Science.gov (United States)

In a 47-year-old male patient a bronchopleural fistula was apparent 22 days after extended right-sided diaphragma-pericardio-pleuro-pneumonectomy for pleuramesothelioma. The thoracic cavity was infected. Rethoracotomy was performed and the fistula was closed using an omental pedicle flap. The bronchial stump became tight and the cavity fluid became sterile. No abdominal complications were seen. The patient died 8 months later from malignant pericardial infiltration. The ability of greater omentum to revascularize ischemic tissue, to absorb fluid and to resist local infection is proved and used in several subspecialities of surgery. Nevertheless the use of the greater omentum in the management of bronchopleural fistula has been rarely published. The reported case shows that the closure of a large bronchopleural fistula is possible by using the attributes of the omental tissue. PMID:2264043

Energy Technology Data Exchange (ETDEWEB)

The prevalence of hepatic cysts is 0.1% to 0.5% based on autopsy studies, and 2.5% based on US examinations. Percutaneous therapies are a new alternative to surgery. They include simple percutaneous aspiration, catheter drainage alone, and catheter drainage with sclerotherapy. We present an 11-year-old boy admitted to hospital because of abdominal pain. A diagnosis of simple hepatic cyst was made, which was treated with aspiration and tetracycline hydrochloride solution (5%) injection into the cystic cavity. Complete regression was seen on US and MRI examination at 3 months, with total collapse and deflation of the cyst. The cyst regressed totally, leaving a hyperechoic linear scar on US examination at 1 year. On the basis of the clinical and imaging results obtained, percutaneous sclerotherapy of hepatic cysts can be recommended as the treatment of choice and as a valid alternative to laparoscopy in children. (orig.)

UK PubMed Central (United Kingdom)

Splenic trauma in children following blunt abdominal injury is usually treated by nonoperative management (NOM). Splenectomy following abdominal trauma is rare in children. NOM is successful as in the...Full Text Available

Science.gov (United States)

PMID:18721983

CERN Document Server

RF Cavities and Power Amplifier for the Compact Proton Synchrotron

UK PubMed Central (United Kingdom)

We designed a multicenter study to compare tobramycin/clindamycin to imipenem/cilastatin for intra-abdominal infections. We included the Acute Physiology and Chronic Health Evaluation (APACHE II) index...Full Text Available

UK PubMed Central (United Kingdom)

This is a report of surgical treatment of thoracoabdominal aortic aneurysms and aneurysms of the abdominal aorta from which the visceral vessels arise during the 18 year period from April 5, 1960,...Full Text Available

UK PubMed Central (United Kingdom)

OBJECTIVE: The management and outcome of 138 abdominal shotgun wounds were examined over a 5-year period. SUMMARY BACKGROUND DATA: It has been proposed that exploratory laparotomy may be unnecessary...Full Text Available

International Nuclear Information System (INIS)

The diagnostic accuracy of computed tomography (CT) in several patterns of thoracic and abdominal fatty masses, has been examined. In selected cases our findings overlap the features of the recent literature. The possibility of surgical therapy in peculiar cases of adipose deposits, commonly esteemed benign, is considered.

Energy Technology Data Exchange (ETDEWEB)

Radiological findings of chest and abdominal wall involvement in Hodgkin's disease are reported. This manifestation was diagnosed in one patient in the primary staging and in two patients during the course of the disease. Typical radiological findings are soft tissue masses in the chest and abdominal wall, in two cases with continous tumor growth of enlarged mediastinal lymphnodes into the anterior chest wall. The axial computed tomography is the best method to evaluate the extent of chest and abdominal wall involvement in Hodgkin's disease.

Medline Plus

... energy. It consists of a stack of piezoelectric ceramics sandwiched under high pressure between two metal cylinders. ...

International Nuclear Information System (INIS)

The authors report the personal techniques and the results of CT-guided percutaneous drainage of postoperative abdominal fluid collections. CT-guided percutaneous drainage offers many advantages over surgery: it is less invasive, can be repeated and requires no anesthesia, there are not surgery-related risks and lower morbidity and mortality rates. Moreover, subsequent hospitalization is shorter and costs are consequently reduced. The authors conclude that CT-guided percutaneous drainage is the method of choice in the treatment of postoperative abdominal fluid collections.

Energy Technology Data Exchange (ETDEWEB)

In this paper the authors prove a uniqueness theorem for the electric detection of cavities in a three dimensional solid from Cauchy data measured on the surface. The cavities, finite in number, are assumed to be insulating. The surfaces of the cavities are assumed to be smooth on the complement of a set that is, in some sense, negligible. (orig.)

British Library Electronic Table of Contents (United Kingdom)

Purpose The laparoscopic surgical approach to unilateral intra-abdominal testis has replaced the open approach at several large centers. There is considerable literature on experience with unilateral intra-abdominal testes but little on the management of bilateral intra-abdominal testes. We assessed the feasibility and safety of performing single setting bilateral laparoscopic orchiopexy in boys with bilateral intra-abdominal testes. Materials and Methods A single surgeon experience was reviewed. The surgical technique was similar in all cases and on each side, including infra-umbilical access, diagnostic evaluation, peritoneal mobilization lateral to the spermatic vessels and inferior to the vas deferens, gubernacular transection, and a decision for or against a Fowler-Stephens procedure ...

International Nuclear Information System (INIS)

Nasal cavity volume was studied in 69 healthy volunteers (from 8 to 23 years old) by MRI. The right and left nasal cavity areas were measured on horizontal images displayed directly on the MRI console. The nasal cavity volume was obtained by integrated volume calculation. The nasal cavity volume was positively correlated with age, body height and weight up to age 16. The body height and weight reached a plateau at 16 years, but the nasal cavity volume continued to increase. There was no significant difference in the volumes of the right and left cavities. (author).

International Nuclear Information System (INIS)

(1974). United States Haddad, H. Bounous, G. Tahan, WT Devroede, G.

British Library Electronic Table of Contents (United Kingdom)

Effect of Abdominal Active Can on DFTs. Introduction: Many patients with implantable cardioverter defibrillators (ICDs) have older lead systems, which are usually not replaced at the time of pulse generator replacement unless a malfunction is noted. Therefore, optimization of defibrillation with these lead systems is clinically important. The objective of this prospective study was to determine if an active abdominal pulse generator (Can) affects chronic defibrillation thresholds (DFTs) with a dual-coil, transvenous ICD lead system. Methods and Results: The study population consisted of 39 patients who presented for routine abdominal pulse generator replacement. Each patient underwent two assessments of DFT using a step-down protocol, with the order of testing randomized. The distal right ...

International Nuclear Information System (INIS)

The cross-coupled interferometer is a new design for interferometric gravitational wave detectors. Similar to the baseline gravitational wave detectors proposed for Advanced LIGO, it uses long-arm cavities in which the signal is generated. The signal fields are then extracted from the arm cavities with an additional cavity behind the long-arm cavities. The tuning of this signal extraction cavity and the parallel tuning of the signal recycling mirror can be used to optimize the peak frequency and the bandwidth of the detector independently. If we replace the signal recycling mirror by a small cavity, it is possible to amplify signals in two different frequency bands.

Energy Technology Data Exchange (ETDEWEB)

In a joint study conducted by the University Clinic of Radiology, Graz, and the Medical University Clinic, Innsbruck, the results of computer tomography examinations of the abdomen and pelvis in 23 cases of tumours in children are discussed. In children computer tomography resents special difficulties on account of the very poorly developed fatty layers between the organs and the increased incidence of movement artifacts. The importance of computer tomography for the diagnosis of abdominal and pelvic tumours is discussed.

International Nuclear Information System (INIS)

Complex abdominal lesions include a variety of pathologies, such as septated, infected, and hemorrhagic cysts, abscesses, tumors, and fluid collections of different ethiology. These lesions present diagnostic difficulties with both Ultrasonography (US) and Computed Tomography (CT), since findings may not be present or, when present, are not specific. Keeping these limitations in mind, we evaluated 105 patients (111 abdominal lesions) with both US and CT in order to compare their adequacy in predicting the nature of the lesion. On the basis of US and CT results, complex abdominal lesions were divided in four classes: class I includes 43 cases in which both examinations gave the same contribution to the definition of the nature of the lesion, class II (14 lesions, mainly sperimentated cysts), in which US was superior to CT, class III includes 45 cases of hemorrhagic cysts, abscesses, fluid collections and, less frequently, ...

International Nuclear Information System (INIS)

Short communication.

Energy Technology Data Exchange (ETDEWEB)

Visible laser light output from an electrically injected vertical cavity surface emitting laser (VSCEL) diode is enabled by the addition of phase-matching spacer layers on either side of the active region to form the optical cavity. The spacer layers comprise InAlP which act as charge carrier confinement means. Distributed Bragg reflector layers are formed on either side of the optical cavity to act as mirrors. 5 figs.

Energy Technology Data Exchange (ETDEWEB)

A model for energy transport in a solid particle cavity receiver is developed and applied to the design and analysis of a receiver for the Central Receiver Test Facility (CRTF), Albuquerque, New Mexico. The model gives thermal performance results - including particle temperatures, cavity efficiencies, and wall temperatures - which directly affect the economic and technical feasibility of a solid particle receiver. In addition, design criteria relevant to the configuration of a solid particle cavity receiver are developed. Results for CRTF indicate that at design conditions particle temperatures will exceed 1200/sup 0/K with cavity efficiencies on the order of 75%.

CERN Document Server

Individual laser cooled atoms are delivered on demand from a single atom magneto-optic trap to a high-finesse optical cavity using an atom conveyor. Strong coupling of the atom with the cavity field allows simultaneous cooling and detection of individual atoms for time scales exceeding 15 s. The single atom scatter rate is studied as a function of probe-cavity detuning and probe Rabi frequency, and the experimental results are in good agreement with theoretical predictions. We demonstrate the ability to manipulate the position of a single atom relative to the cavity mode with excellent control and reproducibility.

International Nuclear Information System (INIS)

Cavity ringdown spectroscopy (CRDS) with continuous-wave (cw) laser excitation has added high frequency resolution to the ability of CRDS being used for the absolute quantification of trace-level species present in many chemical processes. Cavity dithering technique has easily resolved the problem of resonant coupling of a cw laser light into a high-finesse cavity. The present study addresses the potential uncertainty involved in such cw-CRDS techniques incorporating the cavity mirror motion, i.e., the doppler frequency shift of a probe light inside the cavity. In the high-resolution spectroscopic work of megahertz-accuracy, even the influence of intracavity doppler effect may become significant.

CERN Document Server

The concept of the 'white-light cavity' has recently generated considerable research interest in the context of gravitational wave detection. Cavity designs are proposed using negative (or anomalous) dispersion in an intracavity medium to make the cavity resonate over a large range of frequencies and still maintain a high cavity build-up. This paper presents the first experimental attempt and demonstration of white-light effect in a meter long ring cavity using an intracavity atomic medium. The medium's negative dispersion is caused by bi-frequency Raman gain in an atomic vapor cell. Although the white light condition was not perfectly achieved and improvements in experimental control are still desirable, significantly broad cavity response over bandwidth greater than 20 MHz has been observed. These devices will have potential applications in new generation ...

UK PubMed Central (United Kingdom)

Forty-two patients were treated with intravenous cefoxitin, a new cephamycin antibiotic. These patients had postoperative abdominal sepsis (26), intrathoracic infections (6), urinary tract infections...Full Text Available

Science.gov (United States)

Results are reported from studies of the diffusion rate of xenon through frog abdominal skin and toad urinary bladders, typical epithelial membranes. It was concluded that intracellular water serves as the principal barrier for xenon passage through epithelial tissue.

UK PubMed Central (United Kingdom)

BackgroundControversy exists about how to effectively measure patient reported outcomes in IBS clinical trials. Pain numeric rating scales (NRS) are widely used in...Full Text Available

UK PubMed Central (United Kingdom)

Biliary obstructions are rarely caused by a foreign body and have received sparse attention. We present an unusual case with pruritis and abdominal pain caused by impacted full length surgical gauze...Full Text Available

UK PubMed Central (United Kingdom)

Cystic neoplasms of the pancreas are increasingly recognized due to the expanding use and improved sensitivity of cross-sectional abdominal imaging. Major advances in the last decade have led to an...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

As a consequence of the expanded use of long term hemodialysis and continuous ambulatory peritoneal dialysis (CAPD) treatments and extended life spans, complications of end-stage renal disease and dialysis treatments are being encountered with increasing frequency in these patients. Computed tomography can accurately depict many of the potential complications of end-stage renal disease on dialysis. This article presents the abdominal CT findings of 429 end-stage renal disease patients who are on either hemodialysis or continuous ambulatory peritoneal dialysis treatment.

Energy Technology Data Exchange (ETDEWEB)

The dwelling is equipped with solar collectors which heat the air circulating in the cavity walls and the space beneath the floors. The thermal aspects of such a building are described. Heat balance, losses, heating by the sun in different seasons are described. Different measures taken to reduce the energy losses are described.

Energy Technology Data Exchange (ETDEWEB)

Apparatus for minimizing thermal loss in a windowless, open cavity solar receiver due to airflow at the receiver aperture includes means for deflecting wind away from the cavity opening such that flow stream reattachment occurs away from the receiver aperture to provide a dead air zone at the cavity opening. This prevents turbulent-mixing airflow exchange between ambient air and heated air within the solar receiver. The wind deflector apparatus includes either a passive annular deflection foil at the receiver aperture, or an active device for producing an outwardly projected air jet at the receiver aperture.

International Nuclear Information System (INIS)

We report on a promising approach to high-sensitivity anisotropy measurements using a high-finesse cavity locked by optical feedback to a diode laser. We provide a simple and effective way to decouple the weak anisotropy of interest from the inherent mirror's birefringence whose drift may be identified as the key limiting parameter in cavity-based techniques. We demonstrate a shot-noise-limited phase shift resolution previously inaccessible in an optical cavity, readily achieving the state-of-the-art level of 3x10"-"1"3 rad.

Science.gov (United States)

Convective losses arising from buoyancy driven flow were calculated for a two-dimensional model simulating a solar cavity receiver. The TEMPEST code, capable of fully three-dimensional coupled thermal-hydraulic transient calculations, was used for the simulation. Predicted velocity and temperature results for a 2.59 m deep by 2.88 m high rectangular cavity with an aperture opening of 1.72 m were used to determine convective losses for prescribed interior wall temperatures and cavity orientation. Velocity vector and temperature isotherm plots were used to analyze flow characteristics.

Energy Technology Data Exchange (ETDEWEB)

An analytical model is presented which enables the estimation of convective losses from cavity receivers. Evidence from solar experiments is used to test the hypothesized mechanisms. The analytical results and experimental evidence indicate that the convective loss from cavity receivers is appreciable. The model indicates that the influences of the wind on the convective loss at normal operating conditions are minimal. It also shows that the internal thermal resistance, i.e. the ability to heat the air inside the cavity, are of importance. Buoyancy induced flows are, on the other hand, effective in transferring energy across the aperture. 8 refs.

Energy Technology Data Exchange (ETDEWEB)

A new type of impregnation jelly can be used instead of traditional oil may reduce the formation of cavities in marine high-voltage direct current cables. This provides a foundation for the development of cables with improved insulation and for higher power. This was a conclusion of the Norwegian ''EFFEKT''-project. Using the jelly reduces the size of the cavities substantially and no discharges seem to occur during formation, growth and collapse of cavities. It is also environmentally friendly, since there is no leakage of oil.

International Nuclear Information System (INIS)

The high-power model of Disk-and Washer (DAW) cavity for electron acceleration is under fabrication. Basic Dimensions of the cavity were determined from aluminum model measurement and electromagnetic field calculation. We have fabricated model made of OFC (Oxygen Free Copper) five times in total. Some details are optimized and corrected, and then the final brazing are proceeding. These model results and present status are described. (author)

CERN Document Server

We propose a scheme able to generate stationary continuous variable entanglement between an optical and a microwave cavity mode by means of their common interaction with a micro-mechanical resonator. We show that when both cavities are intensely driven one can generate bipartite entanglement between any pair of the tripartite system, and that, due to entanglement sharing, optical-microwave entanglement is efficiently generated at the expense of microwave-mechanical and opto-mechanical entanglement.

International Nuclear Information System (INIS)

In this paper, finite-difference time-domain method is used to research the transient electromagnetic pulse (EMP) coupling to the cylinder object which is shielded in another shielding cavity with a hole numerically. The different coupling effectiveness of three transient EMP is simulated. The distribution of the electric field in the shielding cavity and the current on the cavity are researched. The shielding effectiveness is evaluated. (authors)

International Nuclear Information System (INIS)

Strong coupled organic-inorganic microcavities device has been realized and studied. One of the two cavities contains an organic thin film of tetrakis(4-methoxyphenyl)porphyrin, whereas the other microcavity is a dielectric structure coupled to the organic one by means of a LiF/ZnS Bragg mirror. Reflectivity spectra show the presence of two well defined cavity dips. We observe an energy splitting of the two cavity-modes. Despite only one cavity contains the active layer, the photoluminescence spectra display two peaks at the same energy of the reflectivity dips. These observations indicate the strong coupling of the two cavities. The comparison of the diagonalized effective Hamiltonian with the observed resonances further confirms the strong coupling.

Science.gov (United States)

This invention is an improved solar energy cavity receiver for exposing materials and components to high temperatures. The receiver includes a housing having an internal reflective surface defining a cavity and having an inlet for admitting solar radiation thereto. A photothermal absorber is positioned in the cavity to receive radiation from the inlet. A reflective baffle is positioned between the absorber and the inlet to severely restrict the re-radiation of energy through the inlet. The front surface of the baffle defines a narrow annulus with the internal reflective surface of the housing. The front surface of the baffle is contoured to reflect incoming radiation onto the internal surface of the housing, from which it is reflected through the annulus and onto the front surface of the absorber. The back surface of the baffle intercepts infrared radiation from the front of the absorber. With this arrangement, a high ...

International Nuclear Information System (INIS)

The bandwidth of LIGO-like terrestrial interferometric gravitational wave detectors is set by the pole of the Fabry-Perot cavities within the arms of the Michelson interferometer. This constraint arises because the gain of gravitational wave-induced signal sidebands is limited to frequencies within the linewidth of the cavities. The nature of standard Fabry-Perot cavities is such that one cannot independently adjust for increased gain without suffering a loss of bandwidth. If these quantities could be decoupled, the resulting improvement in bandwidth may lead to viable high frequency detectors. A pair of anti-parallel diffraction gratings within a Fabry-Perot cavity can increase the bandwidth of a LIGO-scale detector by a factor of #approx#1000.

International Nuclear Information System (INIS)

Polycrystalline specimens of spinel (MgAl_2O_4) and alumina (Al_2O_3) were irradiated at room temperature and 650deg C with either dual- or triple-ion beams in order to investigate the effects of simultaneous displacement damage and helium implantation on cavity formation. The cavities in alumina were aligned along the direction of the c-axis, with diameters ranging from < 2 to 10 nm. The cavities in spinel were preferentially associated with dislocation loops and were of similar size as the cavities in alumina. Catastrophic amounts of cavitation were observed at the grain boundaries in spinel when the displacement damage level exceeded a critical value (#approx =# 20 dpa) in the presence of a fusion-relevant (#approx =# 60 appm/dpa) helium environment. (orig.).

Energy Technology Data Exchange (ETDEWEB)

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent ...

Energy Technology Data Exchange (ETDEWEB)

The FEL electron linac consists of three buncher cavities: two accelerator cavities and a deflection cavity, each with its own phase-coherent rf source. All sources will be pulsed for 100 ..mu..s at a 1-pps rate. The phase and amplitude stability requirements are +-1/2/sup 0/, and +-1/2%. There are two subharmonic bunchers, each requiring 5 kW at 108.33 MHz. All remaining cavities operate at 1300 MHz. The fundamental buncher requires 5 kW, whereas each of the accelerating cavities requires at least 3 MW. The deflection cavity requires up to 100 kW, which is coupled from one of the accelerator cavity rf sources. Prominent features of the rf system are the phase and amplitude control circuits and the multimegawatt klystron amplifiers. Three L3707 klystrons were obtained from the AMRAD radar site at White Sands, which was decommissioned in the ...

International Nuclear Information System (INIS)

The FEL electron linac consists of three buncher cavities: two accelerator cavities and a deflection cavity, each with its own phase-coherent rf source. All sources will be pulsed for 100 #mu#s at a 1-pps rate. The phase and amplitude stability requirements are + or - 1/2"0, and + or - 1/2%. There are two subharmonic bunchers, each requiring 5 kW at 108.33 MHz. All remaining cavities operate at 1300 MHz. The fundamental buncher requires 5 kW, whereas each of the accelerating cavities requires at least 3 MW. The deflection cavity requires up to 100 kW, which is coupled from one of the accelerator cavity rf sources. Prominent features of the rf system are the phase and amplitude control circuits and the multimegawatt klystron amplifiers. Three L3707 klystrons were obtained from the AMRAD radar site at White Sands, which was decommissioned in ...

Energy Technology Data Exchange (ETDEWEB)

With an objective to discuss applicability of resistivity imaging using electromagnetic migration to detection of underground cavity, an applicability test was carried out on calculation of a numerical model and measurement data. By using the numerical model, a calculation was performed on a hypothetical case that a cubic cavity with sides each at 40 m exists in a homogenous medium of 200 ohm-m, with the cavity top located 20 m below the ground surface. As a result, it was possible to structure in a very short calculation time an image of the cavity which cannot be identified by one-dimensional inverse analysis. In the case of this cavity, a center of the image was structured on its lower face. It was shown that a location to indicate the image must be changed according to difference in the measurement locations. In a test on data measured in an underground ...

Energy Technology Data Exchange (ETDEWEB)

The mortality in undrained abdominal abscesses is high with a mortality rate ranging between 45 and 100%. The outcome in abdominal abscesses, however, has improved due to advances in image guided percutaneous interventional techniques. The main indications for the catheter drainage include treatment or palliation of sepsis associated with an infected fluid collection, and alleviation of the symptoms that may be caused by fluid collections by virtue of their size, like pancreatic pseudocele or lymphocele. The single liver abscesses may be drained with ultrasound guidance only, whereas the multiple abscesses usually require computed tomography (CT) guidance and placement of multiple catheters. The pancreatic abscesses are generally drained routinely and urgently. Non-infected pancreatic pseudocysts may be simply observed unless they are symptomatic or cause problems such as pain or obstruction of the biliary or the gastrointestinal tract. ...

Energy Technology Data Exchange (ETDEWEB)

A rare case of primary splenic cyst is shown in a young woman who had a left subcostal abdominal pain. Abdominal echography and CT scan revealed a cyst of the anterior aspect of the spleen. A sorologic test for hidatic disease was negative. On the basis of a presumed diagnostic of nonparasitic cyst, the patient was referred to a laparoscopic decapsulation with excision of the cysts wall not covered by splenic tissue. The patient was discharged 24 hours later. Histological report revealed epidermoid cyst. The laparoscopic approach has being recently considered an effective and less invasive alternative in the treatment of splenic diseases. We demonstrated that it should be considered for the treatment of splenic cysts present in a superficial location, with the advantage of organ preservation. (author)

British Library Electronic Table of Contents (United Kingdom)

Objectives Our purpose was to evaluate interaction of green tea consumption and abdominal obesity as related factors for lacunar infarction in Korean women. Designs A hospital-based, incident case-control study. Settings The Prevention and Managements of Stroke in Women study. Participants Cases (n=233) of first incident lacunar infarction were enrolled and matched by age to stroke-free hospital controls (n=204). Measurements The data were collected through face-to-face interviews by well trained research assistants to assess demographic, medical, lifestyle, marital status, religions status, green tea consumptions, family history of stroke, smoking status, alcohol consumption, meat and vegetable intake frequency, and past history of hypertension. Biochemical analysis, fasting blood specime...

International Nuclear Information System (INIS)

Intra-arterial subtraction angiography(IADSA) using Fuji computed radiography(FCR) was performed on 130 patients with cervical, pelvic, peripheral and abdominal diseases. It was compared with conventional angiography(radiographs produced by combining photographic film with an intensifying screen) performed on same patients. Radiographs produced by FCR were better than conventional radiographs in cervical, pelvic and peripheral angiography. In the abdominal angiography using FCR, there was misregistration artifact in some cases, but in hepatic angiography, the new radiographs under the injection of small amount of contrast medium(about 10ml) and the short exposure duration(about 10 seconds) were excellent. It was as valuable as conventional angiography (infusion hepatic angiography) for diagnosing hepatic neoplasms. (author).

Energy Technology Data Exchange (ETDEWEB)

Superconducting rf cavities are increasingly used in accelerators. Gradient is a parameter of particular importance for the ILC. Much progress in gradient has been made over the past decade, overcoming problems of multipacting, field emission, and breakdown triggered by surface impurities. However, the quenching limit of the surface magnetic field for niobium remains a hard limitation on cavity fields sustainable with this technology. Further exploration of materials and preparation may offer a path to surpassing the current limit. For this purpose, we have designed a resonant test cavity. One wall of the cavity is formed by a flat sample of superconducting material; the rest of the cavity is copper or niobium. The H field on the sample wall is 75% higher than on any other surface. Multipacting is avoided by use of a mode with no surface electric field. The ...

Energy Technology Data Exchange (ETDEWEB)

Swirling flow in a direct injection diesel engine was measured by a laser doppler velocimeter. Piston cavity diameter and top clearance volume were changed as factors affecting swirling flow to study the distribution of swirling flow speed. When using the same intake port and changing the opening ratio of piston cavity, the distribution of swirling flow speed was different by the cavity during intake process but these agree just after opening intake valve and then become again different by cavity. When increasing top clearance and decreasing compression ratio, the axial symmetry of flow during commpression process increases. When changing piston cavity, and also when changing intake port, the mean swirling ratio in inside and outside areas of combustion chamber has common tendency to increase and decrease respectively. The mean swirling flow in the combustion chamber may be capable ...

Energy Technology Data Exchange (ETDEWEB)

Operating the Stanford Linear Collider (SLC) at 120Hz repetition rate requires the presence of two bunches in both the electron and the positron damping ring. The {pi}-mode instability, a coupled bunch instability where the two bunches oscillate with a phase difference of 180{degrees}, had been observed in both rings with low current thresholds of 7{sup *}10{sup 9} particles per bunch. To avoid the instability, the RF system had to be operated in ways which in general reduced the cavity gap voltages and required constant operational attention. For the 1992 running cycle a passive cavity was installed and successfully tested. It is tuned to the frequency of the lower synchrotron oscillation sideband of an odd revolution harmonic. The impedance of the cavity then damps {pi}-mode oscillations very similar to the Robinson damping provided by the main RF cavities which damps O-mode synchrotron oscillations. ...

Energy Technology Data Exchange (ETDEWEB)

A simple theory for predicting the convective energy loss from side-facing cavity receivers in windless environments has been developed. The approach used is to determine the velocity distribution of the incoming air in the aperture plane (and thereby the rate of mass entrainment); and then to estimate the bulk temperature of the heated emerging air. The convective loss is then calculated from an energy balance. To illustrate this theory, numerical results applicable to the 2.15 meter cubic cavity being tested in the laboratory are provided.

International Nuclear Information System (INIS)

Excitation of the HF electric field in the local plasma resonance region (LPRR) of inhomogeneous plasma by pumping electric field or modulated electron beam results to appearance of the ponderomotive force that presses plasma out of this region. Density cavity is formed in the LPRR due to this field. Further dynamics in this region depends on the plasma properties. For plasma with hot electrons ion-acoustic pulses run away from the cavity. at the local density maximum the new peak of electric field is excited. It results to the formation of new density cavity, etc. For isothermal plasma the density jump is formed.

Energy Technology Data Exchange (ETDEWEB)

Numerical analysis of solar dish modified cavity receiver with Cone, CPC and Trumpet reflectors is presented. Three-dimensional modeling is carried out to estimate the convective and radiative heat loss from the receiver for different angles of inclination and operating temperatures. Incorporating reflectors in the modified cavity receiver for second stage concentration, the natural convection heat losses are reduced by 29.23, 19.81 and 19.16%, respectively. The receiver with the trumpet reflector has shown better performance as compared to other configurations. (orig.)

International Nuclear Information System (INIS)

We develop a new cavity with a mode similar to TE13 to produce microwave plasma, named APMPS II, which is able to produce a mass of air plasma with diameter of around 6 cm, equipped with about 3 kW input power under one atmosphere. The plasma seems to be homogeneous without significant filamentous discharge as observed by common camera device. We present the theory of this cavity, show the distribution of electric field of several planes inside the cavity and give some experimental results. (authors)

Science.gov (United States)

The authors report on temperature dependent characteristics and single mode performance of one-wave cavity, planar implanted, AlGaInP-based vertical-cavity surface emitting lasers. By optimizing the overlap between the gain peak and the cavity mode of the structure, they demonstrate record device performance, including 8.2 mW maximum output power and 11% power conversion efficiency for multimode operation and 1.9 mW and 9.6% power conversion efficiency for single mode operation at 687 nm. Improved performance at elevated temperatures is also achieved, with 1.5 mW output power demonstrated at 50 C from a 15-{micro}m-diameter device.

Energy Technology Data Exchange (ETDEWEB)

A new theory has been developed to calculate the steady state temperature profile in a cylindrical sample positioned along the entire axis of a cylindrical microwave cavity. Temperature profiles were computed for alumina rods of various radii contained in a cavity excited in one of the TM{sub 0n0} modes with n = 1, 2 or 3. Calculations were also performed with a concentric outer cylindrical tube surrounding the rod to investigate hybrid treating. The parametric studies of the total sample center and surface temperatures were performed as a function of the total power transmitted into the cavity. Also, the total hemispherical emissivity was varied at boundaries of the rod, surrounding tube, and cavity walls. The results are discussed in the context of controlling the average rod temperature and the temperature distribution in the rod during microwave processing.

Energy Technology Data Exchange (ETDEWEB)

This invention is comprised of an improved combustion system for an internal combustion engine is disclosed wherein a rich air/fuel mixture is furnished at high pressure to one or more jet plume generator cavities adjacent to a cylinder and then injected through one or more orifices from the cavities into the head space of the cylinder to form one or more turbulent jet plumes in the head space of the cylinder prior to ignition of the rich air/fuel mixture in the cavity of the jet plume generator. The portion of the rich air/fuel mixture remaining in the cavity of the generator is then ignited to provide a secondary jet, comprising incomplete combustion products which are injected into the cylinder to initiate combustion in the already formed turbulent jet plume. Formation of the turbulent jet plume in the head space of the cylinder prior to ignition has been found to yield a higher maximum combustion ...

Science.gov (United States)

... A technique of the prior art uses an acousto-optic Q-switch which can ... Another approach uses electro-optic Q-switches in a pseudo cavity dumping ...

Science.gov (United States)

... CLOSURE DURING HOT WORKING OF AN ALPHA/BETA TITANIUM ALLOY (PREPRINT) ... HOT WORKING OF AN ALPHA/BETA TITANIUM ALLOY ...

Science.gov (United States)

For the efficient operation of a cavity ringdown spectroscopy (CRDS) system utilized with a continuous-wave (cw) laser, we numerically analyze the coupling efficiency of a cw laser to a ringdown cavity in terms of changes in the scanning rate, the laser linewidth, and the mirror reflectivity. We also demonstrate a new simple design for a CRDS system that can produce a CRDS signal with only a piezoelectric transducer (PZT), without the acousto-optic modulator that is usually adopted to switch off the cw laser beam that enters the cavity. Furthermore, we investigate the feasibility of the cw CRDS technique with a fast-scanning PZT by recording a CRDS spectrum of acetylene overtones. The detection sensitivity that corresponds to the noise-equivalent absorption is found to be approximately 3 x 10(-9)/cm. PMID:18305817

Energy Technology Data Exchange (ETDEWEB)

A new principle of particle trapping in the simple spherical cavity using both electric and magnetic components of radiofrequency electromagnetic field is proposed. The electric component of H {sub 12} oscillating mode drives the fast particle oscillations, while the magnetic component synchronously bends the trajectories to the cavity center. A specially developed theory of particle stability predicts dense and energetic electron cluster in the trap. Numerical simulations of particle dynamics in the complete electromagnetic field taking into account both space charge and particle-induced magnetic field are in good agreement with the analytic results, giving a density of 2.6*10{sup 1} electrons/cm{sup 3} and an average kinetic energy of around 30 keV at an operating frequency of 3 GHz. Being used at lower frequency, spherical cavity can trap protons and heavier ions too, but with lower density and kinetic energy.

International Nuclear Information System (INIS)

A very simple theoretical scheme is proposed to implement two- and three-qubit controlled-phase gates firstly only using a single resonant interaction between ladder-type three-level atoms and the single-mode cavity. In the presented protocol, the quantum information is encoded on the stable ground states of the atoms (as the controlling qubits) and the zero- and one-photon Fock states of cavity-field (as the target qubit). Under the influence of the atomic spontaneous emission, the decay of the cavity-mode, and deviation of the coupling strength, the three-qubit controlled-phase gate may have a comparatively high fidelity. The experimental feasibility of controlled-phase gate and the case that is extended to realize N-qubit controlled-phase gate are also discussed. (general)

Energy Technology Data Exchange (ETDEWEB)

As an alternative to surgery, endovascular therapy with stent grafts has become the second main treatment option for infrarenal abdominal aortic aneurysms. Unlike surgery, endovascular treatment with stent grafts is also applicable in patients unfit for open repair. Despite current improvements in endovascular repair devices, significant anatomic barriers still exclude this technique for a large number of patients. Computed tomography, magnetic resonance imaging, and ultrasound are essential for diagnostics, preintervention planning, and postintervention follow-up of abdominal aneurysms treated with stent grafts. This review covers etiology, pathology, and diagnostic aspects. Materials and methods for endovascular treatment of abdominal aortic aneurysms are presented in detail, and clinical results and complications are discussed. (orig.) [German] Die endovaskulaere Therapie des infrarenalen Bauchaortenaneurysmas hat sich ...

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Ileal dysgenesis is an uncommon condition of unknown etiology occurring in the distal ileum in the region of the vitelline duct. The CT appearance of this lesion, although not previously described to our knowledge, is characteristic. We report a patient with ileal dysgenesis who had an abdominal CT scan to evaluate chronic iron deficiency anemia and protein-losing enteropathy. Recognition of this lesion by pediatric radiologists is important; so that surgical treatment, which is simple and effective, can be initiated quickly. (orig.)

International Nuclear Information System (INIS)

The wavelength dependence of the threshold in an InGaP-InAlGaP vertical cavity surface emitting laser is investigated using a microscopic theory of the semiconductor gain medium. Good agreement is found between experiment and theory for the minimum threshold lasing wavelength for a range of laser structures.

Energy Technology Data Exchange (ETDEWEB)

A solar unit is described which contains a cavity radiation receiver, parabolic-cylindrical concentrator, and reflector arranged between the radiation receiver and the concentrator symmetrically in relation to the optical plane of the latter. In order to expand the range of use, it contains a pair of flat mirrors with 2 working surfaces installed at an angle and symmetrically to the optical plane of the parabolic cylindrical concentrator between them and the reflector, while the latter is made in the form of 2 flat mirrors installed at an angle on the cavity radiation receiver.

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Thermal absorption with its combined thermal and mechanical loads in a solar receiver does depend significantly on the distribution of incident solar radiation. For a cavity receiver with paraboloid collectar a method is derived which enables the calculation of solar radiation distribution on the areas inside the receiver. The theoretical bases are presented first, and a subsequent example shows the influence of the most important geometric parameters on the distribution of solar radiation.

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A summary is provided of the first of three years of experimental and theoretical research on free-forced convection flows in cavity-type solar receivers. New experimental and theoretical results are presented and discussed. The implication of these findings, with respect to the future thrust of the research program, is clarified as well as is possible at the present time. Following various related conclusions a summary and tentative schedule of work projected for year two of research are presented.

International Nuclear Information System (INIS)

We present and characterize an experimental system in which we achieve the integration of an ultrahigh finesse optical cavity with a Bose-Einstein condensate (BEC). The conceptually novel design of the apparatus for the production of BECs features nested vacuum chambers and an in vacuo magnetic transport configuration. It grants large scale spatial access to the BEC for samples and probes via a modular and exchangeable ''science platform.'' We are able to produce 87Rb condensates of 5x106 atoms and to output couple continuous atom lasers. The cavity is mounted on the science platform on top of a vibration isolation system. The optical cavity works in the strong coupling regime of cavity quantum electrodynamics and serves as a quantum optical detector for single atoms. This system enables us to study atom optics on a single particle level and to further develop the field of quantum atom optics. We ...

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An investigation of natural convection losses from cavity-type solar central receivers is described and results are given. The approach followed was that of a fundamental experimental study in a simple cavity subject to well controlled boundary conditions. The Laser Doppler Velocimeter proved to be a useful technique to measure the velocity profiles associated with natural convection. Visualization techniques provided an understanding of the general behavior of the flow, particularly in three dimensional experiments. Experiments on systems of high Rayleigh numbers are described. (LEW)

International Nuclear Information System (INIS)

A critical issues study of a symmetric illumination, direct drive laser fusion reactor called SIRIUS has been conducted. In particular, the uniformity requirements for direct drive targets have been assessed and it is shown that respectable gains (more than 60) could be obtained at modest (2MJ) KrF laser energies. Previous ICF cavity designs have been examined for use in a symmetric illumination geometry and features from several designs have been combined into a dry wall cavity design with a radius of 8 meters. Neutronic and photonic analysis shows that the present SIRIUS cavity design can breed sufficient tritium (breeding ratio = 1.17) even with 32 laser ports penetrating the cavity. However, it was found that there are a few critical issues that remain to be solved before a self-consistent reactor design could be initiated. Radiation damage to final optics, thermal performance of SiC tiles on the ...

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A numerical simulation of two-dimensional laminar natural convection in a fully open tilted square cavity with an isothermally heated back wall is conducted. The remaining two walls of the cavity are adiabatic. Steady-state solutions are presented for Grashof numbers between 10{sup 2} and 10{sup 5} and for tilt angles ranging from {minus}60{degree} to 90{degree} (where 90{degree} represents a cavity with the opening facing down). The fluid properties are assumed to be constant except for the density variation with temperature that gives rise to the buoyancy forces, which is treated by the Boussinesq approximation. The fluid concerned is air with Prandtl number fixed at 0.71. The governing equations are expressed in a normalized primitive variables formulation. Numerical predictions of the velocity and temperature fields are obtained using the finite-volume-based power law (SIMPLER: Semi-Implicit Method for Pressure-Linked ...

British Library Electronic Table of Contents (United Kingdom)

We fabricate a low noise erbium-doped fiber ring laser that can be continuously tuned over 102nm by insertion of the fiber Fabry-Perot tunable filter (FFP-TF) in the ring cavity with a novel cavity structure and the optimal gain medium length. As an application of this fiber ring laser, we performed the absorption spectroscopy of acetylene (13C2H2) and hydrogen cyanide (H13C14N) and measure the absorption spectra of more than 50 transition lines of these gases with an excellent signal to noise ratio (SNR). The pressure broadening coefficients of four acetylene transition lines are obtained using this fiber ring laser and an external cavity laser diode.

International Nuclear Information System (INIS)

A compact storage ring NIJI-IV free electron laser (FEL) is being developed as a tunable light source which covers a wide wavelength range from the VUV to the IR. To shorten the FEL wavelength in the VUV region, the optical cavity mirror was improved and the original loss of Al_2O_3/SiO_2 multilayer mirror around 195nm was decreased 30% compared with that of the previous one. New optical cavity system equipped with two remotely interchangeable mirrors was installed for the UV/VUV FEL to stabilize the laser and also to extend the tuning range. As for construction of the IR FEL, modification of the beam transport system to make space for installation of the optical cavity was completed. (author)

CERN Document Server

The generation and control of quantum states of light constitute fundamental tasks in cavity quantum electrodynamics (QED). The superconducting realization of cavity QED, circuit QED, enables on-chip microwave photonics, where superconducting qubits control and measure individual photon states. A long-standing issue in cavity QED is the coherent transfer of photons between two or more resonators. Here, we use circuit QED to implement a three-resonator architecture on a single chip, where the resonators are interconnected by two superconducting phase qubits. We use this circuit to shuffle one- and two-photon Fock states between the three resonators, and demonstrate qubit-mediated vacuum Rabi swaps between two resonators. This illustrates the potential for using multi-resonator circuits as photon quantum registries and for creating multipartite entanglement between delocalized bosonic modes.

Energy Technology Data Exchange (ETDEWEB)

A numerical investigation for forced convection in a constant-temperature parallel plate channel with porous cavity and block alternately emplaced on the bottom plate is presented in this work. The Brinkman-Forchheimer-extended Darcy model, which accounts for the effects of impermeable boundary and inertia, is used to characterize the flow field inside the porous region. Solutions of the coupled governing equations are carried out through the stream function-vorticity analysis. The characteristics of fluid flow and forced convection heat transfer have been obtained by the examinations of various governing parameters, such as the Reynolds number, Darcy number, inertial parameter, Prandtl number, and two geometric parameters. Several interesting phenomena such as the heat transfer augmentation in the channel were presented and discussed. The results of this investigation indicate that the size of recirculation caused by porous block will have a profound effect on the ...

CERN Document Server

We investigate the behavior of a circuit QED device when the resonator is initially populated with a mesoscopic coherent field. The strong coupling between the cavity and the qubit produces an entangled state involving mesoscopic quasi-pointer states with respect to cavity dissipation. The overlap of the associated field components results in collapse and revivals for the Rabi oscillation. Although qubit relaxation and dephasing do not preserve these states, a simple analytical description of the dissipative dynamics of the circuit QED device including cavity relaxation as well as qubit dissipation is obtained from the Monte-Carlo approach. Explicit predictions for the spontaneous and induced Rabi oscillation signals are derived and sucessfully compared with exact calculations. We show that these interesting effects could be observed with a 10 photon field in forthcoming circuit QED experiments.

Science.gov (United States)

We report the characteristics of visible vertical cavity surface emitting laser diodes. Wafers are grown such that the Fabry--Perot resonance wavelength changes with position from 690 to 620 nm, overlapping to varying degrees with the [ital n]=1 and [ital n]=2 quantum well gain peaks at [similar to]670 and 650 nm. Gain guided devices are tested across the entire wafer, and pulsed room temperature lasing is observed from 634.6 to 663.2 nm. Our results suggest that gain contributions from the second quantized state are required to overcome high cavity losses in order to achieve lasing.

International Nuclear Information System (INIS)

Continuous ambulatory peritoneal dialysis (CAPD) is a generally well-tolerated treatment. However, some patients exhibit such complications as to prevent the continuation of treatment. Peritonitis is the major problem, but the continuation of treatment may also be undermined by different complications, such as peritoneal leakage, hernia, catheter malfunctioning, and scrotal-penile edema; a careful investigation of the patient is always needed in such cases. From November 1985 to February 1990, we examined 20 patients, who had presented with different types of complications in the course of dialysis. Peritoneography demonstrated 3 cases of abdominal hernias, 2 cases of patency of the peritoneal-vaginal duct, and 2 cases of catheter obstruction. Peritoneal CT allowed the identification of leakage in 3 patients, while the combined use of the two techniques showed adhesions or pathologic peritoneal recesses in 7 cases. In 3 patients normal patterns were observed. ...

International Nuclear Information System (INIS)

The objective of this study was to develop a method for 3D subtraction CT angiography and to optimize the visualization after semiautomatic segmentation. Ten patients with aneurysms of the abdominal aorta were examined using spiral CT. To reconstruct the vessels, as well as adjacent organs such as the liver and kidneys, one image data volume was acquired before and after injection of the contrast agent. The CT scans were obtained with a Siemens Somatom Plus 4. To improve the results of automatic segmentation, as well as visualization by maximum intensity projection (i.e. removal of bony structures), subtraction of both image volumes is necessary. However, small translation shifts disturb the subtraction process and produce artificial contours. To calculate the disparities along the three coordinate axes of two corresponding image volumes, a cepstrum filter is applied to a pair of image volumes. After detection of the disparities, which manifest as bright spots, the ...

British Library Electronic Table of Contents (United Kingdom)

Peripheral primitive neuroectodermal tumors (peripheral PNETs) are rare in the abdomen. We report the imaging findings of four peripheral PNETs arising in the abdomen. Three were ill-demarcated tumors and one was a well-demarcated tumor, with extensive local invasion and lymph node metastasis in two cases, respectively. The tumors are of inhomogeneous attenuation and heterogeneous enhancement after intravenous administration of contrast materials. Although their imaging manifestations cannot distinguish them from other sarcomas, recognition of these imaging features may be helpful in suggesting the possibility of peripheral PNETs in some cases.

International Nuclear Information System (INIS)

Computed tomography (CT) has already proved extremely effective both in cerebral and abdominal pathology. Several recent publications describing first heterogeneous series [1, 2, 7, 11-17], then studies of a single type of lesion [3-6, 8] have illustrated its usefulness in the study of bone lesions. This report deals with 41 cases of Ewing's sarcoma studied by CT at the Institut Gustave Roussy from October 1977 to July 1981, and tries to show both the limitations and indications of this technique for the diagnosis, treatment, and follow-up of Ewing's sarcoma as well as in the diagnosis of any eventual recurrence. (orig.).

British Library Electronic Table of Contents (United Kingdom)

Anesthetic techniques vary widely in the endovascular repair of abdominal aortic aneurysms (EVAR). Previous studies have demonstrated the feasibility of using local anesthesia. However, the ideal anesthetic technique has not been determined. This study examines whether anesthesic technique influences the outcomes of EVAR. Data regarding demographics, risk factors, procedural characteristics, recovery characteristics, treatment complications, acute ( 0.05, ANOVA). From these results we concluded that EVAR with local anesthesia is a safe and efficacious method that may reduce recovery times and postoperative medical morbidity compared to use of genera1 or spinal/epidural anesthesia.

Science.gov (United States)

Asymptomatic cholelithiasis is increasingly diagnosed today, mainly as a result of the widespread use of abdominal ultrasonography for the evaluation of patients for unrelated or vague abdominal complaints. About 10-20% of people in most western countries have gallstones, and among them 50-70% are asymptomatic at the time of diagnosis. Asymptomatic gallstone disease has a benign natural course; the progression of asymptomatic to symptomatic disease is relatively low, ranging from 10-25%. The majority of patients rarely develop gallstone-related complications without first having at least one episode of biliary pain ("colic"). In the prelaparoscopy era, (open) cholecystectomy was generally performed for symptomatic disease. The minimally invasive laparoscopic cholecystectomy refueled the discussion about the optimal management of asymptomatic cholelithiasis. Despite some controversy, most authors agree that the vast majority of subjects should ...

International Nuclear Information System (INIS)

CT of the gastrointestinal tract is commonly performed after administration of a high-density diluted iodinated oral contrast material. However, because if inadequate mixing of the contrast material with the gastrointestinal contents, pseudotumor and poor mucosal visualization are frequently shown on abdominal CT. To overcome these problem, 10% corn oil emulsion (COE) is tested as an alternative oral contrast agent in 40 patients. We analyse patients tolerance, gastric mucosal visualization and discrimination of pancreas from the duodenal C-loop to 10% COE in 40 patients compared with those obtained from 35 patients, who was received high-density diluted iodinated oral contrast agent (gastrografin). The results are as follows : 1. Patients' tolerance to 10% COE is similar to that to conventional oral contrast agent. 2. Image of the gastric mucosa from patients receiving 10% COE is superior to that receiving oral contrast agent. 3. The discrimination between ...

Science.gov (United States)

Thermal Cavity Receivers,". JPL. Publication. 83-97,. 1983. 5Hall, III, C.A., Glakpe, E.K., Cannon,. J.N., and. Kerslake,. T.W., "Modeling ...

International Nuclear Information System (INIS)

Malignant tumors of the sinonasal cavities are rare and often diagnosed late in the course of the disease. These tumors can extend into regions such as the orbit and brain, where treatment is difficult. Ten patients with non treated sinonasal malignant neoplasms and radiological evidence of tumor extension into the orbit and brain were studied with computed tomography. Five (50%) tumors were epithelial neoplasms whereas squamous cell carcinoma was the most common type (3 cases). The ethmoidal sinus was the most common site of origin of the tumors (40%), followed by the maxillary sinus (30%) and nasal cavity (30%). A total of 16 orbits were involved since 6 patients (60%) had bilateral orbital involvement. The tumors extended more often into the orbits through erosion of the medial and inferior orbital bones. All orbital compartments were involved in the majority of the orbits. Tumoral extension into the cranial cavity was ...

Science.gov (United States)

... biological effects of electromagnetic fields (EMFs) produced by high-voltage transmission lines have come under intense scrutiny, mostly with respect ... biological effects of electromagnetic fields (EMFs...

Energy Technology Data Exchange (ETDEWEB)

The authors investigate the optimisation of solar-heated cavity receivers in which solar energy collected by a paraboloid collector is converted into electrical energy. The focussed solar energy enters the receiver through an aperture to heat the working fluid, which flows inside the receiver tubes and is compressed by the compressor of a gas turbine system, to the highest process temperature. A method of calculating the distribution on the inner receiver surfaces of the solar radiation reflected by the paraboloid collector is presented to begin with. The interchange of radiant energy inside the receiver cavity can be calculated on this basis, including the radiation loads, the temperatures of the inner receiver walls, and the radiative and convective losses. The temperature fields in the tube walls must be known for determining the strength required of receiver tubes; they can be derived from the useful heat which comprises a directed ...

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For supersonic plasma flow velocities, instead of the usual shelf-step profile seen for subsonic flow, an overdense bump and cavity is observed. The profile is stable for long times even for moderate power microwaves.

Science.gov (United States)

A modified epitaxial design leads to straightforward implementation of short (1{lambda}) optical cavities and the use of C as the sole {ital p}-type dopant in AlGaInP/AlGaAs red vertical-cavity surface-emitting lasers (VCSELs). Red VCSELs fabricated into simple etched air posts operate continuous wave at room temperature at wavelengths between 670 and 690 nm, with a peak output power as high as 2.4 mW at 690 nm, threshold voltage of 2.2 V, and peak wallplug efficiency of 9%. These values are all significant improvements over previous results achieved in the same geometry with an extended optical cavity epitaxial design. The improved performance is due primarily to reduced optical losses and improved current constriction and dopant stability. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

UK PubMed Central (United Kingdom)

The delicate mesothelial surfaces of the pleural space and other serosal cavities slide relative to each, lubricated by pleural fluid. In the absence of breathing motion, differences between...Full Text Available

International Nuclear Information System (INIS)

In a positive polarity induction adder each of the induction cavities is a cathode, which emits electrons at a unique potential. These broad spectrum electrons strongly affect Magnetically Insulated Transmission Line (MITL) behavior. Electron flow decreases the cavity-to-MITL coupling efficiency, and reduces the power transport efficiency along the system. Also, the operating impedance of the MITL is lowered, reducing the diode impedance required for good coupling and good total system power efficiency. It is therefore imperative to understand the details of MITL electron flow. In previous work, measurement of MITL electron flow for a twenty-stage linear induction adder (Hermes III), operated in positive polarity, was compared with simulations. There was qualitative agreement, but some differences were noted. For example, measured electron flow in the first cavities was greater than in the simulations. The authors have ...

British Library Electronic Table of Contents (United Kingdom)

ObjectivesThe aim of this study was to evaluate the relationship between micro-tensile bond strength (mTBS) and ultimate tensile strength (UTS) of resin composite restorations in cavities filled by a bulk or incremental technique using the micro-tensile test.MethodsClass I cavities (4mm long, 3mm wide, 3mm deep) were prepared into dentine of sixteen human molars. All cavities were bonded with Clearfil SE Bond and restored with AP-X composite with either a bulk or incremental technique. After storage in water for 24h, the teeth were vertically sectioned to yield two slabs. Each slab was sectioned into three sticks. Sticks of one slab were trimmed into an hourglass of 0.7mm2 area at resin-dentine interface for bond strength measurement while the other sticks were trimmed at the centre of the...

Science.gov (United States)

A schematic of the Bench cavity receiver system is given, and the primary objectives, schedule and research plan for each of four tests are discussed. The tests are: (1) cold flow testing to functionally check all valves and their response using high pressure nitrogen gas; (2) a hot checkout to simulate both steady state and transient flux inputs to the receiver which are expected at the French facility; (3) basic performance using solar energy at the French facility; and (4) ir radiant heat testing. (LEW)

Energy Technology Data Exchange (ETDEWEB)

RADSOLVER is a computer program which calculates the radiation energy transport in cavity type receivers having an arbitrary number of apertures through which collimated beams of solar radiation enter. In contrast to the common assumption of gray (or semi-gray) surfaces used in the modeling of radiation transport, RADSOLVER accounts for the wavelength-dependence of emission, absorption and reflection with a band model of the radiative properties. It is intended that this report serve both as an instruction manual for the use of the RADSOLVER code and a vehicle for presenting the underlying theory. Illustrative examples along with input and output are presented.

British Library Electronic Table of Contents (United Kingdom)

The Monte Carlo ray-tracing method is applied and coupled with optical properties to predict the radiation performance of solar concentrator/cavity receiver systems. Several different cavity geometries are compared on the radiation performance. A flux density distribution measurement system for dish parabolic concentrators is developed. The contours of the flux distribution for target placements at different distances from the dish vertex of a solar concentrator are taken by using an indirect method with a Lambert and a charge coupled device (CCD) camera. Further, the measured flux distributions are compared with a Monte Carlo-predicted distribution. The results can be a valuable reference for the design and assemblage of the solar collector system.

Energy Technology Data Exchange (ETDEWEB)

An improved hybrid solar/combustion powered receiver of the type having an insulated housing with a front end and a rear end, a heat exchanger positioned adjacent the rear housing end for extracting heat energy out of the receiver, the insulated housing surrounding the heat exchanger and forming a receiver cavity, the housing also including an aperature having an aperture axis, the aperture located in the front housing end for admitting solar radiation to the cavity to impinge upon the heat exchanger, and a plurality of gas burners to provide combustion gases within the receiver.

Energy Technology Data Exchange (ETDEWEB)

The design of a solar heated cavity receiver transferring 60 MW of thermal energy to the working medium (air) for a closed-cycle gas turbine is described. The gas turbine plant with its cycle layout is presented. Then the tubes for the receiver are designed taking into account thermal and mechanical loads. It is shown how the occurring stresses are influenced by the destribution of the locally absorbed hat flux. Calculations for an existing coal fired air heater of a closed-cycle gas turbine give a first impression of the long-term behaviour to be expected of the receiver tubes.

Energy Technology Data Exchange (ETDEWEB)

Solar energy can be economically converted into electrical energy for small and medium power outputs. A typical solar power plant consists of a parabolic dish, cavity receiver and gas turbine. To obtain high gas turbine efficiencies, the working fluid used has to be heated to high temperatures. This necessitates the use of expensive high-quality materials for the tubes in the receiver. This expense must be kept to a minimum. The present paper demonstrates how this aim can be achieved by meeting the so-called Bammert Criterion.

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In this study the authors examine the convective cooling provided by fluid trapped in the cavity between two consecutive rollers in a roller bearing. In order to calculate the steady-state temperature of the roller, the designer must know nor only the rolling-contact heat input received by the roller but also the convection cooling effect of the surrounding fluid. Until recently, this lateral convection cooling effect was modeled by assuming a certain (constant) heat transfer coefficient h at the roller surface, and then calculating the steady-state temperature distribution around the roller.

Energy Technology Data Exchange (ETDEWEB)

This progress report consists of an article, the abstract of which follows, and apparently the references and vita from a proposal. A review of perturbation diagnostics applied to microwave resonant cavity discharges is presented. The classical microwave perturbation technique examines the shift in the resonant frequency and cavity quality factor of the resonant cavity caused by low electron density discharges. However, modifications presented here allow the analysis to be applied to discharges with electron densities beyond the limit predicted by perturbation theory. An {open_quote}exact{close_quote} perturbation analysis is presented which models the discharge as a separate dielectric, thereby removing the restrictions on electron density imposed by the classical technique. The {open_quote}exact{close_quote} method also uses measurements of the shifts in the resonant conditions of the cavity. Thirdly, ...

International Nuclear Information System (INIS)

The swelling behavior which results from simulated fusion environment irradiation of Fe-10% Cr has been characterized with transmission electron microscopy. Specimens were bombarded at 850 K with: a ''triple-beam'' of He"+, D_2"+, and 4 MeV Fe"+"+ ions to 0.3, 1, 3, 10, 30, and 100 dpa (displacement per atom); a ''dual-beam'' of He"+ and 4 MeV Fe"+"+ ions to 30 and 100 dpa; and a ''single-beam'' of 4 MeV Fe"+"+ ions to 30 dpa. The helium and hydrogen injection rates were approx. =10 appm He/dpa and approx. =40 appm D/dpa. Cavities were observed for damage levels of 3 dpa and greater. The swelling was <0.1% for damage levels <30 dpa, but at 100 dpa, there was an increase in the swelling to 2.5% for the ''triple-beam'' irradiation and 1.2% for the ''dual-beam'' irradiation. The swelling rates between 30 and 100 dpa correlate well with calculated values assuming a steady-state swelling-rate regime has been reached. Calculations show the rapid ...

British Library Electronic Table of Contents (United Kingdom)

Abstract Aims: The aim of this study was to examine whether metabolic syndrome (MS) is associated with periodontitis in a representative sample of Korean adults, who were involved in the Fourth Korea National Health and Nutrition Examination Survey (KNHANES). Materials and Methods: A total of 7178 subjects over the age of 19 years who participated in KNHANES were examined. MS was defined as the definition proposed by the National Cholesterol Education Program Adult Treatment Panel III and the abdominal obesity cut-off line based on Korean Society for the Study of Obesity. The periodontal status was assessed by the Community Periodontal Index. Multivariate logistic regression analysis was carried out adjusting for the sociodemographics, oral health behaviours and status, and health behaviou...

British Library Electronic Table of Contents (United Kingdom)

Serotonin is an important signaling molecule involved in the control of feeding in flies and other animals. In this study, a potential neurohemal release site for serotonin and the effects of exogenous serotonin on protein feeding were examined in the black blow fly, Phormia regina. A dense network of varicose neural processes exhibiting serotonin-like immunoreactivity was identified on the dorsal region of the thoracico-abdominal ganglion in P. regina. This dorsal region of the central nervous system is a likely site for the release of serotonin into the hemolymph. Circulating serotonin may have multiple systemic effects on fly physiology, including modulating or regulating feeding related processes and diuresis. Injections of exogenous serotonin reduced protein meal size in female flies ...

British Library Electronic Table of Contents (United Kingdom)

Abstract. Scanning electron microscopy documentation of first instar Calliphora vicina Robineau-Desvoidy, Phormia regina (Meigen) and Lucilia illustris (Meigen) (Diptera: Calliphoridae) is presented for the first time, and the following morphological structures are documented: pseudocephalon; antenna; maxillary palpus; facial mask; labial lobe; thoracic and abdominal spinulation; spiracular field; posterior spiracles, and anal pad. Light microscopy documentation and illustrations are provided for the cephaloskeleton in lateral and ventral views. New diagnostic features are revealed in the configuration of the facial mask, cephaloskeleton and posterior spiracles. The first instar morphology of C. vicina, Ph. regina and L. illustris is discussed in the light of existing knowledge about early...

British Library Electronic Table of Contents (United Kingdom)

Abstract Introduction: Transduodenal ampullectomy (TDA) can be performed for benign and premalignant tumors of the ampulla of Vater (AOV) as an alternative to pancreaticoduodenectomy. However, the laparoscopic approach has rarely been attempted. In this report 2 cases of benign ampullary tumor that were treated by totally laparoscopic TDA. Patients and Methods: Case 1 was of a 75-year-old female who was admitted with left knee pain and underwent arthroscopic debridement. On postoperative day 6, she showed elevated levels of alkaline phosphatase, aspirate aminotransferase, alanine transaminase, and gamma-glutamyl transpeptidase, without any other laboratory test abnormality. She had no complaint of abdominal pain, and physical examinations were unremarkable. Computed tomography (CT), magnet...

British Library Electronic Table of Contents (United Kingdom)

Exposure to urban air pollution is an independent risk factor for increased cardiovascular diseases. Heat shock protein 70 (HSP70) has been implicated in the pathogenesis of vascular dysfunction and cardiovascular diseases. This study has been designed to determine whether inhalation of urban air induces HSP70 expression in the lung and blood as well as the association of HSP70 and air pollution-induced vascular dysfunction. Apolipoprotein E (Apo-E) deficient mice were exposed to diesel exhaust (DE) either acutely (3 days, 200 or 400 g/m3 for 6 h/day) or chronically (7 weeks, 200 or 400 g/m3 for 6 h/day). HSP70 was measured in the lung using immunohistochemistry, and in the plasma by ELISA. Abdominal aorta rings were used to determine vascular functional responses. Chronic DE-exposure incr...

British Library Electronic Table of Contents (United Kingdom)

Background For the past 14 years, we have been performing laparoscopic adrenalectomy via the lateral transabdominal as well as the posterior retroperitoneal approach. The aim of this study is to describe patient selection criteria for each approach with comparison of perioperative outcomes. Methods In patients with smaller tumors, low body mass index (BMI), history of previous abdominal operations, appropriate body habitus, and bilateral pathology, we have performed preferentially the posterior approach. Data regarding clinical pathology, tumor size, BMI, estimated blood loss (EBL), operating time (OT), morbidity, mortality, and duration of stay were analyzed retrospectively. Data are expressed as mean +- standard error of the mean (SEM). Results One hundred seventy-two laparoscopic adrena...

International Nuclear Information System (INIS)

In Niigata University Hospital, most of conventional radiography were changed to Fuji computed Radiography (FCR) from July 1988. To evaluate its clinical utility, questionnaires relating to FCR image were distributed to all physicians including non-radiologists in the hospital after three months. The ratio of the physicians evaluated FCR image to be better than conventional image was 75% in chest radiography, 64% in abdominal radiography. FCR tomography of bone, joint, cranium and chest was also evaluated to be better than conventional by most of the physicians. Reduced size of the film and difficulty in detecting interstitial shadows of the lung were mentioned to be the fault of FCR. (author).

Energy Technology Data Exchange (ETDEWEB)

Aim of the work was to describe computerised tomography (CT) findings of calcified renal metastases focusing on differential diagnosis problems. Abdominal CT scans of 8000 patients with tumor, performed from 1984 to 1998, have been retrospectively reviewed. [Italian] Scopo del lavoro e' quello di descrivere gli aspetti con tomografia computerizzata delle metastasi renali calcificate enfatizzando le problematiche diagnostico differenziali. Sono state valutate retrospettivamente le indagini TC addominali di 8000 pazienti affetti da tumore nel periodo 1984-1998, analizzando le lesioni calcificate riscontrate.

British Library Electronic Table of Contents (United Kingdom)

Pyogenic sacroiliitis is a rare entity in children. Diagnosis is often delayed because of its variable clinical presentation, low suspicion by the examining physician, and rare findings on radiographs. Delayed diagnosis, however, results in complications such as iliopsoas abscess. We report the case of a 12-year-old girl hospitalized with a 21-day history of fever, pain in the left iliac fossa, and flexion contracture of the hip. On examination, she had fever (38.9 ^oC), psoitis, localized tenderness at the left sacroiliac joint, and pain elicited by lateral compression of the pelvis. The abdominal examination was normal. The erythrocyte sedimentation rate was 130mm in the first hour, C-reactive protein was 186mg/l, and the white blood cell count was 18,400/mm^3, with 79% neutrophils. Urin...

Energy Technology Data Exchange (ETDEWEB)

To investigate the possibility of using HOM signals induced in SC cavities as beam and cavity diagnostics, narrow band (20 MHz) data was recorded around the strong TE111-6(6{pi}/9-like) dipole modes (1.7 GHz) in the 40 L-band (1.3 GHz) cavities at the DESY TTF facility. The analyses of these data have so far focused on using a Singular Value Decomposition (SVD) technique to correlate the signals with each other and data from conventional BPMs to show the dipole signals provide an alternate means of measuring the beam trajectory. However, these analyses do not extract the modal information (i.e., frequencies and Q's of the nearly degenerate horizontal and vertical modes). In this paper, we described a method to fit the signal frequency spectrum to obtain this information, and then use the resulting mode amplitudes and phases together with conventional BPM data to determine the mode polarizations and relative centers ...

Energy Technology Data Exchange (ETDEWEB)

Experimental investigations are being conducted on a single-cylinder direct-injection diesel engine to examine the effects of combustion chamber specifications and swirl ratios on the heat release and transient heat transfer characteristics. Heat rejection was examined on the basis of heat release calculations using cylinder pressure time histories. Transient surface temperature data obtained from stationary locations in the piston and cylinder head were used as the basis for determining the transient heat flux rates. The results showed good agreement with the heat rejection calculated from cylinder pressure data and that transient heat flux in a piston cavity was reduced with the larger cavity diameter and a higher swirl ratio. On the other hand, a transient heat flux in a piston head was not changed by the cavity diameter and swirl ratio. 5 refs., 19 figs.

Energy Technology Data Exchange (ETDEWEB)

The standing-wave free-electron laser (FEL) differs from a conventional linear-wiggler microwave FEL in using irises along the wiggler to form a series of standing-wave cavities and in reaccelerating the beam between cavities to maintain the average energy. The device has been proposed for use in a two-beam accelerator (TBA) because microwave power can be extracted more effectively than from a traveling-wave FEL. The standing-wave FEL is modeled in the continuum limit by a set of equations describing the coupling of a one-dimensional beam to a TE{sub 01} rectangular-waveguide mode. Analytic calculations and numerical simulations are used to determine the time variation of the reacceleration field and the prebunching required so that the final microwave energy is the same in all cavities. The microwave energy and phase are found to be insensitive to modest spreads in the beam energy and phase and to errors in the ...

Energy Technology Data Exchange (ETDEWEB)

Stable and accurate numerical analytical method even at high Rayleigh numbers is desired, and in addition flexibility and economical efficiency are very important for numerical analysis. Unsteady flows of natural convention in a square cavity are investigated using the GSMAC (generalized and simplified marker and cell) finite-element method at high Rayleigh numbers from 10 {sup 6} to 10 {sup 8}. Validities of the multi-pass algorithm and BTD (balancing tensor diffusivity), which are highly accurate solutions for finite-element method, are investigated by introducing them to the GSMAC finite-element method. As the result, it was found that the multi-pass algorithm has little effect for the GSMAC finite-element method. The steady solutions at the Rayleigh numbers of 10 {sup 5} and 10 {sup 7} agreed well with the bench mark solutions and numerical solutions. Complex transient phenomena at Rayleigh numbers higher than 10 {sup 7} are successfully observed. 12 refs., 11 ...

International Nuclear Information System (INIS)

The authors have designed and constructed four types of electron-beam diodes for the new 4-MV RLA injector: a non-immersed foilless diode, a magnetically immersed foilless diode, a foil diode and an ion-focused foilless diode, They are tailored to fit the new injector cavity. The design goals were to produce high quality 10-kA to 20-kA electron beams with a #beta# perpendicular smaller than 0.2 and a beam radius of the order of 2 cm. These beams will be matched to the RLA IFR channel so #beta# perpendicular must be equal to or smaller than the square root of the ratio of the beam current versus Alfven current for f_e = 1. A reentrant anode geometry was selected for the injector cavity design, because it offers substantial savings on the required amount of feromagnetic cores. The inner radius of the outside shell, now only 30 cm, would have been twice as large (60 cm) if a coaxial non-reentrant geometry had been adopted. The shape of the anode ...

CERN Document Server

We propose an innovative linear accelerating structure, particularly suited for hadrontherapy applications. Its two main features are compactness and good power efficiency at low beam velocities: the first is achieved through a high working frequency and a consequent high accelerating gradient, the second is obtained by coupling several H-mode cavities together. The structure is called CLUSTER, which stands for "Coupled-cavity Linac USing Transverse Electric Radial field". In order to compare the performance of this structure with other hadrontherapy linac designs involving high frequencies, a conceptual study has been performed for an operating frequency of 3 GHz. Moreover a proof of principle has been obtained through RF measurements on a prototype operating at 1 GHz. An accelerator complex using a CLUSTER linac is also considered for protontherapy purposes. The whole complex is called cyclinac and is composed of a commercial cyclotron ...

Energy Technology Data Exchange (ETDEWEB)

The collaboration between the Los Alamos National Laboratory and the National Bureau of Standards (NBS), started in 1979, has led to the development of an advanced c-w microtron accelerator design. The four 2380-MHz NBS accelerating structures, containing a total of 184 accelerating cavities, have been fabricated and delivered. New fabrication methods, coupled with refinements of hydrogen-furnace brazing techniques described in this paper, allow efficient production of side-coupled structures. Success with the NBS RTM led to Los Alamos efforts on similar 2450-MHz accelerators for the microtron accelerator operated by the Nuclear Physics Department of the University of Illinois. Two accelerators (each with 17 cavities) have been fabricated; in 1986, a 45-cavity accelerator is being fabricated by private industry with some assistance from Los Alamos. Further private industry experience and refinement of the described ...

Energy Technology Data Exchange (ETDEWEB)

Youngkwang Unit 3,4 and Ulchin Unit 3 and 4 have had problem of the KSNP Steam Generator due to a severe fretting wear on the tube. In particular, the wears were localized and concentrated in the upper part of U-bend of the Central Cavity region. At the upper tube bundle Central Cavity, the fluid flow velocities and void fraction are very high, because the steam is made by high heat transfer at secondary region. Also, this region is affected easily by fretting wear due to it's unsupported span is longer than another regions. The fretting wear is assumed to be result of Flow-Induced Vibration (F. I. V), which can occur by many mechanisms. EFDP was added to UCN 5,6 for prevent fretting wear by the SEC LCC and DSHIC, a company of design and manufacture of the steam generator, respectively. In order to evaluate the efficacy of EFDP, ANSYS and ATHOS-3 Code were used. From sensitivity analysis and calculation results, Density and Velocity ...

Energy Technology Data Exchange (ETDEWEB)

The Neutron Science Project at Japan Atomic Energy Research Institute has been proposed for the research of nuclear transmutation technology and the basic science with a spallation neutron source. The project calls for an 8MW proton linac which accelerates 5.3mA average current cw and pulsed beams up to 1.5GeV. The superconducting (SC) rf-cavity is the main option for the energy part from 100MeV to 1.5GeV because by using the SC structure, less power is consumed in cw operation than by using a normal conducting (NC) structure. A conceptual design study of the superconducting proton linac is reported. The SC linac is composed of 8 {beta} sections. Each section has the identical 5-cell cavities with the surface peak field of 16MV/m. The total number of cavities is 284, and the length of the SC linac is 690m. The lattice design is determined with the equipartitioned condition and the matched envelope equations for the minimum ...

Energy Technology Data Exchange (ETDEWEB)

Silica microspheres were deposited into two-dimensional periodic arrays and coated with a thin layer of silicon nanocrystals. The luminescence from the silicon nanocrystals coupled into the whispering gallery modes of the spheres, with Q factors that depended on a range of parameters including sphere size, position on the sphere, viewing direction, and thickness of the nanocrystal coating. Scattering from the film-sphere and/or the sphere-substrate contacts resulted in a lower Q for modes that intersect these regions. The highest Q factors obtained in this work were {approx}1500. The results suggest that silica microspheres may be promising candidates for high-Q cavities that incorporate silicon nanocrystals for cavity QED or nonlinear optical effects.

International Nuclear Information System (INIS)

A numerical and experimental investigation is carried out in a solar thermochemical reactor for the thermal dissociation of ZnO at 2000 K using concentrated solar energy. The reactor consists of a cavity-receiver lined with ZnO particles and directly exposed to high-flux irradiation. A transient heat transfer model is formulated to link the rate of radiation, convection, and conduction heat transfer to the reaction kinetics. The radiosity and Monte Carlo methods are applied to obtain the distribution of net radiative fluxes at the internal surfaces of the reactor cavity and at the surface of the ZnO bed. Validation is accomplished in terms of the calculated and measured transient temperature profiles and chemical reaction rates.

Energy Technology Data Exchange (ETDEWEB)

A free-electron laser (FEL) two-beam accelerator (TBA) is proposed, in which the FEL interaction takes place in a series of drive cavities, rather than in a waveguide. Each drive cavity is 'beat-coupled' to a section of the accelerating structure. This standing-wave TBA is investigated theoretically and numerically, with analyses included of microwave extraction, growth of the FEL signal through saturation, equilibrium longitudinal beam dynamics following saturation, and sensitivity of the microwave amplitude and phase to errors in current and energy. It is found that phase errors due to current jitter are substantially reduced from previous versions of the TBA. Analytic scalings and numerical simulations are used to obtain an illustrative TBA parameter set.

Energy Technology Data Exchange (ETDEWEB)

This paper describes in an apparatus for absorbing a beam of concentrated solar energy and which includes a cavity receiver with an inlet for transmission thereinto of solar radiation, a protective apertured shield means about the inlet. It comprises: rigid support means fixed to the periphery of the inlet and projecting radially inwardly therefrom to define a generally central aperture area through which the solar radiation can pass into the cavity receiver; and non-structural blanket means spread over the rigid support means between the periphery of the inlet and the aperture area, the material having a high temperature capability and providing for infra-red radiation insulation, while remaining relatively cool when subjected to solar radiation.

International Nuclear Information System (INIS)

The buoyancy driven convective flow fields are steady circulatory flows which were made between surfaces maintained at two fixed temperatures. They are ubiquitous in nature and play an important role in many engineering applications. Especially, in last decades, natural convection in a close loop or cavity becomes the main issue in the molecular biology for the polymerase chain reaction (PCR). Application of a natural convection can reduce the costs and efforts remarkably. This paper focuses on the sensitivity study of turbulence analysis using CFD for a natural convection in a closed rectangular cavity. Using commercial CFD code, FLUENT, various turbulent models were applied to the turbulent flow. Results from each CFD model will be compared each other in the viewpoints of flow characteristics. This work will suggest the best turbulent model of CFD for analyzing turbulent flows of the natural convection in an enclosure system.

Energy Technology Data Exchange (ETDEWEB)

We report the lasing characteristics of gain-guided AlGaInP/AlGaAs visible vertical-cavity surface-emitting laser diodes. At room temperature, continuous-wave operation is achieved over the wavelength range of 657--685 nm with the minimum threshold current at 670 nm. Devices with a 10-[mu]m diameter have threshold currents as low as 1.25 mA at room temperature (297 K) and 0.8 mA at 250 K. In addition, a single predetermined linear polarization state is found, independent of the lasing mode order and operating temperature.

British Library Electronic Table of Contents (United Kingdom)

This study addresses the solar thermal decomposition of natural gas for the co-production of hydrogen, as well as Carbon Black as a high-value nano-material, with the bonus of zero CO2 emissions. The work focused on the development of a medium-scale solar reactor (10kW) based on the concept of indirect heating. The solar reactor is composed of a cubic cavity receiver (20cm side), which absorbs concentrated solar irradiation through a quartz window via a 9cm-diameter aperture. The reacting gas flows inside four graphite tubular reaction zones that are settled vertically inside the cavity. Experimental results were as follows: methane conversion and hydrogen yield of up to 98% and 90%, respectively, were achieved at 1770K, and acetylene was the most important by-product, with a mole fraction...

British Library Electronic Table of Contents (United Kingdom)

Glycyrrhizin is a triterpene glycoside, a major active constituent of licorice (Glycyrrhiza glabra) root and numerous pharmacological effects like anti-inflammatory, anti-viral, anti-tumour and hepatoprotective activities has been attributed to it. In this study we evaluated the anti-inflammatory activities of glycyrrhizin in mice model of acute inflammation, carrageenan-induced pleurisy. We report here that glycyrrhizin (given at 10mg/kg i.p. 5min prior to carrageenan) exerts potent anti-inflammatory effects in this model. Injection of carrageenan into the pleural cavity of mice elicited an acute inflammatory response characterized by fluid accumulation in the pleural cavity which contained a large number of neutrophils (PMNs) as well as an infiltration of PMNs in lung tissues and subsequ...

International Nuclear Information System (INIS)

Mini-LIA is a miniature of a linear induction accelerator developed by China Academy of Engineering Physics and Tsinghua University in 2007. It has been constructed with a thermionic cathode in an electron injector and a metglas core in the induction accelerator cavities. A double-pulsed electron beam was produced for the first time in China on the Mini-LIA with a thermionic cathode in the electron gun and a metglas core in the induction accelerator cavities. A double-pulsed beam current of more than 1.1A was obtained on condition of 80 kV double-pulsed high voltage produced by pulsed power system supplying to the injector and accelerating modules. Some primary experiments for measuring the parameters of Mini-LIA has been performed, and some beam characterizations of Mini-LIA are presented. Further improvement is underway. (authors)

British Library Electronic Table of Contents (United Kingdom)

The Formula Not Shown system of Formula Not Shown was first observed in auroral emissions by Meinel in 1950. Although the Formula Not Shown band system has been reinvestigated since this first spectral study, no laboratory spectrum of the (2,1) vibronic band has been obtained. We have recently built a continuous-wave cavity ringdown spectrometer, and as a first test of this spectrometer we observed the (2,1) band of Formula Not Shown in a positive column discharge cell. Many lines of the first positive band system of Formula Not Shown were also identified during the process of assigning this spectrum. The relative intensities of the Formula Not Shown and Formula Not Shown bands were found to change with discharge cell pressure, and so each spectral region was observed at two pressures to a...

Energy Technology Data Exchange (ETDEWEB)

We describe a fully automated bead puller system which uses stepping motors to position the bead, and an HP-8510 network analyzer to measure the resulting frequency shifts, both devices being under computer control. Longitudinal motion of the bead is used for measurement of cavity shunt impedance. In addition, azimuthal scans at fixed longitudinal position aid in determining the multipole character of higher-order modes. High sensitivity/accuracy is made possible by measuring phase shifts at the unperturbed resonant frequencies (rather than frequency shifts themselves), thereby permitting averaging factors of > 500 with only modest increases in data acquisition time. Sample measurements will be presented. A comprehensive analysis of the experimental results is presented in an accompanying paper.

International Nuclear Information System (INIS)

Stimulated bremsstrahlung in an undulating electric field in the lasing beam direction (electric wiggler) was shown to be possible from the quantum- mechanical viewpoint. Herein, this possibility is scrutinized from the viewpoint of classical electrodynamics. It is found that if stimulated bremsstrahlung in a transverse undulating magnetic field (magnetic wiggler) occurs, stimulated bremsstrahlung in the electric wiggler must also occur. We further show that a free electron laser (FEL) using a magnetic wiggler to provide a catalyzer field for stimulated bremsstrahlung cannot serve as a practical FEL operating in the soft x-ray region from both theoretical and experimental viewpoints. On the other hand, the authors demonstrate that the FEL using a traveling wake field in a two-beam elliptical pill-box cavity is well suited as a source of coherent radiation in the soft x-ray region.

Energy Technology Data Exchange (ETDEWEB)

To assess the influence of stent design [interlacing (type A) vs. crossing method (type B)] on neointimal hyperplasia using a self-expandable nitinol stent, which crosses the side branches of the abdominal aorta. In seven mongrel dogs, nitinol stents with type A and B intersections were placed in the abdominal aorta across the main branches: 4 Niti-Ms and 3 Niti-Ds. Two months after the stent placement, a DSA was performed for a stent patency evaluation, followed by the extraction of the aortas. The degree of neointimal formation along the wire was evaluated by calculating the area ratio of intimal hyperplasia (type A vs. B). A Student's t-test was employed to investigate the differences in the neointimal hyperplasia between blood types A and B. The total number of wire intersections overlain at the ostia branch ostia was 23 for type A and 36 for type B. The area ratio of the neointimal hyperplasia, for a given area, was 29.09 {+-} ...

International Nuclear Information System (INIS)

The advent of multislice spiral CT (MSCT) technique has led to new aspects of dose reduction, especially for the dedicated use of MSCT in children. Optimizing pediatric MSCT protocols according to the clinical problem allows reduction of radiation exposure to a minimum without loss of diagnostic quality. The different parameters that influence the degree of dose reduction, like tube current-time product (mAs), tube voltage (kV), collimation and pitch, are discussed in context with previously published data and our own experience in nearly 200 pediatric CT examinations. In our department, the effective mAs is calculated for a pediatric chest MSCT by multiplication of the body weight in kilogram with a factor of 1 to 1.5 and for a pediatric abdominal MSCT by multiplication with a factor of 2 to 2.5. To calculate the equivalent effective dose for a contrast media-enhanced 80 kV protocol, the effective mAs of the 120 kV protocol can be multiplied by 2.7. A factor less ...

Energy Technology Data Exchange (ETDEWEB)

Rectus sheath hematomas are a frequent but sometimes misdiagnosed disease in patients under anticoagulative drugs, hemodialysis, or simply in the elderly. The most frequent localization is in the lower part of the abdomen: the explanation lies in the anatomy of the abdominal wall, especially in the arcuate line of the rectus sheath. Aim of this work is to explain the reason of the almost constant location correlating the anatomy with the CT features. The rectus abdominis muscle lies between the aponeuroses of the transverse and oblique muscles which form the so called rectus sheath. This arrangement is found from the costal arch to a level approximately between the umbilicus and the pubic symphisis, where the rear layer of the rectus sheath ends with a curved edge, called the arcuate or semicircular line of Douglas. Beneath this line the aponeuroses of the three muscles pass in front of the rectus which is separated from the peritoneum only by the fascia ...

Energy Technology Data Exchange (ETDEWEB)

The conception of a solar receiver intended to equip a tower power-station has to combine multiple requirements: very highly concentrated solar flux, unsteady in time and space; necessity to obtain a high efficiency; respect of the physical limits of the materials and of the fluid. The description of Themis solar receiver and of its operation is preceded by considerations which have led to the choice of the cavity, of the fluid and of its circulation.

Energy Technology Data Exchange (ETDEWEB)

Malignant tumors of the sinonasal cavities are rare and often diagnosed late in the course of the disease. These tumors can extend into regions such as the orbit and brain, where treatment is difficult. Ten patients with non treated sinonasal malignant neoplasms and radiological evidence of tumor extension into the orbit and brain were studied with computed tomography. Five (50%) tumors were epithelial neoplasms whereas squamous cell carcinoma was the most common type (3 cases). The ethmoidal sinus was the most common site of origin of the tumors (40%), followed by the maxillary sinus (30%) and nasal cavity (30%). A total of 16 orbits were involved since 6 patients (60%) had bilateral orbital involvement. The tumors extended more often into the orbits through erosion of the medial and inferior orbital bones. All orbital compartments were involved in the majority of the orbits. Tumoral extension into the cranial cavity was ...

CERN Document Server

By using a laser and maser in tandem, it is possible to obtain laser action in the hot exhaust gases involved in heat engine operation. Such a "quantum afterburner" involves the internal quantum states of working gas atoms or molecules as well as the techniques of cavity quantum electrodynamics and is therefore in the domain of quantum thermodynamics. As an example, it is shown that Otto cycle engine performance can be improved beyond that of the "ideal" Otto heat engine.

Energy Technology Data Exchange (ETDEWEB)

We report the corrected intercomparison of the World Radiometer Reference (WRR) irradiance scale and the Electrotechnical Laboratory (ETL) spectral irradiance scale. In addition, we confirm the intercomparison precision using the test facility where the irradiance of ETL 500 W standard lamp can be measured directly with the cavity radiometer. The results showed that the irradiance based on the WRR scale was 0.5-0.7% lower than the one based on the ETL scale

Energy Technology Data Exchange (ETDEWEB)

An advanced ceramic dome cavity receiver is discussed which heats pressurized gas to temperatures above 1800/sup 0/F (1000/sup 0/C) for use in solar Brayton power systems of the dispersed receiver/dish or central receiver type. Optical, heat transfer, structural, and ceramic material design aspects of the receiver are reported and the development and experimental demonstration of a high-temperature seal between the pressurized gas and the high-temperature silicon carbide dome material is described.

Energy Technology Data Exchange (ETDEWEB)

The mainly nonstationary operation of a solar-heated receiver can be simulated with sufficient accuracy only if data about the dynamic behavior are available. For this reason, the dynamic behavior of a solar cavity receiver with parabolic dish collector is investigated. The development of a mathematical simulation considering heat transfer and storage processes is presented and the procedure for a numerical solution is illustrated. The performance of the calculation method is finally demonstrated by simulating the passage of a cloud.

Energy Technology Data Exchange (ETDEWEB)

The construction of networks consisting of optically interconnected processing units is a promising way to scale up quantum information processing systems. To store quantum information, single trapped atoms are among the most proven candidates. By placing them in high finesse optical resonators, a bidirectional information exchange between the atoms and photons becomes possible with, in principle, unit efficiency. Such an interface between stationary and ying qubits constitutes a possible node of a future quantum network. The results presented in this thesis demonstrate the prospects of a quantum interface consisting of a single atom trapped within the mode of a high-finesse optical cavity. In a two-step process, we distribute entanglement between the stored atom and two subsequently emitted single photons. The long atom trapping times achieved in the system together with the high photon collection efficiency of the cavity make the applied ...

Energy Technology Data Exchange (ETDEWEB)

Theoretical and experimental results of investigating a cylindrical heat receiver with secondary reflectors are presented. One important element of solar thermal power plants (STPP) is the heat receiver. Several forms of heat receiver exist; the main form is the heat receiver of cavity form (including cylindrical, rectangular, and cubic heat receivers with a noncircular aperture). The linear dimension of such heat receivers is equal to, or larger than, the theoretical diameter of the concentrator focal spot.

Energy Technology Data Exchange (ETDEWEB)

The development and experimental demonstration of a high-temperature seal for the SHARE ceramic dome cavity receiver is reported. The mechanical contact seal which was tested on one-foot-diameter silicon-carbide ceramic-dome hardware at pressure differentials to four atmospheres and dome temperatures to 2200/sup 0/F (1200/sup 0/C) showed negligible leakage at expected receiver operating conditions. Potential solar receiver applications for the technology are illustrated.

CERN Multimedia

L. to r.: C. Ruivet, J.F. Malo, A. Insomby, R. Romijn, J. Tuckmantel, E. Chiaveri, H. Lengeler, D. Bloess, W. Weingarten, H. Preis, P. Marchand and G. Cavallari

Science.gov (United States)

Of 1850 patients with cholelithiasis diagnosed in the past 17 years, 1116 female and 734 male, 598 patients (32.3%) presented with one or more of three major symptoms, i.e., abdominal pain, fever and jaundice, whereas the remainder (67.7%) had none of these symptoms. The proportion of the asymptomatic patients was similar in all age groups, being around 70%. Only 20 per cent of 680 asymptomatic patients, followed for 10 to 17 years (median 13.3 years), developed biliary symptoms. Older patients over 70 years of age had a higher rate of change to the symptomatic group, as compared with younger patients under 70, 29.5% vs. 19.3%, respectively. During this period, carcinoma of the gallbladder developed in one of the asymptomatic patients (0.1%). Oral dissolution therapy was successful in only 4.2 per cent of attempted cases and associated with a recurrence rate of as high as 20%. We conclude that asymptomatic gallstone patients should only be followed up by ultrasound ...

Energy Technology Data Exchange (ETDEWEB)

Between 1970 and 1981, 348 patients underwent definitive irradiation. Of these patients 6 (1.7 per cent) sustained severe rectal injury as manifest by major rectal bleeding, rectal stricture, rectal mucosal slough and rectal ulceration. Severe rectal injury was observed in 0 of 13 patients (0 per cent) treated with 125iodine, 3 of 329 (1 per cent) treated with 6,400 to 6,800 rad external irradiation, 2 of 39 (5 per cent) treated with 7,000 to 7,300 rad external irradiation, and 1 of 7 (14 per cent) treated with 198gold and external irradiation. The impact of radiation dose, radiation therapy technique and surgical trauma was assessed. Rectal injury was managed by supportive measures in 2 patients and by diverting colostomy in 3 with benefit. One patient underwent abdominoperineal resection. A small bowel fistula and an intra-abdominal abscess developed, and the patient died.

Science.gov (United States)

In mammals and insects, paracellular blood barriers isolate the nervous system from the rest of the animal. Glia and accessory cells of the nervous system use pumps, channels, cotransporters, and exchangers collectively to maintain the extracellular ion environment and osmotic balance in the nervous system. At present, the molecular mechanisms that regulate this process remain unclear. In humans, loss of extracellular ion and volume regulation in the nervous system poses serious health threats. Drosophila is a model genetic organism with a proven track record for uncovering molecular mechanisms relevant to human health and disease. Here, we review what is known about extracellular ion and volume regulation in larval abdominal nerves, present some new data about the impact of neural activity on the extracellular environment, and relate the findings to mammalian systems. Homologies have been found at the level of morphology, physiology, molecular mechanisms, and ...

Scientific Electronic Library Online (English)

Abstract in english INTRODUCTION: Treatment of the cryptorchid testicle is justified due to the increased risk of infertility and malignancy as well as the risk of testicular trauma and psychological stigma on patients and their parents. Approximately 20% of cryptorchid testicles are nonpalpable. In these cases, the videolaparoscopic technique is a useful alternative method for diagnosis and treatment. MATERIALS AND METHODS: We present data concerning 90 patients submitted to diagnostic lapa (more) roscopy for impalpable testicles. Forty-six patients (51.1%) had intra-abdominal gonads. In 25 testicles of 19 patients, we performed a two stage laparoscopic Fowler-Stephens orchiopexy. The other 27 patients underwent primary laparoscopic orchiopexy, in a total of 29 testicles. RESULTS: We obtained an overall 88% success rate with the 2 stage Fowler-Stephens approach and only 33% rate success using one stage Fowler-Stephens surgery with primary vascular ligature. There ...

Energy Technology Data Exchange (ETDEWEB)

Hepatobiliary scintigraphy is the only non-invasive technique providing real-time assessment of hepatocytes function and bile progression from the liver to the intestine; for this reason it is of great importance in the study of jaundice and many other disorders of the liver and the biliary tract in children. Ultrasonography is the initial method of evaluating the intra- and extrahepatic bile ducts dilatation: the differential diagnosis between biliary atresia and neonatal hepatitis cannot however be done without hepatobiliary scintigraphy. Cystic fibrosis patients also require hepatobiliary scintigraphy; liver and biliary tract disease can really occur independently of the underlying disease severity and the presence of steatorrhoea. Hepatobiliary imaging in children who have undergone liver transplantation is of major importance; it can assess vascularity, parenchymal function biliary drainage, possible presence of a bile leak and obstruction; it has very good sensitivity and ...

International Nuclear Information System (INIS)

Purpose: To evaluate contrast-enhanced CT scan in the diagnosis of intrahepatic cholangiocarcinoma by correlating the CT appearance with pathologic specimens. Materials and methods: Twenty-eight patients with pathologically proven intrahepatic cholangiocarcinoma were examined. Unenhanced abdominal CT study were performed in 28 patients; conventional contrast-enhanced CT in 27 patients. Enhanced CT scan including fast injection, fast scan and delayed scan at the largest section of the lesion was done in 7 patients. Contiguous 10 mm CT scans of the surgical specimens were also obtained in 8 patients. The preoperative and specimen CT scans in these 8 patients were compared with the corresponding pathological sections. A total of 103 areas of the pathological sections was compared with the CT appearances. Results: All lesions contained areas of delayed contrast enhancement and/or no enhancement on CT examinations. The areas of delayed contrast enhancement corresponded ...

International Nuclear Information System (INIS)

In portal images with high energy X-ray (10 MV), it is sometimes difficult to verify the irradiation field because of the low contrast. Especially, in the abdominal and pelvic region, the deterioration of portal image quality is remarkable. To solve this problem, we took portal images using computed radiography (FCR). Also, we develop a technique in which a copper plate (3 mm) and lead foil (0.3 mm) are closely set in the front and rear of the photostimulable phosphor plate (imaging plate), for increased energy absorption. As a result, image quality was very high and we confirmed image improvement using observer performance experiments. We made a special cassette which can closely set metallic plates to imaging plate and load FCR-7000 directly. Therefore, image process becomes simple, and suitable for routine work. In computed radiography, image processing (tone scale modification and edge enhancement) is possible, and is advantageous portal imaging. When PACS is ...

Science.gov (United States)

The knowledge of wound ballistics and of wounding mechanisms is mandatory for the radiologist to interpret the CT findings of gunshot wounds. The severity of a bullet wound depends on the characteristics of the tissue it goes through, i.e., tissue elasticity, density, thickness of the wounded body part, the type of tissue, its specific gravity, internal cohesiveness and anatomical relationships, as well as on missile characteristics, i.e., mass, shape, fragmentation and deformation. Bullet velocity is certainly a major factor in wounding, but it is only one factor. Two major wounding mechanisms exist the crushing of the bullet-struck tissue (forming the permanent cavity) and radial stretching (forming a temporary cavity). Bullet "yaw" is defined as the angle between the long axis of the bullet and its flight path. The yaw is directly proportional to tissue crushing and stretching: the wider the yaw, the most severe tissue crushing and ...

Energy Technology Data Exchange (ETDEWEB)

A new type of passive cooling system has been invented (Forsberg 1993): the Temperature-Initiated Passive Cooling System (TIPACS). The characteristics of the TIPACS potentially match requirements for an improved reactor-cavity-cooling system (RCCS) for the modular high-temperature gas-cooled reactor (MHTGR). This report is an initial evaluation of the TIPACS for the MHTGR with a Rankines (steam) power conversion cycle. Limited evaluations were made of applying the TIPACS to MHTGRs with reactor pressure vessel temperatures up to 450 C. These temperatures may occur in designs of Brayton cycle (gas turbine) and process heat MHTGRs. The report is structured as follows. Section 2 describes the containment cooling issues associated with the MHTGR and the requirements for such a cooling system. Section 3 describes TIPACS in nonmathematical terms. Section 4 describes TIPACS`s heat-removal capabilities. Section 5 analyzes the operation of the temperature-control mechanism ...

International Nuclear Information System (INIS)

The FEL rf system was designed for 3.6-MW rf pulses from two klystrons to drive two linacs and one deflection cavity at 1300 MHz. Two 108.33-MHz subharmonic buncher cavities and one fundamental buncher were also built, each powered by a 5-kW amplifier. A single phase-coherent source drives the various amplifiers as well as the grid of the electron gun, which is pulsed at 21.67 MHz. The initial buncher system did not work as well as expected, and the first linac tank required more rf power than anticipated. The light output was extremely sensitive to amplitude and phase errors. More powerful klystrons were developed and installed, and a method was discovered for operating a single subharmonic buncher and allowing the first linac to complete the bunching process. This paper shows the actual configuration used to operate the laser and discusses future improvements.

International Nuclear Information System (INIS)

Interaction of the internal states of an atom with spatially dependent standing-wave cavity field can impart position information of the atom passing through it leading to subwavelength atom localization. We recently demonstrated a different regime of atom localization [Phys. Rev. A 72, 013820 (2005)], namely sub-half-wavelength localization through phase control of electromagnetically induced transparency. This regime corresponds to extreme localization of atoms within a chosen half-wavelength region of the standing-wave cavity field. Here we present further investigation of the simplified model considered earlier and show interesting features of the proposal. We show how the model can be used to simulate a variety of energy-level schemes. Furthermore, the dressed-state analysis is employed to explain the emergence and suppression of the localization peaks, and the peak positions and widths. The range of parameters for obtaining clean ...

International Nuclear Information System (INIS)

The interferometric gravitational wave detector Virgo has successfully completed the first major step of its commissioning. It consists of a Michelson interferometer with 6 m arms with suspended mirrors. The interferometer is tuned to the dark fringe with a recycling mirror on the other port (bright fringe) to form an equivalent 12 m long Fabry-Perot cavity. This setup has allowed us to validate the major technology choices that have been made: passive seismic attenuators, a light source with a long mode cleaner, many analogue and digital servo loops, control software, high speed data acquisition system. A sensitivity of 8 x 10"-"1"7 m Hz"-"1"/"2 at 1 kHz together with a duty cycle of 80% has been attained during a 72 h engineering run. The data analysis allowed us to understand the noise contributions, and several improvements have been carried out while proceeding with the end of the installation of vacuum tubes and the remaining suspensions, and before starting ...

Energy Technology Data Exchange (ETDEWEB)

A prototype trumpet type nonimaging secondary concentrator was designed and fabricated for use with the Cummins Power Generation (CPG) 7.5 kW{sub e} dish-Stirling system. A set of operational tests was carried out with a high temperature heat pipe receiver and gas-gap calorimeter. These tests have successfully alleviated any operational concerns about the effectiveness of active water cooling for such devices. The authors obtained over two full days of testing with the cavity receiver operating at its design temperature of 660 C while the trumpet throat temperature remained {approx_equal} or less than 100 C. In addition, these tests have shown that the thermal isolation of the trumpet from the hot receiver is very effective. Highly variable insolation, instabilities in the temperature controller on the calorimeter, and a poor match between the optical quality of the primary and the design of the trumpet have made detailed quantitative results difficult to obtain.

International Nuclear Information System (INIS)

Differentiating a benign from a malignant lesion by information such as density data, or signal intensities or echo gradients, is not possible with CT, nor MRI, nor ultrasonography. Only some lesions show characteristic signs. Inflammations cannot be difscriminated from malignant tumors. CTs of small tumors in particular are so poor in contrast that it is much more difficult to detect tumors or discriminate them from other lesions, as compared to MR images or ultrasonographs. CT does not detect surface tumors, but is more sensitive than MRI or US in detecting discrete cortical bone lesions. The same applies to small calcified tumors. MRI however is most sensitive in detecting tumor volumes in the yellow marrow, and is the best modality for evaluation of extraossal extension of tumors. CT yields better results than MRI if applied for simultaneous screening of lymph node metastases in the lower neck. MRI frequently is spoilt by movement artefacts. High-resolution, contrast enhanced CT ...

CERN Document Server

Micron scale silicon nitride (SiNx) microdisk optical resonators fabricated on a silicon wafer are demonstrated with Q = 3.6 x 10^6 (finesse = 5 x 10^4) and an effective mode volume of 15 (\\lambda / n)^3 at wavelengths \\lambda ~ 852 nm resonant with the D2 transition manifold of cesium. A dilute hydrofluoric wet etch is shown to provide sensitive tuning of the microdisk optical resonances, and robust mounting of a fiber taper provides efficient fiber optic coupling to the SiNx microdisk cavities while allowing unfettered optical access for laser cooling and trapping of atoms. Initial measurement of a hybrid atom-cavity chip indicates that cesium adsorption on the surface of the SiNx microdisks results in significant red-detuning of the disk resonances. A technique for parallel integration of multiple (10) microdisks with a single optical fiber taper is also demonstrated.

International Nuclear Information System (INIS)

Distributed Bragg reflectors (DBRs) composed of In_0_._5Al_0_._5P/In_0_._5(Al_yGa_1_-_y)_0_._5P quarter-wave layers have been prepared using metalorganic vapor phase epitaxy. The structures were grown over a wide range of high-index layer composition (0#<=#y#<=#0.6) and peak reflectivity wavelength (720 nm#<=##lambda##<=#565 nm, covering the spectrum from deep red to green). In all cases observed and calculated reflectance spectra were in excellent agreement. Using these DBRs, an undoped all-phosphide visible vertical cavity surface-emitting laser structure was grown. Under pulsed optical excitation at room temperature, lasing was obtained at a wavelength of #lambda##approx#670 nm, with a threshold power density comparable to that observed from similar structures prepared using AlAs/AlGaAs DBRs.

Energy Technology Data Exchange (ETDEWEB)

Alloy 800 is an austenitic Fe-Ni-Cr steel containing relatively minor but important amounts of carbon, aluminium and titanium. Special grades of alloy 800 known as 800H, 800HT and 800LC differ in the concentrations of these elements. In addition to these industrial specifications, further melts were prepared containing phosphorous or sulphur. Using a radioactive tracer method the bulk and grain-boundary diffusion of {sup 59}Fe was investigated in these alloys in the temperature range 800 to 1000 C. For evaluation of the diffusion profiles the approximation of Suzuoka was used, which considers the depletion of the tracer on the surface. By autoradiography it was confirmed that such depletion occurs. In alloy 800H the activation energy of grain-boundary diffusion of {sup 59}Fe was found to be (209{+-}17) kJ/mol; dissolved elements, especially phosphorous, increase the activation energy. The same materials - aged at 800 C for 100 h - were used for creep experiments at 800 C under constant ...

Energy Technology Data Exchange (ETDEWEB)

Using a radioactive tracer method the bulk and grain boundary diffusion of {sup 59}Fe was determined in industrial alloy 800 and melts of alloy 800 with additional P and S in the temperature range 800 to 1000 C. The use of the approximation of Suzuoka was confirmed by autoradiographs. In alloy 800 H the activation energy of grain boundary diffusion of {sup 59}Fe is (209 {+-} 17)kJ/mol. Dissolved elements especially P increase the activation energy of the grain boundary diffusion of Fe by their segregation to the grain boundaries. In addition the influence of the grain boundary diffusion on the growth of creep cavities was investigated in the same materials, and the chemical composition of the creep cavities and grain boundaries were analysed by Auger electron spectroscopy (AES). For alloy 800 + 0.088 wt-%P an enrichment of about 14 at-%P was observed at the grain boundaries. The addition of P clearly enhances the creep strength of alloy 800; ...

Energy Technology Data Exchange (ETDEWEB)

The following work deals with the realization, characterization and modeling of GaInP / AlGaInP high power semiconductor laser diodes in the visible wavelength range. In addition to the exploration and optimization of efficiency, temperature stability and maximum output power of multi-mode lasers especially methods for longitudinal and lateral mode stabilization of high power laser diodes have been investigated. Although often the focus of optimization is on the threshold current density, in this work the performance of the laser diode for an operation point around 1 Watt under continous wave operation is regarded as the figure of merit. It turns out that low carrier densities are key for an efficient reduction of the heterobarrier leakage currents. In addition, large optical cavity structures with low internal losses enable high external quantum efficiencies even for long cavities. Finally high laser effiency as well as an efficient cooling ...

International Nuclear Information System (INIS)

In this paper the authors present a design study on the longitudinal dynamics of a relativistic klystron two-beam accelerator (RK-TBA) scheme which has been proposed as a power source candidate for a 1 TeV next linear collider (NLC). They address the issue of maintaining stable power output at desired level for a 300-m long TBA with 150 extraction cavities and present their simulation results to demonstrate that it can be achieved by inductively detuning the extraction cavities to counter the space charge debunching effect on the drive beam. They then carry out simulation study to show that the beam bunches desired by the RK-TBA can be efficiently obtained by first chopping an initially uniform beam of low energy into a train of beam bunches with modest longitudinal dimension and then using the open-quotes adiabatic captureclose quotes scheme to bunch and accelerate these beam bunches into tight bunches at the operating energy of the drive ...

Energy Technology Data Exchange (ETDEWEB)

The plasma plume generated by a new type of high energy Janitor known as the railplug, is examined. The railplug is a miniaturized railgun that has the potential for improving ignition characteristics of combustible mixtures in engines. The objective of the study is to gain an uderstanding of the characteristics of the plasma created by a transparent railplug, and to validate a multidimensional computer simulation of the plasma and shock fronts. The nature of the plume emitted by the railplug was examined for three levels of electrical energy while firing into air at a pressure of 1 atm. The computer model is to be used to predict trends in railplug performance for various railplug designs, energies, and ambient conditions. The velocity of the plasma movement inside a transparent railplug was measured, as well as the velocity of the plume ejected from the cavity. A shock is produced at the initiation point of the arc and propagates down the ...

British Library Electronic Table of Contents (United Kingdom)

This study addresses the solar thermal decomposition of natural gas for the co-production of hydrogen and carbon black (CB) as a high-value nano-material with the bonus of zero CO2 emission. The work focused on the development of a medium-scale solar reactor (10kW) based on the indirect heating concept. The solar reactor is composed of a cubic cavity receiver (20cm-side), which absorbs concentrated solar irradiation through a quartz window by a 9cm-diameter aperture. The reacting gas flows inside four graphite tubular reaction zones that are settled vertically inside the cavity. Experimental results in the temperature range 1740-2070K are presented: acetylene (C2H2) was the most important by-product with a mole fraction of up to about 7%, depending on the gas residence time. C2H2 content i...

Energy Technology Data Exchange (ETDEWEB)

We report a templated-synthetic approach based on apoferritin to prepare radionuclide nanoparticle (NP) conjugates. Non-radioactive yttrium (89Y) was used as model target and surrogate for radioyttrium (90Y) to prepare the nanoparticle conjugate. The center cavity and multiple channel structure of apoferritin offer a fast and facile method to precipitate yttrium phosphate by diffusing yttrium and phosphate ions into the cavity of apofrritin, resulting a core-shell nanocomposite. The yttrium phosphate/apoferritin nanoparticle was functionalized with biotin for further application. The synthesized nanoparticle was characterized by transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS). We found that the resulting nanoparticles were uniform in size, with a diameter of around 8 nm. We tested the pre-targeting capability of the biotin-modified yttrium phosphate/apoferritin nanoparticle (yttrium phosphate/apoferritin ...

British Library Electronic Table of Contents (United Kingdom)

We propose and demonstrate experimentally a singlelongitudinal-mode (SLM) fiber double-ring laser using an Erbium-doped waveguide amplifier (EDWA), polarization controller (PC), and a fiber Fabry-Perot tunable filter (FFP-TF) into the ring cavity. In addition, the output power, side-mode suppression ratio (SMSR), and the stabilities of power and wavelength of the laser also are investigated. (Copyright 2007 by Astro Ltd., Published exclusively by WILEY-VCH Verlag GmbH & Co. KGaA)

Energy Technology Data Exchange (ETDEWEB)

Solar heating of gas turbine plants steps back more and more into the focus of current research. The mainly instationary operation of solar turbine power plants can only be predicted with sufficient accuracy if the transient behaviour of the receiver for the solar radiation is known. Therefore the transient behaviour of cavity receivers of different design is investigated. The mathematical model used for the simulation of the heat transfer and energy storage processes is illustrated. Computed results for receivers with various inner lining are compared and evaluated concerning their use in practice.

Energy Technology Data Exchange (ETDEWEB)

Considerable potential exists for increasing the annual efficiency of line-focus collectors by reducing receiver heat losses. Five alternate receiver designs are compared with a standard design. The comparison is based on annual collector-field efficiency using optimized receiver designs. Of the receivers studied, the all-glass design and the cavity design provide the greatest increases in efficiency. Average fluid temperatures range from 200/sup 0/ to 450/sup 0/C. As a guide for further study, areas of uncertainty and potential problems are identified.

International Nuclear Information System (INIS)

Current effort of the TAMA project is focused on establishment of the interferometer operation with a new vibration isolation system, called 'Seismic Attenuation System' (SAS). The SAS employs a multiple stage structure to realize soft spring for all of directions, as well as utilizes active control systems to stabilize mechanical resonances in the low frequency region below 1 Hz. The SASs were installed for four test masses, resulting in improvement of cavity length fluctuation below 150 Hz. We describe the structure of the SAS and its local active control system, and the status of the interferometer.

International Nuclear Information System (INIS)

Periosteal Ewing's sarcoma is an uncommon, but well documented origin of this malignant condition with radiography signs, different from intramedullary growing tumours. Imaging modalities like CT or MRI supply proof of macroscopically intact endosteal cortical surface and free medullary cavity in long bones affected by this periosteal type of malignancy. Definite confirmation is valid after a careful microscopic investigation of the resected specimen. The prognosis of this type of Ewing's sarcoma may be favourable than that of the central type. Early diagnosis and therapy are thus essential. A clinical survey of six observations is given. (orig.).

Energy Technology Data Exchange (ETDEWEB)

This investigation concerns the nonlinear dynamics of heat transfer from a surface using an upstream eddy promoter. A numerical model is developed for the coupled fluid flow and heat transfer process based on a modified MacCormack scheme. Numerical simulations are carried out to determine the response and heat transfer enhancement due to the promoter. The average heat transfer from a cavity floor is seen to be increased by a factor of approximately five over the unpromoted'' flow. Another interesting feature of the study is the nonlinear viscous flow dynamics from the cylinder-wall interaction which differ significantly from the familiar cylinder-free stream patterns.

International Nuclear Information System (INIS)

Laser gain of the NIJI-IV compact storage-ring-based Free Electron Laser (FEL) system at AIST reached #approx#9% at 200 nm for an average beam current of 16.3 mA. In addition to such a drastic gain enhancement, improvement of the laser-cavity performance has led to successful FEL lasing in the vacuum ultraviolet below 200 nm even in a compact system. Temporal and spectral characteristics of the NIJI-IV FEL were examined around 200 nm. FEL performance will be briefly discussed from the application point of view.

DEFF Research Database (Denmark)

Axially symmetric waveguides, resonators, and scatterers of arbitrary cross section and anisotropy in the cross section can be modeled rigorously with use of 2-D Cartesian-grid based codes by means of mere redefinition of material permittivity and permeability profiles. The method is illustrated by the frequencydomain simulations of resonant modes in a circular-cylinder cavity with perfectly conducting walls, a shielded uniaxial anisotropic dielectric cylinder, and an open dielectric sphere for which, after proper implementation of the perfectly matched layer boundary conditions, the radiation quality factor is also determined.

British Library Electronic Table of Contents (United Kingdom)

This paper will track the design and results of an injection molding tool developed to manufacture microfluidic chips. The mold design and injection molding process was complicated by the presence of integrated capillary fluidic interconnects. We determined that design of the runner and gate system responsible for delivering molten plastic to the cavity had a significant impact on the quality of parts produced by the mold and the size of the process window. Numerical results confirm our findings that reducing gate lengths and increasing part thickness dramatically improved the filling profile and lowered injection pressures by 37%. Finally, the influence of gate location on part shrinkage is analyzed and discussed.

International Nuclear Information System (INIS)

The motivation for using a tandem electrostatic accelerator as an electron accelerator for a free electron laser (FEL) is presented. The adaptation of the HVEC EN tandem at the Weizmann Institute for this purpose, electron beam optics and nonlinear FEL computation relevant for this FEL realization are described. In the tandem configuration the terminal is held at a positive potential. The electron beam is accelerated from ground potential to the terminal in one beam tube and then decelerated down the other beam tube. The FEL wiggler and cavity are at the terminal. Due to the beam energy recovery this scheme produces a high power beam at the terminal with a small investment in electrical power. (orig.).

CERN Document Server

A cost effectively method to fabricate nanopores in silicon by only using the conventional wet-etching technique is developed in this research. The main concept of the proposed method is a two-step etching process, including a premier double-sided wet etching and a succeeding track-etching. A special fixture is designed to hold the pre-etched silicon wafer inside it such that the track-etching can be effectively carried out. An electrochemical system is employed to detect and record the ion diffusion current once the pre-etched cavities are etched into a through nanopore. Experimental results indicate that the proposed method can cost effectively fabricate nanopores in silicon.

Science.gov (United States)

We report the first visible (657 nm) vertical-cavity surface-emitting laser. The photopumped undoped structure was grown using low-pressure metalorganic vapor-phase epitaxy in a single-growth sequence on misoriented GaAs substrates. The optical cavity consists of an In{sub 0.54}Ga{sub 0.46}P/In{sub 0.48}(Al{sub 0.7}Ga{sub 0.3}){sub 0.52} P strained quantum-well active region and a lattice-matched In{sub 0.48}(Al{sub {ital y}}Ga{sub 1{minus}{ital y}}){sub 0.52} P (0.7{le}{ital y}{le}1.0) graded spacer region, while the distributed Bragg reflectors are composed of Al{sub 0.5}Ga{sub 0.5}As/AlAs quarter-wave stacks. Room-temperature optically pumped lasing was achieved with a very low-threshold power, clearly demonstrating the viability of this new technology. These results provide the foundation for visible semiconductor laser-diode arrays for a number of applications including laser projection displays, holographic memories, and plastic fiber ...

International Nuclear Information System (INIS)

The commercial Modular High Temperature Gas-Cooled Reactor (MHTGR) achieves improved reactor safety performance and reliability by utilizing an integrated sequence of completely passive thermal storage and heat transfer mechanisms to reject decay heat in the event that all its active cooling systems fail to operate. During such events, the initial heatup transient in the core is followed by a quasi-steady state cooldown process which, if uninterrupted, can continue for several days. A buoyancy-driven natural convection cooling system called the RCCS facilitates the continuous heat removal by circulating ambient air through the reactor cavity, where it is heated and then exhausted to the outside environment. The peak thermal load on the RCCS occurs approximately at the time that the vessel reaches its highest temperature. To confirm the adequacy of the RCCS design, detailed analytical models were developed to simulate the decay heat removal process and predict the ...

International Nuclear Information System (INIS)

The radiation-induced microstructural changes have been studied by cross-sectional transmission electron microscopy for single-crystal #alpha#-Al_2O_3 samples irradiated with triple ion beams (0.25 MeV H"+, 0.6 MeV He"+ and 2.4 MeV O"2"+; 'Triple (A)'), (0.33 MeV H"+, 0.45 MeV He"+ and 1.3 MeV O"+; 'Triple (B)') and three consecutive single ion beams (0.3 MeV H"+ ion followed by 0.6 MeV He"+ and then 0.8 MeV O"+ ions) at 650 C to doses in the range 0.1-8.4 dpa at the damage peak. In the specimen irradiated with Triple (A), having the same average projected range to a total peak dose of 3.7 dpa, cavities with an average diameter of 13 nm were formed between 1.2 and 1.75 #mu#m in depth causing a swelling of 0.1% at the peak, which is larger than those of the specimens irradiated with other conditions. The extent of the cavity-introduced region is some 40% smaller than observed in the damage region due to the He"+ and the O"+ ions and due to the ...

Energy Technology Data Exchange (ETDEWEB)

Recently there has been growth, in interest in non-equilibrium interaction of half-period long optical pulses with matter. To date the optical pulses have been produced by chopping out a half-period long segment from a longer pulse using a semiconductor switch driven by a femtosecond laser. In this paper we present new methods for producing tunable ultra-short optical pulses as short as half an optical period using a free-electron laser driven by electron bunches with a duration a fraction of an optical period. Two different methods relying on the production of coherent spontaneous emission will be described. In the first method we show that when a train of ultra-short optical pulses as short as one half period. We present calculations which show that the small signal gain is unimportant in the early stages of radiation build up in the cavity when the startup process is dominated by coherent spontaneous emission. To support our proposed method we present ...