Energy Technology Data Exchange (ETDEWEB)

[sup 123]I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy was performed in 20 diabetic patients (NIDDM) and 8 control subjects to investigate the association between clinical autonomic nerve dysfunction and myocardial accumulation of MIBG. We used coefficient variance of R-R interval (CV[sub R-R]) as a index of the autonomic neuropathy and categorized diabetes into two groups (CV[sub R-R][>=]2.0: non-autonomic neuropathy. CV[sub R-R]<2.0: autonomic neuropathy). In planar imaging studies, heart to mediastinum MIBG uptake ratio (H/M) was calculated on both early and delayed images. The washout ratio of [sup 123]I-MIBG in the heart (%WR) was also obtained using myocardial tracer activity on the both images. Mean value of these indices in diabetic group did not reveal any significant difference with the value in the control group. On the SPECT images, ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this paper is to investigate the influence of diabetic myocardial damage (suspected myocardial damage; SMD) diagnosed by [sup 201]Tl-SPECT and diabetic cardiac autonomic neuropathy (AN) on myocardial MIBG uptake in patients with NIDDM. Eighty-seven diabetic patients divided into four subgroups: 23 with SMD (+) AN (+); 19 with SMD (+) AN (-); 27 with SMD (-) AN (+); 18 with SMD (-) AN (-), and 10 controls were studied. Both planar and SPECT images were taken at 30 minutes (early) and 3 hours (delayed) after [sup 123]I-MIBG injection. The heart to mediastinum uptake ratio (H/M) and washout ratio of [sup 123]I-MIBG (WR) were obtained from both planar images. Similarly, the difference between the [sup 201]Tl image and the [sup 123]I-MIBG image in the total uptake score (TUS) was taken as ...

Science.gov (United States)

PMID:4410216

British Library Electronic Table of Contents (United Kingdom)

BackgroundWave reflection during the systole increases left ventricular (LV) pressure, tension-time index (TTI) and myocardial oxygen requirement. The purpose of this study was to extract that component of extra myocardial oxygen requirement that is due to early systolic wave reflection, define it as wasted effort (?Ew), and examine its relationship to LV hypertrophy (LVH).MethodsRadial artery pressure waveforms were recorded using applanation tonometry and central aortic waveforms generated in 98 patients with untreated hypertension. Aortic augmentation index (AIa), wave reflection amplitude (i.e., aortic augmented pressure (AG)) and systolic duration (ED?Tr), ejection duration (ED) and round-trip travel time of the pressure wave (Tr) were calculated from the aortic waveform, a...

International Nuclear Information System (INIS)

By means of neutron activation analysis, injured and adjacent uninjured human heart tissue from 12 autopsy cases with myocardial infarction are investigated with respect to the concentration of 23 trace elements. The bulk elements K, Na and P are also determined. A recently developed ion-exchange technique, combined with subsequent y-spectrometry, is used. The following trace elements are determined: Ag, As, Au, Ba, Br, Ca, Cd, Ce, Co, Cr, Cs, Cu, Fe, Hg, La, Mo, Rb, Sb, Sc, Se, Sm, Zn and W. In the injured tissue compared to the uninjured, calculation on a wet weight basis showed a decrease in Co, Cs, K, Mo, P, Rb and Zn, and an increase in Br, Ca, Ce, La, Na, Sb and Sm. The differences in Ca, La, Mo, P and Zn are dependent on the age of the myocardial infarction, and the regression lines for these elements are given. The concentration of the trace elements in uninjured tissue from infarcted hearts is compared to the ...

UK PubMed Central (United Kingdom)

We sought to determine the prevalence of metabolic syndrome (MS) in patients with acute myocardial infarction and its effect on clinical outcomes. Employing data from the Korea Acute Myocardial Infarction...Full Text Available

UK PubMed Central (United Kingdom)

The most frequent ultimate cause of death is myocardial arrest. In many cases this is due to myocardial hypoxia, generally arising from failure of the coronary macro- and microcirculation to deliver...Full Text Available

UK PubMed Central (United Kingdom)

Although peroxisome proliferator-activated receptor alpha (PPARα) is closely associated with myocardial fatty acid metabolism, the pathophysiological role of PPARα in myocardial infarction...Full Text Available

Science.gov (United States)

PMID:4447072

UK PubMed Central (United Kingdom)

Over 30 months 9292 consecutive patients admitted to nine coronary care units with suspected myocardial infarction were considered for admission to a randomised double blind study comparing the effect...Full Text Available

UK PubMed Central (United Kingdom)

ObjectiveTo investigate and to quantify the relationship between hospital costs and health outcomes for patients with acute myocardial infarction (AMI) in Veterans Health Administration...Full Text Available

UK PubMed Central (United Kingdom)

Health standards for truck drivers are higher than those for the general motoring public, particularly concerning the need to restrict driving following recovery from a myocardial infarction. An analysis...Full Text Available

UK PubMed Central (United Kingdom)

A 48-hour course of intravenous unfractionated heparin (UFH) is the standard of treatment in conjunction with fibrin-specific thrombolysis in ST-elevation myocardial infarction (STEMI). In recent trials,...Full Text Available

UK PubMed Central (United Kingdom)

The incidence of arrhythmias after acute myocardial infarction of the inferior wall varies with the affected segment and increases when there is right ventricular involvement. This paper provides a...Full Text Available

British Library Electronic Table of Contents (United Kingdom)

Ventricular septal defect after acute myocardial infarction (AMI) is a complication associated with poor outcome in the absence of intervention. We report a case of successful TEE guided transcatheter closure of a post myocardial infarction (MI) ventricular septal defect (VSD) with an Amplatzer occluder in a 79 years old male with cardiogenic shock.

British Library Electronic Table of Contents (United Kingdom)

Background: Mechanisms underlying the association between myocardial bridge (MB)-stenting and in-stent restenosis (ISR) are still unclear. Objective: To assess the impact of MB on ISR using intravascular ultrasound (IVUS). Methods: In the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial, 100 left anterior descending artery (LAD) culprit lesions (79 treated with paclitaxel-eluting stents [PES] and 21 treated with bare metal stents) were imaged with serial IVUS immediately postprocedure and at 13 months. Results: At baseline the LAD stent extended into the MB segment beyond the culprit lesion in seven patients (MB-stent group). In the remaining 93 patients the LAD stent was implanted only in the culprit lesion without extending into t...

UK PubMed Central (United Kingdom)

OBJECTIVES:To investigate the effect of opioid receptor blockade on the myocardial protection conferred by chronic exercise and to compare exercise training with different strategies...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Purpose: To report the detection of con-compacted ventricular myocardium (NVCM) with MRI compared to echocardiography in 8 patients. Material and methods: Non-compaction of the ventricular myocardium is a congenital disorder characterized by an altered structure of the myocardial wall resulting from an intrauterine arrest in endomyocardial embryogenesis. The morphological findings consist of a prominent meshwork of multiple myocardial trabeculations and deep intertrabecular recesses, communicating with the left ventricular cavity. 8 consecutive patients (mean age 7.3 years) with clinical and echocardiographic signs of NCVM were examined by MRI (1.5 T, Vision, Siemens) in short axis and 2- and 4-chamber views, using T{sub 1}-weighted TSE and Cine-GRE in 6 patients and true FISP sequences in 2 patients. MRI and echocardiography were evaluated for visibility, signs of NCVM and involvement of myocardial wall segments. Thickness ...

Energy Technology Data Exchange (ETDEWEB)

We determined the Na/K x-ray intensity ratio in frozen sections of myocardial tissues obtained at autopsy from patients who died from various causes, using electron probe analysis. We have been able to distinguish between the ischemically injured and normal cells. The method is simple, fast, and dependable even when the duration of ischemia is only 30 minutes.

Science.gov (United States)

Transcatheter coil embolization for coronary artery to left ventricular fistula was successfully performed in a neonate. At 30 weeks' gestation, fetal echocardiography showed a hypoplastic right ventricle with intact ventricular septum, absent pulmonary valve, tricuspid atresia, and marked distension of the right coronary artery. After birth, the neonate had congestive heart failure and the electrocardiogram showed myocardial ischemic changes in the left ventricular area. Aortography showed a dilated right coronary artery arising from the ascending aorta and draining into the left ventricle. Transcatheter coil embolization was carried out on the 9th day after birth. Since the procedure, no myocardial ischemic changes have been detected. Transcatheter coil embolization is a useful therapy for coronary artery fistula associated with myocardial ischemia. PMID:15564713

International Nuclear Information System (INIS)

Positron emission tomography (PET) is the gold standard for non-invasive assessment of myocardial viability and allows accurate detection of coronary artery disease by assessment of myocardial perfusion. Magnetic resonance imaging (MRI) provides high resolution anatomical images that allow accurate evaluation of ventricular structure and function together with detection of myocardial infarction. Potential hybrid PET/MR tomography may potentially facilitate the combination of information from these imaging modalities in cardiology. Furthermore, the combination of anatomical MRI images with the high sensitivity of PET for detecting molecular targets may extent the application of these modalities to the characterization of atherosclerotic plaques and to the evaluation of angiogenetic or stem cell therapies, for example. This article reviews studies using MRI and PET in parallel to compare their performance in cardiac ...

Energy Technology Data Exchange (ETDEWEB)

Twenty-four patients were studied with both /sup 201/Tl-thallus chloride and /sup 99m/Tc-TBI scintigraphy following exercise. Comparison of the two agents in detecting segmental myocardial ischemia and scar was made in 18 patients with evidence of coronary artery disease on /sup 201/Tl-thallous chloride scintigraphy. Agreement between the two studies was observed in 77% (125 of 162) of left ventricular segments, suggesting that /sup 99m/Tc-TBI can be used as a myocardial perfusion agent. Limitations were related to early high background activity from lungs and liver. The high lung activity and early myocardial redistribution within the 1st hour contributed to the failure of /sup 99m/Tc-TBI to detect 16 segmental defects seen in the immediate post-exercise thallous chloride scan. Persistently high liver activity additionally affected accurate interpretation in the left ventricular segments close to the diaphragm. Improvement ...

UK PubMed Central (United Kingdom)

Spontaneous coronary artery dissection (SCAD) is an extremely uncommon cause of myocardial infarction, occurring predominantly in women during or after pregnancy. The exact aetiology...Full Text Available

UK PubMed Central (United Kingdom)

The noninvasive assessment of cardiac function is of first importance for the diagnosis of cardiovascular diseases. Among all medical scanners only a few enables radiologists to evaluate the local cardiac...Full Text Available

UK PubMed Central (United Kingdom)

Background. Diabetes mellitus (DM) confers high vascular risk and is a growing national epidemic. We assessed clinical characteristics and prevalence of diagnosed DM among patients...Full Text Available

UK PubMed Central (United Kingdom)

Aneurysms of saphenous vein grafts are rare but can result in complications such as myocardial infarction or death. Percutaneous treatment has included a variety of approaches, including covered stents....Full Text Available

Science.gov (United States)

PMID:11835026

UK PubMed Central (United Kingdom)

Pericardial fat necrosis is an infrequent cause of acute chest pain and this can mimic acute myocardial infarction and acute pericarditis. We describe here a patient with the magnetic resonance imaging...Full Text Available

UK PubMed Central (United Kingdom)

A 57-year-old man with a history of coronary artery disease and placement of an implantable cardioverter-defibrillator presented at our emergency room with an anterior ST-elevation myocardial infarction....Full Text Available

UK PubMed Central (United Kingdom)

Objectives. Ninety-one fetuses with dilated or hypertrophic cardiomyopathy (DCM, HCM) and myocarditis were studied. Results. Group 1 “DCM”...Full Text Available

UK PubMed Central (United Kingdom)

The association of dietary glycaemic index (GI) and glycaemic load (GL) with cardiovascular diseases has been examined in several populations with varying results. We tested the hypothesis that...Full Text Available

UK PubMed Central (United Kingdom)

A mild stress such as brief ischemic episodes may protect the heart from a successive and more prolonged myocardial ischemia (ischemic preconditioning). This phenomenon is considered a typical “hormetic...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Myocardial time-activity curves can be described by two or more parameters. To establish the optimal curve fitting method 33 myocardial time-activity curves were analyzed with different curve fitting methods: monoexponential, biexponential and monoexponential plus constant. A background correction was not applied. Biexponential curve fitting resulted in redundancy of parameters. Optimal curve fitting was obtained with monoexponential plus constant. The constant represents the background activity together with the stores radiolabelled lipids and the half-time value represents the wash-out of radioiodide from the myocardium. A strong relation was found between the constant and the half-time value: small errors in the determination of the constant (background activity) resulted in considerable errors of the half-time value. It is concluded that optimal analysis of a myocardial time-activity curve can be performed with a ...

Energy Technology Data Exchange (ETDEWEB)

The atrial myocardium has been barely visible with thallium-201 myocardial scintigraphy. This is probably related to the difference in size, distance from anterior chest wall, and small coronary blood flow of the atrium, compared with the ventricle. We have encountered eight cases of visualization of the right atrial appendix (RAA). The RAA was identified from multiple projections in all cases and sometimes confirmed by radionuclide angiocardiography. Evidence derived from ECG, chest radiographs, and cardiac catheterization, indicated that the most important factor in the visualization might be the displacement of the RAA to a more anterior position.

British Library Electronic Table of Contents (United Kingdom)

A 60-year-old male was bitten by a venomous snake (Vipera ammodytes) and gradually developed signs of an allergic reaction including generalized itching, generalized rash, and chest discomfort. This was followed by severe retrosternal pain with electrocardiographic evidence of an inferior myocardial ischemia progressing to acute myocardial infarction. Cardiac enzymes and troponin, serum tryptase, and histamine were elevated. Coronary arteriography showed normal coronary arteries. This is a characteristic type I variant of Kounis syndrome, which is the concurrence of acute coronary syndromes with conditions associated with mast cell activation including allergic or hypersensitivity reactions as well as anaphylactic or anaphylactoid reactions. This is the first report to show that viper bite...

Energy Technology Data Exchange (ETDEWEB)

Despite extensive clinical use of thallium-201 (/sup 201/Tl) for myocardial imaging, the effect of ischemia on myocardial accumulation and release of /sup 201/Tl independent of flow has not been fully defined. Therefore, myocardial accumulation of /sup 201/Tl in response to ischemic-like myocardial injury was assessed in vitro using the cultured fetal mouse heart preparation. Cultured fetal mouse hearts (n . 311) were subjected to injury simulating ischemia by deprivation of oxygen and oxidizable substrates for periods ranging from 15 minutes to 10 hours. The extent of irreversible injury was determined by the percentage of lactic dehydrogenase (LDH) lost from the hearts to the culture medium during recovery from injury. Injury was essentially reversible at 1 hour of insult. The fraction of /sup 201/Tl content in injured compared with control hearts was not significantly lower after 1 hour of insult. By ...

International Nuclear Information System (INIS)

The diagnostic accuracy is compared of the dual-isotope protocol and the conventional "2"0"1Tl protocol, for detection of the coronary artery disease (CAD) using data on a total of 69 patients after myocardial infarction (MI). The "2"0"1Tl protocol was used to examine 44 patients, the dual-isotope protocol was used with 25 patients. All patients were examined by coronarography; a narrowing of the artery by more than 50 % was considered significant for CAD. The sensitivity, specificity and diagnostic accuracy was 97.7 %, 100 % and 97.7 % resp. for the "2"0"1Tl protocol, and 95.2 %, 75 % and 92 % resp. for the dual-isotope protocol. A higher diagnostic accuracy of the dual-isotope protocol has not been proven, and the "2"0"1Tl protocol continues to be used for examinations of patients after MI

Science.gov (United States)

The clinical manifestation of wounds of the heart is determined by the mode, site and size of the injury as well as the structure of the pericardial and myocardial lesion. Diagnosis can be confirmed by ECG and echocardiography. Only 20% of the patients with penetrating wounds of the heart live for more than 30 minutes. Pericardio-centesis should be used only to gain time for a safe sternotomy, cardiac decompression and suture of the wound of the heart. An aggressive surgical approach is mandatory. Cardiopulmonary bypass is necessary only to correct of concomitant lesions. PMID:1983618

Science.gov (United States)

We study the daily incidence of myocardial infarction deaths in Mexico for 4 years (1996-99) with a total of 129 917 cases in all the country, collected at the General Directorate of Epidemiology (National Ministry of Health). We divided the cases by sex and age and perform two kinds of analysis. First, we did an spectral analysis using the Maximum Entropy Method, considering the complete period, and minimum and maximum epochs of solar activity. The results show that the most persistent periodicity at higher frequencies in the myocardial infarction death occurrence is that of seven days. Considering the solar cycle phases, we found that during solar minimum times some frequencies are not detectable compared with solar maximum epochs, particularly that of seven days. Biological rhythms close to seven days, the circaseptans, are in general thought to be only the result of the social organization of life. However, this cannot be the only ...

Energy Technology Data Exchange (ETDEWEB)

We report a new case of Lyme disease with cardiac manifestations, which has been possible to follow during the long period of 12 years. We have detected the usual ECG abnormalities, and concentric hypertrophic myocardiopathy, by echocardiography. The acute myocarditis was demonstrated by /sup 111/In-antimyosin scintigraphy, which showed global myocardial uptake of the tracer, constituting the first report, to our knowledge, of Lyme myocarditis diagnosed by this method.

Energy Technology Data Exchange (ETDEWEB)

Purpose: Cardiomyopathy is one of the major complications of {beta} thalassaemia major as a result of transfusion iron overload. The aim of our study is to evaluate with MR if there is any difference of iron deposition signal intensity (SI) or distribution between non-cardiopatic and cardiopatic thalassaemic patients in order to establish if there is a relationship between cardiopathy and iron deposition. Materials and methods: We studied 20 patients affected by {beta} thalassaemia major, of whom 10 cardiopatic and 10 non-cardiopatic, and 10 healthy volunteers as control group. Serum ferritin and left ventricular ejection fraction were calculated in thalassaemic patients. All patients were examinated using a 1.5 MR unit with ECG-gated GE cine-MR T2*-weighted, SE T1-weighted and GE T2*-weighted sequences. In all cases, using an adequate ROI, the myocardial and skeletal muscle signal intensity (SI), the myocardial/skeletal ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study was to determine whether low doses of carbon monoxide (CO) exacerbate myocardial ischemia during a progressive exercise test. The effect of CO exposure was evaluated using the objective measure of time to development of electrocardiographic changes indicative of ischemia and the subjective measure of time to onset of angina. Sixty-three male subjects (41-75 years) with well-documented coronary artery disease, who had exertional angina pectoris and ischemic ST-segment changes in their electrocardiograms, were studied. Results from three randomized, double-blind test visits (room air, low and high CO) were compared. The effect of CO exposure was determined from the percent difference in the end points obtained on exercise tests performed before and after a 1-hr exposure to room air or CO. A significant dose-response relationship was found for the individual differences in the time to ST end point and angina for the pre-versus postexposure ...

International Nuclear Information System (INIS)

Cardiac disease research relies increasingly on small animal models and non-invasive imaging methods such as positron emission tomography (PET) and magnetic resonance imaging (MRI). Delayed enhancement magnetic resonance imaging (DE-MRI) using gadolinium-based contrast agents appear to be a visualizing infracted myocardium with high spatial resolution. Polar map (or bull's-eye image) was used to determination of the myocardial infarction area. Polar map is a comprehensive interpretation of the left ventricle. The infarct size was computed as the fraction of the total polar map areas. The threshold was computed as the percentage of mean intensity of the normal region. In other study, 50% predefined threshold value in varying range (30?70%) was most commonly use. However, predefined threshold value isn't acceptance in all case. The purpose of this study was to investigate methodological approach for automatic measurement of rat myocardial infarct ...

Science.gov (United States)

Four major natriuretic peptides have been isolated: atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and Dendroaspis-type natriuretic peptide (DNP). Natriuretic peptides play an important role in the regulation of cardiovascular homeostasis maintaining blood pressure and extracellular fluid volume. The classical endocrine effects of natriuretic peptides to modulate fluid and electrolyte balance and vascular smooth muscle tone are complemented by autocrine and paracrine actions that include regulation of coronary blood flow and, therefore, myocardial perfusion; modulation of proliferative responses during myocardial and vascular remodeling; and cytoprotective anti-ischemic effects. The actions of natriuretic peptides are mediated by the specific binding of these peptides to three cell surface receptors: type A natriuretic peptide receptor (NPR-A), type B natriuretic peptide receptor (NPR-B), ...

British Library Electronic Table of Contents (United Kingdom)

Hsp20, referred to as HspB6, is constitutively expressed in various tissues. Specifically, HspB6 is most highly expressed in different types of muscle including vascular, airway, colonic, bladder, and uterine smooth muscle; cardiac muscle; and skeletal muscle. It can be phosphorylated at Ser-16 by both cAMP- and cGMP-dependent protein kinases (PKA/PKG). Recently, Hsp20 and its phosphorylation have been implicated in multiple physiological and pathophysiological processes including smooth muscle relaxation, platelet aggregation, exercise training, myocardial infarction, atherosclerosis, insulin resistance and Alzheimer's disease. In the heart, key advances have been made in elucidating the significance of Hsp20 in contractile function and cardioprotection over the last decade. This mini-rev...

British Library Electronic Table of Contents (United Kingdom)

BACKGROUND AND PURPOSE It is well established that cytochrome P450 2J (CYP2J) enzymes are expressed preferentially in the heart, and that ebastine is a substrate for CYP2J, but it is not known whether ebastine is metabolized in myocardium. Therefore, we investigated its pharmacokinetics in the rat isolated perfused heart. EXPERIMENTAL APPROACH Rat isolated hearts were perfused in the recirculating mode with ebastine for 130-min. The concentrations of ebastine and its metabolites, hydroxyebastine and carebastine, were measured using liquid chromatography with a tandem mass spectrometry. The data were analysed by a compartmental model. The time course of negative inotropic response was linked to ebastine concentration to determine the concentration-effect relationship. KEY RESULTS Ebastine w...

British Library Electronic Table of Contents (United Kingdom)

It is uncertain if downregulation of ?-adrenoceptor signaling pathway is promoted by an enhanced adrenergic tone at an early stage of cardiac disease, or it develops secondary to detrimental local myocardial changes in advanced heart failure. We examined the integrity of ?-adrenoceptor signaling pathway upon chronic infusion of isoproterenol, a ?-adrenoceptor agonist, at a dose producing no structural left ventricular (LV) remodeling and systolic dysfunction. Subcutaneous isoproterenol infusion (400??g?kg?1?h?1 over 16?days) to guinea pigs using osmotic minipumps produced no change in cardiac weights, LV internal dimensions, myocyte cross-sectional area, extent of interstitial fibrosis, and basal contractile function. Isolated, perfused heart preparations from isoproterenol-treated guinea ...

British Library Electronic Table of Contents (United Kingdom)

AbstractBackground Few published data are available on the benefits of aspirin use in patients with unstable angina (UA). Hypothesis Aspirin use carries a mortality benefit in a population-based cohort of patients presenting with UA. Methods All residents of Olmsted County, Minnesota presenting to local emergency departments with acute chest pain from January 1985 through December 1992 having symptoms consistent with UA were identified through medical records. A total of 1628 patients were identified with UA and were stratified by aspirin use in-hospital and at discharge. Cardiovascular mortality and nonfatal myocardial infarction and stroke were assessed over a median of 7.5 years follow-up and all-cause mortality data over a median of 16.7 years. The mean age of patients with UA was 65 y...

British Library Electronic Table of Contents (United Kingdom)

All patients with von Willebrand?s disease (vWD) who showed an arterial or venous thrombosis and were reported in the literature have been evaluated. 11 patients had arterial thrombosis while 19 had venous thrombosis for a total of 30 cases. 9 out the 11 cases with arterial thrombosis had myocardial infarction. Two had cerebral thrombosis. Associated risk factors for arterial thrombosis were available only for three patients who showed, respectively, smoking and dyslipidemia (2 cases) and smoking and intravenous desmopressin infusion (1 case). The majority of patients with venous thrombosis showed DVT with or without PE. Four patients presented with apparently isolated PE. In two instances thrombosis occurred in unusual sites (central retinal vein and portal vein, respectively). Several as...

Energy Technology Data Exchange (ETDEWEB)

The Subcommittee for Surveillance of Nuclear Medicine Practice has implemented a survey for actual nuclear medicine practice in Japan every 5 years. This article reports on the third survey implemented during a one-month period in June 1992. Questionnaires were sent to all 1256 facilities employing radiopharmaceuticals in routine practice, and 1162 (92.5%) answered. In vivo nuclear medicine examinations per day were performed in 6600 cases. SPECT accounted for 19.4%, as compared with 7.1% in the 1987 survey. According to organs, the frequency of examination for the cerebrospinal region was 3.2 and 2.2 times higher than that in the 1982 and 1987 surveys, respectively, whereas for the thyroid gland it was 0.6-fold and 0.7-fold that of these surveys. The proportion of bone scintigraphy was the highest (24.5%), followed by tumor scintigraphy (14.1%) and myocardial scintigraphy (11.9%). The frequency of myocardial and cerebral blood flow ...

Science.gov (United States)

The effect of exercise training prior to acute myocardial infarction (AMI) on left ventricular (LV) remodeling is poorly understood. This study investigated the protective effect of 3 weeks of swimming exercise training prior to AMI on cardiac morphology and function. Male Sprague-Dawley rats (n = 35) were randomly assigned to 3 groups: swimming training (n = 14, 90 min, 5 days/wk, 3 wk), sedentary (n =14), and controls (n = 7, no exercise, no MI). At the end of the training/sedentary period, rats were subjected to AMI (ExMI and SedMI) induced by surgical ligation of the left coronary artery. Thereafter, the rats remained sedentary for a 4-wk recovery period. Trans-thoracic echocardiography was performed in each group at the end of the exercise/sedentary period (pre-AMI), 24 hr after AMI, and following recovery (4 wk after AMI). No differences were observed in LV dimensions and function pre-AMI among the 3 groups; however, LV-end systolic diameter (LVESD) and ...

International Nuclear Information System (INIS)

Introduction: Previous studies have published the correlation between myocardial perfusion SPECT (MP) during cold pressor test (CPT) and intracoronary acetylcholine and its usefulness as independent marker of endothelial dysfunction (ED). Objective: To analyze the incidence of positivization of MP exercise studies in the follow up of asymptomatic patients with moderate cardiovascular risk (CV) and ED detected by PF. Material and Methods: Of 301 patients of the PARADIGMA Registry (normal exercise MP SPECT and clinical probability < 20% of events at 10 years [moderate risk by Framingham index]) 55 had positive PF (+) (18.3%). Prospectively and consecutively, 15 asymptomatic patients with PF (+), and a control group (CG) of 15 patients with negative PF, with paired sex, age and coronary risk factors (CRF), that accomplished a 12 #+-# 2 months follow up, and that underwent a new exercise and resting MP SPECT were analyzed. An MP extension score was used in a model ...

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Abstract not provided

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

The work examines twenty-two patients with coronary artery disease, previous myocardial infarction and LV dysfunction, using the technetium-99m ({sup 99m}Tc) tetrofosmin (SPECT) associated with nitrate administration in the detection of hypoperfused but still viable myocardium. The method allows the detection of this disease. [Italian] Il lavoro analizza i risultati degli esami condotti su 22 pazienti con cardiopatia ischemica cronica e ridotta funzione ventricolare sinistra sottoposti a tomografia computerizzata con emissione di fotone singolo (SPECT) cardiaca con tecnezio-99m ({sup 99m}Tc) tetrofosmina associata alla somministrazione di nitrati nella differenziazione tra tessuto miocardico ipoperfuso ma ancora vitale e tessuto miocardico necrotico. La metodologia usata consente di identificare la presenza di tessuto miocardico vitale in territori vascolari severamente ipoperfusi.

British Library Electronic Table of Contents (United Kingdom)

Background: The outcome of acute myocardial infarction (AMI) complicated with cardiogenic shock is poor. The aim of this study was to analyse, whether upfront abciximab administration could improve the outcomes of cardiogenic shock. Methods: This multicentre open trial randomized 80 patients with AMI complicated by cardiogenic shock expected to undergo primary PCI into group A (routine upfront-pre-procedural-abciximab bolus followed by 12-h abciximab infusion) and group B (standard therapy). The study primary objective was 30-day combined outcome (death/reinfarction/stroke/new severe renal failure). Results: PCI was technically successful in 90% (A) versus 87.5% (B) patients. Abciximab was used in 100% (A) versus 35% (B). The primary endpoint occurred in 17 group A patients (42.5%) and 11 ...

Energy Technology Data Exchange (ETDEWEB)

A new /sup 99m/Tc-phosphine-isocyanide complex with the general structure (/sup 99m/Tc (DEPE)/sub 2/(CNR)/sub 2/)/sup +/ has been synthesised and tested in animals and one human. In three animal species (rat, rabbit, dog), the complex is an efficient myocardial imaging agent, while in humans it remains in the blood pool. The complex is 100% protein bound in animals and humans, but whereas in humans it is attached to a 51.5 kdalton protein (probably prealbumin), in rabbits it appears to be bound to a larger macromolecule (M.W.>100 kdalton). The efficiency of the complex for blood pool labelling was tested in a human volunteer and compared with the standard in vivo red cell labelling technique with stannous pyrophosphate. A satisfactory radionuclide angiogram could be performed with less than 370 MBq of the complex. The count rate for the complex (cps/MBq) was 15% higher than that obtained with the labelled red cells and the absence of splenic activity was ...

Energy Technology Data Exchange (ETDEWEB)

Independent calculations of the antiproton-to-proton ratio by Gaisser and Maurer and by Badhwar et al. have produced conflicting results which obscure the interpretation of recent measurements of cosmic ray antiprotons. A detailed reexamination of these calculations has been performed and these differences have been resolved. We find that the first calculation was essentially correct and the reported fluxes of antiprotons are significantly higher than expected for secondary antiprotons in conventional models of cosmic ray propagation, as indicated by other recent calculations.

Energy Technology Data Exchange (ETDEWEB)

Perturbative approach to two-dimensional gravity and supergravity is considered. One-loop renormalization of the central charge of SL(2,R) Kac-Moody algebra is calculated perturbatively by functional integration and by explicit calculations of the Feynman diagrams. Also the wavefunction renormalization and the anomalous dimensions in the presence of gravity are calculated.

International Nuclear Information System (INIS)

Calculations, drawing principally on developments at AERE Harwell, of the relaxation about lattice defects are reviewed with emphasis on the techniques required for such calculations. The principles of defect modelling are outlined and various programs developed for defect simulations are discussed. Particular calculations for metals, ionic crystals and oxides, are considered. (UK).

International Nuclear Information System (INIS)

This handbook breaks down the complex field of nuclear reactor calculations into major steps. Each step presents a detailed analysis of the problems to be solved, the parameters involved, and the elaborate computer programs developed to perform the calculations. This book bridges the gap between nuclear reactor theory and the implementation of that theory, including the problems to be encountered and the level of confidence that should be given to the methods described. Volume III: Control Rods and Burnable Absorber Calculations. Perturbation Theory for Nuclear Reactor Analysis. Thermal Reactors Calculations. Fast Reactor Calculations. Seed-Blanket Reactors. Index.

Energy Technology Data Exchange (ETDEWEB)

Radiation Damage Calculations for the FUBR and BEATRIX Irradiations of Lithium Compunds in EBR-II and FFTF

Energy Technology Data Exchange (ETDEWEB)

A simple heuristic calculation is given for the rate of nucleation of black holes at positive temperature. This calculation is based on the classical theory of nucleation and reproduces the result of Gross, Perry, and Yaffe.

International Nuclear Information System (INIS)

The detection efficiency of a lithium glass detector was calculated using MCNP code, and the calculation was compared with the published results in Pulsed Sphere Plan. A lithium glass detector of our own was made, and its neutron efficiency was calculated. The calculated neutron efficiency was verified with both pulsed and steady DD neutrons. Characteristics of Neutron response of "6Li detector was discussed. (authors)

Energy Technology Data Exchange (ETDEWEB)

Short communication.

International Nuclear Information System (INIS)

To calculate the energy band structures in semiconductors using the relativistic augmented plane wave method, atomic potential and charge density are needed, which are calculated by self-consistent method. Wave function for one electron is determined by solving the Dirac equation with the Hartree-Fock equation based on the slater's exchange potential. The results of calculation for Cu"+"1 are given. (Author).

KoreaScience (Korea)

Full Text Available

International Nuclear Information System (INIS)

On the basis of symmetry way of texture description a calculation method of elastic moduli of two-phase titanium alloys with rolling texture has been suggested. Efficiency of the calculation formulas is checked by comparing the calculation results of Young modulus anisotropy in the sheet plane of (#alpha#+#beta#)-titanium alloy VT23 with the experimental data.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This paper presents fundamental researches based on the electronic structure calculations and X absorption spectroscopy, allowing the knowledge on nuclear fuels at an atomic scale. They bring a better understanding of these material behavior to accurate the macroscopic simulation. The calculation methods, the experimental techniques of validation and the ab initio calculations results are detailed. (A.L.B.)

International Nuclear Information System (INIS)

By the linear augmented plane wave method (APW) the energy zone of silver and technetium structure is calculated. The potential has been determined by means of superposition of atomic charge densities according to slater exchange method. Total and partial state densities have been calculated by the tetrahedron method. The APW-method convergence on the example of silver is studied, the comparison with the calculation results by the APW method and other data is carried out. The APW method high efficiency is pointed out. In dipole approximation the intensity distribution in L"3, M"5 N"3 technetium emission spectra is calculated.

International Nuclear Information System (INIS)

Metabolic profile is an important biological marker of neoplastic processes not only in the tumor itself but also in the host organism. The neuro-hormone melatonin has been implicated in the experiments as an oncostatic agent. Female Wistar:Han SPF rats (Velaz, Prague, Czech Republic) were irradiated continuously for 15 days using a daily gamma rays dose of 96 mGy. At the end of exposure one group of rats was administered 5 mg/kg b.w. of dimethylbenz/a/anthracene (DMBA) intragastrically. During the period of exposure to ionizing radiation a part of the animals was supplied with melatonin (M) at a concentration of 20 #mu#l/ml in drinking water. Selected parameters of lipid and carbohydrate metabolism and levels of selected hormones were determined 2, 30 and 100 days post-irradiation. The irradiation itself caused only small changes in tissue lipids. The application of a single low dose (subthreshold from the point of view of induction of mammary tumors) of DMBA caused more pronounced ...

International Nuclear Information System (INIS)

Purpose: To quantify left ventricular function derived from retrospectively ECG-gated multislice spiral CT (MSCT) data sets in comparison to MRI. Materials and Methods: In 16 patients (14 males, 2 females, mean age 56.8 #+-# 11.5 years), retrospectively ECG-gated MSCT angiography of the coronary arteries and breath-hold steady state free precession cine MRI were performed. From MSCT data-sets, 20 axial image series were reconstructed every 5% of the RR interval. Multiplanar images were reformatted in the short axis orientation from axial images. End-systolic and end-diastolic images were selected. From these images end-systolic volume (ESV), end-diastolic volume (EDV) and stroke volume (SV) as well as the ejection fraction (EF) and myocardial mass (MM) were determined using the Simpson's method and compared with MRI. Furthermore, image quality was assessed for both imaging modalities using a four point grading scale. Results: All parameters were found to have an ...

Energy Technology Data Exchange (ETDEWEB)

Positron Emission Tomography (PET) was used to analyze in vivo antagonist binding to human myocardial muscarinic cholinergic receptor. The methiodide salt of the muscarinic antagonist, quinuclidinyl benzilate (MQNB), was labeled with the positron emitter, Carbon-11, and injected intravenously to 8 normal subjects. /sup 11/C-MQNB concentration was determined in vivo in the ventricular septum from 40 cross-sectional images acquired at the same transverse level over a period of 70 minutes. In 4 subjects, various amounts of unlabeled atropine were rapidly injected at 20 minutes to study whether atropine competitively inhibited MQNB. The kinetics of binding of /sup 11/C-MQNB were not the same in vivo and in vitro. The apparent dissociation rate of /sup 11/C-MQNB in vivo was much slower (by 1 to 2 orders of magnitude) than that observed in vitro with /sup 3/H-QNB. After atropine injection, /sup 11/C-MQNB dissociated from its binding sites at a rate that apparently ...

Science.gov (United States)

Cardiac contractile function is dependent on the integrity and function of the sarcolemmal membrane. Swimming exercise training is known to increase cardiac contractile performance. The purpose of the present study was to examine whether a swimming exercise program would alter sarcolemmal enzyme activity, ion flux, and composition in rat hearts. After approximately 11 wk of exercise training, cardiac myosin and actomyosin Ca2+-adenosinetriphosphatase (ATPase) activity was significantly higher in exercised rat hearts than in sedentary control rat hearts. Glycogen content was increased in plantaris and gastrocnemius muscles from exercised animals as was succinic dehydrogenase activity in gastrocnemius muscle of exercised rats in comparison to sedentary rat preparations. Sarcolemmal vesicles were isolated from hearts of exercise-trained and control rats. Sarcolemmal Na+-K+-ATPase and K+-p-nitrophenylphosphatase activities, Na+-Ca2+ exchange, and passive Ca2+ binding did not differ between ...

International Nuclear Information System (INIS)

A burgeoning interest in technetium coordination chemistry has been spurred by its widespread use in nuclear medicine. Recent focus has been on the design and preparation of new technetium complexes, the lipophilicity, polarity, and overall charge of which can be readily altered by simple substitutions in the molecular framework of the ligand in order to optimize the biodistribution and target specific organs. Examples are cationic (Cardiolite) and neutral (Ceretec) technetium complexes, used as myocardial and brain imaging agents, respectively. The authors have been pursuing a continuing study of tris(3-hydroxy-4-pyridinonato)gallium and -indium complexes that are water soluble, are hydrolytically stable, and are of varying lipophilicity and neutral charge. Studies of in vivo in rabbits and mice have revealed that several of these cationic complexes may be useful as morphologic kidney imaging agents, with ["9"9"mTc(pap)_3]"+ showing elevated levels in the kidneys ...

Energy Technology Data Exchange (ETDEWEB)

The implicit curve-fitting method has been used for fast and stable calculations of thermodynamic properties of subcritical refrigerants, and it has to use the saturated liquid or vapor state as the reference state. In order to extend the application range of this method in supercritical region, an isothermal state in the supercritical region is used as the reference state, and the implicit equations for supercritical refrigerants in this state and out of this state are established, respectively. The new calculation method can be used in the entire supercritical region. With the new method, thermodynamic properties of supercritical CO{sub 2} and R410A are predicted and compared with REFPROP 8. It shows that the total mean relative deviations of the fast calculation formulae from REFPROP 8 are less than 1%, while the mean calculation speeds of the fast calculation formulae are more ...

Energy Technology Data Exchange (ETDEWEB)

Much attention is being paid to electric vehicles from environmental standpoints. One disadvantage of the electric vehicle is that its operative range is short. A means to overcome this difficulty is to use a hybrid battery which consist of a energy battery and a power battery. A method to make it possible to calculate the discharge characteristics of the battery hybrid system taking into account the charging behavior from the energy battery to the power battery is presented. In the proposed method, first the output voltage and the output current of an equivalent battery, which is required for realizing the given operating pattern are calculated. Next, the conduction ratio of the main chopper and the equivalent discharge of electric charge of each battery are calculated. These calculated data are used to calculate the operating range.

UK PubMed Central (United Kingdom)

The rate of appearance of unlabelled glucose was calculated from tracer data and compared with the actual rate of infusion of unlabelled glucose into a anaesthetized dog with all sources of endogenous...Full Text Available

UK PubMed Central (United Kingdom)

Calculations of dose per monitor unit (D∕MU) are required in addition to measurements to increase patient safety in the clinical practice of proton radiotherapy. As in conventional photon and...Full Text Available

UK PubMed Central (United Kingdom)

Numerical calculations of static, switched, and radiofrequency (RF) electromagnetic (EM) fields considering the geometry and EM properties of the human body are used increasingly in MRI to explain...Full Text Available

Science.gov (United States)

Examples are used to demonstrate that a shift in the point of emphasis is necessary with regard to radiation hazard in medicinal X-ray diagnosis. The parameters employed in this study to calculate somatic dose (SD) and somatically significant dose (SSD) m...

Energy Technology Data Exchange (ETDEWEB)

Calculations of refrigerant thermal properties are desired to be very fast and stable in cases of simulation of refrigeration system, etc. The traditional method based on equation of state cannot meet such requirement because of unavoidable iterations in calculation. In this paper, a new calculation method for refrigerant thermal properties is presented. Low order implicit polynomial equations are got by using curve-fitting method at first, and then explicit formulae for calculating refrigerant thermal properties quickly are obtained by getting the analytical solution of these implicit equations. Explicit fast calculation formulae for thermal properties of R22 and R407C, covering the saturated temperature of -60{approx}80 {sup o}C and superheat of 0-65 {sup o}C, are presented as examples. The calculation speeds of the formulae of R22 are about 140 times faster ...

UK PubMed Central (United Kingdom)

ObjectiveCompare occlusal contacts calculated from 3D virtual models created from clinical records to contacts identified clinically using shimstock and transillumination.Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The wave function of the Bianchi type-IX universe with small anisotropy is calculated using the Hartle-Hawking prescription.

Energy Technology Data Exchange (ETDEWEB)

The effects of various approximations used in performing augmented-plane-wave calculations were studied for elements of the fifth and sixth columns of the Periodic Table, namely V, Nb, Ta, Cr, Mo, and W. Two kinds of approximations have been checked: (i) variation of the number of k points used to iterate to self-consistency, and (ii) approximations for the treatment of the core states. In addition a comparison between relativistic and nonrelativistic calculations is made, and an approximate method of calculating the spin-orbit splitting is given.

Energy Technology Data Exchange (ETDEWEB)

Different calculated models are presented for turbulent break-off flows and their classification, reflecting the sequence of historical development. The study was done based on equations of viscous liquid of the Navier-Stokes type with development of special phenomenological models of turbulence which take into consideration real properties of the break-off flows based on simpler models of flow presented in the work. In order to calculate two-dimensional turbulent flows, a method of viscous-nonviscous interaction is used. It employs numerical solutions for nonviscous flow and integrated methods of calculating the dissipative region. This method can be extended for calculating the transonic break-off flows, and also break-off in an incompressible fluid when there is cavitation.

Science.gov (United States)

... elements of the parameter covariance matrix computed from the partial derivative matrix and Vpqrs(',I). We also calculate ...

Science.gov (United States)

The results of a study conducted by Working Group 10 of the AGARD Fluid Dynamics Panel to investigate the limits of boundary layer methods, both the integral and field type formulations, for calculating three-dimensional turbulent separated flow are presented. Test cases used to assess the boundary layer calculations included the DFLVR prolate spheroid at angle of attack and the NASA-Ames Wing C. Comparisons between boundary layer calculations and experimental data are presented for these test cases along with observations, conclusions, and recommendations.

International Nuclear Information System (INIS)

... computer calculations fftf reactor nonlinear problems reactor accidents reactor

International Nuclear Information System (INIS)

... angular momentum cranking model even-even nuclei gadolinium 156 governor

Energy Technology Data Exchange (ETDEWEB)

MINEQL is a subroutine package to calculate equilibrium composition of an aqueous system, accounting for mass transfer.

Science.gov (United States)

... The ultimate compressive strength was measured, and values for Young's modulus were calculated from the linear portion of the test curve. ...

Energy Technology Data Exchange (ETDEWEB)

We provide two examples to illustrate how electronic structure calculations contribute to our understanding of vacancies and their role in determining material properties. Diffusion and elctromigration in aluminium are known to depend strongly on vacancies. Electronic structure calculations show that the vacancy-impurity interaction oscillates with distance, and this leads to an explanation for both the increased elctromigration resistance and the slow impurity diffusion for copper in aluminium. Calculations of vacancies in plutonium have been used in conjunction with positron annihilation lifetime measurements to identify the presence of helium-filled vacanies. Helium stabilization of vacancies can provide the precursors for subsequent vacancy-related changes in materials properties.

Energy Technology Data Exchange (ETDEWEB)

The linear integral equation based computer code (RON: Roger Oleg Nikolai), which was recently developed at Argonne National Laboratory, was used to calculate the self-amplified spontaneous emission (SASE) performance of the free-electron laser (FEL) being built at Argonne. Signal growth calculations under different conditions are used for estimating tolerances of actual design parameters. The radiation characteristics are discussed, and calculations using an ideal undulator magnetic field and a real measured magnetic field will be compared and discussed.

International Nuclear Information System (INIS)

This handbook breaks down the complex field of nuclear reactor calculations into major steps. Each step presents a detailed analysis of the problems to be solved, the parameters involved, and the elaborate computer programs developed to perform the calculations. This book bridges the gap between nuclear reactor theory and the implementation of that theory, including the problems to be encountered and the level of confidence that should be given to the methods described. Volume II: Monte Carlo Calculations for Nuclear Reactors. In-Core Management of Four Reactor Types. In-Core Management in CANDU-PHW Reactors. Reactor Dynamics. The Theory of Neutron Leakage in Reactor Lattices. Index.

Energy Technology Data Exchange (ETDEWEB)

Monte Carlo methods have been used to compute k{sub eff} and the fundamental mode eigenfunction of critical systems since the 1950s. While such calculations have become routine using standard codes such as MCNP and SCALE/KENO, there still remain 3 concerns that must be addressed to perform calculations correctly: convergence of k{sub eff} and the fission distribution, bias in k{sub eff} and tally results, and bias in statistics on tally results. This paper provides a review of the fundamental problems inherent in Monte Carlo criticality calculations. To provide guidance to practitioners, suggested best practices for avoiding these problems are discussed and illustrated by examples.

Energy Technology Data Exchange (ETDEWEB)

The results of an investigation of the effects of several parameters on the reactivity instability of a Boiling Water Reactor (BWR) calculational model are summarized. Calculations were performed for a typical BWR operated at low flow conditions, where reactivity instabilities are more likely to occur. The parameters investigated include the axial power shape (characterized by two separate parameters), the core pressure, and operating flow. All calculations were performed using the LAPUR code which was developed at the Oak Ridge National Laboratory for the dynamic modeling of large BWR's. 4 refs., 8 figs.

Energy Technology Data Exchange (ETDEWEB)

Equations are derived to permit calculation of the work required for the isentropic compression of a two phase fuel-air mixture. Methanol evaporation during compression is shown to substantially reduce compression work and thereby improve cycle efficiency and maximum power. Effects of evaporative cooling in the intake manifold are calculated. 14 refs.

International Nuclear Information System (INIS)

The approach estimating the leak probability of flanged joint due to the destruction of fastening studs is described. The mentioned approach consists of two stages. The probability of destroying one stud is calculated at the first stage, and the probability of different combination interpositions of intact and destroyed studs is calculated at the second one. The probability calculation of leak in the area of collector cover of steam generator PGV-1000 is used as an example of developed approach

International Nuclear Information System (INIS)

A cell calculation code SLAROM-UF was developed to improve calculation accuracy of effective cross sections for various fast reactor types. SLAROM-UF has a capability to calculate effective cross sections in ultra fine groups of about 100,000 below 50keV and in fine groups above the energy (maximum 900 groups). Resonance interaction among the fuel, the coolant, and the structure materials can be treated accurately even in a heterogeneous cell structure. Temperature can be set up freely in a cell by the ultra fine group calculation. Improvement in nuclear characteristics was observed in the analysis of JUPITER critical experiment, as 0.1% for criticality, 4% for sodium void reactivity, several % for radial reaction rate distribution, when SLAROM-UF was used instead of the typical cell calculation code. The effect of the ultra fine group calculation is remarkable ...

International Nuclear Information System (INIS)

Monte Carlo calculations performed to validate observed capture reaction rates of "1"2"9I and "2"3"7Np were in a reasonable agreement with experimental data obtained by the Joint Institute for Nuclear Research. The most significant discrepancy between the measurements and calculations (within a factor of 3) was observed for the NpO_2 sample and Pb target at 3.7 GeV proton energy

Energy Technology Data Exchange (ETDEWEB)

The calculations with the broad-group cross-section library Bugle-96, and atom displacement (dpa) cross sections for iron, both derived from ENDF/B-VI data, result in higher calculated fast neutron fluxes, better agreement of calculations with radiometric dosimeter measurements, and significantly slower dpa rate attenuation through pressure vessel walls relative to the results with their predecessors: the Sailor library and ASTM iron dpa cross sections.

International Nuclear Information System (INIS)

Li shell-model calculation has been made in the isospin formalism in the complete (0 + n)#Planck constant##omega# model space with the assumption of a closed core "4He. The calculation could probably be improved by use of a better effective interaction and increasing shell model space. With the use of faster computer with large memories, the authors are in hope of calculation in spsd shell-model space

International Nuclear Information System (INIS)

Cross sections for elastic scattering of 12 GeV protons from "4"0Ca nuclei have been calculated using the flucton model. The influence of the collective flucton nucleon correlations on the calculated cross sections is examined. The calculated cross sections are in significant disagreement with the experimental data. This may be considered as an argument against the flucton model. (orig.).

International Nuclear Information System (INIS)

A possibility of short-lived isotopes production in inter-tank section between the first and the second drift tube tanks (20.45 MeV) in INR linac is considered. At the initial stage the main efforts are concentrated on production of fluorine-18 used for positron emission tomography. The results of beam forming calculations, target heating calculations, equipment activation calculations as well as installation configuration and design are presented.

International Nuclear Information System (INIS)

Calculations of the Compton profiles for the transition metals Ta and W are performed, using electron wave functions obtained from self-consistent augmented plane wave (APW) band structure calculations within the local density formalism of Hedin-Lundqvist. Relativistic effects are included except for the spin-orbit interaction. The observed structures of the Compton profiles in these metals are understood in terms of the topology of their Fermi surfaces. (author).

Science.gov (United States)

A numerical method for the calculation of unsteady, inviscid turbomachine flow in the transonic velocity range is described. The calculation of complete stages is possible. If the flow layer geometry is given, the flow field can be determined by independe...

Energy Technology Data Exchange (ETDEWEB)

This program is designed in order to calculate electricity generation cost by different energy sources, and menu type is adopted for user convenience. This program also graphically shows the share of capital investment cost, O and M cost, and fuel cost. Sensitivity analysis about discount rate can also be carried out by this program, taking into consideration the important role of the discount rate in the generation costs calculation. (Author) 7 refs., 1 fig., 3 tabs.

International Nuclear Information System (INIS)

The implementation of the convolution/superposition method in real dose planning situations is considered. The modelling of photon spectra, the use of patient and treatment setup information, and the calculation of the photon energy released in a patient are detailed. A comparison is made between the approaches of calculating the relative dose directly and using a factor derived from measurements to correct the calculated relative dose. 13 refs.; 7 figs.

Science.gov (United States)

We describe calculations of the energy loss, range, stopping power, multiple scattering, and other related properties of a high-energy heavy-ion beam at any one of a set of beam line elements. A beam line element (e.g., any beam modification, detection, or control device) is characterized by its thickness, areal density, aperture, and function. The loss of multiply scattered particles to any finite-aperture detector is calculated in the small-angle approximation, and the position of the Bragg peak, as given by particles stopping in the second of two ionization chambers used for Bragg curve measurements, is estimated. A general purpose computer program, PROPAGATE, has been written to allow addition, deletion, and modification of the beam line elements used in the calculation and to provide a convenient means of repeating such calculations for arbitrary beam lines. Calculations and ...

Energy Technology Data Exchange (ETDEWEB)

Code coupling activities have so far focused on coupling the neutronics modules with the CFD module. An interface module for the CFD-ACE/DeCART coupling was established as an alternative to the original STAR-CD/DeCART interface. The interface module for DeCART/CFD-ACE was validated by single-pin model. The optimized CFD mesh was decided through the calculation of multi-pin model. It was important to consider turbulent mixing of subchannels for calculation of fuel temperature. For the parallel calculation, the optimized decompose process was necessary to reduce the calculation costs and setting of the iteration and convergence criterion for each code was important, too.

International Nuclear Information System (INIS)

Electromagnetic forming (EMF) is a forming process that relies on the inductive electromagnetic force to deform metallic workpiece at high speed. Calculation of the electromagnetic force is essential to understand the EMF process. However, accurate calculation requires complex numerical solution, in which the coupling between the electromagnetic process and the deformation of workpiece needs be considered. In this paper, an appropriate formula has been developed to calculate the electromagnetic force in metal work-piece in the sheet EMF process. The effects of the geometric size of coil, the material properties, and the parameters of discharge circuit on electromagnetic force are taken into consideration. Through the formula, the electromagnetic force at different time and in different positions of the workpiece can be predicted. The calculated electromagnetic force and magnetic field are in good ...

Energy Technology Data Exchange (ETDEWEB)

An important component of the overall program to validate WIMS-AECL for use with RFSP in the analysis of CANDU-6 reactors for design and safety analysis calculations is the validation of calculations of incremental cross sections used to represent reactivity devices. A method has been developed for the calculation of the three-dimensional neutron flux distribution in and around CANDU reactor fuel channels and reactivity control devices. The methods is based on one- and two dimensional transport calculations with the WIMS-AECL lattice cell code, SPH homogenization, and three-dimensional flux calculations with finite-difference diffusion theory using the MULTICELL code. Simulations of Wolsung 1 Phase-B commissioning measurements and Point Lepreau restart tests have been performed, as a part of the program to validate WIMS-AECL lattice cell calculations for ...

International Nuclear Information System (INIS)

Neutron and gamma ray energy spectra were measured using an NE-213 scintillator at depths of 7.2, 15.2, and 22.2 cm in a tissue-equivalent phantom which was uniformly irradiated on one face by deuterium--tritium (DT) neutrons. Coupled neutron--gamma ray multigroup discrete-ordinates calculations were performed using semi-infinite slab geometry. These calculations were used to supplement the measured spectra below 1 MeV. Similar calculations were performed to study the perturbation in the phantom due to the detector. The measured and calculated spectra were used to determine the kerma distributions for neutrons and gamma rays at each location. The gamma radiation was determined to contribute more than 10% of the total dose at each depth. The calculated kerma also reveals that a knowledge of the gamma ray spectra below 1 MeV is desirable. Key words: neutron--gamma spectra, ...

International Nuclear Information System (INIS)

IMRT optimization requires a fast yet relatively accurate algorithm to calculate the iteration dose with small memory demand. In this paper, we present a dose calculation algorithm that approaches these goals. By decomposing the infinitesimal pencil beam (IPB) kernel into the central axis (CAX) component and lateral spread function (LSF) and taking the beam's eye view (BEV), we established a non-voxel and non-beamlet-based dose calculation formula. Both LSF and CAX are determined by a commissioning procedure using the collapsed-cone convolution/superposition (CCCS) method as the standard dose engine. The proposed dose calculation involves a 2D convolution of a fluence map with LSF followed by ray tracing based on the CAX lookup table with radiological distance and divergence correction, resulting in complexity of O(N"3) both spatially and temporally. This simple algorithm is orders of magnitude faster ...

International Nuclear Information System (INIS)

We calculated the energies of asymmetric nuclear matter at zero and finite temperatures with the cluster variational method. At zero temperature, the expectation value of the two-body Hamiltonian composed of the kinetic energies and the AV18 two-body forces is calculated with the Jastrow wave function in the two-body cluster approximation. The obtained two-body energy is in good agreement with the result with the Fermi Hypernetted Chain (FHNC) calculation by Akmal et al. The energy caused by the UIX three-body forces is treated somewhat phenomenologically so that the total energy reproduces the empirical saturation point. Furthermore, the parameters included in the three-body energy are readjusted so that the Thomas-Fermi (TF) calculations with use of the obtained energy of nuclear matter reproduce the gross feature of the experimental data on atomic nuclei. The nuclear species in the neutron star crust ...

International Nuclear Information System (INIS)

A scalar-relativistic procedure for calculating the valence-electron contribution to the total energy of bulk and thin-film solids has been developed and applied to the fcc and bcc phases of the group-VIB transition elements Cr, Mo, and W. This approach, which is based on the linear augmented-plane-wave method and local-density-functional theory, contains no shape approximations for either the charge density or potential. The formulation adopts a rigid-core approximation and incorporates an exact treatment of the core-charge tails that extend beyond the muffin-tin spheres. The application of this procedure to bcc Cr, Mo, and W yields calculated lattice parameters and bulk moduli that are in good (Cr) to excellent (Mo and W) agreement with experiment. The present calculated properties also agree quite well with the results of previous calculations involving a variety of band-structure methods. The ...

International Nuclear Information System (INIS)

This regulatory guide describes methods acceptable to the NRC staff for calculating radon fluxes through earthen covers and for calculating the resulting minimum cover thickness needed to meet NRC and EPA standards. The guide also suggests methods for obtaining the various parameters used in calculating the radon fluxes and earthen cover thicknesses and suggests default values for certain parameters. This regulatory guide is applicable to active uranium tailings sites. The NRC staff is using the methods stated in this guide as a basis for review and concurrence of DOE remedial action plans for inactive sites. The guidance is intended to be used for calculating radon flux attenuation by earthen uranium mill tailings covers. The parameter values and examples presented are limited to earthen cover materials, but the diffusion theory and the methods presented are also applicable to man-made materials. ...

International Nuclear Information System (INIS)

Accurate dose calculation in radiation treatment planning is most important for successful treatment. Since human body is composed of various materials and not an ideal shape, it is not easy to calculate the accurate effective dose in the patients. Many methods have been proposed to solve inhomogeneity and surface contour problems. Monte Carlo simulations are regarded as the most accurate method, but it is not appropriate for routine planning because it takes so much time. Pencil beam kernel based convolution/superposition methods were also proposed to correct those effects. Nowadays, many commercial treatment planning systems have adopted this algorithm as a dose calculation engine. The purpose of this study is to verify the accuracy of the dose calculated from pencil beam kernel based treatment planning system comparing to Monte Carlo simulations and measurements especially in inhomogeneous region. ...

International Nuclear Information System (INIS)

Based on the generalized gradient approximation (GGA) of density functional theory (DFT) and the full-potential linearized augmented plane wave (FLAPW) at the level including all electrons, the lattice parameters of graphite are calculated and optimized. Some elastic wave velocities transmitted in graphite are deduced. Using the methods of elastic wave velocity method and the atomic displacement method, the Debye frequency of graphite is obtained. The standard heat capacity, entropy, sublimation enthalpy of graphite is deduced at 289.5 k and 1 atm. The calculated results are discussed and compared with experimental data. (authors)

Energy Technology Data Exchange (ETDEWEB)

All sections of the third edition of this well-known textbook have been revised and enlarged in consequence of the change-over to SI units. Numerous examples and illustrations have been included or replaced by new ones. The book considers the latest research results as well as the constructive developments of industrial steam turbine construction. On a scientific basis, this plain book imparts basic knowledge of the design, calculation, execution, condensation and performance in service of steam turbines of all types. The well-founded introduction, together with many calculated examples addresses the student as well as the engineer.

Energy Technology Data Exchange (ETDEWEB)

Nuclear reaction cross-sections for stable strontium and cesium isotopes, which were calculated by different approaches, are compared to available experimental data. Neutron and proton induced reaction cross-sections for the long-lived radionuclides [sup 90]Sr and [sup 137]Cs have been calculated in the energy range from 1 MeV to 10 GeV. Recommendations concerning cross-section calculations for strontium and cesium isotopes at intermediate and high energies are given. (orig.)

International Nuclear Information System (INIS)

The global effect of activation cross-section uncertainties on calculated radiological quantities is investigated for the first time using a methodology based on Monte Carlo random sampling. The method is applied to the calculation of the uncertainty in the contact dose rate from the gunite shielding of the National Ignition Facility chamber after 30 yr of pulsed irradiation. Some critical cross section contributing significantly to the overall uncertainty are identified. By a reasonable reduction of the uncertainty in those cross sections, the accuracy in the calculated total contact dose rate is greatly improved.

International Nuclear Information System (INIS)

Local-density-approximation calculations of the H-point phonon frequency of molybdenum were carried out using a new superlinearized augmented-plane-wave basis. The calculated frequency is in quite good agreement with experiment. This indicates that the effect of the many-body renormalization of the electronic states near the Fermi energy on this frequency is smaller than previously suggested. The superlinearized basis and its use to circumvent computational difficulties associated with extended semicore states such as the 4p state of molybdenum is described.

International Nuclear Information System (INIS)

A calculation method of the X-ray radiation dose (energy of gamma- radiation remains in the range of energies where the mechanism of photoelectric absorption is the prevailing one) absorbed in the absorbers of final thickness is suggested. Calculations of resorption of secondary radiation (characteristic fluorescences) in the substance and kinetic energy of photoelectrons caused by this resorption (it would be enough to consider one or two hard series) are presented. Calculation of the spectrum of photoelectron energy yield in TeInSe_2 monocrystal for 0.1-0.5 A range of X-ray radiation is conducted by the developed methods.

Energy Technology Data Exchange (ETDEWEB)

Self-consistent electronic structure calculations have been performed on two compositions of scandium sulfide ScS and Sc/sub 3/S/sub 4/. The results of the calculation of ScS are similar to those obtained for other transition metal chalcogenides and are in excellent agreement with heat capacity and reflectance measurements as well as UPS experiments. The calculation of the defect structure indicates the creation of sulfur p nonbonding states in metal-deficient ScS. The valency of the metal ions remains unchanged upon the creation of vacancies.

Energy Technology Data Exchange (ETDEWEB)

Cross sections for the elastic and inelastic scattering of /sup 16/O on /sup 58/Ni, /sup 88/Sr, /sup 40/Ca, and /sup 48/Ca have been calculated in a coupled-channels treatment, including the low-lying 2/sup +/ and 3/sup /minus// states of both projectile and target. Real, energy-independent ion-ion potentials and form factors were used, and fusion was simulated by ingoing wave boundary conditions in all channels. The agreement with the measured scattering data is qualitatively as good as obtained in previous optical-model calculations.

Energy Technology Data Exchange (ETDEWEB)

Angular distributions for the elastic and inelastic scattering of /sup 12/C at 80 MeV by /sup 88/Sr and of /sup 7/Li at 36, 42 and 48 MeV by /sup 54/Fe have been analysed. The optical potentials of /sup 12/C and /sup 7/Li ions are calculated in terms of the alpha-particle and triton optical potentials. Coupled-channels calculations using these potentials are performed. Good fits to the experimental data and the phenomenological calculations are obtained for /sup 12/C projectiles.

Energy Technology Data Exchange (ETDEWEB)

A simplified relativistic configuration interaction method is used to study the dielectronic satellite transition processes. In this method, the infinite resonant doubly excited states can be calculated, and furthermore, the whole high-n dielectronic satellite transition processes can be treated conveniently by interpolation (rather than extrapolation) in the frame of quantum defect theory. As an example, we calculate the contributions from high-n dielectronic satellites to the K{alpha} resonance line in helium-like iron, and the results are in good agreement with the experimental measurements. (orig.) 39 refs.

Energy Technology Data Exchange (ETDEWEB)

This study is targeted to the NLO corrections of multileg processes, very important for the LHC. Starting from the construction of Feynman diagrams, the analytical reduction of general one-loop integrals to scalar master ones, the calculation of color structures, manipulation of spinor lines and other amplitude constituents and finally phase space point selection are obtained by use of a program producing Fortran code for numerical calculation of one-loop corrections for processes like gg{yields}t anti tgg. (orig.)

International Nuclear Information System (INIS)

A simple method allowing easy calculation of the spatial damage energy distributions for ion-implanted materials is presented. The direct procedure takes account of the variation with depth of the lateral spreading of implanted ions, as well as the effects of energy transport by the recoiling target atoms. The subsequent computer program LUPIN-3D provides three-dimensional damage distributions and allows the construction of damage energy mappings. Various substrates of technological interest are investigated and several fields of application of the calculation are envisaged. The density of cascades can therefore be determined and heterogeneous amorphization models can be implemented. (orig.).

International Nuclear Information System (INIS)

The energy-versus-volume curve of the spin-density wave (SDW) in body-centred-cubic Cr is calculated with the density functional theory/full-potential linearized augmented plane wave (DFT/FLAPW) method using the generalized gradient approximation (GGA). The predicted ground state is not the SDW, in contrast to an earlier FLAPW calculation. A conjecture is formulated that the widely varying results of the local density approximation (LDA) and GGA - and of different solution methods - can be scaled by the size of the calculated moment. As a consequence, experimentally relevant properties of the SDW can be calculated by tuning the moment. The implications of these results for the ability of DFT to describe Cr are discussed. (author)

CERN Document Server

Using the complex Kohn method, we have calculated variational values of phase shifts and the annihilation parameter, Z_{eff}, for the elastic scattering of positrons by molecular hydrogen. Our results are sensitive to small changes in the accuracy of the wave function representing the target hydrogen molecule. We have developed a systematic approach to demonstrate that, at low positron energies, there are particular forms of the Kohn trial wave function for which the results of variational calculations are not reliable, even when the target wave function accounts for as much as 96.8% of the correlation energy of H_{2}. We find that reliable results can be recovered if our calculations are extended to admit more sophisticated target wave functions accounting for 99.7% of the correlation energy. Remaining discrepancies between theory and experiment are briefly discussed.

Energy Technology Data Exchange (ETDEWEB)

We argue that the tachyons which exist in some string models are a signal of deconfinement. We compare the deconfinement temperature obtained from Monte Carlo calculations with some string models. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The performance of five well-known photosynthesis-light equations is compared by presenting a wide range of solutions in the form of dimensionless nomographs for the case where photosynthetically available radiation (PAR) reduces exponentially down the water column and is distributed sinusoidally through the photoperiod. These provide a simple means of calculating daily photosynthesis at any depth (e.g. at a benthic layer), or through a water column, avoiding the need to perform complex integrations. An examination is made of the accuracy of common approximate methods for calculating daily photosynthesis, assuming constant PAR. For optically deep water a modification is proposed to Talling's planimetric solution, to enable daily photosynthesis to be calculated more accurately, yet simply, over the whole range of possible PAR values. The errors induced by approximating the daily PAR distribution as a half-sinusoid ...

International Nuclear Information System (INIS)

The aim of the safety calculation is to quantify through numerical modelling the radiological impact (molar flow, human dose) of a potential repository for radioactive waste on the Meuse/Haute Marne site at Bure. A selection process is underway for safety scenarios and their phenomenological and numerical conceptual models upstream from the safety calculation. This involves defining and quantifying the geometric and dimensional representations of the repository for each scenario plus the physical, mathematical and numerical models that reflect its behaviour and the uncertainties associated with all the parameters required to quantify the impact. A summary will be given of these various aspects. The numerical simulations are then performed on the Alliances platform which integrates the various computer codes required for the physical representation of the system. (authors)

Science.gov (United States)

The workshop topics consist of FERS, FEGLI, FEHBP, Disability, Deposit/Redeposit ; TSP, Annual/Sick Leave, Annuity Calculation, Best Date to Retire, COLA's, ...

International Nuclear Information System (INIS)

In this work an analysis of the influence of the choice of the algorithm or planning system, on the calculus of the same treatment plan is introduced. For this purpose specific software has been developed for comparing plans of a series of IMRT cases of prostate and head and neck cancer calculated using the convolution, superposition and fast superposition algorithms implemented in the XiO 4.40 planning system (CMS). It has also been used for the comparison of the same treatment plan for lung pathology calculated in XiO with the mentioned algorithms, and calculated in the Plan 4.1 planning system (Brainlab) using its pencil beam algorithm. Differences in dose among the treatment plans have been quantified using a set of metrics. The recommendation for the dosimetrist of a careful choice of the algorithm has been numerically confirmed. (Author).

CERN Document Server

Monte Carlo calculations of proton irradiation of permanent magnets for the TRADE experiment have been performed. An irradiation dose of about 4´106 Gy/yr/mA has been estimated due to beam losses in normal operating conditions. Existing experimental results indicate that this irradiation level may induce a considerable demagnetization: in fact, a dose of 6´107 Gy induces a remanence loss of 0.3 % on samples of Sm2Co17 magnets, which are the most resistant type. More detailed calculations with the final design of the magnets and of the beam line are suggested, to determine if the irradiation levels allowed a reliable operation of the permanent magnets for the entire duration of the TRADE experiment. Damage and gas production rates have also been calculated; the values obtained are very low, thus confirming that the demagnetization process is in great part reversible.

International Nuclear Information System (INIS)

Nonrelativistic band calculations of Mattheiss for Nb and Petroff and Viswanathan for Mo are used to calculate the imaginary part epsilon_2 of the dielectric function for these metals. The structure resulting from interband transitions in the frequency range 0.1--0.5 Ry is found to give fairly good agreement with experiment. The calculation indicates that structure in epsilon_2 can arise from transitions away from symmetry points and lines in the Brillouin zone. The difficulty in distinguishing between the direct and indirect transition models for epsilon_2 is shown to arise from a lack of strong optical critical points. Predictions of the rigid-band model for the optical properties of Nb-Mo alloys are presented.

International Nuclear Information System (INIS)

An accurate neutronics calculation of a local thermal environment within a fast reactor presents a major challenge. A method was previously described that used Monte Carlo techniques within a macrocell to make accurate and reasonably efficient design calculations for such an environment. This method is now being further optimized for the calculation of "2"3"8Pu production in the Fast Flux Test Facility (FFTF). Here, it is not only important to determine the "2"3"8Pu production from neutron capture in "2"3"7Np, but also to calculate the production of the contamination isotope "2"3"6Pu from high-energy (n,2n) and (#gamma#,n) reactions. The power of the Monte Carlo method to automatically include geometry and energy self-shielding is retained by optimization using fission neutron source biasing in both space and energy.

Czech Academy of Sciences Repository

Full Text Available

International Nuclear Information System (INIS)

O.K. Andersen has recently introduced a linear augmented plane wave method (LAPW) for the calculation of electronic structure that was shown to be computationally fast. A more general formulation of an LAPW method is presented here. It makes use of a freely disposable number of eigenfunctions of the radial Schroedinger equation. These eigenfunctions can be selected in a self-consistent way. The present formulation also results in a computationally fast method. It is shown that Andersen's LAPW is obtained in a special limit from the present formulation. Self-consistent test calculations for copper show the present method to be remarkably accurate. As an application, scalar-relativistic self-consistent calculations are presented for the band structure of FCC lanthanum. (author).

Energy Technology Data Exchange (ETDEWEB)

There is no abstract currently available for this item

Science.gov (United States)

major radius of the toroidal containment volume. The containment time was calculated using equation (4) as derived in references 16 and 17. The solid ...

International Nuclear Information System (INIS)

We develop the notions of fusion for representations of the WA_2 algebra along the lines of Feigin and Fuchs. We present some explicit calculations for a WA_2 minimal model. (orig.).

CERN Document Server

The main topic of this thesis concerns efficient algorithms for the calculation of determinants of the kind of matrix typically encountered in lattice QCD. In particular an efficient method for calculating the fermion determinant is described. Such a calculation is useful to illustrate the effects of light dynamical (virtual) quarks. The methods employed in this thesis are stochastic methods, based on the Lanczos algorithm, which is used for the solution of large, sparse matrix problems via a partial tridiagonalisation of the matrix. Here an implementation is explored which requires less exhaustive treatment of the matrix than previous Lanczos methods. This technique exploits the analogy between the Lanczos tridiagonalisation algorithm and Gaussian quadrature in order to calculate the fermion determinant. A technique for determining a number of the eigenvalues of the matrix is also presented. A ...

Energy Technology Data Exchange (ETDEWEB)

This manual is presented in 8 chapters plus appendices. Chapters 1 and 2 are included as background information. The economic insulation thickness is found using the following chapters: Chapter 3, cost of energy (heat and refrigeration); Chapter 4, cost of insulation, and Chapter 5, economic thickness determination. Each of these chapters contains a worksheet, which provides a step-by-step procedure for solving the problem. Nomographs are included in each section for simplifying the required calculations. For subambient temperature systems, the economic insulation thickness calculated with Chapters 3 to 5 should be compared to the thickness required to prevent condensation (sweating), as calculated with Chapter 6. Chapter 7 presents the procedure for calculating economic insulation for retrofit situations. Sample problems are included in Chapter 8.

Energy Technology Data Exchange (ETDEWEB)

The relative abundances of iron-peak elements produced by the e-process in a supernova outburst are calculated. The results agree quite well with the cosmic abundances of elements in the range Z=23--28.

International Nuclear Information System (INIS)

The SCDAP computer code, which is being developed under the sponsorship of the United States Nuclear Regulatory Commission, models the progression of light water reactor core damage including core heatup, core disruption and debris formation, debris heatup, and debris melting. SCDAP is being used to help identify and understand the phenomena that control core behavior during a severe accident, to help quantify uncertainties in risk assessment analysis, and to support planning and interpretation of severe fuel damage experiments and data. Comparisons between SCDAP calculations and the experimental data showed good agreement. Calculated and measured bundle temperatures for SFD-ST were within 200 K for the entire bundle and within 20 K for maximum cladding temperatures. For ESSI-2, calculated and measured maximum cladding temperatures were within 50 K, and the extensive liquefaction and relocation that was ...

Energy Technology Data Exchange (ETDEWEB)

The increasing use of quantum-chemical methods in catalysis has underscored the importance of developing and improving semiempirical approximations oriented toward calculations of the total energy and geometry, offering a means for examining intermolecular interactions. In this article a general approach is proposed, using weighting factors for certain regions of distances, i.e., introducing different parametrization into the various regions. A scheme designated MINDO/3-HB is presented as an extension of the MINDO/3 scheme to the region of hydrogen bonds and ..pi..-complexes of olefins with Broensted acid centers (BACs). Examples of cluster calculations are given for the adsorption of ammonia, pyridine, ethylene, and ethanol on the BACs of zeolites. In the example of the process of zeolite synthesis, the possibilities of the cluster approach are discussed for calculations related to the formation of catalysts.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

Non-design-basis transition changes in the level fluctuations in the surrounds of a hot steam generator collector for a WWER-440 reactor and the corresponding responses of the temperature fields, strains and stresses are examined. A new approach to the thermal calculation of the horizontal steam generator, which is rapid and affords accurate results, is suggested. An important result of the calculation is the shape of the transition region level and the corresponding distribution of the heat transfer coefficient values. This was used for the calculation of the temperature fields, strain and stress of the hot collector. The stress values obtained were deeply below the yield point of the hot collector material but they get superimposed on the stress from overpressure in the primary and secondary circuits. The obtained fluctuations of the secondary medium level in the surrounds of the hot collector give rise to comparison ...

International Nuclear Information System (INIS)

... 5. Formation of the annular two-phase flow regime, with a wavy film on the

International Nuclear Information System (INIS)

The CERL Code was developed to describe the solution chemistry of the water on the steam generating side of PWR reactors. It is designed to calculate the equilibrium species distribution resulting from the interaction of impurities, corrosion products, and additives in the aqueous solution. It calculates the extent of ion-ion interactions, the precipitation of insoluble species and the amount of solute that partitions into the vapor phase when some of the water evaporates. This knowledge of the bulk phase equilibrium distribution of species, especially the pH should be useful in describing the corrosion processes at the solid liquid boundary. The code does not calculate any changes in oxidation states or any rates of reaction. Therefore, it is incapable of calculating the actual corrosion rates. It is anticipated that it will be used as a subprogram of a larger program that will include the redox ...

International Nuclear Information System (INIS)

(1 Aug 1972). United States Belakhovskii, M. Pierre, J. Ray, DK v.

Energy Technology Data Exchange (ETDEWEB)

A simple semianalytical calculation is used to study how a star reacts when its central stock of hydrogen is exhausted and before the next fusion reaction based on helium begins.

British Library Electronic Table of Contents (United Kingdom)

Abstract Electronic structures of two representative zigzag and armchair models of aluminum phosphide nanotube (AlPNT) were investigated by density functional theory calculations. The structures were optimized and the bond lengths, tip diameters, band gaps, and dipole moments were calculated. Moreover, the quadrupole coupling constants (CQ) were calculated for the Al-27 atoms of the optimized structures. The same values of AlP bond lengths were calculated for both models. The larger value of band gap of armchair model than the zigzag model indicated the stronger dielectric property for the former model. The values of CQ(27Al) were the largest for the Al atoms placed at the tips of both zigzag and armchair AlPNT than other Al atoms, which could reveal dominant role of the Al atoms placed at...

International Nuclear Information System (INIS)

Measurements of alpha spectra in the (n, #alpha#) reactions induced on /sup 90,91/Zr at 14.3 and 18.15 MeV incident neutron energy are presented. A microscopic calculation of these spectra has been made using both pick-up and knock-on theories, and in both cases only one overall normalizing factor, which is the same for the two target nuclei and incident energies and all the considered transitions, appears as a free parameter in the calculation. Pick-up calculations provide a very satisfactory reproduction of the data. Knock-on calculations reproduce many qualitative features of the measured spectra, but do not allow a fully satisfactory reproduction of them. While the results obtained do not exclude knock-on contributions to these reactions, their presence is not established.

Energy Technology Data Exchange (ETDEWEB)

Because of good thermal insulation of advanced energetic buildings and their good airtightness the air hygiene is insufficient. A normal ventilation behaviour by window opening consumes too much heating energy. A calculation method is shown taking into account a required air change number, flow rate and indoor air quality as thermal comfort in the rooms occupied by different number of persons. (GL)

Energy Technology Data Exchange (ETDEWEB)

Volume four contains calculations for: Borrow areas--site evaluation; temporary facilities--material quantities; embankment quantities--excavation and cover materials; Burro Canyon site excavation quantities--rippable and unrippable materials; site restoration--earthwork quantities and seeding; and bid schedule quantities and material balance.

Science.gov (United States)

A method is presented for calculating the thermal stability of blast furnace coke over a wide range of sizes, based on a study of the coke behaviour pattern in the blast furnace and the change in its thermo-elastic properties during reheating. Using as an example a Novolipetsk metallurgical plant, the possibility was demonstrated of using the thermal stability index calculated by the proposed method for an unambiguous assessment of the quality of blast furnace coke.

Energy Technology Data Exchange (ETDEWEB)

The nuclear shapes of transitional Mo isotopes are calculated by means of a model based on the cranking approximation and the Strutinksy method. The recent experimental results of the high-spin spectroscopy and lifetime measurement of [sup 87]Mo are studied in detail and explained by the evolution of the [gamma]-deformation with the quasiparticle configurations. The shape calculations with the modified-harmonic-oscillator potential give a critical neutron number N [>=] 47 for the spherical shape of the Mo isotopes. (orig.)

Energy Technology Data Exchange (ETDEWEB)

In this work, the thermodynamic behaviour of single-stage horizontal spray coolers with one or more spray levels is experimentally examined. Further, a spray cooler calculation model was developed, in order to describe the processes and to make a comparison of the results of calculation and measurement. The state of the mine climate and the cold water are taken as the thermodynamic reference. (orig.).

Energy Technology Data Exchange (ETDEWEB)

In this article, the results of low-current gas-discharge plasma generator investigations carried out by a group of scientists from the Kazan' Aviation Institute are presented. When considered necessary, the results are compared with the data obtained by other authors. The basic configurations and theoretical calculation peculiarities of plasma generators are described. The electrical, thermal and energy characteristics of discharges in gas flows, as well as summarised empirical formulae and experimental data necessary for calculations and design of plasma devices are presented. (author)

International Nuclear Information System (INIS)

This paper describes the modeling of horizontal steam generator with the TRACE code and calculation results of a loss-of-feedwater (LOF-10) experiment at the PACTEL facility. Parallel Channel Test Loop (PACTEL) is an integral test facility for a VVER-440 type nuclear reactor. The main objectives were to prepare a simulation model for its horizontal steam generator with the TRACE thermal hydraulic code and assess different modeling options of the code. PACTEL experiment LOF-10 was chosen for this assessment. The calculation results showed that TRACE is capable in simulating horizontal steam generator behavior both in steady state and during loss-of-feedwater transient. The phenomenon of heat transfer from primary to secondary side, steam superheating and flow reversal in the lowest heat exchange tubes were studied in detail. Different nodalization options were introduced. In the simulation of PACTEL loss-of-feedwater experiment LOF-10, the main ...

International Nuclear Information System (INIS)

The properties of "1"7"7Ta and sup(181, 182, 187)Re states are discussed in the framework of the rotational model with the Coriolis coupling. The relations are obtained for calculating magnetic moments by this model in the jlK representation. The valent-nucleon spin polarization found on the basis of a comparison of the experimental values of magnetic moments with the calculated ones, is shown to depend on the number of nucleons of the same type.

Energy Technology Data Exchange (ETDEWEB)

Certification as applied to existing computer codes includes the verification and validation process, placing the code in configuration control, establishing user qualification standards and training requirements. All software intended for use in critical calculations must be certified. This report is intended to fulfill the requirements for the certification of the SHIELD, SHLDED, GEDIT, GENPRT, FIPROD, FPCALC, and PROCES modules of the SHIELD system built February, 1992, by W.S. Parks. These modules are used for burnup, cooling, separate, and edit calculations.

Energy Technology Data Exchange (ETDEWEB)

The effective half-life based on urine bioassay results of Wolsung NPP's worker was calculated. The effective half-life for tritiated water vapour obtained was 5 {approx} 9 days. In comparison to 10 days reported for ICRP-30, it is lower than the corresponding half-life for Reference Man. Also, the half-life was calculated based on intake amount of daily water. According to this result, the metabolism was reviewed.

CERN Document Server

The Rayleigh scattering length has been calculated for rare-gas liquids in the ultraviolet for the frequencies at which they luminesce. The calculations are based on the measured dielectric constants in the gas phase, except in the case of xenon for which measurements are available in the liquid. The scattering length mayplace constraints on the design of some large-scale detectors, using uv luminescence, being proposed to observe solar neutrinos and dark matter. Rayleigh scattering in mixtures of rare-gas mixtures is also discussed.

CERN Document Server

We combine a limited number of accurately measured transition frequencies in hydrogen and deuterium, recent quantum electrodynamics (QED) calculations, and, as an essential additional ingredient, a generalized least-squares analysis, to obtain precise and optimal predictions for hydrogen and deuterium transition frequencies. Some of the predicted transition frequencies have relative uncertainties more than an order of magnitude smaller than that of the g-factor of the electron, which was previously the most accurate prediction of QED.

Energy Technology Data Exchange (ETDEWEB)

The electron scattering form factor for excitation of the 1/sup +/ state of /sup 88/Sr at 3.486 MeV has been calculated in the quasiparticle random phase approximation (QRPA). The disagreement between the data and restricted shell-model calculations can be explained in terms of the pairing correlations introduced by the QRPA; no ..delta..-h admixtures are required.

International Nuclear Information System (INIS)

The capture cross sections of Am 242m can be deduced from resonances analysis at low energy and computed with theoretical models at high energy. In this work, a coherent set of cross sections which reproduced the experimental values of the fission cross sections is computed. These calculations were performed for an energy of the incoming neutron between 1 keV and 1 MeV.

International Nuclear Information System (INIS)

Analytical expression of the dependence of freezing temperature of electrolyte (CdCl_2, CdSO_4, BeSO_4) aqueous solutions on their composition was found. Three different methods were suggested were suggested for calculation of water activity in multicomponent solution. It was established that sublinear extrapolation of freezing temperature of salt aqueous solutions was possible not up to -5 deg C, but up to -15 deg C, independently of their composition. 6 refs.; 2 figs.

Energy Technology Data Exchange (ETDEWEB)

To determine the transient response of linear and time-invariant transmission systems which are only described for discret frequencies, it is possible to find a good functional approximation by means of the generalized impulse method, combined with the most important natural spline-interpolation functions of the first and the third degree. This procedure has been applied to calculate the step response of the transient behaviour of the zero-sequence impedance system of the high voltage transmission line.

Energy Technology Data Exchange (ETDEWEB)

The Monte Carlo simulation method is applied to calculate the nucleon transfer part of the imaginary optical-model potential in colliding heavy ions. In the process of transfer of nucleons from one nucleus to the other, forward and backward neutrons and protons are treated separately by taking into consideration the effect of the Coulomb forces and the potential energy surfaces (driving forces). The Pauli exclusion principle is also incorporated properly in the calculation.

International Nuclear Information System (INIS)

Results of calculation of steady thermal-hydraulic characteristics of PVG-440 horizontal steam generator are presented. Steam flows in selected sections are compared to data provided by OKB Gidropress Calculated vapor void fractions are compared to measured ones. (orig.) (3 refs., 3 figs., 8 tabs.).

British Library Electronic Table of Contents (United Kingdom)

The thermodynamic characteristics of adsorption of proline and its hydroxy derivatives on the surface of graphitized thermal carbon black (GTCB) were calculated. The arrangement of hydroxyl groups in the amino acid molecule was shown to influence their adsorption on GTCB. The influence of internal rotation angles in proline and its hydroxy derivative molecules on their adsorption on GTCB was studied.

International Nuclear Information System (INIS)

An alternative and graphical representation of the magnetic moment and the effective paramagnetic moment for polycrystalline Ce compounds with tetragonal site symmetry is described. The reduced moments can be calculated by means of standard perturbation theory. The calculated values deduced from the ground states of CeCu_2Si_2, CeRu_2Si_2, and CePd_2Si_2 polycrystals are compared with experimental magnetic moments.

Energy Technology Data Exchange (ETDEWEB)

A numerical calculation procedure applicable to cavity-type receiver configurations and flow conditions was developed. Flow visualization experiments were performed, and experimental measurements of quantities valuable for the development of the numerical calculation procedure were made. The investigation is focussed on a configuration which is strongly two-dimensional in the mean flow structure (but turbulent in a truly three-dimensional sense). (LEW)

International Nuclear Information System (INIS)

In radiotherapy treatment planning, convolution/superposition algorithms currently represent the best practical approach for accurate photon dose calculation in heterogeneous tissues. In this work, the implementation, accuracy and performance of the FFT convolution (FFTC) and multigrid superposition (MGS) algorithms are presented. The FFTC and MGS models use the same 'TERMA' calculation and are commissioned using the same parameters. Both models use the same spectra, incorporate the same off-axis softening and base incident lateral fluence on the same measurements. In addition, corrections are explicitly applied to the polyenergetic and parallel kernel approximations, and electron contamination is modelled. Spectra generated by Monte Carlo (MC) modelling of treatment heads are used. Calculations using the MC spectra were in excellent agreement with measurements for many linear accelerator types. To speed up the ...

International Nuclear Information System (INIS)

The results of the development work to improve the horizontal steam generator modelling using the CATHARE code as well as the results of the steady-state and the steam-line break calculations are presented. Also the results of the steady-state calculations are compared to the measurements performed in operating VVER power plants. (9 refs., 6 figs., 2 tabs.).

International Nuclear Information System (INIS)

The governor model is extended to include the asymmetric shape of nuclei which allows a simultaneous analysis of the data for both the ground state and the #gamma#-vibrational bands in deformed even-even nuclei. The rotationally invariant core is assumed to be a spheroid with an axis of symmetry parallel to the axis of rotation. The calculations are carried out under the assumption of no stretching. The static #gamma#-deformation results are compared with the VMI(ARM) and Krutov values, and the calculated energies are in good agreement with the experimental data.

Energy Technology Data Exchange (ETDEWEB)

We report on the calculation of multi-loop Feynman integrals for single-scale problems by means of difference equations in Mellin space. The solution to these difference equations in terms of harmonic sums can be constructed algorithmically over difference fields, the so-called {pi}{sigma}{sup *}-fields. We test the implementation of the Mathematica package Sigma on examples from recent higher order perturbative calculations in Quantum Chromodynamics. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Calculations of total and angle-differential excitation cross sections for the electron impact excitation of lithium-like iron were performed with the R-matrix formulation. The alignments of the excited states 1s{sup 2}np {sup 2}P{sub 3/2} are also presented for n=3 and 4 along with the angular photon distribution from these states to the ground state. Relativistic effects were included in the present calculations by the Breit-Pauli Hamiltonian.

International Nuclear Information System (INIS)

A new approach is introduced to study QCD amplitudes at high energy and comparatively small momentum transfer. Novel cut diagrams, representing the resummation of Feynman diagrams, are used to simplify the calculation and to avoid delicate cancellations encountered in the usual approach. An explicit calculation to the sixth order is carried out to demonstrate the advantage of cut diagrams over Feynman diagrams. copyright 1996 The American Physical Society.