; Vahia, V.; Rao, T. S. Sathyanarayana

2013-01-01

The development of the Diagnostic and Statistical Manual-5 (DSM-5) has been an exhaustive and elaborate exercise involving the review of DSM-IV categories, identifying new evidence and ideas, field testing, and revising issues in order that it is based on the best available evidence. This report of the Task Force of the Indian Psychiatric Society examines the current draft of the DSM-5 and discusses the implications from an Indian perspective. It highlights the issues related to the use of universal categories applied across diverse cultures. It reiterates the evidence for mental disorders commonly seen in India. It emphasizes the need for caution when clinical categories useful to specialists are employed in the contexts of primary care and in community settings. While the DSM-5 is essentially for the membership of the American Psychiatric Association, its impact will be felt far beyond the boundaries of psychiatry and that of the United States of America. However, its atheoretical approach, despite its pretensions, pushes a purely biomedical agenda to the exclusion of other approaches to mental health and illness. Nevertheless, the DSM-5 should serve a gate-keeping function, which intends to set minimum standards. It is work in progress and will continue to evolve with the generation of new evidence. For the DSM-5 to be relevant and useful across the cultures and countries, it needs to be broad-based and consider social and cultural contexts, issues, and phenomena. The convergence and compatibility with International Classification of Diseases-11 is a worthy goal. While the phenomenal effort of the DSM-5 revision is commendable, psychiatry should continue to strive for a more holistic understanding of mental health, illness, and disease. PMID:23441009

Normal impact of a low-velocity projectile against a taut string-like membrane

NASA Astrophysics Data System (ADS)

Zhao, Yifei; Sun, Zhili

2018-07-01

For the impact system in which a moving projectile transversely impacts against a taut fabric band, 1-D linearized model applies because of low-velocity, sufficient pretension, and the sizes of the objects. This projectile-to-band impact model can serve as the physical prototype of applications in engineering such as cable-membrane architectures and seat belts. In this fundamental work, the response properties under central and non-central impacts are investigated analytically from the viewpoint of wave propagations, while comparisons and verifications are made with finite element (FE) analysis. For a central impact after the first separation, band can catch up with the projectile such that a contact-impact state is re-established when m is in the small interval neighbouring m = 1. For a non-central impact, the projectile would be subjected to a combination of translation and rotation due to asymmetric wave propagations. From every certain instant, the projectile is subjected to an additional rotational acceleration (principal moment) with an abrupt or zero initial value in the anti-clockwise or clockwise direction. The swing amplitude of a small-j or a flat projectile is susceptible to significant fluctuations, and vice versa. The band with a rather large off-centre ratio for the impacted zone and a rather short length of the shorter segment would facilitate a larger accumulation of swing amplitude in a single direction soon after the impact. The linearized impact models proposed can be used to well describe the small-deflection responses for the system, based on 1-D wave propagations or the dependence of quasi-static band deflection on time if the impact duration is much longer than the double wave transit time for the band.

Predicting Rib Fracture Risk With Whole-Body Finite Element Models: Development and Preliminary Evaluation of a Probabilistic Analytical Framework

PubMed Central

Forman, Jason L.; Kent, Richard W.; Mroz, Krystoffer; Pipkorn, Bengt; Bostrom, Ola; Segui-Gomez, Maria

2012-01-01

This study sought to develop a strain-based probabilistic method to predict rib fracture risk with whole-body finite element (FE) models, and to describe a method to combine the results with collision exposure information to predict injury risk and potential intervention effectiveness in the field. An age-adjusted ultimate strain distribution was used to estimate local rib fracture probabilities within an FE model. These local probabilities were combined to predict injury risk and severity within the whole ribcage. The ultimate strain distribution was developed from a literature dataset of 133 tests. Frontal collision simulations were performed with the THUMS (Total HUman Model for Safety) model with four levels of delta-V and two restraints: a standard 3-point belt and a progressive 3.5–7 kN force-limited, pretensioned (FL+PT) belt. The results of three simulations (29 km/h standard, 48 km/h standard, and 48 km/h FL+PT) were compared to matched cadaver sled tests. The numbers of fractures predicted for the comparison cases were consistent with those observed experimentally. Combining these results with field exposure informantion (ΔV, NASS-CDS 1992–2002) suggests a 8.9% probability of incurring AIS3+ rib fractures for a 60 year-old restrained by a standard belt in a tow-away frontal collision with this restraint, vehicle, and occupant configuration, compared to 4.6% for the FL+PT belt. This is the first study to describe a probabilistic framework to predict rib fracture risk based on strains observed in human-body FE models. Using this analytical framework, future efforts may incorporate additional subject or collision factors for multi-variable probabilistic injury prediction. PMID:23169122

Pretense of parentage by siblings in immigration: Polesky's paradox reconsidered.

PubMed

Wenk, Robert E; Shao, Alison

2014-02-01

Older and younger siblings occasionally attempt to impersonate parent and child to expedite immigration under US family-based visa policies. The rate with which full siblings escape detection by current relationship tests is unknown. Retrospective study of full-sibling immigrant pairs was undertaken to determine the proportion that show insufficient genetic evidence to exclude parentage. Sibship and parentage indices (SI and PI) were compared/case in unexcluded sibling cases and true parent-child cases. Alleles shared per short-tandem-repeat locus were compared in sibling and parent-child pairs. The proportion of successful parentage fraud by siblings was estimated from the parentage exclusion rate among immigrants and the proportion of sibships without genetic inconsistencies (GIs). When 11 to 25 independent loci were tested per two-sibling case to verify or refute parentage, tests failed to demonstrate any GI in 9% and PI was greater than SI in seven of 10 of these cases. Another 29% of full-sibling pairs demonstrated insufficient evidence (fewer than two GIs) to exclude parentage. Thus, 0.4% of sibling pairs could falsely claim a parent-child relationship and show no GIs. Another 1.4% could make that false claim and not present sufficient evidence to be excluded. At present, with no evidence of parentage exclusion in a full-sibling pair, the relative magnitudes of PI and SI are misleading relationship indicators because too few loci are examined and rates of sharing one and two alleles/locus vary greatly in parentage and sibling pairs. Only evidence of exclusion ascertains false parentage claims by siblings. Nevertheless, the expected rate of successful fraud is quite low. © 2013 American Association of Blood Banks.

Verification of predicted specimen-specific natural and implanted patellofemoral kinematics during simulated deep knee bend.

PubMed

Baldwin, Mark A; Clary, Chadd; Maletsky, Lorin P; Rullkoetter, Paul J

2009-10-16

Verified computational models represent an efficient method for studying the relationship between articular geometry, soft-tissue constraint, and patellofemoral (PF) mechanics. The current study was performed to evaluate an explicit finite element (FE) modeling approach for predicting PF kinematics in the natural and implanted knee. Experimental three-dimensional kinematic data were collected on four healthy cadaver specimens in their natural state and after total knee replacement in the Kansas knee simulator during a simulated deep knee bend activity. Specimen-specific FE models were created from medical images and CAD implant geometry, and included soft-tissue structures representing medial-lateral PF ligaments and the quadriceps tendon. Measured quadriceps loads and prescribed tibiofemoral kinematics were used to predict dynamic kinematics of an isolated PF joint between 10 degrees and 110 degrees femoral flexion. Model sensitivity analyses were performed to determine the effect of rigid or deformable patellar representations and perturbed PF ligament mechanical properties (pre-tension and stiffness) on model predictions and computational efficiency. Predicted PF kinematics from the deformable analyses showed average root mean square (RMS) differences for the natural and implanted states of less than 3.1 degrees and 1.7 mm for all rotations and translations. Kinematic predictions with rigid bodies increased average RMS values slightly to 3.7 degrees and 1.9 mm with a five-fold decrease in computational time. Two-fold increases and decreases in PF ligament initial strain and linear stiffness were found to most adversely affect kinematic predictions for flexion, internal-external tilt and inferior-superior translation in both natural and implanted states. The verified models could be used to further investigate the effects of component alignment or soft-tissue variability on natural and implant PF mechanics.

Purification and Characterization of Four β-Expansins (Zea m 1 Isoforms) from Maize Pollen1[w

PubMed Central

Li, Lian-Chao; Bedinger, Patricia A.; Volk, Carol; Jones, A. Daniel; Cosgrove, Daniel J.

2003-01-01

Four proteins with wall extension activity on grass cell walls were purified from maize (Zea mays) pollen by conventional column chromatography and high-performance liquid chromatography. Each is a basic glycoprotein (isoelectric point = 9.1–9.5) of approximately 28 kD and was identified by immunoblot analysis as an isoform of Zea m 1, the major group 1 allergen of maize pollen and member of the β-expansin family. Four distinctive cDNAs for Zea m 1 were identified by cDNA library screening and by GenBank analysis. One pair (GenBank accession nos. AY104999 and AY104125) was much closer in sequence to well-characterized allergens such as Lol p 1 and Phl p 1 from ryegrass (Lolium perenne) and Phleum pretense, whereas a second pair was much more divergent. The N-terminal sequence and mass spectrometry fingerprint of the most abundant isoform (Zea m 1d) matched that predicted for AY197353, whereas N-terminal sequences of the other isoforms matched or nearly matched AY104999 and AY104125. Highly purified Zea m 1d induced extension of a variety of grass walls but not dicot walls. Wall extension activity of Zea m 1d was biphasic with respect to protein concentration, had a broad pH optimum between 5 and 6, required more than 50 μg mL-1 for high activity, and led to cell wall breakage after only approximately 10% extension. These characteristics differ from those of α-expansins. Some of the distinctive properties of Zea m 1 may not be typical of β-expansins as a class but may relate to the specialized function of this β-expansin in pollen function. PMID:12913162

Biodegradation of Mixed PAHs by PAH-Degrading Endophytic Bacteria.

PubMed

Zhu, Xuezhu; Ni, Xue; Waigi, Michael Gatheru; Liu, Juan; Sun, Kai; Gao, Yanzheng

2016-08-09

Endophytic bacteria can promote plant growth, induce plant defence mechanisms, and increase plant resistance to organic contaminants. The aims of the present study were to isolate highly PAH-degrading endophytic bacteria from plants growing at PAH-contaminated sites and to evaluate the capabilities of these bacteria to degrade polycyclic aromatic hydrocarbons (PAHs) in vitro, which will be beneficial for re-colonizing target plants and reducing plant PAH residues through the inoculation of plants with endophytic bacteria. Two endophytic bacterial strains P₁ (Stenotrophomonas sp.) and P₃ (Pseudomonas sp.), which degraded more than 90% of phenanthrene (PHE) within 7 days, were isolated from Conyza canadensis and Trifolium pretense L., respectively. Both strains could use naphthalene (NAP), PHE, fluorene (FLR), pyrene (PYR), and benzo(a)pyrene (B(a)P) as the sole sources of carbon and energy. Moreover, these bacteria reduced the contamination of mixed PAHs at high levels after inoculation for 7 days; strain P₁ degraded 98.0% NAP, 83.1% FLR, 87.8% PHE, 14.4% PYR, and 1.6% B(a)P, and strain P₃ degraded 95.3% NAP, 87.9% FLR, 90.4% PHE, 6.9% PYR, and negligible B(a)P. Notably, the biodegradation of PAHs could be promoted through additional carbon and nitrogen nutrients; therein, beef extract was suggested as the optimal co-substrate for the degradation of PAHs by these two strains (99.1% PHE was degraded within 7 days). Compared with strain P₁, strain P₃ has more potential for the use in the removal of PAHs from plant tissues. These results provide a novel perspective in the reduction of plant PAH residues in PAH-contaminated sites through inoculating plants with highly PAH-degrading endophytic bacteria.

Room-Temperature Pressure-Induced Optically-Actuated Fabry-Perot Nanomechanical Resonator with Multilayer Graphene Diaphragm in Air.

PubMed

Li, Cheng; Lan, Tian; Yu, Xiyu; Bo, Nan; Dong, Jingyu; Fan, Shangchun

2017-11-04

We demonstrated a miniature and in situ ~13-layer graphene nanomechanical resonator by utilizing a simple optical fiber Fabry-Perot (F-P) interferometric excitation and detection scheme. The graphene film was transferred onto the endface of a ferrule with a 125-μm inner diameter. In contrast to the pre-tension induced in membrane that increased quality ( Q ) factor to ~18.5 from ~3.23 at room temperature and normal pressure, the limited effects of air damping on resonance behaviors at 10 -2 and 10⁵ Pa were demonstrated by characterizing graphene F-P resonators with open and micro-air-gap cavities. Then in terms of optomechanical behaviors of the resonator with an air micro-cavity configuration using a polished ferrule substrate, measured resonance frequencies were increased to the range of 509-542 kHz from several kHz with a maximum Q factor of 16.6 despite the lower Knudsen number ranging from 0.0002 to 0.0006 in damping air over a relative pressure range of 0-199 kPa. However, there was the little dependence of Q on resonance frequency. Note that compared with the inferior F-P cavity length response to applied pressures due to interfacial air leakage, the developed F-P resonator exhibited a consistent fitted pressure sensitivity of 1.18 × 10⁵ kHz³/kPa with a good linearity error of 5.16% in the tested range. These measurements shed light on the pre-stress-dominated pressure-sensitive mechanisms behind air damping in in situ F-P resonant sensors using graphene or other 2D nanomaterials.

EFFECT OF AXIAL TIBIAL TORQUE DIRECTION ON ACL RELATIVE STRAIN AND STRAIN RATE IN AN IN VITRO SIMULATED PIVOT LANDING

PubMed Central

Oh, Youkeun K.; Kreinbrink, Jennifer L.; Wojtys, Edward M.; Ashton-Miller, James A.

2011-01-01

Anterior cruciate ligament (ACL) injuries most frequently occur under the large loads associated with a unipedal jump landing involving a cutting or pivoting maneuver. We tested the hypotheses that internal tibial torque would increase the anteromedial (AM) bundle ACL relative strain and strain rate more than would the corresponding external tibial torque under the large impulsive loads associated with such landing maneuvers. Twelve cadaveric female knees [mean (SD) age: 65.0 (10.5) years] were tested. Pretensioned quadriceps, hamstring and gastrocnemius muscle-tendon unit forces maintained an initial knee flexion angle of 15°. A compound impulsive test load (compression, flexion moment and internal or external tibial torque) was applied to the distal tibia while recording the 3-D knee loads and tibofemoral kinematics. AM-ACL relative strain was measured using a 3mm DVRT. In this repeated measures experiment, the Wilcoxon Signed-Rank test was used to test the null hypotheses with p<0.05 considered significant. The mean (± SD) peak AM-ACL relative strains were 5.4±3.7 % and 3.1±2.8 % under internal and external tibial torque, respectively. The corresponding mean (± SD) peak AM-ACL strain rates reached 254.4±160.1 %/sec and 179.4±109.9 %/sec, respectively. The hypotheses were supported in that the normalized mean peak AM-ACL relative strain and strain rate were 70% and 42% greater under internal than external tibial torque, respectively (p=0.023, p=0.041). We conclude that internal tibial torque is a potent stressor of the ACL because it induces a considerably (70%) larger peak strain in the AM-ACL than does a corresponding external tibial torque. PMID:22025178

Early social cognition in three cultural contexts.

PubMed

Callaghan, Tara; Moll, Henrike; Rakoczy, Hannes; Warneken, Felix; Liszkowski, Ulf; Behne, Tanya; Tomasello, Michael

2011-08-01

The influence of culture on cognitive development is well established for school age and older children. But almost nothing is known about how different parenting and socialization practices in different cultures affect infants' and young children's earliest emerging cognitive and social-cognitive skills. In the current monograph, we report a series of eight studies in which we systematically assessed the social-cognitive skills of 1- to 3-year-old children in three diverse cultural settings. One group of children was from a Western, middle-class cultural setting in rural Canada and the other two groups were from traditional, small-scale cultural settings in rural Peru and India.In a first group of studies, we assessed 1-year-old children's most basic social-cognitive skills for understanding the intentions and attention of others: imitation, helping, gaze following, and communicative pointing.Children's performance in these tasks was mostly similar across cultural settings. In a second group of studies, we assessed 1-year-old children's skills in participating in interactive episodes of collaboration and joint attention.Again in these studies the general finding was one of cross-cultural similarity. In a final pair of studies, we assessed 2- to 3-year-old children's skills within two symbolic systems (pretense and pictorial). Here we found that the Canadian children who had much more experience with such symbols showed skills at an earlier age.Our overall conclusion is that young children in all cultural settings get sufficient amounts of the right kinds of social experience to develop their most basic social-cognitive skills for interacting with others and participating in culture at around the same age. In contrast, children's acquisition of more culturally specific skills for use in practices involving artifacts and symbols is more dependent on specific learning experiences.

Effect of axial tibial torque direction on ACL relative strain and strain rate in an in vitro simulated pivot landing.

PubMed

Oh, Youkeun K; Kreinbrink, Jennifer L; Wojtys, Edward M; Ashton-Miller, James A

2012-04-01

Anterior cruciate ligament (ACL) injuries most frequently occur under the large loads associated with a unipedal jump landing involving a cutting or pivoting maneuver. We tested the hypotheses that internal tibial torque would increase the anteromedial (AM) bundle ACL relative strain and strain rate more than would the corresponding external tibial torque under the large impulsive loads associated with such landing maneuvers. Twelve cadaveric female knees [mean (SD) age: 65.0 (10.5) years] were tested. Pretensioned quadriceps, hamstring, and gastrocnemius muscle-tendon unit forces maintained an initial knee flexion angle of 15°. A compound impulsive test load (compression, flexion moment, and internal or external tibial torque) was applied to the distal tibia while recording the 3D knee loads and tibofemoral kinematics. AM-ACL relative strain was measured using a 3 mm DVRT. In this repeated measures experiment, the Wilcoxon signed-rank test was used to test the null hypotheses with p < 0.05 considered significant. The mean (±SD) peak AM-ACL relative strains were 5.4 ± 3.7% and 3.1 ± 2.8% under internal and external tibial torque, respectively. The corresponding mean (± SD) peak AM-ACL strain rates reached 254.4 ± 160.1%/s and 179.4 ± 109.9%/s, respectively. The hypotheses were supported in that the normalized mean peak AM-ACL relative strain and strain rate were 70 and 42% greater under internal than under external tibial torque, respectively (p = 0.023, p = 0.041). We conclude that internal tibial torque is a potent stressor of the ACL because it induces a considerably (70%) larger peak strain in the AM-ACL than does a corresponding external tibial torque. Copyright © 2011 Orthopaedic Research Society.

Material Properties Analysis of Structural Members in Pumpkin Balloons

NASA Technical Reports Server (NTRS)

Sterling, W. J.

2003-01-01

The efficient design, service-life qualification, and reliability predictions for lightweight aerospace structures require careful mechanical properties analysis of candidate structural materials. The demand for high-quality laboratory data is particularly acute when the candidate material or the structural design has little history. The pumpkin-shaped super-pressure balloon presents both challenges. Its design utilizes load members (tendons) extending from apex to base around the gas envelope to achieve a lightweight structure. The candidate tendon material is highly weight-efficient braided HM cord. Previous mechanical properties studies of Zylon have focused on fiber and yarn, and industrial use of the material in tensile applications is limited. For high-performance polymers, a carefully plamed and executed properties analysis scheme is required to ensure the data are relevant to the desired application. Because no directly-applicable testing standard was available, a protocol was developed based on guidelines fiom professional and industry organizations. Due to the liquid-crystalline nature of the polymer, the cord is very stiff, creeps very little, and does not yield. Therefore, the key material property for this application is the breaking strength. The pretension load and gauge length were found to have negligible effect on the measured breaking strength over the ranges investigated. Strain rate was found to have no effect on breaking strength, within the range of rates suggested by the standards organizations. However, at the lower rate more similar to ULDB operations, the strength was reduced. The breaking strength increased when the experiment temperature was decreased from ambient to 183K which is the lowest temperature ULDB is expected to experience. The measured strength under all test conditions was well below that resulting from direct scale-up of fiber strength based on the manufacturers data. This expected result is due to the effects of the braiding process and material ageing.

Phytoestrogens and Their Metabolites in Bulk-Tank Milk: Effects of Farm Management and Season

PubMed Central

Adler, Steffen A.; Purup, Stig; Hansen-Møller, Jens; Thuen, Erling; Steinshamn, Håvard

2015-01-01

Phytoestrogens have structures similar to endogenous steroids and may induce or inhibit the response of hormone receptors. The objectives of the present study were to compare the effects of long-term vs. short-term grassland management in organic and conventional dairy production systems, compare organic and conventional production systems and assess seasonal variation on phytoestrogen concentrations in bulk-tank milk. The concentrations of phytoestrogens were analyzed in bulk-tank milk sampled three times in two subsequent years from 28 dairy farms: Fourteen organic (ORG) dairy farms with either short-term or long-term grassland management were paired with 14 conventional (CON) farms with respect to grassland management. Grassland management varied in terms of time since establishment. Short-term grassland management (SG) was defined as establishment or reseeding every fourth year or more often, and long-term grassland management (LG) was defined as less frequent establishment or reseeding. The proportion of red clover (Trifolium pretense L.) in the herbage was positively correlated with milk concentrations of the mammalian isoflavone equol. Therefore, organically produced bulk-tank milk contained more equol than conventionally produced milk, and milk from ORG-SG farms had more equol than milk from ORG-LG farms. Milk produced during the indoor-feeding periods had more equol than milk produced during the outdoor feeding period, because pastures contained less red clover than fields intended for silage production. Organically produced milk had also higher concentrations of the mammalian lignan enterolactone, but in contrast to equol, concentrations increased in the outdoor-feeding periods compared to the indoor-feeding periods. There were no indications of fertility problems on ORG-SG farms who had the highest red clover proportions in the herbage. This study shows that production system, grassland management, and season affect milk concentrations of phytoestrogens. However, compared to soy products, milk concentrations of phytoestrogens are low and future studies are required to investigate if the intake of phytoestrogens from dairy products has physiological effects in humans. PMID:25996600

Finite element modeling of temperature load effects on the vibration of local modes in multi-cable structures

NASA Astrophysics Data System (ADS)

Treyssède, Fabien

2018-01-01

Understanding thermal effects on the vibration of local (cable-dominant) modes in multi-cable structures is a complicated task. The main difficulty lies in the modification by temperature change of cable tensions, which are then undetermined. This paper applies a finite element procedure to investigate the effects of thermal loads on the linear dynamics of prestressed self-weighted multi-cable structures. Provided that boundary conditions are carefully handled, the discretization of cables with nonlinear curved beam elements can properly represent the thermoelastic behavior of cables as well as their linearized dynamics. A three-step procedure that aims to replace applied pretension forces with displacement continuity conditions is used. Despite an increase in the computational cost related to beam rotational degrees of freedom, such an approach has several advantages. Nonlinear beam finite elements are usually available in commercial codes. The overall method follows a thermoelastic geometrically non-linear analysis and hereby includes the main sources of non-linearities in multi-cable structures. The effects of cable bending stiffness, which can be significant, are also naturally accounted for. The accuracy of the numerical approach is assessed thanks to an analytical model for the vibration of a single inclined cable under temperature change. Then, the effects of thermal loads are investigated for two cable bridges, highlighting how natural frequencies can be affected by temperature. Although counterintuitive, a reverse relative change of natural frequency may occur for certain local modes. This phenomenon can be explained by two distinct mechanisms, one related to the physics intrinsic to cables and the other related to the thermal deflection of the superstructure. Numerical results show that cables cannot be isolated from the rest of the structure and the importance of modeling the whole structure for a quantitative analysis of temperature effects on the dynamics of cable bridges.

Virtue or Pretense? Looking behind Self-Declared Innocence in Doping

PubMed Central

Petróczi, Andrea; Aidman, Eugene V.; Hussain, Iltaf; Deshmukh, Nawed; Nepusz, Tamás; Uvacsek, Martina; Tóth, Miklós; Barker, James; Naughton, Declan P.

2010-01-01

Background Social science studies of doping practices in sport rely predominantly on self-reports. Studies of psychoactive drug use indicate that self-reporting is characterised by under-reporting. Likewise doping practice is likely to be equally under-reported, if not more so. This calls for more sophisticated methods for such reporting and for independent, objective validation of its results. The aims of this study were: i) to contrast self-reported doping use with objective results from chemical hair analysis and ii) to investigate the influence of the discrepancy on doping attitudes, social projection, descriptive norms and perceived pressure to use doping. Methodology/Principal Findings A doping attitudes questionnaire was developed and combined with a response latency-based implicit association test and hair sample analysis for key doping substances in 14 athletes selected from a larger sample (N = 82) to form contrast comparison groups. Results indicate that patterns of group differences in social projection, explicit attitude about and perceived pressure to use doping, vary depending on whether the user and non-user groups are defined by self-report or objectively verified through hair analysis. Thus, self-confessed users scored higher on social projection, explicit attitude to doping and perceived pressure. However, when a doping substance was detected in the hair of an athlete who denied doping use, their self-report evidenced extreme social desirability (negative attitude, low projection and low perceived pressure) and contrasted sharply with a more positive estimate of their implicit doping attitude. Conclusions/Significance Hair analysis for performance enhancing substances has shown considerable potential in validating athletes' doping attitude estimations and admissions of use. Results not only confirm the need for improved self-report methodology for future research in socially-sensitive domains but also indicate where the improvements are likely to come from: as chemical validation remains expensive, a more realistic promise for large scale studies and online data collection efforts is held by measures of implicit social cognition. PMID:20463978

Morphologic Characteristics Help Explain the Gender Difference in Peak Anterior Cruciate Ligament Strain During a Simulated Pivot Landing

PubMed Central

Lipps, David B.; Oh, Youkeun K.; Ashton-Miller, James A.; Wojtys, Edward M.

2015-01-01

Background Gender differences exist in anterior cruciate ligament (ACL) cross-sectional area and lateral tibial slope. Biomechanical principles suggest that the direction of these gender differences should induce larger peak ACL strains in females under dynamic loading. Hypothesis Peak ACL relative strain during a simulated pivot landing is significantly greater in female ACLs than male ACLs. Study Design Controlled laboratory study. Methods Twenty cadaveric knees from height- and weight-matched male and female cadavers were subjected to impulsive 3-dimensional test loads of 2 times body weight in compression, flexion, and internal tibial torque starting at 15° of flexion. Load cells measured the 3-dimensional forces and moments applied to the knee, and forces in the pretensioned quadriceps, hamstring, and gastrocnemius muscle equivalents. A novel, gender-specific, nonlinear spring simulated short-range and longer range quadriceps muscle tensile stiffness. Peak relative strain in the anteromedial bundle of the ACL (AM-ACL) was measured using a differential variable reluctance transducer, while ACL cross-sectional area and lateral tibial slope were measured using magnetic resonance imaging. A repeated-measures Mann-Whitney signed-rank test was used to test the hypothesis. Results Female knees exhibited 95% greater peak AM-ACL relative strain than male knees (6.37% [22.53%] vs 3.26% [11.89%]; P = .004). Anterior cruciate ligament cross-sectional area and lateral tibial slope were significant predictors of peak AM-ACL relative strain (R2 = .59; P = .001). Conclusion Peak AM-ACL relative strain was significantly greater in female than male knees from donors of the same height and weight. This gender difference is attributed to a smaller female ACL cross-sectional area and a greater lateral tibial slope. Clinical Relevance Since female ACLs are systematically exposed to greater strain than their male counterparts, training and injury prevention programs should take this fact into consideration. PMID:21917612

Nb3Sn superconducting magnets for electron cyclotron resonance ion sources.

PubMed

Ferracin, P; Caspi, S; Felice, H; Leitner, D; Lyneis, C M; Prestemon, S; Sabbi, G L; Todd, D S

2010-02-01

Electron cyclotron resonance (ECR) ion sources are an essential component of heavy-ion accelerators. Over the past few decades advances in magnet technology and an improved understanding of the ECR ion source plasma physics have led to remarkable performance improvements of ECR ion sources. Currently third generation high field superconducting ECR ion sources operating at frequencies around 28 GHz are the state of the art ion injectors and several devices are either under commissioning or under design around the world. At the same time, the demand for increased intensities of highly charged heavy ions continues to grow, which makes the development of even higher performance ECR ion sources a necessity. To extend ECR ion sources to frequencies well above 28 GHz, new magnet technology will be needed in order to operate at higher field and force levels. The superconducting magnet program at LBNL has been developing high field superconducting magnets for particle accelerators based on Nb(3)Sn superconducting technology for several years. At the moment, Nb(3)Sn is the only practical conductor capable of operating at the 15 T field level in the relevant configurations. Recent design studies have been focused on the possibility of using Nb(3)Sn in the next generation of ECR ion sources. In the past, LBNL has worked on the VENUS ECR, a 28 GHz source with solenoids and a sextupole made with NbTi operating at fields of 6-7 T. VENUS has now been operating since 2004. We present in this paper the design of a Nb(3)Sn ECR ion source optimized to operate at an rf frequency of 56 GHz with conductor peak fields of 13-15 T. Because of the brittleness and strain sensitivity of Nb(3)Sn, particular care is required in the design of the magnet support structure, which must be capable of providing support to the coils without overstressing the conductor. In this paper, we present the main features of the support structure, featuring an external aluminum shell pretensioned with water-pressurized bladders, and we analyze the expected coil stresses with a two-dimensional finite element mechanical model.

Nonlinear Structural Analysis Methodology and Dynamics Scaling of Inflatable Parabolic Reflector Antenna Concepts

NASA Technical Reports Server (NTRS)

Sreekantamurthy, Tham; Gaspar, James L.; Mann, Troy; Behun, Vaughn; Pearson, James C., Jr.; Scarborough, Stephen

2007-01-01

Ultra-light weight and ultra-thin membrane inflatable antenna concepts are fast evolving to become the state-of-the-art antenna concepts for deep-space applications. NASA Langley Research Center has been involved in the structural dynamics research on antenna structures. One of the goals of the research is to develop structural analysis methodology for prediction of the static and dynamic response characteristics of the inflatable antenna concepts. This research is focused on the computational studies to use nonlinear large deformation finite element analysis to characterize the ultra-thin membrane responses of the antennas. Recently, structural analyses have been performed on a few parabolic reflector antennas of varying size and shape, which are referred in the paper as 0.3 meters subscale, 2 meters half-scale, and 4 meters full-scale antenna. The various aspects studied included nonlinear analysis methodology and solution techniques, ways to speed convergence in iterative methods, the sensitivities of responses with respect to structural loads, such as inflation pressure, gravity, and pretension loads in the ground and in-space conditions, and the ultra-thin membrane wrinkling characteristics. Several such intrinsic aspects studied have provided valuable insight into evaluation of structural characteristics of such antennas. While analyzing these structural characteristics, a quick study was also made to assess the applicability of dynamics scaling of the half-scale antenna. This paper presents the details of the nonlinear structural analysis results, and discusses the insight gained from the studies on the various intrinsic aspects of the analysis methodology. The predicted reflector surface characteristics of the three inflatable ultra-thin membrane parabolic reflector antenna concepts are presented as easily observable displacement fringe patterns with associated maximum values, and normal mode shapes and associated frequencies. Wrinkling patterns are presented to show how surface wrinkle progress with increasing tension loads. Antenna reflector surface accuracies were found to be very much dependent on the type and size of the antenna, the reflector surface curvature, reflector membrane supports in terms of spacing of catenaries, as well as the amount of applied load.

What Strains the Anterior Cruciate Ligament During a Pivot Landing?

PubMed Central

Oh, Youkeun K.; Lipps, David B.; Ashton-Miller, James A.; Wojtys, Edward M.

2015-01-01

Background The relative contributions of an axial tibial torque and frontal plane moment to anterior cruciate ligament (ACL) strain during pivot landings are unknown. Hypothesis The peak normalized relative strain in the anteromedial (AM) bundle of the ACL is affected by the direction of the axial tibial torque but not by the direction of the frontal plane moment applied concurrently during a simulated jump landing. Study Design Controlled and descriptive laboratory studies. Methods Fifteen adult male knees with pretensioned knee muscle-tendon unit forces were loaded under a simulated pivot landing test. Compression, flexion moment, internal or external tibial torque, and knee varus or valgus moment were simultaneously applied to the distal tibia while recording the 3D knee loads and tibiofemoral kinematics. The AM-ACL relative strain was measured using a 3-mm differential variable reluctance transducer. The results were analyzed using nonparametric Wilcoxon signed–rank tests. A 3D dynamic biomechanical knee model was developed using ADAMS and validated to help interpret the experimental results. Results The mean (SD) peak AM-ACL relative strain was 192% greater (P <.001) under the internal tibial torque combined with a knee varus or valgus moment (7.0% [3.9%] and 7.0% [4.1%], respectively) than under external tibial torque with the same moments (2.4% [2.5%] and 2.4% [3.2%], respectively). The knee valgus moment augmented the AM-ACL strain due to the slope of the tibial plateau inducing mechanical coupling (ie, internal tibial rotation and knee valgus moment); this augmentation occurred before medial knee joint space opening. Conclusion An internal tibial torque combined with a knee valgus moment is the worst-case ACL loading condition. However, it is the internal tibial torque that primarily causes large ACL strain. Clinical Relevance Limiting the maximum coefficient of friction between the shoe and playing surface should limit the peak internal tibial torque that can be applied to the knee during jump landings, thereby reducing peak ACL strain and the risk for noncontact injury. PMID:22223717

A GPR system for the high-resolution inspection of walls and structures

NASA Astrophysics Data System (ADS)

Manacorda, Guido; Simi, Alessandro; Barsacchi, Giorgio

2014-05-01

Nowadays GPR systems are used in a broad range of applications, including the non-destructive inspection of man-made concrete structures such as pillars and bridge decks. Concrete inspection involves several aspects including: location of reinforced bars in walls and floors, concrete condition assessment, concrete cover detection, etc. These surveys are very demanding as far as the system is concerned, because of the strict requirements in terms of resolution and accuracy. Specifically, a key GPR application concerns the condition assessment of a structure that has undergone rehabilitation (e.g. for the removal of architectural barriers or new openings); in this case, the current practice requires to re-check the stability of the entire structure that includes the identification of the number of rebars in reinforced concrete beams location of pre-tensioned cables and early detection of corrosion. This can be done by verification holes (coring) that is costly and intrusive practice or by using a pachometer, but this tool has a limited field of investigation (up to 7-8 cm from the surface). GPR can instead be a useful investigative tool especially when the surface of the beam is not accessible because it is covered by screed or floor. The need of detecting rebars with diameter in the millimeter range as well as the identification of small cavities and cracks, require the development of GPR antennas featuring linear phase and constant polarization, and capable to radiate a very short pulse (i.e. with a duration in the order of few hundreds of picosecond) with no ring-down in order to achieve a high range resolution. A novel 3 GHz center frequency antenna has been recently developed and tested; it has been found capable of providing a very clear image of the concrete internal structure that helps in locating targets and enables an early detection of damages, thus providing a fast and efficient maintenance of the structure itself. The Authors thank COST for funding COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar".

Ethnomycological study in the Kilum-Ijim mountain forest, Northwest Region, Cameroon.

PubMed

Teke, N A; Kinge, T R; Bechem, E; Nji, T M; Ndam, L M; Mih, A M

2018-04-02

Majority of the people in rural areas depend on traditional fungi-based medicines to combat different illnesses. This ethnomycological survey was undertaken to document the traditional knowledge of mushrooms among the communities in the Kilum-Ijim mountain forest reserve. Although macrofungi are exploited for food and medicine, their ethnomycological knowledge has not been documented in this ecosystem. A field study was carried out between 2014 and 2015; 14 mushrooms used by the local communities were collected and identified using the polymorphism of the ribosomal ITS1, 5.8S, and ITS2 regions. Semi-structured questionnaires, focus group discussions, and pictorial method were used to collect information on edibility, local names, indigenous knowledge, and the role of macrofungi in ten communities. Ethnomycological findings revealed that mushrooms were used as food and medicine, while the non-edible species were regarded as food from Satan. Eight species, Polyporus tenuiculus, Termitomyces striatus, Termitomyces microcarpus Auricularia polytricha, Laetiporus sulphureus, Termitomyces sp.1, Termitomyces sp.2, and Polyporus dictyopus, were reported as edible and Auricularia polytricha, Daldinia concentrica, Ganoderma applanatum, Lentinus squarrosulus, Polyporus dictyopus, Termitomyces microcarpus, Trametes versicolor, Vascellum pretense and Xylaria sp., were used as medicine in traditional health care. Local names were found to be a very important factor in distinguishing between edible, medicinal, and poisonous mushrooms. Edible mushrooms are called "awo'oh" in Belo and "Kiwoh" in Oku. Poisonous mushrooms were commonly referred to as "awo'oh Satan" in Belo and "Kiwohfiyini" in Oku. Mushrooms were highly valued as a source of protein and as a substitute for meat in their diets. It is worth noting that Polyporus dictyopus was reported here for the first time in literature as an edible mushroom species. Local knowledge of medicinal mushrooms in the treatment of different illness still exists in all ten villages surveyed. Elderly men and women appear to play an important role in primary health care services in these communities. This survey underscores the need to preserve and document traditional knowledge of the different medicinal mushrooms used in treating different illnesses and for more future scientific research on the mushrooms to determine their efficacy and their safety.

Molecular structure, spectral investigation (1H NMR, 13C NMR, UV-Visible, FT-IR, FT-Raman), NBO, intramolecular hydrogen bonding, chemical reactivity and first hyperpolarizability analysis of formononetin [7-hydroxy-3(4-methoxyphenyl)chromone]: A quantum chemical study

NASA Astrophysics Data System (ADS)

Srivastava, Anubha; Mishra, Rashmi; Kumar, Sudhir; Dev, Kapil; Tandon, Poonam; Maurya, Rakesh

2015-03-01

Formononetin [7-hydroxy-3(4-methoxyphenyl)chromone or 4‧-methoxy daidzein] is a soy isoflavonoid that is found abundantly in traditional Chinese medicine Astragalus mongholicus (Bunge) and Trifolium pretense L. (red clover), and in an Indian medicinal plant, Butea (B.) monosperma. Crude extract of B.monosperma is used for rapid healing of fracture in Indian traditional medicine. In this study, a combined theoretical and experimental approach is used to study the properties of formononetin. The optimized geometry was calculated by B3LYP method using 6-311++G(d,p) as a large basis set. The FT-Raman and FT-IR spectra were recorded in the solid phase, and interpreted in terms of potential energy distribution (PED) analysis. Density functional theory (DFT) is applied to explore the nonlinear optical properties of the molecule. Good consistency is found between the calculated results and observed data for the electronic absorption, IR and Raman spectra. The solvent effects have been calculated using time-dependent density functional theory in combination with the integral equation formalism polarized continuum model, and the results are in good agreement with observed measurements. The double well potential energy curve of the molecule about the respective bonds, have been plotted, as obtained from DFT/6-31G basis set. The computational results diagnose the most stable conformer of formononetin. The HOMO-LUMO energy gap of possible conformers has been calculated for comparing their chemical activity. Chemical reactivity has been measured by reactivity descriptors and molecular electrostatic potential surface (MEP). The 1H and 13C NMR chemical shifts of the molecule were calculated by the Gauge including atomic orbital (GIAO) method. Furthermore, the role of CHsbnd O intramolecular hydrogen bond in the stability of molecule is investigated on the basis of the results of topological properties of AIM theory and NBO analysis. The calculated first hyperpolarizability shows that the molecule is an attractive molecule for future applications in non-linear optics.

Patient-related factors influence stiffness of the soft tissue complex during intraoperative gap balancing in cruciate-retaining total knee arthroplasty.

PubMed

Heesterbeek, P J C; Haffner, N; Wymenga, A B; Stifter, J; Ritschl, P

2017-09-01

How much force is needed to pre-tension the ligaments during total knee arthroplasty? The goal of this study was to determine this force for extension and flexion, and for both compartments, and to identify predicting patient-related factors. Eighty patients [55 females, mean age 71 (SD 9.7)] were recruited and had a navigated cruciate-retaining total knee arthroplasty. Distraction of the medial and lateral compartments of the extension and flexion gap (90°) with an instrumented bi-compartmental double-spring tensioner took place after finishing the bone cuts. Applied forces and resulting gap distances were recorded by the navigation system, resulting in a force-elongation curve. Lines were fitted with the intersection defined as the stiffness transition point. The slopes (N/mm) represented the stiffness of the ligamentous complex. Linear multiple regression analysis was performed to identify predicting factors. The amount of force at the stiffness transition point was on average 52.3 (CI 95 50.7-53.9), 54.5 (CI 95 52.7-56.3), 48.3 (CI 95 46.2-50.2), and 59.3 (CI 95 57.0-61.6) N for the medial and lateral extension and flexion gap, respectively, and varied considerably between patients. The force at the stiffness transition point was significantly different between extension and flexion and both compartments (P < 0.05). Stiffness of the ligaments statistically significantly helped to predict the amount of force at the stiffness transition point, as well as body mass index, gender, and varus-valgus alignment. The amount of force at the stiffness transition point varies between 48 and 59 N, depending on flexion/extension and compartment. Patient-related factors influence the stiffness transition point and can help predict the stiffness transition point. When forces higher than 60 N are used for gap distraction, the ligamentous sleeve of the knee might be over-tensioned. Prognostic study, Level I-high-quality prospective cohort study with >80 % follow-up, and all patients enrolled at same time point in disease.

Mixed formulation for seismic analysis of composite steel-concrete frame structures

NASA Astrophysics Data System (ADS)

Ayoub, Ashraf Salah Eldin

This study presents a new finite element model for the nonlinear analysis of structures made up of steel and concrete under monotonic and cyclic loads. The new formulation is based on a two-field mixed formulation. In the formulation, both forces and deformations are simultaneously approximated within the element through independent interpolation functions. The main advantages of the model is the accuracy in global and local response with very few elements while maintaining rapid numerical convergence and robustness even under severe cyclic loading. Overall four elements were developed based on the new formulation: an element that describes the behavior of anchored reinforcing bars, an element that describes the behavior of composite steel-concrete beams with deformable shear connectors, an element that describes the behavior of reinforced concrete beam-columns with bond-slip, and an element that describes the behavior of pretensioned or posttensioned, bonded or unbonded prestressed concrete structures. The models use fiber discretization of beam sections to describe nonlinear material response. The transfer of forces between steel and concrete is described with bond elements. Bond elements are modeled with distributed spring elements. The non-linear behavior of the composite element derives entirely from the constitutive laws of the steel, concrete and bond elements. Two additional elements are used for the prestressed concrete models, a friction element that models the effect of friction between the tendon and the duct during the posttensioning operation, and an anchorage element that describes the behavior of the prestressing tendon anchorage in posttensioned structures. Two algorithms for the numerical implementation of the new proposed model are presented; an algorithm that enforces stress continuity at element boundaries, and an algorithm in which stress continuity is relaxed locally inside the element. Stability of both algorithms is discussed. Comparison with standard displacement based models and earlier flexibility based models is presented through numerical studies. The studies prove the superiority of the mixed model over both displacement and flexibility models. Correlation studies of the proposed model with experimental results of structural specimens are conducted. The studies show the accuracy of the model and its numerical robustness even under severe cyclic loading conditions.

Biomechanics of 4-point seat belt systems in frontal impacts.

PubMed

Rouhana, Stephen W; Bedewi, Paul G; Kankanala, Sundeep V; Prasad, Priya; Zwolinski, Joseph J; Meduvsky, Alex G; Rupp, Jonathan D; Jeffreys, Thomas A; Schneider, Lawrence W

2003-01-01

The biomechanical behavior of 4-point seat belt systems was investigated through MADYMO modeling, dummy tests and post mortem human subject tests. This study was conducted to assess the effect of 4-point seat belts on the risk of thoracic injury in frontal impacts, to evaluate the ability to prevent submarining under the lap belt using 4-point seat belts, and to examine whether 4-point belts may induce injuries not typically observed with 3-point seat belts. The performance of two types of 4-point seat belts was compared with that of a pretensioned, load-limited, 3-point seat belt. A 3-point belt with an extra shoulder belt that "crisscrossed" the chest (X4) appeared to add constraint to the torso and increased chest deflection and injury risk. Harness style shoulder belts (V4) loaded the body in a different biomechanical manner than 3-point and X4 belts. The V4 belt appeared to shift load to the clavicles and pelvis and to reduce traction of the shoulder belt across the chest, resulting in a reduction in chest deflection by a factor of two. This is associated with a 5 to 500-fold reduction in thoracic injury risk, depending on whether one assumes 4-point belts apply concentrated or distributed load. In four of six post mortem human subjects restrained by V4 belts during 40 km/h sled tests, chest compression was zero or negative and rib fractures were nearly eliminated. Submarining was not observed in any test with post mortem human subjects. Though lumbar, sacral and pelvic injuries were noted, they are believed to be due to the artificial restraint environment (no knee bolsters, instrument panels, steering systems or airbags). While they show significant potential to reduce thoracic injury risk, there are still many issues to be resolved before 4-point belts can be considered for production vehicles. These issues include, among others, potential effects on hard and soft neck tissues, of interaction with inboard shoulder belts in farside impacts and potential effects on the fetus of latch/buckle junctions at the centerline of pregnant occupants. Work continues at Ford Motor Company to resolve these issues.

Predictors and Moderators of Spontaneous Pretend Play in Children with and without Autism Spectrum Disorder

PubMed Central

Kang, Erin; Klein, Eliana F.; Lillard, Angeline S.; Lerner, Matthew D.

2016-01-01

Although pretend play has long been linked to children’s normative cognitive development, inconsistent findings call for greater rigor in examining this relation (Lillard et al., 2013). Spontaneous pretend play is often impacted in atypical development, notably in autism spectrum disorder (ASD). Since ASD traits exist along a continuum in the general population, investigating how pretend play varies across the range of ASD symptoms by indexing variations in ASD traits in both typically developing and ASD populations may provide insight into how ASD symptoms may influence the relation between pretend play and associated processes in cognitive development. This study used rigorous observational methods to assess spontaneous pretend play. Specifically, 5-min free-play sessions with two discrete toy sets were double-coded by blinded coders (coder assignment counterbalanced). Key facets of pretense development [attribution of pretend properties (APP), object substitution (OS), imaginary objects] were examined. These facets of pretend play production were then analyzed in relation to ASD symptoms, as well as plausible, long-theorized correlates [theory of mind (ToM), verbal ability, familiarity, and interest in specific toys]. Forty children (Mage = 6;5, SDage = 1.45; 29 males), six of whom met the threshold for ASD diagnosis via parent-reported ASD symptoms, participated in play sessions and completed measures of verbal IQ and ToM. Besides the measure of child ASD symptoms, parents completed a survey of their child’s interest in and familiarity with the play session toys. Overall, greater ToM predicted more APP, and more interest in the toys presented predicted more OS. In terms of overall pretend play production, two results were counterintuitive. First, among children with more ASD symptoms, verbal ability marginally negatively predicted pretend play production. Second, among children with fewer ASD symptoms, ToM negatively predicted pretend play production. Further probing revealed that the negative effect of ASD symptoms on pretend play was simultaneously moderated by both variables: low ToM and high verbal ability both related to less pretend play production among children with more ASD symptoms. Implications for assessment and subsequent treatment for pretend ability among children with varying degrees of ASD symptoms, as well as for future research, are discussed. PMID:27790175

Do corresponding authors take responsibility for their work? A covert survey.

PubMed

Teunis, Teun; Nota, Sjoerd P F T; Schwab, Joseph H

2015-02-01

Publication of a manuscript does not end an author's responsibilities. Reasons to contact an author after publication include clarification, access to raw data, and collaboration. However, legitimate questions have been raised regarding whether these responsibilities generally are being met by corresponding authors of biomedical publications. This study aims to establish (1) what proportion of corresponding authors accept the responsibility of correspondence; (2) identify characteristics of responders; and (3) assess email address decay with time. We hypothesize that the response rate is unrelated to journal impact factor. We contacted 450 corresponding authors throughout various fields of biomedical research regarding the availability of additional data from their study, under the pretense of needing these data for a related review article. Authors were randomly selected from 45 journals whose impact factors ranged from 52 to 0; the source articles were published between May 2003 and May 2013. The proportion of corresponding authors who replied, along with author characteristics were recorded, as was the proportion of emails that were returned for inactive addresses; 446 authors were available for final analysis. Fifty-three percent (190/357) of the authors with working email addresses responded to our request. Clinical researchers were more likely to reply than basic/translational scientists (51% [114/225] versus 34% [76/221]; p<0.001). Impact factor and other author characteristics did not differ. Logistic regression analysis showed that the odds of replying decreased by 15% per year (odds ratio [OR], 0.85; 95% CI, 0.79-0.91; p<0.001), and showed a positive relationship between clinical research and response (OR, 2.0; 95% CI, 1.3-2.9; p=0.001). In 2013 all email addresses (45/45) were reachable, but within 10 years, 49% (21/43) had become invalid. Our results suggest that contacting corresponding authors is problematic throughout the field of biomedical research. Defining the responsibilities of corresponding authors by journals more explicitly-particularly after publication of their manuscript-may increase the response rate on data requests. Possible other ways to improve communication after research publication are: (1) listing more than one email address per corresponding author, eg, an institutional and personal address; (2) specifying all authors' email addresses; (3) when an author leaves an institution, send an automated reply offering alternative ways to get in touch; and (4) linking published manuscripts to research platforms.

Design and Experimental Verification of Deployable/Inflatable Ultra-Lightweight Structures

NASA Technical Reports Server (NTRS)

Pai, P. Frank

2004-01-01

Because launch cost of a space structural system is often proportional to the launch volume and mass and there is no significant gravity in space, NASA's space exploration programs and various science missions have stimulated extensive use of ultra-lightweight deployable/inflatable structures. These structures are named here as Highly Flexible Structures (HFSs) because they are designed to undergo large displacements, rotations, and/or buckling without plastic deformation under normal operation conditions. Except recent applications to space structural systems, HFSs have been used in many mechanical systems, civil structures, aerospace vehicles, home appliances, and medical devices to satisfy space limitations, provide special mechanisms, and/or reduce structural weight. The extensive use of HFSs in today's structural engineering reveals the need of a design and analysis software and a database system with design guidelines for practicing engineers to perform computer-aided design and rapid prototyping of HFSs. Also to prepare engineering students for future structural engineering requires a new and easy-to- understand method of presenting the complex mathematics of the modeling and analysis of HFSs. However, because of the high flexibility of HFSs, many unique challenging problems in the modeling, design and analysis of HFSs need to be studied. The current state of research on HFSs needs advances in the following areas: (1) modeling of large rotations using appropriate strain measures, (2) modeling of cross-section warpings of structures, (3) how to account for both large rotations and cross- section warpings in 2D (two-dimensional) and 1D structural theories, (4) modeling of thickness thinning of membranes due to inflation pressure, pretension, and temperature change, (5) prediction of inflated shapes and wrinkles of inflatable structures, (6) development of efficient numerical methods for nonlinear static and dynamic analyses, and (7) filling the gap between geometrically exact elastic analysis and elastoplastic analysis. The objectives of this research project were: (1) to study the modeling, design, and analysis of deployable/inflatable ultra-lightweight structures, (2) to perform numerical and experimental studies on the static and dynamic characteristics and deployability of HFSs, (3) to derive guidelines for designing HFSs, (4) to develop a MATLAB toolbox for the design, analysis, and dynamic animation of HFSs, and (5) to perform experiments and establish an adequate database of post-buckling characteristics of HFSs.

Coal Mine Roadway Stability in Soft Rock: A Case Study

NASA Astrophysics Data System (ADS)

Shen, Baotang

2014-11-01

Roadway instability has always been a major concern in deep underground coal mines where the surrounding rock strata and coal seams are weak and the in situ stresses are high. Under the high overburden and tectonic stresses, roadways could collapse or experience excessive deformation, which not only endangers mining personnel but could also reduce the functionality of the roadway and halt production. This paper describes a case study on the stability of roadways in an underground coal mine in Shanxi Province, China. The mine was using a longwall method to extract coal at a depth of approximately 350 m. Both the coal seam and surrounding rock strata were extremely weak and vulnerable to weathering. Large roadway deformation and severe roadway instabilities had been experienced in the past, hence, an investigation of the roadway failure mechanism and new support designs were needed. This study started with an in situ stress measurement programme to determine the stress orientation and magnitude in the mine. It was found that the major horizontal stress was more than twice the vertical stress in the East-West direction, perpendicular to the gateroads of the longwall panel. The high horizontal stresses and low strength of coal and surrounding rock strata were the main causes of roadway instabilities. Detailed numerical modeling was conducted to evaluate the roadway stability and deformation under different roof support scenarios. Based on the modeling results, a new roadway support design was proposed, which included an optimal cable/bolt arrangement, full length grouting, and high pre-tensioning of bolts and cables. It was expected the new design could reduce the roadway deformation by 50 %. A field experiment using the new support design was carried out by the mine in a 100 m long roadway section. Detailed extensometry and stress monitorings were conducted in the experimental roadway section as well as sections using the old support design. The experimental section produced a much better roadway profile than the previous roadway sections. The monitoring data indicated that the roadway deformation in the experimental section was at least 40-50 % less than the previous sections. This case study demonstrated that through careful investigation and optimal support design, roadway stability in soft rock conditions can be significantly improved.

Biomechanical cadaveric comparison of patellar ligament suture protected by a steel cable versus a synthetic cable.

PubMed

Bouget, P; Breque, C; Beranger, J S; Faure, J P; Khiami, F; Vendeuvre, T

2017-12-01

Purpose and hypothesis: Patellar ligament rupture is a rare disabling pathology requiring a surgical ligament suture protected by a frame. The gold standard is the steel cable, but its rigidity and the necessity of a surgical re-intervention for its removal render it unsatisfactory. The objective of this paper is to quantify the mechanical protection provided by the terylene® in comparison with steel. Twenty-four knees of 12 fresh frozen cadaveric subjects were divided into 2 homogeneous groups (terylene and steel) of 12 knees (mean age = 69.3 years). Proximal ligament repair was performed according to a three-tunnel transosseous reinsertion technique. Mechanical tests were performed in flexion to simulate movement of the knee. The interligament gap and the amplitude angulation of the knee were measured by a system of extensometer and optical goniometer. Mechanical analysis permitted calculation of flexion amplitude for a ligament gap of 1 and 2 mm taking as initial angle the adjusting angle of pretension of the protection frame. Study of deformations of frames was performed. Statistical analysis was performed with a Wilcoxon Mann Whitney test. There is no significant difference in protection of the ligament suture between the "terylene" and "steel" groups. Mean flexion amplitudes (mΔF) show no significant differences between the 2 groups for a distension of the suture of 1 mm (m ΔF terylene1 = 4.74 °; mΔF steel1 = 5.91°; p = 0.198) and 2 mm (mΔF terylene2 = 8.71°; mΔF steel2 = 10.41°; p = 0.114). Elastic deformation of terylene was significantly greater than that of steel (p = 0.0004). Suture protection of the patellar ligament by a terylene wire is not significantly different from that provided by steel frame. The elastic properties of terylene and absence of a need for re intervention to secure its removal lead us towards its use in acute ruptures of the patellar ligament. The main limits involve the properties of the chain extenders with no contraction/muscle shortening and partial dehydration of tendons and ligaments and the mean age of 69.3 years. Level 5.

Biomechanical characteristics of bioabsorbable magnesium-based (MgYREZr-alloy) interference screws with different threads.

PubMed

Ezechieli, Marco; Ettinger, Max; König, Carolin; Weizbauer, Andreas; Helmecke, Patrick; Schavan, Robert; Lucas, Arne; Windhagen, Henning; Becher, Christoph

2016-12-01

Degradable magnesium implants have received increasing interest in recent years. In anterior cruciate ligament reconstruction surgery, the well-known osteoconductive effects of biodegradable magnesium alloys may be useful. The aim of this study was to examine whether interference screws made of MgYREZr have comparable biomechanical properties to commonly used biodegradable screws and whether a different thread on the magnesium screw has an influence on the fixation strength. Five magnesium (MgYREZr-alloy) screws were tested per group. Three different groups with variable thread designs (Designs 1, 2, and 3) were produced and compared with the commercially available bioabsorbable Bioacryl rapid polylactic-co-glycolic acid screw Milagro ® . In vitro testing was performed in synthetic bone using artificial ligament fixed by an interference screw. The constructs were pretensioned with a constant load of 60 N for 30 s followed by 500 cycles between 60 N and 250 N at 1 Hz. Construct displacements between the 1st and 20th and the 21st and 500th cycles were recorded. After a 30 s break, a maximum load to failure test was performed at 1 mm/s measuring the maximum pull-out force. The maximum loads to failure of all three types of magnesium interference screws (Design 1: 1,092 ± 133.7 N; Design 2: 1,014 ± 103.3 N; Design 3: 1,001 ± 124 N) were significantly larger than that of the bioabsorbable Milagro ® interference screw (786.8 ± 62.5 N) (p < 0.05). However, the greatest maximum load was found with magnesium screw Design 1. Except for a significant difference between Designs 1 and 2, there were no further significant differences among the four groups in displacement after the 20th cycle. Biomechanical testing showed higher pull-out forces for magnesium compared with a commercial polymer screw. Hence, they suggest better stability and are a potential alternative. The thread geometry does not significantly influence the stability provided by the magnesium implants. This study shows the first promising results of a degradable material, which may be a clinical alternative in the future.

An analysis of the deployment of a pumpkin balloon on mars

NASA Astrophysics Data System (ADS)

Rand, J.; Phillips, M.

The design of large superpressure balloons has received significant attention in recent years due to the successful demonstration of various enabling technologies and materials. Of particular note is the "pumpkin" shaped balloon concept, which allows the stress in the envelope to be limited by the surface geometry. Unlike a sphere, which produces stress resultants determined by the volume of the system, the pumpkin utilizes a system of meridional tendons to react the loading in one direction, and form a number of lobes, which limit the stress in the circumferential direction. The application of this technology to very large systems is currently being demonstrated by NASA's Ultra Long Duration Balloon (ULDB) Program. However, this type of balloon has certain features that may be exploited to produce a system far more robust than a comparable sphere during deployment, inflation, and operation for long periods of time. When this concept is applied to a system designed to carry two kilograms in the atmosphere of Mars, the resulting balloon is small enough to alter the construction techniques and produce an envelope which is free of tucks and folds which may cause uncontrolled stress concentrations. A technique has been demonstrated where high strength tendons may be pretensioned prior to installation along the centerline of each gore. Since this position is the shortest distance between the apex and nadir of the balloon, the tendons will automatically resist the forces caused by deployment and inflation and thereby protect the thin film gas barrier from damage. A suitable balloon has been designed for this type of mission using five-micron Mylar Type C film for the gas barrier and P O braided cables for the meridionalB load carrying members. The deployment of this balloon is assumed to occur while falling on a decelerator suitably designed for the Mars atmosphere. The inflation is accomplished by a ten-kilogram system suspended at the nadir of the balloon. As the system falls toward the surface of the planet, helium gas is transferred to the balloon, forming a partially inflated system very similar to an ascending zero pressure balloon. This analysis incorporates the flow of the planetary gas around the inflating balloon, altering the pressure distribution and shape. As a result, stresses are seen to increase beyond the design margin of safety, requiring the balloon to be redesigned. In addition, several scale models of this balloon were dynamically deployed in the laboratory to demonstrate that the deployment forces are indeed carried by the tendons

Non-destructive testing for the structures and civil infrastructures characterization

NASA Astrophysics Data System (ADS)

Capozzoli, L.; Rizzo, E.

2012-04-01

This work evaluates the ability of non-conventional NDT techniques such as GPR, geoelectrical method and conventional ones such as infrared thermography (IRT) and sonic test for the characterization of building structures in laboratory and in-situ. Moreover, the integration of the different techniques were evaluated in order to reduce the degree of uncertainties associated. The presence of electromagnetic, resistivity or thermal anomalies in the behavior may be related to the presence of defects, crack, decay or moisture. The research was conducted in two phases: the first phase was performed in laboratory and the second one mainly in the field work. The laboratory experiments proceeded to calibrate the geophysical techniques GPR and geoelectrical method on building structures. A multi-layer structure was reconstructed in laboratory, in order to simulate a back-bridge: asphalt, reinforced concrete, sand and gravel layers. In the deep sandy layer, PVC, aluminum and steel pipes were introduced. This structure has also been brought to crack in a predetermined area and hidden internal fractures were investigated. GPR has allowed to characterize the panel in a non-invasive mode; radar maps were developed using various algorithms during post-process about 2D maps and 3D models with aerial acquisition of 400 MHz, 900MHz, 1500MHz, 2000MHz. Geoelectrical testing was performed with a network of 25 electrodes spaced at mutual distance of 5 cm. Two different configurations were used dipole-dipole and pole-dipole approaches. In the second phase, we proceeded to the analysis of pre-tensioned concrete in order to detect the possible presence of criticality in the structure. For this purpose by GPR 2GHz antenna, a '70 years precast bridge characterized by a high state of decay was studied; then were also analyzed a pillar and a beam of recent production directly into the processing plant. Moreover, results obtained using GPR were compared with those obtained through the use of infrared thermography and sonic testing. Finally, we investigated a radiant floor by GPR (900 MHz to 2000 MHz antennas) and long-wave infrared camera. Non-destructive diagnostic techniques allow to investigate a building structure in reinforced concrete or masonry without altering the characteristics of the element investigated. For this reason, geo-electrical and electromagnetic surveys of masonry are a suitable non-destructive tool for the diagnosis of a deteriorated concrete structure. Moreover, the integration of different NDT techniques (conventional and no-conventional) is a very powerful to maximize the capabilities and to compensate for the limitations of each method.

Evaluation of the First Transport Rotorcraft Airframe Crash Testbed (TRACT 1) Full-Scale Crash Test

NASA Technical Reports Server (NTRS)

Annett, Martin S.; Littell, Justin D.; Jackson, Karen E.; Bark, Lindley W.; DeWeese, Rick L.; McEntire, B. Joseph

2014-01-01

In 2012, the NASA Rotary Wing Crashworthiness Program initiated the Transport Rotorcraft Airframe Crash Testbed (TRACT) research program by obtaining two CH-46E helicopters from the Navy CH-46E Program Office (PMA-226) at the Navy Flight Readiness Center in Cherry Point, North Carolina. Full-scale crash tests were planned to assess dynamic responses of transport-category rotorcraft under combined horizontal and vertical impact loading. The first crash test (TRACT 1) was performed at NASA Langley Research Center's Landing and Impact Research Facility (LandIR), which enables the study of critical interactions between the airframe, seat, and occupant during a controlled crash environment. The CH-46E fuselage is categorized as a medium-lift rotorcraft with fuselage dimensions comparable to a regional jet or business jet. The first TRACT test (TRACT 1) was conducted in August 2013. The primary objectives for TRACT 1 were to: (1) assess improvements to occupant loads and displacement with the use of crashworthy features such as pre-tensioning active restraints and energy absorbing seats, (2) develop novel techniques for photogrammetric data acquisition to measure occupant and airframe kinematics, and (3) provide baseline data for future comparison with a retrofitted airframe configuration. Crash test conditions for TRACT 1 were 33-ft/s forward and 25-ft/s vertical combined velocity onto soft soil, which represent a severe, but potentially survivable impact scenario. The extraordinary value of the TRACT 1 test was reflected by the breadth of meaningful experiments. A total of 8 unique experiments were conducted to evaluate ATD responses, seat and restraint performance, cargo restraint effectiveness, patient litter behavior, and photogrammetric techniques. A combination of Hybrid II, Hybrid III, and ES-2 Anthropomorphic Test Devices (ATDs) were placed in forward and side facing seats and occupant results were compared against injury criteria. Loads from ATDs in energy absorbing seats and restraints were within injury limits. Severe injury was likely for ATDs in forward facing passenger seats, legacy troop bench seats, and a three-tiered patient litter. In addition, two standing ATDs were used to evaluate the benefit of Mobile Aircrew Restraint Systems (MARS) versus a standard gunner's belt. The ATD with the MARS survived the impact, while fatal head blunt trauma occurred for the standing ATD held by the legacy gunner's belt. In addition to occupant loading, the structural response of the airframe was assessed based on accelerometers located throughout the airframe and using three-dimensional photogrammetric techniques. Analysis of the photogrammetric data indicated regions of maximum deflection and permanent deformation.

Amateur observations of solar eclipses and derivation of scientific data

NASA Astrophysics Data System (ADS)

Stoev, A. D.; Stoeva, P. V.

2008-12-01

This work presents the educational approach of using total solar eclipse occurrences as a scientific process learning aid. The work reviews the basic scientific aims and experiments included in the observational programs "Total solar eclipse 1999 and 2006" (Stoev, A., Kiskinova, N., Muglova, P. et al. Complex observational programme of the Yuri Gagarin Public Astronomical Observatory and STIL, BAS, Stara Zagora Department for the August 11, 1999 total solar eclipse, in: Total Solar Eclipse 1999 - Observational Programmes and Coordination, Proceedings, Recol, Haskovo, pp. 133-137, 1999a (in Bulgarian); Stoeva, P.V., Stoev, A.D., Kostadinov, I.N. et al. Solar Corona and Atmospheric Effects during the March 29, 2006 Total Solar Eclipse, in: 11th International Science Conference SOLAR-Terrestrial Influences, Sofia, November 24-25, pp. 69-72, 2005). Results from teaching and training the students in the procedures, methods and equipment necessary for the observation of a total solar eclipse (TSE) at the Yuri Gagarin Public Astronomical Observatory (PAO) in Stara Zagora, Bulgaria, as well as the selection process used in determining participation in the different observational teams are discussed. The final stages reveal the special methodology used to investigate the level of "pretensions", the levels of ambition displayed by the students in achieving each independent goal, and the setting of goals in context with their problem solving capabilities and information gathering abilities in the scientific observation process. Results obtained from the observational experiments are interpreted mainly in the following themes: Investigation of the structure of the white-light solar corona and evolution of separate coronal elements during the total phase of the eclipse; Photometry of the white-light solar corona and specific emission lines; Meteorological, actinometrical and optical atmospheric investigations; Astrometry of the Moon during the phase evolution of the eclipse and Biological and behavioral reactions of highly organized colonies (ants and bats) during the eclipse. It is also shown that the students benefit from the activities of processing data, observational results and their interpretation, and preparation of summary reports. This exercise is intended to provide the basic training necessary to develop the creativity of the students and amateur astronomers involved. This will enable the students from the Astronomy schools at Public Astronomical Observatories and Planetaria (PAOP) to further develop their creative skills, emotional-volitional personal qualities with an orientation towards scientific analysis, using observations and experiments, to build an effective scientific style of thinking. Students of the Yuri Gagarin Public Astronomical Observatory, whom are already being nurtured in this manner, should be able to participate with great success in Scientific Research Programs devoted to the International Heliophysical Year.

Dynamic stabilization using the Dynesys system versus posterior lumbar interbody fusion for the treatment of degenerative lumbar spinal disease: a clinical and radiological outcomes-based meta-analysis.

PubMed

Lee, Chang-Hyun; Jahng, Tae-Ahn; Hyun, Seung-Jae; Kim, Chi Heon; Park, Sung-Bae; Kim, Ki-Jeong; Chung, Chun Kee; Kim, Hyun-Jib; Lee, Soo-Eon

2016-01-01

OBJECTIVE The Dynesys, a pedicle-based dynamic stabilization (PDS) system, was introduced to overcome the drawbacks of fusion procedures. Nevertheless, the theoretical advantages of PDS over fusion have not been clearly confirmed. The aim of this study was to compare clinical and radiological outcomes of patients who underwent PDS using the Dynesys system with those who underwent posterior lumbar interbody fusion (PLIF). METHODS The authors searched PubMed, Embase, Web of Science, and the Cochrane Database. Studies that reported outcomes of patients who underwent PDS or PLIF for the treatment of degenerative lumbar spinal disease were included. The primary efficacy end points were perioperative outcomes. The secondary efficacy end points were changes in the Oswestry Disability Index (ODI) and back and leg pain visual analog scale (VAS) scores and in range of motion (ROM) at the treated and adjacent segments. A meta-analysis was performed to calculate weighted mean differences (WMDs), 95% confidence intervals, Q statistics, and I(2) values. Forest plots were constructed for each analysis group. RESULTS Of the 274 retrieved articles, 7 (which involved 506 participants [Dynesys, 250; PLIF, 256]) met the inclusion criteria. The Dynesys group showed a competitive advantage in mean surgery duration (20.73 minutes, 95% CI 8.76-32.70 minutes), blood loss (81.87 ml, 95% CI 45.11-118.63 ml), and length of hospital stay (1.32 days, 95% CI 0.23-2.41 days). Both the Dynesys and PLIF groups experienced improved ODI and VAS scores after 2 years of follow-up. Regarding the ODI and VAS scores, no statistically significant difference was noted according to surgical procedure (ODI: WMD 0.12, 95% CI -3.48 to 3.72; back pain VAS score: WMD -0.15; 95% CI -0.56 to 0.26; leg pain VAS score: WMD -0.07; 95% CI -0.47 to 0.32). The mean ROM at the adjacent segment increased in both groups, and there was no substantial difference between them (WMD 1.13; 95% CI -0.33 to 2.59). Although the United States is the biggest market for Dynesys, no eligible study from the United States was found, and 4 of 8 enrolled studies were performed in China. The results must be interpreted with caution because of publication bias. During Dynesys implantation, surgeons have to decide the length of the spacer and cord pretension. These values are debatable and can vary according to the surgeon's experience and the patient's condition. Differences between the surgical procedures were not considered in this study. CONCLUSIONS Fusion still remains the method of choice for advanced degeneration and gross instability. However, spinal degenerative disease with or without Grade I spondylolisthesis, particularly in patients who require a quicker recovery, will likely constitute the main indication for PDS using the Dynesys system.

Comparison of Thoracic Injury Risk in Frontal Car Crashes for Occupant Restrained without Belt Load Limiters and Those Restrained with 6 kN and 4 kN Belt Load Limiters.

PubMed

Foret-Bruno, J Y; Trosseille, X; Page, Y; Huère, J F; Le Coz, J Y; Bendjellal, F; Diboine, A; Phalempin, T; Villeforceix, D; Baudrit, P; Guillemot, H; Coltat, J C

2001-11-01

In France, as in other countries, accident research studies show that a large proportion of restrained occupants who sustain severe or fatal injuries are involved in frontal impacts (65% and 50%, respectively). In severe frontal impacts with restrained occupants and where intrusion is not preponderant, the oldest occupants very often sustain severe thoracic injuries due to the conventional seat belt. As we have been observing over the last years, we will expect in the coming years developments which include more solidly-built cars, as offset crash test procedures are widely used to evaluate the passive safety of production vehicles. The reduction of intrusion for the most severe frontal impacts, through optimization of car deformation, usually translates into an increase in restraint forces and hence thoracic injury risk with a conventional retractor seat belt for a given impact severity. It is, therefore essential to limit the restraint forces exerted by the seat belt on the thorax in order to reduce the number of road casualties. In order to address thoracic injury risk in frontal impact, Renault cars have been equipped with the Programmed Restraint System (PRS) since 1995. The PRS is a restraint system that combines belt load limitation and pyrotechnic belt pretension. In an initial design of the Programmed Restraint System (PRS1), the belt load limiter was a steel component designed to shear at a given shoulder force, namely 6 kN. It was mounted between the retractor and the lower anchorage point of the belt. The design of the PRS was modified in 1998 (PRS2), but the principle of load limitation was maintained. The threshold was decreased to 4 kN and this lower belt belt-force limiter has been combined with a specially designed airbag. This paper reports on 347 real-world frontal accidents where the EES (Equivalent Energy Speed) ranged from 35 to 75 km/h. One hundred and ninety-eight (198) of these accidents involved cars equipped with the 6 kN load limiter, and 149 involved cars equipped with the 4 kN load limiter. Based on this accident data, the study compares the thoracic injury risk for two occupant populations: belted occupants involved in accidents in which the vehicle was not equipped with a load limiter (378 cases with pyrotechnic pretensioners), and belted occupants involved in accidents in which the vehicles were equipped with 4 or 6 kN load limiters and pyrotechnic pretensioners (347 cases). One observes that a 4 kN load limitation results in a very important reduction of thoracic injury risk for all AIS levels, compared to others samples. 50 to 60% reduction for AIS 2+ was observed, as well as 75 to 85% for AIS 3+. The complete absence of AIS 4+ with a 4 kN load limiter must be stressed, though it remains more than 8% for the other samples (no limiter and 6 kN limiter).

Mediarology

NASA Astrophysics Data System (ADS)

Schneider, S.

2006-12-01

Scientific assessments show a broad range of possible outcomes, but media coverage of the many aspects of the climate change debate often dichotomize into two camps: e.g. ignore the problem vs. stop it. This is exacerbated by an advocacy philosophy in which proponents take information out of context that supports their ideological positions and/or their clients' interests. Such courtroom epistemology feeds the media's pre- existing tendency to engage in balanced reporting: polarizing an issue despite a broad range of possible positions making each side equally credible, e.g., pitting a 200 author peer reviewed report against a lone PhD funded by special interests. This creates a false dichotomy: global warming is good for the Earth and too expensive to fix anyway, or it is the world's most serious problem, but relatively cheap to solve with renewable energy. I think these two are the lowest probability outliers as are: mitigating climate changes will bankrupt the US a frequent remark from some industries and the White House or technology will solve climate change at no cost, an overstatement by some deep green groups. Often neither side offers probabilities of outcomes or identifies the winners and losers from hypothesized climate impacts or policies to ameliorate them and when they do, it is rarely reported. To address the problem, scientists must take proactive roles in the public debate. We can help journalists by participating in the public climate change debate using clear metaphors and ordinary language without the pretense that we are above it since media is a time-constrained exercise and we insist all caveats must be reported. We must make it a priority to write review papers and present talks stressing well-established principles first, followed by cutting-edge science with its typical contention. Scientists, policy makers, the general citizenry, and journalists should enter the public debate, or the popularization of potential probabilities and consequences of climate change will occur without their input and will likely be more inaccurate, if not spun to ideological positions. It is impossible to obtain frequency data for events occurring in the future, so it is necessary to use subjective probabilities built on projections/models that compile all the relevant information we can bring to the problem, including, but not limited to, direct measurements and statistics. Scientists should provide subjective probabilistic assessments of climate change impacts for policy makers, with a special obligation to make any value judgments explicit. We must attempt to keep our value judgments out of the scientific assessment process, but if we choose to express a policy advocacy position as a citizen, it is imperative we make our personal values and prejudices explicit. A scientist-popularizer should publicly report community assessments and personal values clearly and explicitly. An effective scientist-popularizer must balance being heard good sound bites and simple metaphors with the responsibility to be honest all the caveats. Being both effective and honest is essential metaphors that convey both urgency and uncertainty work well, though it is a tough tradeoff when one has 20 seconds or 20 words to do it in! I believe a hierarchy of back up products op eds, Scientific American-type articles, and full length popular books to add all the nuances can help navigate sound-bite conundrums. Popularizers must answer 3 environmental literacy questions: What can happen? What are the odds of it happening? How are such estimates made? Plus non-scientists must attain a basic level of environmental, political, and scientific literacy so as to distinguish climate change science from spin and make critical value judgments and policy decisions.

Efficient flapping flight of pterosaurs

NASA Astrophysics Data System (ADS)

Strang, Karl Axel

In the late eighteenth century, humans discovered the first pterosaur fossil remains and have been fascinated by their existence ever since. Pterosaurs exploited their membrane wings in a sophisticated manner for flight control and propulsion, and were likely the most efficient and effective flyers ever to inhabit our planet. The flapping gait is a complex combination of motions that sustains and propels an animal in the air. Because pterosaurs were so large with wingspans up to eleven meters, if they could have sustained flapping flight, they would have had to achieve high propulsive efficiencies. Identifying the wing motions that contribute the most to propulsive efficiency is key to understanding pterosaur flight, and therefore to shedding light on flapping flight in general and the design of efficient ornithopters. This study is based on published results for a very well-preserved specimen of Coloborhynchus robustus, for which the joints are well-known and thoroughly described in the literature. Simplifying assumptions are made to estimate the characteristics that can not be inferred directly from the fossil remains. For a given animal, maximizing efficiency is equivalent to minimizing power at a given thrust and speed. We therefore aim at finding the flapping gait, that is the joint motions, that minimize the required flapping power. The power is computed from the aerodynamic forces created during a given wing motion. We develop an unsteady three-dimensional code based on the vortex-lattice method, which correlates well with published results for unsteady motions of rectangular wings. In the aerodynamic model, the rigid pterosaur wing is defined by the position of the bones. In the aeroelastic model, we add the flexibility of the bones and of the wing membrane. The nonlinear structural behavior of the membrane is reduced to a linear modal decomposition, assuming small deflections about the reference wing geometry. The reference wing geometry is computed for the membrane subject to glide loads and pretension from the wing joint positions. The flapping gait is optimized in a two-stage procedure. First the design space is explored using a binary genetic algorithm. The best design points are then used as starting points in a sequential quadratic programming optimization algorithm. This algorithm is used to refine the solutions by precisely satisfying the constraints. The refined solutions are found in generally less than twenty major iterations and constraints are violated generally by less than 0.1%. We find that the optimal motions are in agreement with previous results for simple wing motions. By adding joint motions, the required flapping power is reduced by 7% to 17%. Because of the large uncertainties for some estimates, we investigate the sensitivity of the optimized flapping gait. We find that the optimal motions are sensitive mainly to flight speed, body accelerations, and to the material properties of the wing membrane. The optimal flight speed found correlates well with other studies of pterosaur flapping flight, and is 31% to 37% faster than previous estimates based on glide performance. Accounting for the body accelerations yields an increase of 10% to 16% in required flapping power. When including the aeroelastic effects, the optimal flapping gait is only slightly modified to accommodate for the deflections of stiff membranes. For a flexible membrane, the motion is significantly modified and the power increased by up to 57%. Finally, the flapping gait and required power compare well with published results for similar wing motions. Some published estimates of required power assumed a propulsive efficiency of 100%, whereas the propulsive efficiency computed for Coloborhynchus robustus ranges between 54% and 87%.

Note on de Haas-van Alphen diamagnetism in thin, free-electron films

NASA Astrophysics Data System (ADS)

Grzesik, J. A.

2012-03-01

We revisit the problem of de Haas-van Alphen (dHvA) diamagnetic susceptibility oscillations in a thin, free-electron film trapped in a synthetic harmonic potential well. A treatment of this phenomenon at zero temperature was announced many years ago by Childers and Pincus (designated hereafter as CP), and we traverse initially much the same ground, but from a slightly different analytic perspective. That difference hinges around our use, in calculating the Helmholtz free energy F, of an inverse Laplace transform, Bromwich-type contour integral representation for the sharp distribution cutoff at Fermi level μ. The contour integral permits closed-form summation all at once over the discrete orbital Landau energy levels transverse to the magnetic field, and the energy associated with the in-plane canonical momenta ℏ k x and ℏ k z. Following such summation/integration, pole/residue pairs appear in the plane of complex transform variable s, a fourth-order pole at origin s = 0, and an infinite ladder, both up and down, of simple poles along the imaginary axis. The residue sum from the infinite pole ladder automatically engenders a Fourier series with period one in dimensionless variable μ/ ℏ ω (with effective angular frequency ω suitably defined), series which admits closed-form summation as a cubic polynomial within any given periodicity slot. Such periodicity corresponds to Landau levels slipping sequentially beneath Fermi level μ as the ambient magnetic field H declines in strength, and is manifested by the dHvA pulsations in diamagnetic susceptibility. The coëxisting steady contribution from the pole at origin has a similar cubic structure but is opposite in sign, inducing a competition whose outcome is a net magnetization that is merely quadratic in any given periodicity slot, modulated by a slow amplitude growth. Apart from some minor notes of passing discord, these simple algebraic structures confirm most of the CP formulae, and their graphic display reveals a numerically faithful portrait of the oscillatory dHvA diamagnetic susceptibility phenomenon. The calculations on view have a merely proof-of-principle aim, with no pretense at all of being exhaustive. The zero-temperature results hold moreover the key to the entire panorama of finite-temperature thermodynamics with T > 0. Indeed, thanks to the elegant work of Sondheimer and Wilson, one can promote the classical, Maxwell-Boltzmann partition function Z ( s ), via an inverse Laplace transform of its ratio to s 2, directly into the required, Fermi-Dirac Helmholtz free energy F at finite temperature T > 0. While the underlying cubic polynomial commonality continues to bestow decisive algebraic advantages, the evolving formulae are naturally more turgid than their zero-temperature counterparts. Nevertheless we do retain control over them by exhibiting their retrenchment into precisely these antecedents. So fortified, we undertake what is at once both a drastic and yet a simple-minded step of successive approximation, a step which clears the path toward numerical evaluation of the finite-temperature diamagnetic susceptibility. We are rewarded finally with a persistent dHvA periodicity imprint, but with its peaks increasingly flattened and its valleys filled in response to temperature rise, all as one would expect on physical grounds.

Intrinsically restless: Unifying science, writing, and the human condition

NASA Astrophysics Data System (ADS)

Sissom, Matthew

The field of physics has always fascinated me, but I never possessed the mathematical skills necessary to extend that interest past the point of curiosity. This thesis was set up to explore how I and other writers, specifically Walt Whitman, use(d) the skills we do have to ask and attempt to answer the same cosmic questions normally reserved for scientists overseeing particle collider experiments. In Tao of Physics, Fritjof Capra attempted to blend the principles of Eastern philosophy with the movements associated with modern physics. In doing so, he offers up a few insights into the human desire to "divide the world into separate objects and events" (117), which I believe, when it comes to fiction, greatly influences the audience's interpretive framework. Capra suggests, "To believe that our abstract concepts of separate `things' and `vents' are realities of nature is an illusion" (117). Humans use this division to cope with our everyday environment, yet it is not a fundamental feature of reality but, rather, an abstraction devised by our discriminating and categorizing intellect. It is a coping mechanism, as Capra refers to it, that pins writers in a corner, encouraging them to forms and styles set by their predecessors to better satisfy the "discriminating and categorizing intellect" of their audience. Writers often struggle to achieve a balance between accurately presenting the human condition that, like Capra's description of subatomic particles as "intrinsically restless" (117), changes based on myriad variables and properly structuring their writing to fit a predetermined model. Whitman, a fan of popular science, drew from the scientific world, using his understanding of the interpretive framework, to better craft his poems' metaphors. In "Song of Myself," Whitman suggests that the celebration of one's own existence cannot be separated from the celebration of the universe, "For every atom belonging to me as good belongs to you" (1-3). Whitman's writing reinforces the concept that the human desire to define existence begins at the subatomic level. In terms of my own writing, the focus turns to the origin of change. What is change? What brings it about? When I wrote "Of Higgs and Flame," the physics world was still riding the waves of CERN's Higgs boson particle discovery. Admittedly, the story contains a not-so-researched passage in which Darren contemplates the surge of change coursing from within, but this was done intentionally. Darren represents my approach to physics, which is mostly relegated to a spectator role, in that he is trying to define the occurring change based on his incomplete, loose understanding of Higgs boson and other scientific concepts. The analysis of my writing and that of Whitman reflects Stephen Hawking's explanation in A Briefer History of Time regarding the possibilities of a true, unifying theory of physics. He poses that there may exist an infinite sequence of theories that may get closer and closer to accurately describing the universe but are never exact (134). This is what I try to do with my work. I do not write under the pretense that I will be able to precisely replicate, in epiphany-like fashion, the human condition, accurately wrangling all of the variables that influence our reasons for changing or acting within a given scenario or conflict. Instead, I hope that my use of the same curiosity that fuels my passion to both read about physics and write fiction presents a more accurate understanding of the human condition, offering up characters whose changes within each story forces the audience to, at least momentarily, linger on that existential Why?.

Obituary: Dianne K. Prinz, 1938-2002

NASA Astrophysics Data System (ADS)

Cook, John William; Howard, Russell Alfred

2003-12-01

Dr. Dianne Kasnic Prinz died 12 October 2002 at the Hospice of Northern Virginia after a long struggle with lymphatic cancer. She worked for over 29 years until retirement at the Naval Research Laboratory in Washington, DC on sounding rocket, space shuttle, and satellite experiments to observe the Sun at ultraviolet wavelengths from space. Dianne Prinz was born 29 September 1938. She received her BS degree from the University of Pittsburgh in 1960, and a PhD in Physics from Johns Hopkins University in 1967, where she was a University Fellow 1960--1964 and a Gilman Fellow 1960--1963. She was a Research Associate in the Physics Department of the University of Maryland 1967--1971 and, from 1971 until her retirement in February 2001, she was a Research Physicist at the Naval Research Laboratory (NRL). At the time of her retirement she was Head of the Solar Radiation Section, Solar Physics Branch, Space Science Division of the Naval Research Laboratory and was supervising the work of a team of scientists that was operating the SUSIM (Solar Ultraviolet Irradiance Monitor) experiment on the UARS (Upper Atmosphere Research Satellite) spacecraft as well as reducing and analyzing the observations. Dianne was a member of the Washington Academy of Science (elected 1976 and Fellow 1987), served as Vice President of the National Capital Section of the Optical Society of America (1976), and received the Navy Award of Merit for Group Achievement (1985), the NASA Public Service Group Achievement Award (1987), and the Navy Meritorious Civilian Service Award (2001). Her professional memberships included the American Astronomical Society and its Solar Physics Division, the American Geophysical Union, and Sigma Xi. She had over 60 publications in her scientific bibliography. Early in her career at NRL, Dianne developed a Lyman alpha spectroheliograph sounding rocket payload. Launching at White Sands Missile Range in 1972, she obtained high spatial resolution (for that day) full disk solar images. Her published analysis was pioneering for the study of the Lyman alpha irradiance and established the range of brightness of solar active regions relative to the quiet disk. Dianne also had a keen interest in understanding how the upper atmosphere responds to changing solar conditions, a field of research now called ``space weather." Early in her career she collaborated with NRL scientists Robert Meier and Phillip Mange on the analysis of some of the first satellite remote sensing observations of the atmosphere and ionosphere. That work laid the foundation for many future NASA and DoD space weather programs, and throughout the years she continued to participate in the design of atmospheric remote sensing instruments that are flying in space today. In 1978 Dianne was selected by NASA to train as a Payload Specialist astronaut to operate the solar instruments that were to fly on the Spacelab 2 mission aboard the Space Shuttle. From a group of four in training (the others were Drs. J.D.-F. Bartoe, Loren Acton, and George Simon), Bartoe and Acton were finally selected and flew on the Spacelab 2 mission in 1985, when Dianne served as mission communicator with the Payload Specialists. She and Simon were due to fly on a planned follow-up second flight but the aftermath of the explosion of the Challenger Space Shuttle shortly afterward led to cancellation and the end of this phase of her career. In addition to the scientific aspects of her work, she made a substantial effort to communicate her enthusiasm to the public. After the Spacelab 2 mission she often gave presentations to adult and student audiences on her experiences, sometimes bringing along her flight suit. She received letters from all over the world from correspondents who had read of her role. Dianne was a member of the team at NRL that developed the requirements for a new instrument to accurately monitor, over many years, the solar ultraviolet irradiance, which was known to vary considerably and is a crucial input to many processes in the Earth's upper atmosphere. It was critical to overcome the challenge of maintaining the absolute calibration of an ultraviolet spectrometer. The new instrument, called the Solar Ultraviolet Spectral Irradiance Monitor (SUSIM), was flown first on an early Space Shuttle flight (STS-3) and next on the NASA Spacelab 2 mission, for which she had trained as an astronaut payload specialist. The SUSIM design was then revised for a long-term flight aboard the Upper Atmosphere Research Satellite (UARS). After the launch in 1991 of the UARS SUSIM, she led the NRL team that ran the UARS SUSIM flight operations and developed the data analysis software. After the death of Guenter Brueckner, she became the Principal Investigator of UARS SUSIM and continued the operation, analysis, and publication of these critical scientific observations. To determine the SUSIM absolute calibration, careful studies were performed to separate the degradation of the instrument response from the true solar variability. Extensive work was necessary to model the degradation of the instrumental sensitivity with time, the stray light correction, the field-of-view correction, and the wavelength scale. Dianne managed these tasks and produced a long term, well-calibrated history of solar ultraviolet irradiances over the full activity levels of a solar cycle. Dianne grew up on a farm in southwestern Pennsylvania, the daughter of Joseph J. Kasnic, a steel worker and part-time farmer, and Anna M. Kosyrich Kasnic, a homemaker, part-time teacher and accomplished artist and musician. Diane will be remembered for her deep love of animals, whether her beloved horse Chesterfield or stray or hungry cats in her neighborhood. Her marriage to Dr. Gary Prinz ended in divorce. She is survived by her sister and brother. Diane had an early interest in science and, throughout her career, worked as an experimental physicist and designer of optical instrumentation. She was a pioneer in her interests in space science, and usually overcame the obstacles she encountered in her field and at a time when she was often the first woman in authority encountered by male co-workers. She had a no-nonsense attitude in her work relations, but inspired the friendship of colleagues through her genuine good will, competence, and utter lack of pretension.