On adaptive robustness approach to Anti-Jam signal processing

NASA Astrophysics Data System (ADS)

Poberezhskiy, Y. S.; Poberezhskiy, G. Y.

An effective approach to exploiting statistical differences between desired and jamming signals named adaptive robustness is proposed and analyzed in this paper. It combines conventional Bayesian, adaptive, and robust approaches that are complementary to each other. This combining strengthens the advantages and mitigates the drawbacks of the conventional approaches. Adaptive robustness is equally applicable to both jammers and their victim systems. The capabilities required for realization of adaptive robustness in jammers and victim systems are determined. The employment of a specific nonlinear robust algorithm for anti-jam (AJ) processing is described and analyzed. Its effectiveness in practical situations has been proven analytically and confirmed by simulation. Since adaptive robustness can be used by both sides in electronic warfare, it is more advantageous for the fastest and most intelligent side. Many results obtained and discussed in this paper are also applicable to commercial applications such as communications in unregulated or poorly regulated frequency ranges and systems with cognitive capabilities.

Chaos Through-Wall Imaging Radar

NASA Astrophysics Data System (ADS)

Xu, Hang; Wang, Bingjie; Zhang, Jianguo; Liu, Li; Li, Ying; Wang, Yuncai; Wang, Anbang

2017-12-01

We experimentally demonstrate a chaos through-wall imaging radar using ultra-wideband chaotic-pulse-position modulation (CPPM) microwave signal. The CPPM signal based on logistic map with 1-ns pulse width and 1-GHz bandwidth is implemented by a field programmable gate array (FPGA) and then up-converted as the radar transmitting signal. Two-dimensional image of human objects behind obstacles is obtained by correlation method and back projection algorithm. Our experiments successfully perform through-wall imaging for single and multiple human objects through 20-cm thick wall. The down-range resolution of the proposed radar is 15 cm. Furthermore, the anti-jamming properties of the proposed radar in CPPM jamming, linear frequency-modulated jamming, and Gaussian noise jamming environments are demonstrated by electromagnetic simulations using the finite-difference time-domain. The simulation results show the CPPM microwave signal possesses excellent jamming immunity to the noise and radio frequency interference, which makes it perform superbly in multiradar environments.

Research on anti - interference based on GNSS

NASA Astrophysics Data System (ADS)

Yu, Huanran; Liu, Yijun

2017-05-01

Satellite Navigation System has been widely used in military and civil fields. It has all-functional, all-weather, continuity and real-time characteristics, can provide the precise position, velocity and timing information's for the users. The environments where the receiver of satellite navigation system works become more and more complex, and the satellite signals are susceptible to intentional or unintentional interferences, anti-jamming capability has become a key problem of satellite navigation receiver's ability to work normal. In this paper, we study a DOA estimation algorithm based on linear symmetric matrix to improve the anti-jamming capability of the satellite navigation receiver, has great significance to improve the performance of satellite navigation system in complex electromagnetic environment and enhance its applicability in various environments.

Altered expression of junctional adhesion molecule 4 in injured podocytes.

PubMed

Harita, Yutaka; Miyauchi, Naoko; Karasawa, Tamaki; Suzuki, Koichi; Han, Gi Dong; Koike, Hiroko; Igarashi, Takashi; Shimizu, Fujio; Kawachi, Hiroshi

2006-02-01

Recent investigations have revealed the importance of glomerular podocytes with its diaphragm as the major filtration barrier. Junctional adhesion molecule 4 (JAM4) has been identified as a protein that interacts with membrane-associated guanyl kinase inverted (MAGI)-1 and is reported to be expressed on podocytes. To elucidate the role of JAM4 on podocytes, we examined the expression of JAM4 and MAGI-1 in normal and two different proteinuric rat models: puromycin aminonucleoside (PAN) nephropathy and anti-nephrin antibody-induced (ANA) nephropathy, one model with and one without effacement of podocyte foot processes. JAM4 was detected by immunomicroscopy at the apical membrane of normal podocytes. JAM4 immunostaining was focally increased in the podocytes in PAN nephropathy but not in ANA nephropathy. In proteinuric podocytes, the expression of JAM4 was distinct from that of MAGI-1 or other slit diaphragm molecules such as nephrin and ZO-1. Close colocalization of JAM4 and ezrin was maintained in PAN nephropathy. By immunoelectron microscopy, the signals for JAM4 were detected at the free apical membrane of the podocytes with effaced foot processes. Studies with selective detergent extract revealed that the subcellular localization of JAM4 was altered in PAN nephropathy. Thus the altered expression of JAM4 appears to be associated with morphological changes in podocytes and can be a useful marker of injured podocytes. JAM4 may have a different role at the apical membrane besides the role as a junctional molecule and is likely associated with the unique structure of this epithelium.

Impact of jammer side information on the performance of anti-jam systems

NASA Astrophysics Data System (ADS)

Lim, Samuel

1992-03-01

The Chernoff bound parameter, D, provides a performance measure for all coded communication systems. D can be used to determine upper-bounds on bit error probabilities (BEPs) of Viterbi decoded convolutional codes. The impact on BEP bounds of channel measurements that provide additional side information can also be evaluated with D. This memo documents the results of a Chernoff bound parameter evaluation in optimum partial-band noise jamming (OPBNJ) for both BPSK and DPSK modulation schemes. Hard and soft quantized receivers, with and without jammer side information (JSI), were examined. The results of this analysis indicate that JSI does improve decoding performance. However, a knowledge of jammer presence alone achieves a performance level comparable to soft decision decoding with perfect JSI. Furthermore, performance degradation due to the lack of JSI can be compensated for by increasing the number of levels of quantization. Therefore, an anti-jam system without JSI can be made to perform almost as well as a system with JSI.

INTEGRATED INS/GPS NAVIGATION FROM A POPULAR PERSPECTIVE

DOT National Transportation Integrated Search

2002-02-13

Inertial navigation, blended with other navigation aids Global Positioning System (GPS) in particular, has gained significance due to enhanced navigation and inertial reference performance and dissimilarity for fault tolerance and anti-jamming. Relat...

High-Performance Anti-Retransmission Deception Jamming Utilizing Range Direction Multiple Input and Multiple Output (MIMO) Synthetic Aperture Radar (SAR).

PubMed

Wang, Ruijia; Chen, Jie; Wang, Xing; Sun, Bing

2017-01-09

Retransmission deception jamming seriously degrades the Synthetic Aperture Radar (SAR) detection efficiency and can mislead SAR image interpretation by forming false targets. In order to suppress retransmission deception jamming, this paper proposes a novel multiple input and multiple output (MIMO) SAR structure range direction MIMO SAR, whose multiple channel antennas are vertical to the azimuth. First, based on the multiple channels of range direction MIMO SAR, the orthogonal frequency division multiplexing (OFDM) linear frequency modulation (LFM) signal was adopted as the transmission signal of each channel, which is defined as a sub-band signal. This sub-band signal corresponds to the transmission channel. Then, all of the sub-band signals are modulated with random initial phases and concurrently transmitted. The signal form is more complex and difficult to intercept. Next, the echoes of the sub-band signal are utilized to synthesize a wide band signal after preprocessing. The proposed method will increase the signal to interference ratio and peak amplitude ratio of the signal to resist retransmission deception jamming. Finally, well-focused SAR imagery is obtained using a conventional imaging method where the retransmission deception jamming strength is degraded and defocused. Simulations demonstrated the effectiveness of the proposed method.

High-Performance Anti-Retransmission Deception Jamming Utilizing Range Direction Multiple Input and Multiple Output (MIMO) Synthetic Aperture Radar (SAR)

PubMed Central

Wang, Ruijia; Chen, Jie; Wang, Xing; Sun, Bing

2017-01-01

Retransmission deception jamming seriously degrades the Synthetic Aperture Radar (SAR) detection efficiency and can mislead SAR image interpretation by forming false targets. In order to suppress retransmission deception jamming, this paper proposes a novel multiple input and multiple output (MIMO) SAR structure range direction MIMO SAR, whose multiple channel antennas are vertical to the azimuth. First, based on the multiple channels of range direction MIMO SAR, the orthogonal frequency division multiplexing (OFDM) linear frequency modulation (LFM) signal was adopted as the transmission signal of each channel, which is defined as a sub-band signal. This sub-band signal corresponds to the transmission channel. Then, all of the sub-band signals are modulated with random initial phases and concurrently transmitted. The signal form is more complex and difficult to intercept. Next, the echoes of the sub-band signal are utilized to synthesize a wide band signal after preprocessing. The proposed method will increase the signal to interference ratio and peak amplitude ratio of the signal to resist retransmission deception jamming. Finally, well-focused SAR imagery is obtained using a conventional imaging method where the retransmission deception jamming strength is degraded and defocused. Simulations demonstrated the effectiveness of the proposed method. PMID:28075367

Hawkmoths produce anti-bat ultrasound

PubMed Central

Barber, Jesse R.; Kawahara, Akito Y.

2013-01-01

Bats and moths have been engaged in aerial warfare for nearly 65 Myr. This arms race has produced a suite of counter-adaptations in moths, including bat-detecting ears. One set of defensive strategies involves the active production of sound; tiger moths' ultrasonic replies to bat attack have been shown to startle bats, warn the predators of bad taste and jam their biosonar. Here, we report that hawkmoths in the Choerocampina produce entirely ultrasonic sounds in response to tactile stimulation and the playback of biosonar attack sequences. Males do so by grating modified scraper scales on the outer surface of the genital valves against the inner margin of the last abdominal tergum. Preliminary data indicate that females also produce ultrasound to touch and playback of echolocation attack, but they do so with an entirely different mechanism. The anti-bat function of these sounds is unknown but might include startling, cross-family acoustic mimicry, warning of unprofitability or physical defence and/or jamming of echolocation. Hawkmoths present a novel and tractable system to study both the function and evolution of anti-bat defences. PMID:23825084

Blocking Junctional Adhesion Molecule C Enhances Dendritic Cell Migration and Boosts the Immune Responses against Leishmania major

PubMed Central

Ballet, Romain; Emre, Yalin; Jemelin, Stéphane; Charmoy, Mélanie; Tacchini-Cottier, Fabienne; Imhof, Beat A.

2014-01-01

The recruitment of dendritic cells to sites of infections and their migration to lymph nodes is fundamental for antigen processing and presentation to T cells. In the present study, we showed that antibody blockade of junctional adhesion molecule C (JAM-C) on endothelial cells removed JAM-C away from junctions and increased vascular permeability after L. major infection. This has multiple consequences on the output of the immune response. In resistant C57BL/6 and susceptible BALB/c mice, we found higher numbers of innate immune cells migrating from blood to the site of infection. The subsequent migration of dendritic cells (DCs) from the skin to the draining lymph node was also improved, thereby boosting the induction of the adaptive immune response. In C57BL/6 mice, JAM-C blockade after L. major injection led to an enhanced IFN-γ dominated T helper 1 (Th1) response with reduced skin lesions and parasite burden. Conversely, anti JAM-C treatment increased the IL-4-driven T helper 2 (Th2) response in BALB/c mice with disease exacerbation. Overall, our results show that JAM-C blockade can finely-tune the innate cell migration and accelerate the consequent immune response to L. major without changing the type of the T helper cell response. PMID:25474593

[A wireless mobile monitoring system based on bluetooth technology].

PubMed

Sun, Shou-jun; Wu, Kai; Wu, Xiao-Ming

2006-09-01

This paper presents a wireless mobile monitoring system based on Bluetooth technology. This system realizes the remote mobile monitoring of multiple physiological parameters, and has the characters of easy use, low cost, good reliability and strong capability of anti-jamming.

Preparation of anti-Sudan red monoclonal antibody and development of an indirect competitive enzyme-linked immunosorbent assay for detection of Sudan red in chilli jam and chilli oil.

PubMed

Xu, Jing; Zhang, Yuanyang; Yi, Jian; Meng, Meng; Wan, Yuping; Feng, Caiwei; Wang, Shanliang; Lu, Xiao; Xi, Rimo

2010-10-01

Sudan dyes are banned to be used in food additives because of the carcinogenicity of their metabolites. A rapid and sensitive indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed to detect the residues of Sudan dyes. Novel immunogen and coating antigen were synthesized via glutaraldehyde linking. The hapten-bovine serum albumin (BSA) was applied as immunogen and the hapten-ovalbumin (OVA) was served as coating antigen. The monoclonal antibody obtained showed high sensitivity to Sudan I with an IC(50) value of 1.7 μg L(-1) in buffer and was suitable to detect the residues of Sudan red in food products. The specificity of the assay was studied by measuring cross-reactivity of the antibody with the structurally related compounds of Sudan II (<1%), Sudan IV (<1%) and para red (120%). Chilli jam and chilli oil samples spiked with Sudan dyes were analyzed by the method. The detection limit (LOD) of the ELISA method applied in chilli jam and chilli oil was 9.0 μg L(-1) and 19.6 μg L(-1), respectively. The recovery rates of Sudan-I in chilli oil and chilli jam were in the range of 80%-110% with coefficients of variation <25%. The intra-assay variation and inter-assay variation in buffer were both <9%.

Research on the frequency hopping bistatic sonar system

NASA Astrophysics Data System (ADS)

Liang, Guo-long; Zhang, Yao; Zhang, Guang-pu; Liu, Kai

2011-10-01

A new model for bistatic sonar system is established, in which frequency hopping (FH) signals are used for targets detection according to some rules. This model can decrease the time between adjacent signals and obtain more information in a unit time. The receiving system will receive and process the signals of different frequency respectively, according the FH pattern, for detecting and locating targets. This method can helps yield more stable and accurate outputs, using the characteristic of the FH signals, increase the ability of anti-detection and anti partial-band jamming.

Assessment of Brazil’s Research Literature

DTIC Science & Technology

2007-09-28

Autonomously interconnecting with real-time monitoring • Secure, survivable, self - healing , and adaptable • Resistant to jamming • Homeland and... self - healing platforms • Force Protection • Anti-swimmer technology • Detect and determine threat intent • Non-lethal response Associated CV...Brazilian strengths in chemistry and several industrially oriented R&D domains. We apply text clustering to obtain “ self -organizing tables of

Design and Processing of a Novel Chaos-Based Stepped Frequency Synthesized Wideband Radar Signal.

PubMed

Zeng, Tao; Chang, Shaoqiang; Fan, Huayu; Liu, Quanhua

2018-03-26

The linear stepped frequency and linear frequency shift keying (FSK) signal has been widely used in radar systems. However, such linear modulation signals suffer from the range-Doppler coupling that degrades radar multi-target resolution. Moreover, the fixed frequency-hopping or frequency-coded sequence can be easily predicted by the interception receiver in the electronic countermeasures (ECM) environments, which limits radar anti-jamming performance. In addition, the single FSK modulation reduces the radar low probability of intercept (LPI) performance, for it cannot achieve a large time-bandwidth product. To solve such problems, we propose a novel chaos-based stepped frequency (CSF) synthesized wideband signal in this paper. The signal introduces chaotic frequency hopping between the coherent stepped frequency pulses, and adopts a chaotic frequency shift keying (CFSK) and phase shift keying (PSK) composited coded modulation in a subpulse, called CSF-CFSK/PSK. Correspondingly, the processing method for the signal has been proposed. According to our theoretical analyses and the simulations, the proposed signal and processing method achieve better multi-target resolution and LPI performance. Furthermore, flexible modulation is able to increase the robustness against identification of the interception receiver and improve the anti-jamming performance of the radar.

Two bHLH-type transcription factors, JA-ASSOCIATED MYC2-LIKE2 and JAM3, are transcriptional repressors and affect male fertility

PubMed Central

Nakata, Masaru; Ohme-Takagi, Masaru

2013-01-01

The jasmonate (JA) plant hormones regulate responses to biotic and abiotic stress and aspects of plant development, including male fertility in Arabidopsis thaliana. The bHLH-type transcription factor JA-ASSOCIATED MYC2-LIKE1 (JAM1) negatively regulates JA signaling and gain-of-function JAM1 transgenic plants have impaired JA-mediated male fertility. Here we report that JAM2 and JAM3, 2 bHLHs closely related to JAM1, also act as transcriptional repressors. Moreover, overexpression of JAM2 and JAM3 also results in reduced male fertility. These results suggest that JAM1, JAM2, and JAM3 act redundantly as negative regulators of JA-mediated male fertility. PMID:24056034

Very Large Scale Integrated Circuits for Military Systems.

DTIC Science & Technology

1981-01-01

ABBREVIATIONS A/D Analog-to-digital C AGC Automatic Gain Control A A/J Anti-jam ASP Advanced Signal Processor AU Arithmetic Units C.AD Computer-Aided...ESM) equipments (Ref. 23); in lieu of an adequate automatic proces- sing capability, the function is now performed manually (Ref. 24), which involves...a human operator, displays, etc., and a sacrifice in performance (acquisition speed, saturation signal density). Various automatic processing

GPS & Galileo. Friendly Foes?

DTIC Science & Technology

2007-04-01

some of their data, others employ different techniques. United States defense contractor Lockheed Martin developed an anti-jam GPS receiver in 2000 for...Europe in a New Generation of Satellite Navigation Services,” European Commission (9 Feb 1999): 16. 25. Ibid. 26. Anne Jolis , “Problems Run Rampant...European Outer Space,” Euro Topics (19 March 2007), found at http://www.eurotopics.net/en/presseschau/archiv/archiv_dossier/DOSSIER15435. 40. Jolis

Director, Operational Test and Evaluation FY 2004 Annual Report

DTIC Science & Technology

2004-01-01

HIGH) Space Based Radar (SBR) Sensor Fuzed Weapon (SFW) P3I (CBU-97/B) Small Diameter Bomb (SDB) Secure Mobile Anti-Jam Reliable Tactical Terminal...detection, identification, and sampling capability for both fixed-site and mobile operations. The system must automatically detect and identify up to ten...staffing within the Services. SYSTEM DESCRIPTION AND MISSION The Services envision JCAD as a hand-held device that automatically detects, identifies, and

Experiment on a three-beam adaptive array for EHF frequency-hopped signals using a fast algorithm, phase-D

NASA Astrophysics Data System (ADS)

Yen, J. L.; Kremer, P.; Amin, N.; Fung, J.

1989-05-01

The Department of National Defence (Canada) has been conducting studies into multi-beam adaptive arrays for extremely high frequency (EHF) frequency hopped signals. A three-beam 43 GHz adaptive antenna and a beam control processor is under development. An interactive software package for the operation of the array, capable of applying different control algorithms is being written. A maximum signal to jammer plus noise ratio (SJNR) was found to provide superior performance in preventing degradation of user signals in the presence of nearby jammers. A new fast algorithm using a modified conjugate gradient approach was found to be a very efficient way to implement anti-jamming arrays based on maximum SJNR criterion. The present study was intended to refine and simplify this algorithm and to implement the algorithm on an experimental array for real-time evaluation of anti-jamming performance. A three-beam adaptive array was used. A simulation package was used in the evaluation of multi-beam systems using more than three beams and different user-jammer scenarios. An attempt to further reduce the computation burden through continued analysis of maximum SJNR met with limited success. A method to acquire and track an incoming laser beam is proposed.

Experiment on a three-beam adaptive array for EHF frequency-hopped signals using a fast algorithm, phase E

NASA Astrophysics Data System (ADS)

Yen, J. L.; Kremer, P.; Fung, J.

1990-05-01

The Department of National Defence (Canada) has been conducting studies into multi-beam adaptive arrays for extremely high frequency (EHF) frequency hopped signals. A three-beam 43 GHz adaptive antenna and a beam control processor is under development. An interactive software package for the operation of the array, capable of applying different control algorithms is being written. A maximum signal to jammer plus noise ratio (SJNR) has been found to provide superior performance in preventing degradation of user signals in the presence of nearby jammers. A new fast algorithm using a modified conjugate gradient approach has been found to be a very efficient way to implement anti-jamming arrays based on maximum SJNR criterion. The present study was intended to refine and simplify this algorithm and to implement the algorithm on an experimental array for real-time evaluation of anti-jamming performance. A three-beam adaptive array was used. A simulation package was used in the evaluation of multi-beam systems using more than three beams and different user-jammer scenarios. An attempt to further reduce the computation burden through further analysis of maximum SJNR met with limited success. The investigation of a new angle detector for spatial tracking in heterodyne laser space communications was completed.

LETTER TO THE EDITOR: Backbones of traffic jams

NASA Astrophysics Data System (ADS)

Shikhar Gupta, Himadri; Ramaswamy, Ramakrishna

1996-11-01

We study the jam phase of the deterministic traffic model in two dimensions. Within the jam phase, there is a phase transition, from a self-organized jam (formed by initial synchronization followed by jamming), to a random-jam structure. The backbone of the jam is defined and used to analyse self-organization in the jam. The fractal dimension and interparticle correlations on the backbone indicate a continous phase transition at density 0305-4470/29/21/003/img1 with critical exponent 0305-4470/29/21/003/img2, which are characterized through simulations.

Schwann cell-specific JAM-C-deficient mice reveal novel expression and functions for JAM-C in peripheral nerves.

PubMed

Colom, Bartomeu; Poitelon, Yannick; Huang, Wenlong; Woodfin, Abigail; Averill, Sharon; Del Carro, Ubaldo; Zambroni, Desirée; Brain, Susan D; Perretti, Mauro; Ahluwalia, Amrita; Priestley, John V; Chavakis, Triantafyllos; Imhof, Beat A; Feltri, M Laura; Nourshargh, Sussan

2012-03-01

Junctional adhesion molecule-C (JAM-C) is an adhesion molecule expressed at junctions between adjacent endothelial and epithelial cells and implicated in multiple inflammatory and vascular responses. In addition, we recently reported on the expression of JAM-C in Schwann cells (SCs) and its importance for the integrity and function of peripheral nerves. To investigate the role of JAM-C in neuronal functions further, mice with a specific deletion of JAM-C in SCs (JAM-C SC KO) were generated. Compared to wild-type (WT) controls, JAM-C SC KO mice showed electrophysiological defects, muscular weakness, and hypersensitivity to mechanical stimuli. In addressing the underlying cause of these defects, nerves from JAM-C SC KO mice were found to have morphological defects in the paranodal region, exhibiting increased nodal length as compared to WTs. The study also reports on previously undetected expressions of JAM-C, namely on perineural cells, and in line with nociception defects of the JAM-C SC KO animals, on finely myelinated sensory nerve fibers. Collectively, the generation and characterization of JAM-C SC KO mice has provided unequivocal evidence for the involvement of SC JAM-C in the fine organization of peripheral nerves and in modulating multiple neuronal responses.

Aspects of jamming in two-dimensional athermal frictionless systems.

PubMed

Reichhardt, C; Reichhardt, C J Olson

2014-05-07

In this work we provide an overview of jamming transitions in two dimensional systems focusing on the limit of frictionless particle interactions in the absence of thermal fluctuations. We first discuss jamming in systems with short range repulsive interactions, where the onset of jamming occurs at a critical packing density and where certain quantities show a divergence indicative of critical behavior. We describe how aspects of the dynamics change as the jamming density is approached and how these dynamics can be explored using externally driven probes. Different particle shapes can produce jamming densities much lower than those observed for disk-shaped particles, and we show how jamming exhibits fragility for some shapes while for other shapes this is absent. Next we describe the effects of long range interactions and jamming behavior in systems such as charged colloids, vortices in type-II superconductors, and dislocations. We consider the effect of adding obstacles to frictionless jamming systems and discuss connections between this type of jamming and systems that exhibit depinning transitions. Finally, we discuss open questions such as whether the jamming transition in all these different systems can be described by the same or a small subset of universal behaviors, as well as future directions for studies of jamming transitions in two dimensional systems, such as jamming in self-driven or active matter systems.

Jamming in Disordered and Ordered States: From RLP to FCC

NASA Astrophysics Data System (ADS)

Silbert, Leonardo

2011-03-01

The concept of jamming was originally introduced in the context of zero-temperature, frictionless sphere packings through which the jamming transition was identified with the more familiar idea of random close packing. More recently, the jamming behaviour for particles with friction has led to a practical definition of the less well-defined random loose packed limit. However, there are a number of subtleties associated with jamming that extend these concepts further. Here we implement a range of protocols to generate jammed packings both with and without friction, and find that the jamming transition actually consists of a finite region in packing fraction depending on the protocol used to create the jammed state. Furthermore, we examine how it is possible to tune the structural properties of jammed packings from the disordered regime through to the ordered face centred cubic lattice, and the subsequent changes in the jamming properties as the structure is manipulated. Supported by NSF CBET-0828359.

Cruise Missile Penaid Nonproliferation: Hindering the Spread of Countermeasures Against Cruise Missile Defenses

DTIC Science & Technology

2014-01-01

this report treats cruise missile penaids and UAV penaids, sometimes called “self-protection” (see La Franchi , 2004), interchangeably. 8 Cruise...Penaid Export Controls 41 2. Anti-Jam Equipment MTCR Item 11.A.3.b.3 (Avionics): Current text: “Receiving equipment for Global Navigation Satellite...subsystems beyond those for global navigation satellite systems to all sensor, navigation, and communications systems, and add “including multi-mode

Detecting and Jamming Dynamic Communication Networks in Anti-Access Environments

DTIC Science & Technology

2011-03-01

P.M. Pardalos, Y. Ye. and C.W. Commander (eds) V. Boginski. Sensors: Theory , Algorithms, and Applications. Springer, to appear in 2009. [21] Joseph C...Sumeetpal S. Singh. Nikolaos Kantas , Ba-Ngu Vo, Arnaud Doucet, and Robin J. Evans. Simulation-based optimal sensor scheduling with application to...observer trajectory planning. Aotomatica, 43(5):817-830, 2007. [27] Anthony Man-Cho So and Yinyu Ye. Theory of semidefinite programming for sensor network

Schwann cell-specific JAM-C-deficient mice reveal novel expression and functions for JAM-C in peripheral nerves

PubMed Central

Colom, Bartomeu; Poitelon, Yannick; Huang, Wenlong; Woodfin, Abigail; Averill, Sharon; Del Carro, Ubaldo; Zambroni, Desirée; Brain, Susan D.; Perretti, Mauro; Ahluwalia, Amrita; Priestley, John V.; Chavakis, Triantafyllos; Imhof, Beat A.; Feltri, M. Laura; Nourshargh, Sussan

2012-01-01

Junctional adhesion molecule-C (JAM-C) is an adhesion molecule expressed at junctions between adjacent endothelial and epithelial cells and implicated in multiple inflammatory and vascular responses. In addition, we recently reported on the expression of JAM-C in Schwann cells (SCs) and its importance for the integrity and function of peripheral nerves. To investigate the role of JAM-C in neuronal functions further, mice with a specific deletion of JAM-C in SCs (JAM-C SC KO) were generated. Compared to wild-type (WT) controls, JAM-C SC KO mice showed electrophysiological defects, muscular weakness, and hypersensitivity to mechanical stimuli. In addressing the underlying cause of these defects, nerves from JAM-C SC KO mice were found to have morphological defects in the paranodal region, exhibiting increased nodal length as compared to WTs. The study also reports on previously undetected expressions of JAM-C, namely on perineural cells, and in line with nociception defects of the JAM-C SC KO animals, on finely myelinated sensory nerve fibers. Collectively, the generation and characterization of JAM-C SC KO mice has provided unequivocal evidence for the involvement of SC JAM-C in the fine organization of peripheral nerves and in modulating multiple neuronal responses.—Colom, B., Poitelon, Y., Huang, W., Woodfin, A., Averill, S., Del Carro, U., Zambroni, D., Brain, S. D., Perretti, M., Ahluwalia, A., Priestley, J. V., Chavakis, T., Imhof, B. A., Feltri, M. L., Nourshargh, S. Schwann cell-specific JAM-C-deficient mice reveal novel expression and functions for JAM-C in peripheral nerves. PMID:22090315

Junctional Adhesion Molecule (JAM)-C Deficient C57BL/6 Mice Develop a Severe Hydrocephalus

PubMed Central

Liebner, Stefan; Mittelbronn, Michel; Deutsch, Urban; Enzmann, Gaby; Adams, Ralf H.; Aurrand-Lions, Michel; Plate, Karl H.; Imhof, Beat A.; Engelhardt, Britta

2012-01-01

The junctional adhesion molecule (JAM)-C is a widely expressed adhesion molecule regulating cell adhesion, cell polarity and inflammation. JAM-C expression and function in the central nervous system (CNS) has been poorly characterized to date. Here we show that JAM-C−/− mice backcrossed onto the C57BL/6 genetic background developed a severe hydrocephalus. An in depth immunohistochemical study revealed specific immunostaining for JAM-C in vascular endothelial cells in the CNS parenchyma, the meninges and in the choroid plexus of healthy C57BL/6 mice. Additional JAM-C immunostaining was detected on ependymal cells lining the ventricles and on choroid plexus epithelial cells. Despite the presence of hemorrhages in the brains of JAM-C−/− mice, our study demonstrates that development of the hydrocephalus was not due to a vascular function of JAM-C as endothelial re-expression of JAM-C failed to rescue the hydrocephalus phenotype of JAM-C−/− C57BL/6 mice. Evaluation of cerebrospinal fluid (CSF) circulation within the ventricular system of JAM-C−/− mice excluded occlusion of the cerebral aqueduct as the cause of hydrocephalus development but showed the acquisition of a block or reduction of CSF drainage from the lateral to the 3rd ventricle in JAM-C−/− C57BL/6 mice. Taken together, our study suggests that JAM-C−/− C57BL/6 mice model the important role for JAM-C in brain development and CSF homeostasis as recently observed in humans with a loss-of-function mutation in JAM-C. PMID:23029139

Optimisation of microwave-assisted processing in production of pineapple jam

NASA Astrophysics Data System (ADS)

Ismail, Nur Aisyah Mohd; Abdullah, Norazlin; Muhammad, Norhayati

2017-10-01

Pineapples are available all year round since they are unseasonal fruits. Due to the continuous harvesting of the fruit, the retailers and farmers had to find a solution such as the processing of pineapple into jam, to treat the unsuccessfully sold pineapples. The direct heating of pineapple puree during the production of pineapple jam can cause over degradation of quality of the fresh pineapple. Thus, this study aims to optimise the microwave-assisted processing conditions for producing pineapple jam which could reduce water activity and meets minimum requirement for pH and total soluble solids contents of fruit jam. The power and time of the microwave processing were chosen as the factors, while the water activity, pH and total soluble solids (TSS) content of the pineapple jam were determined as responses to be optimised. The microwave treatment on the pineapple jam was able to give significant effect on the water activity and TSS content of the pineapple jam. The optimum power and time for the microwave processing of pineapple jam is 800 Watt and 8 minutes, respectively. The use of domestic microwave oven for the pineapple jam production results in acceptable pineapple jam same as conventional fruit jam sold in the marketplace.

A novel junctional adhesion molecule A (CgJAM-A-L) from oyster (Crassostrea gigas) functions as pattern recognition receptor and opsonin.

PubMed

Liu, Conghui; Wang, Mengqiang; Jiang, Shuai; Wang, Lingling; Chen, Hao; Liu, Zhaoqun; Qiu, Limei; Song, Linsheng

2016-02-01

Junctional adhesion molecule (JAM), a subfamily of immunoglobulin superfamily (IgSF) with a couple of immunoglobulin domains, can act as regulator in homeostasis and inflammation of vertebrates. In the present study, a structural homolog of JAM-A (designated CgJAM-A-L) was screened out from oyster, Crassostrea gigas, through a search of JAM-A D1 domain (N-terminal Ig domain in JAM-A). The cDNA of CgJAM-A-L was of 1188 bp encoding a predicted polypeptide of 395 amino acids. The immunoreactive area of CgJAM-A-L mainly distributed over the plasma membrane of hemocytes. After Vibro splendidus or tumor necrosis factor (CgTNF-1) stimulation, the mRNA transcripts of CgJAM-A-L in hemocytes increased significantly by 4.46-fold and 9.00-fold (p < 0.01) of those in control group, respectively. The recombinant CgJAM-A-L protein (rCgJAM-A-L) could bind multiple PAMPs including lipopolysaccharides (LPS), peptidoglycan (PGN), lipoteichoic acid (LTA), mannose (MAN), β-glucan (GLU) and poly(I:C), and various microorganisms including Micrococcus luteus, Staphylococcus aureus, Escherichia coli, Vibro anguillarum, V. splendidus, Pastoris pastoris and Yarrowia lipolytica. The phagocytic rates of oyster hemocytes towards Gram-negative bacteria V. anguillarum and yeast P. pastoris were significantly enhanced after the incubation of rCgJAM-A-L, and even increased more significantly after the pre-incubation of rCgJAM-A-L with microbes (p < 0.01). The results collectively indicated that CgJAM-A-L functioned as an important pattern recognition receptor (PRR) and opsonin in the immune defense against invading pathogen in oyster. Moreover, as the most primitive specie with homolog of JAMs, the information of CgJAM-A-L in oyster would provide useful clues for the evolutionary study of JAMs and immunoglobulins. Copyright © 2015 Elsevier Ltd. All rights reserved.

Emergent SO(3) Symmetry of the Frictionless Shear Jamming Transition

NASA Astrophysics Data System (ADS)

Baity-Jesi, Marco; Goodrich, Carl P.; Liu, Andrea J.; Nagel, Sidney R.; Sethna, James P.

2017-05-01

We study the shear jamming of athermal frictionless soft spheres, and find that in the thermodynamic limit, a shear-jammed state exists with different elastic properties from the isotropically-jammed state. For example, shear-jammed states can have a non-zero residual shear stress in the thermodynamic limit that arises from long-range stress-stress correlations. As a result, the ratio of the shear and bulk moduli, which in isotropically-jammed systems vanishes as the jamming transition is approached from above, instead approaches a constant. Despite these striking differences, we argue that in a deeper sense, the shear jamming and isotropic jamming transitions actually have the same symmetry, and that the differences can be fully understood by rotating the six-dimensional basis of the elastic modulus tensor.

Low junctional adhesion molecule A expression correlates with poor prognosis in gastric cancer.

PubMed

Huang, Jin-Yu; Xu, Ying-Ying; Sun, Zhe; Wang, Zhen-Ning; Zhu, Zhi; Song, Yong-Xi; Luo, Yang; Zhang, Xue; Xu, Hui-Mian

2014-12-01

The aberrant expression of junctional adhesion molecule A (JAM-A), which has a close correlation with the development, progression, metastasis, and prognosis of cancer, has been frequently reported. However, neither JAM-A expression nor its correlation with clinicopathologic variables and patient survival has been defined in gastric cancers. Moreover, little is known about the role of JAM-A in gastric cancer progression. We carried out the present study to investigate the prognostic value of JAM-A expression in gastric cancer patients. Furthermore, the biological roles of JAM-A in gastric cancer progression were also investigated. We determined JAM-A expression in 167 primary gastric cancer tissues and 94 matched adjacent non-tumor tissues by immunohistochemistry. Transwell migration assays and matrigel invasion assays were used to explore the role of JAM-A in gastric cancer cells migration and invasion. CCK-8 assays were used to examine the effect of JAM-A on the proliferation of gastric cancer cells. JAM-A was downregulated in gastric cancer tissues. Low JAM-A expression was significantly associated with tumor size, lymphatic vessel invasion, lymph node metastasis, and TNM stage. Low JAM-A expression was also significantly associated with poor disease-specific survival in gastric cancer patients. Multivariate analysis demonstrated low JAM-A expression as an independent factor predicting poor survival. In addition, JAM-A had the effect on inhibition of gastric cancer cells migration and invasion. However, JAM-A had no significant effects on proliferation of gastric cancer cells. Low JAM-A expression correlates with poor clinical outcome and promotes cell migration and invasion in gastric cancer. Copyright © 2014 Elsevier Inc. All rights reserved.

Junctional adhesion molecule-C promotes metastatic potential of HT1080 human fibrosarcoma.

PubMed

Fuse, Chiaki; Ishida, Yuuki; Hikita, Tomoya; Asai, Tomohiro; Oku, Naoto

2007-03-16

The junctional adhesion molecule (JAM) family is a key molecule in a process called transendothelial migration or diapedesis. Here, we report implications of JAM-C in cancer metastasis. We first determined the mRNA expression of JAMs in 19 kinds of cancer cell lines. JAM-C was expressed in most of tumors having potent metastatic properties. Especially in murine K-1735 melanoma cell lines, the highly metastatic sublines (M2 and X21) strongly expressed JAM-C when compared with the poorly metastatic ones (C-10 and C23). Next, we investigated the role of JAM-C in cancer metastasis by using human JAM-C (hJAM-C) gene-transfected HT1080 fibrosarcoma cells. In comparison with mock-transfected HT1080 cells, these cells showed a significant increase in the adhesion to various extracellular substrates and the invasion across a Matrigel-coated membrane. The knockdown of hJAM-C using small interfering RNA resulted in the suppression of both the adhesion and the invasion of HT1080 cells, suggesting that endogenous hJAM-C might be involved in tumor metastasis. Finally, we studied the role of hJAM-C in an in vivo experimental metastatic model. The results showed that the overexpression of hJAM-C in HT1080 cells significantly decreased the life spans of the tumorbearing mice. In contrast, the knockdown of hJAM-C in HT1080 cells suppressed the weight gain of the lungs with metastatic colonies. We conclude that the expression of JAM-C promotes metastasis by enhancing both the adhesion of cancer cells to extracellular matrices and the subsequent invasion.

Glycemic index and postprandial blood glucose response to Japanese strawberry jam in normal adults.

PubMed

Kurotobi, Tomoka; Fukuhara, Kimiaki; Inage, Hiroko; Kimura, Shuichi

2010-01-01

We investigated in 30 healthy adults the glycemic index (GI) of five strawberry jams made from various sugar compositions. The jam containing the highest ratio of glucose showed a high GI, while that containing a high ratio of fructose, a jam made from polydextrose, showed a low GI. There was a high correlation (r=0.969, p=0.006) between the GI and the predicted GI calculated from the sugar composition of the jams. Moreover, the influence on postprandial blood glucose response after an intake of only 20 g of jam and one slice of bread with 20 g jam was measured in 8 healthy adults. The blood glucose level after an intake of 20 g of the high GI jam containing the high glucose ratio was higher than that of other jams at 15 min, but there was no significant difference after 30 min. Regardless of whether the GI was low or high, differences in the jams were not observed in the postprandial blood glucose level or the area under the curve after eating either one slice of bread (60 g) or one slice of bread with less than 20 g of jam.

Study of Optimum Simulation Techniques for the Design and Evaluation of Anti-Jam Communication Systems

DTIC Science & Technology

1976-03-01

pseudo -ranae and range rate correlations , and GDM software etficiency. Other simplifications include the eliwination of all or part of che multipath...signal is available. Then the pdf parameters are trivially available by simple mean, variance and correlation measurements on the quadrature signal...This report investigates the application of CSEL to the LES 8/9 and GPS satellite programs. In addition, a new analysis of the effects of soft and

Fidaxomicin jams Mycobacterium tuberculosis RNA polymerase motions needed for initiation via RbpA contacts

PubMed Central

Lilic, Mirjana; Palka, Margaret; Mooney, Rachel Anne; Landick, Robert

2018-01-01

Fidaxomicin (Fdx) is an antimicrobial RNA polymerase (RNAP) inhibitor highly effective against Mycobacterium tuberculosis RNAP in vitro, but clinical use of Fdx is limited to treating Clostridium difficile intestinal infections due to poor absorption. To identify the structural determinants of Fdx binding to RNAP, we determined the 3.4 Å cryo-electron microscopy structure of a complete M. tuberculosis RNAP holoenzyme in complex with Fdx. We find that the actinobacteria general transcription factor RbpA contacts fidaxomycin, explaining its strong effect on M. tuberculosis. Additional structures define conformational states of M. tuberculosis RNAP between the free apo-holoenzyme and the promoter-engaged open complex ready for transcription. The results establish that Fdx acts like a doorstop to jam the enzyme in an open state, preventing the motions necessary to secure promoter DNA in the active site. Our results provide a structural platform to guide development of anti-tuberculosis antimicrobials based on the Fdx binding pocket. PMID:29480804

JAM related proteins in mucosal homeostasis and inflammation

PubMed Central

Luissint, Anny-Claude; Nusrat, Asma; Parkos, Charles A.

2014-01-01

Mucosal surfaces are lined by epithelial cells that form a physical barrier protecting the body against external noxious substances and pathogens. At a molecular level, the mucosal barrier is regulated by tight junctions (TJs) that seal the paracellular space between adjacent epithelial cells. Transmembrane proteins within TJs include Junctional Adhesion Molecules (JAMs) that belong to the CTX (Cortical Thymocyte marker for Xenopus) family of proteins. JAM family encompasses three classical members (JAM-A, -B and –C) and related molecules including JAM4, JAM-Like protein (JAM-L), Coxsackie and Adenovirus Receptor (CAR), CAR-Like Membrane Protein (CLMP) and Endothelial cell-Selective Adhesion Molecule (ESAM). JAMs have multiple functions that include regulation of endothelial and epithelial paracellular permeability, leukocyte recruitment during inflammation, angiogenesis, cell migration and proliferation. In this review, we summarize the current knowledge regarding the roles of the JAM family members in the regulation of mucosal homeostasis and leukocyte trafficking with a particular emphasis on barrier function and its perturbation during pathological inflammation. PMID:24667924

Dynamic shear jamming in granular suspensions

NASA Astrophysics Data System (ADS)

Peters, Ivo; Majumdar, Sayantan; Jaeger, Heinrich

2014-11-01

Jamming by shear allows a frictional granular packing to transition from an unjammed state into a jammed state while keeping the system volume and average packing fraction constant. Shear jamming of dry granular media can occur quasi-statically, but boundaries are crucial to confine the material. We perform experiments in aqueous starch suspension where we apply shear using a rheometer with a large volume (400 ml) cylindrical Couette cell. In our suspensions the packing fraction is sufficiently low that quasi-static deformation does not induce a shear jammed state. Applying a shock-like deformation however, will turn the suspension into a jammed solid. A fully jammed state is reached within tens of microseconds, and can be sustained for at least several seconds. High speed imaging of the initial process reveals a jamming front propagating radially outward through the suspension, while the suspension near the outer boundary remains quiescent. This indicates that granular suspensions can be shear jammed without the need of confining solid boundaries. Instead, confinement is most likely provided by the dynamics in the front region.

Basic helix-loop-helix transcription factors JASMONATE-ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3 are negative regulators of jasmonate responses in Arabidopsis.

PubMed

Sasaki-Sekimoto, Yuko; Jikumaru, Yusuke; Obayashi, Takeshi; Saito, Hikaru; Masuda, Shinji; Kamiya, Yuji; Ohta, Hiroyuki; Shirasu, Ken

2013-09-01

Jasmonates regulate transcriptional reprogramming during growth, development, and defense responses. Jasmonoyl-isoleucine, an amino acid conjugate of jasmonic acid (JA), is perceived by the protein complex composed of the F-box protein CORONATINE INSENSITIVE1 (COI1) and JASMONATE ZIM DOMAIN (JAZ) proteins, leading to the ubiquitin-dependent degradation of JAZ proteins. This activates basic helix-loop-helix-type MYC transcription factors to regulate JA-responsive genes. Here, we show that the expression of genes encoding other basic helix-loop-helix transcription factors, JASMONATE ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3, is positively regulated in a COI1- and MYC2-dependent manner in Arabidopsis (Arabidopsis thaliana). However, contrary to myc2, the jam1jam2jam3 triple mutant exhibited shorter roots when treated with methyl jasmonate (MJ), indicating enhanced responsiveness to JA. Our genome-wide expression analyses revealed that key jasmonate metabolic genes as well as a set of genes encoding transcription factors that regulate the JA-responsive metabolic genes are negatively regulated by JAMs after MJ treatment. Consistently, loss of JAM genes resulted in higher accumulation of anthocyanin in MJ-treated plants as well as higher accumulation of JA and 12-hydroxyjasmonic acid in wounded plants. These results show that JAMs negatively regulate the JA responses in a manner that is mostly antagonistic to MYC2.

Basic Helix-Loop-Helix Transcription Factors JASMONATE-ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3 Are Negative Regulators of Jasmonate Responses in Arabidopsis1[W][OPEN

PubMed Central

Sasaki-Sekimoto, Yuko; Jikumaru, Yusuke; Obayashi, Takeshi; Saito, Hikaru; Masuda, Shinji; Kamiya, Yuji; Ohta, Hiroyuki; Shirasu, Ken

2013-01-01

Jasmonates regulate transcriptional reprogramming during growth, development, and defense responses. Jasmonoyl-isoleucine, an amino acid conjugate of jasmonic acid (JA), is perceived by the protein complex composed of the F-box protein CORONATINE INSENSITIVE1 (COI1) and JASMONATE ZIM DOMAIN (JAZ) proteins, leading to the ubiquitin-dependent degradation of JAZ proteins. This activates basic helix-loop-helix-type MYC transcription factors to regulate JA-responsive genes. Here, we show that the expression of genes encoding other basic helix-loop-helix transcription factors, JASMONATE ASSOCIATED MYC2-LIKE1 (JAM1), JAM2, and JAM3, is positively regulated in a COI1- and MYC2-dependent manner in Arabidopsis (Arabidopsis thaliana). However, contrary to myc2, the jam1jam2jam3 triple mutant exhibited shorter roots when treated with methyl jasmonate (MJ), indicating enhanced responsiveness to JA. Our genome-wide expression analyses revealed that key jasmonate metabolic genes as well as a set of genes encoding transcription factors that regulate the JA-responsive metabolic genes are negatively regulated by JAMs after MJ treatment. Consistently, loss of JAM genes resulted in higher accumulation of anthocyanin in MJ-treated plants as well as higher accumulation of JA and 12-hydroxyjasmonic acid in wounded plants. These results show that JAMs negatively regulate the JA responses in a manner that is mostly antagonistic to MYC2. PMID:23852442

Mechanisms of jamming in the Nagel-Schreckenberg model for traffic flow.

PubMed

Bette, Henrik M; Habel, Lars; Emig, Thorsten; Schreckenberg, Michael

2017-01-01

We study the Nagel-Schreckenberg cellular automata model for traffic flow by both simulations and analytical techniques. To better understand the nature of the jamming transition, we analyze the fraction of stopped cars P(v=0) as a function of the mean car density. We present a simple argument that yields an estimate for the free density where jamming occurs, and show satisfying agreement with simulation results. We demonstrate that the fraction of jammed cars P(v∈{0,1}) can be decomposed into the three factors (jamming rate, jam lifetime, and jam size) for which we derive, from random walk arguments, exponents that control their scaling close to the critical density.

Mechanisms of jamming in the Nagel-Schreckenberg model for traffic flow

NASA Astrophysics Data System (ADS)

Bette, Henrik M.; Habel, Lars; Emig, Thorsten; Schreckenberg, Michael

2017-01-01

We study the Nagel-Schreckenberg cellular automata model for traffic flow by both simulations and analytical techniques. To better understand the nature of the jamming transition, we analyze the fraction of stopped cars P (v =0 ) as a function of the mean car density. We present a simple argument that yields an estimate for the free density where jamming occurs, and show satisfying agreement with simulation results. We demonstrate that the fraction of jammed cars P (v ∈{0 ,1 }) can be decomposed into the three factors (jamming rate, jam lifetime, and jam size) for which we derive, from random walk arguments, exponents that control their scaling close to the critical density.

Methods for developing jam-resistant security communications networks at fixed-site facilities

NASA Astrophysics Data System (ADS)

Gangel, D. J.; Heustess, J. E.; Snell, M. K.

Considerable work has been done identifying and developing equipment and procedures that can be used to improve the survivability of a security communications network during a jamming assault. Insight is given into alternate communications methods that can be used to develop resistance to jamming by supplementing existing radio communications. The spatial properties of jamming are then discussed and examples of how these properties can be explocited are examined. Also discussed are spread-spectrum radios that are highly resistant to jamming and the importance of jamming exercises.

Low Cost Anti-Jam Digital Data-Links Techniques Investigations. Volume II.

DTIC Science & Technology

1979-05-01

to spectrum-spreading factors of the order of lO 3 to 104. It is also shown that the amount of gain is a function not only of the interference to...from a standard coherent product demodulation of the band-pass radio-frequency signal. A vector-Markov data generating model is hypothesized, as in...E/N( where S is total carrier power, K is number of samples per symbol, and L(AO) is a modulation loss factor of the modulation index, A . L(AO

GPS and Galileo: Friendly Foes? (Walker Paper, Number 12)

DTIC Science & Technology

2008-05-01

their data, others employ different techniques. US defense contractor Lockheed Martin developed an anti-jam GPS receiver in 2000 for its joint air...26. Jolis , “Problems Run Rampant for Galileo Project.” 27. Ibid. 28. “Galileo, Involving Europe,” 23. 29. Ibid., 16. 30. Ibid., 17. Assuming that by...Told to Put House in Order.” 38. EC, “Galileo, Involving Europe,” 5. 39. “Galileo Adrift in European Outer Space.” 40. Jolis , “Problems Run Rampant

Command, Control, Communications And Intelligence (C3I) Project Book, Fiscal Year 1993

DTIC Science & Technology

1992-10-30

trailers . PM MILSTAR will integrate the GNDCPs into the Army force structure. , . A /" " 1 9S. N/TRC -194 HISTORICAL BACKGROUND: Feb 89 - Army assigns...configuration consists of an S-250 shelter mounted on a truck with a trailer and generator. SCOTT is the ground segment terminal . of the Milstar system...WITH A TRAILER MOUNTED THREE KILOWATT GENERATOR AND ANTENNA. MILSCOTT/11 11-2 PM. MILSTAR (ARMY) SECURE MOBILE ANTI-JAM RELIABLE TACTICAL TERMINAL

Study on index system of GPS interference effect evaluation

NASA Astrophysics Data System (ADS)

Zhang, Kun; Zeng, Fangling; Zhao, Yuan; Zeng, Ruiqi

2018-05-01

Satellite navigation interference effect evaluation is the key technology to break through the research of Navigation countermeasure. To evaluate accurately the interference degree and Anti-jamming ability of GPS receiver, this text based on the existing research results of Navigation interference effect evaluation, build the index system of GPS receiver effectiveness evaluation from four levels of signal acquisition, tracking, demodulation and positioning/timing and establish the model for each index. These indexes can accurately and quantitatively describe the interference effect at all levels.

Genetic, structural, and chemical insights into the dual function of GRASP55 in germ cell Golgi remodeling and JAM-C polarized localization during spermatogenesis.

PubMed

Cartier-Michaud, Amandine; Bailly, Anne-Laure; Betzi, Stéphane; Shi, Xiaoli; Lissitzky, Jean-Claude; Zarubica, Ana; Sergé, Arnauld; Roche, Philippe; Lugari, Adrien; Hamon, Véronique; Bardin, Florence; Derviaux, Carine; Lembo, Frédérique; Audebert, Stéphane; Marchetto, Sylvie; Durand, Bénédicte; Borg, Jean-Paul; Shi, Ning; Morelli, Xavier; Aurrand-Lions, Michel

2017-06-01

Spermatogenesis is a dynamic process that is regulated by adhesive interactions between germ and Sertoli cells. Germ cells express the Junctional Adhesion Molecule-C (JAM-C, encoded by Jam3), which localizes to germ/Sertoli cell contacts. JAM-C is involved in germ cell polarity and acrosome formation. Using a proteomic approach, we demonstrated that JAM-C interacted with the Golgi reassembly stacking protein of 55 kDa (GRASP55, encoded by Gorasp2) in developing germ cells. Generation and study of Gorasp2-/- mice revealed that knock-out mice suffered from spermatogenesis defects. Acrosome formation and polarized localization of JAM-C in spermatids were altered in Gorasp2-/- mice. In addition, Golgi morphology of spermatocytes was disturbed in Gorasp2-/- mice. Crystal structures of GRASP55 in complex with JAM-C or JAM-B revealed that GRASP55 interacted via PDZ-mediated interactions with JAMs and induced a conformational change in GRASP55 with respect of its free conformation. An in silico pharmacophore approach identified a chemical compound called Graspin that inhibited PDZ-mediated interactions of GRASP55 with JAMs. Treatment of mice with Graspin hampered the polarized localization of JAM-C in spermatids, induced the premature release of spermatids and affected the Golgi morphology of meiotic spermatocytes.

FH/MFSK performance in multitone jamming

NASA Technical Reports Server (NTRS)

Levitt, B. K.

1985-01-01

The performance of frequency-hopped (FH) M-ary frequency-shift keyed (MFSK) signals in partial-band noise was analyzed in the open literature. The previous research is extended to the usually more effective class of multitone jamming. Some objectives researched are: (1) To categorize several different multitone jamming strategies; (2) To analyze the performance of FH/MSFK signaling, both uncoded with diversity, assuming a noncoherent energy detection metric with linear combining and perfect jamming state side information, in the presence of worst case interference for each of these multitone categories; and (3) To compare the effectiveness of the various multitone jamming techniques, and contrast the results with the partial band noise jamming case.

Mobility of large woody debris (LWD) jams in a low gradient channel

NASA Astrophysics Data System (ADS)

Curran, Joanna C.

2010-04-01

Mobility of large woody debris (LWD) in low gradient channels is an important but often overlooked transport process. The majority of studies on LWD have focused on its role in geomorphic and ecologic river processes. When jams extend across the width of the channel, they have the potential to retain sediment and alter the channel profile. When jams obstruct only a portion of the channel, they can re-direct flow, altering patterns of scour and deposition. The boundary complexity created by LWD has a recognized role in riverine ecosystems which has led to programs of replacing LWD in-channel corridors where it was previously removed. Although LWD jams are common in rivers around the world, they have been studied most intensely in steep, forested channel reaches where they are often found to be stable channel features. It is not fully known how much of the information on LWD from steep forested channels will transfer to other channel types. Whereas it may be reasonable to assume that the ecological benefits of LWD are similar in low gradient channels, research has shown that a much higher rate of LWD transport occurs in low gradient channels, with jams mobilized on timescales of 10 0-10 2 years. This study evaluates the distribution and mobility of LWD over 72 km of the San Antonio River, a low gradient channel in southeast Texas. LWD jam locations were identified for 2003 and 2007 using a combination of aerial photography and field mapping. Each jam was cataloged according to its location in the channel cross-section and the amount of channel area blocked. During the four-year period, all the LWD jams were mobilized, including those jams extending across the channel width. Although easily mobilized, 34 jams re-form in the same locations, creating 34 channel locations with persistent LWD jams. Data from the San Antonio River are applied to two models developed to predict LWD mobility and transport distances to assess the applicability of each model to a low gradient channel. The locations of stable (or recurring) LWD jams were matched to model results where predicted LWD transport distances were equal to measured LWD jam spacing. Model results showed good agreement with the mean and median spacing of LWD jams when given input parameters specific to the channel and wood species. The ability to predict where LWD jams will persist over time in a low gradient channel has application in watershed management. Persistent LWD jams can exert a greater influence on channel morphology and may require active management.

Self-Organization in 2D Traffic Flow Model with Jam-Avoiding Drive

NASA Astrophysics Data System (ADS)

Nagatani, Takashi

1995-04-01

A stochastic cellular automaton (CA) model is presented to investigate the traffic jam by self-organization in the two-dimensional (2D) traffic flow. The CA model is the extended version of the 2D asymmetric exclusion model to take into account jam-avoiding drive. Each site contains either a car moving to the up, a car moving to the right, or is empty. A up car can shift right with probability p ja if it is blocked ahead by other cars. It is shown that the three phases (the low-density phase, the intermediate-density phase and the high-density phase) appear in the traffic flow. The intermediate-density phase is characterized by the right moving of up cars. The jamming transition to the high-density jamming phase occurs with higher density of cars than that without jam-avoiding drive. The jamming transition point p 2c increases with the shifting probability p ja. In the deterministic limit of p ja=1, it is found that a new jamming transition occurs from the low-density synchronized-shifting phase to the high-density moving phase with increasing density of cars. In the synchronized-shifting phase, all up cars do not move to the up but shift to the right by synchronizing with the move of right cars. We show that the jam-avoiding drive has an important effect on the dynamical jamming transition.

21 CFR 150.160 - Fruit preserves and jams.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Fruit preserves and jams. 150.160 Section 150.160... jams. (a) The preserves or jams for which definitions and standards of identity are prescribed by this..., Pineapple, Raspberry, red raspberry, Rhubarb, Strawberry, Tangerine, Tomato, Yellow tomato, Youngberry Group...

Unjamming and cell shape in the asthmatic airway epithelium

NASA Astrophysics Data System (ADS)

Park, Jin-Ah; Kim, Jae Hun; Bi, Dapeng; Mitchel, Jennifer A.; Qazvini, Nader Taheri; Tantisira, Kelan; Park, Chan Young; McGill, Maureen; Kim, Sae-Hoon; Gweon, Bomi; Notbohm, Jacob; Steward, Robert, Jr.; Burger, Stephanie; Randell, Scott H.; Kho, Alvin T.; Tambe, Dhananjay T.; Hardin, Corey; Shore, Stephanie A.; Israel, Elliot; Weitz, David A.; Tschumperlin, Daniel J.; Henske, Elizabeth P.; Weiss, Scott T.; Manning, M. Lisa; Butler, James P.; Drazen, Jeffrey M.; Fredberg, Jeffrey J.

2015-10-01

From coffee beans flowing in a chute to cells remodelling in a living tissue, a wide variety of close-packed collective systems--both inert and living--have the potential to jam. The collective can sometimes flow like a fluid or jam and rigidify like a solid. The unjammed-to-jammed transition remains poorly understood, however, and structural properties characterizing these phases remain unknown. Using primary human bronchial epithelial cells, we show that the jamming transition in asthma is linked to cell shape, thus establishing in that system a structural criterion for cell jamming. Surprisingly, the collapse of critical scaling predicts a counter-intuitive relationship between jamming, cell shape and cell-cell adhesive stresses that is borne out by direct experimental observations. Cell shape thus provides a rigorous structural signature for classification and investigation of bronchial epithelial layer jamming in asthma, and potentially in any process in disease or development in which epithelial dynamics play a prominent role.

JAM-C regulates tight junctions and integrin-mediated cell adhesion and migration.

PubMed

Mandicourt, Guillaume; Iden, Sandra; Ebnet, Klaus; Aurrand-Lions, Michel; Imhof, Beat A

2007-01-19

Junctional Adhesion Molecules (JAMs) have been described as major components of tight junctions in endothelial and epithelial cells. Tight junctions are crucial for the establishment and maintenance of cell polarity. During tumor development, they are remodeled, enabling neoplastic cells to escape from constraints imposed by intercellular junctions and to adopt a migratory behavior. Using a carcinoma cell line we tested whether JAM-C could affect tight junctions and migratory properties of tumor cells. We show that transfection of JAM-C improves the tight junctional barrier in tumor cells devoid of JAM-C expression. This is dependent on serine 281 in the cytoplasmic tail of JAM-C because serine mutation into alanine abolishes the specific localization of JAM-C in tight junctions and establishment of cell polarity. More importantly, the same mutation stimulates integrin-mediated cell migration and adhesion via the modulation of beta1 and beta3 integrin activation. These results highlight an unexpected function for JAM-C in controlling epithelial cell conversion from a static, polarized state to a pro-migratory phenotype.

[Inactivating Effect of Heat-Denatured Lysozyme on Murine Norovirus in Bread Fillings].

PubMed

Takahashi, Michiko; Yasuda, Yuka; Takahashi, Hajime; Takeuchi, Akira; Kuda, Takashi; Kimura, Bon

2018-01-01

In this study, we investigated the viability of murine norovirus strain 1 (MNV-1), a surrogate for human norovirus, in bread fillings used for making stuffed buns and pastries. The inactivating effect of heat-denatured lysozyme, which was recently reported to have an antiviral effect, on MNV-1 contaminating the bread fillings was also examined. MNV-1 was inoculated into two types of fillings (chocolate cream, marmalade jam) at 4.5 log PFU/g, and the bread fillings were stored at 4℃ for 5 days. MNV-1 remained viable in the bread fillings during storage. However, addition of 1% heat-denatured lysozyme to the fillings resulted in a decrease of MNV-1 infectivity immediately after inoculation, in both fillings. On the fifth day of storage, MNV-1 infectivity was decreased by 1.2 log PFU/g in chocolate cream and by 0.9 log PFU/g in marmalade jam. Although the mechanism underlying the anti-norovirus effect of heat-denatured lysozyme has not been clarified, our results suggest that heat-denatured lysozyme can be used as an inactivating agent against norovirus in bread fillings.

Stronger at Depth: Jamming Grippers as Deep Sea Sampling Tools.

PubMed

Licht, Stephen; Collins, Everett; Mendes, Manuel Lopes; Baxter, Christopher

2017-12-01

In this work we experimentally demonstrate (a) that the holding strength of universal jamming grippers increases as a function of the jamming pressure to greater than three atmospheres, and (b) that jamming grippers can be operated in the deep sea in ambient pressures exceeding one hundred atmospheres, where such high jamming pressures can be readily achieved. Laboratory experiments in a pressurized, water-filled test cell are used to measure the holding force of a "universal" style jamming gripper as a function of the pressure difference between internal membrane pressure and ambient pressure. Experiments at sea are used to demonstrate that jamming grippers can be installed on, and operated from, remotely operated vehicles at depths in excess of 1200 m. In both experiments, the jamming gripper consists of a latex balloon filled with a mixture of fresh water and ∼200 μm glass beads, which are cheaply available in large quantities as sand blasting media. The use of a liquid, rather than a gas, as the fluid media allows operation of the gripper with a closed-loop fluid system; jamming pressure is controlled with an electrically driven water hydraulic cylinder in the laboratory and with an oil hydraulic-driven large-bore water hydraulic cylinder at sea.

Adaptive changes in echolocation sounds by Pipistrellus abramus in response to artificial jamming sounds.

PubMed

Takahashi, Eri; Hyomoto, Kiri; Riquimaroux, Hiroshi; Watanabe, Yoshiaki; Ohta, Tetsuo; Hiryu, Shizuko

2014-08-15

The echolocation behavior of Pipistrellus abramus during exposure to artificial jamming sounds during flight was investigated. Echolocation pulses emitted by the bats were recorded using a telemetry microphone mounted on the bats' backs, and their adaptation based on acoustic characteristics of emitted pulses was assessed in terms of jamming-avoidance responses (JARs). In experiment 1, frequency-modulated jamming sounds (3 ms duration) mimicking echolocation pulses of P. abramus were prepared. All bats showed significant increases in the terminal frequency of the frequency-modulated pulse by an average of 2.1-4.5 kHz when the terminal frequency of the jamming sounds was lower than the bats' own pulses. This frequency shift was not observed using jamming frequencies that overlapped with or were higher than the bats' own pulses. These findings suggest that JARs in P. abramus are sensitive to the terminal frequency of jamming pulses and that the bats' response pattern was dependent on the slight difference in stimulus frequency. In experiment 2, when bats were repeatedly exposed to a band-limited noise of 70 ms duration, the bats in flight more frequently emitted pulses during silent periods between jamming sounds, suggesting that the bats could actively change the timing of pulse emissions, even during flight, to avoid temporal overlap with jamming sounds. Our findings demonstrate that bats could adjust their vocalized frequency and emission timing during flight in response to acoustic jamming stimuli. © 2014. Published by The Company of Biologists Ltd.

Loss of partitioning-defective-3/isotype-specific interacting protein (par-3/ASIP) in the elongating spermatid of RA175 (IGSF4A/SynCAM)-deficient mice.

PubMed

Fujita, Eriko; Tanabe, Yuko; Hirose, Tomonori; Aurrand-Lions, Michel; Kasahara, Tadashi; Imhof, Beat A; Ohno, Shigeo; Momoi, Takashi

2007-12-01

IGSF4a/RA175/SynCAM (RA175) and junctional adhesion molecules (Jams) are members of the immunoglobulin superfamily with a PDZ-binding domain at their C termini. Deficiency of Ra175 (Ra175(-/-)) as well as Jam-C deficiency (Jam-C(-/-)) causes the defect of the spermatid differentiation, oligo-astheno-teratozoospermia. Ra175(-/-) elongating spermatids fail to mature further, whereas Jam-C(-/-) round spermatids lose cell polarity, and most of Jam-C(-/-) elongated spermatids are completely lost. RA175 and Jam-C seem to have similar but distinct functional roles during spermatid differentiation. Here we show that the cell polarity protein Par-3 with PDZ domains, a binding partner of Jams, is one of the associated proteins of the cytoplasmic region of RA175 in testis. Par-3 and Jam-C are partly co-localized with RA175 in the elongating and elongated spermatids; their distributions overlapped with that of RA175 on the tips of the dorsal region of the head of the elongating spermatid (steps 9 to 12) in the wild type. In the Ra175(-/-) elongating spermatid, Par-3 was absent, and Jam-C was absent or abnormally localized. The RA175 formed a ternary complex with Jam-C via interaction with Par-3. The lack of the ternary complex in the Ra175(-/-) elongating spermatid may cause the defect of the specialized adhesion structures, resulting in the oligo-astheno-teratozoospermia.

Jam1a-Jam2a interactions regulate haematopoietic stem cell fate through Notch signalling.

PubMed

Kobayashi, Isao; Kobayashi-Sun, Jingjing; Kim, Albert D; Pouget, Claire; Fujita, Naonobu; Suda, Toshio; Traver, David

2014-08-21

Notch signalling plays a key role in the generation of haematopoietic stem cells (HSCs) during vertebrate development and requires intimate contact between signal-emitting and signal-receiving cells, although little is known regarding when, where and how these intercellular events occur. We previously reported that the somitic Notch ligands, Dlc and Dld, are essential for HSC specification. It has remained unclear, however, how these somitic requirements are connected to the later emergence of HSCs from the dorsal aorta. Here we show in zebrafish that Notch signalling establishes HSC fate as their shared vascular precursors migrate across the ventral face of the somite and that junctional adhesion molecules (JAMs) mediate this required Notch signal transduction. HSC precursors express jam1a (also known as f11r) and migrate axially across the ventral somite, where Jam2a and the Notch ligands Dlc and Dld are expressed. Despite no alteration in the expression of Notch ligand or receptor genes, loss of function of jam1a led to loss of Notch signalling and loss of HSCs. Enforced activation of Notch in shared vascular precursors rescued HSCs in jam1a or jam2a deficient embryos. Together, these results indicate that Jam1a-Jam2a interactions facilitate the transduction of requisite Notch signals from the somite to the precursors of HSCs, and that these events occur well before formation of the dorsal aorta.

Cloning and preliminary functional studies of the JAM-A gene in grass carp (Ctenopharyngodon idellus).

PubMed

Du, Fukuan; Su, Jianguo; Huang, Rong; Liao, Lanjie; Zhu, Zuoyan; Wang, Yaping

2013-06-01

Grass carp (Ctenopharyngodon idellus) is a very important aquaculture species in China and other South-East Asian countries; however, disease outbreaks in this species are frequent, resulting in huge economic losses. Grass carp hemorrhage caused by grass carp reovirus (GCRV) is one of the most serious diseases. Junction adhesion molecule A (JAM-A) is the mammalian receptor for reovirus, and has been well studied. However, the JAM-A gene in grass carp has not been studied so far. In this study, we cloned and elucidated the structure of the JAM-A gene in grass carp (GcJAM-A) and then studied its functions during grass carp hemorrhage. GcJAM-A is composed of 10 exons and 9 introns, and its full-length cDNA is 1833 bp long, with an 888 bp open reading frame (ORF) that encodes a 295 amino acid protein. The GcJAM-A protein is predicted to contain a typical transmembrane domain. Maternal expression pattern of GcJAM-A is observed during early embryogenesis, while zygote expression occurs at 8 h after hatching. GcJAM-A is expressed strongly in the gill, liver, intestine and kidney, while it is expressed poorly in the blood, brain, spleen and head kidney. Moreover, lower expression is observed in the gill, liver, intestine, brain, spleen and kidney of 30-month-old individuals, compared with 6-month-old. In a GcJAM-A-knockdown cell line (CIK) infected with GCRV, the expression of genes involved in the interferon and apoptosis pathways was significantly inhibited. These results suggest that GcJAM-A could be a receptor for GCRV. We have therefore managed to characterize the GcJAM-A gene and provide evidence for its role as a receptor for GCRV. Crown Copyright © 2013. Published by Elsevier Ltd. All rights reserved.

Hyperreactivity of junctional adhesion molecule A-deficient platelets accelerates atherosclerosis in hyperlipidemic mice.

PubMed

Karshovska, Ela; Zhao, Zhen; Blanchet, Xavier; Schmitt, Martin M N; Bidzhekov, Kiril; Soehnlein, Oliver; von Hundelshausen, Philipp; Mattheij, Nadine J; Cosemans, Judith M E M; Megens, Remco T A; Koeppel, Thomas A; Schober, Andreas; Hackeng, Tilman M; Weber, Christian; Koenen, Rory R

2015-02-13

Besides their essential role in hemostasis, platelets also have functions in inflammation. In platelets, junctional adhesion molecule (JAM)-A was previously identified as an inhibitor of integrin αIIbβ3-mediated outside-in signaling and its genetic knockdown resulted in hyperreactivity. This gain-of-function was specifically exploited to investigate the role of platelet hyperreactivity in plaque development. JAM-A-deficient platelets showed increased aggregation and cellular and sarcoma tyrosine-protein kinase activation. On αIIbβ3 ligation, JAM-A was shown to be dephosphorylated, which could be prevented by protein tyrosine phosphatase nonreceptor type 1 inhibition. Mice with or without platelet-specific (tr)JAM-A-deficiency in an apolipoprotein e (apoe(-/-)) background were fed a high-fat diet. After ≤12 weeks of diet, trJAM-A(-/-)apoe-/- mice showed increased aortic plaque formation when compared with trJAM-A(+/+) apoe(-/-) controls, and these differences were most evident at early time points. At 2 weeks, the plaques of the trJAM-A(-/-) apoe(-/-) animals revealed increased macrophage, T cell, and smooth muscle cell content. Interestingly, plasma levels of chemokines CC chemokine ligand 5 and CXC-chemokine ligand 4 were increased in the trJAM-A(-/-) apoe(-/-)mice, and JAM-A-deficient platelets showed increased binding to monocytes and neutrophils. Whole-blood perfusion experiments and intravital microscopy revealed increased recruitment of platelets and monocytes to the inflamed endothelium in blood of trJAM-A(-/-) apoe(-/-)mice. Notably, these proinflammatory effects of JAM-A-deficient platelets could be abolished by the inhibition of αIIbβ3 signaling in vitro. Deletion of JAM-A causes a gain-of-function in platelets, with lower activation thresholds and increased inflammatory activities. This leads to an increase of plaque formation, particularly in early stages of the disease. © 2014 American Heart Association, Inc.

Junctional Adhesion Molecule A Serves as a Receptor for Prototype and Field-Isolate Strains of Mammalian Reovirus

PubMed Central

Campbell, Jacquelyn A.; Schelling, Pierre; Wetzel, J. Denise; Johnson, Elizabeth M.; Forrest, J. Craig; Wilson, Greame A. R.; Aurrand-Lions, Michel; Imhof, Beat A.; Stehle, Thilo; Dermody, Terence S.

2005-01-01

Reovirus infections are initiated by the binding of viral attachment protein σ1 to receptors on the surface of host cells. The σ1 protein is an elongated fiber comprised of an N-terminal tail that inserts into the virion and a C-terminal head that extends from the virion surface. The prototype reovirus strains type 1 Lang/53 (T1L/53) and type 3 Dearing/55 (T3D/55) use junctional adhesion molecule A (JAM-A) as a receptor. The C-terminal half of the T3D/55 σ1 protein interacts directly with JAM-A, but the determinants of receptor-binding specificity have not been identified. In this study, we investigated whether JAM-A also mediates the attachment of the prototype reovirus strain type 2 Jones/55 (T2J/55) and a panel of field-isolate strains representing each of the three serotypes. Antibodies specific for JAM-A were capable of inhibiting infections of HeLa cells by T1L/53, T2J/55, and T3D/55, demonstrating that strains of all three serotypes use JAM-A as a receptor. To corroborate these findings, we introduced JAM-A or the structurally related JAM family members JAM-B and JAM-C into Chinese hamster ovary cells, which are poorly permissive for reovirus infection. Both prototype and field-isolate reovirus strains were capable of infecting cells transfected with JAM-A but not those transfected with JAM-B or JAM-C. A sequence analysis of the σ1-encoding S1 gene segment of the strains chosen for study revealed little conservation in the deduced σ1 amino acid sequences among the three serotypes. This contrasts markedly with the observed sequence variability within each serotype, which is confined to a small number of amino acids. Mapping of these residues onto the crystal structure of σ1 identified regions of conservation and variability, suggesting a likely mode of JAM-A binding via a conserved surface at the base of the σ1 head domain. PMID:15956543

Smeared spectrum jamming suppression based on generalized S transform and threshold segmentation

NASA Astrophysics Data System (ADS)

Li, Xin; Wang, Chunyang; Tan, Ming; Fu, Xiaolong

2018-04-01

Smeared Spectrum (SMSP) jamming is an effective jamming in countering linear frequency modulation (LFM) radar. According to the time-frequency distribution difference between jamming and echo, a jamming suppression method based on Generalized S transform (GST) and threshold segmentation is proposed. The sub-pulse period is firstly estimated based on auto correlation function firstly. Secondly, the time-frequency image and the related gray scale image are achieved based on GST. Finally, the Tsallis cross entropy is utilized to compute the optimized segmentation threshold, and then the jamming suppression filter is constructed based on the threshold. The simulation results show that the proposed method is of good performance in the suppression of false targets produced by SMSP.

Fuzzy PID control algorithm based on PSO and application in BLDC motor

NASA Astrophysics Data System (ADS)

Lin, Sen; Wang, Guanglong

2017-06-01

A fuzzy PID control algorithm is studied based on improved particle swarm optimization (PSO) to perform Brushless DC (BLDC) motor control which has high accuracy, good anti-jamming capability and steady state accuracy compared with traditional PID control. The mathematical and simulation model is established for BLDC motor by simulink software, and the speed loop of the fuzzy PID controller is designed. The simulation results show that the fuzzy PID control algorithm based on PSO has higher stability, high control precision and faster dynamic response speed.

Development of software and hardware models of monitoring, control, and data transfer to improve safety of downhole motor during drilling

NASA Astrophysics Data System (ADS)

Kostarev, S. N.; Sereda, T. G.

2017-10-01

The article is concerned with the problem of transmitting data from telemetric devices in order to provide automated systems for the electric drive control of oil-extracting equipment. The paper given discusses the possibility to use a logging cable as means of signal transfer. Simulation models of signaling and relay-contact circuits for monitoring critical drive parameters are under discussion. The authors suggest applying the operator ⊕ (excluding OR) to increase anti-jamming effects and to get a more reliable noise filter.

Design and Implementation of a Wireless Sensor Network-Based Remote Water-Level Monitoring System

PubMed Central

Li, Xiuhong; Cheng, Xiao; Gong, Peng; Yan, Ke

2011-01-01

The proposed remote water-level monitoring system (RWMS) consists of a field sensor module, a base station module, adata center module and aWEB releasing module. It has advantages in real time and synchronized remote control, expandability, and anti-jamming capabilities. The RWMS can realize real-time remote monitoring, providing early warning of events and protection of the safety of monitoring personnel under certain dangerous circumstances. This system has been successfully applied in Poyanghu Lake. The cost of the whole system is approximately 1,500 yuan (RMB). PMID:22319377

Design and implementation of a wireless sensor network-based remote water-level monitoring system.

PubMed

Li, Xiuhong; Cheng, Xiao; Gong, Peng; Yan, Ke

2011-01-01

The proposed remote water-level monitoring system (RWMS) consists of a field sensor module, a base station module, a data center module and a WEB releasing module. It has advantages in real time and synchronized remote control, expandability, and anti-jamming capabilities. The RWMS can realize real-time remote monitoring, providing early warning of events and protection of the safety of monitoring personnel under certain dangerous circumstances. This system has been successfully applied in Poyanghu Lake. The cost of the whole system is approximately 1,500 yuan (RMB).

Loss of Partitioning-Defective-3/Isotype-Specific Interacting Protein (Par-3/ASIP) in the Elongating Spermatid of RA175 (IGSF4A/SynCAM)-Deficient Mice

PubMed Central

Fujita, Eriko; Tanabe, Yuko; Hirose, Tomonori; Aurrand-Lions, Michel; Kasahara, Tadashi; Imhof, Beat A.; Ohno, Shigeo; Momoi, Takashi

2007-01-01

IGSF4a/RA175/SynCAM (RA175) and junctional adhesion molecules (Jams) are members of the immunoglobulin superfamily with a PDZ-binding domain at their C termini. Deficiency of Ra175 (Ra175−/−) as well as Jam-C deficiency (Jam-C−/−) causes the defect of the spermatid differentiation, oligo-astheno-teratozoospermia. Ra175−/− elongating spermatids fail to mature further, whereas Jam-C−/− round spermatids lose cell polarity, and most of Jam-C−/− elongated spermatids are completely lost. RA175 and Jam-C seem to have similar but distinct functional roles during spermatid differentiation. Here we show that the cell polarity protein Par-3 with PDZ domains, a binding partner of Jams, is one of the associated proteins of the cytoplasmic region of RA175 in testis. Par-3 and Jam-C are partly co-localized with RA175 in the elongating and elongated spermatids; their distributions overlapped with that of RA175 on the tips of the dorsal region of the head of the elongating spermatid (steps 9 to 12) in the wild type. In the Ra175−/− elongating spermatid, Par-3 was absent, and Jam-C was absent or abnormally localized. The RA175 formed a ternary complex with Jam-C via interaction with Par-3. The lack of the ternary complex in the Ra175−/− elongating spermatid may cause the defect of the specialized adhesion structures, resulting in the oligo-astheno-teratozoospermia. PMID:18055550

Evaluation of jamming efficiency for the protection of a single ground object

NASA Astrophysics Data System (ADS)

Matuszewski, Jan

2018-04-01

The electronic countermeasures (ECM) include methods to completely prevent or restrict the effective use of the electromagnetic spectrum by the opponent. The most widespread means of disorganizing the operation of electronic devices is to create active and passive radio-electronic jamming. The paper presents the way of jamming efficiency calculations for protecting ground objects against the radars mounted on the airborne platforms. The basic mathematical formulas for calculating the efficiency of active radar jamming are presented. The numerical calculations for ground object protection are made for two different electronic warfare scenarios: the jammer is placed very closely and in a determined distance from the protecting object. The results of these calculations are presented in the appropriate figures showing the minimal distance of effective jamming. The realization of effective radar jamming in electronic warfare systems depends mainly on the precise knowledge of radar and the jammer's technical parameters, the distance between them, the assumed value of the degradation coefficient, the conditions of electromagnetic energy propagation and the applied jamming method. The conclusions from these calculations facilitate making a decision regarding how jamming should be conducted to achieve high efficiency during the electronic warfare training.

Jamming effect analysis of infrared reticle seeker for directed infrared countermeasures

NASA Astrophysics Data System (ADS)

Bae, Tae-Wuk; Kim, Byoung-Ik; Kim, Young-Choon; Ahn, Sang-Ho

2012-09-01

In directed infrared countermeasures (DIRCM), the purpose of jamming toward missiles is making missiles miss the target (aircraft of our forces) in the field of view. Since the DIRCM system directly emits the pulsing flashes of infrared (IR) energy to missiles, it is more effective than present flare method emitting IR source to omni-direction. In this paper, we implemented a reticle seeker simulation tool using MATLAB-SIMULINK, in order to analyze jamming effect of spin-scan and con-scan reticle missile seeker used widely in the world, though it was developed early. Because the jammer signal has influence on the missile guidance system using its variable frequency, it is very important technique among military defense systems protecting our forces from missiles of enemy. Simulation results show that jamming effect is greatly influenced according to frequency, phase and intensity of jammer signal. Especially, jammer frequency has the largest influence on jamming effect. Through our reticle seeker simulation tool, we can confirm that jamming effect toward missiles is significantly increased when jammer frequency is similar to reticle frequency. Finally, we evaluated jamming effect according to jammer frequencies, by using correlation coefficient as an evaluation criterion of jamming performance in two reticle missile seekers.

Jamming of Cylindrical Grains in Featureless Vertical Channels

NASA Astrophysics Data System (ADS)

Baxter, G. William; Barr, Nicholas; Weible, Seth; Friedl, Nicholas

2013-03-01

We study jamming of low aspect-ratio cylindrical Delrin grains falling through a featureless vertical channel. With a grain height less than the grain diameter, these grains resemble aspirin tablets, poker chips, or coins. Unidisperse grains are allowed to fall under the influence of gravity through a uniform channel of square cross-section where the channel width is greater than the grain size and constant along the length of the channel. Channel widths are chosen so that no combination of grain heights and diameters is equal to the channel width. Collections of grains sometimes form jams, stable structures in which the grains are supported by the channel walls and not by grains or walls beneath them. The probability of a jam occurring and the jam's strength are influenced by the grain dimensions and channel width. We will present experimental measurements of the jamming probability and jam strength and discuss the relationship of these results to other experiments and theories. Supported by an Undergraduate Research Grant from Penn State Erie, The Behrend College

Target deception jamming method against spaceborne synthetic aperture radar using electromagnetic scattering

NASA Astrophysics Data System (ADS)

Sun, Qingyang; Shu, Ting; Tang, Bin; Yu, Wenxian

2018-01-01

A method is proposed to perform target deception jamming against spaceborne synthetic aperture radar. Compared with the traditional jamming methods using deception templates to cover the target or region of interest, the proposed method aims to generate a verisimilar deceptive target in various attitude with high fidelity using the electromagnetic (EM) scattering. Based on the geometrical model for target deception jamming, the EM scattering data from the deceptive target was first simulated by applying an EM calculation software. Then, the proposed jamming frequency response (JFR) is calculated offline by further processing. Finally, the deception jamming is achieved in real time by a multiplication between the proposed JFR and the spectrum of intercepted radar signals. The practical implementation is presented. The simulation results prove the validity of the proposed method.

Edwards statistical mechanics for jammed granular matter

NASA Astrophysics Data System (ADS)

Baule, Adrian; Morone, Flaviano; Herrmann, Hans J.; Makse, Hernán A.

2018-01-01

In 1989, Sir Sam Edwards made the visionary proposition to treat jammed granular materials using a volume ensemble of equiprobable jammed states in analogy to thermal equilibrium statistical mechanics, despite their inherent athermal features. Since then, the statistical mechanics approach for jammed matter—one of the very few generalizations of Gibbs-Boltzmann statistical mechanics to out-of-equilibrium matter—has garnered an extraordinary amount of attention by both theorists and experimentalists. Its importance stems from the fact that jammed states of matter are ubiquitous in nature appearing in a broad range of granular and soft materials such as colloids, emulsions, glasses, and biomatter. Indeed, despite being one of the simplest states of matter—primarily governed by the steric interactions between the constitutive particles—a theoretical understanding based on first principles has proved exceedingly challenging. Here a systematic approach to jammed matter based on the Edwards statistical mechanical ensemble is reviewed. The construction of microcanonical and canonical ensembles based on the volume function, which replaces the Hamiltonian in jammed systems, is discussed. The importance of approximation schemes at various levels is emphasized leading to quantitative predictions for ensemble averaged quantities such as packing fractions and contact force distributions. An overview of the phenomenology of jammed states and experiments, simulations, and theoretical models scrutinizing the strong assumptions underlying Edwards approach is given including recent results suggesting the validity of Edwards ergodic hypothesis for jammed states. A theoretical framework for packings whose constitutive particles range from spherical to nonspherical shapes such as dimers, polymers, ellipsoids, spherocylinders or tetrahedra, hard and soft, frictional, frictionless and adhesive, monodisperse, and polydisperse particles in any dimensions is discussed providing insight into a unifying phase diagram for all jammed matter. Furthermore, the connection between the Edwards ensemble of metastable jammed states and metastability in spin glasses is established. This highlights the fact that the packing problem can be understood as a constraint satisfaction problem for excluded volume and force and torque balance leading to a unifying framework between the Edwards ensemble of equiprobable jammed states and out-of-equilibrium spin glasses.

River predisposition to ice jams: a simplified geospatial model

NASA Astrophysics Data System (ADS)

De Munck, Stéphane; Gauthier, Yves; Bernier, Monique; Chokmani, Karem; Légaré, Serge

2017-07-01

Floods resulting from river ice jams pose a great risk to many riverside municipalities in Canada. The location of an ice jam is mainly influenced by channel morphology. The goal of this work was therefore to develop a simplified geospatial model to estimate the predisposition of a river channel to ice jams. Rather than predicting the timing of river ice breakup, the main question here was to predict where the broken ice is susceptible to jam based on the river's geomorphological characteristics. Thus, six parameters referred to potential causes for ice jams in the literature were initially selected: presence of an island, narrowing of the channel, high sinuosity, presence of a bridge, confluence of rivers, and slope break. A GIS-based tool was used to generate the aforementioned factors over regular-spaced segments along the entire channel using available geospatial data. An ice jam predisposition index (IJPI) was calculated by combining the weighted optimal factors. Three Canadian rivers (province of Québec) were chosen as test sites. The resulting maps were assessed from historical observations and local knowledge. Results show that 77 % of the observed ice jam sites on record occurred in river sections that the model considered as having high or medium predisposition. This leaves 23 % of false negative errors (missed occurrence). Between 7 and 11 % of the highly predisposed river sections did not have an ice jam on record (false-positive cases). Results, limitations, and potential improvements are discussed.

Development of new antiatherosclerotic and antithrombotic drugs utilizing F11 receptor (F11R/JAM-A) peptides.

PubMed

Babinska, A; Clement, C C; Swiatkowska, M; Szymanski, J; Shon, A; Ehrlich, Y H; Kornecki, E; Salifu, M O

2014-07-01

Peptides with enhanced resistance to proteolysis, based on the amino acid sequence of the F11 receptor molecule (F11R, aka JAM-A/Junctional adhesion molecule-A), were designed, prepared, and examined as potential candidates for the development of anti-atherosclerotic and anti-thrombotic therapeutic drugs. A sequence at the N-terminal of F11R together with another sequence located in the first Ig-loop of this protein, were identified to form a steric active-site operating in the F11R-dependent adhesion between cells that express F11R molecules on their external surface. In silico modeling of the complex between two polypeptide chains with the sequences positioned in the active-site was used to generate peptide-candidates designed to inhibit homophilic interactions between surface-located F11R molecules. The two lead F11R peptides were modified with D-Arg and D-Lys at selective sites, for attaining higher stability to proteolysis in vivo. Using molecular docking experiments we tested different conformational states and the putative binding affinity between two selected D-Arg and D-Lys-modified F11R peptides and the proposed binding pocket. The inhibitory effects of the F11R peptide 2HN-(dK)-SVT-(dR)-EDTGTYTC-CONH2 on antibody-induced platelet aggregation and on the adhesion of platelets to cytokine-inflammed endothelial cells are reported in detail, and the results point out the significant potential utilization of F11R peptides for the prevention and treatment of atherosclerotic plaques and associated thrombotic events. © 2014 Wiley Periodicals, Inc.

Cultur(ally) Jammed: Culture Jams as a Form of Culturally Responsive Teaching

ERIC Educational Resources Information Center

Martinez, Ulyssa

2012-01-01

Does the person become the name or does the name become the person? This question was asked by a participant of my culture jam entitled, "What's my name?" In this culture jam, I asked people to discern the name of a person based solely on their appearance and a list of possible names below their picture. This article aims to show how culture jams…

Effect of Friction on Shear Jamming

NASA Astrophysics Data System (ADS)

Wang, Dong; Ren, Jie; Dijksman, Joshua; Bares, Jonathan; Behringer, Robert

2015-03-01

Shear jamming of granular materials was first found for systems of frictional disks, with a static friction coefficient μ ~ 0 . 6 (Bi et al. Nature (2011)). Jamming by shear is obtained by starting from a zero-stress state with a packing fraction ϕ between ϕJ (isotropic jamming) and a lowest ϕS for shear jamming. This phenomenon is associated with strong anisotropy in stress and the contact network in the form of force chains, which are stabilized and/or enhanced by the presence of friction. Whether shear jamming occurs for frictionless particles is under debate. The issue we address experimentally is how reducing friction affects shear jamming. We put the Teflon-wrapped photoelastic disks, lowering the friction substantially from previous experiments, in a well-studied 2D shear apparatus (Ren et al. PRL (2013)), which provides a uniform simple shear. Shear jamming is still observed; however, the difference ϕJ -ϕS is smaller with lower friction. We also observe larger anisotropies in fragile states compared to experiments with higher friction particles at the same density. In ongoing work we are studying systems using photoelastic disks with fine gears on the edge to generate very large effective friction. We acknowledge support from NSF Grant DMR1206351, NSF Grant DMS-1248071, NASA Grant NNX10AU01G and William M. Keck Foundation.

Size and density avalanche scaling near jamming.

PubMed

Arévalo, Roberto; Ciamarra, Massimo Pica

2014-04-28

The current microscopic picture of plasticity in amorphous materials assumes local failure events to produce displacement fields complying with linear elasticity. Indeed, the flow properties of nonaffine systems, such as foams, emulsions and granular materials close to jamming, that produce a fluctuating displacement field when failing, are still controversial. Here we show, via a thorough numerical investigation of jammed materials, that nonaffinity induces a critical scaling of the flow properties dictated by the distance to the jamming point. We rationalize this critical behavior by introducing a new universal jamming exponent and hyperscaling relationships, and we use these results to describe the volume fraction dependence of the friction coefficient.

Systems and methods for short range RF communication

NASA Technical Reports Server (NTRS)

Hershey, John Erik (Inventor); Tomlinson, Harold Woodruff (Inventor); DeCristofaro, Richard Anthony (Inventor); Ross, John Anderson Fergus (Inventor); Sexton, Daniel White (Inventor)

2012-01-01

A method transmitting a message over at least one of a plurality of channels of a communications network is provided. The method comprises the steps of detecting a presence of jamming pulses in the at least one of the plurality of channels. The characteristics of the jamming pulses in the at least one of the plurality of channels is determined wherein the determined characteristics define at least interstices between the jamming pulses. The message is transmitted over the at least one of the plurality of channels wherein the message is transmitted within the interstices of the jamming pulse determined from the step of determining characteristics of the jamming pulses.

Exploring new kinds of relationships using generative music-making software.

PubMed

Dillon, Steve; Jones, Anita

2009-08-01

This project focuses upon the use of jam2jam, a generative computer system, to increase access to improvization experiences for children and to facilitate new kinds of relationships with artists. The network jamming system uses visual and audio cultural materials to enable communities to be expressive with artistic materials that they value as a community. As the system is part of a network, performances can be shared between communities at great distances and recordings of performances can be uploaded to a digital social network (http://www.jam2jam.com/) and shared both locally and with the wider community. This paper examines a preliminary project where artwork made by Indigenous mental health clients in Far North Queensland was digitized and given to a group of 8-12-year-old urban Indigenous children to 'improvize' with and make music/video clips using the jam2jam instrument. It seeks to generate a discussion and identify applications within creative arts-led community health settings to facilitate new kinds of relationships with self, peers, local community, culture and artists through collaborative improvization.

Jamming of Monodisperse Cylindrical Grains in Featureless Vertical Channels

NASA Astrophysics Data System (ADS)

Friedl, Nicholas; Baxter, G. William

2014-03-01

We study jamming of low aspect-ratio cylindrical Delrin grains falling through a featureless vertical channel under the influence of gravity. These grains have an aspect-ratio less than two (H/D < 2) and resemble aspirin tablets, 35mm film canisters, poker chips, or coins. Monodisperse grains are allowed to fall under the influence of gravity through a uniform channel of square cross-section where the channel width is greater than the grain size and constant along the length of the channel. No combination of grain heights and diameters is equal to the channel width. Collections of grains sometimes form jams, stable structures in which the grains are supported by the channel walls and not by grains or walls beneath them. The probability of a jam occurring and the jam's strength are influenced by the grain dimensions and channel width. We will present experimental measurements of the jamming probability and jam strength and discuss the relationship of these results to other experiments and theories. Supported by an Undergraduate Research Grant from Penn State Erie, The Behrend College.

Short range RF communication for jet engine control

NASA Technical Reports Server (NTRS)

Sexton, Daniel White (Inventor); Hershey, John Erik (Inventor)

2007-01-01

A method transmitting a message over at least one of a plurality of radio frequency (RF) channels of an RF communications network is provided. The method comprises the steps of detecting a presence of jamming pulses in the at least one of the plurality of RF channels. The characteristics of the jamming pulses in the at least one of the plurality of RF channels is determined wherein the determined characteristics define at least interstices between the jamming pulses. The message is transmitted over the at least one of the plurality of RF channels wherein the message is transmitted within the interstices of the jamming pulse determined from the step of determining characteristics of the jamming pulses.

JAM-A protects from thrombosis by suppressing integrin αIIbβ3-dependent outside-in signaling in platelets

PubMed Central

Naik, Meghna U.; Stalker, Timothy J.; Brass, Lawrence F.

2012-01-01

Mounting evidence suggests that agonist-initiated signaling in platelets is closely regulated to avoid excessive responses to injury. A variety of physiologic agonists induce a cascade of signaling events termed as inside-out signaling that culminate in exposure of high-affinity binding sites on integrin αIIbβ3. Once platelet activation has occurred, integrin αIIbβ3 stabilizes thrombus formation by providing agonist-independent “outside-in” signals mediated in part by contractile signaling. Junctional adhesion molecule A (JAM-A), a member of the cortical thymocyte marker of the Xenopus (CTX) family, was initially identified as a receptor for a platelet stimulatory mAb. Here we show that JAM-A in resting platelets functions as an endogenous inhibitor of platelet function. Genetic ablation of Jam-A in mice enhances thrombotic function of platelets in vivo. The absence of Jam-A results in increase in platelet aggregation ex vivo. This gain of function is not because of enhanced inside-out signaling because granular secretion, Thromboxane A2 (TxA2) generation, as well as fibrinogen receptor activation, are normal in the absence of Jam-A. Interestingly, integrin outside-in signaling such as platelet spreading and clot retraction is augmented in Jam-A–deficient platelets. We conclude that JAM-A normally limits platelet accumulation by inhibiting integrin outside-in signaling thus preventing premature platelet activation. PMID:22271446

Early Detection of Junctional Adhesion Molecule-1 (JAM-1) in the Circulation after Experimental and Clinical Polytrauma

PubMed Central

Denk, Stephanie; Wiegner, Rebecca; Hönes, Felix M.; Messerer, David A. C.; Radermacher, Peter; Kalbitz, Miriam; Braumüller, Sonja; McCook, Oscar; Gebhard, Florian; Weckbach, Sebastian; Huber-Lang, Markus

2015-01-01

Severe tissue trauma-induced systemic inflammation is often accompanied by evident or occult blood-organ barrier dysfunctions, frequently leading to multiple organ dysfunction. However, it is unknown whether specific barrier molecules are shed into the circulation early after trauma as potential indicators of an initial barrier dysfunction. The release of the barrier molecule junctional adhesion molecule-1 (JAM-1) was investigated in plasma of C57BL/6 mice 2 h after experimental mono- and polytrauma as well as in polytrauma patients (ISS ≥ 18) during a 10-day period. Correlation analyses were performed to indicate a linkage between JAM-1 plasma concentrations and organ failure. JAM-1 was systemically detected after experimental trauma in mice with blunt chest trauma as a driving force. Accordingly, JAM-1 was reduced in lung tissue after pulmonary contusion and JAM-1 plasma levels significantly correlated with increased protein levels in the bronchoalveolar lavage as a sign for alveolocapillary barrier dysfunction. Furthermore, JAM-1 was markedly released into the plasma of polytrauma patients as early as 4 h after the trauma insult and significantly correlated with severity of disease and organ dysfunction (APACHE II and SOFA score). The data support an early injury- and time-dependent appearance of the barrier molecule JAM-1 in the circulation indicative of a commencing trauma-induced barrier dysfunction. PMID:26556956

Shuttle GPS R/PA configuration and specification study

NASA Technical Reports Server (NTRS)

Booth, R. W. D.

1979-01-01

Changes in the technical specifications for a global positioning system (GPS) receiving system dedicated to space shuttle use are presented. Various hardware functions including acquisition, tracking, and measurement are emphasized. The anti-jam performance of the baseline GPS systems are evaluated. Other topics addressed include: the impact on R/PA design of the use of ground based transmitters; problems involved with the use of single channel tests sets; utility of various R/PA antenna interconnections topologies; the choice of the averaging interval for delta range measurements; and the use of interferometry techniques for the computation of orbiter attitude were undertaken.

Subarray-based FDA radar to counteract deceptive ECM signals

NASA Astrophysics Data System (ADS)

Abdalla, Ahmed; Wang, Wen-Qin; Yuan, Zhao; Mohamed, Suhad; Bin, Tang

2016-12-01

In recent years, the frequency diverse array (FDA) radar concept has attracted extensive attention, as it may benefit from a small frequency increment, compared to the carrier frequency across the array elements and thereby achieve an array factor that is a function of the angle, the time, and the range which is superior to the conventional phase array radar (PAR). However, limited effort on the subject of FDA in electronic countermeasure scenarios, especially in the presence of mainbeam deceptive jamming, has been published. Basic FDA is not desirable for anti-jamming applications, due to the range-angle coupling response of targets. In this paper, a novel method based on subarrayed FDA signal processing is proposed to counteract deceptive ECM signals. We divide the FDA array into multiple subarrays, each of which employs a distinct frequency increment. As a result, in the subarray-based FDA, the desired target can be distinguished at subarray level in joint range-angle-Doppler domain by utilizing the fact that the jammer generates false targets with the same ranges to each subarray without reparations. The performance assessment shows that the proposed solution is effective for deceptive ECM targets suppression. The effectiveness is verified by simulation results.

ADDRESSING THE DEFICIT: Updating the Budgetary Implications of Selected GAO Work

DTIC Science & Technology

1996-06-01

DGPS DI DLA DOD DOE DOT DUR EDWAA EM EPA FAIR FAA FAS FDIC FHWA FY GAO GSA HACCP HCFA HHS HMO HUD IDB IFAD INS IRS JCT...Marti, the broadcasts are constantly and effectively jammed , USIA’S research data shows that, mainly as a result of the jamming , the number of Cubans...hours (from 3:30 am to 8:00 am), but Cuban jamming also expanded. In an attempt to overcome jamming , TV Marti has plans to convert from VHF to UHF

Life Times of Simulated Traffic Jams

NASA Astrophysics Data System (ADS)

Nagel, Kai

We study a model for freeway traffic which includes strong noise taking into account the fluctuations of individual driving behavior. The model shows emergent traffic jams with a self-similar appearance near the throughput maximum of the traffic. The lifetime distribution of these jams shows a short scaling regime, which gets considerably longer if one reduces the fluctuations when driving at maximum speed but leaves the fluctuations for slowing down or accelerating unchanged. The outflow from a traffic jam self-organizes into this state of maximum throughput.

FCC press release and consumer/retailer enforcement advisories regarding cell jammers, GPS jammers, and other jamming devices

DOT National Transportation Integrated Search

2011-02-09

FCC ENFORCEMENT BUREAU STEPS UP EDUCATION AND ENFORCEMENT EFFORTS AGAINST CELLPHONE AND GPS JAMMING. CONSUMERS BEWARE: It is Unlawful to Use Cell Jammers and Other Equipment : that Blocks, Jams, or Interferes with Authorized Radio Communication...

The thermodynamics of dense granular flow and jamming

NASA Astrophysics Data System (ADS)

Lu, Shih Yu

The scope of the thesis is to propose, based on experimental evidence and theoretical validation, a quantifiable connection between systems that exhibit the jamming phenomenon. When jammed, some materials that flow are able to resist deformation so that they appear solid-like on the laboratory scale. But unlike ordinary fusion, which has a critically defined criterion in pressure and temperature, jamming occurs under a wide range of conditions. These condition have been rigorously investigated but at the moment, no self-consistent framework can apply to grains, foam and colloids that may have suddenly ceased to flow. To quantify the jamming behavior, a constitutive model of dense granular flows is deduced from shear-flow experiments. The empirical equations are then generalized, via a thermodynamic approach, into an equation-of-state for jamming. Notably, the unifying theory also predicts the experimental data on the behavior of molecular glassy liquids. This analogy paves a crucial road map for a unifying theoretical framework in condensed matter, for example, ranging from sand to fire retardants to toothpaste.

Jamming by compressing a system of granular crosses

NASA Astrophysics Data System (ADS)

Zheng, Hu; Wang, Dong; Barés, Jonathan; Behringer, Robert

2017-06-01

A disordered stress-free granular packing can be jammed, transformed into a mechanically rigid structure, by increasing the density of particles or by applying shear deformation. The jamming behavior of systems made of 2D circular discs has been investigated in detail, but very little is known about jamming for non-spherical particles, and particularly, non-convex particles. Here, we perform an experimental study on jamming by compression of a system of quasi-2D granular crosses made of photo-elastic crosses. We measure the pressure evolution during cyclic compression and decompression. The Jamming packing fraction of these quasi-2D granular crosses is ϕJ ≃ 0.475, which is much smaller than the value ϕJ ≃ 0.84 for-2D granular disks. The packing fraction shifts systematically to higher values under compressive cycling, corresponding to systematic shifts in the stress-strain response curves. Associated with these shifts are rotations of the crosses, with minimal changes in their centers of mass.

Phase transitions in traffic flow on multilane roads.

PubMed

Kerner, Boris S; Klenov, Sergey L

2009-11-01

Based on empirical and numerical analyses of vehicular traffic, the physics of spatiotemporal phase transitions in traffic flow on multilane roads is revealed. The complex dynamics of moving jams observed in single vehicle data measured by video cameras on American highways is explained by the nucleation-interruption effect in synchronized flow, i.e., the spontaneous nucleation of a narrow moving jam with the subsequent jam dissolution. We find that (i) lane changing, vehicle merging from on-ramps, and vehicle leaving to off-ramps result in different traffic phases-free flow, synchronized flow, and wide moving jams-occurring and coexisting in different road lanes as well as in diverse phase transitions between the traffic phases; (ii) in synchronized flow, the phase transitions are responsible for a non-regular moving jam dynamics that explains measured single vehicle data: moving jams emerge and dissolve randomly at various road locations in different lanes; (iii) the phase transitions result also in diverse expanded general congested patterns occurring at closely located bottlenecks.

Nonuniversality of density and disorder in jammed sphere packings

NASA Astrophysics Data System (ADS)

Jiao, Yang; Stillinger, Frank H.; Torquato, Salvatore

2011-01-01

We show for the first time that collectively jammed disordered packings of three-dimensional monodisperse frictionless hard spheres can be produced and tuned using a novel numerical protocol with packing density ϕ as low as 0.6. This is well below the value of 0.64 associated with the maximally random jammed state and entirely unrelated to the ill-defined "random loose packing" state density. Specifically, collectively jammed packings are generated with a very narrow distribution centered at any density ϕ over a wide density range ϕ ɛ(0.6,0.740 48…) with variable disorder. Our results support the view that there is no universal jamming point that is distinguishable based on the packing density and frequency of occurrence. Our jammed packings are mapped onto a density-order-metric plane, which provides a broader characterization of packings than density alone. Other packing characteristics, such as the pair correlation function, average contact number, and fraction of rattlers are quantified and discussed.

Research on the laser angle deception jamming technology of laser countermeasure

NASA Astrophysics Data System (ADS)

Ma, Shi-wei; Chen, Wen-jian; Gao, Wei; Duan, Yuan-yuan

2015-10-01

In recent years , laser guided weapons behave very well at destroying the military goals in the local wars, the single-shot probability, effective range and hitting precision getting better. And the semi-active laser guided weapons are the most widely used laser guided weapons. In order to improve the viability and protect important military goals, it's necessary to study the technology to against the semi-active guided weapons. This paper studies the working principle, the advantages and disadvantages of the semi-active guided weapons at first, and analyze the possibility of laser angle deception jamming system working. Then it analyzes the working principle and process of laser angle deception jamming technology. Finally it designs a half-real simulation system of laser angle deception jamming, which consists of semi-active laser guided weapons simulation system and laser angle deception jamming system. The simulation system demonstrates the working process of the laser angle deception jamming system. This paper provides fundamental base for the research on the countermeasure technology of semi-active laser guided weapons.

Shape effects on time-scale divergence at athermal jamming transition of frictionless non-spherical particles

NASA Astrophysics Data System (ADS)

Yuan, Ye; Jin, Weiwei; Liu, Lufeng; Li, Shuixiang

2017-10-01

The critical behaviors of a granular system at the jamming transition have been extensively studied from both mechanical and thermodynamic perspectives. In this work, we numerically investigate the jamming behaviors of a variety of frictionless non-spherical particles, including spherocylinder, ellipsoid, spherotetrahedron and spherocube. In particular, for a given particle shape, a series of random configurations at different fixed densities are generated and relaxed to minimize interparticle overlaps using the relaxation algorithm. We find that as the jamming point (i.e., point J) is approached, the number of iteration steps (defined as the "time-scale" for our systems) required to completely relax the interparticle overlaps exhibits a clear power-law divergence. The dependence of the detailed mathematical form of the power-law divergence on particle shapes is systematically investigated and elucidated, which suggests that the shape effects can be generally categorized as elongation and roundness. Importantly, we show the jamming transition density can be accurately determined from the analysis of time-scale divergence for different non-spherical shapes, and the obtained values agree very well with corresponding ones reported in literature. Moreover, we study the plastic behaviors of over-jammed packings of different particles under a compression-expansion procedure and find that the jamming of ellipsoid is much more robust than other non-spherical particles. This work offers an alternative approximate procedure besides conventional packing algorithms for studying athermal jamming transition in granular system of frictionless non-spherical particles.

Preparation of resveratrol-enriched grape juice from ultrasonication treated grape fruits.

PubMed

Hasan, Md Mohidul; Yun, Hae-Keun; Kwak, Eun-Jung; Baek, Kwang-Hyun

2014-03-01

Grape (Vitis spp.) is a major source of resveratrol that can be eaten directly or after making jam, jelly, wine and juice. Resveratrol (3,5,4'-trihydroxystilbene) has a profound positive influence on human health, including anti-carcinogenic, anti-cancer, anti-inflammatory, and anti-ageing effects and the ability to lower blood sugar. During industrial production of grape juice, resveratrol is lost because of the use of clarifying agents and filtration; therefore, commercial grape juice contains very low amounts of resveratrol. In this study, we investigated the accumulation of resveratrol in grape juice prepared from three varieties of grape, viz. Campbell Early, Muscat Bailey A (MBA) and Kyoho, following post-harvest ultrasonication cleaning for 5 min and 6h of incubation in the dark at 25 °C. This process resulted in the amounts of resveratrol increasing by 1.53, 1.15 and 1.24 times in juice prepared from Campbell Early, MBA and Kyoho, respectively, without changing the amounts of total soluble solids. Overall, our results indicate that ultrasonication treatment of post-harvested grape fruits can be an effective method for producing resveratrol-enriched grape juice as well as cleaning grapes thoroughly. Copyright © 2013 Elsevier B.V. All rights reserved.

Jamming and Learning: Analysing Changing Collective Practice of Changing Participation

ERIC Educational Resources Information Center

Brinck, Lars

2017-01-01

This article reports a long-term ethnographic study on jamming and learning from an entwined artistic and educational perspective. The study investigates aspects of learning during a professional band's jamming and recording eight groove-jazz frameworks and a series of subsequent concerts with pre-academy students "sitting in." Fieldwork…

Topology-selective jamming of fully-connected, code-division random-access networks

NASA Technical Reports Server (NTRS)

Polydoros, Andreas; Cheng, Unjeng

1990-01-01

The purpose is to introduce certain models of topology selective stochastic jamming and examine its impact on a class of fully-connected, spread-spectrum, slotted ALOHA-type random access networks. The theory covers dedicated as well as half-duplex units. The dominant role of the spatial duty factor is established, and connections with the dual concept of time selective jamming are discussed. The optimal choices of coding rate and link access parameters (from the users' side) and the jamming spatial fraction are numerically established for DS and FH spreading.

Aircraft Loss-of-Control Accident Prevention: Switching Control of the GTM Aircraft with Elevator Jam Failures

NASA Technical Reports Server (NTRS)

Chang, Bor-Chin; Kwatny, Harry G.; Belcastro, Christine; Belcastro, Celeste

2008-01-01

Switching control, servomechanism, and H2 control theory are used to provide a practical and easy-to-implement solution for the actuator jam problem. A jammed actuator not only causes a reduction of control authority, but also creates a persistent disturbance with uncertain amplitude. The longitudinal dynamics model of the NASA GTM UAV is employed to demonstrate that a single fixed reconfigured controller design based on the proposed approach is capable of accommodating an elevator jam failure with arbitrary jam position as long as the thrust control has enough control authority. This paper is a first step towards solving a more comprehensive in-flight loss-of-control accident prevention problem that involves multiple actuator failures, structure damages, unanticipated faults, and nonlinear upset regime recovery, etc.

Diffusion in jammed particle packs

NASA Astrophysics Data System (ADS)

Bolintineanu, Dan S.; Silbert, Leonardo E.; Grest, Gary S.; Lechman, Jeremy B.

2015-03-01

Diffusive transport in jammed particle packs is of interest for a number of applications, as well as being a potential indicator of structural properties near the jamming point. To this end, we report stochastic simulations of equilibrium diffusion through monodisperse sphere packs near the jamming point in the limit of a perfectly insulating surrounding medium. The time dependence of various diffusion properties is resolved over several orders of magnitude. Two time regimes of expected Fickian diffusion are observed, separated by an intermediate regime of anomalous diffusion. This intermediate regime grows as the particle volume fraction approaches the critical jamming transition. The diffusion behavior is fully controlled by the extent of the contacts between neighboring particles, which in turn depend on proximity to the jamming point. In particular, the mean first passage time associated with the escape of random walkers between neighboring particles is shown to control both the time to recover Fickian diffusion and the long time diffusivity. Scaling laws are established that relate these quantities to the difference between the actual and critical jamming volume fractions. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's NNSA under Contract DE- AC04-94AL85000.

Jamming transitions induced by an attraction in pedestrian flow.

PubMed

Kwak, Jaeyoung; Jo, Hang-Hyun; Luttinen, Tapio; Kosonen, Iisakki

2017-08-01

We numerically study jamming transitions in pedestrian flow interacting with an attraction, mostly based on the social force model for pedestrians who can join the attraction. We formulate the joining probability as a function of social influence from others, reflecting that individual choice behavior is likely influenced by others. By controlling pedestrian influx and the social influence parameter, we identify various pedestrian flow patterns. For the bidirectional flow scenario, we observe a transition from the free flow phase to the freezing phase, in which oppositely walking pedestrians reach a complete stop and block each other. On the other hand, a different transition behavior appears in the unidirectional flow scenario, i.e., from the free flow phase to the localized jam phase and then to the extended jam phase. It is also observed that the extended jam phase can end up in freezing phenomena with a certain probability when pedestrian flux is high with strong social influence. This study highlights that attractive interactions between pedestrians and an attraction can trigger jamming transitions by increasing the number of conflicts among pedestrians near the attraction. In order to avoid excessive pedestrian jams, we suggest suppressing the number of conflicts under a certain level by moderating pedestrian influx especially when the social influence is strong.

Jamming transitions induced by an attraction in pedestrian flow

NASA Astrophysics Data System (ADS)

Kwak, Jaeyoung; Jo, Hang-Hyun; Luttinen, Tapio; Kosonen, Iisakki

2017-08-01

We numerically study jamming transitions in pedestrian flow interacting with an attraction, mostly based on the social force model for pedestrians who can join the attraction. We formulate the joining probability as a function of social influence from others, reflecting that individual choice behavior is likely influenced by others. By controlling pedestrian influx and the social influence parameter, we identify various pedestrian flow patterns. For the bidirectional flow scenario, we observe a transition from the free flow phase to the freezing phase, in which oppositely walking pedestrians reach a complete stop and block each other. On the other hand, a different transition behavior appears in the unidirectional flow scenario, i.e., from the free flow phase to the localized jam phase and then to the extended jam phase. It is also observed that the extended jam phase can end up in freezing phenomena with a certain probability when pedestrian flux is high with strong social influence. This study highlights that attractive interactions between pedestrians and an attraction can trigger jamming transitions by increasing the number of conflicts among pedestrians near the attraction. In order to avoid excessive pedestrian jams, we suggest suppressing the number of conflicts under a certain level by moderating pedestrian influx especially when the social influence is strong.

Effect of xantham gum, steviosides, clove, and cinnamon essential oils on the sensory and microbiological quality of a low sugar tomato jam.

PubMed

Gliemmo, María F; Montagnani, María A; Schelegueda, Laura I; González, Malena M; Campos, Carmen A

2016-03-01

The partial or total decrease of sugar content in the formulation of jams affects their physical, chemical and microbiological stability. In order to minimize these technological problems, we studied the effect of xanthan gum (XG), steviosides, cinnamon (CO), and clove (CLO) essential oils on the sensory and microbiological quality of a low sugar tomato jam. Levels of 0.250 g/100 g steviosides and 0.450 g/100 g XG showed maximum score of overall acceptability of jam. The combination of essential oils produced synergistic and additive effects in vitro on growth of Z. bailii and Z. rouxii, respectively. However, in the jam, CO was more effective and CLO did not modify the CO action. Cell surface was one of the sites of action of CO since a decrease in yeast cell surface hydrophobicity was observed. From the microbiological and sensory points of view, 0.0060 g/100 g CO showed the maximum score of jam overall acceptability and did not cause yeast inactivation but it could be useful as an additional stress factor against yeast post--process contamination. The adequate levels of XG, steviosides, and CO can improve the quality of a low sugar jam formulation. © The Author(s) 2015.

Analysis of the development of missile-borne IR imaging detecting technologies

NASA Astrophysics Data System (ADS)

Fan, Jinxiang; Wang, Feng

2017-10-01

Today's infrared imaging guiding missiles are facing many challenges. With the development of targets' stealth, new-style IR countermeasures and penetrating technologies as well as the complexity of the operational environments, infrared imaging guiding missiles must meet the higher requirements of efficient target detection, capability of anti-interference and anti-jamming and the operational adaptability in complex, dynamic operating environments. Missileborne infrared imaging detecting systems are constrained by practical considerations like cost, size, weight and power (SWaP), and lifecycle requirements. Future-generation infrared imaging guiding missiles need to be resilient to changing operating environments and capable of doing more with fewer resources. Advanced IR imaging detecting and information exploring technologies are the key technologies that affect the future direction of IR imaging guidance missiles. Infrared imaging detecting and information exploring technologies research will support the development of more robust and efficient missile-borne infrared imaging detecting systems. Novelty IR imaging technologies, such as Infrared adaptive spectral imaging, are the key to effectively detect, recognize and track target under the complicated operating and countermeasures environments. Innovative information exploring techniques for the information of target, background and countermeasures provided by the detection system is the base for missile to recognize target and counter interference, jamming and countermeasure. Modular hardware and software development is the enabler for implementing multi-purpose, multi-function solutions. Uncooled IRFPA detectors and High-operating temperature IRFPA detectors as well as commercial-off-the-shelf (COTS) technology will support the implementing of low-cost infrared imaging guiding missiles. In this paper, the current status and features of missile-borne IR imaging detecting technologies are summarized. The key technologies and its development trends of missiles' IR imaging detecting technologies are analyzed.

Shear jamming: where does it come from and how is it affected by particle properties?

NASA Astrophysics Data System (ADS)

Wang, Dong

Granular systems have been shown to be able to behave like solids, under shear, even when their densities are below the critical packing fraction for frictionless isotropic jamming. To understand such a phenomena, called shear jamming, the questions we address here is: how does shear bring a system from a unjammed state to a jammed state and how do particle properties, such as inter-particle friction and particle shape, affect shear jamming? Since Z can be used to distinguish jammed states from unjammed ones (Z = 3 is the isotropic jamming point for 2 D frictional disks), it is vital to understand how shear increases Z. In the first part of this talk, we propose a set of three particles in contact, denoted as a trimer, as the basic unit to microscopically characterize the deformation of the system. Trimers, stabilized by inter-grain friction, are then expected to bend in response to shear to make extra contacts to regain stability. By defining a projection operator of the opening angle of the trimer to the compression direction in the shear, O, we see a systematically linear decrease of this quantity with respect to shear strain, demonstrating the bending of trimers as expected. In the second part of this talk, we look into the effect of particle properties on shear jamming. Photoelastic disks either wrapped with Teflon to reduce friction or with fine teeth on the edge to increase friction are used to study the effect of friction. In addition, disks are replaced with ellipses to introduce anisotropy into the particle shape. Shear jamming is observed for all the cases. For the disk system, the lowest packing fraction that can reach a shear jammed state increases with friction. For the ellipse system, shear brings the system to a more ordered state and particles tend to align to a certain angle relative to the principal directions of shear, regardless of packing fraction. Support by NSF DMR1206351, NASA NNX15AD38G, the W. M. Keck Foundation and a Triangle MRSEC fellowship is greatly appreciated.

Combined osmodehydration and high pressure processing on the enzyme stability and antioxidant capacity of a grapefruit jam

USDA-ARS?s Scientific Manuscript database

A combined osmodehydration process and high pressure treatment (OD-HHP) was developed for grapefruit jam preservation. The inactivation kinetics of pectinmethylesterase (PME) and peroxidase (POD) in the osmodehydrated (OD) jam treated by combined thermal (45-75°C) and high pressure (550–700 MPa) pro...

V-22 Osprey Joint Services Advanced Vertical Lift Aircraft (V-22)

DTIC Science & Technology

2015-12-01

Be Determined TY - Then Year UCR - Unit Cost Reporting U.S. - United States USD(AT&L) - Under Secretary of Defense (Acquisition, Technology and...Rotor Operational Enviroment DECM SIRFC w/RF Jamming DIRCM SIRFC w/RF Jamming DIRCM SIRFC w/RWR, MW, CMDS SIRFC w/RF, Jamming DIRCM SIRFC w/RF

Effect of substituted gelling agents from pomegranate peel on colour, textural and sensory properties of pomegranate jam.

PubMed

Abid, Mouna; Yaich, Héla; Hidouri, Hayfa; Attia, Hamadi; Ayadi, M A

2018-01-15

A series of pomegranate jams were prepared from a Tunisian ecotype (Tounsi) with different amounts of sugar (10, 20 and 30%) and low-methoxylated pectin (0.2, 0.7 and 1.2%). The most appreciated formulation was that contaning 30% sugars and 0.2% pectin. Then, commercial pectin was substituted by other gelling agents (pomegranate peel powders dried at 50°C vs lyophilized, pectin and fibre extracted from pomegranate peel) for the preparation of pomegranate peel-based jams. The elaborated jams were evaluated for physichochemical, colour, texture and sensory characteristics. Results revealed that the jam (JPP2) elaborated with 0.2% pectin extracted from pomegranate peel exhibited similar overall acceptability to that prepared with commercial pectin. However, it was more acceptable than other pomegranate peel-based jams, which was related to a better appreciation of sweetness and colour. According to the colour and texture measurements, this sample (JPP2) was more reddish and less firm than other samples. Copyright © 2017 Elsevier Ltd. All rights reserved.

Programming jammed Codman Hakim programmable valves: study of an explanted valve and successful programming in a patient.

PubMed

Wong, Sui-To; Wen, Eleanor; Fong, Dawson

2013-08-01

Malfunction of a Codman Hakim programmable valve due to jamming of its programmable component may necessitate shunt revision. The authors report a method for programming jammed Codman Hakim programmable valves by using a Strata II magnet and additional neodymium magnets. The programming method was derived after studying a jammed valve in the laboratory that was explanted from an 10-year-old boy with a history of fourth ventricle ependymoma. Programming the explanted valve with a Codman programmer failed, but rotating a Strata II magnet above the valve resulted in rotation of the spiral cam in the valve. It was found that the Strata II magnet could be used to program the jammed valve by rotating the magnet 90° or multiples of 90° above the valve. The strength of the magnetic field of the Strata II magnet was able to be increased by putting neodymium magnets on it. The programming method was then successfully used in a patient with a jammed Codman Hakim programmable valve. After successful programming using this method, clinical and radiological follow-up of the patient was advised.

Characteristics of physico-chemical properties of bilberry (Vaccinium myrtillus L.) jams with added herbs.

PubMed

Korus, Anna; Jaworska, Grażyna; Bernaś, Emilia; Juszczak, Lesław

2015-05-01

Low-sugar bilberry jams without added herbs and those with added mentha (1 %) and lemon balm (1 %) were examined for levels of selected physico-chemical indicators, antioxidant activity, colour and texture. Jams were obtained by two methods: cooked in an open pan and cooked in a vacuum evaporator. 100 g fresh mass contained 0.076-0.481 mg HMF, 5.8-7.1 mg vitamin C, 176-232 mg total polyphenols, 122-156 mg total flavonoids, 73-96 mg total anthocyanins, with antioxidant activity per 1 g of 405-575 μM Trolox (ABTS), 71-89 μM Trolox (DPPH) and 120-176 μM Fe(2+) (FRAP). Jams cooked in a vacuum evaporator had higher levels of the indicators examined, better colour and worse texture. Jams with added herbs generally showed higher levels of all indicators, but their colour and texture were slightly worse. Storing jams for 8 months caused a reduction in antioxidant constituents of 7-20 % along with a deterioration of colour and texture.

Visual traffic jam analysis based on trajectory data.

PubMed

Wang, Zuchao; Lu, Min; Yuan, Xiaoru; Zhang, Junping; van de Wetering, Huub

2013-12-01

In this work, we present an interactive system for visual analysis of urban traffic congestion based on GPS trajectories. For these trajectories we develop strategies to extract and derive traffic jam information. After cleaning the trajectories, they are matched to a road network. Subsequently, traffic speed on each road segment is computed and traffic jam events are automatically detected. Spatially and temporally related events are concatenated in, so-called, traffic jam propagation graphs. These graphs form a high-level description of a traffic jam and its propagation in time and space. Our system provides multiple views for visually exploring and analyzing the traffic condition of a large city as a whole, on the level of propagation graphs, and on road segment level. Case studies with 24 days of taxi GPS trajectories collected in Beijing demonstrate the effectiveness of our system.

Phenolic profiles of raw apricots, pumpkins, and their purees in the evaluation of apricot nectar and jam authenticity.

PubMed

Dragovic-Uzelac, Verica; Delonga, Karmela; Levaj, Branka; Djakovic, Senka; Pospisil, Jasna

2005-06-15

The possibility of proving the undeclared addition of pumpkin puree in apricot nectars and jams has been investigated by using the phenol compound fingerprint and sensory evaluation. The cheaper pumpkin admixtures in apricot nectars and jams could not be detected by the sensory evaluation, particularly if present in quantities of <15%. The lower admixtures of pumpkin puree in apricot nectars and jams could be detected by the presence of syringic acid, a phenolic compound characteristic of the investigated pumpkins (Cucurbita pepo cv. Gleisdorff and Table Gold, Cucurbita maxima cv. Turkinja, and Cucurbita moschata cv. Argenta). Syringic acid was isolated from pumpkin puree and determined by using HPLC with diode array detection. By using the phenolic profile, undeclared pumpkin admixture (> or =5%) in the apricot nectars and jams could be proven.

A Jamming Phase Diagram for Pressing Polymers

NASA Astrophysics Data System (ADS)

Teng, Chao; Zhang, Zexin; Wang, Xiaoliang; Xue, Gi; Nanjing University Team; Soochow University Collaboration

2011-03-01

Molecular glasses begin to flow when they are heated. Other glassy systems, such as dense foams, emulsions, colloidal suspensions and granular materials, begin to flow when subjected to sufficiently large stresses. The equivalence of these two routes to flow is a basic tenet of jamming, a conceptual means of unifying glassy behavior in a swath of disordered, dynamical arrested systems. However, a full understanding of jamming transition for polymers remains elusive. By controlling the packing densities of polymer glasses, we found that polymer glasses could once flow under cold-pressing at temperatures well below its calorimetric glass transition temperature (Tg). The thermomechanical analysis (TMA) results confirmed that Tg changed with density as well as the applied stress, which is exactly what to be expected within the jamming picture. We propose a jamming phase diagram for polymers based on our laboratory experiments.

Effect of friction on shear jamming

NASA Astrophysics Data System (ADS)

Wang, Dong; Ren, Jie; Dijksman, Joshua; Behringer, Robert

2014-03-01

Shear Jamming of granular materials was first found for systems of frictional disks, with a static friction coefficients μs ~= 0 . 6 . Jamming by shear is obtained by starting from a zero-stress state with a packing fraction ϕS <= ϕ <=ϕJ between ϕJ (isotropic jamming) and a lowest ϕS for shear jamming. This phenomenon is associated with strong anisotropy in stress and the contact network in the form of ``force chains,'' which are stabilized and/or enhanced by the presence of friction. We address experimentally how reducing friction affects shear jamming by using either teflon disks of teflon wrapped photoelastic particles. The teflon disks were placed in a wall driven 2D shear apparatus, in which we can probe shear stresses mechanically. Teflon-wrapped disks were placed in a bottom driven 2D shear apparatus (Ren et al., PRL 2013). Both apparatuses provide uniform simple shear. In all low- μ experiments, the shear jamming occurred, as observed through stress increases on the packing. However, the low- μ differences observed for ϕJ -ϕS were smaller than for higher friction particles. Ongoing work is studying systems using hydrogel disks, which have a lower friction coefficient than teflon. We acknowledge support from NSF Grant No. DMR12-06351, ARO Grant No. W911NF-1-11-0110, and NASA Grant No. NNX10AU01G.

Effect of friction on shear jamming

NASA Astrophysics Data System (ADS)

Wang, Dong; Ren, Jie; Dijksman, Joshua; Behringer, Robert

2014-11-01

Shear Jamming of granular materials was first found for systems of frictional disks, with a static friction coefficients μs ~= 0 . 6 . Jamming by shear is obtained by starting from a zero-stress state with a packing fraction ϕS <= ϕ <=ϕJ between ϕJ (isotropic jamming) and a lowest ϕS for shear jamming. This phenomenon is associated with strong anisotropy in stress and the contact network in the form of ``force chains,'' which are stabilized and/or enhanced by the presence of friction. The issue that we address experimentally is how reducing friction affects shear jamming. We use photoelastic disks that have been wrapped with Teflon, lowering the friction coefficient substantially from previous experiments. The Teflon-wrapped disks were placed in a well-studied 2D shear apparatus (Ren et al., PRL, 110, 018302 (2013)), which provides uniform simple shear without generating shear bands. Shear jamming is still observed, but the difference ϕJ -ϕS is smaller than for higher friction particles. With Teflon-wrapped disks, we observe larger anisotropies compared to the previous experiment with higher friction particles at the same packing fraction, which indicates force chains tending to be straight in the low friction system. We acknowledge support from NSF Grant No. DMR12-06351, ARO Grant No. W911NF-1-11-0110, and NASA Grant No. NNX10AU01G.

Origins of Shear Jamming for Frictional Grains

NASA Astrophysics Data System (ADS)

Wang, Dong; Zheng, Hu; Ren, Jie; Dijksman, Joshua; Bares, Jonathan; Behringer, Robert

2016-11-01

Granular systems have been shown to be able to behave like solids, under shear, even when their densities are below the critical packing fraction for frictionless isotropic jamming. To understand such a phenomena, called shear jamming, the question we address here is: how does shear bring a system from a unjammed state to a jammed state, where the coordination number, Z, is no less than 3, the isotropic jamming point for frictional grains? Since Z can be used to distinguish jammed states from unjammed ones, it is vital to understand how shear increases Z. We here propose a set of three particles in contact, denoted as a trimer, as the basic unit to characterize the deformation of the system. Trimers, stabilized by inter-grain friction, fail under a certain amount of shear and bend to make extra contacts to regain stability. By defining a projection operator of the opening angle of the trimer to the compression direction in the shear, O, we see a systematically linear decrease of this quantity with respect to shear strain, demonstrating the bending of trimers as expected. In addition, the average change of O from one shear step to the next shows a good collapse when plotted against Z, indicating a universal behavior in the process of shear jamming. We acknowledge support from NSF DMR1206351, NASA NNX15AD38G, the William M. Keck Foundation and a RT-MRSEC Fellowship.

21 CFR 150.160 - Fruit preserves and jams.

Code of Federal Regulations, 2014 CFR

2014-04-01

... jams. (a) The preserves or jams for which definitions and standards of identity are prescribed by this... combination of two, three, four, or five of such fruits in which the weight of each is not less than one-fifth... of the weight of the combination. (ii) Any combination of apple and one, two, three, or four of such...

75 FR 43395 - Airworthiness Directives; Aircraft Industries a.s. Model L 23 Super Blanik Gliders

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-26

... elevator in place and in jamming of the Pilot's elevator control system, and subsequent loss of elevator... elevator in place and in jamming of the Pilot's elevator control system, and subsequent loss of elevator... retaining the elevator in place and in jamming of the Pilot's elevator control system, and subsequent loss...

Situk River Hydrology Following Closure of Russell Fiord by Hubbard Glacier

DTIC Science & Technology

2011-03-01

and in- vestigate potential channel erosion, the impacts on the Old Situk River crossing and Situk Lake, and the potential influence of log jams and...52 Log jams ...crossing and Situk Lake (the upstream source of the Situk River), and the potential impacts of log jams and channel migration. ERDC/CRREL TR-11-5 4 2

Implementation of LSCMA adaptive array terminal for mobile satellite communications

NASA Astrophysics Data System (ADS)

Zhou, Shun; Wang, Huali; Xu, Zhijun

2007-11-01

This paper considers the application of adaptive array antenna based on the least squares constant modulus algorithm (LSCMA) for interference rejection in mobile SATCOM terminals. A two-element adaptive array scheme is implemented with a combination of ADI TS201S DSP chips and Altera Stratix II FPGA device, which makes a cooperating computation for adaptive beamforming. Its interference suppressing performance is verified via Matlab simulations. Digital hardware system is implemented to execute the operations of LSCMA beamforming algorithm that is represented by an algorithm flowchart. The result of simulations and test indicate that this scheme can improve the anti-jamming performance of terminals.

Non-Static error tracking control for near space airship loading platform

NASA Astrophysics Data System (ADS)

Ni, Ming; Tao, Fei; Yang, Jiandong

2018-01-01

A control scheme based on internal model with non-static error is presented against the uncertainty of the near space airship loading platform system. The uncertainty in the tracking table is represented as interval variations in stability and control derivatives. By formulating the tracking problem of the uncertainty system as a robust state feedback stabilization problem of an augmented system, sufficient condition for the existence of robust tracking controller is derived in the form of linear matrix inequality (LMI). Finally, simulation results show that the new method not only has better anti-jamming performance, but also improves the dynamic performance of the high-order systems.

A Novel Friendly Jamming Scheme in Industrial Crowdsensing Networks against Eavesdropping Attack.

PubMed

Li, Xuran; Wang, Qiu; Dai, Hong-Ning; Wang, Hao

2018-06-14

Eavesdropping attack is one of the most serious threats in industrial crowdsensing networks. In this paper, we propose a novel anti-eavesdropping scheme by introducing friendly jammers to an industrial crowdsensing network. In particular, we establish a theoretical framework considering both the probability of eavesdropping attacks and the probability of successful transmission to evaluate the effectiveness of our scheme. Our framework takes into account various channel conditions such as path loss, Rayleigh fading, and the antenna type of friendly jammers. Our results show that using jammers in industrial crowdsensing networks can effectively reduce the eavesdropping risk while having no significant influence on legitimate communications.

Denitrifying metabolism of the methylotrophic marine bacterium Methylophaga nitratireducenticrescens strain JAM1.

PubMed

Mauffrey, Florian; Cucaita, Alexandra; Constant, Philippe; Villemur, Richard

2017-01-01

Methylophaga nitratireducenticrescens strain JAM1 is a methylotrophic, marine bacterium that was isolated from a denitrification reactor treating a closed-circuit seawater aquarium. It can sustain growth under anoxic conditions by reducing nitrate ([Formula: see text]) to nitrite ([Formula: see text]). These physiological traits are attributed to gene clusters that encode two dissimilatory nitrate reductases (Nar). Strain JAM1 also contains gene clusters encoding two nitric oxide (NO) reductases and one nitrous oxide (N 2 O) reductase, suggesting that NO and N 2 O can be reduced by strain JAM1. Here we characterized further the denitrifying activities of M. nitratireducenticrescens JAM1. Series of oxic and anoxic cultures of strain JAM1 were performed with N 2 O, [Formula: see text] or sodium nitroprusside, and growth and N 2 O, [Formula: see text], [Formula: see text] and N 2 concentrations were measured. Ammonium ([Formula: see text])-free cultures were also tested to assess the dynamics of N 2 O, [Formula: see text] and [Formula: see text]. Isotopic labeling of N 2 O was performed in 15 NH 4 + -amended cultures. Cultures with the JAM1Δ narG1narG2 double mutant were performed to assess the involvement of the Nar systems on N 2 O production. Finally, RT-qPCR was used to measure the gene expression levels of the denitrification genes cytochrome bc -type nitric oxide reductase ( cnorB1 and cnorB2 ) and nitrous oxide reductase ( nosZ ), and also nnrS and norR that encode NO-sensitive regulators. Strain JAM1 can reduce NO to N 2 O and N 2 O to N 2 and can sustain growth under anoxic conditions by reducing N 2 O as the sole electron acceptor. Although strain JAM1 lacks a gene encoding a dissimilatory [Formula: see text] reductase, [Formula: see text]-amended cultures produce N 2 O, representing up to 6% of the N-input. [Formula: see text] was shown to be the key intermediate of this production process. Upregulation in the expression of c norB1 , cnorB2, nnrS and norR during the growth and the N 2 O accumulation phases suggests NO production in strain JAM1 cultures. By showing that all the three denitrification reductases are active, this demonstrates that M. nitratireducenticrescens JAM1 is one of many bacteria species that maintain genes associated primarily with denitrification, but not necessarily related to the maintenance of the entire pathway. The reason to maintain such an incomplete pathway could be related to the specific role of strain JAM1 in the denitrifying biofilm of the denitrification reactor from which it originates. The production of N 2 O in strain JAM1 did not involve Nar, contrary to what was demonstrated in Escherichia coli . M. nitratireducenticrescens JAM1 is the only reported Methylophaga species that has the capacity to grow under anoxic conditions by using [Formula: see text] and N 2 O as sole electron acceptors for its growth. It is also one of a few marine methylotrophs that is studied at the physiological and genetic levels in relation to its capacity to perform denitrifying activities.

Robust multiple frequency multiple power localization schemes in the presence of multiple jamming attacks

PubMed Central

2017-01-01

Localization of the wireless sensor network is a vital area acquiring an impressive research concern and called upon to expand more with the rising of its applications. As localization is gaining prominence in wireless sensor network, it is vulnerable to jamming attacks. Jamming attacks disrupt communication opportunity among the sender and receiver and deeply impact the localization process, leading to a huge error of the estimated sensor node position. Therefore, detection and elimination of jamming influence are absolutely indispensable. Range-based techniques especially Received Signal Strength (RSS) is facing severe impact of these attacks. This paper proposes algorithms based on Combination Multiple Frequency Multiple Power Localization (C-MFMPL) and Step Function Multiple Frequency Multiple Power Localization (SF-MFMPL). The algorithms have been tested in the presence of multiple types of jamming attacks including capture and replay, random and constant jammers over a log normal shadow fading propagation model. In order to overcome the impact of random and constant jammers, the proposed method uses two sets of frequencies shared by the implemented anchor nodes to obtain the averaged RSS readings all over the transmitted frequencies successfully. In addition, three stages of filters have been used to cope with the replayed beacons caused by the capture and replay jammers. In this paper the localization performance of the proposed algorithms for the ideal case which is defined by without the existence of the jamming attack are compared with the case of jamming attacks. The main contribution of this paper is to achieve robust localization performance in the presence of multiple jamming attacks under log normal shadow fading environment with a different simulation conditions and scenarios. PMID:28493977

Study of jamming of the frequency modulation infrared seekers

NASA Astrophysics Data System (ADS)

Qian, Fang; Guo, Jin; Shao, Jun-feng; Wang, Ting-feng

2013-09-01

The threat of the IR guidance missile is a direct consequence of extensive proliferation of the airborne IR countermeasure. The aim of a countermeasure system is to inject false information into a sensor system to create confusion. Many optical seekers have a single detector that is used to sense the position of its victim in its field of view. A seeker has a spinning reticle in the focal plane of the optical system that collects energy from the thermal scene and focuses it on to the detector. In this paper, the principle of the conical-scan FM reticle is analyzed. Then the effect that different amplitude or frequency modulated mid-infrared laser pulse acts on the reticle system is simulated. When the ratio of jamming energy to target radiation (repression) gradually increases, the azimuth error and the misalignment angle error become larger. The results show that simply increasing the intensity of the jamming light achieves little, but it increases the received signal strength of the FM reticle system ,so that the target will be more easily exposed. A slow variation of amplitude will warp the azimuth information received by the seeker, but the target can't be completely out of the missile tracking. If the repression and the jamming frequency change at the same time, the jamming effects can be more obvious. When the jamming signal's angular frequency is twice as large as the carrier frequency of the reticle system, the seeker will can't receive an accurate signal and the jamming can be achieved. The jamming mechanism of the conical-scan FM IR seeker is described and it is helpful to the airborne IR countermeasure system.

A thermodynamic unification of jamming

NASA Astrophysics Data System (ADS)

Lu, Kevin; Brodsky, E. E.; Kavehpour, H. P.

2008-05-01

Fragile materials ranging from sand to fire retardant to toothpaste are able to exhibit both solid and fluid-like properties across the jamming transition. Unlike ordinary fusion, systems of grains, foams and colloids jam and cease to flow under conditions that still remain unknown. Here, we quantify jamming using a thermodynamic approach by accounting for the structural ageing and the shear-induced compressibility of dry sand. Specifically, the jamming threshold is defined using a non-thermal temperature that measures the `fluffiness' of a granular mixture. The thermodynamic model, cast in terms of pressure, temperature and free volume, also successfully predicts the entropic data of five molecular glasses. Notably, the predicted configurational entropy averts the Kauzmann paradox-an unresolved crisis where the configurational entropy becomes negative-entirely. Without any free parameters, the proposed equation-of-state also governs the mechanism of shear banding and the associated features of shear softening and thickness invariance.

Developing a vacuum cooking equipment prototype to produce strawberry jam and optimization of vacuum cooking conditions.

PubMed

Okut, Dilara; Devseren, Esra; Koç, Mehmet; Ocak, Özgül Özdestan; Karataş, Haluk; Kaymak-Ertekin, Figen

2018-01-01

Purpose of this study was to develop prototype cooking equipment that can work at reduced pressure and to evaluate its performance for production of strawberry jam. The effect of vacuum cooking conditions on color soluble solid content, reducing sugars total sugars HMF and sensory properties were investigated. Also, the optimum vacuum cooking conditions for strawberry jam were optimized for Composite Rotatable Design. The optimum cooking temperature and time were determined targeting maximum soluble solid content and sensory attributes (consistency) and minimum Hue value and HMF content. The optimum vacuum cooking conditions determined were 74.4 °C temperature and 19.8 time. The soluble solid content strawberry jam made by vacuum process were similar to those prepared by traditional method. HMF contents of jams produced with vacuum cooking method were well within limit of standards.

Pseudo paths towards minimum energy states in network dynamics

NASA Astrophysics Data System (ADS)

Hedayatifar, L.; Hassanibesheli, F.; Shirazi, A. H.; Vasheghani Farahani, S.; Jafari, G. R.

2017-10-01

The dynamics of networks forming on Heider balance theory moves towards lower tension states. The condition derived from this theory enforces agents to reevaluate and modify their interactions to achieve equilibrium. These possible changes in network's topology can be considered as various paths that guide systems to minimum energy states. Based on this theory the final destination of a system could reside on a local minimum energy, ;jammed state;, or the global minimum energy, balanced states. The question we would like to address is whether jammed states just appear by chance? Or there exist some pseudo paths that bound a system towards a jammed state. We introduce an indicator to suspect the location of a jammed state based on the Inverse Participation Ratio method (IPR). We provide a margin before a local minimum where the number of possible paths dramatically drastically decreases. This is a condition that proves adequate for ending up on a jammed states.

Stability of Granular Packings Jammed under Gravity: Avalanches and Unjamming

NASA Astrophysics Data System (ADS)

Merrigan, Carl; Birwa, Sumit; Tewari, Shubha; Chakraborty, Bulbul

Granular avalanches indicate the sudden destabilization of a jammed state due to a perturbation. We propose that the perturbation needed depends on the entire force network of the jammed configuration. Some networks are stable, while others are fragile, leading to the unpredictability of avalanches. To test this claim, we simulated an ensemble of jammed states in a hopper using LAMMPS. These simulations were motivated by experiments with vibrated hoppers where the unjamming times followed power-law distributions. We compare the force networks for these simulated states with respect to their overall stability. The states are classified by how long they remain stable when subject to continuous vibrations. We characterize the force networks through both their real space geometry and representations in the associated force-tile space, extending this tool to jammed states with body forces. Supported by NSF Grant DMR1409093 and DGE1068620.

Performance of Complex Spreading MIMO Systems With Interference

DTIC Science & Technology

2011-06-01

14 III. PERFORMANCE ANALYSIS OF DS -PSK MISO ...............................................15 A. SYSTEM DESCRIPTION...15 Figure 9. BER of DS PSK system for broadband jamming and diversity L=1. ..............20 Figure 10. BER of DS PSK system for...broadband jamming and diversity L=2. .............21 Figure 11. BER of DS PSK system for broadband jamming and diversity L=3. ..............22 Figure 12

A thermodynamic equation of jamming

NASA Astrophysics Data System (ADS)

Lu, Kevin; Pirouz Kavehpour, H.

2008-03-01

Materials ranging from sand to fire-retardant to toothpaste are considered fragile, able to exhibit both solid and fluid-like properties across the jamming transition. Guided by granular flow experiments, our equation of jammed states is path-dependent, definable at different athermal equilibrium states. The non-equilibrium thermodynamics based on a structural temperature incorporate physical ageing to address the non-exponential, non-Arrhenious relaxation of granular flows. In short, jamming is simply viewed as a thermodynamic transition that occurs to preserve a positive configurational entropy above absolute zero. Without any free parameters, the proposed equation-of-state governs the mechanism of shear-banding and the associated features of shear-softening and thickness-invariance.

Information Warfare-Worthy Jamming Attack Detection Mechanism for Wireless Sensor Networks Using a Fuzzy Inference System

PubMed Central

Misra, Sudip; Singh, Ranjit; Rohith Mohan, S. V.

2010-01-01

The proposed mechanism for jamming attack detection for wireless sensor networks is novel in three respects: firstly, it upgrades the jammer to include versatile military jammers; secondly, it graduates from the existing node-centric detection system to the network-centric system making it robust and economical at the nodes, and thirdly, it tackles the problem through fuzzy inference system, as the decision regarding intensity of jamming is seldom crisp. The system with its high robustness, ability to grade nodes with jamming indices, and its true-detection rate as high as 99.8%, is worthy of consideration for information warfare defense purposes. PMID:22319307

Controllable surface haptics via particle jamming and pneumatics.

PubMed

Stanley, Andrew A; Okamura, Allison M

2015-01-01

The combination of particle jamming and pneumatics allows the simultaneous control of shape and mechanical properties in a tactile display. A hollow silicone membrane is molded into an array of thin cells, each filled with coffee grounds such that adjusting the vacuum level in any individual cell rapidly switches it between flexible and rigid states. The array clamps over a pressure-regulated air chamber with internal mechanisms designed to pin the nodes between cells at any given height. Various sequences of cell vacuuming, node pinning, and chamber pressurization allow the surface to balloon into a variety of shapes. Experiments were performed to expand existing physical models of jamming at the inter-particle level to define the rheological characteristics of jammed systems from a macroscopic perspective, relevant to force-displacement interactions that would be experienced by human users. Force-displacement data show that a jammed cell in compression fits a Maxwell model and a cell deflected in the center while supported only at the edges fits a Zener model, each with stiffness and damping parameters that increase at higher levels of applied vacuum. This provides framework to tune and control the mechanical properties of a jamming haptic interface.

JAM3 methylation status as a biomarker for diagnosis of preneoplastic and neoplastic lesions of the cervix

PubMed Central

Yin, Aijun; Zhang, Qing; Kong, Xiangnan; Jia, Lin; Yang, Ziyan; Meng, Lihua; Li, Li; Wang, Xiao; Qiao, Yunbo; Lu, Nan; Yang, Qifeng; Shen, Keng; Kong, Beihua

2015-01-01

DNA methylation is clinically relevant to important tumorigenic mechanisms. This study evaluated the methylation status of candidate genes in cervical neoplasia and determined their diagnostic performance in clinical practice. Cervical cancer and normal cervix tissue was used to select the top 5 discriminating loci among 27 loci in 4 genes (CCNA1, CADM1, DAPK1, JAM3), and one locus of JAM3 (region M4) was identified and confirmed with 267 and 224 cervical scrapings from 2 independent colposcopy referral studies. For patients with atypical squamous cells of unknown significance and those with low-grade squamous intraepithelial lesion, with JAM3-M4 compared to a triage marker of hrHPV testing, the specificity for cervical intraepithelial neoplasia 3 CIN3 and cancer cases (CIN3+) / no neoplasia and CIN1 (CIN1−) was significantly increased, from 21.88 to 81.82 and 15.38 to 85.18, respectively. The corresponding positive predictive value (PPV) was increased from 26.47 to 57.14 and 18.52 to 63.64, respectively. For hrHPV-positive patients, compared to a triage marker of cytology testing, JAM3-M4 showed increased specificity and PPV, from 30.67 to 87.65 and 38.82 to 82.14, respectively. We assessed whether JAM3-M4 could distinguish productive from transforming CIN2; the coincidence rate of JAM3-M4 and P16 was as high as 60.5%. PMID:26517242

Command and Control Vulnerabilities to Communications Jamming

DTIC Science & Technology

2013-01-01

becoming-a-big- problem-in-the-middle-east.ars>. 16 Recent examples of satellite jamming include Indonesia jamming a transponder on a Chinese-owned...15. SUBJECT TERMS 16 . SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as Report (SAR) 18. NUMBER OF PAGES 8 19a. NAME OF...that can provide protection against the full array of potential communications threats is the Advanced Extremely High Frequency (AEHF) system

Structure of marginally jammed polydisperse packings of frictionless spheres

NASA Astrophysics Data System (ADS)

Zhang, Chi; O'Donovan, Cathal B.; Corwin, Eric I.; Cardinaux, Frédéric; Mason, Thomas G.; Möbius, Matthias E.; Scheffold, Frank

2015-03-01

We model the packing structure of a marginally jammed bulk ensemble of polydisperse spheres. To this end we expand on the granocentric model [Clusel et al., Nature (London) 460, 611 (2009), 10.1038/nature08158], explicitly taking into account rattlers. This leads to a relationship between the characteristic parameters of the packing, such as the mean number of neighbors and the fraction of rattlers, and the radial distribution function g (r ) . We find excellent agreement between the model predictions for g (r ) and packing simulations, as well as experiments on jammed emulsion droplets. The observed quantitative agreement opens the path towards a full structural characterization of jammed particle systems for imaging and scattering experiments.

Emergent traffic jams

NASA Astrophysics Data System (ADS)

Nagel, Kai; Paczuski, Maya

1995-04-01

We study a single-lane traffic model that is based on human driving behavior. The outflow from a traffic jam self-organizes to a critical state of maximum throughput. Small perturbations of the outflow far downstream create emergent traffic jams with a power law distribution P(t)~t-3/2 of lifetimes t. On varying the vehicle density in a closed system, this critical state separates lamellar and jammed regimes and exhibits 1/f noise in the power spectrum. Using random walk arguments, in conjunction with a cascade equation, we develop a phenomenological theory that predicts the critical exponents for this transition and explains the self-organizing behavior. These predictions are consistent with all of our numerical results.

DMP: Detouring Using Multiple Paths against Jamming Attack for Ubiquitous Networking System

PubMed Central

Kim, Mihui; Chae, Kijoon

2010-01-01

To successfully realize the ubiquitous network environment including home automation or industrial control systems, it is important to be able to resist a jamming attack. This has recently been considered as an extremely threatening attack because it can collapse the entire network, despite the existence of basic security protocols such as encryption and authentication. In this paper, we present a method of jamming attack tolerant routing using multiple paths based on zones. The proposed scheme divides the network into zones, and manages the candidate forward nodes of neighbor zones. After detecting an attack, detour nodes decide zones for rerouting, and detour packets destined for victim nodes through forward nodes in the decided zones. Simulation results show that our scheme increases the PDR (Packet Delivery Ratio) and decreases the delay significantly in comparison with rerouting by a general routing protocol on sensor networks, AODV (Ad hoc On Demand Distance Vector), and a conventional JAM (Jammed Area Mapping) service with one reroute. PMID:22319316

Use of oil-in-water emulsions to control fungal deterioration of strawberry jams.

PubMed

Ribes, Susana; Fuentes, Ana; Talens, Pau; Barat, José M

2016-11-15

This work aimed to control the fungal deterioration of strawberry jams. The antifungal activity of the clove, cinnamon leaf, lemon and mandarin essential oils and their effectiveness in oil-in-water emulsions were evaluated. According to the results obtained, only clove and cinnamon leaf oils were selected to prepare emulsions. All the tested emulsions were stable, independently the amount of polymer and essential oil used. Essential oil loss was affected by the amount of polymer employed to prepare the emulsions. The oil-in-water emulsions with 5.0mg/g xanthan gum, and with 0.55mg/g clove or 0.65mg/g cinnamon leaf essential oil, were used for the in vivo tests. The jams prepared with the oil-in-water emulsions showed a lower fungal decay compared with jams without emulsion. The present work demonstrated that emulsions can be employed to prevent strawberry jam mould spoilage. Copyright © 2016 Elsevier Ltd. All rights reserved.

DMP: detouring using multiple paths against jamming attack for ubiquitous networking system.

PubMed

Kim, Mihui; Chae, Kijoon

2010-01-01

To successfully realize the ubiquitous network environment including home automation or industrial control systems, it is important to be able to resist a jamming attack. This has recently been considered as an extremely threatening attack because it can collapse the entire network, despite the existence of basic security protocols such as encryption and authentication. In this paper, we present a method of jamming attack tolerant routing using multiple paths based on zones. The proposed scheme divides the network into zones, and manages the candidate forward nodes of neighbor zones. After detecting an attack, detour nodes decide zones for rerouting, and detour packets destined for victim nodes through forward nodes in the decided zones. Simulation results show that our scheme increases the PDR (Packet Delivery Ratio) and decreases the delay significantly in comparison with rerouting by a general routing protocol on sensor networks, AODV (Ad hoc On Demand Distance Vector), and a conventional JAM (Jammed Area Mapping) service with one reroute.

Roadside bear viewing opportunities in Yellowstone National Park: characteristics, trends, and influence of whitebark pine

USGS Publications Warehouse

Haroldson, Mark A.; Gunther, Kerry

2014-01-01

Opportunities for viewing grizzly bears (Ursus arctos) and American black bears (U. americanus) from roadways in Yellowstone National Park (YNP) have increased in recent years. Unlike the panhandling bears common prior to the 1970s, current viewing usually involves bears feeding on natural foods. We define roadside bear viewing opportunities that cause traffic congestion as ‘‘bear-jams.’’ We investigated characteristics of bear-jams and their frequency relative to whitebark pine (Pinus albicaulis) cone production, an important fall food for bears, during 1990–2004. We observed a difference in diel distribution of bear-jams between species (x2=70.609, 4 df, P<0.001) with the occurrence of grizzly bear-jams being more crepuscular. We found evidence for decreasing distances between bears and roadways and increasing durations of bears-jams. The annual proportion of bear-jams for both species occurring after the week of 13–19 August were 3–4 times higher during poor cone crop years than good. We suggest that native foods found in road corridors may be especially important to some individual bears during years exhibiting poor whitebark pine crops. We discuss management implications of threats to whitebark pine and increasing habituation of bears to people.

Pectin methyl esterase treatment on high-methoxy pectin for making fruit jam with reduced sugar content.

PubMed

Wang, Yuh-Tai; Lien, Ling-Lan; Chang, Ya-Chu; Wu, James Swi-Bea

2013-01-01

Pectin methyl esterase (PME) has been postulated to catalyse the transacylation reaction between pectin molecules. The present study aimed to prove the occurrence of this reaction. The feasibility of applying PME-catalysed transacylation between high-methoxy pectin molecules in making fruit jam with reduced sugar content was also investigated. PME treatment increased the turbidity and particle size in pectin solution and the molecular weight of pectin, while it decreased the number of methoxy ester linkages and the intensity of the CH₃ absorption peak in the Fourier transform infrared spectrum without changes in the number of total ester linkages in pectin molecules. These findings support the occurrence of PME-catalysed transacylation between pectin molecules. Higher values of hardness, gumminess and chewiness were found in a jam containing PME-treated citrus pectin (10 g L⁻¹) and sugar (350 g L⁻¹) as compared with either a jam containing untreated citrus pectin (10 g L⁻¹) and sugar (350 g L⁻¹) or strawberry jam containing pectin (10 g L⁻¹) from the fruit and sugar (650 g L⁻¹). The demand for sugar in jam making can be greatly reduced by the use of PME-treated high-methoxy pectin. Copyright © 2012 Society of Chemical Industry.

Discrete-element simulation of sea-ice mechanics: Contact mechanics and granular jamming

NASA Astrophysics Data System (ADS)

Damsgaard, A.; Adcroft, A.; Sergienko, O. V.; Stern, A. A.

2017-12-01

Lagrangian models of sea-ice dynamics offer several advantages to Eulerian continuum methods. Spatial discretization on the ice-floe scale is natural for Lagrangian models, which additionally offer the convenience of being able to handle arbitrary sea-ice concentrations. This is likely to improve model performance in ice-marginal zones with strong advection. Furthermore, phase transitions in granular rheology around the jamming limit, such as observed when sea ice moves through geometric confinements, includes sharp thresholds in effective viscosity which are typically ignored in Eulerian models. Granular jamming is a stochastic process dependent on having the right grains in the right place at the right time, and the jamming likelihood over time can be described by a probabilistic model. Difficult to parameterize in continuum formulations, jamming occurs naturally in dense granular systems simulated in a Lagrangian framework, and is a very relevant process controlling sea-ice transport through narrow straits. We construct a flexible discrete-element framework for simulating Lagrangian sea-ice dynamics at the ice-floe scale, forced by ocean and atmosphere velocity fields. Using this framework, we demonstrate that frictionless contact models based on compressive stiffness alone are unlikely to jam, and describe two different approaches based on friction and tensile strength which both result in increased bulk shear strength of the granular assemblage. The frictionless but cohesive contact model, with certain tensile strength values, can display jamming behavior which on the large scale is very similar to a more complex and realistic model with contact friction and ice-floe rotation.

Modification of Turbulent Pipe Flow Equations to Estimate the Vertical Velocity Profiles Under Woody Debris Jams

NASA Astrophysics Data System (ADS)

Cervania, A.; Knack, I. M. W.

2017-12-01

The presence of woody debris (WD) jams in rivers and streams increases the risk of backwater flooding and reduces the navigability of a channel, but adds fish and macroinvertebrate habitat to the stream. When designing river engineering projects engineers use hydraulic models to predict flow behavior around these obstructions. However, the complexities of flow through and beneath WD jams are still poorly understood. By increasing the ability to predict flow behavior around WD jams, landowners and engineers are empowered to develop sustainable practices regarding the removal or placement of WD in rivers and flood plains to balance the desirable and undesirable effects to society and the environment. The objective of this study is to address some of this knowledge gap by developing a method to estimate the vertical velocity profile of flow under WD jams. When flow passes under WD jams, it becomes affected by roughness elements on all sides, similar to turbulent flows in pipe systems. Therefore, the method was developed using equations that define the velocity profiles of turbulent pipe flows: the law of the wall, the logarithmic law, and the velocity defect law. Flume simulations of WD jams were conducted and the vertical velocity profiles were measured along the centerline. A calculated velocity profile was fit to the measured profile through the calibration of eight parameters. An optimal value or range of values have been determined for several of these parameters using cross-validation techniques. The results indicate there may be some promise to using this method in hydraulic models.

Special K: testing the potassium link between radioactive rubidium (86Rb) turnover and metabolic rate.

PubMed

Tomlinson, Sean; Mathialagan, Priya D; Maloney, Shane K

2014-04-01

The measurement of (86)Rb turnover recently has been suggested as a useful method for measuring field metabolic rate in small animals. We investigated a proposed mechanism of (86)Rb turnover, its analogy to K(+), by comparing the turnover of (86)Rb in a model insect, the rhinoceros beetle Xylotrupes gideon, fed a diet of plum jam or plum jam enriched with K(+) or Rb(+). The turnover of (86)Rb in the beetles on the K(+) and the Rb(+) diets was higher than that for beetles on the jam diet (F2,311=32.4; P=1.58×10(-13)). We also exposed the beetles to different ambient temperatures to induce differences in metabolic rate ( ) while feeding them the jam and K(+) diets. was higher at higher ambient temperature (Ta) for both jam (F1,11=14.56; P=0.003) and K(+) (F1,8=15.39; P=0.004) dietary groups, and the turnover of (86)Rb was higher at higher Ta for both jam (F1,11=10.80; P=0.007) and K(+) (F1,8=12.34; P=0.008) dietary groups. There was a significant relationship between (86)Rb turnover and for both the jam (F1,11=35.00; P=1.0×10(-3)) and the K(+) (F1,8=64.33; P=4.3×10(-5)) diets, but the relationship differed between the diets (F1,19=14.07; P=0.001), with a higher (86)Rb turnover in beetles on the K(+)-enriched than on the jam diet at all Ta. We conclude that (86)Rb turnover is related to K(+) metabolism, and that this is the mechanism of the relationship between (86)Rb turnover and . Studies relating (86)Rb turnover to should maintain dietary [K] as close as possible to that of natural diets for the most accurate calibrations for free-ranging animals.

Laser Spot Center Detection and Comparison Test

NASA Astrophysics Data System (ADS)

Zhu, Jun; Xu, Zhengjie; Fu, Deli; Hu, Cong

2018-04-01

High efficiency and precision of the pot center detection are the foundations of avionics instrument navigation and optics measurement basis for many applications. It has noticeable impact on overall system performance. Among them, laser spot detection is very important in the optical measurement technology. In order to improve the low accuracy of the spot center position, the algorithm is improved on the basis of the circle fitting. The pretreatment is used by circle fitting, and the improved adaptive denoising filter for TV repair technology can effectively improves the accuracy of the spot center position. At the same time, the pretreatment and de-noising can effectively reduce the influence of Gaussian white noise, which enhances the anti-jamming capability.

Military Review, July 1992. Volume 72, Number 7

DTIC Science & Technology

1992-07-01

Electronic tensc. A defender’s raid can force the attacker to Operation Concentration Jamming MILITARY REVIEW * July 1992 37 three days of combat actions...electronic warfare plan is ambitious. more, the strength of the OMG is dissipated Blue CPs and transmitters are jammed on both somewhat by the use of...by an airborne CP. Soviet jamming mitted against the flank of the Blue offensive.] was normally directed at deeper, operational Commitment of the OMG

The Anticancer Activity of Sea Buckthorn [Elaeagnus rhamnoides (L.) A. Nelson].

PubMed

Olas, Beata; Skalski, Bartosz; Ulanowska, Karolina

2018-01-01

Various parts of sea buckthorn [ Elaeagnus rhamnoides (L.) A. Nelson], particularly the berries, known also as seaberries, or Siberian pineapples, are characterized by a unique composition of bioactive compounds: phenolic compounds, vitamins (especially vitamin C), unsaturated fatty acids, and phytosterols such as beta-sitosterol. These berries, together with the juices, jams, and oils made from them, have a range of beneficial antioxidant, anti-inflammatory, and anticancer effects. This short review discusses whether sea buckthorn may represent a "golden mean" for the treatment of cancers: It has anti-proliferation properties and can induce apoptosis and stimulate the immune system, and sea buckthorn oil counteracts many side effects of chemotherapy by restoring kidney and liver function, increasing appetite, and keeping patients in general good health. Although the anticancer activity of sea buckthorn has been confirmed by many in vitro and animal in vivo studies, the treatment and prophylactic doses for humans are unknown. Therefore, greater attention should be paid to the development of well-controlled and high-quality clinical experiments in this area.

Numerical test of the Edwards conjecture shows that all packings are equally probable at jamming

NASA Astrophysics Data System (ADS)

Martiniani, Stefano; Schrenk, K. Julian; Ramola, Kabir; Chakraborty, Bulbul; Frenkel, Daan

2017-09-01

In the late 1980s, Sam Edwards proposed a possible statistical-mechanical framework to describe the properties of disordered granular materials. A key assumption underlying the theory was that all jammed packings are equally likely. In the intervening years it has never been possible to test this bold hypothesis directly. Here we present simulations that provide direct evidence that at the unjamming point, all packings of soft repulsive particles are equally likely, even though generically, jammed packings are not. Typically, jammed granular systems are observed precisely at the unjamming point since grains are not very compressible. Our results therefore support Edwards’ original conjecture. We also present evidence that at unjamming the configurational entropy of the system is maximal.

Hyperuniformity, quasi-long-range correlations, and void-space constraints in maximally random jammed particle packings. I. Polydisperse spheres.

PubMed

Zachary, Chase E; Jiao, Yang; Torquato, Salvatore

2011-05-01

Hyperuniform many-particle distributions possess a local number variance that grows more slowly than the volume of an observation window, implying that the local density is effectively homogeneous beyond a few characteristic length scales. Previous work on maximally random strictly jammed sphere packings in three dimensions has shown that these systems are hyperuniform and possess unusual quasi-long-range pair correlations decaying as r(-4), resulting in anomalous logarithmic growth in the number variance. However, recent work on maximally random jammed sphere packings with a size distribution has suggested that such quasi-long-range correlations and hyperuniformity are not universal among jammed hard-particle systems. In this paper, we show that such systems are indeed hyperuniform with signature quasi-long-range correlations by characterizing the more general local-volume-fraction fluctuations. We argue that the regularity of the void space induced by the constraints of saturation and strict jamming overcomes the local inhomogeneity of the disk centers to induce hyperuniformity in the medium with a linear small-wave-number nonanalytic behavior in the spectral density, resulting in quasi-long-range spatial correlations scaling with r(-(d+1)) in d Euclidean space dimensions. A numerical and analytical analysis of the pore-size distribution for a binary maximally random jammed system in addition to a local characterization of the n-particle loops governing the void space surrounding the inclusions is presented in support of our argument. This paper is the first part of a series of two papers considering the relationships among hyperuniformity, jamming, and regularity of the void space in hard-particle packings.

Critical scaling of a jammed system after a quench of temperature.

PubMed

Otsuki, Michio; Hayakawa, Hisao

2012-09-01

Critical behavior of soft repulsive particles after quench of temperature near the jamming transition is numerically investigated. It is found that the plateau of the mean-square displacement of tracer particles and the pressure satisfy critical scaling laws. The critical density for the jamming transition depends on the protocol to prepare the system, while the values of the critical exponents which are consistent with the prediction of a phenomenology are independent of the protocol.

Pinning Susceptibility at the Jamming Transition

NASA Astrophysics Data System (ADS)

Graves, Amy; Padgett, Elliot; Goodrich, Carl; Liu, Andrea

2013-03-01

Jamming in the presence of fixed or pinned obstacles, representing quenched disorder, is a situation of both practical and theoretical interest. We study the jamming of soft, bidisperse discs in which a subset of discs are pinned while the remaining particles equilibrate around them at a given volume fraction. The obstacles provide a supporting structure for the jammed configuration which not only lowers the jamming threshold, ϕJ, but affects the coordination number and other parameters of interest as the critical point is approached. In the limit of low obstacle density, one can calculate a pinning susceptibility χP, analogous to the magnetic susceptibility, with obstacle density playing the role of the magnetic field. The pinning susceptibility is thus expected to diverge in the thermodynamic limit as χP ~| ϕ -ϕJ | -γP . Finite-size scaling calculations allow us to confirm this and calculate the critical exponent, γP. Acknowledgement is made to the Donors of the Petrolium Research Fund administered by the American Chemical Society, Swarthmore College's Eugene M. Lang Faculty Fellowship, NSF grant DMR-1062638 and DOE grant DE-FG02-05ER46199.

Polyelectrolyte scaling laws for microgel yielding near jamming.

PubMed

Bhattacharjee, Tapomoy; Kabb, Christopher P; O'Bryan, Christopher S; Urueña, Juan M; Sumerlin, Brent S; Sawyer, W Gregory; Angelini, Thomas E

2018-02-28

Micro-scale hydrogel particles, known as microgels, are used in industry to control the rheology of numerous different products, and are also used in experimental research to study the origins of jamming and glassy behavior in soft-sphere model systems. At the macro-scale, the rheological behaviour of densely packed microgels has been thoroughly characterized; at the particle-scale, careful investigations of jamming, yielding, and glassy-dynamics have been performed through experiment, theory, and simulation. However, at low packing fractions near jamming, the connection between microgel yielding phenomena and the physics of their constituent polymer chains has not been made. Here we investigate whether basic polymer physics scaling laws predict macroscopic yielding behaviours in packed microgels. We measure the yield stress and cross-over shear-rate in several different anionic microgel systems prepared at packing fractions just above the jamming transition, and show that our data can be predicted from classic polyelectrolyte physics scaling laws. We find that diffusive relaxations of microgel deformation during particle re-arrangements can predict the shear-rate at which microgels yield, and the elastic stress associated with these particle deformations predict the yield stress.

Pressure-Driven Suspension Flow near Jamming

NASA Astrophysics Data System (ADS)

Oh, Sangwon; Song, Yi-qiao; Garagash, Dmitry I.; Lecampion, Brice; Desroches, Jean

2015-02-01

We report here magnetic resonance imaging measurements performed on suspensions with a bulk solid volume fraction (ϕ0) up to 0.55 flowing in a pipe. We visualize and quantify spatial distributions of ϕ and velocity across the pipe at different axial positions. For dense suspensions (ϕ0>0.5 ), we found a different behavior compared to the known cases of lower ϕ0. Our experimental results demonstrate compaction within the jammed region (characterized by a zero macroscopic shear rate) from the jamming limit ϕm≈0.58 at its outer boundary to the random close packing limit ϕrcp≈0.64 at the center. Additionally, we show that ϕ and velocity profiles can be fairly well captured by a frictional rheology accounting for both further compaction of jammed regions as well as normal stress differences.

Rigidity of a Vibrated Amorphous Bi-Dimensional Packing of Grains

NASA Astrophysics Data System (ADS)

Coulais, C.; Dauchot, O.

The Jamming transition can be seen as a general phenomenon occurring whenever a dense assembly of ``things'' gets stuck and resists to an externally applied shear stress. The mechanical response of a vibrated amorphous bi-dimensional packing of grains close to the Jamming transition is investigated. Stress is applied to the media through a constant torque rheometer while surface fraction is tuned around the jamming transition. The rheometer turns, no matter how low is the applied torque. However, its motion is strongly intermittent and displays scale invariance, the fluctuations being maximal at the Jamming transition, where dynamical correlation length had been found to be divergent. We compare our results to previous ones obtained while dragging an intruder at constant force in the same experimental set-up.

Elastogranular Mechanics: Buckling, Jamming, and Structure Formation.

PubMed

Schunter, David J; Brandenbourger, Martin; Perriseau, Sophia; Holmes, Douglas P

2018-02-16

Confinement of a slender body into a granular array induces stress localization in the geometrically nonlinear structure, and jamming, reordering, and vertical dislodging of the surrounding granular medium. By varying the initial packing density of grains and the length of a confined elastica, we identify the critical length necessary to induce jamming, and demonstrate how folds couple with the granular medium to localize along grain boundaries. Above the jamming threshold, the characteristic length of elastica deformation is shown to diverge in a manner that is coupled with the motion and rearrangement of the grains, suggesting the ordering of the granular array governs the deformation of the slender structure. However, overconfinement of the elastica will vertically dislodge grains, a form of stress relaxation in the granular medium that illustrates the intricate coupling in elastogranular interactions.

Elastogranular Mechanics: Buckling, Jamming, and Structure Formation

NASA Astrophysics Data System (ADS)

Schunter, David J.; Brandenbourger, Martin; Perriseau, Sophia; Holmes, Douglas P.

2018-02-01

Confinement of a slender body into a granular array induces stress localization in the geometrically nonlinear structure, and jamming, reordering, and vertical dislodging of the surrounding granular medium. By varying the initial packing density of grains and the length of a confined elastica, we identify the critical length necessary to induce jamming, and demonstrate how folds couple with the granular medium to localize along grain boundaries. Above the jamming threshold, the characteristic length of elastica deformation is shown to diverge in a manner that is coupled with the motion and rearrangement of the grains, suggesting the ordering of the granular array governs the deformation of the slender structure. However, overconfinement of the elastica will vertically dislodge grains, a form of stress relaxation in the granular medium that illustrates the intricate coupling in elastogranular interactions.

Shocks near Jamming

NASA Astrophysics Data System (ADS)

Gómez, Leopoldo R.; Turner, Ari M.; van Hecke, Martin; Vitelli, Vincenzo

2012-02-01

Nonlinear sound is an extreme phenomenon typically observed in solids after violent explosions. But granular media are different. Right when they jam, these fragile and disordered solids exhibit a vanishing rigidity and sound speed, so that even tiny mechanical perturbations form supersonic shocks. Here, we perform simulations in which two-dimensional jammed granular packings are dynamically compressed and demonstrate that the elementary excitations are strongly nonlinear shocks, rather than ordinary phonons. We capture the full dependence of the shock speed on pressure and impact intensity by a surprisingly simple analytical model.

Impacts of Woody Debris on Fluvial Processes and Channel Morphology in Stable and Unstable Streams

DTIC Science & Technology

1996-05-01

flotation of emergent and riparian trees (Howan, 1987), (Figure 2.1). 0 Fetherston et al. (1995) suggest that debris inputs are either "’chronic or episodic...the channel. Jams are therefore commonly located in bend apices or in unstable reaches downstream of knickpoints. Figure 4.2 demonstrates this...observation, showing debris jam locations just downstream of bend apices on a planform plot of Abiaca Creek. Jams do not, however, appear to have a regular

Discrete element modeling of free-standing wire-reinforced jammed granular columns

NASA Astrophysics Data System (ADS)

Iliev, Pavel S.; Wittel, Falk K.; Herrmann, Hans J.

2018-02-01

The use of fiber reinforcement in granular media is known to increase the cohesion and therefore the strength of the material. However, a new approach, based on layer-wise deployment of predetermined patterns of the fiber reinforcement has led self-confining and free-standing jammed structures to become viable. We have developed a novel model to simulate fiber-reinforced granular materials, which takes into account irregular particles and wire elasticity and apply it to study the stability of unconfined jammed granular columns.

Simulation of 2D Granular Hopper Flow

NASA Astrophysics Data System (ADS)

Li, Zhusong; Shattuck, Mark

2012-02-01

Jamming and intermittent granular flow are big problems in industry, and the vertical hopper is a canonical example of these difficulties. We simulate gravity driven flow and jamming of 2D disks in a vertical hopper and compare with identical companion experiments presented in this session. We measure and compare the flow rate and probability for jamming as a function of particle properties and geometry. We evaluate the ability of standard Hertz-Mindlin contact mode to quantitatively predict the experimental flow.

Water Resources and Related Land Management, Buffalo Metropolitan Area, New York

DTIC Science & Technology

1991-04-01

4,797,800 and $2,566,500, respectively. In January 1986, the Buffalo District completed a letter report addressing ice- jam related flood problems at the...opposition to construction of an ice-retentlon structure at Versailles, New York, to reduce damages due to ice- jam flooding at the mouth of the creek. The...consists of two low earth dams In tandem, e:ach with its ,own outle!t works and energJency spillway, and four training dikes. 17 Snags and debris jams

Turmoil, Transition - Triumph? The Democratic Revolution in the Philippines

DTIC Science & Technology

1986-06-01

The entire lobby, mezzanine, bar, and stairways were jammed . We couldn’t even get close to the room in which she was speaking, and that was with her...went to the top of the Manila Hotel to take pictures of the throng. One immediately noticeable difference was the lobby. It was jammed ! The place was...at the entry to the school. It was a real festival atmosphere, and though it was just eight in the morning the school was jammed . Each classroom in

The Physics of Traffic

NASA Astrophysics Data System (ADS)

Davis, L. Craig

2006-03-01

Congestion in freeway traffic is an example of self-organization in the language of complexity theory. Nonequilibrium, first-order phase transitions from free flow cause complex spatiotemporal patterns. Two distinct phases of congestion are observed in empirical traffic data--wide moving jams and synchronous flow. Wide moving jams are characterized by stopped or slowly moving vehicles within the jammed region, which widens and moves upstream at 15-20 km/h. Above a critical density of vehicles, a sudden decrease in the velocity of a lead vehicle can initiate a transition from metastable states to this phase. Human behaviors, especially delayed reactions, are implicated in the formation of jams. The synchronous flow phase results from a bottleneck such as an on-ramp. Thus, in contrast to a jam, the downstream front is pinned at a fixed location. The name of the phase comes from the equilibration (or synchronization) of speed and flow rate across all lanes caused by frequent vehicle lane changes. Synchronous flow occurs when the mainline flow and the rate of merging from an on-ramp are sufficiently large. Large-scale simulations using car-following models reproduce the physical phenomena occurring in traffic and suggest methods to improve flow and mediate congestion.

Rapid jamming avoidance in biosonar.

PubMed

Gillam, Erin H; Ulanovsky, Nachum; McCracken, Gary F

2007-03-07

The sonar systems of bats and dolphins are in many ways superior to man-made sonar and radar systems, and considerable effort has been devoted to understanding the signal-processing strategies underlying these capabilities. A major feature determining the efficiency of sonar systems is the sensitivity to noise and jamming signals. Previous studies indicated that echolocating bats may adjust their signal structure to avoid jamming ('jamming avoidance response'; JAR). However, these studies relied on behavioural correlations and not controlled experiments. Here, we provide the first experimental evidence for JAR in bats. We presented bats (Tadarida brasiliensis) with 'playback stimuli' consisting of recorded echolocation calls at one of six frequencies. The bats exhibited a JAR by shifting their call frequency away from the presented playback frequency. When the approaching bats were challenged by an abrupt change in the playback stimulus, they responded by shifting their call frequencies upwards, away from the playback. Interestingly, even bats initially calling below the playback's frequency shifted their frequencies upwards, 'jumping' over the playback frequency. These spectral shifts in the bats' calls occurred often within less than 200 ms, in the first echolocation call emitted after the stimulus switch-suggesting that rapid jamming avoidance is important for the bat.

Self-organized magnetic particles to tune the mechanical behavior of a granular system

NASA Astrophysics Data System (ADS)

Cox, Meredith; Wang, Dong; Barés, Jonathan; Behringer, Robert P.

2016-09-01

Above a certain density a granular material jams. This property can be controlled by either tuning a global property, such as the packing fraction or by applying shear strain, or at the micro-scale by tuning grain shape, inter-particle friction or externally controlled organization. Here, we introduce a novel way to change a local granular property by adding a weak anisotropic magnetic interaction between particles. We measure the evolution of the pressure, P, and coordination number, Z, for a packing of 2D photo-elastic disks, subject to uniaxial compression. A fraction R m of the particles have embedded cuboidal magnets. The strength of the magnetic interactions between particles is too weak to have a strong direct effect on P or Z when the system is jammed. However, the magnetic interactions play an important role in the evolution of latent force networks when systems containing a large enough fraction of the particles with magnets are driven through unjammed to jammed states. In this case, a statistically stable network of magnetic chains self-organizes before jamming and overlaps with force chains once jamming occurs, strengthening the granular medium. This property opens a novel way to control mechanical properties of granular materials.

Nuclear Attack on U.S. Space-Based Assets: Current Strategy, Policy, Reality, and Implications for the Future.

DTIC Science & Technology

1998-06-05

other.46 This can be useful when certain links 70 have been negated through the destruction of a ground station or actual jamming or interference...system is to attack the enemy’s ground station.59 The link segment can be jammed or spoofed60. However, the DoD has nothing in its inventory currently...currently conducted primarily by jamming assets that prevent the enemy use of his systems. These systems are classified and can only be discussed in

Apparatus and method for controlling the rotary airlocks in a coal processing system by reversing the motor current rotating the air lock

DOEpatents

Groombridge, Clifton E.

1996-01-01

An improvement to a coal processing system where hard materials found in the coal may cause jamming of either inflow or outflow rotary airlocks, each driven by a reversible motor. The instantaneous current used by the motor is continually monitored and compared to a predetermined value. If an overcurrent condition occurs, indicating a jamming of the airlock, a controller means starts a "soft" reverse rotation of the motor thereby clearing the jamming. Three patterns of the motor reversal are provided.

Distribution and characterization of in-channel large wood in relation to geomorphic patterns on a low-gradient river

USGS Publications Warehouse

Moulin, Bertrand; Schenk, Edward R.; Hupp, Cliff R.

2011-01-01

A 177 river km georeferenced aerial survey of in-channel large wood (LW) on the lower Roanoke River, NC was conducted to determine LW dynamics and distributions on an eastern USA low-gradient large river. Results indicate a system with approximately 75% of the LW available for transport either as detached individual LW or as LW in log jams. There were approximately 55 individual LW per river km and another 59 pieces in log jams per river km. Individual LW is a product of bank erosion (73% is produced through erosion) and is isolated on the mid and upper banks at low flow. This LW does not appear to be important for either aquatic habitat or as a human risk. Log jams rest near or at water level making them a factor in bank complexity in an otherwise homogenous fine-grained channel. A segmentation test was performed using LW frequency by river km to detect breaks in longitudinal distribution and to define homogeneous reaches of LWfrequency. Homogeneous reaches were then analyzed to determine their relationship to bank height, channel width/depth, sinuosity, and gradient. Results show that log jams are a product of LW transport and occur more frequently in areas with high snag concentrations, low to intermediate bank heights, high sinuosity, high local LW recruitment rates, and narrow channel widths. The largest concentration of log jams (21.5 log jams/km) occurs in an actively eroding reach. Log jam concentrations downstream of this reach are lower due to a loss of river competency as the channel reaches sea level and the concurrent development of unvegetated mudflats separating the active channel from the floodplain forest. Substantial LW transport occurs on this low-gradient, dam-regulated large river; this study, paired with future research on transport mechanisms should provide resource managers and policymakers with options to better manage aquatic habitat while mitigating possible negative impacts to human interests.

CASK interacts with PMCA4b and JAM-A on the Mouse Sperm Flagellum to Regulate Ca2+ Homeostasis and Motility1

PubMed Central

Aravindan, Rolands G.; Fomin, Victor P.; Naik, Ulhas P.; Modelski, Mark J.; Naik, Meghna U.; Galileo, Deni S.; Duncan, Randall L.; Martin-DeLeon, Patricia A.

2012-01-01

Deletion of the highly conserved gene for the major Ca2+ efflux pump, Plasma membrane calcium/calmodulin-dependent ATPase 4b (Pmca4b), in the mouse leads to loss of progressive and hyperactivated sperm motility and infertility. Here we first demonstrate that compared to wild-type (WT), Junctional adhesion molecule-A (Jam-A) null sperm, previously shown to have motility defects and an abnormal mitochondrial phenotype reminiscent of that seen in Pmca4b nulls, exhibit reduced (P<0.001) ATP levels, significantly (P<0.001) greater cytosolic Ca2+ concentration ([Ca2+]c) and ~10-fold higher mitochondrial sequestration, indicating Ca2+ overload. Investigating the mechanism involved, we used coimmunoprecipitation studies to show that CASK (Ca2+/calmodulin-dependent serine kinase), identified for the first time on the sperm flagellum where it co-localizes with both PMCA4b and JAM-A on the proximal principal piece, acts as a common interacting partner of both. Importantly, CASK binds alternatively and non-synergistically with each of these molecules via its single PDZ (PDS-95/Dlg/ZO-1) domain to either inhibit or promote efflux. In the absence of CASK-JAM-A interaction in Jam-A null sperm, CASK-PMCA4b interaction is increased, resulting in inhibition of PMCA4b’s enzymatic activity, consequent Ca2+ accumulation, and a ~6-fold over-expression of constitutively ATP-utilizing CASK, compared to WT. Thus, CASK negatively regulates PMCA4b by directly binding to it and JAM-A positively regulates it indirectly through CASK. The decreased motility is likely due to the collateral net deficit in ATP observed in nulls. Our data indicate that Ca2+ homeostasis in sperm is maintained by the relative ratios of CASK-PMCA4b and CASK-JAM-A interactions. PMID:22020416

Influence of dry cohesion on the micro- and macro-mechanical properties of dense polydisperse powders & grains

NASA Astrophysics Data System (ADS)

Kievitsbosch, Robert; Smit, Hendrik; Magnanimo, Vanessa; Luding, Stefan; Taghizadeh, Kianoosh

2017-06-01

Understanding how cohesive granular materials behave is of interest for many industrial applications, such as pharmaceutical or food and civil engineering. Models of the behaviour of granular materials on the microscopic scale can be used to obtain macroscopic continuum relations by a micro-macro transition approach. The Discrete Element Method (DEM) is used to inspect the influence of cohesion on the micro and macro behaviour of granular assemblies by using an elasto-plastic cohesive contact model. Interestingly, we observe that frictional samples prepared with different cohesion values show a significant difference in pressure and coordination number in the jammed regime; the differences become more pronounced when packings are closer to the jamming density, i.e. the lowest density where the system is mechanically stable. Furthermore, we observe that cohesion has an influence on the jamming density for frictional samples, but there is no influence on the jamming density for frictionless samples.

Universal rescaling of flow curves for yield-stress fluids close to jamming

NASA Astrophysics Data System (ADS)

Dinkgreve, M.; Paredes, J.; Michels, M. A. J.; Bonn, D.

2015-07-01

The experimental flow curves of four different yield-stress fluids with different interparticle interactions are studied near the jamming concentration. By appropriate scaling with the distance to jamming all rheology data can be collapsed onto master curves below and above jamming that meet in the shear-thinning regime and satisfy the Herschel-Bulkley and Cross equations, respectively. In spite of differing interactions in the different systems, master curves characterized by universal scaling exponents are found for the four systems. A two-state microscopic theory of heterogeneous dynamics is presented to rationalize the observed transition from Herschel-Bulkley to Cross behavior and to connect the rheological exponents to microscopic exponents for the divergence of the length and time scales of the heterogeneous dynamics. The experimental data and the microscopic theory are compared with much of the available literature data for yield-stress systems.

Full Envelope Reconfigurable Control Design for the X-33 Vehicle

NASA Technical Reports Server (NTRS)

Cotting, M. Christopher; Burken, John J.; Lee, Seung-Hee (Technical Monitor)

2001-01-01

In the event of a control surface failure, the purpose of a reconfigurable control system is to redistribute the control effort among the remaining working surfaces such that satisfactory stability and performance are retained. An Off-line Nonlinear General Constrained Optimization (ONCO) approach was used for the reconfigurable X-33 control design method. Three example failures are shown using a high fidelity 6 DOF simulation (case I ascent with a left body flap jammed at 25 deg.; case 2 entry with a right inboard elevon jam at 25 deg.; and case 3, landing (TAEM) with a left rudder jam at -30 deg.) Failure comparisons between responses with the nominal controller and reconfigurable controllers show the benefits of reconfiguration. Single jam aerosurface failures were considered, and failure detection and identification is considered accomplished in the actuator controller. The X-33 flight control system will incorporate reconfigurable flight control in the baseline system.

High-resolution of particle contacts via fluorophore exclusion in deep-imaging of jammed colloidal packings

NASA Astrophysics Data System (ADS)

Kyeyune-Nyombi, Eru; Morone, Flaviano; Liu, Wenwei; Li, Shuiqing; Gilchrist, M. Lane; Makse, Hernán A.

2018-01-01

Understanding the structural properties of random packings of jammed colloids requires an unprecedented high-resolution determination of the contact network providing mechanical stability to the packing. Here, we address the determination of the contact network by a novel strategy based on fluorophore signal exclusion of quantum dot nanoparticles from the contact points. We use fluorescence labeling schemes on particles inspired by biology and biointerface science in conjunction with fluorophore exclusion at the contact region. The method provides high-resolution contact network data that allows us to measure structural properties of the colloidal packing near marginal stability. We determine scaling laws of force distributions, soft modes, correlation functions, coordination number and free volume that define the universality class of jammed colloidal packings and can be compared with theoretical predictions. The contact detection method opens up further experimental testing at the interface of jamming and glass physics.

Jamming for a system of granular crosses

NASA Astrophysics Data System (ADS)

Shang, Zegan; Zheng, Hu; Wang, Dong; Bares, Jonathan; Behringer, Robert

A disordered stress-free granular packing can be turned into a rigid structure, which is called jammed state, by increasing the density of particles per unit volume or by applying shear deformation. The jamming behavior of systems made of of 2D circular discs have been investigated in detail, but very little is known about the special geometry particles, particularly non-convex particles like crosses. Here, we perform an experimental study on the jamming of a system of quasi-2D granular crosses. In the present experiments, we measure the pressure, and coordinate number evolution of a 2D packing of photo-elastic cross discs. This talk will present results from a simple shear experiment for stresses and for the order parameter associated with the cross orientation and its correlation. We acknowledge support from NSF Grant No. DMR1206351, NASA Grant No. NNX15AD38G and the W.M. Keck Foundation.

Tuning Shear Jamming by Basal Assisted Couette Shear

NASA Astrophysics Data System (ADS)

Zhao, Yiqiu; Barés, Jonathan; Behringer, Robert

Granular matter with packing fraction ϕS < ϕ <ϕJ can be jammed by applying shear strain. However, the stress-strain relation in shear jamming transition is not very well understood. Part of the difficulty is that the strain inside the granular system is very complicated and hard to control. In this work, by using a novel Couette shear apparatus capable of generating arbitrary shear profiles, we study the stress-strain relation during shear jamming transition for granular system under different kinds of controlled interior strain. The novel Couette shear apparatus consists of 21 independently movable rings and two circular boundaries. The apparatus can shear the granular sample not only from the boundaries but also from the bottom. The granular sample is made of about 2000 bi-disperse photo elastic disks, making it possible to extract force information. This work is supported by NSF-DMR1206351, DMS1248071, NASA NNX15AD38G.

Active acoustic interference elicits echolocation changes in heterospecific bats.

PubMed

Jones, Te K; Wohlgemuth, Melville J; Conner, William E

2018-06-27

Echolocating bats often forage in the presence of both conspecific and heterospecific individuals who have the potential to produce acoustic interference. Recent studies have shown that at least one bat species, the Brazilian free-tailed bat ( Tadarida brasiliensis ), produces specialized social signals that disrupt the sonar of conspecific competitors. We herein discuss the differences between passive and active jamming signals and test whether heterospecific jamming occurs in species overlapping spatiotemporally as well as whether such interference elicits a jamming avoidance response (JAR). We compare the capture rates of tethered moths and the echolocation parameters of big brown bats ( Eptesicus fuscus ) challenged with the playback of the jamming signal normally produced by Brazilian free-tailed bats and playback of deconstructed versions of this signal. There were no differences in the capture rates of targets with and without the jamming signal although significant changes in both spectral and temporal features of the bats' echolocation were observed. These changes are consistent with improvements of the signal-to-noise ratio in the presence of acoustic interference. Accordingly, we propose to expand the traditional definition of the JAR, stating that echolocation changes in response to interference should decrease similarity between the two signals, to include any change that increases the ability to separate returning echoes from active jamming stimuli originating from conspecific and heterospecific organisms. Flexibility in echolocation is an important characteristic for overcoming various forms of acoustic interference and may serve a purpose in interspecific interactions as well as intraspecific ones. © 2018. Published by The Company of Biologists Ltd.

A model of jam formation in congested traffic

NASA Astrophysics Data System (ADS)

Bunzarova, N. Zh; Pesheva, N. C.; Priezzhev, V. B.; Brankov, J. G.

2017-12-01

We study a model of irreversible jam formation in congested vehicular traffic on an open segment of a single-lane road. The vehicles obey a stochastic discrete-time dynamics which is a limiting case of the generalized Totally Asymmetric Simple Exclusion Process. Its characteristic features are: (a) the existing clusters of jammed cars cannot break into parts; (b) when the leading vehicle of a cluster hops to the right, the whole cluster follows it deterministically, and (c) any two clusters of vehicles, occupying consecutive positions on the chain, may become nearest-neighbors and merge irreversibly into a single cluster. The above dynamics was used in a one-dimensional model of irreversible aggregation by Bunzarova and Pesheva [Phys. Rev. E 95, 052105 (2017)]. The model has three stationary non-equilibrium phases, depending on the probabilities of injection (α), ejection (β), and hopping (p) of particles: a many-particle one, MP, a completely jammed phase CF, and a mixed MP+CF phase. An exact expression for the stationary probability P(1) of a completely jammed configuration in the mixed MP+CF phase is obtained. The gap distribution between neighboring clusters of jammed cars at large lengths L of the road is studied. Three regimes of evolution of the width of a single gap are found: (i) growing gaps with length of the order O(L) when β > p; (ii) shrinking gaps with length of the order O(1) when β < p; and (iii) critical gaps at β = p, of the order O(L 1/2). These results are supported by extensive Monte Carlo calculations.

Jamming dynamics of stretch-induced surfactant release by alveolar type II cells

PubMed Central

Majumdar, Arnab; Arold, Stephen P.; Bartolák-Suki, Erzsébet; Parameswaran, Harikrishnan

2012-01-01

Secretion of pulmonary surfactant by alveolar epithelial type II cells is vital for the reduction of interfacial surface tension, thus preventing lung collapse. To study secretion dynamics, rat alveolar epithelial type II cells were cultured on elastic membranes and cyclically stretched. The amounts of phosphatidylcholine, the primary lipid component of surfactant, inside and outside the cells, were measured using radiolabeled choline. During and immediately after stretch, cells secreted less surfactant than unstretched cells; however, stretched cells secreted significantly more surfactant than unstretched cells after an extended lag period. We developed a model based on the hypothesis that stretching leads to jamming of surfactant traffic escaping the cell, similar to vehicular traffic jams. In the model, stretch increases surfactant transport from the interior to the exterior of the cell. This transport is mediated by a surface layer with a finite capacity due to the limited number of fusion pores through which secretion occurs. When the amount of surfactant in the surface layer approaches this capacity, interference among lamellar bodies carrying surfactant reduces the rate of secretion, effectively creating a jam. When the stretch stops, the jam takes an extended time to clear, and subsequently the amount of secreted surfactant increases. We solved the model analytically and show that its dynamics are consistent with experimental observations, implying that surfactant secretion is a fundamentally nonlinear process with memory representing collective behavior at the level of single cells. Our results thus highlight the importance of a jamming dynamics in stretch-induced cellular secretory processes. PMID:22033531

Ice Jam Flooding and Mitigation: Lower Platte River Basin, Nebraska,

DTIC Science & Technology

1996-01-01

providing much valuable information about ice jam locations and dates. The contents of this report are not to be used for advertising or promotional...52 v Ice Jam Flooding and Mitigation Lower Platte River Basin, Nebraska KATHLEEN D. WHITE AND ROGER L. KAY INTRODUCTION with a...depth below 49 50 I ’ I I I Depth of Charge Below Bottom of Ice Sheet 40- N 0 ft 11 0.6 - 0 1.6 7: V 2.5 .0 -30t- A 3.3 •:Az 6.6 2l) - 3.0 0 20- 0 L

Unifying Suspension and Granular flows near Jamming

NASA Astrophysics Data System (ADS)

DeGiuli, Eric; Wyart, Matthieu

2017-06-01

Rheological properties of dense flows of hard particles are singular as one approaches the jamming threshold where flow ceases, both for granular flows dominated by inertia, and for over-damped suspensions. Concomitantly, the lengthscale characterizing velocity correlations appears to diverge at jamming. Here we review a theoretical framework that gives a scaling description of stationary flows of frictionless particles. Our analysis applies both to suspensions and inertial flows of hard particles. We report numerical results in support of the theory, and show the phase diagram that results when friction is added, delineating the regime of validity of the frictionless theory.

A study of optimal abstract jamming strategies vs. noncoherent MFSK

NASA Technical Reports Server (NTRS)

Mceliece, R. J.; Rodemich, E. R.

1983-01-01

The present investigation is concerned with the performance of uncoded MFSK modulation in the presence of arbitrary additive jamming, taking into account the objective to devise robust antijamming strategies. An abstract model is considered, giving attention to the signal strength as a nonnegative real number X, the employment of X as a random variable, its distribution function G(x), the transmitter's strategy G, the jamming noise as an M-dimensional random vector Z, and the error probability. A summary of previous work on the considered problem is provided, and the results of the current study are presented.

Cell Motility and Jamming across the EMT

NASA Astrophysics Data System (ADS)

Grosser, Steffen; Oswald, Linda; Lippoldt, Jürgen; Heine, Paul; Kaes, Josef A.

We use single-cell tracking and cell shape analysis to highlight the different roles that cell jamming plays in the behaviour of epithelial vs. mesenchymal mammary breast cell lines (MCF-10A, MDA-MB-231) in 2D adherent culture. An automatic segmentation allows for the evaluation of cell shapes, which we compare to predictions made by the self-propelled vertex (SPV) model. On top of that, we employ co-cultures to study the emerging demixing behaviour of these cell lines, demonstrating that the mesenchymal MDA-MB-231 cell line forms unjammed islands within the jammed collective.

Hopper Flow: Experiments and Simulation

NASA Astrophysics Data System (ADS)

Li, Zhusong; Shattuck, Mark

2013-03-01

Jamming and intermittent granular flow are important problems in industry, and the vertical hopper is a canonical example. Clogging of granular hoppers account for significant losses across many industries. We use realistic DEM simulations of gravity driven flow in a hopper to examine flow and jamming of 2D disks and compare with identical companion experiments. We use experimental data to validate simulation parameters and the form of the inter particle force law. We measure and compare flow rate, emptying times, jamming statistics, and flow fields as a function of opening angle and opening size in both experiment and simulations. Suppored by: NSF-CBET-0968013

Training for Decisive Action: Stories of Mission Command. Collected Insights from Commanders and Leaders on their Experience at the National Training Center

DTIC Science & Technology

2014-01-01

If there is no control then friction builds into a colossal traffic jam . It takes a traffic cop that understands the susceptible points of friction...to force control back into the jam so that movement can regain momentum. My position at the BCT TAC, south of the Whale Gap, acted as an effective...him that the COEFOR would most likely rouse the IDP camp north of the Whale Gap to create a massive traffic jam . The plan took all of this into

Influence of different processing and storage conditions on in vitro bioaccessibility of polyphenols in black carrot jams and marmalades.

PubMed

Kamiloglu, Senem; Pasli, Ayca Ayfer; Ozcelik, Beraat; Van Camp, John; Capanoglu, Esra

2015-11-01

Black carrot is indicated to play an important role in nutrition, as it comprises a variety of health-promoting components, including polyphenols. The objective of the present study was to monitor the stability of total phenolics, antioxidant capacity and phenolic acids in black carrot jams and marmalades after processing, storage and in vitro gastrointestinal digestion. Total phenolic content and antioxidant capacity were determined using spectrophotometric methods, whereas phenolic acids were identified using HPLC-PDA. Jam and marmalade processing significantly decreased total phenolics (89.2-90.5%), antioxidant capacity (83.3-91.3%) and phenolic acids (49.5-96.7%) (p < 0.05). After 20 weeks of storage, the percent decrease in total phenolics in samples stored at 25 °C (26.4-48.0%) was slightly higher than the samples stored at 4 °C (21.0-42.5%). In addition, jam and marmalade processing led to increases in the percent recovery of bioaccessible total phenolics (7.2-12.6%) and phenolic acids (4.7-31.5%), as well as antioxidant capacity (1.4-8.1%). In conclusion, current study highlighted black carrot jams and marmalades as good sources of polyphenols, with high bioaccessibility levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effect of processing and storage on the antioxidant ellagic acid derivatives and flavonoids of red raspberry (Rubus idaeus) jams.

PubMed

Zafrilla, P; Ferreres, F; Tomás-Barberán, F A

2001-08-01

From red raspberries, ellagic acid, its 4-arabinoside, its 4' (4' '-acetyl) arabinoside, and its 4' (4' '-acetyl)xyloside, as well as quercetin and kaempferol 3-glucosides, were identified. In addition, two unidentified ellagic acid derivatives were detected. The free radical scavenging activity of the ellagic acid derivatives was evaluated by using the DPPH method and compared to that of Trolox. All of the isolated compounds showed antioxidant activity. The effect of processing to obtain jams on raspberry phenolics was evaluated. The flavonol content decreased slightly with processing and more markedly during storage of the jams. The ellagic acid derivatives, with the exception of ellagic acid itself, remained quite stable with processing and during 6 months of jam storage. The content of free ellagic acid increased 3-fold during the storage period. The initial content (10 mg/kg of fresh weight of raspberries) increased 2-fold with processing, and it continued increasing up to 35 mg/kg after 1 month of storage of the jam. Then a slight decrease was observed until 6 months of storage had elapsed. The increase observed in ellagic acid could be explained by a release of ellagic acid from ellagitannins with the thermal treatment.

Processing black mulberry into jam: effects on antioxidant potential and in vitro bioaccessibility.

PubMed

Tomas, Merve; Toydemir, Gamze; Boyacioglu, Dilek; Hall, Robert D; Beekwilder, Jules; Capanoglu, Esra

2017-08-01

Black mulberries (Morus nigra) were processed into jam on an industrialised scale, including the major steps of: selection of frozen black mulberries, adding glucose-fructose syrup and water, cooking, adding citric acid and apple pectin, removing seeds, and pasteurisation. Qualitative and quantitative determinations of antioxidants in black mulberry samples were performed using spectrophotometric methods, as well as HPLC- and LC-QTOF-MS-based measurements. These analyses included the determination of total polyphenolic content, % polymeric colour, total and individual anthocyanin contents, antioxidant capacity, and in vitro bioaccessibility in processing samples. Jam processing led to a significant reduction in total phenolics (88%), total flavonoids (89%), anthocyanins (97%), and antioxidant capacity (88-93%) (P < 0.05). Individual anthocyanin contents, determined using HPLC analysis, also showed a significant decrease (∼99% loss). In contrast, % recovery of bioaccessible total phenolics, anthocyanins, and antioxidant capacity (ABTS assay) increased after jam processing (16%, 12%, and 37%, respectively). Fruit processing resulted in losses of polyphenols, anthocyanins, and antioxidant capacity of black mulberry jam. Optimisation of food processing could help to protect the phenolic compounds in fruits which might be helpful for the food industry to minimise the antioxidant loss and improve the final product quality. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

JAMS - a software platform for modular hydrological modelling

NASA Astrophysics Data System (ADS)

Kralisch, Sven; Fischer, Christian

2015-04-01

Current challenges of understanding and assessing the impacts of climate and land use changes on environmental systems demand for an ever-increasing integration of data and process knowledge in corresponding simulation models. Software frameworks that allow for a seamless creation of integrated models based on less complex components (domain models, process simulation routines) have therefore gained increasing attention during the last decade. JAMS is an Open-Source software framework that has been especially designed to cope with the challenges of eco-hydrological modelling. This is reflected by (i) its flexible approach for representing time and space, (ii) a strong separation of process simulation components from the declarative description of more complex models using domain specific XML, (iii) powerful analysis and visualization functions for spatial and temporal input and output data, and (iv) parameter optimization and uncertainty analysis functions commonly used in environmental modelling. Based on JAMS, different hydrological and nutrient-transport simulation models were implemented and successfully applied during the last years. We will present the JAMS core concepts and give an overview of models, simulation components and support tools available for that framework. Sample applications will be used to underline the advantages of component-based model designs and to show how JAMS can be used to address the challenges of integrated hydrological modelling.

Geometric constraints during epithelial jamming

NASA Astrophysics Data System (ADS)

Atia, Lior; Bi, Dapeng; Sharma, Yasha; Mitchel, Jennifer A.; Gweon, Bomi; Koehler, Stephan A.; DeCamp, Stephen J.; Lan, Bo; Kim, Jae Hun; Hirsch, Rebecca; Pegoraro, Adrian F.; Lee, Kyu Ha; Starr, Jacqueline R.; Weitz, David A.; Martin, Adam C.; Park, Jin-Ah; Butler, James P.; Fredberg, Jeffrey J.

2018-06-01

As an injury heals, an embryo develops or a carcinoma spreads, epithelial cells systematically change their shape. In each of these processes cell shape is studied extensively whereas variability of shape from cell to cell is regarded most often as biological noise. But where do cell shape and its variability come from? Here we report that cell shape and shape variability are mutually constrained through a relationship that is purely geometrical. That relationship is shown to govern processes as diverse as maturation of the pseudostratified bronchial epithelial layer cultured from non-asthmatic or asthmatic donors, and formation of the ventral furrow in the Drosophila embryo. Across these and other epithelial systems, shape variability collapses to a family of distributions that is common to all. That distribution, in turn, is accounted for by a mechanistic theory of cell-cell interaction, showing that cell shape becomes progressively less elongated and less variable as the layer becomes progressively more jammed. These findings suggest a connection between jamming and geometry that spans living organisms and inert jammed systems, and thus transcends system details. Although molecular events are needed for any complete theory of cell shape and cell packing, observations point to the hypothesis that jamming behaviour at larger scales of organization sets overriding geometric constraints.

Simulation of a Magneto-Rheological Fluid Based, Jamming, Soft Gripper Using the Soft Sphere DEM in LIGGGHTS

NASA Astrophysics Data System (ADS)

Leps, Thomas; Hartzell, Christine; Wereley, Norman; Choi, Young

2017-11-01

Jamming soft grippers are excellent universal grippers due to their low dependence on the shape of objects to be grabbed, and low stiffness, mitigating the need for object shape data and expensive force control of a stiff system. These grippers now rely on jamming transitions of dry grains under atmospheric pressure to hold objects. In order to expand their use to space environments, a gripper using magnetic actuation of a magneto-rheological fluid (MR Gripper) is being developed. The MR fluid is a suspension of μm scale iron grains in a silicone oil. When un-magnetized the fluid behaves as a dense suspension with low Bagnold number. When magnetized, it behaves like a jammed granular material, with magnetic forces between the grains dominating. We are simulating the gripper using LIGGGHTS, an open-source soft sphere DEM code. We have modeled both the deformable gripper membrane and the MR fluid itself using the LIGGGHTS framework. To our knowledge, this is the first time that the induced magnetic dipoles required to accurately simulate the jamming behavior of MR fluids have been modeled in LIGGGHTS. This simulation allows the rapid optimization of the hardware and magnetic field geometries, as well as the fluid behavior, without time consuming, and costly prototype revisions.

Citrus medica: nutritional, phytochemical composition and health benefits - a review.

PubMed

Chhikara, Navnidhi; Kour, Ragni; Jaglan, Sundeep; Gupta, Pawan; Gat, Yogesh; Panghal, Anil

2018-04-25

Citrus medica (Citron) is an underutilized fruit plant having various bioactive components in all parts of the plant. The major bioactive compounds present are iso-limonene, citral, limonene, phenolics, flavonones, vitamin C, pectin, linalool, decanal, and nonanal, accounting for several health benefits. Pectin and heteropolysachharides also play a major role as dietary fibers. The potential impact of citron and its bioactive components to prevent or reverse destructive deregulated processes responsible for certain diseases has attracted different researchers' attention. The fruit has numerous nutraceutical benefits, proven by pharmacological studies; for example, anti-catarrhal, capillary protector, anti-hypertensive, diuretic, antibacterial, antifungal, anthelmintic, antimicrobial, analgesic, strong antioxidant, anticancerous, antidiabetic, estrogenic, antiulcer, cardioprotective, and antihyperglycemic. The present review explores new insights into the benefits of citron in various body parts. Throughout the world, citron has been used in making carbonated drinks, alcoholic beverages, syrup, candied peels, jams, marmalade, cordials, and many other value added products, which suggests it is an appropriate raw material to develop healthy processed food. In the present review, the fruit taxonomical classification, beneficial phytochemicals, antioxidant activities, and health benefits are discussed.

The Anticancer Activity of Sea Buckthorn [Elaeagnus rhamnoides (L.) A. Nelson

PubMed Central

Olas, Beata; Skalski, Bartosz; Ulanowska, Karolina

2018-01-01

Various parts of sea buckthorn [Elaeagnus rhamnoides (L.) A. Nelson], particularly the berries, known also as seaberries, or Siberian pineapples, are characterized by a unique composition of bioactive compounds: phenolic compounds, vitamins (especially vitamin C), unsaturated fatty acids, and phytosterols such as beta-sitosterol. These berries, together with the juices, jams, and oils made from them, have a range of beneficial antioxidant, anti-inflammatory, and anticancer effects. This short review discusses whether sea buckthorn may represent a “golden mean” for the treatment of cancers: It has anti-proliferation properties and can induce apoptosis and stimulate the immune system, and sea buckthorn oil counteracts many side effects of chemotherapy by restoring kidney and liver function, increasing appetite, and keeping patients in general good health. Although the anticancer activity of sea buckthorn has been confirmed by many in vitro and animal in vivo studies, the treatment and prophylactic doses for humans are unknown. Therefore, greater attention should be paid to the development of well-controlled and high-quality clinical experiments in this area. PMID:29593547

[Research on fuzzy proportional-integral-derivative control of master-slave minimally invasive operation robot driver].

PubMed

Zhao, Ximei; Ren, Chengyi; Liu, Hao; Li, Haogyi

2014-12-01

Robotic catheter minimally invasive operation requires that the driver control system has the advantages of quick response, strong anti-jamming and real-time tracking of target trajectory. Since the catheter parameters of itself and movement environment and other factors continuously change, when the driver is controlled using traditional proportional-integral-derivative (PID), the controller gain becomes fixed once the PID parameters are set. It can not change with the change of the parameters of the object and environmental disturbance so that its change affects the position tracking accuracy, and may bring a large overshoot endangering patients' vessel. Therefore, this paper adopts fuzzy PID control method to adjust PID gain parameters in the tracking process in order to improve the system anti-interference ability, dynamic performance and tracking accuracy. The simulation results showed that the fuzzy PID control method had a fast tracking performance and a strong robustness. Compared with those of traditional PID control, the feasibility and practicability of fuzzy PID control are verified in a robotic catheter minimally invasive operation.

Phytochemical composition and in vitro functional properties of three wild rose hips and their traditional preserves.

PubMed

Nađpal, Jelena D; Lesjak, Marija M; Mrkonjić, Zorica O; Majkić, Tatjana M; Četojević-Simin, Dragana D; Mimica-Dukić, Neda M; Beara, Ivana N

2018-02-15

The aim of the present study was investigation of the phenolic profile, ascorbic acid content, antioxidant, anti-acetylcholinesterase, anti-inflammatory and cytotoxic activity of rose hips and the preserves (purée and jam) of three insufficiently examined Rosa species: Rosa dumalis Bechst., R. dumetorum Thuill. and R. sempervirens L. The liquid chromatography-tandem mass spectrometry analysis resulted in quantification of 14 of the 45 phenolic compounds examined, with ellagic acid as the most dominant. Notable antioxidant activity of all three species was confirmed through several assays. Moderate inhibition of acetylcholinesterase by extracts of all investigated Rosa species was observed. Several extracts of examined Rosa species demonstrated inhibition potency towards production of some monitored eicosanoids in cyclooxygenase-1 and 12-lipoxygenase pathways. Two R. sempervirens extracts exerted cytotoxic activity against HeLa and HT-29 cell lines, but were inactive towards MRC-5 and MCF7. The results support the potential of these rose hips as food with health-promoting properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative study of biological activities and phytochemical composition of two rose hips and their preserves: Rosa canina L. and Rosa arvensis Huds.

PubMed

Nađpal, Jelena D; Lesjak, Marija M; Šibul, Filip S; Anačkov, Goran T; Četojević-Simin, Dragana D; Mimica-Dukić, Neda M; Beara, Ivana N

2016-02-01

The aim of this study was to compare phenolic profile, vitamin C content, antioxidant, anti-inflammatory and cytotoxic activity of rose hips and the preserves (purée and jam) of two Rosa species: renowned Rosa canina L. and unexplored Rosa arvensis Huds. The liquid chromatography-tandem mass spectrometry analysis of 45 phenolics resulted in quantification of 14 compounds, with quercitrin, gallic and protocatechuic acids as the most dominant. High antioxidant potential of R. canina and a moderate activity of R. arvensis extracts were determined through several assays. Purée of both species and methanol extract of air-dried R. canina hips showed some anti-inflammatory (cyclooxygenase-1 and 12-lipooxygense inhibition potency) activity. Purée of R. canina exerted cytotoxic activity only against the HeLa cell line among several others (HeLa, MCF7, HT-29 and MRC-5). The presented results support traditional use of rose hips and their fruit preserves as food with health and nutritional benefits. Copyright © 2015 Elsevier Ltd. All rights reserved.

Strain-level genetic diversity of Methylophaga nitratireducenticrescens confers plasticity to denitrification capacity in a methylotrophic marine denitrifying biofilm.

PubMed

Geoffroy, Valérie; Payette, Geneviève; Mauffrey, Florian; Lestin, Livie; Constant, Philippe; Villemur, Richard

2018-01-01

The biofilm of a methanol-fed, fluidized denitrification system treating a marine effluent is composed of multi-species microorganisms, among which Hyphomicrobium nitrativorans NL23 and Methylophaga nitratireducenticrescens JAM1 are the principal bacteria involved in the denitrifying activities. Strain NL23 can carry complete nitrate (NO[Formula: see text]) reduction to N 2 , whereas strain JAM1 can perform 3 out of the 4 reduction steps. A small proportion of other denitrifiers exists in the biofilm, suggesting the potential plasticity of the biofilm in adapting to environmental changes. Here, we report the acclimation of the denitrifying biofilm from continuous operating mode to batch operating mode, and the isolation and characterization from the acclimated biofilm of a new denitrifying bacterial strain, named GP59. The denitrifying biofilm was batch-cultured under anoxic conditions. The acclimated biofilm was plated on Methylophaga specific medium to isolate denitrifying Methylophaga isolates. Planktonic cultures of strains GP59 and JAM1 were performed, and the growth and the dynamics of NO[Formula: see text], nitrite (NO[Formula: see text]) and N 2 O were determined. The genomes of strains GP59 and JAM1 were sequenced and compared. The transcriptomes of strains GP59 and JAM1 were derived from anoxic cultures. During batch cultures of the biofilm, we observed the disappearance of H. nitrativorans NL23 without affecting the denitrification performance. From the acclimated biofilm, we isolated strain GP59 that can perform, like H. nitrativorans NL23, the complete denitrification pathway. The GP59 cell concentration in the acclimated biofilm was 2-3 orders of magnitude higher than M. nitratireducenticrescens JAM1 and H. nitrativorans NL23. Genome analyses revealed that strain GP59 belongs to the species M. nitratireducenticrescens . The GP59 genome shares more than 85% of its coding sequences with those of strain JAM1. Based on transcriptomic analyses of anoxic cultures, most of these common genes in strain GP59 were expressed at similar level than their counterparts in strain JAM1. In contrast to strain JAM1, strain GP59 cannot reduce NO[Formula: see text] under oxic culture conditions, and has a 24-h lag time before growth and NO[Formula: see text] reduction start to occur in anoxic cultures, suggesting that both strains regulate differently the expression of their denitrification genes. Strain GP59 has the ability to reduce NO[Formula: see text] as it carries a gene encoding a NirK-type NO[Formula: see text] reductase. Based on the CRISPR sequences, strain GP59 did not emerge from strain JAM1 during the biofilm batch cultures but rather was present in the original biofilm and was enriched during this process. These results reinforce the unique trait of the species M. nitratireducenticrescens among the Methylophaga genus as facultative anaerobic bacterium. These findings also showed the plasticity of denitrifying population of the biofilm in adapting to anoxic marine environments of the bioreactor.

Physical-scale models of engineered log jams in rivers

USDA-ARS?s Scientific Manuscript database

Stream restoration and river engineering projects are employing engineered log jams increasingly for stabilization and in-stream improvements. To further advance the design of these structures and their morphodynamic effects on corridors, the basis for physical-scale models of rivers with engineere...

Jamming Signal Reduction in Spread Spectrum Systems.

DTIC Science & Technology

1979-04-26

the addition of an appropriate equalizer netowrk . The original signal and the estimate of the jamming signal are matched and added by a resistor...ADDRESS(SI different from Controllln~ OWce) IS. SECURITY CLASS. (of this report) Unclassified IS.. OECLASSIFICATION /DOWNGRAD IHO SCHEDULE $6. DISTRIB

Cavity method for force transmission in jammed disordered packings of hard particles.

PubMed

Bo, Lin; Mari, Romain; Song, Chaoming; Makse, Hernán A

2014-10-07

The force distribution of jammed disordered packings has always been considered a central object in the physics of granular materials. However, many of its features are poorly understood. In particular, analytic relations to other key macroscopic properties of jammed matter, such as the contact network and its coordination number, are still lacking. Here we develop a mean-field theory for this problem, based on the consideration of the contact network as a random graph where the force transmission becomes a constraint satisfaction problem. We can thus use the cavity method developed in the past few decades within the statistical physics of spin glasses and hard computer science problems. This method allows us to compute the force distribution P(f) for random packings of hard particles of any shape, with or without friction. We find a new signature of jamming in the small force behavior P(f) ∼ f(θ), whose exponent has attracted recent active interest: we find a finite value for P(f = 0), along with θ = 0. Furthermore, we relate the force distribution to a lower bound of the average coordination number z[combining macron](μ) of jammed packings of frictional spheres with coefficient μ. This bridges the gap between the two known isostatic limits z[combining macron]c (μ = 0) = 2D (in dimension D) and z[combining macron]c(μ → ∞) = D + 1 by extending the naive Maxwell's counting argument to frictional spheres. The theoretical framework describes different types of systems, such as non-spherical objects in arbitrary dimensions, providing a common mean-field scenario to investigate force transmission, contact networks and coordination numbers of jammed disordered packings.

Coordination of self-renewal in glioblastoma by integration of adhesion and microRNA signaling.

PubMed

Alvarado, Alvaro G; Turaga, Soumya M; Sathyan, Pratheesh; Mulkearns-Hubert, Erin E; Otvos, Balint; Silver, Daniel J; Hale, James S; Flavahan, William A; Zinn, Pascal O; Sinyuk, Maksim; Li, Meizhang; Guda, Maheedhara R; Velpula, Kiran K; Tsung, Andrew J; Nakano, Ichiro; Vogelbaum, Michael A; Majumder, Sadhan; Rich, Jeremy N; Lathia, Justin D

2016-05-01

Cancer stem cells (CSCs) provide an additional layer of complexity for tumor models and targets for therapeutic development. The balance between CSC self-renewal and differentiation is driven by niche components including adhesion, which is a hallmark of stemness. While studies have demonstrated that the reduction of adhesion molecules, such as integrins and junctional adhesion molecule-A (JAM-A), decreases CSC maintenance. The molecular circuitry underlying these interactions has yet to be resolved. MicroRNA screening predicted that microRNA-145 (miR-145) would bind to JAM-A. JAM-A overexpression in CSCs was evaluated both in vitro (proliferation and self-renewal) and in vivo (intracranial tumor initiation). miR-145 introduction into CSCs was similarly assessed in vitro. Additionally, The Cancer Genome Atlas dataset was evaluated for expression levels of miR-145 and overall survival of the different molecular groups. Using patient-derived glioblastoma CSCs, we confirmed that JAM-A is suppressed by miR-145. CSCs expressed low levels of miR-145, and its introduction decreased self-renewal through reductions in AKT signaling and stem cell marker (SOX2, OCT4, and NANOG) expression; JAM-A overexpression rescued these effects. These findings were predictive of patient survival, with a JAM-A/miR-145 signature robustly predicting poor patient prognosis. Our results link CSC-specific niche signaling to a microRNA regulatory network that is altered in glioblastoma and can be targeted to attenuate CSC self-renewal. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Traffic Vehicle Counting in Jam Flow Conditions Using Low-Cost and Energy-Efficient Wireless Magnetic Sensors.

PubMed

Bao, Xu; Li, Haijian; Xu, Dongwei; Jia, Limin; Ran, Bin; Rong, Jian

2016-11-06

The jam flow condition is one of the main traffic states in traffic flow theory and the most difficult state for sectional traffic information acquisition. Since traffic information acquisition is the basis for the application of an intelligent transportation system, research on traffic vehicle counting methods for the jam flow conditions has been worthwhile. A low-cost and energy-efficient type of multi-function wireless traffic magnetic sensor was designed and developed. Several advantages of the traffic magnetic sensor are that it is suitable for large-scale deployment and time-sustainable detection for traffic information acquisition. Based on the traffic magnetic sensor, a basic vehicle detection algorithm (DWVDA) with less computational complexity was introduced for vehicle counting in low traffic volume conditions. To improve the detection performance in jam flow conditions with a "tailgating effect" between front vehicles and rear vehicles, an improved vehicle detection algorithm (SA-DWVDA) was proposed and applied in field traffic environments. By deploying traffic magnetic sensor nodes in field traffic scenarios, two field experiments were conducted to test and verify the DWVDA and the SA-DWVDA algorithms. The experimental results have shown that both DWVDA and the SA-DWVDA algorithms yield a satisfactory performance in low traffic volume conditions (scenario I) and both of their mean absolute percent errors are less than 1% in this scenario. However, for jam flow conditions with heavy traffic volumes (scenario II), the SA-DWVDA was proven to achieve better results, and the mean absolute percent error of the SA-DWVDA is 2.54% with corresponding results of the DWVDA 7.07%. The results conclude that the proposed SA-DWVDA can implement efficient and accurate vehicle detection in jam flow conditions and can be employed in field traffic environments.

Innovative Engagement with NASA Data: Best Practices in Hosting a Space-Themed Game Jam Event

NASA Astrophysics Data System (ADS)

Mader, M. M.

2015-12-01

Planetary mission milestones provide key opportunities to engage the public in the day to day work and showcase the value, wonder, and innovative technologies of planetary exploration. The Royal Ontario Museum (ROM), Canada, is designing unique experiences that will allow new audiences to relate to planetary mission results, through direct interaction with planetary materials and data. Through co-creation and collaboration, we aim to encourage STEM and STEAM learning through interactive programs that are interest driven by the participants. Based on these principles, the ROM, in collaboration with the University of Toronto, is hosting a Game Jam event (see http://www.rom.on.ca/en/activities-programs/programs/game-jam). A Game Jam invites creative, motivated, and inspired game developers to work in a collaborative environment over the course of 3 days to create games linked to a theme. This year's theme is "Space Rocks". Video games, fuelled by actual mission data, capture public interest in space and science in a unique and powerful way, giving us new insight into the real challenges we have on Earth and in space. The ROM Game Jam will allow 100 game developers to draw inspiration from our collection of over 100,000 rocks, minerals, and gems, including over 500 martian, lunar, and asteroidal meteorites. Participants will learn about the history of these specimens directly from ROM experts. NASA datasets related to our collection will be highlighted and curated for this event. The games produced during the Game Jam will live on and be featured online and at numerous ROM events throughout the year. Our presentation will highlight lessons learned from this experience, best practices, and future plans.

Traffic Vehicle Counting in Jam Flow Conditions Using Low-Cost and Energy-Efficient Wireless Magnetic Sensors

PubMed Central

Bao, Xu; Li, Haijian; Xu, Dongwei; Jia, Limin; Ran, Bin; Rong, Jian

2016-01-01

The jam flow condition is one of the main traffic states in traffic flow theory and the most difficult state for sectional traffic information acquisition. Since traffic information acquisition is the basis for the application of an intelligent transportation system, research on traffic vehicle counting methods for the jam flow conditions has been worthwhile. A low-cost and energy-efficient type of multi-function wireless traffic magnetic sensor was designed and developed. Several advantages of the traffic magnetic sensor are that it is suitable for large-scale deployment and time-sustainable detection for traffic information acquisition. Based on the traffic magnetic sensor, a basic vehicle detection algorithm (DWVDA) with less computational complexity was introduced for vehicle counting in low traffic volume conditions. To improve the detection performance in jam flow conditions with a “tailgating effect” between front vehicles and rear vehicles, an improved vehicle detection algorithm (SA-DWVDA) was proposed and applied in field traffic environments. By deploying traffic magnetic sensor nodes in field traffic scenarios, two field experiments were conducted to test and verify the DWVDA and the SA-DWVDA algorithms. The experimental results have shown that both DWVDA and the SA-DWVDA algorithms yield a satisfactory performance in low traffic volume conditions (scenario I) and both of their mean absolute percent errors are less than 1% in this scenario. However, for jam flow conditions with heavy traffic volumes (scenario II), the SA-DWVDA was proven to achieve better results, and the mean absolute percent error of the SA-DWVDA is 2.54% with corresponding results of the DWVDA 7.07%. The results conclude that the proposed SA-DWVDA can implement efficient and accurate vehicle detection in jam flow conditions and can be employed in field traffic environments. PMID:27827974

A Comparative Study of Acousto-Optic Time-Integrating Correlators for Adaptive Jamming Cancellation

DTIC Science & Technology

1997-10-01

This final report presents a comparative study of the space-integrating and time-integrating configurations of an acousto - optic correlator...systematically evaluate all existing acousto - optic correlator architectures and to determine which would be most suitable for adaptive jamming

Cell jammers, GPS jammers, and other jamming devices.

DOT National Transportation Integrated Search

2012-10-15

We caution consumers that it is against the law to use a cell or GPS jammer or any other type of device that blocks, : jams or interferes with authorized communications, as well as to import, advertise, sell, or ship such a device. The : FCC Enforcem...

Long-Term Storage Studies on Dehydrated Ration Items and Food Packets

DTIC Science & Technology

1976-06-01

and onions, bacon, corn, fruit salad, steamed fruitcake, chocolate nut bread, plums, rolled oats, raspberry and strawberry Jams , and one brand of... strawberry jam , biscuit spread, and canned peachsa ware unacceptable; scores for chocolate bera, beef and apaghetti, chicksn soup, canned plums

15. (Credit JAM) Aerial view of the McNeil Street Station, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

15. (Credit JAM) Aerial view of the McNeil Street Station, date unknown, but comparatively recent. Note the new filter house to the left of the settling basins. - McNeil Street Pumping Station, McNeil Street & Cross Bayou, Shreveport, Caddo Parish, LA

Saddle-node bifurcation to jammed state for quasi-one-dimensional counter-chemotactic flow.

PubMed

Fujii, Masashi; Awazu, Akinori; Nishimori, Hiraku

2010-07-01

The transition of a counter-chemotactic particle flow from a free-flow state to a jammed state in a quasi-one-dimensional path is investigated. One of the characteristic features of such a flow is that the constituent particles spontaneously form a cluster that blocks the path, called a path-blocking cluster (PBC), and causes a jammed state when the particle density is greater than a threshold value. Near the threshold value, the PBC occasionally collapses on itself to recover the free flow. In other words, the time evolution of the size of the PBC governs the flux of a counter-chemotactic flow. In this Rapid Communication, on the basis of numerical results of a stochastic cellular automata (SCA) model, we introduce a Langevin equation model for the size evolution of the PBC that reproduces the qualitative characteristics of the SCA model. The results suggest that the emergence of the jammed state in a quasi-one-dimensional counterflow is caused by a saddle-node bifurcation.

Stability of micronutrients and phytochemicals of grapefruit jam as affected by the obtention process.

PubMed

Igual, M; García-Martínez, E; Camacho, M M; Martínez-Navarrete, N

2016-04-01

Fruits are widely revered for their micronutrient properties. They serve as a primary source of vitamins and minerals as well as of natural phytonutrients with antioxidant properties. Jam constitutes an interesting way to preserve fruit. Traditionally, this product is obtained by intense heat treatment that may cause irreversible loss of these bioactive compounds responsible for the health-related properties of fruits. In this work, different grapefruit jams obtained by conventional, osmotic dehydration (OD) without thermal treatment and/or microwave (MW) techniques were compared in terms of their vitamin, organic acid and phytochemical content and their stability through three months of storage. If compared with heating, osmotic treatments lead to a greater loss of organic acids and vitamin C during both processing and storage. MW treatments permit jam to be obtained which has a similar nutritional and functional value than that obtained when using a conventional heating method, but in a much shorter time. © The Author(s) 2015.

Self-organized criticality in asymmetric exclusion model with noise for freeway traffic

NASA Astrophysics Data System (ADS)

Nagatani, Takashi

1995-02-01

The one-dimensional asymmetric simple-exclusion model with open boundaries for parallel update is extended to take into account temporary stopping of particles. The model presents the traffic flow on a highway with temporary deceleration of cars. Introducing temporary stopping into the asymmetric simple-exclusion model drives the system asymptotically into a steady state exhibiting a self-organized criticality. In the self-organized critical state, start-stop waves (or traffic jams) appear with various sizes (or lifetimes). The typical interval < s>between consecutive jams scales as < s> ≃ Lv with v = 0.51 ± 0.05 where L is the system size. It is shown that the cumulative jam-interval distribution Ns( L) satisfies the finite-size scaling form ( Ns( L) ≃ L- vf( s/ Lv). Also, the typical lifetime ≃ Lv‧ with v‧ = 0.52 ± 0.05. The cumulative distribution Nm( L) of lifetimes satisfies the finite-size scaling form Nm( L)≃ L-1g( m/ Lv‧).

ECCM Scheme against Interrupted Sampling Repeater Jammer Based on Parameter-Adjusted Waveform Design

PubMed Central

Wei, Zhenhua; Peng, Bo; Shen, Rui

2018-01-01

Interrupted sampling repeater jamming (ISRJ) is an effective way of deceiving coherent radar sensors, especially for linear frequency modulated (LFM) radar. In this paper, for a simplified scenario with a single jammer, we propose a dynamic electronic counter-counter measure (ECCM) scheme based on jammer parameter estimation and transmitted signal design. Firstly, the LFM waveform is transmitted to estimate the main jamming parameters by investigating the discontinuousness of the ISRJ’s time-frequency (TF) characteristics. Then, a parameter-adjusted intra-pulse frequency coded signal, whose ISRJ signal after matched filtering only forms a single false target, is designed adaptively according to the estimated parameters, i.e., sampling interval, sampling duration and repeater times. Ultimately, for typical jamming scenes with different jamming signal ratio (JSR) and duty cycle, we propose two particular ISRJ suppression approaches. Simulation results validate the effective performance of the proposed scheme for countering the ISRJ, and the trade-off relationship between the two approaches is demonstrated. PMID:29642508

Reconfigurable Control Design for the Full X-33 Flight Envelope

NASA Technical Reports Server (NTRS)

Cotting, M. Christopher; Burken, John J.

2001-01-01

A reconfigurable control law for the full X-33 flight envelope has been designed to accommodate a failed control surface and redistribute the control effort among the remaining working surfaces to retain satisfactory stability and performance. An offline nonlinear constrained optimization approach has been used for the X-33 reconfigurable control design method. Using a nonlinear, six-degree-of-freedom simulation, three example failures are evaluated: ascent with a left body flap jammed at maximum deflection; entry with a right inboard elevon jammed at maximum deflection; and landing with a left rudder jammed at maximum deflection. Failure detection and identification are accomplished in the actuator controller. Failure response comparisons between the nominal control mixer and the reconfigurable control subsystem (mixer) show the benefits of reconfiguration. Single aerosurface jamming failures are considered. The cases evaluated are representative of the study conducted to prove the adequate and safe performance of the reconfigurable control mixer throughout the full flight envelope. The X-33 flight control system incorporates reconfigurable flight control in the existing baseline system.

Jamming criticality revealed by removing localized buckling excitations.

PubMed

Charbonneau, Patrick; Corwin, Eric I; Parisi, Giorgio; Zamponi, Francesco

2015-03-27

Recent theoretical advances offer an exact, first-principles theory of jamming criticality in infinite dimension as well as universal scaling relations between critical exponents in all dimensions. For packings of frictionless spheres near the jamming transition, these advances predict that nontrivial power-law exponents characterize the critical distribution of (i) small interparticle gaps and (ii) weak contact forces, both of which are crucial for mechanical stability. The scaling of the interparticle gaps is known to be constant in all spatial dimensions d-including the physically relevant d=2 and 3, but the value of the weak force exponent remains the object of debate and confusion. Here, we resolve this ambiguity by numerical simulations. We construct isostatic jammed packings with extremely high accuracy, and introduce a simple criterion to separate the contribution of particles that give rise to localized buckling excitations, i.e., bucklers, from the others. This analysis reveals the remarkable dimensional robustness of mean-field marginality and its associated criticality.

Tracking antioxidant properties and color changes in low-sugar bilberry jam as effect of processing, storage and pectin concentration

PubMed Central

2012-01-01

Background Recently, an increased interest in the identification of valuable possibilities for preserving the antioxidant properties of products obtained by thermal processing of fruits rich in bioactive compounds can be noticed. In this regard, an extensive analysis is necessary in terms of thermal processed products behavior in relation to various factors. The purpose of the present study was to assess the effect which processing and storage at 20°C has on the antioxidant properties and color quality of low-sugar bilberry jam with different low-methoxyl pectin (LMP) concentrations. Results For all measured parameters, it should be noted that thermal processing induced significant alterations reported to the values registered for fresh fruit. Most important losses due to thermal processing were recorded for total monomeric anthocyanins (TMA) (81-84%), followed by L-ascorbic acid (L-AsAc) content (53-58%), total phenolics (TP) content (42-51%) and FRAP (ferric reducing antioxidant power) values (36-47%). Moreover, depreciation of the investigated compounds occurred during storage at 20°C. Jam storage for 7 months resulted in severe losses in TMA content in the range 58-72% from the value recorded one day after processing. This coincided with marked increases in polymeric color percent of these products after 7 months of storage. Also, bilberry jam storage for 7 months resulted in a decrease in L-AsAc content of 40-53% from the value recorded one day after processing, 41-57% in TP content and 33-46% from the value recorded one day after processing for FRAP values. By decreasing of LMP concentration in the jam recipe from 1 to 0.3% there has been an increase in losses of investigated compounds. Conclusion Overall, the results indicated that bilberry jams can also represent a good source of antioxidant compounds, although compared to the fruit, important losses seem to occur. Practical application of this work is that this kind of information will be very useful in optimizing the jam processing technology and storage conditions, in order to improve the quality of these products. PMID:22248151

All-optical liquid crystal spatial light modulators

NASA Astrophysics Data System (ADS)

Tabiryan, Nelson; Grozhik, Vladimir; Khoo, Iam Choon; Nersisyan, Sarik R.; Serak, Svetlana

2003-12-01

Nonlinear optical processes in liquid crystals (LC) can be used for construction of all-optical spatial light modulators (SLM) where the photosensitivity and phase modulating functions are integrated into a single layer of an LC-material. Such spatial light integrated modulators (SLIMs) cost only a fraction of the conventional LC-SLM and can be used with high power laser radiation due to high transparency of LC materials and absence of light absorbing electrodes on the substrates of the LC-cell constituting the SLIM. Recent development of LC materials the photosensitivity of which is comparable to that of semiconductors has led to using SLIM in schemes of optical anti-jamming, sensor protection, and image processing. All-optical processes add remarkable versatility to the operation of SLIM harnessing the wealth inherent to light-matter interaction phenomena.

Shearing Low-frictional 3D Granular Materials

NASA Astrophysics Data System (ADS)

Chen, David; Zheng, Hu; Behringer, Robert

Shear jamming occurs in frictional particles over a range of packing fractions, from random loose to random dense. Simulations show shear jamming for frictionless spheres, but over a vanishing range as the system size grows. We use packings of submerged and diffractive index-matched hydrogel particles to determine the shear-induced microscopic response of 3D, low-frictional granular systems near jamming, bridging the gap between frictionless and low friction packings. We visualize the particles by a laser scanning technique, and we track particle motion along with their interparticle contact forces from its 3D-reconstructions. NSF-DMF-1206351, NASA NNX15AD38G, William M. Keck Foundation, and DARPA.

PathJam: a new service for integrating biological pathway information.

PubMed

Glez-Peña, Daniel; Reboiro-Jato, Miguel; Domínguez, Rubén; Gómez-López, Gonzalo; Pisano, David G; Fdez-Riverola, Florentino

2010-10-28

Biological pathways are crucial to much of the scientific research today including the study of specific biological processes related with human diseases. PathJam is a new comprehensive and freely accessible web-server application integrating scattered human pathway annotation from several public sources. The tool has been designed for both (i) being intuitive for wet-lab users providing statistical enrichment analysis of pathway annotations and (ii) giving support to the development of new integrative pathway applications. PathJam’s unique features and advantages include interactive graphs linking pathways and genes of interest, downloadable results in fully compatible formats, GSEA compatible output files and a standardized RESTful API.

The Classroom Traffic Jam

ERIC Educational Resources Information Center

Edwards, Arthur W.

1977-01-01

The importance of energy conservation is developed in this simulation. Children draw an automobile and then are asked to drive it through the classroom roadways. When a traffic jam results, students offer ways to eliminate it. The importance of mass transportation and car pools is stressed by the teacher. (MA)

Bats adjust their pulse emission rates with swarm size in the field.

PubMed

Lin, Yuan; Abaid, Nicole; Müller, Rolf

2016-12-01

Flying in swarms, e.g., when exiting a cave, could pose a problem to bats that use an active biosonar system because the animals could risk jamming each other's biosonar signals. Studies from current literature have found different results with regard to whether bats reduce or increase emission rate in the presence of jamming ultrasound. In the present work, the number of Eastern bent-wing bats (Miniopterus fuliginosus) that were flying inside a cave during emergence was estimated along with the number of signal pulses recorded. Over the range of average bat numbers present in the recording (0 to 14 bats), the average number of detected pulses per bat increased with the average number of bats. The result was interpreted as an indication that the Eastern bent-wing bats increased their emission rate and/or pulse amplitude with swarm size on average. This finding could be explained by the hypothesis that the bats might not suffer from substantial jamming probabilities under the observed density regimes, so jamming might not have been a limiting factor for their emissions. When jamming did occur, the bats could avoid it through changing the pulse amplitude and other pulse properties such as duration or frequency, which has been suggested by other studies. More importantly, the increased biosonar activities may have addressed a collision-avoidance challenge that was posed by the increased swarm size.

A theoretical framework for jamming in confluent biological tissues

NASA Astrophysics Data System (ADS)

Manning, M. Lisa

2015-03-01

For important biological functions such as wound healing, embryonic development, and cancer tumorogenesis, cells must initially rearrange and move over relatively large distances, like a liquid. Subsequently, these same tissues must undergo buckling and support shear stresses, like a solid. Our work suggests that biological tissues can accommodate these disparate requirements because the tissues are close to glass or jamming transition. While recent self propelled particle models generically predict a glass/jamming transition that is driven by packing density φ and happens at some critical φc less than unity, many biological tissues that are confluent with no gaps between cells appear to undergo a jamming transition at a constant density (φ = 1). I will discuss a new theoretical framework for predicting energy barriers and rates of cell migration in 2D tissue monolayers, and show that this model predicts a novel type of rigidity transition, which takes place at constant φ = 1 and depends only on single cell properties such as cell-cell adhesion, cortical tension and cell elasticity. This model additionally predicts that an experimentally observable parameter, the ratio between a cell's perimeter and the square root of its cross-sectional area, attains a specific, critical value at the jamming transition. We show that this prediction is precisely realized in primary epithelial cultures from human patients, with implications for asthma pathology.

System-spanning dynamically jammed region in response to impact of cornstarch and water suspensions

NASA Astrophysics Data System (ADS)

Allen, Benjamin; Sokol, Benjamin; Mukhopadhyay, Shomeek; Maharjan, Rijan; Brown, Eric

2018-05-01

We experimentally characterize the structure of concentrated suspensions of cornstarch and water in response to impact. Using surface imaging and particle tracking at the boundary opposite the impactor, we observed that a visible structure and particle flow at the boundary occur with a delay after impact. We show the delay time is about the same time as the strong stress response, confirming that the strong stress response results from deformation of the dynamically jammed structure once it spans between the impactor and a solid boundary. A characterization of this strong stress response is reported in a companion paper [Maharjan, Mukhopadhyay, Allen, Storz, and Brown, Phys. Rev. E 97, 052602 (2018), 10.1103/PhysRevE.97.052602]. We observed particle flow in the outer part of the dynamically jammed region at the bottom boundary, with a net transverse displacement of up to about 5% of the impactor displacement, indicating shear at the boundary. Direct imaging of the surface of the outer part of the dynamically jammed region reveals a change in surface structure that appears the same as the result of dilation in other cornstarch suspensions. Imaging also reveals cracks, like a brittle solid. These observations suggest the dynamically jammed structure can temporarily support stress according to an effective modulus, like a soil or dense granular material, along a network of frictional contacts between the impactor and solid boundary.

Geofilum rubicundum gen. nov., sp. nov., isolated from deep subseafloor sediment.

PubMed

Miyazaki, Masayuki; Koide, Osamu; Kobayashi, Tohru; Mori, Kozue; Shimamura, Shigeru; Nunoura, Takuro; Imachi, Hiroyuki; Inagaki, Fumio; Nagahama, Takahiko; Nogi, Yuichi; Deguchi, Shigeru; Takai, Ken

2012-05-01

A novel, facultatively anaerobic bacterium (strain JAM-BA0501(T)) was isolated from a deep subseafloor sediment sample at a depth of 247 m below seafloor off the Shimokita Peninsula of Japan in the north-western Pacific Ocean (Site C9001, 1180 m water depth). Cells of strain JAM-BA0501(T) were gram-negative, filamentous, non-spore-forming and motile on solid medium by gliding. Phylogenetic analysis based on the 16S rRNA gene sequence of strain JAM-BA0501(T) indicated a distant relationship to strains representing genera within the order Bacteroidales, such as Alkaliflexus imshenetskii Z-7010(T) (91.1 % similarity), Marinilabilia salmonicolor ATCC 19041(T) (86.2 %) and Anaerophaga thermohalophila Fru22(T) (89.3 %). The new isolate produced isoprenoid quinones with menaquinone MK-7 as the major component, and the predominant fatty acids were iso-C(15 : 0) and anteiso-C(15 : 0). The DNA G+C content of the isolate was 42.9 mol%. Based on its taxonomic distinctiveness, strain JAM-BA0501(T) is considered to represent a novel species of a new genus within the family Marinilabiliaceae, for which the name Geofilum rubicundum gen. nov., sp. nov. is proposed. The type strain of Geofilum rubicundum is JAM-BA0501(T) ( = JCM 15548(T)  = NCIMB 14482(T)).

The ATLAS3D project - XX. Mass-size and mass-σ distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function

NASA Astrophysics Data System (ADS)

Cappellari, Michele; McDermid, Richard M.; Alatalo, Katherine; Blitz, Leo; Bois, Maxime; Bournaud, Frédéric; Bureau, M.; Crocker, Alison F.; Davies, Roger L.; Davis, Timothy A.; de Zeeuw, P. T.; Duc, Pierre-Alain; Emsellem, Eric; Khochfar, Sadegh; Krajnović, Davor; Kuntschner, Harald; Morganti, Raffaella; Naab, Thorsten; Oosterloo, Tom; Sarzi, Marc; Scott, Nicholas; Serra, Paolo; Weijmans, Anne-Marie; Young, Lisa M.

2013-07-01

In the companion Paper XV of this series, we derive accurate total mass-to-light ratios (M/L)_JAM≈ (M/L)({r}= {R_e}) within a sphere of radius r= {R_e} centred on the galaxy, as well as stellar (M/L)stars (with the dark matter removed) for the volume-limited and nearly mass-selected (stellar mass M_star ≳ 6× 10^9 { M_{⊙}}) ATLAS3D sample of 260 early-type galaxies (ETGs, ellipticals Es and lenticulars S0s). Here, we use those parameters to study the two orthogonal projections ({M_JAM}, {σ _e}) and ({M_JAM}, {R_e^maj}) of the thin Mass Plane (MP) ({M_JAM}, {σ _e}, {R_e^maj}) which describes the distribution of the galaxy population, where {M_JAM}≡ L× (M/L)_JAM≈ M_star. The distribution of galaxy properties on both projections of the MP is characterized by: (i) the same zone of exclusion (ZOE), which can be transformed from one projection to the other using the scalar virial equation. The ZOE is roughly described by two power laws, joined by a break at a characteristic mass {M_JAM}≈ 3× 10^{10} { M_{⊙}}, which corresponds to the minimum Re and maximum stellar density. This results in a break in the mean {M_JAM}-{σ _e} relation with trends {M_JAM}∝ σ _e^{2.3} and {M_JAM}∝ σ _e^{4.7} at small and large σe, respectively; (ii) a characteristic mass {M_JAM}≈ 2× 10^{11} { M_{⊙}} which separates a population dominated by flat fast rotator with discs and spiral galaxies at lower masses, from one dominated by quite round slow rotators at larger masses; (iii) below that mass the distribution of ETGs' properties on the two projections of the MP tends to be constant along lines of roughly constant σe, or equivalently along lines with {R_e^maj}∝ {M_JAM}, respectively (or even better parallel to the ZOE: {R_e^maj}∝ M_JAM^{0.75}); (iv) it forms a continuous and parallel sequence with the distribution of spiral galaxies; (v) at even lower masses, the distribution of fast-rotator ETGs and late spirals naturally extends to that of dwarf ETGs (Sph) and dwarf irregulars (Im), respectively. We use dynamical models to analyse our kinematic maps. We show that σe traces the bulge fraction, which appears to be the main driver for the observed trends in the dynamical (M/L)JAM and in indicators of the (M/L)pop of the stellar population like Hβ and colour, as well as in the molecular gas fraction. A similar variation along contours of σe is also observed for the mass normalization of the stellar initial mass function (IMF), which was recently shown to vary systematically within the ETGs' population. Our preferred relation has the form log _{10} [(M/L)_stars/(M/L)_Salp]=a+b× log _{10}({σ _e}/130 {km s^{-1}}) with a = -0.12 ± 0.01 and b = 0.35 ± 0.06. Unless there are major flaws in all stellar population models, this trend implies a transition of the mean IMF from Kroupa to Salpeter in the interval log _{10}({σ _e}/{km s}^{-1})≈ 1.9-2.5 (or {σ _e}≈ 90-290 km s-1), with a smooth variation in between, consistently with what was shown in Cappellari et al. The observed distribution of galaxy properties on the MP provides a clean and novel view for a number of previously reported trends, which constitute special two-dimensional projections of the more general four-dimensional parameters trends on the MP. We interpret it as due to a combination of two main effects: (i) an increase of the bulge fraction, which increases σe, decreases Re, and greatly enhance the likelihood for a galaxy to have its star formation quenched, and (ii) dry merging, increasing galaxy mass and Re by moving galaxies along lines of roughly constant σe (or steeper), while leaving the population nearly unchanged.

Modeling no-jam traffic in ant trails: a pheromone-controlled approach

NASA Astrophysics Data System (ADS)

Guo, Ning; Hu, Mao-Bin; Jiang, Rui; Ding, Jianxun; Ling, Xiang

2018-05-01

The experiment in John et al (2009 Phys. Rev. Lett. 102 108001) shows that when ants move in a single-file trail, no jam emerges even at very high densities. We propose a self-propelled model of ant traffic to reproduce the fundamental diagram without a jammed branch. In this model, ants can adjust their desired velocities actively by perceiving pheromone concentration near the front of the trail. Moreover, ants will bear the repulsive force when they have physical contact with neighbors. The velocity in the simulation decreases slightly with increasing density, which captures the main feature observed in the experiment. Distributions of velocity and distance headway basically also conform to the experimental ones.

Food Byproducts as a New and Cheap Source of Bioactive Compounds: Lignans with Antioxidant and Anti-inflammatory Properties from Crataegus pinnatifida Seeds.

PubMed

Huang, Xiao-Xiao; Bai, Ming; Zhou, Le; Lou, Li-Li; Liu, Qing-Bo; Zhang, Yan; Li, Ling-Zhi; Song, Shao-Jiang

2015-08-19

During the process of manufacturing hawthorn (Crataegus pinnatifida) juice and jam, a significant quantity of byproducts (leaves, seeds) is generated. The antioxidant and anti-inflammatory bioassay-guided fractionation of the extract of hawthorn seeds has led to the isolation of eight new lignans, hawthornnins A-H (1-8), and seven known analogues (9-15). Their structures were elucidated by spectroscopic techniques, including 1D and 2D NMR and CD spectra. The radical-scavenging effects of all isolated compounds were investigated. 1-6 and 8 showed moderate activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), whereas 1-6 and 14 displayed good 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radical-scavenging activities that were even more potent than that of trolox. In addition, all isolates were evaluated for their anti-inflammatory activities by detecting the nitric oxide (NO) and tumor necrosis factor α (TNF-α) production by the LPS-induced murine macrophage cell line RAW264.7, and compounds 1-7, 13, and 14 exhibited potent inhibition of NO and TNF-α production. The structure-activity relationships of isolated lignans were also examined, and the results obtained show that C. pinnatifida seeds can be regarded as a potential new and cheap source of antioxidants and inflammation inhibitors.

78 FR 275 - Airworthiness Directives; REIMS Aviation S.A. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-03

... horizontal tail structure, which could cause the elevator pushrod to jam and could result in loss of control... corrected, could lead to failure of a pushrod and consequent jamming of the elevator controls, possibly resulting in loss of control of the aeroplane. For the reasons described above, this AD requires inspection...

Evaluation of Electronic Counter-Countermeasures Training Using Microcomputer-Based Technology: Phase I. Basic Jamming Recognition.

ERIC Educational Resources Information Center

Gardner, Susan G.; Ellis, Burl D.

Seven microcomputer-based training systems with videotape players/monitors were installed to provide electronic counter-countermeasures (ECCM) simulation training, drill and practice, and performance testing for three courses at a fleet combat training center. Narrated videotape presentations of simulated and live jamming followed by a drill and…

Responses of experimental river corridors to engineered log jams

USDA-ARS?s Scientific Manuscript database

Physical models of the Big Sioux River, SD, were constructed to assess the impact on flow, drag, and bed erosion and deposition in response to the installation of two different types of engineered log jams (ELJs). A fixed-bed model focused on flow velocity and forces acting on an instrumented ELJ, a...

Electronic Warfare in Operations

DTIC Science & Technology

2009-02-25

intelligence-related portion of the EW running estimate. Provides input to the restricted frequency list by recommending guarded frequencies. Provides...preparation of the restricted frequency list and issuance of emissions control guidance. Coordinates frequency allotment, assignment, and use... frequency list . Validating and approving or denying cease-jamming requests. Maintaining situational awareness of all jamming-capable systems in the area

Effects of Cyclic Prefix Jamming Versus Noise Jamming in OFDM Signals

DTIC Science & Technology

2011-03-01

is even found in the Bluetooth technology used in something as common as videogame con- trollers. It is now a more universally-accepted standard for...Dec 2009. [Online]. Avail- able: http://www.brighthub.com/electronics/gps/articles/60598.aspx. 8. LTE Product Design, “LTE Benefits v 3.3,” May

Jam Injuries of the Finger: Diagnosis and Management of Injuries to the Interphalangeal Joints Across Multiple Sports and Levels of Experience.

PubMed

Carruthers, Katherine H; Skie, Martin; Jain, Margaret

2016-09-01

Jam injuries of the finger are frequently encountered in general orthopaedic and sports medicine practice. The finger joints in particular are very susceptible to traumatic injury, but in the absence of severe deformity, digital trauma is often downplayed in the hopes of a more rapid return to game play. Articles published from 1966 to 2015 were reviewed to capture historical and current views on the presentation, diagnosis, and treatment of jam injuries in athletes. Clinical review. Level 5. Although jam injuries are frequently grouped together, they represent a host of injuries that can be challenging to differentiate. A thorough knowledge of finger joint anatomy and injury mechanism is critical to perform an appropriate examination, establish an accurate diagnosis, and identify a treatment plan for each patient. Every member of the athletic care team must be aware of the spectrum of digital injuries, including the basic signs present on examination, which may indicate the need for more formal workup. Additionally, preventing injury through athlete education is paramount to athletic care. © 2016 The Author(s).

Microscopic Origins of Shear Jamming for 2D Frictional Grains

NASA Astrophysics Data System (ADS)

Wang, Dong; Ren, Jie; Dijksman, Joshua A.; Zheng, Hu; Behringer, Robert P.

2018-05-01

Shear jamming (SJ) occurs for frictional granular materials with packing fractions ϕ in ϕS<ϕ <ϕJ0, when the material is subject to shear strain γ starting from a force-free state. Here, ϕJμ is the isotropic jamming point for particles with a friction coefficient μ . SJ states have mechanically stable anisotropic force networks, e.g., force chains. Here, we investigate the origins of SJ by considering small-scale structures—trimers and branches—whose response to shear leads to SJ. Trimers are any three grains where the two outer grains contact a center one. Branches occur where three or more quasilinear force chain segments intersect. Certain trimers respond to shear by compressing and bending; bending is a nonlinear symmetry-breaking process that can push particles in the dilation direction faster than the affine dilation. We identify these structures in physical experiments on systems of two-dimensional frictional discs, and verify their role in SJ. Trimer bending and branch creation both increase Z above Ziso≃3 needed for jamming 2D frictional grains, and grow the strong force network, leading to SJ.

Degradation of anthocyanins and anthocyanidins in blueberry jams/stuffed fish.

PubMed

Queiroz, Filipa; Oliveira, Carla; Pinho, Olívia; Ferreira, Isabel M P L V O

2009-11-25

This study examined the effects of cooking on the degradation of anthocyanins and anthocyanidins of blueberries (Vaccinium corymbosum L.) from cultivar Bluecrop. Fruits were used to prepare jams with different degrees Brix and stuffed fish. A systematic evaluation of the degradation of anthocyanins and anthocyanidins of blueberries was performed; for that purpose an HPLC/DAD method was used to determine anthocyanin profile and anthocyanidin contents in fresh and cooked blueberries and in jams. Ten anthocyanins were separated and monitored in methanolic extracts. Of the six common anthocyanidins, four were identified in the hydrolysates, namely, delphinidin, cyanidin, petunidin and malvidin. Percentage of degradation of anthocyanins and anthocyanidins in jams is highly dependent on degrees Brix: 64-76 degrees Brix led to 20-30% degradation, whereas 80 degrees Brix resulted in degradation between 50 and 60%. Percentage of degradation of anthocyanins in whole blueberries cooked in stuffed fish ranged between 45 and 50%, however, for anthocyanidins, the percentage of degradation was significantly lower, between 12 and 30%, indicating that this cooking procedure can preserve anthocyanidin degradation.

Random close packing of polydisperse jammed emulsions

NASA Astrophysics Data System (ADS)

Brujic, Jasna

2010-03-01

Packing problems are everywhere, ranging from oil extraction through porous rocks to grain storage in silos and the compaction of pharmaceutical powders into tablets. At a given density, particulate systems pack into a mechanically stable and amorphous jammed state. Theoretical frameworks have proposed a connection between this jammed state and the glass transition, a thermodynamics of jamming, as well as geometric modeling of random packings. Nevertheless, a simple underlying mechanism for the random assembly of athermal particles, analogous to crystalline ordering, remains unknown. Here we use 3D measurements of polydisperse packings of emulsion droplets to build a simple statistical model in which the complexity of the global packing is distilled into a local stochastic process. From the perspective of a single particle the packing problem is reduced to the random formation of nearest neighbors, followed by a choice of contacts among them. The two key parameters in the model, the available space around a particle and the ratio of contacts to neighbors, are directly obtained from experiments. Remarkably, we demonstrate that this ``granocentric'' view captures the properties of the polydisperse emulsion packing, ranging from the microscopic distributions of nearest neighbors and contacts to local density fluctuations and all the way to the global packing density. Further applications to monodisperse and bidisperse systems quantitatively agree with previously measured trends in global density. This model therefore reveals a general principle of organization for random packing and lays the foundations for a theory of jammed matter.

Climatic effects on ice-jam flooding of the Peace-Athabasca Delta

NASA Astrophysics Data System (ADS)

Beltaos, S.; Prowse, T.; Bonsal, B.; Mackay, R.; Romolo, L.; Pietroniro, A.; Toth, B.

2006-12-01

The Peace-Athabasca Delta (PAD) in northern Alberta is one of the world's largest inland freshwater deltas, home to large populations of waterfowl, muskrat, beaver, and free-ranging wood bison. In recent decades, a paucity of ice-jam flooding in the lower Peace River has resulted in prolonged dry periods and considerable reduction in the area covered by lakes and ponds that provide habitat for aquatic life in the PAD region. Building on previous work that has identified the salient hydro-climatic factors, the frequency of ice-jam floods is considered under present (1961-1990) and future (2070-2099) climatic conditions. The latter are determined using temperature and precipitation output from the Canadian Climate Centre's second-generation Global Climate Model (CGCM2) for two different greenhouse-gas/sulphate emission scenarios. The analysis indicates that the ice season is likely to be reduced by 2-4 weeks, while future ice covers would be slightly thinner than they are at present. More importantly, a large part of the Peace River basin is expected to experience frequent and sustained mid-winter thaws, leading to significant melt and depleted snowpacks in the spring. Using an empirical relationship between ice-jam flood occurrence and size of the spring snowpack, a severe reduction in the frequency of ice-jam flooding is predicted under both future-climate scenarios that were considered. In turn, this trend is likely to accelerate the loss of aquatic habitat in the PAD region. Implications for potential mitigation and adaptation strategies are discussed. Copyright

The glass and jamming transitions in dense granular matter

NASA Astrophysics Data System (ADS)

Coulais, Corentin; Candelier, Raphaël; Dauchot, Olivier

2013-06-01

Everyday life tells us that matter acquires rigidity either when it cools down, like lava flows which turn into solid rocks, or when it is compacted, like tablets simply formed by powder compression. As suggested by these examples, solidification is not the sole privilege of crystals but also happens for disordered media such as glass formers, granular media, foams, emulsions and colloidal suspensions. Fifteen years ago the "Jamming paradigm" emerged to encompass in a unique framework the glass transition and the emergence of yield stress, two challenging issues in modern condensed matter physics. One must realize how bold this proposal was, given that the glass transition is a finite temperature transition governing the dynamical properties of supercooled liquids, while Jamming is essentially a zero temperature, zero external stress and purely geometric transition which occurs when a given packing of particles reaches the maximum compression state above which particles start to overlap. More recently, the observation of remarkable scaling properties on the approach to jamming led to the conjecture that this zero temperature "critical point" could determine the properties of dense particle systems within a region of the parameter space to be determined, which in principle could include thermal and stressed systems. Fifteen years of intense theoretical and experimental work later, what have we learned about Jamming and glassy dynamics? In this paper, we discuss these issues in the light of the experiments we have been conducting with vibrated grains.

The impact of engineered log jams on bed morphology, flow characteristics and habitat diversity under low flow

NASA Astrophysics Data System (ADS)

Ockelford, A.; Crabbe, E.; Crowe Curran, J.; Parsons, D. R.; Shugar, D. H.; Burr, A.; Kennedy, K.; Coe, T.

2017-12-01

Wood jams are an important and ubiquitous feature of many river channels with their number, placement and spatial configuration determining their influence on channel morphology and flow characteristics. Further, engineered log jams are increasingly being constructed to develop, restore or maintain habitat diversity for key indicator specie such as salmon. However, questions remain as to the inter relationships between the logjams, the channel morphology, the flow characteristics and the habitat diversity under low flow conditions. Four engineered and one natural logjam were analyzed over a 3km reach of the South Fork Nooksack River, North Cascades National Park, USA during the summer low flow period. Non-intrusive three-dimensional topographic surveys of the river bed morphology surrounding the logjams was collected using a shallow water multibeam system. This was combined with terrestrial laser scans of the structure of the log jams above the waterline. Co-located high resolution flow velocity data was collected using an Acoustic Doppler Current Profiler. Discussion concentrates on providing a quantitative understanding of the effect of logjams on reach scale morphodynamics under low flow conditions. Multivariate statistical analysis of flow and topographic data in combination with log jam morphology allow the influences of the logjam on habitat suitability for key indicator species to be quantified. Results will be framed in terms of the effectiveness of the different logjam configurations on generating and promoting habitat diversity such as to aid future design and implementation.

Interactions among forest age, valley and channel morphology, and log jams regulate animal production in mountain streams

NASA Astrophysics Data System (ADS)

Walters, D. M.; Venarsky, M. P.; Hall, R. O., Jr.; Herdrich, A.; Livers, B.; Winkelman, D.; Wohl, E.

2014-12-01

Forest age and local valley morphometry strongly influence the form and function of mountain streams in Colorado. Streams in valleys with old growth forest (>350 years) have extensive log jam complexes that create multi-thread channel reaches with extensive pool habitat and large depositional areas. Streams in younger unmanaged forests (e.g., 120 years old) and intensively managed forests have much fewer log jams and lower wood loads. These are single-thread streams dominated by riffles and with little depositional habitat. We hypothesized that log jam streams would retain more organic matter and have higher metabolism, leading to greater production of stream macroinvertebrates and trout. Log jam reaches should also have greater emergence of adult aquatic insects, and consequently have higher densities of riparian spiders taking advantage of these prey. Surficial organic matter was 3-fold higher in old-growth streams, and these streams had much higher ecosystem respiration. Insect production (g m2 y-1) was similar among forest types, but fish density was four times higher in old-growth streams with copious log jams. However, at the valley scale, insect production (g m-1 valley-1) and trout density (number m-1 valley-1) was 2-fold and 10-fold higher, respectively, in old growth streams. This finding is because multi-thread reaches created by log jams have much greater stream area and stream length per meter of valley than single-thread channels. The more limited response of macroinvertebrates may be related to fish predation. Trout in old growth streams had similar growth rates and higher fat content than fish in other streams in spite of occurring at higher densities and higher elevation/colder temperatures. This suggests that the positive fish effect observed in old growth streams is related to greater availability of invertebrate prey, which is consistent with our original hypothesis. Preliminary analyses suggest that spider densities do not respond strongly to differences in stream morphology, but rather to changes in elevation and associated air temperatures. These results demonstrate strong indirect effects of forest age and valley morphometry on organic matter storage and animal secondary production in streams that is mediated by direct effects associated with the presence or absence of logjams.

Isothermal amplification detection of nucleic acids by a double-nicked beacon.

PubMed

Shi, Chao; Zhou, Meiling; Pan, Mei; Zhong, Guilin; Ma, Cuiping

2016-03-01

Isothermal and rapid amplification detection of nucleic acids is an important technology in environmental monitoring, foodborne pathogen detection, and point-of-care clinical diagnostics. Here we have developed a novel method of isothermal signal amplification for single-stranded DNA (ssDNA) detection. The ssDNA target could be used as an initiator, coupled with a double-nicked molecular beacon, to originate amplification cycles, achieving cascade signal amplification. In addition, the method showed good specificity and strong anti-jamming capability. Overall, it is a one-pot and isothermal strand displacement amplification method without the requirement of a stepwise procedure, which greatly simplifies the experimental procedure and decreases the probability of contamination of samples. With its advantages, the method would be very useful to detect nucleic acids in point-of-care or field use. Copyright © 2015 Elsevier Inc. All rights reserved.

78 FR 19088 - Airworthiness Directives; REIMS AVIATION S.A. Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-29

... pushrod to fail. Failure of the elevator pushrod could cause the flight control to jam, which could result... the elevator pushrod to jam and could result in loss of control. We are issuing this AD to require... controls, possibly resulting in loss of control of the aeroplane. For the reasons described above, this AD...

Jelly Jam, the People Preserver. Teaching Guide. An Environmental Manual for Teachers and Parents. Revised Edition.

ERIC Educational Resources Information Center

Friedman, Judi

Designed for teachers of students in grades 2 through 4, this teaching guide for a self-teaching, interdisciplinary reading and activity program comprises a complete supplemental reading, science, and social studies approach to the problems of environmental pollution. Jelly Jam, a caring little animal, helps children understand how air, water, and…

Flow, turbulence, and drag associated with engineered log jams in a fixed-bed experimental channel

USDA-ARS?s Scientific Manuscript database

Engineered log jams (ELJs) have become attractive alternatives for river restoration and bank stabilization programs. Yet the effects of ELJs on turbulent flow and the fluid forces acting on the ELJs are not well known, and such information could inform design criteria. In this study, a fixed-bed ph...

Study of the Efficiency of the Polarization-Diversity Reception of a Very Low Frequency Signal Against the Background of Atmospheric Noise and Jamming in the Communication-Channel Model

NASA Astrophysics Data System (ADS)

Metelev, S. A.; Lvov, A. V.

2017-12-01

We propose a model of forming the signals and interference in the very low frequency wave range. Using this model, we determine the potentials of the space-polarization interference compensators in a communication channel with natural interference and jamming.

Jelly Jam, the People Preserver. An Environmental Self-Teaching Activity Book. Bermuda Edition.

ERIC Educational Resources Information Center

Friedman, Judi

Designed for students in grades 2 through 4, this self-teaching, interdisciplinary reading and activity program approaches the environmental conditions, the state of natural resources, and the problems of pollution in Bermuda. A caring little animal named Jelly Jam is used to help children understand how air, water, and land pollution affect their…

The role of JAM-A in inflammatory bowel disease: unrevealing the ties that bind.

PubMed

Vetrano, Stefania; Danese, Silvio

2009-05-01

Tight junctions (TJ) are junctional proteins whose function is to maintain an intact intestinal epithelial barrier and regulate the paracellular movement of water and solutes. Altered TJ structure and epithelial permeability are observed in inflammatory bowel disease and seem to have an important role in the pathogenesis of these diseases. Junctional adhesion molecule-A (JAM-A) is a protein expressed at tight junctions of epithelial and endothelial cells, as well as on circulating leukocytes. Its function at tight junctions appears to be crucial as an extracellular adhesive molecule in the direct regulation of intestinal barrier function. This review focuses on the role of JAM-A in controlling mucosal homeostasis by regulating the integrity and permeability of epithelial barrier function.

Soft modes in the perceptron model for jamming.

NASA Astrophysics Data System (ADS)

Franz, Silvio

I will show how a well known neural network model \\x9Dthe perceptro provides a simple solvable model of glassy behavior and jamming. The glassy minima of the energy function of this model can be studied in full analytic detail. This allows the identification of two kind of soft modes the first ones associated to the existence a marginal glass phase and a hierarchical structure of the energy landscape, the second ones associated to isostaticity and marginality of jamming. These results highlight the universality of the spectrum of normal modes in disordered systems, and open the way toward a detailed analytical understanding of the vibrational spectrum of low-temperature glasses. This work was supported by a Grant from the Simons Foundation (454941 to Silvio Franz).

3D pulsed chaos lidar system.

PubMed

Cheng, Chih-Hao; Chen, Chih-Ying; Chen, Jun-Da; Pan, Da-Kung; Ting, Kai-Ting; Lin, Fan-Yi

2018-04-30

We develop an unprecedented 3D pulsed chaos lidar system for potential intelligent machinery applications. Benefited from the random nature of the chaos, conventional CW chaos lidars already possess excellent anti-jamming and anti-interference capabilities and have no range ambiguity. In our system, we further employ self-homodyning and time gating to generate a pulsed homodyned chaos to boost the energy-utilization efficiency. Compared to the original chaos, we show that the pulsed homodyned chaos improves the detection SNR by more than 20 dB. With a sampling rate of just 1.25 GS/s that has a native sampling spacing of 12 cm, we successfully achieve millimeter-level accuracy and precision in ranging. Compared with two commercial lidars tested side-by-side, namely the pulsed Spectroscan and the random-modulation continuous-wave Lidar-lite, the pulsed chaos lidar that is in compliance with the class-1 eye-safe regulation shows significantly better precision and a much longer detection range up to 100 m. Moreover, by employing a 2-axis MEMS mirror for active laser scanning, we also demonstrate real-time 3D imaging with errors of less than 4 mm in depth.

Chaotic CDMA watermarking algorithm for digital image in FRFT domain

NASA Astrophysics Data System (ADS)

Liu, Weizhong; Yang, Wentao; Feng, Zhuoming; Zou, Xuecheng

2007-11-01

A digital image-watermarking algorithm based on fractional Fourier transform (FRFT) domain is presented by utilizing chaotic CDMA technique in this paper. As a popular and typical transmission technique, CDMA has many advantages such as privacy, anti-jamming and low power spectral density, which can provide robustness against image distortions and malicious attempts to remove or tamper with the watermark. A super-hybrid chaotic map, with good auto-correlation and cross-correlation characteristics, is adopted to produce many quasi-orthogonal codes (QOC) that can replace the periodic PN-code used in traditional CDAM system. The watermarking data is divided into a lot of segments that correspond to different chaotic QOC respectively and are modulated into the CDMA watermarking data embedded into low-frequency amplitude coefficients of FRFT domain of the cover image. During watermark detection, each chaotic QOC extracts its corresponding watermarking segment by calculating correlation coefficients between chaotic QOC and watermarked data of the detected image. The CDMA technique not only can enhance the robustness of watermark but also can compress the data of the modulated watermark. Experimental results show that the watermarking algorithm has good performances in three aspects: better imperceptibility, anti-attack robustness and security.

A Homozygous Mutation in the Tight-Junction Protein JAM3 Causes Hemorrhagic Destruction of the Brain, Subependymal Calcification, and Congenital Cataracts

PubMed Central

Mochida, Ganeshwaran H.; Ganesh, Vijay S.; Felie, Jillian M.; Gleason, Danielle; Hill, R. Sean; Clapham, Katie Rose; Rakiec, Daniel; Tan, Wen-Hann; Akawi, Nadia; Al-Saffar, Muna; Partlow, Jennifer N.; Tinschert, Sigrid; Barkovich, A. James; Ali, Bassam; Al-Gazali, Lihadh; Walsh, Christopher A.

2010-01-01

The tight junction, or zonula occludens, is a specialized cell-cell junction that regulates epithelial and endothelial permeability, and it is an essential component of the blood-brain barrier in the cerebrovascular endothelium. In addition to functioning as a diffusion barrier, tight junctions are also involved in signal transduction. In this study, we identified a homozygous mutation in the tight-junction protein gene JAM3 in a large consanguineous family from the United Arab Emirates. Some members of this family had a rare autosomal-recessive syndrome characterized by severe hemorrhagic destruction of the brain, subependymal calcification, and congenital cataracts. Their clinical presentation overlaps with some reported cases of pseudo-TORCH syndrome as well as with cases involving mutations in occludin, another component of the tight-junction complex. However, massive intracranial hemorrhage distinguishes these patients from others. Homozygosity mapping identified the disease locus in this family on chromosome 11q25 with a maximum multipoint LOD score of 6.15. Sequence analysis of genes in the candidate interval uncovered a mutation in the canonical splice-donor site of intron 5 of JAM3. RT-PCR analysis of a patient lymphoblast cell line confirmed abnormal splicing, leading to a frameshift mutation with early termination. JAM3 is known to be present in vascular endothelium, although its roles in cerebral vasculature have not been implicated. Our results suggest that JAM3 is essential for maintaining the integrity of the cerebrovascular endothelium as well as for normal lens development in humans. PMID:21109224

Carbon storage in mountainous headwater streams: The role of old-growth forest and logjams

NASA Astrophysics Data System (ADS)

Beckman, Natalie D.; Wohl, Ellen

2014-03-01

We measured wood piece characteristics and particulate organic matter (POM) in stored sediments in 30 channel-spanning logjams along headwater streams in the Colorado Front Range, USA. Logjams are on streams flowing through old-growth (>200 years), disturbed (<200 years, natural disturbance), or altered (<200 years, logged) subalpine conifer forest. We examined how channel-spanning logjams influence riverine carbon storage (measured as the total volatile carbon fraction of stored sediment and instream wood). Details of carbon storage associated with logjams reflect age and disturbance history of the adjacent riparian forest. A majority of the carbon within jams is stored as wood. Wood volume is significantly larger in old-growth and disturbed reaches than in altered reaches. Carbon storage also differs in relation to forest characteristics. Sediment from old-growth streams has significantly higher carbon content than altered streams. Volume of carbon stored in jam sediment correlates with jam wood volume in old-growth and disturbed forests, but not in altered forests. Forest stand age and wood volume within a jam explain 43% of the variation of carbon stored in jam sediment. First-order estimates of the amount of carbon stored within a stream reach show an order of magnitude difference between disturbed and altered reaches. Our first-order estimates of reach-scale riverine carbon storage suggest that the carbon per hectare stored in streams is on the same order of magnitude as the carbon stored as dead biomass in terrestrial subalpine forests of the region. Of particular importance, old-growth forest correlates with more carbon storage in rivers.

Large wood transport and jam formation in a series of flume experiments

NASA Astrophysics Data System (ADS)

Davidson, S. L.; MacKenzie, L. G.; Eaton, B. C.

2015-12-01

Large wood has historically been removed from streams, resulting in the depletion of in-stream wood in waterways worldwide. As wood increases morphological and hydraulic complexity, the addition of large wood is commonly employed as a means to rehabilitate in-stream habitat. At present, however, the scientific understanding of wood mobilization and transport is incomplete. This paper presents results from a series of four flume experiments in which wood was added to a reach to investigate the piece and reach characteristics that determine wood stability and transport, as well as the time scale required for newly recruited wood to self-organize into stable jams. Our results show that wood transitions from a randomly distributed newly recruited state to a self-organized, or jam-stabilized state, over the course of a single bankfull flow event. Statistical analyses of piece mobility during this transitional period indicate that piece irregularities, especially rootwads, dictate the stability of individual wood pieces; rootwad presence or absence accounts for up to 80% of the variance explained by linear regression models for transport distance. Furthermore, small pieces containing rootwads are especially stable. Large ramped pieces provide nuclei for the formation of persistent wood jams, and the frequency of these pieces in the reach impacts the travel distance of mobile wood. This research shows that the simulation of realistic wood dynamics is possible using a simplified physical model, and also has management implications, as it suggests that randomly added wood may organize into persistent, stable jams, and characterizes the time scale for this transition.

75 FR 28478 - Airworthiness Directives; Eurocopter France (ECF) Model AS332L1 and AS332L2 Helicopters

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-21

... fully tilted the seat shoulder harness could become jammed between the seat and bulkhead. This condition, if not corrected, could result in the shoulder harness binding and causing the inertial reel to... seat backrest is fully tilted, there is a risk of the shoulder harness jamming between the seat and...

Popular Culture, Cultural Resistance, and Anticonsumption Activism: An Exploration of Culture Jamming as Critical Adult Education

ERIC Educational Resources Information Center

Sandlin, Jennifer A.

2007-01-01

This chapter examines popular culture as a site of cultural resistance. Specifically, it explores how "culture jamming," a cultural-resistance activity, can be a form of adult education. It examines adult education and learning as it intersects with both consumerism and popular culture. Focus is placed on a growing social movement of individuals…

Flood plain and channel dynamics of the Quinault and Queets Rivers, Washington, USA

USGS Publications Warehouse

O'Connor, J. E.; Jones, M.A.; Haluska, T.L.

2003-01-01

Observations from this study and previous studies on the Queets River show that channel and flood-plain dynamics and morphology are affected by interactions between flow, sediment, and standing and entrained wood, some of which likely involve time frames similar to 200–500-year flood-plain half-lives. On the upper Quinault River and Queets River, log jams promote bar growth and consequent channel shifting, short-distance avulsions, and meander cutoffs, resulting in mobile and wide active channels. On the lower Quinault River, large portions of the channel are stable and flow within vegetated flood plains. However, locally, channel-spanning log jams have caused channel avulsions within reaches that have been subsequently mobile for several decades. In all three reaches, log jams appear to be areas of conifer germination and growth that may later further influence channel and flood-plain conditions on long time scales by forming flood-plain areas resistant to channel migration and by providing key members of future log jams. Appreciation of these processes and dynamics and associated temporal and spatial scales is necessary to formulate effective long-term approaches to managing fluvial ecosystems in forested environments.

The Packing and Jamming of Real Polymer Chains

NASA Astrophysics Data System (ADS)

Xue, Gi; Teng, Chao

2010-03-01

Jamming make a hope to unifying theme for granular materials, glasses and threshold behavior in materials. Here we experimentally prepared a real polymer (polystyrene, PS) with various packing density which was described by inter-segment distances (r) detected by NMR. We cold-pressed PS powder at 20 ^oC (with shearing) and then released the pressure. We found that a transparent pellet with high modulus was formed. PS is usually manufactured by a hot-melting process at 180 ^oC. The rigidity and transparency of our cold-pressed pellet and its accuracy of the form are testimony that the PS powder once flowed under cold compression to take the shape of its container. This shear-induced melting is exactly what is expected within the jamming picture. By measuring r and the applied pressure σ under which the polymer chain starts to flow, we drew a schematic jamming phase diagram. The σ-r curve for a real polymer is convex at r < 0.5 nm, while it becomes concave as r is larger than 1 nm. It is the van der Waals attraction that acts as a confining pressure on segments, and makes the σ-r curve convex on the very short scales.

Jamming Behavior of Domain Walls in an Antiferromagnetic Film

NASA Astrophysics Data System (ADS)

Sinha, Sunil

2014-03-01

Over the last few years, attempts have been made to unify many aspects of the freezing behavior of glasses, granular materials, gels, supercooled liquids, etc. into a general conceptual framework of what is called jamming behavior. This occurs when particles reach packing densities high enough that their motions become highly restricted. A general phase diagram has been proposed onto which various materials systems, e.g glasses or granular materials, can be mapped. We will discuss some recent applications of resonant and non-resonant soft X-ray Grazing Incidence Scattering to mesoscopic science, for example the study of magnetic domain wall fluctuations in thin films. For these studies, we use resonant magnetic x-ray scattering with a coherent photon beam and the technique of X-ray Photon Correlation Spectroscopy. find that at the ordering temperature the domains of an antiferromagnetic system, namely Dysprosium metal, behave very much also like a jammed system and their associated fluctuations exhibit behavior which exhibit some of the universal characteristics of jammed systems, such as non-exponential relaxation and Vogel-Fulcher type freezing. Work supported by Basic Energy Sciences, U.S. Dept. of Energy under Grant Number: DE-SC0003678.

Sculpting Pickering Emulsion Droplets by Arrest and Jamming

NASA Astrophysics Data System (ADS)

Burke, Christopher; Wei, Zengyi; Caggioni, Marco; Spicer, Patrick; Atherton, Tim

Pickering emulsion droplets can be arrested into non-spherical shapes--useful for applications such as active delivery--through a general mechanism of deformation followed by absorption of additional colloidal particles onto the interface, relaxation of the droplet caused by surface tension and arrest at some point due to crowding of the particles. We perform simulations of the arrest process to clarify the relative importance of diffusive rearrangement of particles and collective forcing due to surface evolution. Experiment and theory are compared, giving insight into the stability of the resulting capsules and the robustness of the production process for higher-throughput production in, for example, microfluidic systems. We adapt theoretical tools from the jamming literature to better understand the arrested configurations and long timescale evolution of the system: using linear programming and a penalty function approach, we identify unjamming motions in kinetically arrested states. We propose a paradigm of ``metric jamming'' to describe the limiting behavior of this class of system: a structure is metric-jammed if it is stable with respect to collective motion of the particles as well as evolution of the hypersurface on which the packing is embedded. Supported by a Cottrell Award from the Research Corporation for Science Advancement.

Cargo crowding at actin-rich regions along axons causes local traffic jams.

PubMed

Sood, Parul; Murthy, Kausalya; Kumar, Vinod; Nonet, Michael L; Menon, Gautam I; Koushika, Sandhya P

2018-03-01

Steady axonal cargo flow is central to the functioning of healthy neurons. However, a substantial fraction of cargo in axons remains stationary up to several minutes. We examine the transport of precursors of synaptic vesicles (pre-SVs), endosomes and mitochondria in Caenorhabditis elegans touch receptor neurons, showing that stationary cargo are predominantly present at actin-rich regions along the neuronal process. Stationary vesicles at actin-rich regions increase the propensity of moving vesicles to stall at the same location, resulting in traffic jams arising from physical crowding. Such local traffic jams at actin-rich regions are likely to be a general feature of axonal transport since they also occur in Drosophila neurons. Repeated touch stimulation of C. elegans reduces the density of stationary pre-SVs, indicating that these traffic jams can act as both sources and sinks of vesicles. This suggests that vesicles trapped in actin-rich regions are functional reservoirs that may contribute to maintaining robust cargo flow in the neuron. A video abstract of this article can be found at: Video S1; Video S2. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Influence of anisotropy on percolation and jamming of linear k-mers on square lattice with defects

NASA Astrophysics Data System (ADS)

Tarasevich, Yu Yu; Laptev, V. V.; Burmistrov, A. S.; Shinyaeva, T. S.

2015-09-01

By means of the Monte Carlo simulation, we study the layers produced by the random sequential adsorption of the linear rigid objects (k-mers also known as rigid or stiff rods, sticks, needles) onto the square lattice with defects in the presence of an external field. The value of k varies from 2 to 32. The point defects randomly and uniformly placed on the substrate hinder adsorption of the elongated objects. The external field affects isotropic deposition of the particles, consequently the deposited layers are anisotropic. We study the influence of the defect concentration, the length of the objects, and the external field on the percolation threshold and the jamming concentration. Our main findings are (i) the critical defect concentration at which the percolation never occurs even at jammed state decreases for short k-mers (k < 16) and increases for long k-mers (k > 16) as anisotropy increases, (ii) the corresponding critical k-mer concentration decreases with anisotropy growth, (iii) the jamming concentration decreases drastically with growth of k-mer length for any anisotropy, (iv) for short k-mers, the percolation threshold is almost insensitive to the defect concentration for any anisotropy.

Shear thickening and jamming in suspensions of different particle shapes

NASA Astrophysics Data System (ADS)

Brown, Eric; Zhang, Hanjun; Forman, Nicole; Betts, Douglas; Desimone, Joseph; Maynor, Benjamin; Jaeger, Heinrich

2012-02-01

We investigated the role of particle shape on shear thickening and jamming in densely packed suspensions. Various particle shapes were fabricated including rods of different aspect ratios and non-convex hooked rods. A rheometer was used to measure shear stress vs. shear rate for a wide range of packing fractions for each shape. Each suspensions exhibits qualitatively similar Discontinuous Shear Thickening, in which the logarithmic slope of the stress vs. shear rate has the same scaling for each convex shape and diverges at a critical packing fraction φc. The value of φc varies with particle shape, and coincides with the onset of a yield stress, a.k.a. the jamming transition. This suggests the jamming transition controls shear thickening, and the only effect of particle shape on steady state bulk rheology of convex particles is a shift of φc. Intriguingly, viscosity curves for non-convex particles do not collapse on the same set as convex particles, showing strong shear thickening over a wider range of packing fraction. Qualitative shape dependence was only found in steady state rheology when the system was confined to small gaps where large aspect ratio particle are forced to order.

Tabletop Traffic Jams: Modeling Traffic Jams using Self Propelled Particles

NASA Astrophysics Data System (ADS)

Yadav, Vikrant; Kudrolli, Arshad

2015-03-01

We model behavior of traffic using Self Propelled Particles (SPPs). Granular rods with asymmetric mass distribution confined to move in a circular channel on a vibrated substrate and interact with each other through inelastic collision serve as our model vehicle. Motion of a single vehicle is observed to be composed of 2 parts, a linear velocity in the direction of lighter end of particle and a non-Gaussian random velocity. We find that the collective mean speed of the SPPs is constant over a wide range of line densities before decreasing rapidly as the maximum packing is approached indicating the spontaneous formation of Phantom jams. This decrease in speed is observed to be far greater than any small differences in the mean drift speed of individual SPPs , and occurs as the collision frequency between SPPs increase exponentially with line density. However the random velocity component of SPPs remain super-diffusive over entire range of line densities. While the collective motion at low densities is characterized by caravan following behind the slowest particle leading to clustering, at higher densities we see formation of jamming waves travelling in direction opposite to that of motion of particles.

Structure of jammed configurations and their relation to unjamming times

NASA Astrophysics Data System (ADS)

Birwa, Sumit Kumar; Merrigan, Carl; Chakraborty, Bulbul; Tewari, Shubha

The distribution of the times for the cessation of flow of grains falling under gravity in a vertical hopper is known to be exponential. Recent experiments have shown, however, that the time lapse between avalanches follows a power-law distribution when the hopper is unjammed using periodic vertical vibrations. The reasons for this distribution of the unjamming times, which indicates the time needed for an applied continuous perturbation to induce another avalanche, are not well understood. We report on a numerical simulation of granular hopper flow using LAMMPS in which we seek to understand the origin and scope of this behavior. We find that cessation of flow is related to the formation of a stable arch that spans the system. However, the actual structure of the jammed configuration varies and is closely related to the unjamming time. We find that the symmetry of the arches is an important parameter in determining the strength of the jammed configurations. Using different force thresholds, we have characterized the contact networks around the arches which provides stability to the packed structure and analyzed the strength of various jammed configurations. Supported by NSF Grant DMR1409093 and DGE1068620.

Jamming and condensation in one-dimensional driven flow

NASA Astrophysics Data System (ADS)

Soh, Hyungjoon; Ha, Meesoon; Jeong, Hawoong

2018-03-01

We revisit the slow-bond (SB) problem of the one-dimensional (1D) totally asymmetric simple exclusion process (TASEP) with modified hopping rates. In the original SB problem, it turns out that a local defect is always relevant to the system as jamming, so that phase separation occurs in the 1D TASEP. However, crossover scaling behaviors are also observed as finite-size effects. In order to check if the SB can be irrelevant to the system with particle interaction, we employ the condensation concept in the zero-range process. The hopping rate in the modified TASEP depends on the interaction parameter and the distance up to the nearest particle in the moving direction, besides the SB factor. In particular, we focus on the interplay of jamming and condensation in the current-density relation of 1D driven flow. Based on mean-field calculations, we present the fundamental diagram and the phase diagram of the modified SB problem, which are numerically checked. Finally, we discuss how the condensation of holes suppresses the jamming of particles and vice versa, where the partially condensed phase is the most interesting, compared to that in the original SB problem.

Jamming and condensation in one-dimensional driven flow.

PubMed

Soh, Hyungjoon; Ha, Meesoon; Jeong, Hawoong

2018-03-01

We revisit the slow-bond (SB) problem of the one-dimensional (1D) totally asymmetric simple exclusion process (TASEP) with modified hopping rates. In the original SB problem, it turns out that a local defect is always relevant to the system as jamming, so that phase separation occurs in the 1D TASEP. However, crossover scaling behaviors are also observed as finite-size effects. In order to check if the SB can be irrelevant to the system with particle interaction, we employ the condensation concept in the zero-range process. The hopping rate in the modified TASEP depends on the interaction parameter and the distance up to the nearest particle in the moving direction, besides the SB factor. In particular, we focus on the interplay of jamming and condensation in the current-density relation of 1D driven flow. Based on mean-field calculations, we present the fundamental diagram and the phase diagram of the modified SB problem, which are numerically checked. Finally, we discuss how the condensation of holes suppresses the jamming of particles and vice versa, where the partially condensed phase is the most interesting, compared to that in the original SB problem.

Intelligent Sensing and Classification in DSR-Based Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Dempsey, Tae; Sahin, Gokhan; Morton, Yu T. (Jade

Wireless ad hoc networks have fundamentally altered today's battlefield, with applications ranging from unmanned air vehicles to randomly deployed sensor networks. Security and vulnerabilities in wireless ad hoc networks have been considered at different layers, and many attack strategies have been proposed, including denial of service (DoS) through the intelligent jamming of the most critical packet types of flows in a network. This paper investigates the effectiveness of intelligent jamming in wireless ad hoc networks using the Dynamic Source Routing (DSR) and TCP protocols and introduces an intelligent classifier to facilitate the jamming of such networks. Assuming encrypted packet headers and contents, our classifier is based solely on the observable characteristics of size, inter-arrival timing, and direction and classifies packets with up to 99.4% accuracy in our experiments.

Passive and Active Analysis in DSR-Based Ad Hoc Networks

NASA Astrophysics Data System (ADS)

Dempsey, Tae; Sahin, Gokhan; Morton, Y. T. (Jade)

Security and vulnerabilities in wireless ad hoc networks have been considered at different layers, and many attack strategies have been proposed, including denial of service (DoS) through the intelligent jamming of the most critical packet types of flows in a network. This paper investigates the effectiveness of intelligent jamming in wireless ad hoc networks using the Dynamic Source Routing (DSR) and TCP protocols and introduces an intelligent classifier to facilitate the jamming of such networks. Assuming encrypted packet headers and contents, our classifier is based solely on the observable characteristics of size, inter-arrival timing, and direction and classifies packets with up to 99.4% accuracy in our experiments. Furthermore, we investigate active analysis, which is the combination of a classifier and intelligent jammer to invoke specific responses from a victim network.

Finite size scaling analysis on Nagel-Schreckenberg model for traffic flow

NASA Astrophysics Data System (ADS)

Balouchi, Ashkan; Browne, Dana

2015-03-01

The traffic flow problem as a many-particle non-equilibrium system has caught the interest of physicists for decades. Understanding the traffic flow properties and though obtaining the ability to control the transition from the free-flow phase to the jammed phase plays a critical role in the future world of urging self-driven cars technology. We have studied phase transitions in one-lane traffic flow through the mean velocity, distributions of car spacing, dynamic susceptibility and jam persistence -as candidates for an order parameter- using the Nagel-Schreckenberg model to simulate traffic flow. The length dependent transition has been observed for a range of maximum velocities greater than a certain value. Finite size scaling analysis indicates power-law scaling of these quantities at the onset of the jammed phase.

Research on metal-plated cellulose nitrate flakes and their infrared / millimeter wave characteristics

NASA Astrophysics Data System (ADS)

Ye, Shu-qin; Zhu, Chen-guang; Wang, Li-hong; Ou'yang, De-hua; Pan, Gong-pei

2016-10-01

Copper-plated and silver-plated cellulose nitrate flakes, which were prepared by using chemical plating technology, were used to jam infrared detector and millimeter-wave radar. It was tested for the conductivity and infrared jamming performance of plating and also the RCS (Radar Cross Section) performance of millimeter-wave radar. Test results showed that the prepared metal-plated cellulose nitrate flakes have obvious conductivity, and infrared total radiation energy of silver plating and copper plating had approximately increased 32% and 21% respectively. Through determination, the millimeter-wave reflecting property and RCS of silver-plated cellulose nitrate flakes were higher than that of copper-plated cellulose nitrate flakes. Therefore, silver-plated cellulose nitrate flakes can be used as an effective infrared / millimeter wave composite jamming material.

Worst case encoder-decoder policies for a communication system in the presence of an unknown probabilistic jammer

NASA Astrophysics Data System (ADS)

Cascio, David M.

1988-05-01

States of nature or observed data are often stochastically modelled as Gaussian random variables. At times it is desirable to transmit this information from a source to a destination with minimal distortion. Complicating this objective is the possible presence of an adversary attempting to disrupt this communication. In this report, solutions are provided to a class of minimax and maximin decision problems, which involve the transmission of a Gaussian random variable over a communications channel corrupted by both additive Gaussian noise and probabilistic jamming noise. The jamming noise is termed probabilistic in the sense that with nonzero probability 1-P, the jamming noise is prevented from corrupting the channel. We shall seek to obtain optimal linear encoder-decoder policies which minimize given quadratic distortion measures.

Influence of landscape geomorphology on large wood jams and salmonids in an old-growth river of Upper Michigan

Treesearch

Arthur E. L. Morris; P. Charles Goebel; Lance R. Williams; Brian J. Palik

2006-01-01

We investigated the structure of large wood jams (LWJ) and their use by brook trout (Salvelinus fontinalis Mitchill) and other fish in four geomorphically-distinct sections of the Little Carp River, a small river flowing through an uncut, old-growth, northern hardwood-conifer forest along the south shore of Lake Superior, Upper Michigan. We...

Magic at the Marketplace: Choice Blindness for the Taste of Jam and the Smell of Tea

ERIC Educational Resources Information Center

Hall, Lars; Johansson, Petter; Tarning, Betty; Sikstrom, Sverker; Deutgen, Therese

2010-01-01

We set up a tasting venue at a local supermarket and invited passerby shoppers to sample two different varieties of jam and tea, and to decide which alternative in each pair they preferred the most. Immediately after the participants had made their choice, we asked them to again sample the chosen alternative, and to verbally explain why they chose…

Broadband and High power Reactive Jamming Resilient Wireless Communication

DTIC Science & Technology

2017-10-21

Broadband and High -power Reactive Jamming Resilient Wireless Communication The views, opinions and/or findings contained in this report are those of... available in extremely hostile environments, where FHSS and DSSS are completely defeated by a broadband and high -power reactive jammer. b. Wireless...SECURITY CLASSIFICATION OF: 1. REPORT DATE (DD-MM-YYYY) 4. TITLE AND SUBTITLE 13. SUPPLEMENTARY NOTES 12. DISTRIBUTION AVAILIBILITY STATEMENT 6. AUTHORS

Complete genome sequence of the xylan-degrading subseafloor bacterium Microcella alkaliphila JAM-AC0309.

PubMed

Kurata, Atsushi; Hirose, Yuu; Misawa, Naomi; Wakazuki, Sachiko; Kishimoto, Noriaki; Kobayashi, Tohru

2016-03-10

Here we report the complete genome sequence of Microcella alkaliphila JAM-AC0309, which was newly isolated from the deep subseafloor core sediment from offshore of the Shimokita Peninsula of Japan. An array of genes related to utilization of xylan in this bacterium was identified by whole genome analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Worst-Case Cooperative Jamming for Secure Communications in CIoT Networks.

PubMed

Li, Zhen; Jing, Tao; Ma, Liran; Huo, Yan; Qian, Jin

2016-03-07

The Internet of Things (IoT) is a significant branch of the ongoing advances in the Internet and mobile communications. The use of a large number of IoT devices makes the spectrum scarcity problem even more serious. The usable spectrum resources are almost entirely occupied, and thus, the increasing radio access demands of IoT devices cannot be met. To tackle this problem, the Cognitive Internet of Things (CIoT) has been proposed. In a CIoT network, secondary users, i.e., sensors and actuators, can access the licensed spectrum bands provided by licensed primary users (such as telephones). Security is a major concern in CIoT networks. However, the traditional encryption method at upper layers (such as symmetric cryptography and asymmetric cryptography) may be compromised in CIoT networks, since these types of networks are heterogeneous. In this paper, we address the security issue in spectrum-leasing-based CIoT networks using physical layer methods. Considering that the CIoT networks are cooperative networks, we propose to employ cooperative jamming to achieve secrecy transmission. In the cooperative jamming scheme, a certain secondary user is employed as the helper to harvest energy transmitted by the source and then uses the harvested energy to generate an artificial noise that jams the eavesdropper without interfering with the legitimate receivers. The goal is to minimize the signal to interference plus noise ratio (SINR) at the eavesdropper subject to the quality of service (QoS) constraints of the primary traffic and the secondary traffic. We formulate the considered minimization problem into a two-stage robust optimization problem based on the worst-case Channel State Information of the Eavesdropper. By using semi-definite programming (SDP), the optimal solutions of the transmit covariance matrices can be obtained. Moreover, in order to build an incentive mechanism for the secondary users, we propose an auction framework based on the cooperative jamming scheme. The proposed auction framework jointly formulates the helper selection and the corresponding energy allocation problems under the constraint of the eavesdropper's SINR. By adopting the Vickrey auction, truthfulness and individual rationality can be guaranteed. Simulation results demonstrate the good performance of the cooperative jamming scheme and the auction framework.

Modeling wood dynamics, jam formation, and sediment storage in a gravel-bed stream

NASA Astrophysics Data System (ADS)

Eaton, B. C.; Hassan, M. A.; Davidson, S. L.

2012-12-01

In small and intermediate sized streams, the interaction between wood and bed material transport often determines the nature of the physical habitat, which in turn influences the health of the stream's ecosystem. We present a stochastic model that can be used to simulate the effects on physical habitat of forest fires, climate change, and other environmental disturbances that alter wood recruitment. The model predicts large wood (LW) loads in a stream as well as the volume of sediment stored by the wood; while it is parameterized to describe gravel bed streams similar to a well-studied field prototype, Fishtrap Creek, British Columbia, it can be calibrated to other systems as well. In the model, LW pieces are produced and modified over time as a result of random tree-fall, LW breakage, LW movement, and piece interaction to form LW jams. Each LW piece traps a portion of the annual bed material transport entering the reach and releases the stored sediment when the LW piece is entrained and moved. The equations governing sediment storage are based on a set of flume experiments also scaled to the field prototype. The model predicts wood loads ranging from 70 m3/ha to more than 300 m3/ha, with a mean value of 178 m3/ha: both the range and the mean value are consistent with field data from streams with similar riparian forest types and climate. The model also predicts an LW jam spacing that is consistent with field data. Furthermore, our modeling results demonstrate that the high spatial and temporal variability in sediment storage, sediment transport, and channel morphology associated with LW-dominated streams occurs only when LW pieces interact and form jams. Model runs that do not include jam formation are much less variable. These results suggest that river restoration efforts using engineered LW pieces that are fixed in place and not permitted to interact will be less successful at restoring the geomorphic processes responsible for producing diverse, productive physical habitats than efforts using LW pieces that are free to move, interact, and form LW jams.

The role of particle jamming on the formation and stability of step-pool morphology: insight from a reduced-complexity model

NASA Astrophysics Data System (ADS)

Saletti, M.; Molnar, P.; Hassan, M. A.

2017-12-01

Granular processes have been recognized as key drivers in earth surface dynamics, especially in steep landscapes because of the large size of sediment found in channels. In this work we focus on step-pool morphologies, studying the effect of particle jamming on step formation. Starting from the jammed-state hypothesis, we assume that grains generate steps because of particle jamming and those steps are inherently more stable because of additional force chains in the transversal direction. We test this hypothesis with a particle-based reduced-complexity model, CAST2, where sediment is organized in patches and entrainment, transport and deposition of grains depend on flow stage and local topography through simplified phenomenological rules. The model operates with 2 grain sizes: fine grains, that can be mobilized both my large and moderate flows, and coarse grains, mobile only during large floods. First, we identify the minimum set of processes necessary to generate and maintain steps in a numerical channel: (a) occurrence of floods, (b) particle jamming, (c) low sediment supply, and (d) presence of sediment with different entrainment probabilities. Numerical results are compared with field observations collected in different step-pool channels in terms of step density, a variable that captures the proportion of the channel occupied by steps. Not only the longitudinal profiles of numerical channels display step sequences similar to those observed in real step-pool streams, but also the values of step density are very similar when all the processes mentioned before are considered. Moreover, with CAST2 it is possible to run long simulations with repeated flood events, to test the effect of flood frequency on step formation. Numerical results indicate that larger step densities belong to system more frequently perturbed by floods, compared to system having a lower flood frequency. Our results highlight the important interactions between external hydrological forcing and internal geomorphic adjustment (e.g. jamming) on the response of step-pool streams, showing the potential of reduced-complexity models in fluvial geomorphology.

Nonlocal rheological properties of granular flows near a jamming limit.

PubMed

Aranson, Igor S; Tsimring, Lev S; Malloggi, Florent; Clément, Eric

2008-09-01

We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology. The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.

Higher-order corrections to the effective potential close to the jamming transition in the perceptron model

NASA Astrophysics Data System (ADS)

Altieri, Ada

2018-01-01

In view of the results achieved in a previously related work [A. Altieri, S. Franz, and G. Parisi, J. Stat. Mech. (2016) 093301], 10.1088/1742-5468/2016/09/093301, regarding a Plefka-like expansion of the free energy up to the second order in the perceptron model, we improve the computation here focusing on the role of third-order corrections. The perceptron model is a simple example of constraint satisfaction problem, falling in the same universality class as hard spheres near jamming and hence allowing us to get exact results in high dimensions for more complex settings. Our method enables to define an effective potential (or Thouless-Anderson-Palmer free energy), namely a coarse-grained functional, which depends on the generalized forces and the effective gaps between particles. The analysis of the third-order corrections to the effective potential reveals that, albeit irrelevant in a mean-field framework in the thermodynamic limit, they might instead play a fundamental role in considering finite-size effects. We also study the typical behavior of generalized forces and we show that two kinds of corrections can occur. The first contribution arises since the system is analyzed at a finite distance from jamming, while the second one is due to finite-size corrections. We nevertheless show that third-order corrections in the perturbative expansion vanish in the jamming limit both for the potential and the generalized forces, in agreement with the isostaticity argument proposed by Wyart and coworkers. Finally, we analyze the relevant scaling solutions emerging close to the jamming line, which define a crossover regime connecting the control parameters of the model to an effective temperature.

Higher-order corrections to the effective potential close to the jamming transition in the perceptron model.

PubMed

Altieri, Ada

2018-01-01

In view of the results achieved in a previously related work [A. Altieri, S. Franz, and G. Parisi, J. Stat. Mech. (2016) 093301]10.1088/1742-5468/2016/09/093301, regarding a Plefka-like expansion of the free energy up to the second order in the perceptron model, we improve the computation here focusing on the role of third-order corrections. The perceptron model is a simple example of constraint satisfaction problem, falling in the same universality class as hard spheres near jamming and hence allowing us to get exact results in high dimensions for more complex settings. Our method enables to define an effective potential (or Thouless-Anderson-Palmer free energy), namely a coarse-grained functional, which depends on the generalized forces and the effective gaps between particles. The analysis of the third-order corrections to the effective potential reveals that, albeit irrelevant in a mean-field framework in the thermodynamic limit, they might instead play a fundamental role in considering finite-size effects. We also study the typical behavior of generalized forces and we show that two kinds of corrections can occur. The first contribution arises since the system is analyzed at a finite distance from jamming, while the second one is due to finite-size corrections. We nevertheless show that third-order corrections in the perturbative expansion vanish in the jamming limit both for the potential and the generalized forces, in agreement with the isostaticity argument proposed by Wyart and coworkers. Finally, we analyze the relevant scaling solutions emerging close to the jamming line, which define a crossover regime connecting the control parameters of the model to an effective temperature.

Fragility and hysteretic creep in frictional granular jamming.

PubMed

Bandi, M M; Rivera, M K; Krzakala, F; Ecke, R E

2013-04-01

The granular jamming transition is experimentally investigated in a two-dimensional system of frictional, bidispersed disks subject to quasistatic, uniaxial compression without vibrational disturbances (zero granular temperature). Three primary results are presented in this experimental study. First, using disks with different static friction coefficients (μ), we experimentally verify numerical results that predict jamming onset at progressively lower packing fractions with increasing friction. Second, we show that the first compression cycle measurably differs from subsequent cycles. The first cycle is fragile-a metastable configuration with simultaneous jammed and unjammed clusters-over a small packing fraction interval (φ(1)<φ<φ(2)) and exhibits simultaneous exponential rise in pressure and exponential decrease in disk displacements over the same packing fraction interval. This fragile behavior is explained through a percolation mechanism of stressed contacts where cluster growth exhibits spatial correlation with disk displacements and contributes to recent results emphasizing fragility in frictional jamming. Control experiments show that the fragile state results from the experimental incompatibility between the requirements for zero friction and zero granular temperature. Measurements with several disk materials of varying elastic moduli E and friction coefficients μ show that friction directly controls the start of the fragile state but indirectly controls the exponential pressure rise. Finally, under repetitive loading (compression) and unloading (decompression), we find the system exhibits pressure hysteresis, and the critical packing fraction φ(c) increases slowly with repetition number. This friction-induced hysteretic creep is interpreted as the granular pack's evolution from a metastable to an eventual structurally stable configuration. It is shown to depend on the quasistatic step size Δφ, which provides the only perturbative mechanism in the experimental protocol, and the friction coefficient μ, which acts to stabilize the pack.

[The diagnostic value of dual-energy CT and 3 Tesla MRI in the diagnosis of German Mardi Gras donuts--where is the mustard, where is the custard and where is the jam?].

PubMed

Morhard, D; Dietrich, O; Reiser, M; Ertl-Wagner, B

2008-04-01

As a Mardi Gras joke, the original jam or custard fillings of German Mardi Gras donuts are frequently replaced with mustard which cannot be identified on the outside of the donut. The aim of our study was to evaluate the impact of modern CT and MRI techniques on the diagnostic evaluation of donuts filled with mustard, jam or custard. 4 commercially available donuts were included in the study. One was filled with custard (PK) and one with jam (MK). Two donuts were specifically prepared and filled with Bavarian mustard (SK1) or extra-hot (SK2) mustard. 3 Tesla MRI was performed with T 2- and T 1-weighted STIR, diffusion and susceptibility-weighted (SWI) sequences. In addition, the donuts underwent dual-energy CT. PK was able to be easily differentiated from the other donuts due to its hyperintensity in the STIR sequences and hypointensity in the T 1-weighted sequences. MK was able to be differentiated from S 1K and S 2K on the basis of its diffusion properties. S 1K demonstrated a pronounced heterogeneity of its matrix, especially in SWI. In CT, PK showed a pronounced hypoattenuation with negative Hounsfield units in contrast to the strongly hyperdense MK, S 1K and S 2K. S 1K and S 2K demonstrated X-ray attenuation considerably dependent on the X-ray energy. Donuts filled with jam, custard or mustard can be readily differentiated by modern MRI and CT techniques. Therefore, eating a mustard-filled donut can be reliably avoided.

Non-local rheological properties of granular flows near a jamming limit.

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

Aranson, I. S.; Tsimring, L. S.; Malloggi, F.

2008-01-01

We study the rheology of sheared granular flows close to a jamming transition. We use the approach of partially fluidized theory (PFT) with a full set of equations extending the thin layer approximation derived previously for the description of the granular avalanches phenomenology. This theory provides a picture compatible with a local rheology at large shear rates [G. D. R. Midi, Eur. Phys. J. E 14, 341 (2004)] and it works in the vicinity of the jamming transition, where a description in terms of a simple local rheology comes short. We investigate two situations displaying important deviations from local rheology.more » The first one is based on a set of numerical simulations of sheared soft two-dimensional circular grains. The next case describes previous experimental results obtained on avalanches of sandy material flowing down an incline. Both cases display, close to jamming, significant deviations from the now standard Pouliquen's flow rule [O. Pouliquen, Phys. Fluids 11, 542 (1999); 11, 1956 (1999)]. This discrepancy is the hallmark of a strongly nonlocal rheology and in both cases, we relate the empirical results and the outcomes of PFT. The numerical simulations show a characteristic constitutive structure for the fluid part of the stress involving the confining pressure and the material stiffness that appear in the form of an additional dimensionless parameter. This constitutive relation is then used to describe the case of sandy flows. We show a quantitative agreement as far as the effective flow rules are concerned. A fundamental feature is identified in PFT as the existence of a jammed layer developing in the vicinity of the flow arrest that corroborates the experimental findings. Finally, we study the case of solitary erosive granular avalanches and relate the outcome with the PFT analysis.« less

Packaged silica microsphere-taper coupling system for robust thermal sensing application.

PubMed

Yan, Ying-Zhan; Zou, Chang-Ling; Yan, Shu-Bin; Sun, Fang-Wen; Ji, Zhe; Liu, Jun; Zhang, Yu-Guang; Wang, Li; Xue, Chen-Yang; Zhang, Wen-Dong; Han, Zheng-Fu; Xiong, Ji-Jun

2011-03-28

We propose and realize a novel packaged microsphere-taper coupling structure (PMTCS) with a high quality factor (Q) up to 5×10(6) by using the low refractive index (RI) ultraviolet (UV) glue as the coating material. The optical loss of the PMTCS is analyzed experimentally and theoretically, which indicate that the Q is limited by the glue absorption and the radiation loss. Moreover, to verify the practicability of the PMTCS, thermal sensing experiments are carried out, showing the excellent convenience and anti-jamming ability of the PMTCS with a high temperature resolution of 1.1×10(-3) ◦C. The experiments also demonstrate that the PMTCS holds predominant advantages, such as the robustness, mobility, isolation, and the PMTCS can maintain the high Q for a long time. The above advantages make the PMTCS strikingly attractive and potential in the fiber-integrated sensors and laser.

Multifunctional nanocomposite hollow fiber membranes by solvent transfer induced phase separation.

PubMed

Haase, Martin F; Jeon, Harim; Hough, Noah; Kim, Jong Hak; Stebe, Kathleen J; Lee, Daeyeon

2017-11-01

The decoration of porous membranes with a dense layer of nanoparticles imparts useful functionality and can enhance membrane separation and anti-fouling properties. However, manufacturing of nanoparticle-coated membranes requires multiple steps and tedious processing. Here, we introduce a facile single-step method in which bicontinuous interfacially jammed emulsions are used to form nanoparticle-functionalized hollow fiber membranes. The resulting nanocomposite membranes prepared via solvent transfer-induced phase separation and photopolymerization have exceptionally high nanoparticle loadings (up to 50 wt% silica nanoparticles) and feature densely packed nanoparticles uniformly distributed over the entire membrane surfaces. These structurally well-defined, asymmetric membranes facilitate control over membrane flux and selectivity, enable the formation of stimuli responsive hydrogel nanocomposite membranes, and can be easily modified to introduce antifouling features. This approach forms a foundation for the formation of advanced nanocomposite membranes comprising diverse building blocks with potential applications in water treatment, industrial separations and as catalytic membrane reactors.

Investigation on navigation patterns of inertial/celestial integrated systems

NASA Astrophysics Data System (ADS)

Luo, Dacheng; Liu, Yan; Liu, Zhiguo; Jiao, Wei; Wang, Qiuyan

2014-11-01

It is known that Strapdown Inertial Navigation System (SINS), Global Navigation Satellite System (GNSS) and Celestial Navigation System (CNS) can complement each other's advantages. The SINS/CNS integrated system, which has the characteristics of strong autonomy, high accuracy and good anti-jamming, is widely used in military and civilian applications. Similar to SINS/GNSS integrated system, the SINS/CNS integrated system can also be divided into three kinds according to the difference of integrating depth, i.e., loosely coupled pattern, tightly coupled pattern and deeply coupled pattern. In this paper, the principle and characteristics of each pattern of SINS/CNS system are analyzed. Based on the comparison of these patterns, a novel deeply coupled SINS/CNS integrated navigation scheme is proposed. The innovation of this scheme is that a new star pattern matching method aided by SINS information is put forward. Thus the complementary features of these two subsystems are reflected.

Echo power analysis and simulation of low altitude radio fuze

NASA Astrophysics Data System (ADS)

Chen, Xiaolu; Chen, Biao; Xu, Tao; Xu, Suqin

2013-01-01

The echo power from the earth gound which was received by fuze plays an important role in aerial defense missile, especially when the fuze is working in the look down mode. It is necessary to analyze and even simulate the echo power signals to enhance the missile's anti-jamming ability. In this paper, the quantity of echo power from the earth ground of low altitude radio fuze was analyzed in detail. Three boundary equations of area irradiated by electromagnetic beams were presented, which include two equidistant curve equations and one equal-Doppler curve equation. The relationship between the working mode and the critical height was analyzed. The calculating formula of echo power waveform was derived. And based on the derived formula, the correlation between the maximal echo power and the incident height was given and simulated, which would be helpful for the further researches of low altitude radio fuze.

[An experimental study of the computer-controlled equipment for delivering volatile anesthetic agent].

PubMed

Sun, B; Li, W Z; Yue, Y; Jiang, C W; Xiao, L Y

2001-11-01

Our newly-designed computer-controlled equipment for delivering volatile anesthetic agent uses the subminiature singlechip processor as the central controlling unit. The variables, such as anesthesia method, anesthetic agent, the volume of respiratory loop, age of patient, sex, height, weight, environment temperature and the grade of ASA are all input from the keyboard. The anesthetic dosage, calculated by the singlechip processor, is converted into the signals controlling the pump to accurately deliver anesthetic agent into respiratory loop. We have designed an electrocircuit for the equipment to detect the status of the pump's operation, so we can assure of the safety and the stability of the equipment. The output precision of the equipment, with a good anti-jamming capability, is 1-2% for high flow anesthesia and 1-5% for closed-circuit anesthesia and its self-detecting working is reliable.

Precise Ionosphere Monitoring via a DSFH Satellite TT&C Link

NASA Astrophysics Data System (ADS)

Chen, Xiao; Li, Guangxia; Li, Zhiqiang; Yue, Chao

2014-11-01

A phase-coherent and frequency-hopped PN ranging system was developed, originally for the purpose of anti-jamming TT&C (tracking, telemetry and telecommand) of military satellites of China, including the Beidou-2 navigation satellites. The key innovation in the synchronization of this system is the unambiguous phase recovery of direct sequence and frequency hopping (DSFH) spread spectrum signal and the correction of frequency-dependent phase rotation caused by ionosphere. With synchronization achieved, a TEC monitoring algorithm based on maximum likelihood (ML) principle is proposed and its measuring precision is analyzed through ground simulation, onboard confirmation tests will be performed when transionosphere DSFH links are established in 2014. The measuring precision of TEC exceeds that obtained from GPS receiver data because the measurement is derived from unambiguous carrier phase estimates, not pseudorange estimates. The observation results from TT&C stations can provide real time regional ionosphere TEC estimation.

A joint tracking method for NSCC based on WLS algorithm

NASA Astrophysics Data System (ADS)

Luo, Ruidan; Xu, Ying; Yuan, Hong

2017-12-01

Navigation signal based on compound carrier (NSCC), has the flexible multi-carrier scheme and various scheme parameters configuration, which enables it to possess significant efficiency of navigation augmentation in terms of spectral efficiency, tracking accuracy, multipath mitigation capability and anti-jamming reduction compared with legacy navigation signals. Meanwhile, the typical scheme characteristics can provide auxiliary information for signal synchronism algorithm design. This paper, based on the characteristics of NSCC, proposed a kind of joint tracking method utilizing Weighted Least Square (WLS) algorithm. In this method, the LS algorithm is employed to jointly estimate each sub-carrier frequency shift with the frequency-Doppler linear relationship, by utilizing the known sub-carrier frequency. Besides, the weighting matrix is set adaptively according to the sub-carrier power to ensure the estimation accuracy. Both the theory analysis and simulation results illustrate that the tracking accuracy and sensitivity of this method outperforms the single-carrier algorithm with lower SNR.

Space weapon technology and policy

NASA Astrophysics Data System (ADS)

Hitchens, Theresa

2017-11-01

The military use of space, including in support of nuclear weapons infrastructure, has greatly increased over the past 30 years. In the current era, rising geopolitical tensions between the United States and Russia and China have led to assumptions in all three major space powers that warfighting in space now is inevitable, and possible because of rapid technological advancements. New capabilities for disrupting and destroying satellites include radio-frequency jamming, the use of lasers, maneuverable space objects and more capable direct-ascent anti-satellite weapons. This situation, however, threatens international security and stability among nuclear powers. There is a continuing and necessary role for diplomacy, especially the establishment of normative rules of behavior, to reduce risks of misperceptions and crisis escalation, including up to the use of nuclear weapons. U.S. policy and strategy should seek a balance between traditional military approaches to protecting its space assets and diplomatic tools to create a more secure space environment.

Analysis of interference of QPSK and QDPSK modulation signals by mathematical

NASA Astrophysics Data System (ADS)

Li, Dairuo; Xu, Kai

2017-03-01

In today's society, with the rapid development and extensive application of the information technology of the network central station and the integrated information system technology, information plays an important role in the military communication, mastering the information right to the competition Important role, how to protect one's own security, smooth access to and transmission of information, and to maximize the elimination of interference has become an important issue at home and abroad. QPSK modulation and its improved QPSK modulation as the mainstream signal modulation, the most widely used. In this paper, the principle of QPSK and QDPSK modulation and demodulation are introduced in this paper. Then, how to interfere with QPSK modulation signal is analyzed, and the interference of QPSK modulation signal is simulated by Matlab scripting program, which can be used in the next step. And to study the next step of anti-jamming measures provided the basis and preparatory work.

Distributed FBG sensors apply in spacecraft health monitoring

NASA Astrophysics Data System (ADS)

Huang, Xiujun; Zhang, Cuicui; Shi, Dele; Shen, Jingshi

2017-10-01

At present, Spacecraft manufacturing face with high adventure for its complicate structure, serious space environment and not maintained on orbit. When something wrong with spacecraft, monitoring its health state, supply health data in real time would assure quickly locate error and save more time to rescue it. For FBG sensor can distributed test several parameters such as temperature, strain, vibration and easily construct net. At same time, it has more advantages such as ant-radiate, anti-jamming, rodent-resistant and with long lifetime, which more fit for applying in space. In this paper, a spacecraft health monitor system based on FBG sensors is present, Firstly, spacecraft health monitor system and its development are introduced. Then a four channels FBG demodulator is design. At last, Temperature and strain detecting experiment is done. The result shows that the demodulator fully satisfied the need of spacecraft health monitor system.

Monolayer nanoparticle-covered liquid marbles derived from a sol-gel coating

NASA Astrophysics Data System (ADS)

Li, Xiaoguang; Wang, Yiqi; Huang, Junchao; Yang, Yao; Wang, Renxian; Geng, Xingguo; Zang, Duyang

2017-12-01

A sol-gel coating consisting of hydrophobic SiO2 nanoparticles (NPs) was used to produce monolayer NP-covered (mNPc) liquid marbles. The simplest approach was rolling a droplet on this coating, and an identifiable signet allowed determination of the coverage ratio of the resulting liquid marble. Alternatively, the particles were squeezed onto a droplet surface with two such coatings, generating surface buckling from interfacial NP jamming, and then a liquid marble was produced via a jamming-relief process in which water was added into the buckled droplet. This process revealed an ˜7% reduction in particle distance after interfacial jamming. The mNPc liquid marbles obtained by the two methods were transparent with smooth profiles, as naked droplets, and could be advantageously used in fundamental and applied researches for their unique functions.

Mean-field velocity difference model considering the average effect of multi-vehicle interaction

NASA Astrophysics Data System (ADS)

Guo, Yan; Xue, Yu; Shi, Yin; Wei, Fang-ping; Lü, Liang-zhong; He, Hong-di

2018-06-01

In this paper, a mean-field velocity difference model(MFVD) is proposed to describe the average effect of multi-vehicle interactions on the whole road. By stability analysis, the stability condition of traffic system is obtained. Comparison with stability of full velocity-difference (FVD) model and the completeness of MFVD model are discussed. The mKdV equation is derived from MFVD model through nonlinear analysis to reveal the traffic jams in the form of the kink-antikink density wave. Then the numerical simulation is performed and the results illustrate that the average effect of multi-vehicle interactions plays an important role in effectively suppressing traffic jam. The increase strength of the mean-field velocity difference in MFVD model can rapidly reduce traffic jam and enhance the stability of traffic system.

Jamming transitions in cancer

NASA Astrophysics Data System (ADS)

Oswald, Linda; Grosser, Steffen; Smith, David M.; Käs, Josef A.

2017-12-01

The traditional picture of tissues, where they are treated as liquids defined by properties such as surface tension or viscosity has been redefined during the last few decades by the more fundamental question: under which conditions do tissues display liquid-like or solid-like behaviour? As a result, basic concepts arising from the treatment of tissues as solid matter, such as cellular jamming and glassy tissues, have shifted into the current focus of biophysical research. Here, we review recent works examining the phase states of tissue with an emphasis on jamming transitions in cancer. When metastasis occurs, cells gain the ability to leave the primary tumour and infiltrate other parts of the body. Recent studies have shown that a linkage between an unjamming transition and tumour progression indeed exists, which could be of importance when designing surgery and treatment approaches for cancer patients.

GNSS Signal Authentication Via Power and Distortion Monitoring

NASA Astrophysics Data System (ADS)

Wesson, Kyle D.; Gross, Jason N.; Humphreys, Todd E.; Evans, Brian L.

2018-04-01

We propose a simple low-cost technique that enables civil Global Positioning System (GPS) receivers and other civil global navigation satellite system (GNSS) receivers to reliably detect carry-off spoofing and jamming. The technique, which we call the Power-Distortion detector, classifies received signals as interference-free, multipath-afflicted, spoofed, or jammed according to observations of received power and correlation function distortion. It does not depend on external hardware or a network connection and can be readily implemented on many receivers via a firmware update. Crucially, the detector can with high probability distinguish low-power spoofing from ordinary multipath. In testing against over 25 high-quality empirical data sets yielding over 900,000 separate detection tests, the detector correctly alarms on all malicious spoofing or jamming attacks while maintaining a <0.6% single-channel false alarm rate.

[Physicochemical and microbiological evaluation of 3 commercial guava jams (Psidium guajava L.)].

PubMed

López, R; Ramírez, A O; Graziani de Fariñas, L

2000-09-01

Four different production batches were taken from each brand. Samples were purchased from retail markets in Maracay, Cagua and Turmero. (Venezuela). The average physical and chemical values were: vacuum = 38.81 cm Hg; pH = 3.28; titrable acidity (%citric acid) = 0.59%; degree Brix = 67.24; reducing sugars = 55.28%; total sugars = 62.28, and the color parameters a = +14.44, b = +8.77 and L = 17.09. Molds, yeast and aerobic plate counts were lower than 10 UFC/g; it reveals an excellent microbiological quality of the product. The studied jams degree Brix and acidity fulfil COVENIN (1) requirements for jam products, but not pH range. In agreement with variance analysis, there were highly significance differences between the samples and among the shares of each sample for all physical and chemical properties evaluated.

Teen Bands to Battle on a National Stage: NAMM Expands Its SchoolJam Showcase with a Little Help from MENC

ERIC Educational Resources Information Center

Giordano, Geoff

2009-01-01

SchoolJam, a popular teen musicians' showcase in Texas that provides recognition for young performers as well as funding for their school music programs, is about to go nationwide. The competition, which NAMM, the International Music Products Association, brought to the United States from Germany in 2007, allows groups of musicians age 13 to 18 to…

Camouflage Traffic: Minimizing Message Delay for Smart Grid Applications under Jamming

DTIC Science & Technology

2014-04-01

technologies. To facilitate efficient information exchange, wireless networks have been proposed to be widely used in the smart grid. However, the jamming...attack that constantly broadcasts radio interference is a primary security threat to prevent the deployment of wireless networks in the smart grid. Hence... wireless communications, while at the same time providing latency guarantee for control messages. An open question is how to minimize message delay for

Flexible fiber in interaction with a dense granular flow close to the jamming transition

NASA Astrophysics Data System (ADS)

Algarra, Nicolas; Leang, Marguerite; Lazarus, Arnaud; Vandembroucq, Damien; Kolb, Evelyne

2017-06-01

We propose a new fluid/structure interaction in the unusual case of a dense granular medium flowing against an elastic fiber acting as a flexible intruder. We study experimentally the reconfiguration and the forces exerted on the flexible fiber produced by the flow at a constant and low velocity of a two-dimensional disordered packing of grains close but below the jamming transition.

Jamming in Mobile Networks: A Game-Theoretic Approach

DTIC Science & Technology

2013-03-01

general treatment of multiplayer differential games was presented by Starr and Ho [16], Leitmann [36], Vaisbord and Zhukovskiy [65], Zhukovskiy and...REPORT Jamming in mobile networks: A game -theoretic approach. 14. ABSTRACT 16. SECURITY CLASSIFICATION OF: In this paper, we address the problem of...model the intrusion as a pursuit-evasion game between a mobile jammer and a team of agents. First, we consider a differential game -theoretic approach

Modeling, Evaluation and Detection of Jamming Attacks in Time-Critical Wireless Applications

DTIC Science & Technology

2014-08-01

computing, modeling and analysis of wireless networks , network topol- ogy, and architecture design. Dr. Wang has been a Member of the Association for...important, yet open research question is how to model and detect jamming attacks in such wireless networks , where communication traffic is more time...against time-critical wireless networks with applications to the smart grid. In contrast to communication networks where packets-oriented metrics

Optimal Pricing and Power Allocation for Collaborative Jamming with Full Channel Knowledge in Wireless Sensor Networks

PubMed Central

Jeong, Dae-Kyo; Kim, Insook; Kim, Dongwoo

2017-01-01

This paper presents a price-searching model in which a source node (Alice) seeks friendly jammers that prevent eavesdroppers (Eves) from snooping legitimate communications by generating interference or noise. Unlike existing models, the distributed jammers also have data to send to their respective destinations and are allowed to access Alice’s channel if it can transmit sufficient jamming power, which is referred to as collaborative jamming in this paper. For the power used to deliver its own signal, the jammer should pay Alice. The price of the jammers’ signal power is set by Alice and provides a tradeoff between the signal and the jamming power. This paper presents, in closed-form, an optimal price that maximizes Alice’s benefit and the corresponding optimal power allocation from a jammers’ perspective by assuming that the network-wide channel knowledge is shared by Alice and jammers. For a multiple-jammer scenario where Alice hardly has the channel knowledge, this paper provides a distributed and interactive price-searching procedure that geometrically converges to an optimal price and shows that Alice by a greedy selection policy achieves certain diversity gain, which increases log-linearly as the number of (potential) jammers grows. Various numerical examples are presented to illustrate the behavior of the proposed model. PMID:29165373

Traffic flow behavior at a single-lane urban roundabout

NASA Astrophysics Data System (ADS)

Lakouari, N.; Oubram, O.; Ez-Zahraouy, H.; Cisneros-Villalobos, L.; Velásquez-Aguilar, J. G.

In this paper, we propose a stochastic cellular automata model to study the traffic behavior at a single-lane roundabout. Vehicles can enter the interior lane or exit from it via N intersecting lane, the boundary conditions are stochastic. The traffic is controlled by a self-organized scheme. It has turned out that depending on the rules of insertion to the roundabout, five distinct traffic phases can appear, namely, free flow, congestion, maximum current, jammed and gridlock. The transition between the free flow and the gridlock is forbidden. The density profiles are used to study the traffic pattern at the interior lane of the roundabout. In order to quantify the interactions between vehicles in the interior lane of the roundabout, the velocity correlation coefficient (VCC) is also studied. Besides, the spatiotemporal diagrams corresponding to the entry/exit lanes are derived numerically. Furthermore, we have investigated the effect of displaying signal (PIn), as the PIn decreases, the maximum current increases at the expense of the free flow and the jamming phase. Finally, we have investigated the effect of the braking probability P on the interior lane of the roundabout. We have found that the increase of P raises the spontaneous jam formation on the ring. Thus, enlarges the maximum current and the jamming phase while the free flow phase decreases.

Calling louder and longer: how bats use biosonar under severe acoustic interference from other bats.

PubMed

Amichai, Eran; Blumrosen, Gaddi; Yovel, Yossi

2015-12-22

Active-sensing systems such as echolocation provide animals with distinct advantages in dark environments. For social animals, however, like many bat species, active sensing can present problems as well: when many individuals emit bio-sonar calls simultaneously, detecting and recognizing the faint echoes generated by one's own calls amid the general cacophony of the group becomes challenging. This problem is often termed 'jamming' and bats have been hypothesized to solve it by shifting the spectral content of their calls to decrease the overlap with the jamming signals. We tested bats' response in situations of extreme interference, mimicking a high density of bats. We played-back bat echolocation calls from multiple speakers, to jam flying Pipistrellus kuhlii bats, simulating a naturally occurring situation of many bats flying in proximity. We examined behavioural and echolocation parameters during search phase and target approach. Under severe interference, bats emitted calls of higher intensity and longer duration, and called more often. Slight spectral shifts were observed but they did not decrease the spectral overlap with jamming signals. We also found that pre-existing inter-individual spectral differences could allow self-call recognition. Results suggest that the bats' response aimed to increase the signal-to-noise ratio and not to avoid spectral overlap. © 2015 The Author(s).

How do generalized jamming transitions affect collective migration in confluent tissues?

NASA Astrophysics Data System (ADS)

Manning, M. Lisa

Recent experiments have demonstrated that tissues involved in embryonic development, lung function, wound healing, and cancer progression are close to fluid-to-solid, or ``jamming'' transitions. Theoretical models for confluent 2D tissues have also been shown to exhibit continuous rigidity transitions. However, in vivobiological systems can differ in significant ways from the simple 2D models. For example, many tissues are three-dimensional, mechanically heterogeneous, and/or composed of mechanosensitive cells interspersed with extracellular matrix. We have extended existing models for confluent tissues to capture these features, and we find interesting predictions for collective cell motion that are ultimately related to an underlying generalized jamming transition. For example, in 2D, we find that heterogeneous mixtures of cells spontaneously self-organize into rigid regions of stiffer cells interspersed with string-like groups of soft cells, reminiscent of cellular streaming seen in cancer. We also find that alignment interactions (of the sort often explored in self-propelled particle models) alter the transition and generate interesting flocked liquid and flocked solid collective migration patterns. Our model predicts that 3D tissues also exhibit a jamming transition governed by cell shape, as well as history-dependent aging, and we are currently exploring whether ECM-like interactions in 3D models might help explain compressional stiffening seen in experiments on human tissue.

Large-scale structure of randomly jammed spheres

NASA Astrophysics Data System (ADS)

Ikeda, Atsushi; Berthier, Ludovic; Parisi, Giorgio

2017-05-01

We numerically analyze the density field of three-dimensional randomly jammed packings of monodisperse soft frictionless spherical particles, paying special attention to fluctuations occurring at large length scales. We study in detail the two-point static structure factor at low wave vectors in Fourier space. We also analyze the nature of the density field in real space by studying the large-distance behavior of the two-point pair correlation function, of density fluctuations in subsystems of increasing sizes, and of the direct correlation function. We show that such real space analysis can be greatly improved by introducing a coarse-grained density field to disentangle genuine large-scale correlations from purely local effects. Our results confirm that both Fourier and real space signatures of vanishing density fluctuations at large scale are absent, indicating that randomly jammed packings are not hyperuniform. In addition, we establish that the pair correlation function displays a surprisingly complex structure at large distances, which is however not compatible with the long-range negative correlation of hyperuniform systems but fully compatible with an analytic form for the structure factor. This implies that the direct correlation function is short ranged, as we also demonstrate directly. Our results reveal that density fluctuations in jammed packings do not follow the behavior expected for random hyperuniform materials, but display instead a more complex behavior.

Optimal Pricing and Power Allocation for Collaborative Jamming with Full Channel Knowledge in Wireless Sensor Networks.

PubMed

Jeong, Dae-Kyo; Kim, Insook; Kim, Dongwoo

2017-11-22

This paper presents a price-searching model in which a source node (Alice) seeks friendly jammers that prevent eavesdroppers (Eves) from snooping legitimate communications by generating interference or noise. Unlike existing models, the distributed jammers also have data to send to their respective destinations and are allowed to access Alice's channel if it can transmit sufficient jamming power, which is referred to as collaborative jamming in this paper. For the power used to deliver its own signal, the jammer should pay Alice. The price of the jammers' signal power is set by Alice and provides a tradeoff between the signal and the jamming power. This paper presents, in closed-form, an optimal price that maximizes Alice's benefit and the corresponding optimal power allocation from a jammers' perspective by assuming that the network-wide channel knowledge is shared by Alice and jammers. For a multiple-jammer scenario where Alice hardly has the channel knowledge, this paper provides a distributed and interactive price-searching procedure that geometrically converges to an optimal price and shows that Alice by a greedy selection policy achieves certain diversity gain, which increases log-linearly as the number of (potential) jammers grows. Various numerical examples are presented to illustrate the behavior of the proposed model.

Fish community structure in natural and engineered habitats in the Kansas River

USGS Publications Warehouse

White, K.; Gerken, J.; Paukert, Craig P.; Makinster, Andrew S.

2010-01-01

We investigated fish assemblage structure in engineered (rip-rap) and natural habitats (log jams and mud banks) in the Kansas River USA to determine if natural structures had higher abundance and diversity of fishes at a local spatial scale. A total of 439 randomly selected sites were boat electrofished from May to August 2005 and 2006. Mean species diversity and richness were significantly higher in rip-rap than log jams and mud banks. Mean relative abundance (CPUE; number of fish collected per hour electrofishing) of six of the 15 most common fishes (>1% of total catch) were most abundant in rip-rap, two were most abundant in log jams, and none in mud banks. Rip-rap had the highest relative abundance of fluvial specialist and macrohabitat generalists, whereas mean CPUE of fluvial dependents was highest in log jams. Although a discriminant function analysis indicated that nine size classes (eight species) discriminated among three habitat types, the high misclassification rate (38%) suggested a high degree of fish assemblage overlap among the habitats. Although previous work has suggested that engineered structures (rip-rap) and urbanization are linked to reduced biotic diversity or reduced growth of fish species, our results suggest that at a local scale rip-rap may not have the same negative impacts on fish assemblages.

Fish community structure in natural and engineered habitats in the Kansas river

USGS Publications Warehouse

White, K.; Gerken, J.; Paukert, C.; Makinster, A.

2010-01-01

We investigated fish assemblage structure in engineered (rip-rap) and natural habitats (log jams and mud banks) in the Kansas River USA to determine if natural structures had higher abundance and diversity of fishes at a local spatial scale. A total of 439 randomly selected sites were boat electrofished from May to August 2005 and 2006. Mean species diversity and richness were significantly higher in rip-rap than log jams and mud banks. Mean relative abundance (CPUE; number of fish collected per hour electrofishing) of six of the 15 most common fishes (>1% of total catch) were most abundant in rip-rap, two were most abundant in log jams, and none in mud banks. Rip-rap had the highest relative abundance of fluvial specialist and macrohabitat generalists, whereas mean CPUE of fluvial dependents was highest in log jams. Although a discriminant function analysis indicated that nine size classes (eight species) discriminated among three habitat types, the high misclassification rate (38%) suggested a high degree of fish assemblage overlap among the habitats. Although previous work has suggested that engineered structures (rip-rap) and urbanization are linked to reduced biotic diversity or reduced growth of fish species, our results suggest that at a local scale rip-rap may not have the same negative impacts on fish assemblages.

The jamming avoidance response in the weakly electric fish Eigenmannia

NASA Astrophysics Data System (ADS)

Heiligenberg, Walter

1980-10-01

This study analyzes the algorithm by which the animal's nervous system evaluates spatially distributed temporal patterns of electroreceptive information. The outcome of this evaluation controls the jamming avoidance response, which is a shift in the animal's electric organ discharge frequency away from similar foreign frequencies. The encoding of “behaviorally relevant” stimulus variables by electroreceptors and the central computation of their messages are investigated by combined behavioral and neurophysiological strategies.

Technique for Geolocation of EMI Emitters by O3B Satellites

DTIC Science & Technology

2016-06-01

1.  Why EMI/Jamming Is an Issue for the DOD ..............................6  2.  How Jamming Occurs...professor in the field. I would also like to thank O3b Networks, particularly Ken Mentasti and J.J. Shaw , for their extensive support by providing...breaking the primary research question into pieces and developing the subject, it is first important to develop what SATCOM EMI is and why it is an issue

Physics and (patho)physiology in confined flows: from colloidal patterns to cytoplasmic rheology and sickle cell anemia

NASA Astrophysics Data System (ADS)

Mahadevan, L.

2015-03-01

I will discuss a few problems that involve the interaction of fluids and solids in confined spaces. (i) Jamming in pressure-driven suspension flows that show a transition from Stokes flows to Darcy flows as the solids start to lock, as in evaporative patterning in colloids (e.g. coffee stain formation) .(ii) Jamming and clogging of red blood cells, as in sickle-cell pathophysiology, with implications for other diseases that involve jamming. (iii) The mechanical response of crowded networks of filaments bathed in a fluid, as in the cytoskeleton, that can be described by poroelasticity theory. In each case, I will show how simple theories of multiphase flow and deformation can be used to explain a range of experimental observations, while failing to account for others, along with some thoughts on how to improve them.

Synchronized flow in oversaturated city traffic.

PubMed

Kerner, Boris S; Klenov, Sergey L; Hermanns, Gerhard; Hemmerle, Peter; Rehborn, Hubert; Schreckenberg, Michael

2013-11-01

Based on numerical simulations with a stochastic three-phase traffic flow model, we reveal that moving queues (moving jams) in oversaturated city traffic dissolve at some distance upstream of the traffic signal while transforming into synchronized flow. It is found that, as in highway traffic [Kerner, Phys. Rev. E 85, 036110 (2012)], such a jam-absorption effect in city traffic is explained by a strong driver's speed adaptation: Time headways (space gaps) between vehicles increase upstream of a moving queue (moving jam), resulting in moving queue dissolution. It turns out that at given traffic signal parameters, the stronger the speed adaptation effect, the shorter the mean distance between the signal location and the road location at which moving queues dissolve fully and oversaturated traffic consists of synchronized flow only. A comparison of the synchronized flow in city traffic found in this Brief Report with synchronized flow in highway traffic is made.

Large woody debris and land management in California's hardwood-dominated watersheds.

PubMed

Opperman, Jeff J

2005-03-01

Although large woody debris (LWD) has been studied extensively in conifer-dominated watersheds, relatively little is known about LWD in hardwood-dominated watersheds. Field surveys of 32 hardwood-dominated stream reaches in northern coastal California revealed that levels of LWD varied with land ownership and that living trees strongly influenced debris jam formation. Almost half of the channel-spanning debris jams, which stored the most wood and were most likely to form a pool, were formed behind a key piece that was still living. These living key pieces might provide greater longevity and stability than would otherwise be expected from hardwood LWD. Compared to streams on private land, streams on public land had significantly greater LWD loading and debris-jam frequency. Land management practices that remove wood from streams might be contributing to the degradation of salmonid habitat in California's hardwood-dominated watersheds.

Stochastic Car-Following Model for Explaining Nonlinear Traffic Phenomena

NASA Astrophysics Data System (ADS)

Meng, Jianping; Song, Tao; Dong, Liyun; Dai, Shiqiang

There is a common time parameter for representing the sensitivity or the lag (response) time of drivers in many car-following models. In the viewpoint of traffic psychology, this parameter could be considered as the perception-response time (PRT). Generally, this parameter is set to be a constant in previous models. However, PRT is actually not a constant but a random variable described by the lognormal distribution. Thus the probability can be naturally introduced into car-following models by recovering the probability of PRT. For demonstrating this idea, a specific stochastic model is constructed based on the optimal velocity model. By conducting simulations under periodic boundary conditions, it is found that some important traffic phenomena, such as the hysteresis and phantom traffic jams phenomena, can be reproduced more realistically. Especially, an interesting experimental feature of traffic jams, i.e., two moving jams propagating in parallel with constant speed stably and sustainably, is successfully captured by the present model.

Jammed Clusters and Non-locality in Dense Granular Flows

NASA Astrophysics Data System (ADS)

Kharel, Prashidha; Rognon, Pierre

We investigate the micro-mechanisms underpinning dense granular flow behaviour from a series of DEM simulations of pure shear flows of dry grains. We observe the development of transient clusters of jammed particles within the flow. Typical size of such clusters is found to scale with the inertial number with a power law that is similar to the scaling of shear-rate profile relaxation lengths observed previously. Based on the simple argument that transient clusters of size l exist in the dense flow regime, the formulation of steady state condition for non-homogeneous shear flow results in a general non-local relation, which is similar in form to the non-local relation conjectured for soft glassy flows. These findings suggest the formation of jammed clusters to be the key micro-mechanism underpinning non-local behaviour in dense granular flows. Particles and Grains Laboratory, School of Civil Engineering, The University of Sydney, Sydney, NSW 2006, Australia.

Fractal free energy landscapes in structural glasses.

PubMed

Charbonneau, Patrick; Kurchan, Jorge; Parisi, Giorgio; Urbani, Pierfrancesco; Zamponi, Francesco

2014-04-24

Glasses are amorphous solids whose constituent particles are caged by their neighbours and thus cannot flow. This sluggishness is often ascribed to the free energy landscape containing multiple minima (basins) separated by high barriers. Here we show, using theory and numerical simulation, that the landscape is much rougher than is classically assumed. Deep in the glass, it undergoes a 'roughness transition' to fractal basins, which brings about isostaticity and marginal stability on approaching jamming. Critical exponents for the basin width, the weak force distribution and the spatial spread of quasi-contacts near jamming can be analytically determined. Their value is found to be compatible with numerical observations. This advance incorporates the jamming transition of granular materials into the framework of glass theory. Because temperature and pressure control what features of the landscape are experienced, glass mechanics and transport are expected to reflect the features of the topology we discuss here.

Synchronized flow in oversaturated city traffic

NASA Astrophysics Data System (ADS)

Kerner, Boris S.; Klenov, Sergey L.; Hermanns, Gerhard; Hemmerle, Peter; Rehborn, Hubert; Schreckenberg, Michael

2013-11-01

Based on numerical simulations with a stochastic three-phase traffic flow model, we reveal that moving queues (moving jams) in oversaturated city traffic dissolve at some distance upstream of the traffic signal while transforming into synchronized flow. It is found that, as in highway traffic [Kerner, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.85.036110 85, 036110 (2012)], such a jam-absorption effect in city traffic is explained by a strong driver's speed adaptation: Time headways (space gaps) between vehicles increase upstream of a moving queue (moving jam), resulting in moving queue dissolution. It turns out that at given traffic signal parameters, the stronger the speed adaptation effect, the shorter the mean distance between the signal location and the road location at which moving queues dissolve fully and oversaturated traffic consists of synchronized flow only. A comparison of the synchronized flow in city traffic found in this Brief Report with synchronized flow in highway traffic is made.

Traffic on complex networks: Towards understanding global statistical properties from microscopic density fluctuations

NASA Astrophysics Data System (ADS)

Tadić, Bosiljka; Thurner, Stefan; Rodgers, G. J.

2004-03-01

We study the microscopic time fluctuations of traffic load and the global statistical properties of a dense traffic of particles on scale-free cyclic graphs. For a wide range of driving rates R the traffic is stationary and the load time series exhibits antipersistence due to the regulatory role of the superstructure associated with two hub nodes in the network. We discuss how the superstructure affects the functioning of the network at high traffic density and at the jamming threshold. The degree of correlations systematically decreases with increasing traffic density and eventually disappears when approaching a jamming density Rc. Already before jamming we observe qualitative changes in the global network-load distributions and the particle queuing times. These changes are related to the occurrence of temporary crises in which the network-load increases dramatically, and then slowly falls back to a value characterizing free flow.

The Wonderful World of Active Many-Particle Systems

NASA Astrophysics Data System (ADS)

Helbing, Dirk

Since the subject of traffic dynamics has captured the interest of physicists, many astonishing effects have been revealed and explained. Some of the questions now understood are the following: Why are vehicles sometimes stopped by so-called ``phantom traffic jams'', although they all like to drive fast? What are the mechanisms behind stop-and-go traffic? Why are there several different kinds of congestion, and how are they related? Why do most traffic jams occur considerably before the road capacity is reached? Can a temporary reduction of the traffic volume cause a lasting traffic jam? Why do pedestrians moving in opposite directions normally organize in lanes, while nervous crowds are ``freezing by heating''? Why do panicking pedestrians produce dangerous deadlocks? All these questions have been answered by applying and extending methods from statistical physics and non-linear dynamics to self-driven many-particle systems.

Constraint counting for frictional jamming

NASA Astrophysics Data System (ADS)

Quint, D. A.; Henkes, S.; Schwarz, J. M.

2012-02-01

While the frictionless jamming transition has been intensely studied in recent years, more realistic frictional packings are less well understood. In frictionless sphere packings, the transition is predicted by a simple mean-field constraint counting argument, the isostaticity argument. For frictional packings, a modified constraint counting argument, which includes slipping contacts at the Coulomb threshold, has had limited success in accounting for the transition. We propose that the frictional jamming transition is not mean field and is triggered by the nucleation of unstable regions, which are themselves dynamical objects due to the Coulomb criterion. We create frictional packings using MD simulations and test for the presence and shape of rigid clusters with the pebble game to identify the partition of the packing into stable and unstable regions. To understand the dynamics of these unstable regions we follow perturbations at contacts crucial to the stability of the ``frictional house of cards.''

Strain-level genetic diversity of Methylophaga nitratireducenticrescens confers plasticity to denitrification capacity in a methylotrophic marine denitrifying biofilm

PubMed Central

Geoffroy, Valérie; Payette, Geneviève; Mauffrey, Florian; Lestin, Livie; Constant, Philippe

2018-01-01

Background The biofilm of a methanol-fed, fluidized denitrification system treating a marine effluent is composed of multi-species microorganisms, among which Hyphomicrobium nitrativorans NL23 and Methylophaga nitratireducenticrescens JAM1 are the principal bacteria involved in the denitrifying activities. Strain NL23 can carry complete nitrate (NO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${}_{3}^{-}$\\end{document}3−) reduction to N2, whereas strain JAM1 can perform 3 out of the 4 reduction steps. A small proportion of other denitrifiers exists in the biofilm, suggesting the potential plasticity of the biofilm in adapting to environmental changes. Here, we report the acclimation of the denitrifying biofilm from continuous operating mode to batch operating mode, and the isolation and characterization from the acclimated biofilm of a new denitrifying bacterial strain, named GP59. Methods The denitrifying biofilm was batch-cultured under anoxic conditions. The acclimated biofilm was plated on Methylophaga specific medium to isolate denitrifying Methylophaga isolates. Planktonic cultures of strains GP59 and JAM1 were performed, and the growth and the dynamics of NO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${}_{3}^{-}$\\end{document}3−, nitrite (NO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${}_{2}^{-}$\\end{document}2−) and N2O were determined. The genomes of strains GP59 and JAM1 were sequenced and compared. The transcriptomes of strains GP59 and JAM1 were derived from anoxic cultures. Results During batch cultures of the biofilm, we observed the disappearance of H. nitrativorans NL23 without affecting the denitrification performance. From the acclimated biofilm, we isolated strain GP59 that can perform, like H. nitrativorans NL23, the complete denitrification pathway. The GP59 cell concentration in the acclimated biofilm was 2–3 orders of magnitude higher than M. nitratireducenticrescens JAM1 and H. nitrativorans NL23. Genome analyses revealed that strain GP59 belongs to the species M. nitratireducenticrescens. The GP59 genome shares more than 85% of its coding sequences with those of strain JAM1. Based on transcriptomic analyses of anoxic cultures, most of these common genes in strain GP59 were expressed at similar level than their counterparts in strain JAM1. In contrast to strain JAM1, strain GP59 cannot reduce NO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${}_{3}^{-}$\\end{document}3− under oxic culture conditions, and has a 24-h lag time before growth and NO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${}_{3}^{-}$\\end{document}3− reduction start to occur in anoxic cultures, suggesting that both strains regulate differently the expression of their denitrification genes. Strain GP59 has the ability to reduce NO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${}_{2}^{-}$\\end{document}2− as it carries a gene encoding a NirK-type NO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{upgreek} \\usepackage{mathrsfs} \\setlength{\\oddsidemargin}{-69pt} \\begin{document} }{}${}_{2}^{-}$\\end{document}2− reductase. Based on the CRISPR sequences, strain GP59 did not emerge from strain JAM1 during the biofilm batch cultures but rather was present in the original biofilm and was enriched during this process. Discussion These results reinforce the unique trait of the species M. nitratireducenticrescens among the Methylophaga genus as facultative anaerobic bacterium. These findings also showed the plasticity of denitrifying population of the biofilm in adapting to anoxic marine environments of the bioreactor. PMID:29707436

Abundance and Morphological Effects of Large Woody Debris in Forested Basins of Southern Andes

NASA Astrophysics Data System (ADS)

Andreoli, A.; Comiti, F.; Lenzi, M. A.

2006-12-01

The Southern Andes mountain range represents an ideal location for studying large woody debris (LWD) in streams draining forested basins thanks to the presence of both pristine and managed woodland, and to the general low level of human alteration of stream corridors. However, no published investigations have been performed so far in such a large region. The investigated sites of this research are three basins (9-13 km2 drainage area, third-order channels) covered by Nothofagus forests: two of them are located in the Southern Chilean Andes (the Tres Arroyos in the Malalcahuello National Reserve and the Rio Toro within the Malleco Natural Reserve) and one basin lies in the Argentinean Tierra del Fuego (the Buena Esperanza basin, near the city of Ushuaia). Measured LWD were all wood pieces larger than 10 cm in diameter and 1 m in length, both in the active channel and in the adjacent active floodplain. Pieces forming log jams were all measured and the geometrical dimensions of jams were taken. Jam type was defined based on Abbe and Montgomery (2003) classification. Sediment stored behind log-steps and valley jams was evaluated approximating the sediment accumulated to a solid wedge whose geometrical dimensions were measured. Additional information relative to each LWD piece were recorded during the field survey: type (log, rootwad, log with rootwads attached), orientation to flow, origin (floated, bank erosion, landslide, natural mortality, harvest residuals) and position (log-step, in-channel, channel-bridging, channel margins, bankfull edge). In the Tres Arroyos, the average LWD volume stored within the bankfull channel is 710 m3 ha-1. The average number of pieces is 1,004 per hectare of bankfull channel area. Log-steps represent about 22% of all steps, whereas the elevation loss due to LWD (log-steps and valley jams) results in 27% loss of the total stream potential energy. About 1,600 m3 of sediment (assuming a porosity of 20%) is stored in the main channel behind LWD structures approximately, i.e. 1,000 m3 per km of channel length, corresponding to approximately 150% of the annual sediment yield. In the Rio Toro, the average LWD volume and number of elements stored are much less, respectively 117 m3 ha-1 and 215 pieces ha-1. Neither log-steps or valley jams were observed and the longitudinal profile appear not affected by LWD, and no sediment storage can be attributed to woody debris. The low LWD storage and impact in this channel is likely due to the general stability of its hillslopes, in contrast to the Tres Arroyos where extensive landslides and debris flows convey a great deal of wood into the stream. Finally, in the Buena Esperanza, the average LWD volume stored in the active channel is quite low (120 m3 ha-1, but the average number of pieces is the highest with 1,397 pieces ha-1. This is due to the smaller dimensions of LWD elements delivered by trees growing in a colder climate as that characterizing the Tierra del Fuego. The morphological influence of wood in this channel is however very important, with the presence of large valley jams and high log-steps imparting the channel a macro-scale stepped profile with a total energy dissipation due to LWD (log-steps and valley jams) of about 24 % of the stream potential energy. The sediment stored behind log-steps and valley jams results to be about 1,290 m3, i.e. 700 m3 km-1, but unfortunately no values of sediment yields are available for this basin.

Ice Engineering: Ice Jams, Winter 2002-2003

DTIC Science & Technology

2004-07-01

located between Caribou and Fort Fairfield, and from Presque Isle and Washburn (NWS 2003i). Of the seven, four were reported in December and three...the towns of Washburn and Presque Isle ) was estimated to be one-quarter of a mile long in December. This jam remained in place until 21 April 2003...then appeared to break in half, sending the downstream floe of ice southeast through the town of Presque Isle while the most upstream section of

Defense AR Journal, Volume 15, Number 1, April 2008

DTIC Science & Technology

2008-04-01

Beavers William Ruta DAUAA Research Paper Competition: 3rd Place Employing Organizational Modeling & Simulation of the KC-135 Depot’s Flight Controls Maj...AttAck munition SYStemS (jAmS) Project office imProvinG SuPPort to the wArfiGhter Barry Beavers and William Ruta The Joint Attack Munition Systems...William Ruta . This paper examines how the JAMS Project Office improved support to the warfighter with its implementation of the Life Cycle

Geomorphic and riparian forest influences on characteristics of large wood and large-wood jams in old-growth and second-growth forests in Northern Michigan, USA

Treesearch

Arthur E.L. Morris; P. Charles Goebel; Brian J. Palik

2007-01-01

Large wood (LW; pieces with diameter greater than 10 cm and length greater than 1 m) and large-wood jams (LWJs; two or more pieces of LW in contact with each other) are important components of stream ecosystems that are often distributed along stream channels in response to geomorphic and riparian forest factors that interact hierarchically. As a result, information on...

The Vulnerabilities of Unmanned Aircraft System Common Data Links to Electronic Attack

DTIC Science & Technology

2010-06-11

jamming, radar acquisition, and radar tracking (US Joint Forces Command 2009b, 101). Electromagnetic Interference ( EMI ). Any electromagnetic...has a range of up to 125 kilometers, and can remain airborne for up to 6 hours (see figure 6). The Shadow 200 is launched using a trailer mounted...disruption by EMI and friendly EW jamming systems. Second, FM 3-04.115 is the only publication that addresses counter-UAS threats and how enemy forces may

77 FR 73732 - In the Matter of Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-11

...'ida in Iraq, aka Jam'at al Tawhid wa'al-Jihad, aka The Monotheism and Jihad Group, aka The al-Zarqawi Network, aka al-Tawhid, aka Tanzim Qa`idat al-Jihad fi Bilad al-Rafidayn, aka The Organization of al-Jihad... Rivers, aka al-Qaida of Jihad Organization in the Land of the Two Rivers, aka al- Qaida Group of Jihad in...

77 FR 73732 - In the Matter of the Amendment of the Designation of al-Qa'ida in Iraq, aka Jam'at al Tawhid wa...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-11

...-Qa'ida in Iraq, aka Jam'at al Tawhid wa'al-Jihad, aka The Monotheism and Jihad Group, aka The al-Zarqawi Network, aka al-Tawhid, aka Tanzim Qa`idat al-Jihad fi Bilad al-Rafidayn, aka The Organization of... Group of Jihad in Iraq, aka al-Qaida Group of Jihad in the Land of the Two Rivers, aka The Organization...

Blind Demodulation of Pass Band OFDMA Signals and Jamming Battle Damage Assessment Utilizing Link Adaptation

DTIC Science & Technology

2014-03-27

Access (OFDMA) signal so that jamming effectiveness can be assessed; referred to in this research as Battle Damage Assessment ( BDA ). The research extends...the 802.16 Wireless Metropolitan Area Network (MAN) OFDMA standard, and presents a novel method for performing BDA via observation of Sub Carrier (SC...interferer is also evaluated where the blind demodulator’s performance is degraded. BDA is achieved via observing SC LA modulation behavior of the

Coherent detection of frequency-hopped quadrature modulations in the presence of jamming. II - QPR Class I modulation. [Quadrature Partial Response

NASA Technical Reports Server (NTRS)

Simon, M. K.

1981-01-01

This paper considers the performance of quadrature partial response (QPR) in the presence of jamming. Although a QPR system employs a single sample detector in its receiver, while quadrature amplitude shift keying (or quadrature phase shift keying) requires a matched-filter type of receiver, it is shown that the coherent detection performances of the two in the presence of the intentional jammer have definite similarities.

Flow-sediment-large woody debris interplay: Introducing an appropriately scaled laboratory experiment

NASA Astrophysics Data System (ADS)

Friedrich, H.; Spreitzer, G.; Tunnicliffe, J. F.

2017-12-01

The morphology of steep (>0.01 m/m) forested streams is governed not only by water-sediment interplay, but also by accumulations of coarse and fine organic debris. In this project we look at the jamming dynamics (formation, persistence and hydraulic feedbacks) of large woody debris with the help of scaled laboratory experiments. In New Zealand, the recruitment of wood from both natural tree-fall and forest harvesting has led to obstruction of culverts, bridges and other river constrictions. Understanding the dynamics of jam formation and persistence is important for harvest practice guidelines, management of sediment accumulation, as well as establishing impacts to habitat and infrastructure. In this study, we provide the context of our work, present our experimental setup for studying the complex flow-sediment-wood interactions and present some initial results. In our experimental setup, we varied feed rates of sediment and organic fine material in order to establish concentration thresholds for jam formation, and development of sediment retention capacity upstream of the jam. Large woody debris accumulation is studied for different blocking scenarios, and the effect on sediment transport is measured. Sediment quantities and changes in channel bed morphology upstream of the critical cross section are evaluated, together with resulting backwater effects, and associated energy losses. In the long term, our results will inform our understanding of the processes that take place from the mobilization of woody debris to accumulation.

Echolocating bats rely on audiovocal feedback to adapt sonar signal design.

PubMed

Luo, Jinhong; Moss, Cynthia F

2017-10-10

Many species of bat emit acoustic signals and use information carried by echoes reflecting from nearby objects to navigate and forage. It is widely documented that echolocating bats adjust the features of sonar calls in response to echo feedback; however, it remains unknown whether audiovocal feedback contributes to sonar call design. Audiovocal feedback refers to the monitoring of one's own vocalizations during call production and has been intensively studied in nonecholocating animals. Audiovocal feedback not only is a necessary component of vocal learning but also guides the control of the spectro-temporal structure of vocalizations. Here, we show that audiovocal feedback is directly involved in the echolocating bat's control of sonar call features. As big brown bats tracked targets from a stationary position, we played acoustic jamming signals, simulating calls of another bat, timed to selectively perturb audiovocal feedback or echo feedback. We found that the bats exhibited the largest call-frequency adjustments when the jamming signals occurred during vocal production. By contrast, bats did not show sonar call-frequency adjustments when the jamming signals coincided with the arrival of target echoes. Furthermore, bats rapidly adapted sonar call design in the first vocalization following the jamming signal, revealing a response latency in the range of 66 to 94 ms. Thus, bats, like songbirds and humans, rely on audiovocal feedback to structure sonar signal design.

Constraints and vibrations in static packings of ellipsoidal particles.

PubMed

Schreck, Carl F; Mailman, Mitch; Chakraborty, Bulbul; O'Hern, Corey S

2012-06-01

We numerically investigate the mechanical properties of static packings of frictionless ellipsoidal particles in two and three dimensions over a range of aspect ratio and compression Δφ. While amorphous packings of spherical particles at jamming onset (Δφ=0) are isostatic and possess the minimum contact number z_{iso} required for them to be collectively jammed, amorphous packings of ellipsoidal particles generally possess fewer contacts than expected for collective jamming (z

Preparation and radar absorptive properties of BaFe12O19 -coated glass fiber

NASA Astrophysics Data System (ADS)

Jia, F.; Xu, M.; Bao, H. Q.; Cui, K.; Zhang, F.

2016-07-01

Traditional passive jamming materials such as chaff and foil showed some limitations in use because they can only reflect the electromagnetic wave. Therefore, to develop a kind of absorptive passive jamming material to make up for deficiencies of traditional passive jamming materials and improve the jamming efficiency is of great significance. In this paper, the BaFe12O19-coated glass fiber, used as a kind of radar absorptive chaff, was prepared by sol-gel dip-coating method. The effects of heat treatment temperature, heat treatment time and coating times on film quality, tensile strength and attenuation efficiency of the samples were discussed. The study shows that an increase of the heat treatment temperature and an extension of the heat treatment time is conducive to the growth of barium ferrite grain, while they would introduce the loss of chaff strength at the same time. In addition, multi-coating process can improve the film quality and attenuation efficiency of the sample. Data show that the 10 times coated samples have a best reflectivity of (15GHz, -6.65dB) and the bandwidth of reflectivity lower than -5dB is11.8 GHz. According to the test results, the prepared material has certain attenuation efficiency in the range of 2GHz-18GHz, having a high practical value.

Large wood dynamics and biophysical consequences for riparian forests: A comparison of an unconfined alluvial river in a temperate rainforest and a bedrock confined river in a semi-arid South African savanna.

NASA Astrophysics Data System (ADS)

Latterell, J. J.; Pettit, N. E.; Naiman, R. J.

2005-05-01

Large wood shapes the geomorphology and ecology of rivers. We determined the origin, distribution, and fate of large wood in two rivers from contrasting environments. The Queets is an unstable temperate, rainforest river running from the Olympic Mountains (USA) through a glacial valley with colossal trees. In most years, the channel erodes a variety of forested landforms which forms jams that sculpt habitats. Many are displaced in a few years. Remaining jams initiate landform development and forest renewal. Thus, wood is stockpiled in the floodplain where it may become buried. Channel movements recapture most logs within 50 years. In contrast, the Sabie is a perennial river running through a confined bedrock channel in a fire-prone semi-arid South African savanna. Riparian trees are relatively small and many sink in water. A recent flood (February 2000) devastated the riparian forest, introducing wood to the channel. Jams formed on toppled trees, transported logs, and bedrock outcrops. Many trees survived and resprouted. Jams facilitated the establishment of woody plant seedlings and the intrusion of fire into riparian areas. Sunken wood formed unique depositional features. The Queets and Sabie rivers are strikingly different systems. However, large wood appears to promote the renewal and development of complex riparian forests in both rivers.

Thermophilic aeration of cattle slurry with whey and/or jam wastes.

PubMed

Heinonen-Tanski, Helvi; Kiuru, Tapio; Ruuskanen, Juhani; Korhonen, Kari; Koivunen, Jari; Ruokojärvi, Arja

2005-01-01

Thermophilic aeration of cattle slurry and food industrial by-products was studied with the aim to improve hygienic qualities of the slurry so that it could be used as a safe fertiliser for berries to be eaten raw. We also wanted to study if the process would be energetically favourable in an arctic climate. Cattle slurry alone or with whey and/or jam waste was treated. The tests were done in a well heat-insulated reactor with a 10 m(3) volume. Temperature increases up to over 70 degrees C could be recorded in 19 days even though some processes were carried out in winter time when the ambient air temperature was less than 0 degrees C. The heat energy formed was higher than the electrical energy needed to carry out the aeration. The hygienic qualities of the aerated product were good with only minor nitrogen losses. The end product could be useful as a fertiliser and soil improving compound to increase the organic matter content of agricultural soil. Cattle slurry alone was well suited as the raw material if attaining a high temperature was the main goal. A part of slurry could be replaced with food-industrial side products. Whey waste suited better for co-composting than jam waste but the mixture of whey, jam waste, and slurry was optimal for composting.

Delineation of the Clinical, Molecular and Cellular Aspects of Novel JAM3 Mutations Underlying the Autosomal Recessive Hemorrhagic Destruction of the Brain, Subependymal Calcification and Congenital Cataracts

PubMed Central

Akawi, Nadia A.; Canpolat, Fuat E.; White, Susan M.; Quilis-Esquerra, Josep; Sanchez, Martin Morales; Gamundi, Maria José; Mochida, Ganeshwaran H.; Walsh, Christopher A.; Ali, Bassam R.; Al-Gazali, Lihadh

2014-01-01

We have recently shown that the hemorrhagic destruction of the brain, subependymal calcification and congenital cataracts is caused by biallelic mutations in the gene encoding junctional adhesion molecule 3 (JAM3) protein. Affected members from three new families underwent detailed clinical examination including imaging of the brain. Affected individuals presented with a distinctive phenotype comprising hemorrhagic destruction of the brain, subependymal calcification and congenital cataracts. All patients had a catastrophic clinical course resulting in death in 7 out of 10 affected individuals. Sequencing the coding exons of JAM3 revealed three novel homozygous mutations: c.2T>G (p.M1R), c.346G>A (p.E116K) and c.656G>A (p.C219Y). The p.M1R mutation affects the start codon and therefore is predicted to impair protein synthesis. Cellular studies showed that the p.C219Y mutation resulted in a significant retention of the mutated protein in the endoplasmic reticulum, suggesting a trafficking defect. The p.E116K mutant traffics normally to the plasma membrane as the wild type and may have lost its function due to the lack of interaction with an interacting partner. Our data further support the importance of JAM3 in the development and function of the vascular system and the brain. PMID:23255084

Evaluation method based on the image correlation for laser jamming image

NASA Astrophysics Data System (ADS)

Che, Jinxi; Li, Zhongmin; Gao, Bo

2013-09-01

The jamming effectiveness evaluation of infrared imaging system is an important part of electro-optical countermeasure. The infrared imaging devices in the military are widely used in the searching, tracking and guidance and so many other fields. At the same time, with the continuous development of laser technology, research of laser interference and damage effect developed continuously, laser has been used to disturbing the infrared imaging device. Therefore, the effect evaluation of the infrared imaging system by laser has become a meaningful problem to be solved. The information that the infrared imaging system ultimately present to the user is an image, so the evaluation on jamming effect can be made from the point of assessment of image quality. The image contains two aspects of the information, the light amplitude and light phase, so the image correlation can accurately perform the difference between the original image and disturbed image. In the paper, the evaluation method of digital image correlation, the assessment method of image quality based on Fourier transform, the estimate method of image quality based on error statistic and the evaluation method of based on peak signal noise ratio are analysed. In addition, the advantages and disadvantages of these methods are analysed. Moreover, the infrared disturbing images of the experiment result, in which the thermal infrared imager was interfered by laser, were analysed by using these methods. The results show that the methods can better reflect the jamming effects of the infrared imaging system by laser. Furthermore, there is good consistence between evaluation results by using the methods and the results of subjective visual evaluation. And it also provides well repeatability and convenient quantitative analysis. The feasibility of the methods to evaluate the jamming effect was proved. It has some extent reference value for the studying and developing on electro-optical countermeasures equipments and effectiveness evaluation.

Sunxiuqinia faeciviva sp. nov., a facultatively anaerobic organoheterotroph of the Bacteroidetes isolated from deep subseafloor sediment.

PubMed

Takai, Ken; Abe, Mariko; Miyazaki, Masayuki; Koide, Osamu; Nunoura, Takuro; Imachi, Hiroyuki; Inagaki, Fumio; Kobayashi, Tohru

2013-05-01

A facultatively anaerobic organoheterotroph, designated JAM-BA0302(T), was isolated from a deep subseafloor sediment at a depth of 247.1 m below the seafloor off the Shimokita Peninsula of Japan in the north-western Pacific Ocean (Site C9001 , water depth 1180 m). Cells of strain JAM-BA0302(T) showed gliding motility and were thin, long rods with peritrichous fimbriae-like structures. Growth occurred at 4-37 °C (optimum 30 °C; doubling time 8 h), at pH 5.4-8.3 (optimum pH 7.5) and with 5-60 g NaCl l(-1) (optimum 20-25 g l(-1)). The isolate utilized proteinaceous substrates such as yeast extract, tryptone, casein and Casamino acids with O2 respiration or fermentation. Strain JAM-BA0302(T) was a piezotolerant bacterium that could grow at pressures as high as 25 MPa under aerobic conditions and 10 MPa under anaerobic conditions. The G+C content of the genomic DNA was 43.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain JAM-BA0302(T) was most closely related to yet-undescribed strains recently isolated from various marine sedimentary environments (>99.6 % 16S rRNA gene sequence similarity) and was moderately related to Sunxiuqinia elliptica DQHS-4(T), isolated from a sea cucumber farm sediment (95.5 % 16S rRNA gene sequence similarity) within the Bacteroidetes. The phylogenetic analysis suggested that the isolate should belong to the genus Sunxiuqinia. However, low DNA-DNA relatedness (<11 %) and many physiological and molecular properties differentiated the isolate from those previously describedhttp://dx.doi.org/10.1601/nm.22746. We propose here a novel species of the genus Sunxiuqinia, with the name Sunxiuqinia faeciviva sp. nov. The type strain is JAM-BA0302(T) ( = JCM 15547(T)  = NCIMB 14481(T)).

Jammed systems of oriented needles always percolate on square lattices

NASA Astrophysics Data System (ADS)

Kondrat, Grzegorz; Koza, Zbigniew; Brzeski, Piotr

2017-08-01

Random sequential adsorption (RSA) is a standard method of modeling adsorption of large molecules at the liquid-solid interface. Several studies have recently conjectured that in the RSA of rectangular needles, or k -mers, on a square lattice, percolation is impossible if the needles are sufficiently long (k of order of several thousand). We refute these claims and present rigorous proof that in any jammed configuration of nonoverlapping, fixed-length, horizontal, or vertical needles on a square lattice, all clusters are percolating clusters.

The importance of antipersistence for traffic jams

NASA Astrophysics Data System (ADS)

Krause, Sebastian M.; Habel, Lars; Guhr, Thomas; Schreckenberg, Michael

2017-05-01

Universal characteristics of road networks and traffic patterns can help to forecast and control traffic congestion. The antipersistence of traffic flow time series has been found for many data sets, but its relevance for congestion has been overseen. Based on empirical data from motorways in Germany, we study how antipersistence of traffic flow time-series impacts the duration of traffic congestion on a wide range of time scales. We find a large number of short-lasting traffic jams, which implies a large risk for rear-end collisions.

Jammed-array wideband sawtooth filter.

PubMed

Tan, Zhongwei; Wang, Chao; Goda, Keisuke; Malik, Omer; Jalali, Bahram

2011-11-21

We present an all-optical passive low-cost spectral filter that exhibits a high-resolution periodic sawtooth spectral pattern without the need for active optoelectronic components. The principle of the filter is the partial masking of a phased array of virtual light sources with multiply jammed diffraction orders. We utilize the filter's periodic linear map between frequency and intensity to demonstrate fast sensitive interrogation of fiber Bragg grating sensor arrays and ultrahigh-frequency electrical sawtooth waveform generation. © 2011 Optical Society of America

KSC-2012-1552

NASA Image and Video Library

2012-02-23

ORLANDO, Fla. -- At NASA's exhibit inside the Orange County Convention Center in Orlando, Fla., visitors to the NBA All-Star Jam Session participate in hands-on educational activities to learn more about how science plays into sports. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

Experimental investigation of granular dynamics close to the jamming transition

NASA Astrophysics Data System (ADS)

Caballero, G.; Kolb, E.; Lindner, A.; Lanuza, J.; Clément, E.

2005-06-01

We present different experiments on dense granular assemblies with the aim of clarifying the notion of 'jamming transition' for these assemblies of non-Brownian particles. The experimental set-ups differ in the way in which external perturbations are applied in order to unjam the systems. The first experiment monitors the response to a locally applied deformation of a model packing at rest. The two other experiments study local and collective dynamics in a granular assembly weakly excited by vibration.

Peering into the Future: Peer-to-Peer Technology as a Model for Distributed Joint Battlespace Intelligence Dissemination and Operational Tasking

DTIC Science & Technology

2001-06-01

redundant topology.ൺ For example, assume that a user is looking for a recipe for strawberry rhubarb pie. Once connected to the network, the user asks...relatively quick and thorough. (See Figure 6). 73 John Borland, "Democracy’s Traffic Jams ," CNET...Traffic Jams ." CNET News.Com. 26 October 2000. n.p. On-line, Internet. Available from http://news.cnet.com/news/0-1005-201-3248711-2.html. Clip2

Multi-fingered haptic palpation utilizing granular jamming stiffness feedback actuators

NASA Astrophysics Data System (ADS)

Li, Min; Ranzani, Tommaso; Sareh, Sina; Seneviratne, Lakmal D.; Dasgupta, Prokar; Wurdemann, Helge A.; Althoefer, Kaspar

2014-09-01

This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators for simulating tissue palpation procedures in traditional and in robot-assisted minimally invasive surgery. Soft tissue stiffness is simulated by changing the stiffness property of the actuator during palpation. For the first time, granular jamming and pneumatic air actuation are combined to realize stiffness modulation. The stiffness feedback actuator is validated by stiffness measurements in indentation tests and through stiffness discrimination based on a user study. According to the indentation test results, the introduction of a pneumatic chamber to granular jamming can amplify the stiffness variation range and reduce hysteresis of the actuator. The advantage of multi-fingered palpation using the proposed actuators is proven by the comparison of the results of the stiffness discrimination performance using two-fingered (sensitivity: 82.2%, specificity: 88.9%, positive predicative value: 80.0%, accuracy: 85.4%, time: 4.84 s) and single-fingered (sensitivity: 76.4%, specificity: 85.7%, positive predicative value: 75.3%, accuracy: 81.8%, time: 7.48 s) stiffness feedback.

Modeling mobile source emissions during traffic jams in a micro urban environment.

PubMed

Kondrashov, Valery V; Reshetin, Vladimir P; Regens, James L; Gunter, James T

2002-01-01

Urbanization typically involves a continuous increase in motor vehicle use, resulting in congestion known as traffic jams. Idling emissions due to traffic jams combine with the complex terrain created by buildings to concentrate atmospheric pollutants in localized areas. This research simulates emissions concentrations and distributions for a congested street in Minsk, Belarus. Ground-level (up to 50-meters above the street's surface) pollutant concentrations were calculated using STAR (version 3.10) with emission factors obtained from the U.S. Environmental Protection Agency, wind speed and direction, and building location and size. Relative emissions concentrations and distributions were simulated at 1-meter and 10-meters above street level. The findings demonstrate the importance of wind speed and direction, and building size and location on emissions concentrations and distributions, with the leeward sides of buildings retaining up to 99 percent of the emitted pollutants within 1-meter of street level, and up to 77 percent 10-meters above the street.

Improvement of low energy atmospheric neutrino flux calculation using the JAM nuclear interaction model

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

Honda, M.; Kajita, T.; Kasahara, K.

We present the calculation of the atmospheric neutrino fluxes with an interaction model named JAM, which is used in PHITS (Particle and Heavy-Ion Transport code System) [K. Niita et al., Radiation Measurements 41, 1080 (2006).]. The JAM interaction model agrees with the HARP experiment [H. Collaboration, Astropart. Phys. 30, 124 (2008).] a little better than DPMJET-III[S. Roesler, R. Engel, and J. Ranft, arXiv:hep-ph/0012252.]. After some modifications, it reproduces the muon flux below 1 GeV/c at balloon altitudes better than the modified DPMJET-III, which we used for the calculation of atmospheric neutrino flux in previous works [T. Sanuki, M. Honda, T.more » Kajita, K. Kasahara, and S. Midorikawa, Phys. Rev. D 75, 043005 (2007).][M. Honda, T. Kajita, K. Kasahara, S. Midorikawa, and T. Sanuki, Phys. Rev. D 75, 043006 (2007).]. Some improvements in the calculation of atmospheric neutrino flux are also reported.« less

Non-Gaussian behavior in jamming / unjamming transition in dense granular materials

NASA Astrophysics Data System (ADS)

Atman, A. P. F.; Kolb, E.; Combe, G.; Paiva, H. A.; Martins, G. H. B.

2013-06-01

Experiments of penetration of a cylindrical intruder inside a bidimensional dense and disordered granular media were reported recently showing the jamming / unjamming transition. In the present work, we perform molecular dynamics simulations with the same geometry in order to assess both kinematic and static features of jamming / unjamming transition. We study the statistics of the particles velocities at the neighborhood of the intruder to evince that both experiments and simulations present the same qualitative behavior. We observe that the probability density functions (PDF) of velocities deviate from Gaussian depending on the packing fraction of the granular assembly. In order to quantify these deviations we consider a q-Gaussian (Tsallis) function to fit the PDF's. The q-value can be an indication of the presence of long range correlations along the system. We compare the fitted PDF's obtained with those obtained using the stretched exponential, and sketch some conclusions concerning the nature of the correlations along a granular confined flow.

Elastic properties of compressed emulsions

NASA Astrophysics Data System (ADS)

Jorjadze, Ivane; Brujic, Jasna

2012-02-01

Visualizing the packing of a dense emulsion in 3D as a function of the external pressure allows us to characterize the geometry and the local stress distribution inside this jammed system. We first test the scaling laws of the pressure and average coordination number over two orders of magnitude in density. We find deviations from theoretical exponents due to the non-affine motion of the particles. Second, we observe that the distribution of forces changes from a broad exponential at the jamming point to a narrower Gaussian-like distribution under high compression. Finally, we calculate the density of states from the measured force network in the approximation of a harmonic potential. Close to jamming, the number of low frequency modes is high, while the application of pressure shifts the distribution to higher frequencies, indicative of a rigid network. The confocal images reveal the structural features associated with the low frequency modes, as well as their localization within the packing. These data are then compared with published results from numerical simulations.

Optimization of a matched-filter receiver for frequency hopping code acquisition in jamming

NASA Astrophysics Data System (ADS)

Pawlowski, P. R.; Polydoros, A.

A matched-filter receiver for frequency hopping (FH) code acquisition is optimized when either partial-band tone jamming or partial-band Gaussian noise jamming is present. The receiver is matched to a segment of the FH code sequence, sums hard per-channel decisions to form a test, and uses multiple tests to verify acquisition. The length of the matched filter and the number of verification tests are fixed. Optimization is then choosing thresholds to maximize performance based upon the receiver's degree of knowledge about the jammer ('side-information'). Four levels of side-information are considered, ranging from none to complete. The latter level results in a constant-false-alarm-rate (CFAR) design. At each level, performance sensitivity to threshold choice is analyzed. Robust thresholds are chosen to maximize performance as the jammer varies its power distribution, resulting in simple design rules which aid threshold selection. Performance results, which show that optimum distributions for the jammer power over the total FH bandwidth exist, are presented.

Jamming Attack in Wireless Sensor Network: From Time to Space

NASA Astrophysics Data System (ADS)

Sun, Yanqiang; Wang, Xiaodong; Zhou, Xingming

Classical jamming attack models in the time domain have been proposed, such as constant jammer, random jammer, and reactive jammer. In this letter, we consider a new problem: given k jammers, how does the attacker minimize the pair-wise connectivity among the nodes in a Wireless Sensor Network (WSN)? We call this problem k-Jammer Deployment Problem (k-JDP). To the best of our knowledge, this is the first attempt at considering the position-critical jamming attack against wireless sensor network. We mainly make three contributions. First, we prove that the decision version of k-JDP is NP-complete even in the ideal situation where the attacker has full knowledge of the topology information of sensor network. Second, we propose a mathematical formulation based on Integer Programming (IP) model which yields an optimal solution. Third, we present a heuristic algorithm HAJDP, and compare it with the IP model. Numerical results show that our heuristic algorithm is computationally efficient.

Deterministic Reconfigurable Control Design for the X-33 Vehicle

NASA Technical Reports Server (NTRS)

Wagner, Elaine A.; Burken, John J.; Hanson, Curtis E.; Wohletz, Jerry M.

1998-01-01

In the event of a control surface failure, the purpose of a reconfigurable control system is to redistribute the control effort among the remaining working surfaces such that satisfactory stability and performance are retained. Four reconfigurable control design methods were investigated for the X-33 vehicle: Redistributed Pseudo-Inverse, General Constrained Optimization, Automated Failure Dependent Gain Schedule, and an Off-line Nonlinear General Constrained Optimization. The Off-line Nonlinear General Constrained Optimization approach was chosen for implementation on the X-33. Two example failures are shown, a right outboard elevon jam at 25 deg. at a Mach 3 entry condition, and a left rudder jam at 30 degrees. Note however, that reconfigurable control laws have been designed for the entire flight envelope. Comparisons between responses with the nominal controller and reconfigurable controllers show the benefits of reconfiguration. Single jam aerosurface failures were considered, and failure detection and identification is considered accomplished in the actuator controller. The X-33 flight control system will incorporate reconfigurable flight control in the baseline system.

Relationship between microscopic dynamics in traffic flow and complexity in networks.

PubMed

Li, Xin-Gang; Gao, Zi-You; Li, Ke-Ping; Zhao, Xiao-Mei

2007-07-01

Complex networks are constructed in the evolution process of traffic flow, and the states of traffic flow are represented by nodes in the network. The traffic dynamics can then be studied by investigating the statistical properties of those networks. According to Kerner's three-phase theory, there are two different phases in congested traffic, synchronized flow and wide moving jam. In the framework of this theory, we study different properties of synchronized flow and moving jam in relation to complex network. Scale-free network is constructed in stop-and-go traffic, i.e., a sequence of moving jams [Chin. Phys. Lett. 10, 2711 (2005)]. In this work, the networks generated in synchronized flow are investigated in detail. Simulation results show that the degree distribution of the networks constructed in synchronized flow has two power law regions, so the distinction in topological structure can really reflect the different dynamics in traffic flow. Furthermore, the real traffic data are investigated by this method, and the results are consistent with the simulations.

Combination of different antifungal agents in oil-in-water emulsions to control strawberry jam spoilage.

PubMed

Ribes, Susana; Fuentes, Ana; Talens, Pau; Barat, Jose Manuel

2018-01-15

The combination of antifungal agents (cinnamon bark oil, zinc gluconate and trans-ferulic acid) in oil-in-water emulsions to control the fungal spoilage of strawberry jams, minimising essential oil's sensory impact, was evaluated in this work. The in vitro assays of free antifungal agents were performed against five fungal strains; meanwhile, the emulsions assays were conducted against Aspergillus niger given its strong resistance and its relevance in strawberry products. The emulsion formulated with 0.08mg/g of essential oil was able to inhibit mould growth after the incubation period. The incorporation of zinc gluconate or trans-ferulic acid, independently of the concentration used, allowed to reduce a 25% the amount of essential oil needed to inhibit the microbial growth. The combination of antifungal agents in the emulsions has demonstrated to be an effective alternative to reduce the amount of essential oil employed, maintaining the hygienic quality and sensory profile of the strawberry jam. Copyright © 2017 Elsevier Ltd. All rights reserved.

Jamming/flowing transition of non-Brownian particles suspended in a iso-density fluid flowing in a 2D rectangular duct

NASA Astrophysics Data System (ADS)

Burel, Maxym; Martin, Sylvain; Bonnefoy, Olivier

2017-06-01

We present the results of an experimental study on the jamming/flowing transition. A suspension of neutrally buoyant large particles flows in an horizontal rectangular duct, where an artificial restriction triggers jamming. We show that the avalanche distribution size is exponential, that is memoryless. We further demonstrate that the avalanche size diverges when the restriction size approaches a critical value and that this divergence is well described by a power law. The parameters (critical opening size and divergence velocity) are compared to literature values and show a strong similarity with others systems. Another result of this paper is the study of the influence of the particle morphology. We show that, for a moderate restriction size, the dead-zone formed right upstream of the restriction is larger for angular particles but, paradoxically, that the avalanche size is larger for polyhedra compared to spheres by at least one order of magnitude.

SDSS-IV MaNGA: Variation of the Stellar Initial Mass Function in Spiral and Early-type Galaxies

NASA Astrophysics Data System (ADS)

Li, Hongyu; Ge, Junqiang; Mao, Shude; Cappellari, Michele; Long, R. J.; Li, Ran; Emsellem, Eric; Dutton, Aaron A.; Li, Cheng; Bundy, Kevin; Thomas, Daniel; Drory, Niv; Lopes, Alexandre Roman

2017-04-01

We perform Jeans anisotropic modeling (JAM) on elliptical and spiral galaxies from the MaNGA DR13 sample. By comparing the stellar mass-to-light ratios estimated from stellar population synthesis and from JAM, we find a systematic variation of the initial mass function (IMF) similar to that in the earlier {{ATLAS}}3{{D}} results. Early-type galaxies (elliptical and lenticular) with lower velocity dispersions within one effective radius are consistent with a Chabrier-like IMF, while galaxies with higher velocity dispersions are consistent with a more bottom-heavy IMF such as the Salpeter IMF. Spiral galaxies have similar systematic IMF variations, but with slightly different slopes and larger scatters, due to the uncertainties caused by the higher gas fractions and extinctions for these galaxies. Furthermore, we examine the effects of stellar mass-to-light ratio gradients on our JAM modeling, and we find that the trends become stronger after considering the gradients.

Order and disorder in traffic and self-driven many-particle systems

NASA Astrophysics Data System (ADS)

Helbing, Dirk

2002-07-01

During the last decade, physicists have identified various spatio-temporal patterns of motion in vehicle and pedestrian traffic. Moreover, by applying and extending methods from statistical physics and non-linear dynamics, these have been successfully explained by means of self-driven many-particle models. Some of the questions now understood are the following: Why are vehicles sometimes stopped by so-called "phantom traffic jams," although they all like to drive fast? What are the mechanisms behind stop-and-go traffic? Why are there several different kinds of congestion, and how are they related? Why do most traffic jams occur considerably before the road capacity is reached? Can a temporary reduction of the traffic volume cause a lasting traffic jam? What is the origin of fluctuations in traffic systems and which consequences do they have? Why do pedestrians moving in opposite directions normally organize in lanes, while nervous crowds are "freezing by heating?" Why do panicking pedestrians produce dangerous deadlocks?

Application of ELJ to create and maintain side channels in a dynamic gravel bed river

NASA Astrophysics Data System (ADS)

Crabbe, E.; Crowe Curran, J.; Ockelford, A.

2017-12-01

Braided and anastomosing rivers create and maintain a large amount of side channel habitat. Unfortunately, many rivers that were once multi-channel rivers have been constrained to single thread channels as a consequence of land use changes that occurred in the 19th and 20th centuries or earlier. An increasingly common management goal today is the re-creation of self-maintaining side and tributary habitat through as natural means as possible. This work examines the geomorphic history of one such channel and the success of recent rehabilitation efforts. Our case study comes from the South Fork Nooksack River in the Cascades Range in Washington State. The Nooksack River is a gravel and sand bed channel with a snowmelt dominated hydrograph. Engineered log jams (ELJ) have been employed to direct flow into side and chute channels with the larger goals of increasing overall channel complexity and salmon spawning opportunities. ELJs have been constructed on the channel since the 2000s, and the ELJs in the study reaches range in age up to 10 years. The size and design of individual jams within the reach vary, enabling a comparison between jam types. ELJs are evaluated for their ability to maintain gravel bar locations and open tributary channels through the snowmelt season over the reach scale. Additional goals of trapping wood onto the jams and existing bars, stabilizing channel banks, and allowing for the growth of bar vegetation are also examined.

Linkage Of A Finite Element Flow Model With A Soil Moisture Model: Challanges Under Semiarid Conditions

NASA Astrophysics Data System (ADS)

Roediger, T.; Siebert, C.; Krause, P.

2008-12-01

The arid to semiarid Middle East is a region of extreme growth of population. Hence, the rare and over- expoitated water resources in that region have to be more protected against antropogenic and geogenic pollution. One way to help solving that complex issue is to develop an intelligent and integrated strategy to manage all available water resources, which is the aim of the multilateral SMART-project in the Lower Jordan Valley. To generate such an IWRM, all water resources (groundwater, surface runoff, waste water) of the valley and its shoulders have to be quanti- and qualitatively evaluated. The strategy of SMART is to upscale knowledge, extracted from local catchment areas to the project scale, which covers the area between Sea of Galilee, Jerusalem, Dead Sea and Amman. The study areas of the here presented sub-project are the Wadis Qilt (Palestine) and Al Arab (Jordan). The aim of the sub-project is to evaluate natural resources on catchment scale by combining hydrochemical and hydraulical methods to develop a high precision model. Concerning the quantification of the system, two seperated models will be linked: a numerical finite element flow-model for the groundwater passage and a new devolped hydrological model JAMS, which is excellently prepared for humid conditions. The power of JAMS is the highly accurate assessment of soil moisture balance and consequently of surface runoff and groundwater recharge. However, the empirical equations and input parameters have to be adjusted onto the conditions of the semiarid Wadi Al Arab and the arid Wadi Qilt. After the adaption of JAMS, the spatially and temporarily differentiated calculation of runoff and groundwater recharge is possible. Beside climatic gradients, the key issue is, to correctly evaluate the evapotranspiration in respect to the different classes of landuse. In the study area Wadi Al Arab, the groundwater recharge was calculated as area-indicated output parameter of JAMS. This output was used to be the spatial differentiated input parameter of the numerical flow model. The advantage is the direct comparability of the finite-element meshs of JAMS and FeFlow. However, the individual definitions of values (recharge, base flow, exfiltration of JAMS, infiltration of FeFlow, etc.) of both models have to be linked by an interface between both systems. One of the biggest challenges is the temporal discretization of recharge between leaving soilcrust and entering groundwater table. In fact, the target was to evaluate the effects of retardation of the unsaturated zone in dependence to the hydraulic parameters of the entire groundwater reservoir.

Design of two-DMD based zoom MW and LW dual-band IRSP using pixel fusion

NASA Astrophysics Data System (ADS)

Pan, Yue; Xu, Xiping; Qiao, Yang

2018-06-01

In order to test the anti-jamming ability of mid-wave infrared (MWIR) and long-wave infrared (LWIR) dual-band imaging system, a zoom mid-wave (MW) and long-wave (LW) dual-band infrared scene projector (IRSP) based on two-digital micro-mirror device (DMD) was designed by using a projection method of pixel fusion. Two illumination systems, which illuminate the two DMDs directly with Kohler telecentric beam respectively, were combined with projection system by a spatial layout way. The distances of projection entrance pupil and illumination exit pupil were also analyzed separately. MWIR and LWIR virtual scenes were generated respectively by two DMDs and fused by a dichroic beam combiner (DBC), resulting in two radiation distributions in projected image. The optical performance of each component was evaluated by ray tracing simulations. Apparent temperature and image contrast were demonstrated by imaging experiments. On the basis of test and simulation results, the aberrations of optical system were well corrected, and the quality of projected image meets test requirements.

A Unified Multi-Functional Dynamic Spectrum Access Framework: Tutorial, Theory and Multi-GHz Wideband Testbed

PubMed Central

Qiu, Robert; Guo, Nan; Li, Husheng; Wu, Zhiqiang; Chakravarthy, Vasu; Song, Yu; Hu, Zhen; Zhang, Peng; Chen, Zhe

2009-01-01

Dynamic spectrum access is a must-have ingredient for future sensors that are ideally cognitive. The goal of this paper is a tutorial treatment of wideband cognitive radio and radar—a convergence of (1) algorithms survey, (2) hardware platforms survey, (3) challenges for multi-function (radar/communications) multi-GHz front end, (4) compressed sensing for multi-GHz waveforms—revolutionary A/D, (5) machine learning for cognitive radio/radar, (6) quickest detection, and (7) overlay/underlay cognitive radio waveforms. One focus of this paper is to address the multi-GHz front end, which is the challenge for the next-generation cognitive sensors. The unifying theme of this paper is to spell out the convergence for cognitive radio, radar, and anti-jamming. Moore’s law drives the system functions into digital parts. From a system viewpoint, this paper gives the first comprehensive treatment for the functions and the challenges of this multi-function (wideband) system. This paper brings together the inter-disciplinary knowledge. PMID:22454598

On Performance Analysis of Protective Jamming Schemes in Wireless Sensor Networks.

PubMed

Li, Xuran; Dai, Hong-Ning; Wang, Hao; Xiao, Hong

2016-11-24

Wireless sensor networks (WSNs) play an important role in Cyber Physical Social Sensing (CPSS) systems. An eavesdropping attack is one of the most serious threats to WSNs since it is a prerequisite for other malicious attacks. In this paper, we propose a novel anti-eavesdropping mechanism by introducing friendly jammers to wireless sensor networks (WSNs). In particular, we establish a theoretical framework to evaluate the eavesdropping risk of WSNs with friendly jammers and that of WSNs without jammers. Our theoretical model takes into account various channel conditions such as the path loss and Rayleigh fading, the placement schemes of jammers and the power controlling schemes of jammers. Extensive results show that using jammers in WSNs can effectively reduce the eavesdropping risk. Besides, our results also show that the appropriate placement of jammers and the proper assignment of emitting power of jammers can not only mitigate the eavesdropping risk but also may have no significant impairment to the legitimate communications.

[Purification of complicated industrial organic waste gas by complex absorption].

PubMed

Chen, Ding-Sheng; Cen, Chao-Ping; Tang, Zhi-Xiong; Fang, Ping; Chen, Zhi-Hang

2011-12-01

Complicated industrial organic waste gas with the characteristics of low concentration,high wind volume containing inorganic dust and oil was employed the research object by complex absorption. Complex absorption mechanism, process flow, purification equipment and engineering application were studied. Three different surfactants were prepared for the composite absorbent to purify exhaust gas loaded with toluene and butyl acetate, respectively. Results show that the low surface tension of the composite absorbent can improve the removal efficiency of toluene and butyl acetate. With the advantages of the water film, swirl plate and fill absorption device, efficient absorption equipment was developed for the treatment of complicated industrial organic waste gas. It is with superiorities of simple structure, small size, anti-jam and high mass transfer. Based on absorption technology, waste gas treatment process integrated with heating stripping, burning and anaerobic and other processes, so that emissions of waste gas and absorption solution could meet the discharge standards. The technology has been put into practice, such as manufacturing and spraying enterprises.

Selective wave-transmitting electromagnetic absorber through composite metasurface

NASA Astrophysics Data System (ADS)

Sun, Zhiwei; Zhao, Junming; Zhu, Bo; Jiang, Tian; Feng, Yijun

2017-11-01

Selective wave-transmitting absorbers which have one or more narrow transmission bands inside a wide absorption band are often demanded in wireless communication and radome applications for reducing the coupling between different systems, improving anti-jamming capability, and reducing antennas' radar cross section. Here we propose a feasible method that utilizing composite of two metasurfaces with different polarization dependent characteristics, one works as electromagnetic polarization rotator and the other as a wideband polarization dependent electromagnetic wave absorber. The polarization rotator produces a cross polarization output in the wave-transmitting band, while preserves the polarization of the incidence outside the band. The metasurface absorber works for certain linear polarization with a much wider absorption band covering the wave-transmitting frequency. When combining these two metasurfaces properly, the whole structure behaves as a wideband absorber with a certain frequency transmission window. The proposal may be applied in radome designs to reduce the radar cross section of antenna or improving the electromagnetic compatibility in communication devices.

On Performance Analysis of Protective Jamming Schemes in Wireless Sensor Networks

PubMed Central

Li, Xuran; Dai, Hong-Ning; Wang, Hao; Xiao, Hong

2016-01-01

Wireless sensor networks (WSNs) play an important role in Cyber Physical Social Sensing (CPSS) systems. An eavesdropping attack is one of the most serious threats to WSNs since it is a prerequisite for other malicious attacks. In this paper, we propose a novel anti-eavesdropping mechanism by introducing friendly jammers to wireless sensor networks (WSNs). In particular, we establish a theoretical framework to evaluate the eavesdropping risk of WSNs with friendly jammers and that of WSNs without jammers. Our theoretical model takes into account various channel conditions such as the path loss and Rayleigh fading, the placement schemes of jammers and the power controlling schemes of jammers. Extensive results show that using jammers in WSNs can effectively reduce the eavesdropping risk. Besides, our results also show that the appropriate placement of jammers and the proper assignment of emitting power of jammers can not only mitigate the eavesdropping risk but also may have no significant impairment to the legitimate communications. PMID:27886154

A model for simulating the grinding and classification cyclic system of waste PCBs recycling production line.

PubMed

Yang, Deming; Xu, Zhenming

2011-09-15

Crushing and separating technology is widely used in waste printed circuit boards (PCBs) recycling process. A set of automatic line without negative impact to environment for recycling waste PCBs was applied in industry scale. Crushed waste PCBs particles grinding and classification cyclic system is the most important part of the automatic production line, and it decides the efficiency of the whole production line. In this paper, a model for computing the process of the system was established, and matrix analysis method was adopted. The result showed that good agreement can be achieved between the simulation model and the actual production line, and the system is anti-jamming. This model possibly provides a basis for the automatic process control of waste PCBs production line. With this model, many engineering problems can be reduced, such as metals and nonmetals insufficient dissociation, particles over-pulverizing, incomplete comminuting, material plugging and equipment fever. Copyright © 2011 Elsevier B.V. All rights reserved.

Adaptively combined FIR and functional link artificial neural network equalizer for nonlinear communication channel.

PubMed

Zhao, Haiquan; Zhang, Jiashu

2009-04-01

This paper proposes a novel computational efficient adaptive nonlinear equalizer based on combination of finite impulse response (FIR) filter and functional link artificial neural network (CFFLANN) to compensate linear and nonlinear distortions in nonlinear communication channel. This convex nonlinear combination results in improving the speed while retaining the lower steady-state error. In addition, since the CFFLANN needs not the hidden layers, which exist in conventional neural-network-based equalizers, it exhibits a simpler structure than the traditional neural networks (NNs) and can require less computational burden during the training mode. Moreover, appropriate adaptation algorithm for the proposed equalizer is derived by the modified least mean square (MLMS). Results obtained from the simulations clearly show that the proposed equalizer using the MLMS algorithm can availably eliminate various intensity linear and nonlinear distortions, and be provided with better anti-jamming performance. Furthermore, comparisons of the mean squared error (MSE), the bit error rate (BER), and the effect of eigenvalue ratio (EVR) of input correlation matrix are presented.

Fruits of Black Chokeberry Aronia melanocarpa in the Prevention of Chronic Diseases.

PubMed

Jurikova, Tunde; Mlcek, Jiri; Skrovankova, Sona; Sumczynski, Daniela; Sochor, Jiri; Hlavacova, Irena; Snopek, Lukas; Orsavova, Jana

2017-06-07

In recent years, growing attention has been focused on the utilization of natural sources of antioxidants in the prevention of chronic diseases. Black chokeberry ( Aronia melanocarpa ) represents a lesser known fruit species utilized mainly as juices, purees, jams, jellies and wine, as important food colorants or nutritional supplements. The fruit is valued as a great source of antioxidants, especially polyphenols, such as phenolic acids (neochlorogenic and chlorogenic acids) and flavonoids (anthocyanins, proanthocyanidins, flavanols and flavonols), particularly cyanidin-3-galactoside and cyanidin-3-arabinoside, as well as (-)-epicatechin units. The berries of A. melanocarpa , due to the presence and the high content of these bioactive components, exhibit a wide range of positive effects, such as strong antioxidant activity and potential medicinal and therapeutic benefits (gastroprotective, hepatoprotective, antiproliferative or anti-inflammatory activities). They could be also contributory toward the prevention of chronic diseases including metabolic disorders, diabetes and cardiovascular diseases, because of supportive impacts on lipid profiles, fasting plasma glucose and blood pressure levels.

Investigation of the Influence of Air Defense Artillery on Combat Pilot Suppression and Attrition Management Practices

DTIC Science & Technology

1992-05-01

low as possible for better accuracy." (Mamyer, 1979, p. 280) "With the advent of the jamming pod, F-105D flights could once again penetrate at medium...or pumpkins coming at the aircraft." (Fulbrook, 1986a, pp. 43-44) "Generally, there are two types of aviators when bullets start flying. All of us... jamming ; ECM and flare equipment onboard * Importance of targets (both to cummand and control and to pilot) and necessity of achieving target damage

Gain and loss of esteem, direct reciprocity and Heider balance

NASA Astrophysics Data System (ADS)

Hassanibesheli, Forough; Hedayatifar, Leila; Gawroński, Przemysław; Stojkow, Maria; Żuchowska-Skiba, Dorota; Kułakowski, Krzysztof

2017-02-01

The effect of gain and loss of esteem is introduced into the equations of time evolution of social relations, hostile or friendly, in a group of actors. The equations allow for asymmetric relations. We prove that in the presence of this asymmetry, the majority of stable solutions are jammed states, i.e. the Heider balance is not attained there. A phase diagram is constructed with three phases: the jammed phase, the balanced phase with two mutually hostile groups, and the phase of so-called paradise, where all relations are friendly.

The naming (and misnaming) of America

USGS Publications Warehouse

Wexler, Mark

1979-01-01

Jim Jam Ridge winds for several hundred feet a long a spectacular section of the High Sierra, near the heart of northern California's Mother Lode country. According to local historians, its name dates back to a night in the late 1800s when a drunk prospector rolled into a campfire, exploding a handful of rifle shells in his pocket. The fatal incident left his two partners with a severe case of the "jim jams" a common term in those days for the "shakes" and that's how the name took hold.

Nanoporous Polymeric Grating-Based Optical Biosensors (Preprint)

DTIC Science & Technology

2007-03-01

Tombelli, S.; Mascini, M.; Bilia, A; Bergonzi, M. C.; Vincieri, F. F. Talanta 2005, 65, 578-585. Haughey, S. A; Baxter, G. A J of AOAC Inter. 2006 , 89, 862...C.; Bowers, M. T. JAm. Chem. Soc 2006 , 128,8484-8492. (6) Wang, l et. al. Anal. Chim. Acta 1997, 347, 1-8. Jena, B. K.; Raj, C. R. Anal. Chem. 2006 ...78, 6332-6339. Hansen, J. A; Wang, l; Kawde, A; Xiang, Y.; Gothelf, K. V.; Collins, G JAm. Chem. Soc 2006 , 128,2228-2229. Huang, T; 14 Liu, M.; Knight

Fiches pratiques: Nouvelles histoires de modes; Pour se faire une tartine; Le Texte litteraire: "Decouverte" de Guy de Maupassant; Un Regiment dans un nuage (Practical Ideas: New Approaches to Grammatical Mood; How to Make Oneself Bread and Jam; The Literary Text: "Discovered" by Guy de Maupassant; A Regiment in a Cloud).

ERIC Educational Resources Information Center

Saraceni, Luisa; And Others

1993-01-01

Four activities are offered for French second-language classroom use: an exercise to aid comprehension of indicative and subjunctive mood; a lesson in making bread and jam, designed for young children; a study of narration within a novel, using a Guy de Maupassant story; and an exercise in discourse analysis. (MSE)

Coherent detection of frequency-hopped quadrature modulations in the presence of jamming. I - QPSK and QASK modulations

NASA Technical Reports Server (NTRS)

Simon, M. K.; Polydoros, A.

1981-01-01

This paper examines the performance of coherent QPSK and QASK systems combined with FH or FH/PN spread spectrum techniques in the presence of partial-band multitone or noise jamming. The worst-case jammer and worst-case performance are determined as functions of the signal-to-background noise ratio (SNR) and signal-to-jammer power ratio (SJR). Asymptotic results for high SNR are shown to have a linear dependence between the jammer's optimal power allocation and the system error probability performance.

Stabilizing liquid drops of arbitrary shape by the interfacial jamming of nanoparticles

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

Russell, Thomas P.; Cui, Mengmeng; Emrick, Todd

A stabilized assembly including a first liquid phase of non-spherical droplets in a second liquid phase, wherein the second liquid phase is immiscible with the first phase, and nanoparticle surfactants assembled at an interface of the non-spherical droplets and the second phase is disclosed. The nanoparticle surfactants include nanoparticles and end-functionalized polymers that can interact through ligand type interactions, and the first phase is stabilized by a disordered, jammed layer of nanoparticle surfactants. A method of preparing a stabilized assembly is also disclosed.

Laser pulse coded signal frequency measuring device based on DSP and CPLD

NASA Astrophysics Data System (ADS)

Zhang, Hai-bo; Cao, Li-hua; Geng, Ai-hui; Li, Yan; Guo, Ru-hai; Wang, Ting-feng

2011-06-01

Laser pulse code is an anti-jamming measures used in semi-active laser guided weapons. On account of the laser-guided signals adopting pulse coding mode and the weak signal processing, it need complex calculations in the frequency measurement process according to the laser pulse code signal time correlation to meet the request in optoelectronic countermeasures in semi-active laser guided weapons. To ensure accurately completing frequency measurement in a short time, it needed to carry out self-related process with the pulse arrival time series composed of pulse arrival time, calculate the signal repetition period, and then identify the letter type to achieve signal decoding from determining the time value, number and rank number in a signal cycle by Using CPLD and DSP for signal processing chip, designing a laser-guided signal frequency measurement in the pulse frequency measurement device, improving the signal processing capability through the appropriate software algorithms. In this article, we introduced the principle of frequency measurement of the device, described the hardware components of the device, the system works and software, analyzed the impact of some system factors on the accuracy of the measurement. The experimental results indicated that this system improve the accuracy of the measurement under the premise of volume, real-time, anti-interference, low power of the laser pulse frequency measuring device. The practicality of the design, reliability has been demonstrated from the experimental point of view.

Sodium selenite ameliorates both intestinal and extra-intestinal changes in acetic acid-induced colitis in rats.

PubMed

Soliman, Samar M; Wadie, Walaa; Shouman, Samia A; Ainshoka, Afaf A

2018-06-01

Selenium and its derivatives including sodium selenite (sod sel) belong to the group of essential trace elements needed for proper health and nutrition. They are fairly safe and possess antioxidant and anti-inflammatory properties. The aim of present investigation was to elucidate the effect of sod sel on experimental colitis model in rats. Colitis was induced by intrarectal instillation of 4% (v/v) acetic acid. Two hours later, sod sel was given to rats on a daily basis for 15 consecutive days. Clinical symptoms, colon mass index, spleen weight inflammatory markers, hematological, biochemical, macroscopic, and histological changes were determined. Sod sel markedly ameliorated colitis as evidenced by a significant decrease in macroscopic and microscopic score, disease activity index, colon mass index, and spleen weight. Treatment with sod sel attenuated oxidative stress in the colon by normalizing the colonic content of nitric oxide, malondialdehyde, and reduced glutathione, as well as the activities of catalase, superoxide dismutase, and junctional adhesion molecule (JAM-a). In addition, it significantly reduced colonic myeloperoxidase content, the intercellular adhesion molecule (ICAM-1), and the proinflammatory cytokines; TNF-α, IL-1β. Moreover, sod sel normalized hematological parameters, serum transaminases, and kidney and liver function enzymes. The current study indicates that sod sel was effective in ameliorating the intestinal and extra-intestinal manifestation in acetic acid-induced colitis through its antioxidant, anti-inflammatory, and immunomodulatory effects.

Abalone visceral extract inhibit tumor growth and metastasis by modulating Cox-2 levels and CD8+ T cell activity.

PubMed

Lee, Choong-Gu; Kwon, Ho-Keun; Ryu, Jae Ha; Kang, Sung Jin; Im, Chang-Rok; Ii Kim, Jae; Im, Sin-Hyeog

2010-10-20

Abalone has long been used as a valuable food source in East Asian countries. Although the nutritional importance of abalone has been reported through in vitro and in vivo studies, there is little evidence about the potential anti-tumor effects of abalone visceral extract. The aim of the present study is to examine anti-tumor efficacy of abalone visceral extract and to elucidate its working mechanism. In the present study, we used breast cancer model using BALB/c mouse-derived 4T1 mammary carcinoma and investigated the effect of abalone visceral extract on tumor development. Inhibitory effect against tumor metastasis was assessed by histopathology of lungs. Cox-2 productions by primary and secondary tumor were measured by real-time RT-PCR and immunoblotting (IB). Proliferation assay based on [3H]-thymidine incorporation and measurement of cytokines and effector molecules by RT-PCR were used to confirm tumor suppression efficacy of abalone visceral extract by modulating cytolytic CD8+ T cells. The cytotoxicity of CD8+ T cell was compared by JAM test. Oral administration of abalone visceral extract reduced tumor growth (tumor volume and weight) and showed reduced metastasis as confirmed by decreased level of splenomegaly (spleen size and weight) and histological analysis of the lung metastasis (gross analysis and histological staining). Reduced expression of Cox-2 (mRNA and protein) from primary tumor and metastasized lung was also detected. In addition, treatment of abalone visceral extract increased anti-tumor activities of CD8+ T cells by increasing the proliferation capacity and their cytolytic activity. Our results suggest that abalone visceral extract has anti-tumor effects by suppressing tumor growth and lung metastasis through decreasing Cox-2 expression level as well as promoting proliferation and cytolytic function of CD8+ T cells.

Abalone visceral extract inhibit tumor growth and metastasis by modulating Cox-2 levels and CD8+ T cell activity

PubMed Central

2010-01-01

Background Abalone has long been used as a valuable food source in East Asian countries. Although the nutritional importance of abalone has been reported through in vitro and in vivo studies, there is little evidence about the potential anti-tumor effects of abalone visceral extract. The aim of the present study is to examine anti-tumor efficacy of abalone visceral extract and to elucidate its working mechanism. Methods In the present study, we used breast cancer model using BALB/c mouse-derived 4T1 mammary carcinoma and investigated the effect of abalone visceral extract on tumor development. Inhibitory effect against tumor metastasis was assessed by histopathology of lungs. Cox-2 productions by primary and secondary tumor were measured by real-time RT-PCR and immunoblotting (IB). Proliferation assay based on [3H]-thymidine incorporation and measurement of cytokines and effector molecules by RT-PCR were used to confirm tumor suppression efficacy of abalone visceral extract by modulating cytolytic CD8+ T cells. The cytotoxicity of CD8+ T cell was compared by JAM test. Results Oral administration of abalone visceral extract reduced tumor growth (tumor volume and weight) and showed reduced metastasis as confirmed by decreased level of splenomegaly (spleen size and weight) and histological analysis of the lung metastasis (gross analysis and histological staining). Reduced expression of Cox-2 (mRNA and protein) from primary tumor and metastasized lung was also detected. In addition, treatment of abalone visceral extract increased anti-tumor activities of CD8+ T cells by increasing the proliferation capacity and their cytolytic activity. Conclusions Our results suggest that abalone visceral extract has anti-tumor effects by suppressing tumor growth and lung metastasis through decreasing Cox-2 expression level as well as promoting proliferation and cytolytic function of CD8+ T cells. PMID:20961430

The beneficial health aspects of sea buckthorn (Elaeagnus rhamnoides (L.) A.Nelson) oil.

PubMed

Olas, Beata

2018-03-01

Plant oils are known to have biological activity. This review paper summarizes the current knowledge of the composition of sea buckthorn (Elaeagnus rhamnoides (L.) A.Nelson) seed and pulp oil and its beneficial health aspects. In vitro and in vivo studies on humans and animals have found sea buckthorn oil to have a variety of beneficial properties to human health, and indicate that it may be a valuable component of human and animal nutrition. Various bioactive substances are present in all parts of sea buckthorn, and these are used traditionally as raw material for health foods and as nutritional supplements. The oil, berries, leaves and bark have medicinal properties, and the fruits have a unique taste; these parts can be processed to make oil, juice, jam, jellies and candies, as well as alcoholic and non-alcoholic beverages. Sea buckthorn oil may be extracted from the seed or the pulp. The mature seeds contain 8-20% oil and the dried fruit pulp about 20-25%, while the fruit residue contains about 15-20% oil after juice extraction. These oils have high concentrations of lipophilic constituents, most commonly unsaturated fatty acids (UFAs), phytosterols and vitamins A and E. These components have a multifunctional effect on human health, with the fatty acids playing an important function in modifying cerebrovascular and cardiovascular disorders. The oil also has anti-oxidant, anti-inflammatory and anti-depressive properties. Sea buckthorn is a unique plant. Its beneficial properties against cardiovascular disorders have been attributed to its high UFA content and range of phytosterols, especially beta-sitosterol. However, its different action on the human organism remain unclear, and further well-controlled, high-quality experiments with human subjects are required to determine the prophylactic and therapeutic doses of sea buckthorn oil for use in clinical studies. Additional studies are also needed to understand the action by which the oil exerts its beneficial properties, i.e. its cardioprotective and anti-cancer activity. Copyright © 2017 Elsevier B.V. All rights reserved.

Hindered settling and the formation of layered intrusions

NASA Astrophysics Data System (ADS)

Bons, Paul D.; Baur, Albrecht; Elburg, Marlina A.; Lindhuber, Matthias J.; Marks, Michael A. W.; Soesoo, Alvar; van Milligen, Boudewijn P.; Walte, Nicolas P.

2015-04-01

Layered intrusions are characterized by (often repetitive) layering on a range of scales. Many explanations for the formation of such layering have been proposed over the past decades. We investigated the formation of "mats" by hindered crystal settling, a model that was first suggested by Lauder (1964). The interaction of sinking and rising crystals leads to the amplification of perturbations in crystal density within a magma chamber, a process similar to the formation of traffic jams in dense traffic (Bons et al., 2015). Once these "crystal traffic jams" form they constitute a barrier for further settling of crystals. Between these barriers, the magma evolves in a semi-closed system in which stratification may develop by gravitational sorting. Barriers, and therefore layers, form sequentially during inward cooling of the magma chamber. Barring later equilibration, mineralogical and geochemical trends within the layers are repetitive, but with variations due to the random process of initial perturbation formation. Layers can form in the transition between two end-member regimes: (1) in a fast cooling and/or viscous magma crystals cannot sink or float a significant distance and minerals are distributed homogeneously throughout the chamber; (2) in a slow cooling and/or low-viscosity magma crystals can quickly settle at the top and bottom of the chamber and crystals concentrations are never high enough to form "traffic jams". As a result, heavy and light minerals get fully separated in the chamber. Between these two end members, crystals can sink and float a significant distance, but not the whole height of the magma chamber before entrapment in "traffic jams". We illustrate the development of layers with numerical models and compare the results with the layered nepheline syenites (kakortokites) of the Ilímaussaq intrusion in SW Greenland. References: Bons, P.D., Baur, A., Elburg, M.A., Lindhuber, M.J., Marks, M.A.W., Soesoo, A., van Milligen, B.P., Walte, N.P. 2015. Layered intrusions and traffic jams. Geology 43, 71-74 Lauder, W. 1964. Mat formation and crystal settling in magma. Nature 202, 1100-1101.

Air-fluidized grains as a model system: Self-propelling and jamming

NASA Astrophysics Data System (ADS)

Daniels, Lynn J.

This thesis examines two concepts -- self-propelling and jamming -- that have been employed to unify disparate non-equilibrium systems, in the context of a monolayer of grains fluidized by a temporally and spatially homogeneous upflow of air. The first experiment examines the single particle dynamics of air-fluidized rods. For Brownian rods, equipartition of energy holds and rotational motion sets a timescale after which directional memory is lost. Air-fluidized rods no longer obey equipartion; they self-propel, moving preferentially along their long axis. We show that self-propelling can be treated phenomenologically as an enhanced memory effect causing directional memory to persist for times longer than expected for thermal systems. The second experiment studies dense collections of self-propelling air-fluidized rods. We observe collective propagating modes that give rise to anomalously large fluctuations in the local number density. We quantify these compression waves by calculating the dynamic structure factor and show that the wavespeed is weakly linear with increasing density. It has been suggested that the observed behavior might be explained using the framework put forth by Baskaran et al. [12]. The third experiment seeks to determine whether a force analogous to the critical Casimir force in fluids exists for a large sphere fluidized in the presence of a background of smaller spheres. The behavior of such a large sphere is fully characterized showing that, rather than behaving like a sphere driven by turbulence, the large ball self-propels. We also show that the background is responsible for the purely attractive, intermediate-ranged interaction force between two simultaneously-fluidized large balls. The final experiment seeks to determine what parameters control the diverging relaxation timescale associated with the jamming transition. By tilting our apparatus, we quantify pressure, packing fraction, and temperature simultaneously with dynamics as we approach jamming. We obtain an equation of state that agrees well with simulation and free volume theory. We collapse the relaxation time by defining a time- and energy-scale using pressure, consistent with recent simulation [82]. These experiments are further confirmation of the universality of the concepts of self-propelling and jamming.

The role of large wood in retaining fine sediment, organic matter and plant propagules in a small, single-thread forest river

NASA Astrophysics Data System (ADS)

Osei, Nana A.; Gurnell, Angela M.; Harvey, Gemma L.

2015-04-01

This paper investigates associations among large wood accumulations, retained sediment, and organic matter and the establishment of a viable propagule bank within a forested reach of a lowland river, the Highland Water, UK. A wood survey within the 2-km study reach, illustrates that the quantity of wood retained within the channel is typical of relatively unmanaged river channels bordered by deciduous woodland and that the wood accumulations (jams) that are present are well developed, typically spanning the river channel and comprised of wood that is well decayed. Sediment samples were obtained in a stratified random design focusing on nine subreaches within which samples were aggregated from five different types of sampling location. Two of these locations were wood-associated (within and on bank faces immediately adjacent to wood jams), and the other three locations represented the broader river environment (gravel bars, bank faces, floodplain). The samples were analysed to establish their calibre, organic, and viable plant propagule content. The gravel bar sampling locations retained significantly coarser sediment containing a lower proportion of organic matter and viable propagules than the other four sampling locations. The two wood-related sampling locations retained sediment of intermediate calibre between the gravel bar and the bank-floodplain samples but they retained significantly more organic matter and viable propagules than were found in the other three sampling locations. In particular, the jam bank samples (areas of sediment accumulation against bank faces adjacent to wood jams) contained the highest number of propagules and the largest number of propagule species. These results suggest that retention of propagules, organic matter and relatively fine sediment in and around wood jams has the potential to support vegetation regeneration, further sediment retention, and as a consequence, landform development within woodland streams, although this process is arrested by grazing at the study site. These results also suggest that self-restoration using wood is a potentially cost-effective and far-reaching river restoration strategy but that its full effects develop gradually and require the establishment of a functioning wood budget coupled with grazing levels that are in balance with vegetation growth.

Application potential for some sugar substitutes in some low energy and diabetic foods.

PubMed

Bakr, A A

1997-06-01

Preparation of acceptable low energy fiber enriched and diabetic jams, cakes and biscuits using different formulas of sucrose substitutes with the partial replacement of wheat flour with bran as a source of dietary fibre, was studied. Special care was paid to evaluate the nutritional plus keeping qualities and the potential effect of the most acceptable formulae from each food stuffs group on the blood glucose level in lean and obese diabetes mellitus patients. It was technologically possible to prepare acceptable, high nutritional diabetic and low energy apricot, guava and strawberry jams and jellies by combinations of sweeteners using xylitol (i.e. xylitol-sorbitol-aspartame and xylitol-fructose). The attainment of a suitable texture may be more difficult in xylitol and sorbitol jams, therefore 0.2 g CaCl2. 2H2O was added. Storage of these jams at 4 degrees C improved their keeping quality significantly (p < 0.05), where the microbial load was less than 20 cells per gram and the products were free from molds and yeasts. Also, high nutritional and acceptable cakes and biscuits for low energy supply and for diabetic subjects can be sweetened with low level of aspartame in combination with fructose, sorbitol and xylitol. Consumption of such low energic and diabetic food items reduces significantly (p < 0.05) the plasma glucose level in lean and obese diabetics. Addition of wheat bran in bakery products not only reduced both energy value of these foods and blood glucose, but it also improved peripheral insulin activity by its system modification.

Late Holocene earthquakes on the Toe Jam Hill fault, Seattle fault zone, Bainbridge Island, Washington

USGS Publications Warehouse

Nelson, A.R.; Johnson, S.Y.; Kelsey, H.M.; Wells, R.E.; Sherrod, B.L.; Pezzopane, S.K.; Bradley, L.A.; Koehler, R. D.; Bucknam, R.C.

2003-01-01

Five trenches across a Holocene fault scarp yield the first radiocarbon-measured earthquake recurrence intervals for a crustal fault in western Washington. The scarp, the first to be revealed by laser imagery, marks the Toe Jam Hill fault, a north-dipping backthrust to the Seattle fault. Folded and faulted strata, liquefaction features, and forest soil A horizons buried by hanging-wall-collapse colluvium record three, or possibly four, earthquakes between 2500 and 1000 yr ago. The most recent earthquake is probably the 1050-1020 cal. (calibrated) yr B.P. (A.D. 900-930) earthquake that raised marine terraces and triggered a tsunami in Puget Sound. Vertical deformation estimated from stratigraphic and surface offsets at trench sites suggests late Holocene earthquake magnitudes near M7, corresponding to surface ruptures >36 km long. Deformation features recording poorly understood latest Pleistocene earthquakes suggest that they were smaller than late Holocene earthquakes. Postglacial earthquake recurrence intervals based on 97 radiocarbon ages, most on detrital charcoal, range from ???12,000 yr to as little as a century or less; corresponding fault-slip rates are 0.2 mm/yr for the past 16,000 yr and 2 mm/yr for the past 2500 yr. Because the Toe Jam Hill fault is a backthrust to the Seattle fault, it may not have ruptured during every earthquake on the Seattle fault. But the earthquake history of the Toe Jam Hill fault is at least a partial proxy for the history of the rest of the Seattle fault zone.

Multifrequency OFDM SAR in Presence of Deception Jamming

NASA Astrophysics Data System (ADS)

Schuerger, Jonathan; Garmatyuk, Dmitriy

2010-12-01

Orthogonal frequency division multiplexing (OFDM) is considered in this paper from the perspective of usage in imaging radar scenarios with deception jamming. OFDM radar signals are inherently multifrequency waveforms, composed of a number of subbands which are orthogonal to each other. While being employed extensively in communications, OFDM has not found comparatively wide use in radar, and, particularly, in synthetic aperture radar (SAR) applications. In this paper, we aim to show the advantages of OFDM-coded radar signals with random subband composition when used in deception jamming scenarios. Two approaches to create a radar signal by the jammer are considered: instantaneous frequency (IF) estimator and digital-RF-memory- (DRFM-) based reproducer. In both cases, the jammer aims to create a copy of a valid target image via resending the radar signal at prescribed time intervals. Jammer signals are derived and used in SAR simulations with three types of signal models: OFDM, linear frequency modulated (LFM), and frequency-hopped (FH). Presented results include simulated peak side lobe (PSL) and peak cross-correlation values for random OFDM signals, as well as simulated SAR imagery with IF and DRFM jammers'-induced false targets.

Simple effective rule to estimate the jamming packing fraction of polydisperse hard spheres.

PubMed

Santos, Andrés; Yuste, Santos B; López de Haro, Mariano; Odriozola, Gerardo; Ogarko, Vitaliy

2014-04-01

A recent proposal in which the equation of state of a polydisperse hard-sphere mixture is mapped onto that of the one-component fluid is extrapolated beyond the freezing point to estimate the jamming packing fraction ϕJ of the polydisperse system as a simple function of M1M3/M22, where Mk is the kth moment of the size distribution. An analysis of experimental and simulation data of ϕJ for a large number of different mixtures shows a remarkable general agreement with the theoretical estimate. To give extra support to the procedure, simulation data for seventeen mixtures in the high-density region are used to infer the equation of state of the pure hard-sphere system in the metastable region. An excellent collapse of the inferred curves up to the glass transition and a significant narrowing of the different out-of-equilibrium glass branches all the way to jamming are observed. Thus, the present approach provides an extremely simple criterion to unify in a common framework and to give coherence to data coming from very different polydisperse hard-sphere mixtures.

Demonstration of an RF front-end based on GaN HEMT technology

NASA Astrophysics Data System (ADS)

Ture, Erdin; Musser, Markus; Hülsmann, Axel; Quay, Rüdiger; Ambacher, Oliver

2017-05-01

The effectiveness of the developed front-end on blocking the communication link of a commercial drone vehicle has been demonstrated in this work. A jamming approach has been taken in a broadband fashion by using GaN HEMT technology. Equipped with a modulated-signal generator, a broadband power amplifier, and an omni-directional antenna, the proposed system is capable of producing jamming signals in a very wide frequency range between 0.1 - 3 GHz. The maximum RF output power of the amplifier module has been software-limited to 27 dBm (500 mW), complying to the legal spectral regulations of the 2.4 GHz ISM band. In order to test the proof of concept, a real-world scenario has been prepared in which a commercially-available quadcopter UAV is flown in a controlled environment while the jammer system has been placed in a distance of about 10 m from the drone. It has been proven that the drone of interest can be neutralized as soon as it falls within the range of coverage (˜3 m) which endorses the promising potential of the broadband jamming approach.

Percolation of disordered jammed sphere packings

NASA Astrophysics Data System (ADS)

Ziff, Robert M.; Torquato, Salvatore

2017-02-01

We determine the site and bond percolation thresholds for a system of disordered jammed sphere packings in the maximally random jammed state, generated by the Torquato-Jiao algorithm. For the site threshold, which gives the fraction of conducting versus non-conducting spheres necessary for percolation, we find {{p}\\text{c}}=0.3116(3) , consistent with the 1979 value of Powell 0.310(5) and identical within errors to the threshold for the simple-cubic lattice, 0.311 608, which shares the same average coordination number of 6. In terms of the volume fraction ϕ, the threshold corresponds to a critical value {φ\\text{c}}=0.199 . For the bond threshold, which apparently was not measured before, we find {{p}\\text{c}}=0.2424(3) . To find these thresholds, we considered two shape-dependent universal ratios involving the size of the largest cluster, fluctuations in that size, and the second moment of the size distribution; we confirmed the ratios’ universality by also studying the simple-cubic lattice with a similar cubic boundary. The results are applicable to many problems including conductivity in random mixtures, glass formation, and drug loading in pharmaceutical tablets.

Modeling and simulation of driver's anticipation effect in a two lane system on curved road with slope

NASA Astrophysics Data System (ADS)

Kaur, Ramanpreet; Sharma, Sapna

2018-06-01

The complexity of traffic flow phenomena on curved road with slope is investigated and a new lattice model is presented with the addition of driver's anticipation effect for two lane system. The condition under which the free flow turns into the jammed one, is obtained theoretically by using stability analysis. The results obtained through linear analysis indicates that the stable region increases (decreases) corresponding to uphill (downhill) case due to increasing slope angle for fixed anticipation parameter. It is found that when the vehicular density becomes higher than a critical value, traffic jam appears in the form of kink antikink density waves. Analytically, the kink antikink density waves are described by the solution of mKdV equation obtained from non linear analysis. In addition, the theoretical results has been verified through numerical simulation, which confirm that the slope on a curved highway significantly influence the traffic dynamics and traffic jam can be suppressed efficiently by considering the anticipation parameter in a two lane lattice model when lane changing is allowed.

KSC-2012-1551

NASA Image and Video Library

2012-02-23

ORLANDO, Fla. -- Visitors enter the Orange County Convention Center in Orlando, Fla., for the NBA All-Star Jam Session. Representatives from NASA's Kennedy Space Center in Florida were available to highlight some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

KSC-2012-1556

NASA Image and Video Library

2012-02-23

ORLANDO, Fla. -- Representatives from NASA's Kennedy Space Center in Florida talk to visitors attending the NBA All-Star Jam Session at the Orange County Convention Center in Orlando, Fla. The NASA exhibit offers hands-on educational activities highlighting some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

Performance comparison of ISAR imaging method based on time frequency transforms

NASA Astrophysics Data System (ADS)

Xie, Chunjian; Guo, Chenjiang; Xu, Jiadong

2013-03-01

Inverse synthetic aperture radar (ISAR) can image the moving target, especially the target in the air, so it is important in the air defence and missile defence system. Time-frequency Transform was applied to ISAR imaging process widely. Several time frequency transforms were introduced. Noise jamming methods were analysed, and when these noise jamming were added to the echo of the ISAR receiver, the image can become blur even can't to be identify. But the effect is different to the different time frequency analysis. The results of simulation experiment show the Performance Comparison of the method.

Viscosity of particulate soap films: approaching the jamming of 2D capillary suspensions.

PubMed

Timounay, Yousra; Rouyer, Florence

2017-05-14

We compute the effective viscosity of particulate soap films thanks to local velocity fields obtained by Particle Image Velocimetry (PIV) during film retraction experiments. We identify the jamming of these 2D capillary suspensions at a critical particle surface fraction (≃0.84) where effective viscosity diverges. Pair correlation function and number of neighbors in contact or close to contact reveal the cohesive nature of this 2D capillary granular media. The experimental 2D dynamic viscosities can be predicted by a model considering viscous dissipation at the liquid interfaces induced by the motion of individual particles.

Machine Monitor

NASA Technical Reports Server (NTRS)

1994-01-01

When a printing press jams, damage is extensive, repairs are costly, and time and production loss can be expensive. James River Corporation requested G.W. Shelton, a design engineer with Logical Control Systems to solve this problem. Shelton found the solution in a NASA Tech Brief article describing a system of pulley and belt drives. This led to the design of a system that monitors drive components for changes in relative speed that would indicate belt slippage and jam probability. When a combination of variables is not met, an emergency "stop" signal is sent to the press and an alarm is triggered.

KSC-2012-1554

NASA Image and Video Library

2012-02-23

ORLANDO, Fla. -- Inside the Orange County Convention Center in Orlando, Fla., representatives from NASA's Kennedy Space Center in Florida speak to attendees visiting the NBA All-Star Jam Session. The NASA exhibit offers hands-on educational activities highlighting some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

KSC-2012-1553

NASA Image and Video Library

2012-02-23

ORLANDO, Fla. -- Inside the Orange County Convention Center in Orlando, Fla., representatives from NASA's Kennedy Space Center in Florida speak to attendees visiting the NBA All-Star Jam Session. The NASA exhibit offers hands-on educational activities highlighting some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

Intrinsic development of choroidal and thalamic collaterals in hemorrhagic-onset moyamoya disease: case-control study of the Japan Adult Moyamoya Trial.

PubMed

Fujimura, Miki; Funaki, Takeshi; Houkin, Kiyohiro; Takahashi, Jun C; Kuroda, Satoshi; Tomata, Yasutake; Tominaga, Teiji; Miyamoto, Susumu

2018-05-04

OBJECTIVE This study was performed to identify the angiographic features of hemorrhagic-onset moyamoya disease (MMD) in comparison with those of patients with ischemic-onset MMD. METHODS This case-control study compared the data set of the Japan Adult Moyamoya (JAM) Trial with the angiographic data of adult patients with ischemic-onset MMD. The authors analyzed angiograms obtained at onset, classifying the collaterals into 3 subtypes: lenticulostriate anastomosis, thalamic anastomosis, and choroidal anastomosis. They then compared the extent of these collaterals, as indicated by the collateral development grade from 0 to 2 in each subtype, between the JAM Trial group and the ischemic-onset group. They also compared the involvement of the posterior cerebral artery (PCA) and Suzuki's angiographic staging between each group. RESULTS Among 89 ischemic-onset patients, 103 symptomatic hemispheres in 80 patients were analyzed and compared with 75 hemorrhagic hemispheres from the JAM Trial. The hemorrhagic-onset patients showed a significantly higher proportion of thalamic anastomosis (p = 0.043) and choroidal anastomosis (< 0.001), as indicated by grade 2 in each subtype, compared with ischemic-onset patients. Suzuki's angiographic staging was significantly higher in the hemorrhagic group (< 0.038). There was no difference in the extent of lenticulostriate anastomosis and PCA involvement between the groups. CONCLUSIONS In adult MMD, the characteristic pattern of the abnormal vascular networks at the base of the brain is different between each onset type. In light of the more prominent development of thalamic and choroidal anastomosis in the JAM Trial group in the present study, development of these collaterals, especially the choroidal collateral extending beyond the lateral ventricle, may play a critical role in hemorrhagic presentation in MMD. Clinical trial registration no. C000000166 ( http://www.umin.ac.jp/ctr/index.htm ).

A model of irreversible jam formation in dense traffic

NASA Astrophysics Data System (ADS)

Brankov, J. G.; Bunzarova, N. Zh.; Pesheva, N. C.; Priezzhev, V. B.

2018-03-01

We study an one-dimensional stochastic model of vehicular traffic on open segments of a single-lane road of finite size L. The vehicles obey a stochastic discrete-time dynamics which is a limiting case of the generalized Totally Asymmetric Simple Exclusion Process. This dynamics has been previously used by Bunzarova and Pesheva (2017) for an one-dimensional model of irreversible aggregation. The model was shown to have three stationary phases: a many-particle one, MP, a phase with completely filled configuration, CF, and a boundary perturbed MP+CF phase, depending on the values of the particle injection (α), ejection (β) and hopping (p) probabilities. Here we extend the results for the stationary properties of the MP+CF phase, by deriving exact expressions for the local density at the first site of the chain and the probability P(1) of a completely jammed configuration. The unusual phase transition, characterized by jumps in both the bulk density and the current (in the thermodynamic limit), as α crosses the boundary α = p from the MP to the CF phase, is explained by the finite-size behavior of P(1). By using a random walk theory, we find that, when α approaches from below the boundary α = p, three different regimes appear, as the size L → ∞: (i) the lifetime of the gap between the rightmost clusters is of the order O(L) in the MP phase; (ii) small jams, separated by gaps with lifetime O(1) , exist in the MP+CF phase close to the left chain boundary; and (iii) when β = p, the jams are divided by gaps with lifetime of the order O(L 1 / 2) . These results are supported by extensive Monte Carlo calculations.

Systematic autistic-like behavioral phenotyping of 4 mouse strains using a novel wheel-running assay.

PubMed

Karvat, Golan; Kimchi, Tali

2012-08-01

Three core symptoms of autistic spectrum disorders are stereotypic movements, resistance to change in routines and deficits in social interaction. In order to understand their neuronal mechanisms, there is a dire need for behavioral paradigms to assess those symptoms in rodents. Here we present a novel method which is based on positive reward in a customized wheel-running apparatus to assess these symptoms. As a proof of concept, 4 mouse strains were tested in the new behavioral paradigm; 2 control lines (C57BL/6 and ICR) and 2 mouse-models of autism (BTBR T+ tf/J and Nlgn3(tm1Sud)). We found that the C57BL/6, ICR and Nlgn3(tm1Sud) mice showed a significant reduction in stereotypical behavior in the presence of the running wheel, ability to forfeit the running habit when the running-wheel was jammed, and preference of interacting with a social stimulus over the jammed running-wheel. No difference was found between genotypes of the Nlgn3(tm1Sud) mice. On the other hand, the BTBR mice exhibited persistent, elevated levels of stereotypical behavior. In addition, they presented a deficit in their ability to adjust to a changing environment, as manifested in persistence to interact with the wheel even when it was jammed. Lastly, the BTBR mice exhibited no significant preference to interact with the stranger mouse over the jammed running-wheel. These results were validated by a set of commonly used behavioral tests. Overall, our novel behavioral paradigm detects multiple components of autistic-like phenotypes, including cognitive rigidity, stereotypic behavior and social deficiency. Copyright © 2012 Elsevier B.V. All rights reserved.

Predicting Road Conditions with Internet Search

PubMed Central

2016-01-01

Traffic congestion is an important problem both on an individual and on a societal level and much research has been done to explain and prevent their emergence. There are currently many systems which provide a reasonably good picture of actual road traffic by employing either fixed measurement points on highways or so called “floating car data” i.e. by using velocity and location data from roaming, networked, GPS enabled members of traffic. Some of these systems also offer forecasting of road conditions based on such historical data. To my knowledge there is as yet no system which offers advance notice on road conditions based on a signal which is guaranteed to occur in advance of these conditions and this is the novelty of this paper. Google Search intensity for the German word stau (i.e. traffic jam) peaks 2 hours ahead of the number of traffic jam reports as reported by the ADAC, a well known German automobile club and the largest of its kind in Europe. This is true both in the morning (7 am to 9 am) and in the evening (4 pm to 6 pm). The main result of this paper is then that after controlling for time-of-day and day-of-week effects we can still explain a significant additional portion of the variation of the number of traffic jam reports with Google Trends and we can thus explain well over 80% of the variation of road conditions using Google search activity. A one percent increase in Google stau searches implies a .4 percent increase of traffic jams. Our paper is a proof of concept that aggregate, timely delivered behavioural data can help fine tune modern societies and prompts for more research with better, more disaggregated data in order to also achieve practical solutions. PMID:27571518

APOC3 induces endothelial dysfunction through TNF-α and JAM-1.

PubMed

Tao, Yun; Xiong, Yisong; Wang, Huimin; Chu, Shaopeng; Zhong, Renqian; Wang, Jianxin; Wang, Guihua; Ren, Xiumei; Yu, Juan

2016-09-13

The fatality rate for cardiovascular disease (CVD) has increased in recent years and higher levels of triglyceride have been shown to be an independent risk factor for atherosclerotic CVD. Dysfunction of endothelial cells (ECs) is also a key factor of CVD. APOC3 is an important molecule in lipid metabolism that is closely associated with hyperlipidemia and an increased risk of developing CVD. But the direct effects of APOC3 on ECs were still unknown. This study was aimed at determining the effects of APOC3 on inflammation, chemotaxis and exudation in ECs. ELISA, qRT-PCR, immunofluorescence, flow cytometry and transwell assays were used to investigate the effects of APOC3 on human umbilical vein endothelial cells (HUVECs). SiRNA-induced TNF-α and JAM-1 silencing were used to observe how APOC3 influenced the inflammatory process in the ECs. Our results showed that APOC3 was closely associated with the inflammatory process in ECs, and that this process was characterized by the increased expression of TNF-α. Inflammatory processes further disrupted the tight junctions (TJs) between HUVECs by causing increased expression of JAM-1. JAM-1 was involved in maintaining the integrity of TJs, and it promoted the assembly of platelets and the exudation of leukocytes. Changes in its expression promoted chemotaxis and the exudation of ECs, which contributed to atherosclerosis. While the integrity of the TJs was disrupted, the adhesion of THP-1 cells to HUVECs was also increased by APOC3. In this study, we describe the mechanism by which APOC3 causes inflammation, chemotaxis and the exudation of ECs, and we suggest that controlling the inflammatory reactions that are caused by APOC3 may be a new method to treat CVD.

Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens

PubMed Central

Lucon, Enrico; McCowan, Chris N.; Santoyo, Ray L.

2015-01-01

The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of −40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e., the experimental scatter) is reduced when testing at room temperature. For eight out of the nine lots considered, the observed variability was lower at 21 °C than at −40 °C. The results of this study will allow NIST to satisfy requests for room-temperature Charpy verification specimens that have been received from customers for several years: testing at 21 °C removes from the verification process the operator’s skill in transferring the specimen in a timely fashion from the cooling bath to the impact position, and puts the focus back on the machine performance. For NIST, it also reduces the time and cost for certifying new verification lots. For one of the low-energy lots tested with a C-shaped hammer, we experienced two specimens jamming, which yielded unusually high values of absorbed energy. For both specimens, the signs of jamming were clearly visible. For all the low-energy lots investigated, jamming is slightly more likely to occur at 21 °C than at −40 °C, since at room temperature low-energy samples tend to remain in the test area after impact rather than exiting in the opposite direction of the pendulum swing. In the evaluation of a verification set, any jammed specimen should be removed from the analyses. PMID:26958453

Involvement of the interaction of afadin with ZO-1 in the formation of tight junctions in Madin-Darby canine kidney cells.

PubMed

Ooshio, Takako; Kobayashi, Reiko; Ikeda, Wataru; Miyata, Muneaki; Fukumoto, Yuri; Matsuzawa, Naomi; Ogita, Hisakazu; Takai, Yoshimi

2010-02-12

Tight junctions (TJs) and adherens junctions (AJs) are major junctional apparatuses in epithelial cells. Claudins and junctional adhesion molecules (JAMs) are major cell adhesion molecules (CAMs) at TJs, whereas cadherins and nectins are major CAMs at AJs. Claudins and JAMs are associated with ZO proteins, whereas cadherins are associated with beta- and alpha-catenins, and nectins are associated with afadin. We previously showed that nectins first form cell-cell adhesions where the cadherin-catenin complex is recruited to form AJs, followed by the recruitment of the JAM-ZO and claudin-ZO complexes to the apical side of AJs to form TJs. It is not fully understood how TJ components are recruited to the apical side of AJs. We studied the roles of afadin and ZO-1 in the formation of TJs in Madin-Darby canine kidney (MDCK) cells. Before the formation of TJs, ZO-1 interacted with afadin through the two proline-rich regions of afadin and the SH3 domain of ZO-1. During and after the formation of TJs, ZO-1 dissociated from afadin and associated with JAM-A. Knockdown of afadin impaired the formation of both AJs and TJs in MDCK cells, whereas knockdown of ZO-1 impaired the formation of TJs, but not AJs. Re-expression of full-length afadin restored the formation of both AJs and TJs in afadin-knockdown MDCK cells, whereas re-expression of afadin-DeltaPR1-2, which is incapable of binding to ZO-1, restored the formation of AJs, but not TJs. These results indicate that the transient interaction of afadin with ZO-1 is necessary for the formation of TJs in MDCK cells.

Involvement of the Interaction of Afadin with ZO-1 in the Formation of Tight Junctions in Madin-Darby Canine Kidney Cells*

PubMed Central

Ooshio, Takako; Kobayashi, Reiko; Ikeda, Wataru; Miyata, Muneaki; Fukumoto, Yuri; Matsuzawa, Naomi; Ogita, Hisakazu; Takai, Yoshimi

2010-01-01

Tight junctions (TJs) and adherens junctions (AJs) are major junctional apparatuses in epithelial cells. Claudins and junctional adhesion molecules (JAMs) are major cell adhesion molecules (CAMs) at TJs, whereas cadherins and nectins are major CAMs at AJs. Claudins and JAMs are associated with ZO proteins, whereas cadherins are associated with β- and α-catenins, and nectins are associated with afadin. We previously showed that nectins first form cell-cell adhesions where the cadherin-catenin complex is recruited to form AJs, followed by the recruitment of the JAM-ZO and claudin-ZO complexes to the apical side of AJs to form TJs. It is not fully understood how TJ components are recruited to the apical side of AJs. We studied the roles of afadin and ZO-1 in the formation of TJs in Madin-Darby canine kidney (MDCK) cells. Before the formation of TJs, ZO-1 interacted with afadin through the two proline-rich regions of afadin and the SH3 domain of ZO-1. During and after the formation of TJs, ZO-1 dissociated from afadin and associated with JAM-A. Knockdown of afadin impaired the formation of both AJs and TJs in MDCK cells, whereas knockdown of ZO-1 impaired the formation of TJs, but not AJs. Re-expression of full-length afadin restored the formation of both AJs and TJs in afadin-knockdown MDCK cells, whereas re-expression of afadin-ΔPR1–2, which is incapable of binding to ZO-1, restored the formation of AJs, but not TJs. These results indicate that the transient interaction of afadin with ZO-1 is necessary for the formation of TJs in MDCK cells. PMID:20008323

Certification of NIST Room Temperature Low-Energy and High-Energy Charpy Verification Specimens.

PubMed

Lucon, Enrico; McCowan, Chris N; Santoyo, Ray L

2015-01-01

The possibility for NIST to certify Charpy reference specimens for testing at room temperature (21 °C ± 1 °C) instead of -40 °C was investigated by performing 130 room-temperature tests from five low-energy and four high-energy lots of steel on the three master Charpy machines located in Boulder, CO. The statistical analyses performed show that in most cases the variability of results (i.e., the experimental scatter) is reduced when testing at room temperature. For eight out of the nine lots considered, the observed variability was lower at 21 °C than at -40 °C. The results of this study will allow NIST to satisfy requests for room-temperature Charpy verification specimens that have been received from customers for several years: testing at 21 °C removes from the verification process the operator's skill in transferring the specimen in a timely fashion from the cooling bath to the impact position, and puts the focus back on the machine performance. For NIST, it also reduces the time and cost for certifying new verification lots. For one of the low-energy lots tested with a C-shaped hammer, we experienced two specimens jamming, which yielded unusually high values of absorbed energy. For both specimens, the signs of jamming were clearly visible. For all the low-energy lots investigated, jamming is slightly more likely to occur at 21 °C than at -40 °C, since at room temperature low-energy samples tend to remain in the test area after impact rather than exiting in the opposite direction of the pendulum swing. In the evaluation of a verification set, any jammed specimen should be removed from the analyses.

Constitutive relation for the system-spanning dynamically jammed region in response to impact of cornstarch and water suspensions

NASA Astrophysics Data System (ADS)

Maharjan, Rijan; Mukhopadhyay, Shomeek; Allen, Benjamin; Storz, Tobias; Brown, Eric

2018-05-01

We experimentally characterize the impact response of concentrated suspensions consisting of cornstarch and water. We observe that the suspensions support a large normal stress—on the order of MPa—with a delay after the impactor hits the suspension surface. We show that neither the delay nor the magnitude of the stress can yet be explained by either standard rheological models of shear thickening in terms of steady-state viscosities, or impact models based on added mass or other inertial effects. The stress increase occurs when a dynamically jammed region of the suspension in front of the impactor propagates to the opposite boundary of the container, which can support large stresses when it spans between solid boundaries. We present a constitutive relation for impact rheology to relate the force on the impactor to its displacement. This can be described in terms of an effective modulus but only after the delay required for the dynamically jammed region to span between solid boundaries. Both the modulus and the delay are reported as a function of impact velocity, fluid height, and weight fraction. We report in a companion paper the structure of the dynamically jammed region when it spans between the impactor and the opposite boundary [Allen et al., Phys. Rev. E 97, 052603 (2018), 10.1103/PhysRevE.97.052603]. In a direct follow-up paper, we show that this constitutive model can be used to quantitatively predict, for example, the trajectory and penetration depth of the foot of a person walking or running on cornstarch and water [Mukhopadhyay et al., Phys. Rev. E 97, 052604 (2018), 10.1103/PhysRevE.97.052604].

Skylab

NASA Image and Video Library

1973-05-01

This photograph was taken during testing of an emergency procedure to free jammed solar array panels on the Skylab workshop. A metal strap became tangled over one of the folded solar array panels when Skylab lost its micrometeoroid shield during the launch. This photograph shows astronauts Schweickart and Gibson in the Marshall Space Flight Center (MSFC) Neutral Buoyancy Simulator (NBS) using various cutting tools and methods developed by the MSFC to free the jammed solar wing. Extensive testing and many hours of practice in simulators such as the NBS tank helped prepare the Skylab crewmen for extravehicular performance in the weightless environment. This huge water tank simulated the weightless environment that the astronauts would encounter in space.

KSC-2012-1557

NASA Image and Video Library

2012-02-23

ORLANDO, Fla. -- A representative from NASA's Kennedy Space Center in Florida speaks with a young visitor attending the NBA All-Star Jam Session at the Orange County Convention Center in Orlando, Fla. The NASA exhibit offers hands-on educational activities highlighting some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

Coarse analysis of collective behaviors: Bifurcation analysis of the optimal velocity model for traffic jam formation

NASA Astrophysics Data System (ADS)

Miura, Yasunari; Sugiyama, Yuki

2017-12-01

We present a general method for analyzing macroscopic collective phenomena observed in many-body systems. For this purpose, we employ diffusion maps, which are one of the dimensionality-reduction techniques, and systematically define a few relevant coarse-grained variables for describing macroscopic phenomena. The time evolution of macroscopic behavior is described as a trajectory in the low-dimensional space constructed by these coarse variables. We apply this method to the analysis of the traffic model, called the optimal velocity model, and reveal a bifurcation structure, which features a transition to the emergence of a moving cluster as a traffic jam.

KSC-2012-1555

NASA Image and Video Library

2012-02-23

ORLANDO, Fla. -- Visitors to the NBA All-Star Jam Session at the Orange County Convention Center in Orlando, Fla., use a large touch-screen to learn more about NASA's activities and missions. Representatives from Kennedy Space Center in Florida helped attendees participate in hands-on educational activities to learn more about how science plays into sports. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

Jamming and liquidity in 3D cancer cell aggregates

NASA Astrophysics Data System (ADS)

Oswald, Linda; Grosser, Steffen; Lippoldt, Jürgen; Pawlizak, Steve; Fritsch, Anatol; KäS, Josef A.

Traditionally, tissues are treated as simple liquids, which holds for example for embryonic tissue. However, recent experiments have shown that this picture is insufficient for other tissue types, suggesting possible transitions to solid-like behavior induced by cellular jamming. The coarse-grained self-propelled Voronoi (SPV) model predicts such a transition depending on cell shape which is thought to arise from an interplay of cell-cell adhesion and cortical tension. We observe non-liquid behavior in 3D breast cancer spheroids of varying metastatic potential and correlate single cell shapes, single cell dynamics and collective dynamic behavior of fusion and segregation experiments via the SPV model.

KSC-2012-1558

NASA Image and Video Library

2012-02-23

ORLANDO, Fla. -- A representative from NASA's Kennedy Space Center in Florida speaks with a young visitor attending the NBA All-Star Jam Session at the Orange County Convention Center in Orlando, Fla. The NASA exhibit offers hands-on educational activities highlighting some of the contributions the space agency has made to sports, transportation and everyday life. One of the events leading up to the NBA All-Star game being held in Orlando on Feb. 26, the NBA All-Star Jam Session is a basketball experience intended for all ages, allowing fans to compete against their friends in skills challenges and collect autographs from players and legends. Photo credit: NASA/Frankie Martin

Modeling perspectives on echolocation strategies inspired by bats flying in groups.

PubMed

Lin, Yuan; Abaid, Nicole

2015-12-21

Bats navigating with echolocation - which is a type of active sensing achieved by interpreting echoes resulting from self-generated ultrasonic pulses - exhibit unique behaviors during group flight. While bats may benefit from eavesdropping on their peers׳ echolocation, they also potentially suffer from confusion between their own and peers׳ pulses, caused by an effect called frequency jamming. This hardship of group flight is supported by experimental observations of bats simplifying their sound-scape by shifting their pulse frequencies or suppressing echolocation altogether. Here, we investigate eavesdropping and varying pulse emission rate from a modeling perspective to understand these behaviors׳ potential benefits and detriments. We define an agent-based model of echolocating bats avoiding collisions in a three-dimensional tunnel. Through simulation, we show that bats with reasonably accurate eavesdropping can reduce collisions compared to those neglecting information from peers. In large populations, bats minimize frequency jamming by decreasing pulse emission rate, while collision risk increases; conversely, increasing pulse emission rate minimizes collisions by allowing more sensing information generated per bat. These strategies offer benefits for both biological and engineered systems, since frequency jamming is a concern in systems using active sensing. Copyright © 2015 Elsevier Ltd. All rights reserved.

Jammed elastic shells - a 3D experimental soft frictionless granular system

NASA Astrophysics Data System (ADS)

Jose, Jissy; Blab, Gerhard A.; van Blaaderen, Alfons; Imhof, Arnout

2015-03-01

We present a new experimental system of monodisperse, soft, frictionless, fluorescent labelled elastic shells for the characterization of structure, universal scaling laws and force networks in 3D jammed matter. The interesting fact about these elastic shells is that they can reversibly deform and therefore serve as sensors of local stress in jammed matter. Similar to other soft particles, like emulsion droplets and bubbles in foam, the shells can be packed to volume fractions close to unity, which allows us to characterize the contact force distribution and universal scaling laws as a function of volume fraction, and to compare them with theoretical predictions and numerical simulations. However, our shells, unlike other soft particles, deform rather differently at large stresses. They deform without conserving their inner volume, by forming dimples at contact regions. At each contact one of the shells buckled with a dimple and the other remained spherical, closely resembling overlapping spheres. We conducted 3D quantitative analysis using confocal microscopy and image analysis routines specially developed for these particles. In addition, we analysed the randomness of the process of dimpling, which was found to be volume fraction dependent.

Highly Dynamic and Adaptive Traffic Congestion Avoidance in Real-Time Inspired by Honey Bee Behavior

NASA Astrophysics Data System (ADS)

Wedde, Horst F.; Lehnhoff, Sebastian; van Bonn, Bernhard; Bay, Z.; Becker, S.; Böttcher, S.; Brunner, C.; Büscher, A.; Fürst, T.; Lazarescu, A. M.; Rotaru, E.; Senge, S.; Steinbach, B.; Yilmaz, F.; Zimmermann, T.

Traffic congestions have become a major problem in metropolitan areas world-wide, within and between cities, to an extent where they make driving and transportation times largely unpredictable. Due to the highly dynamic character of congestion building and dissolving this phenomenon appears even to resist a formal treatment. Static approaches, and even more their global management, have proven counterproductive in practice. Given the latest progress in VANET technology and the remarkable commercially driven efforts like in the European C2C consortium, or the VSC Project in the US, allow meanwhile to tackle various aspects of traffic regulation through VANET communication. In this paper we introduce a novel, completely decentralized multi-agent routing algorithm (termed BeeJamA) which we have derived from the foraging behavior of honey bees. It is highly dynamic, adaptive, robust, and scalable, and it allows for both avoiding congestions, and minimizing traveling times to individual destinations. Vehicle guidance is provided well ahead of every intersection, depending on the individual speeds. Thus strict deadlines are imposed on, and respected by, the BeeJamA algorithm. We report on extensive simulation experiments which show the superior performance of BeeJamA over conventional approaches.

PRKAG3 and CAST genetic polymorphisms and quality traits of dry-cured hams--I. Associations in Spanish dry-cured ham Jamón Serrano.

PubMed

Gou, P; Zhen, Z Y; Hortós, M; Arnau, J; Diestre, A; Robert, N; Claret, A; Čandek-Potokar, M; Santé-Lhoutellier, V

2012-12-01

The functional single polymorphisms identified in the calpastatin (CAST) gene have been related to the rate of meat tenderization and the protein turnover after slaughter, and the Ile199Val polymorphism identified in the coding region of the protein kinase AMP-activated (PRKAG3) gene has been proven to affect ultimate pH in muscle. The aim of the present study was to show the effects of these genetic polymorphisms on the quality traits of Spanish dry-cured ham Jamón Serrano. A tissue sample from 665 crossbreed pigs were genotyped for PRKAG3 Ile199Val, CAST Arg249Lys and CAST Ser638Arg polymorphisms, and a subsample of 120 dry cured hams was selected to perform physico-chemical, rheological, instrumental colour and sensory analyses. Associations between the polymorphisms and several quality traits of dry-cured ham, mainly related to flavour and texture, were found. The genotypes PRKAG3 Ile/Ile, CAST249 Arg/Arg and CAST638 Arg/Arg, and the haplotype CAST 249Arg-638Arg were the most favourable for Jamón Serrano production. Copyright © 2012 Elsevier Ltd. All rights reserved.

Jamming II: Edwards’ statistical mechanics of random packings of hard spheres

NASA Astrophysics Data System (ADS)

Wang, Ping; Song, Chaoming; Jin, Yuliang; Makse, Hernán A.

2011-02-01

The problem of finding the most efficient way to pack spheres has an illustrious history, dating back to the crystalline arrays conjectured by Kepler and the random geometries explored by Bernal in the 1960s. This problem finds applications spanning from the mathematician’s pencil, the processing of granular materials, the jamming and glass transitions, all the way to fruit packing in every grocery. There are presently numerous experiments showing that the loosest way to pack spheres gives a density of ∼55% (named random loose packing, RLP) while filling all the loose voids results in a maximum density of ∼63%-64% (named random close packing, RCP). While those values seem robustly true, to this date there is no well-accepted physical explanation or theoretical prediction for them. Here we develop a common framework for understanding the random packings of monodisperse hard spheres whose limits can be interpreted as the experimentally observed RLP and RCP. The reason for these limits arises from a statistical picture of jammed states in which the RCP can be interpreted as the ground state of the ensemble of jammed matter with zero compactivity, while the RLP arises in the infinite compactivity limit. We combine an extended statistical mechanics approach ‘a la Edwards’ (where the role traditionally played by the energy and temperature in thermal systems is substituted by the volume and compactivity) with a constraint on mechanical stability imposed by the isostatic condition. We show how such approaches can bring results that can be compared to experiments and allow for an exploitation of the statistical mechanics framework. The key result is the use of a relation between the local Voronoi volumes of the constituent grains (denoted the volume function) and the number of neighbors in contact that permits us to simply combine the two approaches to develop a theory of volume fluctuations in jammed matter. Ultimately, our results lead to a phase diagram that provides a unifying view of the disordered hard sphere packing problem and further sheds light on a diverse spectrum of data, including the RLP state. Theoretical results are well reproduced by numerical simulations that confirm the essential role played by friction in determining both the RLP and RCP limits. The RLP values depend on friction, explaining why varied experimental results can be obtained.

A compound control strategy combining velocity compensation with ADRC of electro-hydraulic position servo control system.

PubMed

Gao, Bingwei; Shao, Junpeng; Yang, Xiaodong

2014-11-01

In order to enhance the anti-jamming ability of electro-hydraulic position servo control system at the same time improve the control precision of the system, a compound control strategy that combines velocity compensation with Active Disturbance Rejection Controller (ADRC) is proposed, and the working principle of the compound control strategy is given. ADRC controller is designed, and the extended state observer is used for observing internal parameters uncertainties and external disturbances, so that the disturbances of the system are suppressed effectively. Velocity compensation controller is designed and the compensation model is derived to further improve the positioning accuracy of the system and to achieve the velocity compensation without disturbance. The compound control strategy is verified by the simulation and experiment respectively, and the simulation and experimental results show that the electro-hydraulic position servo control system with ADRC controller can effectively inhibit the external disturbances, the precise positioning control is realized after introducing the velocity compensation controller, and verify that the compound control strategy is effective. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

Low loss jammed-array wideband sawtooth filter based on a finite reflection virtually imaged array

NASA Astrophysics Data System (ADS)

Tan, Zhongwei; Cao, Dandan; Ding, Zhichao

2018-03-01

An edge filter is a potential technology in the fiber Bragg grating interrogation that has the advantages of fast response speed and suitability for dynamic measurement. To build a low loss, wideband jammed-array wideband sawtooth (JAWS) filter, a finite reflection virtually imaged array (FRVIA) is proposed and demonstrated. FRVIA is different from the virtually imaged phased array in that it has a low reflective front end. This change will lead to many differences in the device's performance in output optical intensity distribution, spectral resolution, output aperture, and tolerance of the manufacture errors. A low loss, wideband JAWS filter based on an FRVIA can provide an edge filter for each channel, respectively.

Self-Organized Criticality and Scaling in Lifetime of Traffic Jams

NASA Astrophysics Data System (ADS)

Nagatani, Takashi

1995-01-01

The deterministic cellular automaton 184 (the one-dimensional asymmetric simple-exclusion model with parallel dynamics) is extended to take into account injection or extraction of particles. The model presents the traffic flow on a highway with inflow or outflow of cars.Introducing injection or extraction of particles into the asymmetric simple-exclusion model drives the system asymptotically into a steady state exhibiting a self-organized criticality. The typical lifetime of traffic jams scales as \\cong Lν with ν=0.65±0.04. It is shown that the cumulative distribution Nm (L) of lifetimes satisfies the finite-size scaling form Nm (L) \\cong L-1 f(m/Lν).

Totally asymmetric simple exclusion process with entrance rate sin(x)

NASA Astrophysics Data System (ADS)

Liang, Yifan; Chen, Xiaoyu; Liu, Yanna; Xiao, Song

2017-03-01

In recently, traffic jams have become the focus and one used different approaches to study them. In this paper, the function of sin(x) is used to simulate the enter rate α of the peak period to work. The mean field approach has been used to calculate the phase diagrams and these results were compared with Monte Carlo simulations. They are good agreement. When traffic accidents occur at the exit, the exit rate β will be less than 1 and traffic jams will occur. Different fixed the exit rate β is used to calculate the additional energy consumption. The additional energy consumption will increase with the reducing of the exit rate β.

Mechanical Four-Pole Parameters: Transmission Matrices

DTIC Science & Technology

1976-04-19

moment of inertia, it is pcssible to state that 1, = i2 ’jV 2 (127) ~ =v 2 ,(128) B, = B2 ,(129) el e2 (130) 28 1 -JA 0 0 P2 0 1 0 0 VM 0 1 j :(. 131 ...Eq. 129 now becomes + JCI ,2(1.32) so that F1 1 -JaM 0 0 F2 V, 0 1 0 0 V2 ~ :~ (133) B. 0 0o 1 Jcn B 2 1 2 3. Spring of Stiffness K in Cascade [Fig...transmission matrix is that of Eq. 131 in which the element - JaM has been replaced py - Za. 9. VALUES OF TRANSMISSION MATRICES (BERNOULLI-EUER BEANS

Anatomy of a Jam

NASA Astrophysics Data System (ADS)

Tang, Junyao; Sagdighpour, Sepehr; Behringer, Robert

2008-11-01

Flow in a hopper is both a fertile testing ground for understanding models for granular flow and industrially highly relevant. However, the formation of arches in the hopper opening, which halts the hopper flow unpredictably, is still poorly understood. In this work, we conduct a two-dimension hopper experiments, using photoelastic particles, and characterize these experiments in terms of a statistical model that considers the probability of jamming. The distribution of the hopper flow times exhibits an exponential decay, which shows the existence of a characteristic ``mean flow time.'' We then conduct further experiments to examine the connection between the mean flow time, the hopper geometry, the local density, and geometric structures and forces at the particle scale.

Calling louder and longer: how bats use biosonar under severe acoustic interference from other bats

PubMed Central

Amichai, Eran; Blumrosen, Gaddi; Yovel, Yossi

2015-01-01

Active-sensing systems such as echolocation provide animals with distinct advantages in dark environments. For social animals, however, like many bat species, active sensing can present problems as well: when many individuals emit bio-sonar calls simultaneously, detecting and recognizing the faint echoes generated by one's own calls amid the general cacophony of the group becomes challenging. This problem is often termed ‘jamming’ and bats have been hypothesized to solve it by shifting the spectral content of their calls to decrease the overlap with the jamming signals. We tested bats’ response in situations of extreme interference, mimicking a high density of bats. We played-back bat echolocation calls from multiple speakers, to jam flying Pipistrellus kuhlii bats, simulating a naturally occurring situation of many bats flying in proximity. We examined behavioural and echolocation parameters during search phase and target approach. Under severe interference, bats emitted calls of higher intensity and longer duration, and called more often. Slight spectral shifts were observed but they did not decrease the spectral overlap with jamming signals. We also found that pre-existing inter-individual spectral differences could allow self-call recognition. Results suggest that the bats’ response aimed to increase the signal-to-noise ratio and not to avoid spectral overlap. PMID:26702045

Replication-guided nucleosome packing and nucleosome breathing expedite the formation of dense arrays

PubMed Central

Osberg, Brendan; Nuebler, Johannes; Korber, Philipp; Gerland, Ulrich

2014-01-01

The first level of genome packaging in eukaryotic cells involves the formation of dense nucleosome arrays, with DNA coverage near 90% in yeasts. How cells achieve such high coverage within a short time, e.g. after DNA replication, remains poorly understood. It is known that random sequential adsorption of impenetrable particles on a line reaches high density extremely slowly, due to a jamming phenomenon. The nucleosome-shifting action of remodeling enzymes has been proposed as a mechanism to resolve such jams. Here, we suggest two biophysical mechanisms which assist rapid filling of DNA with nucleosomes, and we quantitatively characterize these mechanisms within mathematical models. First, we show that the ‘softness’ of nucleosomes, due to nucleosome breathing and stepwise nucleosome assembly, significantly alters the filling behavior, speeding up the process relative to ‘hard’ particles with fixed, mutually exclusive DNA footprints. Second, we explore model scenarios in which the progression of the replication fork could eliminate nucleosome jamming, either by rapid filling in its wake or via memory of the parental nucleosome positions. Taken together, our results suggest that biophysical effects promote rapid nucleosome filling, making the reassembly of densely packed nucleosomes after DNA replication a simpler task for cells than was previously thought. PMID:25428353

Nature of the Congested Traffic and Quasi-steady States of the General Motor Models

NASA Astrophysics Data System (ADS)

Yang, Bo; Xu, Xihua; Pang, John Z. F.; Monterola, Christopher

2015-03-01

We look at the general motor (GM) class microscopic traffic models and analyze some of the universal features of the (multi-)cluster solutions, including the emergence of an intrinsic scale and the quasisoliton dynamics. We show that the GM models can capture the essential physics of the real traffic dynamics, especially the phase transition from the free flow to the congested phase, from which the wide moving jams emerges (the F-S-J transition pioneered by B.S. Kerner). In particular, the congested phase can be associated with either the multi-cluster quasi-steady states, or their more homogeneous precursor states. In both cases the states can last for a long time, and the narrow clusters will eventually grow and merge, leading to the formation of the wide moving jams. We present a general method to fit the empirical parameters so that both quantitative and qualitative macroscopic empirical features can be reproduced with a minimal GM model. We present numerical results for the traffic dynamics both with and without the bottleneck, including various types of spontaneous and induced ``synchronized flow,'' as well as the evolution of wide moving jams. We also discuss its implications to the nature of different phases in traffic dynamics.

Motility-Driven Glass and Jamming Transitions in Biological Tissues

NASA Astrophysics Data System (ADS)

Bi, Dapeng; Yang, Xingbo; Marchetti, M. Cristina; Manning, M. Lisa

2016-04-01

Cell motion inside dense tissues governs many biological processes, including embryonic development and cancer metastasis, and recent experiments suggest that these tissues exhibit collective glassy behavior. To make quantitative predictions about glass transitions in tissues, we study a self-propelled Voronoi model that simultaneously captures polarized cell motility and multibody cell-cell interactions in a confluent tissue, where there are no gaps between cells. We demonstrate that the model exhibits a jamming transition from a solidlike state to a fluidlike state that is controlled by three parameters: the single-cell motile speed, the persistence time of single-cell tracks, and a target shape index that characterizes the competition between cell-cell adhesion and cortical tension. In contrast to traditional particulate glasses, we are able to identify an experimentally accessible structural order parameter that specifies the entire jamming surface as a function of model parameters. We demonstrate that a continuum soft glassy rheology model precisely captures this transition in the limit of small persistence times and explain how it fails in the limit of large persistence times. These results provide a framework for understanding the collective solid-to-liquid transitions that have been observed in embryonic development and cancer progression, which may be associated with epithelial-to-mesenchymal transition in these tissues.

CYBERWAR-2012/13: Siegel 2011 Predicted Cyberwar Via ACHILLES-HEEL DIGITS BEQS BEC ZERO-DIGIT BEC of/in ACHILLES-HEEL DIGITS Log-Law Algebraic-Inversion to ONLY BEQS BEC Digit-Physics U Barabasi Network/Graph-Physics BEQS BEC JAMMING Denial-of-Access(DOA) Attacks 2012-Instantiations

NASA Astrophysics Data System (ADS)

Huffmann, Master; Siegel, Edward Carl-Ludwig

2013-03-01

Newcomb-Benford(NeWBe)-Siegel log-law BEC Digit-Physics Network/Graph-Physics Barabasi et.al. evolving-``complex''-networks/graphs BEC JAMMING DOA attacks: Amazon(weekends: Microsoft I.E.-7/8(vs. Firefox): Memorial-day, Labor-day,...), MANY U.S.-Banks:WF,BoA,UB,UBS,...instantiations AGAIN militate for MANDATORY CONVERSION to PARALLEL ANALOG FAULT-TOLERANT but slow(er) SECURITY-ASSURANCE networks/graphs in parallel with faster ``sexy'' DIGITAL-Networks/graphs:``Cloud'', telecomm: n-G,..., because of common ACHILLES-HEEL VULNERABILITY: DIGITS!!! ``In fast-hare versus slow-tortoise race, Slow-But-Steady ALWAYS WINS!!!'' (Zeno). {Euler [#s(1732)] ∑- ∏()-Riemann[Monats. Akad. Berlin (1859)] ∑- ∏()- Kummer-Bernoulli (#s)}-Newcomb [Am.J.Math.4(1),39 (81) discovery of the QUANTUM!!!]-{Planck (01)]}-{Einstein (05)]-Poincar e [Calcul Probabilités,313(12)]-Weyl[Goett. Nach.(14); Math.Ann.77,313(16)]-(Bose (24)-Einstein(25)]-VS. -Fermi (27)-Dirac(27))-Menger [Dimensiontheorie(29)]-Benford [J.Am. Phil.Soc.78,115(38)]-Kac[Maths Stats.-Reason. (55)]- Raimi [Sci.Am.221,109(69)]-Jech-Hill [Proc.AMS,123,3,887(95)] log-function

The impacts of Phalaris arundinacea (reed canary grass) invasion on wetland plant richness in the Oregon Coast Range, USA, depend on beavers

USGS Publications Warehouse

Perkins, T.; Wilson, M.

2005-01-01

Invasive plants can threaten diversity and ecosystem function. We examined the relationship between the invasive Phalaris arundinacea (reed canarygrass) and species richness in beaver wetlands in Oregon, USA. Four basins (drainages) were chosen and three sites each of beaver impoundments, unimpounded areas and areas upstream of debris jams were randomly chosen in each basin for further study (n = 36). Analysis of covariance (ANCOVA) showed that the relationship between Phalaris and species richness differed significantly (p = 0.01) by site type. Dam sites (beaver impoundments) exhibited a strong inverse relationship between Phalaris and species richness (bD = a??0.15), with one species lost for each 7% increase in Phalaris cover. In contrast, there was essentially no relationship between Phalaris cover and species richness in jam sites (debris jam impoundments formed by flooding; bJ = +0.01) and unimpounded sites (bU = a??0.03). The cycle of beaver impoundment and abandonment both disrupts the native community and provides an ideal environment for Phalaris, which once established tends to exclude development of herbaceous communities and limits species richness. Because beaver wetlands are a dominant wetland type in the Coast Range, Phalaris invasion presents a real threat to landscape heterogeneity and ecosystem function in the region.

a Numerical Investigation of the Jamming Transition in Traffic Flow on Diluted Planar Networks

NASA Astrophysics Data System (ADS)

Achler, Gabriele; Barra, Adriano

In order to develop a toy model for car's traffic in cities, in this paper we analyze, by means of numerical simulations, the transition among fluid regimes and a congested jammed phase of the flow of kinetically constrained hard spheres in planar random networks similar to urban roads. In order to explore as timescales as possible, at a microscopic level we implement an event driven dynamics as the infinite time limit of a class of already existing model (Follow the Leader) on an Erdos-Renyi two-dimensional graph, the crossroads being accounted by standard Kirchoff density conservations. We define a dynamical order parameter as the ratio among the moving spheres versus the total number and by varying two control parameters (density of the spheres and coordination number of the network) we study the phase transition. At a mesoscopic level it respects an, again suitable, adapted version of the Lighthill-Whitham model, which belongs to the fluid-dynamical approach to the problem. At a macroscopic level, the model seems to display a continuous transition from a fluid phase to a jammed phase when varying the density of the spheres (the amount of cars in a city-like scenario) and a discontinuous jump when varying the connectivity of the underlying network.

Effect of psychological tension on pedestrian counter flow via an extended cost potential field cellular automaton model

NASA Astrophysics Data System (ADS)

Li, Xingli; Guo, Fang; Kuang, Hua; Zhou, Huaguo

2017-12-01

Psychology tells us that the different level of tension may lead to different behavior variation for individuals. In this paper, an extended cost potential field cellular automaton is proposed to simulate pedestrian counter flow under an emergency by considering behavior variation of pedestrian induced by psychological tension. A quantitative formula is introduced to describe behavioral changes caused by psychological tension, which also leads to the increasing cost of discomfort. The numerical simulations are performed under the periodic boundary condition and show that the presented model can capture some essential features of pedestrian counter flow, such as lane formation and segregation phenomenon for normal condition. Furthermore, an interesting feature is found that when pedestrians are in an extremely nervous state, a stable lane formation will be broken by a disordered mixture flow. The psychological nervousness under an emergency is not always negative to moving efficiency and a moderate level of tension will delay the occurrence of jamming phase. In addition, a larger asymmetrical ratio of left walkers to right walkers will improve the critical density related to the jamming phase and retard the occurrence of completely jammed phase. These findings will be helpful in pedestrian control and management under an emergency.

Flow and Jamming of Granular Materials in a Two-dimensional Hopper

NASA Astrophysics Data System (ADS)

Tang, Junyao

Flow in a hopper is both a fertile testing ground for understanding fundamental granular flow rheology and industrially highly relevant. Despite increasing research efforts in this area, a comprehensive physical theory is still lacking for both jamming and flow of granular materials in a hopper. In this work, I have designed a two dimensional (2D) hopper experiment using photoelastic particles (particles' shape: disk or ellipse), with the goal to build a bridge between macroscopic phenomenon of hopper flow and microscopic particle-scale dynamics. Through synchronized data of particle tracking and stress distributions in particles, I have shown differences between my data of the time-averaged velocity/stress profile of 2D hopper flow with previous theoretical predictions. I have also demonstrated the importance of a mechanical stable arch near the opening on controlling hopper flow rheology and suggested a heuristic phase diagram for the hopper flow/jamming transition. Another part of this thesis work is focused on studying the impact of particle shape of particles on hopper flow. By comparing particle-tracking and photoelastic data for ellipses and disks at the appropriate length scale, I have demonstrated an important role for the rotational freedom of elliptical particles in controlling flow rheology through particle tracking and stress analysis. This work has been supported by International Fine Particle Research Institute (IFPRI) .

A Classroom-Based Physical Activity Intervention for Urban Kindergarten and First-Grade Students: A Feasibility Study

PubMed Central

Wylie-Rosett, Judith; Kim, Mimi; Ozuah, Philip O.

2015-01-01

Abstract Background: Urban elementary schools in minority communities with high obesity prevalence may have limited resources for physical education (PE) to achieve daily activity recommendations. Little is known whether integrating physical activity (PA) into classrooms can increase activity levels of students attending such schools. Methods: We conducted a cluster randomized, controlled trial among kindergarten and first-grade students from four Bronx, New York, schools to determine feasibility and impact of a classroom-based intervention on students' PA levels. Students in two intervention schools received the Children's Hospital at Montefiore Joining Academics and Movement (CHAM JAM), an audio CD consisting of 10-minute, education-focused aerobic activities led by teachers three times a day. PA was objectively measured by pedometer. Each subject wore a sealed pedometer during the 6-hour school day for 5 consecutive days at baseline (Time 1) and 8 weeks postintervention (Time 2). Hierarchical linear models were fit to evaluate differences in mean number of steps between the two groups. Results: A total of 988 students participated (intervention group, n=500; control group, n=488). There was no significant difference at baseline between the two groups on mean number of steps (2581 [standard deviation (SD), 1284] vs. 2476 [SD, 1180]; P=0.71). Eight weeks post–CHAM JAM, intervention group students took significantly greater mean number of steps than controls (2839 [SD, 1262] vs. 2545 [SD, 1153]; P=0.0048) after adjusting for baseline number of steps and other covariates (grade, gender, recess, and PE class). CHAM JAM was equally effective in gender, grade level, and BMI subgroups. Conclusions: CHAM JAM significantly increased school-based PA among kindergarten and first-grade students in inner-city schools. This approach holds promise as a cost-effective means to integrate the physical and cognitive benefits of PA into high-risk schools. PMID:25747719

miR-145-dependent targeting of junctional adhesion molecule A and modulation of fascin expression are associated with reduced breast cancer cell motility and invasiveness.

PubMed

Götte, M; Mohr, C; Koo, C-Y; Stock, C; Vaske, A-K; Viola, M; Ibrahim, S A; Peddibhotla, S; Teng, Y H-F; Low, J-Y; Ebnet, K; Kiesel, L; Yip, G W

2010-12-16

Micro RNAs are small non-coding RNAs, which regulate fundamental cellular and developmental processes at the transcriptional and translational level. In breast cancer, miR-145 expression is downregulated compared with healthy control tissue. As several predicted targets of miR-145 potentially regulate cell motility, we aimed at investigating a potential role for miR-145 in breast cancer cell motility and invasiveness. Assisted by Affymetrix array technology, we demonstrate that overexpression of miR-145 in MDA-MB-231, MCF-7, MDA-MB-468 and SK-BR-3 breast cancer cells and in Ishikawa endometrial carcinoma cells leads to a downregulation of the cell-cell adhesion protein JAM-A and of the actin bundling protein fascin. Moreover, podocalyxin and Serpin E1 mRNA levels were downregulated, and gamma-actin, transgelin and MYL9 were upregulated upon miR-145 overexpression. These miR-145-dependent expression changes drastically decreased cancer cell motility, as revealed by time-lapse video microscopy, scratch wound closure assays and matrigel invasion assays. Immunofluorescence microscopy demonstrated restructuring of the actin cytoskeleton and a change in cell morphology by miR-145 overexpression, resulting in a more cortical actin distribution, and reduced actin stress fiber and filopodia formation. Nuclear rotation was observed in 10% of the pre-miR-145 transfected MDA-MB-231 cells, accompanied by a reduction of perinuclear actin. Luciferase activation assays confirmed direct miR-145-dependent regulation of the 3'UTR of JAM-A, whereas siRNA-mediated knockdown of JAM-A expression resulted in decreased motility and invasiveness of MDA-MB-231 and MCF-7 breast cancer cells. Our data identify JAM-A and fascin as novel targets of miR-145, firmly establishing a role for miR-145 in modulating breast cancer cell motility. Our data provide a rationale for future miR-145-targeted approaches of antimetastatic cancer therapy.

Mars Science Laboratory Rover Integrated Pump Assembly Bellows Jamming Failure

NASA Technical Reports Server (NTRS)

Johnson, Michael R.; Johnson, Joel; Birur, Gajanana; Bhandari, Pradeep; Karlmann, Paul

2012-01-01

The Mars Science Laboratory rover and spacecraft utilize two mechanically pumped fluid loops for heat transfer to and from the internal electronics assemblies and the Radioisotope Thermo-Electric Generator (RTG). The heat transfer fluid is Freon R-11 (CFC-11) which has a large coefficient of thermal expansion. The Freon within the heat transfer system must have a volume for safe expansion of the fluid as the system temperature rises. The device used for this function is a gas-over-liquid accumulator. The accumulator uses a metal bellows to separate the fluid and gas sections. During expansion and contraction of the fluid in the system, the bellows extends and retracts to provide the needed volume change. During final testing of a spare unit, the bellows would not extend the full distance required to provide the needed expansion volume. Increasing the fluid pressure did not loosen the jammed bellows either. No amount of stroking the bellows back and forth would get it to pass the jamming point. This type of failure, if it occurred during flight, would result in significant overpressure of the heat transfer system leading to a burst failure at some point in the system piping. A loss of the Freon fluid would soon result in a loss of the mission. The determination of the source of the jamming of the bellows was quite elusive, leading to an extensive series of tests and analyses. The testing and analyses did indicate the root cause of the failure, qualitatively. The results did not provide a set of dimensional limits for the existing hardware design that would guarantee proper operation of the accumulator. In the end, a new design was developed that relied on good engineering judgment combined with the test results to select a reliable enough solution that still met other physical constraints of the hardware, the schedule, and the rover system.

The edge detection method of the infrared imagery of the laser spot

NASA Astrophysics Data System (ADS)

Che, Jinxi; Zhang, Jinchun; Li, Zhongmin

2016-01-01

In the jamming effectiveness experiments, in which the thermal infrared imager was interfered by the CO2 Laser, in order to evaluate the jamming effect of the thermal infrared imager by the CO2 Laser, it was needed to analyses the obtained infrared imagery of laser spot. Because the laser spot pictures obtained from the thermal infrared imager are irregular, the edge detection is an important process. The image edge is one of the most basic characteristics of the image, and it contains most of the information of the image. Generally, because of the thermal balance effect, the partly temperature of objective is no quite difference; therefore the infrared imagery's ability of reflecting the local detail of object is obvious week. At the same time, when the information of heat distribution of the thermal imagery was combined with the basic information of target, such as the object size, the relative position of field of view, shape and outline, and so on, the information just has more value. Hence, it is an important step for making image processing to extract the objective edge of the infrared imagery. Meanwhile it is an important part of image processing procedure and it is the premise of many subsequent processing. So as to extract outline information of the target from the original thermal imagery, and overcome the disadvantage, such as the low image contrast of the image and serious noise interference, and so on, the edge of thermal imagery needs detecting and processing. The principles of the Roberts, Sobel, Prewitt and Canny operator were analyzed, and then they were used to making edge detection on the thermal imageries of laser spot, which were obtained from the jamming effect experiments of CO2 laser jamming the thermal infrared imager. On the basis of the detection result, their performances were compared. At the end, the characteristics of the operators were summarized, which provide reference for the choice of edge detection operators in thermal imagery processing in future.

Collective dynamics of soft active particles

NASA Astrophysics Data System (ADS)

van Drongelen, Ruben; Pal, Anshuman; Goodrich, Carl P.; Idema, Timon

2015-03-01

We present a model of soft active particles that leads to a rich array of collective behavior found also in dense biological swarms of bacteria and other unicellular organisms. Our model uses only local interactions, such as Vicsek-type nearest-neighbor alignment, short-range repulsion, and a local boundary term. Changing the relative strength of these interactions leads to migrating swarms, rotating swarms, and jammed swarms, as well as swarms that exhibit run-and-tumble motion, alternating between migration and either rotating or jammed states. Interestingly, although a migrating swarm moves slower than an individual particle, the diffusion constant can be up to three orders of magnitude larger, suggesting that collective motion can be highly advantageous, for example, when searching for food.

Motion of Knots in DNA Stretched by Elongational Fields

NASA Astrophysics Data System (ADS)

Klotz, Alexander R.; Soh, Beatrice W.; Doyle, Patrick S.

2018-05-01

Knots in DNA occur in biological systems, serve as a model system for polymer entanglement, and affect the efficacy of modern genomics technologies. We study the motion of complex knots in DNA by stretching molecules with a divergent electric field that provides an elongational force. We demonstrate that the motion of knots is nonisotropic and driven towards the closest end of the molecule. We show for the first time experimentally that knots can go from a mobile to a jammed state by varying an applied strain rate, and that this jamming is reversible. We measure the mobility of knots as a function of strain rate, demonstrating the conditions under which knots can be driven towards the ends of the molecule and untied.

Jammed Limit of Bijel Structure Formation

DOE PAGES

Welch, P. M.; Lee, M. N.; Parra-Vasquez, A. N. G.; ...

2017-11-02

Over the past decade, methods to control microstructure in heterogeneous mixtures by arresting spinodal decomposition via the addition of colloidal particles have led to an entirely new class of bicontinuous materials known as bijels. We present a new model for the development of these materials that yields to both numerical and analytical evaluation. This model reveals that a single dimensionless parameter that captures both chemical and environmental variables dictates the dynamics and ultimate structure formed in bijels. We also demonstrate that this parameter must fall within a fixed range in order for jamming to occur during spinodal decomposition, as wellmore » as show that known experimental trends for the characteristic domain sizes and time scales for formation are recovered by this model.« less

Dissipation and Rheology of Sheared Soft-Core Frictionless Disks Below Jamming

NASA Astrophysics Data System (ADS)

Vâgberg, Daniel; Olsson, Peter; Teitel, S.

2014-05-01

We use numerical simulations to investigate the effect that different models of energy dissipation have on the rheology of soft-core frictionless disks, below jamming in two dimensions. We find that it is not necessarily the mass of the particles that determines whether a system has Bagnoldian or Newtonian rheology, but rather the presence or absence of large connected clusters of particles. We demonstrate the key role that tangential dissipation plays in the formation of such clusters and in several models find a transition from Bagnoldian to Newtonian rheology as the packing fraction ϕ is varied. For each model, we show that appropriately scaled rheology curves approach a well defined limit as the mass of the particles decreases and collisions become strongly inelastic.

Dynamics and yielding of binary self-suspended nanoparticle fluids

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

Agrawal, Akanksha; Yu, Hsiu-Yu; Srivastava, Samanvaya

Yielding and flow transitions in bi-disperse suspensions of particles are studied using a model system comprised of self-suspended spherical nanoparticles. An important feature of the materials is that the nanoparticles are uniformly dispersed in the absence of a solvent. Addition of larger particles to a suspension of smaller ones is found to soften the suspensions, and in the limit of large size disparities, completely fluidizes the material. We show that these behaviors coincide with a speeding-up of de-correlation dynamics of all particles in the suspensions and are accompanied by a reduction in the energy dissipated at the yielding transition. Wemore » discuss our findings in terms of ligand-mediated jamming and un-jamming of hairy particle suspensions.« less

Clogging and jamming transitions in periodic obstacle arrays

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

Nguyen, Hong; Reichhardt, Charles; Olson Reichhardt, Cynthia Jane

2017-03-29

We numerically examine clogging transitions for bidisperse disks flowing through a two-dimensional periodic obstacle array. Here, we show that clogging is a probabilistic event that occurs through a transition from a homogeneous flowing state to a heterogeneous or phase-separated jammed state where the disks form dense connected clusters. The probability for clogging to occur during a fixed time increases with increasing particle packing and obstacle number. For driving at different angles with respect to the symmetry direction of the obstacle array, we show that certain directions have a higher clogging susceptibility. It is also possible to have a size-specific cloggingmore » transition in which one disk size becomes completely immobile while the other disk size continues to flow.« less

Classical-quantum arbitrarily varying wiretap channel: Secret message transmission under jamming attacks

NASA Astrophysics Data System (ADS)

Boche, Holger; Cai, Minglai; Deppe, Christian; Nötzel, Janis

2017-10-01

We analyze arbitrarily varying classical-quantum wiretap channels. These channels are subject to two attacks at the same time: one passive (eavesdropping) and one active (jamming). We elaborate on our previous studies [H. Boche et al., Quantum Inf. Process. 15(11), 4853-4895 (2016) and H. Boche et al., Quantum Inf. Process. 16(1), 1-48 (2016)] by introducing a reduced class of allowable codes that fulfills a more stringent secrecy requirement than earlier definitions. In addition, we prove that non-symmetrizability of the legal link is sufficient for equality of the deterministic and the common randomness assisted secrecy capacities. Finally, we focus on analytic properties of both secrecy capacities: We completely characterize their discontinuity points and their super-activation properties.

Traffic jam dynamics in stochastic cellular automata

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

Nagel, K.; Schreckenberg, M.

1995-09-01

Simple models for particles hopping on a grid (cellular automata) are used to simulate (single lane) traffic flow. Despite their simplicity, these models are astonishingly realistic in reproducing start-stop-waves and realistic fundamental diagrams. One can use these models to investigate traffic phenomena near maximum flow. A so-called phase transition at average maximum flow is visible in the life-times of jams. The resulting dynamic picture is consistent with recent fluid-dynamical results by Kuehne/Kerner/Konhaeuser, and with Treiterer`s hysteresis description. This places CA models between car-following models and fluid-dynamical models for traffic flow. CA models are tested in projects in Los Alamos (USA)more » and in NRW (Germany) for large scale microsimulations of network traffic.« less

A dynamic jamming point for shear thickening suspensions

NASA Astrophysics Data System (ADS)

Brown, Eric; Jaeger, Heinrich

2008-11-01

Densely packed suspensions can shear thicken, in which the viscosity increases with shear rate. We performed rheometry measurements on two model systems: corn starch in water and glass spheres in oils. In both systems we observed shear thickening up to a critical packing fraction φc (=0.55 for spherical grains) above which the flow abruptly transitions to shear thinning. The viscosity and yield stress diverge as power laws at φc. Extrapolating the dynamic ranges of shear rate and stress in the shear thickening regime up to φc suggests a finite change in shear stress with zero change in shear rate. This is a dynamic analog to the jamming point with a yield stress at zero shear rate.

Unjamming a granular hopper by vibration

NASA Astrophysics Data System (ADS)

Janda, A.; Maza, D.; Garcimartín, A.; Kolb, E.; Lanuza, J.; Clément, E.

2009-07-01

We present an experimental study of the outflow of a hopper continuously vibrated by a piezoelectric device. Outpouring of grains can be achieved for apertures much below the usual jamming limit observed for non-vibrated hoppers. Granular flow persists down to the physical limit of one grain diameter, a limit reached for a finite vibration amplitude. For the smaller orifices, we observe an intermittent regime characterized by alternated periods of flow and blockage. Vibrations do not significantly modify the flow rates both in the continuous and the intermittent regime. The analysis of the statistical features of the flowing regime shows that the flow time significantly increases with the vibration amplitude. However, at low vibration amplitude and small orifice sizes, the jamming time distribution displays an anomalous statistics.

Whole arm manipulation planning based on feedback velocity fields and sampling-based techniques.

PubMed

Talaei, B; Abdollahi, F; Talebi, H A; Omidi Karkani, E

2013-09-01

Changing the configuration of a cooperative whole arm manipulator is not easy while enclosing an object. This difficulty is mainly because of risk of jamming caused by kinematic constraints. To reduce this risk, this paper proposes a feedback manipulation planning algorithm that takes grasp kinematics into account. The idea is based on a vector field that imposes perturbation in object motion inducing directions when the movement is considerably along manipulator redundant directions. Obstacle avoidance problem is then considered by combining the algorithm with sampling-based techniques. As experimental results confirm, the proposed algorithm is effective in avoiding jamming as well as obstacles for a 6-DOF dual arm whole arm manipulator. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

An extended car-following model considering the acceleration derivative in some typical traffic environments

NASA Astrophysics Data System (ADS)

Zhou, Tong; Chen, Dong; Liu, Weining

2018-03-01

Based on the full velocity difference and acceleration car-following model, an extended car-following model is proposed by considering the vehicle’s acceleration derivative. The stability condition is given by applying the control theory. Considering some typical traffic environments, the results of theoretical analysis and numerical simulation show the extended model has a more actual acceleration of string vehicles than that of the previous models in starting process, stopping process and sudden brake. Meanwhile, the traffic jams more easily occur when the coefficient of vehicle’s acceleration derivative increases, which is presented by space-time evolution. The results confirm that the vehicle’s acceleration derivative plays an important role in the traffic jamming transition and the evolution of traffic congestion.

Soliton and kink jams in traffic flow with open boundaries.

PubMed

Muramatsu, M; Nagatani, T

1999-07-01

Soliton density wave is investigated numerically and analytically in the optimal velocity model (a car-following model) of a one-dimensional traffic flow with open boundaries. Soliton density wave is distinguished from the kink density wave. It is shown that the soliton density wave appears only at the threshold of occurrence of traffic jams. The Korteweg-de Vries (KdV) equation is derived from the optimal velocity model by the use of the nonlinear analysis. It is found that the traffic soliton appears only near the neutral stability line. The soliton solution is analytically obtained from the perturbed KdV equation. It is shown that the soliton solution obtained from the nonlinear analysis is consistent with that of the numerical simulation.

[Research on lateral shearing interferometer for field monitoring of natural gas pipeline leak].

PubMed

Zhang, Xue-Feng; Gao, Yu-Bin

2012-09-01

Aimed at the mechanical scanning spectroscopy equipment with poor anti-interference and anti-jamming ability, which affects the accuracy of its natural gas pipeline leak detection in the wild, a new type of lateral shearing interferometer system was designed. The system uses a beam splitter to get optical path difference by a mechanical scanning part, and it cancel the introduction of external vibration interference through the linkage between the two beam splitterw. The interference intensity of interference fringes produced was calculated, and analysis of a rotating beam splitter corresponds to the angle of the optical path difference function, solving for the maximum angle of the forward rotation and reverse rotation, which is the maximum optical path range. Experiments using the gas tank deflated simulated natural gas pipeline leak process, in the interference conditions, and the test data of the type WQF530 spectrometer and the new type of lateral shearing interferometer system were comparedt. The experimental results show that the relative error of both systems is about 1% in indoor conditions without interference. However, in interference environment, the error of WQF530 type spectrometer becomes larger, more than 10%, but the error of the new type of lateral shearing interferometer system is still below 5%. The detection accuracy of the type WQF530 spectrometer decreased significantly due to the environment. Therefore, the seismic design of the system can effectively offset power deviation and half-width increases of center wavelength caused by external interference, and compared to conventional mechanical scanning interferometer devices the new system is more suitable for field detection.

Possible involvement of gap junctions in the barrier function of tight junctions of brain and lung endothelial cells.

PubMed

Nagasawa, Kunihiko; Chiba, Hideki; Fujita, Hiroki; Kojima, Takashi; Saito, Tsuyoshi; Endo, Toshiaki; Sawada, Norimasa

2006-07-01

Gap-junction plaques are often observed with tight-junction strands of vascular endothelial cells but the molecular interaction and functional relationships between these two junctions remain obscure. We herein show that gap-junction proteins connexin40 (Cx40) and Cx43 are colocalized and coprecipitated with tight-junction molecules occludin, claudin-5, and ZO-1 in porcine blood-brain barrier (BBB) endothelial cells. Gap junction blockers 18beta-glycyrrhetinic acid (18beta-GA) and oleamide (OA) did not influence expression of Cx40, Cx43, occludin, claudin-5, junctional adhesion molecule (JAM)-A, JAM-B, JAM-C, or ZO-1, or their subcellular localization in the porcine BBB endothelial cells. In contrast, these gap-junction blocking agents inhibited the barrier function of tight junctions in cells, determined by measurement of transendothelial electrical resistance and paracellular flux of mannitol and inulin. 18beta-GA also significantly reduced the barrier property in rat lung endothelial (RLE) cells expressing doxycycline-induced claudin-1, but did not change the interaction between Cx43 and either claudin-1 or ZO-1, nor their expression levels or subcellular distribution. These findings suggest that Cx40- and/or Cx43-based gap junctions might be required to maintain the endothelial barrier function without altering the expression and localization of the tight-junction components analyzed. Copyright 2006 Wiley-Liss, Inc.

Nonstandard convergence to jamming in random sequential adsorption: The case of patterned one-dimensional substrates

NASA Astrophysics Data System (ADS)

Verma, Arjun; Privman, Vladimir

2018-02-01

We study approach to the large-time jammed state of the deposited particles in the model of random sequential adsorption. The convergence laws are usually derived from the argument of Pomeau which includes the assumption of the dominance, at large enough times, of small landing regions into each of which only a single particle can be deposited without overlapping earlier deposited particles and which, after a certain time are no longer created by depositions in larger gaps. The second assumption has been that the size distribution of gaps open for particle-center landing in this large-time small-gaps regime is finite in the limit of zero gap size. We report numerical Monte Carlo studies of a recently introduced model of random sequential adsorption on patterned one-dimensional substrates that suggest that the second assumption must be generalized. We argue that a region exists in the parameter space of the studied model in which the gap-size distribution in the Pomeau large-time regime actually linearly vanishes at zero gap sizes. In another region, the distribution develops a threshold property, i.e., there are no small gaps below a certain gap size. We discuss the implications of these findings for new asymptotic power-law and exponential-modified-by-a-power-law convergences to jamming in irreversible one-dimensional deposition.

Influence of Images on the Evaluation of Jams Using Conjoint Analysis Combined with Check-All-That-Apply (CATA) Questions.

PubMed

Miraballes, Marcelo; Gámbaro, Adriana

2018-01-01

A study of the influence of the use of images in a conjoint analysis combined with check-all-that apply (CATA) questions on jams was carried out. The relative importance of flavor and the information presented in the label in the willingness to purchase and the perception of how healthy the product is has been evaluated. Sixty consumers evaluated the stimuli presented only in text format (session 1), and another group of 60 consumers did so by receiving the stimuli in text format along with an image of the product (session 2). In addition, for each stimulus, consumers answered a CATA question consisting of 20 terms related to their involvement with the product. The perception of healthy increased when the texts were accompanied with images and also increased when the text included information. Willingness to purchase was only influenced by the flavor of the jams. The presence of images did not influence the CATA question's choice of terms, which were influenced by the information presented in the text. The use of a check-all-that-apply question in concepts provided an interesting possibility when they were combined with the results from the conjoint analysis, improving the comprehension of consumers' perception. Using CATA questions as an alternative way of evaluating consumer involvement seems to be beneficial and should be evaluated much further. © 2017 Institute of Food Technologists®.

Longitudinal distribution and parameters of large wood in a Mediterranean ephemeral stream

NASA Astrophysics Data System (ADS)

Galia, T.; Škarpich, V.; Tichavský, R.; Vardakas, L.; Šilhán, K.

2018-06-01

Although large wood (LW) has been intensively studied in forested basins of humid temperate climates, data on LW patterns in different fluvial environments are rather scarce. Therefore, we investigated the dimensions, characteristics, longitudinal distribution, and dynamics of LW along a 4.05-km-long reach of an ephemeral channel typical of European Mediterranean mountainous landscape (Sfakiano Gorge, Crete, Greece). We analysed a total of 795 LW pieces, and the mean observed abundance of LW was generally lower (14.3 m3/ha of active valley floor or 19.6 LW pieces/100 m of stream length) than is usually documented for more humid environments. The number of LW pieces was primarily controlled by trees growing on the valley floor. These living trees acted as important LW supply agents (by tree throws or the supply of individual branches with sufficient LW dimensions) and flow obstructions during large flood events, causing storage of transported LW pieces in jams. However, the downstream transport of LW is probably episodic, and large jams are likely formed only during major floods; after >15 years, we still observed significant imprints of the last major flood event on the present distribution of LW. The geomorphic function of LW in the studied stream can only be perceived to be a spatially limited stabilising element for sediments, which was documented by a few accumulations of coarse clastic material by LW steps and jams.

JAM-A and ALCAM are therapeutic targets to inhibit diapedesis across the BBB of CD14+CD16+ monocytes in HIV-infected individuals.

PubMed

Williams, Dionna W; Anastos, Kathryn; Morgello, Susan; Berman, Joan W

2015-02-01

Monocyte transmigration across the BBB is a critical step in the development of cognitive deficits termed HAND that affect 40-70% of HIV-infected individuals, even with successful antiretroviral therapy. The monocyte subsets that enter the CNS during HIV infection are not fully characterized. We examined PBMC from HIV-positive individuals from 2 distinct cohorts and enumerated monocyte populations, characterized their transmigration properties across an in vitro human BBB model, and identified surface proteins critical for the entry of these cells into the CNS. We demonstrated that the frequency of peripheral blood CD14(+)CD16(+) and CD14(low)CD16(+) monocytes was increased in HIV-seropositive compared with -seronegative individuals, despite virologic control. We showed that CD14(+)CD16(+) monocytes selectively transmigrated across our BBB model as a result of their increased JAM-A and ALCAM expression. Antibody blocking of these proteins inhibited diapedesis of CD14(+)CD16(+) monocytes but not of T cells from the same HIV-infected people across the BBB. Our data indicate that JAM-A and ALCAM are therapeutic targets to decrease the entry of CD14(+)CD16(+) monocytes into the CNS of HIV-seropositive individuals, contributing to the eradication of neuroinflammation, HAND, and CNS viral reservoirs. © Society for Leukocyte Biology.

Reconfiguration of a flexible fiber immersed in a 2D dense granular flow close to the jamming transition

NASA Astrophysics Data System (ADS)

Kolb, Evelyne; Algarra, Nicolas; Vandembroucq, Damien; Lazarus, Arnaud

2015-11-01

We propose a new fluid/structure interaction in the unusual case of a dense granular medium flowing against an elastic fibre acting as a flexible intruder. We experimentally studied the deflection of a mylar flexible beam clamped at one side, the other free side facing a 2D granular flow in a horizontal cell moving at a constant velocity. We investigated the reconfiguration of the fibre as a function of the fibre's rigidity and of the granular packing fraction close but below the jamming in 2D. Imposing the fibre geometry like its length or thickness sets the critical buckling force the fibre is able to resist if it was not supported by lateral grains, while increasing the granular packing fraction might laterally consolidate the fibre and prevent it from buckling. But on the other side, the approach to jamming transition by increasing the granular packing fraction will be characterized by a dramatically increasing size of the cluster of connected grains forming a solid block acting against the fibre, which might promote the fibre's deflection. Thus, we investigated the granular flow fields, the fibre's deflexion as well as the forces experienced by the fibre and compared them with theoretical predictions from elastica for different loadings along the fibre. PMMH, CNRS UMR 7636, UPMC, ESPCI-ParisTech, 10 rue Vauquelin, 75231 Paris Cedex 05, France.

Sensuality test result for application to space foods of the disaster food

NASA Astrophysics Data System (ADS)

Katayama, Naomi; Okano, Yukimi; Kondou, Syouko

2016-07-01

The human became able to stay in the space for a long term. This is very important to step forward to the first step for Mars emigration. The long-term stay in the space has a big great stress. The space foods are important to keep a body and mind from those stress. The maintenance of the function of the astronaut of immunity and a meal for the hormone to keep the balance are necessary. As for both the space foods and the disaster meal, room-temperature preservation is possible for a long term. However, the taste is important to even disaster food. The person is repeated if not delicious and cannot eat disaster foods. The sensuality test result about the taste of the disaster food is important. Melon bun, Strawberry jam bun, Cream bun, Maple caramel, Bean-jam bun, Croissant, Croissant Rich, Ogura croissant, Buran croissant, Waffle, Maple waffle, Buran waffle, Strawberry milk waffle, Chocolate bun A cream bun is special. The bean-jam bun is very familiar bread for a Japanese. Because a lot of dietary fibers were good for health as for the buran croissant, an evaluation was high. We think that it is similar in the space foods. It is necessary to think about a universal meal in the space foods. We think that it is necessary to prepare the food which a person of the whole world likes.

Onset of jamming for gas-fluidized grains

NASA Astrophysics Data System (ADS)

Abate, Adam

2006-03-01

Upon approach to jamming, whether for molecular liquids or colloidal particles or grains of sand, the microscopic dynamics can develop dramatic long-ranged correlations while the microscopic structure remains relatively unchanged. Experimentally, it has been difficult to study such phenomena in full detail due to the range of temporal and spatial scales involved. Here we introduce a new model system that is both easier to image and to manipulate at the microscale: a bidisperse system of steel beads rolling stochastically due to a nearly-levitating upflow of air. At fixed air flow, we demonstrate that this system exhibits all the hallmarks of a jamming transition as spheres are added and the area fraction increases toward close-packing. In terms of structure, the pair correlation function and the Voronoi cell shape distribution functions exhibit peak splitting. In terms of dynamics, the mean-squared displacement develops a plateau separating the short-time ballistic from the long-time diffusive motions; in this plateau the displacement distribution is non-Gaussian, due to spatial heterogeneities. While this phenomenology is familiar, one feature observed previously only in simulation is the presence of string-like swirls of rearranging grains. We highlight these by movies of an appropriately time-averaged velocity field. We hope to connect such dynamics both to a microscopic measure of effective temperature and to the macroscopic viscosity of the system.

Bilberry

MedlinePlus

... diarrhea, scurvy, infections, burns, and diabetes. During World War II, British pilots ate bilberry jam, thinking it ... therapy is not an endorsement by NCCIH. U.S. Department of Health & Human Services, National Institutes of Health, ...

Aging, memory, and nonhierarchical energy landscape of spin jam

NASA Astrophysics Data System (ADS)

Samarakoon, Anjana; Sato, Taku J.; Chen, Tianran; Chern, Gai-Wei; Yang, Junjie; Klich, Israel; Sinclair, Ryan; Zhou, Haidong; Lee, Seung-Hun

2016-10-01

The notion of complex energy landscape underpins the intriguing dynamical behaviors in many complex systems ranging from polymers, to brain activity, to social networks and glass transitions. The spin glass state found in dilute magnetic alloys has been an exceptionally convenient laboratory frame for studying complex dynamics resulting from a hierarchical energy landscape with rugged funnels. Here, we show, by a bulk susceptibility and Monte Carlo simulation study, that densely populated frustrated magnets in a spin jam state exhibit much weaker memory effects than spin glasses, and the characteristic properties can be reproduced by a nonhierarchical landscape with a wide and nearly flat but rough bottom. Our results illustrate that the memory effects can be used to probe different slow dynamics of glassy materials, hence opening a window to explore their distinct energy landscapes.

CPM Signals for Satellite Navigation in the S and C Bands.

PubMed

Xue, Rui; Sun, Yanbo; Zhao, Danfeng

2015-06-05

Frequency allocations in the L band suitable for global navigation satellite system (GNSS) services are getting crowded and system providers face an ever tougher job when they try to bring in new signals and services while maintaining radio frequency compatibility. With the successive opening of the S and C bands to GNSS service, the multi-band combined navigation is predicted to become a key technology for future high-precision positioning navigation systems, and a single modulation scheme satisfying the requirements in each band is a promising solution for reducing user terminal complexity. A universal modulation scheme based on the continuous phase modulation (CPM) family suitable for the above bands' demands is proposed. Moreover, this paper has put forward two specific CPM signals for the S and C bands, respectively. Then the proposed modulation schemes, together with existing candidates, are comprehensively evaluated. Simulation results show that the proposed CPM signals can not only satisfy the constraint condition of compatibility in different bands well and reduce user terminal complexity, but also provide superior performance in terms of tracking accuracy, multi-path mitigation and anti-jamming compared to other candidate modulation schemes.

[Study on the application of pyroelectric infrared sensor to safety protection system].

PubMed

Wang, Song-de; Zhang, Shuan-ji; Zhu, Xiao-long; Yang, Jie-hui

2006-11-01

Using the infrared ray of human body, which is received and magnified by pyroelectric infrared sensor to form a certain voltage control signal, and using the control signal to trigger a voice recording-reproducing circuit, a pyroelectric infrared detector voice device with auto-control function designed. The circuit adopted new pyroelectric infrared detector assembly and voice recording-reproducing assembly. When someone is present in the detectable range of the pyroelectric infrared detector, first, the pyroelectric infrared sensor will transform the incepted radiation energy to a electric signal, which is then magnified and compared by an inside circuit, and an output control signal, touches off the voice recording-reproducing assembly with the reproducer sending out a beforehand transcribed caution voice to wise the man who does not know well the surrounding condition that the frontage is a danger zone and should not be approched. With the design of integrated structures, the distance-warning device has the advantages of strong anti-jamming ability, low temperature resistance, working stability and use-convenience, and it can be suitably installed and used in several locations which may endanger person safety, such as substation, high voltage switch panel, electric transformer, etc.

T'ai Chi

MedlinePlus

... who practice it wear a martial arts training uniform. T'ai chi is usually practiced barefoot or ... health problem. Is your schedule jam-packed with school, work, and social activities? Here are a few ...

Confined disordered strictly jammed binary sphere packings

NASA Astrophysics Data System (ADS)

Chen, D.; Torquato, S.

2015-12-01

Disordered jammed packings under confinement have received considerably less attention than their bulk counterparts and yet arise in a variety of practical situations. In this work, we study binary sphere packings that are confined between two parallel hard planes and generalize the Torquato-Jiao (TJ) sequential linear programming algorithm [Phys. Rev. E 82, 061302 (2010), 10.1103/PhysRevE.82.061302] to obtain putative maximally random jammed (MRJ) packings that are exactly isostatic with high fidelity over a large range of plane separation distances H , small to large sphere radius ratio α , and small sphere relative concentration x . We find that packing characteristics can be substantially different from their bulk analogs, which is due to what we term "confinement frustration." Rattlers in confined packings are generally more prevalent than those in their bulk counterparts. We observe that packing fraction, rattler fraction, and degree of disorder of MRJ packings generally increase with H , though exceptions exist. Discontinuities in the packing characteristics as H varies in the vicinity of certain values of H are due to associated discontinuous transitions between different jammed states. When the plane separation distance is on the order of two large-sphere diameters or less, the packings exhibit salient two-dimensional features; when the plane separation distance exceeds about 30 large-sphere diameters, the packings approach three-dimensional bulk packings. As the size contrast increases (as α decreases), the rattler fraction dramatically increases due to what we call "size-disparity" frustration. We find that at intermediate α and when x is about 0.5 (50-50 mixture), the disorder of packings is maximized, as measured by an order metric ψ that is based on the number density fluctuations in the direction perpendicular to the hard walls. We also apply the local volume-fraction variance στ2(R ) to characterize confined packings and find that these packings possess essentially the same level of hyperuniformity as their bulk counterparts. Our findings are generally relevant to confined packings that arise in biology (e.g., structural color in birds and insects) and may have implications for the creation of high-density powders and improved battery designs.

Confocal Microscopy of Jammed Matter: From Elasticity to Granular Thermodynamics

NASA Astrophysics Data System (ADS)

Jorjadze, Ivane

Packings of particles are ubiquitous in nature and are of interest not only to the scientific community but also to the food, pharmaceutical, and oil industries. In this thesis we use confocal microscopy to investigate packing geometry and stress transmission in 3D jammed particulate systems. By introducing weak depletion attraction we probe the accessible phase-space and demonstrate that a microscopic approach to jammed matter gives validity to statistical mechanics framework, which is intriguing because our particles are not thermally activated. We show that the fluctuations of the local packing parameters can be successfully captured by the recently proposed 'granocentric' model, which generates packing statistics according to simple stochastic processes. This model enables us to calculate packing entropy and granular temperature, the so-called 'compactivity', therefore, providing a basis for a statistical mechanics of granular matter. At a jamming transition point at which there are formed just enough number of contacts to guarantee the mechanical stability, theoretical arguments suggest a singularity which gives rise to the surprising scaling behavior of the elastic moduli and the microstructure, as observed in numerical simulations. Since the contact network in 3D is typically hidden from view, experimental test of the scaling law between the coordination number and the applied pressure is lacking in the literature. Our data show corrections to the linear scaling of the pressure with density which takes into account the creation of contacts. Numerical studies of vibrational spectra, in turn, reveal sudden features such as excess of low frequency modes, dependence of mode localization and structure on the pressure. Chapter four describes the first calculation of vibrational density of states from the experimental 3D data and is in qualitative agreement with the analogous computer simulations. We study the configurational role of the pressure and demonstrate that low frequency modes become progressively localized as the packing density is increased. Another application of our oil-in-water emulsions serves to mimic cell adhesion in biological tissues. By analyzing the microstructure in 3D we find that a threshold compression force is necessary to overcome electrostatic repulsion and surface elasticity and establish protein-mediated adhesion.

14 CFR 29.395 - Control system.

Code of Federal Regulations, 2013 CFR

2013-01-01

... consideration of fatigue, jamming, ground gusts, control inertia, and friction loads. In the absence of a... inertia, or friction, the system must withstand the limit pilot forces specified in § 29.397, without...

40 CFR 407.80 - Applicability; description of the canned and miscellaneous specialties subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... VEGETABLES PROCESSING POINT SOURCE CATEGORY Canned and Miscellaneous Specialties Subcategory § 407.80...: Added ingredients; baby food; corn, potato, and tortilla chips; ethnic foods; jams and jellies...

Disordered solids: In search of the perfect glass

NASA Astrophysics Data System (ADS)

Biroli, Giulio

2014-08-01

The jury's still out on how glasses and other disordered materials form. However, a new framework suggests that we can understand their mechanical properties without this information, by using the physics of jamming.

Precision powder feeder

DOEpatents

Schlienger, M. Eric; Schmale, David T.; Oliver, Michael S.

2001-07-10

A new class of precision powder feeders is disclosed. These feeders provide a precision flow of a wide range of powdered materials, while remaining robust against jamming or damage. These feeders can be precisely controlled by feedback mechanisms.

Jamming and percolation in random sequential adsorption of straight rigid rods on a two-dimensional triangular lattice

NASA Astrophysics Data System (ADS)

Perino, E. J.; Matoz-Fernandez, D. A.; Pasinetti, P. M.; Ramirez-Pastor, A. J.

2017-07-01

Monte Carlo simulations and finite-size scaling analysis have been performed to study the jamming and percolation behavior of linear k-mers (also known as rods or needles) on a two-dimensional triangular lattice of linear dimension L, considering an isotropic RSA process and periodic boundary conditions. Extensive numerical work has been done to extend previous studies to larger system sizes and longer k-mers, which enables the confirmation of a nonmonotonic size dependence of the percolation threshold and the estimation of a maximum value of k from which percolation would no longer occur. Finally, a complete analysis of critical exponents and universality has been done, showing that the percolation phase transition involved in the system is not affected, having the same universality class of the ordinary random percolation.

Force Network of a 2D Frictionless Emulsion System

NASA Astrophysics Data System (ADS)

Desmond, Kenneth; Weeks, Eric R.

2010-03-01

We use a quasi-two-dimensional emulsion as a new experimental system to measure various jamming transition properties. Our system consist of confining oil-in-water emulsion droplets between two parallel plates, so that the droplets are squeezed into quasi-two dimensional disks, analogous to granular photoelastic disks. By varying the droplet area fraction, we investigate the force network of this system as we cross through the jamming transition. At a critical area fraction, the composition of the system is no longer characterized primarily by circular disks, but by disks deformed to varying degrees. Quantifying the deformation provides information about the forces acting upon each droplet, and ultimately the force network. The probability distribution of forces is similar to that found for photoelastic disks, with the width of the force distribution narrowing with increasing packing fraction.

Dense granular flow around a rigid or flexible intruder

NASA Astrophysics Data System (ADS)

Kolb, Evelyne; Adda-Bedia, Mokhtar

2012-02-01

We experimentally studied the flow of a dense granular material around an obstacle (rigid cylinder or flexible plate) placed in a 2 dimensional confined cell at a packing fraction near the 2D jamming threshold. In the case of the rigid obstacle, the displacement field of grains as well as the drag force experienced by the obstacle were simultaneously recorded and a parametric study was done by changing the cell size, the intruder diameter or the packing fraction. The drag force experienced by the intruder and the formation of a wake behind the obstacle were very sensitive to the approach to jamming. The same experimental set-up was adapted to a flexible intruder and coupling between the granular flow and fibre deflexion were imaged. The deformation of the fibre could be compared with theoretical predictions from elastica.

Exact solution of two interacting run-and-tumble random walkers with finite tumble duration

NASA Astrophysics Data System (ADS)

Slowman, A. B.; Evans, M. R.; Blythe, R. A.

2017-09-01

We study a model of interacting run-and-tumble random walkers operating under mutual hardcore exclusion on a one-dimensional lattice with periodic boundary conditions. We incorporate a finite, poisson-distributed, tumble duration so that a particle remains stationary whilst tumbling, thus generalising the persistent random walker model. We present the exact solution for the nonequilibrium stationary state of this system in the case of two random walkers. We find this to be characterised by two lengthscales, one arising from the jamming of approaching particles, and the other from one particle moving when the other is tumbling. The first of these lengthscales vanishes in a scaling limit where the continuous-space dynamics is recovered whilst the second remains finite. Thus the nonequilibrium stationary state reveals a rich structure of attractive, jammed and extended pieces.

Automating the deconfliction of jamming and spectrum management

NASA Astrophysics Data System (ADS)

Segner, Samuel M.

1988-12-01

Powerful airborne and ground based jammers are being fielded by all services and nations as part of their intelligence/electronic warfare (I/EW) combat capability. For their survivability, these I/EW systems operate far from the FLOT; this creates rather large denial areas to friendly forces when they jam. Manual coordination between IE/W managers and spectrum managers is not practical to take on targets of opportunities or track the intended enemy victims when these victims counter by frequency maneuvers. Two possible architectures, one centralized, the other decentralized, are explored as is the applicability of the electromagnetic compatibility (EMC) software developed for the U.S. Army Automatic Tactical Frequency Engineering System (ATFES) pilot program. The proposed approach is to apply the principles of the Joint Commanders EW Staff (JCEWS). The initial simplified software to demonstrate the computer aided coordination at VHF is explained.