Maximum Volume Increase Research Articles

WATER-SWELLING ELASTOMERS BASED ON ETHYLENE-PROPYLENE RUBBER

This paper is dedicated to the investigation of water- and oilswelling ability of the elastomeric material based on nonpolar ethylene-propylene rubber, modified by water swelling agents such as combination of copolymer acrylamide with potassium acrylate and sodium-carboxymethyl cellulose. It was found that the maximum volume increase of the sample recorded during it`s exposure in water and is equal 1250 %, in 10 % and 22 % aqueous solutions of sodium chloride is up to 280 % and 210 %, in oil and the Polyekonol-Flora drilling system 70 % and 80 %, respectively.

Clitoria ternatea anthocyanin extract suppresses inflammation in carrageenaninduced rat paw edema via down-regulating genes of phosphoinositide 3-kinase signaling pathway

Inflammation is characterized by an increase in vascular permeability leading to edema formation. Phosphoinositide 3-kinase (PI3K) signaling pathway plays the main role to regulate several key events in the inflammatory response to damage and infection. Our previous in silico study showed that anthocyanin and ternatin flavonoids may offer antiinflammatory potential via molecular docking model. Here, we explored whether Clitoria ternatea anthocyanin extract (CTA) had protective activity against inflammation via regulating gene expression related to PI3Ks in rat edema. CTA was extracted in methanol and acetone using maceration and lyophilization. Edema model was done by injecting carrageenan into rat paw. Oral supplementation of CTA (100, 250, and 500 mg/kg BW) and ibuprofen standard (15 mg/kg BW) was given to rats daily for 7 days. After sample treatment, the right hind paw of the rat was injected with carrageenan to induce edema condition. The ability of CTA to suppress the inflammation in paw edema was measured by quantifying the increased percentage of rat paw volume at 1, 3, and 5 hrs after injection. Rat paw tissue was collected, and gene expression related to PI3Ks, i.e. Akt1, PKB, Ilk, Pdk2, Pik3Ca, and p53 was determined using quantitative PCR (qPCR). Carrageenan showed a time-dependent increase in volume of rat paw starting from injection until the next 5 hrs. It reached maximum volume increase of rat paw at 3 hrs after injection. CTA treatment had a dose-dependent pattern in reducing the edema volume in carrageenan-induced paw edema. At 500 mg/kg BW, CTA significantly suppressed the inflammation in paw edema compared to that of positive control, indicating by the low percentage of paw edema volume at 1, 3, and 5 hrs after carrageenan injection. At gene level, qPCR data showed that CTA significantly down-regulated the expression of genes involved in PI3Ks, such as Akt1, PKB, Ilk, Pdk2, Pik3Ca, and p53 in paw tissues. Thus, CTA may have a protective effect against edema via suppressing genes of PI3Ks.

The Effect of Minimally Invasive Surgical Repair on the Lung Volumes of Patients with Pectus Excavatum

To assess the increase in lung volume after Nuss surgery in patients with pectus excavatum (PE) by using stereological methods and to evaluate the correlation between the lung volume and spirometry findings. Twenty patients, treated for PE between 2008 and 2010, were evaluated prospectively. They underwent preoperative chest radiography, computed thorax tomography (CTT), and spirometry. Thereafter, the Haller index was calculated for each patient. In the third postoperative month, CTT and spirometry were repeated.Lung volumes and volume fractions were evaluated using CTT images, applying the Cavalieri principle for stereological methods. Then the correlation between the pre- and postoperative values of the lung volumes with spirometry findings was determined. Volumes of the right and left lungs were calculated stereologically, using CTT images. Postoperative volume increase of ∼417.6 ± 747.6 mL was detected. The maximum volume increase was observed in the left lung. In the postoperative period, the total volume increase and the volume increase detected in the left lung were found to be statistically significant (p < 0.05).The preoperative correlation coefficients (r) for forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow 25 to 75% were 0.67, 0.68, and 0.61, respectively; the postoperative r figures were 0.43, 0.42, and 0.35, respectively. Although there was a strong correlation between the preoperative lung volume and spirometry findings (p < 0.05), no correlation was observed between the postoperative lung volume and spirometry findings (p > 0.05). Postoperative pulmonary volume increase occurs in patients with PE after Nuss surgery. However, postoperative spirometry findings may not reflect morphological improvement because pain restricts thoracic movements. Therefore, in patients with PE, quantitative evaluation of the results of surgical repair is possible using the CTT images through a combination of stereological methods.

1143 A REAL-TIME MOTION ANALYSIS OF PENILE ERECTION WITH TURBO-FLASH MR IMAGING SYSTEM

You have accessJournal of UrologySexual Function/Dysfunction/Andrology: Evaluation I1 Apr 20121143 A REAL-TIME MOTION ANALYSIS OF PENILE ERECTION WITH TURBO-FLASH MR IMAGING SYSTEM Jintetsu Soh, Noriyuki Kanemitsu, Atsushi Ochiai, Yasuyuki Naitoh, Yoshio Naya, kazumi Kamoi, Akihiro Kawauchi, and Tsuneharu Miki Jintetsu SohJintetsu Soh Kyoto, Japan More articles by this author , Noriyuki KanemitsuNoriyuki Kanemitsu Kyoto, Japan More articles by this author , Atsushi OchiaiAtsushi Ochiai Kyoto, Japan More articles by this author , Yasuyuki NaitohYasuyuki Naitoh Kyoto, Japan More articles by this author , Yoshio NayaYoshio Naya Kyoto, Japan More articles by this author , kazumi Kamoikazumi Kamoi Kyoto, Japan More articles by this author , Akihiro KawauchiAkihiro Kawauchi Kyoto, Japan More articles by this author , and Tsuneharu MikiTsuneharu Miki Kyoto, Japan More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2012.02.1253AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES There have been no reports of real-time image analysis in the corpus cavernosum from the initiation to the end of erection without artificial induction. Using Turbo-FLASH MRI, we were able to obtain a series of high resolution images through tumescence, maintenance and detumescence phases of erection. The aim of this study was to analyze the dynamic morphological changes in the penis during a normal erection. METHODS The participants in this study included 5 healthy volunteers without experience of erectile dysfunction. Ages ranged from 22 to 47 (median 33) years. IIEF-5 score ranged from 22 to 25 (median 23) points. Audio-visual sexual stimulation was used to induce erection. MRI was conducted using Siemens MAGNETOM Sonata 1.5T with body array and spine coils. True-FISP sequence was used with conditions of TR: 4.38 ms, TE: 2.19 ms, and scan time: 0.85 sec/slice. Using dynamic images, the volume of the corpus cavernosum within the tunica albuginea were consecutively calculated by measuring length, width, and thickness in sagittal and coronal section during all phases of a normal erection (Figure 1). Morphological changes were evaluated with indices including the maximum changes in the volume between latent and full erection phases of the corpus cavernosum as well as the consecutive volume increase rate per second. RESULTS From initiation to completion of erection, range of time required from 110 to 120 (median 115) seconds, changes in volume of corpus cavernosum ranged from 28 to 35 (median 32) ml. Maximum volume increase rate ranged from0.5 to 0.8 (median 0.66) ml/sec (Figure 2). CONCLUSIONS By using Turbo-FLASH MRI, dynamic phases of a normal erection can be analyzed calculating the maximum changes in volume of corpus cavernosum as well as volume increase rate per second. Further study is warranted to prove these novel parameters as a measurement of vascular function. © 2012 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 187Issue 4SApril 2012Page: e463-e464 Advertisement Copyright & Permissions© 2012 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jintetsu Soh Kyoto, Japan More articles by this author Noriyuki Kanemitsu Kyoto, Japan More articles by this author Atsushi Ochiai Kyoto, Japan More articles by this author Yasuyuki Naitoh Kyoto, Japan More articles by this author Yoshio Naya Kyoto, Japan More articles by this author kazumi Kamoi Kyoto, Japan More articles by this author Akihiro Kawauchi Kyoto, Japan More articles by this author Tsuneharu Miki Kyoto, Japan More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Influence of the 5‐HT3 receptor antagonist ondansetron on gastric sensorimotor function and nutrient tolerance in healthy volunteers

Serotonin is believed to be involved in the regulation of the gastric accommodation reflex in man however which receptor subtype(s) are involved remains to be elucidated. Eleven healthy subjects (nine men, age 19-30) underwent a gastric barostat and a drinking test after treatment with either placebo or ondansetron (8 mg intravenously). During the barostat protocol an intragastric flaccid bag was stepwise distended (2 mmHg increments 2 min) to determine gastric compliance and sensitivity to distention. Subsequently, the pressure level was set at intra-abdominal pressure +2 mmHg while volume was followed before and after administration of a liquid meal (200 mL; 300 kcal). During the drink test volunteers drank at a rate of 15 mL min(-1) until maximal satiation. Results (mean ± SEM) were compared using t-tests and mixed model analysis. Gastric compliance was not significantly altered by ondansetron (51.5 ± 5.6 vs 49.2 ± 5.2 mL mmHg(-1)), neither were the pressure thresholds for first perception or discomfort. Ondansetron treatment did not affect basal gastric tone (173 ± 14 vs 156 ± 12 mL), neither did it affect the amplitude of the meal-induced relaxation (160 ± 52 vs 131 ± 43 mL) or the maximum volume increase after the meal (264 ± 54 mL vs 234 ± 51 mL). During the drinking test the amount of liquid meal ingested at maximum satiation was significantly increased by ondansetron (784 ± 74 vs 907 ± 64 mL, P < 0.05). These data suggest that 5-HT acting at 5-HT(3) receptors is not involved in the control of gastric sensorimotor function, but contributes to the regulation of hunger and satiation in man.

The effects of acute citalopram dosing on gastric motor function and nutrient tolerance in healthy volunteers

It is unclear whether endogenous serotonin release is involved in the regulation of gastric motility and food intake. To study the effect of acute administration of the selective serotonin reuptake inhibitor citalopram on gastric motor function in man. Nineteen healthy volunteers underwent a gastric barostat, gastric emptying and/or a drinking test after dosing with either placebo or citalopram (20 mg intravenously). In the barostat protocol, a flaccid bag was introduced in the stomach and inflated at intra-abdominal pressure +2 mmHg, volume was recorded before and after administration of a liquid meal (300 kcal). Gastric emptying for solids and liquids was simultaneously assessed using the ¹⁴C-octanoic acid/¹³C-glycine breath test. During the drink test, volunteers drank at a rate of 15 mL/min until maximal satiation. Citalopram was compared with placebo using t-tests and mixed model analysis. Citalopram induced a significant preprandial gastric relaxation (volume increase of 154 ± 55 mL vs. -38 ± 33 mL after placebo dosing; P < 0.05), whereas the postprandial volume increase was significantly decreased after citalopram treatment (F₁₂.₈₀ = 4.78, P < 0.0001; maximum volume increase was 304 ± 40 vs. 201 ± 54 mL after placebo and citalopram treatment respectively). Citalopram enhanced solid (123 ± 17 vs. 77 ± 6 min, P < 0.05) but not liquid emptying (62 ± 6 vs. 57 ± 4 min). Satiation scores during the drink test were lower after citalopram (F₁₉.₁₅₃ = 2.02, P = 0.01; volunteers drank 998 ± 129 vs. 765 ± 79 mL after citalopram and placebo treatment respectively). The observed effects indicate a role for serotonin in the control of gastric motility and food intake.

“Breathing” in Adsorbate‐Responsive Metal Tetraphosphonate Hybrid Materials

The structures of various layered calcium tetraphosphonates (CaH6DTMP; H8DTMP=hexamethylenediamine tetrakis(methylenephosphonic acid)), have been determined. Starting from CaH6DTMP.2H2O, thermal treatment and subsequent exposure to NH3 and/or H2O vapors led to four new compounds that showed high storage capacity of guest species between the layers (up to ten H2O/NH3 molecules) and a maximum volume increase of 55 %. The basic building block for these phosphonates consists of an eight-membered ring chelating Ca2+ through two phoshonate groups, and the organic ligand is located within the layers, which are held together by hydrogen bonds. The structural analysis revealed that the uptake/removal of guest species (H2O and NH3) induces significant changes in the framework not only by changing the interlayer distances but also through important conformational changes of the organic ligand. An anisotropic breathing motion could be quantified by the changes of the unit-cell dimensions and ligand arrangements in four crystalline derivatives. Complete characterization revealed the existence of interconversion reactions between the different phases upon gas uptake and release. The observed behavior represents, to the best of our knowledge, the first example of a breathing-like mechanism in metal phosphonates that possess a 2D topology.

Transient expansion of vestibular schwannoma following stereotactic radiosurgery

The authors prospectively analyzed volume changes in vestibular schwannomas (VSs) after stereotactic radiosurgery. One hundred consecutive patients with unilateral VS treated with Gamma Knife surgery (GKS) at Chiba Cardiovascular Center between 1998 and 2006 were analyzed in this study. For each lesion the Gd-enhanced volume was measured serially every 3 months in the 1st year, then every 6 months thereafter, using volumetric software. The frequency and degree of transient tumor expansion were documented and possible prognostic factors were analyzed. Concurrently, neurological deterioration involving trigeminal, facial, and cochlear nerve functions were also assessed. The mean observation period was 65 months (range 25-100 months). There were 32 men and 68 women, whose mean age was 59.1 years (range 29-80 years). Tumor volumes at GKS averaged 2.7 cm3 (range 0.1-13.2 cm3), and the lesions were irradiated at the mean 52.2% isodose line for the tumor margin (range 50-67%), with a mean dose of 12.2 Gy (range 10.5-13 Gy) at the periphery. The tumor volume was increased by 23% at 3 months and 27% at 6 months. Tumors shrank to their initial size over a mean period of 12 months. The maximum volume increase was < 10% (no significant increase) in 26 patients, 10-30% in 23, 30-50% in 22, 50-100% in 16, and > 100% in 13. The peak tumor expansion averaged 47% (range 0-613%). A high-dose (> or = 3.5 Gy/min) treatment appears to be the greatest risk factor for transient tumor expansion, although the difference did not reach statistical significance. Transient facial palsy and facial dysesthesia correlated strongly with tumor expansion, but only half of the hearing loss was coincident with this phenomenon. Transient expansion of VSs after GKS was found to be much more frequent than previously reported, strongly suggesting a correlation with deterioration of facial and trigeminal nerve functions.

Improving the Cure Rate of Alarm Treatment for Monosymptomatic Nocturnal Enuresis by Increasing Bladder Capacity—A Randomized Controlled Trial in Children

We prospectively assessed response and cure rates of alarm treatment, following pretreatment with antimuscarinics and/or holding exercises aimed at increasing maximum volume voided in 149 children with monosymptomatic nocturnal enuresis. In a prior trial the same 149 children had been randomized into 5 groups to assess interventions for increasing maximum volume voided, namely placebo or antimuscarinics with (groups A and B, respectively) and without (C and D, respectively) holding exercises, and a control group (E) receiving just alarm treatment. Following pretreatment groups A to D received alarm treatment. Full response and cure rates were assessed, as well as the influence on these rates of baseline maximum volume voided, increase in maximum volume voided after pretreatment, gender, age and previous treatment. Neither full response nor cure was influenced significantly by the increase in maximum volume voided achieved in groups A and B with holding exercises. Overall full response ranged from 50% to 73%, and overall cure ranged from 50% to 67%. Possible predictors for full response and cure were prior treatment (p <0.02) and age younger than 8 years (p <0.05). In monosymptomatic nocturnal enuresis increasing maximum volume voided does not affect response or cure rate of subsequent alarm treatment. Previous treatment and age younger than 8 years are possible predictors for response and cure.

Inflation of the Aira Caldera (Japan) detected over Kokubu urban area using SAR interferometry ERS data

Nine ERS-1 and ERS-2 descending orbit data ac- quired over Aira Caldera between June 1995 and November 1998 were used to create 36 differential interferograms. Al- though the interferograms exhibit a relatively low level of coherence, even for couples sampling short time intervals (6 months), Synthetique Aperture Radar (SAR) observations re- veal a distinct range change pattern over Kokubu urban area whose amplitude increases with the time separation between SAR images. The analysis of the ground deformation time series relative to the earliest ERS images showed a maxi- mum uplift of about 20 mm between the north and the south of the urban area during the period covered by our satellite observations. Taking the reduced surface of the coherent area into account, we performed a simple modeling of the defor- mation field assuming an inflating spherical source within an elastic half-space medium located beneath the centre of the Aira Caldera. This simple model predicts a maximum volume increase of 20-30◊10 6 m 3 between 1995 and 1998, which would produce an inflation of about 70 mm at the cen- tre of the Aira Caldera and 40 mm in the Kokubu south urban area. These results are in good agreement with other geo- physical observations carried out on the Aira caldera during this period. Despite the limited spatial extent of the coherent areas around the Aira Caldera, this study shows that Din- SAR method using data collected in C band can be success- fully used to detect subtle ground displacement changes of the volcanic complex and thus provides complementary in- formation to ground-based geodetic monitoring of dynamic processes of the Aira Caldera and Sakurajima volcano.

A proposed mechanism of high-temperature puffing of potato. Part I. The influence of blanching and drying conditions on the volume of puffed cubes

Potato cubes were blanched and partially dried in a cabinet drier prior to puffing in a Torbed 500, high-temperature fluidised bed drier. It was established that formation of a partially dried layer (PDL) on the surface of the cubes was necessary to achieve puffing. The influence of blanching and drying conditions on this layer was investigated. It was concluded that blanching for 2 min in water at 100°C followed by drying in air at 90°C for 40 min resulted in the maximum increase in volume of the puffed cubes.

Proximal gastric motor activity in response to a liquid meal in type I diabetes mellitus with autonomic neuropathy.

Disordered gastric emptying occurs in 30-50% of patients with diabetes mellitus. Although the rate of gastric emptying is dependent on the integration of motor activity in different regions of the stomach, there is limited information about the function of the proximal stomach in diabetes mellitus. In the present study the response of the proximal stomach to a liquid meal was examined in eight diabetic patients with autonomic neuropathy and gastrointestinal symptoms and in 10 healthy volunteers, using an intragastric bag connected to an electronic barostat. Postprandial relaxation of the proximal stomach was measured as an increase of intragastric bag volume at a constant pressure level of 1 mm Hg above the intraabdominal pressure. During the experiment the blood glucose levels were maintained within the euglycemic range. Before ingestion of the meal the intragastric bag volume was larger in the diabetic patients than in the healthy volunteers, 234.4 +/- 29.1 ml vs 155.3 +/- 15.3 ml (P = 0.06). The maximum volume was not different in diabetics compared to the healthy controls (386.3 +/- 45.2 ml versus 399.0 +/- 35.2 ml). However, the maximum volume increase was significantly less in diabetics (143.7 +/- 38.6 ml) compared to the controls (231.4 +/- 30.5 ml, P < 0.04). Bloating was inversely correlated with the volume changes, which suggests that impaired relaxation of the proximal stomach may play a role in the genesis of this sensation. In conclusion, this study shows a lower fasting fundal tone and a decrease in volume change of the gastric fundus after a nutrient drink in patients with autonomic neuropathy due to type I diabetes mellitus. These abnormalities may play a role in the abnormal distribution of food, disordered liquid gastric emptying, and in the genesis of the sensation of bloating observed in these patients.

Swelling Behaviour of the Catch Connective Tissue In Holothurian Body Wall

ABSTRACT Swelling tests in a series of isotonic and isoionic solutions of varying calcium-to-sodium ratios were conducted on isolated dermal connective tissue of the holothurian Thyonella gemmata Verrill. The tissue swelled rapidly and attained a maximum volume increase of approximately 40 % when transferred from distilled water to NaCl solution; however, the volume did not change significantly in isotonic CaCl2 solution. At Ca2+/Na+ ratios ⩽0·04 the tissue swelled at its maximum rate. The rate decreased with increasing calcium concentration, until at Ca2+/Na+ ⩾0·40 no detectable swelling occurred. Similar results were obtained for Pentacta pygmaea Goldfuss. When tissues previously swollen in NaCl were placed in CaCl2, the volume decreased significantly. Uniaxial tensile tests indicated that the elastic modulus of the tissue was much greater in Ca2+ solutions than in Na+ solutions. We hypothesize that dermal stiffness in holothurians is regulated by cation-sensitive crosslinks.

Left atrial volume changes in mitral valve disease: a cross-sectional echocardiographic study.

We used cross-sectional echocardiography to study left atrial volume changes in 25 patients with mitral valve disease who underwent cardiac catheterisation. Satisfactory 4 chamber views were obtained in 21. Left atrial systolic overload measured as systolic expansion index did not correlate with the severity of mitral regurgitation as assessed by contrast ventriculography and indicator dilution. The left atrial systolic expansion rate, and the maximum volume increase during the first third of systole, measured as the early systolic expansion index, differentiated well between moderate and severe mitral regurgitation, but not between trivial and moderate regurgitation. Calculation of the early systolic expansion fraction (fraction of total expansion occurring in the first third of systole) gave the best correlation with the degree of mitral regurgitation estimated by other methods.

Diurnal Changes in Volume and Specific Tissue Weight of Crassulacean Acid Metabolism Plants

The diurnal variations in volume and in specific weight were determined for green stems and leaves of Crassulacen acid metabolism (CAM) plants. Volume changes were measured by a water displacement method. Diurnal variations occurred in the volume of green CAM tissues. Their volume increased early in the light period reaching a maximum about mid-day, then the volume decreased to a minimum near midnight. The maximum volume increase each day was about 2.7% of the total volume. Control leaves of C(3) and C(4) plants exhibited reverse diurnal volume changes of 0.2 to 0.4%. The hypothesis is presented and supported that green CAM tissues should exhibit a diurnal increase in volume due to the increase of internal gas pressure from CO(2) and O(2) when their stomata are closed. Conversely, the volume should decrease when the gas pressure is decreased.The second hypothesis presented and supported was that the specific weight (milligrams of dry weight per square centimeter of green surface area) of green CAM tissues should increase at night due to the net fixation of CO(2). Green CAM tissues increased their specific weight at night in contrast to control C(3) and C(4) leaves which decreased their specific weight at night. With Kalanchoë daigremontiana leaves, the calculated increase in specific leaf weight at night based on estimates of carbohydrate available for net CO(2) fixation was near 6% and the measured increase in specific leaf weight was 6%.Diurnal measurements of CAM tissue water content were neither coincident nor reciprocal with their diurnal patterns of either volume or specific weight changes.

Void formation in an Al-Mg-Si alloy under different precipitation conditions after irradiation with 100 keV Al ions

The influence of different precipitation treatments upon the radiation-induced void formation was studied on an Al-Mg-Si alloy and the results were compared with those obtained on high-purity Al. The changes in the microstructure and the void formation were investigated by TEM methods for the dose range 0.8 to 80 dpa and the temperature range 55 to 250° C. The irradiations were carried out using 100 keV Al ions. Highpurity Al showed void formation over the whole temperature range investigated with a maximum volume increase ΔV/V of 3.4% at 150° C. The behaviour of the Al-Mg-Si alloys depends strongly upon the thermal pretreatments. The alloy in its homogenized state shows no voids between 55 and 140° C. Trapping of vacancies on solute Si atoms could be the explanation. An ageing treatment leading to coherent precipitates results in the complete suppression of void formation for the temperature region of highest swelling (0.35 Ts⩽T⩽0.44 Ts). On the other hand, treatments which cause incoherent or partially coherent precipitates result in swelling. The amount of swelling, however, is lower compared to pure Al and the temperature of the swell maximum is shifted to lower temperatures. These results could be explained by the mechanism of trapping vacancies by solute atoms, on the one hand, and the coherent precipitates acting as recombination centres, on the other.

The macroscopic volume changes of selected polymers subjected to uniform tensile deformation

AbstractHigh density polyethylene (PE), polycarbonate (PC), and polymethylmethacrylate (PMMA) were subjected to uniaxial tensile deformation up to the onset of instability or necking. Simultaneous readings of longitudinal extension and transverse contraction (width and thickness) were obtained continuously during the loading period. From these data, plots of longitudinal versus “average” transverse strain were produced and it was found that the trends were neither constant nor linear over the full strain range employed. Additional plots of per cent volume change versus longitudinal strain indicate that the PMMA and PC show a maximum volume increase of about 0.6% while PE shows a maximum volume decrease on the order of 2.5%. Similar volume decreases have been noted by others and it would appear that structural changes are the most likely cause of this behavior.

Burnup and temperature dependence of swelling in U3Si

The initial swelling in irradiated U 3Si fuel elements is dependent on burnup and temperature. The volume increase, ΔV/ V, was determined as a function of fuel radius in elements which operated at calculated central temperatures between 530 and 600 °C, and surface temperatures from 350 to 380 °C. Fuel burnups varied from 50 to 990 MWd/tonne U. There was no significant swelling up to at least 270 MWd/ tonne U, with the first such indication occurring at 795 MWd/tonne U, where the peak ΔV/ V value was 8%. At 990 MWd/tonne U, the maximum volume increase was 11.5%. At both burnups the swelling was temperature dependent, with the maxima in the range from 500 to 540 °C. Transmission electron microscopy of low burnup samples revealed defects which may represent an early stage in the growth of pores responsible for the swelling observed at higher burnups. Previous studies in the range 1500–8400 MWd/ tonne U have been extended to 14 700 MWd/tonne U; no further volume increase occurred with the additional burnup.