Patients With Limited Health Literacy Have Similar Preferences but Different Perceptions in Surgical Decision-making for Carpal Tunnel Release.

Science.gov (United States)

Roh, Young Hak; Koh, Young Do; Kim, Jong Oh; Noh, Jung Ho; Gong, Hyun Sik; Baek, Goo Hyun

2018-04-01

patients' clinical, demographic, and health literacy factors accounted for the preoperative preferences and postoperative assessments of their role in shared decision-making. A total of 133 patients would provide 94% power for a medium effect size for linear regression with five main predictors. We found no differences between patients with lower levels of health literacy and those with greater health literacy in terms of preferences of shared decision-making for carpal tunnel release (3.0 ± 1.6 versus 2.7 ± 1.4; mean difference, 0.3; 95% confidence interval, -0.2 to 0.8; p = 0.25). A history of surgical procedures (coefficient = -0.32, p decision-making. However, patients with limited health literacy (coefficient = -0.31, p = 0.01) and an absence of a caregiver (coefficient = -0.28, p = 0.03) perceived a more passive role in actual decision-making. Physicians should be aware of the discrepancy between preferences and perceptions of shared decision-making among patients with limited health literacy, and physicians should consider providing a decision aid tailored to basic levels of health literacy to help patients achieve their preferred role in decision-making. Level II, prognostic study.

[Socio professional impact of surgical release of carpal tunnel syndrome].

Science.gov (United States)

Kraiem, Aouatef Mahfoudh; Hnia, Hajer; Bouzgarrou, Lamia; Henchi, Mohamed Adnène; Khalfallah, Taoufik

2016-01-01

The objective was studying the socio-professional impact of release surgery for carpal tunnel syndrom (CTS). We conducted a cross-sectional study of patients operated for work-related CTS; data were collected in the Occupational Health Department at the University Hospital Tahar Sfar in Mahdia, Tunisia over a period of 8 years, from 1 January 2006 to December 2013. Data collection was performed using a survey form focusing on participants' socio-professional and medical characteristics and on their professional future. We used Karasek's questionnaire to study psychosocial constraints at work. The duration of a work stoppage following release surgery for CTS was significantly related to the existence of musculoskeletal disorders other than CTS, to a statement that the carpal tunnel syndrome was work related and to job seniority. As regards the professional future of operated employees, 50.7% remained in the same position, 15.3% were given customized workstation and 33.8% were offered a different position within the same company. The professional future of these employees was related to their occupational qualifications and to the type of sensory and/or motor impairment of median nerve detected during EMG test. A number of nonlesional factors determines the duration of the work stoppage, while the professional future of patients operated for CTS essentially depends on their professional qualifications and on EMG data. Certainly much broader studies would allow to refine these results.

Tunneling and reflection in unimolecular reaction kinetic energy release distributions

Science.gov (United States)

Hansen, K.

2018-02-01

The kinetic energy release distributions in unimolecular reactions is calculated with detailed balance theory, taking into account the tunneling and the reflection coefficient in three different types of transition states; (i) a saddle point corresponding to a standard RRKM-type theory, (ii) an attachment Langevin cross section, and (iii) an absorbing sphere potential at short range, without long range interactions. Corrections are significant in the one dimensional saddle point states. Very light and lightly bound absorbing systems will show measurable effects in decays from the absorbing sphere, whereas the Langevin cross section is essentially unchanged.

Evaluation of peripheral microcirculation improvement of foot after tarsal tunnel release in diabetic patients by transcutaneous oximetry.

Science.gov (United States)

Trignano, Emilio; Fallico, Nefer; Chen, Hung-Chi; Faenza, Mario; Bolognini, Alfonso; Armenti, Andrea; Santanelli Di Pompeo, Fabio; Rubino, Corrado; Campus, Gian Vittorio

2016-01-01

According to recent studies, peripheral nerve decompression in diabetic patients seems to not only improve nerve function, but also to increase microcirculation; thus decreasing the incidence of diabetic foot wounds and amputations. However, while the postoperative improvement of nerve function is demonstrated, the changes in peripheral microcirculation have not been demonstrated yet. The aim of this study is to assess the degree of microcirculation improvement of foot after the tarsal tunnel release in the diabetic patients by using transcutaneous oximetry. Twenty diabetic male patients aged between 43 and 72 years old (mean age 61.2 years old) suffering from diabetic peripheral neuropathy with superimposed nerve compression underwent transcutaneous oximetry (PtcO2) before and after tarsal tunnel release by placing an electrode on the skin at the level of the dorsum of the foot. Eight lower extremities presented diabetic foot wound preoperatively. Thirty-six lower extremities underwent surgical release of the tibialis posterior nerve only, whereas four lower extremities underwent the combined release of common peroneal nerve, anterior tibialis nerve, and posterior tibialis nerve. Preoperative values of transcutaneous oximetry were below the critical threshold, that is, lower than 40 mmHg (29.1 ± 5.4 mmHg). PtcO2 values at one month after surgery (45.8 ± 6.4 mmHg) were significantly higher than the preoperative ones (P = 0.01). The results of postoperative increase in PtcO2 values demonstrate that the release of the tarsal tunnel determines a relevant increase in microcirculation in the feet of diabetic patients. © 2015 Wiley Periodicals, Inc.

Ultrasound-Guided Carpal Tunnel Release Using Dynamic Expansion of the Transverse Safe Zone in a Patient With Postpolio Syndrome: A Case Report.

Science.gov (United States)

Henning, Troy; Lueders, Daniel; Chang, Kate; Yang, Lynda

2018-03-06

The prevalence of carpal tunnel syndrome (CTS) in patients with postpolio syndrome occurs at a rate of 22%. Irrespective of those with CTS, 74% of postpolio patients weight bear through their arms for ambulation or transfers. As open carpal tunnel release is performed along the weight-bearing region of the wrist, their functional independence may be altered while recovering. This case demonstrates that ultrasound-guided carpal tunnel release was successfully performed in a patient with postpolio syndrome allowing him to immediately weight bear through his hands after the procedure so he could recover at home. Copyright © 2018 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Effect of tunnel cross section on gas temperatures and heat fluxes in case of large heat release rate

International Nuclear Information System (INIS)

Fan, Chuan Gang; Li, Ying Zhen; Ingason, Haukur; Lönnermark, Anders

2016-01-01

Highlights: • The effect of tunnel cross section together with ventilation velocity was studied. • Ceiling temperature varies clearly with tunnel height, but little with tunnel width. • Downstream temperature decreases with increasing tunnel dimensions. • HRR is an important factor that influences decay rate of excess gas temperature. • An equation considering both tunnel dimensions and HRR was developed. - Abstract: Tests with liquid and solid fuels in model tunnels (1:20) were performed and analysed in order to study the effect of tunnel cross section (width and height) together with ventilation velocity on ceiling gas temperatures and heat fluxes. The model tunnel was 10 m long with varying width (0.3 m, 0.45 m and 0.6 m) and height (0.25 m and 0.4 m). Test results show that the maximum temperature under the ceiling is a weak function of heat release rate (HRR) and ventilation velocity for cases with HRR more than 100 MW at full scale. It clearly varies with the tunnel height and is a weak function of the tunnel width. With a lower tunnel height, the ceiling is closer to the base of continuous flame zone and the temperatures become higher. Overall, the gas temperature beneath the ceiling decreases with the increasing tunnel dimensions, and increases with the increasing longitudinal ventilation velocity. The HRR is also an important factor that influences the decay rate of excess gas temperature, and a dimensionless HRR integrating HRR and other two key parameters, tunnel cross-sectional area and distance between fuel centre and tunnel ceiling, was introduced to account for the effect. An equation for the decay rate of excess gas temperature, considering both the tunnel dimensions and HRR, was developed. Moreover, a larger tunnel cross-sectional area will lead to a smaller heat flux.

Reduction of exit-site infections of tunnelled intravascular catheters among neutropenic patients by sustained-release chlorhexidine dressings: results from a prospective randomized controlled trial.

Science.gov (United States)

Chambers, S T; Sanders, J; Patton, W N; Ganly, P; Birch, M; Crump, J A; Spearing, R L

2005-09-01

Exit-site and tunnel infections of tunnelled central intravascular catheters are a frequent source of morbidity among neutropenic patients and may necessitate catheter removal. They require antimicrobial therapy that increases healthcare costs and is associated with adverse drug reactions. A prospective randomized clinical trial was conducted among adult patients undergoing chemotherapy in a haematology unit. Tunnelled intravascular catheters were randomized to receive the control of a standard dressing regimen as recommended by the British Committee for Standards in Haematology, or to receive the intervention of a sustained-release chlorhexidine dressing. Follow-up data were available in 112 of 114 tunnelled intravascular catheters which were randomized. Exit-site or combined exit-site/tunnel infections occurred in 23 (43%) of 54 catheters in the control group, and five (9%) of 58 catheters in the intervention group [odds ratio (OR) for intervention group compared with control group =0.13, 95% confidence intervals (CI) 0.04-0.37, P<0.001]. More tunnelled intravascular catheters were prematurely removed from the control group than the intervention group for documented infections [20/54 (37%) vs 6/58 (10%), OR=0.20, 95%CI 0.53-0.07]. However, there was no difference in the numbers of tunnelled intravascular catheters removed for all proven and suspected intravascular catheter-related infections [21/54 (39%) vs 19/58 (33%)], or in the time to removal of catheters for any reason other than death or end of treatment for underlying disease. Thus chlorhexidine dressings reduced the incidence of exit-site/tunnel infections of indwelling tunnelled intravascular catheters without prolonging catheter survival in neutropenic patients, and could be considered as part of the routine management of indwelling tunnelled intravascular catheters among neutropenic patients.

A new method for calculating energy release rate in tunnel excavation subjected to high in situ stress

Directory of Open Access Journals (Sweden)

Xiao Qinghua

2016-03-01

Full Text Available Based on energy theory, energy release rate (EER and local energy release rate (LEER, a new index called FERR (Fractional Energy Release Rate is proposed, and this method can not only evaluate the risk of rock burst, but also can point out the location of high risk and the scale of rockburst. The FERR index is applied to the TBM assembling tunnel in Jinping Hydro Power Station II to evaluate the scale and intensity of rockburst, as well as the location where rockburst occurs. With FDM method adopted, the energy release rate of 3 excavation plans are calculated and the scale and risk of rockburst is evaluated, and the location of high risk of rockburst is also mapped. With FERR used in the evaluation, the rockburst is nicely controlled which ensured the safety and construction schedule of the project.

[Carpal tunnel syndrome in children. About 10 clinical cases].

Science.gov (United States)

Leduc, A; Perrot, P; Truffandier, M V; Bellier-Waast, F; Duteille, F

2014-06-01

The carpal tunnel syndrome is a common peripheral neuropathy in adults but is rare in children. We report a series of 10 carpal tunnel syndromes in children. We have supported five children, two males and three females, with a bilateral carpal tunnel syndrome. We studied the clinical history (history, symptoms, stage of disease), therapeutic management and remote development. Three children were diagnosed with a mucopolysaccharidosis, the fourth with VATER association. For the last child, it was a form considered idiopathic. Two children were referred for night pains, the others for under-utilization of their first three fingers, two of which had a thenar atrophy. Four children underwent an electromyogram for diagnostic confirmation. We realized open surgical treatment at one time, by section of the carpal ligament. The average age of our patients was 4years. The average decline in the surgical study was 19 months. Postoperatively, we noted, in all patients, complete regression of the painful symptoms, a sensory improvement and recovery of the opposition of the thumb. The scarcity of carpal tunnel syndrome in children and the atypical symptoms may cause diagnostic delay, with serious consequences. We keep vigilant and ready to access to additional tests (electromyogram). For our team, the therapeutic approach is a systematic open surgical treatment. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

Tunnel fire dynamics

CERN Document Server

Ingason, Haukur; Lönnermark, Anders

2015-01-01

This book covers a wide range of issues in fire safety engineering in tunnels, describes the phenomena related to tunnel fire dynamics, presents state-of-the-art research, and gives detailed solutions to these major issues. Examples for calculations are provided. The aim is to significantly improve the understanding of fire safety engineering in tunnels. Chapters on fuel and ventilation control, combustion products, gas temperatures, heat fluxes, smoke stratification, visibility, tenability, design fire curves, heat release, fire suppression and detection, CFD modeling, and scaling techniques all equip readers to create their own fire safety plans for tunnels. This book should be purchased by any engineer or public official with responsibility for tunnels. It would also be of interest to many fire protection engineers as an application of evolving technical principles of fire safety.

The Value of Median Nerve Sonography as a Predictor for Short- and Long-Term Clinical Outcomes in Patients with Carpal Tunnel Syndrome: A Prospective Long-Term Follow-Up Study.

Directory of Open Access Journals (Sweden)

Alexander Marschall

Full Text Available To investigate the prognostic value of B-mode and Power Doppler (PD ultrasound of the median nerve for the short- and long-term clinical outcomes of patients with carpal tunnel syndrome (CTS.Prospective study of 135 patients with suspected CTS seen 3 times: at baseline, then at short-term (3 months and long-term (15-36 months follow-up. At baseline, the cross-sectional area (CSA of the median nerve was measured with ultrasound at 4 levels on the forearm and wrist. PD signals were graded semi-quantitatively (0-3. Clinical outcomes were evaluated at each visit with the Boston Questionnaire (BQ and the DASH Questionnaire, as well as visual analogue scales for the patient's assessment of pain (painVAS and physician's global assessment (physVAS. The predictive values of baseline CSA and PD for clinical outcomes were determined with multivariate logistic regression models.Short-term and long-term follow-up data were available for 111 (82.2% and 105 (77.8% patients, respectively. There was a final diagnosis of CTS in 84 patients (125 wrists. Regression analysis revealed that the CSA, measured at the carpal tunnel inlet, predicted short-term clinical improvement according to BQ in CTS patients undergoing carpal tunnel surgery (OR 1.8, p = 0.05, but not in patients treated conservatively. Neither CSA nor PD assessments predicted short-term improvement of painVAS, physVAS or DASH, nor was any of the ultrasound parameters useful for the prediction of long-term clinical outcomes.Ultrasound assessment of the median nerve at the carpal tunnel inlet may predict short-term clinical improvement in CTS patients undergoing carpal tunnel release, but long-term outcomes are unrelated to ultrasound findings.

Small-scale tunnel test for blast performance

International Nuclear Information System (INIS)

Felts, J E; Lee, R J

2014-01-01

The data reported here provide a validation of a small-scale tunnel test as a tool to guide the optimization of new explosives for blast performance in tunnels. The small-scale arrangement consisted of a 2-g booster and 10-g sample mounted at the closed end of a 127 mm diameter by 4.6-m long steel tube with pressure transducers along its length. The three performance characteristics considered were peak pressure, initial energy release, and impulse. The relative performance from five explosives was compared to that from a 1.16-m diameter by 30-m long tunnel that used 2.27-kg samples. The peak pressure values didn't correlate between the tunnels. Partial impulse for the explosives did rank similarly. The initial energy release was determined from a one-dimensional point-source analysis, which nearly tracked with impulse suggesting additional energy released further down the tunnel for some explosives. This test is a viable tool for optimizing compositional variations for blast performance in target scenarios of similar geometry.

Carpal Tunnel Release in Diabetic and Non-Diabetic Patients

Directory of Open Access Journals (Sweden)

Mohammad H Ebrahimzadeh

2013-09-01

Full Text Available Background: Carpal tunnel syndrome (CTS is a compression neuropathy that causes paresthesia, pain or numbness in the territory of median nerve. The aim of this study is to compare the open surgery outcome and patients` satisfaction in carpal tunnel syndrome among diabetic and non-diabetic patients. Methods: In a retrospective cohort study from April 2011 to June 2012, patients suffered from carpal tunnel syndrome at least 6 months, without response to conservative treatment, who had the inclusion and exclusion criteria, were evaluated by the usage of MHQ and WHOQOL-BREEF tests, one month before surgery and three months after that. Carpal tunnel decompression surgery was performed by two surgeons, experienced in hand surgery, which used the same surgical method. Statistical analysis was performed by SPSS 19.0. Results: 24 of patient (34.2% were male and 46 (65.8% were female and there was no significant difference between two groups (P>0.05. MHQ total score before and after surgery was respectively 50.22±7.13 and 63.49±11.28 and this difference was significant (P

Clinical Study on Five Cases of Carpal tunnel syndrome

Directory of Open Access Journals (Sweden)

Kim Il Hwan

2001-12-01

Full Text Available Objections : The purpose of the study was to evaluate the effectiveness of treating the carpal tunnel syndrome by using both the Herbal Acupuncture and herbal medicine therapy on five cases. Methods : For the Herbal Acupuncture, Jungseonguhhyl No. 1 and Hwanglyunhaedoktang were used. For the herbal medicine, Dangguihwalhyul-tang was used. The patients were treated once in every two days; the result was evaluated after ten treatments. Patients' conditions were monitored through their testimony, phalen's test, nerve conduction study and electromyography. Results : In all five cases, the patients showed improvement; in four cases, the patients no longer had most of the clinical symptoms. Based on the result of the nerve conduction study, for the four cases in which the patients no longer displayed most of the clinical symptoms, their nerve conduction rate improved; for the remaining one case, the patient's nerve conduction rate deteriorated. Conclusions : The results of this study demonstrate that combining the Herbal Acupuncture and herbal medicine therapy can have noticeable effects in treating the carpal tunnel syndrome; developing more variety of the herbal acupuncture would lead to even better treatment results.

Simulation of hydrogen releases from fuel-cell vehicles in tunnels

Energy Technology Data Exchange (ETDEWEB)

Houf, William G.; Evans, Greg H.; James, Scott C. [Sandia National Labs., Livermore, CA (United States); Merilo, Erik; Groethe, Mark [SRI International, Menlo Park, CA (United States)

2010-07-01

Simulation results for a hydrogen fuel-cell vehicle in a full-scale tunnel have been performed for the case where hydrogen gas is vented from the vehicle as a result of thermal activation of the pressure relief device (PRD). The same modeling approach used in the full-scale tunnel modeling was validated in a scaled model by comparing simulated results with measured results from a series of scaled-tunnel test experiments performed at the SRI Corral Hollow test facility. Results of the simulations were found to be in good agreement with the experimental data. Finally, a rudimentary risk analysis indicated that the level of potential risk from hydrogen vehicles accidents involving thermally activated PRDs in tunnels does not appear to significantly increase the current level of individual risk to the public from everyday life. (orig.)

Residence time of contaminants released in surface coal mines -- a wind-tunnel study

Energy Technology Data Exchange (ETDEWEB)

Thompson, R.S. [Environmental Protection Agency, Research Triangle Park, NC (United States)

1994-12-31

Surface coal mining operations (blasting, shoveling, loading, trucking, etc.) are sources of airborne particles. The 1990 Clean Air Act Amendments direct the EPA to analyze the accuracy of the Industrial Source Complex model and the AP-42 emission factors, and to make revisions as may be necessary to eliminate any significant over-prediction of air concentration of fugitive particles from surface coal mines. A wind-tunnel study was performed at the US EPA`s Fluid Modeling Facility to investigate dispersion from surface coal mines in support of the dispersion modeling activities. Described here is the portion of the study directed at determining the residence time that material released near the floor of a mine will stay within the mine.

Tunnel fire testing and modeling the Morgex North tunnel experiment

CERN Document Server

Borghetti, Fabio; Gandini, Paolo; Frassoldati, Alessio; Tavelli, Silvia

2017-01-01

This book aims to cast light on all aspects of tunnel fires, based on experimental activities and theoretical and computational fluid dynamics (CFD) analyses. In particular, the authors describe a transient full-scale fire test (~15 MW), explaining how they designed and performed the experimental activity inside the Morgex North tunnel in Italy. The entire organization of the experiment is described, from preliminary evaluations to the solutions found for management of operational difficulties and safety issues. This fire test allowed the collection of different measurements (temperature, air velocity, smoke composition, pollutant species) useful for validating and improving CFD codes and for testing the real behavior of the tunnel and its safety systems during a diesel oil fire with a significant heat release rate. Finally, the fire dynamics are compared with empirical correlations, CFD simulations, and literature measurements obtained in other similar tunnel fire tests. This book will be of interest to all ...

Fire analyses in central and disposal tunnels by APROS

International Nuclear Information System (INIS)

Peltokorpi, L.; Kukkola, T.; Nieminen, J.

2012-12-01

The central tunnels and the disposal tunnels on the north-east disposal area are the target areas of the fire studies. Target is to maintain under pressure in the fire zone in case of a fire. In the central tunnels a fire of a drilling jumbo with moderate fire propagation is used as heat release rate. In the disposal tunnel the heat release rate of a canister transfer and installation vehicle fire received as a result of the pyrolysis analyze as well as an average heat release rate of a van fire are used. Inlet air is to be conducted to the back end of the fire zone and the exhaust is to be lead out from the beginning of the fire zone. The worst location of the fire is in the beginning of the fire zone just below of the exhaust air clap valve. The size of the fire zone does not have big impact on pressure. In all analyzed cases the fire zone remains too long time over pressurized. Inlet air flow of a 30 m 3 /s is too much. The rotation controlled booster blowers will solve the pressure problems of the fire zone in fire cases. The rotation is controlled by the fire zone pressure. The fire of the canister transfer and installation vehicle in the central tunnel will not cause problems. The disposal tunnel fire door should be kept open, if the canister transfer and installation vehicle or the bentonite blocks transfer and installation vehicle is driven into the disposal tunnel. If a fire is caught in the disposal tunnel then the fire zone in the central tunnel is to be closed and the pressure is controlled by the rotation controlled booster blowers. If a personnel car or a van is driven into the disposal tunnel, then fire door of the disposal is to be kept closed against fires in the central tunnel. (orig.)

Measuring fire size in tunnels

International Nuclear Information System (INIS)

Guo, Xiaoping; Zhang, Qihui

2013-01-01

A new measure of fire size Q′ has been introduced in longitudinally ventilated tunnel as the ratio of flame height to the height of tunnel. The analysis in this article has shown that Q′ controls both the critical velocity and the maximum ceiling temperature in the tunnel. Before the fire flame reaches tunnel ceiling (Q′ 1.0), Fr approaches a constant value. This is also a well-known phenomenon in large tunnel fires. Tunnel ceiling temperature shows the opposite trend. Before the fire flame reaches the ceiling, it increases very slowly with the fire size. Once the flame has hit the ceiling of tunnel, temperature rises rapidly with Q′. The good agreement between the current prediction and three different sets of experimental data has demonstrated that the theory has correctly modelled the relation among the heat release rate of fire, ventilation flow and the height of tunnel. From design point of view, the theoretical maximum of critical velocity for a given tunnel can help to prevent oversized ventilation system. -- Highlights: • Fire sizing is an important safety measure in tunnel design. • New measure of fire size a function of HRR of fire, tunnel height and ventilation. • The measure can identify large and small fires. • The characteristics of different fire are consistent with observation in real fires

Tunneling magnetoresistance and electroresistance in Fe/PbTiO3/Fe multiferroic tunnel junctions

International Nuclear Information System (INIS)

Dai, Jian-Qing

2016-01-01

We perform first-principles electronic structure and spin-dependent transport calculations for a Fe/PbTiO 3 /Fe multiferroic tunnel junction with asymmetric TiO 2 - and PbO-terminated interfaces. We demonstrate that the interfacial electronic reconstruction driven by the in situ screening of ferroelectric polarization, in conjunction with the intricate complex band structure of barrier, play a decisive role in controlling the spin-dependent tunneling. Reversal of ferroelectric polarization results in a transition from insulating to half-metal-like conducting state for the interfacial Pb 6p z orbitals, which acts as an atomic-scale spin-valve by releasing the tunneling current in antiparallel magnetization configuration as the ferroelectric polarization pointing to the PbO-terminated interface. This effect produces large change in tunneling conductance. Our results open an attractive avenue in designing multiferroic tunnel junctions with excellent performance by exploiting the interfacial electronic reconstruction originated from the in situ screening of ferroelectric polarization.

Atomistic nature in band-to-band tunneling in two-dimensional silicon pn tunnel diodes

International Nuclear Information System (INIS)

Tabe, Michiharu; Tan, Hoang Nhat; Mizuno, Takeshi; Muruganathan, Manoharan; Anh, Le The; Mizuta, Hiroshi; Nuryadi, Ratno; Moraru, Daniel

2016-01-01

We study low-temperature transport properties of two-dimensional (2D) Si tunnel diodes, or Si Esaki diodes, with a lateral layout. In ordinary Si Esaki diodes, interband tunneling current is severely limited because of the law of momentum conservation, while nanoscale Esaki diodes may behave differently due to the dopants in the narrow depletion region, by atomistic effects which release such current limitation. In thin-Si lateral highly doped pn diodes, we find clear signatures of interband tunneling between 2D-subbands involving phonon assistance. More importantly, the tunneling current is sharply enhanced in a narrow voltage range by resonance via a pair of a donor- and an acceptor-atom in the pn junction region. Such atomistic behavior is recognized as a general feature showing up only in nanoscale tunnel diodes. In particular, a donor-acceptor pair with deeper ground-state energies is likely to be responsible for such a sharply enhanced current peak, tunable by external biases.

The diagnostic efficacy of clinical findings and electrophysiological studies in carpal tunnel syndrome

OpenAIRE

Buyukkoyuncu Pekel, Nilufer; Nar Senol, Pelin; Yildiz, Demet; Kilic, Ahmet Kasim; Kamaci Sener, Deniz; Seferoglu, Meral; Gunes, Aygul

2017-01-01

Objective. The aim of the study was to examine the relation between clinical findings, neurological examination and electrophysiological studies in diagnosing carpal tunnel syndrome (CTS) and share our institutional experience in patients with CTS. Methods. Patients presenting with complaints of pain, paresthesia, and weakness in hands who diagnosed CTS between 2014 and 2015 were examined retrospectively. Demographic characteristics, clinical and neurological examination findings and electrod...

Tunneling magnetoresistance and electroresistance in Fe/PbTiO{sub 3}/Fe multiferroic tunnel junctions

Energy Technology Data Exchange (ETDEWEB)

Dai, Jian-Qing, E-mail: djqkust@sina.com [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming 650093 (China)

2016-08-21

We perform first-principles electronic structure and spin-dependent transport calculations for a Fe/PbTiO{sub 3}/Fe multiferroic tunnel junction with asymmetric TiO{sub 2}- and PbO-terminated interfaces. We demonstrate that the interfacial electronic reconstruction driven by the in situ screening of ferroelectric polarization, in conjunction with the intricate complex band structure of barrier, play a decisive role in controlling the spin-dependent tunneling. Reversal of ferroelectric polarization results in a transition from insulating to half-metal-like conducting state for the interfacial Pb 6p{sub z} orbitals, which acts as an atomic-scale spin-valve by releasing the tunneling current in antiparallel magnetization configuration as the ferroelectric polarization pointing to the PbO-terminated interface. This effect produces large change in tunneling conductance. Our results open an attractive avenue in designing multiferroic tunnel junctions with excellent performance by exploiting the interfacial electronic reconstruction originated from the in situ screening of ferroelectric polarization.

Management of Carpal Tunnel Syndrome.

Science.gov (United States)

Mooar, Pekka A; Doherty, William J; Murray, Jayson N; Pezold, Ryan; Sevarino, Kaitlyn S

2018-03-15

The American Academy of Orthopaedic Surgeons (AAOS) has developed Appropriate Use Criteria (AUC) for Management of Carpal Tunnel Syndrome. Evidence-based information, in conjunction with the clinical expertise of physicians, was used to develop the criteria to improve patient care and obtain best outcomes while considering the subtleties and distinctions necessary in making clinical decisions. To provide the evidence foundation for this AUC, the AAOS Evidence-Based Medicine Unit provided the writing panel and voting panel with the 2016 AAOS Clinical Practice Guideline titled Management of Carpal Tunnel Syndrome Evidence-Based Clinical Practice Guideline. The Management of Carpal Tunnel Syndrome AUC clinical patient scenarios were derived from indications typical of patients with suspected carpal tunnel syndrome in clinical practice, as well as from current evidence-based clinical practice guidelines and supporting literature to identify the appropriateness of treatments. The 135 patient scenarios and 6 treatments were developed by the writing panel, a group of clinicians who are specialists in this AUC topic. Next, a separate, multidisciplinary, voting panel (made up of specialists and nonspecialists) rated the appropriateness of treatment of each patient scenario using a 9-point scale to designate a treatment as Appropriate (median rating, 7 to 9), May Be Appropriate (median rating, 4 to 6), or Rarely Appropriate (median rating, 1 to 3).

"Hand surgeons probably don't starve": Patient's perceptions of physician reimbursements for performing an open carpal tunnel release.

Science.gov (United States)

Kokko, Kyle P; Lipman, Adam J; Sapienza, Anthony; Capo, John T; Barfield, William R; Paksima, Nader

2015-12-01

The purpose of this study is to evaluate patient's perceptions of physician reimbursement for the most commonly performed surgery on the hand, a carpal tunnel release (CTR). Anonymous physician reimbursement surveys were given to patients and non-patients in the waiting rooms of orthopaedic hand physicians' offices and certified hand therapist's offices. The survey consisted of 13 questions. Respondents were asked (1) what they thought a surgeon should be paid to perform a carpal tunnel release, (2) to estimate how much Medicare reimburses the surgeon, and (3) about how health care dollars should be divided among the surgeon, the anesthesiologist, and the hospital or surgery center. Descriptive subject data included age, gender, income, educational background, and insurance type. Patients thought that hand surgeons should receive $5030 for performing a CTR and the percentage of health care funds should be distributed primarily to the hand surgeon (56 %), followed by the anesthesiologist (23 %) and then the hospital/surgery center (21 %). They estimated that Medicare reimburses the hand surgeon $2685 for a CTR. Most patients (86 %) stated that Medicare reimbursement was "lower" or "much lower" than what it should be. Respondents believed that hand surgeons should be reimbursed greater than 12 times the Medicare reimbursement rate of approximately $412 and that the physicians (surgeons and anesthesiologist) should command most of the health care funds allocated to this treatment. This study highlights the discrepancy between patient's perceptions and actual physician reimbursement as it relates to federal health care. Efforts should be made to educate patients on this discrepancy.

Temporal trend of carpal tunnel release surgery: a population-based time series analysis.

Directory of Open Access Journals (Sweden)

Naif Fnais

Full Text Available BACKGROUND: Carpal tunnel release (CTR is among the most common hand surgeries, although little is known about its pattern. In this study, we aimed to investigate temporal trends, age and gender variation and current practice patterns in CTR surgeries. METHODS: We conducted a population-based time series analysis among over 13 million residents of Ontario, who underwent operative management for carpal tunnel syndrome (CTS from April 1, 1992 to March 31, 2010 using administrative claims data. RESULTS: The primary analysis revealed a fairly stable procedure rate of approximately 10 patients per 10,000 population per year receiving CTRs without any significant, consistent temporal trend (p = 0.94. Secondary analyses revealed different trends in procedure rates according to age. The annual procedure rate among those age >75 years increased from 22 per 10,000 population at the beginning of the study period to over 26 patients per 10,000 population (p<0.01 by the end of the study period. CTR surgical procedures were approximately two-fold more common among females relative to males (64.9% vs. 35.1 respectively; p<0.01. Lastly, CTR procedures are increasingly being conducted in the outpatient setting while procedures in the inpatient setting have been declining steadily - the proportion of procedures performed in the outpatient setting increased from 13% to over 30% by 2010 (p<0.01. CONCLUSION: Overall, CTR surgical-procedures are conducted at a rate of approximately 10 patients per 10,000 population annually with significant variation with respect to age and gender. CTR surgical procedures in ambulatory-care facilities may soon outpace procedure rates in the in-hospital setting.

Final report on the Controlled Cold Helium Spill Test in the LHC tunnel at CERN

International Nuclear Information System (INIS)

Dufay-Chanat, L; Bremer, J; Casas-Cubillos, J; Koettig, T; Vauthier, N; Van Weelderen, R; Winkler, T; Chorowski, M; Grabowski, M; Jedrusyna, A; Lindell, G; Nonis, M

2015-01-01

The 27 km circumference LHC underground tunnel is a space in which the helium cooled LHC magnets are installed. The vacuum enclosures of the superconducting magnets are protected by over-pressure safety relief devices that open whenever cold helium escapes either from the magnet cold enclosure or from the helium supply headers, into this vacuum enclosure. A 3-m long no stay zone around these devices is defined based on scale model studies, protecting the personnel against cold burns or asphyxia caused by such a helium release event. Recently, several simulation studies have been carried out modelling the propagation of the helium/air mixture, resulting from the opening of such a safety device, along the tunnel. The released helium flows vary in the range between 1 kg/s and 0.1 kg/s. To validate these different simulation studies, real life mock-up tests have been performed inside the LHC tunnel, releasing helium flow rates of 1 kg/s, 0.3 kg/s and 0.1 kg/s. For each test, up to 1000 liters of liquid helium were released under standard operational tunnel conditions. The data recorded include oxygen concentration, temperature and flow speed measurements, and video footage used to assess qualitatively the visibility. These measurements have been made in the up- and downstream directions, with respect to the air ventilation flow, of the spill point.This paper presents the experimental set-up under which these release tests were made, the effects of these releases on the atmospheric tunnel condition as a function of the release flow rate. We discuss the modification to the personnel access conditions to the LHC tunnel that are presently implemented as a result of these tests. (paper)

Final report on the Controlled Cold Helium Spill Test in the LHC tunnel at CERN

Science.gov (United States)

Dufay-Chanat, L.; Bremer, J.; Casas-Cubillos, J.; Chorowski, M.; Grabowski, M.; Jedrusyna, A.; Lindell, G.; Nonis, M.; Koettig, T.; Vauthier, N.; van Weelderen, R.; Winkler, T.

2015-12-01

The 27 km circumference LHC underground tunnel is a space in which the helium cooled LHC magnets are installed. The vacuum enclosures of the superconducting magnets are protected by over-pressure safety relief devices that open whenever cold helium escapes either from the magnet cold enclosure or from the helium supply headers, into this vacuum enclosure. A 3-m long no stay zone around these devices is defined based on scale model studies, protecting the personnel against cold burns or asphyxia caused by such a helium release event. Recently, several simulation studies have been carried out modelling the propagation of the helium/air mixture, resulting from the opening of such a safety device, along the tunnel. The released helium flows vary in the range between 1 kg/s and 0.1 kg/s. To validate these different simulation studies, real life mock-up tests have been performed inside the LHC tunnel, releasing helium flow rates of 1 kg/s, 0.3 kg/s and 0.1 kg/s. For each test, up to 1000 liters of liquid helium were released under standard operational tunnel conditions. The data recorded include oxygen concentration, temperature and flow speed measurements, and video footage used to assess qualitatively the visibility. These measurements have been made in the up- and downstream directions, with respect to the air ventilation flow, of the spill point. This paper presents the experimental set-up under which these release tests were made, the effects of these releases on the atmospheric tunnel condition as a function of the release flow rate. We discuss the modification to the personnel access conditions to the LHC tunnel that are presently implemented as a result of these tests.

Intraneural blood flow analysis during an intraoperative Phalen's test in carpal tunnel syndrome.

Science.gov (United States)

Yayama, Takafumi; Kobayashi, Shigeru; Awara, Kousuke; Takeno, Kenichi; Miyazaki, Tsuyoshi; Kubota, Masafumi; Negoro, Kohei; Baba, Hisatoshi

2010-08-01

Phalen's test has been one of the most significant of clinical signs when making a clinical diagnosis of idiopathic carpal tunnel syndrome (CTS). However, it is unknown whether intraneural blood flow changes during Phalen's test in patients with CTS. In this study, an intraoperative Phalen's test was conducted in patients with CTS to observe the changes in intraneural blood flow using a laser Doppler flow meter. During Phalen's test, intraneural blood flow showed a sharp decrease, which lasted for 1 min. Intraneural blood flow decreased by 56.7%-100% (average, 78.0%) in the median nerve relative to the blood flow before the test. At 1 min after completing the test, intraneural blood flow returned to the baseline value. After carpal tunnel release, there was no marked decrease in intraneural blood flow. This study demonstrated that the blood flow in the median nerve is reduced when Phalen's test is performed in vivo. Copyright 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Flexible MgO Barrier Magnetic Tunnel Junctions.

Science.gov (United States)

Loong, Li Ming; Lee, Wonho; Qiu, Xuepeng; Yang, Ping; Kawai, Hiroyo; Saeys, Mark; Ahn, Jong-Hyun; Yang, Hyunsoo

2016-07-01

Flexible MgO barrier magnetic tunnel junction (MTJ) devices are fabricated using a transfer printing process. The flexible MTJ devices yield significantly enhanced tunneling magnetoresistance of ≈300% and improved abruptness of switching, as residual strain in the MTJ structure is released during the transfer process. This approach could be useful for flexible electronic systems that require high-performance memory components. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Top Pilot Tunnel Preconditioning Method for the Prevention of Extremely Intense Rockbursts in Deep Tunnels Excavated by TBMs

Science.gov (United States)

Zhang, Chuanqing; Feng, Xiating; Zhou, Hui; Qiu, Shili; Wu, Wenping

2012-05-01

The headrace tunnels at the Jinping II Hydropower Station cross the Jinping Mountain with a maximum overburden depth of 2,525 m, where 80% of the strata along the tunnels consist of marble. A number of extremely intense rockbursts occurred during the excavation of the auxiliary tunnels and the drainage tunnel. In particular, a tunnel boring machine (TBM) was destroyed by an extremely intense rockburst in a 7.2-m-diameter drainage tunnel. Two of the four subsequent 12.4-m-diameter headrace tunnels will be excavated with larger size TBMs, where a high risk of extremely intense rockbursts exists. Herein, a top pilot tunnel preconditioning method is proposed to minimize this risk, in which a drilling and blasting method is first recommended for the top pilot tunnel excavation and support, and then the TBM excavation of the main tunnel is conducted. In order to evaluate the mechanical effectiveness of this method, numerical simulation analyses using the failure approaching index, energy release rate, and excess shear stress indices are carried out. Its construction feasibility is discussed as well. Moreover, a microseismic monitoring technique is used in the experimental tunnel section for the real-time monitoring of the microseismic activities of the rock mass in TBM excavation and for assessing the effect of the top pilot tunnel excavation in reducing the risk of rockbursts. This method is applied to two tunnel sections prone to extremely intense rockbursts and leads to a reduction in the risk of rockbursts in TBM excavation.

DNS Tunneling Detection Method Based on Multilabel Support Vector Machine

Directory of Open Access Journals (Sweden)

Ahmed Almusawi

2018-01-01

Full Text Available DNS tunneling is a method used by malicious users who intend to bypass the firewall to send or receive commands and data. This has a significant impact on revealing or releasing classified information. Several researchers have examined the use of machine learning in terms of detecting DNS tunneling. However, these studies have treated the problem of DNS tunneling as a binary classification where the class label is either legitimate or tunnel. In fact, there are different types of DNS tunneling such as FTP-DNS tunneling, HTTP-DNS tunneling, HTTPS-DNS tunneling, and POP3-DNS tunneling. Therefore, there is a vital demand to not only detect the DNS tunneling but rather classify such tunnel. This study aims to propose a multilabel support vector machine in order to detect and classify the DNS tunneling. The proposed method has been evaluated using a benchmark dataset that contains numerous DNS queries and is compared with a multilabel Bayesian classifier based on the number of corrected classified DNS tunneling instances. Experimental results demonstrate the efficacy of the proposed SVM classification method by obtaining an f-measure of 0.80.

Water Tunnel Studies of Dynamic Wing Flap Effects

Science.gov (United States)

2016-06-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited WATER TUNNEL...Master’s Thesis 4. TITLE AND SUBTITLE WATER TUNNEL STUDIES OF DYNAMIC WING FLAP EFFECTS 5. FUNDING NUMBERS 6. AUTHOR(S) Edgar E. González 7. PERFORMING...ABSTRACT (maximum 200 words ) The flow features developing over a two-element NACA 0012 airfoil, with the rear portion serving as a trailing edge flap

The effect of buffer-layer on the steady-state energy release rate of a tunneling crack in a wind turbine blade joint

DEFF Research Database (Denmark)

Jørgensen, Jeppe Bjørn; Sørensen, Bent F.; Kildegaard, Casper

2018-01-01

propagation of tunneling cracks. However, for wind turbine blade relevant material combinations it is found more effective to reduce the thickness of the adhesive layer since the stiffness mismatch between the existing laminate and the adhesive is already high. The effect of material orthotropy was found......The effect of a buffer-layer on the steady-state energy release rate of a tunneling crack in the adhesive layer of a wind turbine blade joint, loaded in tension, is investigated using a parametric 2D tri-material finite element model. The idea of embedding a buffer-layer in-between the adhesive...... and the basis glass fiber laminate to improve the existing joint design is novel, but the implications hereof need to be addressed.The results show that it is advantageous to embed a buffer-layer near the adhesive with controllable thickness-and stiffness properties in order to improve the joint design against...

Bone tunnel diameter measured with CT after anterior cruciate ligament reconstruction using double-bundle auto-hamstring tendors: Clinical implications

Energy Technology Data Exchange (ETDEWEB)

Yoon, Soo Jeong; Yoon, Young Cheol; Bae, So Young; Wang, Joon Ho [Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul (Korea, Republic of)

2015-12-15

To evaluate the correlation between bone tunnel diameter after anterior cruciate ligament (ACL) reconstruction measured by computed tomography (CT) using multiplanar reconstruction (MPR) and stability or clinical scores. Forty-seven patients (41 men and 6 women, mean age: 34 years) who had undergone ACL reconstruction with the double bundle technique using auto-hamstring graft and had subsequently received CT scans immediately after the surgery (T1: range, 1-4 days, mean, 2.5 days) and at a later time (T2: range, 297-644 days, mean, 410.4 days) were enrolled in this study. The diameter of each tunnel (two femoral and two tibial) at both T1 and T2 were independently measured using MPR technique by two radiologists. Stability and clinical scores were evaluated with a KT-2000 arthrometer, International Knee Documentation Committee objective scores, and the Lysholm score. Statistical analysis of the correlation between the diameter at T2 or the interval diameter change ratio ([T2 - T1] / T1) and clinical scores or stability was investigated. The tibial bone tunnels for the anteromedial bundles were significantly widened at T2 compared with T1 (observer 1, 0.578 mm to 0.698 mm, p value of < 0.001; observer 2, 0.581 mm to 0.707 mm, p value of < 0.001). There was no significant correlation between the diameter at T2 and stability or clinical scores and between the interval change ratio ([T2 - T1] / T1) and stability or clinical scores (corrected p values for all were 1.0). Intraobserver agreement for measurements was excellent (> 0.8) for both observers. Interobserver agreement for measurement was excellent (> 0.8) except for the most distal portion of the femoral bone tunnel for anterior medial bundle in immediate postoperative CT, which showed moderate agreement (concordance correlation coefficient = 0.6311).Neither the diameter nor its change ratio during interval follow-up is correlated with stability or clinical scores.

Bone tunnel diameter measured with CT after anterior cruciate ligament reconstruction using double-bundle auto-hamstring tendors: Clinical implications

International Nuclear Information System (INIS)

Yoon, Soo Jeong; Yoon, Young Cheol; Bae, So Young; Wang, Joon Ho

2015-01-01

To evaluate the correlation between bone tunnel diameter after anterior cruciate ligament (ACL) reconstruction measured by computed tomography (CT) using multiplanar reconstruction (MPR) and stability or clinical scores. Forty-seven patients (41 men and 6 women, mean age: 34 years) who had undergone ACL reconstruction with the double bundle technique using auto-hamstring graft and had subsequently received CT scans immediately after the surgery (T1: range, 1-4 days, mean, 2.5 days) and at a later time (T2: range, 297-644 days, mean, 410.4 days) were enrolled in this study. The diameter of each tunnel (two femoral and two tibial) at both T1 and T2 were independently measured using MPR technique by two radiologists. Stability and clinical scores were evaluated with a KT-2000 arthrometer, International Knee Documentation Committee objective scores, and the Lysholm score. Statistical analysis of the correlation between the diameter at T2 or the interval diameter change ratio ([T2 - T1] / T1) and clinical scores or stability was investigated. The tibial bone tunnels for the anteromedial bundles were significantly widened at T2 compared with T1 (observer 1, 0.578 mm to 0.698 mm, p value of < 0.001; observer 2, 0.581 mm to 0.707 mm, p value of < 0.001). There was no significant correlation between the diameter at T2 and stability or clinical scores and between the interval change ratio ([T2 - T1] / T1) and stability or clinical scores (corrected p values for all were 1.0). Intraobserver agreement for measurements was excellent (> 0.8) for both observers. Interobserver agreement for measurement was excellent (> 0.8) except for the most distal portion of the femoral bone tunnel for anterior medial bundle in immediate postoperative CT, which showed moderate agreement (concordance correlation coefficient = 0.6311).Neither the diameter nor its change ratio during interval follow-up is correlated with stability or clinical scores

Using Time-Driven Activity-Based Costing as a Key Component of the Value Platform: A Pilot Analysis of Colonoscopy, Aortic Valve Replacement and Carpal Tunnel Release Procedures.

Science.gov (United States)

Martin, Jacob A; Mayhew, Christopher R; Morris, Amanda J; Bader, Angela M; Tsai, Mitchell H; Urman, Richard D

2018-04-01

Time-driven activity-based costing (TDABC) is a methodology that calculates the costs of healthcare resources consumed as a patient moves along a care process. Limited data exist on the application of TDABC from the perspective of an anesthesia provider. We describe the use of TDABC, a bottom-up costing strategy and financial outcomes for three different medical-surgical procedures. In each case, a multi-disciplinary team created process maps describing the care delivery cycle for a patient encounter using the TDABC methodology. Each step in a process map delineated an activity required for delivery of patient care. The resources (personnel, equipment and supplies) associated with each step were identified. A per minute cost for each resource expended was generated, known as the capacity cost rate, and multiplied by its time requirement. The total cost for an episode of care was obtained by adding the cost of each individual resource consumed as the patient moved along a clinical pathway. We built process maps for colonoscopy in the gastroenterology suite, calculated costs of an aortic valve replacement by comparing surgical aortic valve replacement (SAVR) versus transcatheter aortic valve replacement (TAVR) techniques, and determined the cost of carpal tunnel release in an operating room versus an ambulatory procedure room. TDABC is central to the value-based healthcare platform. Application of TDABC provides a framework to identify process improvements for health care delivery. The first case demonstrates cost-savings and improved wait times by shifting some of the colonoscopies scheduled with an anesthesiologist from the main hospital to the ambulatory facility. In the second case, we show that the deployment of an aortic valve via the transcatheter route front loads the costs compared to traditional, surgical replacement. The last case demonstrates significant cost savings to the healthcare system associated with re-organization of staff required to execute a

Clinical and radiographic evaluation of cermet tunnel restorations on primary molars.

Science.gov (United States)

Zenkner, J E; Baratieri, L N; Monteiro, S J; de Andrada, M A; Vieira, L C

1993-11-01

Fifty-one restorations of the tunnel type were performed with "cermet" cement on primary molars. The restorations were assessed clinically, radiographically, and by direct examination of the proximal surface 6 months (group I) and 12 months (group II) after placement. The incidence of fractured marginal ridges was found to be 3.8% in group I and 4.2% in group II. All restorations had their occlusal portion intact and were caries-free. Clinically detectable occlusal wear was found in 7.7% of teeth in group I and in 4.2% of teeth in group II. No correlation was found between direct and radiographic assessment of proximal caries. White spots, without carious penetration, were detected on 53.8% of proximal surfaces at 6 months and on 60.0% of proximal surfaces at 12 months.

Fire analyses in central and disposal tunnels by APROS; Keskus- ja loppusijoitustunneleiden palotarkasteluja APROSilla

Energy Technology Data Exchange (ETDEWEB)

Peltokorpi, L.; Kukkola, T.; Nieminen, J. [Fortum Power and Heat Oy, Espoo (Finland)

2012-12-15

The central tunnels and the disposal tunnels on the north-east disposal area are the target areas of the fire studies. Target is to maintain under pressure in the fire zone in case of a fire. In the central tunnels a fire of a drilling jumbo with moderate fire propagation is used as heat release rate. In the disposal tunnel the heat release rate of a canister transfer and installation vehicle fire received as a result of the pyrolysis analyze as well as an average heat release rate of a van fire are used. Inlet air is to be conducted to the back end of the fire zone and the exhaust is to be lead out from the beginning of the fire zone. The worst location of the fire is in the beginning of the fire zone just below of the exhaust air clap valve. The size of the fire zone does not have big impact on pressure. In all analyzed cases the fire zone remains too long time over pressurized. Inlet air flow of a 30 m{sup 3}/s is too much. The rotation controlled booster blowers will solve the pressure problems of the fire zone in fire cases. The rotation is controlled by the fire zone pressure. The fire of the canister transfer and installation vehicle in the central tunnel will not cause problems. The disposal tunnel fire door should be kept open, if the canister transfer and installation vehicle or the bentonite blocks transfer and installation vehicle is driven into the disposal tunnel. If a fire is caught in the disposal tunnel then the fire zone in the central tunnel is to be closed and the pressure is controlled by the rotation controlled booster blowers. If a personnel car or a van is driven into the disposal tunnel, then fire door of the disposal is to be kept closed against fires in the central tunnel. (orig.)

Tunnel magnetoresistance in alumina, magnesia and composite tunnel barrier magnetic tunnel junctions

International Nuclear Information System (INIS)

Schebaum, Oliver; Drewello, Volker; Auge, Alexander; Reiss, Guenter; Muenzenberg, Markus; Schuhmann, Henning; Seibt, Michael; Thomas, Andy

2011-01-01

Using magnetron sputtering, we have prepared Co-Fe-B/tunnel barrier/Co-Fe-B magnetic tunnel junctions with tunnel barriers consisting of alumina, magnesia, and magnesia-alumina bilayer systems. The highest tunnel magnetoresistance ratios we found were 73% for alumina and 323% for magnesia-based tunnel junctions. Additionally, tunnel junctions with a unified layer stack were prepared for the three different barriers. In these systems, the tunnel magnetoresistance ratios at optimum annealing temperatures were found to be 65% for alumina, 173% for magnesia, and 78% for the composite tunnel barriers. The similar tunnel magnetoresistance ratios of the tunnel junctions containing alumina provide evidence that coherent tunneling is suppressed by the alumina layer in the composite tunnel barrier. - Research highlights: → Transport properties of Co-Fe-B/tunnel barrier/Co-Fe-B magnetic tunnel junctions. → Tunnel barrier consists of MgO, Al-Ox, or MgO/Al-Ox bilayer systems. → Limitation of TMR-ratio in composite barrier tunnel junctions to Al-Ox values. → Limitation indicates that Al-Ox layer is causing incoherent tunneling.

Treatment of carpal tunnel syndrome with polarized polychromatic noncoherent light (Bioptron light): a preliminary, prospective, open clinical trial.

Science.gov (United States)

Stasinopoulos, D; Stasinopoulos, I; Johnson, M I

2005-04-01

Our aim was to assess the efficacy of polarized polychromatic noncoherent light (Bioptron light) in the treatment of idiopathic carpal tunnel syndrome. Carpal tunnel syndrome is the most common compression neuropathy, but no satisfactory conservative treatment is available at present. An uncontrolled experimental study was conducted in patients who visited our clinic from mid-2001 to mid-2002. A total of 25 patients (22 women and three men) with unilateral idiopathic carpal tunnel syndrome, mild to moderate nocturnal pain, and paraesthesia lasting >3 months participated in the study. The average age of the patients was 47.4 years and the average duration of patients' symptoms was 5.2 months. Polarized polychromatic noncoherent light (Bioptron light) was administered perpendicular to the carpal tunnel area. The irradiation time for each session was 6 min at an operating distance of 5-10 cm from the carpal tunnel area, three times weekly for 4 weeks. Outcome measures used were the participants' global assessments of nocturnal pain and paraesthesia, respectively, at 4 weeks and 6 months. At 4 weeks, two patients (8%) had no change in nocturnal pain, six (24%) were in slightly less nocturnal pain, 12 (48%) were much better in regard to nocturnal pain and five (20%) were pain-free. At 6 months, three patients (12%) were slightly better in regard to nocturnal pain, 13 (52%) were much better regarding nocturnal pain, and nine patients (36%) were pain-free. At 4 weeks, four patients (16%) had no change in paraesthesia, five (20%) were slightly better, 13 patients (52%) were much better, and three patients (12%) were without paraesthesia. At 6 months, two patients (8%) had no change in paraesthesia, two (8%) were slightly better, 14 (56%) were much better, and seven (28%) were without paraesthesia. Nocturnal pain and paraesthesia associated with idiopathic carpal tunnel syndrome improved during polarized polychromatic noncoherent light (Bioptron light) treatment. Controlled

Submucosal tunneling techniques: current perspectives.

Science.gov (United States)

Kobara, Hideki; Mori, Hirohito; Rafiq, Kazi; Fujihara, Shintaro; Nishiyama, Noriko; Ayaki, Maki; Yachida, Tatsuo; Matsunaga, Tae; Tani, Johji; Miyoshi, Hisaaki; Yoneyama, Hirohito; Morishita, Asahiro; Oryu, Makoto; Iwama, Hisakazu; Masaki, Tsutomu

2014-01-01

Advances in endoscopic submucosal dissection include a submucosal tunneling technique, involving the introduction of tunnels into the submucosa. These tunnels permit safer offset entry into the peritoneal cavity for natural orifice transluminal endoscopic surgery. Technical advantages include the visual identification of the layers of the gut, blood vessels, and subepithelial tumors. The creation of a mucosal flap that minimizes air and fluid leakage into the extraluminal cavity can enhance the safety and efficacy of surgery. This submucosal tunneling technique was adapted for esophageal myotomy, culminating in its application to patients with achalasia. This method, known as per oral endoscopic myotomy, has opened up the new discipline of submucosal endoscopic surgery. Other clinical applications of the submucosal tunneling technique include its use in the removal of gastrointestinal subepithelial tumors and endomicroscopy for the diagnosis of functional and motility disorders. This review suggests that the submucosal tunneling technique, involving a mucosal safety flap, can have potential values for future endoscopic developments.

The value of high-resolution sonography and MR imaging in the diagnosis and follow-up of carpal tunnel syndrome

International Nuclear Information System (INIS)

Buchberger, W.; Judmaier, W.; Birbamer, G.; Hasenoehrl, K.; Schmidauer, C.

1993-01-01

120 wrists of 105 patients with carpal tunnel syndrome were studied preoperatively by high-resolution sonography. Follow-up examinations after carpal tunnel release were performed in 72 wrists. In addition, 40 wrists were examined preoperatively, and 20 wrists were examined postoperatively by MR imaging. Based on quantitative analysis of the cross-sectional area and shape of the median nerve and of the palmar bowing of the flexor retinaculum, sonography established the diagnosis in 95% of cases. MR was superior in the evaluation of mild degrees of median nerve compression, and in the detection of possible causes of the carpal tunnel syndrome, such as synovitis of the flexor tendon sheaths or ganglionic cysts. In postoperative follow-up, sonographic demonstration of a normally flattened median nerve was an excellent indicator of the successful carpal tunnel release. In 10 patients with persistent or recurrent symptoms after carpal tunnel release, the underlying pathology could be exactly demonstrated by MR. (orig.) [de

Modeling of Turbidity Variation in Two Reservoirs Connected by a Water Transfer Tunnel in South Korea

Directory of Open Access Journals (Sweden)

Jae Chung Park

2017-06-01

Full Text Available The Andong and Imha reservoirs in South Korea are connected by a water transfer tunnel. The turbidity of the Imha reservoir is much higher than that of the Andong reservoir. Thus, it is necessary to examine the movement of turbidity between the two reservoirs via the water transfer tunnel. The aim of this study was to investigate the effect of the water transfer tunnel on the turbidity behavior of the two connecting reservoirs and to further understand the effect of reservoir turbidity distribution as a function of the selective withdrawal depth. This study applied the CE-QUAL-W2, a water quality and 2-dimensional hydrodynamic model, for simulating the hydrodynamic processes of the two reservoirs. Results indicate that, in the Andong reservoir, the turbidity of the released water with the water transfer tunnel was similar to that without the tunnel. However, in the Imha reservoir, the turbidity of the released water with the water transfer tunnel was lower than that without the tunnel. This can be attributed to the higher capacity of the Andong reservoir, which has double the storage of the Imha reservoir. Withdrawal turbidity in the Imha reservoir was investigated using the water transfer tunnel. This study applied three withdrawal selections as elevation (EL. 141.0 m, 146.5 m, and 152.0 m. The highest withdrawal turbidity resulted in EL. 141.0 m, which indicates that the high turbidity current is located at a vertical depth of about 20–30 m because of the density difference. These results will be helpful for understanding the release and selective withdrawal turbidity behaviors for a water transfer tunnel between two reservoirs.

The Beginner's Guide to Wind Tunnels with TunnelSim and TunnelSys

Science.gov (United States)

Benson, Thomas J.; Galica, Carol A.; Vila, Anthony J.

2010-01-01

The Beginner's Guide to Wind Tunnels is a Web-based, on-line textbook that explains and demonstrates the history, physics, and mathematics involved with wind tunnels and wind tunnel testing. The Web site contains several interactive computer programs to demonstrate scientific principles. TunnelSim is an interactive, educational computer program that demonstrates basic wind tunnel design and operation. TunnelSim is a Java (Sun Microsystems Inc.) applet that solves the continuity and Bernoulli equations to determine the velocity and pressure throughout a tunnel design. TunnelSys is a group of Java applications that mimic wind tunnel testing techniques. Using TunnelSys, a team of students designs, tests, and post-processes the data for a virtual, low speed, and aircraft wing.

Joint release rate estimation and measurement-by-measurement model correction for atmospheric radionuclide emission in nuclear accidents: An application to wind tunnel experiments.

Science.gov (United States)

Li, Xinpeng; Li, Hong; Liu, Yun; Xiong, Wei; Fang, Sheng

2018-03-05

The release rate of atmospheric radionuclide emissions is a critical factor in the emergency response to nuclear accidents. However, there are unavoidable biases in radionuclide transport models, leading to inaccurate estimates. In this study, a method that simultaneously corrects these biases and estimates the release rate is developed. Our approach provides a more complete measurement-by-measurement correction of the biases with a coefficient matrix that considers both deterministic and stochastic deviations. This matrix and the release rate are jointly solved by the alternating minimization algorithm. The proposed method is generic because it does not rely on specific features of transport models or scenarios. It is validated against wind tunnel experiments that simulate accidental releases in a heterogonous and densely built nuclear power plant site. The sensitivities to the position, number, and quality of measurements and extendibility of the method are also investigated. The results demonstrate that this method effectively corrects the model biases, and therefore outperforms Tikhonov's method in both release rate estimation and model prediction. The proposed approach is robust to uncertainties and extendible with various center estimators, thus providing a flexible framework for robust source inversion in real accidents, even if large uncertainties exist in multiple factors. Copyright © 2017 Elsevier B.V. All rights reserved.

Application for approval of derived authorized limits for the release of the 190-C trenches and 105-C process water tunnels at the Hanford Site: Volume 2 - source term development

International Nuclear Information System (INIS)

Denham, D.H.; Winslow, S.L.; Moeller, M.P.; Kennedy, W.E. Jr.

1997-03-01

As part of environmental restoration activities at the Hanford Site, Bechtel Hanford, Inc. is conducting a series of evaluations to determine appropriate release conditions for specific facilities following the completion of decontamination and decommissioning projects. The release conditions, with respect to the residual volumetric radioactive contamination, are termed authorized limits. This report presents the summary of the supporting information and the final application for approval of derived authorized limits for the release of the 190-C trenches and the 105-C process water tunnels. This document contains two volumes; this volume (Vol. 2) contains the radiological characterization data, spreadsheet analyses, and radiological source terms

Controlled Cold Helium Spill Test in the LHC Tunnel at CERN

Science.gov (United States)

Koettig, T.; Casas-Cubillos, J.; Chorowski, M.; Dufay-Chanat, L.; Grabowski, M.; Jedrusyna, A.; Lindell, G.; Nonis, M.; Vauthier, N.; van Weelderen, R.; Winkler, T.; Bremer, J.

The helium cooled magnets of the LHC particle accelerator are installed in a confined space, formed by a 27 km circumference 3.8 m diameter underground tunnel. The vacuum enclosures of the superconducting LHC magnets are protected by a lift plate against excessive overpressure created by eventual leaks from the magnet helium bath, or from the helium supply headers. A three-meter long no stay zone has been defined centered to these plates, based on earlier scale model studies, to protect the personnel against the consequences of an eventual opening of such a lift plate. More recently several simulation studies have been carried out modelling the propagation of the resulting helium/air mixture along the tunnel in case of such a cold helium release at a rate in the range of 1 kg/s. To validate the different scale models and simulation studies, real life mock-up tests have been performed in the LHC, releasing about 1000 liter of liquid helium under standard operational tunnel conditions. Data recorded during these tests include oxygen level, temperature and flow speed as well as video recordings, taken up- and downstream of the spill point (-100 m to +200 m) with respect to the ventilation direction in the LHC tunnel. The experimental set-up and measurement results are presented. Generic effects found during the tests will be discussed to allow the transposal to possible cold helium release cases in similar facilities.

Clinical observation of the glaucoma trabeculectomy with tunnel knife making the double-deck scleral flap

Directory of Open Access Journals (Sweden)

Min Fu

2015-07-01

Full Text Available AIM: To study the trabeculectomy clinical effect of use tunnel knife to make double-deck scleral flap and to cut off the layer scleral flap of glaucoma.METHODS:Using the random grouping method to divide 46 cases(60 eyesof glaucoma into the treatment group of 24 cases(32 eyesand control group of 22 cases(28 eyes. The treatment group, tunnel knife was used to make double-deck sclera flap and superficial scleral flap about the size of 5mm×5.5mm,1/3 scleral thickness, under the sclera flap made another one about the size of 3.5mm×4mm, 1/3 scleral thickness, resected the middle layer of the sclera flap, removed 2mm×2mm trabecular tissue, underwent routine peripheral iridectomy, could adjust suture the superficial scleral flap, sutured Ball fascia and bulbar conjunctiva. In control group, routine glaucoma trabeculectomy was undergone.RESULTS:Patients were followed up for 1a, the vision in treatment group was obviously better than that in the control group, with a statistically significant difference(PP>0.05. But after 6 and 12mo, the intraocular pressure of the treatment group were significantly lower than that of the control group, with statistically significant difference(PPCONCLUSION:The trabeculectomy have a good effect to lower the intraocular pressure by use tunnel knife to make double-deck scleral flap and to cut off the layer scleral flap. The scleral flap have uniform thickness, smooth surface, and the function of the filtering bleb maintained for a long time, less postoperative complications, suitable for various types of glaucoma, so it is worthy of clinical promotion.

Macrophage conditioned medium induced cellular network formation in MCF-7 cells through enhanced tunneling nanotube formation and tunneling nanotube mediated release of viable cytoplasmic fragments

International Nuclear Information System (INIS)

Patheja, Pooja; Sahu, Khageswar

2017-01-01

Infiltrating macrophages in tumor microenvironment, through their secreted cytokines and growth factors, regulate several processes of cancer progression such as cancer cell survival, proliferation, invasion, metastasis and angiogenesis. Recently, intercellular cytoplasmic bridges between cancer cells referred as tunneling nanotubes (TNTs) have been recognized as novel mode of intercellular communication between cancer cells. In this study, we investigated the effect of inflammatory mediators present in conditioned medium derived from macrophages on the formation of TNTs in breast adenocarcinoma cells MCF-7. Results show that treatment with macrophage conditioned medium (MφCM) not only enhanced TNT formation between cells but also stimulated the release of independently migrating viable cytoplasmic fragments, referred to as microplasts, from MCF-7 cells. Time lapse microscopy revealed that microplasts were released from parent cancer cells in extracellular space through formation of TNT-like structures. Mitochondria, vesicles and cytoplasm could be transferred from parent cell body to microplasts through connecting TNTs. The microplasts could also be resorbed into the parent cell body by retraction of the connecting TNTs. Microplast formation inhibited in presence cell migration inhibitor, cytochalasin-B. Notably by utilizing migratory machinery within microplasts, distantly located MCF-7 cells formed several TNT based intercellular connections, leading to formation of physically connected network of cells. Together, these results demonstrate novel role of TNTs in microplast formation, novel modes of TNT formation mediated by microplasts and stimulatory effect of MφCM on cellular network formation in MCF-7 cells mediated through enhanced TNT and microplast formation.

Macrophage conditioned medium induced cellular network formation in MCF-7 cells through enhanced tunneling nanotube formation and tunneling nanotube mediated release of viable cytoplasmic fragments

Energy Technology Data Exchange (ETDEWEB)

Patheja, Pooja, E-mail: pooja.patheja8@gmail.com [Laser Biomedical Applications Section, Raja Ramanna Centre for Advanced Technology, Indore 452013, Madhya Pradesh (India); Homi Bhabha National Institute, Training School Complex, Anushaktinagar, Mumbai 400094, Maharashtra (India); Sahu, Khageswar [Laser Biomedical Applications Section, Raja Ramanna Centre for Advanced Technology, Indore 452013, Madhya Pradesh (India)

2017-06-15

Infiltrating macrophages in tumor microenvironment, through their secreted cytokines and growth factors, regulate several processes of cancer progression such as cancer cell survival, proliferation, invasion, metastasis and angiogenesis. Recently, intercellular cytoplasmic bridges between cancer cells referred as tunneling nanotubes (TNTs) have been recognized as novel mode of intercellular communication between cancer cells. In this study, we investigated the effect of inflammatory mediators present in conditioned medium derived from macrophages on the formation of TNTs in breast adenocarcinoma cells MCF-7. Results show that treatment with macrophage conditioned medium (MφCM) not only enhanced TNT formation between cells but also stimulated the release of independently migrating viable cytoplasmic fragments, referred to as microplasts, from MCF-7 cells. Time lapse microscopy revealed that microplasts were released from parent cancer cells in extracellular space through formation of TNT-like structures. Mitochondria, vesicles and cytoplasm could be transferred from parent cell body to microplasts through connecting TNTs. The microplasts could also be resorbed into the parent cell body by retraction of the connecting TNTs. Microplast formation inhibited in presence cell migration inhibitor, cytochalasin-B. Notably by utilizing migratory machinery within microplasts, distantly located MCF-7 cells formed several TNT based intercellular connections, leading to formation of physically connected network of cells. Together, these results demonstrate novel role of TNTs in microplast formation, novel modes of TNT formation mediated by microplasts and stimulatory effect of MφCM on cellular network formation in MCF-7 cells mediated through enhanced TNT and microplast formation.

Using Time-Driven Activity-Based Costing as a Key Component of the Value Platform: A Pilot Analysis of Colonoscopy, Aortic Valve Replacement and Carpal Tunnel Release Procedures

Science.gov (United States)

Martin, Jacob A.; Mayhew, Christopher R.; Morris, Amanda J.; Bader, Angela M.; Tsai, Mitchell H.; Urman, Richard D.

2018-01-01

Background Time-driven activity-based costing (TDABC) is a methodology that calculates the costs of healthcare resources consumed as a patient moves along a care process. Limited data exist on the application of TDABC from the perspective of an anesthesia provider. We describe the use of TDABC, a bottom-up costing strategy and financial outcomes for three different medical-surgical procedures. Methods In each case, a multi-disciplinary team created process maps describing the care delivery cycle for a patient encounter using the TDABC methodology. Each step in a process map delineated an activity required for delivery of patient care. The resources (personnel, equipment and supplies) associated with each step were identified. A per minute cost for each resource expended was generated, known as the capacity cost rate, and multiplied by its time requirement. The total cost for an episode of care was obtained by adding the cost of each individual resource consumed as the patient moved along a clinical pathway. Results We built process maps for colonoscopy in the gastroenterology suite, calculated costs of an aortic valve replacement by comparing surgical aortic valve replacement (SAVR) versus transcatheter aortic valve replacement (TAVR) techniques, and determined the cost of carpal tunnel release in an operating room versus an ambulatory procedure room. Conclusions TDABC is central to the value-based healthcare platform. Application of TDABC provides a framework to identify process improvements for health care delivery. The first case demonstrates cost-savings and improved wait times by shifting some of the colonoscopies scheduled with an anesthesiologist from the main hospital to the ambulatory facility. In the second case, we show that the deployment of an aortic valve via the transcatheter route front loads the costs compared to traditional, surgical replacement. The last case demonstrates significant cost savings to the healthcare system associated with re

Does flexible tunnel drilling affect the femoral tunnel angle measurement after anterior cruciate ligament reconstruction?

Science.gov (United States)

Muller, Bart; Hofbauer, Marcus; Atte, Akere; van Dijk, C Niek; Fu, Freddie H

2015-12-01

To quantify the mean difference in femoral tunnel angle (FTA) as measured on knee radiographs between rigid and flexible tunnel drilling after anatomic anterior cruciate ligament (ACL) reconstruction. Fifty consecutive patients that underwent primary anatomic ACL reconstruction with a single femoral tunnel drilled with a flexible reamer were included in this study. The control group was comprised of 50 patients all of who underwent primary anatomic ACL reconstruction with a single femoral tunnel drilled with a rigid reamer. All femoral tunnels were drilled through a medial portal to ensure anatomic tunnel placement. The FTA was determined from post-operative anterior-to-posterior (AP) radiographs by two independent observers. A 5° difference between the two mean FTA was considered clinically significant. The average FTA, when drilled with a rigid reamer, was 42.0° ± 7.2°. Drilling with a flexible reamer resulted in a mean FTA of 44.7° ± 7.0°. The mean difference of 2.7° was not statistically significant. The intraclass correlation coefficient for inter-tester reliability was 0.895. The FTA can be reliably determined from post-operative AP radiographs and provides a useful and reproducible metric for characterizing femoral tunnel position after both rigid and flexible femoral tunnel drilling. This has implications for post-operative evaluation and preoperative treatment planning for ACL revision surgery. IV.

[Sustained-release progesterone vaginal suppositories 3-development and clinical feasibility testing].

Science.gov (United States)

Nakayama, Ayako; Yamaguchi, Naho; Ohno, Yukiko; Miyata, Chihiro; Kondo, Haruomi; Sunada, Hisakazu; Okamoto, Hirokazu

2013-01-01

  Although progesterone vaginal suppositories (hospital-formulated) are used for the treatment of infertility, their half-life is so short that multiple doses are required. In this study, we aimed to develop sustained-release vaginal suppositories suitable for clinical use which maintain an effective blood concentration by once-a-day treatment, and prepared 7 types of suppository containing the sustained-release progesterone tablets to characterize their sustained-release performance. We selected one candidate suppository among them, taking recovery rate, reproducibility, and hardness, as well as the sustained-release performance into consideration. The shell of the selected suppository is composed of VOSCO S-55 and progesterone for rapid release. The molded progesterone tablets for sustained release were embedded inside. The distribution of the weight and content of the suppository was limited, and the release rate of progesterone was significantly slower than that of a conventional progesterone suppository prepared in our hospital. The single-dose administration of the selected suppository to five healthy volunteers led to significant extension of the blood concentration. We also confirmed the rise of the basic value by multiple administration. The simulation comparison suggested that the blood progesterone concentration is controlled by once-a-day administration of the selected suppository better than twice-a-day administration of the conventional suppository. In conclusion, the sustained-release vaginal suppository prepared in this study was considered to be useful for clinical treatment.

Tunnel widening in anterior cruciate ligament reconstruction

DEFF Research Database (Denmark)

Clatworthy, M G; Annear, P; Bulow, J U

1999-01-01

We report a prospective series evaluating the incidence and degree of tunnel widening in a well-matched series of patients receiving a hamstring or patella tendon graft for anterior cruciate ligament (ACL) deficiency. We correlated tunnel widening with clinical factors, knee scores, KT-1000 and i...

Diagnostic utility of F waves in clinically diagnosed patients of carpal tunnel syndrome.

Science.gov (United States)

Joshi, Anand G; Gargate, Ashwini R

2013-01-01

Sensory nerve conduction velocity (SNCV) of median nerve measured across the carpal tunnel, difference between distal sensory latencies (DSLs) of median and ulnar nerves and difference between distal motor latencies (DMLs) of median and ulnar nerves are commonly used nerve conduction parameters for diagnosis of carpal tunnel syndrome (CTS). These are having high degree of sensitivity and specificity. Study of median nerve F-wave minimal latency (FWML) and difference between F-wave minimal latencies (FWMLs) of median and ulnar nerves have also been reported to be useful parameters for diagnosis of CTS. However, there is controversy regarding superiority of F-wave study for diagnosis of CTS. So the aim of present study was to compare sensitivity and specificity of median FWML and difference between FWMLs of median and ulnar nerves with that of above mentioned electrophysiological parameters and to find out which parameters are having more sensitivity and specificity, for early diagnosis of CTS. Median and ulnar nerves sensory and motor conduction, median and ulnar nerves F-wave studies were carried out bilaterally in 125 clinically diagnosed patients of carpal tunnel syndrome. These parameters were also studied in 45 age matched controls. Difference between DSLs of median and ulnar nerves, median SNCV and difference between DMLs of median and ulnar nerves were having highest sensitivity and specificity while median FWML and difference between FWMLs of median and ulnar nerves was having lowest sensitivity and specificity for diagnosis of CTS. So in conclusion F-wave study is not superior parameter for diagnosis of CTS.

Data Quality Objectives Report for the 115-B Gas Tunnel

International Nuclear Information System (INIS)

Bauer, R.G.

1998-05-01

This workbook assisted the Data Quality Objectives Team in implementing the Data Quality Objectives Process through the use of a template which lists the important elements of the DQO. The completion of this workbook is a required element of the BHI-EE-01, Procedure 1.2, 'Data Quality Objectives.' The objective of this project is to define the sampling and analysis requirements for isolation and decontamination and decommissioning release of the 115- B Gas Tunnel. The 115-B Gas Tunnel is an underground concrete pipe tunnel that houses piping used to recirculate helium gas between the 105-B Reactor Building and the 115-B/C Gas Recirculation System

Tunnel backfill erosion by dilute water

International Nuclear Information System (INIS)

Olin, M.

2014-03-01

The goal was to estimate smectite release from tunnel backfill due to dilute groundwater pulse during post glacial conditions. The plan was to apply VTT's two different implementations (BESW D and BESW S ) of well-known model of Neretnieks et al. (2009). It appeared difficult to produce repeatable results using this model in COMSOL 4.2 environment, therefore a semi-analytical approximate approach was applied, which enabled to take into account both different geometry and smectite content in tunnel backfill as compared to buffer case. The results are quite similar to buffer results due to the decreasing effect of smaller smectite content and the increasing effect of larger radius. (orig.)

Tunnel backfill erosion by dilute water

Energy Technology Data Exchange (ETDEWEB)

Olin, M. [VTT Technical Research Centre of Finland, Espoo (Finland)

2014-03-15

The goal was to estimate smectite release from tunnel backfill due to dilute groundwater pulse during post glacial conditions. The plan was to apply VTT's two different implementations (BESW{sub D} and BESW{sub S}) of well-known model of Neretnieks et al. (2009). It appeared difficult to produce repeatable results using this model in COMSOL 4.2 environment, therefore a semi-analytical approximate approach was applied, which enabled to take into account both different geometry and smectite content in tunnel backfill as compared to buffer case. The results are quite similar to buffer results due to the decreasing effect of smaller smectite content and the increasing effect of larger radius. (orig.)

Treatment of Carpal Tunnel Syndrome in pregnancy with Polarized Polychromatic Non-coherent Light (Bioptron Light): A Preliminary, Prospective, Open Clinical Trial.

Science.gov (United States)

Dimitrios, Stasinopoulos; Stasinopoulos, Loannis

2017-12-31

The aim of this trial was to assess the efficacy of polarized polychromatic noncoherent light (Bioptron light) in the treatment of Carpal Tunnel Syndrome (CTS) in pregnancy. An uncontrolled experimental study was conducted in pregnant patients with CTS who visited our clinic from January 2006 to January 2010. Bioptron light (480-3400 nm; 95% polarization; 40 mW/cm 2 ; and 2.4 J/cm 2 ) was administered perpendicular to the carpal tunnel area. The irradiation time for each session was 6 min at an operating distance of 5-10 cm from the carpal tunnel area, twice each day, five days per week for 2 weeks. Pain and paraesthesia using a visual analogue scale (VAS) and finger pinch strength were evaluated at the end of treatment (week 2) and 1-month (week 6) after the end of treatment. The Student'sttest was used and p values Bioptron light is a reliable, safe, and effective treatment option in pregnant patients with CTS. Controlled clinical trials are needed to establish the absolute and relative effectiveness of this intervention.

Closure Report for Corrective Action Unit 481: Area 12 T-Tunnel Conditional Release Storage Yard, Nevada Test Site, Nevada

International Nuclear Information System (INIS)

2008-01-01

Corrective Action Unit (CAU) 481 is identified in the Federal Facility Agreement and Consent Order (FFACO) as Area 12 T-Tunnel Conditional Release Storage Yard. CAU 481 is located in Area 12 of the Nevada Test Site, which is approximately 65 miles northwest of Las Vegas, Nevada. This CAU consists of one Corrective Action Site (CAS), CAS 12-42-05, Housekeeping Waste. CAU 481 closure activities were conducted by the Defense Threat Reduction Agency from August 2007 through July 2008 according to the FFACO and Revision 3 of the Sectored Clean-up Work Plan for Housekeeping Category Waste Sites. Closure activities included removal and disposal of construction debris and low-level waste. Drained fluids, steel, and lead was recycled as appropriate. Waste generated during closure activities was appropriately managed and disposed.

Macrophage conditioned medium induced cellular network formation in MCF-7 cells through enhanced tunneling nanotube formation and tunneling nanotube mediated release of viable cytoplasmic fragments.

Science.gov (United States)

Patheja, Pooja; Sahu, Khageswar

2017-06-15

Infiltrating macrophages in tumor microenvironment, through their secreted cytokines and growth factors, regulate several processes of cancer progression such as cancer cell survival, proliferation, invasion, metastasis and angiogenesis. Recently, intercellular cytoplasmic bridges between cancer cells referred as tunneling nanotubes (TNTs) have been recognized as novel mode of intercellular communication between cancer cells. In this study, we investigated the effect of inflammatory mediators present in conditioned medium derived from macrophages on the formation of TNTs in breast adenocarcinoma cells MCF-7. Results show that treatment with macrophage conditioned medium (MɸCM) not only enhanced TNT formation between cells but also stimulated the release of independently migrating viable cytoplasmic fragments, referred to as microplasts, from MCF-7 cells. Time lapse microscopy revealed that microplasts were released from parent cancer cells in extracellular space through formation of TNT-like structures. Mitochondria, vesicles and cytoplasm could be transferred from parent cell body to microplasts through connecting TNTs. The microplasts could also be resorbed into the parent cell body by retraction of the connecting TNTs. Microplast formation inhibited in presence cell migration inhibitor, cytochalasin-B. Notably by utilizing migratory machinery within microplasts, distantly located MCF-7 cells formed several TNT based intercellular connections, leading to formation of physically connected network of cells. Together, these results demonstrate novel role of TNTs in microplast formation, novel modes of TNT formation mediated by microplasts and stimulatory effect of MɸCM on cellular network formation in MCF-7 cells mediated through enhanced TNT and microplast formation. Copyright © 2017 Elsevier Inc. All rights reserved.

Tunneling technologies for the collider ring tunnels

International Nuclear Information System (INIS)

Frobenius, P.

1989-01-01

The Texas site chosen for the Superconducting Super Collider has been studied, and it has been determined that proven, conventional technology and accepted engineering practice are suitable for constructing the collider tunnels. The Texas National Research Laboratory Commission report recommended that two types of tunneling machines be used for construction of the tunnels: a conventional hard rock tunnel boring machine (TBM) for the Austin chalk and a double shielded, rotary TBM for the Taylor marl. Since the tunneling machines usually set the pace for the project, efficient planning, operation, and coordination of the tunneling system components will be critical to the schedule and cost of the project. During design, tunneling rate prediction should be refined by focusing on the development of an effective tunneling system and evaluating its capacity to meet or exceed the required schedules. 8 refs., 13 figs

High-resolution sonography in carpal tunnel syndrome

International Nuclear Information System (INIS)

Solbiati, L.; De Pra, L.; Rizzatto, G.; Derchi, L.E.

1986-01-01

Carpal tunnel syndrome, caused by the compression on the median nerve under the transverse carpal ligament, has multiple causes and clinical presentations. One hundred eighteen patients with carpal tunnel sydrome underwent high-resolution US which demonstrated unpalpable cystic masses in 25 patients (lobulated stalked synovial cysts in 19 and retrotendinous cysts in six, all confirmed at surgery), and diffuse thickening and decreased echogenicity of the tendon sheaths in 87 patients, suggesting tenosynovitis (confirmed at surgery in 64). In six patients simple encasement of muscle bellies in the carpal tunnel was shown. US can delineate the cause of carpal tunnel syndrome, suggest the need for surgery, and aid the surgeon in locating the lesion to be removed

Transverse Carpal Ligament and Forearm Fascia Release for the Treatment of Carpal Tunnel Syndrome Change the Entrance Angle of Flexor Tendons to the A1 Pulley: The Relationship between Carpal Tunnel Surgery and Trigger Finger Occurence

Directory of Open Access Journals (Sweden)

Nazım Karalezli

2013-01-01

Full Text Available Purpose. The appearance of trigger finger after decompression of the carpal tunnel without a preexisting symptom has been reported in a few articles. Although, the cause is not clear yet, the loss of pulley action of the transverse carpal ligament has been accused mostly. In this study, we planned a biomechanical approach to fresh cadavers. Methods. The study was performed on 10 fresh amputees of the arm. The angles were measured with (1 the transverse carpal ligament and the distal forearm fascia intact, (2 only the transverse carpal ligament incised, (3 the distal forearm fascia incised to the point 3 cm proximal from the most proximal part of the transverse carpal ligament in addition to the transverse carpal ligament. The changes between the angles produced at all three conditions were compared to each other. Results. We saw that the entrance angle increased in all of five fingers in an increasing manner from procedure 1 to 3, and it was seen that the maximal increase is detected in the middle finger from procedure 1 to procedure 2 and the minimal increase is detected in little finger. Discussion. Our results support that transverse carpal ligament and forearm fascia release may be a predisposing factor for the development of trigger finger by the effect of changing the enterance angle to the A1 pulley and consequently increase the friction in this anatomic area. Clinical Relevance. This study is a cadaveric study which is directly investigating the effect of a transverse carpal ligament release on the enterance angle of flexor tendons to A1 pulleys in the hand.

Validation of the Boston Carpal Tunnel Questionnaire in Russia

Directory of Open Access Journals (Sweden)

D. G. Yusupova

2018-01-01

Full Text Available International scales and questionnaires have become widespread in Russian neurology. Validation is a procedure of top priority necessary before applying this kind of diagnostic instrument in Russian-speaking population. In this article, validation of the Boston Carpal Tunnel Questionnaire (BCTQ intended for patients with this disease is described. Use of validated Russian version would allow to objectively evaluate severity of clinical manifestations of carpal tunnel syndrome and follow patient dynamics. We present the official BCTQ version recommended for use in Russia, as well as data that showed high sensitivity and reliability of this instrument for clinical evaluation of carpal tunnel syndrome.

HFSB-seeding for large-scale tomographic PIV in wind tunnels

Science.gov (United States)

Caridi, Giuseppe Carlo Alp; Ragni, Daniele; Sciacchitano, Andrea; Scarano, Fulvio

2016-12-01

A new system for large-scale tomographic particle image velocimetry in low-speed wind tunnels is presented. The system relies upon the use of sub-millimetre helium-filled soap bubbles as flow tracers, which scatter light with intensity several orders of magnitude higher than micron-sized droplets. With respect to a single bubble generator, the system increases the rate of bubbles emission by means of transient accumulation and rapid release. The governing parameters of the system are identified and discussed, namely the bubbles production rate, the accumulation and release times, the size of the bubble injector and its location with respect to the wind tunnel contraction. The relations between the above parameters, the resulting spatial concentration of tracers and measurement of dynamic spatial range are obtained and discussed. Large-scale experiments are carried out in a large low-speed wind tunnel with 2.85 × 2.85 m2 test section, where a vertical axis wind turbine of 1 m diameter is operated. Time-resolved tomographic PIV measurements are taken over a measurement volume of 40 × 20 × 15 cm3, allowing the quantitative analysis of the tip-vortex structure and dynamical evolution.

Final report on the Controlled Cold Helium Spill Test in the LHC tunnel at CERN

CERN Document Server

Dufay-Chanat, L; Casas-Cubillos, J; Chorowski, M; Grabowski, M; Jedrusyna, A; Lindell, G; Nonis, M; Koettig, T; Vauthier, N; van Weelderen, R; Winkler, T

2015-01-01

The 27 km circumference LHC underground tunnel is a space in which the helium cooled LHC magnets are installed. The vacuum enclosures of the superconducting magnets are protected by over-pressure safety relief devices that open whenever cold helium escapes either from the magnet cold enclosure or from the helium supply headers, into this vacuum enclosure. A 3-m long no stay zone around these devices is defined based on scale model studies, protecting the personnel against cold burns or asphyxia caused by such a helium release event. Recently, several simulation studies have been carried out modelling the propagation of the helium/air mixture, resulting from the opening of such a safety device, along the tunnel. The released helium flows vary in the range between 1 kg/s and 0.1 kg/s. To validate these different simulation studies, real life mock-up tests have been performed inside the LHC tunnel, releasing helium flow rates of 1 kg/s, 0.3 kg/s and 0.1 kg/s. For each test, up to 1000 liters of liquid helium wer...

Swimming Performance of Adult Asian Carp: Field Assessment Using a Mobile Swim Tunnel

Science.gov (United States)

2016-08-01

ERDC/TN ANSRP-16-1 August 2016 Approved for public release; distribution is unlimited. Swimming Performance of Adult Asian Carp: Field...Assessment Using a Mobile Swim Tunnel by Jan Jeffrey Hoover, Jay A. Collins, Alan W. Katzenmeyer, and K. Jack Killgore PURPOSE: Empirical swim speed...test in traditional laboratory swim tunnels. Biologists from the Engineer Research and Development Center (ERDC) Environmental Laboratory (EL), with

A flow visualization study of spore release using a wind tunnel-mounted laser light sheet

International Nuclear Information System (INIS)

Davis, J.M.; Eisner, A.D.; Wiener, R.W.; Main, C.E.

1997-01-01

A phase Doppler anemometry system in combination with a laser light sheet was used in a low-speed recirculating wind tunnel to examine the flow field around an individual leaf. Turbulence similar to that encountered near the surface of the earth in a neutral stability boundary layer was generated using a grid at the upwind end of the wind tunnel test section. Individual healthy and diseased plant leaves were introduced into the tunnel with the leaf tip pointing downwind. The Mie-scattered radiation from the spores departing the diseased leaf was captured on videotape. Image processing software was used to enhance the visual quality of the individual frames from the videotape and to make spore velocity calculations. Three main vortex regions around the leaf were identified. The importance of these regions to the separation of the spores from the leaf surface and their subsequent downwind movement was analyzed

Clinical observation of Ahmed glaucoma valve implantation for refractory glaucoma by directly puncturing the sclerotic tunnel

Directory of Open Access Journals (Sweden)

Zhi-Ke Xu

2015-02-01

Full Text Available AIM: To observe the clinic effects and complication of Ahmed glaucoma valve(AGVimplantation in refractory glaucoma by using the 23G syringe needle direct puncture the sclerotic tunnel.METHODS: Forty-four cases(44 eyesof refractory glaucoma underwent AGV implantation by useing the 23G syringe needle direct puncture the sclerotic tunnel. The intraocular pressure(IOP, visual acuity, and complication of post-operation were contrasted with those of pre-operation. RESULTS:The success rate was 84.1%, the mean preoperative IOP in research group was 52.1±10.1mmHg, and the last follow up mean IOP was 15.6±6.9mmHg. Compared with the preoperative visual acuity, 11 eyes increased, 27 eyes had no changes and 6 eyes decreased. The main post-operative complications included shallow anterior chamber(4 eyes, choroidal detachment(3 eyes, drainage tube shift(1 eye, hyphema(6 eyes, drainage tube blockage(1 eye, expulsive choroidal hemorrhage(1 eye, and fiber wrap of drainage tray(5 eyes.CONCLUSION: AGV implantation by direct puncture the sclerotic tunnel is feasible and easy. It avoids of making sclerotic petal and the xenogenic sclera transplanting, simplified the operation technique, prevent the leakage of around tube. The shallow anterior chamber rate is lower. It is an effective procedure for refractory glaucoma.

Numerical investigation of potential stratification caused by a cryogenic helium spill inside a tunnel

Science.gov (United States)

Sinclair, Cameron; Malecha, Ziemowit; Jedrusyna, Artur

2018-04-01

The sudden release of cryogenic fluid into an accelerator tunnel can pose a significant health and safety risk. For this reason, it is important to evaluate the consequences of such a spill. Previous publications concentrated on either Oxygen Deficiency Hazard or the evaluation of mathematical models using experimental data. No studies to date have focussed on the influence of cryogen inlet conditions on flow development. In this paper, the stratification behaviour of low-temperature helium released into an air-filled accelerator tunnel is investigated for varying helium inlet diameters. A numerical model was constructed using the OpenFOAM Toolbox of a generalised 3D geometry, with similar hydraulic characteristics to the CERN and SLAC tunnels. This model has been validated against published experimental and numerical data. A dimensionless parameter, based on Bakke number, was then determined for the onset of stratification, taking into account the helium inlet diameter; a dimensionless parameter for the degree of stratification was also employed. The simulated flow behaviour is described in terms of these dimensionless parameters, as well as the temperature and oxygen concentration at various heights throughout the tunnel.

Review of evolution of tunnel position in anterior cruciate ligament reconstruction.

Science.gov (United States)

Rayan, Faizal; Nanjayan, Shashi Kumar; Quah, Conal; Ramoutar, Darryl; Konan, Sujith; Haddad, Fares S

2015-03-18

Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established.

The influence of vehicular obstacles on longitudinal ventilation control in tunnel fires

DEFF Research Database (Denmark)

Alva, Wilson Ulises Rojas; Jomaas, Grunde; Dederichs, Anne

2017-01-01

The effect of the vehicular blockage in a tunnel under longitudinal ventilation smoke control was systematically studied using a small-scale tunnel (1:30 of a standard tunnel section) with a helium-air mixture as the buoyant plume. The experimental results showed excellent agreement with full......-scale data and reference correlations from former studies. When there are vehicular obstacles in the tunnel, the critical velocity decreased as a function of the blockage ratio. Notwithstanding, it was found that the relative size of the vehicular obstacle and the relative location of the fire source can...... and upper regimes of the dimensionless heat release rate, where the current data was compared against data from other studies. The method and experimental set-up proved their ability to reproduce several phenomena and thus also their capability to supply relevant and valuable information on the effect...

Addressing student models of energy loss in quantum tunnelling

International Nuclear Information System (INIS)

Wittmann, Michael C; Morgan, Jeffrey T; Bao Lei

2005-01-01

We report on a multi-year, multi-institution study to investigate students' reasoning about energy in the context of quantum tunnelling. We use ungraded surveys, graded examination questions, individual clinical interviews and multiple-choice exams to build a picture of the types of responses that students typically give. We find that two descriptions of tunnelling through a square barrier are particularly common. Students often state that tunnelling particles lose energy while tunnelling. When sketching wavefunctions, students also show a shift in the axis of oscillation, as if the height of the axis of oscillation indicated the energy of the particle. We find inconsistencies between students' conceptual, mathematical and graphical models of quantum tunnelling. As part of a curriculum in quantum physics, we have developed instructional materials designed to help students develop a more robust and less inconsistent picture of tunnelling, and present data suggesting that we have succeeded in doing so

Tunneling decay of false domain walls: The silence of the lambs

Energy Technology Data Exchange (ETDEWEB)

Haberichter, Mareike, E-mail: M.Haberichter@kent.ac.uk [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); School of Mathematics, Statistics and Actuarial Science, University of Kent, Canterbury CT2 7NF (United Kingdom); MacKenzie, Richard, E-mail: richard.mackenzie@umontreal.ca; Ung, Yvan, E-mail: klingon-ecology@hotmail.com [Groupe de Physique des Particules, Département de Physique, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montreal, Québec H3C 3J7 (Canada); Paranjape, M. B., E-mail: paranj@lps.umontreal.ca [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Wilberforce Road, Cambridge CB3 0WA (United Kingdom); Groupe de Physique des Particules, Département de Physique, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montreal, Québec H3C 3J7 (Canada); St. John’s College, University of Cambridge, Cambridge CB2 1TP (United Kingdom)

2016-04-15

We study the decay of “false” domain walls, that is, metastable states of the quantum theory where the true vacuum is trapped inside the wall with the false vacuum outside. We consider a theory with two scalar fields, a shepherd field and a field of sheep. The shepherd field serves to herd the solitons of the sheep field so that they are nicely bunched together. However, quantum tunnelling of the shepherd field releases the sheep to spread out uncontrollably. We show how to calculate the tunnelling amplitude for such a disintegration.

Tunneling decay of false domain walls: The silence of the lambs

International Nuclear Information System (INIS)

Haberichter, Mareike; MacKenzie, Richard; Ung, Yvan; Paranjape, M. B.

2016-01-01

We study the decay of “false” domain walls, that is, metastable states of the quantum theory where the true vacuum is trapped inside the wall with the false vacuum outside. We consider a theory with two scalar fields, a shepherd field and a field of sheep. The shepherd field serves to herd the solitons of the sheep field so that they are nicely bunched together. However, quantum tunnelling of the shepherd field releases the sheep to spread out uncontrollably. We show how to calculate the tunnelling amplitude for such a disintegration.

Conservative therapeutic management of carpal tunnel syndrome

Directory of Open Access Journals (Sweden)

Roberto Sérgio Martins

Full Text Available ABSTRACT Carpal tunnel syndrome is the most prevalent nerve compression and can be clinically or surgically treated. In most cases, the first therapeutic alternative is conservative treatment but there is still much controversy regarding the most effective modality of this treatment. In this study, we critically evaluated the options of conservative treatment for carpal tunnel syndrome, aiming to guide the reader through the conventional options used in this therapy.

Restoring proximal caries lesions conservatively with tunnel restorations.

Science.gov (United States)

Chu, Chun-Hung; Mei, May L; Cheung, Chloe; Nalliah, Romesh P

2013-07-30

The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED) and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations.

Tunneling time, the Hartman effect, and superluminality: A proposed resolution of an old paradox

International Nuclear Information System (INIS)

Winful, Herbert G.

2006-01-01

The issue of tunneling time is replete with controversy and paradoxes. The controversy stems from the fact that many tunneling time definitions seem to predict superluminal tunneling velocities. One prediction, termed the Hartman effect, states that the tunneling time becomes independent of barrier length for thick enough barriers, ultimately resulting in unbounded tunneling velocities. Experiments done with 'single photons', classical light waves, and microwaves all show this apparent superluminality. The origin of these paradoxical effects has been a mystery for decades. In this article, we review the history of tunneling times starting with the early work of MacColl, Hartman, and Wigner. We discuss some of the tunneling time definitions, with particular emphasis on the phase time (also known as the group delay or Wigner time) and the dwell time. The key experiments are reviewed. We then discuss our recent work, which suggests that the group delay in tunneling is not a transit time as has been assumed for decades. It is, in reality, a lifetime and hence should not be used to assign a speed of barrier traversal. We show how this new understanding along with the concept of energy storage and release resolves all the outstanding tunneling time paradoxes

Tunnel - history of

International Nuclear Information System (INIS)

1998-11-01

This book introduces history of tunnel in ancient times, the middle ages and modern times, survey of tunnel and classification of bedrock like environment survey of position, survey of the ground, design of tunnel on basic thing of the design, and design of tunnel of bedrock, analysis of stability of tunnel and application of the data, construction of tunnel like lattice girder and steel fiber reinforced shot crete, and maintenance control and repair of tunnel.

Mini transverse versus longitudinal incision in carpal tunnel syndrome

International Nuclear Information System (INIS)

Korkmaz, M.; Cepoglu, M.C.

2013-01-01

Objective: To evaluate the effectiveness of mini-transverse compared with mini-longitudinal incision for carpal tunnel release (CTR) with reference to postoperative functional capacity, symptom severity and complication rate. Study Design: Analytical study. Place and Duration of Study: Cumhuriyet University Medical Faculty, Department of Orthopaedics, Tokat State Hospital, Department of Orthopaedics and Medical Park Tokat Hospital, Department of Neurosurgery, from January 2007 to January 2009. Methodology: This study included 93 hands of 79 patients with carpal tunnel syndrome (CTS), which were operated between 2007 and 2009. Patients were divided according to incision types into Group-1 (undergoing mini-longitudinal incision) and Group-2 (undergoing mini-transverse incision). Patients were evaluated initially and at 3 weeks after treatment according to symptom severity and functional status of Boston Questionnaire (BQ). Demographic and clinical data were analyzed and compared statistically between two groups. Results: Statistically significant differences were observed in BQ symptom and functional scores between the pre- and postoperative period (p < 0.0001). BQ symptom and functional scores at postoperative period were better in Group-1 than Group-2 (p = 0.044 and p = 0.023 respectively). The scar hypersensitivity (p = 0.258) and tenderness (p = 1.00) associated with the incision sites were not statistically different. Conclusion: Longitudinal incision is more effective on symptom and functional conditions than transverse incision. However, there was less scar formation with transverse incision. (author)

Surgery without papilla incision: tunneling flap procedures in plastic periodontal and implant surgery.

Science.gov (United States)

Zuhr, Otto; Rebele, Stephan F; Cheung, Stefani L; Hürzeler, Markus B

2018-06-01

Diverse clinical advancements, together with some relevant technical innovations, have led to an increase in popularity of tunneling flap procedures in plastic periodontal and implant surgery in the recent past. This trend is further promoted by the fact that these techniques have lately been introduced to a considerably expanded range of indications. While originally described for the treatment of gingival recession-type defects, tunneling flap procedures may now be applied successfully in a variety of clinical situations in which augmentation of the soft tissues is indicated in the esthetic zone. Potential clinical scenarios include surgical thickening of thin buccal gingiva or peri-implant mucosa, alveolar ridge/socket preservation and implant second-stage surgery, as well as soft-tissue ridge augmentation or pontic site development. In this way, tunneling flap procedures developed from a technique, originally merely intended for surgical root coverage, into a capacious surgical conception in plastic periodontal and implant surgery. The purpose of this article is to provide a comprehensive overview on tunneling flap procedures, to introduce the successive development of the approach along with underlying ideas on surgical wound healing and to present contemporary clinical scenarios in step-by-step photograph-illustrated sequences, which aim to provide clinicians with guidance to help them integrate tunneling flap procedures into their daily clinical routine. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Typical Underwater Tunnels in the Mainland of China and Related Tunneling Technologies

Directory of Open Access Journals (Sweden)

Kairong Hong

2017-12-01

Full Text Available In the past decades, many underwater tunnels have been constructed in the mainland of China, and great progress has been made in related tunneling technologies. This paper presents the history and state of the art of underwater tunnels in the mainland of China in terms of shield-bored tunnels, drill-and-blast tunnels, and immersed tunnels. Typical underwater tunnels of these types in the mainland of China are described, along with innovative technologies regarding comprehensive geological prediction, grouting-based consolidation, the design and construction of large cross-sectional tunnels with shallow cover in weak strata, cutting tool replacement under limited drainage and reduced pressure conditions, the detection and treatment of boulders, the construction of underwater tunnels in areas with high seismic intensity, and the treatment of serious sedimentation in a foundation channel of immersed tunnels. Some suggestions are made regarding the three potential great strait-crossing tunnels—the Qiongzhou Strait-Crossing Tunnel, Bohai Strait-Crossing Tunnel, and Taiwan Strait-Crossing Tunnel—and issues related to these great strait-crossing tunnels that need further study are proposed. Keywords: Underwater tunnel, Strait-crossing tunnel, Shield-bored tunnel, Immersed tunnel, Drill and blast

Performing wind-tunnel modeling for better management of near-field risks

International Nuclear Information System (INIS)

Huang, Ju-Chrong; Weber, A.H.

1992-01-01

All industrial complexes must be able to demonstrate that air pollutant concentrations from normal and accidental releases are within the bounds of stringent acceptance criteria. The offsite concentrations are comparatively easy to compute with the standard Gaussian models. By contrast, the onsite (in particular, near-field) concentrations can be more complex since the wind flows can interact with various structures in complex ways to create regions of relatively high local concentrations. Three methods can be used to predict the air pollutant concentrations: (1) mathematical models, (2) field experiments, and (3) fluid models (wind-tunnel testing). The complex flow in the vicinity of buildings is not amenable to simple mathematical generalizations. Field experiments cannot encompass the wind spectrum of meteorological conditions in the time generally allotted. Wind tunnel testing works best where numerical models fail and field testing is not applicable. This paper covers the following aspects related to the wind-tunnel modeling studies: (1) planning strategies; (2) types of wind-tunnel modeling studies flow visualization and concentration measurement experiments; (3) highlights (video tape show) of the wind tunnel experiments; (4) technical challenges; and (5) various applications

Direct, coherent and incoherent intermediate state tunneling and scanning tunnel microscopy (STM)

International Nuclear Information System (INIS)

Halbritter, J.

1997-01-01

Theory and experiment in tunneling are still qualitative in nature, which hold true also for the latest developments in direct-, resonant-, coherent- and incoherent-tunneling. Those tunnel processes have recently branched out of the field of ''solid state tunnel junctions'' into the fields of scanning tunnel microscopy (STM), single electron tunneling (SET) and semiconducting resonant tunnel structures (RTS). All these fields have promoted the understanding of tunneling in different ways reaching from the effect of coherence, of incoherence and of charging in tunneling, to spin flip or inelastic effects. STM allows not only the accurate measurements of the tunnel current and its voltage dependence but, more importantly, the easy quantification via the (quantum) tunnel channel conductance and the distance dependence. This new degree of freedom entering exponentially the tunnel current allows an unique identification of individual tunnel channels and their quantification. In STM measurements large tunnel currents are observed for large distances d > 1 nm explainable by intermediate state tunneling. Direct tunneling with its reduced tunnel time and reduced off-site Coulomb charging bridges distances below 1 nm, only. The effective charge transfer process with its larger off-site and on-site charging at intermediate states dominates tunnel transfer in STM, biology and chemistry over distances in the nm-range. Intermediates state tunneling becomes variable range hopping conduction for distances larger than d > 2 nm, for larger densities of intermediate states n 1 (ε) and for larger temperatures T or voltages U, still allowing high resolution imaging

Radial tunnel syndrome. Findings and treatment in 17 patients

Directory of Open Access Journals (Sweden)

Gustavo Alberto Breglia

2015-05-01

Full Text Available Backround Radial tunnel syndrome is a condition secondary to the intermittent entrapment of the posterior interosseous nerve between superficial and deep mass of short supinator adjacent structures, such as vessels and fascias. The purpose of this study was to identify the anatomical structures that produce the eventual compression, to establish and communicate the differences in the subjective pain perception before and after the release of the posterior interosseous nerve in the radial tunnel. Method Between 2009 and 2014, 17 patients underwent surgical treatment by posterior interosseous nerve release. We used the approach between the first external radial and brachioradialis. Patients were assessed by visual analogue scale for pain intensity before surgery and at week 6, and according to the Roles and Maudsley functional criteria. Results The causes of posterior interosseous nerve compression were fibrous band of short supinator (arcade of Frohse (7 cases, recurrent vessels (4 cases, compression by the mass of the superficial portion of the short supinator muscle (2 cases and secondary compression by extensor carpi radialis brevis tendon (4 cases. Results were excellent (4 patients, good (10 patients and fair (3 patients. Patients treated through the Labor Risk Insurance had worse outcomes than those who were not covered by this system. Conclusions Radial tunnel syndrome is a condition that must be taken into account when there is refractory lateral epicondylalgia. This disease has a marked effect in patients with labor conflict, which may bias the outcome of treatment.

Root coverage with connective tissue graft associated with coronally advanced flap or tunnel technique: a randomized, double-blind, mono-centre clinical trial

NARCIS (Netherlands)

Azaripour, Adriano; Kissinger, Maren; Farina, Vittorio Siro Leone; van Noorden, Cornelis J. F.; Gerhold-Ay, Aslihan; Willershausen, Brita; Cortellini, Pierpaolo

2016-01-01

Aim: The aim of this randomized clinical trial was to compare the coronally advanced flap (CAF) with the modified microsurgical tunnel technique (MMTT) for treatment of Miller class I and II recessions. Material and Methods: Forty patients with 71 gingival recessions were recruited and randomly

The value of MRI iniIdiopathic tarsal tunnel syndrome by measuring the cross-sectional area of tarsal tunnel

Energy Technology Data Exchange (ETDEWEB)

Kim, Min Jung; Jeong, Yu Mi; Lee, Sheen Woo; Choi Seung; Kim, Jeong Ho; Park, Hong Gi [Gachon University, Gil Hospital, Incheon (Korea, Republic of)

2015-03-15

The purpose of this study was to evaluate the use of MRI as a diagnostic test in tarsal tunnel syndrome. There are no published reports with this aim and no diagnostic standard for idiopathic tarsal tunnel syndrome (TTS) using imaging modalities. We retrospectively searched our Picture Archiving and Communication System data and medical records to identify patients who were clinically and electomyographically diagnosed with idiopathic TTS without space-occupying lesion on MRI. Twenty five patients were included in the patient group. Another twenty-five patients who underwent ankle MRI for Achilles tendon disease were selected and included in the control group. Cross-sectional areas (CSA) of tarsal tunnel were manually measured independently by two radiologists who were blinded to clinical and surgical results, using three-dimensional reconstruction software in our hospital. Measurements were done on axial images at three levels (level 1, tibiotalar joint level; level 2, medial malleolar tip level; level 3, sustentaculum tali level). Patient and control group data were statistically analyzed by the Mann-Whitney test. The mean values of CSA at levels 1, 2, and 3 of the tarsal tunnel were 87.8 mm2, 98.2 mm2, and 105.2 mm2, respectively in the patient group; and 100.0 mm2, 113.8 mm2, and 127.9 mm2 in the control group, respectively, in reader 1; and 86.2 mm2, 97.6 mm2, 105.2 mm2, respectively in the patient group; and 99.7 mm2, 112.3 mm2, 124.4 mm2, respectively, in the control group, in reader 2. The mean CSA in the patient group was significantly less than that of the control group at all three levels (p < 0.05). Intra-class correlation coefficient value between reader 1 and reader 2 were 0.98 in group 1, and 0.97 in group 2, respectively. MRI can be helpful in the assessment of idiopathic tarsal tunnel syndrome. CSA measurements of tarsal tunnel at each level may predict TTS even though there are no space occupying lesions in the tarsal tunnel on MRI.

Potential airborne release from soil-working operations in a contaminated area

International Nuclear Information System (INIS)

Sutter, S.L.

1980-08-01

Experiments were performed to provide an indication of how much material could be made airborne during soil-working operations in a contaminated area. Approximately 50 kg of contaminated soil were collected, dried, and mixed, and particle size distribution and 137 Cs content were characterized. In four experiments performed in a 2 ft x 2 ft wind tunnel at the Radioactive Aerosol Release Test Facility, soil was pumped into an airstream moving at 3.2, 10.4, 15.2, and 20 mph. These experiments were designed to maximize airborne releases by fluidizing the soil as it was pumped into the wind tunnel. Thus the airborne releases should represent upper limit values for soil-working operations. Airborne concentration and particle size samples were collected and all of the material deposited downstream was collected to calculate a mass balance. The fraction airborne was calculated using these measurements

On the formation of the tunnel valleys of the southern Laurentide ice sheet

Science.gov (United States)

Hooke, R. LeB; Jennings, C.E.

2006-01-01

Catastrophic releases of meltwater, produced by basal melting and stored for decades in subglacial reservoirs at high pressure, may have been responsible for eroding the broad, deep tunnel valleys that are common along the margins of some lobes of the southern Laurentide ice sheet. We surmise that these releases began when the high water pressure was transmitted to the margin through the substrate. The water pressure in the substrate at the margin would then have been significantly above the overburden pressure, leading to sapping failure. Headward erosion of a conduit in the substrate (piping) could then tap the stored water, resulting in the outburst. In some situations, development of a siphon may have lowered the reservoir below its overflow level, thus tapping additional water. Following the flood, the seal could have reformed and the reservoir refilled, setting up conditions for another outburst. Order of magnitude calculations suggest that once emptied, a subglacial reservoir could refill in a matter of decades. The amount of water released during several outbursts appears to be sufficient to erode a tunnel valley. We think that tunnel valleys are most likely to have formed in this way where and when the glacier margin was frozen to the bed and permafrost extended from the glacier forefield several kilometers back under the glacier, as reservoirs would then have been larger and more common, and the seal more robust and more likely to reform after an outburst. ?? 2006 Elsevier Ltd. All rights reserved.

Clinicomicrobiological characteristics and treatment outcome of sclerocorneal tunnel infection.

Science.gov (United States)

Roy, Aravind; Sahu, Srikant K; Padhi, Tapas R; Das, Sujata; Sharma, Savitri

2012-07-01

To analyze the clinical presentation, microbiological evaluation, and management of post-cataract surgery sclerocorneal tunnel infection. This is a retrospective chart review of 11 patients with sclerocorneal tunnel infection after cataract surgery, managed between November 2006 and October 2009. The clinical characteristics and treatment outcomes were analyzed. All patients presented within 1 to 10 weeks of primary surgery. The presenting visual acuity ranged from hand motions to 20/50. Ten of 11 patients had sclerocorneal involvement, and 4 patients had associated endophthalmitis. The causative organisms were fungus (n = 6), bacteria (n = 4), or both (n = 1). Deroofing of the tunnel and sclerocorneal patch graft was done in 4 patients. Intensive medication was administered to all patients. The final visual acuity ranged from light perception to 20/50 at a mean follow-up of 119 days (median, 66 days; range, 2-357 days). Five patients had ≥20/100 vision. The mean interval between presentation to resolution of infiltrate and formation of peripheral scarring was 20 days (median, 11 days; range, 2-66 days). Sclerocorneal tunnel infection must be microbiologically evaluated. Intensive medical management, wound revision and repair may lead to a favorable outcome.

Monitoring pilot projects on bored tunnelling : The Second Heinenoord Tunnel and the Botlek Rail Tunnel

NARCIS (Netherlands)

Bakker, K.J.; De Boer, F.; Admiraal, J.B.M.; Van Jaarsveld, E.P.

1999-01-01

Two pilot projects for bored tunnelling in soft soil have been undertaken in the Netherlands. The monitoring was commissioned under the authority of the Centre for Underground Construction (COB). A description of the research related to the Second Heinenoord Tunnel and the Botlek Rail Tunnel will be

Concurrent myotomy and tunneling after establishment of a half tunnel instead of myotomy after establishment of a full tunnel: a more efficient method of peroral endoscopic myotomy.

Science.gov (United States)

Philips, George M; Dacha, Sunil; Keilin, Steve A; Willingham, Field F; Cai, Qiang

2016-04-01

Peroral endoscopic myotomy (POEM) is a time-consuming and challenging procedure. Traditionally, the myotomy is done after the submucosal tunnel has been completed. Starting the myotomy earlier, after submucosal tunneling is half completed (concurrent myotomy and tunneling), may be more efficient. This study aims to assess if the method of concurrent myotomy and tunneling may decrease the procedural time and be efficacious. This is a retrospective case series of patients who underwent modified POEM (concurrent myotomy and tunneling) or traditional POEM at a tertiary care medical center. Modified POEM or traditional POEM was performed at the discretion of the endoscopist in patients presenting with achalasia. The total procedural duration, myotomy duration, myotomy length, and time per unit length of myotomy were recorded for both modified and traditional POEM. Modified POEM was performed in 6 patients whose mean age (± standard deviation [SD]) was 58 ± 13.3 years. Of these, 5 patients had type II achalasia and 1 patient had esophageal dysmotility. The mean Eckardt score (± SD) before the procedure was 8.8 ± 1.3. The modified technique was performed in 47 ± 8 minutes, with 6 ± 1 minutes required per centimeter of myotomy and 3 ± 1 minutes required per centimeter of submucosal space. The Eckardt score was 3 ± 1.1 at 1 month and 3 ± 2.5 at 3 months. The procedure time for modified POEM was significantly shorter than that for traditional POEM. Modified POEM with short submucosal tunneling may be more efficient than traditional POEM with long submucosal tunneling, and outcomes may be equivalent over short-term follow-up. Long-term data and randomized controlled studies are needed to compare the clinical efficacy of modified POEM with that of the traditional method.

Restoring proximal caries lesions conservatively with tunnel restorations

Directory of Open Access Journals (Sweden)

Chu CH

2013-07-01

Full Text Available Chun-Hung Chu1, May L Mei,1 Chloe Cheung,1 Romesh P Nalliah2 1Faculty of Dentistry, The University of Hong Kong, Hong Kong, People's Republic of China; 2Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA, USA Abstract: The tunnel restoration has been suggested as a conservative alternative to the conventional box preparation for treating proximal caries. The main advantage of tunnel restoration over the conventional box or slot preparation includes being more conservative and increasing tooth integrity and strength by preserving the marginal ridge. However, tunnel restoration is technique-sensitive and can be particularly challenging for inexperienced restorative dentists. Recent advances in technology, such as the contemporary design of dental handpieces with advanced light-emitting diode (LED and handheld comfort, offer operative dentists better vision, illumination, and maneuverability. The use of magnifying loupes also enhances the visibility of the preparation. The advent of digital radiographic imaging has improved dental imaging and reduced radiation. The new generation of restorative materials has improved mechanical properties. Tunnel restoration can be an option to restore proximal caries if the dentist performs proper case selection and pays attention to the details of the restorative procedures. This paper describes the clinical technique of tunnel restoration and reviews the studies of tunnel restorations. Keywords: operative, practice, tunnel preparation, composite, amalgam, glass ionomer

Relationship between Widening and Position of the Tunnels and Clinical Results of Anterior Cruciate Ligament Reconstruction to Knee Osteoarthritis: 30 Patients at a Minimum Follow-Up of 10 Years.

Science.gov (United States)

Ayala-Mejias, Juan Diego; Garcia-Gonzalez, Benjamin; Alcocer-Perez-España, Luis; Villafañe, Jorge Hugo; Berjano, Pedro

2017-07-01

To evaluate the relationship between tunnel position and widening and long-term clinical results in anterior cruciate ligament (ACL) reconstruction, a retrospective cohort of 30 patients undergoing ACL reconstruction with double semitendinous plus double gracilis (SAC technique) with longer than 10-year follow-up was selected. CT scans in the first 3 months and at final follow-up was evaluated. Position, angle, and widening of tunnels including Nebelung criteria were recorded in all CT scans. Physical, KT-1000, and clinical evaluation were performed at final follow-up. Outcomes and knee arthritis severity were evaluated at final follow-up. Mean follow-up was 11.2 ± 1.2. At final follow-up, 85 and 57% of tibial and femoral tunnels, respectively, developed some degree of enlargement. Frontal tibial angle (mean) was 72°, sagittal tibial angle 63°, frontal femoral angle 47°, sagittal femoral angle 20°, and tunnels divergence angle 36°. Preoperatively, KT-1000 30L and Lachman test scores were 5.52 and 5.79 respectively. In the last follow-up, 30L and manual Lachman test scores were 0.97 and 1.13, respectively ( p  verticalization. Tibial tunnel dilation was associated with long-term degenerative changes but not with final knee instability. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

Alternative diagnostic technique for carpal tunnel syndrome

International Nuclear Information System (INIS)

Hayakawa, Katsuhiko; Nakane, Takashi; Kobayashi, Shigeru; Shibata, Kunio

2002-01-01

Compressive and entrapment neuropathies are common clinical syndromes characterized by neurologic deficits due to mechanical or dynamic compression of peripheral nerves. However, the definitive diagnosis based on clinical symptoms alone is difficult in many cases, and the electrophysiological diagnostic method is solely used as a supplementary diagnostic method at present. As a new diagnostic method for entrapment neuropathy, the present study investigated the usefulness of gadolinium-enhanced MRI in carpal tunnel syndrome. On enhanced MRI of idiopathic carpal tunnel syndrome, contrast-enhancement in the median nerve was found in 30 of 34 hands (88.2%). Enhanced MRI allows to visualize intraneural edema in the nerve easily on the naked eye. Therefore, this technique supplied useful information for making definitive diagnosis and is promising as a non-invasive diagnostic method for entrapment neuropathy. (author)

Alternative diagnostic technique for carpal tunnel syndrome

Energy Technology Data Exchange (ETDEWEB)

Hayakawa, Katsuhiko; Nakane, Takashi [Aiko Orthopaedic Hospital, Nagoya (Japan); Kobayashi, Shigeru; Shibata, Kunio [Fujita Health Univ., Toyoake, Aichi (Japan). School of Medicine

2002-10-01

Compressive and entrapment neuropathies are common clinical syndromes characterized by neurologic deficits due to mechanical or dynamic compression of peripheral nerves. However, the definitive diagnosis based on clinical symptoms alone is difficult in many cases, and the electrophysiological diagnostic method is solely used as a supplementary diagnostic method at present. As a new diagnostic method for entrapment neuropathy, the present study investigated the usefulness of gadolinium-enhanced MRI in carpal tunnel syndrome. On enhanced MRI of idiopathic carpal tunnel syndrome, contrast-enhancement in the median nerve was found in 30 of 34 hands (88.2%). Enhanced MRI allows to visualize intraneural edema in the nerve easily on the naked eye. Therefore, this technique supplied useful information for making definitive diagnosis and is promising as a non-invasive diagnostic method for entrapment neuropathy. (author)

Pharmacological and clinical evidence of nevirapine immediate- and extended-release formulations

Directory of Open Access Journals (Sweden)

Ena J

2012-11-01

extended release, efficacy, safety, resistance, clinical practice

Tunnel magnetoresistance in asymmetric double-barrier magnetic tunnel junctions

International Nuclear Information System (INIS)

Useinov, N.Kh.; Petukhov, D.A.; Tagirov, L.R.

2015-01-01

The spin-polarized tunnel conductance and tunnel magnetoresistance (TMR) through a planar asymmetric double-barrier magnetic tunnel junction (DBMTJ) have been calculated using quasi-classical model. In DBMTJ nanostructure the magnetization of middle ferromagnetic metal layer can be aligned parallel or antiparallel with respect to the fixed magnetizations of the top and bottom ferromagnetic electrodes. The transmission coefficients of an electron to pass through the barriers have been calculated in terms of quantum mechanics. The dependencies of tunnel conductance and TMR on the applied voltage have been calculated in case of non-resonant transmission. Estimated in the framework of our model, the difference between the spin-channels conductances at low voltages was found relatively large. This gives rise to very high magnitude of TMR. - Highlights: • The spin-polarized conductance through the junction is calculated. • Dependencies of the tunnel conductance vs applied bias are shown. • Bias voltage dependence of tunnel magnetoresistance for the structure is shown

Study on Hot Gases Flow in Case of Fire in a Road Tunnel

Directory of Open Access Journals (Sweden)

Aleksander Król

2018-03-01

Full Text Available This paper presents the results of hot smoke tests, which were conducted in a real road tunnel. The tunnel is located within the expressway S69 in southern Poland between cities Żywiec and Zwardoń. Its common name is Laliki tunnel. It is a bidirectional non-urban tunnel. The length of the tunnel is 678 m and it is inclined by 4%. It is equipped with the longitudinal ventilation system. Two hot smoke tests have been carried out according to Australian Standard AS 4391-1999. Hot smoke tests corresponded to a Heat Release Rate (HRR equal to respectively 750 kW and 1500 kW. The fire source was located in the middle of the road lane imitating an initial phase of a car fire (respectively 150 m and 265 m from S portal. The temperature distribution was recorded during both tests using a set of fourteen thermocouples that were mounted at two stand poles located at the main axis of the tunnel on windward. The stand poles were placed at distances of 5 m and 10 m. The recorded data were applied to validate a numerical model, which was built and solved using Ansys Fluent. The calculated temperature distribution matched the measured values.

Comparison of the Effects between Sweet Bee Venom Pharmacopuncture and Scolopendrid Pharmacopuncture on Carpal Tunnel Syndrome (Randomized, Controlled Clinical Trial

Directory of Open Access Journals (Sweden)

Ji-young Ku

2010-12-01

Full Text Available Objectives : The purpose of this study is to compare the effects of Sweet Bee Venom Pharmacopuncture and Scolopendrid Pharmacopuncture on Carpal Tunnel Syndrome. Methods : From February to September 2010, the number of patients with Carpal Tunnel Syndrome who volunteered for this clinical study was 16 and 7 out of 16 patients complained both hands. Total 23 cases of hands were randomly divided by 2 groups. We injected Sweet Bee Venom Pharmacopuncture on PC7(Daereung twice a week for 4weeks for experimental group(n=11, and Scolopendrid Pharmacopuncture with the same methods for control group(n=12. One case was dropped out due to itchiness of allergic response in the experimental group. Improvement of the symptoms was evaluated by Visual Analogue Scale, Pain Rating Scale, Tinel’s sign, Phalen’s sign and Nerve Conduction Velocity. Nerve Conduction Velocity was checked at baseline and the end of the trial and others were checked at baseline, after 2 and 4 weeks. Results : Both groups showed significant improvement in Visual Analogue Scale, Pain Rating Scale, but no significant difference between two groups. Only the control group showed significant reduction of the‘ poitive response’in the Tinel’s sign and Phalen’s sign. However, no groups improved in Nerve Conduction Velocity. Conclusions : These results showed that Sweet Bee Venom Pharmacopuncture and Scolopendrid Pharmacopuncture could decrease the symptoms of Carpal Tunnel Syndrome. Further studies will be required to examine more cases for the long period and use more various concentration and amount pharmacopuncture for the effect on Carpal Tunnel Syndrome.

Case Study of Oriental Medicine Treatment with acupotomy Therpy of the Tarsal tunnel Syndrome

Directory of Open Access Journals (Sweden)

Lim Na-ra

2009-03-01

Full Text Available Purpose : In order to estimate clinical effects of Oriental Medicine Treatment with acupotomy therapy of Tarsal tunnel Syndrome Methods : From 5th November, 2008 to 8th November, 2008, 1 male patient diagnosed as Tarsal tunnel syndrome(clinical diagnosed was treated with general oriental medicine therapy (acupuncture, moxibustion, cupping, physical therapy, herbal medication and acupotomy. Results : The patient's Rt foot paresthesia, pain were remarkably improved. Conclusions : This study demonstrates that oriental medical treatment with acuputomy therapy has notable effect in improving symptoms of tarsal tunnel syndrome. as though we had not wide experience in this treatment, more research is needed.

[Occupational carpal tunnel syndrome: 27 cases].

Science.gov (United States)

Slimane, Neila Ben; Elleuch, Mohamed; Gharbi, Ezzedine; Babay, Habib; Hamdoun, Moncef

2010-09-01

Carpal tunnel syndrome is the most frequent of tunnel syndromes in the field of the professional sphere. It is related to repetitive movements of flexion-extension of the wrist and fingers or to a support on the heel of the hands. To determine the posts in a risk and to specify the modalities of guaranteed reimbursement of professional carpal tunnel syndrome. A retrospective and descriptive study of 27 medical files of employees indemnified for professional carpal tunnel syndrome registered in the medical control services of the social security office in charge of medical insurance of Tunis and Sousse during a period of 10 years (1995-2004). There were 24 women and 3 men with the average age of 40 years all occupying posts in a risk. Their average time of service is 15 years. Tow-thirds of them work in the clothing and textile industry. The attack is bilateral in 13 cases. Nightly acroparaesthesia rules the clinical rate (44.44% of cases). Motor disorders are noted in the quarter of cases. The electromyogram had confirmed diagnosis in all of cases. The previous state study put in evidence the antecedent of carpal tunnel syndrome in 5 cases and diabetes in one case. Twenty-one patients had profit of permanent partial incapacity with a rate varying from 3 to 25%. Five had got a transfer of working place and one stayed in the same post with a half-time work. The professional origin of carpal tunnel syndrome must be called up in front of an activity in a risk. The reparation is done according to picture 82 of occupational diseases.

An Experimental Study on Burning Characteristics of n-Heptane/Ethanol Mixture Pool Fires in a Reduced Scaled Tunnel

Science.gov (United States)

Yozgatligil, Ahmet; Shafee, Sina

2016-11-01

Fire accidents in recent decades have drawn attention to safety issues associated with the design, construction and maintenance of tunnels. A reduced scale tunnel model constructed based on Froude scaling technique is used in the current work. Mixtures of n-heptane and ethanol are burned with ethanol volumetric fraction up to 30 percent and the longitudinal ventilation velocity varying from 0.5 to 2.5 m/s. The burning rates of the pool fires are measured using a precision load cell. The heat release rates of the fires are calculated according to oxygen calorimetry method and the temperature distributions inside the tunnel are also measured. Results of the experiments show that the ventilation velocity variation has a significant effect on the pool fire burning rate, smoke temperature and the critical ventilation velocity. With increased oxygen depletion in case of increased ethanol content of blended pool fires, the quasi-steady heat release rate values tend to increase as well as the ceiling temperatures while the combustion duration decreases.

Magnetic tunnel junctions with monolayer hexagonal boron nitride tunnel barriers

Energy Technology Data Exchange (ETDEWEB)

Piquemal-Banci, M.; Galceran, R.; Bouzehouane, K.; Anane, A.; Petroff, F.; Fert, A.; Dlubak, B.; Seneor, P. [Unité Mixte de Physique, CNRS, Thales, Univ. Paris-Sud, Université Paris-Saclay, Palaiseau 91767 (France); Caneva, S.; Martin, M.-B.; Weatherup, R. S.; Kidambi, P. R.; Robertson, J.; Hofmann, S. [Department of Engineering, University of Cambridge, Cambridge CB21PZ (United Kingdom); Xavier, S. [Thales Research and Technology, 1 avenue Augustin Fresnel, Palaiseau 91767 (France)

2016-03-07

We report on the integration of atomically thin 2D insulating hexagonal boron nitride (h-BN) tunnel barriers into Co/h-BN/Fe magnetic tunnel junctions (MTJs). The h-BN monolayer is directly grown by chemical vapor deposition on Fe. The Conductive Tip Atomic Force Microscopy (CT-AFM) measurements reveal the homogeneity of the tunnel behavior of our h-BN layers. As expected for tunneling, the resistance depends exponentially on the number of h-BN layers. The h-BN monolayer properties are also characterized through integration into complete MTJ devices. A Tunnel Magnetoresistance of up to 6% is observed for a MTJ based on a single atomically thin h-BN layer.

Interaction between groundwater and TBM (Tunnel Boring Machine) excavated tunnels

OpenAIRE

Font Capó, Jordi

2012-01-01

A number of problems, e.g. sudden inflows are encountered during tunneling under the piezometric level, especially when the excavation crosses high transmissivity areas. These inflows may drag materials when the tunnel crosses low competent layers, resulting in subsidence, chimney formation and collapses. Moreover, inflows can lead to a decrease in head level because of aquifer drainage. Tunnels can be drilled by a tunnel boring machine (TBM) to minimize inflows and groundwater impacts, restr...

Assessment of Relevant Exposure Pathways in Scenario of Reuse of Very Low Level Radioactive Steel in Tunnel Constructions

International Nuclear Information System (INIS)

Hrncir, T.; Necas, V.

2012-01-01

Decommissioning process and related management of generated radioactive materials during this process became important topics during last several years because of continuously increasing number of nuclear power plant approaching the end of their lifetime. The very low level radioactive waste category includes considerable amount of materials arising from decommissioning. In line with international incentives of optimization of the waste management process, alternative concepts of recycling and reuse of materials are considered. One of these concepts of such optimization is the conditional release of materials with their subsequent recycling and reuse in industrial or nuclear sector. This paper is devoted to an option of recycling and reuse of conditionally released steel in industrial sector, specifically in motorway tunnel constructions. It is assumed that very low level radioactive steel would be released and reused in form of steel reinforcing components, such as steel nets and bars, assembled in primary and secondary lining of motorway tunnel. Assessment of exposure pathways relevant for construction, operation and post-operation period was performed. The computational tool VISIPLAN 3D ALARA was used for calculation of external individual effective dose for personnel constructing the tunnel and for members of the public driving through already built motorway tunnel. The simulation software GOLDSIM was used for the assessment of internal exposure pathways. GOLDSIM environment enables modelling of degradation processes and transport of radionuclides through unsaturated and saturated zone of subsoil. There are international recommendations available for the concept of release of radioactive materials into the environment derived from the principles that the individual effective dose received by critical individual must not exceed some tens of microSv/yr. Dose limits 10 microSv/yr or 50 microSv/yr considering specific conditions are stated in Slovak legislation

Light-stimulated cargo release from a core–shell structured nanocomposite for site-specific delivery

International Nuclear Information System (INIS)

Cai, Yun; Ling, Li; Li, Xiaofang; Chen, Meng; Su, Likai

2015-01-01

This paper reported a core–shell structured site-specific delivery system with a light switch triggered by low energy light (λ=510 nm). Its core was composed of supermagnetic Fe 3 O 4 nanoparticles for magnetic guiding and targeting. Its outer shell consisted of mesoporous silica molecular sieve MCM-41 which offered highly ordered hexagonal tunnels for cargo capacity. A light switch N1-(4aH-cyclopenta[1,2-b:5,4-b′]dipyridin-5(5aH)-ylidene)benzene-1, 4-diamine (CBD) was covalently grafted into these hexagonal tunnels, serving as light stimuli acceptor with loading content of 1.1 μM/g. This composite was fully characterized and confirmed by SEM, TEM, XRD patterns, N 2 adsorption/desorption, thermogravimetric analysis, IR, UV–vis absorption and emission spectra. Experimental data suggested that this composite had a core as wide as 150 nm and could be magnetically guided to specific sites. Its hexagonal tunnels were as long as 180 nm. Upon light stimuli of “on” and “off” states, controllable release was observed with short release time of ~900 s (90% capacity). - Graphical abstract: A core–shell structured site-specific delivery system with a light switch triggered by yellow light was constructed. Controllable release was observed with short release time of ~900 s (90% capacity). - Highlights: • A core–shell structured site-specific delivery system was constructed. • It consisted of Fe 3 O 4 core and MCM-41 shell grafted with light switch. • This delivery system was triggered by low energy light. • Controllable release was observed with short release time of ~900 s

Light-stimulated cargo release from a core–shell structured nanocomposite for site-specific delivery

Energy Technology Data Exchange (ETDEWEB)

Cai, Yun; Ling, Li; Li, Xiaofang [Department of Neurology, Affiliated Hospital of Hebei University, Baoding 071000 (China); Chen, Meng [Department of Rheumatology, Affiliated Hospital of Hebei University, Baoding 071000 (China); Su, Likai, E-mail: zhangdong19992003@163.com [Department of Neurology, Affiliated Hospital of Hebei University, Baoding 071000 (China)

2015-03-15

This paper reported a core–shell structured site-specific delivery system with a light switch triggered by low energy light (λ=510 nm). Its core was composed of supermagnetic Fe{sub 3}O{sub 4} nanoparticles for magnetic guiding and targeting. Its outer shell consisted of mesoporous silica molecular sieve MCM-41 which offered highly ordered hexagonal tunnels for cargo capacity. A light switch N1-(4aH-cyclopenta[1,2-b:5,4-b′]dipyridin-5(5aH)-ylidene)benzene-1, 4-diamine (CBD) was covalently grafted into these hexagonal tunnels, serving as light stimuli acceptor with loading content of 1.1 μM/g. This composite was fully characterized and confirmed by SEM, TEM, XRD patterns, N{sub 2} adsorption/desorption, thermogravimetric analysis, IR, UV–vis absorption and emission spectra. Experimental data suggested that this composite had a core as wide as 150 nm and could be magnetically guided to specific sites. Its hexagonal tunnels were as long as 180 nm. Upon light stimuli of “on” and “off” states, controllable release was observed with short release time of ~900 s (90% capacity). - Graphical abstract: A core–shell structured site-specific delivery system with a light switch triggered by yellow light was constructed. Controllable release was observed with short release time of ~900 s (90% capacity). - Highlights: • A core–shell structured site-specific delivery system was constructed. • It consisted of Fe{sub 3}O{sub 4} core and MCM-41 shell grafted with light switch. • This delivery system was triggered by low energy light. • Controllable release was observed with short release time of ~900 s.

Pathways and mechanisms for product release in the engineered haloalkane dehalogenases explored using classical and random acceleration molecular dynamics simulations.

Science.gov (United States)

Klvana, Martin; Pavlova, Martina; Koudelakova, Tana; Chaloupkova, Radka; Dvorak, Pavel; Prokop, Zbynek; Stsiapanava, Alena; Kuty, Michal; Kuta-Smatanova, Ivana; Dohnalek, Jan; Kulhanek, Petr; Wade, Rebecca C; Damborsky, Jiri

2009-10-09

Eight mutants of the DhaA haloalkane dehalogenase carrying mutations at the residues lining two tunnels, previously observed by protein X-ray crystallography, were constructed and biochemically characterized. The mutants showed distinct catalytic efficiencies with the halogenated substrate 1,2,3-trichloropropane. Release pathways for the two dehalogenation products, 2,3-dichloropropane-1-ol and the chloride ion, and exchange pathways for water molecules, were studied using classical and random acceleration molecular dynamics simulations. Five different pathways, denoted p1, p2a, p2b, p2c, and p3, were identified. The individual pathways showed differing selectivity for the products: the chloride ion releases solely through p1, whereas the alcohol releases through all five pathways. Water molecules play a crucial role for release of both products by breakage of their hydrogen-bonding interactions with the active-site residues and shielding the charged chloride ion during its passage through a hydrophobic tunnel. Exchange of the chloride ions, the alcohol product, and the waters between the buried active site and the bulk solvent can be realized by three different mechanisms: (i) passage through a permanent tunnel, (ii) passage through a transient tunnel, and (iii) migration through a protein matrix. We demonstrate that the accessibility of the pathways and the mechanisms of ligand exchange were modified by mutations. Insertion of bulky aromatic residues in the tunnel corresponding to pathway p1 leads to reduced accessibility to the ligands and a change in mechanism of opening from permanent to transient. We propose that engineering the accessibility of tunnels and the mechanisms of ligand exchange is a powerful strategy for modification of the functional properties of enzymes with buried active sites.

High resolution imaging of tunnels by magnetic resonance neurography

Energy Technology Data Exchange (ETDEWEB)

Subhawong, Ty K.; Thawait, Shrey K.; Machado, Antonio J.; Carrino, John A.; Chhabra, Avneesh [Johns Hopkins Hospital, The Russell H. Morgan Department of Radiology and Radiological Science, Baltimore, MD (United States); Wang, Kenneth C. [Baltimore VA Medical Center, Department of Radiology, Baltimore, MD (United States); Williams, Eric H. [Dellon Institute for Peripheral Nerve Surgery, Towson, MD (United States); Hashemi, Shahreyar Shar [Johns Hopkins Hospital, Division of Plastic and Reconstructive Surgery, Baltimore, MD (United States)

2012-01-15

Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment. (orig.)

High resolution imaging of tunnels by magnetic resonance neurography

International Nuclear Information System (INIS)

Subhawong, Ty K.; Thawait, Shrey K.; Machado, Antonio J.; Carrino, John A.; Chhabra, Avneesh; Wang, Kenneth C.; Williams, Eric H.; Hashemi, Shahreyar Shar

2012-01-01

Peripheral nerves often traverse confined fibro-osseous and fibro-muscular tunnels in the extremities, where they are particularly vulnerable to entrapment and compressive neuropathy. This gives rise to various tunnel syndromes, characterized by distinct patterns of muscular weakness and sensory deficits. This article focuses on several upper and lower extremity tunnels, in which direct visualization of the normal and abnormal nerve in question is possible with high resolution 3T MR neurography (MRN). MRN can also serve as a useful adjunct to clinical and electrophysiologic exams by discriminating adhesive lesions (perineural scar) from compressive lesions (such as tumor, ganglion, hypertrophic callous, or anomalous muscles) responsible for symptoms, thereby guiding appropriate treatment. (orig.)

Frequency driven inversion of tunnel magnetoimpedance and observation of positive tunnel magnetocapacitance in magnetic tunnel junctions

International Nuclear Information System (INIS)

Parui, Subir; Ribeiro, Mário; Atxabal, Ainhoa; Llopis, Roger; Bedoya-Pinto, Amilcar; Sun, Xiangnan; Casanova, Fèlix; Hueso, Luis E.

2016-01-01

The relevance for modern computation of non-volatile high-frequency memories makes ac-transport measurements of magnetic tunnel junctions (MTJs) crucial for exploring this regime. Here, we demonstrate a frequency-mediated effect in which the tunnel magnetoimpedance reverses its sign in a classical Co/Al 2 O 3 /NiFe MTJ, whereas we only observe a gradual decrease in the tunnel magnetophase. Such effects are explained by the capacitive coupling of a parallel resistor and capacitor in the equivalent circuit model of the MTJ. Furthermore, we report a positive tunnel magnetocapacitance effect, suggesting the presence of a spin-capacitance at the two ferromagnet/tunnel-barrier interfaces. Our results are important for understanding spin transport phenomena at the high frequency regime in which the spin-polarized charge accumulation due to spin-dependent penetration depth at the two interfaces plays a crucial role.

Frequency driven inversion of tunnel magnetoimpedance and observation of positive tunnel magnetocapacitance in magnetic tunnel junctions

Energy Technology Data Exchange (ETDEWEB)

Parui, Subir, E-mail: s.parui@nanogune.eu, E-mail: l.hueso@nanogune.eu; Ribeiro, Mário; Atxabal, Ainhoa; Llopis, Roger [CIC nanoGUNE, 20018 Donostia-San Sebastian (Spain); Bedoya-Pinto, Amilcar [CIC nanoGUNE, 20018 Donostia-San Sebastian (Spain); Max Planck Institute of Microstructure Physics, D-06120 Halle (Germany); Sun, Xiangnan [CIC nanoGUNE, 20018 Donostia-San Sebastian (Spain); National Center for Nanoscience and Technology, 100190 Beijing (China); Casanova, Fèlix; Hueso, Luis E., E-mail: s.parui@nanogune.eu, E-mail: l.hueso@nanogune.eu [CIC nanoGUNE, 20018 Donostia-San Sebastian (Spain); IKERBASQUE, Basque Foundation for Science, 48011 Bilbao (Spain)

2016-08-01

The relevance for modern computation of non-volatile high-frequency memories makes ac-transport measurements of magnetic tunnel junctions (MTJs) crucial for exploring this regime. Here, we demonstrate a frequency-mediated effect in which the tunnel magnetoimpedance reverses its sign in a classical Co/Al{sub 2}O{sub 3}/NiFe MTJ, whereas we only observe a gradual decrease in the tunnel magnetophase. Such effects are explained by the capacitive coupling of a parallel resistor and capacitor in the equivalent circuit model of the MTJ. Furthermore, we report a positive tunnel magnetocapacitance effect, suggesting the presence of a spin-capacitance at the two ferromagnet/tunnel-barrier interfaces. Our results are important for understanding spin transport phenomena at the high frequency regime in which the spin-polarized charge accumulation due to spin-dependent penetration depth at the two interfaces plays a crucial role.

3D Centrifuge Modeling of the Effect of Twin Tunneling to an Existing Pile Group

Directory of Open Access Journals (Sweden)

M. A. Soomr

2017-10-01

Full Text Available In densely built urban areas, it is inevitable that tunnels will be constructed near existing pile groups. The bearing capacity of a pile group depends on shear stress along the soil-pile interface and normal stress underneath the pile toe while the two would be adversely affected by the unloading process of tunneling. Although extensive studies have been conducted to investigate the effects of tunnel construction on existing single piles, the influence of twin tunnel advancement on an existing pile group is merely reported in the literature. In this study, a series of three-dimensional centrifuge tests were carried out to investigate the response of an existing pile group under working load subjected to twin tunneling at various locations in dry Toyoura sand. In each twin tunneling test, the first tunnel is constructed near the mid-depth of the pile shaft, while the second tunnel is subsequently constructed either next to, below or right underneath the pile toe (Tests G_ST, G_SB and G_SU, respectively. Among the three tests, the 2nd tunnel excavated near the pile toe (Test G_ST results in the smallest settlement but the largest transverse tilting (0.2% of pile group. Significant bending moment was induced at the pile head (1.4 times of its bending moment capacity due to the 2nd tunnel T. On the contrary, tunneling right underneath the toe of pile (i.e., Test G_SU results in the smallest tilting but largest settlement of the pile group (4.6% of pile diameter and incremental mobilisation of shaft resistance (13%. Due to stress release by the twin tunneling, the axial force taken by the front piles close to tunnels was reduced and partially transferred to the rear piles. This load transfer can increase the axial force in rear piles by 24%.

Carpal Tunnel Syndrome

Science.gov (United States)

... a passing cramp? It could be carpal tunnel syndrome. The carpal tunnel is a narrow passageway of ... three times more likely to have carpal tunnel syndrome than men. Early diagnosis and treatment are important ...

Numerical Simulation of Rock Mass Damage Evolution During Deep-Buried Tunnel Excavation by Drill and Blast

Science.gov (United States)

Yang, Jianhua; Lu, Wenbo; Hu, Yingguo; Chen, Ming; Yan, Peng

2015-09-01

Presence of an excavation damage zone (EDZ) around a tunnel perimeter is of significant concern with regard to safety, stability, costs and overall performance of the tunnel. For deep-buried tunnel excavation by drill and blast, it is generally accepted that a combination of effects of stress redistribution and blasting is mainly responsible for development of the EDZ. However, few open literatures can be found to use numerical methods to investigate the behavior of rock damage induced by the combined effects, and it is still far from full understanding how, when and to what degree the blasting affects the behavior of the EDZ during excavation. By implementing a statistical damage evolution law based on stress criterion into the commercial software LS-DYNA through its user-subroutines, this paper presents a 3D numerical simulation of the rock damage evolution of a deep-buried tunnel excavation, with a special emphasis on the combined effects of the stress redistribution of surrounding rock masses and the blasting-induced damage. Influence of repeated blast loadings on the damage extension for practical millisecond delay blasting is investigated in the present analysis. Accompanying explosive detonation and secession of rock fragments from their initial locations, in situ stress in the immediate vicinity of the excavation face is suddenly released. The transient characteristics of the in situ stress release and induced dynamic responses in the surrounding rock masses are also highlighted. From the simulation results, some instructive conclusions are drawn with respect to the rock damage mechanism and evolution during deep-buried tunnel excavation by drill and blast.

Theory of superconducting tunneling without the tunneling Hamiltonian

International Nuclear Information System (INIS)

Arnold, G.B.

1987-01-01

When a tunneling barrier is nearly transparent, the standard tunneling (or transfer) Hamiltonian approximation fails. The author describes the theory which is necessary for calculating the tunneling current in these cases, and illustrate it by comparing theory and experiment on superconductor/insulator/superconductor (SIS) junctions have ultra-thin tunnel barriers. This theory accurately explains the subgap structure which appears in the dynamical resistance of such SIS junctions, including many observed details which no previous theory has reproduced. The expression for the current through an SIS junction with an ultrathin barrier is given by I(t) = Re{Sigma/sub n/ J/sub n/ (omega/sub o/)e/sup in omega/o/sup t/} where omega/sub o/ = 2eV/h is the Josephson frequency, V is the bias voltage, and the J/sub n/ are voltage dependent coefficients, one for each positive or negative integer, n, and n=0. The relative sign of the terms involving cos(n omega/sub o/t) and sin(n omega/sub o/t) agrees with experiment, in contrast to previous theories of Josephson tunneling

Methodology of using CFD-based risk assessment in road tunnels

Directory of Open Access Journals (Sweden)

Vidmar Peter

2007-01-01

Full Text Available The definition of the deterministic approach in the safety analyses comes from the need to understand the conditions that come out during the fire accident in a road tunnel. The key factor of the tunnel operations during the fire is the ventilation, which during the initial fazes of the fire, impact strongly on the evacuation of people and latter on the access of the intervention units in the tunnel. The paper presents the use of the computational fluid dynamics model in the tunnel safety assessment process. The model is validated by comparing data with experimental and quantifying the differences. The set-up of the initial and boundary conditions and the requirement for grid density found during the validation tests is used to prepare three kind of fire scenarios 20 MW, 50 MW, and 100 MW, with different ventilation conditions; natural, semi transverse, full transverse, and longitudinal ventilation. The observed variables, soot density and temperature, are presented in minutes time steps trough the entire tunnel length. Comparing the obtained data in a table, allows the analyses of the ventilation conditions for different heat releases from fires. The second step is to add additional criteria of human behaviour inside the tunnel (evacuation and human resistance to the elevated gas concentrations and temperature. What comes out is a fully deterministic risk matrix that is based on the calculated data where the risk is ranged on five levels, from the lowest to a very danger level. The deterministic risk matrix represents the alternative to a probabilistic safety assessment methodology, where the fire risk is represented in detail as well as the computational fluid dynamics model results are physically correct. .

Social media release increases dissemination of original articles in the clinical pain sciences.

Science.gov (United States)

Allen, Heidi G; Stanton, Tasha R; Di Pietro, Flavia; Moseley, G Lorimer

2013-01-01

A barrier to dissemination of research is that it depends on the end-user searching for or 'pulling' relevant knowledge from the literature base. Social media instead 'pushes' relevant knowledge straight to the end-user, via blogs and sites such as Facebook and Twitter. That social media is very effective at improving dissemination seems well accepted, but, remarkably, there is no evidence to support this claim. We aimed to quantify the impact of social media release on views and downloads of articles in the clinical pain sciences. Sixteen PLOS ONE articles were blogged and released via Facebook, Twitter, LinkedIn and ResearchBlogging.org on one of two randomly selected dates. The other date served as a control. The primary outcomes were the rate of HTML views and PDF downloads of the article, over a seven-day period. The critical result was an increase in both outcome variables in the week after the blog post and social media release. The mean ± SD rate of HTML views in the week after the social media release was 18±18 per day, whereas the rate during the other three weeks was no more than 6±3 per day. The mean ± SD rate of PDF downloads in the week after the social media release was 4±4 per day, whereas the rate during the other three weeks was less than 1±1 per day (psocial media reach, engagement or virality related to either outcome variable, nor to citation count one year later (p>0.3 for all). We conclude that social media release of a research article in the clinical pain sciences increases the number of people who view or download that article, but conventional social media metrics are unrelated to the effect.

Social media release increases dissemination of original articles in the clinical pain sciences.

Directory of Open Access Journals (Sweden)

Heidi G Allen

Full Text Available A barrier to dissemination of research is that it depends on the end-user searching for or 'pulling' relevant knowledge from the literature base. Social media instead 'pushes' relevant knowledge straight to the end-user, via blogs and sites such as Facebook and Twitter. That social media is very effective at improving dissemination seems well accepted, but, remarkably, there is no evidence to support this claim. We aimed to quantify the impact of social media release on views and downloads of articles in the clinical pain sciences. Sixteen PLOS ONE articles were blogged and released via Facebook, Twitter, LinkedIn and ResearchBlogging.org on one of two randomly selected dates. The other date served as a control. The primary outcomes were the rate of HTML views and PDF downloads of the article, over a seven-day period. The critical result was an increase in both outcome variables in the week after the blog post and social media release. The mean ± SD rate of HTML views in the week after the social media release was 18±18 per day, whereas the rate during the other three weeks was no more than 6±3 per day. The mean ± SD rate of PDF downloads in the week after the social media release was 4±4 per day, whereas the rate during the other three weeks was less than 1±1 per day (p0.3 for all. We conclude that social media release of a research article in the clinical pain sciences increases the number of people who view or download that article, but conventional social media metrics are unrelated to the effect.

Dupuytren’s disease digital radius IV right hand and carpal tunnel syndrome on ipsilateral hand

Directory of Open Access Journals (Sweden)

Teona Sebe Ioana

2015-11-01

Full Text Available Dupuytren’s contracture is a fibroproliferative disease whose etiology and pathophysiology are unclear and controversial. It is a connective tissue disorder, which takes part in the palmar’s fibromatosis category and has common characteristics with the healing process. Dupuytren’s disease is characterized by the flexion contracture of the hand due to palmar and digital aponevrosis. It generally affects the 4th digital radius, followed by the 5th one. Without surgery, it leads to functional impotence of those digital rays and/or hand. It is associated with other diseases and situational conditions like Peyronie’s disease, the Lederhose disease (plantar fibromatosis, Garrod’s digital knuckle-pads, diabetes, epilepsy, alcoholism, micro traumatisms, stenosing tenosynovitis and not the least with carpal tunnel syndrome. The carpal tunnel syndrome is a peripheral neuropathy with the incarceration of the median nerve at the ARC level, expressed clinically by sensory and motor disturbances in the distribution territory of the median nerve, which cause functional limitations of daily activities of the patient. After the failure of the nonsurgical treatment or the appearance of the motor deficit, is established the open or endoscopic surgical treatment with the release of the median nerve. Postoperative recovery in both diseases is crucial to the functionality of the affected upper limb and to the quality of the patient’s life. The patient, a 61 years old man, admitted to the clinic for the functional impotence of the right hand, for the permanent flexion contracture of the metacarpophalangeal joint (MCP and proximal interphalangeal joint (PIP of the 4th finger with extension deficit, for the damage of the thumb pulp clamp of the 4th finger, for nocturnal paresthesia of fingers I-III and pain that radiates into the fingertips. After clinical, paraclinical, imagistic and electrical investigations, surgery is practiced partial aponevrectomy

Hydrogen Tunneling Links Protein Dynamics to Enzyme Catalysis

Science.gov (United States)

Klinman, Judith P.; Kohen, Amnon

2014-01-01

The relationship between protein dynamics and function is a subject of considerable contemporary interest. Although protein motions are frequently observed during ligand binding and release steps, the contribution of protein motions to the catalysis of bond making/breaking processes is more difficult to probe and verify. Here, we show how the quantum mechanical hydrogen tunneling associated with enzymatic C–H bond cleavage provides a unique window into the necessity of protein dynamics for achieving optimal catalysis. Experimental findings support a hierarchy of thermodynamically equilibrated motions that control the H-donor and -acceptor distance and active-site electrostatics, creating an ensemble of conformations suitable for H-tunneling. A possible extension of this view to methyl transfer and other catalyzed reactions is also presented. The impact of understanding these dynamics on the conceptual framework for enzyme activity, inhibitor/drug design, and biomimetic catalyst design is likely to be substantial. PMID:23746260

Tunneling works. Tunnel koji

Energy Technology Data Exchange (ETDEWEB)

Higo, M [Hazam Gumi, Ltd., Tokyo (Japan)

1991-10-25

A mountain tunneling method for rock-beds used to be applied mainly to construction works in the mountains under few restrictions by environmental problems. However, construction works near residential sreas have been increasing. There are such enviromental problems due to tunneling works as vibration, noise, lowering of ground-water level, and influences on other structures. This report mainly describes the measurement examples of vibration and noise accompanied with blasting and the effects of the measures to lessen such influences. When the tunneling works for the railroad was carried out on the natural ground mainly composed of basalt, vibration of the test blasting was measured at three stations with piezoelectric accelerometers. Then, ordinary blasting, mutistage blasting, and ABM blasting methods were used properly besed on the above results, and only a few complaints were made. In the different works, normal noise and low-frequency sound were mesured at 22 stations around the pit mouth. As countermeasures for noise, sound-proof sheets, walls, and single and double doors were installed and foundto be effective. 1 ref., 6 figs., 1 tab.

Simulative technology for auxiliary fuel tank separation in a wind tunnel

Directory of Open Access Journals (Sweden)

Ma Xin

2016-06-01

Full Text Available In this paper, we propose a simulative experimental system in wind tunnel conditions for the separation of auxiliary fuel tanks from an aircraft. The experimental system consists of a simulative release mechanism, a scaled model and a pose measuring system. A new release mechanism was designed to ensure stability of the separation. Scaled models of the auxiliary fuel tank were designed and their moment of inertia was adjusted by installing counterweights inside the model. Pose parameters of the scaled model were measured and calculated by a binocular vision system. Additionally, in order to achieve high brightness and high signal-to-noise ratio of the images in the dark enclosed wind tunnel, a new high-speed image acquisition method based on miniature self-emitting units was presented. Accuracy of the pose measurement system and repeatability of the separation mechanism were verified in the laboratory. Results show that the position precision of the pose measurement system can reach 0.1 mm, the precision of the pitch and yaw angles is less than 0.1° and that of the roll angle can be up to 0.3°. Besides, repeatability errors of models’ velocity and angular velocity controlled by the release mechanism remain small, satisfying the measurement requirements. Finally, experiments for the separation of auxiliary fuel tanks were conducted in the laboratory.

Effectiveness of manual therapy versus surgery in pain processing due to carpal tunnel syndrome: A randomized clinical trial.

Science.gov (United States)

Fernández-de-Las-Peñas, C; Cleland, J; Palacios-Ceña, M; Fuensalida-Novo, S; Alonso-Blanco, C; Pareja, J A; Alburquerque-Sendín, F

2017-08-01

People with carpal tunnel syndrome (CTS) exhibit widespread pressure pain and thermal pain hypersensitivity as a manifestation of central sensitization. The aim of our study was to compare the effectiveness of manual therapy versus surgery for improving pain and nociceptive gain processing in people with CTS. The trial was conducted at a local regional Hospital in Madrid, Spain from August 2014 to February 2015. In this randomized parallel-group, blinded, clinical trial, 100 women with CTS were randomly allocated to either manual therapy (n = 50), who received three sessions (once/week) of manual therapies including desensitization manoeuvres of the central nervous system, or surgical intervention (n = 50) group. Outcomes including pressure pain thresholds (PPT), thermal pain thresholds (HPT or CPT), and pain intensity which were assessed at baseline, and 3, 6, 9 and 12 months after the intervention by an assessor unaware of group assignment. Analysis was by intention to treat with mixed ANCOVAs adjusted for baseline scores. At 12 months, 95 women completed the follow-up. Patients receiving manual therapy exhibited higher increases in PPT over the carpal tunnel at 3, 6 and 9 months (all, p < 0.01) and higher decrease of pain intensity at 3 month follow-up (p < 0.001) than those receiving surgery. No significant differences were observed between groups for the remaining outcomes. Manual therapy and surgery have similar effects on decreasing widespread pressure pain sensitivity and pain intensity in women with CTS. Neither manual therapy nor surgery resulted in changes in thermal pain sensitivity. The current study found that manual therapy and surgery exhibited similar effects on decreasing widespread pressure pain sensitivity and pain intensity in women with carpal tunnel syndrome at medium- and long-term follow-ups investigating changes in nociceptive gain processing after treatment in carpal tunnel syndrome. © 2017 European Pain Federation - EFIC®.

Tunneling junction as an open system. Normal tunneling

International Nuclear Information System (INIS)

Ono, Y.

1978-01-01

The method of the tunneling Hamiltonian is reformulated in the case of normal tunneling by introducing two independent particle baths. Due to the baths, it becomes possible to realize a final stationary state where the electron numbers of the two electrodes in the tunneling system are maintained constant and where there exists a stationary current. The effect of the bath-system couplings on the current-voltage characteristics of the junction is discussed in relation to the usual expression of the current as a function of voltage. (Auth.)

Tunneling time, exit time and exit momentum in strong field tunnel ionization

International Nuclear Information System (INIS)

Teeny, Nicolas

2016-01-01

Tunnel ionization belongs to the fundamental processes of atomic physics. It is still an open question when does the electron tunnel ionize and how long is the duration of tunneling. In this work we solve the time-dependent Schroedinger equation in one and two dimensions and use ab initio quantum calculations in order to answer these questions. Additionally, we determine the exit momentum of the tunnel ionized electron from first principles. We find out results that are different from the assumptions of the commonly employed two-step model, which assumes that the electron ionizes at the instant of electric field maximum with a zero momentum. After determining the quantum final momentum distribution of tunnel ionized electrons we show that the two-step model fails to predict the correct final momentum. Accordingly we suggest how to correct the two-step model. Furthermore, we determine the instant at which tunnel ionization starts, which turns out to be different from the instant usually assumed. From determining the instant at which it is most probable for the electron to enter the tunneling barrier and the instant at which it exits we determine the most probable time spent under the barrier. Moreover, we apply a quantum clock approach in order to determine the duration of tunnel ionization. From the quantum clock we determine an average tunneling time which is different in magnitude and origin with respect to the most probable tunneling time. By defining a probability distribution of tunneling times using virtual detectors we relate both methods and explain the apparent discrepancy. The results found have in general an effect on the interpretation of experiments that measure the spectra of tunnel ionized electrons, and specifically on the calibration of the so called attoclock experiments, because models with imprecise assumptions are usually employed in order to interpret experimental results.

Tunneling time, exit time and exit momentum in strong field tunnel ionization

Energy Technology Data Exchange (ETDEWEB)

Teeny, Nicolas

2016-10-18

Tunnel ionization belongs to the fundamental processes of atomic physics. It is still an open question when does the electron tunnel ionize and how long is the duration of tunneling. In this work we solve the time-dependent Schroedinger equation in one and two dimensions and use ab initio quantum calculations in order to answer these questions. Additionally, we determine the exit momentum of the tunnel ionized electron from first principles. We find out results that are different from the assumptions of the commonly employed two-step model, which assumes that the electron ionizes at the instant of electric field maximum with a zero momentum. After determining the quantum final momentum distribution of tunnel ionized electrons we show that the two-step model fails to predict the correct final momentum. Accordingly we suggest how to correct the two-step model. Furthermore, we determine the instant at which tunnel ionization starts, which turns out to be different from the instant usually assumed. From determining the instant at which it is most probable for the electron to enter the tunneling barrier and the instant at which it exits we determine the most probable time spent under the barrier. Moreover, we apply a quantum clock approach in order to determine the duration of tunnel ionization. From the quantum clock we determine an average tunneling time which is different in magnitude and origin with respect to the most probable tunneling time. By defining a probability distribution of tunneling times using virtual detectors we relate both methods and explain the apparent discrepancy. The results found have in general an effect on the interpretation of experiments that measure the spectra of tunnel ionized electrons, and specifically on the calibration of the so called attoclock experiments, because models with imprecise assumptions are usually employed in order to interpret experimental results.

Quantum theory of tunneling

CERN Document Server

Razavy, Mohsen

2014-01-01

In this revised and expanded edition, in addition to a comprehensible introduction to the theoretical foundations of quantum tunneling based on different methods of formulating and solving tunneling problems, different semiclassical approximations for multidimensional systems are presented. Particular attention is given to the tunneling of composite systems, with examples taken from molecular tunneling and also from nuclear reactions. The interesting and puzzling features of tunneling times are given extensive coverage, and the possibility of measurement of these times with quantum clocks are critically examined. In addition by considering the analogy between evanescent waves in waveguides and in quantum tunneling, the times related to electromagnetic wave propagation have been used to explain certain aspects of quantum tunneling times. These topics are treated in both non-relativistic as well as relativistic regimes. Finally, a large number of examples of tunneling in atomic, molecular, condensed matter and ...

Spin-dependent tunnelling in magnetic tunnel junctions

International Nuclear Information System (INIS)

Tsymbal, Evgeny Y; Mryasov, Oleg N; LeClair, Patrick R

2003-01-01

The phenomenon of electron tunnelling has been known since the advent of quantum mechanics, but continues to enrich our understanding of many fields of physics, as well as creating sub-fields on its own. Spin-dependent tunnelling (SDT) in magnetic tunnel junctions (MTJs) has recently aroused enormous interest and has developed in a vigorous field of research. The large tunnelling magnetoresistance (TMR) observed in MTJs garnered much attention due to possible applications in non-volatile random-access memories and next-generation magnetic field sensors. This led to a number of fundamental questions regarding the phenomenon of SDT. In this review article we present an overview of this field of research. We discuss various factors that control the spin polarization and magnetoresistance in MTJs. Starting from early experiments on SDT and their interpretation, we consider thereafter recent experiments and models which highlight the role of the electronic structure of the ferromagnets, the insulating layer, and the ferromagnet/insulator interfaces. We also discuss the role of disorder in the barrier and in the ferromagnetic electrodes and their influence on TMR. (topical review)

Analysis of factors affecting failure of glass cermet tunnel restorations in a multi-center study.

Science.gov (United States)

Pilebro, C E; van Dijken, J W

2001-06-01

The aim of this study was to analyze factors influencing the failures of tunnel restorations performed with a glass cermet cement (Ketac Silver). Caries activity, lesion size, tunnel cavity opening size, partial or total tunnel, composite lamination or operating time showed no significant correlation to failure rate. Twelve dentists in eight clinics clinically experienced and familiar with the tunnel technique placed 374 restorations. The occlusal sections of fifty percent of the restorations were laminated with hybrid resin composite. The results of the yearly clinical and radiographic evaluations over the course of 3 years were correlated to factors that could influence the failure rate using logistic regression analysis. At the 3-year recall a cumulative number of 305 restorations were available. The cumulative replacement rate was 20%. The main reasons for replacement were marginal ridge fracture (14%) and dentin caries (3%). Another 7% of the restorations which had not been replaced were classified as failures because of untreated dentin caries. The only significant variable observed was the individual failure rate of the participating dentists varying between 9 and 50% (p=0.013).

Flow and solute transport in backfilled tunnel and collapsed backfill - possible extension of Comp32

International Nuclear Information System (INIS)

Neretnieks, Ivars

2006-09-01

In the Swedish deep geological final repository for spent fuel the tunnels will be filled with a backfill with low permeability. However, some flow may take place in the backfill. Nuclides released from a leaking canister could diffuse up to the flowing water in the backfill and be transported downstream in the tunnel. At an intersection of the tunnel with a fracture zone the contaminated water might flow out into the zone.This report addresses the transport mechanisms and rate of transport from a leaking canister up through the buffer and backfill in the deposition hole, further into the backfill in the tunnel and the transport along the tunnel. Spreading by diffusion in the buffer and backfill as well as retardation of sorbing nuclides is accounted for.The transport mechanisms and rates of transport are described and some simple models with analytical solutions are used to quantify the processes. These simple solutions are used to gain insights into when different transport mechanisms are important. The simple solutions are used to simulate a base case example where a non-sorbing nuclide (iodide) and a sorbing nuclide (radium) move in the backfill by diffusion and by advective flow. The simple sample calculations show that it would take thousands of years for iodide to move 20 m along the tunnel and that a release pulse would spread out considerably over time. The sorbing nuclide 226 Ra with a half life of 1,600 years would be strongly retarded by sorption and would decay to insignificance during its migration along the tunnel. The consequences of a collapse of backfill leaving a channel above the backfill is also studied by a simple analytical model that accounts for water flowing in the collapsed part of the backfill at the ceiling of the tunnel. A nuclide that diffuses up to the flowing channel will flow with the ('rapidly' flowing) water but will be retarded by diffusion down into the backfill again. This down diffusion retards the nuclide migration

Flow and solute transport in backfilled tunnel and collapsed backfill - possible extension of Comp32

Energy Technology Data Exchange (ETDEWEB)

Neretnieks, Ivars [Royal Inst. of Technology, Stockholm (Sweden). Dept. of Chemical Engineering and Technology

2006-09-15

In the Swedish deep geological final repository for spent fuel the tunnels will be filled with a backfill with low permeability. However, some flow may take place in the backfill. Nuclides released from a leaking canister could diffuse up to the flowing water in the backfill and be transported downstream in the tunnel. At an intersection of the tunnel with a fracture zone the contaminated water might flow out into the zone.This report addresses the transport mechanisms and rate of transport from a leaking canister up through the buffer and backfill in the deposition hole, further into the backfill in the tunnel and the transport along the tunnel. Spreading by diffusion in the buffer and backfill as well as retardation of sorbing nuclides is accounted for.The transport mechanisms and rates of transport are described and some simple models with analytical solutions are used to quantify the processes. These simple solutions are used to gain insights into when different transport mechanisms are important. The simple solutions are used to simulate a base case example where a non-sorbing nuclide (iodide) and a sorbing nuclide (radium) move in the backfill by diffusion and by advective flow. The simple sample calculations show that it would take thousands of years for iodide to move 20 m along the tunnel and that a release pulse would spread out considerably over time. The sorbing nuclide {sup 226}Ra with a half life of 1,600 years would be strongly retarded by sorption and would decay to insignificance during its migration along the tunnel. The consequences of a collapse of backfill leaving a channel above the backfill is also studied by a simple analytical model that accounts for water flowing in the collapsed part of the backfill at the ceiling of the tunnel. A nuclide that diffuses up to the flowing channel will flow with the ('rapidly' flowing) water but will be retarded by diffusion down into the backfill again. This down diffusion retards the nuclide

Proton tunneling in solids

Energy Technology Data Exchange (ETDEWEB)

Kondo, J.

1998-10-01

The tunneling rate of the proton and its isotopes between interstitial sites in solids is studied theoretically. The phonons and/or the electrons in the solid have two effects on the tunneling phenomenon. First, they suppress the transfer integral between two neighbouring states. Second, they give rise to a finite lifetime of the proton state. Usually the second effect is large and the tunneling probability per unit time (tunneling rate) can be defined. In some cases, however, a coherent tunneling is expected and actually observed. (author)

Proton tunneling in solids

International Nuclear Information System (INIS)

Kondo, J.

1998-01-01

The tunneling rate of the proton and its isotopes between interstitial sites in solids is studied theoretically. The phonons and/or the electrons in the solid have two effects on the tunneling phenomenon. First, they suppress the transfer integral between two neighbouring states. Second, they give rise to a finite lifetime of the proton state. Usually the second effect is large and the tunneling probability per unit time (tunneling rate) can be defined. In some cases, however, a coherent tunneling is expected and actually observed. (author)

Relationship between Smoking and Outcomes after Cubital Tunnel Release.

Science.gov (United States)

Crosby, Nicholas E; Nosrati, Naveed N; Merrell, Greg; Hasting, Hill

2018-04-01

Several studies have drawn a connection between cigarette smoking and cubital tunnel syndrome. One comparison article demonstrated worse outcomes in smokers treated with transmuscular transposition of the ulnar nerve. However, very little is known about the effect that smoking might have on patients who undergo ulnar nerve decompression at the elbow. The purpose of this study is to evaluate the effect of smoking preoperatively on outcomes in patients treated with ulnar nerve decompression. This study used a survey developed from the comparison article with additional questions based on outcome measures from supportive literature. Postoperative improvement was probed, including sensation, strength, and pain scores. A thorough smoking history was obtained. The study spanned a 10-year period. A total of 1,366 surveys were mailed to former patients, and 247 surveys with adequate information were returned. No significant difference was seen in demographics or comorbidities. Patients who smoked preoperatively were found to more likely relate symptoms of pain. Postoperatively, nonsmoking patients generally reported more favorable improvement, though these findings were not statistically significant. This study finds no statistically significant effect of smoking on outcomes after ulnar nerve decompression. Finally, among smokers, there were no differences in outcomes between simple decompression and transposition.

Microleakage, adaptation ability and clinical efficacy of two fluoride releasing fissure sealants

Directory of Open Access Journals (Sweden)

Marković Dejan

2012-01-01

Full Text Available Background/Aim. Retention of fissure sealants and good adaptation to enamel are essential for their success. Fluoride releasing resin-based materials are widely accepted for pit and fissure sealing, but newly designed glass ionomers can serve as a good alternative. The aim of this study was to evaluate microleakage and sealing ability in vitro, and to clinically assess two fluoride releasing fissure sealants. Methods. The sample for experimental study consisted of 20 freshly extracted intact human third molars, divided in two experimental groups according to the sealing material: fluoride releasing resin-based (Heliosel F and glass ionomer (Fuji Triage material. Digital images and scanning electron microscope were used to assess microleakage and adaptation ability. Sample for clinical study consisted of 60 children, aged 6-8 years, with high caries risk, divided in two groups according to the sealant material. Fissure sealant was applied to all erupted, caries-free first permanent molars. Sealants were evaluated after 3, 6 and 12 months using modified Ryge criteria for retention, marginal adaptation, colour match, surface smoothness and caries. Results. Microleakage was detected in more than half of the specimen, without significant differences between the two groups (p > 0.05. Both materials exhibited acceptable sealing ability. Complete retention at the end of the observation period was 81.8% for resin-based, and 21.1% for glass-ionomer fissure sealant (p < 0.001. The presence of caries in sealed molars has been detected in one patient in both groups. During the 12-month observation period, Helioseal F demonstrated better retention, marginal adaptation and surface smoothness (p < 0.001. There were no differences between the two materials regarding caries and color match (p > 0.05. Conclusion. Both tested materials demonstrate satisfactory clinical and caries prophylactic characteristics that justify their use in contemporary preventive

Smoke flow temperature beneath tunnel ceiling for train fire at subway station: Reduced-scale experiments and correlations

International Nuclear Information System (INIS)

Meng, Na; Wang, Qiang; Liu, Zhaoxia; Li, Xiao; Yang, He

2017-01-01

Highlights: • Reduced-scale experiments on train fire at subway station. • Smoke flow temperature beneath tunnel ceiling measured and correlated. • Effect of platform-tunnel conjunction door type on smoke temperature is clarified. - Abstract: This paper is to investigate the smoke flow temperature beneath tunnel ceiling for a train on fire stopping besides a subway station. Experiments were carried out in a reduced-scale (1:10) subway station model to study the maximum smoke temperature and the longitudinal temperature distribution beneath the tunnel ceiling by considering platform-tunnel conjunction doors of two types: the full-seal platform screen door (PSD) and the full-height safety door. For the maximum temperature beneath the tunnel ceiling, it is found to be well correlated non-dimensionally with heat release rate by a 3.65 and a 2.92 power law function for the full-seal platform screen door and the full-height safety door, respectively. For the longitudinal temperature distribution along the tunnel ceiling, it can be well correlated by an exponential function for both types of platform-tunnel conjunction doors. Concerning the effect of the door type, the maximum temperature is lower and the longitudinal temperature decays faster for full-height safety door than that for full-seal PSD. This is due to that with the full-height safety door, the effective width of the tunnel ceiling is widened, which results in more heat losses from the smoke flow to the ceiling.

Fluctuation Dominated Josephson Tunneling with a Scanning Tunneling Microscope

International Nuclear Information System (INIS)

Naaman, O.; Teizer, W.; Dynes, R. C.

2001-01-01

We demonstrate Josephson tunneling in vacuum tunnel junctions formed between a superconducting scanning tunneling microscope tip and a Pb film, for junction resistances in the range 50--300 k Omega. We show that the superconducting phase dynamics is dominated by thermal fluctuations, and that the Josephson current appears as a peak centered at small finite voltage. In the presence of microwave fields (f=15.0 GHz) the peak decreases in magnitude and shifts to higher voltages with increasing rf power, in agreement with theory

The ISI Tunnel

Science.gov (United States)

1993-10-01

DP /etc/tunnelvisa p zephyr dark -star TCP /etc/tunnelvisa p zephyr dak’star ICMP /etc/tunnelvisa p zephyr quark MDP /etc/tunnelvisa p zephyr quark ...drax-net-yp 128.9.32.2 1 route add quark -net-yp 128.9.32.3 1 route add vlsi-net-yp 128.9.32.4 1 route add darkstar-net-yp 128.9.32.3 1 route add rocky...TCP /etc/tunnel-visa p zephyr quark ICMP /etc/tunnel-visa p zephyr drax tTI)P /etc/tunnel-visa p zephyr drax TCP /etc/tunnel_visa p zephyr drax ICMP

Resonant tunnel magnetoresistance in a double magnetic tunnel junction

KAUST Repository

Useinov, Arthur; Useinov, Niazbeck Kh H; Tagirov, Lenar R.; Kosel, Jü rgen

2011-01-01

We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can

Tunneling through landsliding zone; Jisuberi chitainai no tunnel seko

Energy Technology Data Exchange (ETDEWEB)

Konbu, A; Hatabu, K; Kano, T [Tekken Corp., Tokyo (Japan)

1994-08-01

At the new tunnel construction site of the Shirakata tunnel on the Obama line in Yamaguchi Prefecture, a landsliding occurred at about 60 meters to the upper portion obliquely to the right hand side of the shaft when the excavation progressed to about 10 meters from the starting side. The landslide caused displacement at the shaft opening and change in the supports. As a result of the re-investigation, it was confirmed that the slide face went through the tunnel cross section. The measures taken were removal of the upper soil and an adoption of the all ground fastening (AGF) method (injection type long tip fastening method) as an auxiliary construction to stop loosening of the natural ground associated with the tunnel excavation. The result was a completion of tunneling the landsliding zone without a problem. This paper reports the AGF method adopted in the above construction, together with the construction works and natural ground conditions. The AGF method is about the same as the pipe roof method with regard to the natural ground accepting mechanism and the materials used. The difference is building an improved body in a limited area in the natural ground around the steel pipes by injecting the fixing material. The use of this method caused no problems in subsidence and displacement in the surrounding ground, and completed the tunneling construction without an unusual event. 1 ref., 7 figs., 2 tabs.

Carpal Tunnel Syndrome in Aberrant Muscle Syndrome: A Case Report and Review of the Literature.

Science.gov (United States)

Steele, Jessica; Coombs, Christopher

2018-06-01

Aberrant Muscle Syndrome (AMS) is a rare congenital hand difference that is characterised by unilateral non-progressive muscular hyperplasia. The aetiology of aberrant muscle syndrome is not known, but a recently published case has shown a somatic PIK3CA activating mutation in a patient with AMS. Carpal tunnel syndrome (CTS) in children is rare. The most common causes are the mucopolysaccaridoses but space-occupying lesions have also been reported to cause CTS in children. We report the first case of CTS in a child with AMS successfully treated with open carpal tunnel release and excision of aberrant muscles.

The Mechanical and Fracturing of Rockburst in Tunnel and Its Acoustic Emission Characteristics

Directory of Open Access Journals (Sweden)

Xiangxin Liu

2018-01-01

Full Text Available The phenomenon of acoustic emission (AE is associated with rock failure and rock fracturing. In order to investigate the influence of tectonic stress on rockburst in tunnel, a biaxial loading experiment system was used in this study. The excavation operation is undertaken at the center of samples to monitor the tunnel forming process in situ, and the different horizontal stresses can be studied by using the AE monitoring technique. The dynamical fracturing process of the tunnel model was summarized, and the timing parameters of AE signals in rockburst stages were obtained. The curves of AE energy and cumulative AE energy with time show a “step-like” rising trend before the occurrence of rockburst. The evolution of macro- and mesocracks is captured, and the mechanical conditions for a “V-shaped” rockburst pit are derived. As the horizontal stress increases, the effect of excavation unloading becomes more pronounced, and the damage caused by the rockburst intensifies. In the early stage of rockburst evolution, the fracturing type follows a model of tensile-shear mix model. A positive relationship between the ratio of shear fracturing type and the horizontal stress can be noted when the rock is about to burst, and the high intensity and the high energy released of from the rock-fracturing event have become evident. Thus, the results indicate that one should focus on monitoring both sides of the surrounding rock of the tunnel so as to extract the characteristics of the process of tunnel in tunnel. The applications of biaxial loading system and during an excavation operation provide a useful tool to simulate the rock burst in tunnel at an engineering site.

Development of the tunneling junction simulation environment for scanning tunneling microscope evaluation

International Nuclear Information System (INIS)

Gajewski, Krzysztof; Piasecki, Tomasz; Kopiec, Daniel; Gotszalk, Teodor

2017-01-01

Proper configuration of scanning tunneling microscope electronics plays an important role in the atomic scale resolution surface imaging. Device evaluation in the tunneling contact between scanning tip and sample may be prone to the surface quality or mechanical disturbances. Thus the use of tunneling junction simulator makes electronics testing more reliable and increases its repeatability. Here, we present the theoretical background enabling the proper selection of electronic components circuitry used as a tunneling junction simulator. We also show how to simulate mechanics related to the piezoelectric scanner, which is applied in real experiments. Practical use of the proposed simulator and its application in metrological characterization of the developed scanning tunneling microscope is also shown. (paper)

Biocell Training course mandatory for accessing the LHC tunnel from 1 December 2010

CERN Multimedia

CERN Bulletin

2010-01-01

Following the incident in Sector 3-4 on 19 September 2008, which led to a major helium release in the LHC tunnel, measures have been put in place to reinforce safety awareness and training for all those accessing the tunnel.   One of the actions taken was to create a hands-on safety course on how to put the Self Rescue Breathing Apparatus (Biocell) on. The course is entitled “Biocell Training” and started late summer 2009. To date some 1350 people have been trained, although roughly 1700 people have access to the LHC machine tunnel. With the training capacity in place, it is feasible to train everyone with access before the coming Christmas technical stop, which will start in December 2010. The “Biocell Training” course has clearly shown the necessity of training the personnel. In addition, the feedback from the participants is very positive. Decision In the light of the conclusion reached by HSE, DSOs and the GLIMOS of the LHC experiments, successful comple...

Fabrication of magnetic tunnel junctions with a single-crystalline LiF tunnel barrier

Science.gov (United States)

Krishna Narayananellore, Sai; Doko, Naoki; Matsuo, Norihiro; Saito, Hidekazu; Yuasa, Shinji

2018-04-01

We fabricated Fe/LiF/Fe magnetic tunnel junctions (MTJs) by molecular beam epitaxy on a MgO(001) substrate, where LiF is an insulating tunnel barrier with the same crystal structure as MgO (rock-salt type). Crystallographical studies such as transmission electron microscopy and nanobeam electron diffraction observations revealed that the LiF tunnel barrier is single-crystalline and has a LiF(001)[100] ∥ bottom Fe(001)[110] crystal orientation, which is constructed in the same manner as MgO(001) on Fe(001). Also, the in-plane lattice mismatch between the LiF tunnel barrier and the Fe bottom electrode was estimated to be small (about 0.5%). Despite such advantages for the tunnel barrier of the MTJ, the observed tunnel magnetoresistance (MR) ratio was low (˜6% at 20 K) and showed a significant decrease with increasing temperature (˜1% at room temperature). The results imply that indirect tunneling and/or thermally excited carriers in the LiF tunnel barrier, in which the current basically is not spin-polarized, play a major role in electrical transport in the MTJ.

Resonant tunneling via spin-polarized barrier states in a magnetic tunnel junction

NARCIS (Netherlands)

Jansen, R.; Lodder, J.C.

2000-01-01

Resonant tunneling through states in the barrier of a magnetic tunnel junction has been analyzed theoretically for the case of a spin-polarized density of barrier states. It is shown that for highly spin-polarized barrier states, the magnetoresistance due to resonant tunneling is enhanced compared

Quantum tunneling time

International Nuclear Information System (INIS)

Wang, Z.S.; Lai, C.H.; Oh, C.H.; Kwek, L.C.

2004-01-01

We present a calculation of quantum tunneling time based on the transition duration of wave peak from one side of a barrier to the other. In our formulation, the tunneling time comprises a real and an imaginary part. The real part is an extension of the phase tunneling time with quantum corrections whereas the imaginary time is associated with energy derivatives of the probability amplitudes

Outcome and clinical signs of arthroscopically graded patellar chondromalacia with or without lateral release.

Science.gov (United States)

Korkala, O L; Isotalo, T M; Lavonius, M I; Niskanen, R O

1995-01-01

In a follow-up study of 67 patients with an arthroscopically diagnosed patellar chondromalacia, we compared the results of plain conservative treatment with those after an open lateral retinacular release. The mean follow-up was 35 months. In Grade I chondromalacia the lateral release did not affect the result, which was in all cases good or excellent. In Grade II to IV chondromalacia the lateral release appeared beneficial, although the difference did not reach statistical significance. We also examined the validity of three clinical signs in arthroscopically verified patellar chondromalacia. Patellar inhibition and tracking tests were clearly more sensitive than the lateral apprehension test, which often gave a false negative result. If the patellar inhibition test is positive and a Grade II to IV chondromalacia of the patella is found at arthroscopy, lateral release should be considered among other procedures, like patellar shaving or patellar resurfacing.

Microwave-induced co-tunneling in single electron tunneling transistors

DEFF Research Database (Denmark)

Ejrnaes, M.; Savolainen, M.; Manscher, M.

2002-01-01

on rubber bellows. Cross-talk was minimized by using individual coaxial lines between the sample and the room temperature electronics: The co-tunneling experiments were performed at zero DC bias current by measuring the voltage response to a very small amplitude 2 Hz current modulation with the gate voltage......The influence of microwaves on the co-tunneling in single electron tunneling transistors has been investigated as function of frequency and power in the temperature range from 150 to 500 mK. All 20 low frequency connections and the RF line were filtered, and the whole cryostat was suspended...

Current evidence for effectiveness of interventions for cubital tunnel syndrome, radial tunnel syndrome, instability, or bursitis of the elbow: a systematic review.

Science.gov (United States)

Rinkel, Willem D; Schreuders, Ton A R; Koes, Bart W; Huisstede, Bionka M A

2013-12-01

To provide an evidence-based overview of the effectiveness of interventions for 4 nontraumatic painful disorders sharing the anatomic region of the elbow: cubital tunnel syndrome, radial tunnel syndrome, elbow instability, and olecranon bursitis. The Cochrane Library, PubMed, Embase, PEDro, and CINAHL were searched to identify relevant reviews and randomized clinical trials (RCTs). Two reviewers independently extracted data and assessed the quality of the methodology. A best-evidence synthesis was used to summarize the results. One systematic review and 6 RCTs were included. For the surgical treatment of cubital tunnel syndrome (1 review, 3 RCTs), comparing simple decompression with anterior ulnar nerve transposition, no evidence was found in favor of either one of these. Limited evidence was found in favor of medial epicondylectomy versus anterior transposition and for early postoperative therapy versus immobilization. No evidence was found for the effect of local steroid injection in addition to splinting. No RCTs were found for radial tunnel syndrome. For olecranon bursitis (1 RCT), limited evidence for effectiveness was found for methylprednisolone acetate injection plus naproxen. Concerning elbow instability, including 2 RCTs, one showed that nonsurgical treatment resulted in similar results compared with surgery, whereas the other found limited evidence for the effectiveness in favor of early mobilization versus 3 weeks of immobilization after surgery. In this review no, or at best, limited evidence was found for the effectiveness of nonsurgical and surgical interventions to treat painful cubital tunnel syndrome, radial tunnel syndrome, elbow instability, or olecranon bursitis. Well-designed and well-conducted RCTs are clearly needed in this field.

Influence of trap-assisted tunneling on trap-assisted tunneling current in double gate tunnel field-effect transistor

International Nuclear Information System (INIS)

Jiang Zhi; Zhuang Yi-Qi; Li Cong; Wang Ping; Liu Yu-Qi

2016-01-01

Trap-assisted tunneling (TAT) has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor (TFET). In this paper, we assess subthreshold performance of double gate TFET (DG-TFET) through a band-to-band tunneling (BTBT) model, including phonon-assisted scattering and acoustic surface phonons scattering. Interface state density profile (D it ) and the trap level are included in the simulation to analyze their effects on TAT current and the mechanism of gate leakage current. (paper)

Thermovoltages in vacuum tunneling investigated by scanning tunneling microscopy

OpenAIRE

Hoffmann, D. H.; Rettenberger, Armin; Grand, Jean Yves; Läuger, K.; Leiderer, Paul; Dransfeld, Klaus; Möller, Rolf

1995-01-01

By heating the tunneling tip of a scanning tunneling microscope the thermoelectric properties of a variable vacuum barrier have been investigated. The lateral variation of the observed thermovoltage will be discussed for polycrystalline gold, stepped surfaces of silver, as well as for copper islands on silver.

Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

International Nuclear Information System (INIS)

Cleland, A.N.

1991-04-01

Experiments investigating the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very small capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters; the tunneling rate in the moderately damped (Q ∼ 1) junction is seen to be reduced by a factor of 300 from that predicted for an undamped junction. The phase is seen to be a good quantum-mechanical variable. The experiments on small capacitance tunnel junctions extend the measurements on the larger-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wavefunction has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias. I present the first clear observation of the Coulomb blockade in single junctions. The electrical environment of the tunnel junction, however, strongly affects the behavior of the junction: higher resistance leads are observed to greatly sharpen the Coulomb blockade over that seen with lower resistance leads. I present theoretical descriptions of how the environment influences the junctions; comparisons with the experimental results are in reasonable agreement

HELB Analysis for ESBWR Reactor Building and Main Steam Tunnel

Energy Technology Data Exchange (ETDEWEB)

Noguera Oliva, O.

2011-07-01

The Reactor Building compartments and tbe Main Steam Tunnel are modeled using GOTHIC 7.2a. These models are based on Control Volumes (Rooms/Compartments/Regions), Flow Paths (junctions such as vent path or any opening) and Boundary Conditions (Mass and energy releases and outside conditions). Due to the different break locations, four models are built to analyze the short-term pressurization response. Are shown the cases analyzed, the results obtained and the models used for this purpose.

About tunnelling times

International Nuclear Information System (INIS)

Olkhovsky, V.S.; Recami, E.

1991-08-01

In this paper, first we critically analyse the main theoretical definitions and calculations of the sub-barrier tunnelling and reflection times. Secondly, we propose a new, physically sensible definition of such durations, on the basis of a recent general formalism (already tested for other types of quantum collisions). At last, we discuss some results regarding temporal evolution of the tunnelling processes, and in particular the ''particle'' speed during tunnelling. (author). 36 refs, 1 fig

Local Fission Gas Release and Swelling in Water Reactor Fuel during Slow Power Transients

DEFF Research Database (Denmark)

Mogensen, Mogens Bjerg; Walker, C.T.; Ray, I.L.F.

1985-01-01

Gas release and fuel swelling caused by a power increase in a water reactor fuel (burn-up 2.7–4.5% FIMA) is described. At a bump terminal level of about 400 W/cm (local value) gas release was 25–40%. The formation of gas bubbles on grain boundaries and their degree of interlinkage are the two...... factors that determine the level of fission gas release during a power bump. Release begins when gas bubbles on grain boundaries start o interlink. This occurred at r/r0 ~ 0.75. Release tunnels were fully developed at r/r0 ~ 0.55 with the result that gas release was 60–70% at this position....

Analytical Solution of Tunnel Surrounding Rock for Stress and Displacement Based on Lade–Duncan Criterion

Directory of Open Access Journals (Sweden)

MingZheng Zhu

2018-01-01

Full Text Available The deformation and failure of tunnel surrounding rock is the result of tunnel excavation disturbance and rock stress release. When the local stress of surrounding rock exceeds the elastic limit of rock mass, the plastic analysis of surrounding rock must be carried out to judge the stability of tunnel. In this study, the Lade–Duncan yield criterion is used to calculate the analytic solutions for the surrounding rock in a tunnel, and the radius and displacement of the plastic zone are deduced using an equilibrium equation. The plastic zone radius and displacement based on Lade–Duncan criterion and Mohr–Coulomb criterion were compared by using single-factor analysis method under the different internal friction angles, in situ stresses, and support resistances. The results show that the solutions of the radius and displacement of plastic zone calculated by the Lade–Duncan criterion are close to those of Mohr–Coulomb criterion under the high internal friction angle and support resistance or low in situ rock stress; however, the radius and displacement of the plastic zone calculated by the Lade–Duncan criterion are larger under normal circumstances, and the Lade–Duncan criterion is more applicable to the stability analysis of the surrounding rock in a tunnel.

Tunneling current between graphene layers

OpenAIRE

Poklonski, Nikolai A.; Siahlo, Andrei I.; Vyrko, Sergey A.; Popov, Andrey M.; Lozovik, Yurii E.

2013-01-01

The physical model that allows to calculate the values of the tunneling current be-tween graphene layers is proposed. The tunneling current according to the pro-posed model is proportional to the area of tunneling transition. The calculated value of tunneling conductivity is in qualitative agreement with experimental data.

Single Electron Tunneling

International Nuclear Information System (INIS)

Ruggiero, Steven T.

2005-01-01

Financial support for this project has led to advances in the science of single-electron phenomena. Our group reported the first observation of the so-called ''Coulomb Staircase'', which was produced by tunneling into ultra-small metal particles. This work showed well-defined tunneling voltage steps of width e/C and height e/RC, demonstrating tunneling quantized on the single-electron level. This work was published in a now well-cited Physical Review Letter. Single-electron physics is now a major sub-field of condensed-matter physics, and fundamental work in the area continues to be conducted by tunneling in ultra-small metal particles. In addition, there are now single-electron transistors that add a controlling gate to modulate the charge on ultra-small photolithographically defined capacitive elements. Single-electron transistors are now at the heart of at least one experimental quantum-computer element, and single-electron transistor pumps may soon be used to define fundamental quantities such as the farad (capacitance) and the ampere (current). Novel computer technology based on single-electron quantum dots is also being developed. In related work, our group played the leading role in the explanation of experimental results observed during the initial phases of tunneling experiments with the high-temperature superconductors. When so-called ''multiple-gap'' tunneling was reported, the phenomenon was correctly identified by our group as single-electron tunneling in small grains in the material. The main focus throughout this project has been to explore single electron phenomena both in traditional tunneling formats of the type metal/insulator/particles/insulator/metal and using scanning tunneling microscopy to probe few-particle systems. This has been done under varying conditions of temperature, applied magnetic field, and with different materials systems. These have included metals, semi-metals, and superconductors. Amongst a number of results, we have

Drill and blast tunnelling; Konvensjonell drift av tunneler

Energy Technology Data Exchange (ETDEWEB)

Roenn, Paal-Egil

1997-12-31

This thesis treats drill and blast tunnelling. The rapid technological advance necessitates revised and updated design criteria, quality requirements and quality control. In situ blast experiments were carried out in order to test new methods and improve the basis for calculation and design. The main topics of the experiments were (1) longer rounds and increased drillhole diameter, (2) emulsion slurry as explosives in tunnelling, and (3) electronic detonators in contour blasting. The experiments show that it is technically feasible to blast rounds of up to 8.6 m length. Using current technology, the economical optimum round length is substantially shorter. Dust, low visibility, noise and toxic fumes are occupational environmental strains for the tunnel workers. Several of the environmental factors are strongly influenced by the type of explosives used. For example, emulsion slurry resulted in 4 to 5 times better visibility than Anolit and the concentration of respirable dust and total dust was reduced by 30-50 %. Electronic detonators were tested and found to give a higher percentage of remaining drillholes in the contour than Nonel detonators. The thesis includes a chapter on economic design of hydropower tunnels. 42 refs., 83 figs., 45 tabs.

Resonant tunnel magnetoresistance in double-barrier planar magnetic tunnel junctions

KAUST Repository

Useinov, A. N.

2011-08-24

We present a theoretical approach to calculate the spin-dependent current and tunnel magnetoresistance (TMR) in a double-barrier magnetic tunnel junction (DMTJ), in which the magnetization of the middle ferromagnetic metal layer can be aligned parallel or antiparallel in relation to the fixed magnetizations of the left and right ferromagnetic electrodes. The electron transport through the DMTJ is considered as a three-dimensional problem, taking into account all transmitting electron trajectories as well as the spin-dependent momentum conservation law. The dependence of the transmission coefficient and spin-polarized currents on the applied voltage is derived as an exact solution to the quantum-mechanical problem for the spin-polarized transport. In the range of the developed physical model, the resonant tunneling, nonresonant tunneling, and enhanced spin filtering can be explained; the simulation results are in good agreement with experimental data.

Resonant tunnel magnetoresistance in double-barrier planar magnetic tunnel junctions

KAUST Repository

Useinov, A. N.; Kosel, Jü rgen; Useinov, N. Kh.; Tagirov, L. R.

2011-01-01

We present a theoretical approach to calculate the spin-dependent current and tunnel magnetoresistance (TMR) in a double-barrier magnetic tunnel junction (DMTJ), in which the magnetization of the middle ferromagnetic metal layer can be aligned parallel or antiparallel in relation to the fixed magnetizations of the left and right ferromagnetic electrodes. The electron transport through the DMTJ is considered as a three-dimensional problem, taking into account all transmitting electron trajectories as well as the spin-dependent momentum conservation law. The dependence of the transmission coefficient and spin-polarized currents on the applied voltage is derived as an exact solution to the quantum-mechanical problem for the spin-polarized transport. In the range of the developed physical model, the resonant tunneling, nonresonant tunneling, and enhanced spin filtering can be explained; the simulation results are in good agreement with experimental data.

Quantum size effects on spin-tunneling time in a magnetic resonant tunneling diode

OpenAIRE

Saffarzadeh, Alireza; Daqiq, Reza

2009-01-01

We study theoretically the quantum size effects of a magnetic resonant tunneling diode (RTD) with a (Zn,Mn)Se dilute magnetic semiconductor layer on the spin-tunneling time and the spin polarization of the electrons. The results show that the spin-tunneling times may oscillate and a great difference between the tunneling time of the electrons with opposite spin directions can be obtained depending on the system parameters. We also study the effect of structural asymmetry which is related to t...

Drug release, preclinical and clinical pharmacokinetics relationships of alginate pellets prepared by melt technology.

Science.gov (United States)

Bose, Anirbandeep; Harjoh, Nurulaini; Pal, Tapan Kumar; Dan, Shubhasis; Wong, Tin Wui

2016-01-01

Alginate pellets prepared by the aqueous agglomeration technique experience fast drug dissolution due to the porous pre-formed calcium alginate microstructure. This study investigated in vitro drug release, preclinical and clinical pharmacokinetics relationships of intestinal-specific calcium acetate-alginate pellets against calcium-free and calcium carbonate-alginate pellets. Alginate pellets were prepared by solvent-free melt pelletization instead of aqueous agglomeration technique using chlorpheniramine maleate as model drug. A fast in situ calcium acetate dissolution in pellets resulted in rapid pellet breakup, soluble Ca(2+) crosslinking of alginate fragments and drug dissolution retardation at pH 1.2, which were not found in other pellet types. The preclinical drug absorption rate was lower with calcium acetate loaded than calcium-free alginate pellets. In human subjects, however, the extent and the rate of drug absorption were higher from calcium acetate-loaded pellets than calcium-free alginate pellets. The fine, dispersible and weakly gastric mucoadhesive calcium alginate pellets underwent fast human gastrointestinal transit. They released the drug at a greater rate than calcium-free pellets in the intestine, thereby promoting drug bioavailability. Calcium acetate was required as a disintegrant more than as a crosslinking agent clinically to promote pellet fragmentation, fast gastrointestinal transit and drug release in intestinal medium, and intestinal-specific drug bioavailability.

Influence of trap-assisted tunneling on trap-assisted tunneling current in double gate tunnel field-effect transistor

Science.gov (United States)

Zhi, Jiang; Yi-Qi, Zhuang; Cong, Li; Ping, Wang; Yu-Qi, Liu

2016-02-01

Trap-assisted tunneling (TAT) has attracted more and more attention, because it seriously affects the sub-threshold characteristic of tunnel field-effect transistor (TFET). In this paper, we assess subthreshold performance of double gate TFET (DG-TFET) through a band-to-band tunneling (BTBT) model, including phonon-assisted scattering and acoustic surface phonons scattering. Interface state density profile (Dit) and the trap level are included in the simulation to analyze their effects on TAT current and the mechanism of gate leakage current. Project supported by the National Natural Science Foundation of China (Grant Nos. 61574109 and 61204092).

Study of tunneling transport in Si-based tunnel field-effect transistors with ON current enhancement utilizing isoelectronic trap

Science.gov (United States)

Mori, Takahiro; Morita, Yukinori; Miyata, Noriyuki; Migita, Shinji; Fukuda, Koichi; Mizubayashi, Wataru; Masahara, Meishoku; Yasuda, Tetsuji; Ota, Hiroyuki

2015-02-01

The temperature dependence of the tunneling transport characteristics of Si diodes with an isoelectronic impurity has been investigated in order to clarify the mechanism of the ON-current enhancement in Si-based tunnel field-effect transistors (TFETs) utilizing an isoelectronic trap (IET). The Al-N complex impurity was utilized for IET formation. We observed three types of tunneling current components in the diodes: indirect band-to-band tunneling (BTBT), trap-assisted tunneling (TAT), and thermally inactive tunneling. The indirect BTBT and TAT current components can be distinguished with the plot described in this paper. The thermally inactive tunneling current probably originated from tunneling consisting of two paths: tunneling between the valence band and the IET trap and tunneling between the IET trap and the conduction band. The probability of thermally inactive tunneling with the Al-N IET state is higher than the others. Utilization of the thermally inactive tunneling current has a significant effect in enhancing the driving current of Si-based TFETs.

Electrical installations of the Channel tunnel; Installations electriques du Tunnel sous la Manche

Energy Technology Data Exchange (ETDEWEB)

Kersabiec, G. de [Eurotunnel, Folkestone (United Kingdom)

2002-08-01

Like an underground factory, the railway and auxiliary equipments of the Channel tunnel between France and UK, need a reliable and redundant power supply with a high quality maintenance. This article presents: the design criteria of the power distribution systems, the installation itself and the organisation of its exploitation: 1 - transportation system of the Channel tunnel (loads to supply, exploitation imperatives, fundamental criteria); 2 - external power sources (connection to the UK and French grids, values used by the national grids); 3 - exploitation criteria, tunnel design; 4 - description (main UK and French power stations, 25 kV traction network, 21 kV distribution network, tunnels, lighting in railway tunnels, supply of terminals, earthing network); 5 - exploitation; 6 - maintenance and quality. (J.S.)

Heavy-Atom Tunneling Calculations in Thirteen Organic Reactions: Tunneling Contributions are Substantial, and Bell's Formula Closely Approximates Multidimensional Tunneling at ≥250 K.

Science.gov (United States)

Doubleday, Charles; Armas, Randy; Walker, Dana; Cosgriff, Christopher V; Greer, Edyta M

2017-10-09

Multidimensional tunneling calculations are carried out for 13 reactions, to test the scope of heavy-atom tunneling in organic chemistry, and to check the accuracy of one-dimensional tunneling models. The reactions include pericyclic, cycloaromatization, radical cyclization and ring opening, and S N 2. When compared at the temperatures that give the same effective rate constant of 3×10 -5  s -1 , tunneling accounts for 25-95 % of the rate in 8 of the 13 reactions. Values of transmission coefficients predicted by Bell's formula, κ Bell  , agree well with multidimensional tunneling (canonical variational transition state theory with small curvature tunneling), κ SCT . Mean unsigned deviations of κ Bell vs. κ SCT are 0.08, 0.04, 0.02 at 250, 300 and 400 K. This suggests that κ Bell is a useful first choice for predicting transmission coefficients in heavy-atom tunnelling. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Macroscopic quantum tunneling in Josephson tunnel junctions and Coulomb blockade in single small tunnel junctions

International Nuclear Information System (INIS)

Cleland, A.N.

1991-01-01

Experiments investigated the process of macroscopic quantum tunneling in a moderately-damped, resistively shunted, Josephson junction are described, followed by a discussion of experiments performed on very-small-capacitance normal-metal tunnel junctions. The experiments on the resistively-shunted Josephson junction were designed to investigate a quantum process, that of the tunneling of the Josephson-phase variable under a potential barrier, in a system in which dissipation plays a major role in the dynamics of motion. All the parameters of the junction were measured using the classical phenomena of thermal activation and resonant activation. Theoretical predictions are compared with the experimental results, showing good agreement with no adjustable parameters. The experiments on small-capacitance tunnel junctions extend the measurements on the large-area Josephson junctions from the region in which the phase variable has a fairly well-defined value, i.e. its wave function has a narrow width, to the region where its value is almost completely unknown. The charge on the junction becomes well-defined and is predicted to quantize the current through the junction, giving rise to the Coulomb blockade at low bias

Tunneling rates in electron transport through double-barrier molecular junctions in a scanning tunneling microscope.

Science.gov (United States)

Nazin, G V; Wu, S W; Ho, W

2005-06-21

The scanning tunneling microscope enables atomic-scale measurements of electron transport through individual molecules. Copper phthalocyanine and magnesium porphine molecules adsorbed on a thin oxide film grown on the NiAl(110) surface were probed. The single-molecule junctions contained two tunneling barriers, vacuum gap, and oxide film. Differential conductance spectroscopy shows that electron transport occurs via vibronic states of the molecules. The intensity of spectral peaks corresponding to the individual vibronic states depends on the relative electron tunneling rates through the two barriers of the junction, as found by varying the vacuum gap tunneling rate by changing the height of the scanning tunneling microscope tip above the molecule. A simple, sequential tunneling model explains the observed trends.

Vacuum phonon tunneling.

Science.gov (United States)

Altfeder, Igor; Voevodin, Andrey A; Roy, Ajit K

2010-10-15

Field-induced phonon tunneling, a previously unknown mechanism of interfacial thermal transport, has been revealed by ultrahigh vacuum inelastic scanning tunneling microscopy (STM). Using thermally broadened Fermi-Dirac distribution in the STM tip as in situ atomic-scale thermometer we found that thermal vibrations of the last tip atom are effectively transmitted to sample surface despite few angstroms wide vacuum gap. We show that phonon tunneling is driven by interfacial electric field and thermally vibrating image charges, and its rate is enhanced by surface electron-phonon interaction.

Breaking through the tranfer tunnel

CERN Document Server

Laurent Guiraud

2001-01-01

This image shows the tunnel boring machine breaking through the transfer tunnel into the LHC tunnel. Proton beams will be transferred from the SPS pre-accelerator to the LHC at 450 GeV through two specially constructed transfer tunnels. From left to right: LHC Project Director, Lyn Evans; CERN Director-General (at the time), Luciano Maiani, and Director for Accelerators, Kurt Hubner.

New Tunneling Features in Polar III-Nitride Resonant Tunneling Diodes

Directory of Open Access Journals (Sweden)

Jimy Encomendero

2017-10-01

Full Text Available For the past two decades, repeatable resonant tunneling transport of electrons in III-nitride double barrier heterostructures has remained elusive at room temperature. In this work we theoretically and experimentally study III-nitride double-barrier resonant tunneling diodes (RTDs, the quantum transport characteristics of which exhibit new features that are unexplainable using existing semiconductor theory. The repeatable and robust resonant transport in our devices enables us to track the origin of these features to the broken inversion symmetry in the uniaxial crystal structure, which generates built-in spontaneous and piezoelectric polarization fields. Resonant tunneling transport enabled by the ground state as well as by the first excited state is demonstrated for the first time over a wide temperature window in planar III-nitride RTDs. An analytical transport model for polar resonant tunneling heterostructures is introduced for the first time, showing a good quantitative agreement with experimental data. From this model we realize that tunneling transport is an extremely sensitive measure of the built-in polarization fields. Since such electric fields play a crucial role in the design of electronic and photonic devices, but are difficult to measure, our work provides a completely new method to accurately determine their magnitude for the entire class of polar heterostructures.

Percutaneous Creation of Bare Intervascular Tunnels for Salvage of Thrombosed Hemodialysis Fistulas Without Recanalizable Outflow

International Nuclear Information System (INIS)

Chen, Matt Chiung-Yu; Wang, Yen-Chi; Weng, Mei-Jui

2015-01-01

PurposeThis study aimed to retrospectively assess the efficacy of a bare intervascular tunnel for salvage of a thrombosed hemodialysis fistula. We examined the clinical outcomes and provided follow-up images of the bare intervascular tunnel.Materials and MethodsEight thrombosed fistulas lacked available recanalizable outflow veins were included in this study. These fistulas were salvaged by re-directing access site flow to a new outflow vein through a percutaneously created intervascular tunnel without stent graft placement. The post-intervention primary and secondary access patency rates were calculated using the Kaplan–Meier method.ResultsThe procedural and clinical success rates were 100 %. Post-intervention primary and secondary access patency at 300 days were 18.7 ± 15.8 and 87.5 ± 11.7 %, respectively. The mean follow-up period was 218.7 days (range 10–368 days). One patient died of acute myocardial infarction 10 days after the procedure. No other major complications were observed. Minor complications, such as swelling, ecchymosis, and pain around the tunnel, occurred in all of the patients.ConclusionsPercutaneous creation of a bare intervascular tunnel is a treatment option for thrombosed hemodialysis fistulas without recanalizable outflow in selected patients

Theoretical consideration of spin-polarized resonant tunneling in magnetic tunnel junctions

International Nuclear Information System (INIS)

Mu Haifeng; Zhu Zhengang; Zheng Qingrong; Jin Biao; Wang Zhengchuan; Su Gang

2004-01-01

A recent elegant experimental realization [S. Yuasa et al., Science 297 (2002) 234] of the spin-polarized resonant tunneling in magnetic tunnel junctions is interpreted in terms of a two-band model. It is shown that the tunnel magnetoresistance (TMR) decays oscillatorily with the thickness of the normal metal (NM) layer, being fairly in agreement with the experimental observation. The tunnel conductance is found to decay with slight oscillations with the increase of the NM layer thickness, which is also well consistent with the experiment. In addition, when the magnetizations of both ferromagnet electrodes are not collinearly aligned, TMR is found to exhibit sharp resonant peaks at some particular thickness of the NM layer. The peaked TMR obeys nicely a Gaussian distribution against the relative orientation of the magnetizations

Histological Observation of Regions around Bone Tunnels after Compression of the Bone Tunnel Wall in Ligament Reconstruction

International Nuclear Information System (INIS)

Maeda, Shintaro; Ishikawa, Hiroki; Tanigawa, Naoaki; Miyazaki, Kyosuke; Shioda, Seiji

2012-01-01

The objectives of this study were to investigate the time-course of influence of compression of bone tunnel wall in ligament reconstruction on tissue around the bone tunnel and to histologically examine the mechanism of preventing the complication of bone tunnel dilation, using rabbit tibia. A model in which the femoral origin of the extensor digitorum longus tendon was cut and inserted into a bone tunnel made proximal to the tibia was prepared in the bilateral hind legs of 20 Japanese white rabbits. In each animal, a tunnel was made using a drill only in the right leg, while an undersized bone tunnel was made by drilling and then dilated by compression using a dilator to the same tunnel size as that in the right leg. Animals were sacrificed at 0, 2, 4, 8 and 12 weeks after surgery (4 animals at each time point). Observation of bone tunnels by X-ray radiography showed osteosclerosis in the 2- and 4-week dilation groups. Osteosclerosis appeared as white lines around the bone tunnel on X-ray radiography. This suggests that dilation promotes callus formation in the bone tunnel wall and prevents the complication of bone tunnel enlargement after ligament reconstruction

Analysis on ventilation pressure of fire area in longitudinal ventilation of underground tunnel

Science.gov (United States)

Li, Jiaxin; Li, Yanfeng; Feng, Xiao; Li, Junmei

2018-03-01

In order to solve the problem of ventilation pressure loss in the fire area under the fire condition, the wind pressure loss model of the fire area is established based on the thermodynamic equilibrium relation. The semi-empirical calculation formula is obtained by using the model experiment and CFD simulation. The validity of the formula is verified. The results show that the ventilation pressure loss in the fire zone is proportional to the convective heat release rate at the critical velocity, which is inversely proportional to the upstream ventilation velocity and the tunnel cross-sectional area. The proposed formula is consistent with the law of the tunnel fire test fitting formula that results are close, in contrast, the advantage lies in a clear theoretical basis and ventilation velocity values. The resistance of road tunnel ventilation system is calculated accurately and reliably, and then an effective emergency ventilation operation program is developed. It is necessary to consider the fire zone ventilation pressure loss. The proposed ventilation pressure loss formula can be used for design calculation after thorough verification.

Optimization of a tunneling barrier in magnetic tunneling junction by tilted-plasma oxidation

International Nuclear Information System (INIS)

Nam, C.H.; Shim, Heejae; Kim, K.S.; Cho, B.K.

2004-01-01

Oxidation of an AlO x insulating barrier in a magnetic tunneling junction (MTJ) was carried out by a tilted-plasma oxidation method. It was found that the tilted-plasma oxidation induced a gradual change in the extent of oxidation of an insulating layer, which consequently led to a gradual change in the tunneling magnetoresistance (TMR) and specific junction resistance (RA) of the MTJ. We found a linear relation in the TMR versus RA curve with positive and negative slopes for less- and overoxidized junctions, respectively, and a parabolic relation for optimally oxidized junctions. The crossover in the TMR versus RA curves provides an effective and useful way to optimize (and monitor) the oxidation condition of a tunneling barrier in MTJs especially of a tunneling barrier less than 10 A thick. The tunneling junctions were also investigated after thermal annealing at various temperatures. The observations after thermal annealing were found to be consistent with transmission electrons microscopy images and a scenario of the partial formation of an additional ultrathin tunneling barrier at the top surface of the bottom magnetic layer

USE OF EXTENDED-RELEASE PRAMIPEXOLE IN EARLY-STAGE PARKINSON’S DISEASE: DESCRIPTION OF A CLINICAL CASE

Directory of Open Access Journals (Sweden)

N. V. Fedorova

2014-11-01

Full Text Available The paper considers a clinical case of early-stage mixed Parkinson’s disease (PD with significant affective disorders and restless legs syndrome. Once-daily extended-release pramipexole 3 mg significantly improved a patient’s status and led to regression of movement and affective disorders. The paper gives data on the efficacy of dopamine receptor agonists in treating PD and the benefits of their extended-release formulations.

Selective deuteration illuminates the importance of tunneling in the unimolecular decay of Criegee intermediates to hydroxyl radical products.

Science.gov (United States)

Green, Amy M; Barber, Victoria P; Fang, Yi; Klippenstein, Stephen J; Lester, Marsha I

2017-11-21

Ozonolysis of alkenes, an important nonphotolytic source of hydroxyl (OH) radicals in the atmosphere, proceeds through unimolecular decay of Criegee intermediates. Here, we report a large kinetic isotope effect associated with the rate-limiting hydrogen-transfer step that releases OH radicals for a prototypical Criegee intermediate, CH 3 CHOO. IR excitation of selectively deuterated syn -CD 3 CHOO is shown to result in deuterium atom transfer and release OD radical products. Vibrational activation of syn -CD 3 CHOO is coupled with direct time-resolved detection of OD products to measure a 10-fold slower rate of unimolecular decay upon deuteration in the vicinity of the transition state barrier, which is confirmed by microcanonical statistical theory that incorporates quantum mechanical tunneling. The corresponding kinetic isotope effect of ∼10 is attributed primarily to the decreased probability of D-atom vs. H-atom transfer arising from tunneling. Master equation modeling is utilized to compute the thermal unimolecular decay rates for selectively and fully deuterated syn methyl-substituted Criegee intermediates under atmospheric conditions. At 298 K (1 atm), tunneling is predicted to enhance the thermal decay rate of syn -CH 3 CHOO compared with the deuterated species, giving rise to a significant kinetic isotope effect of ∼50.

Quantum mechanical tunneling in chemical physics

CERN Document Server

Nakamura, Hiroki

2016-01-01

Quantum mechanical tunneling plays important roles in a wide range of natural sciences, from nuclear and solid-state physics to proton transfer and chemical reactions in chemistry and biology. Responding to the need for further understanding of multidimensional tunneling, the authors have recently developed practical methods that can be applied to multidimensional systems. Quantum Mechanical Tunneling in Chemical Physics presents basic theories, as well as original ones developed by the authors. It also provides methodologies and numerical applications to real molecular systems. The book offers information so readers can understand the basic concepts and dynamics of multidimensional tunneling phenomena and use the described methods for various molecular spectroscopy and chemical dynamics problems. The text focuses on three tunneling phenomena: (1) energy splitting, or tunneling splitting, in symmetric double well potential, (2) decay of metastable state through tunneling, and (3) tunneling effects in chemical...

Mechanistic prediction of iodine and cesium release from LWR fuel

International Nuclear Information System (INIS)

Rest, J.

1983-12-01

A theoretical model (FASTGRASS) has been used for predicting the behavior of fission gas and volatile fission products (VFPs) in UO 2 -base fuels during steady-state and transient conditions. This model represents an attempt to develop an efficient predictive capability for the full range of possible reactor operating conditions. Fission products released from the fuel are assumed to reach the fuel surface by successively diffusing (via atomic and gas-bubble mobility) from the grains to grain faces and then to the grain edges, where the fission products are released through a network of interconnected tunnels of fission-gas-induced and fabricated porosity

Tunneling into quantum wires: regularization of the tunneling Hamiltonian and consistency between free and bosonized fermions

OpenAIRE

Filippone, Michele; Brouwer, Piet

2016-01-01

Tunneling between a point contact and a one-dimensional wire is usually described with the help of a tunneling Hamiltonian that contains a delta function in position space. Whereas the leading order contribution to the tunneling current is independent of the way this delta function is regularized, higher-order corrections with respect to the tunneling amplitude are known to depend on the regularization. Instead of regularizing the delta function in the tunneling Hamiltonian, one may also obta...

Tibial and Femoral Tunnel Changes After ACL Reconstruction: A Prospective 2-Year Longitudinal MRI Study.

Science.gov (United States)

Weber, Alexander E; Delos, Demetris; Oltean, Hanna N; Vadasdi, Katherine; Cavanaugh, John; Potter, Hollis G; Rodeo, Scott A

2015-05-01

Tunnel widening after anterior cruciate ligament reconstruction (ACL-R) is a well-accepted and frequent phenomenon, yet little is known regarding its origin or natural history. To prospectively evaluate the cross-sectional area (CSA) changes in tibial and femoral bone tunnels after ACL-R with serial MRI. Case series; Level of evidence, 4. Patients underwent arthroscopic ACL-R with the same surgeon, surgical technique, and rehabilitation protocol. Each patient underwent preoperative dual-energy x-ray absorptiometry and clinical evaluation, as well as postoperative time zero MRI followed by subsequent MRI and clinical examination, including functional and subjective outcome tests, at 6, 12, 24, 52, and 104 weeks. Tibial and femoral tunnel CSA was measured on each MRI at tunnel aperture (ttA and ftA), midsection (ttM and ftM), and exit (ttE and ftE). Logistic regression modeling was used to examine the predictive value of demographic data and preoperative bone quality (as measured by dual-energy x-ray absorptiometry) on functional outcome scores, manual and instrumented laxity measurements, and changes in tunnel area over time. Eighteen patients (including 12 men), mean age 35.5±8.7 years, underwent ACL-R. There was significant tunnel expansion at ttA and ftA sites 6 weeks postoperatively (P=.024 and .0045, respectively). Expansion continued for 24 weeks, with progressive tunnel narrowing thereafter. Average ttA CSA was significantly larger than ftA CSA at all times. The ttM significantly expanded after 6 weeks (P=.06); continued expansion to week 12 was followed by 21 months of reduction in tunnel diameter. The ftM and both ttE and ftE sites decreased in CSA over the 2 years. Median Lysholm and International Knee Documentation Committee scores significantly improved at final follow-up (P=.0083 and 1 year from time of injury) predicted increased tunnel widening and accelerated expansion in CSA (Pclinical outcome. Younger age, male sex, and delay from injury to ACL

Low-power laser therapy for carpal tunnel syndrome: effective optical power

Directory of Open Access Journals (Sweden)

Yan Chen

2016-01-01

Full Text Available Low-power laser therapy has been used for the non-surgical treatment of mild to moderate carpal tunnel syndrome, although its efficacy has been a long-standing controversy. The laser parameters in low-power laser therapy are closely related to the laser effect on human tissue. To evaluate the efficacy of low-power laser therapy, laser parameters should be accurately measured and controlled, which has been ignored in previous clinical trials. Here, we report the measurement of the effective optical power of low-power laser therapy for carpal tunnel syndrome. By monitoring the backside reflection and scattering laser power from human skin at the wrist, the effective laser power can be inferred. Using clinical measurements from 30 cases, we found that the effective laser power differed significantly among cases, with the measured laser reflection coefficient ranging from 1.8% to 54%. The reflection coefficient for 36.7% of these 30 cases was in the range of 10–20%, but for 16.7% of cases, it was higher than 40%. Consequently, monitoring the effective optical power during laser irradiation is necessary for the laser therapy of carpal tunnel syndrome.

Tunnelling of a molecule

International Nuclear Information System (INIS)

Jarvis, P.D.; Bulte, D.P.

1998-01-01

A quantum-mechanical description of tunnelling is presented for a one-dimensional system with internal oscillator degrees of freedom. The 'charged diatomic molecule' is frustrated on encountering a barrier potential by its centre of charge not being coincident with its centre of mass, resulting in transitions amongst internal states. In an adiabatic limit, the tunnelling of semiclassical coherent-like oscillator states is shown to exhibit the Hartman and Bueuttiker-Landauer times t H and t BL , with the time dependence of the coherent state parameter for the tunnelled state given by α(t) = α e -iω(t+Δt) , Δt = t H - it BL . A perturbation formalism is developed, whereby the exact transfer matrix can be expanded to any desired accuracy in a suitable limit. An 'intrinsic' time, based on the oscillator transition rate during tunnelling, transmission or reflection, is introduced. In simple situations the resulting intrinsic tunnelling time is shown to vanish to lowest order. In the general case a particular (nonzero) parametrisation is inferred, and its properties discussed in comparison with the literature on tunnelling times for both wavepackets and internal clocks. Copyright (1998) CSIRO Australia

Multiplying and detecting propagating microwave photons using inelastic Cooper-pair tunneling

Science.gov (United States)

Leppäkangas, Juha; Marthaler, Michael; Hazra, Dibyendu; Jebari, Salha; Albert, Romain; Blanchet, Florian; Johansson, Göran; Hofheinz, Max

2018-01-01

The interaction between propagating microwave fields and Cooper-pair tunneling across a DC-voltage-biased Josephson junction can be highly nonlinear. We show theoretically that this nonlinearity can be used to convert an incoming single microwave photon into an outgoing n -photon Fock state in a different mode. In this process, the electrostatic energy released in a Cooper-pair tunneling event is transferred to the outgoing Fock state, providing energy gain. The created multiphoton Fock state is frequency entangled and highly bunched. The conversion can be made reflectionless (impedance matched) so that all incoming photons are converted to n -photon states. With realistic parameters, multiplication ratios n >2 can be reached. By two consecutive multiplications, the outgoing Fock-state number can get sufficiently large to accurately discriminate it from vacuum with linear postamplification and power measurement. Therefore, this amplification scheme can be used as a single-photon detector without dead time.

Influence of quasiparticle multi-tunneling on the energy flow through the superconducting tunnel junction

International Nuclear Information System (INIS)

Samedov, V. V.; Tulinov, B. M.

2011-01-01

Superconducting tunnel junction (STJ) detector consists of two layers of superconducting material separated by thin insulating barrier. An incident particle produces in superconductor excess nonequilibrium quasiparticles. Each quasiparticle in superconductor should be considered as quantum superposition of electron-like and hole-like excitations. This duality nature of quasiparticle leads to the effect of multi-tunneling. Quasiparticle starts to tunnel back and forth through the insulating barrier. After tunneling from biased electrode quasiparticle loses its energy via phonon emission. Eventually, the energy that equals to the difference in quasiparticle energy between two electrodes is deposited in the signal electrode. Because of the process of multi-tunneling, one quasiparticle can deposit energy more than once. In this work, the theory of branching cascade processes was applied to the process of energy deposition caused by the quasiparticle multi-tunneling. The formulae for the mean value and variance of the energy transferred by one quasiparticle into heat were derived. (authors)

Enhanced MRI in carpal tunnel syndrome

International Nuclear Information System (INIS)

Hayakawa, Katsuhiko; Nakane, Takashi; Kobayashi, Shigeru; Asai, Takahiro; Wada, Kunio; Yoshizawa, Hidezo

1998-01-01

In this study, we performed contrast-enhanced MRI in patients with idiopathic carpal tunnel syndrome and examined the morphologic change in the carpal tunnel. In the transverse section of the opening of carpal tunnel where scaphoid and pisiform bones are figured out, we measured and examined 4 items, viz. the soft carpal tunnel volume, flat rate of median nerve, position of median nerve and thickness of palmer ligaments composing the base of carpal tunnel, with an image analyzer attached to the MRI apparatus. Whereas the average carpal tunnel volume in 12 hands of normal controls was 166.8 mm 2 , that in 74 hands of carpal tunnel syndrome was 207.2 mm 2 , a significant increase compared with the normal controls. The flat rate of median nerve was 46% in the controls, but that was 37.5% in the carpal tunnel syndrome, a significant flattening was noted. We connected the peaks of the scaphoid node and pisiform bone with a line and named it standard line. When we observed the position of median nerve in the carpal tunnel, the nerve in 9 of 12 hands, 75%, lay below the standard line in the controls, but the nerve in 65 of 74 hands, 87.8%, lay above the standard line in the carpal tunnel syndrome, clearly showing that the median nerve had shifted to the palmar side. Regarding these morphologic changes of the carpal tunnel, the internal pressure of the carpal tunnel is considered to be raised with swelling of the soft tissues mainly composing the inside of carpal tunnel, thus the area of cross section of carpal tunnel to be increased, the median nerve to be shifted to the palmar side and the median nerve to be compressed by the transverse carpal ligament at that time. Although we can observe these morphological changes readily in MRI images, these images show only the results of carpal tunnel syndrome after all, and do not specify the direct causes. However, we believe that these facts are important factors in the manifestation of idiopathic carpal tunnel syndrome. (author)

Josephson tunneling and nanosystems

OpenAIRE

Ovchinnikov, Yurii; Kresin, Vladimir

2010-01-01

Josephson tunneling between nanoclusters is analyzed. The discrete nature of the electronic energy spectra, including their shell ordering, is explicitly taken into account. The treatment considers the two distinct cases of resonant and non-resonant tunneling. It is demonstrated that the current density greatly exceeds the value discussed in the conventional theory. Nanoparticles are shown to be promising building blocks for nanomaterials-based tunneling networks.

Probing spin-polarized tunneling at high bias and temperature with a magnetic tunnel transistor

NARCIS (Netherlands)

Park, B.G.; Banerjee, T.; Min, B.C.; Sanderink, Johannes G.M.; Lodder, J.C.; Jansen, R.

2005-01-01

The magnetic tunnel transistor (MTT) is a three terminal hybrid device that consists of a tunnel emitter, a ferromagnetic (FM) base, and a semiconductor collector. In the MTT with a FM emitter and a single FM base, spin-polarized hot electrons are injected into the base by tunneling. After

Control of tunneling in heterostructures

International Nuclear Information System (INIS)

Volokhov, V M; Tovstun, C A; Ivlev, B

2007-01-01

A tunneling current between two rectangular potential wells can be effectively controlled by applying an external ac field. A variation of the ac frequency by 10% may lead to the suppression of the tunneling current by two orders of magnitude, which is a result of quantum interference under the action of the ac field. This effect of destruction of tunneling can be used as a sensitive control of tunneling current across nanosize heterostructures

Wind tunnel investigations on tritium reemission from soil

International Nuclear Information System (INIS)

Taeschner, M.; Bunnenberg, C.

1993-01-01

Future fusion plants and tritium handling facilities will contain large amounts of tritium. Following chronical or accidental releases to the atmosphere a secondary HTO source is established in the downwind sector of the tritium release point as a result of deposition processes. To investigate HTO reemission rates, experiments were performed with a special wind tunnel, in which the air flows across the surface of soil columns under controlled conditions. In order to measure the HTO content of an air sample that was experimentally contaminated by reemission of HTO from a labeled soil column, a fast method is used. The air sample is bubbled through a flask filled with a definite volume of low-tritium water. At the end of the sampling period, the volume and the specific activity of the flask water are measured. With the help of a simple mathematical formula, that is presented in this report, the HTO activity of the air sample can be calculated. (orig.) [de

Drilling the femoral tunnel during ACL reconstruction: transtibial versus anteromedial portal techniques.

Science.gov (United States)

Tudisco, Cosimo; Bisicchia, Salvatore

2012-08-01

Incorrect bone tunnel position, particularly on the femoral side, is a frequent cause of failed anterior cruciate ligament reconstruction. Several studies have reported that drilling the femoral tunnel through the anteromedial portal allows a more anatomical placement on the lateral femoral condyle and higher knee stability than does transtibial reconstruction.In the current study, the femoral tunnel was drilled with transtibial (n=6) and anteromedial (n=6) portal techniques in 12 cadaveric knees. With appropriate landmarks inserted into bone tunnels, the direction and length of the tunnels were determined on anteroposterior and lateral radiographs. Knee stability was evaluated with a KT1000 arthrometer (MEDmetric Corporation, San Diego, California) and pivot shift test, comparing the pre- and postoperative values of both techniques. Finally, all knees were dissected to enhance vision of the insertion of the reconstructed ligament. The anteromedial portal technique led to better placement of the femoral tunnel in the coronal and sagittal planes, with higher knee stability according to the pivot shift test but not the KT1000 arthrometer. Anatomical and clinical results reported in the literature on transtibial and anteromedial portal techniques are controversial, but most of studies report better results with the anteromedial portal technique, especially regarding rotational stability. The current cadaveric study showed that the anteromedial portal technique provided better tunnel placement on the lateral femoral condyle in the coronal and sagittal planes, with an improvement in the rotational stability of the knee. Copyright 2012, SLACK Incorporated.

Tunnelling in Soft Soil : Tunnel Boring Machine Operation and Soil Response

NARCIS (Netherlands)

Festa, D.; Broere, W.; Bosch, J.W.

2013-01-01

Constructing tunnels in soft soil with the use of Tunnel Boring Machines may induce settlements including soil movements ahead of the face, soil relaxation into the tail void, possible heave due to grouting, long lasting consolidation processes, and potentially several other mechanisms. A

Seismic prediction ahead of tunnel constructions

Science.gov (United States)

Jetschny, S.; Bohlen, T.; Nil, D. D.; Giese, R.

2007-12-01

To increase safety and efficiency of tunnel constructions, online seismic exploration ahead of a tunnel can become a valuable tool. Within the \\it OnSite project founded by the BMBF (German Ministry of Education and Research) within \\it GeoTechnologien a new forward looking seismic imaging technique is developed to e.g. determine weak and water bearing zones ahead of the constructions. Our approach is based on the excitation and registration of \\it tunnel surface waves. These waves are excited at the tunnel face behind the cutter head of a tunnel boring machine and travel into drilling direction. Arriving at the front face they generate body waves (mainly S-waves) propagating further ahead. Reflected S-waves are back- converted into tunnel surface waves. For a theoretical description of the conversion process and for finding optimal acquisition geometries it is of importance to study the propagation characteristics of tunnel surface waves. 3D seismic finite difference modeling and analytic solutions of the wave equation in cylindric coordinates revealed that at higher frequencies, i.e. if the tunnel diameter is significantly larger than the wavelength of S-waves, these surface waves can be regarded as Rayleigh-waves circulating the tunnel. For smaller frequencies, i.e. when the S-wavelength approaches the tunnel diameter, the propagation characteristics of these surface waves are then similar to S- waves. Field measurements performed by the GeoForschungsZentrum Potsdam, Germany at the Gotthard Base Tunnel (Switzerland) show both effects, i.e. the propagation of Rayleigh- and body-wave like waves along the tunnel. To enhance our understanding of the excitation and propagation characteristics of tunnel surface waves the transition of Rayleigh to tube-waves waves is investigated both analytically and by numerical simulations.

Carpal tunnel sonography by the rheumatologist versus nerve conduction study by the neurologist

NARCIS (Netherlands)

Swen, WAA; Jacobs, JWG; Bussemaker, FEAM; de Waard, J; Bijlsma, JWJ

Objective. To determine the value of sonogaphy (SG) performed by the rheumatologist to diagnose carpal tunnel syndrome (CTS). Methods. Sixty-three patients with clinical signs of CTS according to the neurologist. based on patient history and clinical examination, were studied. In the 6 weeks prior

Gap anisotropy and tunneling currents. [MPS3

DEFF Research Database (Denmark)

Lazarides, N.; Sørensen, Mads Peter

1996-01-01

The tunneling Hamiltonian formalism is applied to calculate the tunnelingcurrents through a small superconducting tunnel junction. The formalism isextended to nonconstant tunneling matrix elements. The electrodes of thejunction are assumed to......The tunneling Hamiltonian formalism is applied to calculate the tunnelingcurrents through a small superconducting tunnel junction. The formalism isextended to nonconstant tunneling matrix elements. The electrodes of thejunction are assumed to...

Blood Flow Changes in Subsynovial Connective Tissue on Contrast-Enhanced Ultrasonography in Patients With Carpal Tunnel Syndrome Before and After Surgical Decompression.

Science.gov (United States)

Motomiya, Makoto; Funakoshi, Tadanao; Ishizaka, Kinya; Nishida, Mutsumi; Matsui, Yuichiro; Iwasaki, Norimasa

2017-11-24

Although qualitative alteration of the subsynovial connective tissue in the carpal tunnel is considered to be one of the most important factors in the pathophysiologic mechanisms of carpal tunnel syndrome (CTS), little information is available about the microcirculation in the subsynovial connective tissue in patients with CTS. The aims of this study were to use contrast-enhanced ultrasonography (US) to evaluate blood flow in the subsynovial connective tissue proximal to the carpal tunnel in patients with CTS before and after carpal tunnel release. The study included 15 volunteers and 12 patients with CTS. The blood flow in the subsynovial connective tissue and the median nerve was evaluated preoperatively and at 1, 2, and 3 months postoperatively using contrast-enhanced US. The blood flow in the subsynovial connective tissue was higher in the patients with CTS than in the volunteers. In the patients with CTS, there was a significant correlation between the blood flow in the subsynovial connective tissue and the median nerve (P = .01). The blood flow in both the subsynovial connective tissue and the median nerve increased markedly after carpal tunnel release. Our results suggest that increased blood flow in the subsynovial connective tissue may play a role in the alteration of the microcirculation within the median nerve related to the pathophysiologic mechanisms of CTS. The increase in the blood flow in the subsynovial connective tissue during the early postoperative period may contribute to the changes in intraneural circulation, and these changes may lead to neural recovery. © 2017 by the American Institute of Ultrasound in Medicine.

Magnetic Fluxtube Tunneling

Science.gov (United States)

Dahlburg, Russell B.; Antiochos,, Spiro K.; Norton, D.

1996-01-01

We present numerical simulations of the collision and subsequent interaction of two initially orthogonal, twisted, force free field magnetic fluxtubes. The simulations were carried out using a new three dimensional explicit parallelized Fourier collocation algorithm for solving the viscoresistive equations of compressible magnetohydrodynamics. It is found that, under a wide range of conditions, the fluxtubes can 'tunnel' through each other. Two key conditions must be satisfied for tunneling to occur: the magnetic field must be highly twisted with a field line pitch much greater than 1, and the magnetic Lundquist number must be somewhat large, greater than or equal to 2880. This tunneling behavior has not been seen previously in studies of either vortex tube or magnetic fluxtube interactions. An examination of magnetic field lines shows that tunneling is due to a double reconnection mechanism. Initially orthogonal field lines reconnect at two specific locations, exchange interacting sections and 'pass' through each other. The implications of these results for solar and space plasmas are discussed.

Atomistic modeling trap-assisted tunneling in hole tunnel field effect transistors

Science.gov (United States)

Long, Pengyu; Huang, Jun Z.; Povolotskyi, Michael; Sarangapani, Prasad; Valencia-Zapata, Gustavo A.; Kubis, Tillmann; Rodwell, Mark J. W.; Klimeck, Gerhard

2018-05-01

Tunnel Field Effect Transistors (FETs) have the potential to achieve steep Subthreshold Swing (S.S.) below 60 mV/dec, but their S.S. could be limited by trap-assisted tunneling (TAT) due to interface traps. In this paper, the effect of trap energy and location on OFF-current (IOFF) of tunnel FETs is evaluated systematically using an atomistic trap level representation in a full quantum transport simulation. Trap energy levels close to band edges cause the highest leakage. Wave function penetration into the surrounding oxide increases the TAT current. To estimate the effects of multiple traps, we assume that the traps themselves do not interact with each other and as a whole do not modify the electrostatic potential dramatically. Within that model limitation, this numerical metrology study points to the critical importance of TAT in the IOFF in tunnel FETs. The model shows that for Dit higher than 1012/(cm2 eV) IO F F is critically increased with a degraded IO N/IO F F ratio of the tunnel FET. In order to have an IO N/IO F F ratio higher than 104, the acceptable Dit near Ev should be controlled to no larger than 1012/(cm2 eV) .

Lowest order in inelastic tunneling approximation : efficient scheme for simulation of inelastic electron tunneling data

NARCIS (Netherlands)

Rossen, E.T.R.; Flipse, C.F.J.; Cerda, J.I.

2013-01-01

We have developed an efficient and accurate formalism which allows the simulation at the ab initio level of inelastic electron tunneling spectroscopy data under a scanning tunneling microscope setup. It exploits fully the tunneling regime by carrying out the structural optimization and vibrational

How does tunneling contribute to counterintuitive H-abstraction reactivity of nonheme Fe(IV)O oxidants with alkanes?

Science.gov (United States)

Mandal, Debasish; Ramanan, Rajeev; Usharani, Dandamudi; Janardanan, Deepa; Wang, Binju; Shaik, Sason

2015-01-21

This article addresses the intriguing hydrogen-abstraction (H-abstraction) and oxygen-transfer (O-transfer) reactivity of a series of nonheme [Fe(IV)(O)(TMC)(Lax)](z+) complexes, with a tetramethyl cyclam ligand and a variable axial ligand (Lax), toward three substrates: 1,4-cyclohexadiene, 9,10-dihydroanthracene, and triphenyl phosphine. Experimentally, O-transfer-reactivity follows the relative electrophilicity of the complexes, whereas the corresponding H-abstraction-reactivity generally increases as the axial ligand becomes a better electron donor, hence exhibiting an antielectrophilic trend. Our theoretical results show that the antielectrophilic trend in H-abstraction is affected by tunneling contributions. Room-temperature tunneling increases with increase of the electron donation power of the axial-ligand, and this reverses the natural electrophilic trend, as revealed through calculations without tunneling, and leads to the observed antielectrophilic trend. By contrast, O-transfer-reactivity, not being subject to tunneling, retains an electrophilic-dependent reactivity trend, as revealed experimentally and computationally. Tunneling-corrected kinetic-isotope effect (KIE) calculations matched the experimental KIE values only if all of the H-abstraction reactions proceeded on the quintet state (S = 2) surface. As such, the present results corroborate the initially predicted two-state reactivity (TSR) scenario for these reactions. The increase of tunneling with the electron-releasing power of the axial ligand, and the reversal of the "natural" reactivity pattern, support the "tunneling control" hypothesis (Schreiner et al., ref 19). Should these predictions be corroborated, the entire field of C-H bond activation in bioinorganic chemistry would lay open to reinvestigation.

Scanning tunneling microscopic images and scanning tunneling spectra for coupled rectangular quantum corrals

International Nuclear Information System (INIS)

Mitsuoka, Shigenori; Tamura, Akira

2011-01-01

Assuming that an electron confined by double δ-function barriers lies in a quasi-stationary state, we derived eigenstates and eigenenergies of the electron. Such an electron has a complex eigenenergy, and the imaginary part naturally leads to the lifetime of the electron associated with tunneling through barriers. We applied this point of view to the electron confined in a rectangular quantum corral (QC) on a noble metal surface, and obtained scanning tunneling microscopic images and a scanning tunneling spectrum consistent with experimental ones. We investigated the electron states confined in coupled QCs and obtained the coupled states constructed with bonding and anti-bonding states. Using those energy levels and wavefunctions we specified scanning tunneling microscope (STM) images and scanning tunneling spectra (STS) for the doubly and triply coupled QCs. In addition we pointed out the feature of resonant electron states associated with the same QCs at both ends of the triply coupled QCs.

Automated identification of potential snow avalanche release areas based on digital elevation models

Directory of Open Access Journals (Sweden)

Y. Bühler

2013-05-01

Full Text Available The identification of snow avalanche release areas is a very difficult task. The release mechanism of snow avalanches depends on many different terrain, meteorological, snowpack and triggering parameters and their interactions, which are very difficult to assess. In many alpine regions such as the Indian Himalaya, nearly no information on avalanche release areas exists mainly due to the very rough and poorly accessible terrain, the vast size of the region and the lack of avalanche records. However avalanche release information is urgently required for numerical simulation of avalanche events to plan mitigation measures, for hazard mapping and to secure important roads. The Rohtang tunnel access road near Manali, Himachal Pradesh, India, is such an example. By far the most reliable way to identify avalanche release areas is using historic avalanche records and field investigations accomplished by avalanche experts in the formation zones. But both methods are not feasible for this area due to the rough terrain, its vast extent and lack of time. Therefore, we develop an operational, easy-to-use automated potential release area (PRA detection tool in Python/ArcGIS which uses high spatial resolution digital elevation models (DEMs and forest cover information derived from airborne remote sensing instruments as input. Such instruments can acquire spatially continuous data even over inaccessible terrain and cover large areas. We validate our tool using a database of historic avalanches acquired over 56 yr in the neighborhood of Davos, Switzerland, and apply this method for the avalanche tracks along the Rohtang tunnel access road. This tool, used by avalanche experts, delivers valuable input to identify focus areas for more-detailed investigations on avalanche release areas in remote regions such as the Indian Himalaya and is a precondition for large-scale avalanche hazard mapping.

Automated identification of potential snow avalanche release areas based on digital elevation models

Science.gov (United States)

Bühler, Y.; Kumar, S.; Veitinger, J.; Christen, M.; Stoffel, A.; Snehmani

2013-05-01

The identification of snow avalanche release areas is a very difficult task. The release mechanism of snow avalanches depends on many different terrain, meteorological, snowpack and triggering parameters and their interactions, which are very difficult to assess. In many alpine regions such as the Indian Himalaya, nearly no information on avalanche release areas exists mainly due to the very rough and poorly accessible terrain, the vast size of the region and the lack of avalanche records. However avalanche release information is urgently required for numerical simulation of avalanche events to plan mitigation measures, for hazard mapping and to secure important roads. The Rohtang tunnel access road near Manali, Himachal Pradesh, India, is such an example. By far the most reliable way to identify avalanche release areas is using historic avalanche records and field investigations accomplished by avalanche experts in the formation zones. But both methods are not feasible for this area due to the rough terrain, its vast extent and lack of time. Therefore, we develop an operational, easy-to-use automated potential release area (PRA) detection tool in Python/ArcGIS which uses high spatial resolution digital elevation models (DEMs) and forest cover information derived from airborne remote sensing instruments as input. Such instruments can acquire spatially continuous data even over inaccessible terrain and cover large areas. We validate our tool using a database of historic avalanches acquired over 56 yr in the neighborhood of Davos, Switzerland, and apply this method for the avalanche tracks along the Rohtang tunnel access road. This tool, used by avalanche experts, delivers valuable input to identify focus areas for more-detailed investigations on avalanche release areas in remote regions such as the Indian Himalaya and is a precondition for large-scale avalanche hazard mapping.

Ivar Giaever, Tunneling, and Superconductors

Science.gov (United States)

dropdown arrow Site Map A-Z Index Menu Synopsis Ivar Giaever, Tunneling, and Superconductors Resources with in Superconductors Measured by Electron Tunneling; Physical Review Letters, Vol. 5 Issue 4: 147 - 148 ; August 15, 1960 Electron Tunneling Between Two Superconductors; Physical Review Letters, Vol. 5 Issue 10

Physics of optimal resonant tunneling

NARCIS (Netherlands)

Racec, P.N.; Stoica, T.; Popescu, C.; Lepsa, M.I.; Roer, van de T.G.

1997-01-01

The optimal resonant tunneling, or the complete tunneling transparence of a biased double-barrier resonant-tunneling (DBRT) structure, is discussed. It is shown that its physics does not rest on the departure from the constant potential within the barriers and well, due to the applied electric

Spin-polarized tunneling with GaAs tips in scanning tunneling microscopy

NARCIS (Netherlands)

Prins, M.W.J.; Jansen, R.; Kempen, van H.

1996-01-01

We describe a model as well as experiments on spin-polarized tunneling with the aid of optical spin orientation. This involves tunnel junctions between a magnetic material and gallium arsenide (GaAs), where the latter is optically excited with circularly polarized light in order to generate

Ultrafast scanning tunneling microscopy

Energy Technology Data Exchange (ETDEWEB)

Botkin, D.A. [California Univ., Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley Lab., CA (United States)

1995-09-01

I have developed an ultrafast scanning tunneling microscope (USTM) based on uniting stroboscopic methods of ultrafast optics and scanned probe microscopy to obtain nanometer spatial resolution and sub-picosecond temporal resolution. USTM increases the achievable time resolution of a STM by more than 6 orders of magnitude; this should enable exploration of mesoscopic and nanometer size systems on time scales corresponding to the period or decay of fundamental excitations. USTM consists of a photoconductive switch with subpicosecond response time in series with the tip of a STM. An optical pulse from a modelocked laser activates the switch to create a gate for the tunneling current, while a second laser pulse on the sample initiates a dynamic process which affects the tunneling current. By sending a large sequence of identical pulse pairs and measuring the average tunnel current as a function of the relative time delay between the pulses in each pair, one can map the time evolution of the surface process. USTM was used to measure the broadband response of the STM`s atomic size tunnel barrier in frequencies from tens to hundreds of GHz. The USTM signal amplitude decays linearly with the tunnel junction conductance, so the spatial resolution of the time-resolved signal is comparable to that of a conventional STM. Geometrical capacitance of the junction does not appear to play an important role in the measurement, but a capacitive effect intimately related to tunneling contributes to the measured signals and may limit the ultimate resolution of the USTM.

13th Australian tunnelling conference. Proceedings

Energy Technology Data Exchange (ETDEWEB)

NONE

2008-07-01

The theme of the conference was 'Engineering in a changing environment'. Topics covered include Australian tunnelling projects, design and development of ground support, tunnelling, international projects, fire and life safety, mining projects, risk management in tunnelling, and tunnel boring machine tunnelling. Papers of particular interest to the coal industry are: improving roadway development in underground coal mine (G. Lewis and G. Gibson), and polymer-based alternative to steel mesh for coal mine strata reinforcement (C. Lukey and others).

The potential complications of open carpal tunnel release surgery to the ulnar neurovascular bundle and its branches: A cadaveric study.

Science.gov (United States)

Boughton, O; Adds, P J; Jayasinghe, J A P

2010-07-01

This study investigated the ulnar artery and the ulnar nerve and its branches in the palm to assess how frequently they may be at risk of damage during open carpal tunnel release surgery. Twenty-one formalin-embalmed cadaveric hands were dissected, and the proximity of the ulnar neurovascular bundle to two different lines of incision, the 3rd and 4th interdigital web space axis and the ring finger axis, was assessed and compared. It was found that an incision in the latter (ring finger) axis put the ulnar artery at risk in 12 of 21 specimens, whereas an incision in the former axis (3rd/4th interdigital web space) put the ulnar artery at risk in only two specimens. In 15 hands at least one structure (the ulnar artery or a branch of the ulnar nerve) was at risk in the ring finger axis compared to only seven hands in the axis of the 3rd/4th interdigital web space. We conclude that the ulnar artery and branches of the ulnar nerve are at increased risk of damage with an incision in the axis of the ring finger. The importance of using a blunt dissection technique under direct vision during surgery to identify and preserve these structures and median nerve branches is emphasized. (c) 2010 Wiley-Liss, Inc.

Derivation of the tunnelling exchange time for the model of trap-assisted tunnelling

International Nuclear Information System (INIS)

Racko, J.; Ballo, P.; Benko, P.; Harmatha, L.; Grmanova, A.; Breza, J.

2014-01-01

We present derivation of the tunnelling exchange times that play the key role in the model of trap assisted tunnelling (TAT) considering the electron and hole exchange processes between the trapping centre lying in the forbidden band of the semiconductor and the conduction band, valence band or a metal. All exchange processes are quantitatively described by respective exchange times. The reciprocal values of these exchange times represent the frequency with which the exchange processes contribute to the probability of occupation of the trap by free charge carriers. The crucial problem in any model of TAT is the calculation of the occupation probability. In our approach this probability is expressed in terms of only thermal and tunnelling exchange times. The concept of tunnelling exchange times presents a dominant contribution to our model of TAT. The new approach allows to simply calculate the probability of occupation of the trapping centre by a free charge carrier and subsequently to get the thermal and tunnelling generation-recombination rates occurring in the continuity equations. This is why the TAT model based on thermal and tunnelling exchange times is suitable for simulating the electrical properties of semiconductor nanostructures in which quantum mechanical phenomena play a key role. (authors)

Electronic noise of superconducting tunnel junction detectors

International Nuclear Information System (INIS)

Jochum, J.; Kraus, H.; Gutsche, M.; Kemmather, B.; Feilitzsch, F. v.; Moessbauer, R.L.

1994-01-01

The optimal signal to noise ratio for detectors based on superconducting tunnel junctions is calculated and compared for the cases of a detector consisting of one single tunnel junction, as well as of series and of parallel connections of such tunnel junctions. The influence of 1 / f noise and its dependence on the dynamical resistance of tunnel junctions is discussed quantitatively. A single tunnel junction yields the minimum equivalent noise charge. Such a tunnel junction exhibits the best signal to noise ratio if the signal charge is independent of detector size. In case, signal charge increases with detector size, a parallel or a series connection of tunnel junctions would provide the optimum signal to noise ratio. The equivalent noise charge and the respective signal to noise ratio are deduced as functions of tunnel junction parameters such as tunneling time, quasiparticle lifetime, etc. (orig.)

Tunneling of Atoms, Nuclei and Molecules

International Nuclear Information System (INIS)

Bertulani, C.A.

2015-01-01

This is a brief review of few relevant topics on tunneling of composite particles and how the coupling to intrinsic and external degrees of freedom affects tunneling probabilities. I discuss the phenomena of resonant tunneling, different barriers seen by subsystems, damping of resonant tunneling by level bunching and continuum effects due to particle dissociation. (author)

Underground Nuclear Explosions and Release of Radioactive Noble Gases

Science.gov (United States)

Dubasov, Yuri V.

2010-05-01

Over a period in 1961-1990 496 underground nuclear tests and explosions of different purpose and in different rocks were conducted in the Soviet Union at Semipalatinsk and anovaya Zemlya Test Sites. A total of 340 underground nuclear tests were conducted at the Semipalatinsk Test Site. One hundred seventy-nine explosions (52.6%) among them were classified as these of complete containment, 145 explosions (42.6%) as explosions with weak release of radioactive noble gases (RNG), 12 explosions (3.5%) as explosions with nonstandard radiation situation, and four excavation explosions with ground ejection (1.1%). Thirty-nine nuclear tests had been conducted at the Novaya Zemlya Test Site; six of them - in shafts. In 14 tests (36%) there were no RNG release. Twenty-three tests have been accompanied by RNG release into the atmosphere without sedimental contamination. Nonstandard radiation situation occurred in two tests. In incomplete containment explosions both early-time RNG release (up to ~1 h) and late-time release from 1 to 28 h after the explosion were observed. Sometimes gas release took place for several days, and it occurred either through tunnel portal or epicentral zone, depending on atmospheric air temperature.

Chaos regularization of quantum tunneling rates

International Nuclear Information System (INIS)

Pecora, Louis M.; Wu Dongho; Lee, Hoshik; Antonsen, Thomas; Lee, Ming-Jer; Ott, Edward

2011-01-01

Quantum tunneling rates through a barrier separating two-dimensional, symmetric, double-well potentials are shown to depend on the classical dynamics of the billiard trajectories in each well and, hence, on the shape of the wells. For shapes that lead to regular (integrable) classical dynamics the tunneling rates fluctuate greatly with eigenenergies of the states sometimes by over two orders of magnitude. Contrarily, shapes that lead to completely chaotic trajectories lead to tunneling rates whose fluctuations are greatly reduced, a phenomenon we call regularization of tunneling rates. We show that a random-plane-wave theory of tunneling accounts for the mean tunneling rates and the small fluctuation variances for the chaotic systems.

Excavation of the Surikamigawa dam diversion tunnel. Surikamigawa dam karihaisui tunnel kantsu

Energy Technology Data Exchange (ETDEWEB)

Ikeda, T.; Konno, T. (Ministry of Construction, Tokyo (Japan))

1994-04-01

A bypass tunnel construction has been completed at the Surikamigawa dam (Japan). This paper describes the summary of the construction. The full-swing dam construction work is scheduled to begin in 1995. The soils distributed near the dam site consist of lapillus tuff containing andesite-based light stones and tuff-based conglomerates containing large gravels. Excavation of the dam diversion tunnel has used a blasting method, and the tunnel construction has adopted an automatic tunnel cross section marking system and a non-electric explosion method. This marking system is a system to irradiate a laser beam onto the facing to depict excavation lines that realizes labor saving and high-accuracy excavation. The error at the tunnel completion was found 20 mm. The non-electric explosion method ignites a coated explosive layer with an impact wave, which is electrostatically safe, and reduces blasting vibration. Electric detonators have also been used because of using ANFO explosives. The result obtained from measurements of inner space displacement necessary for the blasting process has indicated that the area near the dam site consists of stable mountains. 6 figs., 4 tabs.

Charge Islands Through Tunneling

Science.gov (United States)

Robinson, Daryl C.

2002-01-01

It has been recently reported that the electrical charge in a semiconductive carbon nanotube is not evenly distributed, but rather it is divided into charge "islands." This paper links the aforementioned phenomenon to tunneling and provides further insight into the higher rate of tunneling processes, which makes tunneling devices attractive. This paper also provides a basis for calculating the charge profile over the length of the tube so that nanoscale devices' conductive properties may be fully exploited.

Tunneling progress on the Yucca Mountain Project

International Nuclear Information System (INIS)

Hansmire, W.H.; Munzer, R.J.

1996-01-01

The current status of tunneling progress on the Yucca Mountain Project (YMP) is presented in this paper. The Exploratory Studies Facility (ESF), a key part of the YMP, has been long in development and construction is ongoing. This is a progress report on the tunneling aspects of the ESF as of January 1, 1996. For purposes of discussion in this summary, the tunneling has progressed in four general phases. The paper describes: tunneling in jointed rock under low stress; tunneling through the Bow Ridge Fault and soft rock; tunneling through the Imbricate Fault Zone; and Tunneling into the candidate repository formation

Peak stresses shift from femoral tunnel aperture to tibial tunnel aperture in lateral tibial tunnel ACL reconstructions: a 3D graft-bending angle measurement and finite-element analysis.

Science.gov (United States)

Van Der Bracht, Hans; Tampere, Thomas; Beekman, Pieter; Schepens, Alexander; Devriendt, Wouter; Verdonk, Peter; Victor, Jan

2018-02-01

To investigate the effect of tibial tunnel orientation on graft-bending angle and stress distribution in the ACL graft. Eight cadaveric knees were scanned in extension, 45°, 90°, and full flexion. 3D reconstructions with anatomically placed anterior cruciate ligament (ACL) grafts were constructed with Mimics 14.12 ® . 3D graft-bending angles were measured for classic medial tibial tunnels (MTT) and lateral tibial tunnels (LTT) with different drill-guide angles (DGA) (45°, 55°, 65°, and 75°). A pivot shift was performed on 1 knee in a finite-element analysis. The peak stresses in the graft were calculated for eight different tibial tunnel orientations. In a classic anatomical ACL repair, the largest graft-bending angle and peak stresses are seen at the femoral tunnel aperture. The use of a different DGA at the tibial side does not change the graft-bending angle at the femoral side or magnitude of peak stresses significantly. When using LTT, the largest graft-bending angles and peak stresses are seen at the tibial tunnel aperture. In a classic anatomical ACL repair, peak stresses in the ACL graft are found at the femoral tunnel aperture. When an LTT is used, peak stresses are similar compared to classic ACL repairs, but the location of the peak stress will shift from the femoral tunnel aperture towards the tibial tunnel aperture. the risk of graft rupture is similar for both MTTs and LTTs, but the location of graft rupture changes from the femoral tunnel aperture towards the tibial tunnel aperture, respectively. I.

Hypersonic Tunnel Facility (HTF)

Data.gov (United States)

Federal Laboratory Consortium — The Hypersonic Tunnel Facility (HTF) is a blow-down, non-vitiated (clean air) free-jet wind tunnel capable of testing large-scale, propulsion systems at Mach 5, 6,...

Klein tunneling phenomenon with pair creation process

Science.gov (United States)

Wu, G. Z.; Zhou, C. T.; Fu, L. B.

2018-01-01

In this paper, we study the Klein tunneling phenomenon with electron-positron pair creation process. Pairs can be created from the vacuum by a supercritical single-well potential (for electrons). In the time region, the time-dependent growth pattern of the created pairs can be characterized by four distinct regimes which can be considered as four different statuses of the single well. We find that if positrons penetrate the single well by Klein tunneling in different statuses, the total number of the tunneling positrons will be different. If Klein tunneling begins at the initial stage of the first status i.e. when the sing well is empty, the tunneling process and the total number of tunneling positrons are similar to the traditional Klein tunneling case without considering the pair creation process. As the tunneling begins later, the total tunneling positron number increases. The number will finally settle to an asymptotic value when the tunneling begins later than the settling-down time t s of the single well which has been defined in this paper.

Specific features of the behaviour of excess currents in tunnel diodes of n-GaAs

International Nuclear Information System (INIS)

Vyatkin, A.P.; Glushchenko, V.A.; Parkhomenko, R.P.; Pastor, A.P.

1981-01-01

The behaviour of currents in the field of a valley of volt-ampere characteristics (VAC) and the effect of 2.0 MeV electron bombardment on the characteristics of tunnel n-GaAs of TD diodes is considered. Release of tunnel and thermal current components has shown that the first component of excess currents is due to electron tunneling through intermediate states situated in a wide region of the forbidden zone. The nature of the second current component is explained by far reaching into the region of the forbidden zone tails of electron states on which energy impurity states can superimpose. Highly-alloyed TD with concentrations n>=3x10 19 cm -3 and p=(1.5-2)x10 20 cm -3 practically are not sensitive to doses up to phi approximately 2x10 17 el/cm 2 . Radiation induced defects related with electron bombardment is rather small. Specific features of the preparation of n-GaAs tunnel diodes lead to the fact that as a result of complex alloying of the p-region of the diode a relatively slow increase of excess currents as compared with the TD corresponding currents from the p-GaAs is observed

Tunneling time, what is its meaning?

International Nuclear Information System (INIS)

McDonald, C R; Orlando, G; Vampa, G; Brabec, T

2015-01-01

The tunnel time ionization dynamics for bound systems in laser fields are investigated. Numerical analysis for a step function switch-on of the field allows for the tunnel time to be defined as the time it takes the ground state to develop the under-barrier wavefunction components necessary to achieve the static field ionization rate. A relation between the tunnel time and the Keldysh time is established. The definition of the tunnel time is extended to time varying fields and experimental possibilities for measuring the tunnel time are discussed

Transonic Dynamics Tunnel (TDT)

Data.gov (United States)

Federal Laboratory Consortium — The Transonic Dynamics Tunnel (TDT) is a continuous flow wind-tunnel facility capable of speeds up to Mach 1.2 at stagnation pressures up to one atmosphere. The TDT...

Effects of neglecting carrier tunneling on electrostatic potential in calculating direct tunneling gate current in deep submicron MOSFETs

OpenAIRE

Hakim, MMA; Haque, A

2002-01-01

We investigate the validity of the assumption of neglecting carrier tunneling effects on self-consistent electrostatic potential in calculating direct tunneling gate current in deep submicron MOSFETs. Comparison between simulated and experimental results shows that for accurate modeling of direct tunneling current, tunneling effects on potential profile need to be considered. The relative error in gate current due to neglecting carrier tunneling is higher at higher gate voltages and increases...

Road and Railroad Tunnels

Data.gov (United States)

Department of Homeland Security — Tunnels in the United States According to the HSIP Tiger Team Report, a tunnel is defined as a linear underground passageway open at both ends. This dataset is based...

PUREX Storage Tunnels dangerous waste permit application

International Nuclear Information System (INIS)

1991-12-01

The PUREX Storage Tunnels are a mixed waste storage unit consisting of two underground railroad tunnels: Tunnel Number 1 designated 218-E-14 and Tunnel Number 2 designated 218-E-15. The two tunnels are connected by rail to the PUREX Plant and combine to provide storage space for 48 railroad cars (railcars). The PUREX Storage Tunnels provide a long-term storage location for equipment removed from the PUREX Plant. Transfers into the PUREX Storage Tunnels are made on an as-needed basis. Radioactively contaminated equipment is loaded on railcars and remotely transferred by rail into the PUREX Storage Tunnels. Railcars act as both a transport means and a storage platform for equipment placed into the tunnels. This report consists of part A and part B. Part A reports on amounts and locations of the mixed water. Part B permit application consists of the following: Facility Description and General Provisions; Waste Characteristics; Process Information; Groundwater Monitoring; Procedures to Prevent Hazards; Contingency Plan; Personnel Training; Exposure Information Report

Electrically tunable tunneling rectification magnetoresistance in magnetic tunneling junctions with asymmetric barriers.

Science.gov (United States)

Wang, Jing; Huang, Qikun; Shi, Peng; Zhang, Kun; Tian, Yufeng; Yan, Shishen; Chen, Yanxue; Liu, Guolei; Kang, Shishou; Mei, Liangmo

2017-10-26

The development of multifunctional spintronic devices requires simultaneous control of multiple degrees of freedom of electrons, such as charge, spin and orbit, and especially a new physical functionality can be realized by combining two or more different physical mechanisms in one specific device. Here, we report the realization of novel tunneling rectification magnetoresistance (TRMR), where the charge-related rectification and spin-dependent tunneling magnetoresistance are integrated in Co/CoO-ZnO/Co magnetic tunneling junctions with asymmetric tunneling barriers. Moreover, by simultaneously applying direct current and alternating current to the devices, the TRMR has been remarkably tuned in the range from -300% to 2200% at low temperature. This proof-of-concept investigation provides an unexplored avenue towards electrical and magnetic control of charge and spin, which may apply to other heterojunctions to give rise to more fascinating emergent functionalities for future spintronics applications.

Scanning tunneling microscopy

International Nuclear Information System (INIS)

Binnig, G.; Rohrer, H.

1983-01-01

Based on vacuum tunneling, a novel type of microscope, the scanning tunneling microscope (STM) was developed. It has an unprecedented resolution in real space on an atomic scale. The authors review the important technical features, illustrate the power of the STM for surface topographies and discuss its potential in other areas of science and technology. (Auth.)

Scanning tunneling microscope nanoetching method

Science.gov (United States)

Li, Yun-Zhong; Reifenberger, Ronald G.; Andres, Ronald P.

1990-01-01

A method is described for forming uniform nanometer sized depressions on the surface of a conducting substrate. A tunneling tip is used to apply tunneling current density sufficient to vaporize a localized area of the substrate surface. The resulting depressions or craters in the substrate surface can be formed in information encoding patterns readable with a scanning tunneling microscope.

Superconducting tunneling with the tunneling Hamiltonian. II. Subgap harmonic structure

International Nuclear Information System (INIS)

Arnold, G.B.

1987-01-01

The theory of superconducting tunneling without the tunneling Hamiltonian is extended to treat superconductor/insulator/superconductor junctions in which the transmission coefficient of the insulating barrier approaches unity. The solution for the current in such junctions is obtained by solving the problem of a particle hopping in a one-dimensional lattice of sites, with forward and reverse transfer integrals that depend on the site. The results are applied to the problem of subgap harmonic structure in superconducting tunneling. The time-dependent current at finite voltage through a junction exhibiting subgap structure is found to have terms that oscillate at all integer multiples of the Josephson frequency, n(2eV/h). The amplitudes of these new, and as yet unmeasured, ac current contributions as a function of voltage are predicted

Replacing carbamazepine slow-release tablets with carbamazepine suppositories: a pharmacokinetic and clinical study in children with epilepsy.

Science.gov (United States)

Arvidsson, J; Nilsson, H L; Sandstedt, P; Steinwall, G; Tonnby, B; Flesch, G

1995-03-01

A suppository for rectal administration of carbamazepine has been developed for situations in which it is unsuitable to use the oral route of administration. In an open, controlled, within-patient study, the pharmacokinetics, clinical efficacy, and tolerability of carbamazepine slow-release tablets were compared with those of carbamazepine suppositories in children with epilepsy. The pharmacokinetic part of the study comprised 22 children, and an additional nine children were included in the clinical part of the study. Treatment with slow-release tablets was replaced for 7 days with carbamazepine suppositories in bioequivalent dosage. Clinical factors such as the rate of seizures and the local tolerability were studied, and an overall assessment of efficacy was made. In the pharmacokinetic part, 24-hour plasma concentration curves for carbamazepine and carbamazepine-10,11-epoxide were recorded. The plasma concentration profiles (minimum, maximum, and mean concentrations, fluctuation index, and area under the curve) for carbamazepine and the other metabolites did not show any significant differences between oral and rectal administration when the suppository dose was increased by 25% compared to the tablets. No increase in seizure frequency was detected, and the overall assessment was very good to good in 25 of the 29 epileptic children. Increased flatulence during treatment with suppositories was noted in two children, one had anal irritation, and one had nausea/vomiting. Treatment with carbamazepine slow-release tablets in children with epilepsy can be replaced by carbamazepine suppositories in 25% higher dosage, with good clinical effect and appropriate pharmacokinetic values, when it is unsuitable to use the common oral route of administration.

Dirac particle tunneling from black rings

International Nuclear Information System (INIS)

Jiang Qingquan

2008-01-01

Recent research shows that Hawking radiation can be treated as a quantum tunneling process, and Hawking temperatures of Dirac particles across the horizon of a black hole can be correctly recovered via the fermion tunneling method. In this paper, motivated by the fermion tunneling method, we attempt to apply the analysis to derive Hawking radiation of Dirac particles via tunneling from black ring solutions of 5-dimensional Einstein-Maxwell-dilaton gravity theory. Finally, it is interesting to find that, as in the black hole case, fermion tunneling can also result in correct Hawking temperatures for the rotating neutral, dipole, and charged black rings.

Engineers win award for Swiss tunnel

CERN Multimedia

2003-01-01

A Derby engineering consultancy has won the Tunnelling Industry Award 2003 for Excellence in Tunnel Design, offered by the British Tunnelling Society, for its work on the LHC in Geneva, Switzerland (1/2 page).

Semiclassical description of resonant tunneling

International Nuclear Information System (INIS)

Bogomolny, E.B.; Rouben, D.C.

1996-01-01

A semiclassical formula is calculated for the tunneling current of electrons trapped in a potential well which can tunnel into and across a wide quantum well. The tunneling current is measured at the second interface of this well and the calculations idealized an experimental situation where a strong magnetic field tilted with respect to an electric field was used. It is shown that the contribution to the tunneling current, due to trajectories which begin at the first interface and end on the second, is dominant for periodic orbits which hit both walls of the quantum well. (author)

Clinical applications of the sustained-release dexamethasone implant for treatment of macular edema

Directory of Open Access Journals (Sweden)

Rocío Herrero-Vanrell, Jose Augusto Cardillo

2011-02-01

Full Text Available Rocío Herrero-Vanrell1, Jose Augusto Cardillo2, Baruch D Kuppermann31Department of Pharmacy and Pharmaceutical Technology, School of Pharmacy, Complutense University, Madrid, Spain; 2Hospital de Olhos de Araraquara, Araraquara, São Paulo, Brazil; 3Gavin Herbert Eye Institute, University of California, Irvine, CA, USAAbstract: Macular edema is one of the leading causes of vision loss among patients with retinal vein occlusion, diabetic retinopathy, and posterior chamber inflammatory disease. However, the treatment of macular edema is considerably limited by the difficulty in delivering effective doses of therapeutic agents into the vitreous cavity. In recent years, the development of a sustained-release dexamethasone intravitreal implant (Ozurdex® has enabled more controlled drug release at a stable rate over a long period of time, with a potentially lower rate of adverse events. Clinical studies indicate that this dexamethasone implant is a promising new treatment option for patients with persistent macular edema resulting from retinal vein occlusion, diabetic retinopathy, and uveitis or Irvine-Gass syndrome.Keywords: diabetic retinopathy, macular edema, Ozurdex®, posterior-segment inflammatory disease, retinal vein occlusion, sustained-release dexamethasone implant

Tunneling Ionization of Diatomic Molecules

DEFF Research Database (Denmark)

Svensmark, Jens Søren Sieg

2016-01-01

When a molecule is subject to a strong laser field, there is a probability that an electron can escape, even though the electrons are bound by a large potential barrier. This is possible because electrons are quantum mechanical in nature, and they are therefore able to tunnel through potential...... barriers, an ability classical particles do not possess. Tunnelling is a fundamental quantum mechanical process, a process that is distinctly non-classical, so solving this tunnelling problem is not only relevant for molecular physics, but also for quantum theory in general. In this dissertation the theory...... of tunneling ionizaion of molecules is presented and the results of numerical calculations are shown. One perhaps surprising result is, that the frequently used Born-Oppenheimer approximation breaks down for weak fields when describing tunneling ionization. An analytic theory applicable in the weak-field limit...

Asymmetric voltage behavior of the tunnel magnetoresistance in double barrier magnetic tunnel junctions

KAUST Repository

Useinov, Arthur

2012-06-01

In this paper, we study the value of the tunnel magnetoresistance (TMR) as a function of the applied voltage in double barrier magnetic tunnel junctions (DMTJs) with the left and right ferromagnetic (FM) layers being pinned and numerically estimate the possible difference of the TMR curves for negative and positive voltages in the homojunctions (equal barriers and electrodes). DMTJs are modeled as two single barrier junctions connected in series with consecutive tunneling (CST). We investigated the asymmetric voltage behavior of the TMR for the CST in the range of a general theoretical model. Significant asymmetries of the experimental curves, which arise due to different annealing regimes, are mostly explained by different heights of the tunnel barriers and asymmetries of spin polarizations in magnetic layers. © (2012) Trans Tech Publications.

Asymmetric voltage behavior of the tunnel magnetoresistance in double barrier magnetic tunnel junctions

KAUST Repository

Useinov, Arthur; Gooneratne, Chinthaka Pasan; Kosel, Jü rgen

2012-01-01

In this paper, we study the value of the tunnel magnetoresistance (TMR) as a function of the applied voltage in double barrier magnetic tunnel junctions (DMTJs) with the left and right ferromagnetic (FM) layers being pinned and numerically estimate the possible difference of the TMR curves for negative and positive voltages in the homojunctions (equal barriers and electrodes). DMTJs are modeled as two single barrier junctions connected in series with consecutive tunneling (CST). We investigated the asymmetric voltage behavior of the TMR for the CST in the range of a general theoretical model. Significant asymmetries of the experimental curves, which arise due to different annealing regimes, are mostly explained by different heights of the tunnel barriers and asymmetries of spin polarizations in magnetic layers. © (2012) Trans Tech Publications.

Insertion of the Biogenesis Factor Rei1 Probes the Ribosomal Tunnel during 60S Maturation.

Science.gov (United States)

Greber, Basil Johannes; Gerhardy, Stefan; Leitner, Alexander; Leibundgut, Marc; Salem, Michèle; Boehringer, Daniel; Leulliot, Nicolas; Aebersold, Ruedi; Panse, Vikram Govind; Ban, Nenad

2016-01-14

Eukaryotic ribosome biogenesis depends on several hundred assembly factors to produce functional 40S and 60S ribosomal subunits. The final phase of 60S subunit biogenesis is cytoplasmic maturation, which includes the proofreading of functional centers of the 60S subunit and the release of several ribosome biogenesis factors. We report the cryo-electron microscopy (cryo-EM) structure of the yeast 60S subunit in complex with the biogenesis factors Rei1, Arx1, and Alb1 at 3.4 Å resolution. In addition to the network of interactions formed by Alb1, the structure reveals a mechanism for ensuring the integrity of the ribosomal polypeptide exit tunnel. Arx1 probes the entire set of inner-ring proteins surrounding the tunnel exit, and the C terminus of Rei1 is deeply inserted into the ribosomal tunnel, where it forms specific contacts along almost its entire length. We provide genetic and biochemical evidence that failure to insert the C terminus of Rei1 precludes subsequent steps of 60S maturation. Copyright © 2016 Elsevier Inc. All rights reserved.

A normal metal tunnel-junction heat diode

Energy Technology Data Exchange (ETDEWEB)

Fornieri, Antonio, E-mail: antonio.fornieri@sns.it; Martínez-Pérez, María José; Giazotto, Francesco, E-mail: giazotto@sns.it [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa (Italy)

2014-05-05

We propose a low-temperature thermal rectifier consisting of a chain of three tunnel-coupled normal metal electrodes. We show that a large heat rectification is achievable if the thermal symmetry of the structure is broken and the central island can release energy to the phonon bath. The performance of the device is theoretically analyzed and, under the appropriate conditions, temperature differences up to ∼200 mK between the forward and reverse thermal bias configurations are obtained below 1 K, corresponding to a rectification ratio R∼2000. The simplicity intrinsic to its design joined with the insensitivity to magnetic fields make our device potentially attractive as a fundamental building block in solid-state thermal nanocircuits and in general-purpose cryogenic electronic applications requiring energy management.

Trigger wrist and carpal tunnel syndrome caused by hand intramuscular intrasynovial angiofibrolipoma: A rare case report

Directory of Open Access Journals (Sweden)

Turan C Dulgeroglu

2016-08-01

Full Text Available Trigger wrist is a clinical entity characterized by triggering or the crackling of the wrist. Here, a case is reported of intrasynovial angiofibrolipoma that caused trigger wrist and carpal tunnel syndrome. This is the only case report where trigger wrist and carpal tunnel syndrome caused by the intrasynovial angiofibrolipoma were developed simultaneously. it is believed that that adhesive tenosynovitis developing in the tendons may have contributed to the triggering and carpal tunnel syndrome in the wrist as a result of inflammation occuring as a consequence of intrasynovial angiofibrolipoma. [Hand Microsurg 2016; 5(2.000: 107-109

Spent fuel transportation cask response to a tunnel fire scenario

Energy Technology Data Exchange (ETDEWEB)

Bajwa, C.S. [U.S. Nuclear Regulatory Commission, Washington, D.C. (United States); Adkins, H.E.; Cuta, J.M. [Pacific Northwest National Lab., Richland, WA (United States)

2004-07-01

On July 18, 2001, a freight train carrying hazardous (non-nuclear) materials derailed and caught fire while passing through the Howard Street railroad tunnel in downtown Baltimore, Maryland. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook an investigation of the train derailment and fire to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by railroad. Shortly after the accident occurred, the USNRC met with the National Transportation Safety Board (NTSB), the U.S. agency responsible for determining the cause of transportation accidents, to discuss the details of the accident and the ensuing fire. Following these discussions, the USNRC assembled a team of experts from the National Institute of Standards and Technology (NIST), the Center for Nuclear Waste Regulatory Analyses (CNWRA), and Pacific Northwest National Laboratory (PNNL) to determine the thermal conditions that existed in the Howard Street tunnel fire and analyze the effects of this fire on various spent fuel transportation cask designs. The Fire Dynamics Simulator (FDS) code, developed by NIST, was used to determine the thermal environment present in the Howard Street tunnel during the fire. The FDS results were used as boundary conditions in the ANSYS {sup registered} and COBRA-SFS computer codes to evaluate the thermal performance of different cask designs. The staff concluded that the transportation casks analyzed would withstand a fire with thermal conditions similar to those that existed in the Baltimore tunnel fire event. No release of radioactive materials would result from exposure of the casks analyzed to such an event. This paper describes the methods and approach used for this assessment.

Spent fuel transportation cask response to a tunnel fire scenario

International Nuclear Information System (INIS)

Bajwa, C.S.; Adkins, H.E.; Cuta, J.M.

2004-01-01

On July 18, 2001, a freight train carrying hazardous (non-nuclear) materials derailed and caught fire while passing through the Howard Street railroad tunnel in downtown Baltimore, Maryland. The United States Nuclear Regulatory Commission (USNRC), one of the agencies responsible for ensuring the safe transportation of radioactive materials in the United States, undertook an investigation of the train derailment and fire to determine the possible regulatory implications of this particular event for the transportation of spent nuclear fuel by railroad. Shortly after the accident occurred, the USNRC met with the National Transportation Safety Board (NTSB), the U.S. agency responsible for determining the cause of transportation accidents, to discuss the details of the accident and the ensuing fire. Following these discussions, the USNRC assembled a team of experts from the National Institute of Standards and Technology (NIST), the Center for Nuclear Waste Regulatory Analyses (CNWRA), and Pacific Northwest National Laboratory (PNNL) to determine the thermal conditions that existed in the Howard Street tunnel fire and analyze the effects of this fire on various spent fuel transportation cask designs. The Fire Dynamics Simulator (FDS) code, developed by NIST, was used to determine the thermal environment present in the Howard Street tunnel during the fire. The FDS results were used as boundary conditions in the ANSYS registered and COBRA-SFS computer codes to evaluate the thermal performance of different cask designs. The staff concluded that the transportation casks analyzed would withstand a fire with thermal conditions similar to those that existed in the Baltimore tunnel fire event. No release of radioactive materials would result from exposure of the casks analyzed to such an event. This paper describes the methods and approach used for this assessment

Quantum tunneling with friction

Science.gov (United States)

Tokieda, M.; Hagino, K.

2017-05-01

Using the phenomenological quantum friction models introduced by P. Caldirola [Nuovo Cimento 18, 393 (1941), 10.1007/BF02960144] and E. Kanai [Prog. Theor. Phys. 3, 440 (1948), 10.1143/ptp/3.4.440], M. D. Kostin [J. Chem. Phys. 57, 3589 (1972), 10.1063/1.1678812], and K. Albrecht [Phys. Lett. B 56, 127 (1975), 10.1016/0370-2693(75)90283-X], we study quantum tunneling of a one-dimensional potential in the presence of energy dissipation. To this end, we calculate the tunneling probability using a time-dependent wave-packet method. The friction reduces the tunneling probability. We show that the three models provide similar penetrabilities to each other, among which the Caldirola-Kanai model requires the least numerical effort. We also discuss the effect of energy dissipation on quantum tunneling in terms of barrier distributions.

INCAS TRISONIC WIND TUNNEL

Directory of Open Access Journals (Sweden)

Florin MUNTEANU

2009-09-01

Full Text Available The 1.2 m x 1.2 m Trisonic Blowdown Wind Tunnel is the largest of the experimental facilities at the National Institute for Aerospace Research - I.N.C.A.S. "Elie Carafoli", Bucharest, Romania. The tunnel has been designed by the Canadian company DSMA (now AIOLOS and since its commissioning in 1978 has performed high speed aerodynamic tests for more than 120 projects of aircraft, missiles and other objects among which the twin jet fighter IAR-93, the jet trainer IAR-99, the MIG-21 Lancer, the Polish jet fighter YRYDA and others. In the last years the wind tunnel has been used mostly for experimental research in European projects such as UFAST. The high flow quality parameters and the wide range of testing capabilities ensure the competitivity of the tunnel at an international level.

In-mine (tunnel-to-tunnel) electrical resistance tomography in South African platinum mines

CSIR Research Space (South Africa)

Van Schoor, Abraham M

2009-12-01

Full Text Available The applicability of tunnel-to-tunnel electrical resistance tomography (ERT) for imaging disruptive geological structures ahead of mining, in an igneous platinum mining environment is assessed. The geophysical targets of interest are slump...

Destructive quantum interference in spin tunneling problems

OpenAIRE

von Delft, Jan; Henley, Christopher L.

1992-01-01

In some spin tunneling problems, there are several different but symmetry-related tunneling paths that connect the same initial and final configurations. The topological phase factors of the corresponding tunneling amplitudes can lead to destructive interference between the different paths, so that the total tunneling amplitude is zero. In the study of tunneling between different ground state configurations of the Kagom\\'{e}-lattice quantum Heisenberg antiferromagnet, this occurs when the spi...

Snow and ice blocking of tunnels

Energy Technology Data Exchange (ETDEWEB)

Lia, Leif

1998-12-31

Hydroelectric power development in cold regions causes much concern about operational reliability and dam safety. This thesis studies the temperature distribution in tunnels by means of air temperature measurements in six tunnel spillways and five diversion tunnels. The measurements lasted for two consecutive winters. The air through flow tunnel is used as it causes cooling of both rock and water. In open spillway tunnels, frost reaches the entire tunnel. In spillway tunnels with walls, the frost zones reach about 100 m from the downstream end. In mildly-inclined diversion tunnels, a frost free zone is located in the middle of the tunnel and snow and ice problems were only observed in the inlet and outlet. Severe aufeis is accumulation is observed in the frost zones. The heat transfer from rock to air, water and ice is calculated and used in a prediction model for the calculation of aufeis build-up together with local field observation data. The water penetration of snow plugs is also calculated, based on the heat balance. It takes 20 to 50 days for water to enter the blocked tunnel. The empirical values are 30 to 60 days, but only 1 day if the temperature of the snow pack is 0{sup o}C. Sensitivity analyses are carried out for temperature variations in rock, snow, water and ice. Systematic field observation shows that it is important for hydropower companies to know about the effects of snow and ice blocking in an area. A risk analysis of dam safety is presented for a real case. Finally, the thesis proposes solutions which can reduce the snow and ice problems. 79 refs., 63 figs., 11 tabs.

Investigation of Corner Effect and Identification of Tunneling Regimes in L-Shaped Tunnel Field-Effect-Transistor.

Science.gov (United States)

Najam, Faraz; Yu, Yun Seop

2018-09-01

Corner-effect existing in L-shaped tunnel field-effect-transistor (LTFET) was investigated using numerical simulations and band diagram analysis. It was found that the corner-effect is caused by the convergence of electric field in the sharp source corner present in an LTFET, thereby increasing the electric field in the sharp source corner region. It was found that in the corner-effect region tunneling starts early, as a function of applied bias, as compared to the rest of the channel not affected by corner-effect. Further, different tunneling regimes as a function of applied bias were identified in the LTFET including source to channel and channel to channel tunneling regimes. Presence of different tunneling regimes in LTFET was analytically justified with a set of equations developed to model source to channel, and channel to channel tunneling currents. Drain-current-gate-voltage (Ids-Vgs) characteristics obtained from the equations is in reasonable qualitative agreement with numerical simulation.

Scanning Tunneling Optical Resonance Microscopy

Science.gov (United States)

Bailey, Sheila; Wilt, Dave; Raffaelle, Ryne; Gennett, Tom; Tin, Padetha; Lau, Janice; Castro, Stephanie; Jenkins, Philip; Scheiman, Dave

2003-01-01

Scanning tunneling optical resonance microscopy (STORM) is a method, now undergoing development, for measuring optoelectronic properties of materials and devices on the nanoscale by means of a combination of (1) traditional scanning tunneling microscopy (STM) with (2) tunable laser spectroscopy. In STORM, an STM tip probing a semiconductor is illuminated with modulated light at a wavelength in the visible-to-near-infrared range and the resulting photoenhancement of the tunneling current is measured as a function of the illuminating wavelength. The photoenhancement of tunneling current occurs when the laser photon energy is sufficient to excite charge carriers into the conduction band of the semiconductor. Figure 1 schematically depicts a proposed STORM apparatus. The light for illuminating the semiconductor specimen at the STM would be generated by a ring laser that would be tunable across the wavelength range of interest. The laser beam would be chopped by an achromatic liquid-crystal modulator. A polarization-maintaining optical fiber would couple the light to the tip/sample junction of a commercial STM. An STM can be operated in one of two modes: constant height or constant current. A STORM apparatus would be operated in the constant-current mode, in which the height of the tip relative to the specimen would be varied in order to keep the tunneling current constant. In this mode, a feedback control circuit adjusts the voltage applied to a piezoelectric actuator in the STM that adjusts the height of the STM tip to keep the tunneling current constant. The exponential relationship between the tunneling current and tip-to-sample distance makes it relatively easy to implement this mode of operation. The choice of method by which the photoenhanced portion of the tunneling current would be measured depends on choice of the frequency at which the input illumination would be modulated (chopped). If the frequency of modulation were low enough (typically tunneling current

Fiber coupled ultrafast scanning tunneling microscope

DEFF Research Database (Denmark)

Keil, Ulrich Dieter Felix; Jensen, Jacob Riis; Hvam, Jørn Märcher

1997-01-01

We report on a scanning tunneling microscope with a photoconductive gate in the tunneling current circuit. The tunneling tip is attached to a coplanar transmission line with an integrated photoconductive switch. The switch is illuminated through a fiber which is rigidly attached to the switch...... waveguide. The measurements show that the probe works as a transient voltage detector in contact and a capacitively coupled transient field detector in tunneling mode. We do not measure the transient voltage change in the ohmic tunneling current. In this sense, the spatial resolution for propagating...... substrate. By using a firmly attached fiber we achieve an excellent reproducibility and unconstrained positioning of the tip. We observe a transient signal with 2.9 ps pulse width in tunneling mode and 5 ps in contact mode. The instrument is applied to investigating the mode structure on a coplanar...

Experimental Evidence for Quantum Tunneling Time

Science.gov (United States)

Camus, Nicolas; Yakaboylu, Enderalp; Fechner, Lutz; Klaiber, Michael; Laux, Martin; Mi, Yonghao; Hatsagortsyan, Karen Z.; Pfeifer, Thomas; Keitel, Christoph H.; Moshammer, Robert

2017-07-01

The first hundred attoseconds of the electron dynamics during strong field tunneling ionization are investigated. We quantify theoretically how the electron's classical trajectories in the continuum emerge from the tunneling process and test the results with those achieved in parallel from attoclock measurements. An especially high sensitivity on the tunneling barrier is accomplished here by comparing the momentum distributions of two atomic species of slightly deviating atomic potentials (argon and krypton) being ionized under absolutely identical conditions with near-infrared laser pulses (1300 nm). The agreement between experiment and theory provides clear evidence for a nonzero tunneling time delay and a nonvanishing longitudinal momentum of the electron at the "tunnel exit."

Effectiveness of low-level laser therapy for patients with carpal tunnel syndrome: design of a randomized single-blinded controlled trial

Directory of Open Access Journals (Sweden)

Barbosa Rafael Inácio

2012-12-01

Full Text Available Abstract Background Carpal tunnel syndrome is the most common neuropathy in the upper extremity, resulting from the compression of the median nerve at wrist level. Clinical studies are essentials to present evidence on therapeutic resources use at early restoration on peripheral nerve functionality. Low-level laser therapy has been widely investigated in researches related to nerve regeneration. Therefore, it is suggested that the effect of low-level laser therapy associated with other conservative rehabilitation techniques may positively affect symptoms and overall hand function in compressive neuropathies such as carpal tunnel syndrome. The aim of this study is to evaluate the effectiveness of low-level laser therapy in addition to orthoses therapy and home orientations in patients with carpal tunnel syndrome. Methods/Design Patients older than 18 years old will be included, with clinical diagnosis of carpal tunnel syndrome, excluding comorbidies. A physiotherapist will conduct intervention, with a blinding evaluator. Randomization will be applied to allocate the patients in each group: with association or not to low-level laser therapy. All of them will be submitted to orthoses therapy and home orientations. Outcome will be assessed through: pain visual analogic scale, Semmes Weinstein monofilaments™ threshold sensibility test, Pinch Gauge™, Boston Carpal Tunnel Questionnaire and two point discrimination test. Discussion This paper describes the design of a randomized controlled trial, which aim to assess the effectiveness of conservative treatment added to low-level laser therapy for patients with carpal tunnel syndrome. Trial registration Brazilian Clinical Trials Registry (ReBec - 75ddtf / Universal Trial Number: U1111-1121-5184

Tunneling from the past horizon

Science.gov (United States)

Kang, Subeom; Yeom, Dong-han

2018-04-01

We investigate a tunneling and emission process of a thin-shell from a Schwarzschild black hole, where the shell was initially located beyond the Einstein-Rosen bridge and finally appears at the right side of the Penrose diagram. In order to obtain such a solution, we should assume that the areal radius of the black hole horizon increases after the tunneling. Hence, there is a parameter range such that the tunneling rate is exponentially enhanced, rather than suppressed. We may have two interpretations regarding this. First, such a tunneling process from the past horizon is improbable by physical reasons; second, such a tunneling is possible in principle, but in order to obtain a stable Einstein-Rosen bridge, one needs to restrict the parameter spaces. If such a process is allowed, this can be a nonperturbative contribution to Einstein-Rosen bridges as well as eternal black holes.

Molecular series-tunneling junctions.

Science.gov (United States)

Liao, Kung-Ching; Hsu, Liang-Yan; Bowers, Carleen M; Rabitz, Herschel; Whitesides, George M

2015-05-13

Charge transport through junctions consisting of insulating molecular units is a quantum phenomenon that cannot be described adequately by classical circuit laws. This paper explores tunneling current densities in self-assembled monolayer (SAM)-based junctions with the structure Ag(TS)/O2C-R1-R2-H//Ga2O3/EGaIn, where Ag(TS) is template-stripped silver and EGaIn is the eutectic alloy of gallium and indium; R1 and R2 refer to two classes of insulating molecular units-(CH2)n and (C6H4)m-that are connected in series and have different tunneling decay constants in the Simmons equation. These junctions can be analyzed as a form of series-tunneling junctions based on the observation that permuting the order of R1 and R2 in the junction does not alter the overall rate of charge transport. By using the Ag/O2C interface, this system decouples the highest occupied molecular orbital (HOMO, which is localized on the carboxylate group) from strong interactions with the R1 and R2 units. The differences in rates of tunneling are thus determined by the electronic structure of the groups R1 and R2; these differences are not influenced by the order of R1 and R2 in the SAM. In an electrical potential model that rationalizes this observation, R1 and R2 contribute independently to the height of the barrier. This model explicitly assumes that contributions to rates of tunneling from the Ag(TS)/O2C and H//Ga2O3 interfaces are constant across the series examined. The current density of these series-tunneling junctions can be described by J(V) = J0(V) exp(-β1d1 - β2d2), where J(V) is the current density (A/cm(2)) at applied voltage V and βi and di are the parameters describing the attenuation of the tunneling current through a rectangular tunneling barrier, with width d and a height related to the attenuation factor β.

Automated Boundary Conditions for Wind Tunnel Simulations

Science.gov (United States)

Carlson, Jan-Renee

2018-01-01

Computational fluid dynamic (CFD) simulations of models tested in wind tunnels require a high level of fidelity and accuracy particularly for the purposes of CFD validation efforts. Considerable effort is required to ensure the proper characterization of both the physical geometry of the wind tunnel and recreating the correct flow conditions inside the wind tunnel. The typical trial-and-error effort used for determining the boundary condition values for a particular tunnel configuration are time and computer resource intensive. This paper describes a method for calculating and updating the back pressure boundary condition in wind tunnel simulations by using a proportional-integral-derivative controller. The controller methodology and equations are discussed, and simulations using the controller to set a tunnel Mach number in the NASA Langley 14- by 22-Foot Subsonic Tunnel are demonstrated.

Redesigning dehalogenase access tunnels as a strategy for degrading an anthropogenic substrate.

Science.gov (United States)

Pavlova, Martina; Klvana, Martin; Prokop, Zbynek; Chaloupkova, Radka; Banas, Pavel; Otyepka, Michal; Wade, Rebecca C; Tsuda, Masataka; Nagata, Yuji; Damborsky, Jiri

2009-10-01

Engineering enzymes to degrade anthropogenic compounds efficiently is challenging. We obtained Rhodococcus rhodochrous haloalkane dehalogenase mutants with up to 32-fold higher activity than wild type toward the toxic, recalcitrant anthropogenic compound 1,2,3-trichloropropane (TCP) using a new strategy. We identified key residues in access tunnels connecting the buried active site with bulk solvent by rational design and randomized them by directed evolution. The most active mutant has large aromatic residues at two out of three randomized positions and two positions modified by site-directed mutagenesis. These changes apparently enhance activity with TCP by decreasing accessibility of the active site for water molecules, thereby promoting activated complex formation. Kinetic analyses confirmed that the mutations improved carbon-halogen bond cleavage and shifted the rate-limiting step to the release of products. Engineering access tunnels by combining computer-assisted protein design with directed evolution may be a valuable strategy for refining catalytic properties of enzymes with buried active sites.

FUNDAMENTAL TUNNELING PROCESSES IN MOSa SOLAR CELLS

OpenAIRE

Balberg , I.; Hanak , J.; Weakliem , H.; Gal , E.

1981-01-01

In previous studies of tunneling through a MOSa tunnel junction, where Sa was a-Si : H, it was shown that their characteristics resemble those of MOSc devices where Sc was crystalline silicon. In the present work we would like to report a demonstration of fundamental tunneling processes in such tunnel junctions. In particular, the transition from semiconductor controlled regime to tunneling controlled regime can be clearly distinguished. The present results represent one of the rare cases whe...

Distribution of tunnelling times for quantum electron transport

International Nuclear Information System (INIS)

Rudge, Samuel L.; Kosov, Daniel S.

2016-01-01

In electron transport, the tunnelling time is the time taken for an electron to tunnel out of a system after it has tunnelled in. We define the tunnelling time distribution for quantum processes in a dissipative environment and develop a practical approach for calculating it, where the environment is described by the general Markovian master equation. We illustrate the theory by using the rate equation to compute the tunnelling time distribution for electron transport through a molecular junction. The tunnelling time distribution is exponential, which indicates that Markovian quantum tunnelling is a Poissonian statistical process. The tunnelling time distribution is used not only to study the quantum statistics of tunnelling along the average electric current but also to analyse extreme quantum events where an electron jumps against the applied voltage bias. The average tunnelling time shows distinctly different temperature dependence for p- and n-type molecular junctions and therefore provides a sensitive tool to probe the alignment of molecular orbitals relative to the electrode Fermi energy.

Een systeem voor classificatie van korte tunnels.

NARCIS (Netherlands)

Schreuder, D.A.

1985-01-01

The most difficult problems in the lighting of tunnels occur in daylight and in particular in the entrance of the tunnel, while drivers approaching the tunnel must be able to look into the tunnel from the outside to detect the road course and eventual obstacles. A classification should The made on

Effects of the finite duration of quantum tunneling in laser-assisted scanning tunneling microscopy

International Nuclear Information System (INIS)

Hagmann, M.J.

1994-01-01

Previous measurements of tunnel conductance in heterostructures and experiments with Josephson junctions suggest quantum tunneling has a definite duration. The authors use semiclassical methods to determine the effects of this delay on the tunneling current in a laser-assisted STM. A planar-planar STM model is used with the exact multiple image potential, and the energy distribution for a free-electron metal. It is necessary to average over the phase at barrier entry, and iteration with back propagated solutions is required to obtain the transmission coefficients for evenly spaced phases and specified energies at barrier entry. The simulations suggest that the dependence of the tunneling current on the wavelength of illumination can serve as a basis for determining the duration of barrier traversal. A power flux density of 10 11 W/m 2 would be required at several wavelengths from 1 to 10 μm. It is possible that thermal effects could be separated from the modeled phenomena by determining the time dependence of the tunneling current with a pulsed laser

Dependences of the Tunnel Magnetoresistance and Spin Transfer Torque on the Sizes and Concentration of Nanoparticles in Magnetic Tunnel Junctions

Science.gov (United States)

Esmaeili, A. M.; Useinov, A. N.; Useinov, N. Kh.

2018-01-01

Dependences of the tunnel magnetoresistance and in-plane component of the spin transfer torque on the applied voltage in a magnetic tunnel junction have been calculated in the approximation of ballistic transport of conduction electrons through an insulating layer with embedded magnetic or nonmagnetic nanoparticles. A single-barrier magnetic tunnel junction with a nanoparticle embedded in an insulator forms a double-barrier magnetic tunnel junction. It has been shown that the in-plane component of the spin transfer torque in the double-barrier magnetic tunnel junction can be higher than that in the single-barrier one at the same thickness of the insulating layer. The calculations show that nanoparticles embedded in the tunnel junction increase the probability of tunneling of electrons, create resonance conditions, and ensure the quantization of the conductance in contrast to the tunnel junction without nanoparticles. The calculated dependences of the tunnel magnetoresistance correspond to experimental data demonstrating peak anomalies and suppression of the maximum magnetoresistances at low voltages.

Proceedings of the meeting on tunneling reaction and low temperature chemistry, 98 August. Tunneling reaction and its theory

Energy Technology Data Exchange (ETDEWEB)

Miyazaki, Tetsuo; Aratono, Yasuyuki; Ichikawa, Tsuneki; Shiotani, Masaru [eds.

1998-10-01

Present report is the proceedings of the 4th Meeting on Tunneling Reaction and Low Temperature Chemistry held in August 3 and 4, 1998. The main subject of the meeting is `Tunneling Reaction and Its Theory`. In the present meeting the theoretical aspects of tunneling phenomena in the chemical reaction were discussed intensively as the main topics. Ten reports were presented on the quantum diffusion of muon and proton in the metal and H{sub 2}{sup -} anion in the solid para-hydrogen, the theory of tunnel effect in the nuclear reaction and the tunneling reaction in the organic compounds. One special lecture was presented by Prof. J. Kondo on `Proton Tunneling in Solids`. The 11 of the presented papers are indexed individually. (J.P.N.)

Strain-enhanced tunneling magnetoresistance in MgO magnetic tunnel junctions.

Science.gov (United States)

Loong, Li Ming; Qiu, Xuepeng; Neo, Zhi Peng; Deorani, Praveen; Wu, Yang; Bhatia, Charanjit S; Saeys, Mark; Yang, Hyunsoo

2014-09-30

While the effects of lattice mismatch-induced strain, mechanical strain, as well as the intrinsic strain of thin films are sometimes detrimental, resulting in mechanical deformation and failure, strain can also be usefully harnessed for applications such as data storage, transistors, solar cells, and strain gauges, among other things. Here, we demonstrate that quantum transport across magnetic tunnel junctions (MTJs) can be significantly affected by the introduction of controllable mechanical strain, achieving an enhancement factor of ~2 in the experimental tunneling magnetoresistance (TMR) ratio. We further correlate this strain-enhanced TMR with coherent spin tunneling through the MgO barrier. Moreover, the strain-enhanced TMR is analyzed using non-equilibrium Green's function (NEGF) quantum transport calculations. Our results help elucidate the TMR mechanism at the atomic level and can provide a new way to enhance, as well as tune, the quantum properties in nanoscale materials and devices.

Clinical Outcomes after Arthroscopic Release for Recalcitrant Frozen Shoulder

OpenAIRE

Ebrahimzadeh, Mohammad H; Moradi, Ali; Pour, Mostafa Khalili; Moghadam, Mohammad Hallaj; Kachooei, Amir Reza

2014-01-01

Background: To explain the role of arthroscopic release in intractable frozen shoulders. We used different questionnaires and measuring tools to understand whether arthroscopic release is the superior modality to treat patients with intractable frozen shoulders. Methods: Between 2007 and 2013, in a prospective study, we enrolled 80 patients (52 females and 28 males) with recalcitrant frozen shoulder, who underwent arthroscopic release at Ghaem Hospital, a tertiary referral center, in Mashhad,...

Trap assisted tunneling and its effect on subthreshold swing of tunnel field effect transistors

OpenAIRE

Sajjad, Redwan N.; Chern, Winston; Hoyt, Judy L.; Antoniadis, Dimitri A.

2016-01-01

We provide a detailed study of the interface Trap Assisted Tunneling (TAT) mechanism in tunnel field effect transistors to show how it contributes a major leakage current path before the Band To Band Tunneling (BTBT) is initiated. With a modified Shockley-Read-Hall formalism, we show that at room temperature, the phonon assisted TAT current always dominates and obscures the steep turn ON of the BTBT current for common densities of traps. Our results are applicable to top gate, double gate and...

Ultrasound evaluation on carpal tunnel syndrome before and after bariatric surgery

Directory of Open Access Journals (Sweden)

Adham do Amaral e Castro

Full Text Available Objective:To evaluate the prevalence of carpal tunnel syndrome in candidates for bariatric surgery comparing with the non-obese population and verify the effects on it of bariatric treatment. Methods:We studiedthree groups of individuals: 1 patients waiting for bariatric surgery (preoperative; 2 individuals who had already undergone the procedure (postoperative; and 3 control group. We collected demographic and clinical data of carpal tunnel syndrome. The Ultrasound examination was carried out to diagnose the syndrome by measuring the median nerve area. Results:We included 329 individuals (114 in the preoperative group, 90 in the postoperative group and 125 controls. There was a higher prevalence of paresthesias (p=0.0003, clinical tests (p=0.0083 on the preoperative group when compared with controls (p<0.00001. There were lowe levels of paresthesias (p=0.0002 and median nerve area (p=0.04 in postoperative patients but with no significant difference in general. A significant difference was found between the preoperative and postoperative groups (p=0.05 in those who performed non-manual work.Conclusion: There was a higher prevalence of carpal tunnel syndrome in the preoperative group compared with the control one, but no significant difference was observed between the pre and postoperative groups in general. There was difference between pre and postoperative groups for non-manual workers.

78 FR 46117 - National Tunnel Inspection Standards

Science.gov (United States)

2013-07-30

... busiest vehicular tunnel in the world. The Fort McHenry Tunnel handles a daily traffic volume of more than... vehicular, transit, and rail tunnels in the New York City metropolitan area. Although it is still too early... congestion along alternative routes, and save users both dollars and fuel. If these tunnels were closed due...

Tunnel nitrogen spill experiment

International Nuclear Information System (INIS)

Ageyev, A.I.; Alferov, V.N.; Mulholland, G.T.

1983-01-01

The Energy Saver Safety Analysis Report (SAR) found the tunnel oxygen deficiency considerations emphasized helium spills. These reports concluded the helium quickly warms and because of its low denisty, rises to the apex of the tunnel. The oxygen content below the apex and in all but the immediate vicinity of the helium spill is essentially unchanged and guarantees an undisturbed source of oxygen especially important to fallen personnel. In contrast nitrogen spills warm slower than helium due to the ratio of the enthalpy changes per unit volume spilled spread more uniformly across the tunnel cross-section when warmed because of the much smaller density difference with air, and generally provides a greater hazard than helium spills as a result. In particular there was concern that personnel that might fall to the floor for oxygen deficiency or other reasons might find less, and not more, oxygen with dire consequences. The SAR concluded tunnel nitrogen spills were under-investigated and led to this work

Coordinated clinical and financial analysis as a powerful tool to influence vendor pricing.

Science.gov (United States)

Logan, Catherine A; Wu, Roger Y; Mulley, Debra; Smith, Paul C; Schwaitzberg, Steven D

2010-01-01

As costs continue to outpace reimbursements, hospital administrators and clinicians face increasing pressure to justify new capital purchases. Massachusetts Health Care Reform has added further economic challenges for Disproportionate Share Hospitals (DSH), as resources formerly available to treat the uninsured have been redirected. In this challenging climate, many hospitals still lack a standardized process for technology planning and/or vendor negotiation. : The purpose of this study was to determine whether a simple, coordinated clinical and financial analysis of a technology, Endoscopic Carpal Tunnel Release (ECTR), is sufficient to impact vendor pricing at Cambridge Health Alliance (CHA), a disproportionate share hospital (DSH) in Cambridge, Massachusetts. This case study addressed the topic of technology adoption, a complex decision-making process every hospital administration faces. Taking note of other hospitals approaches to instill a strategic management culture, CHA combined a literature review on clinical outcomes and financial analysis on profitability. Clinical effectiveness was evaluated through a literature review. The financial analysis was based on a retrospective inquiry of fixed and variable costs, reimbursement rates, actual payer mix, and profitability of adopting ECTR over open carpal tunnel release at CHA. This clinical and financial analysis was then shared with the vendor. A literature review revealed that although there are short-term benefits to ECTR, there is little to no difference in long-term outcomes to justify a calculated incremental loss of $91.49 in revenue per case. Sharing this analysis with the vendor resulted in a 30% price reduction. A revised cost analysis demonstrated a $53.51 incremental gain in revenue per case. CHA has since elected to offer ECTR to its patients. Smaller hospital systems often have modest leverage in vendor negotiations. Our results suggest that the development of adoption criteria and an evidence

New generation of free-piston shock tunnels

Science.gov (United States)

Morrison, W. R. B.; Stalker, R. J.; Duffin, J.

1990-01-01

Consideration is given to three free-piston driven hypersonic tunnels under construction that will greatly enhance existing test capabilities. The tunnel being built at Caltech will feature energy capabilities about 40 percent higher than those of the world's largest operational free-piston tunnel to date. The second tunnel under construction will allow full-size engine hardware at near-orbital speeds. The third facility is a high-performance expansion tube that will be capable of generating high enthalpy flows at speeds of up to 9 km/sec. It will provide flows with dissociation levels much lower than are attainable with a reflected shock tunnel, approaching actual flight conditions. A table shows the tunnels' characteristics.

Geological Prediction Ahead of Tunnel Face in the Limestone Formation Tunnel using Multi-Modal Geophysical Surveys

Science.gov (United States)

Zaki, N. F. M.; Ismail, M. A. M.; Hazreek Zainal Abidin, Mohd; Madun, Aziman

2018-04-01

Tunnel construction in typical karst topography face the risk which unknown geological condition such as abundant rainwater, ground water and cavities. Construction of tunnel in karst limestone frequently lead to potentially over-break of rock formation and cause failure to affected area. Physical character of limestone which consists large cavity prone to sudden failure and become worsen due to misinterpretation of rock quality by engineer and geologists during analysis stage and improper method adopted in construction stage. Consideration for execution of laboratory and field testing in rock limestone should be well planned and arranged in tunnel construction project. Several tests including Ground Penetration Radar (GPR) and geological face mapping were studied in this research to investigate the performances of limestone rock in tunnel construction, measured in term of rock mass quality that used for risk assessment. The objective of this study is to focus on the prediction of geological condition ahead of tunnel face using short range method (GPR) and verified by geological face mapping method to determine the consistency of actual geological condition on site. Q-Value as the main indicator for rock mass classification was obtained from geological face mapping method. The scope of this study is covering for tunnelling construction along 756 meters in karst limestone area which located at Timah Tasoh Tunnel, Bukit Tebing Tinggi, Perlis. For this case study, 15% of GPR results was identified as inaccurate for rock mass classification in which certain chainage along this tunnel with 34 out of 224 data from GPR was identified as incompatible with actual face mapping.

The etiology of idiopathic carpal tunnel syndrome. Evaluation from the viewpoint of magnetic resonance imaging

International Nuclear Information System (INIS)

Ikeda, Jun

2003-01-01

The etiology of idiopathic carpal tunnel syndrome has not been clarified. A cross sectional area of carpal tunnel, flexor tendons, median nerve, and thickness of transverse carpal ligament were evaluated by MRI. Twenty-six patients who were electrophysiologically diagnosed with idiopathic carpal tunnel syndrome were tested by MRI. All patients were females; the mean age was sixty-four years old. The cross sectional area of carpal tunnel, the median nerve area, the area of the flexor tendons and its synovium in carpal tunnel, and thickness of the transverse carpal ligament were calculated. The following are of a seuere type carpal tunnel syndrome: Mean area of the flexor tendons and its synovium in carpal tunnel, 110.5±25.5 mm 2 (control group; 79.3±13.8 mm 2 ); ratio of flexor tendons and its synovium area to carpal tunnel area, 51.6±8.8% (control; 40.5±2.3%); and thickness of the transverse carpal ligament, 3.3±0.4 mm (control; 2.4±0.4 mm). These mean areas in severe carpal tunnel syndrome were significantly greater than those in mild type (p<0.05 or p<0.01). From the viewpoint of this result, it is possible that tenosynovitis is strongly to the etiology of idiopathic carpal tunnel syndrome. In other words, synovium edema causes chronic high pressure environment in carpal tunnel. Moreover, we classified these MRI findings into the following subgroups: enlargement of cross sectional area of flexor tendon and its synovia (n=8; 25.8%), thickened transverse carpal ligament (n=11; 35.5%), and combined type (n=7; 22.6%). This classification by MRI imaging was related to a clinical course and electro-physiologic severity. The present study suggests that to evaluate the cross sectional, area of an MRI image is useful for diagnosis and cure of idiopathic carpal tunnel syndrome. (author)

D Modelling of Tunnel Excavation Using Pressurized Tunnel Boring Machine in Overconsolidated Soils

Science.gov (United States)

Demagh, Rafik; Emeriault, Fabrice

2013-06-01

The construction of shallow tunnels in urban areas requires a prior assessment of their effects on the existing structures. In the case of shield tunnel boring machines (TBM), the various construction stages carried out constitute a highly three-dimensional problem of soil/structure interaction and are not easy to represent in a complete numerical simulation. Consequently, the tunnelling- induced soil movements are quite difficult to evaluate. A 3D simulation procedure, using a finite differences code, namely FLAC3D, taking into account, in an explicit manner, the main sources of movements in the soil mass is proposed in this paper. It is illustrated by the particular case of Toulouse Subway Line B for which experimental data are available and where the soil is saturated and highly overconsolidated. A comparison made between the numerical simulation results and the insitu measurements shows that the 3D procedure of simulation proposed is relevant, in particular regarding the adopted representation of the different operations performed by the tunnel boring machine (excavation, confining pressure, shield advancement, installation of the tunnel lining, grouting of the annular void, etc). Furthermore, a parametric study enabled a better understanding of the singular behaviour origin observed on the ground surface and within the solid soil mass, till now not mentioned in the literature.

Tunneling Flight Time, Chemistry, and Special Relativity.

Science.gov (United States)

Petersen, Jakob; Pollak, Eli

2017-09-07

Attosecond ionization experiments have not resolved the question "What is the tunneling time?". Different definitions of tunneling time lead to different results. Second, a zero tunneling time for a material particle suggests that the nonrelativistic theory includes speeds greater than the speed of light. Chemical reactions, occurring via tunneling, should then not be considered in terms of a nonrelativistic quantum theory calling into question quantum dynamics computations on tunneling reactions. To answer these questions, we define a new experimentally measurable paradigm, the tunneling flight time, and show that it vanishes for scattering through an Eckart or a square barrier, irrespective of barrier length or height, generalizing the Hartman effect. We explain why this result does not lead to experimental measurement of speeds greater than the speed of light. We show that this tunneling is an incoherent process by comparing a classical Wigner theory with exact quantum mechanical computations.

3D Numerical Modeling of Pile Group Responses to Excavation-Induced Stress Release in Silty Clay

Directory of Open Access Journals (Sweden)

M. A. Soomro

2018-02-01

Full Text Available Development of underground transportation systems consists of tunnels, basement construction excavations and cut and cover tunnels which may encounter existing pile groups during their construction. Since many previous studies mainly focus on the effects of excavations on single piles, settlement and load transfer mechanism of a pile group subjected to excavation-induced stress release are not well investigated and understood. To address these two issues, three-dimensional coupled-consolidation numerical analysis is conducted by using a hypoplastic model which takes small-strain stiffness into account. A non-linear pile group settlement was induced. This may be attributed to reduction of shaft resistance due to excavation induced stress release, the pile had to settle substantially to further mobilise end-bearing. Compared to the Sp of the pile group, induced settlement of the single pile is larger with similar settlement characteristics. Due to the additional settlement of the pile group, factor of safety for the pile group can be regarded as decreasing from 3.0 to 1.4, based on a displacement-based failure load criterion. Owing to non-uniform stress release, pile group tilted towards the excavation with value of 0.14%. Due to excavation-induced stress release and dragload, head load of rear piles was reduced and transferred to rear piles. This load transfer can increase the axial force in front piles by 94%.

Tunnel Face Stability & New CPT Applications

NARCIS (Netherlands)

Broere, W.

2001-01-01

Nearly all tunnels bored in soft soils have encountered problems with the stability of the tunnel face. In several cases these problems led to an extended stand-still of the boring process. A better understanding of the face stability, and of the soil conditions around the tunnel boring machine, can

Shaft and tunnel sealing considerations

International Nuclear Information System (INIS)

Kelsall, P.C.; Shukla, D.K.

1980-01-01

Much of the emphasis of previous repository sealing research has been placed on plugging small diameter boreholes. It is increasingly evident that equal emphasis should now be given to shafts and tunnels which constitute more significant pathways between a repository and the biosphere. The paper discusses differences in requirements for sealing shafts and tunnels as compared with boreholes and the implications for seal design. Consideration is given to a design approach for shaft and tunnel seals based on a multiple component design concept, taking into account the requirements for retrievability of the waste. A work plan is developed for the future studies required to advance shaft and tunnel sealing technology to a level comparable with the existing technology for borehole sealing

The Effect of Control-released Basic Fibroblast Growth Factor in Wound Healing: Histological Analyses and Clinical Application

Directory of Open Access Journals (Sweden)

Shigeru Matsumoto, MD

2013-09-01

Conclusions: These findings suggest that control-released bFGF using gelatin sheet is effective for promoting wound healing. Such therapeutic strategy was considered to offer several clinical advantages including rapid healing and reduction of the dressing change with less patient discomfort.

Computational Multiqubit Tunnelling in Programmable Quantum Annealers

Science.gov (United States)

2016-08-25

ARTICLE Received 3 Jun 2015 | Accepted 26 Nov 2015 | Published 7 Jan 2016 Computational multiqubit tunnelling in programmable quantum annealers...state itself. Quantum tunnelling has been hypothesized as an advantageous physical resource for optimization in quantum annealing. However, computational ...qubit tunnelling plays a computational role in a currently available programmable quantum annealer. We devise a probe for tunnelling, a computational

Sustained-release progesterone vaginal suppositories 1--development of sustained-release granule--.

Science.gov (United States)

Nakayama, Ayako; Sunada, Hisakazu; Okamoto, Hirokazu; Furuhashi, Kaoru; Ohno, Yukiko; Ito, Mikio

2009-02-01

Progesterone (P) is an important hormone for the establishment of pregnancy, and its administration is useful for luteal insufficiency. Considering the problems of commercially available oral and injection drugs, hospital-formulated vaginal suppositories are clinically used. However, since the half-life of P suppositories is short, it is difficult to maintain its constant blood concentration. To sustain drug efficacy and prevent side-effects, we are attempting to develop sustained-release suppositories by examining the degree of sustained-release of active ingredients. In this study, we examined the combinations of granulation methods and release systems for the preparation of sustained-release granules of P, and produced 13 types of sustained-release granules. We also examined the diameter, content, and dissolution of each type of granules, and confirmed that the sustained-release of all types of granules was satisfactory. Among the sustained-release granules, we selected granules with a content and a degree of sustained-release suitable for sustained-release suppositories.

The Usefulness of the Preoperative Magnetic Resonance Imaging Findings in the Evaluation of Tarsal Tunnel Syndrome

Energy Technology Data Exchange (ETDEWEB)

Jung, Hyun Jin; Lee, Sheen Woo; Jeong, Yu Mi; Choi, Hye Young; Kim, Hyung Sik [Dept. of Radiology, Gil Hospital, Gacheon University College of Medicine, Incheon (Korea, Republic of); Park, Hong Gi; Kwak, Ji Hoon [Dept. of Orthopedic Surgery, Gil Hospital, Gacheon University College of Medicine, Incheon (Korea, Republic of)

2012-02-15

The purpose of this study was to access the diverse conditions that lead to the clinical manifestations of tarsal tunnel syndrome and evaluate the usefulness of magnetic resonance imaging (MRI) in preoperative evaluation. Thirty-three patients who underwent ankle MRI and surgery under the impression of tarsal tunnel syndrome were retrospectively analyzed. The findings on ankle MRI were categorized into space occupying lesions within the tarsal tunnel, space occupying lesions of the tunnel wall, and non-space occupying lesions. Associated plantar muscle atrophy was also evaluated. Medical records were reviewed for correlation of nerve conduction velocity (NCV) and surgical findings. There were 21 space occupying lesions of the tarsal tunnel, and eight lesions of tarsal tunnel wall. There were three cases with accessory muscle, three with tarsal coalition, five with ganglion cysts, one neurogenic tumor, five flexor retinaculum hypertrophy, three varicose veins, and nine with tenosynovitis of the posterior tibialis, flexor digitorum longus, or flexor hallucis longus tendon. One patient was found to have a deltoid ligament sprain. Of the 32, eight patients experienced fatty atrophic change within any one of the foot muscles. NCV was positive in 79% of the MRI-positive lesions. MRI provides detailed information on ankle anatomy, which includes that of tarsal tunnel and beyond. Pathologic conditions that cause or mimic tarsal tunnel syndrome are well demonstrated. MRI can enhance surgical planning by indicating the extent of decompression required, and help with further patient management. Patients with tarsal tunnel syndrome can greatly benefit from preoperative MRI. However, it should be noted that not all cases with tarsal tunnel syndrome have MRI-demonstrable causes.

The Usefulness of the Preoperative Magnetic Resonance Imaging Findings in the Evaluation of Tarsal Tunnel Syndrome

International Nuclear Information System (INIS)

Jung, Hyun Jin; Lee, Sheen Woo; Jeong, Yu Mi; Choi, Hye Young; Kim, Hyung Sik; Park, Hong Gi; Kwak, Ji Hoon

2012-01-01

The purpose of this study was to access the diverse conditions that lead to the clinical manifestations of tarsal tunnel syndrome and evaluate the usefulness of magnetic resonance imaging (MRI) in preoperative evaluation. Thirty-three patients who underwent ankle MRI and surgery under the impression of tarsal tunnel syndrome were retrospectively analyzed. The findings on ankle MRI were categorized into space occupying lesions within the tarsal tunnel, space occupying lesions of the tunnel wall, and non-space occupying lesions. Associated plantar muscle atrophy was also evaluated. Medical records were reviewed for correlation of nerve conduction velocity (NCV) and surgical findings. There were 21 space occupying lesions of the tarsal tunnel, and eight lesions of tarsal tunnel wall. There were three cases with accessory muscle, three with tarsal coalition, five with ganglion cysts, one neurogenic tumor, five flexor retinaculum hypertrophy, three varicose veins, and nine with tenosynovitis of the posterior tibialis, flexor digitorum longus, or flexor hallucis longus tendon. One patient was found to have a deltoid ligament sprain. Of the 32, eight patients experienced fatty atrophic change within any one of the foot muscles. NCV was positive in 79% of the MRI-positive lesions. MRI provides detailed information on ankle anatomy, which includes that of tarsal tunnel and beyond. Pathologic conditions that cause or mimic tarsal tunnel syndrome are well demonstrated. MRI can enhance surgical planning by indicating the extent of decompression required, and help with further patient management. Patients with tarsal tunnel syndrome can greatly benefit from preoperative MRI. However, it should be noted that not all cases with tarsal tunnel syndrome have MRI-demonstrable causes.

Evaluation of the Influence Caused by Tunnel Construction on Groundwater Environment: A Case Study of Tongluoshan Tunnel, China

Directory of Open Access Journals (Sweden)

Jian Liu

2015-01-01

Full Text Available Problems related to water inflow during tunnel construction are challenging to designers, workers, and management departments, as they can threaten tunneling project from safety, time, and economic aspects. Identifying the impacts on groundwater environment resulting from tunnel drainage and making a correct assessment before tunnel construction is essential to better understand troubles that would be encountered during tunnel excavation and helpful to adopt appropriate countermeasures to minimize the influences. This study presents an indicator system and quantifies each indicator of Tongluoshan tunnel, which is located in southwest China with a length of 5.2 km and mainly passes through carbonate rocks and sandstones, based on field investigation and related technological reports. Then, an evaluation is made using fuzzy comprehensive assessment method, with a result showing that it had influenced the local groundwater environment at a moderate degree. Information fed back from environmental investigation and hydrologic monitoring carried out during the main construction period proves the evaluation, as the flow of some springs and streams located beside the tunnel route was found experiencing an apparent decline.

Investigation into scanning tunnelling luminescence microscopy

International Nuclear Information System (INIS)

Manson-Smith, S.K.

2001-01-01

This work reports on the development of a scanning tunnelling luminescence (STL) microscope and its application to the study of Ill-nitride semiconductor materials used in the production of light emitting devices. STL microscopy is a technique which uses the high resolution topographic imaging capabilities of the scanning tunnelling microscope (STM) to generate high resolution luminescence images. The STM tunnelling current acts as a highly localised source of electrons (or holes) which generates luminescence in certain materials. Light generated at the STM tunnelling junction is collected concurrently with the height variation of the tunnelling probe as it is scanned across a sample surface, producing simultaneous topographic and luminescence images. Due to the very localised excitation source, high resolution luminescence images can be obtained. Spectroscopic resolution can be obtained by using filters. Additionally, the variation of luminescence intensity with tunnel current and with bias voltage can provide information on recombination processes and material properties. The design and construction of a scanning tunnelling luminescence microscope is described in detail. Operating under ambient conditions, the microscope has several novel features, including a new type of miniature inertial slider-based approach motor, large solid-angle light collection optical arrangement and a tip-height regulation system which requires the minimum of operator input. (author)

Proceedings of the meeting on tunneling reaction and low temperature chemistry, 97 October. Tunneling reaction and quantum medium

Energy Technology Data Exchange (ETDEWEB)

Miyazaki, Tetsuo; Aratono, Yasuyuki; Ichikawa, Tsuneki; Shiotani, Masaru [eds.

1998-02-01

Present report is the proceedings of the 3rd Meeting on Tunneling Reaction and Low Temperature Chemistry held in Oct. 13 and 14, 1997. The main subject of the meeting is `Tunneling Reaction and Quantum Medium`. In the meeting, the physical and chemical phenomena in the liquid helium such as quantum nucleation, spectroscopy of atoms and molecules, and tunneling abstraction reaction of tritium atom were discussed as the main topics as well as the tunneling reactions in the solid hydrogen and organic compounds. Through the meetings held in 1995, 1996, and 1997, the tunneling phenomena proceeding at various temperatures (room temperature to mK) in the wide fields of chemistry, biology, and physics were discussed intensively and the importance of the tunneling phenomena in the science has been getting clear. The 12 of the presented papers are indexed individually. (J.P.N.)

Proceedings of the meeting on tunneling reaction and low temperature chemistry, 97 October. Tunneling reaction and quantum medium

International Nuclear Information System (INIS)

Miyazaki, Tetsuo; Aratono, Yasuyuki; Ichikawa, Tsuneki; Shiotani, Masaru

1998-02-01

Present report is the proceedings of the 3rd Meeting on Tunneling Reaction and Low Temperature Chemistry held in Oct. 13 and 14, 1997. The main subject of the meeting is 'Tunneling Reaction and Quantum Medium'. In the meeting, the physical and chemical phenomena in the liquid helium such as quantum nucleation, spectroscopy of atoms and molecules, and tunneling abstraction reaction of tritium atom were discussed as the main topics as well as the tunneling reactions in the solid hydrogen and organic compounds. Through the meetings held in 1995, 1996, and 1997, the tunneling phenomena proceeding at various temperatures (room temperature to mK) in the wide fields of chemistry, biology, and physics were discussed intensively and the importance of the tunneling phenomena in the science has been getting clear. The 12 of the presented papers are indexed individually. (J.P.N.)

Tunneling anisotropic magnetoresistance in Co/AIOx/Al tunnel junctions with fcc Co (111) electrodes

NARCIS (Netherlands)

Wang, Kai; Tran, T. Lan Ahn; Brinks, Peter; Brinks, P.; Sanderink, Johannes G.M.; Bolhuis, Thijs; van der Wiel, Wilfred Gerard; de Jong, Machiel Pieter

2013-01-01

Tunneling anisotropic magnetoresistance (TAMR) has been characterized in junctions comprised of face-centered cubic (fcc) Co (111) ferromagnetic electrodes grown epitaxially on sapphire substrates, amorphous AlOx tunnel barriers, and nonmagnetic Al counterelectrodes. Large TAMR ratios have been

Mechanical stability of repository tunnels and factors to be considered for determining tunnel spacing

International Nuclear Information System (INIS)

Takeuchi, Kunifumi

1994-01-01

Kristallin-1 organized by Nagra is currently advanced as a synthetic project regarding a high level radioactive waste (HLW) repository in Switzerland. Its host rock is granitic rocks, and the potential siting area is located in northern Switzerland. The objective of this project is to demonstrate the long term safety of a HLW repository under more site-specific conditions than before. As the detailed geological data were investigated, the average size of undisturbed crystalline rock blocks is limited horizontally to about several hundred meter, therefore, the HLW repository area must be divided into several panels to avoid fracture zones. It is necessary to make tunnel spacing as small as possible for the purpose of reasonably designing the entire layout of repository tunnels. The main factors to be considered for determining repository tunnel spacing are listed. Rock mass modeling, rock mass material properties, the analysis model and parameters, the numerical analysis of repository tunnel stability and its main conclusion are reported. The numerical analysis of the temperature distribution in near field was carried out. Tunnel spacing should be set more than 20 m in view of the maximum temperature. (K.I.)

Evaluation of the scratch collapse test for the diagnosis of carpal tunnel syndrome

NARCIS (Netherlands)

Makanji, H. S.; Becker, S. J. E.; Mudgal, C. S.; Jupiter, J. B.; Ring, D.

2014-01-01

This prospective study measured and compared the diagnostic performance characteristics of various clinical signs and physical examination manoeuvres for carpal tunnel syndrome (CTS), including the scratch collapse test. Eighty-eight adult patients that were prescribed electrophysiological testing

Resonance tunneling electron-vibrational spectroscopy of polyoxometalates.

Science.gov (United States)

Dalidchik, F I; Kovalevskii, S A; Balashov, E M

2017-05-21

The tunneling spectra of the ordered monolayer films of decamolybdodicobaltate (DMDC) compounds deposited from aqueous solutions on HOPG were measured by scanning tunnel microscopy in air. The DMDC spectra, as well as the tunneling spectra of other polyoxometalates (POMs), exhibit well-defined negative differential resistances (NDRs). The mechanism of formation of these spectral features was established from the collection of revealed NDR dependences on the external varying parameters and found to be common to all systems exhibiting Wannier-Stark localization. A model of biresonance tunneling was developed to provide an explanation for the totality of experimental data, both the literature and original, on the tunneling POM probing. A variant of the tunneling electron-vibrational POM spectroscopy was proposed allowing the determination of the three basic energy parameters-energy gaps between the occupied and unoccupied states, frequencies of the vibrational transitions accompanying biresonance electron-tunneling processes, and electron-vibrational interaction constants on the monomolecular level.

Current noise in tunnel junctions

Energy Technology Data Exchange (ETDEWEB)

Frey, Moritz; Grabert, Hermann [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Strasse 3, 79104, Freiburg (Germany)

2017-06-15

We study current fluctuations in tunnel junctions driven by a voltage source. The voltage is applied to the tunneling element via an impedance providing an electromagnetic environment of the junction. We use circuit theory to relate the fluctuations of the current flowing in the leads of the junction with the voltage fluctuations generated by the environmental impedance and the fluctuations of the tunneling current. The spectrum of current fluctuations is found to consist of three parts: a term arising from the environmental Johnson-Nyquist noise, a term due to the shot noise of the tunneling current and a third term describing the cross-correlation between these two noise sources. Our phenomenological theory reproduces previous results based on the Hamiltonian model for the dynamical Coulomb blockade and provides a simple understanding of the current fluctuation spectrum in terms of circuit theory and properties of the average current. Specific results are given for a tunnel junction driven through a resonator. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Anomalous Tunnel Magnetoresistance and Spin Transfer Torque in Magnetic Tunnel Junctions with Embedded Nanoparticles

Science.gov (United States)

Useinov, Arthur; Ye, Lin-Xiu; Useinov, Niazbeck; Wu, Te-Ho; Lai, Chih-Huang

2015-01-01

The tunnel magnetoresistance (TMR) in the magnetic tunnel junction (MTJ) with embedded nanoparticles (NPs) was calculated in range of the quantum-ballistic model. The simulation was performed for electron tunneling through the insulating layer with embedded magnetic and non-magnetic NPs within the approach of the double barrier subsystem connected in parallel to the single barrier one. This model can be applied for both MTJs with in-plane magnetization and perpendicular one. We also calculated the in-plane component of the spin transfer torque (STT) versus the applied voltage in MTJs with magnetic NPs and determined that its value can be much larger than in single barrier system (SBS) for the same tunneling thickness. The reported simulation reproduces experimental data of the TMR suppression and peak-like TMR anomalies at low voltages available in leterature. PMID:26681336

Preferences in Sleep Position Correlate With Nighttime Paresthesias in Healthy People Without Carpal Tunnel Syndrome.

Science.gov (United States)

Roth Bettlach, Carrie L; Hasak, Jessica M; Krauss, Emily M; Yu, Jenny L; Skolnick, Gary B; Bodway, Greta N; Kahn, Lorna C; Mackinnon, Susan E

2017-10-01

Carpal tunnel syndrome has been associated with sleep position preferences. The aim of this study is to assess self-reported nocturnal paresthesias and sleeping position in participants with and without carpal tunnel syndrome diagnosis to further clinical knowledge for preventive and therapeutic interventions. A cross-sectional survey study of 396 participants was performed in young adults, healthy volunteers, and a patient population. Participants were surveyed on risk factors for carpal tunnel syndrome, nocturnal paresthesias, and sleep preferences. Binary logistic regression analysis was performed comparing participants with rare and frequent nocturnal paresthesias. Subanalyses for participants without carpal tunnel syndrome under and over 21 years of age were performed on all factors significantly associated with subclinical compression neuropathy in the overall population. Thirty-three percent of the study population experienced nocturnal paresthesias at least weekly. Increased body mass index ( P < .001) and sleeping with the wrist flexed ( P = .030) were associated with a higher frequency of nocturnal paresthesias. Side sleeping was associated with less frequent nocturnal symptoms ( P = .003). In participants without carpal tunnel syndrome, subgroup analysis illustrated a relationship between nocturnal paresthesias and wrist position. In participants with carpal tunnel syndrome, sleeping on the side had a significantly reduced frequency of nocturnal paresthesias. This study illustrates nocturnal paresthesias in people without history of carpal tunnel syndrome including people younger than previously reported. In healthy patients with upper extremity subclinical compression neuropathy, sleep position modification may be a useful intervention to reduce the frequency of nocturnal symptoms prior to developing carpal tunnel syndrome.

A 2D analytical cylindrical gate tunnel FET (CG-TFET) model: impact of shortest tunneling distance

Science.gov (United States)

Dash, S.; Mishra, G. P.

2015-09-01

A 2D analytical tunnel field-effect transistor (FET) potential model with cylindrical gate (CG-TFET) based on the solution of Laplace’s equation is proposed. The band-to-band tunneling (BTBT) current is derived by the help of lateral electric field and the shortest tunneling distance. However, the analysis is extended to obtain the subthreshold swing (SS) and transfer characteristics of the device. The dependency of drain current, SS and transconductance on gate voltage and shortest tunneling distance is discussed. Also, the effect of scaling the gate oxide thickness and the cylindrical body diameter on the electrical parameters of the device is analyzed.

A 2D analytical cylindrical gate tunnel FET (CG-TFET) model: impact of shortest tunneling distance

International Nuclear Information System (INIS)

Dash, S; Mishra, G P

2015-01-01

A 2D analytical tunnel field-effect transistor (FET) potential model with cylindrical gate (CG-TFET) based on the solution of Laplace’s equation is proposed. The band-to-band tunneling (BTBT) current is derived by the help of lateral electric field and the shortest tunneling distance. However, the analysis is extended to obtain the subthreshold swing (SS) and transfer characteristics of the device. The dependency of drain current, SS and transconductance on gate voltage and shortest tunneling distance is discussed. Also, the effect of scaling the gate oxide thickness and the cylindrical body diameter on the electrical parameters of the device is analyzed. (paper)

Managing cancer pain and symptoms of outpatients by rotation to sustained-release hydromorphone: a prospective clinical trial

NARCIS (Netherlands)

Wirz, Stefan; Wartenberg, Hans Christian; Elsen, Christian; Wittmann, Maria; Diederichs, Marta; Nadstawek, Joachim

2006-01-01

PURPOSE: In this prospective clinical trial we examined the technique of opioid rotation to oral sustained-release hydromorphone for controlling pain and symptoms in outpatients with cancer pain. METHODS: Before and after rotation, 50 patients were assessed by Numerical Analog Scales [Numerical

Instabilities in thin tunnel junctions

International Nuclear Information System (INIS)

Konkin, M.K.; Adler, J.G.

1978-01-01

Tunnel junctions prepared for inelastic electron tunneling spectroscopy are often plagued by instabilities in the 0-500-meV range. This paper relates the bias at which the instability occurs to the barrier thickness

[Clinical auxiliary diagnosis value of high frequency ultrasonographic measurements of the thickness of transverse carpal ligaments in carpal tunnel syndrome patients].

Science.gov (United States)

Xu, L; Chen, F M; Wang, L; Zhang, P X; Jiang, X R

2016-04-18

To evaluate the meaning and value of high-frequency ultrasound in the diagnosis of carpal tunnel syndrome (CTS). In this study, 48 patients (unilateral hand) with CTS were analyzed. The thickness of transverse carpal ligaments at the pisiform bone was measured using high-frequency ultrasound. Open carpal tunnel release procedure was performed in the 48 CTS patients, and the thickness of transverse carpal ligaments at the hamate hook bone measured using vernier caliper under direct vision. The accuracy of thickness of transverse carpal ligaments was evaluated using high-frequency ultrasound. high-frequency ultrasound measurement of thickness of transverse carpal ligaments at the hamate hook bone and pisiform bone, and determination of the diagnostic threshold measurement index using receiver operating characteristic (ROC) curve, sensitivity and specificity were performed and the correlation between the thickness of transverse carpal ligaments and nerve conduction study (NCS) analyzed. The thickness of transverse carpal ligaments in the CTS patients were (0.42±0.08) cm (high-frequency ultrasound) and (0.41±0.06) cm (operation) at hamate hook bone, and there was no significant difference between the two ways (t=0.672, P>0.05). The optimal cut-off value of the transverse carpal ligaments at hamate hook bone was 0.385 cm, the sensitivity 0.775, and the specificity 0.788. The optimal cut-off value of the transverse carpal ligaments at the pisiform bone was 0.315 cm, the sensitivity 0.950, and the specificity 1.000. The transverse carpal ligaments thickness and wrist-index finger sensory nerve conduction velocity (SCV), wrist-middle finger SCV showed a negative correlation. High frequency ultrasound measurements of thickness of transverse carpal ligaments is a valuable method for the diagnosis of CTS.

Tunneling time in fluctuating symmetric double wells: Suppression and enhancement of tunneling by spatial symmetry-preserving perturbations

International Nuclear Information System (INIS)

Kar, Susmita; Bhattacharyya, S.P.

2011-01-01

Graphical abstract: Spatial symmetry-preserving sinusoidal fluctuations of symmetric double-well parameters cause enhancement of tunneling at ω ∼ ω 0 while rectified sinusoidal fluctuations suppress it at ω∼(ω 0 )/2 . Research highlights: → Spatial symmetry-preserving sinusoidal and rectified sinusoidal fluctuations of symmetrical double-well parameters have contrasting effects on tunneling. → Sinusoidal fluctuations at frequency ω ∼ ω 0 causes resonance enhancement of tunneling, ω 0 being the 0 + ↔ 1 + transition frequency. → Under rectified sinusoidal fluctuations at a frequency ω∼1/2 ω 0 suppression or coherent destruction of tunneling is observed due to barrier localization. → The observations are explained by energy-gain analysis and analysis of the time-dependent overlap amplitudes. - Abstract: We investigate how tunneling-time gets affected by spatial symmetry preserving fluctuations in the parameters determining the width, barrier height and well-depth of a symmetric double-well potential. Sinusoidal and rectified sinusoidal fluctuations of the well-parameters are shown to have contrasting effects. Significant enhancement of tunneling is noticed when the well-parameters fluctuate sinusoidally with frequency ω ∼ ω 0 while under rectified sinusoidal perturbation, quenching of tunneling takes place at a fluctuation frequency ω∼1/2 ω 0 ,ω 0 , being the frequency of the lowest transition allowed by the fluctuation induced spatial perturbation of even parity. Time-dependent Hellmann-Feynman theorem is invoked to analyze the energy changes induced by fluctuations. It turns out that the enhancement of tunneling in the sinusoidally fluctuating double well at frequency ω ∼ ω 0 is caused by transition to 1 ± levels under the barrier while in the rectified sinusoidal field at ω∼1/2 ω 0 , a two-photon like process suppresses the tunneling by inducing barrier localization.

Tunnelling in Dante's Inferno

Energy Technology Data Exchange (ETDEWEB)

Furuuchi, Kazuyuki [Manipal Centre for Natural Sciences, Manipal University, Dr.T.M.A. Pai Planetarium Building, Madhav Nagar, Manipal, Karnataka 576104 (India); Sperling, Marcus, E-mail: kazuyuki.furuuchi@manipal.edu, E-mail: marcus.sperling@univie.ac.at [Fakultät für Physik, Universität Wien, Boltzmanngasse 5, A-1090 Wien (Austria)

2017-05-01

We study quantum tunnelling in Dante's Inferno model of large field inflation. Such a tunnelling process, which will terminate inflation, becomes problematic if the tunnelling rate is rapid compared to the Hubble time scale at the time of inflation. Consequently, we constrain the parameter space of Dante's Inferno model by demanding a suppressed tunnelling rate during inflation. The constraints are derived and explicit numerical bounds are provided for representative examples. Our considerations are at the level of an effective field theory; hence, the presented constraints have to hold regardless of any UV completion.

Fire safety assessment of tunnel structures

DEFF Research Database (Denmark)

Gkoumas, Konstantinos; Giuliani, Luisa; Petrini, Francesco

2011-01-01

.g. structural and non structural, organizational, human behavior). This is even more truth for the fire safety design of such structures. Fire safety in tunnels is challenging because of the particular environment, bearing in mind also that a fire can occur in different phases of the tunnel’s lifecycle. Plans...... for upgrading fire safety provisions and tunnel management are also important for existing tunnels. In this study, following a brief introduction of issues regarding the above mentioned aspects, the structural performance of a steel rib for a tunnel infrastructure subject to fire is assessed by means...

Tunnelling in Dante's Inferno

International Nuclear Information System (INIS)

Furuuchi, Kazuyuki; Sperling, Marcus

2017-01-01

We study quantum tunnelling in Dante's Inferno model of large field inflation. Such a tunnelling process, which will terminate inflation, becomes problematic if the tunnelling rate is rapid compared to the Hubble time scale at the time of inflation. Consequently, we constrain the parameter space of Dante's Inferno model by demanding a suppressed tunnelling rate during inflation. The constraints are derived and explicit numerical bounds are provided for representative examples. Our considerations are at the level of an effective field theory; hence, the presented constraints have to hold regardless of any UV completion.

Tunneling path toward spintronics

International Nuclear Information System (INIS)

Miao Guoxing; Moodera, Jagadeesh S; Muenzenberg, Markus

2011-01-01

The phenomenon of quantum tunneling, which was discovered almost a century ago, has led to many subsequent discoveries. One such discovery, spin polarized tunneling, was made 40 years ago by Robert Meservey and Paul Tedrow (Tedrow and Meservey 1971 Phys. Rev. Lett. 26 192), and it has resulted in many fundamental observations and opened up an entirely new field of study. Until the mid-1990s, this field developed at a steady, low rate, after which a huge increase in activity suddenly occurred as a result of the unraveling of successful spin tunneling between two ferromagnets. In the past 15 years, several thousands of papers related to spin polarized tunneling and transport have been published, making this topic one of the hottest areas in condensed matter physics from both fundamental science and applications viewpoints. Many review papers and book chapters have been written in the past decade on this subject. This paper is not exhaustive by any means; rather, the emphases are on recent progress, technological developments and informing the reader about the current direction in which this topic is moving.

Utilization of geothermal energy in tunnels driven by tunnel drilling machines; Nutzung von Geothermie in TBM vorgetriebenen Tunneln

Energy Technology Data Exchange (ETDEWEB)

Pralle, Norbert; Franzius, Jan-Niklas [Ed. Zueblin AG, Stuttgart (Germany). Zentrale Technik; Liebel, Volker [Rehau AG und Co, Erlangen (Germany)

2009-07-01

Tunnels are nowadays more and more often constructed by means of tunnel boring machines rather than by conventional tunnel excavation. This is because tunnel boring provides a greater degree of safety for neighbouring structures, especially when it takes place in near-surface unconsolidated rock. However, bored tunnels offer less favourable framework conditions for the exploitation of geothermal energy because they are usually lined with concrete tubbings. Depending on the tunnel's diameter this normally involves rings of 1 to 2 metres width made up of several concrete elements. Adapting this type of design for geothermal energy production requires the use of an absorber piping system which permits coupling between the individual concrete elements while at the same time meeting the strict geometric tolerances required for its installation. A system of this type has been developed in a cooperation between the Rehau AG +Co. and Ed. Zueblin AG (Central Technology Services). These energy tubbings have already been installed in two tunnel structures and have also been examined in laboratory tests. An extensive measurement programme is under preparation which is aimed at gaining insights for the further optimisation of energy tubbings.

Tunneling anisotropic magnetoresistance driven by magnetic phase transition.

Science.gov (United States)

Chen, X Z; Feng, J F; Wang, Z C; Zhang, J; Zhong, X Y; Song, C; Jin, L; Zhang, B; Li, F; Jiang, M; Tan, Y Z; Zhou, X J; Shi, G Y; Zhou, X F; Han, X D; Mao, S C; Chen, Y H; Han, X F; Pan, F

2017-09-06

The independent control of two magnetic electrodes and spin-coherent transport in magnetic tunnel junctions are strictly required for tunneling magnetoresistance, while junctions with only one ferromagnetic electrode exhibit tunneling anisotropic magnetoresistance dependent on the anisotropic density of states with no room temperature performance so far. Here, we report an alternative approach to obtaining tunneling anisotropic magnetoresistance in α'-FeRh-based junctions driven by the magnetic phase transition of α'-FeRh and resultantly large variation of the density of states in the vicinity of MgO tunneling barrier, referred to as phase transition tunneling anisotropic magnetoresistance. The junctions with only one α'-FeRh magnetic electrode show a magnetoresistance ratio up to 20% at room temperature. Both the polarity and magnitude of the phase transition tunneling anisotropic magnetoresistance can be modulated by interfacial engineering at the α'-FeRh/MgO interface. Besides the fundamental significance, our finding might add a different dimension to magnetic random access memory and antiferromagnet spintronics.Tunneling anisotropic magnetoresistance is promising for next generation memory devices but limited by the low efficiency and functioning temperature. Here the authors achieved 20% tunneling anisotropic magnetoresistance at room temperature in magnetic tunnel junctions with one α'-FeRh magnetic electrode.

Comparison of symptoms, physical examination and electromyography findings, with the results of surgery of carpal tunnel release, in patients treated between January 2007 and December 2008, at the Hospital Calderon Guardia

International Nuclear Information System (INIS)

Chavarria Alvarado, Manuel

2010-01-01

A comparison of the preoperative findings was performed in patients with the diagnosis of carpal tunnel syndrome, with functional outcomes and postoperative residual pain, using the scale Patient Rate Wrist Evaluation (PRWE). All patients have had clinical history, physical examination and electromyography studies. They were operated by minimally invasive open surgery. The information was collected in an Excel table and patients have located via telephone. 100% of the evaluated patients have engaged in activities that involve trauma or repetitive wrist movements. The physical sign with predicative positive value for suspect of carpal tunnel syndrome has been the Phalen, present in over 70% of cases. The amount of physical signs present preoperatively and postoperative results were found without correlation. The mixed lesion, both sensory and motor has been the most found in electrodiagnostic studies. Patients whose studies have been negative, postoperative results have showed less favorable. Only 69% of patients operated in the orthopedic service of the Hospital Rafael Angel Calderon Guardia (HCG), have had favorable postoperative results. (author) [es

Electron tunneling in chemistry

International Nuclear Information System (INIS)

Zamaraev, K.I.; Khajrutdinov, R.F.; Zhdanov, V.P.; Molin, Yu.N.

1985-01-01

Results of experimental and theoretical investigations are outlined systematically on electron tunnelling in chemical reactions. Mechanism of electron transport to great distances is shown to be characteristic to chemical compounds of a wide range. The function of tunnel reactions is discussed for various fields of chemistry, including radiation chemistry, electrochemistry, chemistry of solids, chemistry of surface and catalysis

Signatures of unstable semiclassical trajectories in tunneling

International Nuclear Information System (INIS)

Levkov, D G; Panin, A G; Sibiryakov, S M

2009-01-01

It was found recently that processes of multidimensional tunneling are generally described at high energies by unstable semiclassical trajectories. We study two observational signatures related to the instability of trajectories. First, we find an additional power-law dependence of the tunneling probability on the semiclassical parameter as compared to the standard case of potential tunneling. The second signature is a substantial widening of the probability distribution over final-state quantum numbers. These effects are studied using a modified semiclassical technique which incorporates stabilization of the tunneling trajectories. The technique is derived from first principles. We obtain expressions for the inclusive and exclusive tunneling probabilities in the case of unstable semiclassical trajectories. We also investigate the 'phase transition' between the cases of stable and unstable trajectories across certain 'critical' values of energy. Finally, we derive the relation between the semiclassical probabilities of tunneling from the low-lying and highly excited initial states. This puts on firm ground a conjecture made previously in the semiclassical description of collision-induced tunneling in field theory

Disc Bit Abrasion Parameters in TBM Tunnelling regarded exemplarily for the Gotthard Base Tunnel

Directory of Open Access Journals (Sweden)

Edmund a Wax

2005-11-01

Full Text Available In this article the author presents Amund Bruland’s empirical approach to determine the disc bit abrasion of TBMs (Tunnel Boring Machines, transforms the respective empirical dependencies into approximated mathematical relations and verifies them exemplarily for the currently constructed Gotthard Base Tunnel.

Magnetic reconstruction induced magnetoelectric coupling and spin-dependent tunneling in Ni/KNbO_3/Ni multiferroic tunnel junctions

International Nuclear Information System (INIS)

Zhang, Hu; Dai, Jian-Qing; Song, Yu-Min

2016-01-01

We investigate the magnetoelectric coupling and spin-polarized tunneling in Ni/KNbO_3/Ni multiferroic tunnel junctions with asymmetric interfaces based on density functional theory. The junctions have two stable polarization states. We predict a peculiar magnetoelectric effect in such junctions originating from the magnetic reconstruction of Ni near the KO-terminated interface. This reconstruction is induced by the reversal of the ferroelectric polarization of KNbO_3. Furthermore, the change in the magnetic ordering filters the spin-dependent current. This effect leads to a change in conductance by about two orders of magnitude. As a result we obtain a giant tunneling electroresistance effect. In addition, there exist sizable tunneling magnetoresistance effects for two polarization states. - Highlights: • We study the ME coupling and electron tunneling in Ni/KNbO_3/Ni junctions. • There is magnetic reconstruction of Ni atoms near the KO-terminated interface. • A peculiar magnetoelectric coupling effect is obtained. • Predicted giant tunneling electroresistance effects.

Unified time analysis of photon and particle tunnelling

International Nuclear Information System (INIS)

Olkhovsky, V.S.; Recami, Erasmo; Jakiel, Jacek

2004-01-01

A unified time analysis of photon and nonrelativistic particle tunnellings is presented, in which time is regarded as a quantum observable, canonically conjugated to energy. Within this approach, one can introduce self-consistent definitions of the tunnelling times, on the basis of conventional quantum mechanics (or one-dimensional quantum electrodynamics) only. The validity of the Hartman effect [which states the tunnelling duration to be independent of the (opaque) barrier width, with superluminal group velocities of the tunnelling packet as a consequence] is verified for all the known expressions of the mean tunnelling time. However, some noticeable generalizations of (and deviations from) the Hartman effect are, as well, briefly investigated. Moreover, the analogy between particle and photon tunnelling is suitably exploited; on the basis of such an analogy, an explanation of some recent interesting microwave and optical experimental results on tunnelling times is proposed. Attention is devoted, at last, to some aspects of the causality problem for particle and photon tunnelling

The anisotropic tunneling behavior of spin transport in graphene-based magnetic tunneling junction

Science.gov (United States)

Pan, Mengchun; Li, Peisen; Qiu, Weicheng; Zhao, Jianqiang; Peng, Junping; Hu, Jiafei; Hu, Jinghua; Tian, Wugang; Hu, Yueguo; Chen, Dixiang; Wu, Xuezhong; Xu, Zhongjie; Yuan, Xuefeng

2018-05-01

Due to the theoretical prediction of large tunneling magnetoresistance (TMR), graphene-based magnetic tunneling junction (MTJ) has become an important branch of high-performance spintronics device. In this paper, the non-collinear spin filtering and transport properties of MTJ with the Ni/tri-layer graphene/Ni structure were studied in detail by utilizing the non-equilibrium Green's formalism combined with spin polarized density functional theory. The band structure of Ni-C bonding interface shows that Ni-C atomic hybridization facilitates the electronic structure consistency of graphene and nickel, which results in a perfect spin filtering effect for tri-layer graphene-based MTJ. Furthermore, our theoretical results show that the value of tunneling resistance changes with the relative magnetization angle of two ferromagnetic layers, displaying the anisotropic tunneling behavior of graphene-based MTJ. This originates from the resonant conduction states which are strongly adjusted by the relative magnetization angles. In addition, the perfect spin filtering effect is demonstrated by fitting the anisotropic conductance with the Julliere's model. Our work may serve as guidance for researches and applications of graphene-based spintronics device.

Improved multidimensional semiclassical tunneling theory.

Science.gov (United States)

Wagner, Albert F

2013-12-12

We show that the analytic multidimensional semiclassical tunneling formula of Miller et al. [Miller, W. H.; Hernandez, R.; Handy, N. C.; Jayatilaka, D.; Willets, A. Chem. Phys. Lett. 1990, 172, 62] is qualitatively incorrect for deep tunneling at energies well below the top of the barrier. The origin of this deficiency is that the formula uses an effective barrier weakly related to the true energetics but correctly adjusted to reproduce the harmonic description and anharmonic corrections of the reaction path at the saddle point as determined by second order vibrational perturbation theory. We present an analytic improved semiclassical formula that correctly includes energetic information and allows a qualitatively correct representation of deep tunneling. This is done by constructing a three segment composite Eckart potential that is continuous everywhere in both value and derivative. This composite potential has an analytic barrier penetration integral from which the semiclassical action can be derived and then used to define the semiclassical tunneling probability. The middle segment of the composite potential by itself is superior to the original formula of Miller et al. because it incorporates the asymmetry of the reaction barrier produced by the known reaction exoergicity. Comparison of the semiclassical and exact quantum tunneling probability for the pure Eckart potential suggests a simple threshold multiplicative factor to the improved formula to account for quantum effects very near threshold not represented by semiclassical theory. The deep tunneling limitations of the original formula are echoed in semiclassical high-energy descriptions of bound vibrational states perpendicular to the reaction path at the saddle point. However, typically ab initio energetic information is not available to correct it. The Supporting Information contains a Fortran code, test input, and test output that implements the improved semiclassical tunneling formula.

Superconducting tunnel-junction refrigerator

International Nuclear Information System (INIS)

Melton, R.G.; Paterson, J.L.; Kaplan, S.B.

1980-01-01

The dc current through an S 1 -S 2 tunnel junction, with Δ 2 greater than Δ 1 , when biased with eV 1 +Δ 2 , will lower the energy in S 1 . This energy reduction will be shared by the phonons and electrons. This device is shown to be analogous to a thermoelectric refrigerator with an effective Peltier coefficient π* approx. Δ 1 /e. Tunneling calculations yield the cooling power P/sub c/, the electrical power P/sub e/ supplied by the bias supply, and the cooling efficiency eta=P/sub c//P/sub e/. The maximum cooling power is obtained for eV= +- (Δ 2 -Δ 1 ) and t 1 =T 1 /T/sub c/1 approx. 0.9. Estimates are made of the temperature difference T 2 -T 1 achievable in Al-Pb and Sn-Pb junctions with an Al 2 O 3 tunneling barrier. The performance of this device is shown to yield a maximum cooling efficiency eta approx. = Δ 1 /(Δ 2 -Δ 1 ) which can be compared with that available in an ideal Carnot refrigerator of eta=T 1 /(T 2 -T 1 ). The development of a useful tunnel-junction refrigerator requires a tunneling barrier with an effective thermal conductance per unit area several orders of magnitude less than that provided by the A1 2 O 3 barrier in the Al-Pb and Sn-Pb systems

TunnelVision: LHC Tunnel Photogrammetry System for Structural Monitoring

CERN Document Server

Fallas, William

2014-01-01

In this document an algorithm to detect deformations in the LHC Tunnel of CERN is presented. It is based on two images, one represents the ideal state of the tunnel and the other one the actual state. To find the differences between both, the algorithm is divided in three steps. First, an image enhancement is applied to make easier the detection. Second, two different approaches to reduce noise are applied to one or both images. And third, it is defined a group of characteristics about the type of deformation desired to detect. Finally, the conclusions show the effectiveness of the algorithm in the experimental results.

Electric and VLF-MT survey of Tegatayama tunnel; Tegatayama tunnel no denki tansa oyobi VLF tansa

Energy Technology Data Exchange (ETDEWEB)

Nishitani, T [Akita University, Akita (Japan). Mining College

1997-05-27

To survey the structure at the depth between 20 and 30 m, field tests were conducted by means of vertical electric and VFL-MT (magnetotelluric) survey. Tegatayama tunnel has a total length of 276 m, width of 7.5 m, and height of 4.7 m, and the depth from the surface is about 28 m near the top of mountain. Near the tunnel, the thickness of surface soil is about 60 cm, which consists of clay soil including soft mudstone gravel. It was found that terrace deposit is distributed up to the depth of 8 m, and that mudstone is distributed below the depth of 8 m. Weighted four-electrode method was adopted for the vertical electrical survey. Measurements were conducted at the immediately above the tunnel, 10 m apart from the center of tunnel in the right and left, and 20 m apart from the center in the east. For the VLF-MT method, component of frequency 22.2 kHz was used. As a result of the tests, it was difficult to illustrate the existence of tunnel from the vertical electrical survey only at one point. Feature of the tunnel could be well illustrated by means of the VLF-MT method. 3 refs., 9 figs.

Characterization of the influence of building a road on the stability of the tunnel lining in a Banska Bystrica railway tunnel

Directory of Open Access Journals (Sweden)

Vavrek Pavol

2001-06-01

Full Text Available This paper deals with solving the problem of tunnel lining stability in a railway tunnel. The road cut was made into the overburden of the tunnel. I investigated the effect of the road cut on the stability of tunnel lining. The FLAC3D mathematical modelling technique was used for this purpose. The solution consist of: - - - - - - - - - - - -modelling the initial situation before building the intervention,Determing the internal characteristics of the tunnel lining in its original state,modelling the situation after making the road cut,Determing the internal characteristics of the tunnel lining after the building intervention,Comparison of the internal characteristics of the tunnel lining before and after the building intervention.In the model, I used these general geotechnical properties of the rock environment and the tunnel lining:Material Youngus modulus [MPa] Poissons RatioClay 8 0,42Weakly wheathered calcite 3 000 0,25Hard wheathered calcite 600 0,30Fill 300 0,25Lining 20 000 0,20The arbitration of the tunnel lining stability was executed on the basis of the Mohr – Coulomb limit of the state. Building the road cut does not lead to loss of stability in the tunnel a at Station 1.225 00 or at Station 1.300 00.

Electron tunneling in proteins program.

Science.gov (United States)

Hagras, Muhammad A; Stuchebrukhov, Alexei A

2016-06-05

We developed a unique integrated software package (called Electron Tunneling in Proteins Program or ETP) which provides an environment with different capabilities such as tunneling current calculation, semi-empirical quantum mechanical calculation, and molecular modeling simulation for calculation and analysis of electron transfer reactions in proteins. ETP program is developed as a cross-platform client-server program in which all the different calculations are conducted at the server side while only the client terminal displays the resulting calculation outputs in the different supported representations. ETP program is integrated with a set of well-known computational software packages including Gaussian, BALLVIEW, Dowser, pKip, and APBS. In addition, ETP program supports various visualization methods for the tunneling calculation results that assist in a more comprehensive understanding of the tunneling process. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Tunneling Anomalous and Spin Hall Effects.

Science.gov (United States)

Matos-Abiague, A; Fabian, J

2015-07-31

We predict, theoretically, the existence of the anomalous Hall effect when a tunneling current flows through a tunnel junction in which only one of the electrodes is magnetic. The interfacial spin-orbit coupling present in the barrier region induces a spin-dependent momentum filtering in the directions perpendicular to the tunneling current, resulting in a skew tunneling even in the absence of impurities. This produces an anomalous Hall conductance and spin Hall currents in the nonmagnetic electrode when a bias voltage is applied across the tunneling heterojunction. If the barrier is composed of a noncentrosymmetric material, the anomalous Hall conductance and spin Hall currents become anisotropic with respect to both the magnetization and crystallographic directions, allowing us to separate this interfacial phenomenon from the bulk anomalous and spin Hall contributions. The proposed effect should be useful for proving and quantifying the interfacial spin-orbit fields in metallic and metal-semiconductor systems.

Relativistic tunneling through two successive barriers

International Nuclear Information System (INIS)

Lunardi, Jose T.; Manzoni, Luiz A.

2007-01-01

We study the relativistic quantum mechanical problem of a Dirac particle tunneling through two successive electrostatic barriers. Our aim is to study the emergence of the so-called generalized Hartman effect, an effect observed in the context of nonrelativistic tunneling as well as in its counterparts and which is often associated with the possibility of superluminal velocities in the tunneling process. We discuss the behavior of both the phase (or group) tunneling time and the dwell time, and show that in the limit of opaque barriers the relativistic theory also allows the emergence of the generalized Hartman effect. We compare our results with the nonrelativistic ones and discuss their interpretation

Thermodynamics of phonon-modulated tunneling centers

International Nuclear Information System (INIS)

Junker, W.; Wagner, M.

1989-01-01

In recent years tunneling centers have frequently been used to explain the unusual thermodynamic properties of disordered materials; in these approaches, however, the effect of the tunneling-phonon interaction is neglected. The present study considers the archetype model of phono-assisted tunneling, which is well known from other areas of tunneling physics (quantum diffusion, etc.). It is shown that the full thermodynamic information can be rigorously extracted from a single Green function. An extended factorization procedure beyond Hartree-Fock is introduced, which is checked by sum rules as well as by exact Goldberger-Adams expansions. The phonon-modulated internal energy and specific heat are calculated for different power-law coupling setups

Characterization of magnetic tunnel junction test pads

DEFF Research Database (Denmark)

Østerberg, Frederik Westergaard; Kjær, Daniel; Nielsen, Peter Folmer

2015-01-01

We show experimentally as well as theoretically that patterned magnetic tunnel junctions can be characterized using the current-in-plane tunneling (CIPT) method, and the key parameters, the resistance-area product (RA) and the tunnel magnetoresistance (TMR), can be determined. The CIPT method...

A Case Report of Carpal Tunnel Syndrome with Raynaud's Phenomenon Treated by Bee Venom and Carthami Flos Pharmacopuncture

Directory of Open Access Journals (Sweden)

Choi Seok-woo

2009-03-01

Full Text Available Objectives : This study is to report the effect of Pharmacopuncture therapy on a patient suffering from the pain and cold intolerance of hand caused by Carpal tunnel syndrome with Raynaud's phenomenon. Methods : We had treated the patient diagnosed as Carpal tunnel syndrome with Raynaud's phenomenon by Sweet BV and CF pharmacopuncture. We injected Sweet BV and CF into acupuncture points on both hands - Sweet BV into Baxie (EX-UE9, CF into Naegwan (PC6 and Daereung (PC7.And then we evaluated her symptoms by VAS (Visual Analog Scale. Results : Clinical symptoms about Carpal tunnel syndrome with Raynaud's phenomenon were remarkably improved by Sweet BV and CF Pharmacopuncture. Conclusion : Therefore, we concluded that pharmacopuncture therapy - Sweet BV, CF etc. - may be useful to treat Carpal tunnel syndrome with Raynaud's phenomenon.

Double incision iso-anatomical ACL reconstruction: the freedom to place the femoral tunnel within the anatomical attachment site without exception.

Science.gov (United States)

Arnold, Markus P; Duthon, Victoria; Neyret, Philippe; Hirschmann, Michael T

2013-02-01

The present paper describes the rationale behind the surgical technique and the clinical results of the iso-anatomical, single bundle bone patellar-tendon bone anterior cruciate ligament (ACL) reconstruction. Using a second incision on the distal lateral femur an outside-in femoral tunnel is drilled. Guided by a special aiming device it is possible to place the femoral tunnel in the centre of the ACL footprint in every single case. Since every crucial step of the procedure is under visual control, the technique is safe and reliable, which is mirrored by good clinical results.

Franck-Condon fingerprinting of vibration-tunneling spectra.

Science.gov (United States)

Berrios, Eduardo; Sundaradevan, Praveen; Gruebele, Martin

2013-08-15

We introduce Franck-Condon fingerprinting as a method for assigning complex vibration-tunneling spectra. The B̃ state of thiophosgene (SCCl2) serves as our prototype. Despite several attempts, assignment of its excitation spectrum has proved difficult because of near-degenerate vibrational frequencies, Fermi resonance between the C-Cl stretching mode and the Cl-C-Cl bending mode, and large tunneling splittings due to the out-of-plane umbrella mode. Hence, the spectrum has never been fitted to an effective Hamiltonian. Our assignment approach replaces precise frequency information with intensity information, eliminating the need for double resonance spectroscopy or combination differences, neither of which have yielded a full assignment thus far. The dispersed fluorescence spectrum of each unknown vibration-tunneling state images its character onto known vibrational progressions in the ground state. By using this Franck-Condon fingerprint, we were able to determine the predominant character of several vibration-tunneling states and assign them; in other cases, the fingerprinting revealed that the states are strongly mixed and cannot be characterized with a simple normal mode assignment. The assigned transitions from vibration-tunneling wave functions that were not too strongly mixed could be fitted within measurement uncertainty by an effective vibration-tunneling Hamiltonian. A fit of all observed vibration-tunneling states will require a full resonance-tunneling Hamiltonian.

Hawking temperature from tunnelling formalism

OpenAIRE

Mitra, P.

2007-01-01

It has recently been suggested that the attempt to understand Hawking radiation as tunnelling across black hole horizons produces a Hawking temperature double the standard value. It is explained here how one can obtain the standard value in the same tunnelling approach.

Homoepitaxial graphene tunnel barriers for spin transport

Directory of Open Access Journals (Sweden)

Adam L. Friedman

2016-05-01

Full Text Available Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. Here, we demonstrate that hydrogenation or fluorination of graphene can be used to create a tunnel barrier. We demonstrate successful tunneling by measuring non-linear IV curves and a weakly temperature dependent zero-bias resistance. We demonstrate lateral transport of spin currents in non-local spin-valve structures, and determine spin lifetimes with the non-local Hanle effect. We compare the results for hydrogenated and fluorinated tunnel and we discuss the possibility that ferromagnetic moments in the hydrogenated graphene tunnel barrier affect the spin transport of our devices.

Homoepitaxial graphene tunnel barriers for spin transport

Science.gov (United States)

Friedman, Adam L.; van't Erve, Olaf M. J.; Robinson, Jeremy T.; Whitener, Keith E.; Jonker, Berend T.

2016-05-01

Tunnel barriers are key elements for both charge-and spin-based electronics, offering devices with reduced power consumption and new paradigms for information processing. Such devices require mating dissimilar materials, raising issues of heteroepitaxy, interface stability, and electronic states that severely complicate fabrication and compromise performance. Graphene is the perfect tunnel barrier. It is an insulator out-of-plane, possesses a defect-free, linear habit, and is impervious to interdiffusion. Nonetheless, true tunneling between two stacked graphene layers is not possible in environmental conditions usable for electronics applications. However, two stacked graphene layers can be decoupled using chemical functionalization. Here, we demonstrate that hydrogenation or fluorination of graphene can be used to create a tunnel barrier. We demonstrate successful tunneling by measuring non-linear IV curves and a weakly temperature dependent zero-bias resistance. We demonstrate lateral transport of spin currents in non-local spin-valve structures, and determine spin lifetimes with the non-local Hanle effect. We compare the results for hydrogenated and fluorinated tunnel and we discuss the possibility that ferromagnetic moments in the hydrogenated graphene tunnel barrier affect the spin transport of our devices.

Does flexible tunnel drilling affect the femoral tunnel angle measurement after anterior cruciate ligament reconstruction?

NARCIS (Netherlands)

Muller, Bart; Hofbauer, Marcus; Atte, Akere; van Dijk, C. Niek; Fu, Freddie H.

2015-01-01

To quantify the mean difference in femoral tunnel angle (FTA) as measured on knee radiographs between rigid and flexible tunnel drilling after anatomic anterior cruciate ligament (ACL) reconstruction. Fifty consecutive patients that underwent primary anatomic ACL reconstruction with a single femoral

Air supersaturation, release of wooden fibres and upstream migration of Atlantic salmon at Rygene power plant in the River Nidelva, Aust Agder county

International Nuclear Information System (INIS)

Thorstad, Eva B.; Kroglund, Frode; Oekland, Finn; Heggberget, Tor G.

1997-01-01

Incidents of dead fish have been reported in connection with a power plant at Rygene on the River Nidelva in the Aust-Agder county, Norway. Air supersaturation has been used in a bypass construction of the power plant tunnel system. In addition, wooden fibres from a fabric have been released into the water of the tunnel. Results from relevant studies concerning air saturation, wooden fibres and upstream migration are summarised in this report. 148 refs., 4 figs., 2 tabs

A review on all-perovskite multiferroic tunnel junctions

Directory of Open Access Journals (Sweden)

Yuewei Yin

2017-12-01

Full Text Available Although the basic concept was proposed only about 10 years ago, multiferroic tunnel junctions (MFTJs with a ferroelectric barrier sandwiched between two ferromagnetic electrodes have already drawn considerable interests, driven mainly by its potential applications in multi-level memories and electric field controlled spintronics. The purpose of this article is to review the recent progress of all-perovskite MFTJs. Starting from the key functional properties of the tunneling magnetoresistance, tunneling electroresistance, and tunneling electromagnetoresistance effects, we discuss the main origins of the tunneling electroresistance effect, recent progress in achieving multilevel resistance states in a single device, and the electrical control of spin polarization and transport through the ferroelectric polarization reversal of the tunneling barrier.

Unified time analysis of photon and particle tunnelling

International Nuclear Information System (INIS)

Olkhovsky, Vladislav S.; Recami, Erasmo; Jakiel, Jacek

2001-07-01

A unified approach to the time analysis of tunnelling of nonrelativistic particles is presented, in which Time is regarded as a quantum-mechanical observable, canonically conjugated to Energy. The validity of the Hartman effect (independence of the Tunnelling Time of the opaque barrier width, with superluminal group velocities as a consequence) is verified for all the known expressions of the mean tunnelling time. Moreover, the analogy between particle and photon tunnelling is suitably exploited. On the basic of such an analogy, an explanation of some recent microwave and optics experimental results on tunnelling time is proposed. Attention is devoted to some aspects of the causality problem for particle and photon tunnelling. (author)

Time evolution of tunneling in a thermal medium: Environment-driven excited tunneling

International Nuclear Information System (INIS)

Matsumoto, Sh.; Yoshimura, M.

2004-01-01

Time evolution of tunneling phenomena proceeding in a thermal medium is studied using a standard model of environmental interaction. A semiclassical probability formula for the particle motion in a metastable state of a one-dimensional system put in a thermal medium is combined with the formula of the quantum penetration factor through a potential barrier to derive the tunneling rate in the medium. The effect of environment, its influence on time evolution in particular, is clarified in our real-time formalism. A nonlinear resonance effect is shown to enhance the tunneling rate at finite times of order 2/η, with η the friction coefficient unless η is too small. In the linear approximation this effect has relevance to the parametric resonance. This effect enhances the possibility of early termination of the cosmological phase transition much prior to the typical Hubble time

Quantum Electron Tunneling in Respiratory Complex I1

Science.gov (United States)

Hayashi, Tomoyuki; Stuchebrukhov, Alexei A.

2014-01-01

We have simulated the atomistic details of electronic wiring of all Fe/S clusters in complex I, a key enzyme in the respiratory electron transport chain. The tunneling current theory of many-electron systems is applied to the broken-symmetry (BS) states of the protein at the ZINDO level. One-electron tunneling approximation is found to hold in electron tunneling between the anti-ferromagnetic binuclear and tetranuclear Fe/S clusters with moderate induced polarization of the core electrons. Calculated tunneling energy is about 3 eV higher than Fermi level in the band gap of the protein, which supports that the mechanism of electron transfer is quantum mechanical tunneling, as in the rest of electron transport chain. Resulting electron tunneling pathways consist of up to three key contributing protein residues between neighboring Fe/S clusters. A distinct signature of the wave properties of electrons is observed as quantum interferences when multiple tunneling pathways exist. In N6a-N6b, electron tunnels along different pathways depending on the involved BS states, suggesting possible fluctuations of the tunneling pathways driven by the local protein environment. The calculated distance dependence of the electron transfer rates with internal water molecules included are in good agreement with a reported phenomenological relation. PMID:21495666

Development of the safety control framework for shield tunneling in close proximity to the operational subway tunnels: case studies in mainland China.

Science.gov (United States)

Li, Xinggao; Yuan, Dajun

2016-01-01

China's largest cities like Beijing and Shanghai have seen a sharp increase in subway network development as a result of the rapid urbanization in the last decade. The cities are still expanding their subway networks now, and many shield tunnels are being or will be constructed in close proximity to the existing operational subway tunnels. The execution plans for the new nearby shield tunnel construction calls for the development of a safety control framework-a set of control standards and best practices to help organizations manage the risks involved. Typical case studies and relevant key technical parameters are presented with a view to presenting the resulting safety control framework. The framework, created through collaboration among the relevant parties, addresses and manages the risks in a systematic way based on actual conditions of each tunnel crossing construction. The framework consists of six parts: (1) inspecting the operational subway tunnels; (2) deciding allowed movements of the existing tunnels and tracks; (3) simulating effects of the shield tunneling on the existing tunnels; (4) doing preparation work; (5) monitoring design and information management; and (6) measures and activation mechanism of the countermeasures. The six components are explained and demonstrated in detail. In the end, discussions made involve construction and post-construction settlement of the operational tunnel, application of the remedial grouting to rectify excessive settlements of the operational tunnel, and use of the innovative tool of the optical fiber measurement for tunnel movement monitoring. It is concluded that the construction movement of the tunnel can be controlled within 15 mm when the shield machine is <7 m in excavation diameter. The post-construction settlement of the tunnel buried in the very soft ground is much greater than its construction settlement, and last several years until reaching a final stable state. Two cases are outlined to demonstrate the

Time-resolved scanning tunnelling microscopy

NARCIS (Netherlands)

van Houselt, Arie; Zandvliet, Henricus J.W.

2010-01-01

Scanning tunneling microscopy has revolutionized our ability to image, study, and manipulate solid surfaces on the size scale of atoms. One important limitation of the scanning tunneling microscope (STM) is, however, its poor time resolution. Recording a standard image with a STM typically takes

Apparent tunneling in chemical reactions

DEFF Research Database (Denmark)

Henriksen, Niels Engholm; Hansen, Flemming Yssing; Billing, G. D.

2000-01-01

A necessary condition for tunneling in a chemical reaction is that the probability of crossing a barrier is non-zero, when the energy of the reactants is below the potential energy of the barrier. Due to the non-classical nature (i.e, momentum uncertainty) of vibrational states this is, however......, not a sufficient condition in order to establish genuine tunneling as a result of quantum dynamics. This proposition is illustrated for a two-dimensional model potential describing dissociative sticking of N-2 on Ru(s). It is suggested that the remarkable heavy atom tunneling, found in this system, is related...

Quantum dot resonant tunneling diode single photon detector with aluminum oxide aperture defined tunneling area

DEFF Research Database (Denmark)

Li, H.W.; Kardynal, Beata; Ellis, D.J.P.

2008-01-01

Quantum dot resonant tunneling diode single photon detector with independently defined absorption and sensing areas is demonstrated. The device, in which the tunneling is constricted to an aperture in an insulating layer in the emitter, shows electrical characteristics typical of high quality res...

Unidirectional magnetoelectric-field multiresonant tunneling

International Nuclear Information System (INIS)

Kamenetskii, E O; Hollander, E; Joffe, R; Shavit, R

2015-01-01

Unidirectional multi-resonant tunneling of the magnetoelectric (ME) field excitations through a subwavelength (regarding the scales of regular electromagnetic radiation) vacuum or isotropic-dielectric regions has been observed in two-port microwave structures having a quasi-2D ferrite disk with magnetic dipolar mode (MDM) oscillations. The excitations manifest themselves as Fano-resonance peaks in the scattering-matrix parameters at the stationary states of the MDM spectrum. The ME near-field excitations are quasimagnetostatic fields ∇-vector × H-vector =0 with non-zero helicity parameter: F=(1/(16π))Im{ E-vector ⋅( ∇-vector × E-vector ) ∗ }. Topological phase properties of ME fields are determined by edge chiral currents of MDM oscillations. We show that while for a given direction of a bias magnetic field (in other words, for a given direction of time), the ME field excitations are considered as ‘forward’ tunneling processes, in the opposite direction of a bias magnetic field (the opposite direction of time), there are ‘backward’ tunneling processes. Unidirectional ME field resonant tunneling is observed due to the distinguishable topology of the ‘forward’ and ‘backward’ ME field excitations. We establish a close connection between the Fano-resonance unidirectional tunneling and the topology of the ME fields in different microwave structures. (paper)

MR imaging of the carpal tunnel syndrome

International Nuclear Information System (INIS)

Elias, D.; Lind, J.; Blair, S.; Light, T.; Wisniewski, R.; Moncado, R.

1987-01-01

MR is an ideal noninvasive means to image the structures forming the carpal tunnel in both normal and pathologic conditions. The carpal tunnel syndrome is a frequently encountered entity caused by compression of the median nerve as it passes through the carpal tunnel. This may result from a variety of conditions including edema from acute chronic trauma, rheumatoid tenosynovitis, degenerative joint disease or soft-tissue masses. This exhibit demonstrates the optimal MR imaging techniques to display the structures of the carpal tunnel. The normal anatomy is reviewed and variations in normal anatomy that may predispose to disease are included. Examples of the morphologic changes demonstrated in 20 patients diagnosed with carpal tunnel syndrome are displayed. The exhibit also reviews the findings in 20 postoperative cases

Concept development for HLW disposal research tunnel

International Nuclear Information System (INIS)

Queon, S. K.; Kim, K. S.; Park, J. H.; Jeo, W. J.; Han, P. S.

2003-01-01

In order to dispose high-level radioactive waste in a geological formation, it is necessary to assess the safety of a disposal concept by excavating a research tunnel in the same geological formation as the host rock mass. The design concept of a research tunnel depends on the actual disposal concept, repository geometry, experiments to be carried at the tunnel, and geological conditions. In this study, analysis of the characteristics of the disposal research tunnel, which is planned to be constructed at KAERI site, calculation of the influence of basting impact on neighbor facilities, and computer simuation for mechanical stability analysis using a three-dimensional code, FLAC3D, had been carried out to develop the design concept of the research tunnel

Seismic Response of Tunnel Lining for Shallow-Bias Tunnel with a Small Clear Distance under Wenchuan Earthquake

Directory of Open Access Journals (Sweden)

Yang Hui

2018-01-01

Full Text Available In order to study the internal force characteristics of shallow-bias tunnel with a small clear distance in earthquake, a large-scale shaking table slope model test was designed, and the geometric scale was 1 : 10. In the model test, the Wenchuan (WC seismic wave was used as the excitation wave. Then, the three-dimensional numerical model was established by using MIDAS-NX, and the reliability of the numerical model was verified by comparing the acceleration of the test results. The axial force, bending moment, and shear force of the tunnel cross section and longitudinal direction were calculated by the numerical model under different excitation directions included the horizontal direction (X, the vertical direction (Z, and the horizontal and vertical direction (XZ. The results show the following. (1 The internal force of right arch foot of left hole and the left arch foot of right hole is larger than other part of the tunnels because the distance between the two tunnels is smaller and they interact with each other. (2 The loading direction of single direction loading method is different and the variation trend of tunnel force are different, so the loading direction of seismic wave has a significant influence on the seismic force response of the tunnel. (3 All of the internal force values of tunnel lining under the seismic wave action in bidirection are larger than those in single direction. The value is not a simple superposition of two directions and has some coupling effect. The influence of the vertical seismic wave cannot be ignored in dynamic response research. These results improve the understanding of the rock slope with small spacing tunnel under seismic action.

Seepage into PEP tunnel

International Nuclear Information System (INIS)

Weidner, H.

1990-01-01

The current rate of seepage into the PEP tunnel in the vicinity of IR-10 is very low compared to previous years. Adequate means of handling this low flow are in place. It is not clear whether the reduction in the flow is temporary, perhaps due to three consecutive dry years, or permanent due to drainage of a perched water table. During PEP construction a large amount of effort was expended in attempts to seal the tunnel, with no immediate effect. The efforts to ''manage'' the water flow are deemed to be successful. By covering equipment to protect it from dripping water and channeling seepage into the drainage gutters, the seepage has been reduced to a tolerable nuisance. There is no sure, safe procedure for sealing a leaky shotcreted tunnel

Tunneling Plasmonics in Bilayer Graphene.

Science.gov (United States)

Fei, Z; Iwinski, E G; Ni, G X; Zhang, L M; Bao, W; Rodin, A S; Lee, Y; Wagner, M; Liu, M K; Dai, S; Goldflam, M D; Thiemens, M; Keilmann, F; Lau, C N; Castro-Neto, A H; Fogler, M M; Basov, D N

2015-08-12

We report experimental signatures of plasmonic effects due to electron tunneling between adjacent graphene layers. At subnanometer separation, such layers can form either a strongly coupled bilayer graphene with a Bernal stacking or a weakly coupled double-layer graphene with a random stacking order. Effects due to interlayer tunneling dominate in the former case but are negligible in the latter. We found through infrared nanoimaging that bilayer graphene supports plasmons with a higher degree of confinement compared to single- and double-layer graphene, a direct consequence of interlayer tunneling. Moreover, we were able to shut off plasmons in bilayer graphene through gating within a wide voltage range. Theoretical modeling indicates that such a plasmon-off region is directly linked to a gapped insulating state of bilayer graphene, yet another implication of interlayer tunneling. Our work uncovers essential plasmonic properties in bilayer graphene and suggests a possibility to achieve novel plasmonic functionalities in graphene few-layers.

The Ribosomal Protein uL22 Modulates the Shape of the Protein Exit Tunnel

DEFF Research Database (Denmark)

Wekselman, Itai; Zimmerman, Ella; Davidovich, Chen

2017-01-01

Erythromycin is a clinically useful antibiotic that binds to an rRNA pocket in the ribosomal exit tunnel. Commonly, resistance to erythromycin is acquired by alterations of rRNA nucleotides that interact with the drug. Mutations in the β hairpin of ribosomal protein uL22, which is rather distal...... of the β hairpin of the mutated uL22 toward the interior of the exit tunnel, triggering a cascade of structural alterations of rRNA nucleotides that propagate to the erythromycin binding pocket. Our findings support recent studies showing that the interactions between uL22 and specific sequences within...

Tunneling with dissipation in open quantum systems

International Nuclear Information System (INIS)

Adamyan, G.G.; Antonenko, N.V.; Scheid, W.

1997-01-01

Based on the general form of the master equation for open quantum systems the tunneling is considered. Using the path integral technique a simple closed form expression for the tunneling rate through a parabolic barrier is obtained. The tunneling in the open quantum systems strongly depends on the coupling with environment. We found the cases when the dissipation prohibits tunneling through the barrier but decreases the crossing of the barrier for the energies above the barrier. As a particular application, the case of decay from the metastable state is considered

Femtosecond tunneling response of surface plasmon polaritons

DEFF Research Database (Denmark)

Keil, Ulrich Dieter Felix; Ha, Taekjip; Jensen, Jacob Riis

1998-01-01

We obtain femtosecond (200 fs) time resolution using a scanning tunneling microscope on surface plasmon polaritons (SPPs) generated by two 100 fs laser beams in total internal reflection geometry. The tunneling gap dependence of the signal clearly indicates the tunneling origin of the signal...... and suggests that nanometer spatial resolution can be obtained together with femtosecond temporal resolution. This fast response, in contrast to the picosecond decay time of SPPs revealed by differential reflectivity measurements, can be attributed to a coherent superposition of SPPs rectified at the tunneling...

Analysis of different tunneling mechanisms of InxGa1−xAs/AlGaAs tunnel junction light-emitting transistors

International Nuclear Information System (INIS)

Wu, Cheng-Han; Wu, Chao-Hsin

2014-01-01

The electrical and optical characteristics of tunnel junction light-emitting transistors (TJLETs) with different indium mole fractions (x = 5% and 2.5%) of the In x Ga 1−x As base-collector tunnel junctions have been investigated. Two electron tunneling mechanisms (photon-assisted or direct tunneling) provide additional currents to electrical output and resupply holes back to the base region, resulting in the upward slope of I-V curves and enhanced optical output under forward-active operation. The larger direct tunneling probability and stronger Franz-Keldysh absorption for 5% TJLET lead to higher collector current slope and less optical intensity enhancement when base-collector junction is under reverse-biased.

Experimental Evidence for Wigner’s Tunneling Time

Science.gov (United States)

Camus, N.; Yakaboylu, E.; Fechner, L.; Klaiber, M.; Laux, M.; Mi, Y.; Hatsagortsyan, K. Z.; Pfeifer, T.; Keitel, C. H.; Moshammer, R.

2018-04-01

Tunneling of a particle through a barrier is one of the counter-intuitive properties of quantum mechanical motion. Thanks to advances in the generation of strong laser fields, new opportunities to dynamically investigate this process have been developed. In the so-called attoclock measurements the electron’s properties after tunneling are mapped on its emission direction. We investigate the tunneling dynamics and achieve a high sensitivity thanks to two refinements of the attoclock principle. Using near-IR wavelength we place firmly the ionization process in the tunneling regime. Furthermore, we compare the electron momentum distributions of two atomic species of slightly different atomic potentials (argon and krypton) being ionized under absolutely identical conditions. Experimentally, using a reaction microscope, we succeed in measuring the 3D electron momentum distributions for both targets simultaneously. Theoretically, the time resolved description of tunneling in strong-field ionization is studied using the leading quantum-mechanical Wigner treatment. A detailed analysis of the most probable photoelectron emission for Ar and Kr allows testing the theoretical models and a sensitive check of the electron initial conditions at the tunnel exit. The agreement between experiment and theory provides a clear evidence for a non-zero tunneling time delay and a non-vanishing longitudinal momentum at this point.

Maximum Smoke Temperature in Non-Smoke Model Evacuation Region for Semi-Transverse Tunnel Fire

OpenAIRE

B. Lou; Y. Qiu; X. Long

2017-01-01

Smoke temperature distribution in non-smoke evacuation under different mechanical smoke exhaust rates of semi-transverse tunnel fire were studied by FDS numerical simulation in this paper. The effect of fire heat release rate (10MW 20MW and 30MW) and exhaust rate (from 0 to 160m3/s) on the maximum smoke temperature in non-smoke evacuation region was discussed. Results show that the maximum smoke temperature in non-smoke evacuation region decreased with smoke exhaust rate. Plug-holing was obse...

Quantum tunneling in the adiabatic Dicke model

International Nuclear Information System (INIS)

Chen Gang; Chen Zidong; Liang Jiuqing

2007-01-01

The Dicke model describes N two-level atoms interacting with a single-mode bosonic field and exhibits a second-order phase transition from the normal to the superradiant phase. The energy levels are not degenerate in the normal phase but have degeneracy in the superradiant phase, where quantum tunneling occurs. By means of the Born-Oppenheimer approximation and the instanton method in quantum field theory, the tunneling splitting, inversely proportional to the tunneling rate for the adiabatic Dicke model, in the superradiant phase can be evaluated explicitly. It is shown that the tunneling splitting vanishes as exp(-N) for large N, whereas for small N it disappears as √(N)/exp(N). The dependence of the tunneling splitting on the relevant parameters, especially on the atom-field coupling strength, is also discussed

Fermion tunneling from higher-dimensional black holes

International Nuclear Information System (INIS)

Lin Kai; Yang Shuzheng

2009-01-01

Via the semiclassical approximation method, we study the 1/2-spin fermion tunneling from a higher-dimensional black hole. In our work, the Dirac equations are transformed into a simple form, and then we simplify the fermion tunneling research to the study of the Hamilton-Jacobi equation in curved space-time. Finally, we get the fermion tunneling rates and the Hawking temperatures at the event horizon of higher-dimensional black holes. We study fermion tunneling of a higher-dimensional Schwarzschild black hole and a higher-dimensional spherically symmetric quintessence black hole. In fact, this method is also applicable to the study of fermion tunneling from four-dimensional or lower-dimensional black holes, and we will take the rainbow-Finsler black hole as an example in order to make the fact explicit.

High Surface Area Tunnels in Hexagonal WO₃.

Science.gov (United States)

Sun, Wanmei; Yeung, Michael T; Lech, Andrew T; Lin, Cheng-Wei; Lee, Chain; Li, Tianqi; Duan, Xiangfeng; Zhou, Jun; Kaner, Richard B

2015-07-08

High surface area in h-WO3 has been verified from the intracrystalline tunnels. This bottom-up approach differs from conventional templating-type methods. The 3.67 Å diameter tunnels are characterized by low-pressure CO2 adsorption isotherms with nonlocal density functional theory fitting, transmission electron microscopy, and thermal gravimetric analysis. These open and rigid tunnels absorb H(+) and Li(+), but not Na(+) in aqueous electrolytes without inducing a phase transformation, accessing both internal and external active sites. Moreover, these tunnel structures demonstrate high specific pseudocapacitance and good stability in an H2SO4 aqueous electrolyte. Thus, the high surface area created from 3.67 Å diameter tunnels in h-WO3 shows potential applications in electrochemical energy storage, selective ion transfer, and selective gas adsorption.

Z-Elongation of the transverse carpal ligament vs. complete resection for the treatment of carpal tunnel syndrome.

Science.gov (United States)

Castro-Menéndez, M; Pagazaurtundúa-Gómez, S; Pena-Paz, S; Huici-Izco, R; Rodríguez-Casas, N; Montero-Viéites, A

Carpal tunnel syndrome is treated successfully by surgical release of the transverse carpal ligament (TCL). However, persistent weakness of grip and pain over the thenar and hypothenar ends of this ligament, and "pillar pain", are reported to be common complications. In order to reduce these complications, different ligament reconstruction or lengthening techniques have been proposed. The purpose of this study is compare effectiveness and complications of TCL z-lengthening technique with complete TCL section. A prospective, randomised, intervention trial was conducted on 80 patients. The patients were divided into 2 groups: 1) complete release of TCL; 2) z-lengthening of TCL according to a modified Simonetta technique. Grip strength, pillar pain and clinical and functional assessment were carried out using the Levine et al. questionnaire. No significant differences were observed (p>.05) in the postoperative reviews between the two groups as regards grip strength loss and pillar pain. There were significant differences between preoperative and postoperative mean Levine scores, but there was no difference in the mean scores of the two procedures at any time. In conclusion, according to the results, TCL z-lengthening is more effective than simple division, but there is no identifiable benefit in z-lengthening for avoiding complications. Copyright © 2016 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Apparatus and method for large tunnel excavation in hard rock

International Nuclear Information System (INIS)

Altseimer, J.H.; Hanold, R.J.

1975-01-01

A tunneling machine is described for producing large tunnels in rock by progressive detachment of the tunnel core by thermal melting a boundary kerf into the tunnel face and simultaneously forming an initial tunnel wall support by deflecting the molten materials against the tunnel walls to provide, when solidified, a continuous liner; and fragmenting the tunnel core circumscribed by the kerf by thermal stress fracturing and in which the heat required for such operations is supplied by a compact nuclear reactor. (U.S.)

Complex use of heat-exchange tunnels

Directory of Open Access Journals (Sweden)

А. Ф. Галкин

2017-04-01

Full Text Available The paper presents separate results of complex research (experimental and theoretical on the application of heat-exchange tunnels – in frozen rocks, among other things – as underground constructions serving two purposes. It is proposed to use heat-exchange tunnels as a separate multi-functional module, which under normal conditions will be used to set standards of heat regime parameters in the mines, and in emergency situations, natural or man-made, will serve as a protective structure to shelter mine workers. Heat-exchange modules can be made from mined-out or specially constructed tunnels. Economic analysis shows that the use of such multi-functional modules does not increase operation and maintenance costs, but enhances safety of mining operations and reliability in case of emergency situations. There are numerous theoretic and experimental investigations in the field of complex use of mining tunnels, which allows to develop regulatory design documents on their basis. Experience of practical application of heat-exchange tunnels has been assessed from the position of regulating heat regime in the mines.

Hoosac tunnel geothermal heat source. Final report

Energy Technology Data Exchange (ETDEWEB)

1982-06-10

The Hoosac Rail Tunnel has been analyzed as a central element in a district heating system for the City of North Adams. The tunnel has been viewed as a collector of the earth's geothermal heat and a seasonal heat storage facility with heat piped to the tunnel in summer from existing facilities at a distance. Heated fluid would be transported in winter from the tunnel to users who would boost the temperature with individual heat pumps. It was concluded the tunnel is a poor source of geothermal heat. The maximum extractable energy is only 2200 million BTU (20000 gallons of oil) at 58/sup 0/F. The tunnel is a poor heat storage facility. The rock conductivity is so high that 75% of the heat injected would escape into the mountain before it could be recaptured for use. A low temperature system, with individual heat pumps for temperature boost could be economically attractive if a low cost fuel (byproduct, solid waste, cogeneration) or a cost effective seasonal heat storage were available.

Tunnelling anisotropic magnetoresistance due to antiferromagnetic CoO tunnel barriers

Science.gov (United States)

Wang, K.; Sanderink, J. G. M.; Bolhuis, T.; van der Wiel, W. G.; de Jong, M. P.

2015-01-01

A new approach in spintronics is based on spin-polarized charge transport phenomena governed by antiferromagnetic (AFM) materials. Recent studies have demonstrated the feasibility of this approach for AFM metals and semiconductors. We report tunneling anisotropic magnetoresistance (TAMR) due to the rotation of antiferromagnetic moments of an insulating CoO layer, incorporated into a tunnel junction consisting of sapphire(substrate)/fcc-Co/CoO/AlOx/Al. The ferromagnetic Co layer is exchange coupled to the AFM CoO layer and drives rotation of the AFM moments in an external magnetic field. The results may help pave the way towards the development of spintronic devices based on AFM insulators. PMID:26486931

Monitoring and Analysis of Ground Settlement Induced by Tunnelling with Slurry Pressure-Balanced Tunnel Boring Machine

Directory of Open Access Journals (Sweden)

Hyunku Park

2018-01-01

Full Text Available A case study of monitoring and analysis of ground settlement caused by tunnelling of stacked twin tunnels for underground metro line construction through the densely populated area using the slurry pressure-balanced TBM is presented. Detailed ground settlement monitoring was carried out for the initial stage of down-track tunnelling in order to estimate trough width factor and volume losses including face, shield, and tail losses. In addition, using the gap model, prediction of volume loss and ground settlement was carried out with consideration of the ground condition, TBM configurations, and actual operation data. The predictions of the gap model were compared with the observed results, and adjustment factors were determined for volume loss estimation. The adjusted factors were applied to predict ground settlement of the up-track tunnel, and its results were compared with the field measurements.

Band-to-band tunneling distance analysis in the heterogate electron–hole bilayer tunnel field-effect transistor

Energy Technology Data Exchange (ETDEWEB)

Padilla, J. L., E-mail: jose.padilladelatorre@epfl.ch [Nanoelectronic Devices Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015 (Switzerland); Departamento de Electrónica y Tecnología de los Computadores, Universidad de Granada, Avda. Fuentenueva s/n, 18071 Granada (Spain); Palomares, A. [Departamento de Matemática Aplicada, Universidad de Granada, Avda. Fuentenueva s/n, 18071 Granada (Spain); Alper, C.; Ionescu, A. M. [Nanoelectronic Devices Laboratory, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015 (Switzerland); Gámiz, F. [Departamento de Electrónica y Tecnología de los Computadores, Universidad de Granada, Avda. Fuentenueva s/n, 18071 Granada (Spain)

2016-01-28

In this work, we analyze the behavior of the band-to-band tunneling distance between electron and hole subbands resulting from field-induced quantum confinement in the heterogate electron–hole bilayer tunnel field-effect transistor. We show that, analogously to the explicit formula for the tunneling distance that can be easily obtained in the semiclassical framework where the conduction and valence band edges are allowed states, an equivalent analytical expression can be derived in the presence of field-induced quantum confinement for describing the dependence of the tunneling distance on the body thickness and material properties of the channel. This explicit expression accounting for quantum confinement holds valid provided that the potential wells for electrons and holes at the top and bottom of the channel can be approximated by triangular profiles. Analytical predictions are compared to simulation results showing very accurate agreement.

Perpendicular magnetic tunnel junction with tunneling magnetoresistance ratio of 64% using MgO (100) barrier layer prepared at room temperature

International Nuclear Information System (INIS)

Ohmori, Hideto; Hatori, Tomoya; Nakagawa, Shigeki

2008-01-01

MgO (100) textured films can be prepared by reactive facing targets sputtering at room temperature without postdeposition annealing process when they were deposited on (100) oriented Fe buffer layers. This method allows fabrication of perpendicular magnetic tunnel junction (p-MTJ) with MgO (100) tunneling barrier layer and rare-earth transition metal (RE-TM) alloy thin films as perpendicularly magnetized free and pinned layers. The 3-nm-thick MgO tunneling barrier layer in p-MTJ multilayer prepared on glass substrate revealed (100) crystalline orientation. Extraordinary Hall effect measurement clarified that the perpendicular magnetic components of 3-nm-thick Fe buffer layers on the two ends of MgO tunneling barrier layer were increased by exchange coupling with RE-TM alloy layers. The RA of 35 kΩ μm 2 and tunneling magnetoresistance ratio of 64% was observed in the multilayered p-MTJ element by current-in-plane-tunneling

Resonant tunnel magnetoresistance in a double magnetic tunnel junction

KAUST Repository

Useinov, Arthur

2011-08-09

We present quasi-classical approach to calculate a spin-dependent current and tunnel magnetoresistance (TMR) in double magnetic tunnel junctions (DMTJ) FML/I/FMW/I/FMR, where the magnetization of the middle ferromagnetic metal layer FMW can be aligned parallel or antiparallel with respect to the fixed magnetizations of the left FML and right FMR ferromagnetic electrodes. The transmission coefficients for components of the spin-dependent current, and TMR are calculated as a function of the applied voltage. As a result, we found a high resonant TMR. Thus, DMTJ can serve as highly effective magnetic nanosensor for biological applications, or as magnetic memory cells by switching the magnetization of the inner ferromagnetic layer FMW.© Springer Science+Business Media, LLC 2011.

Modeling of inter-ribbon tunneling in graphene

OpenAIRE

Van de Put, Maarten L.; Vandenberghe, William G.; Sorée, Bart; Magnus, Wim; Fischetti, Massimo

2015-01-01

The tunneling current between two crossed graphene ribbons is described invoking the empirical pseudopotential approximation and the Bardeen transfer Hamiltonian method. Results indicate that the density of states is the most important factor determining the tunneling current between small (nm) ribbons. The quasi-one dimensional nature of graphene nanoribbons is shown to result in resonant tunneling.

Design of Intelligent Power Supply System for Expressway Tunnel

Science.gov (United States)

Wang, Li; Li, Yutong; Lin, Zimian

2018-01-01

Tunnel lighting program is one of the key points of tunnel infrastructure construction. As tunnels tend to handle remote locations, power supply line construction generally has been having the distance, investment, high cost characteristics. To solve this problem, we propose a green, environmentally friendly, energy-efficient lighting system. This program uses the piston-wind which cars within tunnel produce as the power and combines with solar energy, physical lighting to achieve it, which solves the problem of difficult and high cost of highway tunnel section, and provides new ideas for the future construction of tunnel power supply.

LEP tunnel monorail

CERN Multimedia

1985-01-01

A monorail from CERN's Large Electron Positron collider (LEP, for short). It ran around the 27km tunnel, transporting equipment and personnel. With its 27-kilometre circumference, LEP was the largest electron-positron accelerator ever built and ran from 1989 to 2000. During 11 years of research, LEP's experiments provided a detailed study of the electroweak interaction. Measurements performed at LEP also proved that there are three – and only three – generations of particles of matter. LEP was closed down on 2 November 2000 to make way for the construction of the Large Hadron Collider in the same tunnel.

Energy Efficiency of Tunnel Boring Machines.

OpenAIRE

Grishenko, Vitaly

2014-01-01

Herrenknecht AG is a German world-leading Tunnel Boring Machines manufacturer showing strong awareness and concern regarding environmental issues. The company supports research on the Energy Efficiency (EE) of their products, aimed at the development of intelligent design for a green Tunnel Boring Machine. The aim of this project is to produce a ’status quo’ report on EE of three types of Tunnel Boring Machines (Hardrock, EPB and Mixshield TBM). In the framework of this research 39 projects a...

Automatic control of cryogenic wind tunnels

Science.gov (United States)

Balakrishna, S.

1989-01-01

Inadequate Reynolds number similarity in testing of scaled models affects the quality of aerodynamic data from wind tunnels. This is due to scale effects of boundary-layer shock wave interaction which is likely to be severe at transonic speeds. The idea of operation of wind tunnels using test gas cooled to cryogenic temperatures has yielded a quantrum jump in the ability to realize full scale Reynolds number flow similarity in small transonic tunnels. In such tunnels, the basic flow control problem consists of obtaining and maintaining the desired test section flow parameters. Mach number, Reynolds number, and dynamic pressure are the three flow parameters that are usually required to be kept constant during the period of model aerodynamic data acquisition. The series of activity involved in modeling, control law development, mechanization of the control laws on a microcomputer, and the performance of a globally stable automatic control system for the 0.3-m Transonic Cryogenic Tunnel (TCT) are discussed. A lumped multi-variable nonlinear dynamic model of the cryogenic tunnel, generation of a set of linear control laws for small perturbation, and nonlinear control strategy for large set point changes including tunnel trajectory control are described. The details of mechanization of the control laws on a 16 bit microcomputer system, the software features, operator interface, the display and safety are discussed. The controller is shown to provide globally stable and reliable temperature control to + or - 0.2 K, pressure to + or - 0.07 psi and Mach number to + or - 0.002 of the set point value. This performance is obtained both during large set point commands as for a tunnel cooldown, and during aerodynamic data acquisition with intrusive activity like geometrical changes in the test section such as angle of attack changes, drag rake movements, wall adaptation and sidewall boundary-layer removal. Feasibility of the use of an automatic Reynolds number control mode with

The responsiveness of sensibility and strength tests in patients undergoing carpal tunnel decompression

Directory of Open Access Journals (Sweden)

Miller Leanne

2011-10-01

Full Text Available Abstract Background Several clinical measures of sensory and motor function are used alongside patient-rated questionnaires to assess outcomes of carpal tunnel decompression. However there is a lack of evidence regarding which clinical tests are most responsive to clinically important change over time. Methods In a prospective cohort study 63 patients undergoing carpal tunnel decompression were assessed using standardised clinician-derived and patient reported outcomes before surgery, at 4 and 8 months follow up. Clinical sensory assessments included: touch threshold with monofilaments (WEST, shape-texture identification (STI™ test, static two-point discrimination (Mackinnon-Dellon Disk-Criminator and the locognosia test. Motor assessments included: grip and tripod pinch strength using a digital grip analyser (MIE, manual muscle testing of abductor pollicis brevis and opponens pollicis using the Rotterdam Intrinsic Handheld Myometer (RIHM. The Boston Carpal Tunnel Questionnaire (BCTQ was used as a patient rated outcome measure. Results Relative responsiveness at 4 months was highest for the BCTQ symptom severity scale with moderate to large effects sizes (ES = -1.43 followed by the BCTQ function scale (ES = -0.71. The WEST and STI™ were the most responsive sensory tests at 4 months showing moderate effect sizes (WEST ES = 0.55, STI ES = 0.52. Grip and pinch strength had a relatively higher responsiveness compared to thenar muscle strength but effect sizes for all motor tests were very small (ES ≤0.10 or negative indicating a decline compared to baseline in some patients. Conclusions For clinical assessment of sensibility touch threshold assessed by monofilaments (WEST and tactile gnosis measured with the STI™ test are the most responsive tests and are recommended for future studies. The use of handheld myometry (RIHM for manual muscle testing, despite more specifically targeting thenar muscles, was less responsive than grip or tripod

Large magnetocurrents in double-barrier tunneling transistors

International Nuclear Information System (INIS)

Lee, J.H.; Jun, K.-I.; Shin, K.-H.; Park, S.Y.; Hong, J.K.; Rhie, K.; Lee, B.C.

2005-01-01

Magnetic tunneling transistors (MTT) with double tunneling barriers are fabricated. The structure of the transistor is AFM/FM/I/FM/I/FM/AFM, and ferromagnetic layers serve as the emitter, base and collector. This double-barrier tunneling transistor (DBTT) has an advantage of controlling the potential between the base and collector, compared to the Schottky-barrier-based base and collector of MTT. We found that the collector current density of DBTT is at least 10 3 times larger than that of conventional MTT, since tunneling through AlO x barrier provides much larger current density than that through Schottky barrier

Resonant tunneling of electrons in quantum wires

International Nuclear Information System (INIS)

Krive, I.V.; Shekhter, R.I.; Jonson, M.; Krive, I.V.

2010-01-01

We considered resonant electron tunneling in various nanostructures including single wall carbon nanotubes, molecular transistors and quantum wires formed in two-dimensional electron gas. The review starts with a textbook description of resonant tunneling of noninteracting electrons through a double-barrier structure. The effects of electron-electron interaction in sequential and resonant electron tunneling are studied by using Luttinger liquid model of electron transport in quantum wires. The experimental aspects of the problem (fabrication of quantum wires and transport measurements) are also considered. The influence of vibrational and electromechanical effects on resonant electron tunneling in molecular transistors is discussed.

Reformulation of controlled-release oxycodone and pharmacy dispensing patterns near the US-Canada border.

Science.gov (United States)

Gomes, Tara; Paterson, J Michael; Juurlink, David N; Dhalla, Irfan A; Mamdani, Muhammad M

2012-01-01

In August 2010, a tamper-resistant formulation of controlled-release oxycodone (OxyContin-OP) was introduced in the United States but not in Canada. Our objective was to determine whether introduction of OxyContin-OP in the United States influenced prescription volumes for the original controlled-release oxycodone formulation (OxyContin) at Canadian pharmacies near the international border. We conducted a population-based, serial, cross-sectional study of prescriptions dispensed from pharmacies in the 3 cities with the highest volume of US-Canada border crossings in Ontario: Niagara Falls, Windsor and Sarnia. We analyzed data on all outpatient prescriptions for OxyContin dispensed by Canadian pharmacies near each border crossing between 2010 Apr. 1 and 2012 Feb. 29. We calculated and compared monthly prescription rates, adjusted per 1000 population and stratified by tablet strength. The number of tablets dispensed near 4 border crossings in the 3 Canadian cities remained stable over the study period. However, the rate of dispensing at pharmacies near the Detroit-Windsor Tunnel increased roughly 4-fold between August 2010 and February 2011, from 505 to 1969 tablets per 1000 population. By April 2011, following warnings to prescribers and pharmacies regarding drug-seeking behaviour, the dispensing rate declined to 1683 tablets per 1000 population in this area. By November 2011, the rate had returned to levels observed in early 2010. Our analyses suggest that 242 075 excess OxyContin tablets were dispensed near the Detroit-Windsor Tunnel between August 2010 and October 2011. Prescribing of the original formulation of controlled-release oxycodone rose substantially near a major international border crossing following the introduction of a tamper-resistant formulation in the United States. It is possible that the restriction of this finding to the area surrounding the Detroit-Windsor Tunnel reflects specific characteristics of this border crossing, including its high

Quantum tunneling of Bose-Einstein condensates in optical lattices

CERN Document Server

Fan Wen Bin

2003-01-01

In quantum tunneling a particle with energy E can pass through a high potential barrier V(>E) due to the wave character of the particle. Bose-Einstein condensates can display very strong tunneling depending on the structure of the trap, which may be a double-well or optical lattices. The employed for the first time to our knowledge the periodic instanton method to investigate tunneling of Bose-Einstein condensates in optical lattices. The results show that there are two kinds of tunneling in this system, Landau-Zener tunneling between extended states of the system and Wannier-Stark tunneling between localized states of the system, and that the latter is 1000 times faster than the former. The also obtain the total decay rate for a wide range of temperature, including classical thermal activation, thermally assisted tunneling and quantum tunneling. The results agree with experimental data in references. Finally, the propose an experimental protocol to observe this new phenomenon in future experiments

Resonant tunneling through double-barrier structures on graphene

International Nuclear Information System (INIS)

Deng Wei-Yin; Zhu Rui; Deng Wen-Ji; Xiao Yun-Chang

2014-01-01

Quantum resonant tunneling behaviors of double-barrier structures on graphene are investigated under the tight-binding approximation. The Klein tunneling and resonant tunneling are demonstrated for the quasiparticles with energy close to the Dirac points. The Klein tunneling vanishes by increasing the height of the potential barriers to more than 300 meV. The Dirac transport properties continuously change to the Schrödinger ones. It is found that the peaks of resonant tunneling approximate to the eigen-levels of graphene nanoribbons under appropriate boundary conditions. A comparison between the zigzag- and armchair-edge barriers is given. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Bilateral posterior tarsal tunnel syndrome caused by accessory flexor digitorum longus; case report and surgical technique.

Science.gov (United States)

Schmidt-Hebbel, A; Elgueta, J; Villa, A; Mery, P; Filippi, J

To present a case report of bilateral posterior tarsal tunnel syndrome (PTTS) caused by an accessory flexor digitorum longus (AFDL), including the surgical technique and a review of the literature. Twenty-nine year old male diagnosed with bilateral PTTS, refractory to conservative management, with 53 points on the preoperative AOFAS score. MR of both ankles showed an AFDL within the tarsal tunnel, in close relationship to the posterior tibial nerve. Bilateral tarsal tunnel decompression and AFDL resection was performed. There were no post-operative complications. At 6 months after surgery, the patient had no pain and had 87 points on the AOFAS score. The PTTS is an entrapment neuropathy of the posterior tibial nerve or one of its terminal branches. A rare cause is the presence of an AFDL, and its resection is associated with good clinical results. Careful scar tissue resection and neurolysis is recommended. Knowing the normal pathway and anatomical variability of the posterior tibial nerve and its branches is essential to avoid iatrogenic injury. In our case report, MR and intraoperative findings identified a bilateral FDLA in close relationship to the common flexor digitorum, an unusual finding, with few reports in current literature. Careful tarsal tunnel decompression and AFDL resection in our patient with bilateral symptomatic PTTS has good clinical results and no complications, particularly when diagnosed and treated early. Copyright © 2015 SECOT. Publicado por Elsevier España, S.L.U. All rights reserved.

Tunnel magnetoresistance in thermally robust Mo/CoFeB/MgO tunnel junction with perpendicular magnetic anisotropy

Directory of Open Access Journals (Sweden)

B. Fang

2015-06-01

Full Text Available We report on tunnel magnetoresistance and electric-field effect in the Mo buffered and capped CoFeB/MgO magnetic tunnel junctions (MTJs with perpendicular magnetic anisotropy. A large tunnel magnetoresistance of 120% is achieved. Furthermore, this structure shows greatly improved thermal stability and stronger electric-field-induced modulation effect in comparison with the Ta/CoFeB/MgO-based MTJs. These results suggest that the Mo-based MTJs are more desirable for next generation spintronic devices.

Insertion of a straight peritoneal catheter in an arcuate subcutaneous tunnel by a tunneler: long-term experience.

Science.gov (United States)

Favazza, A; Petri, R; Montanaro, D; Boscutti, G; Bresadola, F; Mioni, G

1995-01-01

This study describes the results of the insertion of a straight Tenckhoff peritoneal catheter (PC) in an arcuate, caudally concave tunnel using a tunneler designed by the authors. It has a semicircular shape and a bending radius of 4.5 cm. A hospital renal unit. From June 1988 to February 1994, 112 straight Tenckhoff PCs, 62 with one deep cuff (single-cuff PC) and 50 with two cuffs (double-cuff PC), were inserted as first catheters in 112 patients (mean age 62 +/- 13 years), who underwent continuous ambulatory peritoneal dialysis (CAPD). The follow-up was 1099 months (mean 18 +/- 13 months) for single-cuff PCs and 1264 months (mean 25 +/- 15 months) for double-cuff PCs, respectively. After intraperitoneal placement of the PCs by median laparotomy, a 180 degrees arc bend tunnel, with both external and peritoneal exits directed downwards, was created by means of the tunneler. The rate of exit-site infection (ESI) was 0.27 episodes/year (epis/year). The probability of remaining ESI-free was 76%, 60%, and 55% at 1, 2, and 3 years. The rate of tunnel infection (TI) was 0.046 epis/year. The incidence of the double-cuff PC-related ESI and TI tended to be lower than the incidence observed with the single-cuff PC. Episodes of peritonitis were 60 (0.30 epis/year), where 6 were subsequent to ESI and/or TI. Two PCs were lost due to ESI, 3 due to TI, and 11 due to peritonitis. Drainage failure, due to displacement of the PC caused by straightening, involved 3 PCs; 2 were lost. PC survival was 92%, 82%, and 74% at 1, 2 and 3 years, respectively. By an easily used semicircular tunneler, the standard straight Tenckhoff PC can be stably positioned in an arcuate tunnel with both inner and outer exits directed downwards. This tunnel shape, as already suggested by some authors, appears to be an effective technical solution to reducing the PC-related complication rates.

Theory of tunneling and photoemission spectroscopy for high-temperature superconductors

International Nuclear Information System (INIS)

Kouznetsov, K.; Coffey, L.

1996-01-01

A comprehensive analysis is presented of the tunneling conductance and angle-resolved photoemission spectra in high-temperature superconductors. It is shown that unexplained features of the tunneling and photoemission spectra such as broad backgrounds, dips, and asymmetry of the tunneling conductance can arise in a model of spin-fluctuation mediated inelastic tunneling. Effects of directionality in tunneling play an important role in determining the behavior of the tunneling conductance. copyright 1996 The American Physical Society

CURRENT ASSET TUNNELING AND FIRM PERFORMANCE IN AN EMERGING MARKET

OpenAIRE

Ratna Candra Sari; Zaki Baridwan

2014-01-01

This study examines the effect of current asset tunneling on firm performance from the emerging market perspective. Although tunneling activities is a common practices by businesses especially in Indonesia, there exist obstacles in the measurement of tunneling activity because it is difficult to proof the existence of such practices. In this study, we measure tunneling by using accounts receivables and develop tunneling detection criteria. In addition, this study examines the effect of tunnel...

Current status of submucosal tunneling endoscopic resection for gastrointestinal submucosal tumors originating from the muscularis propria layer.

Science.gov (United States)

Tan, Yuyong; Huo, Jirong; Liu, Deliang

2017-11-01

Gastrointestinal submucosal tumors (SMTs) have been increasingly identified via the use of endoscopic ultrasonography, and removal is often recommended for SMTs that are >2 cm in diameter or symptomatic. Submucosal tunneling endoscopic resection (STER), also known as submucosal endoscopic tumor resection, endoscopic submucosal tunnel dissection or tunneling endoscopic muscularis dissection, is a novel endoscopic technique for treating gastrointestinal SMTs originating from the muscularis propria layer, and has been demonstrated to be effective in the removal of SMTs with a decreased rate of recurrence by clinical studies. STER may be performed for patients with esophageal or cardia SMTs, and its application has expanded beyond these types of SMTs due to modifications to the technique. The present study reviewed the applications, procedure, efficacy and complications associated with STER.

Spin tunnelling in mesoscopic systems

Indian Academy of Sciences (India)

We study spin tunnelling in molecular magnets as an instance of a mesoscopic phenomenon, with special emphasis on the molecule Fe8. We show that the tunnel splitting between various pairs of Zeeman levels in this molecule oscillates as a function of applied magnetic field, vanishing completely at special points in the ...

Ferroelectric tunneling element and memory applications which utilize the tunneling element

Science.gov (United States)

Kalinin, Sergei V [Knoxville, TN; Christen, Hans M [Knoxville, TN; Baddorf, Arthur P [Knoxville, TN; Meunier, Vincent [Knoxville, TN; Lee, Ho Nyung [Oak Ridge, TN

2010-07-20

A tunneling element includes a thin film layer of ferroelectric material and a pair of dissimilar electrically-conductive layers disposed on opposite sides of the ferroelectric layer. Because of the dissimilarity in composition or construction between the electrically-conductive layers, the electron transport behavior of the electrically-conductive layers is polarization dependent when the tunneling element is below the Curie temperature of the layer of ferroelectric material. The element can be used as a basis of compact 1R type non-volatile random access memory (RAM). The advantages include extremely simple architecture, ultimate scalability and fast access times generic for all ferroelectric memories.

Extended-release naltrexone for pre-release prisoners: A randomized trial of medical mobile treatment.

Science.gov (United States)

Gordon, Michael S; Vocci, Frank J; Fitzgerald, Terrence T; O'Grady, Kevin E; O'Brien, Charles P

2017-02-01

Extended-release naltrexone (XR-NTX), is an effective treatment for opioid use disorder but is rarely initiated in US prisons or with criminal justice populations. Mobile treatment for chronic diseases has been implemented in a variety of settings. Mobile treatment may provide an opportunity to expand outreach to parolees to surmount barriers to traditional clinic treatment. Male and female prisoners (240) with pre-incarceration histories of opioid use disorder who are within one month of release from prison will be enrolled in this randomized clinical trial. Participants are randomized to one of two study arms: 1) [XR-NTX-OTx] One injection of long-acting naltrexone in prison, followed by 6 monthly injections post-release at a community opioid treatment program; or 2) [XR-NTX+ MMTx] One injection of long-acting naltrexone in prison followed by 6 monthly injections post-release at the patient's place of residence utilizing mobile medical treatment. The primary outcomes are: treatment adherence; opioid use; criminal activity; re-arrest; reincarceration; and HIV risk-behaviors. We describe the background and rationale for the study, its aims, hypotheses, and study design. The use of long-acting injectable naltrexone may be a promising form of treatment for pre-release prisoners. Finally, as many individuals in the criminal justice system drop out of treatment, this study will assess whether treatment at their place of residence will improve adherence and positively affect treatment outcomes. ClinicalTrials.gov: NCT02867124. Copyright © 2016 Elsevier Inc. All rights reserved.

Hybrid inflation exit through tunneling

International Nuclear Information System (INIS)

Garbrecht, Bjoern; Konstandin, Thomas

2007-01-01

For hybrid inflationary potentials, we derive the tunneling rate from field configurations along the flat direction towards the waterfall regime. This process competes with the classically rolling evolution of the scalar fields and needs to be strongly subdominant for phenomenologically viable models. Tunneling may exclude models with a mass scale below 10 12 GeV, but can be suppressed by small values of the coupling constants. We find that tunneling is negligible for those models, which do not require fine tuning in order to cancel radiative corrections, in particular for GUT-scale SUSY inflation. In contrast, electroweak scale hybrid inflation is not viable, unless the inflaton-waterfall field coupling is smaller than approximately 10 -11

Spin dynamics in tunneling decay of a metastable state

OpenAIRE

Ban, Yue; Sherman, E. Ya.

2012-01-01

We analyze spin dynamics in the tunneling decay of a metastable localized state in the presence of spin-orbit coupling. We find that the spin polarization at short time scales is affected by the initial state while at long time scales both the probability- and the spin density exhibit diffraction-in-time phenomenon. We find that in addition to the tunneling time the tunneling in general can be characterized by a new parameter, the tunneling length. Although the tunneling length is independent...

Seismic prediction ahead of tunnel construction using Rayleigh-waves

OpenAIRE

Jetschny, Stefan; De Nil, Denise; Bohlen, Thomas

2008-01-01

To increase safety and efficiency of tunnel constructions, online seismic exploration ahead of a tunnel can become a valuable tool. We developed a new forward looking seismic imaging technique e.g. to determine weak and water bearing zones ahead of the constructions. Our approach is based on the excitation and registration of tunnel surface-waves. These waves are excited at the tunnel face behind the cutter head of a tunnel boring machine and travel into drilling direction. Arriving at the fr...

Interaction Driven Interband Tunneling of Bosons in the Triple Well

OpenAIRE

Cao, Lushuai; Brouzos, Ioannis; Zöllner, Sascha; Schmelcher, Peter

2010-01-01

We study the tunneling of a small ensemble of strongly repulsive bosons in a one-dimensional triple-well potential. The usual treatment within the single-band approximation suggests suppression of tunneling in the strong interaction regime. However, we show that several windows of enhanced tunneling are opened in this regime. This enhanced tunneling results from higher band contributions, and has the character of interband tunneling. It can give rise to various tunneling processes, such as si...

Quantum tunneling of magnetization in solids

International Nuclear Information System (INIS)

Stamp, P.C.E.; Barbara, B.

1992-01-01

Magnetic solids should, under certain circumstances, show macroscopic quantum behavior, in which coherence exists between completely distinct magnetization states, each involving a very large number of spins (∼10 12 spins). This article reviews the recent work in this field, concentrating particularly on macroscopic quantum tunneling (MQT) of magnetization. The two main phenomena discussed are the tunneling of magnetization in single-domain particles or grains (in which some 10 3 - 10 4 spins rotate together through an energy barrier), and the tunneling of domain walls in films or in bulk magnets; where walls containing ∼10 10 spins may tunnel off a pinning potential, or from one pinning center to another. Some attention is also given to the quantum nucleation of magnetization reversal in a bulk magnet, and to the quantum motion of other magnetic solitons (such as vortices). After a thorough analysis of the basic grain and wall tunneling phenomena, the authors continue on to a discussion of the various dissipative or decoherence mechanisms, which destroy the phase correlations involved in tunneling. The coupling of grain magnetization to phonons, photons, and electrons is shown to have little consequence for weakly-conducting or insulating grains. Domain walls couple to these and also to magnons and impurities or defects; the 3rd order coupling to magnons can have serious effects, but if one uses pure insulators at low temperatures, these can also be ignored

Proton tunnelling in intermolecular hydrogen bonds

Energy Technology Data Exchange (ETDEWEB)

Horsewill, A J [Nottingham Univ. (United Kingdom); Johnson, M R [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France); Trommsdorff, H P [Grenoble-1 Univ., 38 (France)

1997-04-01

The wavefunctions of particles extend beyond the classically accessible regions of potential energy-surfaces (PES). A manifestation of this partial delocalization is the quantum-mechanical tunneling effect which enables a particle to escape from a metastable potential-well. Tunnelling is most important for the lightest atoms, so that the determination of its contribution to proton transfer, one of the most fundamental chemical reactions, is an important issue. QENS and NMR techniques have been employed to study the motion of protons in the hydrogen bond of benzoic-acid crystals, a system which has emerged as a particularly suitable model since proton transfer occurs in a near symmetric double-well potential. The influence of quantum tunnelling was revealed and investigated in these experiments. This work provides an experimental benchmark for theoretical descriptions of translational proton-tunnelling. (author). 7 refs.

Climatic wind tunnel for wind engineering tasks

Czech Academy of Sciences Publication Activity Database

Kuznetsov, Sergeii; Pospíšil, Stanislav; Král, Radomil

2015-01-01

Roč. 112, 2-B (2015), s. 303-316 ISSN 1897-628X R&D Projects: GA ČR(CZ) GA14-12892S Keywords : climatic tunnel * wind tunnel * atmospheric boundary layer * flow resistance * wind tunnel contraction Subject RIV: JM - Building Engineering https://suw.biblos.pk.edu.pl/resources/i5/i6/i6/i7/i6/r56676/KuznetsovS_ClimaticWind.pdf

Experience in design and construction of the Log tunnel

Directory of Open Access Journals (Sweden)

Jovičić Vojkan

2017-09-01

Full Text Available A twin highway Log tunnel is a part of a new motorway connection between Maribor and Zagreb, section Draženci-Gruškovje, which is located towards the border crossing between Slovenia and Croatia. The tunnel is currently under construction, and only the excavation works have been completed during the writing of this paper. The terrain in the area of the Log tunnel is diverse, and the route of the highway in its vicinity is characterised by deep excavations, bridges or viaducts. The Log tunnel is approximately 250 m long, partly constructed as a gallery. The geological conditions are dominated by Miocene base rock, featuring layers of well-connected clastic rocks, which are covered by diluvium clays, silts, sands and gravels of different thicknesses. Due to the short length of the tunnel, the usual separation of the motorway route to the left and the right tunnel axes was not carried out. Thus, the tunnel was constructed with an intermediate pillar and was designed as a three-lane tunnel, including the stopping lane. The construction of the tunnel was carried out using the New Austrian tunnelling method (NATM, in which the central adit was excavated first and the intermediate pillar was constructed within it. The excavation of the main tubes followed and was divided into the top heading, bench and the invert, enabling the intermediate pillar to take the load off the top heading of both tubes. The secondary lining of the tunnel is currently under construction. The experience of the tunnel construction gathered so far is presented in the paper. The main emphasis is on the construction of the intermediate pillar, which had to take the significant and asymmetrical ground load.

Experience in design and construction of the Log tunnel

Science.gov (United States)

Jovičić, Vojkan; Goleš, Niko; Tori, Matija; Peternel, Miha; Vajović, Stanojle; Muhić, Elvir

2017-09-01

A twin highway Log tunnel is a part of a new motorway connection between Maribor and Zagreb, section Draženci-Gru\\vskovje, which is located towards the border crossing between Slovenia and Croatia. The tunnel is currently under construction, and only the excavation works have been completed during the writing of this paper. The terrain in the area of the Log tunnel is diverse, and the route of the highway in its vicinity is characterised by deep excavations, bridges or viaducts. The Log tunnel is approximately 250 m long, partly constructed as a gallery. The geological conditions are dominated by Miocene base rock, featuring layers of well-connected clastic rocks, which are covered by diluvium clays, silts, sands and gravels of different thicknesses. Due to the short length of the tunnel, the usual separation of the motorway route to the left and the right tunnel axes was not carried out. Thus, the tunnel was constructed with an intermediate pillar and was designed as a three-lane tunnel, including the stopping lane. The construction of the tunnel was carried out using the New Austrian tunnelling method (NATM), in which the central adit was excavated first and the intermediate pillar was constructed within it. The excavation of the main tubes followed and was divided into the top heading, bench and the invert, enabling the intermediate pillar to take the load off the top heading of both tubes. The secondary lining of the tunnel is currently under construction. The experience of the tunnel construction gathered so far is presented in the paper. The main emphasis is on the construction of the intermediate pillar, which had to take the significant and asymmetrical ground load.

Understanding quantum tunneling using diffusion Monte Carlo simulations

Science.gov (United States)

Inack, E. M.; Giudici, G.; Parolini, T.; Santoro, G.; Pilati, S.

2018-03-01

In simple ferromagnetic quantum Ising models characterized by an effective double-well energy landscape the characteristic tunneling time of path-integral Monte Carlo (PIMC) simulations has been shown to scale as the incoherent quantum-tunneling time, i.e., as 1 /Δ2 , where Δ is the tunneling gap. Since incoherent quantum tunneling is employed by quantum annealers (QAs) to solve optimization problems, this result suggests that there is no quantum advantage in using QAs with respect to quantum Monte Carlo (QMC) simulations. A counterexample is the recently introduced shamrock model (Andriyash and Amin, arXiv:1703.09277), where topological obstructions cause an exponential slowdown of the PIMC tunneling dynamics with respect to incoherent quantum tunneling, leaving open the possibility for potential quantum speedup, even for stoquastic models. In this work we investigate the tunneling time of projective QMC simulations based on the diffusion Monte Carlo (DMC) algorithm without guiding functions, showing that it scales as 1 /Δ , i.e., even more favorably than the incoherent quantum-tunneling time, both in a simple ferromagnetic system and in the more challenging shamrock model. However, a careful comparison between the DMC ground-state energies and the exact solution available for the transverse-field Ising chain indicates an exponential scaling of the computational cost required to keep a fixed relative error as the system size increases.

Submucosal tunneling using endoscopic submucosal dissection for peritoneal access and closure in natural orifice transluminal endoscopic surgery: a porcine survival study.

Science.gov (United States)

Yoshizumi, F; Yasuda, K; Kawaguchi, K; Suzuki, K; Shiraishi, N; Kitano, S

2009-08-01

Safe peritoneal access and gastric closure are the most important concerns in the clinical application of natural orifice transluminal endoscopic surgery (NOTES). We aimed to clarify the feasibility of a submucosal tunnel technique using endoscopic submucosal dissection (ESD) for transgastric peritoneal access and subsequent closure for NOTES. Seven female pigs, each weighing about 40 kg were included in the study. The following procedures were performed: (i) after injection of normal saline into the submucosa, the mucosa was cut with a flex knife; (ii) the submucosal layer was dissected using an insulation-tipped electrosurgical knife to make a narrow longitudinal 50-mm submucosal tunnel; (iii) a small incision was made at the end of the tunnel and enlarged with a dilation balloon. After transgastric peritoneoscopy, the mucosal incision site was closed with clips. The following outcome measures were used: (a) evaluation of the technical feasibility of making a submucosal tunnel; (b) clinical monitoring for 7 days; (c) follow-up endoscopy and necropsy; and (d) peritoneal fluid culture. Natural orifice transluminal endoscopic peritoneoscopy with a submucosal tunnel was successfully carried out in all pigs. The pigs recovered well, without signs of peritonitis. Follow-up endoscopy showed healing of mucosal incision sites without open defects. Necropsy revealed no findings of peritonitis, confirming completeness of gastric closure; there was a thin scar in one pig and adhesion of the omentum in six pigs. Peritoneal fluid culture demonstrated no bacterial growth. The submucosal tunnel technique is feasible and effective for transgastric peritoneal access and closure.

New Method of Sinking Caisson Tunnel in Soft Soil

OpenAIRE

Bame, Abda Berisso

2013-01-01

Sinking a caisson tunnel in soft soil is new idea and this new concept could be an alternative method of tunneling in soft soil. The aim of this study is to evaluate geotechnical feasibility of sinking the caisson tunnel to the desired depth at the selected soil profile along tunnel alignment. This caisson tunneling method is proposed to reduce the use of temporary works such as propping of sheet pile walls and increase the ease and speed of construction. Besides, it reduces the disturbance o...

[Remote results of high myopia surgical correction by tunnel keratoplasty ].

Science.gov (United States)

Dushin, N V; Beliaev, V S; Gonchar, P A; Barashkov, V I; Kravchinina, V V; Frolov, M A

2000-01-01

Remote results evidence high refraction efficiency of tunnel keratoplasty, stable results being observed for up to 15 years. A total of 104 operations (58 patients) were analyzed for a period of observation of more than 10 years. The patients' ages varied from 17 to 52 years, there were 34 women and 24 men. The main advantage of interlamellar refraction meridional keratoplasty is easiness of operation. At present it is the operation of choice for dosed reduction of eye refraction aimed at correction of high myopia and astigmatism. The possibility of correcting residual myopia after keratotomy and repair of refraction abnormalities resultant from perforating keratoplasty is particularly interesting. The possibility of regulating the corrective effect in remote periods by replacing the implants also deserves attention. Hence, low traumatism, high efficiency, and stability of the refraction effect once more confirm our recommendation to use tunnel keratoplasty in clinical practice.

Energy Tunneling Behavior in Geometrically Separated Wave Guides

Directory of Open Access Journals (Sweden)

M. Omar

2017-10-01

Full Text Available In this paper, characteristics of energy tunneling channel between the waveguides geometrically separated by a coaxial cable are studied.  The novel aspect of design is use of coaxial channel to connect the waveguides while maintaining the energy tunneling phenomena. As anticipated the tunneling frequency depends upon the length of wire inside the waveguide and the length of the coaxial cable. The tunneling frequency also depends upon the dielectric constant of the material inside the waveguide and coaxial cable.  At tunneling frequency the field strength (E and H in the channel is extremely high, making the channel extremely sensitive to small change in permittivity of dielectric occupying the channel.  The advantage of the proposed design is, its ability to tune to desired tunneling frequency just by changing the length of the coaxial cable without the need to redesign the waveguide height to accommodate the long tunneling wires. This structure can be used as dielectric sensor both for solid or liquid dielectrics just by placing the sample in coaxial cable cavity, contrary to previously report work where the sample has to be placed inside the waveguide.

Predicting Tunnel Squeezing Using Multiclass Support Vector Machines

Directory of Open Access Journals (Sweden)

Yang Sun

2018-01-01

Full Text Available Tunnel squeezing is one of the major geological disasters that often occur during the construction of tunnels in weak rock masses subjected to high in situ stresses. It could cause shield jamming, budget overruns, and construction delays and could even lead to tunnel instability and casualties. Therefore, accurate prediction or identification of tunnel squeezing is extremely important in the design and construction of tunnels. This study presents a modified application of a multiclass support vector machine (SVM to predict tunnel squeezing based on four parameters, that is, diameter (D, buried depth (H, support stiffness (K, and rock tunneling quality index (Q. We compiled a database from the literature, including 117 case histories obtained from different countries such as India, Nepal, and Bhutan, to train the multiclass SVM model. The proposed model was validated using 8-fold cross validation, and the average error percentage was approximately 11.87%. Compared with existing approaches, the proposed multiclass SVM model yields a better performance in predictive accuracy. More importantly, one could estimate the severity of potential squeezing problems based on the predicted squeezing categories/classes.

CURRENT ASSET TUNNELING AND FIRM PERFORMANCE IN AN EMERGING MARKET

Directory of Open Access Journals (Sweden)

Ratna Candra Sari

2014-12-01

Full Text Available This study examines the effect of current asset tunneling on firm performance from the emerging market perspective. Although tunneling activities is a common practices by businesses especially in Indonesia, there exist obstacles in the measurement of tunneling activity because it is difficult to proof the existence of such practices. In this study, we measure tunneling by using accounts receivables and develop tunneling detection criteria. In addition, this study examines the effect of tunneling on firm performance and market reaction during the announcement of the related party transaction. The study finds that from the perspective of the being-tunneled companies, receivables to related parties negatively affect the company’s profit margin. Companies which announce related party transaction indicating tunneling obtain negative abnormal return during the announcement of the related party transaction.

Radiological effluents released from US continental tests, 1961 through 1992. Revision 1

International Nuclear Information System (INIS)

Schoengold, C.R.; DeMarre, M.E.; Kirkwood, E.M.

1996-08-01

This report documents all continental tests from September 15, 1961, through September 23, 1992, from which radioactive effluents were released. The report includes both updated information previously published in the publicly available May, 1990 report, DOE/NV-317, ''Radiological Effluents Released from Announced US Continental Tests 1961 through 1988'', and effluent release information on formerly unannounced tests. General information provided for each test includes the date, time, location, type of test, sponsoring laboratory and/or agency or other sponsor, depth of burial, purpose, yield or yield range, extent of release (onsite only or offsite), and category of release (detonation-time versus post-test operations). Where a test with simultaneous detonations is listed, location, depth of burial and yield information are given for each detonation if applicable, as well as the specific source of the release. A summary of each release incident by type of release is included. For a detonation-time release, the effluent curies are expressed at R+12 hours. For a controlled releases from tunnel-tests, the effluent curies are expressed at both time of release and at R+12 hours. All other types are listed at the time of the release. In addition, a qualitative statement of the isotopes in the effluent is included for detonation-time and controlled releases and a quantitative listing is included for all other types. Offsite release information includes the cloud direction, the maximum activity detected in the air offsite, the maximum gamma exposure rate detected offsite, the maximum iodine level detected offsite, and the maximum distance radiation was detected offsite. A release summary incudes whatever other pertinent information is available for each release incident. This document includes effluent release information for 433 tests, some of which have simultaneous detonations. However, only 52 of these are designated as having offsite releases

Radiological effluents released from US continental tests, 1961 through 1992. Revision 1

Energy Technology Data Exchange (ETDEWEB)

Schoengold, C.R.; DeMarre, M.E.; Kirkwood, E.M.

1996-08-01

This report documents all continental tests from September 15, 1961, through September 23, 1992, from which radioactive effluents were released. The report includes both updated information previously published in the publicly available May, 1990 report, DOE/NV-317, ``Radiological Effluents Released from Announced US Continental Tests 1961 through 1988``, and effluent release information on formerly unannounced tests. General information provided for each test includes the date, time, location, type of test, sponsoring laboratory and/or agency or other sponsor, depth of burial, purpose, yield or yield range, extent of release (onsite only or offsite), and category of release (detonation-time versus post-test operations). Where a test with simultaneous detonations is listed, location, depth of burial and yield information are given for each detonation if applicable, as well as the specific source of the release. A summary of each release incident by type of release is included. For a detonation-time release, the effluent curies are expressed at R+12 hours. For a controlled releases from tunnel-tests, the effluent curies are expressed at both time of release and at R+12 hours. All other types are listed at the time of the release. In addition, a qualitative statement of the isotopes in the effluent is included for detonation-time and controlled releases and a quantitative listing is included for all other types. Offsite release information includes the cloud direction, the maximum activity detected in the air offsite, the maximum gamma exposure rate detected offsite, the maximum iodine level detected offsite, and the maximum distance radiation was detected offsite. A release summary incudes whatever other pertinent information is available for each release incident. This document includes effluent release information for 433 tests, some of which have simultaneous detonations. However, only 52 of these are designated as having offsite releases.

High tunnels: protection for rather than from insect pests?

Science.gov (United States)

Ingwell, Laura L; Thompson, Sarah L; Kaplan, Ian; Foster, Ricky E

2017-12-01

High tunnels are a season extension tool creating a hybrid of field and greenhouse growing conditions. High tunnels have recently increased in the USA and thus research on their management is lacking. One purported advantage of these structures is protection from common field pests, but evidence to support this claim is lacking. We compared insect pest populations in high tunnels with field production over two years for three crops: tomato, broccoli and cucumber. Greenhouse pests (e.g. aphids, whiteflies) were more prevalent in high tunnels, compared to field plots. Hornworms (tobacco (Manduca sexta L.) and tomato (M. quinquemaculata Haworth)), a common field pest on tomato, were also more abundant in high tunnels, requiring chemical control while field populations were low. The crucifer caterpillar complex (imported cabbageworm (Pieris rapae L.), diamondback moth (Plutella xylostella L.) and cabbage looper (Trichoplusia ni Hübner)) was also more abundant in high tunnels in 2010. Cucumber beetle (striped (Acalymma vittatum F.) and spotted (Diabrotica undecimpunctata Mannerheim)) densities were higher in high tunnels in 2010 and field plots in 2011. The common assumption that high tunnels offer protection from field pests was not supported. Instead, high tunnel growing conditions may facilitate higher pest populations. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Effect of an Interfacial Layer on Electron Tunneling through Atomically Thin Al2O3 Tunnel Barriers.

Science.gov (United States)

Wilt, Jamie; Sakidja, Ridwan; Goul, Ryan; Wu, Judy Z

2017-10-25

Electron tunneling through high-quality, atomically thin dielectric films can provide a critical enabling technology for future microelectronics, bringing enhanced quantum coherent transport, fast speed, small size, and high energy efficiency. A fundamental challenge is in controlling the interface between the dielectric and device electrodes. An interfacial layer (IL) will contain defects and introduce defects in the dielectric film grown atop, preventing electron tunneling through the formation of shorts. In this work, we present the first systematic investigation of the IL in Al 2 O 3 dielectric films of 1-6 Å's in thickness on an Al electrode. We integrated several advanced approaches: molecular dynamics to simulate IL formation, in situ high vacuum sputtering atomic layer deposition (ALD) to synthesize Al 2 O 3 on Al films, and in situ ultrahigh vacuum scanning tunneling spectroscopy to probe the electron tunneling through the Al 2 O 3 . The IL had a profound effect on electron tunneling. We observed a reduced tunnel barrier height and soft-type dielectric breakdown which indicate that defects are present in both the IL and in the Al 2 O 3 . The IL forms primarily due to exposure of the Al to trace O 2 and/or H 2 O during the pre-ALD heating step of fabrication. As the IL was systematically reduced, by controlling the pre-ALD sample heating, we observed an increase of the ALD Al 2 O 3 barrier height from 0.9 to 1.5 eV along with a transition from soft to hard dielectric breakdown. This work represents a key step toward the realization of high-quality, atomically thin dielectrics with electron tunneling for the next generation of microelectronics.

Universal tunneling behavior in technologically relevant P/N junction diodes

International Nuclear Information System (INIS)

Solomon, Paul M.; Jopling, Jason; Frank, David J.; D'Emic, Chris; Dokumaci, O.; Ronsheim, P.; Haensch, W.E.

2004-01-01

Band-to-band tunneling was studied in ion-implanted P/N junction diodes with profiles representative of present and future silicon complementary metal-oxide-silicon (CMOS) field effect transistors. Measurements were done over a wide range of temperatures and implant parameters. Profile parameters were derived from analysis of capacitance versus voltage characteristics, and compared to secondary-ion mass spectroscopy analysis. When the tunneling current was plotted against the effective tunneling distance (tunneling distance corrected for band curvature) a quasi-universal exponential reduction of tunneling current versus, tunneling distance was found with an attenuation length of 0.38 nm, corresponding to a tunneling effective mass of 0.29 times the free electron mass (m 0 ), and an extrapolated tunneling current at zero tunnel distance of 5.3x10 7 A/cm 2 at 300 K. These results are directly applicable for predicting drain to substrate currents in CMOS transistors on bulk silicon, and body currents in CMOS transistors in silicon-on-insulator

Electrochemistry at a Metal Nanoparticle on a Tunneling Film: A Steady-State Model of Current Densities at a Tunneling Ultramicroelectrode.

Science.gov (United States)

Hill, Caleb M; Kim, Jiyeon; Bard, Allen J

2015-09-09

Here, a new methodology is proposed for treating electrochemical current densities in metal-insulator-metal nanoparticle (M-I-MNP) systems. The described model provides broad, practical insights about MNP-mediated electron transfer to redox species in solution, where electron transfer from the underlying electrode to a MNP via tunneling and heterogeneous electron transfer from the MNP to redox species in solution are treated as sequential steps. Tunneling is treated through an adaptation of the Simmons model of tunneling in metal-insulator-metal structures, and explicit equations are provided for tunneling currents, which demonstrate the effect of various experimental parameters, such as insulator thickness and MNP size. Overall, a general approach is demonstrated for determining experimental conditions where tunneling will have a measurable impact on the electrochemistry of M-I-MNP systems.

Tunneling and propping : a justification for pyramidal ownership

NARCIS (Netherlands)

Riyanto, Y.E.; Toolsema-Veldman, Linda

2004-01-01

This paper presents a formal model of tunneling and propping in a pyramidal ownership structure. Tunneling refers to controlling shareholders shifting resources from one firm to another in the same pyramid. Propping is tunneling that is done to save the receiving firm from bankruptcy. We compare the

A wind tunnel study on the effect of trees on PM2.5 distribution around buildings.

Science.gov (United States)

Ji, Wenjing; Zhao, Bin

2018-03-15

Vegetation, especially trees, is effective in reducing the concentration of particulate matter. Trees can efficiently capture particles, improve urban air quality, and may further decrease the introduction of outdoor particles to indoor air. The objective of this study is to investigate the effects of trees on particle distribution and removal around buildings using wind tunnel experiments. The wind tunnel is 18m long, 12m wide, and 3.5m high. Trees were modeled using real cypress branches to mimic trees planted around buildings. At the inlet of the wind tunnel, a "line source" of particles was released, simulating air laden with particulate matter. Experiments with the cypress tree and tree-free models were conducted to compare particle concentrations around the buildings. The results indicate that cypress trees clearly reduce PM 2.5 concentrations compared with the tree-free model. The cypress trees enhanced the PM 2.5 removal rate by about 20%. The effects of trees on PM 2.5 removal and distribution vary at different heights. At the base of the trees, their effect on reducing PM 2.5 concentrations is the most significant. At a great height above the treetops, the effect is almost negligible. Copyright © 2017 Elsevier B.V. All rights reserved.

General risks for tunnelling projects: An overview

Science.gov (United States)

Siang, Lee Yong; Ghazali, Farid E. Mohamed; Zainun, Noor Yasmin; Ali, Roslinda

2017-10-01

Tunnels are indispensable when installing new infrastructure as well as when enhancing the quality of existing urban living due to their unique characteristics and potential applications. Over the past few decades, there has been a significant increase in the building of tunnels, world-wide. Tunnelling projects are complex endeavors, and risk assessment for tunnelling projects is likewise a complex process. Risk events are often interrelated. Occurrence of a technical risk usually carries cost and schedule consequences. Schedule risks typically impact cost escalation and project overhead. One must carefully consider the likelihood of a risk's occurrence and its impact in the context of a specific set of project conditions and circumstances. A project's goals, organization, and environment impacts in the context of a specific set of project conditions and circumstances. Some projects are primarily schedule driven; other projects are primarily cost or quality driven. Whether a specific risk event is perceived fundamentally as a cost risk or a schedule risk is governed by the project-specific context. Many researchers have pointed out the significance of recognition and control of the complexity, and risks of tunnelling projects. Although all general information on a project such as estimated duration, estimated cost, and stakeholders can be obtained, it is still quite difficult to accurately understand, predict and control the overall situation and development trends of the project, leading to the risks of tunnelling projects. This paper reviews all the key risks for tunnelling projects from several case studies that have been carried out by other researchers. These risks have been identified and reviewed in this paper. As a result, the current risk management plan in tunnelling projects can be enhanced by including all these reviewed risks as key information.

Large positive spin polarization and giant inverse tunneling magnetoresistance in Fe/PbTiO3/Fe multiferroic tunnel junction

International Nuclear Information System (INIS)

Dai, Jian-Qing; Zhang, Hu; Song, Yu-Min

2014-01-01

We perform first-principles electronic structure and spin-dependent transport calculations of a multiferroic tunnel junction (MFTJ) with an epitaxial Fe/PbTiO 3 /Fe heterostructure. We predict a large positive spin-polarization (SP) and an intriguing giant inverse tunneling magnetoresistance (TMR) ratio in this tunnel junction. We demonstrate that the tunneling properties are determined by ferroelectric (FE) polarization screening and electronic reconstruction at the interface with lower electrostatic potential. The intricate complex band structure of PbTiO 3 , in particular the lowest decay rates concerning Pb 6p z and Ti 3d z2 states near the Γ ¯ point, gives rise to the large positive SP of the tunneling current in the parallel magnetic configuration. However, the giant inverse TMR ratio is attributed to the minority-spin electrons of the interfacial Ti 3d xz +3d yz orbitals which have considerably weight in the extended area around the Γ ¯ point at the Fermi energy and causes remarkable contributions to the conductance in the antiparallel magnetic configuration. - Highlights: • We study spin-dependent tunneling in Fe/PbTiO 3 /Fe multiferroic tunnel junction. • We find a large positive spin polarization in the parallel magnetic configuration. • An intriguing giant inverse TMR ratio (about −2000%) is predicted. • Complex band structure of PbTiO 3 causes the large positive spin polarization. • Negative TMR is due to minority-spin electrons of interfacial Ti d xz +d yz orbitals

Tunnel operator training with a conversational agent-assistant

NARCIS (Netherlands)

Buiel, E.; Lubbers, J.; Doesburg, W. van; Muller, T.

2009-01-01

A tunnel operator monitors and regulates the flow of traffic inside a tunnel. Tunnel operators need to train in a simulator regularly in order to maintain proficiency in handling incident situations. During quiet working hours, the operator has enough time for training. But generally at that time no

Spin polarization at the interface and tunnel magnetoresistance

International Nuclear Information System (INIS)

Itoh, H.; Inoue, J.

2001-01-01

We propose that interfacial states of imperfectly oxidized Al ions may exist in ferromagnetic tunnel junctions with Al-O barrier and govern both the spin polarization and tunnel conductance. It is shown that the spin polarization is positive independent of materials and correlates well with the tunnel magnetoresistance

Flow-Based Detection of DNS Tunnels

NARCIS (Netherlands)

Ellens, W.; Żuraniewski, P.; Sperotto, A.; Schotanus, H.; Mandjes, M.; Meeuwissen, E.

2013-01-01

DNS tunnels allow circumventing access and security policies in firewalled networks. Such a security breach can be misused for activities like free web browsing, but also for command & control traffic or cyber espionage, thus motivating the search for effective automated DNS tunnel detection

Flow-based detection of DNS tunnels

NARCIS (Netherlands)

Ellens, W.; Zuraniewski, P.; Schotanus, H.; Mandjes, M.R.H.; Meeuwissen, E.; Doyen, Guillaume; Waldburger, Martin; Celeda, Pavel; Sperotto, Anna; Stiller, Burkhard

DNS tunnels allow circumventing access and security policies in firewalled networks. Such a security breach can be misused for activities like free web browsing, but also for command & control traffic or cyber espionage, thus motivating the search for effective automated DNS tunnel detection