Sample records for orbital wall fracture

  1. Transcaruncular Approach for Treatment of Medial Wall and Large Orbital Blowout Fractures.

    PubMed

    Nguyen, Dennis C; Shahzad, Farooq; Snyder-Warwick, Alison; Patel, Kamlesh B; Woo, Albert S

    2016-03-01

    We evaluate the safety and efficacy of the transcaruncular approach for reconstruction of medial orbital wall fractures and the combined transcaruncular-transconjunctival approach for reconstruction of large orbital defects involving the medial wall and floor. A retrospective review of the clinical and radiographic data of patients who underwent either a transcaruncular or a combined transcaruncular-transconjunctival approach by a single surgeon for orbital fractures between June 2007 and June 2013 was undertaken. Seven patients with isolated medial wall fractures underwent a transcaruncular approach, and nine patients with combined medial wall and floor fractures underwent a transcaruncular-transconjunctival approach with a lateral canthotomy. Reconstruction was performed using a porous polyethylene implant. All patients with isolated medial wall fractures presented with enophthalmos. In the combined medial wall and floor group, five out of eight patients had enophthalmos with two also demonstrating hypoglobus. The size of the medial wall defect on preoperative computed tomography (CT) scan ranged from 2.6 to 4.6 cm(2); the defect size of combined medial wall and floor fractures was 4.5 to 12.7 cm(2). Of the 11 patients in whom postoperative CT scans were obtained, all were noted to have acceptable placement of the implant. All patients had correction of enophthalmos and hypoglobus. One complication was noted, with a retrobulbar hematoma having developed 2 days postoperatively. The transcaruncular approach is a safe and effective method for reconstruction of medial orbital floor fractures. Even large fractures involving the orbital medial wall and floor can be adequately exposed and reconstructed with a combined transcaruncular-transconjunctival-lateral canthotomy approach. The level of evidence of this study is IV (case series with pre/posttest).

  2. Real Time Navigation-Assisted Orbital Wall Reconstruction in Blowout Fractures.

    PubMed

    Shin, Ho Seong; Kim, Se Young; Cha, Han Gyu; Han, Ba Leun; Nam, Seung Min

    2016-03-01

    Limitation in performing restoration of orbital structures is the narrow, deep, and dark surgical field, which makes it difficult to view the operative site directly. To avoid perioperative complications from this limitation, the authors have evaluated the usefulness of computer-assisted navigation techniques in surgical treatment of blowout fracture. Total 37 patients (14 medial orbital wall fractures and 23 inferior orbital wall fractures) with facial deformities had surgical treatment under the guide of navigation system between September 2012 and January 2015. All 37 patients were treated successfully and safely with navigation-assisted surgery without any complications, including diplopia, retrobulbar hematoma, globe injury, implant migration, and blindness. Blowout fracture can be treated safely under guidance of a surgical navigation system. In orbital surgery, navigation-assisted technology could give rise to improvements in the functional and aesthetic outcome and checking the position of the instruments on the surgical site in real time, without injuring important anatomic structures.

  3. Preforming of polydioxanone sheets for orbital wall fractures - A technical note.

    PubMed

    Kruber, Daniel; Hierl, Thomas; Doerfler, Hans-Martin; Huempfner-Hierl, Heike; Krause, Matthias

    2018-07-01

    Polydioxanone (PDS) sheets are commonly used in the treatment of orbital wall fractures. A potential drawback of PDS is that it may be difficult to adapt to the anatomy of the orbital walls. Therefore a study was conceived to test the feasibility of preforming PDS sheets. PDS sheet material was water-heated and preformed using a template based on a statistical anatomical model. Then the deformed sheet was cooled, stored and compared to the original model to investigate post-deformation changes. PDS sheet material could easily be deformed using a mould. No significant post-cooling shape changes were noticed. PDS sheet material can be preformed into complex geometric shapes. This could be a benefit in the treatment of orbital wall fractures. Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  4. Safety of silastic sheet for orbital wall reconstruction.

    PubMed

    Moon, Seong June; Suh, Hyun Suk; Park, Bo Young; Kang, So Ra

    2014-07-01

    Many implants are being used for the reconstruction of orbital wall fractures. The effect of the choice of implant for the reconstruction of an orbital wall fracture on the surgical outcome is under debate. The purpose of this article is to compare the outcomes of orbital wall reconstruction of small orbital wall fractures on the basis of the implants used. The authors conducted a retrospective study using electronic databases. Between March 2001 and December 2012, 461 patients with orbital wall fractures were included in this study. Among them, 431 patients in whom the fracture size was less than 300 mm(2) were analyzed. The fracture size was calculated using computed tomography scans of the orbit in the sagittal and coronal images. Cases in which the fracture size was less than 300 mm(2) were included in this study. One hundred and twenty-nine patients were treated with silastic sheets; 238 patients were treated with titanium meshes; and absorbable meshes were used in the case of 64 patients. Overall, 13 patients required revision, and the revision rate was 3.0%. The revision rate of the silastic sheet group was 5.4%. In the multivariable analysis, the revision rate of the group reconstructed with silastic sheets was highly statistically significant (P=0.043, odds ratio=3.65). However, other factors such as age, sex, fracture type, and fracture size were not significant. Reconstruction of orbital wall fractures with silastic sheets may cause more complications than that with other materials such as titanium meshes and absorbable meshes.

  5. Orbital blowout fracture location in Japanese and Chinese patients.

    PubMed

    Sun, Michelle T; Wu, Wencan; Watanabe, Akihide; Kakizaki, Hirohiko; Chen, Ben; Ueda, Kosuke; Katori, Nobutada; Takahashi, Yasuhiro; Selva, Dinesh

    2015-01-01

    To characterize the location of orbital blowout fractures in Asian individuals. This was a retrospective review of 470 consecutive Asian patients with orbital blowout fractures who presented to four tertiary care hospitals in Japan and China. Computed tomography (CT) characterized the location and severity of fractures involving the medial wall, the orbital floor, and/or the maxilloethmoidal strut. A total of 475 orbital blowout fractures were identified. More than one fracture location was involved in 19% of all cases. The medial orbital wall was the most commonly involved location, presenting in 29 cases (61%), of which 204 (43%) were isolated medial blowout fractures. The orbital floor was the second most common location involved, present in 226 cases (48%) with 150 isolated orbital floor fractures (32%), while the maxilloethmoidal strut was involved in 45 cases (9%) with 30 of those being isolated strut fractures (6%). The majority of fractures (62%) were classified as moderately severe, whilst 14% were mild, and 24% were severe. Associated nasal fractures were present in 16% of the cases. Orbital blowout fractures in Japanese and Chinese individuals occur most commonly in the medial wall. This is in contrast to previous reports on white individuals, who tend to sustain fractures involving the orbital floor rather than the medial wall.

  6. The use of cone beam computed tomography in the postoperative assessment of orbital wall fracture reconstruction.

    PubMed

    Tsao, Kim; Cheng, Andrew; Goss, Alastair; Donovan, David

    2014-07-01

    Computed tomography (CT) is currently the standard in postoperative evaluation of orbital wall fracture reconstruction, but cone beam computed tomography (CBCT) offers potential advantages including reduced radiation dose and cost. The purpose of this study is to examine objectively the image quality of CBCT in the postoperative evaluation of orbital fracture reconstruction, its radiation dose, and cost compared with CT. Four consecutive patients with orbital wall fractures in whom surgery was indicated underwent orbital reconstruction with radio-opaque grafts (bone, titanium-reinforced polyethylene, and titanium plate) and were assessed postoperatively with orbital CBCT. CBCT was evaluated for its ability to provide objective information regarding the adequacy of orbital reconstruction, radiation dose, and cost. In all patients, CBCT was feasible and provided hard tissue image quality comparable to CT with significantly reduced radiation dose and cost. However, it has poorer soft tissue resolution, which limits its ability to identify the extraocular muscles, their relationship to the reconstructive graft, and potential muscle entrapment. CBCT is a viable alternative to CT in the routine postoperative evaluation of orbital fracture reconstruction. However, in the patient who develops gaze restriction postoperatively, conventional CT is preferred over CBCT for its superior soft tissue resolution to exclude extraocular muscle entrapment.

  7. Application of Rapid Prototyping Technique and Intraoperative Navigation System for the Repair and Reconstruction of Orbital Wall Fractures

    PubMed Central

    Cha, Jong Hyun; Lee, Yong Hae; Ruy, Wan Chul; Roe, Young; Moon, Myung Ho

    2016-01-01

    Background Restoring the orbital cavity in large blow out fractures is a challenge for surgeons due to the anatomical complexity. This study evaluated the clinical outcomes and orbital volume after orbital wall fracture repair using a rapid prototyping (RP) technique and intraoperative navigation system. Methods This prospective study was conducted on the medical records and radiology records of 12 patients who had undergone a unilateral blow out fracture reconstruction using a RP technique and an intraoperative navigation system from November 2014 to March 2015. The surgical results were assessed by an ophthalmic examination and a comparison of the preoperative and postoperative orbital volume ratio (OVR) values. Results All patients had a successful treatment outcome without complications. Volumetric analysis revealed a significant decrease in the mean OVR from 1.0952±0.0662 (ranging from 0.9917 to 1.2509) preoperatively to 0.9942±0.0427 (ranging from 0.9394 to 1.0680) postoperatively. Conclusion The application of a RP technique for the repair of orbital wall fractures is a useful tool that may help improve the clinical outcomes by understanding the individual anatomy, determining the operability, and restoring the orbital cavity volume through optimal implant positioning along with an intraoperative navigation system. PMID:28913272

  8. Medial orbital wall reconstruction with flexible Ethisorb patches.

    PubMed

    Pohlenz, P; Adler, W; Li, L; Schmelzle, R; Klatt, J

    2013-03-01

    The aim of this study was to analyse the long-term result after reconstruction of the medial orbital wall with a flexible, biodegradable material (Ethisorb). During a period of almost 8 years, 31 patients with a medial orbital wall fracture were analysed retrospectively. Inclusion criteria were patients with a maximum size fracture of the orbital medial wall measuring 1.5-2 cm(2). Exophthalmos, enophthalmos, bulbus motility, diplopia and skin sensation were investigated over a period of 6 months. In all patients, the medial orbital wall was reconstructed with Ethisorb patches. No significant intraoperative complications were detected. No postoperative infection, abscess or seroma was found in any of the patients receiving an Ethisorb patch. The advantage of the semiflexibility of the Ethisorb patch is that it supplies an anatomically correct fit to the orbital medial wall but does not require fixation by screws or the use of sutures. The low rate of reported bulbus motility disturbance, diplopia, exophthalmos and enophthalmos demonstrates acceptable results after medial orbital wall reconstruction using the Ethisorb patch.

  9. Endoscopic transnasal approach for the treatment of isolated medial orbital blow-out fractures: a prospective study of preoperative and postoperative orbital volume change.

    PubMed

    Kim, KyoungHoon; Song, KyeongHo; Choi, SooJong; Bae, YongChan; Choi, ChiWon; Oh, HeungChan; Lee, JaeWoo; Nam, SuBong

    2012-02-01

    Endoscopic transnasal reduction is a safe and effective technique for the treatment of blow-out fractures of the medial orbital wall. However, because this approach does not use rigid permanent material for reconstruction of the fractured medial orbital wall, some degree of herniation of the orbital contents may occur after the intraethmoidal packing material is removed. The purpose of this study was to evaluate the change in orbital volume in patients with medial orbital wall fractures treated through an endoscopic transnasal approach. This study was a prospective analysis that includes 20 patients who underwent endoscopic transnasal reduction of medial orbital wall fractures between April 2007 and December 2008. Computer-assisted orbital volume measurements were made using axial computed tomography. The mean (standard deviation [SD]) volume increase was 2.00 (0.92) cm(3) and the mean (SD) dimension of the fractured orbital wall was 2.76 (0.83) cm(2). After endoscopic surgery, an average (SD) volume decrease of 2.15 (0.91) cm(3) was achieved with ethmoid sinus packing. After removal of the packing materials, 1.14 (0.78) cm(3) increase of the orbital volume was observed. The dimension of the orbital wall fracture significantly correlated with the increased preoperative orbital volume (P = 0.002, r = 0.609); the preoperative increase in the orbital volume also significantly correlated with volume relapse after removal of the packing (P = 0.023, r = 0.452). These findings suggest that in broad orbital wall fractures, reconstruction of the orbital wall by rigid materials or prolongation of the packing period should be considered, because orbital volume can increase again after packing removal, and may thus lead to postoperative complications.

  10. Similarity in Bilateral Isolated Internal Orbital Fractures.

    PubMed

    Chen, Hung-Chang; Cox, Jacob T; Sanyal, Abanti; Mahoney, Nicholas R

    2018-04-13

    In evaluating patients sustaining bilateral isolated internal orbital fractures, the authors have observed both similar fracture locations and also similar expansion of orbital volumes. In this study, we aim to investigate if there is a propensity for the 2 orbits to fracture in symmetrically similar patterns when sustaining similar trauma. A retrospective chart review was performed studying all cases at our institution of bilateral isolated internal orbital fractures involving the medial wall and/or the floor at the time of presentation. The similarity of the bilateral fracture locations was evaluated using the Fisher's exact test. The bilateral expanded orbital volumes were analyzed using the Wilcoxon signed-rank test to assess for orbital volume similarity. Twenty-four patients with bilateral internal orbital fractures were analyzed for fracture location similarity. Seventeen patients (70.8%) had 100% concordance in the orbital subregion fractured, and the association between the right and the left orbital fracture subregion locations was statistically significant (P < 0.0001). Fifteen patients were analyzed for orbital volume similarity. The average orbital cavity volume was 31.2 ± 3.8 cm on the right and 32.0 ± 3.7 cm on the left. There was a statistically significant difference between right and left orbital cavity volumes (P = 0.0026). The data from this study suggest that an individual who suffers isolated bilateral internal orbital fractures has a statistically significant similarity in the location of their orbital fractures. However, there does not appear to be statistically significant similarity in the expansion of the orbital volumes in these patients.

  11. Patient-specific puzzle implant preformed with 3D-printed rapid prototype model for combined orbital floor and medial wall fracture.

    PubMed

    Kim, Young Chul; Min, Kyung Hyun; Choi, Jong Woo; Koh, Kyung S; Oh, Tae Suk; Jeong, Woo Shik

    2018-04-01

    The management of combined orbital floor and medial wall fractures involving the inferomedial strut is challenging due to absence of stable cornerstone. In this article, we proposed surgical strategies using customized 3D puzzle implant preformed with Rapid Prototype (RP) skull model. Retrospective review was done in 28 patients diagnosed with combined orbital floor and medial wall fracture. Using preoperative CT scans, original and mirror-imaged RP skull models for each patient were prepared and sterilized. In all patients, porous polyethylene-coated titanium mesh was premolded onto RP skull model in two ways; Customized 3D jigsaw puzzle technique was used in 15 patients with comminuted inferomedial strut, whereas individual 3D implant technique was used in each fracture for 13 patients with intact inferomedial strut. Outcomes including enophthalmos, visual acuity, and presence of diplopia were assessed and orbital volume was measured using OsiriX software preoperatively and postoperatively. Satisfactory results were achieved in both groups in terms of clinical improvements. Of 10 patients with preoperative diplopia, 9 improved in 6 months, except one with persistent symptom who underwent extraocular muscle rupture. 18 patients who had moderate to severe enophthalmos preoperatively improved, and one remained with mild degree. Orbital volume ratio, defined as volumetric ratio between affected and control orbit, decreased from 127.6% to 99.79% (p < 0.05) in comminuted group, and that in intact group decreased from 117.03% to 101.3% (p < 0.05). Our surgical strategies using the jigsaw puzzle and individual reconstruction technique provide accurate restoration of combined orbital floor and medial wall fractures. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  12. Acquired simulated brown syndrome following surgical repair of medial orbital wall fracture.

    PubMed

    Hwang, Jong-uk; Lim, Hyun Taek

    2005-03-01

    Simulated Brown syndrome is a term applied to a myriad of disorders that cause a Brown syndrome-like motility. We encountered a case of acquired simulated Brown syndrome in a 41-year-old man following surgical repair of fractures of both medial orbital walls. He suffered from diplopia in primary gaze, associated with hypotropia of the affected eye. We performed an ipsilateral recession of the left inferior rectus muscle as a single-stage intraoperative adjustment procedure under topical anesthesia, rather than the direct approach to the superior oblique tendon. Postoperatively, the patient was asymptomatic in all diagnostic gaze positions.

  13. A study of sports-related orbital fractures in Singapore.

    PubMed

    Lock, Jing Zhan; Hegde, Raghuraj; Young, Stephanie; Lim, Thiam Chye; Amrith, Shantha; Sundar, Gangadhara

    2017-10-01

    With an increased popularity of sport and active living worldwide, our study aims to explore the incidence and features of sports-related orbital fractures in Singapore. 1421 computer tomography (CT) imaging scans of the face and orbits done at the National University Hospital over a 24-month period from January 2013 and December 2014 were reviewed retrospectively for orbital fractures. We identified 483 orbital fractures of which sports injury was the fourth most common etiology (n = 65; 13.5%) after road traffic accident (n = 131; 27.1%), geriatric fall (n = 81; 16.8%) and workplace injury (n = 67; 13.9%). The three most common sport in orbital fractures were soccer (n = 20; 30.8%), bicycling (n = 11; 16.9%) and jogging (n = 8; 12.3%). The three most common fracture patterns were zygomatico-maxillary complex fractures (n = 24; 36.9%), isolated one wall blowout fractures (n = 19; 29.2%) and naso-orbito-ethmoid fractures (n = 7; 10.8%). Sports-related orbital fractures were associated with a low mean age of patients (45.9 years, range, 14-79 years), a higher proportion of males (n = 58; 89.2%) than that from geriatric falls (n = 37, 45.6%) (P < 0.01), a higher likelihood of unilaterality (n = 62; 95.4%) than that from traffic accidents (n = 99; 75.6%) (P < 0.01) and a lower likelihood of pan-facial involvement (n = 4; 6.15%) than that from traffic accident (n = 60; 45.8%) (P < 0.01). Sports-related orbital fractures are the fourth most common cause of orbital fractures. Though commonly seen in young male adults, in view of the aging population and people exercising more regularly, education of safety measures among sports users is paramount to preventing sports-related orbital fractures.

  14. Orbital cellulitis: a rare complication after orbital blowout fracture.

    PubMed

    Ben Simon, Guy J; Bush, Steven; Selva, Dinesh; McNab, Alan A

    2005-11-01

    To report the incidence of orbital cellulitis after orbital blowout fracture. Retrospective, noncomparative, interventional case series. All patients with orbital cellulitis and a history of recent orbital fracture. A medical record review of clinical history, imaging studies, and surgical and treatment outcome was performed. Resolution of orbital cellulitis and surgical and imaging findings. Four patients (3 male; mean age, 30 years [range, 4.5-58]) were treated for orbital cellulitis complicating orbital fracture. All patients had evidence of paranasal sinusitis before or after the orbital injury, and 2 also reported forceful nose blowing after sustaining orbital trauma. Although 3 patients received prophylactic oral antibiotics after the fracture, this failed to prevent infection. Sinusitis commenced 1 to 2 weeks before and as late as 5 weeks after orbital injury. All patients were treated with IV antibiotics. Two developed an orbital abscess that required surgical drainage; 1 patient improved after an endonasal maxillary antrostomy. One patient improved on IV antibiotics alone and underwent fracture repair at a later stage. These 4 patients represent 0.8% of all cases of orbital fractures treated in the study period. Orbital cellulitis is a rare complication of orbital fracture, and seems to be more common when paranasal sinus infection preexists or occurs within several weeks of the injury. Oral antibiotics given after the orbital injury may not prevent orbital cellulitis or abscess formation. Surgery may be required to drain orbital abscess or in nonresolving cellulitis to drain the paranasal sinuses. Fracture repair, if indicated, should be delayed, particularly if an alloplastic implant is used.

  15. Incidence of intracranial injury in orbital wall fracture patients not classified as traumatic brain injury.

    PubMed

    Lee, Hyung-Joo; Kim, Youn-Jung; Seo, Dong-Woo; Sohn, Chang Hwan; Ryoo, Seung Mok; Ahn, Shin; Lee, Yoon-Seon; Kim, Won Young; Lim, Kyoung Soo

    2018-05-01

    The detection of intracranial injury in patients with facial injury rather than traumatic brain injury (TBI) remains a challenge for emergency physicians. This study aimed to evaluate the incidence and risk factors of intracranial injury in patients with orbital wall fracture (OWF), who were classified with a chief complaint of facial injury rather than TBI. This retrospective case-control study enrolled adult OWF patients (age ≥18 years) who presented at the hospital between January 2004 and March 2016. Patients with definite TBI were excluded because non-contrast head computed tomography (CT) is recommended for such patients. A total of 1220 patients with OWF were finally enrolled. CT of the head was performed on 677 patients, and the incidence of concomitant intracranial injury was found to be 9% (62/677). Patients with definite TBI were excluded. Symptoms raising a suspicion of TBI, such as loss of consciousness, alcohol intoxication, or vomiting, were present in 347 of the patients, with 44 of these patients (13%) showing a concomitant intracranial injury. Of the 330 patients without such symptoms, 18 (6%) demonstrated a concomitant intracranial injury. In OWF patients, superior wall fracture (odds ratio [OR], 4.15; 95% confidence interval [CI], 2.06-8.34; P < 0.001), associated frontal bone fracture (OR, 4.38; 95% CI, 2.08-9.23; P < 0.001), and older age (decades) (OR, 1.03; 95% CI, 1.01-1.04; P = 0.002) were independent risk factors for concomitant intracranial injury. Emergency physicians should maintain a high degree of suspicion of TBI, even when their primary concern is facial trauma with OWF. Head CT is recommended for OWF patients with a superior OWF, frontal bone fracture, or increased age. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. In Situ Splitting of a Rib Bone Graft for Reconstruction of Orbital Floor and Medial Wall.

    PubMed

    Uemura, Tetsuji; Yanai, Tetsu; Yasuta, Masato; Harada, Yoshimi; Morikawa, Aya; Watanabe, Hidetaka; Kurokawa, Masato

    2017-06-01

    In situ splitting of rib bone graft was conducted in 22 patients for the repair of orbital fracture with no other complicating fractures. A bone graft was harvested from the sixth or seventh rib in the right side. The repair of the orbital floor and medial wall was successful in all the cases. Ten patients had bone grafting to the orbital floor, eight had it done onto medial wall, and 4 onto both floor and wall after reduction. The mean length of in situ rib bone graft was 40.9 mm (range, 20-70 mm), the mean width of these was 14.9 mm (range, 8-20 mm). The bone grafting was done by one leaf for 15 cases and two leafs for 7 cases in size of defects. The technique of in situ splitting of a rib bone graft for the repair of the orbital floor and medial wall is a simple and safe procedure, easily taking out the in situ splitting of a rib, and less pain in donor site. It has proved to be an optimal choice in craniofacial reconstruction, especially the defects of orbital floor and medial wall.

  17. Combined Orbital Fractures: Surgical Strategy of Sequential Repair

    PubMed Central

    Hur, Su Won; Kim, Sung Eun; Chung, Kyu Jin; Lee, Jun Ho; Kim, Tae Gon

    2015-01-01

    Background Reconstruction of combined orbital floor and medial wall fractures with a comminuted inferomedial strut (IMS) is challenging and requires careful practice. We present our surgical strategy and postoperative outcomes. Methods We divided 74 patients who underwent the reconstruction of the orbital floor and medial wall concomitantly into a comminuted IMS group (41 patients) and non-comminuted IMS group (33 patients). In the comminuted IMS group, we first reconstructed the floor stably and then the medial wall by using separate implant pieces. In the non-comminuted IMS group, we reconstructed the floor and the medial wall with a single large implant. Results In the follow-up of 6 to 65 months, most patients with diplopia improved in the first-week except one, who eventually improved at 1 year. All patients with an EOM limitation improved during the first month of follow-up. Enophthalmos (displacement, 2 mm) was observed in two patients. The orbit volume measured on the CT scans was statistically significantly restored in both groups. No complications related to the surgery were observed. Conclusions We recommend the reconstruction of orbit walls in the comminuted IMS group by using the following surgical strategy: usage of multiple pieces of rigid implants instead of one large implant, sequential repair first of the floor and then of the medial wall, and a focus on the reconstruction of key areas. Our strategy of step-by-step reconstruction has the benefits of easy repair, less surgical trauma, and minimal stress to the surgeon. PMID:26217562

  18. Orbital Floor Fracture with Atypical Extraocular Muscle Entrapment Pattern and Intraoperative Asystole in an Adult

    PubMed Central

    Merali, Farhan I.; Grant, Michael P.; Mahoney, Nicholas R.

    2015-01-01

    Extraocular muscle entrapment in a nondisplaced orbital fracture, although a well-known entity in pediatric trauma, is atypical in adults. It can present with a triad of bradycardia, nausea, and in rare cases, syncope, and result in severe fibrosis of damaged and incarcerated muscle. We present a case of muscle entrapment in a partially nondisplaced two-wall orbital fracture with accompanying preoperative bradycardia and intraoperative asystole in an adult PMID:26576246

  19. Pediatric Orbital Fractures

    PubMed Central

    Oppenheimer, Adam J.; Monson, Laura A.; Buchman, Steven R.

    2013-01-01

    It is wise to recall the dictum “children are not small adults” when managing pediatric orbital fractures. In a child, the craniofacial skeleton undergoes significant changes in size, shape, and proportion as it grows into maturity. Accordingly, the craniomaxillofacial surgeon must select an appropriate treatment strategy that considers both the nature of the injury and the child's stage of growth. The following review will discuss the management of pediatric orbital fractures, with an emphasis on clinically oriented anatomy and development. PMID:24436730

  20. Traumatic globe luxation associated with orbital fracture in a child: a case report and literature review.

    PubMed

    Amaral, Márcio Bruno Figueiredo; Carvalho, Matheus Furtado; Ferreira, André Baptista; Mesquita, Ricardo Alves

    2015-03-01

    Orbital fracture associated with traumatic globe luxation is rare, as it generally requires trauma with high energy for this to occur. The present case report focused on a child who had been hit by a motorcycle, leading to a globe luxation of the left eye and fractures of the superolateral orbital walls. The patient presented initial cosmetic and psychological benefits from the repositioning of the intact globe and the reduction of the orbital fractures. However, a subsequent evisceration of the globe was required due to persistent proptosis and pain. An ocular prosthesis was also implanted, thus recovering the patient's aesthetics. Thirty-four well-documented cases of traumatic globe luxation could be found in the English literature since 1970. The mean age of patients presenting traumatic globe luxation was 29.5 years. The male gender proved to be more prevalent, with traffic collisions representing the most common accident etiology. Direct orbital trauma with fractures of medial and floor walls displacing the globe into the maxillary sinus represented the most common injury mechanism (38.2 %), followed by an elongated object entering the orbit (26.5 %). Optical nerve avulsion is the most serious complication seen in association with traumatic globe luxation, with the repositioning of the initial globe, with no enucleation or evisceration, representing the main form of management.

  1. Orbital fractures due to domestic violence: an epidemiologic study.

    PubMed

    Goldberg, Stuart H.; McRill, Connie M.; Bruno, Christopher R.; Ten Have, Tom; Lehman, Erik

    2000-09-01

    Domestic violence is an important cause of orbital fractures in women. Physicians who treat patients with orbital fractures may not suspect this mechanism of injury. The purpose of this study was to assess the association between domestic violence and orbital fractures. A medical center-based case-control study with matching on age and site of admission was done. Medical center databases were searched using ICD-9 codes to identify all cases of orbital fractures encountered during a three-year period. Medical records of female patients age 13 and older were reviewed along with those of age, gender and site of admission matched controls. A stratified exact test was employed to test the association between domestic violence and orbital fracture. Among 41 adult female cases with orbital fractures treated at our medical center, three (7.3%) reported domestic violence compared to zero among the matched controls (p = 0.037). We believe that domestic violence may be under-reported in both orbital fracture cases and controls. This may result in an underestimate of the orbital fracture versus domestic violence association. Domestic violence is a serious women's health and societal problem. Domestic violence may have a variety of presentations, including illnesses and injuries. Orbital fracture is an identifiable manifestation of domestic violence. Domestic violence is more likely to be detected in adult female hospital patients with orbital fracture than in matched controls with any other diagnosis. Physicians who treat patients with orbital fractures should be familiar with this mechanism of injury.

  2. Orbital fracture and eyeball rupture caused by golf-club injury.

    PubMed

    Hwang, Kun; Kim, Joo Ho

    2014-05-01

    We report a case of an orbital fracture and an eyeball rupture caused by a golf-club injury. A 75-year-old man was struck in his right eye by a golf club while watching behind his son swinging a hybrid-type golf club at his home. A 70-mm muscle-depth laceration was present in the infraorbital area with active bleeding. Computed tomographic imaging of the face revealed a rupture of the right eyeball; fractures in the superior, medial, lateral, and inferior wall of the right orbit; a fracture in the right zygomaticofrontal junction; and a small amount of pneumocephalus in the parafalx region. Under general anesthesia, evisceration of the right eyeball was performed. Not only golfers but also people just watching or passing by can be injured by an errantly struck golf ball or swung golf club. Elderly people as well as children should be instructed in technique and safety and also be supervised when playing golf. Also, the public should be educated about the risk of eye injuries and the benefits of wearing a protective eyewear.

  3. Alloplastic implants for orbital wall reconstruction.

    PubMed

    Jacono, A A; Moskowitz, B

    2000-01-01

    Nonabsorbable alloplastic implants for orbital wall reconstruction have been widely accepted by surgeons because of their ready availability, stability, and biocompatability. Many complications have arisen with this class of implants because the lack of host tissue integration allows for implant migration, implant extrusion, recurrent hemorrhage, and infection. Porous polyethylene implants provide a welcome alternative as they have the unique properly of supporting tissue ingrowth in vivo. Their semirigid structure provides structural stability when used around the orbit, and their malleability allows for easy contouring. This paper presents our surgical approach to reconstructing orbital defects with porous polyethylene implants, including orbital floor, and superior, medial, and lateral wall defects, and discusses the advantages/disadvantages of other nonabsorbable alloplasts.

  4. Bifurcating Particle Swarms in Smooth-Walled Fractures

    NASA Astrophysics Data System (ADS)

    Pyrak-Nolte, L. J.; Sun, H.

    2010-12-01

    Particle swarms can occur naturally or from industrial processes where small liquid drops containing thousands to millions of micron-size to colloidal-size particles are released over time from seepage or leaks into fractured rock. The behavior of these particle swarms as they fall under gravity are affected by particle interactions as well as interactions with the walls of the fractures. In this paper, we present experimental results on the effect of fractures on the cohesiveness of the swarm and the formation of bifurcation structures as they fall under gravity and interact with the fracture walls. A transparent cubic sample (100 mm x 100 mm x 100 mm) containing a synthetic fracture with uniform aperture distributions was optically imaged to quantify the effect of confinement within fractures on particle swarm formation, swarm velocity, and swarm geometry. A fracture with a uniform aperture distribution was fabricated from two polished rectangular prisms of acrylic. A series of experiments were performed to determine how swarm movement and geometry are affected as the walls of the fracture are brought closer together from 50 mm to 1 mm. During the experiments, the fracture was fully saturated with water. We created the swarms using two different particle sizes in dilute suspension (~ 1.0% by mass). The particles were 3 micron diameter fluorescent polymer beads and 25 micron diameter soda-lime glass beads. Experiments were performed using swarms that ranged in size from 5 µl to 60 µl. The swarm behavior was imaged using an optical fluorescent imaging system composed of a CCD camera illuminated by a 100 mW diode-pumped doubled YAG laser. As a swarm falls in an open-tank of water, it forms a torroidal shape that is stable as long as no ambient or background currents exist in the water tank. When a swarm is released into a fracture with an aperture less than 5 mm, the swarm forms the torroidal shape but it is distorted because of the presence of the walls. The

  5. Status of the internal orbit after reduction of zygomaticomaxillary complex fractures.

    PubMed

    Ellis, Edward; Reddy, Likith

    2004-03-01

    We sought to determine the status of the internal orbit before and after reduction of zygomaticomaxillary complex (ZMC) fractures when treated without internal orbital reconstruction. We conducted a retrospective study of preoperative and postoperative computed tomography (CT) scans in 65 patients with unilateral ZMC fractures who were treated by reduction of the ZMC complex without internal orbital reconstruction. The size and location of the internal orbital defects, orbital soft tissue displacement, and orbital volume were assessed in the preoperative and postoperative CT scans. Reduction in the ZMC fractures was considered ideal in 58 of the 65 patients. Only minor malpositions occurred in the remaining 7 patients. The size of the internal orbital defects increased slightly with ZMC reduction but the internal orbital fractures were realigned, and few had increases in orbital volume or soft tissue sagging into the sinuses. Examination of follow-up CT scans in several patients taken weeks to months later showed that the residual defects became smaller and that none of these patients had an increase in orbital volume or soft tissue sagging. The preoperative CT scan can be used to assess the amount of internal orbital disruption for purposes of developing a treatment plan in patients with ZMC fractures. When there is minimal or no soft tissue herniation and minimal disruption of the internal orbit, ZMC reduction is adequate treatment.

  6. [One case report: removal of foreign body in ethmoidal sinus-medial orbital wall through nose assisted by endoscope].

    PubMed

    Yang, Zeyin; Yang, Xiaohong

    2013-07-01

    The patient was male, 20 years old, and complained of pain, bleeding and decreased vision after the right eye was injured by nail for an hour. right exophthalmos, conjunctival edema, skin laceration at the lower eyelid of right eye, limitation of eye movement, asymmetric eyes and weak light-reflecting. X-ray showed: metallic foreign body shadow in the right orbit, 0.5 cm x 0.4 cm approximately. Orbit and paranasal sinus CT showed: 1 hematoma of the right eye and inside. 2 high density foreign body embedded in the bone wall of the inside of right orbit and ethmoid. 3 medial wall fracture of right eye orbit. 4 bilateral maxillary sinus and right ethmoidal sinus effusion. 5 slightly left side of nasal septum. The patient was initially diagnosed as foreign body in right ethmoidal sinus, skin laceration of right lower eyelid, retrobulbar hematoma.

  7. Interaction of hydraulic and buckling mechanisms in blowout fractures.

    PubMed

    Nagasao, Tomohisa; Miyamoto, Junpei; Jiang, Hua; Tamaki, Tamotsu; Kaneko, Tsuyoshi

    2010-04-01

    The etiology of blowout fractures is generally attributed to 2 mechanisms--increase in the pressure of the orbital contents (the hydraulic mechanism) and direct transmission of impacts on the orbital walls (the buckling mechanism). The present study aims to elucidate whether or not an interaction exists between these 2 mechanisms. We performed a simulation experiment using 10 Computer-Aided-Design skull models. We applied destructive energy to the orbits of the 10 models in 3 different ways. First, to simulate pure hydraulic mechanism, energy was applied solely on the internal walls of the orbit. Second, to simulate pure buckling mechanism, energy was applied solely on the inferior rim of the orbit. Third, to simulate the combined effect of the hydraulic and buckling mechanisms, energy was applied both on the internal wall of the orbit and inferior rim of the orbit. After applying the energy, we calculated the areas of the regions where fracture occurred in the models. Thereafter, we compared the areas among the 3 energy application patterns. When the hydraulic and buckling mechanisms work simultaneously, fracture occurs on wider areas of the orbital walls than when each of these mechanisms works separately. The hydraulic and buckling mechanisms interact, enhancing each other's effect. This information should be taken into consideration when we examine patients in whom blowout fracture is suspected.

  8. Intraoperative CT in the assessment of posterior wall acetabular fracture stability.

    PubMed

    Cunningham, Brian; Jackson, Kelly; Ortega, Gil

    2014-04-01

    Posterior wall acetabular fractures that involve 10% to 40% of the posterior wall may or may not require an open reduction and internal fixation. Dynamic stress examination of the acetabular fracture under fluoroscopy has been used as an intraoperative method to assess joint stability. The aim of this study was to demonstrate the value of intraoperative ISO computed tomography (CT) examination using the Siemens ISO-C imaging system (Siemens Corp, Malvern, Pennsylvania) in the assessment of posterior wall acetabular fracture stability during stress examination under anesthesia. In 5 posterior wall acetabular fractures, standard fluoroscopic images (including anteroposterior pelvis and Judet radiographs) with dynamic stress examinations were compared with the ISO-C CT imaging system to assess posterior wall fracture stability during stress examination. After review of standard intraoperative fluoroscopic images under dynamic stress examination, all 5 cases appeared to demonstrate posterior wall stability; however, when the intraoperative images from the ISO-C CT imaging system demonstrated that 1 case showed fracture instability of the posterior wall segment during stress examination, open reduction and internal fixation was performed. The use of intraoperative ISO CT imaging has shown an initial improvement in the surgeon's ability to assess the intraoperative stability of posterior wall acetabular fractures during stress examination when compared with standard fluoroscopic images. Copyright 2014, SLACK Incorporated.

  9. [The use of a prolene double mesh for orbital wall reconstruction].

    PubMed

    Junceda-Moreno, J; Suárez-Suárez, E; Dos-Santos-Bernardo, V

    2005-08-01

    Patient with a recurrent carcinoma of the nasal fossae affecting the internal orbital wall. The intraorbital content was not affected. The orbital wall was reconstructed with a prolene double mesh anchored to the periosteum. Prolene mesh as a substitute of the orbital wall. Good stability and isolation of the intraorbital structures were observed. Ocular motility was completely normal after surgery without prolene mesh displacements. The prolene double mesh is a good surgical option to replace missing bone in the reconstruction of the internal orbital wall.

  10. Endoscopic Assisted Combined Transantral and Subciliary Approach in Treatment of Orbital Floor Fracture: A Case Report.

    PubMed

    Anehosur, Venkatesh; Harish, K

    2018-06-01

    Management of orbital floor fracture remains the most debated topic in maxillofacial field. There are many approaches to reconstruct orbital floor fractures and restore orbital position and function, but many have the drawback of incomplete visualization, especially of the posterior part of the orbit. Pain, diplopia and enophthalmos are the most common presenting symptoms in patients who sustained orbital blow out fracture. The main aim in treating orbital fracture is to reduce the prolapsed orbital tissue and reconstruct the floor which will improve diplopia and enophthalmos. As minimally invasive surgical techniques are gaining popularity, it is possible to reconstruct the orbital fracture defects using endoscopes. Endoscopic assisted combined transantral and subciliary technique provides better surgical access and outcome in the treatment of orbital floor fracture.

  11. Applications of 3D orbital computer-assisted surgery (CAS).

    PubMed

    Scolozzi, P

    2017-09-01

    The purpose of the present report is to describe the indications for use of 3D orbital computer-assisted surgery (CAS). We analyzed the clinical and radiological data of all patients with orbital deformities treated using intra-operative navigation and CAD/CAM techniques at the Hôpitaux Universitaires de Genève, Switzerland, between 2009 and 2016. We recorded age and gender, orbital deformity, technical and surgical procedure and postoperative complications. One hundred and three patients were included. Mean age was 39.5years (range, 5 to 84years) and 85 (87.5%) were men. Of the 103 patients, 96 had intra-operative navigation (34 for primary and 3 for secondary orbito-zygomatic fractures, 15 for Le Fort fractures, 16 for orbital floor fractures, 10 for combined orbital floor and medial wall fractures, 7 for orbital medial wall fractures, 3 for NOE (naso-orbito-ethmoidal) fractures, 2 for isolated comminuted zygomatic arch fractures, 1 for enophthalmos, 3 for TMJ ankylosis and 2 for fibrous dysplasia bone recontouring), 8 patients had CAD/CAM PEEK-PSI for correction of residual orbital bone contour following craniomaxillofacial trauma, and 1 patient had CAD/CAM surgical splints and cutting guides for correction of orbital hypertelorism. Two patient (1.9%) required revision surgery for readjustment of an orbital mesh. The 1-year follow-up examination showed stable cosmetic and dimensional results in all patients. This study demonstrated that the application of 3D orbital CAS with regards to intra-operative navigation and CAD/CAM techniques allowed for a successful outcome in the patients presented in this series. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  12. Repair of orbital floor fractures with absorbable gelatin film.

    PubMed

    Mermer, R W; Orban, R E

    1995-01-01

    Many materials have been utilized for the repair of orbital floor fractures. Absorbable gelatin film is a bioabsorbable sheeting material that is manufactured from denatured collagen. This material is appropriate for the repair of smaller orbital floor defects (5 mm or less) and trapdoor-type fractures; it is used with larger defects as an interpositional graft material between the periorbital tissues and as an orbital floor reconstruction plate or mesh. Sixteen cases consisting of both types of defects were retrospectively examined clinically and radiographically. Satisfactory results were obtained in all of these cases, including no adverse ocular signs or implant rejection, good facial form, good function, and acceptable postoperative radiography results.

  13. [Pediatric orbital emphysema caused by a compressed-air pistol shot: a case report].

    PubMed

    Navarro-Mingorance, A; Reyes-Dominguez, S B; León-León, M C

    2014-09-01

    We report the case of a 2 year-old child with orbital emphysema secondary to a compressed-air gun shot in the malar region, with no evidence of orbital wall fracture. Conservative treatment was applied, and no complications were observed. Orbital emphysema in the absence of an orbital wall fracture is a rare situation. Orbital emphysema is usually seen in facial trauma associated with damage to the adjacent paranasal sinuses or facial bones. To our knowledge there have been very few reports of orbital emphysema caused by a compressed-air injury. Copyright © 2012 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  14. Fault and fracture patterns around a strike-slip influenced salt wall

    NASA Astrophysics Data System (ADS)

    Alsop, G. I.; Weinberger, R.; Marco, S.; Levi, T.

    2018-01-01

    The trends of faults and fractures in overburden next to a salt diapir are generally considered to be either parallel to the salt margin to form concentric patterns, or at right angles to the salt contact to create an overall radial distribution around the diapir. However, these simple diapir-related patterns may become more complex if regional tectonics influences the siting and growth of a diapir. Using the Sedom salt wall in the Dead Sea Fault system as our case study, we examine the influence of regional strike-slip faulting on fracture patterns around a salt diapir. This type of influence is important in general as the distribution and orientation of fractures on all scales may influence permeability and hence control fluid and hydrocarbon flow. Fractures adjacent to the N-S trending salt wall contain fibrous gypsum veins and injected clastic dykes, attesting to high fluid pressures adjacent to the diapir. Next to the western flank of the salt wall, broad (∼1000 m) zones of upturn or 'drape folds' are associated with NW-SE striking conjugate extensional fractures within the overburden. Within 300 m of the salt contact, fracture patterns in map view display a progressive ∼30°-35° clockwise rotation with more NNW-SSE strikes immediately adjacent to the salt wall. While some extensional faults display growth geometries, indicating that they were syn-depositional and initiated prior to tilting of beds associated with drape folding, other fractures display increasing dips towards the salt, suggesting that they have formed during upturn of bedding near the diapir. These observations collectively suggest that many fractures developed to accommodate rotation of beds during drape folding. Extensional fractures in the overburden define a mean strike that is ∼45° anticlockwise (counter-clockwise) of the N-S trending salt wall, and are therefore consistent with sinistral transtension along the N-S trending Sedom Fault that underlies the salt wall. Our outcrop

  15. Mydriasis during Orbital Floor Fracture Reconstruction: A Novel Diagnostic and Treatment Algorithm

    PubMed Central

    Yeo, Matthew S.; Al-Mousa, Radwan; Sundar, Gangadhara; Lim, Thiam Chye

    2010-01-01

    Orbital floor fractures are the most commonly encountered traumatic fractures in the facial skeleton. Mydriasis that is detected during orbital floor fracture reconstruction may cause significant distress to surgeons, as it may be associated with sinister events such as visual loss. It is not an uncommon problem; previous studies have shown the incidence of mydriasis to be 2.1%. The combination of careful preoperative evaluation and planning, as well as specific intraoperative investigations when mydriasis is encountered, can be immensely valuable in allaying surgeons' anxiety during orbital floor fracture reconstruction. In this review article, the authors discuss the common causes of mydriasis and present a novel systematic approach to its diagnostic evaluation devised by our unit that has been successfully implemented since 2008. PMID:22132259

  16. Medial orbital wall landmarks in three different North American populations.

    PubMed

    Mehta, Milap P; Perry, Julian D

    2015-04-01

    We sought to measure the medial orbital wall foramina distances in two previously unstudied populations, to describe a new bony medial wall feature, and to validate the accuracy of a new coordinate measurement device within the orbit. Dried, well-preserved, complete human skulls without orbital defects were studied. Age, gender, birthplace, ethnicity, and laterality of the orbit were recorded for each skull. Supranumerary ethmoidal foramina were recorded, and the fronto-ethmoidal groove depth was measured. The distances between the anterior lacrimal crest (ALC) - anterior ethmoidal foramen (AEF), AEF - posterior ethmoidal foramen (PEF), and PEF - optic canal (OC) were measured first by surgical ruler and wire and then by the Microscribe coordinate measurement device. One hundred and forty-six orbits were studied. Fifty-seven orbits were of European or Caucasian descent, 68 orbits of African American descent, 2 orbits of West African descent, 11 orbits of Eskimo descent, and 8 orbits of unknown origin. No significant differences existed between the manual and Microscribe measurements for the ALC-AEF, AEF-PEF, and PEF-OF distances (p < 0.0001). A significant frontoethmoidal groove was observed in 27/146 (19%) orbits, in 6/57 (11%) Caucasian orbits, in 17/70 (24%) African American orbits, and in 4/11 (36%) Eskimo orbits. Supranumerary ethmoidal foramina were found in 50/146 orbits (34.2%) and in 17/27 (63%) orbits with a significant frontoethmoidal grooves. No significant differences in medial wall foramina distances exist between African American and Caucasian orbits; however, a frontoethmoidal groove occurs more commonly in African American orbits. This groove often occurs in the presence of supernumerary ethmoidal foramina. The Microscribe coordinate measurement system represents a valid tool to measure distances within the orbit.

  17. How reactive fluids alter fracture walls and affect shale-matrix accessibility

    NASA Astrophysics Data System (ADS)

    Fitts, J. P.; Deng, H.; Peters, C. A.

    2014-12-01

    Predictions of mass transfer across fracture boundaries and fluid flow in fracture networks provide fundamental inputs into risk and life cycle assessments of geologic energy technologies including oil and gas extraction, geothermal energy systems and geologic CO2 storage. However, major knowledge gaps exist due to the lack of experimental observations of how reactive fluids alter the pore structures and accessible surface area within fracture boundaries that control the mass transfer of organics, metals and salts, and influence fluid flow within the fracture. To investigate the fracture and rock matrix properties governing fracture boundary alteration, we developed a new flow-through cell that enables time-dependent 2D x-ray imaging of mineral dissolution and/or precipitation at a fracture surface. The parallel plate design provides an idealized fracture geometry to investigate the relationship between flow rate, reaction rate, and mineral spatial heterogeneity and variation. In the flow-cell, a carbonate-rich sample of Eagle Ford shale was reacted with acidified brine. The extent and rate of mineral dissolution were correlated with calcite abundance relative to less soluble silicate minerals. Three-dimensional x-ray tomography of the reacted fracture wall shows how calcite dissolution left behind a porous network of silicate minerals. And while this silicate network essentially preserved the location of the initial fracture wall, the pore network structures within the fracture boundary were dramatically altered, such that the accessible surface area of matrix components increased significantly. In a second set of experiments with a limestone specimen, however, the extent of dissolution and retreat of the fracture wall was not strictly correlated with the occurrence of calcite. Instead, the pattern and extent of dissolution suggested secondary causes such as calcite morphology, the presence of argillaceous minerals and other diagenetic features. Our experiments

  18. Titanium Mesh Reconstruction of Orbital Roof Fracture with Traumatic Encephalocele: A Case Report and Review of Literature

    PubMed Central

    Mokal, Nitin J.; Desai, Mahinoor F.

    2012-01-01

    Orbital roof fractures are rare. Traumatic encephaloceles in the orbital cavity are even rarer, with only 21 cases published to date. Orbital roof fractures are generally encountered in males between 20 and 40 years of age following automobile collision. We report a case of an orbital roof fracture with traumatic encephalocele into the left orbit. Early diagnosis and treatment are very important because the raised intraorbital pressure may irreversibly damage the optic nerve. Computed tomography with 3-D reconstruction, the imaging modality of choice, showed the displaced fracture fragment deep into the orbit. Reconstruction of the orbital roof should be performed in every case. We used an extracranial approach to elevate the fracture with titanium mesh to stabilize the fragment. The cosmetic results were excellent but delay in treatment was responsible for delayed recovery of vision. The case report is followed by a brief overview of orbital roof fractures including pertinent review of literature. PMID:23450105

  19. Single-stage soft tissue reconstruction and orbital fracture repair for complex facial injuries.

    PubMed

    Wu, Peng Sen; Matoo, Reshvin; Sun, Hong; Song, Li Yuan; Kikkawa, Don O; Lu, Wei

    2017-02-01

    Orbital fractures with open periorbital wounds cause significant morbidity. Timing of debridement with fracture repair and soft tissue reconstruction is controversial. This study focuses on the efficacy of early single-stage repair in combined bony and soft tissue injuries. Retrospective review. Twenty-three patients with combined open soft tissue wounds and orbital fractures were studied for single-stage orbital reconstruction and periorbital soft tissue repair. Inclusion criteria were open soft tissue wounds with clinical and radiographic evidence of orbital fractures and repair performed within 48 h after injury. Surgical complications and reconstructive outcomes were assessed over 6 months. The main outcome measures were enophthalmos, pre- and post-CT imaging of orbits, scar evaluation, presence of diplopia, and eyelid position. Enophthalmos was corrected in 16/19 cases and improved in 3/19 cases. 3D reconstruction of CT images showed markedly improved orbital alignment with objective measurements of the optic foramen to cornea distance (mm) in reconstructed orbits relative to intact orbits of 0.66, 95% confidence interval [CI] (lower 0.33, upper 0.99) mm. The mean baseline of Stony Brook Scar Evaluation Scale was 0.6, 95%CI (0.30-0.92), and for 6 months, the mean score was 3.4, 95%CI (3.05-3.73). Residual diplopia in secondary gazes was present in two patients; one patient had ectropion. Complications included one case of local wound infection. An early single-stage repair of combined soft tissue and orbital fractures yields satisfactory functional and aesthetic outcomes. Complications are low and likely related to trauma severity. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. Atypical anterior wall fracture of the acetabulum: case series of anterior acetabular rim fracture without involvement of the pelvic brim.

    PubMed

    Lenarz, Christopher J; Moed, Berton R

    2007-09-01

    The purpose of this study was to describe a form of anterior wall acetabular fracture, which has been inadequately defined in the literature. Retrospective analysis of consecutive patients. Level 1 trauma center. A retrospective analysis of consecutive acetabulum patients treated by a single surgeon between 1999 and 2005 identified 6 patients with a form of anterior wall fracture without involvement of the pelvic brim. All fractures were treated operatively. Open reduction and internal fixation through an anterior surgical approach. Final radiographic appearance and modified Merle d'Aubigne score. All 6 cases demonstrated characteristics of an atypical fracture of the anterior wall, involving the anterior rim of the acetabulum similar in nature to those described for the posterior wall, rather than the standard anterior wall fracture type described by Letournel. Of the 6 cases that were identified, 5 had follow-up 1 year or greater with a mean modified Merle d'Aubigne Score of 17 (range: 17-18). A form of anterior wall acetabular fracture exists, which involves the anterior acetabular rim without involvement of the pelvic brim. It can occur in young patients with high-energy mechanisms of injury, as well as in the elderly with low-energy trauma. With appropriate surgical management, using a modified Smith-Peterson approach, good to excellent clinical outcomes should be expected.

  1. A retrospective study of eyeball rupture in patients with or without orbital fracture

    PubMed Central

    Chen, Xiang; Yao, Yi; Wang, Fengxiang; Liu, Tiecheng; Zhao, Xiao

    2017-01-01

    Abstract To summarize the clinical features of eyeball rupture with or without orbital fracture and explore the differences between them. In all, 197 patients were observed, and the following data were recorded: sex, age, time of injury, place of injury, cause of trauma, zone of eye injury, intraocular content prolapse, surgical methods and the therapeutic process, visual acuity after injury, and the final best corrected visual acuity. The results were analyzed for statistically significant differences. There was no significant difference (P > .05) in the age, sex, or cause of injury. Patients with eyeball rupture with fracture had poorer vision than did those in the simple eyeball rupture group; eyeball rupture with fracture also had a higher probability of enucleation. In this study, the clinical results show that prognosis of eyeball rupture with orbital fracture is worse than that of eyeball rupture without orbital fracture. PMID:28614230

  2. A retrospective study of eyeball rupture in patients with or without orbital fracture.

    PubMed

    Chen, Xiang; Yao, Yi; Wang, Fengxiang; Liu, Tiecheng; Zhao, Xiao

    2017-06-01

    To summarize the clinical features of eyeball rupture with or without orbital fracture and explore the differences between them.In all, 197 patients were observed, and the following data were recorded: sex, age, time of injury, place of injury, cause of trauma, zone of eye injury, intraocular content prolapse, surgical methods and the therapeutic process, visual acuity after injury, and the final best corrected visual acuity. The results were analyzed for statistically significant differences.There was no significant difference (P > .05) in the age, sex, or cause of injury. Patients with eyeball rupture with fracture had poorer vision than did those in the simple eyeball rupture group; eyeball rupture with fracture also had a higher probability of enucleation.In this study, the clinical results show that prognosis of eyeball rupture with orbital fracture is worse than that of eyeball rupture without orbital fracture.

  3. Early Versus Late Weight-Bearing Protocols for Surgically Managed Posterior Wall Acetabular Fractures.

    PubMed

    Heare, Austin; Kramer, Nicholas; Salib, Christopher; Mauffrey, Cyril

    2017-07-01

    Despite overall improved outcomes with open reduction and internal fixation of acetabular fractures, posterior wall fractures show disproportionately poor results. The effect of weight bearing on outcomes of fracture management has been investigated in many lower extremity fractures, but evidence-based recommendations in posterior wall acetabular fractures are lacking. The authors systematically reviewed the current literature to determine if a difference in outcome exists between early and late postoperative weight-bearing protocols for surgically managed posterior wall acetabular fractures. PubMed and MEDLINE were searched for posterior wall acetabular fracture studies that included weight-bearing protocols and Merle d'Aubigné functional scores. Twelve studies were identified. Each study was classified as either early or late weight bearing. Early weight bearing was defined as full, unrestricted weight bearing at or before 12 weeks postoperatively. Late weight bearing was defined as restricted weight bearing for greater than 12 weeks postoperatively. The 2 categories were then compared by functional score using a 2-tailed t test and by complication rate using chi-square analysis. Six studies (152 fractures) were placed in the early weight-bearing category. Six studies (302 fractures) were placed in the late weight-bearing category. No significant difference in Merle d'Aubigné functional scores was found between the 2 groups. No difference was found regarding heterotopic ossification, avascular necrosis, superficial infections, total infections, or osteoarthritis. This systematic review found no difference in functional outcome scores or complication rates between early and late weight-bearing protocols for surgically treated posterior wall fractures. [Orthopedics. 2017: 40(4):e652-e657.]. Copyright 2017, SLACK Incorporated.

  4. Management of orbital fractures: challenges and solutions

    PubMed Central

    Boyette, Jennings R; Pemberton, John D; Bonilla-Velez, Juliana

    2015-01-01

    Many specialists encounter and treat orbital fractures. The management of these fractures is often challenging due to the impact that they can have on vision. Acute treatment involves a thorough clinical examination and management of concomitant ocular injuries. The clinical and radiographic findings for each individual patient must then be analyzed for the need for surgical intervention. Deformity and vision impairment can occur from these injuries, and while surgery is intended to prevent these problems, it can also create them. Therefore, surgical approach and implant selection should be carefully considered. Accurate anatomic reconstruction requires complete assessment of fracture margins and proper implant contouring and positioning. The implementation of new technologies for implant shaping and intraoperative assessment of reconstruction will hopefully lead to improved patient outcomes. PMID:26604678

  5. Operative fixation of chest wall fractures: an underused procedure?

    PubMed

    Richardson, J David; Franklin, Glen A; Heffley, Susan; Seligson, David

    2007-06-01

    Chest wall fractures, including injuries to the ribs and sternum, usually heal spontaneously without specific treatment. However, a small subset of patients have fractures that produce overlying bone fragments that may produce severe pain, respiratory compromise, and, if untreated mechanically, result in nonunion. We performed open reduction and internal fixation on seven patients with multiple rib fractures-five in the initial hospitalization and two delayed--as well as 35 sternal fractures (19 immediate fixation and 16 delayed). Operative fixation was accomplished using titanium plates and screws in both groups of patients. All patients with rib fractures did well; there were no major complications or infections, and no plates required removal. Clinical results were excellent. There was one death in the sternal fracture group in a patient who was ventilator-dependent preoperatively and extubated himself in the early postoperative period. Otherwise, the results were excellent, with no complications occurring in this group. Three patients had their plates removed after boney union was achieved. No evidence of infection or nonunion occurred. The excellent results achieved in the subset of patients with severe chest wall deformities treated initially at our institution and those referred from outside suggest that operative fixation is a useful modality that is likely underused.

  6. Acoustic and optical borehole-wall imaging for fractured-rock aquifer studies

    USGS Publications Warehouse

    Williams, J.H.; Johnson, C.D.

    2004-01-01

    Imaging with acoustic and optical televiewers results in continuous and oriented 360?? views of the borehole wall from which the character, relation, and orientation of lithologic and structural planar features can be defined for studies of fractured-rock aquifers. Fractures are more clearly defined under a wider range of conditions on acoustic images than on optical images including dark-colored rocks, cloudy borehole water, and coated borehole walls. However, optical images allow for the direct viewing of the character of and relation between lithology, fractures, foliation, and bedding. The most powerful approach is the combined application of acoustic and optical imaging with integrated interpretation. Imaging of the borehole wall provides information useful for the collection and interpretation of flowmeter and other geophysical logs, core samples, and hydraulic and water-quality data from packer testing and monitoring. ?? 2003 Elsevier B.V. All rights reserved.

  7. Original endoscopic orbital decompression of lateral wall through hairline approach for Graves' ophthalmopathy: an innovation of balanced orbital decompression.

    PubMed

    Gong, Yi; Yin, Jiayang; Tong, Boding; Li, Jingkun; Zeng, Jiexi; Zuo, Zhongkun; Ye, Fei; Luo, Yongheng; Xiao, Jing; Xiong, Wei

    2018-01-01

    Orbital decompression is an important surgical procedure for treatment of Graves' ophthalmopathy (GO), especially in women. It is reasonable for balanced orbital decompression of the lateral and medial wall. Various surgical approaches, including endoscopic transnasal surgery for medial wall and eye-side skin incision surgery for lateral wall, are being used nowadays, but many of them lack the validity, safety, or cosmetic effect. Endoscopic orbital decompression of lateral wall through hairline approach and decompression of medial wall via endoscopic transnasal surgery was done to achieve a balanced orbital decompression, aiming to improve the appearance of proptosis and create conditions for possible strabismus and eyelid surgery afterward. From January 29, 2016 to February 14, 2017, this surgery was performed on 41 orbits in 38 patients with GO, all of which were at inactive stage of disease. Just before surgery and at least 3 months after surgery, Hertel's ophthalmostatometer and computed tomography (CT) were used to check proptosis and questionnaires of GO quality of life (QOL) were completed. The postoperative retroversion of eyeball was 4.18±1.11 mm (Hertel's ophthalmostatometer) and 4.17±1.14 mm (CT method). The patients' QOL was significantly improved, especially the change in appearance without facial scar. The only postoperative complication was local soft tissue depression at temporal region. Obvious depression occurred in four cases (9.76%), which can be repaired by autologous fat filling. This surgery is effective, safe, and cosmetic. Effective balanced orbital decompression can be achieved by using this original and innovative surgery method. The whole manipulation is safe and controllable under endoscope. The postoperative scar of endoscopic surgery through hairline approach is covered by hair and the anatomic structure of anterior orbit is not impacted.

  8. Accuracy and predictability in use of AO three-dimensionally preformed titanium mesh plates for posttraumatic orbital reconstruction: a pilot study.

    PubMed

    Scolozzi, Paolo; Momjian, Armen; Heuberger, Joris; Andersen, Elene; Broome, Martin; Terzic, Andrej; Jaques, Bertrand

    2009-07-01

    The aim of this study was to prospectively evaluate the accuracy and predictability of new three-dimensionally preformed AO titanium mesh plates for posttraumatic orbital wall reconstruction.We analyzed the preoperative and postoperative clinical and radiologic data of 10 patients with isolated blow-out orbital fractures. Fracture locations were as follows: floor (N = 7; 70%), medial wall (N = 1; 1%), and floor/medial wall (N = 2; 2%). The floor fractures were exposed by a standard transconjunctival approach, whereas a combined transcaruncular transconjunctival approach was used in patients with medial wall fractures. A three-dimensional preformed AO titanium mesh plate (0.4 mm in thickness) was selected according to the size of the defect previously measured on the preoperative computed tomographic (CT) scan examination and fixed at the inferior orbital rim with 1 or 2 screws. The accuracy of plate positioning of the reconstructed orbit was assessed on the postoperative CT scan. Coronal CT scan slices were used to measure bony orbital volume using OsiriX Medical Image software. Reconstructed versus uninjured orbital volume were statistically correlated.Nine patients (90%) had a successful treatment outcome without complications. One patient (10%) developed a mechanical limitation of upward gaze with a resulting handicapping diplopia requiring hardware removal. Postoperative orbital CT scan showed an anatomic three-dimensional placement of the orbital mesh plates in all of the patients. Volume data of the reconstructed orbit fitted that of the contralateral uninjured orbit with accuracy to within 2.5 cm(3). There was no significant difference in volume between the reconstructed and uninjured orbits.This preliminary study has demonstrated that three-dimensionally preformed AO titanium mesh plates for posttraumatic orbital wall reconstruction results in (1) a high rate of success with an acceptable rate of major clinical complications (10%) and (2) an anatomic

  9. Transconjunctival orbital emphysema caused by compressed air injury: a case report.

    PubMed

    Mathew, Sunu; Vasu, Usha; Francis, Febson; Nazareth, Colin

    2008-01-01

    Orbital emphysema following conjunctival tear in the absence of orbital wall fracture, caused by air under pressure is rare. Usually orbital emphysema is seen in facial trauma associated with damage to the adjacent paranasal sinuses or facial bones. To the best of our knowledge, there have been only eight reports of orbital emphysema following use of compressed air during industrial work. The air under pressure is pushed through the subconjunctival space into the subcutaneous and retrobulbar spaces. We present here a rare cause of orbital emphysema in a young man working with compressed air gun. Although the emphysema was severe, there were no orbital bone fracture and the visual recovery of the patient was complete without attendant complications.

  10. Delayed onset porous polyethylene implant-related inflammation after orbital blowout fracture repair: four case reports.

    PubMed

    Aryasit, Orapan; Ng, Danny S; Goh, Alice S C; Woo, Kyung In; Kim, Yoon-Duck

    2016-07-07

    Porous polyethylene implants are commonly used in orbital blowout fracture repair because of purported biocompatibility, durability, and low frequency of complications. Delayed inflammation related to porous polyethylene sheet implants is very rare and no case series of this condition have been reported. This is a retrospective review of clinical presentations, radiographic findings, histopathological findings, treatments, and outcomes of patients who developed delayed complications in orbital blowout fracture repair using porous polyethylene sheets. Four male patients were included with a mean age of 49 years (range 35-69 years). Blowout fracture repair was complicated with implant-related inflammation 10 months, 2 years, 3 years, and 8 years after surgery. Chronic and subacute orbital inflammatory signs were noted in two patients and acute fulminant orbital inflammation was found in two patients. Three patients developed peri-implant abscesses and one patient had a soft tissue mass around the implant. All patients underwent implant removal and two of these patients with paranasal sinusitis had sinus surgery. Histopathological findings revealed chronic inflammatory changes with fibrosis, and one patient had foreign body granuloma with culture positive Staphylococcus aureus. Delayed complications with porous polyethylene sheets used in orbital blowout fracture repair may occur many years following the initial surgery in immunocompetent patients. Low-grade or fulminant inflammation could complicate blowout fracture repair related with the implant.

  11. Evolution of dispersion coefficient in the single rough-walled fracture before and after circulated flow near the wall

    NASA Astrophysics Data System (ADS)

    Lee, S.; Yeo, I.; Lee, K.

    2012-12-01

    Understanding detailed solute transport mechanism in a single fracture is required to expand it to the complex fractured medium. Dispersion in the variable-aperture fractures occurs by combined effects of molecular diffusion, macro dispersion and Taylor dispersion. It has been reported that Taylor dispersion which is proportional to the square of the velocity dominates for the high velocity, while macro dispersion is proportional to the velocity. Contributions of each scheme are different as the velocity changes. To investigate relationship between Reynolds number and dispersion coefficient, single acrylic rough-walled fracture which has 20 cm length and 1.03 mm average aperture was designed. In this experiment, dispersion coefficient was calculated at the middle of the fracture and at the edge of the fracture via moment analysis using breakthrough curve (BTC) of fluorescent solute under the Reynolds number 0.08, 0.28, 2.78, 8.2 and 16.4. In the results, distinct dispersion regime was observed at the highly rough-walled fracture, which is inconsistent with the model that was suggested by previous research. In the range of Re < 2.78, the dispersion coefficient was proportional to the power of n (1 2.78. The reason of this transition zone was related to the generation of circulated flow near the wall. It can flush the trapped contaminant out to the main flow channel, which makes tailing effect diminished. Also, these circulation zones were visualized using microscope, CCD camera and fluorescent particles.

  12. Transconjunctival orbital emphysema caused by compressed air injury: A case report

    PubMed Central

    Vasu, Usha; Francis, Febson; Nazareth, Colin

    2008-01-01

    Orbital emphysema following conjunctival tear in the absence of orbital wall fracture, caused by air under pressure is rare. Usually orbital emphysema is seen in facial trauma associated with damage to the adjacent paranasal sinuses or facial bones. To the best of our knowledge, there have been only eight reports of orbital emphysema following use of compressed air during industrial work. The air under pressure is pushed through the subconjunctival space into the subcutaneous and retrobulbar spaces. We present here a rare cause of orbital emphysema in a young man working with compressed air gun. Although the emphysema was severe, there were no orbital bone fracture and the visual recovery of the patient was complete without attendant complications. PMID:18417833

  13. The medial femoral wall can play a more important role in unstable intertrochanteric fractures compared with lateral femoral wall: a biomechanical study.

    PubMed

    Nie, Boyuan; Chen, Xueying; Li, Jing; Wu, Dou; Liu, Qiang

    2017-12-28

    The major objective of the present study is to investigate the differences in the load and strain changes in the intertrochanteric region of human cadaveric femora between the loss of medial or lateral wall and after treatment with proximal femoral nail antirotation (PFNA). After measuring the geometry of the proximal femur region and modeling the medial or lateral wall defect femoral models, six pairs of freshly frozen human femora were randomly assigned in the medial or lateral wall group. According to a single-leg stance model, an axial loading was applied, and the strain distribution was measured before and after PFNA implantation. The strains of each specimen were recorded at load levels of 350, 700, and 1800 N and the failure load. Paired t test was performed to assess the differences between two groups. The failure mode of almost all defect model femora was consistent with that of the simulated type of intertrochanteric fractures. After the PFNA implantation, the failure mode of almost all stabilized femora was caused by new lateral wall fractures. The failure load of the lateral wall group for defect model femora was significantly higher than that of the medial wall group (p < 0.001). However, the difference disappeared after the PFNA was implanted (p = 0.990). The axial stiffness in all defect model femora showed the same results (p < 0.001). After the PFNA implantation, the axial stiffness of the lateral wall group remained higher than that of the medial wall group (p = 0.001). However, the axial stiffness of the lateral wall group showed that the femora removed from the lateral wall were higher than the PFNA-stabilized femora (p = 0.020). For the axial strain in the anterior wall after the PFNA implantation, the strain of the lateral wall group was significantly lower than that of the medial group (p = 0.003). Nevertheless, for the axial strain of the posterior wall after the PFNA implantation, the strain of the medial wall group

  14. Successful application of endoscopic modified medial maxillectomy to orbital floor trapdoor fracture in a pediatric patient.

    PubMed

    Matsuda, Yasunori; Sakaida, Hiroshi; Kobayashi, Masayoshi; Takeuchi, Kazuhiko

    2016-10-01

    Although surgical treatment of orbital floor fractures can be performed by many different approaches, the application of endoscopic modified medial maxillectomy (EMMM) for this condition has rarely been described in the literature. We report on a case of a 7-year-old boy with a trapdoor orbital floor fracture successfully treated with the application of EMMM. The patient suffered trauma to the right orbit floor and the inferior rectus was entrapped at the orbital floor. Initially, surgical repair via endoscopic endonasal approach was attempted. However, we were unable to adequately access the orbital floor through the maxillary ostium. Therefore, an alternative route of access to the orbital floor was established by EMMM. With sufficient visualization and operating space, the involved orbital content was completely released from the entrapment site and reduced into the orbit. To facilitate wound healing, the orbital floor was supported with a water-inflated urethral balloon catheter for 8 days. At follow-up 8 months later, there was no gaze restriction or complications associated with the EMMM. This case illustrates the efficacy and safety of EMMM in endoscopic endonasal repair of orbital floor fracture, particularly for cases with a narrow nasal cavity such as in pediatric patients. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. The effect of variable size posterior wall acetabular fractures on contact characteristics of the hip joint.

    PubMed

    Olson, S A; Bay, B K; Pollak, A N; Sharkey, N A; Lee, T

    1996-01-01

    The indications for open reduction and internal fixation of posterior wall acetabular fractures associated with a clinically stable hip joint are unclear. In previous work a large posterior wall defect (27% articular surface area) resulted in significant alteration of load transmission across the hip; specifically, there was a transition from evenly distributed loading along the acetabular articular surface to loading concentrated mainly in the superior portion of the articular surface during simulated single leg stance. However, the majority of posterior wall fractures involve a smaller amount of the articular surface. Posterior wall acetabular fractures not associated with instability of the hip are commonly treated nonoperatively. This practice does not account for the size of the posterior wall fracture. To study the biomechanical consequences of variably sized articular defects, a laboratory experiment was conducted evaluating three progressively larger posterior wall defects of the acetabulum during simulated single leg stance using superlow Fuji prescale film (Itochu International, New York): (a) 1/3 articular surface width through a 50 degrees arc along the posterior wall of the acetabulum, (b) 2/3, and (c) 3/3 articular width defects through the same 50 degrees arc along the posterior wall of the acetabulum. In the intact acetabulum, 48% of the total articular contact was located in the superior acetabulum. Twenty-eight percent of articular contact was in the anterior wall region of the acetabulum and 24% in the posterior wall region. After the 1/3 width posterior wall defect, 64% of the articular contact was located in the superior acetabulum (p = 0.0011). The 2/3 width posterior wall defect resulted in 71% of articular contact area being located in the superior acetabulum (p = 0.0006). After the 3/3 width posterior wall defect, 77% of articular contact was located in the superior acetabulum, significantly greater than the intact condition (p < 0

  16. The stability of steady motion of magnetic domain wall: Role of higher-order spin-orbit torques

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

    He, Peng-Bin, E-mail: hepengbin@hnu.edu.cn; Yan, Han; Cai, Meng-Qiu

    The steady motion of magnetic domain wall driven by spin-orbit torques is investigated analytically in the heavy/ferromagnetic metal nanowires for three cases with a current transverse to the in-plane and perpendicular easy axis, and along the in-plane easy axis. By the stability analysis of Walker wall profile, we find that if including the higher-order spin-orbit torques, the Walker breakdown can be avoided in some parameter regions of spin-orbit torques with a current transverse to or along the in-plane easy axis. However, in the case of perpendicular anisotropy, even considering the higher-order spin-orbit torques, the velocity of domain wall cannot bemore » efficiently enhanced by the current. Furthermore, the direction of wall motion is dependent on the configuration and chirality of domain wall with a current along the in-plane easy axis or transverse to the perpendicular one. Especially, the direction of motion can be controlled by the initial chirality of domain wall. So, if only involving the spin-orbit mechanism, it is preferable to adopt the scheme of a current along the in-plane easy axis for enhancing the velocity and controlling the direction of domain wall.« less

  17. Comparative study of comminuted posterior acetabular wall fracture treated with the Acetabular Tridimensional Memory Fixation System.

    PubMed

    Zhang, Yuntong; Zhao, Xue; Tang, Yang; Zhang, Chuncai; Xu, Shuogui; Xie, Yang

    2014-04-01

    Posterior wall fractures are one of the most common acetabular fractures. However, only 30% of these fractures involve a single large fragment, and comminuted acetabular posterior wall fractures pose a particular surgical challenge. The purpose of this study was to compare outcomes between patients who received fixation for comminuted posterior wall fracture using the Acetabular Tridimensional Memory Fixation System (ATMFS) and patients who underwent fixation with conventional screws and buttress plates (Plates group). Between April 2003 and May 2007, 196 consecutive patients who sustained a comminuted posterior wall fracture of acetabulum were treated with ATMFS or conventional screws and buttress plates. Operative time, fluoroscopy time, blood loss, and any intra-operative complications were recorded. Plain AP and lateral radiographs were obtained at all visits (Matta's criteria). Modified Merle d' Aubigne-Postel score, and Mos SF-36 score were compared between groups. Fifty patients were included in the analysis with 26 in the ATMFS group and 24 in the Plates group. The mean follow-up time was 57.5 months, ranging from 31 to 69 months. All patients had fully healed fractures at the final follow-up. There was no difference in clinical outcomes or radiological evaluations between groups. Patients with comminuted posterior wall fractures of the acetabulum treated with the ATMFS or conventional screws and buttress plate techniques achieve a good surgical result. Both techniques are safe, reliable, and practical. Use of the ATMFS technique may reduce blood loss and improve rigid support to marginal bone impaction. The use ATMFS may need additional support when fractures involve the superior roof. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Prediction and Experimental Evidence for Thermodynamically Stable Charged Orbital Domain Walls

    DOE PAGES

    Li, Qing’an; Gray, K. E.; Wilkins, S. B.; ...

    2014-08-18

    On theoretical grounds, we show that orbital domain walls (ODWs), which are known to exist in the charge and orbital ordered layered manganite LaSr 2Mn 2O 7, should be partially charged as a result of competition between orbital-induced strain and Coulomb repulsion. Furthermore, this unexpected result provides the necessary condition for the known thermodynamic stability of these ODWs, which are unlike the more typical domain walls that arise only from an external field. We offer experimental data consistent with this theoretical framework through a combined transport and x-ray-diffraction study. In particular, our transport data on this charge and orbital orderedmore » manganite exhibit abrupt transformations to higher conductance at a threshold electric field. As transport phenomena closely resemble effects found for sliding charge-density waves (SCDWs) in pseudo-one-dimensional (1D) materials, a SCDW along such pseudo-1D ODWs provides a natural explanation of our data. Importantly, x-ray-diffraction data eliminate heating and melting of charge order as tenable alternative explanations of our data.« less

  19. [Reconstruction of maxillary sinus superior wall fractures with calcium phosphate cement/recombinant human bonemorphogenetic protein 7 compound implanted material in rabbit].

    PubMed

    Zhang, Qunhui; Yu, Feng; Zhang, Haoliang; Gong, Huicheng; Lin, Ying

    2015-11-01

    To evaluate the osteogenetic character and repairing maxillary sinus superior wall fractures capability of calcium phosphate cement (CPC) before and after combined with recombinant human bone morphogenetie protein-7(rhBMP-7). A 10 mmX5 mm bone defect in the maxillary sinus superior wall was induced by surgery in all 24 New Zealand white rabbits. These 24 rabbits were randomly divided into two groups. The defects were repaired with CPC group (n = 12) and CPC/rhBMP-7 group (n = 12). The osteogenesis of bone defect was monitored by gro'ss observation, histological examination, observation under scanning electron microscope and measurement of ALP activity at 6 and 12 weeks after the implantation. In group CPC,new bone was found to form slowly and little by little. In group CPC/rhBMP-7, however, new bone was observed to form early and massively. The ALP activity in group CPC showed significant statistical difference with that of group CPC/rhBMP-7 (P < 0.05). The CPC/rhBMP-7 composite has osteoconductibility and osteoinductibility, comparing the use of CPC/rhBMP-7 with CPC for the repair of orbital fracture, the former show obvious advantage repairing ability in maxillary sinus superior wall defect.

  20. Laboratory research of hydraulic fracturing with tangential loading of borehole wall

    NASA Astrophysics Data System (ADS)

    Kurlenya, MV; Patutin, AV; Rybalkin, LA; Serdyukov, SV; Shilova, TV

    2017-02-01

    Under study is transverse fracturing of an organic glass block through secondary shearing stress applied to the borehole wall. To this effect, a system composed of a press sealer and a collet anchor manufactured in two options has been designed. It is shown than an anchor with a circular groove allows reducing breakdown pressure and enables effective transverse fracture at the borehole bottom.

  1. Hydraulic properties of 3D rough-walled fractures during shearing: An experimental study

    NASA Astrophysics Data System (ADS)

    Yin, Qian; Ma, Guowei; Jing, Hongwen; Wang, Huidong; Su, Haijian; Wang, Yingchao; Liu, Richeng

    2017-12-01

    This study experimentally analyzed the influence of shear processes on nonlinear flow behavior through 3D rough-walled rock fractures. A high-precision apparatus was developed to perform stress-dependent fluid flow tests of fractured rocks. Then, water flow tests on rough-walled fractures with different mechanical displacements were conducted. At each shear level, the hydraulic pressure ranged from 0 to 0.6 MPa, and the normal load varied from 7 to 35 kN. The results show that (i) the relationship between the volumetric flow rate and hydraulic gradient of rough-walled fractures can be well fit using Forchheimer's law. Notably, both the linear and nonlinear coefficients in Forchheimer's law decrease during shearing; (ii) a sixth-order polynomial function is used to evaluate the transmissivity based on the Reynolds number of fractures during shearing. The transmissivity exhibits a decreasing trend as the Reynolds number increases and an increasing trend as the shear displacement increases; (iii) the critical hydraulic gradient, critical Reynolds number and equivalent hydraulic aperture of the rock fractures all increase as the shear displacement increases. When the shear displacement varies from 0 to 15 mm, the critical hydraulic gradient ranges from 0.3 to 2.2 for a normal load of 7 kN and increases to 1.8-8.6 for a normal load of 35 kN; and (iv) the Forchheimer law results are evaluated by plotting the normalized transmissivity of the fractures during shearing against the Reynolds number. An increase in the normal load shifts the fitted curves downward. Additionally, the Forchheimer coefficient β decreases with the shear displacement but increases with the applied normal load.

  2. Orbital fractures treated in Auckland from 2010-2015: review of patient outcomes.

    PubMed

    Anand, Lanit; Sealey, Christopher

    2017-07-07

    The purpose of this study was to review patient outcomes from surgical reconstruction of isolated orbital fractures, performed by the Auckland District Health Board (ADHB) Oral and Maxillofacial Surgery service (OMFS), from 2010 to 2015. In particular, we wished to assess titanium as an orbital reconstructive material and compare outcomes with the international literature. Hospital records for 103 adults (>18 years old) who underwent repair of isolated orbital fractures by the OMFS department at Middlemore Hospital, between 2010 and 2015, were reviewed. Information collected included patient characteristics, cause of injury, type of reconstruction material used and post-operative complications. Patients were then followed up by means of a verbal telephone questionnaire. The majority of patients were male in the 18-30 year age group, with interpersonal violence being the leading cause of injury. Titanium was the preferred choice of reconstructive material. Seven patients required return to theatre to resolve post-operative complications. Sixty-four patients could be contacted by telephone (12 months to six years follow-up). Thirty patients, who could not be contacted by telephone, did attend clinic follow-up and were assessed from their hospital records (minimum of one month follow-up). Ten patients could not be contacted by telephone and had not attended clinic follow-up. Problems with diplopia, paraesthesia and cosmesis were within complication rates reported in the literature. Patients with isolated orbital fractures, treated by the Oral and Maxillofacial Surgery Department in Auckland from 2010-2015, were reviewed. Titanium was the most commonly used reconstructive material and proved to be well tolerated. Complication rates were within international norms.

  3. The Hydraulic Mechanism in the Orbital Blowout Fracture Because of a High-Pressure Air Gun Injury.

    PubMed

    Kang, Seok Joo; Chung, Eui Han

    2015-10-01

    There are 2 predominant mechanisms that are used to explain the pathogenesis of orbital blowout fracture; these include hydraulic and buckling mechanisms. Still, however, its pathophysiology remains uncertain. To date, studies in this series have been conducted using dry skulls, cadavers, or animals. But few clinical studies have been conducted to examine whether the hydraulic mechanism is involved in the occurrence of pure orbital blowout fracture. The authors experienced a case of a 52-year-old man who had a pure medial blowout fracture after sustaining an eye injury because of a high-pressure air gun. Our case suggests that surgeons should be aware of the possibility that the hydraulic mechanism might be involved in the blowout fracture in patients presenting with complications, such as limitation of eye movement, diplopia, and enophthalmos.

  4. Presence of a groove in the lateral wall of the human orbit.

    PubMed Central

    Santo Neto, H; Penteado, C V; de Carvalho, V C

    1984-01-01

    The presence of a groove in the lateral wall of the human orbit (Royle, 1973) was found in 45 of 100 orbits examined (45%). In 15 skulls the groove was present bilaterally. The groove probably lodges an anastomosis between the middle meningeal and infraorbital blood vessels. No reference to this groove was found in general anatomical texts. Images Fig. 1 PMID:6746401

  5. Surgical management of temple-related problems following lateral wall rim-sparing orbital decompression for thyroid-related orbitopathy.

    PubMed

    Siah, We Fong; Patel, Bhupendra Ck; Malhotra, Raman

    2016-08-01

    To report a case series of patients with persistent temple-related problems following lateral wall rim-sparing (LWRS) orbital decompression for thyroid-related orbitopathy and to discuss their management. Retrospective review of medical records of patients referred to two oculoplastic centres (Corneoplastic Unit, Queen Victoria Hospital, East Grinstead, UK and Moran Eye Center, University of Utah, Salt Lake City, USA) for intervention to improve/alleviate temple-related problems. All patients were seeking treatment for their persistent, temple-related problems of minimum 3 years' duration post decompression. The main outcome measure was the resolution or improvement of temple-related problems. Eleven orbits of six patients (five females) with a median age of 57 years (range 23-65) were included in this study. Temple-related problems consisted of cosmetically bothersome temple hollowness (n=11; 100%), masticatory oscillopsia (n=8; 73%), temple tenderness (n=4; 36%), 'clicking' sensation (n=4; 36%) and gaze-evoked ocular pain (n=4; 36%). Nine orbits were also complicated by proptosis and exposure keratopathy. Preoperative imaging studies showed the absence of lateral wall in all 11 orbits and evidence of prolapsed lacrimal gland into the wall defect in four orbits. Intervention included the repair of the lateral wall defect with a sheet implant, orbital decompression involving fat, the medial wall or orbital floor and autologous fat transfer or synthetic filler for temple hollowness. Postoperatively, there was full resolution of masticatory oscillation, temple tenderness, 'clicking' sensation and gaze-evoked ocular pain, and an improvement in temple hollowness. Pre-existing diplopia in one patient resolved after surgery while two patients developed new-onset diplopia necessitating strabismus surgery. This is the first paper to show that persistent, troublesome temple-related problems following LWRS orbital decompression can be surgically corrected. Patients

  6. [Medpor plus titanic mesh implant in the repair of orbital blowout fractures].

    PubMed

    Han, Xiao-hui; Zhang, Jia-yu; Cai, Jian-qiu; Shi, Ming-guang

    2011-05-10

    To study the efficacy of porous polyethylene (Medpor) plus titanic mesh sheets in the repair of orbital blowout fractures. A total of 20 patients underwent open surgical reduction with the combined usage of Medpor and titanic mesh. And they were followed up for average period of 14.5 months (range: 9 - 18). There is no infection or extrusion of medpor and titanic mesh in follow-up periods. There was no instance of decreased visual acuity at post-operation. And all cases of enophthalmos were corrected. The post-operative protrusion degree of both eyes was almost identical at less than 2 mm. The movement of eye balls was satisfactory in all directions. Diplopia disappeared in 18 cases with a cure rate of 90%, 1 case improved and 1 case persisted. Medpor plus titanic mesh implant is a safe and effective treatment in the repair of orbital blow out fractures.

  7. Technique for repair of fractures and separations involving the cartilaginous portions of the anterior chest wall.

    PubMed

    Bonne, Stephanie L; Turnbull, Isaiah R; Southard, Robert E

    2015-06-01

    Internal fixation of the ribs has been shown in numerous studies to decrease complications following traumatic rib fractures. Anterior injuries to the chest wall causing cartilaginous fractures, although rare, can cause significant disability and can lead to a variety of complications and, therefore, pose a unique clinical problem. Here, we report the surgical technique used for four patients with internal fixation of injuries to the cartilaginous portions of the chest wall treated at our center. All patients had excellent clinical outcomes and reported improvement in symptoms, with no associated complications. Patients who have injuries to the anterior portions of the chest wall should be considered for internal fixation of the chest wall when the injuries are severe and can lead to clinical disability.

  8. An improved two-dimensional depth-integrated flow equation for rough-walled fractures

    NASA Astrophysics Data System (ADS)

    Mallikamas, Wasin; Rajaram, Harihar

    2010-08-01

    We present the development of an improved 2-D flow equation for rough-walled fractures. Our improved equation accounts for the influence of midsurface tortuosity and the fact that the aperture normal to the midsurface is in general smaller than the vertical aperture. It thus improves upon the well-known Reynolds equation that is widely used for modeling flow in fractures. Unlike the Reynolds equation, our approach begins from the lubrication approximation applied in an inclined local coordinate system tangential to the fracture midsurface. The local flow equation thus obtained is rigorously transformed to an arbitrary global Cartesian coordinate system, invoking the concepts of covariant and contravariant transformations for vectors defined on surfaces. Unlike previously proposed improvements to the Reynolds equation, our improved flow equation accounts for tortuosity both along and perpendicular to a flow path. Our approach also leads to a well-defined anisotropic local transmissivity tensor relating the representations of the flux and head gradient vectors in a global Cartesian coordinate system. We show that the principal components of the transmissivity tensor and the orientation of its principal axes depend on the directional local midsurface slopes. In rough-walled fractures, the orientations of the principal axes of the local transmissivity tensor will vary from point to point. The local transmissivity tensor also incorporates the influence of the local normal aperture, which is uniquely defined at each point in the fracture. Our improved flow equation is a rigorous statement of mass conservation in any global Cartesian coordinate system. We present three examples of simple geometries to compare our flow equation to analytical solutions obtained using the exact Stokes equations: an inclined parallel plate, and circumferential and axial flows in an incomplete annulus. The effective transmissivities predicted by our flow equation agree very well with values

  9. Spin-orbit coupling and the static polarizability of single-wall carbon nanotubes

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

    Diniz, Ginetom S., E-mail: ginetom@gmail.com; Ulloa, Sergio E.

    2014-07-14

    We calculate the static longitudinal polarizability of single-wall carbon tubes in the long wavelength limit taking into account spin-orbit effects. We use a four-orbital orthogonal tight-binding formalism to describe the electronic states and the random phase approximation to calculate the dielectric function. We study the role of both the Rashba as well as the intrinsic spin-orbit interactions on the longitudinal dielectric response, i.e., when the probing electric field is parallel to the nanotube axis. The spin-orbit interaction modifies the nanotube electronic band dispersions, which may especially result in a small gap opening in otherwise metallic tubes. The bandgap size andmore » state features, the result of competition between Rashba and intrinsic spin-orbit interactions, result in drastic changes in the longitudinal static polarizability of the system. We discuss results for different nanotube types and the dependence on nanotube radius and spin-orbit couplings.« less

  10. Inflammatory foreign body reaction caused by resorbable materials used for orbital fractures repair

    PubMed Central

    He, Jie; Shi, Wodong

    2017-01-01

    Abstract Rationale: Resorbable materials have been recommended for orbital fractures repair. Many literatures reported the advantages of resorbable materials in clinical applications, but few reports about complications. Patient concerns: In this study, we encountered a 14-year-old boy treated for the orbital fracture by using resorbable plate, in whom inflammatory foreign body reaction was detected. In addition, this patient had repeated history of skin allergy and upper respiratory tract infection. Diagnoses: Intraoperative observation showed that the resorbable material near the orbital rim was covered by granulation and inflammatory tissues, without purulent secretions. The histological examination revealed inflammatory foreign body reaction to the resorbable plate. Interventions: Debridement was taken to remove the mass on the left lower eyelid. At the outpatient examination, a small amount of granulation tissue was found at the incision. Then, secondary surgery for exploration and removal of the resorbable material was carried, 9 months after the first surgery. Outcomes: One month after the surgery, the skin retraction, ectropion, and edema gradually improved. Lessons: Inadequate degradation of resorbable materials and patient's medical history of allergies may cause an inflammatory foreign body reaction. Therefore, it is prudent to choose resorbable materials for patients. PMID:29245243

  11. Numerical Investigation of the Effect of the Location of Critical Rock Block Fracture on Crack Evolution in a Gob-side Filling Wall

    NASA Astrophysics Data System (ADS)

    Li, Xuehua; Ju, Minghe; Yao, Qiangling; Zhou, Jian; Chong, Zhaohui

    2016-03-01

    Generation, propagation, and coalescence of the shear and tensile cracks in the gob-side filling wall are significantly affected by the location of the fracture of the critical rock block. The Universal Discrete Element Code software was used to investigate crack evolution characteristics in a gob-side filling wall and the parameter calibration process for various strata and the filling wall was clearly illustrated. The cracks in both the filling wall and the coal wall propagate inward in a V-shape pattern with dominant shear cracks generated initially. As the distance between the fracture and the filling wall decreases, the number of cracks in the filling wall decreases, and the stability of the filling wall gradually improves; thus, by splitting the roof rock at the optimal location, the filling wall can be maintained in a stable state. Additionally, we conducted a sensitivity analysis that demonstrated that the higher the coal seam strength, the fewer cracks occur in both the filling wall and the coal wall, and the less failure they experience. With the main roof fracturing into a cantilever structure, the higher the immediate roof strength, the fewer cracks are in the filling wall. With the critical rock block fracturing above the roadway, an optimal strength of the immediate roof can be found that will stabilize the filling wall. This study presents a theoretical investigation into stabilization of the filling wall, demonstrating the significance of pre-splitting the roof rock at a desirable location.

  12. The Correlation between the Orbital Volume Ratio and Enophthalmos in Unoperated Blowout Fractures.

    PubMed

    Choi, Su Hyun; Kang, Dong Hee; Gu, Ja Hea

    2016-11-01

    Enophthalmos may not appear immediately after trauma due to periorbital swelling in a blowout fracture, and preoperative measurements of enophthalmos cannot be used as a reliable guideline. It is important to predict the eventual final extent of enophthalmos in order to determine whether to perform surgery, and there have been several attempts to predict the degree of late enophthalmos using preoperative orbital volume. The purpose of this study is to investigate the correlation between the orbital volume ratio (OVR) with final enophthalmos and the palpebral fissure, and to find the OVR that induced 2 mm of enophthalmos in unilateral unoperated blowout fractures. We retrospectively reviewed the medical records of 38 patients and divided them into 3 groups, determined by the fracture location. The relationships between the OVR and both the degree of enophthalmos and the palpebral fissure ratio (PFR) were assessed and, in particular, the OVR that induced 2 mm of enophthalmos was sought. Enophthalmos increased in proportion to the OVR, and there was a highly significant correlation between the increase in the OVR and the degree of enophthalmos (P<0.05). On the other hand, there was no correlation between OVR and PFR (P>0.05). The OVR that induced 2-mm enophthalmos was 112.18%. The final degree of enophthalmos can be estimated by the preoperative measurement of OVR. Preoperative measurements of OVR can be used as quantitative values to predict the final degree of enophthalmos in pure blowout fractures.

  13. The Correlation between the Orbital Volume Ratio and Enophthalmos in Unoperated Blowout Fractures

    PubMed Central

    Choi, Su Hyun; Gu, Ja Hea

    2016-01-01

    Background Enophthalmos may not appear immediately after trauma due to periorbital swelling in a blowout fracture, and preoperative measurements of enophthalmos cannot be used as a reliable guideline. It is important to predict the eventual final extent of enophthalmos in order to determine whether to perform surgery, and there have been several attempts to predict the degree of late enophthalmos using preoperative orbital volume. The purpose of this study is to investigate the correlation between the orbital volume ratio (OVR) with final enophthalmos and the palpebral fissure, and to find the OVR that induced 2 mm of enophthalmos in unilateral unoperated blowout fractures. Methods We retrospectively reviewed the medical records of 38 patients and divided them into 3 groups, determined by the fracture location. The relationships between the OVR and both the degree of enophthalmos and the palpebral fissure ratio (PFR) were assessed and, in particular, the OVR that induced 2 mm of enophthalmos was sought. Results Enophthalmos increased in proportion to the OVR, and there was a highly significant correlation between the increase in the OVR and the degree of enophthalmos (P<0.05). On the other hand, there was no correlation between OVR and PFR (P>0.05). The OVR that induced 2-mm enophthalmos was 112.18%. Conclusions The final degree of enophthalmos can be estimated by the preoperative measurement of OVR. Preoperative measurements of OVR can be used as quantitative values to predict the final degree of enophthalmos in pure blowout fractures. PMID:27896181

  14. Results after En Bloc Lateral Wall Decompression Surgery with Orbital Fat Resection in 111 Patients with Graves' Orbitopathy

    PubMed Central

    Fichter, Nicole; Guthoff, Rudolf F.

    2015-01-01

    Purpose. To evaluate the effect of en bloc lateral wall decompression with additional orbital fat resection in terms of exophthalmos reduction and complications. Methods. A retrospective, noncomparative case series study from 1999 to 2011 (chart review) in Graves' orbitopathy (GO) patients. The standardized surgical technique involved removal of the lateral orbital wall including the orbital rim via a lid crease approach combined with additional orbital fat resection. Exophthalmos, diplopia, retrobulbar pressure sensation, and complications were analyzed pre- and postoperatively. Results. A total of 111 patients (164 orbits) with follow-up >3 months were analysed. Mean exophthalmos reduction was 3.05mm and preoperative orbital pressure sensation resolved or improved in all patients. Visual acuity improved significantly in patients undergoing surgery for rehabilitative or vision threatening purposes. Preoperative diplopia improved in 10 patients (9.0%) but worsened in 5 patients (4.5%), necessitating surgical correction in 3 patients. There were no significant complications; however, one patient had slight hollowing of the temporalis muscle around the scar that did not necessitate revision, and another patient with a circumscribed retraction of the scar itself underwent surgical correction. Conclusions. The study confirms the efficiency of en bloc lateral wall decompression in GO in a large series of patients, highlighting the low risk of disturbance of binocular functions and of cosmetic blemish in the temporal midface region. PMID:26221142

  15. Microstructure change in wood cell wall fracture from mechanical pretreatment and its influence on enzymatic hydrolysis

    Treesearch

    Jinxue Jiang; Jinwu Wang; Xiao Zhang; Michael Wolcott

    2017-01-01

    tMechanical pretreatment is an effective process for chemical or biochemical conversion of woodybiomass. The deconstruction features of the wood cell wall play an important role in its chemical or bio-chemical processing. In this work, we evaluated the wood cell wall fracture in the early stage of mechanicalpretreatment process conducted with various initial moisture...

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

    Ball, J.B. Jr.

    Direct oblique sagittal CT was used to evaluate trauma to 77 orbits. Sixty-seven orbital wall fractures with intact orbital rims (36 floor, 22 medial wall, nine roof) were identified in 47 orbits. Since persistent diplopia and/or enophthalmos may warrant surgical repair of orbital floor fractures, optimal imaging should include an evaluation of extraocular muscle status, the nature and amount of displaced orbital contents, and an accurate definition of fracture margins. For orbital floor fractures, a combination of the direct oblique sagittal and direct coronal projections optimally displayed all fracture margins, the fracture's relationship to the inferior orbital rim and medialmore » orbital wall, and the amount of displacement into the maxillary sinus. Inferior rectus muscle status with 36 floor fractures was best seen on the direct oblique sagittal projection in 30 fractures (83.3%) and was equally well seen on sagittal and coronal projections in two fractures (5.5%). Floor fractures were missed on 100% of axial, 5.5% of sagittal, and 0% of coronal projections. Since the direct oblique sagittal projection complements the direct coronal projection in evaluating orbital floor fractures, it should not be performed alone. A technical approach to the CT evaluation or orbital wall fractures is presented.« less

  17. Orbital Wall Reconstruction with Two-Piece Puzzle 3D Printed Implants: Technical Note

    PubMed Central

    Mommaerts, Maurice Y.; Büttner, Michael; Vercruysse, Herman; Wauters, Lauri; Beerens, Maikel

    2015-01-01

    The purpose of this article is to describe a technique for secondary reconstruction of traumatic orbital wall defects using titanium implants that act as three-dimensional (3D) puzzle pieces. We present three cases of large defect reconstruction using implants produced by Xilloc Medical B.V. (Maastricht, the Netherlands) with a 3D printer manufactured by LayerWise (3D Systems; Heverlee, Belgium), and designed using the biomedical engineering software programs ProPlan and 3-Matic (Materialise, Heverlee, Belgium). The smaller size of the implants allowed sequential implantation for the reconstruction of extensive two-wall defects via a limited transconjunctival incision. The precise fit of the implants with regard to the surrounding ledges and each other was confirmed by intraoperative 3D imaging (Mobile C-arm Systems B.V. Pulsera, Philips Medical Systems, Eindhoven, the Netherlands). The patients showed near-complete restoration of orbital volume and ocular motility. However, challenges remain, including traumatic fat atrophy and fibrosis. PMID:26889349

  18. Domain wall dynamics driven by spin transfer torque and the spin-orbit field.

    PubMed

    Hayashi, Masamitsu; Nakatani, Yoshinobu; Fukami, Shunsuke; Yamanouchi, Michihiko; Mitani, Seiji; Ohno, Hideo

    2012-01-18

    We have studied current-driven dynamics of domain walls when an in-plane magnetic field is present in perpendicularly magnetized nanowires using an analytical model and micromagnetic simulations. We model an experimentally studied system, ultrathin magnetic nanowires with perpendicular anisotropy, where an effective in-plane magnetic field is developed when current is passed along the nanowire due to the Rashba-like spin-orbit coupling. Using a one-dimensional model of a domain wall together with micromagnetic simulations, we show that the existence of such in-plane magnetic fields can either lower or raise the threshold current needed to cause domain wall motion. In the presence of the in-plane field, the threshold current differs for positive and negative currents for a given wall chirality, and the wall motion becomes sensitive to out-of-plane magnetic fields. We show that large non-adiabatic spin torque can counteract the effect of the in-plane field.

  19. Controls on fault zone structure and brittle fracturing in the foliated hanging wall of the Alpine Fault

    NASA Astrophysics Data System (ADS)

    Williams, Jack N.; Toy, Virginia G.; Massiot, Cécile; McNamara, David D.; Smith, Steven A. F.; Mills, Steven

    2018-04-01

    Three datasets are used to quantify fracture density, orientation, and fill in the foliated hanging wall of the Alpine Fault: (1) X-ray computed tomography (CT) images of drill core collected within 25 m of its principal slip zones (PSZs) during the first phase of the Deep Fault Drilling Project that were reoriented with respect to borehole televiewer images, (2) field measurements from creek sections up to 500 m from the PSZs, and (3) CT images of oriented drill core collected during the Amethyst Hydro Project at distances of ˜ 0.7-2 km from the PSZs. Results show that within 160 m of the PSZs in foliated cataclasites and ultramylonites, gouge-filled fractures exhibit a wide range of orientations. At these distances, fractures are interpreted to have formed at relatively high confining pressures and/or in rocks that had a weak mechanical anisotropy. Conversely, at distances greater than 160 m from the PSZs, fractures are typically open and subparallel to the mylonitic or schistose foliation, implying that fracturing occurred at low confining pressures and/or in rocks that were mechanically anisotropic. Fracture density is similar across the ˜ 500 m width of the field transects. By combining our datasets with measurements of permeability and seismic velocity around the Alpine Fault, we further develop the hierarchical model for hanging-wall damage structure that was proposed by Townend et al. (2017). The wider zone of foliation-parallel fractures represents an outer damage zone that forms at shallow depths. The distinct < 160 m wide interval of widely oriented gouge-filled fractures constitutes an inner damage zone. This zone is interpreted to extend towards the base of the seismogenic crust given that its width is comparable to (1) the Alpine Fault low-velocity zone detected by fault zone guided waves and (2) damage zones reported from other exhumed large-displacement faults. In summary, a narrow zone of fracturing at the base of the Alpine Fault

  20. Residual diplopia in treated orbital bone fractures

    PubMed Central

    Balaji, S. M.

    2013-01-01

    Background: Residual diplopia (RD) is the main post-treatment complication of orbital bone fracture (OBF) reduction. The cause of RD is varied and often related to the degree of inflammation, surgical timing, graft requirement, and trauma to orbital musculature, fat, as well as nerves. The exact prevalence of these and the influence of these factors on RD is not widely reported in literature. Materials and Methods: This retrospective study was conducted from January 1, 2000 through December 31, 2011. Sixty nine patients fulfilling inclusion and exclusion criteria were enrolled in this study. The nature of the defect causing RD was identified. Demographics, nature of initial OBF, extent and type of treatment, and grafts were noted. Corrective surgeries were performed. Data entry and analysis were performed using SPSS. Descriptive statistics and Chi square tests were employed. P value ≤ 0.05 was taken as significant. Results: Inferior rectus muscle (71%) and other periorbital musculature (56.5%) was entrapped, leading to RD. Globe position abnormalities was observed in 52.1% of cases. Degree of inflammation, types of grafts (P = 0.000) were significantly related. Discussion: Preoperative swelling, musculature inflammation, and graft placement significantly influenced the surgical outcome of OBF. RD is related to these factors. Adequate control with OBF healing and remodeling needs to be considered while timing OBF. Author's modification with mesh and cartilage in secondary corrective surgery for RD provided an effective solution for immediate intervention. PMID:23662258

  1. [The use of titanium nickelide devices in treating fractures of the zygomatico-orbital complex].

    PubMed

    Medvedev, Iu A; Sivolapov, K A

    1993-01-01

    The authors analyze the results of surgical treatment of 78 patients with zygomatico-orbital injuries. Mini-cramps and mini-plates of titanium nickelide with thermomechanical memory were employed for fracture fixation. Surgical strategy based on osteosynthesis with the use of such devices provides a reliable fixation of bone fragments and makes the operation less traumatic.

  2. Modified lateral orbital wall decompression in Graves' orbitopathy using computer-assisted planning.

    PubMed

    Spalthoff, S; Jehn, P; Zimmerer, R; Rana, M; Gellrich, N-C; Dittmann, J

    2018-02-01

    Graves' orbitopathy, a condition seen in the autoimmune syndrome Graves' disease, affects the fatty tissue and muscles inside the orbit. Graves' orbitopathy is associated with increasing exophthalmos and sometimes leads to compressive dysthyroid optic neuropathy, resulting in progressive vision loss. Dysthyroid compressive optic neuropathy, functional problems, and cosmetic problems are the main indications for surgical decompression of the orbit, especially if conservative treatment has not led to a reduction in symptoms. Many surgical techniques are described in the literature. This article presents a modification of the lateral orbital wall osteotomy, involving the rotation and reduction of the osteotomized bone segment using preoperative planning, intraoperative computed navigation, and piezoelectric surgery. This new method combines the advantages of different techniques and appears to be a valid approach to the treatment of severe cases of Graves' orbitopathy. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  3. Inflammatory foreign body reaction caused by resorbable materials used for orbital fractures repair: A case report.

    PubMed

    He, Jie; Shi, Wodong

    2017-12-01

    Resorbable materials have been recommended for orbital fractures repair. Many literatures reported the advantages of resorbable materials in clinical applications, but few reports about complications. In this study, we encountered a 14-year-old boy treated for the orbital fracture by using resorbable plate, in whom inflammatory foreign body reaction was detected. In addition, this patient had repeated history of skin allergy and upper respiratory tract infection. Intraoperative observation showed that the resorbable material near the orbital rim was covered by granulation and inflammatory tissues, without purulent secretions. The histological examination revealed inflammatory foreign body reaction to the resorbable plate. Debridement was taken to remove the mass on the left lower eyelid. At the outpatient examination, a small amount of granulation tissue was found at the incision. Then, secondary surgery for exploration and removal of the resorbable material was carried, 9 months after the first surgery. One month after the surgery, the skin retraction, ectropion, and edema gradually improved. Inadequate degradation of resorbable materials and patient's medical history of allergies may cause an inflammatory foreign body reaction. Therefore, it is prudent to choose resorbable materials for patients.

  4. Reconstruction of Orbital Floor With Auricular Concha.

    PubMed

    Seven, Ergin; Tellioglu, Ali Teoman; Inozu, Emre; Ozakpinar, Hulda Rifat; Horoz, Ugur; Eryilmaz, Avni Tolga; Karamursel, Sebat

    2017-10-01

    Orbital floor fractures of varying sizes commonly occur after orbital injuries and remain a serious challenge. Serious complications of such fractures include enopthalmos, restriction of extraocular movement, and diplopia. There is a dearth of literature that can be applied widely, easily, and successfully in all such situations, and therefore there is no consensus on the treatment protocol of this pathology yet. Autogenous grafts and alloplastic and allogenic materials with a wide variety of advantages and disadvantages have been discussed. The value of preoperative and postoperative ophthalmological examination should be standard of care in all orbital fracture patients. An ideal reconstructed orbital floor fracture should accelerate the restoration of orbital function with acceptable cosmetic results. Management parameters of orbital fractures such as timing of surgery, incision type, and implant materials, though widely discussed, remain controversial. In this study, 55 patients with orbital floor fractures surgically reconstructed with conchal cartilage grafts between 2008 and 2014 were retrospectively evaluated. Complications and long-time follow-up visit results have been reported with clinical and radiographic findings. The aim of this study was to present the authors' clinical experiences of reconstruction of blow-out fractures with auricular conchal graft and to evaluate the other materials available for use.

  5. [Multi-wall orbital decompression for disfiguring proptosis in patients with mild or moderate thyroid eye disease].

    PubMed

    Wang, Y; Yang, N; Li, Y Y; Xiao, L H

    2017-02-11

    Objective: To evaluate the efficacy of orbital decompression by transconjunctival medial and inferior wall combined transpalpebral lateral wall for disfiguring proptosis with mild or moderate thyroid eye disease (TED). Methods: It is a retrospective case series study. The clinical data of 18 TED cases (28 orbits) between Dec 2013 and Dec 2015 at the Institute of Orbital Diseases of the General Hospital of the Armed Police were reviewed. All the patients underwent mulit-wall orbital decompression to relieve remarkable proptosis, widen eyelid fissure, and swollen eyelid. 1. Hertel value was 14-23 mm or over 2-7 mm than contralateral eye; 2.Orbitalpathy has been inactive with normal thyroid function for at least 6 months; 3.Orbital pressure is normal or (+). Clinical outcomes were recorded including best-corrected visual acuity, exophthalmometry, margin-to-central distance of upper and lower lids, diplopia, and CT scans before and 3 months after surgery. Results: The mean protosis of pre-and postoperation were (19.2±2.3) mm and (14.7±1.4) mm with mean reduction was (4.6±1.7) mm ( t= 14.08, P< 0.01). Margin-to-central distance of the upperlid of pre- and postoperation were (5.1±1.2) mm and (4.9±1.3) mm with mean reduction was (0.2±0.5) mm ( t= 1.73, P= 0.095). Margin-to-central distance of the lowerlid of pre-and postoperation were (5.9±0.9) mm and 4.3±0.7 mm with mean reduction was (1.6±0.8) mm ( t= 10.09, P< 0.01). The difference of bilateral exophthalmos after surgery is 0-2.5 mm (media n= 1 mm). None of the patients showed new-onset diplopia at primary gaze and two patient showed surrounding gaze diplopia postoperatively. Two patients with diplopia relieved after surgery ( Z= 743.00, P= 0.458). Conclusions: Transconjunctival and transpalpebral medial, inferior, and lateral walls decompression with a hidden incision was a controllable, safe, effective technique with minimal complications in relieving not only mild, moderate proptosis, but also retraction of

  6. A novel classification of frontal bone fractures: The prognostic significance of vertical fracture trajectory and skull base extension.

    PubMed

    Garg, Ravi K; Afifi, Ahmed M; Gassner, Jennifer; Hartman, Michael J; Leverson, Glen; King, Timothy W; Bentz, Michael L; Gentry, Lindell R

    2015-05-01

    The broad spectrum of frontal bone fractures, including those with orbital and skull base extension, is poorly understood. We propose a novel classification scheme for frontal bone fractures. Maxillofacial CT scans of trauma patients were reviewed over a five year period, and frontal bone fractures were classified: Type 1: Frontal sinus fracture without vertical extension. Type 2: Vertical fracture through the orbit without frontal sinus involvement. Type 3: Vertical fracture through the frontal sinus without orbit involvement. Type 4: Vertical fracture through the frontal sinus and ipsilateral orbit. Type 5: Vertical fracture through the frontal sinus and contralateral or bilateral orbits. We also identified the depth of skull base extension, and performed a chart review to identify associated complications. 149 frontal bone fractures, including 51 non-vertical frontal sinus (Type 1, 34.2%) and 98 vertical (Types 2-5, 65.8%) fractures were identified. Vertical fractures penetrated the middle or posterior cranial fossa significantly more often than non-vertical fractures (62.2 v. 15.7%, p = 0.0001) and had a significantly higher mortality rate (18.4 v. 0%, p < 0.05). Vertical fractures with frontal sinus and orbital extension, and fractures that penetrated the middle or posterior cranial fossa had the strongest association with intracranial injuries, optic neuropathy, disability, and death (p < 0.05). Vertical frontal bone fractures carry a worse prognosis than frontal bone fractures without a vertical pattern. In addition, vertical fractures with extension into the frontal sinus and orbit, or with extension into the middle or posterior cranial fossa have the highest complication rate and mortality. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  7. Orbitally shaken shallow fluid layers. II. An improved wall shear stress model

    NASA Astrophysics Data System (ADS)

    Alpresa, Paola; Sherwin, Spencer; Weinberg, Peter; van Reeuwijk, Maarten

    2018-03-01

    A new model for the analytical prediction of wall shear stress distributions at the base of orbitally shaken shallow fluid layers is developed. This model is a generalisation of the classical extended Stokes solution and will be referred to as the potential theory-Stokes model. The model is validated using a large set of numerical simulations covering a wide range of flow regimes representative of those used in laboratory experiments. It is demonstrated that the model is in much better agreement with the simulation data than the classical Stokes solution, improving the prediction in 63% of the studied cases. The central assumption of the model—which is to link the wall shear stress with the surface velocity—is shown to hold remarkably well over all regimes covered.

  8. Spin-orbit-torque-induced magnetic domain wall motion in Ta/CoFe nanowires with sloped perpendicular magnetic anisotropy.

    PubMed

    Zhang, Yue; Luo, Shijiang; Yang, Xiaofei; Yang, Chang

    2017-05-17

    In materials with the gradient of magnetic anisotropy, spin-orbit-torque-induced magnetization behaviour has attracted attention because of its intriguing scientific principle and potential application. Most of the magnetization behaviours microscopically originate from magnetic domain wall motion, which can be precisely depicted using the standard cooperative coordinate method (CCM). However, the domain wall motion in materials with the gradient of magnetic anisotropy using the CCM remains lack of investigation. In this paper, by adopting CCM, we established a set of equations to quantitatively depict the spin-orbit-torque-induced motion of domain walls in a Ta/CoFe nanotrack with weak Dzyaloshinskii-Moriya interaction and magnetic anisotropy gradient. The equations were solved numerically, and the solutions are similar to those of a micromagnetic simulation. The results indicate that the enhanced anisotropy along the track acts as a barrier to inhibit the motion of the domain wall. In contrast, the domain wall can be pushed to move in a direction with reduced anisotropy, with the velocity being accelerated by more than twice compared with that for the constant anisotropy case. This substantial velocity manipulation by anisotropy engineering is important in designing novel magnetic information devices with high reading speeds.

  9. Respiratory epithelial ingrowth and hemorrhage as late complications of orbital floor fracture repair with silicone sheet implant.

    PubMed

    Jones, David F; Wilson, Matthew W

    2008-01-01

    The authors present a unique case of rapidly progressive proptosis in a woman 23 years after repair of an orbital floor fracture. Clinical studies, surgical exploration, and pathology revealed a hemorrhagic cyst lined with respiratory epithelium surrounding her previously placed silicone implant.

  10. Changes in optical coherence tomography measurements after orbital wall decompression in dysthyroid optic neuropathy.

    PubMed

    Park, Kyung-Ah; Kim, Yoon-Duck; Woo, Kyung In

    2018-06-01

    The purpose of our study was to assess changes in peripapillary retinal nerve fiber layer (RNFL) thickness after orbital wall decompression in eyes with dysthyroid optic neuropathy (DON). We analyzed peripapillary optical coherence tomography (OCT) images (Cirrus HD-OCT) from controls and patients with DON before and 1 and 6 months after orbital wall decompression. There was no significant difference in mean preoperative peripapillary retinal nerve fiber layer thickness between eyes with DON and controls. The superior and inferior peripapillary RNFL thickness decreased significantly 1 month after decompression surgery compared to preoperative values (p = 0.043 and p = 0.022, respectively). The global average, superior, temporal, and inferior peripapillary RNFL thickness decreased significantly 6 months after decompression surgery compared to preoperative values (p = 0.015, p = 0.028, p = 0.009, and p = 0.006, respectively). Patients with greater preoperative inferior peripapillary RNFL thickness tended to have better postoperative visual acuity at the last visit (p = 0.024, OR = 0.926). Our data revealed a significant decrease in peripapillary RNFL thickness postoperatively after orbital decompression surgery in patients with DON. We also found that greater preoperative inferior peripapillary RNFL thickness was associated with better visual outcomes. We suggest that RNFL thickness can be used as a prognostic factor for DON before decompression surgery.

  11. Traumatic orbital CSF leak

    PubMed Central

    Borumandi, Farzad

    2013-01-01

    Compared to the cerebrospinalfluid (CSF) leak through the nose and ear, the orbital CSF leak is a rare and underreported condition following head trauma. We present the case of a 49-year-old woman with oedematous eyelid swelling and ecchymosis after a seemingly trivial fall onto the right orbit. Apart from the above, she was clinically unremarkable. The CT scan revealed a minimally displaced fracture of the orbital roof with no emphysema or intracranial bleeding. The fractured orbital roof in combination with the oedematous eyelid swelling raised the suspicion for orbital CSF leak. The MRI of the neurocranium demonstrated a small-sized CSF fistula extending from the anterior cranial fossa to the right orbit. The patient was treated conservatively and the lid swelling resolved completely after 5 days. Although rare, orbital CSF leak needs to be included in the differential diagnosis of periorbital swelling following orbital trauma. PMID:24323381

  12. What happens between pure hydraulic and buckling mechanisms of blowout fractures?

    PubMed

    Nagasao, Tomohisa; Miyamoto, Junpei; Shimizu, Yusuke; Jiang, Hua; Nakajima, Tatsuo

    2010-06-01

    The present study aims to evaluate how the ratio of the hydraulic and buckling mechanisms affects blowout fracture patterns, when these two mechanisms work simultaneously. Three-dimensional computer-aided-design (CAD)models were generated simulating ten skulls. To simulate impact, 1.2J was applied on the orbital region of these models in four patterns. Pattern 1: All the energy works to cause the hydraulic effect. Pattern 2: Two-thirds of the energy works to cause the hydraulic effect; one-third of the energy works to cause the buckling effect. Pattern 3: One-third of the energy works to cause the hydraulic effect; two-thirds of the energy works to cause the buckling effect. Pattern 4: The entire energy quantum works to cause the buckling effect. Using the finite element method, the regions where fractures were theoretically expected to occur were calculated and were compared between the four patterns. More fracture damage occurred for Pattern 1 than Pattern 2, and for Pattern 3 than for Pattern 4. The hydraulic and buckling mechanisms interact with one another. When these two mechanisms are combined, the orbital walls tend to develop serious fractures. Copyright (c) 2009 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  13. Fracture resistance of welded thick-walled high-pressure vessels in power plants. Report No. 2. Approach to evaluating static strength

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

    Gorynin, I.V.; Filatov, V.M.; Ignatov, V.A.

    1986-07-01

    The authors examine data on the effect of defects on the fracture resistance of high-pressure vessels and their models obtained within the framework of the HSST program. Results of internal-pressure tests of two types of vessels with a wall thickness of 152 mm made from forgings of steels SA508 and SA533, as well as small vessels with a wall thickness of 11.5 and 23mm made of steel SA533 are shown. The authors state that testing thick-walled welded high-pressure vessels and thin-walled vessels with surface defects of different sizes has demonstrated that there are substantial static-strength reserves in structures designed bymore » existing domestic and foreign standards on the strength of power-plant equipment. A correction was proposed for the presently used method of calculating the resistance of highpressure vessels to brittle fracture that allows for the dimensions of the defects in relation to the type of vessel, the manufacturing technology, and the method of inspection.« less

  14. Fracture patterns in the maxillofacial region: a four-year retrospective study

    PubMed Central

    2015-01-01

    Objectives The facial bones are the most noticeable area in the human body, and facial injuries can cause significant functional, aesthetic, and psychological complications. Continuous study of the patterns of facial bone fractures and changes in trends is helpful in the prevention and treatment of maxillofacial fractures. The purpose of the current clinico-statistical study is to investigate the pattern of facial fractures over a 4-year period. Materials and Methods A retrospective analysis of 1,824 fracture sites was carried out in 1,284 patients admitted to SMG-SNU Boramae Medical Center for facial bone fracture from January 2010 to December 2013. We evaluated the distributions of age/gender/season, fracture site, cause of injury, duration from injury to treatment, hospitalization period, and postoperative complications. Results The ratio of men to women was 3.2:1. Most fractures occurred in individuals aged between teens to 40s and were most prevalent at the middle and end of the month. Fractures occurred in the nasal bone (65.0%), orbital wall (29.2%), maxillary wall (15.3%), zygomatic arch (13.2%), zygomaticomaxillary complex (9.8%), mandibular symphysis (6.5%), mandibular angle (5.9%), mandibular condyle (4.9%), and mandibular body (1.9%). The most common etiologies were fall (32.5%) and assault (26.0%). The average duration of injury to treatment was 6 days, and the average hospitalization period was 5 days. Eighteen postoperative complications were observed in 17 patients, mainly infection and malocclusion in the mandible. Conclusion This study reflects the tendency for trauma in the Seoul metropolitan region because it analyzes all facial fracture patients who visited our hospital regardless of the specific department. Distinctively, in this study, midfacial fractures had a much higher incidence than mandible fractures. PMID:26734557

  15. Finite element method for analysis of stresses arising in the skull after external loading in cranio-orbital fractures.

    PubMed

    Wanyura, Hubert; Kowalczyk, Piotr; Bossak, Maciej; Samolczyk-Wanyura, Danuta; Stopa, Zygmunt

    2012-01-01

    The craniofacial skeleton remains not fully recognised as far as its mechanical resistance properties are concerned. Heretofore, the only available information on the mechanism of cranial bone fractures came from clinical observations, since the clinical evaluation in a living individual is practically impossible. It seems crucial to implement computer methods of virtual research into clinical practice. Such methods, which have long been used in the technical sciences, may either confirm or disprove previous observations. The aim of the study was to identify the areas of stress concentrations caused by external loads, which can lead to cranio-orbital fractures (COF), by the finite element method (FEM). For numerical analysis, a three-dimensional commercially available geometrical model of the skull was used which was imported into software of FEM. Computations were performed with ANSYS 12.1 Static Structural module. The loads were applied laterally to the frontal squama, the zygomatic process and partly to the upper orbital rim to locate dangerous concentration of stresses potentially resulting in COF. Changes in the area of force application revealed differences in values, quality and the extent of the stress distribution. Depending on the area of force application the following parameters would change: the value and area of stresses characteristic of COF. The distribution of stresses obtained in this study allowed definition of both the locations most vulnerable to fracture and sites from which fractures may originate or propagate.

  16. Growing skull fracture of the posterior cranial fossa and of the orbital roof.

    PubMed

    Caffo, M; Germanò, A; Caruso, G; Meli, F; Calisto, A; Tomasello, F

    2003-03-01

    Growing Skull Fractures (GSF) are rare complications of head trauma, primarily reported in infancy and early childhood. GSF are commonly located on calvaria, and rarely in other locations, including the skull base. In this study, we report two cases of GSF occurring in unusual locations. The first, a 8-month old girl, with a GSF of the suboccipital posterior fossa region, and the second, a 4-year old boy with a GSF of the right orbital roof. Both cases underwent operative treatment of the GSF, with microsurgical dissection and excision of the protruding gliotic brain tissue, watertight duraplasty and autologous bone cranial repair. The authors conducted a Medline search of the relevant English literature from 1966 to 2002. From the search, three cases of suboccipital posterior fossa region GSF and twelve series of orbital GSF, describing a total of 22 cases, have been found. A survey of the pathogenic mechanisms underlying this entity in these locations is reported. A review of suboccipital posterior fossa and orbital roof GSF cases, of nosological, ophthalmological and neurological data, neuroradiological and operative findings, and results of different treatment strategies are described.

  17. Patterns of Fracture and Tidal Stresses Due to Nonsynchronous Rotation: Implications for Fracturing on Europa

    NASA Technical Reports Server (NTRS)

    Parmentier, E. M.; Helfenstein, P.

    1985-01-01

    Global lineaments on Europa were interpreted as fractures in an icy crust. A variety of lineament types were identified, which appear to form a systematic pattern on the surface. For a synchronously rotating body, the patterns of fractures observed could be produced by a combination of stresses due to orbital recession, orbital eccentricity, and internal contraction. However, it was recently suggested that the forced eccentricity of Europa's orbit may result in nonsynchronous rotation. The hypothesis that fractures in a thin icy crust may have formed in response to stresses resulting from nonsynchronous rotation is studied.

  18. Does a minimal invasive approach reduce anterior chest wall numbness and postoperative pain in plate fixation of clavicle fractures?

    PubMed

    Beirer, Marc; Postl, Lukas; Crönlein, Moritz; Siebenlist, Sebastian; Huber-Wagner, Stefan; Braun, Karl F; Biberthaler, Peter; Kirchhoff, Chlodwig

    2015-05-28

    Fractures of the clavicle present very common injuries with a peak of incidence in young active patients. Recently published randomized clinical trials demonstrated an improved functional outcome and a lower rate of nonunions in comparison to non-operative treatment. Anterior chest wall numbness due to injury of the supraclavicular nerve and postoperative pain constitute common surgery related complications in plate fixation of displaced clavicle fractures. We recently developed a technique for mini open plating (MOP) of the clavicle to reduce postoperative numbness and pain. The purpose of this study was to analyze the size of anterior chest wall numbness and the intensity of postoperative pain in MOP in comparison to conventional open plating (COP) of clavicle fractures. 24 patients (mean age 38.2 ± 14.2 yrs.) with a displaced fracture of the clavicle (Orthopaedic Trauma Association B1.2-C1.2) surgically treated using a locking compression plate (LCP) were enrolled. 12 patients underwent MOP and another 12 patients COP. Anterior chest wall numbness was measured with a transparency grid on the second postoperative day and at the six months follow-up. Postoperative pain was evaluated using the Visual Analog Scale (VAS). Mean ratio of skin incision length to plate length was 0.61 ± 0.04 in the MOP group and 0.85 ± 0.06 in the COP group (p < 0.05). Mean ratio of the area of anterior chest wall numbness to plate length was postoperative 7.6 ± 5.9 (six months follow-up 4.7 ± 3.9) in the MOP group and 22.1 ± 19.1 (16.9 ± 14.1) in the COP group (p < 0.05). Mean VAS was 2.6 ± 1.4 points in the MOP group and 3.4 ± 1.6 points in the COP group (p = 0.20). In our study, MOP significantly reduced anterior chest wall numbness in comparison to a conventional open approach postoperative as well as at the six months follow-up. Postoperative pain tended to be lower in the MOP group, however this difference was not statistically significant. ClinicalTrials.gov NCT02247778

  19. Management of complex orbital fractures.

    PubMed

    Bhatti, N; Kanzaria, A; Huxham-Owen, N; Bridle, C; Holmes, S

    2016-09-01

    The treatment of orbital injuries has evolved considerably over the last two decades. We describe strategies involved in the emergency management of orbital injuries, the use of imaging, preformed and customised materials for reconstruction, and endoscopic techniques. Copyright © 2016 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  20. The advantages of advanced computer-assisted diagnostics and three-dimensional preoperative planning on implant position in orbital reconstruction.

    PubMed

    Jansen, Jesper; Schreurs, Ruud; Dubois, Leander; Maal, Thomas J J; Gooris, Peter J J; Becking, Alfred G

    2018-04-01

    Advanced three-dimensional (3D) diagnostics and preoperative planning are the first steps in computer-assisted surgery (CAS). They are an integral part of the workflow, and allow the surgeon to adequately assess the fracture and to perform virtual surgery to find the optimal implant position. The goal of this study was to evaluate the accuracy and predictability of 3D diagnostics and preoperative virtual planning without intraoperative navigation in orbital reconstruction. In 10 cadaveric heads, 19 complex orbital fractures were created. First, all fractures were reconstructed without preoperative planning (control group) and at a later stage the reconstructions were repeated with the help of preoperative planning. Preformed titanium mesh plates were used for the reconstructions by two experienced oral and maxillofacial surgeons. The preoperative virtual planning was easily accessible for the surgeon during the reconstruction. Computed tomographic scans were obtained before and after creation of the orbital fractures and postoperatively. Using a paired t-test, implant positioning accuracy (translation and rotations) of both groups were evaluated by comparing the planned implant position with the position of the implant on the postoperative scan. Implant position improved significantly (P < 0.05) for translation, yaw and roll in the group with preoperative planning (Table 1). Pitch did not improve significantly (P = 0.78). The use of 3D diagnostics and preoperative planning without navigation in complex orbital wall fractures has a positive effect on implant position. This is due to a better assessment of the fracture, the possibility of virtual surgery and because the planning can be used as a virtual guide intraoperatively. The surgeon has more control in positioning the implant in relation to the rim and other bony landmarks. Copyright © 2018 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  1. Pediatric maxillofacial fractures.

    PubMed

    Spring, P M; Cote, D N

    1996-05-01

    Maxillofacial trauma in the pediatric population is a relatively infrequent occurrence. Studies have demonstrated consistently that 5% of all facial fractures occur in children. The low percentage of facial fractures in this age group has been attributed, in part, to the lack of full pneumatization of the sinuses until later in childhood. Review of the literature indicates that boys are more commonly affected than girls and that the majority of pediatric facial fractures occur in children between 6 and 12 years of age. Motor vehicle accidents, falls, and blunt trauma are responsible for the largest number of pediatric facial fractures. The most common site of facial fracture is the nose and dentoalveolan complex, followed by the mandible, orbit, and midface in most pediatric cohorts. Management of the mandible is often conservative owing to the high percentage of isolated condylar fractures in children. Open reduction and internal fixation of pediatric facial fractures is indicated in complex mandible, midface, and orbital fractures. The effect of rigid fixation on facial skeleton growth is not completely understood.

  2. Vibrational modes of hydraulic fractures: Inference of fracture geometry from resonant frequencies and attenuation

    NASA Astrophysics Data System (ADS)

    Lipovsky, Bradley P.; Dunham, Eric M.

    2015-02-01

    Oscillatory seismic signals arising from resonant vibrations of hydraulic fractures are observed in many geologic systems, including volcanoes, glaciers and ice sheets, and hydrocarbon and geothermal reservoirs. To better quantify the physical dimensions of fluid-filled cracks and properties of the fluids within them, we study wave motion along a thin hydraulic fracture waveguide. We present a linearized analysis, valid at wavelengths greater than the fracture aperture, that accounts for quasi-static elastic deformation of the fracture walls, as well as fluid viscosity, inertia, and compressibility. In the long-wavelength limit, anomalously dispersed guided waves known as crack or Krauklis waves propagate with restoring force from fracture wall elasticity. At shorter wavelengths, the waves become sound waves within the fluid channel. Wave attenuation in our model is due to fluid viscosity, rather than seismic radiation from crack tips or fracture wall roughness. We characterize viscous damping at both low frequencies, where the flow is always fully developed, and at high frequencies, where the flow has a nearly constant velocity profile away from viscous boundary layers near the fracture walls. Most observable seismic signals from resonating fractures likely arise in the boundary layer crack wave limit, where fluid-solid coupling is pronounced and attenuation is minimal. We present a method to estimate the aperture and length of a resonating hydraulic fracture using both the seismically observed quality factor and characteristic frequency. Finally, we develop scaling relations between seismic moment and characteristic frequency that might be useful when interpreting the statistics of hydraulic fracture events.

  3. Inter-wall bridging induced peeling of multi-walled carbon nanotubes during tensile failure in aluminum matrix composites.

    PubMed

    Chen, Biao; Li, Shufeng; Imai, Hisashi; Umeda, Junko; Takahashi, Makoto; Kondoh, Katsuyoshi

    2015-02-01

    In situ scanning electron microscopy (SEM) observation of a tensile test was performed to investigate the fracturing behavior of multi-walled carbon nanotubes (MWCNTs) in powder metallurgy Al matrix composites. A multiple peeling phenomenon during MWCNT fracturing was clearly observed. Its formation mechanism and resultant effect on the composite strength were examined. Through transition electron microscopy characterizations, it was observed that defective structures like inter-wall bridges cross-linked adjacent walls of MWCNTs. This structure was helpful to improve the inter-wall bonding conditions, leading to the effective load transfer between walls and resultant peeling behaviors of MWCNTs. These results might provide new understandings of the fracturing mechanisms of carbon nanotube reinforcements for designing high-performance nanocomposites. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Dynamics of chiral domain wall under the spin-orbit torques in heavy metal/ferromagnet bilayers with in-plane anisotropy

    NASA Astrophysics Data System (ADS)

    Yan, Han; He, Peng-Bin; Cai, Meng-Qiu; Li, Zai-Dong

    2017-11-01

    The dynamics of domain wall driven by the spin-orbit torques is theoretically studied in the heavy metal/ferromagnet bilayer with Dzyaloshinskii-Moriya interaction (DMI) and in-plane magnetic anisotropy. Based on the Walker profile, we infer that DMI has a selectivity for the chirality of head-to-head (tail-to-tail) static wall. By analyzing the dynamic equations obtained from the collective coordinates methods, we find that there exists a switching or a hysteresis of the polarity of wall in the low-current regime. In the presence of DMI, the wall can keep sustained propagation which velocity saturates for high current and is proportional to the strength of DMI. Furthermore, the DMI makes the adjacent walls possess the same chirality and move in the same direction.

  5. Spiderweb-like Fractures in Occator Crater

    NASA Image and Video Library

    2018-01-30

    This image shows a complex set of fractures found in the southwestern region of the floor of Occator Crater on Ceres. In this picture, north is at the top. The two intersecting fracture systems (roughly northwest-southeast and southwest-northeast) are part of a larger fault network that extends across Occator's floor. These fractures have been interpreted as evidence that material came up from below and formed a dome shape, as if a piston was pushing Occator's floor from beneath the surface. This may be due to the upwelling of material coming from Ceres' deep interior. An alternative hypothesis is that the deformation is due to volume changes inside a reservoir of icy magma in the shallow subsurface that is in the process of freezing, similar to the change in volume that a bottle of water experiences when put in a freezer. Another set of fractures can be seen parallel to the southwestern wall and is not connected to the Occator fracture network. Dawn took this image during its extended mission on August 17, 2016, from its low-altitude mapping orbit, at a distance of about 240 miles (385 kilometers) above the surface. The image resolution is 120 feet (35 meters) per pixel. The center coordinates are 16 degrees north in latitude and 237 east in longitude. https://photojournal.jpl.nasa.gov/catalog/PIA22091

  6. Diagnostic tools in maxillofacial fractures: Is there really a need of three-dimensional computed tomography?

    PubMed

    Shah, Sheerin; Uppal, Sanjeev K; Mittal, Rajinder K; Garg, Ramneesh; Saggar, Kavita; Dhawan, Rishi

    2016-01-01

    Because of its functional and cosmetic importance, facial injuries, especially bony fractures are clinically very significant. Missed and maltreated fractures might result in malocclusion and disfigurement of the face, thus making accurate diagnosis of the fracture very essential. In earlier times, conventional radiography along with clinical examination played a major role in diagnosis of maxillofacial fractures. However, it was noted that the overlapping nature of bones and the inability to visualise soft tissue swelling and fracture displacement, especially in face, makes radiography less reliable and useful. Computed tomography (CT), also called as X-ray computed radiography, has helped in solving this problem. This clinical study is to compare three-dimensional (3D) CT reconstruction with conventional radiography in evaluating the maxillofacial fractures preoperatively and effecting the surgical management, accordingly. Fifty patients, with suspected maxillofacial fractures on clinical examination, were subjected to conventional radiography and CT face with 3D reconstruction. The number and site of fractures in zygoma, maxilla, mandible and nose, detected by both the methods, were enumerated and compared. The final bearing of these additional fractures, on the management protocol, was analysed. CT proved superior to conventional radiography in diagnosing additional number of fractures in zygoma, maxilla, mandible (subcondylar) and nasal bone. Coronal and axial images were found to be significantly more diagnostic in fracture sites such as zygomaticomaxillary complex, orbital floor, arch, lateral maxillary wall and anterior maxillary wall. 3D images gave an inside out picture of the actual sites of fractures. It acted as mind's eye for pre-operative planning and intra-operative execution of surgery. Better surgical treatment could be given to 33% of the cases because of better diagnostic ability of CT.

  7. Is there more to the clinical outcome in posttraumatic reconstruction of the inferior and medial orbital walls than accuracy of implant placement and implant surface contouring? A prospective multicenter study to identify predictors of clinical outcome.

    PubMed

    Zimmerer, Rüdiger M; Gellrich, Nils-Claudius; von Bülow, Sophie; Strong, Edward Bradley; Ellis, Edward; Wagner, Maximilian E H; Sanchez Aniceto, Gregorio; Schramm, Alexander; Grant, Michael P; Thiam Chye, Lim; Rivero Calle, Alvaro; Wilde, Frank; Perez, Daniel; Bittermann, Gido; Mahoney, Nicholas R; Redondo Alamillos, Marta; Bašić, Joanna; Metzger, Marc; Rasse, Michael; Dittman, Jan; Rometsch, Elke; Espinoza, Kathrin; Hesse, Ronny; Cornelius, Carl-Peter

    2018-04-01

    Reconstruction of orbital wall fractures is demanding and has improved dramatically with the implementation of new technologies. True-to-original accuracy of reconstruction has been deemed essential for good clinical outcome, and reasons for unfavorable clinical outcome have been researched extensively. However, no detailed analysis on the influence of plate position and surface contour on clinical outcome has yet been published. Data from a previous study were used for an ad-hoc analysis to identify predictors for unfavorable outcome, defined as diplopia or differences in globe height and/or globe projection of >2 mm. Presumed predictors were implant surface contour, aberrant implant dimension or position, accuracy of reconstructed orbital volume, and anatomical fracture topography according to the current AO classification. Neither in univariable nor in multivariable regression models were unfavorable clinical outcomes associated with any of the presumed radiological predictors, and no association of the type of implant, i.e., standard preformed, CAD-based individualized and non-CAD-based individualized with its surface contour could be shown. These data suggest that the influence of accurate mechanical reconstruction on clinical outcomes may be less predictable than previously believed, while the role of soft-tissue-related factors may have been underestimated. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  8. Ultralow-dose computed tomography imaging for surgery of midfacial and orbital fractures using ASIR and MBIR.

    PubMed

    Widmann, G; Dalla Torre, D; Hoermann, R; Schullian, P; Gassner, E M; Bale, R; Puelacher, W

    2015-04-01

    The influence of dose reductions on diagnostic quality using a series of high-resolution ultralow-dose computed tomography (CT) scans for computer-assisted planning and surgery including the most recent iterative reconstruction algorithms was evaluated and compared with the fracture detectability of a standard cranial emergency protocol. A human cadaver head including the mandible was artificially prepared with midfacial and orbital fractures and scanned using a 64-multislice CT scanner. The CT dose index volume (CTDIvol) and effective doses were calculated using application software. Noise was evaluated as the standard deviation in Hounsfield units within an identical region of interest in the posterior fossa. Diagnostic quality was assessed by consensus reading of a craniomaxillofacial surgeon and radiologist. Compared with the emergency protocol at CTDIvol 35.3 mGy and effective dose 3.6 mSv, low-dose protocols down to CTDIvol 1.0 mGy and 0.1 mSv (97% dose reduction) may be sufficient for the diagnosis of dislocated craniofacial fractures. Non-dislocated fractures may be detected at CTDIvol 2.6 mGy and 0.3 mSv (93% dose reduction). Adaptive statistical iterative reconstruction (ASIR) 50 and 100 reduced average noise by 30% and 56%, and model-based iterative reconstruction (MBIR) by 93%. However, the detection rate of fractures could not be improved due to smoothing effects. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  9. Advances in the management of orbital fractures.

    PubMed

    Nguyen, P N; Sullivan, P

    1992-01-01

    Great progress has been made in both the basic science and the clinical knowledge base used in orbital reconstruction. With this, increasing complex orbital reconstructive problems are better managed. The diagnosis, treatment plan, and the actual reconstruction have evolved to a higher level. Several areas of progress are of note: the greater appreciation of the intimate relation between the bony orbit's shape and the position of the globe; application of computer technology in orbital injuries; effect of rigid fixation on autogenous and alloplastic graft; and the use of advanced biocompatible synthetic materials in orbital reconstruction. Although this progress has great impact on treatment of orbital injuries, there are many unanswered challenges in the treatment of the fragile frame of the window to the human soul.

  10. Sudden transient complete loss of vision caused by nose blowing after a fracture of the orbital floor.

    PubMed

    Harmer, S G; Ethunandan, M; Zaki, G A; Brennan, P A

    2007-03-01

    A 52-year-old man was being attended to in a hospital for a fracture of the right zygoma and orbital floor, after being struck on the right upper face. After blowing his nose, he immediately lost vision in the right eye, and an urgent CT scan showed extensive retrobulbar air. Vision was regained within an hour. The management of this rare condition is discussed.

  11. Current induced domain wall dynamics in the presence of spin orbit torques

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

    Boulle, O., E-mail: Olivier.boulle@cea.fr; Buda-Prejbeanu, L. D.; Jué, E.

    2014-05-07

    Current induced domain wall (DW) motion in perpendicularly magnetized nanostripes in the presence of spin orbit torques is studied. We show using micromagnetic simulations that the direction of the current induced DW motion and the associated DW velocity depend on the relative values of the field like torque (FLT) and the Slonczewski like torques (SLT). The results are well explained by a collective coordinate model which is used to draw a phase diagram of the DW dynamics as a function of the FLT and the SLT. We show that a large increase in the DW velocity can be reached bymore » a proper tuning of both torques.« less

  12. Examination of Relationship Between Photonic Signatures and Fracture Strength of Fused Silica Used in Orbiter Windows

    NASA Technical Reports Server (NTRS)

    Yost, William T.; Cramer, K. Elliott; Estes, Linda R.; Salem, Jonathan A.; Lankford, James, Jr.; Lesniak, Jon

    2011-01-01

    A commercially available grey-field polariscope (GFP) instrument for photoelastic examination is used to assess impact damage inflicted upon the outermost pane of the orbiter windows. Four categories of damage: hyper-velocity impacts that occur during space-flight (HVI); hypervelocity impacts artificially made at the Hypervelocity Impact Technology Facility (HIT-F); impacts made by larger objects falling onto the pane surface to simulate dropped items on the window during service/storage of vehicle (Bruises); and light scratches from dull objects designed to mimic those that might occur by dragging a dull object across the glass surface (Chatter Checks) are examined. The damage sites are cored from fused silica window carcasses, examined with the GFP and other methodologies, and broken using the ASTM Standard C1499-09 to measure the fracture strength. A correlation is made between the fracture strength and damage-site measurements including geometrical measurements and GFP measurements of photoelastic retardation (stress patterns) surrounding the damage sites. An analytical damage model to predict fracture strength from photoelastic retardation measurements is presented and compared with experimental results.

  13. The globe and orbit in Laron syndrome.

    PubMed

    Kornreich, L; Konen, O; Lilos, P; Laron, Z

    2011-09-01

    Patients with LS have an inborn growth hormone resistance, resulting in failure to generate IGF-1. The purpose of this study was to evaluate the size of the eye and orbit in LS. We retrospectively reviewed the MR imaging of the brain in 9 patients with LS for the following parameters: axial diameter of the globe, interzygomatic distance, perpendicular distance from the interzygomatic line to margins of the globe, medial-to-lateral diameter of the orbit at the anterior orbital rim, distance from the anterior orbital rim to the anterior globe, maximal distance between the medial walls of the orbits, lateral orbital wall angle, lateral orbital wall length, and mediolateral thickness of the intraorbital fat in the most cranial image of the orbit. All measurements were made bilaterally. Twenty patients referred for MR imaging for unrelated reasons served as control subjects. Compared with the control group, the patients with LS had a significantly smaller maximal globe diameter and shallower but wider orbits due to a shorter lateral wall, a smaller medial distance between the orbits, and a larger angle of the orbit. The ratio between the most anterior orbital diameter and the globe was greater than that in controls. The position of the globe was more anterior in relation to the interzygomatic line. Shallow and wide orbits and small globes relative to orbital size are seen in LS and may be secondary to IGF-1 deficiency.

  14. Facial Fractures: Pearls and Perspectives.

    PubMed

    Chaudhry, Obaid; Isakson, Matthew; Franklin, Adam; Maqusi, Suhair; El Amm, Christian

    2018-05-01

    After studying this article, the participant should be able to: 1. Describe the A-frame configuration of anterior facial buttresses, recognize the importance of restoring anterior projection in frontal sinus fractures, and describe an alternative design and donor site of pericranial flaps in frontal sinus fractures. 2. Describe the symptoms and cause of pseudo-Brown syndrome, describe the anatomy and placement of a buttress-spanning plate in nasoorbitoethmoid fractures, and identify appropriate nasal support alternatives for nasoorbitoethmoid fractures. 3. Describe the benefits and disadvantages of different lower lid approaches to the orbital floor and inferior rim, identify late exophthalmos as a complication of reconstructing the orbital floor with nonporous alloplast, and select implant type and size for correction of secondary enophthalmos. 4. Describe closed reduction of low-energy zygomatic body fractures with the Gillies approach and identify situations where internal fixation may be unnecessary, identify situations where plating the inferior orbital rim may be avoided, and select fixation points for osteosynthesis of uncomplicated displaced zygomatic fractures. 5. Understand indications and complications of use for intermaxillary screw systems, understand sequencing panfacial fractures, describe the sulcular approach to mandible fractures, and describe principles and techniques of facial reconstruction after self-inflicted firearm injuries. Treating patients with facial trauma remains a core component of plastic surgery and a significant part of the value of a plastic surgeon to a health system.

  15. Diagnostic tools in maxillofacial fractures: Is there really a need of three-dimensional computed tomography?

    PubMed Central

    Shah, Sheerin; Uppal, Sanjeev K.; Mittal, Rajinder K.; Garg, Ramneesh; Saggar, Kavita; Dhawan, Rishi

    2016-01-01

    Introduction: Because of its functional and cosmetic importance, facial injuries, especially bony fractures are clinically very significant. Missed and maltreated fractures might result in malocclusion and disfigurement of the face, thus making accurate diagnosis of the fracture very essential. In earlier times, conventional radiography along with clinical examination played a major role in diagnosis of maxillofacial fractures. However, it was noted that the overlapping nature of bones and the inability to visualise soft tissue swelling and fracture displacement, especially in face, makes radiography less reliable and useful. Computed tomography (CT), also called as X-ray computed radiography, has helped in solving this problem. This clinical study is to compare three-dimensional (3D) CT reconstruction with conventional radiography in evaluating the maxillofacial fractures preoperatively and effecting the surgical management, accordingly. Materials and Methods: Fifty patients, with suspected maxillofacial fractures on clinical examination, were subjected to conventional radiography and CT face with 3D reconstruction. The number and site of fractures in zygoma, maxilla, mandible and nose, detected by both the methods, were enumerated and compared. The final bearing of these additional fractures, on the management protocol, was analysed. Results: CT proved superior to conventional radiography in diagnosing additional number of fractures in zygoma, maxilla, mandible (subcondylar) and nasal bone. Coronal and axial images were found to be significantly more diagnostic in fracture sites such as zygomaticomaxillary complex, orbital floor, arch, lateral maxillary wall and anterior maxillary wall. Conclusion: 3D images gave an inside out picture of the actual sites of fractures. It acted as mind's eye for pre-operative planning and intra-operative execution of surgery. Better surgical treatment could be given to 33% of the cases because of better diagnostic ability of CT

  16. Bilateral orbital bone infarction in sickle-cell disease.

    PubMed

    Ghafouri, Roya H; Lee, Irene; Freitag, Suzanne K; Pira, Tony N

    2011-01-01

    This is a case of a 2-year-old boy with sickle cell disease who presented with bilateral eyelid swelling, limited extraocular motility, and lateral subperiosteal fluid collection associated with bilateral lateral orbital wall infarctions on MRI. The patient was managed medically with intravenous fluids, analgesics, broad-spectrum antibiotics, systemic steroids, and clinically improved. Patients with sickle cell disease are susceptible to infarction of the orbital bones during vaso-occlusive crises. Orbital wall infarction can lead to acute proptosis and restricted extraocular motility. Orbital wall infarction should be considered in sickle cell patients with orbital diseases so that appropriate treatment can be instituted promptly to prevent the serious sequelae of orbital compression syndrome.

  17. Quartz c-axis orientation patterns in fracture cement as a measure of fracture opening rate and a validation tool for fracture pattern models

    DOE PAGES

    Ukar, Estibalitz; Laubach, Stephen E.; Marrett, Randall

    2016-03-09

    Here, we evaluate a published model for crystal growth patterns in quartz cement in sandstone fractures by comparing crystal fracture-spanning predictions to quartz c-axis orientation distributions measured by electron backscatter diffraction (EBSD) of spanning quartz deposits. Samples from eight subvertical opening-mode fractures in four sandstone formations, the Jurassic– Cretaceous Nikanassin Formation, northwestern Alberta Foothills (Canada), Cretaceous Mesaverde Group (USA; Cozzette Sandstone Member of the Iles Formation), Piceance Basin, Colorado (USA), and upper Jurassic–lower Cretaceous Cotton Valley Group (Taylor sandstone) and overlying Travis Peak Formation, east Texas, have similar quartzose composition and grain size but contain fractures with different temperature historiesmore » and opening rates based on fluid inclusion assemblages and burial history. Spherical statistical analysis shows that, in agreement with model predictions, bridging crystals have a preferred orientation with c-axis orientations at a high angle to fracture walls. The second form of validation is for spanning potential that depends on the size of cut substrate grains. Using measured cut substrate grain sizes and c-axis orientations of spanning bridges, we calculated the required orientation for the smallest cut grain to span the maximum gap size and the required orientation of the crystal with the least spanning potential to form overgrowths that span across maximum measured gap sizes. We find that within a 10° error all spanning crystals conform to model predictions. Using crystals with the lowest spanning potential based on crystallographic orientation (c-axis parallel to fracture wall) and a temperature range for fracture opening measured from fluid inclusion assemblages, we calculate maximum fracture opening rates that allow crystals to span. These rates are comparable to those derived independently from fracture temperature histories based on burial history and

  18. Quartz c-axis orientation patterns in fracture cement as a measure of fracture opening rate and a validation tool for fracture pattern models

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

    Ukar, Estibalitz; Laubach, Stephen E.; Marrett, Randall

    Here, we evaluate a published model for crystal growth patterns in quartz cement in sandstone fractures by comparing crystal fracture-spanning predictions to quartz c-axis orientation distributions measured by electron backscatter diffraction (EBSD) of spanning quartz deposits. Samples from eight subvertical opening-mode fractures in four sandstone formations, the Jurassic– Cretaceous Nikanassin Formation, northwestern Alberta Foothills (Canada), Cretaceous Mesaverde Group (USA; Cozzette Sandstone Member of the Iles Formation), Piceance Basin, Colorado (USA), and upper Jurassic–lower Cretaceous Cotton Valley Group (Taylor sandstone) and overlying Travis Peak Formation, east Texas, have similar quartzose composition and grain size but contain fractures with different temperature historiesmore » and opening rates based on fluid inclusion assemblages and burial history. Spherical statistical analysis shows that, in agreement with model predictions, bridging crystals have a preferred orientation with c-axis orientations at a high angle to fracture walls. The second form of validation is for spanning potential that depends on the size of cut substrate grains. Using measured cut substrate grain sizes and c-axis orientations of spanning bridges, we calculated the required orientation for the smallest cut grain to span the maximum gap size and the required orientation of the crystal with the least spanning potential to form overgrowths that span across maximum measured gap sizes. We find that within a 10° error all spanning crystals conform to model predictions. Using crystals with the lowest spanning potential based on crystallographic orientation (c-axis parallel to fracture wall) and a temperature range for fracture opening measured from fluid inclusion assemblages, we calculate maximum fracture opening rates that allow crystals to span. These rates are comparable to those derived independently from fracture temperature histories based on burial history and

  19. Bicuspid Axial Wall Height Effect on CAD/CAM Crown Fracture Mode on Preparations Containing Advanced Total Occlusal Convergence.

    PubMed

    Miller, Matthew; DuVall, Nicholas; Brewster, John; Wajdowicz, Michael N; Harris, Ashley; Roberts, Howard W

    2018-02-18

    To evaluate bicuspid axial wall height effect on the fracture mode of adhesively luted, all-ceramic CAD/CAM crowns with a 20° total occlusal convergence (TOC). Recently extracted premolars were randomly divided into 4 groups (n = 12) with all-ceramic crown preparations accomplished using a high-speed handpiece inserted into a milling device. Specimens were prepared containing occlusogingival axial wall heights of 3, 2, and 1 mm as well as a group containing a flat preparation surface with no axial wall height. All preparations contained a 20° TOC. Completed preparation surface area was determined, and preparation features confirmed using a digital measuring microscope. Scanned preparations (CEREC) were fitted with milled and crystallized lithium disilicate full coverage restorations and luted with a self-etching adhesive resin cement after hydrofluoric acid etching and silanation. All manufacturer recommendations were followed. Specimens were stored at 37°C/98% humidity for 24 hours. Specimens were tested to failure at a 45° angle to the long axis of the tooth root on a universal testing machine. Failure load was converted to MPa using the available bonding surface area with mean data analyzed using Kruskal-Wallis/Dunn's (p = 0.05) RESULTS: The 3 mm preparation height specimens were similar to the 2 mm specimens, and both demonstrated significantly stronger failure load than the 1 mm axial wall height and flat preparation specimens. The flat preparation and 1 mm axial wall height specimens all failed adhesively, while the 2 mm and 3 mm specimens failed largely due to tooth fracture. Further evidence is provided that CAD/CAM adhesive techniques may compensate for less than ideal preparation features. Under the conditions of this study, bicuspid preparations with a 20° TOC restored with adhesively luted, CAD/CAM e.max CAD crowns require at least 2 mm of axial wall height, but further planned fatigue studies are necessary before definitive recommendations can be

  20. Fractured Mounds in Elysium Planitia

    NASA Image and Video Library

    2010-10-15

    This observation from NASA Mars Reconnaissance Orbiter shows fractured mounds on the southern edge of Elysium Planitia. The fractures that crisscross their surfaces are probably composed of solidified lava.

  1. Rigid fixation of facial fractures in children.

    PubMed

    Koltai, P J; Rabkin, D; Hoehn, J

    1995-01-01

    This article presents a retrospective analysis of a selective use of rigid fixation among 62 children with facial fractures, treated at a Level I trauma center over a 5-year period (1986-1991). There were 21 mandible fractures, 11 orbital fractures, 11 zygomaticomalar complex fractures, 7 nasal fractures, 5 maxillary fractures, 3 pan-facial fractures, 2 nasal-orbital-ethmoidal complex fractures, and 2 frontal sinus fractures. Only 18 children had rigid fixation of their injuries. Complications of Le Fort upper facial fractures repaired with rigid fixation involved perioperative sinusitis; one case required oral antibiotics, the other ethmoidectomy and maxillary antrostomy. One child with a Le Fort fracture had delayed exposure of a zygomaticomalar buttress plate, which required surgical removal. Permanent enophthalmos occurred in two children with Le Fort fractures. The authors conclude that traditional conservative management is appropriate in most cases. However, in children aged 13 and older with mandible fractures and children with complex mid- and upper facial fractures, a judicious use of rigid fixation has advantages over the traditional techniques.

  2. Analytical Modeling of Pressure Wall Hole Size and Maximum Tip-to-Tip Crack Length for Perforating Normal and Oblique Orbital Debris Impacts

    NASA Technical Reports Server (NTRS)

    Schonberg, William P.; Mohamed, Essam

    1997-01-01

    This report presents the results of a study whose objective was to develop first-principles-based models of hole size and maximum tip-to-tip crack length for a spacecraft module pressure wall that has been perforated in an orbital debris particle impact. The hole size and crack length models are developed by sequentially characterizing the phenomena comprising the orbital debris impact event, including the initial impact, the creation and motion of a debris cloud within the dual-wall system, the impact of the debris cloud on the pressure wall, the deformation of the pressure wall due to debris cloud impact loading prior to crack formation, pressure wall crack initiation, propagation, and arrest, and finally pressure wall deformation following crack initiation and growth. The model development has been accomplished through the application of elementary shock physics and thermodynamic theory, as well as the principles of mass, momentum, and energy conservation. The predictions of the model developed herein are compared against the predictions of empirically-based equations for hole diameters and maximum tip-to-tip crack length for three International Space Station wall configurations. The ISS wall systems considered are the baseline U.S. Lab Cylinder, the enhanced U.S. Lab Cylinder, and the U.S. Lab Endcone. The empirical predictor equations were derived from experimentally obtained hole diameters and crack length data. The original model predictions did not compare favorably with the experimental data, especially for cases in which pressure wall petalling did not occur. Several modifications were made to the original model to bring its predictions closer in line with the experimental results. Following the adjustment of several empirical constants, the predictions of the modified analytical model were in much closer agreement with the experimental results.

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

    Zilkha, A.

    Computed tomographic (CT) findings in four patients with isolated blow-out fracture of the medial orbital wall are reported. CT delineated the fracture site and its extent in each case, and clearly demonstrated medial rectus muscle entrapment in two. This was confirmed by surgery. CT was found superior to polytomography and proved to be the best radiologic means for the diagnosis of medial orbital wall fracture and muscle entrapment.

  4. Altered disc pressure profile after an osteoporotic vertebral fracture is a risk factor for adjacent vertebral body fracture

    PubMed Central

    Tzermiadianos, Michael N.; Renner, Susan M.; Phillips, Frank M.; Hadjipavlou, Alexander G.; Zindrick, Michael R.; Havey, Robert M.; Voronov, Michael

    2008-01-01

    This study investigated the effect of endplate deformity after an osteoporotic vertebral fracture in increasing the risk for adjacent vertebral fractures. Eight human lower thoracic or thoracolumbar specimens, each consisting of five vertebrae were used. To selectively fracture one of the endplates of the middle VB of each specimen a void was created under the target endplate and the specimen was flexed and compressed until failure. The fractured vertebra was subjected to spinal extension under 150 N preload that restored the anterior wall height and vertebral kyphosis, while the fractured endplate remained significantly depressed. The VB was filled with cement to stabilize the fracture, after complete evacuation of its trabecular content to ensure similar cement distribution under both the endplates. Specimens were tested in flexion-extension under 400 N preload while pressure in the discs and strain at the anterior wall of the adjacent vertebrae were recorded. Disc pressure in the intact specimens increased during flexion by 26 ± 14%. After cementation, disc pressure increased during flexion by 15 ± 11% in the discs with un-fractured endplates, while decreased by 19 ± 26.7% in the discs with the fractured endplates. During flexion, the compressive strain at the anterior wall of the vertebra next to the fractured endplate increased by 94 ± 23% compared to intact status (p < 0.05), while it did not significantly change at the vertebra next to the un-fractured endplate (18.2 ± 7.1%, p > 0.05). Subsequent flexion with compression to failure resulted in adjacent fracture close to the fractured endplate in six specimens and in a non-adjacent fracture in one specimen, while one specimen had no adjacent fractures. Depression of the fractured endplate alters the pressure profile of the damaged disc resulting in increased compressive loading of the anterior wall of adjacent vertebra that predisposes it to wedge fracture. This data suggests that

  5. A Novel Method of Orbital Floor Reconstruction Using Virtual Planning, 3-Dimensional Printing, and Autologous Bone.

    PubMed

    Vehmeijer, Maarten; van Eijnatten, Maureen; Liberton, Niels; Wolff, Jan

    2016-08-01

    Fractures of the orbital floor are often a result of traffic accidents or interpersonal violence. To date, numerous materials and methods have been used to reconstruct the orbital floor. However, simple and cost-effective 3-dimensional (3D) printing technologies for the treatment of orbital floor fractures are still sought. This study describes a simple, precise, cost-effective method of treating orbital fractures using 3D printing technologies in combination with autologous bone. Enophthalmos and diplopia developed in a 64-year-old female patient with an orbital floor fracture. A virtual 3D model of the fracture site was generated from computed tomography images of the patient. The fracture was virtually closed using spline interpolation. Furthermore, a virtual individualized mold of the defect site was created, which was manufactured using an inkjet printer. The tangible mold was subsequently used during surgery to sculpture an individualized autologous orbital floor implant. Virtual reconstruction of the orbital floor and the resulting mold enhanced the overall accuracy and efficiency of the surgical procedure. The sculptured autologous orbital floor implant showed an excellent fit in vivo. The combination of virtual planning and 3D printing offers an accurate and cost-effective treatment method for orbital floor fractures. Copyright © 2016 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  6. Acetabular fractures: anatomic and clinical considerations.

    PubMed

    Lawrence, David A; Menn, Kirsten; Baumgaertner, Michael; Haims, Andrew H

    2013-09-01

    Classifying acetabular fractures can be an intimidating topic. However, it is helpful to remember that there are only three basic types of acetabular fractures: column fractures, transverse fractures, and wall fractures. Within this framework, acetabular fractures are classified into two broad categories: elementary or associated fractures. We will review the osseous anatomy of the pelvis and provide systematic approaches for reviewing both radiographs and CT scans to effectively evaluate the acetabulum. Although acetabular fracture classification may seem intimidating, the descriptions and distinctions discussed and shown in this article hopefully make the topic simpler to understand. Approach the task by recalling that there are only three basic types of acetabular fractures: column fractures (coronally oriented on CT images), transverse fractures (sagittally oriented on CT images), and wall fractures (obliquely oriented on CT images). We have provided systematic approaches for reviewing both conventional radiographs and CT scans to effectively assess the acetabulum. The clinical implications of the different fracture patterns have also been reviewed because it is critically important to include pertinent information for our clinical colleagues to provide the most efficient and timely clinical care.

  7. Fractured Craters on Ganymede

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Two highly fractured craters are visible in this high resolution image of Jupiter's moon, Ganymede. NASA's Galileo spacecraft imaged this region as it passed Ganymede during its second orbit through the Jovian system. North is to the top of the picture and the sun illuminates the surface from the southeast. The two craters in the center of the image lie in the ancient dark terrain of Marius Regio, at 40 degrees latitude and 201 degrees longitude, at the border of a region of bright grooved terrain known as Byblus Sulcus (the eastern portion of which is visible on the left of this image). Pervasive fracturing has occurred in this area that has completely disrupted these craters and destroyed their southern and western walls. Such intense fracturing has occurred over much of Ganymede's surface and has commonly destroyed older features. The image covers an area approximately 26 kilometers (16 miles) by 18 kilometers (11 miles) across at a resolution of 86 meters (287 feet) per picture element. The image was taken on September 6, 1996 by the solid state imaging (CCD) system on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://galileo.jpl.nasa.gov.

  8. Update on orbital reconstruction.

    PubMed

    Chen, Chien-Tzung; Chen, Yu-Ray

    2010-08-01

    Orbital trauma is common and frequently complicated by ocular injuries. The recent literature on orbital fracture is analyzed with emphasis on epidemiological data assessment, surgical timing, method of approach and reconstruction materials. Computed tomographic (CT) scan has become a routine evaluation tool for orbital trauma, and mobile CT can be applied intraoperatively if necessary. Concomitant serious ocular injury should be carefully evaluated preoperatively. Patients presenting with nonresolving oculocardiac reflex, 'white-eyed' blowout fracture, or diplopia with a positive forced duction test and CT evidence of orbital tissue entrapment require early surgical repair. Otherwise, enophthalmos can be corrected by late surgery with a similar outcome to early surgery. The use of an endoscope-assisted approach for orbital reconstruction continues to grow, offering an alternative method. Advances in alloplastic materials have improved surgical outcome and shortened operating time. In this review of modern orbital reconstruction, several controversial issues such as surgical indication, surgical timing, method of approach and choice of reconstruction material are discussed. Preoperative fine-cut CT image and thorough ophthalmologic examination are key elements to determine surgical indications. The choice of surgical approach and reconstruction materials much depends on the surgeon's experience and the reconstruction area. Prefabricated alloplastic implants together with image software and stereolithographic models are significant advances that help to more accurately reconstruct the traumatized orbit. The recent evolution of orbit reconstruction improves functional and aesthetic results and minimizes surgical complications.

  9. Petrophysical, Geochemical, and Hydrological Evidence for Extensive Fracture-Mediated Fluid and Heat Transport in the Alpine Fault's Hanging-Wall Damage Zone

    NASA Astrophysics Data System (ADS)

    Townend, John; Sutherland, Rupert; Toy, Virginia G.; Doan, Mai-Linh; Célérier, Bernard; Massiot, Cécile; Coussens, Jamie; Jeppson, Tamara; Janku-Capova, Lucie; Remaud, Léa.; Upton, Phaedra; Schmitt, Douglas R.; Pezard, Philippe; Williams, Jack; Allen, Michael John; Baratin, Laura-May; Barth, Nicolas; Becroft, Leeza; Boese, Carolin M.; Boulton, Carolyn; Broderick, Neil; Carpenter, Brett; Chamberlain, Calum J.; Cooper, Alan; Coutts, Ashley; Cox, Simon C.; Craw, Lisa; Eccles, Jennifer D.; Faulkner, Dan; Grieve, Jason; Grochowski, Julia; Gulley, Anton; Hartog, Arthur; Henry, Gilles; Howarth, Jamie; Jacobs, Katrina; Kato, Naoki; Keys, Steven; Kirilova, Martina; Kometani, Yusuke; Langridge, Rob; Lin, Weiren; Little, Tim; Lukacs, Adrienn; Mallyon, Deirdre; Mariani, Elisabetta; Mathewson, Loren; Melosh, Ben; Menzies, Catriona; Moore, Jo; Morales, Luis; Mori, Hiroshi; Niemeijer, André; Nishikawa, Osamu; Nitsch, Olivier; Paris, Jehanne; Prior, David J.; Sauer, Katrina; Savage, Martha K.; Schleicher, Anja; Shigematsu, Norio; Taylor-Offord, Sam; Teagle, Damon; Tobin, Harold; Valdez, Robert; Weaver, Konrad; Wiersberg, Thomas; Zimmer, Martin

    2017-12-01

    Fault rock assemblages reflect interaction between deformation, stress, temperature, fluid, and chemical regimes on distinct spatial and temporal scales at various positions in the crust. Here we interpret measurements made in the hanging-wall of the Alpine Fault during the second stage of the Deep Fault Drilling Project (DFDP-2). We present observational evidence for extensive fracturing and high hanging-wall hydraulic conductivity (˜10-9 to 10-7 m/s, corresponding to permeability of ˜10-16 to 10-14 m2) extending several hundred meters from the fault's principal slip zone. Mud losses, gas chemistry anomalies, and petrophysical data indicate that a subset of fractures intersected by the borehole are capable of transmitting fluid volumes of several cubic meters on time scales of hours. DFDP-2 observations and other data suggest that this hydrogeologically active portion of the fault zone in the hanging-wall is several kilometers wide in the uppermost crust. This finding is consistent with numerical models of earthquake rupture and off-fault damage. We conclude that the mechanically and hydrogeologically active part of the Alpine Fault is a more dynamic and extensive feature than commonly described in models based on exhumed faults. We propose that the hydrogeologically active damage zone of the Alpine Fault and other large active faults in areas of high topographic relief can be subdivided into an inner zone in which damage is controlled principally by earthquake rupture processes and an outer zone in which damage reflects coseismic shaking, strain accumulation and release on interseismic timescales, and inherited fracturing related to exhumation.

  10. Controversies in Treatment of Acetabular Fracture

    PubMed Central

    Grubor, Predrag; Krupic, Ferid; Biscevic, Mirza; Grubor, Milan

    2015-01-01

    Introduction: Acetabular fractures treatment represents a great controversy, challenge and dilemma for an orthopedic surgeon. Aim: The aim of the paper was to present the results of treatment of 96 acetabular fractures in the Clinic of Traumatology Banja Luka, in the period from 2003 to 2013, as well as to raise awareness regarding the controversy in the methods of choice in treating acetabulum fractures. Material and methods: The series consists of 96 patients, 82 males and 14 females, average age 40.5 years. Traffic trauma was the cause of fractures in 79 patients (85%), and in 17 patients (15%) fractures occurred due to falls from height. Polytrauma was present in 31 patients (32%). According to the classification of Judet and Letournel, representation of acetabular fractures was as follows: posterior wall in 32 patients, posterior column in 28, anterior wall in 4, anterior column in 2, transverse fractures in 8, posterior wall and posterior column in 10, anterior and posterior wall in 6, both- column in 4 and transversal fracture and posterior wall in 2 patients. 14 patients were treated with traction, that is, 6 patients with femoral traction and 8 patients with both lateral and femoral traction. 82 patients (86.4%) were surgically treated. Kocher-Langenbeck approach was applied in the treatment of 78 patients. In two patients from the Kocher-Langenbeck’s approach, the Ollier’s approach had to be applied as well. Two acetabular were primarily treated with Ollier’s approach. Extended Smith- Peterson’s approach was applied 4 times, and Emile Letournel’s (ilioinguinal) approach 14 times. Results: Functional outcome (after follow-up of 18 months), according to the Harris hip score of surgical treatment in 82 patients, was as follows: good 46 (56%), satisfactory 32 (39%) and poor 4 (5%). Results of acetabulum fractures treated with traction were: good 8 (57%), satisfactory 4 (28%) and poor 2 (15%). According to the Brook’s classification of heterotopic

  11. Improvement of the fracture toughness of hydroxyapatite (HAp) by incorporation of carboxyl functionalized single walled carbon nanotubes (CfSWCNTs) and nylon

    DOE PAGES

    Khanal, Suraj P.; Mahfuz, Hassan; Rondinone, Adam Justin; ...

    2015-11-12

    The potential of improving the fracture toughness of synthetic hydroxyapatite (HAp) by incorporating carboxyl functionalized single walled carbon nanotubes (CfSWCNTs) and polymerized ε-caprolactam (nylon) was researched. A series of HAp samples with CfSWCNTs concentrations varying from 0 to 1.5 wt.%, without, and with nylon addition was prepared. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Transmission Electron Microscopy (TEM) were used to characterize the samples. The three point bending test was applied to measure the fracture toughness of the composites. A reproducible value of 3.6 ± 0.3 MPa.√m was found for samples containing 1 wt.% CfSWCNTs and nylon. This valuemore » is in the range of the cortical bone fracture toughness. Lastly, the increase of the CfSWCNTs content results to decrease of the fracture toughness, and formation of secondary phases.« less

  12. Fractures on Europa - Possible response of an ice crust to tidal deformation

    NASA Technical Reports Server (NTRS)

    Helfenstein, P.; Parmentier, E. M.

    1980-01-01

    The surface of Europa contains a planetwide system of low albedo lineaments which have been interpreted as fractures in an icy crust. The pattern of fractures on the surface consists of radial and concentric fractures having the general appearance of tension cracks within a region near the antipode of the sub-Jupiter point. Outside this region, linear fractures intersect at angles near 60 deg, suggesting that they are conjugate shear fractures. The orientation of this pattern on the surface suggests that a principal axis of the deformation that produced the fractures was approximately radial to Jupiter. Fracturing may thus be consistent with an origin due to cyclical tidal deformation resulting from orbital eccentricity. Orbital eccentricity related to a relatively recent establishment of orbital resonance among the Galilean satellites may explain the presence of fractures in a relatively young, lightly cratered planetary surface.

  13. Fracture detection logging tool

    DOEpatents

    Benzing, William M.

    1992-06-09

    A method and apparatus by which fractured rock formations are identified and their orientation may be determined includes two orthogonal motion sensors which are used in conjunction with a downhole orbital vibrator. The downhole vibrator includes a device for orienting the sensors. The output of the sensors is displayed as a lissajou figure. The shape of the figure changes when a subsurface fracture is encountered in the borehole. The apparatus and method identifies fractures rock formations and enables the azimuthal orientation of the fractures to be determined.

  14. Structure of the cell envelope of corynebacteria: importance of the non-covalently bound lipids in the formation of the cell wall permeability barrier and fracture plane.

    PubMed

    Puech, V; Chami, M; Lemassu, A; Lanéelle, M A; Schiffler, B; Gounon, P; Bayan, N; Benz, R; Daffé, M

    2001-05-01

    With the recent success of the heterologous expression of mycobacterial antigens in corynebacteria, in addition to the importance of these bacteria in biotechnology and medicine, a better understanding of the structure of their cell envelopes was needed. A combination of molecular compositional analysis, ultrastructural appearance and freeze-etch electron microscopy study was used to arrive at a chemical model, unique to corynebacteria but consistent with their phylogenetic relatedness to mycobacteria and other members of the distinctive suprageneric actinomycete taxon. Transmission electron microscopy and chemical analyses showed that the cell envelopes of the representative strains of corynebacteria examined consisted of (i) an outer layer composed of polysaccharides (primarily a high-molecular-mass glucan and arabinomannans), proteins, which include the mycoloyltransferase PS1, and lipids; (ii) a cell wall glycan core of peptidoglycan-arabinogalactan which may contain other sugar residues and was usually esterified by corynomycolic acids; and (iii) a typical plasma membrane bilayer. Freeze-etch electron microscopy showed that most corynomycolate-containing strains exhibited a main fracture plane in their cell wall and contained low-molecular-mass porins, while the fracture occurred within the plasma membrane of strains devoid of both corynomycolate and pore-forming proteins. Importantly, in most strains, the amount of cell wall-linked corynomycolates was not sufficient to cover the bacterial surface; interestingly, the occurrence of a cell wall fracture plane correlated with the amount of non-covalently bound lipids of the strains. Furthermore, these lipids were shown to spontaneously form liposomes, indicating that they may participate in a bilayer structure. Altogether, the data suggested that the cell wall permeability barrier in corynebacteria involved both covalently linked corynomycolates and non-covalently bound lipids of their cell envelopes.

  15. Fracture and Failure in Micro- and Nano-Scale

    NASA Astrophysics Data System (ADS)

    Charitidis, Costas A.

    Indentation and scratch in micro- and nano-scale are the most commonly used techniques for quantifying thin film and systems properties. Among them are different failure modes such as deformation, friction, fracture toughness, fatigue. Failure modes can be activated either by a cycle of indentation or by scratching of the samples to provide an estimation of the fracture toughness and interfacial fracture energies. In the present study, we report on the failure and fracture modes in two cases of engineering materials; that is transparent SiOx thin films onto poly(ethylene terephthalate) (PET) membranes and glass-ceramic materials. The SiOx/PET system meets the demands regarding scratch-resistance, wettability, biocompatibility, gas transmission, or friction, while maintaining the bulk characteristics of PET (such as easy processing, good mechanical properties, reasonably low permeability to oxygen and carbon dioxide gases (barrier properties), and good chemical coupling with antibacterial coatings). Glass-ceramic materials, since their first accidental production in the mid fifties by S.D. Stookey, have been used in a vast area of applications, from household cooktops and stoves, to missile nose cones and mirror mounts of orbital telescopes and from decorative wall coverings to medical applications. The fracture modes, namely transgranular and intergranular modes in glass-ceramic materials have paid less attention in literature comparing with ceramic materials. In the former case the crack paves its way irrespectively of the direction of the grain boundaries, i.e., the interfaces between the different phases. In the latter case the crack preferentially follows them, i.e., debonds the interfaces.

  16. Pictorial essay: Orbital tuberculosis

    PubMed Central

    Narula, Mahender K; Chaudhary, Vikas; Baruah, Dhiraj; Kathuria, Manoj; Anand, Rama

    2010-01-01

    Tuberculosis of the orbit is rare, even in places where tuberculosis is endemic. The disease may involve soft tissue, the lacrimal gland, or the periosteum or bones of the orbital wall. Intracranial extension, in the form of extradural abscess, and infratemporal fossa extension has been described. This pictorial essay illustrates the imaging findings of nine histopathologically confirmed cases of orbital tuberculosis. All these patients responded to antituberculous treatment. PMID:20351984

  17. Deep lateral wall orbital decompression following strabismus surgery in patients with Type II ophthalmic Graves' disease.

    PubMed

    Ellis, Michael P; Broxterman, Emily C; Hromas, Alan R; Whittaker, Thomas J; Sokol, Jason A

    2018-01-10

    Surgical management of ophthalmic Graves' disease traditionally involves, in order, orbital decompression, followed by strabismus surgery and eyelid surgery. Nunery et al. previously described two distinct sub-types of patients with ophthalmic Graves' disease; Type I patients exhibit no restrictive myopathy (no diplopia) as opposed to Type II patients who do exhibit restrictive myopathy (diplopia) and are far more likely to develop new-onset worsening diplopia following medial wall and floor decompression. Strabismus surgery involving extra-ocular muscle recession has, in turn, been shown to potentially worsen proptosis. Our experience with Type II patients who have already undergone medial wall and floor decompression and strabismus surgery found, when additional decompression is necessary, deep lateral wall decompression (DLWD) appears to have a low rate of post-operative primary-gaze diplopia. A case series of four Type II ophthalmic Graves' disease patients, all of whom had already undergone decompression and strabismus surgery, and went on to develop worsening proptosis or optic nerve compression necessitating further decompression thereafter. In all cases, patients were treated with DLWD. Institutional Review Board approval was granted by the University of Kansas. None of the four patients treated with this approach developed recurrent primary-gaze diplopia or required strabismus surgery following DLWD. While we still prefer to perform medial wall and floor decompression as the initial treatment for ophthalmic Graves' disease, for proptosis following consecutive strabismus surgery, DLWD appears to be effective with a low rate of recurrent primary-gaze diplopia.

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

    Hammeschlag, S.B.; Hughes, S.; O'Reilly, G.V.

    Orbital blow-out fractures were experimentally created in eight human cadavers. Each orbit underwent conventional radiographic studies, complex motion tomography, and computed tomographic examinations. A comparison of the three modalities was made. Anatomical correlation was obtained by dissecting the orbits. The significance of medial-wall fractures and enophthalmos is discussed. Limitation of inferior rectus muscle mobility is thought to be a result of muscle kinking associated with orbital fat-pad prolapse at the fracture site, rather than muscle incarceration. Blow-out fractures should be evaluated by computed tomographic computer reformations in the oblique sagittal plane.

  19. Melt fracture revisited

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

    Greenberg, J. M.

    2003-07-16

    In a previous paper the author and Demay advanced a model to explain the melt fracture instability observed when molten linear polymer melts are extruded in a capillary rheometer operating under the controlled condition that the inlet flow rate was held constant. The model postulated that the melts were a slightly compressible viscous fluid and allowed for slipping of the melt at the wall. The novel feature of that model was the use of an empirical switch law which governed the amount of wall slip. The model successfully accounted for the oscillatory behavior of the exit flow rate, typically referredmore » to as the melt fracture instability, but did not simultaneously yield the fine scale spatial oscillations in the melt typically referred to as shark skin. In this note a new model is advanced which simultaneously explains the melt fracture instability and shark skin phenomena. The model postulates that the polymer is a slightly compressible linearly viscous fluid but assumes no slip boundary conditions at the capillary wall. In simple shear the shear stress {tau}and strain rate d are assumed to be related by d = F{tau} where F ranges between F{sub 2} and F{sub 1} > F{sub 2}. A strain rate dependent yield function is introduced and this function governs whether F evolves towards F{sub 2} or F{sub 1}. This model accounts for the empirical observation that at high shears polymers align and slide more easily than at low shears and explains both the melt fracture and shark skin phenomena.« less

  20. The Interior and Orbital Evolution of Charon as Preserved in Its Geologic Record

    NASA Technical Reports Server (NTRS)

    Rhoden, Alyssa Rose; Henning, Wade; Hurford, Terry A.; Hamilton, Douglas P.

    2014-01-01

    Pluto and its largest satellite, Charon, currently orbit in a mutually synchronous state; both bodies continuously show the same face to one another. This orbital configuration is a natural end-state for bodies that have undergone tidal dissipation. In order to achieve this state, both bodies would have experienced tidal heating and stress, with the extent of tidal activity controlled by the orbital evolution of Pluto and Charon and by the interior structure and rheology of each body. As the secondary, Charon would have experienced a larger tidal response than Pluto, which may have manifested as observable tectonism. Unfortunately, there are few constraints on the interiors of Pluto and Charon. In addition, the pathway by which Charon came to occupy its present orbital state is uncertain. If Charon's orbit experienced a high-eccentricity phase, as suggested by some orbital evolution models, tidal effects would have likely been more significant. Therefore, we determine the conditions under which Charon could have experienced tidally-driven geologic activity and the extent to which upcoming New Horizons spacecraft observations could be used to constrain Charon's internal structure and orbital evolution. Using plausible interior structure models that include an ocean layer, we find that tidally-driven tensile fractures would likely have formed on Charon if its eccentricity were on the order of 0.01, especially if Charon were orbiting closer to Pluto than at present. Such fractures could display a variety of azimuths near the equator and near the poles, with the range of azimuths in a given region dependent on longitude; east-west-trending fractures should dominate at mid-latitudes. The fracture patterns we predict indicate that Charon's surface geology could provide constraints on the thickness and viscosity of Charon's ice shell at the time of fracture formation.

  1. [Treatment of enophthalmos after severe malar-maxillary complex fracture with titanium mesh and high density polyethylene (Medpor)].

    PubMed

    Zhao, Yan-feng; Lu, Ping; Zhou, Xiao-nan; Qu, Chang-feng

    2010-03-01

    To study the surgical management of enophthalmos after severe malar maxillary complex fracture. The X-ray and CT examination were performed before operation to diagnose the orbital fracture and intraorbital tissue displacement. The fractured orbital rim was repositioned intraoperatively, followed by implantation of shaped titanium mesh to rebuild the orbital floor. The Medpor was inserted above the titanium mesh to correct the enophthalmos. From Sept. 2007 to Jan. 2009, 6 cases of enophthalmos after severe malar-maxillary complex fracture were treated. The enophthalmos was corrected or improved obviously in all the patients. The enophthalmos after severe malar-maxillary complex fracture can be corrected or obviously improved. Shaped titanium mesh can be used to rebuild the orbital floor with the Medpor to reconstruct the intraorbital tissue volume.

  2. [Orbital compartment syndrome. The most frequent cause of blindness following facial trauma].

    PubMed

    Klenk, Gusztáv; Katona, József; Kenderfi, Gábor; Lestyán, János; Gombos, Katalin; Hirschberg, Andor

    2017-09-01

    Although orbital compartment syndrome is a rare condition, it is still the most common cause of blindness following simple or complicated facial fractures. Its pathomechanism is similar to the compartment syndrome in the limb. Little extra fluid (blood, oedema, brain, foreign body) in a non-space yielding space results with increasingly higher pressures within a short period of time. Unless urgent surgical intervention is performed the blocked circulation of the central retinal artery will result irreversible ophthalmic nerve damage and blindness. Aim, material and method: A retrospective analysis of ten years, 2007-2017, in our hospital among those patients referred to us with facial-head trauma combined with blindness. 571 patients had fractures involving the orbit. 23 patients become blind from different reasons. The most common cause was orbital compartment syndrome in 17 patients; all had retrobulbar haematomas as well. 6 patients with retrobulbar haematoma did not develop compartment syndrome. Compartment syndrome was found among patient with extensive and minimal fractures such as with large and minimal haematomas. Early lateral canthotomy and decompression saved 7 patients from blindness. We can not predict and do not know why some patients develop orbital compartment syndrome. Compartment syndrome seems independent from fracture mechanism, comminution, dislocation, amount of orbital bleeding. All patients are in potential risk with midface fractures. We have a high suspicion that orbital compartment syndrome has been somehow missed out in the recommended textbooks of our medical universities and in the postgraduate trainings. Thus compartment syndrome is not recognized. Teaching, training and early surgical decompression is the only solution to save the blind eye. Orv Hetil. 2017; 158(36): 1410-1420.

  3. [Orbital decompression in Grave's disease: comparison of techniques].

    PubMed

    Sellari-Franceschini, S; Berrettini, S; Forli, F; Bartalena, L; Marcocci, C; Tanda, M L; Nardi, M; Lepri, A; Pinchera, A

    1999-12-01

    Grave's ophthalmopathy is an inflammatory, autoimmune disorder often associated with Grave's disease. The inflammatory infiltration involves the retrobulbar fatty tissue and the extrinsic eye muscles, causing proptosis, extraocular muscle dysfunction and often diplopia. Orbital decompression is an effective treatment in such cases, particularly when resistant to drugs and external radiation therapy. This work compares the results of orbital decompression performed by removing: a) the medial and lateral walls (Mourits technique) in 10 patients (19 orbits) and b) the medial and lower walls (Walsh-Ogura technique) in 17 patients (31 orbits). The results show that removing the floor of the orbit enables better reduction of proptosis but more easily leads to post-operative diplopia. Thus it proves necessary to combine the two techniques, modifying the surgical approach on a case-by-case basis.

  4. Morphology of the posteromedial fragment in pertrochanteric fractures: A three-dimensional computed tomography analysis.

    PubMed

    Sharma, Gaurav; Gn, Kiran Kumar; Khatri, Kavin; Singh, Ravijot; Gamanagatti, Shivanand; Sharma, Vijay

    2017-02-01

    In this study we describe the morphology of the posteromedial fragment in pertrochanteric fractures using 3D CT scans and answer two questions 1) Do differences exist between the 3D CT appearances of posteromedial fragments and the depictions made in the AO classification 2) Does the posteromedial fragment affect stability in pertrochanteric fractures, in terms of fracture collapse? Preoperative CT scans of eight 31-A1 and fifty 31-A2 fractures were analysed. The presence of PM fragment, its fragmentation, greater trochanter (GT) involvement, lesser trochanter (LT) fragment size (in terms of its posterior and medial extent as well as LT length), LT fragment displacement (in terms of medial displacement and rotation) were determined. All fractures were treated with a DHS. Fracture collapse was determined on postoperative radiographs. The relationship between fracture collapse and patient factors including age, gender, fracture type (A1 versus A2), characteristics of the posteromedial fragment, and the presence of a lateral wall fracture were determined. Three out of eight 31-A1 fractures demonstrated a separate GT fragment (three part fracture). Out of the 50 31-A2 fractures, 12 had a single PM fragment, which included the LT and GT in continuity. The more common four part fractures seem to form by further fragmentation of this basic form. In A2 fractures, the GT was almost always broken and the broken fragment comprised a mean 56% of normal GT. The LT fragment involved an average of 74% of the posterior wall, and an average of 36% of the medial wall of the proximal femur. Larger LT fragments were less displaced as compared to smaller fragments. Univariate regression analyses revealed that fracture collapse was significantly correlated with fracture type (A1 versus A2, p 0.036), GT size (p 0.002) and the presence of a lateral wall fracture (p<0.001). This study revealed some important differences between the 3D CT appearances and AO classification of pertrochanteric

  5. Stereoscopic three-dimensional images of an anatomical dissection of the eyeball and orbit for educational purposes.

    PubMed

    Matsuo, Toshihiko; Takeda, Yoshimasa; Ohtsuka, Aiji

    2013-01-01

    The purpose of this study was to develop a series of stereoscopic anatomical images of the eye and orbit for use in the curricula of medical schools and residency programs in ophthalmology and other specialties. Layer-by-layer dissection of the eyelid, eyeball, and orbit of a cadaver was performed by an ophthalmologist. A stereoscopic camera system was used to capture a series of anatomical views that were scanned in a panoramic three-dimensional manner around the center of the lid fissure. The images could be rotated 360 degrees in the frontal plane and the angle of views could be tilted up to 90 degrees along the anteroposterior axis perpendicular to the frontal plane around the 360 degrees. The skin, orbicularis oculi muscle, and upper and lower tarsus were sequentially observed. The upper and lower eyelids were removed to expose the bulbar conjunctiva and to insert three 25-gauge trocars for vitrectomy at the location of the pars plana. The cornea was cut at the limbus, and the lens with mature cataract was dislocated. The sclera was cut to observe the trocars from inside the eyeball. The sclera was further cut to visualize the superior oblique muscle with the trochlea and the inferior oblique muscle. The eyeball was dissected completely to observe the optic nerve and the ophthalmic artery. The thin bones of the medial and inferior orbital wall were cracked with a forceps to expose the ethmoid and maxillary sinus, respectively. In conclusion, the serial dissection images visualized aspects of the local anatomy specific to various procedures, including the levator muscle and tarsus for blepharoptosis surgery, 25-gauge trocars as viewed from inside the eye globe for vitrectomy, the oblique muscles for strabismus surgery, and the thin medial and inferior orbital bony walls for orbital bone fractures.

  6. Rib fixation for severe chest deformity due to multiple rib fractures.

    PubMed

    Igai, Hitoshi; Kamiyoshihara, Mitsuhiro; Nagashima, Toshiteru; Ohtaki, Yoichi

    2012-01-01

    The operative indications for rib fracture repair have been a matter of debate. However, several reports have suggested that flail chest, pain on respiration, and chest deformity/defect are potential conditions for rib fracture repair. We describe our experience of rib fixation in a patient with severe chest deformity due to multiple rib fractures. A 70-year-old woman was admitted with right-sided multiple rib fractures (2nd to 7th) and marked chest wall deformity without flailing caused by an automobile accident. Collapse of the chest wall was observed along the middle anterior axillary line. At 11 days after the injury, surgery was performed to repair the chest deformity, as it was considered to pose a risk of restrictive impairment of pulmonary function or chronic intercostal pain in the future. Operative findings revealed marked displacement of the superior 4 ribs, from the 2nd to the 5th, and collapse of the osseous chest wall towards the thoracic cavity. After exposure of the fracture regions, ribs fixations were performed using rib staplers. The total operation time was 90 minutes, and the collapsed portion of the chest wall along the middle anterior axillary line was reconstructed successfully.

  7. The Influence of Socioeconomic Factors on the Epidemiology of Maxillofacial Fractures in Southern Italy.

    PubMed

    Sbordone, Carolina; Barca, Ida; Petrocelli, Marzia; Dell'Aversana Orabona, Giovanni; Vaira, Luigi Angelo; Colangeli, Walter; Cristofaro, Maria Giulia; Giudice, Mario; Giudice, Amerigo; Cassandro, Francesco Maria; Attanasi, Federica; Iaconetta, Giorgio; Califano, Luigi

    2018-05-15

    Maxillofacial fractures represent a serious public health problem. Their epidemiology is extremely variable and its analysis is crucial to establish effective treatment and prevention of these injuries. The aim of this multicentric retrospective study was to analyze causes, demographics, incidence, characteristics of 987 patients diagnosed with maxillofacial trauma between 2011 and 2015 at Complex Operative Unit of Maxillofacial Surgery of Federico II University of Naples and Magna Graecia University of Catanzaro, Italy; 657 male and 310 female patients were admitted in the study. The most frequently observed fracture involved the mandible (399 patients, 35.4%), followed by zygomatic complex (337 patients, 29.9%), orbital walls (160 patients, 14.2%), and nasal bones (129 patients, 11.4%). The most frequent cause of fracture was assaults (30.4%), followed by road traffic injuries (27.2%), falls (23.2%), sport accidents (15.4%), and others causes (2.6%). Significant variations of etiology have been detected between the 2 hospitals in relationship with different migration flow trends and cultural and socioeconomic features. Epidemiological analysis of maxillofacial fractures is crucial to identify the trauma burden and to help in developing a more efficient system to plan resource allocation and to deliver care and preventive measures establishing clinical and research priorities for effective treatment and prevention of these injuries.

  8. Posttraumatic Intracranial Tuberculous Subdural Empyema in a Patient with Skull Fracture

    PubMed Central

    Kim, Jiha; Kim, Choonghyo; Ryu, Young-Joon

    2016-01-01

    Intracranial tuberculous subdural empyema (ITSE) is extremely rare. To our knowledge, only four cases of microbiologically confirmed ITSE have been reported in the English literature to date. Most cases have arisen in patients with pulmonary tuberculosis regardless of trauma. A 46-year-old man presented to the emergency department after a fall. On arrival, he complained of pain in his head, face, chest and left arm. He was alert and oriented. An initial neurological examination was normal. Radiologic evaluation revealed multiple fractures of his skull, ribs, left scapula and radius. Though he had suffered extensive skull fractures of his cranium, maxilla, zygoma and orbital wall, the sustained cerebral contusion and hemorrhage were mild. Eighteen days later, he suddenly experienced a general tonic-clonic seizure. Radiologic evaluation revealed a subdural empyema in the left occipital area that was not present on admission. We performed a craniotomy, and the empyema was completely removed. Microbiological examination identified Mycobacterium tuberculosis (M. tuberculosis). After eighteen months of anti-tuberculous treatment, the empyema disappeared completely. This case demonstrates that tuberculosis can induce empyema in patients with skull fractures. Thus, we recommend that M. tuberculosis should be considered as the probable pathogen in cases with posttraumatic empyema. PMID:27226867

  9. Complications of orbital floor repair with silastic sheet: the skin fistula.

    PubMed

    Aboh, Ikenna Valentine; Chisci, Glauco; Gennaro, Paolo; Giovannetti, Filippo; Bartoli, Davina; Priore, Paolo; Anelli, Andrea; Iannetti, Giorgio

    2013-07-01

    Treatment of orbital floor fracture is a subject of great interest in maxillofacial surgery. Many materials have been described for its reconstruction.In this article, the authors report a case of a patient who, 7 years from a previous orbital floor fracture and treatment with silastic sheet, presented herself to their clinic for the failure of the material used for its reconstruction and a skin fistula.Orbital floor repair with silastic sheet is an old method that no one uses anymore, but we still observe cases of late complications with this material. So a fine knowledge of silastic sheet complications is needed for young surgeons.The authors report the case and perform a literature review about the use of more modern biomaterials for orbital floor reconstruction.

  10. Use of Orbital Conformer to Improve Speech in Patients with Confluent Maxillectomy and Orbital Defects

    PubMed Central

    Colebeck, Amanda C.; Kase, Michael T.; Nichols, Cindy B.; Golden, Marjorie; Huryn, Joseph M.

    2016-01-01

    The basic objective in prosthetic restoration of confluent maxillary and orbital defects is to achieve a comfortable, cosmetically acceptable prosthesis that restores speech, deglutition, and mastication. It is a challenging task complicated by the size and shape of the defects. The maxillary obturator prosthesis often satisfies the objective of adequate deglutition; however, orbital defects that are not obturated in the medial septal or posterior walls allow air to escape, negatively impacting phonation. This article describes a technique to achieve favorable prosthetic rehabilitation in a patient with a maxillectomy and ipsilateral orbital exenteration. The prosthetic components include maxillary obturator, orbital conformer, and orbital prosthesis connected using rigid magnetic attachments. PMID:25953143

  11. General view of he forward wall of the mid deck ...

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

    General view of he forward wall of the mid deck of the Orbiter Discovery. In this view a majority of wall panels have been removed to reveal the avionics bays in the interstitial space between the mid deck forward wall and the forward bulkhead of the pressurized crew compartment. This photograph was taken at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  12. Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

    PubMed Central

    2011-01-01

    Background Chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT), appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer Materials and methods A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated. Results Rib fracture was identified on follow-up CT in 41 patients (23.2%). Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months). Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%), of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms. Conclusion Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present. PMID:21995807

  13. Prolonged pain and disability are common after rib fractures.

    PubMed

    Fabricant, Loic; Ham, Bruce; Mullins, Richard; Mayberry, John

    2013-05-01

    The contribution of rib fractures to prolonged pain and disability may be underappreciated and undertreated. Clinicians are traditionally taught that the pain and disability of rib fractures resolves in 6 to 8 weeks. This study was a prospective observation of 203 patients with rib fractures at a level 1 trauma center. Chest wall pain was evaluated by the McGill Pain Questionnaire (MPQ) pain rating index (PRI) and present pain intensity (PPI). Prolonged pain was defined as a PRI of 8 or more at 2 months after injury. Prolonged disability was defined as a decrease in 1 or more levels of work or functional status at 2 months after injury. Predictors of prolonged pain and disability were determined by multivariate analysis. One hundred forty-five male patients and 58 female patients with a mean injury severity score (ISS) of 20 (range, 1 to 59) had a mean of 5.4 rib fractures (range, 1 to 29). Forty-four (22%) patients had bilateral fractures, 15 (7%) had flail chest, and 92 (45%) had associated injury. One hundred eighty-seven patients were followed 2 months or more. One hundred ten (59%) patients had prolonged chest wall pain and 142 (76%) had prolonged disability. Among 111 patients with isolated rib fractures, 67 (64%) had prolonged chest wall pain and 69 (66%) had prolonged disability. MPQ PPI was predictive of prolonged pain (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.4 to 2.5), and prolonged disability (OR, 2.2; 95% CI, 1.5 to 3.4). The presence of significant associated injuries was predictive of prolonged disability (OR, 5.9; 95% CI, 1.4 to 29). Prolonged chest wall pain is common, and the contribution of rib fractures to disability is greater than traditionally expected. Further investigation into more effective therapies that prevent prolonged pain and disability after rib fractures is needed. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. Percolation and permeability of heterogeneous fracture networks

    NASA Astrophysics Data System (ADS)

    Adler, Pierre; Mourzenko, Valeri; Thovert, Jean-François

    2013-04-01

    Natural fracture fields are almost necessarily heterogeneous with a fracture density varying with space. Two classes of variations are quite frequent. In the first one, the fracture density is decreasing from a given surface; the fracture density is usually (but not always see [1]) an exponential function of depth as it has been shown by many measurements. Another important example of such an exponential decrease consists of the Excavated Damaged Zone (EDZ) which is created by the excavation process of a gallery [2,3]. In the second one, the fracture density undergoes some local random variations around an average value. This presentation is mostly focused on the first class and numerical samples are generated with an exponentially decreasing density from a given plane surface. Their percolation status and hydraulic transmissivity can be calculated by the numerical codes which are detailed in [4]. Percolation is determined by a pseudo diffusion algorithm. Flow determination necessitates the meshing of the fracture networks and the discretisation of the Darcy equation by a finite volume technique; the resulting linear system is solved by a conjugate gradient algorithm. Only the flow properties of the EDZ along the directions which are parallel to the wall are of interest when a pressure gradient parallel to the wall is applied. The transmissivity T which relates the total flow rate per unit width Q along the wall through the whole fractured medium to the pressure gradient grad p, is defined by Q = - T grad p/mu where mu is the fluid viscosity. The percolation status and hydraulic transmissivity are systematically determined for a wide range of decay lengths and anisotropy parameters. They can be modeled by comparison with anisotropic fracture networks with a constant density. A heuristic power-law model is proposed which accurately describes the results for the percolation threshold over the whole investigated range of heterogeneity and anisotropy. Then, the data

  15. Primary surgical excision for pediatric orbital capillary hemangioma.

    PubMed

    Krema, Hatem

    2015-05-01

    We report the technique and outcome of surgical excision of subcutaneous orbital capillary hemangioma causing eye globe displacement in two children. Primary surgical excision was performed with blunt dissection along the tumor walls using a cotton-tipped applicator as the dissecting tool with simultaneous outward gentle traction on the tumor wall. Despite the deep and extensive orbital involvement, complete excision of the hemangiomas was achievable with this technique, which permitted excellent visualization of the surgical planes throughout the procedures. Deep and extensive pediatric orbital capillary hemangioma can be surgically excised with the suggested technique, which obviates the need for intralesional or systemic medical therapy, yielding optimal cosmetic and functional outcomes, shortly after surgery.

  16. Brittle fracture damage around the Alpine Fault, New Zealand

    NASA Astrophysics Data System (ADS)

    Williams, J. N.; Toy, V.; Smith, S. A. F.; Boulton, C. J.; Massiot, C.; Mcnamara, D. D.

    2017-12-01

    We use field and drill-core samples to characterize macro- to micro-scale brittle fracture networks within the hanging-wall of New Zealand's Alpine Fault, an active plate-boundary fault that is approaching the end of its seismic cycle. Fracture density in the hanging-wall is roughly constant for distances of up to 500 m from the principal slip zone gouges (PSZs). Fractures >160 m from the PSZs are typically open and parallel to the regional mylonitic foliation or host rock schistosity, and likely formed as unloading joints during rapid exhumation of the hanging-wall at shallow depths. Fractures within c. 160 m of the PSZs are broadly oriented shear-fractures filled with gouge or cataclasite, and are interpreted to constitute the hanging-wall damage zone of the Alpine Fault. This is comparable to the 60-200 m wide "geophysical damage zone" estimated from low seismic wave velocities surrounding the Alpine Fault. Veins are pervasive within the c. 20 m-thick hanging-wall cataclasites and are most commonly filled by calcite, chlorite, muscovite and K-feldspar. Notably, there is a set of intragranular clast-hosted veins, as well as a younger set of veins that cross-cut both clasts and cataclasite matrix. The intragranular veins formed prior to cataclasis or during synchronous cataclasis and calcite-silicate mineralisation. Broad estimates for the depth of vein formation indicate that the cataclasites formed a c. 20 m wide actively deforming zone at depths of c. 4-8 km. Conversely, the cross-cutting veins are interpreted to represent off-fault damage within relatively indurated cataclasites following slip localization onto the <10 cm wide smectite-bearing PSZ gouges at depths of <4 km. Our observations therefore highlight a strong depth-dependence of the width of the actively deforming zone within the brittle seismogenic crust around the Alpine Fault.

  17. Fracture-network 3D characterization in a deformed chalk reservoir analogue -- the Laegerdorf case

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

    Koestler, A.G.; Reksten, K.

    1995-09-01

    Quantitative descriptions of 3D fracture networks in terms of fracture characteristics and connectivity are necessary for reservoir evaluation, management, and EOR programs of fractured reservoirs. The author`s research has focused on an analogue to North Sea fractured chalk reservoirs that is excellently exposed near Laegerdorf, northwest Germany. An underlying salt diapir uplifted and deformed Upper Cretaceous chalk; the cement industry now exploits it. The fracture network in the production wall of the quarry was characterized and mapped at different scales, and 12 profiles of the 230-m wide and 35-m high production wall were investigated as the wall receded 25 m.more » In addition, three wells were drilled into the chalk volume. The wells were cored and the wellbores were imaged with both the resistivity formation micro scanner (FMS) and the sonic circumferential borehole image logger (CBIL). The large amount of fracture data was analyzed with respect to parameters, such as fracture density distribution, orientation, and length distribution, and in terms of the representativity and predictability of data sets collected from restricted rock volumes.« less

  18. Particle Swarm Transport across the Fracture-Matrix Interface

    NASA Astrophysics Data System (ADS)

    Malenda, M. G.; Pyrak-Nolte, L. J.

    2016-12-01

    A fundamental understanding of particle transport is required for many diverse applications such as effective proppant injection, for deployment of subsurface imaging micro-particles, and for removal of particulate contaminants from subsurface water systems. One method of particulate transport is the use of particle swarms that act as coherent entities. Previous work found that particle swarms travel farther and faster in single fractures than individual particles when compared to dispersions and emulsions. In this study, gravity-driven experiments were performed to characterize swarm transport across the fracture-matrix interface. Synthetic porous media with a horizontal fracture were created from layers of square-packed 3D printed (PMMA) spherical grains (12 mm diameter). The minimum fracture aperture ranged from 0 - 10 mm. Swarms (5 and 25 µL) were composed of 3.2 micron diameter fluorescent polystryene beads (1-2% by mass). Swarms were released into a fractured porous medium that was submerged in water and was illuminated with a green (528 nm) LED array. Descending swarms were imaged with a CCD camera (2 fps). Whether an intact swarm was transported across a fracture depended on the volume of the swarm, the aperture of the fracture, and the alignment of pores on the two fracture walls. Large aperture fractures caused significant deceleration of a swarm because the swarm was free to expand laterally in the fracture. Swarms tended to remain intact when the pores on the two fracture walls were vertically aligned and traveled in the lower porous medium with speeds that were 30%-50% of their original speed in the upper matrix. When the pores on opposing walls were no longer aligned, swarms were observed to bifurcate around the grain into two smaller slower-moving swarms. Understanding the physics of particle swarms in fractured porous media has important implications for enhancing target particulate injection into the subsurface as well as for contaminant

  19. Sonography of occult rib and costal cartilage fractures: a case series.

    PubMed

    Mattox, Ross; Reckelhoff, Kenneth E; Welk, Aaron B; Kettner, Norman W

    2014-06-01

    The purpose of this case series is to describe the use of diagnostic ultrasound (US) in the detection of occult rib and costal cartilage fractures presenting as chest wall pain to a chiropractic clinic. Three patients presented with chest wall pain and tenderness. Two of the patients presented with acute chest wall injury and 1 carried a previous diagnosis of rib fracture after trivial trauma 2 months earlier. Diagnostic US was selected as a non-ionizing imaging tool for these patients after negative digital radiography studies. All fractures were considered isolated as there was no associated injury, such as pneumothorax. Both of the acute cases were followed up to complete healing (evidence of osseous union) using US. All patients eventually achieved pain-free status. In these cases, US was more sensitive than radiography for diagnosing these cases of acute rib and costal cartilage fractures. Early recognition of rib injury could avoid potential complications from local manipulative therapy.

  20. Fracture formation post impact on Enceladus?

    NASA Astrophysics Data System (ADS)

    Craft, Kathleen; Roberts, James

    2017-10-01

    Saturn’s small icy moon Enceladus was observed by the Cassini mission to have jets of ice and vapor emanating from its southern polar terrain (SPT), creating a plume. The fact that the activity is only observed in one region has not been well explained. Hypotheses include a regional sea beneath the SPT or a global ocean that is thicker beneath the SPT, which feeds a group of fractures observed there called the tiger stripes. As Enceladus orbits Saturn, stresses acting on the moon may open and close the fractures enabling interior volatiles to escape and form the plume. Here we investigate how these fractures could have formed and the activity begun. We propose that an impact could have either punctured through or caused substantial melt and fracturing in an ice shell connecting to a liquid layer below. Our goal is to determine whether a formation of fractures resembling the tiger stripes could emerge post-impact.Previous work by Roberts and Stickle (LPSC 2017, #1955) modeled an impact into an ice shell over an ocean and calculated penetration depth and melt temperatures and volumes through the shell thickness. Fracturing would occur during and after the impact, the crater would collapse, water would begin to refreeze and subsequent fluid exchange would occur. Working forward from a point after impact and as the ice shell begins refreezing, we performed finite element modeling to simulate the probable formation of fractures based on the resulting stress regime. Here we explore fracture formation for shells ranging from 1 km to 5 km thick (consistent with gravity and libration studies), to explore formation as the shell cools and thickens through time. We emplaced several fractures, penetrating either entirely or partially across the base to surface. Fracture interactions, tidal stress forcing with orbital true anomalies and ocean water pressurization are considered free parameters in the model. We present results for a number of parameter value combinations and

  1. Fracture control for the Oman India Pipeline

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

    Bruno, T.V.

    1996-12-31

    This paper describes the evaluation of the resistance to fracture initiation and propagation for the high-strength, heavy-wall pipe required for the Oman India Pipeline (OIP). It discusses the unique aspects of this pipeline and their influence on fracture control, reviews conventional fracture control design methods, their limitations with regard to the pipe in question, the extent to which they can be utilized for this project, and other approaches being explored. Test pipe of the size and grade required for the OIP show fracture toughness well in excess of the minimum requirements.

  2. All Along the Fractures

    NASA Image and Video Library

    2015-09-30

    This image from NASA Mars Reconnaissance Orbiter spacecraft provides information about erosion and movement of surface material, about wind and weather patterns, even about the soil grains and grain sizes. However, looking past the dunes, these images also reveal the nature of the substrate beneath. Within the spaces between the dunes, a resistant and highly fractured surface is revealed. The fractured ground is resistant to erosion by the wind, and suggests the material is bedrock that is now shattered by a history of bending stresses or temperature changes, such as cooling, for example. Alternately, the surface may be a sedimentary layer that was once wet and shrunk and fractured as it dried, like gigantic mud cracks. In either case, the relative small and indistinct fractures have trapped the dark dune sand marching overhead. Now the fractures have become quite distinct, allowing us to examine the orientation and spacing of the fractures to learn more about the processes that formed them. http://photojournal.jpl.nasa.gov/catalog/PIA19958

  3. Aluminum 2219-T87 and 5456-H116 - A comparative study of spacecraft wall materials in dual-wall structures under hypervelocity impact

    NASA Astrophysics Data System (ADS)

    Schonberg, William P.

    1992-11-01

    All earth-orbiting spacecraft are susceptible to high-speed impacts by pieces of orbital debris. To prevent mission failure and possibly loss of life, protection against perforation by high-speed orbital debris particles must be included in the spacecraft design. Although any number of materials can be used to manufacture perforation-resistant structures, aluminum is often used in such systems because of its relatively high strength-to-weight ratio. This paper presents the results of a study in which the high speed impact response characteristics of dual-wall structures made from two different aluminum alloys were analyzed to determine which alloy would be more suitable for use in a perforation-resistant dual-wall structural system that is to be exposed to the orbital debris environment. Impact response characteristics were obtained numerically and experimentally. At impact speeds below 7 km/s, it was found that the two aluminum alloys considered contributed similar levels of perforation resistance; at speeds in excess of 7 km/s, aluminum 2219-T87 was superior to aluminum 5546-H116 in preventing perforation of dual-wall structural systems.

  4. Aluminum 2219-T87 and 5456-H116 - A comparative study of spacecraft wall materials in dual-wall structures under hypervelocity impact

    NASA Technical Reports Server (NTRS)

    Schonberg, William P.

    1992-01-01

    All earth-orbiting spacecraft are susceptible to high-speed impacts by pieces of orbital debris. To prevent mission failure and possibly loss of life, protection against perforation by high-speed orbital debris particles must be included in the spacecraft design. Although any number of materials can be used to manufacture perforation-resistant structures, aluminum is often used in such systems because of its relatively high strength-to-weight ratio. This paper presents the results of a study in which the high speed impact response characteristics of dual-wall structures made from two different aluminum alloys were analyzed to determine which alloy would be more suitable for use in a perforation-resistant dual-wall structural system that is to be exposed to the orbital debris environment. Impact response characteristics were obtained numerically and experimentally. At impact speeds below 7 km/s, it was found that the two aluminum alloys considered contributed similar levels of perforation resistance; at speeds in excess of 7 km/s, aluminum 2219-T87 was superior to aluminum 5546-H116 in preventing perforation of dual-wall structural systems.

  5. Nonlinear fracture mechanics-based analysis of thin wall cylinders

    NASA Technical Reports Server (NTRS)

    Brust, Frederick W.; Leis, Brian N.; Forte, Thomas P.

    1994-01-01

    This paper presents a simple analysis technique to predict the crack initiation, growth, and rupture of large-radius, R, to thickness, t, ratio (thin wall) cylinders. The method is formulated to deal both with stable tearing as well as fatigue mechanisms in applications to both surface and through-wall axial cracks, including interacting surface cracks. The method can also account for time-dependent effects. Validation of the model is provided by comparisons of predictions to more than forty full scale experiments of thin wall cylinders pressurized to failure.

  6. Treatment of traumatic infra orbital nerve paresthesia

    PubMed Central

    Lone, Parveen Akhter; Singh, R. K.; Pal, U. S.

    2012-01-01

    This study was done to find out the role of topiramate therapy in infraorbital nerve paresthesia after miniplate fixation in zygomatic complxex fractures. A total 2 cases of unilateral zygomatic complex fracture, 2-3 weeks old with infra orbital nerve paresthesia were slected. Open reduction and plating was done in frontozygomaticregion. Antiepileptic drug tab topiramate was given in therapeutic doses and dose was increased slowly until functional recovery was noticed. PMID:23833503

  7. Chest Wall Trauma.

    PubMed

    Majercik, Sarah; Pieracci, Fredric M

    2017-05-01

    Chest wall trauma is common, and contributes significantly to morbidity and mortality of trauma patients. Early identification of major chest wall and concomitant intrathoracic injuries is critical. Generalized management of multiple rib fractures and flail chest consists of adequate pain control (including locoregional modalities); management of pulmonary dysfunction by invasive and noninvasive means; and, in some cases, surgical fixation. Multiple studies have shown that patients with flail chest have substantial benefit (decreased ventilator and intensive care unit days, improved pulmonary function, and improved long-term functional outcome) when they undergo surgery compared with nonoperative management. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Fracture toughness testing on ferritic alloys using the electropotential technique

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

    Huang, F.H.; Wire, G.L.

    1981-06-11

    Fracture toughness measurements as done conventionally require large specimens (5 x 5 x 2.5 cm) which would be prohibitively expensive to irradiate over the fluence and temperature ranges required for first wall design. To overcome this difficulty a single specimen technique for J intergral fracture toughness measurements on miniature specimens (1.6 cm OD x 0.25 cm thick) was developed. Comparisons with specimens three times as thick show that the derived J/sub 1c/ is constant, validating the specimen for first wall applications. The electropotential technique was used to obtain continuous crack extension measurements, allowing a ductile fracture resistence curve to bemore » constructed from a single specimen. The irradiation test volume required for fracture toughness measurements using both miniature specimens and single specimen J measurements was reduced a factor of 320, making it possible to perform a systematic exploration of irradiation temperature and dose variables as required for qualification of HT-9 and 9Cr-1Mo base metal and welds for first wall application. Fracture toughness test results for HT-9 and 9Cr-1Mo from 25 to 539/sup 0/C are presented to illustrate the single specimen technique.« less

  9. Sinus involvement in inflammatory orbital pseudotumor.

    PubMed

    Eshaghian, J; Anderson, R L

    1981-04-01

    Orbital pseudotumor is a difficult diagnosis to establish preoperatively. The relationship between sinus disease and orbital pseudotumor is controversial. We describe two patients with unilateral proptosis, diplopia, palpable orbital masses, ocular discomfort, and sinus problems of short duration. Echographically, both had low reflective masses in the orbit and the adjacent sinuses. Roentgenograms and echograms were interpreted as showing erosion of the bony orbital wall. A presumptive diagnosis of sinus malignant neoplasm with orbital extension was made. Sinus histopathologic examination in one case and nasal histopathologic examination in the other showed chronic inflammatory changes compatible with the diagnosis of pseudotumor. At orbitotomy, one patient had vessels communicating between the orbital and sinus lesions, and both patients had irregular pitting of the bone next to the histologically proved orbital pseudotumors. The lytic erosive changes predicted preoperatively were not present. Simultaneous orbital and sinus pseudotumors seem to be a distinct clinicopathologic entity. Those concerned with the diagnosis and management of orbital disease should be aware of this entity.

  10. Origin and timing of Dauphiné twins in quartz cement in fractured sandstones from diagenetic environments: Insight from fluid inclusions

    NASA Astrophysics Data System (ADS)

    Fall, András; Ukar, Estibalitz; Laubach, Stephen E.

    2016-09-01

    Electron backscattered diffraction techniques (EBSD) show that Dauphiné twins in quartz are widespread in many tectonometamorphic environments. Our study documents that under diagenetic temperatures (< 200 °C) and burial depths < 5 km Dauphiné twins are common in isolated fracture quartz deposits spanning between fracture walls (i.e., quartz bridges) in low-porosity quartz-cemented sandstones. Using examples from East Texas and Colorado cores, we show that twins are associated with crack-seal microstructure and fluid inclusions. Fracture wall-parallel and wall-normal inclusion trails contain coexisting aqueous and hydrocarbon gas inclusions, so homogenization temperatures of aqueous inclusions record true trapping temperatures. Inclusions in alignments normal to fracture walls are large and irregularly shaped compared to those aligned parallel to walls, but both show similar liquid-to-vapor ratios. Stacking transmitted light images with scanning electron microscope cathodoluminescence (SEM-CL) and EBSD images demonstrates that Dauphiné twin boundaries are localized along wall-normal inclusion trails. Trapping temperatures for wall-normal inclusion trails are usually higher than those aligned parallel to the fracture wall. Wall-normal fluid inclusion assemblage temperatures typically match the highest temperatures of wall-parallel assemblages trapped during sequential widening, but not necessarily the most recent. In context of burial histories for these samples, this temperature pattern implies that wall-normal assemblages form at discrete times during or after crack-seal fracture widening. Localization in isolated, potentially high-stress quartz deposits in fractures is compatible with a mechanical origin for these Dauphiné twins. Punctuated temperature values and discrepant sizes and shapes of inclusions in wall-normal trails implies that twinning is a by-product of the formation of the wall-normal inclusion assemblages. The association of Dauphiné twins

  11. Bilateral orbital emphysema and pneumocephalus as a result of accidental compressed air exposure.

    PubMed

    Yuksel, Murvet; Yuksel, K Zafer; Ozdemir, Gokhan; Ugur, Tuncay

    2007-01-01

    Orbital emphysema is a rare condition in the absence of trauma or sinus disease. A 22-year-old man suffering from left orbital trauma due to sudden exposure to compressed air tube was admitted with severe pain in the left eye, swelling, and mild periorbital ecchymosis. Physical examination revealed a large conjunctival laceration in the left orbit. Multislice computed tomographic scanning of the head and orbits showed extensive radiolucencies consistent with the air in both orbits, more prominent in the left. There was also subcutaneous air in the left periorbital soft tissue extending through fronto-temporal and zygomatic areas. Air was also demonstrated adjacent to the left optic canal and within the subarachnoid space intracranially. There was no evidence of any orbital, paranasal sinus, or cranial fracture. Visual acuity was minimally decreased bilaterally. The conjunctiva was sutured under local anesthesia. After 3 weeks of follow-up, the patient completely recovered without visual loss. Bilateral orbital emphysema with pneumocephalus can occur from a high-pressure compressed air injury after unilateral conjunctival trauma without any evidence of fracture.

  12. Origins and nature of non-Fickian transport through fractures

    NASA Astrophysics Data System (ADS)

    Wang, L.; Cardenas, M. B.

    2014-12-01

    Non-Fickian transport occurs across all scales within fractured and porous geological media. Fundamental understanding and appropriate characterization of non-Fickian transport through fractures is critical for understanding and prediction of the fate of solutes and other scalars. We use both analytical and numerical modeling, including direct numerical simulation and particle tracking random walk, to investigate the origin of non-Fickian transport through both homogeneous and heterogeneous fractures. For the simple homogenous fracture case, i.e., parallel plates, we theoretically derived a formula for dynamic longitudinal dispersion (D) within Poiseuille flow. Using the closed-form expression for the theoretical D, we quantified the time (T) and length (L) scales separating preasymptotic and asymptotic dispersive transport, with T and L proportional to aperture (b) of parallel plates to second and fourth orders, respectively. As for heterogeneous fractures, the fracture roughness and correlation length are closely associated with the T and L, and thus indicate the origin for non-Fickian transport. Modeling solute transport through 2D rough-walled fractures with continuous time random walk with truncated power shows that the degree of deviation from Fickian transport is proportional to fracture roughness. The estimated L for 2D rough-walled fractures is significantly longer than that derived from the formula within Poiseuille flow with equivalent b. Moreover, we artificially generated normally distributed 3D fractures with fixed correlation length but different fracture dimensions. Solute transport through 3D fractures was modeled with a particle tracking random walk algorithm. We found that transport transitions from non-Fickian to Fickian with increasing fracture dimensions, where the estimated L for the studied 3D fractures is related to the correlation length.

  13. Trends in Orbital Decompression Techniques of Surveyed American Society of Ophthalmic Plastic and Reconstructive Surgery Members.

    PubMed

    Reich, Shani S; Null, Robert C; Timoney, Peter J; Sokol, Jason A

    To assess current members of the American Society of Ophthalmic Plastic and Reconstructive Surgery (ASOPRS) regarding preference in surgical techniques for orbital decompression in Graves' disease. A 10-question web-based, anonymous survey was distributed to oculoplastic surgeons utilizing the ASOPRS listserv. The questions addressed the number of years of experience performing orbital decompression surgery, preferred surgical techniques, and whether orbital decompression was performed in collaboration with an ENT surgeon. Ninety ASOPRS members participated in the study. Most that completed the survey have performed orbital decompression surgery for >15 years. The majority of responders preferred a combined approach of floor and medial wall decompression or balanced lateral and medial wall decompression; only a minority selected a technique limited to 1 wall. Those surgeons who perform fat decompression were more likely to operate in collaboration with ENT. Most surgeons rarely remove the orbital strut, citing risk of worsening diplopia or orbital dystopia except in cases of optic nerve compression or severe proptosis. The most common reason given for performing orbital decompression was exposure keratopathy. The majority of surgeons perform the surgery without ENT involvement, and number of years of experience did not correlate significantly with collaboration with ENT. The majority of surveyed ASOPRS surgeons prefer a combined wall approach over single wall approach to initial orbital decompression. Despite the technological advances made in the field of modern endoscopic surgery, no single approach has been adopted by the ASOPRS community as the gold standard.

  14. Rib fracture following stereotactic body radiotherapy: a potential pitfall.

    PubMed

    Stanic, Sinisa; Boike, Thomas P; Rule, William G; Timmerman, Robert D

    2011-11-01

    Although the incidence of rib fractures after conventional radiotherapy is generally low (<2%), rib fractures are a relatively common complication of stereotactic body radiotherapy. For malignancy adjacent to the chest wall, the incidence of rib fractures after stereotactic body radiotherapy is as high as 10%. Unrecognized bone fractures can mimic bone metastases on bone scintigraphy, can lead to extensive workup, and can even lead to consideration of unnecessary systemic chemotherapy, as treatment decisions can be based on imaging findings alone. Nuclear medicine physicians and diagnostic radiologists should always consider rib fracture in the differential diagnosis.

  15. Implications of Earth analogs to Martian sulfate-filled Fractures

    NASA Astrophysics Data System (ADS)

    Holt, R. M.; Powers, D. W.

    2017-12-01

    Sulfate-filled fractures in fine-grained sediments on Mars are interpreted to be the result of fluid movement during deep burial. Fractures in the Dewey Lake (aka Quartermaster) Formation of southeastern New Mexico and west Texas are filled with gypsum that is at least partially synsedimentary. Sulfate in the Dewey Lake takes two principal forms: gypsum cement and gypsum (mainly fibrous) that fills fractures ranging from horizontal to vertical. Apertures are mainly mm-scale, though some are > 1 cm. The gypsum is antitaxial, fibrous, commonly approximately perpendicular to the wall rock, and displays suture lines and relics of the wall rock. Direct evidence of synsedimentary, near-surface origin includes gypsum intraclasts, intraclasts that include smaller intraclasts that contain gypsum clasts, intraclasts of gypsum with suture lines, gypsum concentrated in small desiccation cracks, and intraclasts that include fibrous gypsum-filled fractures that terminate at the eroded clast boundary. Dewey Lake fracture fillings suggest that their Martian analogs may also have originated in the shallow subsurface, shortly following the deposition of Martian sediments, in the presence of shallow aquifers.

  16. Chest wall stabilization in trauma patients: why, when, and how?

    PubMed Central

    White, Thomas W.

    2018-01-01

    Blunt trauma to the chest wall and rib fractures are remarkably frequent and are the basis of considerable morbidity and possible mortality. Surgical remedies for highly displaced rib fractures, especially in cases of flail chest, have been undertaken intermittently for more than 50 years. Rib-specific plating systems have started to be used in the last 10 years. These have ushered in the modern era of rib repair with chest wall stabilization (CWS) techniques that are safer, easier to perform, and more efficient. Recent consensus statements have sought to define the indications and contraindications, as well as the when, the how, and the technical details of CWS. Repair should be considered for patients who have three or more displaced rib fractures or a flail chest, whether or not mechanical ventilation is required. Additional candidates include patients who fail non-operative management irrespective of fracture pattern and those with rib fractures who need thoracic procedures for other reasons. Traditionally, unstable spine fracture and severe traumatic brain injury are definite contraindications. Pulmonary contusion’s role in the decision to perform CWS remains controversial. A range of rib-specific plating systems are now commercially available. PMID:29744222

  17. Summary and interpretation of dye-tracer tests to investigate the hydraulic connection of fractures at a ridge-and-valley-wall site near Fishtrap Lake, Pike County, Kentucky

    USGS Publications Warehouse

    Taylor, Charles J.

    1994-01-01

    Dye-tracer tests were done during 1985-92 to investigate the hydraulic connection between fractures in Pennsylvanian coal-bearing strata at a ridge-and-valley-wall site near Fishtrap Lake, Pike County, Ky. Fluorescent dye was injected into a core hole penetrating near-surface and mining-induced fractures near the crest of the ridge. The rate and direction of migration of dye in the subsurface were determined by measuring the relative concentration of dye in water samples collected from piezometers completed in conductive fracture zones and fractured coal beds at various stratigraphic horizons within the ridge. Dye-concentration data and water-level measurements for each piezometer were plotted as curves on dye-recovery hydrographs. The dye-recovery hydrographs were used to evaluate trends in the fluctuation of dye concentrations and hydraulic heads in order to identify geologic and hydrologic factors affecting the subsurface transport of dye. The principal factors affecting the transport of dye in the subsurface hydrologic system were determined to be (1) the distribution, interconnection, and hydraulic properties of fractures; (2) hydraulic-head conditions in the near-fracture zone at the time of dye injection; and (3) subsequent short- and long-term fluctuations in recharge to the hydrologic system. In most of the dye-tracer tests, dye-recovery hydrographs are characterized by complex, multipeaked dye-concentration curves that are indicative of a splitting of dye flow as ground water moved through fractures. Intermittent dye pulses (distinct upward spikes in dye concentration) mark the arrivals of dye-labeled water to piezometers by way of discrete fracture-controlled flow paths that vary in length, complexity, and hydraulic conductivity. Dye injections made during relatively high- or increasinghead conditions resulted in rapid transport of dye (within several days or weeks) from near-surf ace fractures to piezometers. Injections made during relatively low- or

  18. HVI Ballistic Performance Characterization of Non-Parallel Walls

    NASA Technical Reports Server (NTRS)

    Bohl, William; Miller, Joshua; Christiansen, Eric

    2012-01-01

    The Double-Wall, "Whipple" Shield [1] has been the subject of many hypervelocity impact studies and has proven to be an effective shield system for Micro-Meteoroid and Orbital Debris (MMOD) impacts for spacecraft. The US modules of the International Space Station (ISS), with their "bumper shields" offset from their pressure holding rear walls provide good examples of effective on-orbit use of the double wall shield. The concentric cylinder shield configuration with its large radius of curvature relative to separation distance is easily and effectively represented for testing and analysis as a system of two parallel plates. The parallel plate double wall configuration has been heavily tested and characterized for shield performance for normal and oblique impacts for the ISS and other programs. The double wall shield and principally similar Stuffed Whipple Shield are very common shield types for MMOD protection. However, in some locations with many spacecraft designs, the rear wall cannot be modeled as being parallel or concentric with the outer bumper wall. As represented in Figure 1, there is an included angle between the two walls. And, with a cylindrical outer wall, the effective included angle constantly changes. This complicates assessment of critical spacecraft components located within outer spacecraft walls when using software tools such as NASA's BumperII. In addition, the validity of the risk assessment comes into question when using the standard double wall shield equations, especially since verification testing of every set of double wall included angles is impossible.

  19. Mapping Fractures in KAERI Underground Research Tunnel using Ground Penetrating Radar

    NASA Astrophysics Data System (ADS)

    Baek, Seung-Ho; Kim, Seung-Sep; Kwon, Jang-Soon

    2016-04-01

    The proportion of nuclear power in the Republic of Korea occupies about 40 percent of the entire electricity production. Processing or disposing nuclear wastes, however, remains one of biggest social issues. Although low- and intermediate-level nuclear wastes are stored temporarily inside nuclear power plants, these temporary storages can last only up to 2020. Among various proposed methods for nuclear waste disposal, a long-term storage using geologic disposal facilities appears to be most highly feasible. Geological disposal of nuclear wastes requires a nuclear waste repository situated deep within a stable geologic environment. However, the presence of small-scale fractures in bedrocks can cause serious damage to durability of such disposal facilities because fractures can become efficient pathways for underground waters and radioactive wastes. Thus, it is important to find and characterize multi-scale fractures in bedrocks hosting geologic disposal facilities. In this study, we aim to map small-scale fractures inside the KAERI Underground Research Tunnel (KURT) using ground penetrating radar (GPR). The KURT is situated in the Korea Atomic Energy Research Institute (KAERI). The survey target is a section of wall cut by a diamond grinder, which preserves diverse geologic features such as dykes. We conducted grid surveys on the wall using 500 MHz and 1000 MHz pulseEKKO PRO sensors. The observed GPR signals in both frequencies show strong reflections, which are consistent to form sloping planes. We interpret such planar features as fractures present in the wall. Such fractures were also mapped visually during the development of the KURT. We confirmed their continuity into the wall from the 3D GPR images. In addition, the spatial distribution and connectivity of these fractures are identified from 3D subsurface images. Thus, we can utilize GPR to detect multi-scale fractures in bedrocks, during and after developing underground disposal facilities. This study was

  20. Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors.

    PubMed

    Nambu, Atsushi; Onishi, Hiroshi; Aoki, Shinichi; Tominaga, Licht; Kuriyama, Kengo; Araya, Masayuki; Saito, Ryoh; Maehata, Yoshiyasu; Komiyama, Takafumi; Marino, Kan; Koshiishi, Tsuyota; Sawada, Eiichi; Araki, Tsutomu

    2013-02-07

    As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1-10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients.

  1. Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors

    PubMed Central

    2013-01-01

    Background As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated. Methods Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1–10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio. Results Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy. Conclusions Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients. PMID:23391264

  2. Percolation and permeability of fracture networks in Excavated Damaged Zones

    NASA Astrophysics Data System (ADS)

    Mourzenko, V.; Thovert, J.; Adler, P. M.

    2012-12-01

    Generally, the excavation process of a gallery generates fractures in its immediate vicinity. The corresponding zone which is called the Excavated Damaged Zone (EDZ), has a larger permeability than the intact surrounding medium. The properties of the EDZ are attracting more and more attention because of their potential importance in repositories of nuclear wastes. The EDZ which is induced by the excavation process may create along the galleries of the repositories a high permeability zone which could directly connect the storage area with the ground surface. Therefore, the studies of its properties are of crucial importance for applications such as the storage of nuclear wastes. Field observations (such as the ones which have been systematically performed at Mont Terri by [1, 2]) suggest that the fracture density is an exponentially decreasing function of the distance to the wall with a characteristic length of about 0.5 m and that the fracture orientation is anisotropic (most fractures are subparallel to the tunnel walls) and well approximated by a Fisher law whose pole is orthogonal to the wall. Numerical samples are generated according to these prescriptions. Their percolation status and hydraulic transmissivity can be calculated by the numerical codes which are detailed in [3]. Percolation is determined by a pseudo diffusion algorithm. Flow determination necessitates the meshing of the fracture networks and the discretisation of the Darcy equation by a finite volume technique; the resulting linear system is solved by a conjugate gradient algorithm. Only the flow properties of the EDZ along the directions which are parallel to the wall are of interest when a pressure gradient parallel to the wall is applied. The transmissivity T which relates the total flow rate per unit width Q along the wall through the whole EDZ to the pressure gradient grad p, is defined by Q = - T grad p/mu where mu is the fluid viscosity. The percolation status and hydraulic transmissivity

  3. Flank pseudohernia following posterior rib fracture: a case report.

    PubMed

    Butensky, Adam M; Gruss, Leah P; Gleit, Zachary L

    2016-10-01

    A pseudohernia is an abdominal wall bulge that may be mistaken for a hernia but that lacks the disruption of the abdominal wall that characterizes a hernia. Thus, the natural history and treatment of this condition differ from those of a hernia. This is the first report of a pseudohernia due to cough-associated rib fracture. A case of pseudohernia due to fractures of the 10 th and 11 th ribs in a 68-year-old white woman is presented. The patient suffered from a major coughing episode 1 year prior to her presentation, after which she noted a progressively enlarging bulge in her left flank. Computed tomography demonstrated a bulge in the abdominal wall containing bowel and spleen but with all muscle and fascial layers intact; in addition, lateral 10 th rib and posterior 11 th rib fractures were noted. As there was no defect in muscle or fascia, we diagnosed a pseudohernia, likely due to a denervation injury from the fractured ribs. Symptomatic treatment was recommended, including wearing a corset and referral to a pain management clinic. Symptomatic treatment is thought to be the mainstay of therapy for pseudohernias, as surgical intervention is unlikely to be of benefit.

  4. CONTAMINANT TRANSPORT IN PARALLEL FRACTURED MEDIA: SUDICKY AND FRIND REVISITED

    EPA Science Inventory

    This paper is concerned with a modified, nondimensional form of the parallel fracture, contaminant transport model of Sudicky and Frind (1982). The modifications include the boundary condition at the fracture wall, expressed by a parameter, and the power-law relationship between...

  5. CONTAMINANT TRANSPORT IN PARALLEL FRACTURED MEDIA: SUDICKY AND FRIND REVISITED

    EPA Science Inventory

    This paper is concerned with a modified, nondimensional form of the parallel fracture, contaminant transport model of Sudicky and Frind (1982). The modifications include the boundary condition at the fracture wall, expressed by a parameter , and the power-law relationship betwe...

  6. Detail view of the starboard mid deck wall of the ...

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

    Detail view of the starboard mid deck wall of the Orbiter Discovery showing Operational Sleeping Bags attached horizontally to the wall for the crew sleep period. If it is required as part of a mission's manifest a four-tiered rigid sleep station can be installed. This photograph was taken at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  7. The impact of suction drainage on orbital compartment syndrome after craniofacial surgery.

    PubMed

    Fenzl, Carlton R; Golio, Dominick

    2014-07-01

    Postoperative orbital compartment syndrome is a potentially blinding complication of surgery in the orbital region. We describe the technique of orbital drain placement as a method of preventing vision loss resulting from orbital compartment syndrome. We present a retrospective case series of 29 patients who underwent orbital fracture, facial fracture, and orbital implant removal from 7/4/2008 to 5/3/2013 by the same craniofacial surgeon. An orbital drain was placed in each patient. The drainage was recorded daily until drain removal. Criteria for removal included less than or equal to 5 mL of drainage in 24 hours. Of the 29 patients included in this study, 21 were men and 8 were women. Ages ranged from 17 to 67 years. The postoperative drainage ranged from less than 1 mL to 71 mL of serosanguinous fluid. All drains were removed between the first and sixth postoperative days. No postoperative visual loss, infections, or additional antibiotics were recorded with follow-up reaching as far as 40 months. Postoperative orbital compartment syndrome is a dangerous complication of surgery in the orbital region. Its rapid onset necessitates immediate intervention to prevent permanent vision loss. Morphologic changes to the optic nerve as well as reductions in electroretinogram a- and b-wave amplitudes have been demonstrated with as little as 7 mL of fluid accumulation. Intraoperative orbital drain placement should be considered in all patients undergoing surgery in the orbital region as a preventative measure.

  8. Transport of Particle Swarms Through Fractures

    NASA Astrophysics Data System (ADS)

    Boomsma, E.; Pyrak-Nolte, L. J.

    2011-12-01

    The transport of engineered micro- and nano-scale particles through fractured rock is often assumed to occur as dispersions or emulsions. Another potential transport mechanism is the release of particle swarms from natural or industrial processes where small liquid drops, containing thousands to millions of colloidal-size particles, are released over time from seepage or leaks. Swarms have higher velocities than any individual colloid because the interactions among the particles maintain the cohesiveness of the swarm as it falls under gravity. Thus particle swarms give rise to the possibility that engineered particles may be transported farther and faster in fractures than predicted by traditional dispersion models. In this study, the effect of fractures on colloidal swarm cohesiveness and evolution was studied as a swarm falls under gravity and interacts with fracture walls. Transparent acrylic was used to fabricate synthetic fracture samples with either (1) a uniform aperture or (2) a converging aperture followed by a uniform aperture (funnel-shaped). The samples consisted of two blocks that measured 100 x 100 x 50 mm. The separation between these blocks determined the aperture (0.5 mm to 50 mm). During experiments, a fracture was fully submerged in water and swarms were released into it. The swarms consisted of dilute suspensions of either 25 micron soda-lime glass beads (2% by mass) or 3 micron polystyrene fluorescent beads (1% by mass) with an initial volume of 5μL. The swarms were illuminated with a green (525 nm) LED array and imaged optically with a CCD camera. In the uniform aperture fracture, the speed of the swarm prior to bifurcation increased with aperture up to a maximum at a fracture width of approximately 10 mm. For apertures greater than ~15 mm, the velocity was essentially constant with fracture width (but less than at 10 mm). This peak suggests that two competing mechanisms affect swarm velocity in fractures. The wall provides both drag, which

  9. Inferring biological evolution from fracture patterns in teeth.

    PubMed

    Lawn, Brian R; Bush, Mark B; Barani, Amir; Constantino, Paul J; Wroe, Stephen

    2013-12-07

    It is hypothesised that specific tooth forms are adapted to resist fracture, in order to accommodate the high bite forces needed to secure, break down and consume food. Three distinct modes of tooth fracture are identified: longitudinal fracture, where cracks run vertically between the occlusal contact and the crown margin (or vice versa) within the enamel side wall; chipping fracture, where cracks run from near the edge of the occlusal surface to form a spall in the enamel at the side wall; and transverse fracture, where a crack runs horizontally through the entire section of the tooth to break off a fragment and expose the inner pulp. Explicit equations are presented expressing critical bite force for each fracture mode in terms of characteristic tooth dimensions. Distinctive transitions between modes occur depending on tooth form and size, and loading location and direction. Attention is focussed on the relatively flat, low-crowned molars of omnivorous mammals, including humans and other hominins and the elongate canines of living carnivores. At the same time, allusion to other tooth forms - the canines of the extinct sabre-tooth (Smilodon fatalis), the conical dentition of reptiles, and the columnar teeth of herbivores - is made to highlight the generality of the methodology. How these considerations impact on dietary behaviour in fossil and living taxa is discussed. © 2013 Elsevier Ltd. All rights reserved.

  10. Origin and Timing of Dauphiné Twins Using Fluid Inclusions in Quartz-Cement Fractures in Sandstones from Diagenetic Environments

    NASA Astrophysics Data System (ADS)

    Fall, A.; Ukar, E.; Laubach, S.

    2016-12-01

    Dauphiné twins in quartz are widespread in many tectonometamorphic environments. Under diagenetic temperatures (<200°C) and burial depths less than 5 km Dauphiné twins are also common in isolated fracture quartz deposits spanning between fracture walls in low-porosity quartz-cemented sandstones. The twin boundaries coincide with fracture wall-normal fluid inclusion trails. The association of Dauphiné twins and fluid inclusion trails from which temperature and possibly timing can be inferred provides a way to research mechanism and timing of twinning, and potentially the magnitude of paleostrain and stress in some diagenetic settings. Using examples from East Texas and Colorado cores, we show that twins are associated with crack-seal microstructure and fluid inclusions. Fracture wall-parallel and wall-normal inclusion trails contain coexisting aqueous and hydrocarbon gas inclusions, so homogenization temperatures of aqueous inclusions, ranging from 130°C to 159°C in the East Texas Basin, and from 162°C to 176°C in the Piceance Basin, record true trapping temperatures. Inclusions in wall-normal trails are large and irregularly shaped compared to those in wall-parallel trails, but both show similar liquid-to-vapor ratios. Trapping temperatures for wall-normal inclusion trails are usually higher than those in the wall-parallel trails. Wall-normal fluid inclusion assemblage temperatures typically match the highest temperatures of wall-parallel assemblages trapped during sequential widening, but not necessarily the most recent. In context of burial histories for these samples, this temperature pattern implies that wall-normal assemblages form at discrete times during or after crack-seal fracture widening. Stacking transmitted light images with scanning electron microscope cathodoluminescence (SEM-CL) and electron backscattered diffraction (EBSD) images demonstrates that the twin boundaries are localized along wall-normal inclusion trails. Localization in isolated

  11. Cosmic bubble and domain wall instabilities II: fracturing of colliding walls

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

    Braden, Jonathan; Bond, J. Richard; Mersini-Houghton, Laura, E-mail: j.braden@ucl.ac.uk, E-mail: bond@cita.utoronto.ca, E-mail: mersini@physics.unc.edu

    2015-08-01

    We study collisions between nearly planar domain walls including the effects of small initial nonplanar fluctuations. These perturbations represent the small fluctuations that must exist in a quantum treatment of the problem. In a previous paper, we demonstrated that at the linear level a subset of these fluctuations experience parametric amplification as a result of their coupling to the planar symmetric background. Here we study the full three-dimensional nonlinear dynamics using lattice simulations, including both the early time regime when the fluctuations are well described by linear perturbation theory as well as the subsequent stage of fully nonlinear evolution. Wemore » find that the nonplanar fluctuations have a dramatic effect on the overall evolution of the system. Specifically, once these fluctuations begin to interact nonlinearly the split into a planar symmetric part of the field and the nonplanar fluctuations loses its utility. At this point the colliding domain walls dissolve, with the endpoint of this being the creation of a population of oscillons in the collision region. The original (nearly) planar symmetry has been completely destroyed at this point and an accurate study of the system requires the full three-dimensional simulation.« less

  12. Cosmic bubble and domain wall instabilities II: fracturing of colliding walls

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

    Braden, Jonathan; Department of Physics, University of Toronto,60 St. George Street, Toronto, ON, M5S 3H8; Department of Physics and Astronomy, University College London,Gower Street, London, WC1E 6BT

    2015-08-26

    We study collisions between nearly planar domain walls including the effects of small initial nonplanar fluctuations. These perturbations represent the small fluctuations that must exist in a quantum treatment of the problem. In a previous paper, we demonstrated that at the linear level a subset of these fluctuations experience parametric amplification as a result of their coupling to the planar symmetric background. Here we study the full three-dimensional nonlinear dynamics using lattice simulations, including both the early time regime when the fluctuations are well described by linear perturbation theory as well as the subsequent stage of fully nonlinear evolution. Wemore » find that the nonplanar fluctuations have a dramatic effect on the overall evolution of the system. Specifically, once these fluctuations begin to interact nonlinearly the split into a planar symmetric part of the field and the nonplanar fluctuations loses its utility. At this point the colliding domain walls dissolve, with the endpoint of this being the creation of a population of oscillons in the collision region. The original (nearly) planar symmetry has been completely destroyed at this point and an accurate study of the system requires the full three-dimensional simulation.« less

  13. Cough-induced rib fractures.

    PubMed

    Hanak, Viktor; Hartman, Thomas E; Ryu, Jay H

    2005-07-01

    To define the demographic, clinical, and radiological features of patients with cough-induced rib fractures and to assess potential risk factors. For this retrospective, single-center study, we identified all cases of cough-induced rib fractures diagnosed at the Mayo Clinic in Rochester, Minn, over a 9-year period between January 1, 1996, and January 31, 2005. Bone densitometry data from patients' medical records were analyzed, and T scores were used to classify patients into bone density categories. The mean +/- SD age of the 54 study patients at presentation was 55+/-17 years, and 42 patients (78%) were female. Patients presented with chest wall pain after onset of cough. Rib fracture was associated with chronic cough (> or =3 weeks' duration) in 85% of patients. Rib fractures were documented by chest radiography, rib radiography, computed tomography, or bone scan. Chest radiography had been performed in 52 patients and revealed rib fracture in 30 (58%). There were 112 fractured ribs in 54 patients. One half of patients had more than one fractured rib. Right-sided rib fractures alone were present in 17 patients (26 fractured ribs), left-sided in 23 patients (35 fractured ribs), and bilateral in 14 patients (51 fractured ribs). The most commonly fractured rib on both sides was rib 6. The fractures were most common at the lateral aspect of the rib cage. Bone densitometry was done in 26 patients and revealed osteopenia or osteoporosis in 17 (65%). Cough-induced rib fractures occur primarily in women with chronic cough. Middle ribs along the lateral aspect of the rib cage are affected most commonly. Although reduced bone density is likely a risk factor, cough-induced rib fractures can occur in the presence of normal bone density.

  14. Low-Cost 3D Printing Orbital Implant Templates in Secondary Orbital Reconstructions.

    PubMed

    Callahan, Alison B; Campbell, Ashley A; Petris, Carisa; Kazim, Michael

    Despite its increasing use in craniofacial reconstructions, three-dimensional (3D) printing of customized orbital implants has not been widely adopted. Limitations include the cost of 3D printers able to print in a biocompatible material suitable for implantation in the orbit and the breadth of available implant materials. The authors report the technique of low-cost 3D printing of orbital implant templates used in complex, often secondary, orbital reconstructions. A retrospective case series of 5 orbital reconstructions utilizing a technique of 3D printed orbital implant templates is presented. Each patient's Digital Imaging and Communications in Medicine data were uploaded and processed to create 3D renderings upon which a customized implant was designed and sent electronically to printers open for student use at our affiliated institutions. The mock implants were sterilized and used intraoperatively as a stencil and mold. The final implant material was chosen by the surgeons based on the requirements of the case. Five orbital reconstructions were performed with this technique: 3 tumor reconstructions and 2 orbital fractures. Four of the 5 cases were secondary reconstructions. Molded Medpor Titan (Stryker, Kalamazoo, MI) implants were used in 4 cases and titanium mesh in 1 case. The stenciled and molded implants were adjusted no more than 2 times before anchored in place (mean 1). No case underwent further revision. The technique and cases presented demonstrate 1) the feasibility and accessibility of low-cost, independent use of 3D printing technology to fashion patient-specific implants in orbital reconstructions, 2) the ability to apply this technology to the surgeon's preference of any routinely implantable material, and 3) the utility of this technique in complex, secondary reconstructions.

  15. Crustal Fractures of Ophir Planum

    NASA Technical Reports Server (NTRS)

    2002-01-01

    (Released 29 April 2002) The Science This THEMIS image covers a tract of plateau territory called Ophir Planum. The most obvious features in this scene are the fractures (ranging from 1 to 5 km wide) running from the upper left to lower right. Localized rifting and deep-seated tension fracturing of the crust probably formed these cracks. The wall rock displayed in the upper part of the cliffs appears to be layered. The southwest-facing wall of the largest and uppermost fracture has classic spur and gully topography. This type of topography is created by differing amounts of erosion. Also seen in this image are some scattered impact craters and some dark wind streaks in the lower right. The Ophir Planum plateau separates two separate smaller canyon systems, not visible in this image, (Candor Chasma to the north and Melas Chasma to the south) in the Valles Marineris canyon complex. The whole Valles Marineris canyon system extends some 4,000 km across the equatorial realms of Mars. For comparison, this would stretch from New York City to San Francisco. The Story Plateaus and spurs might make you think of cowboys on the open plain. 'Spurs' in this context, however, are simply ridges that can be seen on the side of the southwest-facing wall of the large fracture that splits the terrain. Gullies stretch down this slope as well. Both of these features are caused by erosion, which is a mild force of change compared to whatever tension cracked the crust and ripped apart the land. The wall rock displayed in the upper part of the cliffs appears to be layered, suggesting that different kinds of rocks and minerals can be found in each banded zone. The Ophir Planum plateau separates two separate canyon systems in the Valles Marineris complex, the largest canyon in the solar system. If Valles Marineris were on Earth, it would stretch from New York City all the way to San Francisco. That will give you some idea of the geological forces that have acted upon the planet over time

  16. Wall Shear Stress, Wall Pressure and Near Wall Velocity Field Relationships in a Whirling Annular Seal

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Winslow, Robert B.; Thames, H. Davis, III

    1996-01-01

    The mean and phase averaged pressure and wall shear stress distributions were measured on the stator wall of a 50% eccentric annular seal which was whirling in a circular orbit at the same speed as the shaft rotation. The shear stresses were measured using flush mounted hot-film probes. Four different operating conditions were considered consisting of Reynolds numbers of 12,000 and 24,000 and Taylor numbers of 3,300 and 6,600. At each of the operating conditions the axial distribution (from Z/L = -0.2 to 1.2) of the mean pressure, shear stress magnitude, and shear stress direction on the stator wall were measured. Also measured were the phase averaged pressure and shear stress. These data were combined to calculate the force distributions along the seal length. Integration of the force distributions result in the net forces and moments generated by the pressure and shear stresses. The flow field inside the seal operating at a Reynolds number of 24,000 and a Taylor number of 6,600 has been measured using a 3-D laser Doppler anemometer system. Phase averaged wall pressure and wall shear stress are presented along with phase averaged mean velocity and turbulence kinetic energy distributions located 0.16c from the stator wall where c is the seal clearance. The relationships between the velocity, turbulence, wall pressure and wall shear stress are very complex and do not follow simple bulk flow predictions.

  17. Persistent Spin Current in a Hard-Wall Confining Quantum Wire with Weak Dresselhaus Spin-Orbit Coupling

    NASA Astrophysics Data System (ADS)

    Fu, Xi; Zhou, Guang-Hui

    2009-02-01

    We investigate theoretically the spin current in a quantum wire with weak Dresselhaus spin-orbit coupling connected to two normal conductors. Both the quantum wire and conductors are described by a hard-wall confining potential. Using the electron wave-functions in the quantum wire and a new definition of spin current, we have calculated the elements of linear spin current density js,xiT and js,yiT (i = x, y, z). We find that the elements jTs,xx and jTs,yy have a antisymmetrical relation and the element jTs,yz has the same amount level as js,xxT and js,yyT. We also find a net linear spin current density, which has peaks at the center of quantum wire. The net linear spin current can induce a linear electric field, which may imply a way of spin current detection.

  18. Experimental Hydromechanical Characterization and Numerical Modelling of a Fractured and Porous Sandstone

    NASA Astrophysics Data System (ADS)

    Souley, Mountaka; Lopez, Philippe; Boulon, Marc; Thoraval, Alain

    2015-05-01

    The experimental device previously used to study the hydromechanical behaviour of individual fractures on a laboratory scale, was adapted to make it possible to measure flow through porous rock mass samples in addition to fracture flows. A first series of tests was performed to characterize the hydromechanical behaviour of the fracture individually as well as the porous matrix (sandstone) comprising the fracture walls. A third test in this series was used to validate the experimental approach. These tests showed non-linear evolution of the contact area on the fracture walls with respect to effective normal stress. Consequently, a non-linear relationship was noted between the hydraulic aperture on the one hand, and the effective normal stress and mechanical opening on the other hand. The results of the three tests were then analysed by numerical modelling. The VIPLEF/HYDREF numerical codes used take into account the dual-porosity of the sample (fracture + rock matrix) and can be used to reproduce hydromechanical loading accurately. The analyses show that the relationship between the hydraulic aperture of the fracture and the mechanical closure has a significant effect on fracture flow rate predictions. By taking simultaneous measurements of flow in both fracture and rock matrix, we were able to carry out a global evaluation of the conceptual approach used.

  19. NASGRO(registered trademark): Fracture Mechanics and Fatigue Crack Growth Analysis Software

    NASA Technical Reports Server (NTRS)

    Forman, Royce; Shivakumar, V.; Mettu, Sambi; Beek, Joachim; Williams, Leonard; Yeh, Feng; McClung, Craig; Cardinal, Joe

    2004-01-01

    This viewgraph presentation describes NASGRO, which is a fracture mechanics and fatigue crack growth analysis software package that is used to reduce risk of fracture in Space Shuttles. The contents include: 1) Consequences of Fracture; 2) NASA Fracture Control Requirements; 3) NASGRO Reduces Risk; 4) NASGRO Use Inside NASA; 5) NASGRO Components: Crack Growth Module; 6) NASGRO Components:Material Property Module; 7) Typical NASGRO analysis: Crack growth or component life calculation; and 8) NASGRO Sample Application: Orbiter feedline flowliner crack analysis.

  20. 3D surgical printing and pre contoured plates for acetabular fractures.

    PubMed

    Chana-Rodríguez, Francisco; Mañanes, Rubén Pérez; Rojo-Manaute, José; Gil, Pablo; Martínez-Gómiz, José María; Vaquero-Martín, Javier

    2016-11-01

    We describe the methodical and possibilities of 3D surgical printing in preoperative planning of acetabular fractures showing a case of a 45-year-old with an associated transverse fracture of the left acetabulum with posterior wall fracture, with multiple fragments, and posterior ipsilateral hip dislocation, defending the do it your-self mode. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Reliability and smallest real difference of the ankle lunge test post ankle fracture.

    PubMed

    Simondson, David; Brock, Kim; Cotton, Susan

    2012-02-01

    This study aimed to determine the reliability and the smallest real difference of the Ankle Lunge test in an ankle fracture patient population. In the post immobilisation stage of ankle fracture, ankle dorsiflexion is an important measure of progress and outcome. The Ankle Lunge test measures weight bearing dorsiflexion, resulting in negative scores (knee to wall distance) and positive scores (toe to wall distance), for which the latter has proven reliability in normal subjects only. A consecutive sample of ankle fracture patients with permission to commence weight bearing, were recruited to the study. Three measurements of the Ankle Lunge Test were performed each by two raters, one senior and one junior physiotherapist. These occurred prior to therapy sessions in the second week after plaster removal. A standardised testing station was utilised and allowed for both knee to wall distance and toe to wall distance measurement. Data was collected from 10 individuals with ankle fracture, with an average age of 36 years (SD 14.8). Seventy seven percent of observations were negative. Intra and inter-rater reliability yielded intra class correlations at or above 0.97, p < .001. There was a significant systematic bias towards improved scores during repeated measurement for one rater (p = .01). The smallest real difference was calculated as 13.8mm. The Ankle Lunge test is a practical and reliable tool for measuring weightbearing dorsiflexion post ankle fracture. Copyright © 2011 Elsevier Ltd. All rights reserved.

  2. Influence of remaining coronal tooth structure on fracture resistance and failure mode of restored endodontically treated maxillary incisors.

    PubMed

    Santos Pantaleón, Domingo; Morrow, Brian R; Cagna, David R; Pameijer, Cornelis H; Garcia-Godoy, Franklin

    2018-03-01

    Limited information is available on the effect of an incomplete ferrule because of the varying residual axial wall heights and the volume of residual tooth structure on the fracture resistance of endodontically treated and restored maxillary incisors. The purpose of this in vitro investigation was to examine the effect of varying residual axial wall heights, residual coronal tooth structure, and the absence of 1 proximal axial wall on the fracture resistance and failure mode of endodontically treated teeth restored with metal posts. Sixty intact human maxillary central incisors were divided into 6 groups (n=10): no ferrule (NF), 2-mm complete ferrule (CF2), 2-mm (IF2), 3-mm (IF3), and 4-mm (IF4) incomplete ferrules missing a single interproximal wall, and a control group that had a 6-mm incomplete ferrule (IF6). Cast metal post-and-cores were placed in all experimental specimens except for controls. Control specimens received 1 interproximal cavity preparation extending to the root canal access and a composite resin restoration. Complete metal crowns were then cemented on all specimens. Completed specimens were subjected to thermocycling (6000 cycles, 5°C/55°C) followed by the immediate testing of fracture resistance. Failed specimens were sectioned buccolingually and evaluated to identify the failure mode. The data were analyzed with an analysis of variance (ANOVA) and the Student-Newman-Keuls multiple comparison test (α=.05). An incomplete ferrule (IF2) with 1 interproximal wall missing had significantly reduced fracture resistance (697 N) compared with a complete ferrule (932 N). An increase of 3 to 4 mm of remaining wall height improved fracture resistance, from 844 N (IF3) to 853 N (IF4). Partial decementation was noticed in 8 NF and 5 IF2 specimens. IF3 and IF4 had no decementations. Radicular fractures and cracks (catastrophic failure) were observed in all IF2, IF3, and IF4, 9 CF2, and 6 NF specimens. In 7 specimens without posts (IF6, control

  3. Indications for surgical stabilization of rib fractures in patients without flail chest: surveyed opinions of members of the Chest Wall Injury Society.

    PubMed

    Pieracci, Fredric M; Agarwal, Suresh; Doben, Andrew; Shiroff, Adam; Lottenberg, Larwence; Whitbeck, Sarah Ann; White, Thomas W

    2018-02-01

    There are currently no evidence-based indications for surgical stabilization of rib fractures (SSRF) in patients without flail chest. The purpose of this survey was to identify patients for whom there is relative equipoise (operative vs. non-operative) in order to assist in designing a randomized clinical trial. Members of the Chest Wall Injury Society were sent an online survey, in which 18 patient scenarios were presented. The baseline patient had ≥ three displaced, contiguous fractures and had no other contraindications for surgery. This default scenario was then varied based upon patient age, degree of traumatic brain injury (TBI), fracture series location, and number of abnormal pulmonary physiologic variables (oxygen requirement, respiratory rate, incentive spirometry ability, cough, and numeric pain score). Thirty respondents provided a total of 540 answers. Overall, the majority of responses were in favor of SSRF (n = 413, 84.1%). Furthermore, the vast majority of responses indicated that some degree of pulmonary compromise was necessary to recommend SSRF (n = 44, 90.4%), with ≥ two abnormal parameters being the most common threshold (n = 156, 31.8%). Decision to recommend SSRF varied significantly by number of abnormal clinical variables, age, and degree of TBI, but not by fracture series location. Patients aged 85 years old and those with moderate TBI were the least likely to be recommended for SSRF, regardless of abnormal pulmonary physiologic variables. The most appropriate cutoff for equipoise appeared to be a patient aged 21-79 years old, with no or mild TBI, ≥ two abnormal pulmonary parameters, and regardless of fracture location (44.8% consensus for SSRF). SSRF was recommended for most patients with non-flail, displaced rib fractures. However, this recommendation was contingent upon patient age, degree of TBI, and pulmonary clinical status. Results of this survey may be used to inform inclusion criteria for a future randomized

  4. Fracture modes in human teeth.

    PubMed

    Lee, J J-W; Kwon, J-Y; Chai, H; Lucas, P W; Thompson, V P; Lawn, B R

    2009-03-01

    The structural integrity of teeth under stress is vital to functional longevity. We tested the hypothesis that this integrity is limited by fracture of the enamel. Experiments were conducted on molar teeth, with a metal rod loaded onto individual cusps. Fracture during testing was tracked with a video camera. Two longitudinal modes of cracking were observed: median cracking from the contact zone, and margin cracking along side walls. Median cracks initiated from plastic damage at the contact site, at first growing slowly and then accelerating to the tooth margin. Margin cracks appeared to originate from the cemento-enamel junction, and traversed the tooth wall adjacent to the loaded cusp from the gingival to the occlusal surface. All cracks remained confined within the enamel shell up to about 550 N. At higher loads, additional crack modes--such as enamel chipping and delamination--began to manifest themselves, leading to more comprehensive failure of the tooth structure.

  5. Surgical Stabilization of Costoclavicular Injuries - A Combination of Flail Chest Injuries and a Clavicula Fracture.

    PubMed

    Langenbach, Andreas; Pinther, Melina; Krinner, Sebastian; Grupp, Sina; Ekkernkamp, Axel; Hennig, Friedrich F; Schulz-Drost, Stefan

    2017-01-01

    Background: Flail chest injuries (FCI) are associated with a high morbidity and mortality rate. As a concomitant clavicle fracture in FCI even worsens the outcome, the question is how can those costoclavicular injuries (CCI) be managed surgically. Methods: 11 patients with CCI were surgically treated by a locked plate osteosynthesis of the Clavicle and the underlying ribs through limited surgical approaches under general anesthesia. Patients were followed up after 2, 6, 12, 26 and 52 weeks. Results: All patients showed severe chest wall deformity due to severely displaced fractures of the ribs and the clavicle. They were suffering from pain and restriction of respiratory movements. The chest wall could be restored to normal shape in all cases with uneventful bone healing and a high patient convenience. Fractures of the clavicle and the second rib were managed through an innovative clavipectoral approach, the others through standard approaches to the anterolateral and the posterolateral chest wall. Two patients complained about numbness around the lateral approach and lasting periscapular pain. Conclusions: Surgical stabilization might be the appropriate therapy in CCI with dislocated fractures since they would cause severe deformity and loss of function of the chest wall and the shoulder. Celsius.

  6. Rib fracture repair: indications, technical issues, and future directions.

    PubMed

    Nirula, Raminder; Diaz, Jose J; Trunkey, Donald D; Mayberry, John C

    2009-01-01

    Rib fracture repair has been performed at selected centers around the world for more than 50 years; however, the operative indications have not been established and are considered controversial. The outcome of a strictly nonoperative approach may not be optimal. Potential indications for rib fracture repair include flail chest, painful, movable rib fractures refractory to conventional pain management, chest wall deformity/defect, rib fracture nonunion, and during thoracotomy for other traumatic indication. Rib fracture repair is technically challenging secondary to the human rib's relatively thin cortex and its tendency to fracture obliquely. Nonetheless, several effective repair systems have been developed. Future directions for progress on this important surgical problem include the development of minimally invasive techniques and the conduct of multicenter, randomized trials.

  7. Domain-wall motion at an ultrahigh speed driven by spin-orbit torque in synthetic antiferromagnets.

    PubMed

    Yu, Ziyang; Zhang, Yue; Zhang, Zhenhua; Cheng, Ming; Lu, Zhihong; Yang, Xiaofei; Shi, Jing; Xiong, Rui

    2018-04-27

    In this article, we present our numerical investigation about the spin-orbit-torque induced domain-wall (DW) motion in a synthetic antiferromagnetic multilayer nanotrack. This nanotrack was composed by two ferromagnetic (FM) layers with a RKKY inter-layer antiferromagnetic (AFM) exchange coupling. The velocity of DW was well manipulated by varying parameters including inter-layer exchange constant, the Dzyaloshinskii-Moriya interaction (DMI) strength, the current density and the magnetic anisotropy. The DW velocity was found to be strictly related to the orientation of the moments in the two FM layers. When the interlayer exchange constant or the DMI constant were larger than a critical value, there was a large angle between the moments in one FM layer and that in the other one under the current, and the DW was driven to move at an ultrahigh speed (around 10 000 m s -1 ). However, when the DMI or the AFM exchange coupling was weaker than the critical value, the moments in one FM layer were parallel to that in the other one under the current, and the velocity was significantly reduced.

  8. Coblation vertebroplasty for complex vertebral insufficiency fractures.

    PubMed

    Wilson, David J; Owen, Sara; Corkill, Rufus A

    2013-07-01

    Coblation to create a cavity in the affected vertebral body was performed for complex fractures and/or when there was a posterior wall defect. This permitted a low-pressure injection and potentially reduces the risk of extravasation of cement into the spinal canal. Prospective audit for outcome measures and complications allowed retrospective review of cases treated by coblation. A commercial wand inserted via a wide-bore vertebroplasty needle created a cavity before inserting cement. A visual analogue scale assessed pain and Roland Morris scoring assessed mobility. Thirty-two coblation procedures were performed. Primary diagnoses were myeloma, metastases, osteoporosis and trauma. Outcome measures were recorded with a 56 % success rate, 6 % no change and 32 % with mixed but mainly positive results; 6 % died before follow-up. No complications were observed; in particular no patient suffered neurological damage and none have developed subsequent fractures at the treated levels. This technique makes possible cementation of patients who would otherwise be unsuitable for vertebroplasty. The modest pain and disability improvement is partly due to our stringent criteria as well as fracture complexity. Further work will assess the efficacy of the method compared with conservative measures. • Treatment of vertebral compression fractures with possible posterior wall defects is controversial. • Coblation before vertebroplasty allows a low-pressure injection into fractured vertebrae. • This technique reduces risk of extravasation of cement. • No serious complication of our coblation procedures was observed.

  9. Fracture identification based on remote detection acoustic reflection logging

    NASA Astrophysics Data System (ADS)

    Zhang, Gong; Li, Ning; Guo, Hong-Wei; Wu, Hong-Liang; Luo, Chao

    2015-12-01

    Fracture identification is important for the evaluation of carbonate reservoirs. However, conventional logging equipment has small depth of investigation and cannot detect rock fractures more than three meters away from the borehole. Remote acoustic logging uses phase-controlled array-transmitting and long sound probes that increase the depth of investigation. The interpretation of logging data with respect to fractures is typically guided by practical experience rather than theory and is often ambiguous. We use remote acoustic reflection logging data and high-order finite-difference approximations in the forward modeling and prestack reverse-time migration to image fractures. First, we perform forward modeling of the fracture responses as a function of the fracture-borehole wall distance, aperture, and dip angle. Second, we extract the energy intensity within the imaging area to determine whether the fracture can be identified as the formation velocity is varied. Finally, we evaluate the effect of the fracture-borehole distance, fracture aperture, and dip angle on fracture identification.

  10. Primary drainage in geological fractures: Effects of aperture variability and wettability

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Méheust, Y.; Neuweiler, I.

    2017-12-01

    Understanding and controlling fluid-fluid displacement in porous and fractured media is a key asset for many practical applications, such as the geological storage of CO2, hydrocarbon recovery, groundwater remediation, etc. We numerically investigate fluid-fluid displacement in rough-walled fractures with a focus on the combined effect of wettability, the viscous contrast between the two fluids, and fracture surface topography on drainage patterns and interface growth. A model has been developed to simulate the dynamic displacement of one fluid by another immiscible one in a rough geological fracture; the model takes both capillary and viscous forces into account. Capillary pressures at the fluid-fluid interface are calculated based on the Young-Laplace equation using the two principal curvatures (aperture-induced curvature and in-plane curvature) [1], while viscous forces are calculated by continuously solving the fluid pressure field in the fracture. The aperture field of a fracture is represented by a spatially correlated random field, with a power spectral density of the fracture wall topographies scaling as a power law, and a cutoff wave-length above which the Fourier modes of the two walls are identical [2]. We consider flow scenarios with both rectangular and radial configurations. Results show that the model is able to produce displacement patterns of compact displacement, capillary fingering, and viscous fingering, as well as the transitions between them. Both reducing the aperture variability and increasing the contact angle (from drainage to weak imbibition) can stabilize the displacement due to the influence of the in-plane curvature, an effect analogous to that of the cooperative pore filling in porous media. These results suggest that for geometries typical of geological fractures we can extend the phase diagram in the parameter space of capillary number and mobility ratio by another dimension to take into account the combined effect of wettability

  11. Contaminant behavior in fractured sedimentary rocks: Seeing the fractures that matter

    NASA Astrophysics Data System (ADS)

    Parker, B. L.

    2017-12-01

    High resolution spatial sampling of continuous cores from sites contaminated with chlorinated solvents over many decades was used as a strategy to quantify mass stored in low permeability blocks of rock between hydraulically active fractures. Given that core and geophysical logging methods cannot distinguish between hydraulically active fractures and those that do not transmit water, these samples were informed by careful logging of visible fracture features in the core with sample spacing determined by modelled diffusion transport distances given rock matrix properties and expected ages of contamination. These high resolution contaminant concentration profiles from long term contaminated sites in sedimentary rock showed evidence of many more hydraulically active fractures than indicated by the most sophisticated open-hole logging methods. Fracture density is an important attribute affecting fracture connectivity and influencing contaminant plume evolution in fractured porous sedimentary rock. These contaminant profile findings were motivation to find new borehole methods to directly measure hydraulically active fracture occurrence and flux to corroborate the long term "DNAPL tracer experiment" results. Improved sensitivity is obtained when boreholes are sealed using flexible fabric liners (FLUTeTM technology) and various sensor options are deployed in the static water columns used to inflate these liners or in contact with the borehole wall behind the liners. Several methods rely on high resolution temperature measurements of ambient or induced temperature variability such as temperature vector probes (TVP), fiber optic cables for distributed temperature sensing (DTS), both using active heat; packer testing, point dilution testing and groundwater flux measurements between multiple straddle packers to account for leakage. In all cases, numerous hydraulically active fractures are identified over 100 to 300 meters depth, with a large range in transmissivities and

  12. "Blind spots" in forensic autopsy: improved detection of retrobulbar hemorrhage and orbital lesions by postmortem computed tomography (PMCT).

    PubMed

    Flach, P M; Egli, T C; Bolliger, S A; Berger, N; Ampanozi, G; Thali, M J; Schweitzer, W

    2014-09-01

    The purpose of this study was to correlate the occurrence of retrobulbar hemorrhage (RBH) with mechanism of injury, external signs and autopsy findings to postmortem computed tomography (PMCT). Six-teen subjects presented with RBH and underwent PMCT, external inspection and conventional autopsy. External inspection was evaluated for findings of the bulbs, black eye, raccoon eyes and Battle's sign. Fractures of the viscerocranium, orbital lesions and RBH were evaluated by PMCT. Autopsy and PMCT was evaluated for orbital roof and basilar skull fracture. The leading manner of death was accident with central regulatory failure in cases of RBH (31.25%). Imaging showed a high sensitivity in detection of orbital roof and basilar skull fractures (100%), but was less specific compared to autopsy. Volume of RBH (0.1-2.4ml) correlated positively to the presence of Battle's sign (p<0.06) and the postmortem interval. Ecchymosis on external inspection correlated with RBH. There was a statistical significant correlation between bulbar lesion and RBH. Orbital roof fracture count weakly correlated with the total PMCT derived RBH volume. Maxillary hemosinus correlated to maxillary fractures, but not to RBH. RBH are a specific finding in forensically relevant head trauma. PMCT is an excellent tool in detecting and quantifying morphological trauma findings particularly in the viscerocranium, one of the most relevant "blind spots" of classic autopsy. PMCT was superior in detecting osseous lesions, scrutinizing autopsy as the gold standard. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Crater Wall in Van de Graaff

    NASA Image and Video Library

    2010-02-11

    This image taken NASA Lunar Reconnaissance Orbiter shows the wall of crater Van de Graaff C, where brighter material is exposed by more active processes associated with steeper slopes, recent small craters, and even individual rolling boulders.

  14. The role of local stress perturbation on the simultaneous opening of orthogonal fractures

    NASA Astrophysics Data System (ADS)

    Boersma, Quinten; Hardebol, Nico; Barnhoorn, Auke; Bertotti, Giovanni; Drury, Martyn

    2016-04-01

    Orthogonal fracture networks (ladder-like networks) are arrangements that are commonly observed in outcrop studies. They form a particularly dense and well connected network which can play an important role in the effective permeability of tight hydrocarbon or geothermal reservoirs. One issue is the extent to which both the long systematic and smaller cross fractures can be simultaneously critically stressed under a given stress condition. Fractures in an orthogonal network form by opening mode-I displacements in which the main component is separation of the two fracture walls. This opening is driven by effective tensile stresses as the smallest principle stress acting perpendicular to the fracture wall, which accords with linear elastic fracture mechanics. What has been well recognized in previous field and modelling studies is how both the systematic fractures and perpendicular cross fractures require the minimum principle stress to act perpendicular to the fracture wall. Thus, these networks either require a rotation of the regional stress field or local perturbations in stress field. Using a mechanical finite element modelling software, a geological case of layer perpendicular systematic mode I opening fractures is generated. New in our study is that we not only address tensile stresses at the boundary, but also address models using pore fluid pressure. The local stress in between systematic fractures is then assessed in order to derive the probability and orientation of micro crack propagation using the theory of sub critical crack growth and Griffith's theory. Under effective tensile conditions, the results indicate that in between critically spaced systematic fractures, local effective tensile stresses flip. Therefore the orientation of the least principle stress will rotate 90°, hence an orthogonal fracture is more likely to form. Our new findings for models with pore fluid pressures instead of boundary tension show that the magnitude of effective tension

  15. Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics.

    PubMed

    Imai, T; Sukegawa, S; Kanno, T; Fujita, G; Yamamoto, N; Furuki, Y; Michizawa, M

    2014-01-01

    The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus. Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture.

  16. Thermal analysis of fractures at Cerberus Fossae, Mars: Detection of air convection in the porous debris apron

    NASA Astrophysics Data System (ADS)

    Antoine, R.; Lopez, T.; Baratoux, D.; Rabinowicz, M.; Kurita, K.

    2011-08-01

    This study investigates the cause of high nighttime temperatures within Cerberus Fossae, a system of fractures affecting the Central Elysium Planitia. The inner parts (walls and floor) of the fractures are up to 40 K warmer than the surrounding plains. However, several temperature profiles exhibit a local temperature minima occurring in the central part of the fractures. We examined first the influence of cooling efficiency at night in the case of a strong reduction of the sky proportion induced by the fracture's geometry. However, the lack of correlation between temperature and sky proportion, calculated from extracted Mars Orbiter Laser Altimeter (MOLA) profiles argues against this hypothesis. Albedo variations were considered but appear to be limited within the fractures, and are generally not correlated with the temperatures. Variations of the thermal properties of bedrocks exposures, debris aprons and sand dunes inferred from high-resolution images do not either correlate with temperature variations within the fractures. As none of these factors taken alone, or combined, can satisfactorily explain the temperature variations within and near the fracture, we suggest that geothermal heat transported by air convection within the porous debris aprons may contribute to explain high temperatures at night and the local minima on the fracture floor. The conditions for the occurrence of the suggested phenomenon and the consequences on the surface temperature are numerically explored. A conservative geothermal gradient of 20 mW/m 2 was used in the simulations, this value being consistent with either inferred lithosphere elastic thicknesses below the shield volcanoes of the Tharsis dome or values predicted from numerical simulations of the thermal evolution of Mars. The model results indicate that temperature differences of 10-20 K between the central and upper parts of the fracture are explained in the case of high Darcy velocities which require high permeability values

  17. Primary Orbital Chondromyxoid Fibroma: A Rare Case.

    PubMed

    Mullen, Martin G; Somogyi, Marie; Maxwell, Sean P; Prabhu, Vikram; Yoo, David K

    A 56-year-old male with history of chronic sinusitis was found to have a 3 cm left orbital lesion on CT. Subsequent MRI demonstrated a multilobulated enhancing soft tissue lesion at the superotemporal region of the left orbit. Initial biopsy was reported as a low-grade sarcoma. On further evaluation, a consensus was made that the lesion was likely a benign mixed mesenchymal type tumor but should nonetheless be surgically removed. Left lateral orbitotomy was performed which revealed a tumor originating in the lateral orbital bone with segments eroding through the wall of the orbit. Intraoperative frozen sections revealed myoepitheliod tissue with locally aggressive features and the tumor was completely removed. The final histopathologic analysis of the tissue was consistent with a chondromyxoid fibroma. Chondomyxoid fibroma is a rare entity in the orbital bones and is more commonly seen in long bones.

  18. Modeling Dynamic Fracture of Cryogenic Pellets

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

    Parks, Paul

    This work is part of an investigation with the long-range objective of predicting the size distribution function and velocity dispersion of shattered pellet fragments after a large cryogenic pellet impacts a solid surface at high velocity. The study is vitally important for the shattered pellet injection (SPI) technique, one of the leading technologies being implemented at ORNL for the mitigation of disruption damage on current tokamaks and ITER. The report contains three parts that are somewhat interwoven. In Part I we formulated a self-similar model for the expansion dynamics and velocity dispersion of the debris cloud following pellet impact againstmore » a thick (rigid) target plate. Also presented in Part I is an analytical fracture model that predicts the nominal or mean size of the fragments in the debris cloud and agrees well with known SPI data. The aim of Part II is to gain an understanding of the pellet fracturing process when a pellet is shattered inside a miter tube with a sharp bend. Because miter tubes have a thin stainless steel (SS) wall a permanent deformation (dishing) of the wall is produced at the site of the impact. A review of the literature indicates that most projectile impact on thin plates are those for which the target is deformed and the projectile is perfectly rigid. Such impacts result in “projectile embedding” where the projectile speed is reduced to zero during the interaction so that all the kinetic energy (KE) of the projectile goes into the energy stored in plastic deformation. Much of the literature deals with perforation of the target. The problem here is quite different; the softer pellet easily undergoes complete material failure causing only a small transfer of KE to stored energy of wall deformation. For the real miter tube, we derived a strain energy function for the wall deflection using a non-linear (plastic) stress-strain relation for 304 SS. Using a dishing profile identical to the linear Kirchkoff-Love profile

  19. Orbital Reconstruction: Patient-Specific Orbital Floor Reconstruction Using a Mirroring Technique and a Customized Titanium Mesh.

    PubMed

    Tarsitano, Achille; Badiali, Giovanni; Pizzigallo, Angelo; Marchetti, Claudio

    2016-10-01

    Enophthalmos is a severe complication of primary reconstruction of orbital floor fractures. The goal of secondary reconstruction procedures is to restore symmetrical globe positions to recover function and aesthetics. The authors propose a new method of orbital floor reconstruction using a mirroring technique and a customized titanium mesh, printed using a direct metal laser-sintering method. This reconstructive protocol involves 4 steps: mirroring of the healthy orbit at the affected site, virtual design of a patient-specific orbital floor mesh, CAM procedures for direct laser-sintering of the customized titanium mesh, and surgical insertion of the device. Using a computed tomography data set, the normal, uninjured side of the craniofacial skeleton was reflected onto the contralateral injured side, and a reconstructive orbital floor mesh was designed virtually on the mirrored orbital bone surface. The solid-to-layer files of the mesh were then manufactured using direct metal laser sintering, which resolves the shaping and bending biases inherent in the indirect method. An intraoperative navigation system ensured accuracy of the entire procedure. Clinical outcomes were assessed using 3dMD photogrammetry and computed tomography data in 7 treated patients. The technique described here appears to be a viable method to correct complex orbital floor defects needing delayed reconstruction. This study represents the first step in the development of a wider experimental protocol for orbital floor reconstruction using computer-assisted design-computer-assisted manufacturing technology.

  20. [Two-wall decompression without resection of the medial wall. Effect on squint angle].

    PubMed

    Bertelmann, E; Rüther, K

    2011-11-01

    Postoperative new onset diplopia can be a disadvantage for surgical orbital decompression in patients with exophthalmos in thyroid eye disease. The various modifications of decompression (number and combination of walls) differ in their influence on the postoperative squint angle. We report on postoperative diplopia in a modified 2 wall decompression strategy (lateral wall and floor). This study was a retrospective analysis of 36 consecutive 2-wall decompressions performed between 2006-2010 in 24 patients with 6 months of stable exophthalmos in thyroid eye disease after medical therapy and radiotherapy. The preoperative and postoperative squint angle in prism cover test (PCT), motility, induction of diplopia, reduction of exophthalmos, visual acuity and complications were evaluated. In all 36 decompressions the postoperative squint angle was equal to or less than before surgery. In 8 eyes additional squint surgery was performed. The mean reduction in exopthalmos was 4.3 mm. An adverse effect of decompression on the postoperative squint angle was not evident in this study. New induction of diplopia was not observed at all. One possible explanation is the preservation of the medial wall.

  1. BUMPERII - DESIGN ANALYSIS CODE FOR OPTIMIZING SPACECRAFT SHIELDING AND WALL CONFIGURATION FOR ORBITAL DEBRIS AND METEOROID IMPACTS

    NASA Technical Reports Server (NTRS)

    Hill, S. A.

    1994-01-01

    BUMPERII is a modular program package employing a numerical solution technique to calculate a spacecraft's probability of no penetration (PNP) from man-made orbital debris or meteoroid impacts. The solution equation used to calculate the PNP is based on the Poisson distribution model for similar analysis of smaller craft, but reflects the more rigorous mathematical modeling of spacecraft geometry, orientation, and impact characteristics necessary for treatment of larger structures such as space station components. The technique considers the spacecraft surface in terms of a series of flat plate elements. It divides the threat environment into a number of finite cases, then evaluates each element of each threat. The code allows for impact shielding (shadowing) of one element by another in various configurations over the spacecraft exterior, and also allows for the effects of changing spacecraft flight orientation and attitude. Four main modules comprise the overall BUMPERII package: GEOMETRY, RESPONSE, SHIELD, and CONTOUR. The GEOMETRY module accepts user-generated finite element model (FEM) representations of the spacecraft geometry and creates geometry databases for both meteoroid and debris analysis. The GEOMETRY module expects input to be in either SUPERTAB Universal File Format or PATRAN Neutral File Format. The RESPONSE module creates wall penetration response databases, one for meteoroid analysis and one for debris analysis, for up to 100 unique wall configurations. This module also creates a file containing critical diameter as a function of impact velocity and impact angle for each wall configuration. The SHIELD module calculates the PNP for the modeled structure given exposure time, operating altitude, element ID ranges, and the data from the RESPONSE and GEOMETRY databases. The results appear in a summary file. SHIELD will also determine the effective area of the components and the overall model, and it can produce a data file containing the probability

  2. Pediatric facial fractures: evolving patterns of treatment.

    PubMed

    Posnick, J C; Wells, M; Pron, G E

    1993-08-01

    This study reviews the treatment of facial trauma between October 1986 and December 1990 at a major pediatric referral center. The mechanism of injury, location and pattern of facial fractures, pattern of facial injury, soft tissue injuries, and any associated injuries to other organ systems were recorded, and fracture management and perioperative complications reviewed. The study population consisted of 137 patients who sustained 318 facial fractures. Eighty-one patients (171 fractures) were seen in the acute stage, and 56 patients (147 fractures) were seen for reconstruction of a secondary deformity. Injuries in boys were more prevalent than in girls (63% versus 37%), and the 6- to 12-year cohort made up the largest group (42%). Most fractures resulted from traffic-related accidents (50%), falls (23%), or sports-related injuries (15%). Mandibular (34%) and orbital fractures (23%) predominated; fewer midfacial fractures (7%) were sustained than would be expected in a similar adult population. Three quarters of the patients with acute fractures required operative intervention. Closed reduction techniques with maxillomandibular fixation were frequently chosen for mandibular condyle fractures and open reduction techniques (35%) for other regions of the facial skeleton. When open reduction was indicated, plate-and-screw fixation was the preferred method of stabilization (65%). The long-term effects of the injuries and the treatment given on facial growth remain undetermined. Perioperative complication rates directly related to the surgery were low.

  3. Transport of Particle Swarms Through Variable Aperture Fractures

    NASA Astrophysics Data System (ADS)

    Boomsma, E.; Pyrak-Nolte, L. J.

    2012-12-01

    Particle transport through fractured rock is a key concern with the increased use of micro- and nano-size particles in consumer products as well as from other activities in the sub- and near surface (e.g. mining, industrial waste, hydraulic fracturing, etc.). While particle transport is often studied as the transport of emulsions or dispersions, particles may also enter the subsurface from leaks or seepage that lead to particle swarms. Swarms are drop-like collections of millions of colloidal-sized particles that exhibit a number of unique characteristics when compared to dispersions and emulsions. Any contaminant or engineered particle that forms a swarm can be transported farther, faster, and more cohesively in fractures than would be expected from a traditional dispersion model. In this study, the effects of several variable aperture fractures on colloidal swarm cohesiveness and evolution were studied as a swarm fell under gravity and interacted with the fracture walls. Transparent acrylic was used to fabricate synthetic fracture samples with (1) a uniform aperture, (2) a converging region followed by a uniform region (funnel shaped), (3) a uniform region followed by a diverging region (inverted funnel), and (4) a cast of a an induced fracture from a carbonate rock. All of the samples consisted of two blocks that measured 100 x 100 x 50 mm. The minimum separation between these blocks determined the nominal aperture (0.5 mm to 20 mm). During experiments a fracture was fully submerged in water and swarms were released into it. The swarms consisted of a dilute suspension of 3 micron polystyrene fluorescent beads (1% by mass) with an initial volume of 5μL. The swarms were illuminated with a green (525 nm) LED array and imaged optically with a CCD camera. The variation in fracture aperture controlled swarm behavior. Diverging apertures caused a sudden loss of confinement that resulted in a rapid change in the swarm's shape as well as a sharp increase in its velocity

  4. Operative Fixation of Rib Fractures Indications, Techniques, and Outcomes.

    PubMed

    Galos, David; Taylor, Benjamin; McLaurin, Toni

    2017-01-01

    Rib fractures are extremely common injuries and vary in there severity from single nondisplaced fractures to multiple segmental fractures resulting in flail chest and respiratory compromise. Historically, rib fractures have been treated conservatively with pain control and respiratory therapy. However this method may not be the best treatment modality in all situations. Operative fixation of select rib fractures has been increasing in popularity especially in patients with flail chest and respiratory compromise. Newer techniques use muscle sparing approaches and precontoured locking plate technology to obtain stable fixation and allow improved respiration. Current reports shows that rib fracture fixation offers the benefits of improved respiratory mechanics and improved pain control in the severe chest wall injury with resultant improvement in patient outcomes by decreasing time on the ventilator, time in the intensive care unit, and overall hospital length of stay.

  5. Hydrologic effects of stress-relief fracturing in an Appalachian Valley

    USGS Publications Warehouse

    Wyrick, Granville G.; Borchers, James W.

    1981-01-01

    A hydrologic study at Twin Falls State Park, Wyoming County, West Virginia, was made to determine how fracture systems affect the occurrence and movement of ground water in a typical valley of the Appalachian Plateaus Physiographic Province. Twin Falls was selected because it is generally unaffected by factors that would complicate an analysis of the data. The study area was the Black Fork Valley at Twin Falls. The valley is about 3 miles long and 400 to 600 feet wide and is cut into massive sandstone units interbedded with thin coal and shale beds. The study was made to determine how aquifer characteristics were related to fracture systems in this valley, so that the relation could be applied to studies of other valleys. Two sites were selected for test drilling, pumping tests, and geophysical studies. One site is in the upper part of the valley, and the second is near the lower central part. At both sites, ground water occurs mainly in horizontal bedding-plane fractures under the valley floor and in nearly vertical and horizontal slump fractures along the valley wall. The aquifer is under confined conditions under the valley floor and unconfined conditions along the valley wall. The fractures pinch out under the valley walls, which form impermeable barriers. Tests of wells near the valley center indicated a change in storage coefficient as the cone of depression caused by pumping reached the confined-unconfined boundaries; the tests also indicated barrier-image effects when the cone reached the impermeable boundaries. Drawdown from pumping near the center of the valley affected water levels at both sites, indicating a hydraulic connection from the upper to the lower end of the valley. Stream gain-and-loss studies show that ground water discharges to the stream from horizontal fractures beneath Black Fork Falls, near the mouth of Black Fork. The fracture systems that constitute most of the transmissive part of the aquifer at Twin Falls are like those described as

  6. Primary Intraosseous Hemangioma of the Orbital Roof: A Pitfall of Surgery.

    PubMed

    Wu, Chih-Ying; Huang, Hsiang-Ming; Chen, Der-Cherng; Cho, Der-Yang; Wei, Sung-Tai

    2016-09-01

    A primary intraosseous hemangioma (IOH) of the orbital bone is extremely rare. The preferred method of treatment for IOH is total surgical excision with reconstruction. Herein, the authors describe a patient with an orbital roof IOH and the unexpected complications of ptosis and deteriorated exophthalmos. These findings showed that the total surgical excision and subsequent reconstruction provided adequate decompression and prevented further ocular complications from the orbital wall defect.

  7. Mandibular fracture patterns consistent with posterior maxillary fractures involving the posterior maxillary sinus, pterygoid plate or both: CT characteristics

    PubMed Central

    Sukegawa, S; Kanno, T; Fujita, G; Yamamoto, N; Furuki, Y; Michizawa, M

    2014-01-01

    Objectives: The aim of this study was to determine the incidence of posterior maxillary fractures involving the posterior maxillary sinus wall, pterygoid plate or both, unrelated to major midface fractures in patients with mandibular fractures, and to characterize associated fractures. Methods: A CT study was performed in patients with mandibular fractures to identify posterior maxillary fractures. Patients aged under 16 years, those with mandibular fractures involving only dentoalveolar components and those with concurrent major midfacial fractures were excluded. Results: 13 (6.7%) of 194 patients with mandibular fractures also had posterior maxillary fractures (case group). The injury pattern correlated with the external force directed to the lateral side of the mandible (p < 0.001), alcohol consumption (p = 0.049), the presence of multifocal fractures (p = 0.002) and the fracture regions in the symphysis/parasymphysis (p = 0.001) and the angle/ramus (p = 0.001). No significant difference between the case and non-case groups was seen for age, sex or cause of trauma. Non-displaced fractures in the ipsilateral posterior mandible occurred with significant frequency (p = 0.001) when the posterior maxillary fractures involved only the sinus. Conclusions: Mandibular fractures accompanied by posterior maxillary fractures are not rare. The finding of a unilateral posterior maxillary fracture on CT may aid the efficient radiological examination of the mandible based on possible patterns of associated fractures, as follows: in the ipsilateral posterior region as a direct fracture when the impact is a medially directed force, and in the symphysis/parasymphysis or contralateral condylar neck as an indirect fracture. PMID:24336313

  8. The Influence of Fracturing Fluids on Fracturing Processes: A Comparison Between Water, Oil and SC-CO2

    NASA Astrophysics Data System (ADS)

    Wang, Jiehao; Elsworth, Derek; Wu, Yu; Liu, Jishan; Zhu, Wancheng; Liu, Yu

    2018-01-01

    Conventional water-based fracturing treatments may not work well for many shale gas reservoirs. This is due to the fact that shale gas formations are much more sensitive to water because of the significant capillary effects and the potentially high contents of swelling clay, each of which may result in the impairment of productivity. As an alternative to water-based fluids, gaseous stimulants not only avoid this potential impairment in productivity, but also conserve water as a resource and may sequester greenhouse gases underground. However, experimental observations have shown that different fracturing fluids yield variations in the induced fracture. During the hydraulic fracturing process, fracturing fluids will penetrate into the borehole wall, and the evolution of the fracture(s) then results from the coupled phenomena of fluid flow, solid deformation and damage. To represent this, coupled models of rock damage mechanics and fluid flow for both slightly compressible fluids and CO2 are presented. We investigate the fracturing processes driven by pressurization of three kinds of fluids: water, viscous oil and supercritical CO2. Simulation results indicate that SC-CO2-based fracturing indeed has a lower breakdown pressure, as observed in experiments, and may develop fractures with greater complexity than those developed with water-based and oil-based fracturing. We explore the relation between the breakdown pressure to both the dynamic viscosity and the interfacial tension of the fracturing fluids. Modeling demonstrates an increase in the breakdown pressure with an increase both in the dynamic viscosity and in the interfacial tension, consistent with experimental observations.

  9. Orbital invasion routes of non-melanoma skin cancers and survival outcomes.

    PubMed

    Dundar, Yusuf; Cannon, Richard; Wiggins, Richard; Monroe, Marcus M; Buchmann, Luke O; Hunt, Jason P

    2018-02-21

    Overall non-melanoma head and neck skin cancer has a good prognosis; however, rarely patients have an aggressive variant which results in orbital invasion via perineural spread or direct extension. Despite these consequences, there are limited published studies defining this clinical entity. The main objectives of the current study are to describe orbital invasion patterns of non-melanoma head and neck skin cancers and their impact on survival. Retrospective case series from a tertiary-care, academic institution performed between 2004 and 2014. Demographic and tumour characteristics are reported as well as patterns of orbital invasion, types of treatments received, and survival outcomes. There were 17 consecutive patients with non-melanoma skin cancer and orbital invasion who met inclusion criteria. Average age at orbital invasion diagnosis was 70.8 years old. 76% were male. Mean follow-up time was 28.5 months. Of these patients, 71% had squamous cell carcinoma and 29% had basal cell carcinoma. Brow (41%) was the most common primary sub-site followed by cheek (23%) and temple (12%). 76% of patients had a history of prior treatment. The lateral orbital wall (41%) was the most common site of invasion, followed by the medial orbital wall (29%) and antero-superior invasion (23%). Age, histology, and location of orbital invasion were associated with disease-specific and overall survival. Orbital invasion for non-melanoma head and neck skin cancers creates a treatment dilemma and the patterns of invasion are described. In addition, the location of orbital invasion is associated with survival outcomes.

  10. Analysis of a Floodplain I-Wall Embedded in Horizontally Stratified Soil Layers During Flood Events Using Corps I-Wall Software Version 1.0

    DTIC Science & Technology

    2016-07-01

    and gap propagation engineering methodology implemented within the software (CI-Wall) makes use of a hydraulic fracturing criterion, as discussed in...moist unit weight). Soil unit weights: Because of the presence of the upper moist (i.e, non - saturated) region R01 clay layer that is immediately...from two series of complete soil-structure interaction (SSI) non - linear finite element studies for I-Walls at New Orleans and other locations

  11. Ultrasonography in the diagnosis of nasal bone fractures: a comparison with conventional radiography and computed tomography.

    PubMed

    Lee, In Sook; Lee, Jung-Hoon; Woo, Chang-Ki; Kim, Hak Jin; Sol, Yu Li; Song, Jong Woon; Cho, Kyu-Sup

    2016-02-01

    The purpose of this study was to evaluate and compare the diagnostic efficacy of ultrasonography (US) with radiography and multi-detector computed tomography (CT) for the detection of nasal bone fractures. Forty-one patients with a nasal bone fracture who underwent prospective US examinations were included. Plain radiographs and CT images were obtained on the day of trauma. For US examinations, radiologist used a linear array transducer (L17-5 MHz) in 24 patients and hockey-stick probe (L15-7 MHz) in 17. The bony component of the nose was divided into three parts (right and left lateral nasal walls, and midline of nasal bone). Fracture detection by three modalities was subjected to analysis. Furthermore, findings made by each modality were compared with intraoperative findings. Nasal bone fractures were located in the right lateral wall (n = 28), midline of nasal bone (n = 31), or left lateral wall (n = 31). For right and left lateral nasal walls, CT had greater sensitivity and specificity than US or radiography, and better agreed with intraoperative findings. However, for midline fractures of nasal bone, US had higher specificity, positive predictive value, and negative predictive value than CT. Although two US evaluations showed good agreements at all three sites, US findings obtained by the hockey-stick probe showed closer agreement with intraoperative findings for both lateral nasal wall and midline of nasal bone. Although CT showed higher sensitivity and specificity than US or radiography, US found to be helpful for evaluating the midline of nasal bone. Furthermore, for US examinations of the nasal bone, a smaller probe and higher frequency may be required.

  12. Fast switching and signature of efficient domain wall motion driven by spin-orbit torques in a perpendicular anisotropy magnetic insulator/Pt bilayer

    NASA Astrophysics Data System (ADS)

    Avci, Can Onur; Rosenberg, Ethan; Baumgartner, Manuel; Beran, Lukáš; Quindeau, Andy; Gambardella, Pietro; Ross, Caroline A.; Beach, Geoffrey S. D.

    2017-08-01

    We report fast and efficient current-induced switching of a perpendicular anisotropy magnetic insulator thulium iron garnet by using spin-orbit torques (SOT) from the Pt overlayer. We first show that, with quasi-DC (10 ms) current pulses, SOT-induced switching can be achieved with an external field as low as 2 Oe, making TmIG an outstanding candidate to realize efficient switching in heterostructures that produce moderate stray fields without requiring an external field. We then demonstrate deterministic switching with fast current pulses (≤20 ns) with an amplitude of ˜1012 A/m2, similar to all-metallic structures. We reveal that, in the presence of an initially nucleated domain, the critical switching current is reduced by up to a factor of five with respect to the fully saturated initial state, implying efficient current-driven domain wall motion in this system. Based on measurements with 2 ns-long pulses, we estimate the domain wall velocity of the order of ˜400 m/s per j = 1012 A/m2.

  13. Clinical prognostic factors and grading system for rib fracture following stereotactic body radiation therapy (SBRT) in patients with peripheral lung tumors.

    PubMed

    Kim, Su Ssan; Song, Si Yeol; Kwak, Jungwon; Ahn, Seung Do; Kim, Jong Hoon; Lee, Jung Shin; Kim, Woo Sung; Kim, Sang-We; Choi, Eun Kyung

    2013-02-01

    Several studies reported rib fractures following stereotactic body radiation therapy (SBRT) for peripheral lung tumors. We tried to investigate risk factors and grading system for rib fractures after SBRT. Of 375 primary or metastatic lung tumors (296 patients) which were treated with SBRT at the Asan Medical Center (2006-2009), 126 lesions (118 patients) were adjacent to the chest-wall (<1cm) and followed-up with chest computed tomography (CT) for >6 months; these were investigated in the present retrospective study. Three to four fractional doses of 10-20 Gy were delivered to 85-90% iso-dose volume of the isocenter dose. Rib fracture grade was defined from follow-up CT scans as the appearance of a fracture line (Gr1), dislocation of the fractured rib by more than half the rib diameter (Gr2), or the appearance of adjacent soft tissue edema (Gr3). Chest wall pain was assessed according to the Common Terminology Criteria for Adverse Events (CTCAE) v3.0. Correlations between dose-volume data and the development of rib fracture were then analyzed. The Kaplan-Meier method, log-rank tests, and chi-square tests were used for statistical analysis. The median age of the patients was 69 years (range: 19-90). Over a median follow-up period of 22 months (range: 7-62), 48 cases of rib fracture were confirmed. Median time to rib fracture was 17 months (range: 4-52). The 2-year actuarial risk of rib fracture was 42.4%. Maximal grade was Gr1 (n=28), Gr2 (n=8), or Gr3 (n=15). The incidence of moderate to severe chest wall pain (CTCAE Gr ≥ 2) increased with maximal fracture grade (17.5% for Gr0-1 and 60.9% for Gr2-3; p<0.001). Multivariate analysis identified female gender, lateral location, and the dose to the 8cc of the chest wall as significant prognostic factors. Female gender and lateral tumor location were clinical risk factors for rib fracture in the present study. Efforts to decrease chest wall dose should be made to reduce the risk of the rib fracture, particularly in

  14. 3D characterization of the fracture network in a deformed chalk reservoir analogue: The Lagerdorf case

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

    Koestler, A.G.; Reksten, K.

    1994-12-31

    Quantitative descriptions of the 3D fracture networks in terms of connectivity, fracture types, fracture surface roughness and flow characteristics are necessary for reservoir evaluation, management, and enhanced oil recovery programs of fractured reservoirs. For a period of 2 years, a research project focused on an analogue to fractured chalk reservoirs excellently exposed near Laegerdorf, NW Germany. Upper Cretaceous chalk has been uplifted and deformed by an underlying salt diapir, and is now exploited for the cement industry. In the production wall of a quarry, the fracture network of the deformed chalk was characterized and mapped at different scales. The wallmore » was scraped off as chalk exploitation proceeded, continuously revealing new sections through the faulted and fractured chalk body. A 230 m long part of the 35m high production wall was investigated during its recess of 25m. The large amount of fracture data were analyzed with respect to parameters such as fracture density distribution, orientation- and length distribution, and in terms of the representativity of data sets collected from restricted rock volumes. This 3D description and analysis of a fracture network revealed quantitative generic parameters of importance for modeling chalk reservoirs with less data and lower data quality.« less

  15. Chemical Signatures of and Precursors to Fractures Using Fluid Inclusion Stratigraphy

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

    Lorie M. Dilley

    Enhanced Geothermal Systems (EGS) are designed to recover heat from the subsurface by mechanically creating fractures in subsurface rocks. Open or recently closed fractures would be more susceptible to enhancing the permeability of the system. Identifying dense fracture areas as well as large open fractures from small fracture systems will assist in fracture stimulation site selection. Geothermal systems are constantly generating fractures (Moore, Morrow et al. 1987), and fluids and gases passing through rocks in these systems leave small fluid and gas samples trapped in healed microfractures. These fluid inclusions are faithful records of pore fluid chemistry. Fluid inclusions trappedmore » in minerals as the fractures heal are characteristic of the fluids that formed them, and this signature can be seen in fluid inclusion gas analysis. This report presents the results of the project to determine fracture locations by the chemical signatures from gas analysis of fluid inclusions. With this project we hope to test our assumptions that gas chemistry can distinguish if the fractures are open and bearing production fluids or represent prior active fractures and whether there are chemical signs of open fracture systems in the wall rock above the fracture. Fluid Inclusion Stratigraphy (FIS) is a method developed for the geothermal industry which applies the mass quantification of fluid inclusion gas data from drill cuttings and applying known gas ratios and compositions to determine depth profiles of fluid barriers in a modern geothermal system (Dilley, 2009; Dilley et al., 2005; Norman et al., 2005). Identifying key gas signatures associated with fractures for isolating geothermal fluid production is the latest advancement in the application of FIS to geothermal systems (Dilley and Norman, 2005; Dilley and Norman, 2007). Our hypothesis is that peaks in FIS data are related to location of fractures. Previous work (DOE Grant DE-FG36-06GO16057) has indicated differences

  16. Fractures of the manubrium sterni: treatment options and a possible classification of different types of fractures

    PubMed Central

    Krinner, Sebastian; Oppel, Pascal; Grupp, Sina; Schulz-Drost, Melanie; Hennig, Friedrich F.; Langenbach, Andreas

    2018-01-01

    Background Sternum fractures are mostly located on the sternal corpus, seldom on the manubrium. Fractures of the sternal manubrium are, however, more frequently associated with severe concomitant injuries of thoracic organs, and therefore deserve special attention. In addition, in its function as a capstone in between the anterior chest wall and the shoulder girdle, it is exposed to a multiplicity of forces. Therefore the questions arise what types of fractures are observed in today’s clinical practice, how to classify them and which treatment options are available. This study reports on different types of fractures which involve the manubrium sterni. Methods Between January 2012 and October 2014, data was collected from all severely injured patients (ISS ≥16), which received a CT scan of the thorax in our Level-I-Trauma Center and retrospectively analyzed concerning sternal fractures. Fracture type, collateral injuries, age, and information about the circumstances of the accident were noted. Results Of 890 evaluable patients, 154 (17.3%) had a fracture of the sternum and 23 (2.6%) of the manubrium. Fractures of the manubrium appeared in following types: A-type—transverse fracture (n=11) in 1st intercostal space by direct blunt trauma or flexion of the torso with sagittal instability; B-type—oblique fracture (n=9) by seat belt injury with rotatory instability; C-type—combined, more fragmentary fracture (n=3) by direct blunt trauma with simultaneous flexion of the torso and multi directional instability. Fractures only little dislocation were treated conservatively, and unstable fractures were surgically stabilized (n=10). Conclusions In summary, three main types of fractures could be found. A-type fractures were stabilized with a longitudinal plate osteosynthesis and B-type fractures with transverse positioned plates. To treat complex C-type fractures, plates with a T- or H-form could be a good solution. Level of evidence: Level III retrospective

  17. Fractures in Carbonate-Bearing Rocks at Mars Huygens Basin

    NASA Image and Video Library

    2011-03-08

    This false-color image NASA Mars Reconnaissance Orbiter shows that fractures and possible layers are visible in the light-toned rock exposure containing the carbonates. The location is inside an unnamed crater on the uplifted rim of Huygens crater.

  18. Cemented Fractures in Mountain Inside Gale Crater on Mars

    NASA Image and Video Library

    2011-07-22

    One type of feature of scientific interest on the mountain inside Gale crater is exposure of cemented fractures, evidence that groundwater once reached to at least that height of the mountain. This image is from NASA Mars Reconnaissance Orbiter.

  19. Closeup view of the mid deck aft wall of the ...

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

    Close-up view of the mid deck aft wall of the Orbiter Discovery showing a mission specific configuration of stowage lockers within the modular system designed for maximum flexibility. This photograph was taken at Kennedy Space Center. - Space Transportation System, Orbiter Discovery (OV-103), Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston, Harris County, TX

  20. Rib fractures after percutaneous radiofrequency and microwave ablation of lung tumors: incidence and relevance.

    PubMed

    Alexander, Erica S; Hankins, Carol A; Machan, Jason T; Healey, Terrance T; Dupuy, Damian E

    2013-03-01

    To retrospectively identify the incidence and probable risk factors for rib fractures after percutaneous radiofrequency ablation (RFA) and microwave ablation (MWA) of neoplasms in the lung and to identify complications related to these fractures. Institutional review board approval was obtained for this HIPAA-compliant retrospective study. Study population was 163 patients treated with MWA and/or RFA for 195 lung neoplasms between February 2004 and April 2010. Follow-up computed tomographic images of at least 3 months were retrospectively reviewed by board-certified radiologists to determine the presence of rib fractures. Generalized estimating equations were performed to assess the effect that patient demographics, tumor characteristics, treatment parameters, and ablation zone characteristics had on development of rib fractures. Kaplan-Meier curve was used to estimate patients' probability of rib fracture after ablation as a function of time. Clinical parameters (ie, pain in ribs or chest, organ damage caused by fractured rib) were evaluated for patients with confirmed fracture. Rib fractures in proximity to the ablation zone were found in 13.5% (22 of 163) of patients. Estimated probability of fracture was 9% at 1 year and 22% at 3 years. Women were more likely than were men to develop fracture after ablation (P = .041). Patients with tumors closer to the chest wall were more likely to develop fracture (P = .0009), as were patients with ablation zones that involved visceral pleura (P = .039). No patients with rib fractures that were apparently induced by RFA and MWA had organ injury or damage related to fracture, and 9.1% (2 of 22) of patients reported mild pain. Rib fractures were present in 13.5% of patients after percutaneous RFA and MWA of lung neoplasms. Patients who had ablations performed close to the chest wall should be monitored for rib fractures.

  1. Assessing mechanical deconstruction of softwood cell wall for cellulosic biofuels production

    NASA Astrophysics Data System (ADS)

    Jiang, Jinxue

    Mechanical deconstruction offers a promising strategy to overcome biomass recalcitrance for facilitating enzymatic hydrolysis of pretreated substrates with zero chemicals input and presence of inhibitors. The goal of this dissertation research is to gain a more fundamental understanding on the impact of mechanical pretreatment on generating digestible micronized-wood and how the physicochemical characteristics influence the subsequent enzymatic hydrolysis of micronized wood. The initial moisture content of feedstock was found to be the key factor affecting the development of physical features and enzymatic hydrolysis of micronized wood. Lower moisture content resulted in much rounder particles with lower crystallinity, while higher moisture content resulted in the milled particles with larger aspect ratio and crystallinity. The enzymatic hydrolysis of micronized wood was improved as collectively increasing surface area (i.e., reducing particle size and aspect ratio) and decreasing crystallinity during mechanical milling pretreatment. Energy efficiency analysis demonstrated that low-moisture content feedstock with multi-step milling process would contribute to cost-effectiveness of mechanical pretreatment for achieving more than 70% of total sugars conversion. In the early stage of mechanical pretreatment, the types of cell fractures were distinguished by the initial moisture contents of wood, leading to interwall fracture at the middle lamella region for low moisture content samples and intrawall fracture at the inner cell wall for high moisture content samples. The changes in cell wall fractures also resulted in difference in the distribution of surface chemical composition and energy required for milling process. In an effort to exploit the underlying mechanism associated with the reduced recalcitrance in micronized wood, we reported the increased enzymatic sugar yield and correspondingly structural and accessible properties of micronized feedstock. Electronic

  2. Considerations for ultrasonic testing application for on-orbit NDE

    NASA Astrophysics Data System (ADS)

    Koshti, Ajay M.

    2015-04-01

    The paper addresses some on-orbit nondestructive evaluation (NDE) needs of NASA for International Space Station (ISS). The presentation gives NDE requirements for inspecting suspect damage due to micro-meteoroids and orbital debris (MMOD) impact on the pressure wall of the ISS. This inspection is meant to be conducted from inside of the ISS module. The metallic wall of the module has a fixed wall thickness but also has integral orthogrid ribs for reinforcement. Typically, a single MMOD hit causes localized damage in a small area causing loss of material similar to pitting corrosion, but cracks may be present too. The impact may cause bulging of the wall. Results of the ultrasonic and eddy current demonstration scans on test samples are provided. The ultrasonic technique uses shear wave scans to interrogate the localized damage area from the surrounding undamaged area. The scanning protocol results in multiple scans, each with multiple "vee" paths. A superimposition and mosaic of the three-dimensional ultrasonic data from individual scans is desired to create C-scan images of the damage. This is a new data reduction process which is not currently implemented in state-of-art ultrasonic instruments. Results of ultrasonic scans on the simulated MMOD damage test plates are provided. The individual C-scans are superimposed manually creating mosaic of the inspection. The resulting image is compared with visibly detected damage boundaries, X-ray images, and localized ultrasonic and eddy current scans for locating crack tips to assess effectiveness of the ultrasonic scanning. The paper also discusses developments needed in improving ergonomics of the ultrasonic testing for on-orbit applications.

  3. 222Rn transport in a fractured crystalline rock aquifer: Results from numerical simulations

    USGS Publications Warehouse

    Folger, P.F.; Poeter, E.; Wanty, R.B.; Day, W.; Frishman, D.

    1997-01-01

    Dissolved 222Rn concentrations in ground water from a small wellfield underlain by fractured Middle Proterozoic Pikes Peak Granite southwest of Denver, Colorado range from 124 to 840 kBq m-3 (3360-22700 pCi L-1). Numerical simulations of flow and transport between two wells show that differences in equivalent hydraulic aperture of transmissive fractures, assuming a simplified two-fracture system and the parallel-plate model, can account for the different 222Rn concentrations in each well under steady-state conditions. Transient flow and transport simulations show that 222Rn concentrations along the fracture profile are influenced by 222Rn concentrations in the adjoining fracture and depend on boundary conditions, proximity of the pumping well to the fracture intersection, transmissivity of the conductive fractures, and pumping rate. Non-homogeneous distribution (point sources) of 222Rn parent radionuclides, uranium and 226Ra, can strongly perturb the dissolved 222Rn concentrations in a fracture system. Without detailed information on the geometry and hydraulic properties of the connected fracture system, it may be impossible to distinguish the influence of factors controlling 222Rn distribution or to determine location of 222Rn point sources in the field in areas where ground water exhibits moderate 222Rn concentrations. Flow and transport simulations of a hypothetical multifracture system consisting of ten connected fractures, each 10 m in length with fracture apertures ranging from 0.1 to 1.0 mm, show that 222Rn concentrations at the pumping well can vary significantly over time. Assuming parallel-plate flow, transmissivities of the hypothetical system vary over four orders of magnitude because transmissivity varies with the cube of fracture aperture. The extreme hydraulic heterogeneity of the simple hypothetical system leads to widely ranging 222Rn values, even assuming homogeneous distribution of uranium and 226Ra along fracture walls. Consequently, it is

  4. Rib fractures induced by coughing: an unusual cause of acute chest pain.

    PubMed

    De Maeseneer, M; De Mey, J; Debaere, C; Meysman, M; Osteaux, M

    2000-03-01

    We report three patients with stress fractures of the ribs induced by coughing. Standard radiographs of the chest and ribs did not reveal evidence of rib fractures in any of the patients. Bone scintigraphy, performed 1 to 2 weeks after initial onset of symptoms, showed a focal area of increased uptake along the chest wall in all cases. Thin section angulated helical CT directly visualized the subtle rib fractures. Initial diagnosis of a cough-induced fracture of the rib may be difficult because of the associated underlying disorder, and unnecessary examinations are commonly performed. Identification of a cough-induced fracture of the rib using helical CT may be clinically important to avoid unnecessary concern and additional examinations.

  5. Surgical orbital decompression for thyroid eye disease.

    PubMed

    Boboridis, Kostas G; Bunce, Catey

    2011-12-07

    Orbital decompression is an established procedure for the management of exophthalmos and visual rehabilitation from optic neuropathy in cases of thyroid eye disease. Numerous procedures for removal of orbital bony wall, fat or a combination of these for a variety of indications in different stages of the disease have been well reported in the medical literature. However, the relative effectiveness and safety of these procedures in relation to the various indications remains unclear. To review current published evidence for the effectiveness of surgical orbital decompression for disfiguring proptosis in adult thyroid eye disease and summa rise information on possible complications and the quality of life from the studies identified. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 10), MEDLINE (January 1950 to October 2011), EMBASE (January 1980 to October 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (http://clinicaltrials.gov). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 6 October 2011. We searched oculoplastic textbooks, conference proceedings from the European and American Society of Ophthalmic Plastic and Reconstructive Surgery (ESOPRS, ASOPRS), European Ophthalmological Society (SOE), the Association for Research in Vision and Ophthalmology (ARVO) and American Academy of Ophthalmology (AAO) for the years 2000 to 2009 to identify relevant data. We attempted to contact researchers who are active in this field for information about further published or unpublished studies. We included randomised controlled trials (RCTs) with no restriction on date or language comparing two or more surgical methods for orbital decompression with removal of bony wall, orbital fat or a combination of both for disfiguring proptosis or comparison of surgical techniques

  6. Hyperostosis in an orbital defect with craniofacial implants and open-field magnets: a clinical report.

    PubMed

    Sullivan, Maureen; Casey, David M; Alberico, Ronald; Litwin, Alan; Schaaf, Norman G

    2007-04-01

    An orbital facial prosthesis wearer was found to have significant hyperostosis in an exenterated orbit exposed to long-term, open field, rare earth magnets attached to craniofacial implants. Localized exophytic osseous formation was found in multiple areas around the exenterated orbit. The overall thickness of the walls of the exenterated orbit was approximately double that of the unaffected side. Magnetic field effect on bone formation and recommended treatment are discussed.

  7. Fracture Mechanics Analyses of Reinforced Carbon-Carbon Wing-Leading-Edge Panels

    NASA Technical Reports Server (NTRS)

    Raju, Ivatury S.; Phillips, Dawn R.; Knight, Norman F., Jr.; Song, Kyongchan

    2010-01-01

    Fracture mechanics analyses of subsurface defects within the joggle regions of the Space Shuttle wing-leading-edge RCC panels are performed. A 2D plane strain idealized joggle finite element model is developed to study the fracture behavior of the panels for three distinct loading conditions - lift-off and ascent, on-orbit, and entry. For lift-off and ascent, an estimated bounding aerodynamic pressure load is used for the analyses, while for on-orbit and entry, thermo-mechanical analyses are performed using the extreme cold and hot temperatures experienced by the panels. In addition, a best estimate for the material stress-free temperature is used in the thermo-mechanical analyses. In the finite element models, the substrate and coating are modeled separately as two distinct materials. Subsurface defects are introduced at the coating-substrate interface and within the substrate. The objective of the fracture mechanics analyses is to evaluate the defect driving forces, which are characterized by the strain energy release rates, and determine if defects can become unstable for each of the loading conditions.

  8. Effects of aperture variability and wettability on immiscible displacement in fractures

    NASA Astrophysics Data System (ADS)

    Yang, Zhibing; Méheust, Yves; Neuweiler, Insa

    2017-04-01

    Fluid-fluid displacement in porous and fractured media is an important process. Understanding and controlling this process is key to many practical applications, such as hydrocarbon recovery, geological storage of CO2, groundwater remediation, etc. Here, we numerically study fluid-fluid displacement in rough-walled fractures. We focus on the combined effect of wettability and fracture surface topography on displacement patterns and interface growth. We develop a novel numerical model to simulate dynamic fluid invasion under the influence of capillary and viscous forces. The capillary force is calculated using the two principal curvatures (aperture-induced curvature and in-plane curvature) at the fluid-fluid interface, and the viscous force is taken into account by solving the fluid pressure distribution. The aperture field of a fracture is represented by a spatially correlated random field, which is described by a power spectrum for the fracture wall topography and a cutoff wave-length. We numerically produce displacement patterns ranging from stable displacement, capillary fingering, and viscous fingering, as well as the transitions between them. We show that both reducing the aperture variability and increasing the contact angle (from drainage to weak imbibition) stabilize the displacement due to the influence of the in-plane curvature, an effect analogous to that of the cooperative pore filling in porous media. Implications of these results will be discussed.

  9. Electromagnetic image-guided orbital decompression: technique, principles, and preliminary experience with 6 consecutive cases.

    PubMed

    Servat, Juan J; Elia, Maxwell Dominic; Gong, Dan; Manes, R Peter; Black, Evan H; Levin, Flora

    2014-12-01

    To assess the feasibility of routine use of electromagnetic image guidance systems in orbital decompression. Six consecutive patients underwent stereotactic-guided three wall orbital decompression using the novel Fusion ENT Navigation System (Medtronic), a portable and expandable electromagnetic guidance system with multi-instrument tracking capabilities. The system consists of the Medtronic LandmarX System software-enabled computer station, signal generator, field-generating magnet, head-mounted marker coil, and surgical tracking instruments. In preparation for use of the LandmarX/Fusion protocol, all patients underwent preoperative non-contrast CT scan from the superior aspect of the frontal sinuses to the inferior aspect of the maxillary sinuses that includes the nasal tip. The Fusion ENT Navigation System (Medtronic™) was used in 6 patients undergoing maximal 3-wall orbital decompression for Graves' orbitopthy after a minimum of six months of disease inactivity. Preoperative Hertel exophthalmometry measured more than 27 mm in all patients. The navigation system proved to be no more difficult technically than the traditional orbital decompression approach. Electromagnetic image guidance is a stereotactic surgical navigation system that provides additional intraoperative flexibility in orbital surgery. Electromagnetic image-guidance offers the ability to perform more aggressive orbital decompressions with reduced risk.

  10. Fracture Development within the Karaha-Telaga Bodas Geothermal Field, Indonesia

    USGS Publications Warehouse

    Nemcok, M.; Moore, J.N.; Allis, R.; McCulloch, J.

    2002-01-01

    decreasing pore pressures in the expanding vapor zone, the fracture system within the vapor-dominated reservoir progressively collapsed, leaving only residual permeability, with apertures supported by asperities or propping breccia. In places, the fractures have completely collapsed where normal stresses acting on the fracture walls exceeded the compressive strength of the wall rock.

  11. Interplay between the spin transfer and spin orbit torques on domain walls at the 5d/3d-alloy interfaces

    NASA Astrophysics Data System (ADS)

    Kalitsov, Alan; Okatov, Sergey; Zarzhitsky, Pavel; Chshiev, Mairbek; Velev, Julian; Butler, William; Mryasov, Oleg

    2014-03-01

    The manipulations of domain wall (DW) in thin ferromagnetic layers by current and the spin-orbit coupling (SOC) have attracted significant interest. We report two band model calculations of the spin torque (ST) and the spin current (SC) at 5d/3d interfaces with head-to-head, Bloch and Neel DWs. These calculations are based on the non-equilibrium Green Function formalism and the tight binding Hamiltonian including the s-d exchange interactions and the Rashba SOC parameterized on the basis of ab-initio calculations for Fe/W, FeCo/Ta and Co/Pt interfaces. We find that SOC significantly modifies the ST and violates relations between the spin transfer torque and the divergence of the spin current. This work was supported in part by a Semiconductor Research Corporation program, sponsored by MARCO and DARPA.

  12. Mirror-Imaged Rapid Prototype Skull Model and Pre-Molded Synthetic Scaffold to Achieve Optimal Orbital Cavity Reconstruction.

    PubMed

    Park, Sung Woo; Choi, Jong Woo; Koh, Kyung S; Oh, Tae Suk

    2015-08-01

    Reconstruction of traumatic orbital wall defects has evolved to restore the original complex anatomy with the rapidly growing use of computer-aided design and prototyping. This study evaluated a mirror-imaged rapid prototype skull model and a pre-molded synthetic scaffold for traumatic orbital wall reconstruction. A single-center retrospective review was performed of patients who underwent orbital wall reconstruction after trauma from 2012 to 2014. Patients were included by admission through the emergency department after facial trauma or by a tertiary referral for post-traumatic orbital deformity. Three-dimensional (3D) computed tomogram-based mirror-imaged reconstruction images of the orbit and an individually manufactured rapid prototype skull model by a 3D printing technique were obtained for each case. Synthetic scaffolds were anatomically pre-molded using the skull model as guide and inserted at the individual orbital defect. Postoperative complications were assessed and 3D volumetric measurements of the orbital cavity were performed. Paired samples t test was used for statistical analysis. One hundred four patients with immediate orbital defect reconstructions and 23 post-traumatic orbital deformity reconstructions were included in this study. All reconstructions were successful without immediate postoperative complications, although there were 10 cases with mild enophthalmos and 2 cases with persistent diplopia. Reoperations were performed for 2 cases of persistent diplopia and secondary touchup procedures were performed to contour soft tissue in 4 cases. Postoperative volumetric measurement of the orbital cavity showed nonsignificant volume differences between the damaged orbit and the reconstructed orbit (21.35 ± 1.93 vs 20.93 ± 2.07 cm(2); P = .98). This protocol was extended to severe cases in which more than 40% of the orbital frame was lost and combined with extensive soft tissue defects. Traumatic orbital reconstruction can be optimized and

  13. Fracture analysis of radial scientific instrument module registration fittings of the space telescope

    NASA Technical Reports Server (NTRS)

    Springfield, C. W., Jr.

    1985-01-01

    The space telescope contains various scientific instrument (SI) modules which are mounted to the Focal Plane Structure (FPS) in a statically determinate manner. This is accomplished by using three registration fittings per SI module, one resisting three translations, another resisting two and the third resisting only one. Due to thermal insulating requirements these fittings are complex devices composed of numerous pieces. The structural integrity of these fittings is of great importance to the safety of the orbiter transporting the telescope, so in addition to the stress analyses performed during the design of these components, fracture susceptibility also needs to be considered. The pieces of the registration fittings for the Radial SI Module containing the Wide Field Planetary Camera are examined to determine which would endanger the orbiter if they fractured and what is the likelihood of their fracture. The latter is stated in terms of maximum allowable initial flaw sizes in these pieces.

  14. Space station integrated wall design and penetration damage control

    NASA Technical Reports Server (NTRS)

    Coronado, A. R.; Gibbins, M. N.; Wright, M. A.; Stern, P. H.

    1987-01-01

    A methodology was developed to allow a designer to optimize the pressure wall, insulation, and meteoroid/debris shield system of a manned spacecraft for a given spacecraft configuration and threat environment. The threat environment consists of meteoroids and orbital debris, as specified for an arbitrary orbit and expected lifetime. An overall probability of no penetration is calculated, as well as contours of equal threat that take into account spacecraft geometry and orientation. Techniques, tools, and procedures for repairing an impacted and penetrated pressure wall were developed and tested. These techniques are applied from the spacecraft interior and account for the possibility of performing the repair in a vacuum. Hypervelocity impact testing was conducted to: (1) develop and refine appropriate penetration functions, and (2) determine the internal effects of a penetration on personnel and equipment.

  15. Role of the maxillofacial surgeon in the management of severe ocular injuries after maxillofacial fractures

    PubMed Central

    Roccia, Fabio; Boffano, Paolo; Guglielmi, Valeria; Forni, Paolo; Cassarino, Emanuele; Nadalin, Juri; Fea, Antonio; Gerbino, Giovanni

    2011-01-01

    Aim: This study was designed to evaluate the incidence of severe ocular injuries associated to maxillofacial fractures and report their management in the Emergency Department. Patients and Methods: Among the 1779 patients admitted for maxillofacial fractures, those with partial or total loss of vision at the time of emergency consultation were included in the study. Data collected from the patients’ medical records included age, gender, mechanism of injury, location and type of facial fractures, type of ocular injuries and cause of blindness, methods of treatment, and days of hospitalization. Results: Forty patients (2.2%), 32 men and 8 women, ranging from 17 to 85 years of age, presented with severely reduced vision or blindness associated to fractures of the facial middle third with involvement of one or more orbital walls, mainly caused by motor vehicle and work accidents. In 18 patients, severe ocular injuries were determined by direct lesion of the globe, in 14 by direct or indirect traumatic optic neuropathy and in 8 by a retrobulbar hematoma. Direct lesion of the eyeball was treated by prompt repair or enucleation of the globe, though no or little recovery of vision was obtained. Ophthalmologic and/or maxillofacial treatment of the anterior compartment lesions of the eye allowed a partial or total recovery of the vision. A partial or total recovery of the vision was observed in almost all the patients with indirect traumatic optic neuropathy after administration of steroids according to NASCIS II protocol. Likewise, an evident improvement of the vision was obtained by immediate drainage of retrobulbar hematoma. Conclusions: Early diagnosis of the nature of the ophthalmic injury and treatment are important, and involvement of the ophthalmologist is mandatory. PMID:21769204

  16. Computed tomography in the management of orbital infections associated with dental disease.

    PubMed Central

    Flood, T. P.; Braude, L. S.; Jampol, L. M.; Herzog, S.

    1982-01-01

    Two patients developed orbital infection secondary to dental infections. In one patient the infection spread from maxillary premolar and molar teeth to the infratemporal and pterygopalatine fossa and then through the inferior orbital fissure to the subperiosteal space. A subperiosteal abscess in the posterior orbital wall developed, which subsequently spread within the muscle cone. In the second patient infection of an anterior maxillary tooth caused a pansinusitis and unilateral orbital cellulitis. In both patients computed tomographic scanning of the orbit proved valuable in localising the infection and, in one case, planning a surgical approach to the orbit. The infection in both patients responded to treatment, with no permanent visual impairment. Appropriate antibiotics and prompt identification and surgical drainage of orbital abscesses are essential for the preservation of vision in cases of orbital infection. Images PMID:7066283

  17. Reconstruction of Midface and Orbital Wall Defects After Maxillectomy and Orbital Content Preservation With Titanium Mesh and Fascia Lata: 3-Year Follow-Up.

    PubMed

    Motiee-Langroudi, Maziar; Harirchi, Iraj; Amali, Amin; Jafari, Mehrdad

    2015-12-01

    To describe the authors' experience in the reconstruction of patients after total maxillectomy with preservation of orbital contents for maxillary tumors using titanium mesh and autogenous fascia lata, where no setting for free flap reconstruction is available. Twelve consecutive patients with paranasal sinus tumors underwent total maxillectomy without orbital exenterations and primary reconstruction. The defects were reconstructed by titanium mesh in combination with autogenous fascia lata in the orbital floor performed by 1 surgical team. Titanium mesh (0.2 mm thick) was contoured and fixed to reconstruct the orbital floor and obtain midface projection. Fascia lata was used to cover the titanium mesh along the orbital floor to prevent fat entrapment in the mesh holes. The most common pathology was squamous cell carcinoma (50%). Patients' mean age was 45.66 years (33 to 74 yr). The mean follow-up period was 35.2 months (30 to 49 months). During follow-up, no infection or foreign body reaction was encountered. Extrusion of titanium mesh occurred in 4 patients who underwent postoperative radiotherapy. Two cases of mild diplopia at extreme gaze occurred early during the postoperative period that resolved after a few months. Placing fascia lata between the titanium mesh surface of the orbital implant and the orbital contents was successful in preventing long-term diplopia or dystopia. Nevertheless, exposure of the titanium implant through the skin surface represented a complication of this technique in 25% of patients. Further studies are required with head-to-head comparisons of artificial materials and free flaps for reconstruction of maxillectomy defects. Copyright © 2015 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  18. [Development of ocular motility following modified 3-wall decompression of the orbita in endocrine orbitopathy for functional and rehabilitative indication].

    PubMed

    Grenzebach, Ulrike H; Schnorbus, Ulrike; Büchner, Thomas; Busse, Holger; Stoll, Wolfgang

    2003-05-01

    Permanent visual damage due to an increase in volume of the orbital contents may be the result of the failure of conservative therapeutic concepts in the treatment of endocrine orbitopathy. Considerable progress has been achieved in developing successful orbital decompression techniques with regard to functional and cosmetic outcome. Decompression techniques with resection of the bony orbital walls are adequate tools in restoring visual acuity and reducing exophthalmus. A considerable degree of deterioration of motility disorders has been described in the literature depending on the techniques being used. The purpose of this study was to investigate whether a modified technique of 3-wall orbital decompression with preservation of a medial part of the periorbital tissue to support the medial rectus muscle, is able to reduce the postoperative risk of diplopia. A modified technique of orbital 3-wall decompression with resection of the medial orbital wall, the medial orbital floor and the floor of the frontal sinus has been used in patients with compressive optic neuropathy (n = 20) and for cosmetic reasons (n = 7) in cases of uni- or bilateral proptosis. Analysis of the results was performed concerning visual outcome, exophthalmus reduction and development of horizontal and vertical motility changes. In all cases of optic neuropathy improvement of visual function at an average of 4.63 +/- 4.5 lines could be achieved. Exophthalmus reduction was 3.2 +/- 2.4 mm in the functional group and 3.9 +/- 1.7 mm in the rehabilitative group. In this group motility of the medial rectus muscle remained unaffected except in one eye. In the functional group motility deterioration was observed in 62 %. The modified 3-wall decompression technique with preservation of a medial periorbital tissue strip is an adequate alternative technique in the therapy of optic neuropathy and exophthalmus reduction in endocrine orbitopathy with a low risk of postoperative motility disorders.

  19. Analysis of facial bone fractures: An 11-year study of 2,094 patients

    PubMed Central

    Hwang, Kun; You, Sun Hye

    2010-01-01

    Purpose: The medical records of these patients were reviewed and analysed to determine the clinical characteristics and treatment of facial bone fractures. Patients and Methods: This is a retrospective study of 2,094 patients with facial bone fractures from various accidents that were treated at the Inha University Hospital from 1996 to 2007. Results: The most common age group was the third decade of life (29%). Males were more common than females (3.98:1). The most common aetiology was violent assault or nonviolent traumatic injury (49.4%). The most common isolated fracture site was the nasal bone (37.7%), followed by the mandible (30%), orbital bones (7.6%), zygoma (5.7%), maxilla (1.3%) and the frontal bone (0.3%). The largest group with complex fractures included the inferior region of the orbital floor and zygomaticomaxilla (14%). Closed reduction was performed in 46.3% of the cases while 39.7% of the cases required open reduction. For open reductions, the most commonly used soft-tissue approach was the intraoral approach (32.3%). The complication rate was 6.4% and the most common complication was hypoesthesia (68.4%) followed by diplopia (25.6%). Conclusion: Long-term collection of epidemiological data regarding facial fractures and concomitant injuries is important for the evaluation of existing preventive measures and useful in the development of new methods of injury prevention and treatment. PMID:20924449

  20. Plasma Flowfields Around Low Earth Orbit Objects: Aerodynamics to Underpin Orbit Predictions

    NASA Astrophysics Data System (ADS)

    Capon, Christopher; Boyce, Russell; Brown, Melrose

    2016-07-01

    Interactions between orbiting bodies and the charged space environment are complex. The large variation in passive body parameters e.g. size, geometry and materials, makes the plasma-body interaction in Low Earth Orbit (LEO) a region rich in fundamental physical phenomena. The aerodynamic interaction of LEO orbiting bodies with the neutral environment constitutes the largest non-conservative force on the body. However in general, study of the LEO plasma-body interaction has not been concerned with external flow physics, but rather with the effects on surface charging. The impact of ionospheric flow physics on the forces on space debris (and active objects) is not well understood. The work presented here investigates the contribution that plasma-body interactions have on the flow structure and hence on the total atmospheric force vector experienced by a polar orbiting LEO body. This work applies a hybrid Particle-in-Cell (PIC) - Direct Simulation Monte Carlo (DSMC) code, pdFoam, to self-consistently model the electrostatic flowfield about a cylinder with a uniform, fixed surface potential. Flow conditions are representative of the mean conditions experienced by the Earth Observing Satellite (EOS) based on the International Reference Ionosphere model (IRI-86). The electron distribution function is represented by a non-linear Boltzmann electron fluid and ion gas-surface interactions are assumed to be that of a neutralising, conducting, thermally accommodating solid wall with diffuse reflections. The variation in flowfield and aerodynamic properties with surface potential at a fixed flow condition is investigated, and insight into the relative contributions of charged and neutral species to the flow physics experienced by a LEO orbiting body is provided. This in turn is intended to help improve the fidelity of physics-based orbit predictions for space debris and other near-Earth space objects.

  1. Erosion of water-based fracturing fluid containing particles in a sudden contraction of horizontal pipe

    NASA Astrophysics Data System (ADS)

    Cheng, Jiarui; Cao, Yinping; Dou, Yihua; Li, Zhen

    2017-10-01

    A lab experiment was carried out to study the effects of pipe flow rate, particle concentration and pipe inner diameter ratio on proppant erosion of the reducing wall in hydraulic fracturing. The results show that the erosion rate and erosion distribution are different not only in radial direction but also in circumferential direction of the sample. The upper part of sample always has a minimum erosion rate and erosion area. Besides, the erosion rate of reducing wall is most affected by fluid flow velocity, and the erosion area is most sensitive to the change in the diameter ratio. Meanwhile, the erosion rate of reducing wall in crosslinked fracturing fluid is mainly determined by the fluid flowing state due to the high viscosity of the liquid. In general, the increase in flow velocity and diameter ratio not only cause the expansion of erosion-affected flow region in sudden contraction section, but also lead to more particles impact the wall.

  2. Kinetics of bed fracturing around mine workings

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

    Veksler, Yu.A.

    1988-03-01

    A failure of the bed near the walls of the workings of a mine away from the face occurs gradually over time and in this paper the authors take a kinetic approach to evaluating its development. The influence of certain mine engineering factors on the pattern of bed fracturing is discussed. The effect of the depth of mining is shown. Cracking occurs in the portion of the seam at the face near the ground at some distance from it on the interface between soft and hard coal. The density of the fractured rocks and their response affect the bed fracturingmore » near the stope face.« less

  3. Dynamic Y stent fractures in crescentic tracheobronchomalacia.

    PubMed

    Popilevsky, Frida; Al-Ajam, Mohammad R; Ly, Vanthanh; Sanchez, Lisette Delgado; Cutaia, Michael

    2012-07-01

    Endobronchial stents have been used occasionally to treat benign conditions such as tracheobronchomalacia (TBM). This report describes a unique case of a patient with crescentic TBM in whom Dynamic Y stent was placed on 2 separate occasions to control symptoms and resulted in identical posterior wall stent fractures within a year of stent placement, both times. A silicone Y stent was substituted for the dynamic stent, and it has been effective in controlling symptoms for 9 months without complications. A literature review of cases of fractured Dynamic Y stents is made and factors affecting the choice of stent type for crescentic TBM are explored.

  4. The Bulging Behavior of Thick-Walled 6063 Aluminum Alloy Tubes Under Double-Sided Pressures

    NASA Astrophysics Data System (ADS)

    Cui, Xiao-Lei; Wang, Xiao-Song; Yuan, Shi-Jian

    2015-05-01

    To make further exploration on the deformation behavior of tube under double-sided pressures, the thick-walled 6063 aluminum alloy tubes with an outer diameter of 65 mm and an average thickness of 7.86 mm have been used to be bulged under the combined action of internal and external pressures. In the experiment, two ends of the thick-walled tubes were fixed using the tooth and groove match. Three levels of external pressure (0 MPa, 40 MPa, and 80 MPa), in conjunction with the internal pressure, were applied on the tube outside and inside simultaneously. The effect of external pressure on the bulging behavior of the thick-walled tubes, such as the limiting expansion ratio, the bulging zone profile, and the thickness distribution, has been investigated. It is shown that the limiting expansion ratio, the bulging zone profile, and the thickness distribution in the homogeneous bulging area are all insensitive to the external pressure. However, the external pressure can make the thick-walled tube achieve a thinner wall at the fracture area. It reveals that the external pressure can only improve the fracture limit of the thick-walled 6063 tubes, but it has very little effect on their homogeneous bulging behavior. It might be because the external pressure can only increase the magnitude of the hydrostatic pressure for the tube but has no effect on the Lode parameter.

  5. Fracture development within a stratovolcano: The Karaha-Telaga Bodas geothermal field, Java volcanic arc

    USGS Publications Warehouse

    Nemcok, M.; Moore, J.N.; Allis, R.; McCulloch, J.

    2004-01-01

    -salinity meteoric water entered the marginal parts of the system. Calcite, anhydrite and fluorite precipitated in fractures on heating. Progressive sealing of the fractures resulted in the downward migration of the cap rock. In response to decreased pore pressure in the expanding vapour zone, walls of the fracture system within the vapour-dominated reservoir progressively collapsed. It left only residual permeability in the remaining fracture volume, with apertures supported only by asperities or propping breccia. In places where normal stresses acting on the fracture walls exceeded the compressive strength of the wall rock, the fractures have completely collapsed. Fractures within the present-day cap rock include strike- and oblique-slip faults, normal faults and tensile fractures, all controlled by a strike-slip stress regime. The reservoir is characterized by normal faults and tensile fractures controlled by a normal-fault stress regime. The fractures show no evidence that the orientation of the stress field has changed since fracture propagation began. Fluid migration in the lava and pyroclastic flows is controlled by fractures. Matrix permeability controls fluid flow in the sedimentary sections of the reservoir. Productive fractures are typically roughly perpendicular to the minimum compressive stress, ??3, and are prone to slip and dilation within the modern stress regime. ?? The Geological Society of London 2004.

  6. A Novel Fixation System for Acetabular Quadrilateral Plate Fracture: A Comparative Biomechanical Study

    PubMed Central

    Zha, Guo-Chun; Sun, Jun-Ying; Dong, Sheng-Jie; Zhang, Wen; Luo, Zong-Ping

    2015-01-01

    This study aims to assess the biomechanical properties of a novel fixation system (named AFRIF) and to compare it with other five different fixation techniques for quadrilateral plate fractures. This in vitro biomechanical experiment has shown that the multidirectional titanium fixation (MTF) and pelvic brim long screws fixation (PBSF) provided the strongest fixation for quadrilateral plate fracture; the better biomechanical performance of the AFRIF compared with the T-shaped plate fixation (TPF), L-shaped plate fixation (LPF), and H-shaped plate fixation (HPF); AFRIF gives reasonable stability of treatment for quadrilateral plate fracture and may offer a better solution for comminuted quadrilateral plate fractures or free floating medial wall fracture and be reliable in preventing protrusion of femoral head. PMID:25802849

  7. Land-Surface Subsidence and Open Bedrock Fractures in the Tully Valley, Onondaga County, New York

    USGS Publications Warehouse

    Hackett, William R.; Gleason, Gayle C.; Kappel, William M.

    2009-01-01

    Open bedrock fractures were mapped in and near two brine field areas in Tully Valley, New York. More than 400 open fractures and closed joints were mapped for dimension, orientation, and distribution along the east and west valley walls adjacent to two former brine fields. The bedrock fractures are as much as 2 feet wide and over 50 feet deep, while linear depressions in the soil, which are 3 to 10 feet wide and 3 to 6 feet deep, indicate the presence of open bedrock fractures below the soil. The fractures are probably the result of solution mining of halite deposits about 1,200 feet below the land surface.

  8. Application of the boundary elements method for modeling of the fracture of cylindrical bodies by hydraulic fracturing

    NASA Astrophysics Data System (ADS)

    Legan, M. A.; Blinov, V. A.; Larichkin, A. Yu; Novoselov, A. N.

    2017-10-01

    Experimental study of hydraulic fracturing of thick-walled cylinders with a central circular hole was carried out using the machine that creates a high oil pressure. Experiments on the compression fracture of the solid cylinders by diameter and rectangular parallelepipeds perpendicular to the ends were carried out with a multipurpose test machine Zwick / Roell Z100. Samples were made of GF-177 material based on cement. Ultimate stresses in the material under study were determined for three types of stress state: under compression, with a pure shear on the surface of the hole under frecking conditions and under a compound stress state under conditions of diametral compression of a solid cylinder. The value of the critical stress intensity factor of GF-177 material was obtained. The modeling of the fracturing process taking into account the inhomogeneity of the stress state near the hole was carried out using the boundary elements method (in the variant of the fictitious load method) and the gradient fracture criterion. Calculation results of the ultimate pressure were compared with values obtained analytically on the basis of the Lame solution and with experimental data.

  9. Pyroclastic Deposits in the Floor-fractured Crater Alphonsus

    NASA Technical Reports Server (NTRS)

    Allen, Carlton C.; Donaldson-Hanna, Kerri L.; Pieters, Carle M.; Moriarty, Daniel P.; Greenhagen, Benjamin T.; Bennett, Kristen A.; Kramer, Georgiana Y.; Paige, David A.

    2013-01-01

    Alphonsus, the 118 km diameter floor-fractured crater, is located immediately east of Mare Nubium. Eleven pyroclastic deposits have been identified on the crater's floor. Early telescopic spectra suggest that the floor of Alphonsus is noritic, and that the pyroclastic deposits contain mixtures of floor material and a juvenile component including basaltic glass. Head and Wilson contend that Nubium lavas intruded the breccia zone beneath Alphonsus, forming dikes and fractures on the crater floor. In this model, the magma ascended to the level of the mare but cooled underground, and a portion broke thru to the surface in vulcanian (explosive) eruptions. Alternatively, the erupted material could be from a source unrelated to the mare, in the style of regional pyroclastic deposits. High-resolution images and spectroscopy from the Moon Mineralogy Mapper (M3), Diviner Lunar Radiometer, and Lunar Reconnaissance Orbiter Camera Narrow Angle Camera (NAC) provide data to test these formation models. Spectra from M3 confirm that the crater floor is primarily composed of noritic material, and that the Nubium lavas are basaltic. Spectra from the three largest pyroclastic deposits in Alphonsus are consistent with a minor low- Ca pyroxene component in a glass-rich matrix. The centers of the 2 micron absorption bands have wavelengths too short to be of the same origin as the Nubium basalts. Diviner Christiansen feature (CF) values were used to estimate FeO abundances for the crater floor, Nubium soil, and pyroclastic deposits. The estimated abundance for the crater floor (7.5 +/- 1.4 wt.%) is within the range of FeO values for Apollo norite samples. However, the estimated FeO abundance for Nubium soil (13.4 +/- 1.4 wt.%) is lower than those measured in most mare samples. The difference may reflect contamination of the mare soil by highland ejecta. The Diviner-derived FeO abundance for the western pyroclastic deposit is 13.8 +/- 3.3 wt.%. This is lower than the values for mare soil

  10. Improving the fracture toughness and the strength of epoxy using nanomaterials--a review of the current status.

    PubMed

    Domun, N; Hadavinia, H; Zhang, T; Sainsbury, T; Liaghat, G H; Vahid, S

    2015-06-21

    The incorporation of nanomaterials in the polymer matrix is considered to be a highly effective technique to improve the mechanical properties of resins. In this paper the effects of the addition of different nanoparticles such as single-walled CNT (SWCNT), double-walled CNT (DWCNT), multi-walled CNT (MWCNT), graphene, nanoclay and nanosilica on fracture toughness, strength and stiffness of the epoxy matrix have been reviewed. The Young's modulus (E), ultimate tensile strength (UTS), mode I (GIC) and mode II (GIIC) fracture toughness of the various nanocomposites at different nanoparticle loadings are compared. The review shows that, depending on the type of nanoparticles, the integration of the nanoparticles has a substantial effect on mode I and mode II fracture toughness, strength and stiffness. The critical factors such as maintaining a homogeneous dispersion and good adhesion between the matrix and the nanoparticles are highlighted. The effect of surface functionalization, its relevancy and toughening mechanism are also scrutinized and discussed. A large variety of data comprised of the mechanical properties of nanomaterial toughened composites reported to date has thus been compiled to facilitate the evolution of this emerging field, and the results are presented in maps showing the effect of nanoparticle loading on mode I fracture toughness, stiffness and strength.

  11. Ground penetrating radar for fracture mapping in underground hazardous waste disposal sites: A case study from an underground research tunnel, South Korea

    NASA Astrophysics Data System (ADS)

    Baek, Seung-Ho; Kim, Seung-Sep; Kwon, Jang-Soon; Um, Evan Schankee

    2017-06-01

    Secure disposal or storage of nuclear waste within stable geologic environments hinges on the effectiveness of artificial and natural radiation barriers. Fractures in the bedrock are viewed as the most likely passage for the transport of radioactive waste away from a disposal site. We utilize ground penetrating radar (GPR) to map fractures in the tunnel walls of an underground research tunnel at the Korea Atomic Energy Research Institute (KAERI). GPR experiments within the KAERI Underground Research Tunnel (KURT) were carried out by using 200 MHz, 500 MHz, and 1000 MHz antennas. By using the high-frequency antennas, we were able to identify small-scale fractures, which were previously unidentified during the tunnel excavation process. Then, through 3-D visualization of the grid survey data, we reconstructed the spatial distribution and interconnectivity of the multi-scale fractures within the wall. We found that a multi-frequency GPR approach provided more details of the complex fracture network, including deep structures. Furthermore, temporal changes in reflection polarity between the GPR surveys enabled us to infer the hydraulic characteristics of the discrete fracture network developed behind the surveyed wall. We hypothesized that the fractures exhibiting polarity change may be due to a combination of air-filled and mineralogical boundaries. Simulated GPR scans for the considered case were consistent with the observed GPR data. If our assumption is correct, the groundwater flow into these near-surface fractures may form the water-filled fractures along the existing air-filled ones and hence cause the changes in reflection polarity over the given time interval (i.e., 7 days). Our results show that the GPR survey is an efficient tool to determine fractures at various scales. Time-lapse GPR data may be essential to characterize the hydraulic behavior of discrete fracture networks in underground disposal facilities.

  12. Posttraumatic subperiosteal hematomas of the orbit in children.

    PubMed

    Yazici, Bülent; Gönen, Tansu

    2011-01-01

    To describe 5 pediatric patients with traumatic orbital subperiosteal hematoma and review the relevant literature. Retrospective chart analysis of 5 children with posttraumatic subperiosteal hematoma and a systematic review of the English language literature. Five new pediatric cases of orbital subperiosteal hematoma are presented with varying clinical and radiologic manifestations and treatments. Literature review (including the current 5 cases) yielded 23 cases in total. Eighteen (78%) of the patients were boys, and 5 (22%) were girls. The children ranged in age from 5 to 17 years, with the mean and median ages being 12 years. The leading cause was blunt trauma related to falls or direct impact. Two patients (9%) had an inherited coagulopathy, predisposing them to orbital hemorrhage. The hematomas developed in the superior orbit in all cases except one. In 3 patients (13%), orbital hematomas were bilateral. In 9 patients (39%), the hematomas extended in subgaleal or frontal subdural spaces. In 7 patients (30%), subperiosteal hematoma was associated with compressive optic neuropathy. Four patients (17%) had a nondisplaced orbital roof fracture. Seventeen patients were treated with surgical evacuation of hematoma (52%) or with needle aspiration (22%), and 5 patients (22%) were observed for spontaneous resolution. Three patients (13%) experienced a recurrence of hemorrhage. In children, traumatic subperiosteal hematomas of the orbit typically occur after blunt trauma in the superior orbit. The risk of compressive optic neuropathy may be higher in patients with bilateral hematoma and massive subgaleal hematoma. Most patients are treated with evacuation of the hematoma.

  13. Managment of frontal sinus fracture: obliteration sinus with cancellous bone graft.

    PubMed

    Muminagic, Sahib; Masic, Tarik; Babajic, Emina; Asotic, Mithat

    2011-01-01

    Frontal sinus fractures make up about 2-15% of all facial fractures.This is relatively low frequency of occurrence, but it has a large potential of complication and may involve not only the frontal sinuse but more importantly the brain and the eyes. The management depends of the complexity. If anterior wall is fractured with grossly involved nasofrontal duct (NFD) in the injury it is paramount to occlude NFD. Very often, sinus obliteration is done at the same time. In our expirience autogenous cancellous bone graft is considered to be the best grafting material. It has the less short - or long-term complications and the donor site morbidity is insignificant.

  14. Orbital motions of bubbles in an acoustic field

    NASA Astrophysics Data System (ADS)

    Shirota, Minori; Yamashita, Ko; Inamura, Takao

    2012-09-01

    This experimental study aims to clarify the mechanism of orbital motion of two oscillating bubbles in an acoustic field. Trajectory of the orbital motion on the wall of a spherical levitator was observed using a high-speed video camera. Because of a good repeatability in volume oscillation of bubbles, we were also able to observe the radial motion driven at 24 kHz by stroboscopic like imaging technique. The orbital motions of bubbles raging from 0.13 to 0.18 mm were examined with different forcing amplitude and in different viscous oils. As a result, we found that pairs of bubbles revolve along an elliptic orbit around the center of mass of the bubbles. We also found that the two bubbles perform anti-phase radial oscillation. Although this radial oscillation should result in a repulsive secondary Bjerknes force, the bubbles kept a constant separate distance of about 1 mm, which indicates the existence of centripetal primary Bjerknes force.

  15. Aspects of the Fracture Toughness of Carbon Nanotube Modified Epoxy Polymer Composites

    NASA Astrophysics Data System (ADS)

    Mirjalili, Vahid

    Epoxy resins used in fibre reinforced composites exhibit a brittle fracture behaviour, because they show no sign of damage prior to a catastrophic failure. Rubbery materials and micro-particles have been added to epoxy resins to improve their fracture toughness, which reduces strength and elastic properties. In this research, carbon nanotubes (CNTs) are investigated as a potential toughening agent for epoxy resins and carbon fibre reinforced composites, which can also enhance strength and elastic properties. More specifically, the toughening mechanisms of CNTs are investigated theoretically and experimentally. The effect of aligned and randomly oriented carbon nanotubes (CNTs) on the fracture toughness of polymers was modelled using Elastic Plastic Fracture Mechanics. Toughening from CNT pull-out and rupture were considered, depending on the CNTs critical length. The model was used to identify the effect of CNTs geometrical and mechanical properties on the fracture toughness of CNT-modified epoxies. The modelling results showed that a uniform dispersion and alignment of a high volume fraction of CNTs normal to the crack growth plane would lead to the maximum fracture toughness enhancement. To achieve a uniform dispersion, the effect of processing on the dispersion of single walled and multi walled CNTs in epoxy resins was investigated. An instrumented optical microscope with a hot stage was used to quantify the evolution of the CNT dispersion during cure. The results showed that the reduction of the resin viscosity at temperatures greater than 100 °C caused an irreversible re-agglomeration of the CNTs in the matrix. The dispersion quality was then directly correlated to the fracture toughness of the modified resin. It was shown that the fine tuning of the ratio of epoxy resin, curing agent and CNT content was paramount to the improvement of the base resin fracture toughness. For the epoxy resin (MY0510 from Hexcel), an improvement of 38% was achieved with 0.3 wt

  16. An Approach to Estimate the Flow Through an Irregular Fracture

    NASA Astrophysics Data System (ADS)

    Liu, Q. Q.; Fan, H. G.

    2011-09-01

    A new model to estimate the flow in a fracture has been developed in this paper. This model used two sinusoidal-varying walls with different phases to replace the flat planes in the cubic law model. The steady laminar flow between non-symmetric sinusoidal surfaces was numerically solved. The relationships between the effective hydraulic apertures and the phase retardation for different amplitudes and wavelengths are investigated respectively. Finally, a formula of the effective hydraulic aperture of the fracture was carried out based on the numerical results.

  17. Successful medical treatment of an orbital osteoma in a dog.

    PubMed

    Grozdanic, Sinisa; Riedesel, Elizabeth A; Ackermann, Mark R

    2013-03-01

    A 6-year-old neutered male German Shepherd-mixed breed with a 2-month history of bilateral conjunctival hyperemia, epiphora, and a firm, slowly progressive swelling of the medial canthal region of the left eye (OS) was examined. Ophthalmic examination OS revealed a firm and smooth mass, extending from the medial canthus toward the medial orbital wall. Indirect ophthalmoscopy revealed indentation of the nasal part OS, which corresponded to the position of the orbital mass. Orbital neoplastic diseases were the main differential considerations. Computerized tomography revealed a bony smooth orbital mass without bone destructive features. Biopsy was performed, and histologic features were suggestive of osteoma. Systemic nonsteroidal anti-inflammatory (NSAID) drugs resulted in complete mass regression and absence of clinical signs for 5 years following initial diagnosis. This report describes the first case of canine orbital osteoma, which was responsive to NSAIDs. © 2012 American College of Veterinary Ophthalmologists.

  18. Evolution of Friction and Permeability in a Propped Fracture under Shear

    DOE PAGES

    Zhang, Fengshou; Fang, Yi; Elsworth, Derek; ...

    2017-12-04

    We explore the evolution of friction and permeability of a propped fracture under shear. We examine the effects of normal stress, proppant thickness, proppant size, and fracture wall texture on the frictional and transport response of proppant packs confined between planar fracture surfaces. The proppant-absent and proppant-filled fractures show different frictional strength. For fractures with proppants, the frictional response is mainly controlled by the normal stress and proppant thickness. The depth of shearing-concurrent striations on fracture surfaces suggests that the magnitude of proppant embedment is controlled by the applied normal stress. Under high normal stress, the reduced friction implies thatmore » shear slip is more likely to occur on propped fractures in deeper reservoirs. The increase in the number of proppant layers, from monolayer to triple layers, significantly increases the friction of the propped fracture due to the interlocking of the particles and jamming. Permeability of the propped fracture is mainly controlled by the magnitude of the normal stress, the proppant thickness, and the proppant grain size. Permeability of the propped fracture decreases during shearing due to proppant particle crushing and related clogging. Proppants are prone to crushing if the shear loading evolves concurrently with the normal loading.« less

  19. Evolution of Friction and Permeability in a Propped Fracture under Shear

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

    Zhang, Fengshou; Fang, Yi; Elsworth, Derek

    We explore the evolution of friction and permeability of a propped fracture under shear. We examine the effects of normal stress, proppant thickness, proppant size, and fracture wall texture on the frictional and transport response of proppant packs confined between planar fracture surfaces. The proppant-absent and proppant-filled fractures show different frictional strength. For fractures with proppants, the frictional response is mainly controlled by the normal stress and proppant thickness. The depth of shearing-concurrent striations on fracture surfaces suggests that the magnitude of proppant embedment is controlled by the applied normal stress. Under high normal stress, the reduced friction implies thatmore » shear slip is more likely to occur on propped fractures in deeper reservoirs. The increase in the number of proppant layers, from monolayer to triple layers, significantly increases the friction of the propped fracture due to the interlocking of the particles and jamming. Permeability of the propped fracture is mainly controlled by the magnitude of the normal stress, the proppant thickness, and the proppant grain size. Permeability of the propped fracture decreases during shearing due to proppant particle crushing and related clogging. Proppants are prone to crushing if the shear loading evolves concurrently with the normal loading.« less

  20. Micromagnetic analysis of current-induced domain wall motion in a bilayer nanowire with synthetic antiferromagnetic coupling

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

    Komine, Takashi, E-mail: komine@mx.ibaraki.ac.jp; Aono, Tomosuke

    We demonstrate current-induced domain wall motion in bilayer nanowire with synthetic antiferromagnetic (SAF) coupling by modeling two body problems for motion equations of domain wall. The influence of interlayer exchange coupling and magnetostatic interactions on current-induced domain wall motion in SAF nanowires was also investigated. By assuming the rigid wall model for translational motion, the interlayer exchange coupling and the magnetostatic interaction between walls and domains in SAF nanowires enhances domain wall speed without any spin-orbit-torque. The enhancement of domain wall speed was discussed by energy distribution as a function of wall angle configuration in bilayer nanowires.

  1. Roothaan's approach to solve the Hartree-Fock equations for atoms confined by soft walls: Basis set with correct asymptotic behavior.

    PubMed

    Rodriguez-Bautista, Mariano; Díaz-García, Cecilia; Navarrete-López, Alejandra M; Vargas, Rubicelia; Garza, Jorge

    2015-07-21

    In this report, we use a new basis set for Hartree-Fock calculations related to many-electron atoms confined by soft walls. One- and two-electron integrals were programmed in a code based in parallel programming techniques. The results obtained with this proposal for hydrogen and helium atoms were contrasted with other proposals to study just one and two electron confined atoms, where we have reproduced or improved the results previously reported. Usually, an atom enclosed by hard walls has been used as a model to study confinement effects on orbital energies, the main conclusion reached by this model is that orbital energies always go up when the confinement radius is reduced. However, such an observation is not necessarily valid for atoms confined by penetrable walls. The main reason behind this result is that for atoms with large polarizability, like beryllium or potassium, external orbitals are delocalized when the confinement is imposed and consequently, the internal orbitals behave as if they were in an ionized atom. Naturally, the shell structure of these atoms is modified drastically when they are confined. The delocalization was an argument proposed for atoms confined by hard walls, but it was never verified. In this work, the confinement imposed by soft walls allows to analyze the delocalization concept in many-electron atoms.

  2. [Internal fixation treatment of multiple rib fractures with absorbable rib-connecting-pins under epidural anesthesia].

    PubMed

    Liu, Jinliang; Li, Keyao; Ju, Zhenlong; Bai, Yan

    2011-03-01

    To study the indications, methods and experience of absorbable rib-connecting-pins fixation in the treatment of multiple rib fractures. 52 cases with multiple rib fractures were performed internal fixation with absorbable rib-connecting-pins under epidural anesthesia. All cases were followed up for 1 to 12 months, with an average of 5 months. All fractures were achieved healing in 3 to 6 months after the operation and were not found chest wall deformity. Absorbable rib-connecting-pins fixation is a simple and effective method and worthies recommending to perform operation for the appropriate cases with multiple rib fractures.

  3. Modelling of Local Necking and Fracture in Aluminium Alloys

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

    Achani, D.; Eriksson, M.; Hopperstad, O. S.

    2007-05-17

    Non-linear Finite Element simulations are extensively used in forming and crashworthiness studies of automotive components and structures in which fracture need to be controlled. For thin-walled ductile materials, the fracture-related phenomena that must be properly represented are thinning instability, ductile fracture and through-thickness shear instability. Proper representation of the fracture process relies on the accuracy of constitutive and fracture models and their parameters that need to be calibrated through well defined experiments. The present study focuses on local necking and fracture which is of high industrial importance, and uses a phenomenological criterion for modelling fracture in aluminium alloys. As anmore » accurate description of plastic anisotropy is important, advanced phenomenological constitutive equations based on the yield criterion YLD2000/YLD2003 are used. Uniaxial tensile tests and disc compression tests are performed for identification of the constitutive model parameters. Ductile fracture is described by the Cockcroft-Latham fracture criterion and an in-plane shear tests is performed to identify the fracture parameter. The reason is that in a well designed in-plane shear test no thinning instability should occur and it thus gives more direct information about the phenomenon of ductile fracture. Numerical simulations have been performed using a user-defined material model implemented in the general-purpose non-linear FE code LS-DYNA. The applicability of the model is demonstrated by correlating the predicted and experimental response in the in-plane shear tests and additional plane strain tension tests.« less

  4. MGS Mars Orbiter Laser Altimeter (MOLA) - Mars/Earth Relief Comparison

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Comparison of the cross-sectional relief of the deepest portion of the Grand Canyon (Arizona) on Earth versus a Mars Orbiter Laser Altimeter (MOLA) view of a common type of chasm on Mars in the western Elysium region. The MOLA profile was collected during the Mars Global Surveyor Capture Orbit Calibration Pass on September 15, 1997. The Grand Canyon topography is shown as a trace with a measurement every 295 feet (90 meters) along track, while that from MOLA reflects measurements about every 970 feet (400 meters) along track. The slopes of the steep inner canyon wall of the Martian feature exceed the angle of repose, suggesting relative youth and the potential for landslides. The inner wall slopes of the Grand Canyon are less than those of the Martian chasm, reflecting the long period of erosion necessary to form its mile-deep character on Earth.

  5. Surveyed opinion of American trauma, orthopedic, and thoracic surgeons on rib and sternal fracture repair.

    PubMed

    Mayberry, John C; Ham, L Bruce; Schipper, Paul H; Ellis, Thomas J; Mullins, Richard J

    2009-03-01

    Rib and sternal fracture repair are controversial. The opinion of surgeons regarding those patients who would benefit from repair is unknown. Members of the Eastern Association for the Surgery of Trauma, the Orthopedic Trauma Association, and thoracic surgeons (THS) affiliated with teaching hospitals in the United States were recruited to complete an electronic survey regarding rib and sternal fracture repair. Two hundred thirty-eight trauma surgeons (TRS), 97 orthopedic trauma surgeons (OTS), and 70 THS completed the survey. Eighty-two percent of TRS, 66% of OTS, and 71% of THS thought that rib fracture repair was indicated in selected patients. A greater proportion of surgeons thought that sternal fracture repair was indicated in selected patients (89% of TRS, 85% of OTS, and 95% of THS). Chest wall defect/pulmonary hernia (58%) and sternal fracture nonunion (>6 weeks) (68%) were the only two indications accepted by a majority of respondents. Twenty-six percent of surgeons reported that they had performed or assisted on a chest wall fracture repair, whereas 22% of surgeons were familiar with published randomized trials of the surgical repair of flail chest. Of surgeons who thought rib fracture or sternal fracture repair was rarely, if ever, indicated, 91% and 95%, respectively, specified that a randomized trial confirming efficacy would be necessary to change their negative opinion. A majority of surveyed surgeons reported that rib and sternal fracture repair is indicated in selected patients; however, a much smaller proportion indicated that they had performed the procedures. The published literature on surgical repair is sparse and unfamiliar to most surgeons. Barriers to surgical repair of rib and sternal fracture include a lack of expertise among TRS, lack of research of optimal techniques, and a dearth of randomized trials.

  6. Examination of life-threatening injuries in 431 pediatric facial fractures at a level 1 trauma center.

    PubMed

    Hoppe, Ian C; Kordahi, Anthony M; Paik, Angie M; Lee, Edward S; Granick, Mark S

    2014-09-01

    Pediatric facial fractures represent a challenge in management due to the unique nature of the growing facial skeleton. Oftentimes, more conservative measures are favored to avoid rigid internal fixation and disruption of blood supply to the bone and soft tissues. In addition, the great force required to fracture bones of the facial skeleton often produces concomitant injuries that present a management priority. The purpose of this study was to examine a level 1 trauma center's experience with pediatric facial trauma resulting in fractures of the underlying skeleton with regards to epidemiology and concomitant injuries. A retrospective review of all facial fractures at a level 1 trauma center in an urban environment was performed for the years 2000 to 2012. Patients aged 18 years or younger were included. Patient demographics were collected, as well as location of fractures, concomitant injuries, and surgical management strategies. A significance value of 5% was used. During this period, there were 3147 facial fractures treated at our institution, 353 of which were pediatric patients. Upon further review, 68 patients were excluded because of insufficient data for analysis, leaving 285 patients for review. The mean age of patients was 14.2 years with a male predominance (77.9%). The mechanism of injury was assault in 108 (37.9%), motor vehicle accident in 68 (23.9%), pedestrian struck in 41 (14.4%), fall in 26 (9.1%), sporting accident in 20 (7.0%), and gunshot injury in 16 (5.6%). The mean Glasgow Coma Scale (GCS) on arrival to the emergency department was 13.7. The most common fractures were those of the mandible (29.0%), orbit (26.5%), nasal bone (14.4%), zygoma (7.7%), and frontal bone/frontal sinus (7.5%). Intracranial hemorrhage was present in 70 patients (24.6%). A skull fracture was present in 50 patients (17.5%). A long bone fracture was present in 36 patients (12.6%). A pelvic or thoracic fracture was present in 30 patients (10.5%). A cervical spine

  7. The Orbital Workshop Sleep Compartment

    NASA Technical Reports Server (NTRS)

    1972-01-01

    This wide-angle view is of the Orbital Workshop (OWS) sleep compartment, located in the lower level of the OWS. Each crewman was assigned a small space for sleeping and zipped themselves into sleeping bags stretched against the wall. Because of the absence of gravity, sleeping comfort was achieved in any position relative to the spacecraft; body support was not necessary. Sleeping could be accommodated quite comfortably in a bag that held the body at a given place in Skylab.

  8. Transport and Clogging of Particulate Flow in Fracture Systems

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

    Koplik, Joel

    The aim of the project is to understand the effects of confinement in narrow rough-walled fractures on the transport behavior of fluids and suspended particles in subsurface hydro- carbon reservoirs. A key motivation for the study is that such fracture systems provide the highest throughput in oil and gas extraction and have been the focus of recent industrial activity. The scientific challenge is to understand how the confined geometry alters transport phenomena, and in particular its influence on (diagnostic) tracer transport and the effects of flow channeling and clogging on fluid motion. An important complicating feature of geological fractures ismore » the self-affine fractal nature of their surface roughness, leading to irregular but correlated fluid and particle motion. The key technique used is computer simulation, augmented by analytical calculations and collaboration with outside experimental colleagues when possible. The principal topics studied were fluid permeability, tracer dispersion, flow channeling and anisotropy, particle transport in narrow channels and particle trapping in tight fractures.« less

  9. Fronto-orbital feminization technique. A surgical strategy using fronto-orbital burring with or without eggshell technique to optimize the risk/benefit ratio.

    PubMed

    Villepelet, A; Jafari, A; Baujat, B

    2018-05-04

    The demand for facial feminization is increasing in transsexual patients. Masculine foreheads present extensive supraorbital bossing with a more acute glabellar angle, whereas female foreheads show softer features. The aim of this article is to describe our surgical technique for fronto-orbital feminization. The mask-lift technique is an upper face-lift. It provides rejuvenation by correcting collapsed features, and fronto-orbital feminization through burring of orbital rims and lateral canthopexies. Depending on the size of the frontal sinus and the thickness of its anterior wall, frontal remodeling is achieved using simple burring or by means of the eggshell technique. Orbital remodeling comprises a superolateral orbital opening, a reduction of ridges and a trough at the lateral orbital rim to support the lateral canthopexy. Frontal, corrugator and procerus myectomies, plus minimal scalp excision, complete the surgery. Our technique results in significant, natural-looking feminization. No complications were observed in our series of patients. The eggshell technique is an alternative to bone flap on over-pneumatized sinus. Fronto-orbital feminization fits into a wider surgical strategy. It can be associated to rhinoplasty, genioplasty, mandibular angle remodeling, face lift and laryngoplasty. Achieving facial feminization in 2 or 3 stages improves psychological and physiological tolerance. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  10. [Bone cement implant as an alternative for orbital floor reconstruction: A case report].

    PubMed

    Vargas-Solalinde, Enrique; Huichapa-Padilla, Marisol E; Garza-Cantú, Daniel; Reyna-Martínez, Víctor H; Alatorre-Ricardo, Julio; González-Treviño, Juan Luis

    2017-12-01

    The management of orbitary fractures is one of the most challenging in facial trauma; the variety of reconstruction materials for its treatment is broad and is constantly improving, but despite this there is no consensus for its use or literature that sustains it. To present the use and design of a preformed bone implant as an alternative for the reconstruction of orbital floor fractures in the pediatric age group. A 7-year old male who suffered a right hemifacial contusion trauma with clinical and tomographic diagnosis of right pure blowout type orbital floor fracture with inferior rectus muscle entrapment and right post-traumatic palpebral ptosis. Successful surgical reconstruction was performed 7 days later with a pre-constructed bone cement implant. Eight weeks after surgery the patient presented with mild residual palpebral ptosis, no ocular movement limitations and no diplopia. The use of a bone cement implant can be considered appropriate for the reconstruction of these fractures, as another alternative to be used by the ophthalmologist among the variety of all the other materials used for this purpose. We consider that our optimism based on the results obtained in this case obligates us to increase the number of patients treated in order to gather more evidence and do larger follow up. Copyright © 2016 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.

  11. Ductile fracture of cylindrical vessels containing a large flaw

    NASA Technical Reports Server (NTRS)

    Erdogan, F.; Irwin, G. R.; Ratwani, M.

    1976-01-01

    The fracture process in pressurized cylindrical vessels containing a relatively large flaw is considered. The flaw is assumed to be a part-through or through meridional crack. The flaw geometry, the yield behavior of the material, and the internal pressure are assumed to be such that in the neighborhood of the flaw the cylinder wall undergoes large-scale plastic deformations. Thus, the problem falls outside the range of applicability of conventional brittle fracture theories. To study the problem, plasticity considerations are introduced into the shell theory through the assumptions of fully-yielded net ligaments using a plastic strip model. Then a ductile fracture criterion is developed which is based on the concept of net ligament plastic instability. A limited verification is attempted by comparing the theoretical predictions with some existing experimental results.

  12. Non-perturbative modelling of energetic particle effects on resistive wall mode: Anisotropy and finite orbit width

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

    Liu, Yueqiang, E-mail: yueqiang.liu@ccfe.ac.uk; Chapman, I. T.; Graves, J. P.

    2014-05-15

    A non-perturbative magnetohydrodynamic-kinetic hybrid formulation is developed and implemented into the MARS-K code [Liu et al., Phys. Plasmas 15, 112503 (2008)] that takes into account the anisotropy and asymmetry [Graves et al., Nature Commun. 3, 624 (2012)] of the equilibrium distribution of energetic particles (EPs) in particle pitch angle space, as well as first order finite orbit width (FOW) corrections for both passing and trapped EPs. Anisotropic models, which affect both the adiabatic and non-adiabatic drift kinetic energy contributions, are implemented for both neutral beam injection and ion cyclotron resonant heating induced EPs. The first order FOW correction does notmore » contribute to the precessional drift resonance of trapped particles, but generally remains finite for the bounce and transit resonance contributions, as well as for the adiabatic contributions from asymmetrically distributed passing particles. Numerical results for a 9MA steady state ITER plasma suggest that (i) both the anisotropy and FOW effects can be important for the resistive wall mode stability in ITER plasmas; and (ii) the non-perturbative approach predicts less kinetic stabilization of the mode, than the perturbative approach, in the presence of anisotropy and FOW effects for the EPs. The latter may partially be related to the modification of the eigenfunction of the mode by the drift kinetic effects.« less

  13. Floor-fractured craters on Ceres and implications for interior processes

    NASA Astrophysics Data System (ADS)

    Buczkowski, Debra; Schenk, Paul M.; Scully, Jennifer E. C.; Park, Ryan; Preusker, Frank; Raymond, Carol; Russell, Christopher T.

    2016-10-01

    Several of the impact craters on Ceres have patterns of fractures on their floors. These fractures appear similar to those found within a class of lunar craters referred to as Floor-Fractured Craters (FFCs) [Schultz, 1976].Lunar FFCs are characterized by anomalously shallow floors cut by radial, concentric, and/or polygonal fractures, and have been classified into crater classes, Types 1 through 6, based on their morphometric properties [Schultz, 1976; Jozwiak et al, 2012, 2015]. Models for their formation have included both floor uplift due to magmatic intrusion below the crater or floor shallowing due to viscous relaxation. However, the observation that the depth versus diameter (d/D) relationship of the FFCs is distinctly shallower than the same association for other lunar craters supports the hypotheses that the floor fractures form due to shallow magmatic intrusion under the crater [Jozwiak et al, 2012, 2015].FFCs have also been identified on Mars [Bamberg et al., 2014]. Martian FFCs exhibit morphological characteristics similar to the lunar FFCs, and analyses suggest that the Martian FCCs also formed due to volcanic activity, although heavily influenced by interactions with groundwater and/or ice.We have cataloged the Ceres FFCs according to the classification scheme designed for the Moon. Large (>50 km) Ceres FFCs are most consistent with Type 1 lunar FFCs, having deep floors, central peaks, wall terraces, and radial and/or concentric fractures. Smaller craters on Ceres are more consistent with Type 4 lunar FFCs, having less-pronounced floor fractures and a v-shaped moats separating the wall scarp from the crater interior.An analysis of the d/D ratio for Ceres craters shows that, like lunar FFCs, the Ceres FFCs are anomalously shallow. This suggests that the fractures on the floor of Ceres FFCs may be due the intrusion of a low-density material below the craters that is uplifting their floors. While on the Moon and Mars the intrusive material is hypothesized

  14. Major neurovascular complications of clavicle fracture surgery

    PubMed Central

    Clitherow, Harry DS

    2014-01-01

    Clavicle fracture fixation is becoming an increasingly common operation, with good clinical outcomes and a low rate of significant complications. However, there are several reports of rare but potentially life or limb threatening, neurovascular complications. Arterial injuries are usually pseudoaneurysms associated with prominent screws. These may be clinically silent for several years before presenting as subcritical upper limb ischaemia. Venous injuries are a result of tearing of the vessel wall by fracture manipulation, drills or implants. This produces intra-operative haemorrhage and potentially air embolism, which can be fatal if not rapidly recognized and managed. Brachial plexopathy is the result of traction on adherent plexus or impingement by fracture fragments or callus. It presents as severe arm pain and paralysis immediately postoperatively. Neurovascular injuries can be avoided by a combination of pre-operative planning, communication with anaesthetic staff and strategic surgical technique. The plane of the surgical exposure, release of the soft tissues, drill direction and depth and screw length are all important factors. PMID:27582950

  15. Rib fractures: comparison of associated injuries between pediatric and adult population.

    PubMed

    Kessel, Boris; Dagan, Jasmin; Swaid, Forat; Ashkenazi, Itamar; Olsha, Oded; Peleg, Kobi; Givon, Adi; Alfici, Ricardo

    2014-11-01

    Rib fractures are considered a marker of exposure to significant traumatic energy. In children, because of high elasticity of the chest wall, higher energy levels are necessary for ribs to fracture. The purpose of this study was to analyze patterns of associated injuries in children as compared with adults, all of whom presented with rib fractures. A retrospective cohort study involving blunt trauma patients with rib fractures registered in the National Trauma Registry was conducted. Of 6,995 trauma victims who were found to suffer from rib fractures, 328 were children and 6,627 were adults. Isolated rib fractures without associated injuries occurred in 19 children (5.8%) and 731 adults (11%). More adults had 4 or more fractured ribs compared with children (P < .001). Children suffered from higher rates of associated brain injuries (P = .003), hemothorax/pneumothorax (P = .006), spleen, and liver injury (P < .001). Mortality rate was 5% in both groups. The incidence of associated head, thoracic, and abdominal solid organ injuries in children was significantly higher than in adults suffering from rib fractures. In spite of a higher Injury Severity Score and incidence of associated injuries, mortality rate was similar. Mortality of rib fracture patients was mostly affected by the presence of extrathoracic injuries. Copyright © 2014 Elsevier Inc. All rights reserved.

  16. Pseudoaneurysms occurring as a result of fractures giving rise to the appearance of pseudotumors: a short series.

    PubMed

    Farquharson, Finn; Haroon, Athar; Fleet, Mustafa

    2007-01-01

    Pseudoaneurysms are focal enlargements of the vascular lumen due to partial or complete disruption of the arterial wall. These are an uncommon complication of fractures. The presence of a pseudoaneurysm adjacent to a fracture fragment can cause a pressure effect. This pressure not only impairs fracture healing but sometimes can erode the adjacent bone, producing the appearance of a pseudotumor. We present two such cases and discuss the management of these patients.

  17. Relative Dating Via Fractures

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site]

    This VIS image of the eastern part of the Tharsis region illustrates how fractures can be used in relative dating of a surface. The fractured materials on the right side of the image are embayed by younger volcanic flows originating to the west of the image. Note how the younger flows cover the ends of the fractures, and are not at all fractured themselves.

    Image information: VIS instrument. Latitude 43.2, Longitude 269.4 East (90.6 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  18. Roothaan’s approach to solve the Hartree-Fock equations for atoms confined by soft walls: Basis set with correct asymptotic behavior

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

    Rodriguez-Bautista, Mariano; Díaz-García, Cecilia; Navarrete-López, Alejandra M.

    2015-07-21

    In this report, we use a new basis set for Hartree-Fock calculations related to many-electron atoms confined by soft walls. One- and two-electron integrals were programmed in a code based in parallel programming techniques. The results obtained with this proposal for hydrogen and helium atoms were contrasted with other proposals to study just one and two electron confined atoms, where we have reproduced or improved the results previously reported. Usually, an atom enclosed by hard walls has been used as a model to study confinement effects on orbital energies, the main conclusion reached by this model is that orbital energiesmore » always go up when the confinement radius is reduced. However, such an observation is not necessarily valid for atoms confined by penetrable walls. The main reason behind this result is that for atoms with large polarizability, like beryllium or potassium, external orbitals are delocalized when the confinement is imposed and consequently, the internal orbitals behave as if they were in an ionized atom. Naturally, the shell structure of these atoms is modified drastically when they are confined. The delocalization was an argument proposed for atoms confined by hard walls, but it was never verified. In this work, the confinement imposed by soft walls allows to analyze the delocalization concept in many-electron atoms.« less

  19. Flow and fracturing of viscoelastic media under diffusion-driven bubble growth: An analogue experiment for eruptive volcanic conduits

    NASA Astrophysics Data System (ADS)

    Taddeucci, J.; Spieler, O.; Ichihara, M.; Dingwell, D. B.; Scarlato, P.

    2006-03-01

    To visualize the behavior of erupting magma in volcanic conduits, we performed shock tube experiments on the ductile-brittle response of a viscoelastic medium to diffusion-driven bubble expansion. A sample of shear-thinning magma analogue is saturated by gas Ar under high pressure. On rapid decompression, Ar supersaturation causes bubbles to nucleate, grow, and coalesce in the sample, forcing it to expand, flow, and fracture. Experimental variables include saturation pressure and duration, and shape and lubrication of the flow path. Bubble growth in the experiments controls both flow and fracturing, and is consistent with physical models of magma vesiculation. Two types of fractures are observed: i) sharp fractures along the uppermost rim of the sample, and ii) fractures pervasively diffused throughout the sample. Rim fractures open when shear stress accumulates and strain rate is highest at the margin of the flow (a process already inferred from observations and models to occur in magma). Pervasive fractures originate when wall-friction retards expansion of the sample, causing pressure to build-up in the bubbles. When bubble pressure overcomes wall-friction and the tensile strength of the porous sample, fractures open with a range of morphologies. Both types of fracture open normally to flow direction, and both may heal as the flow proceeds. These experiments also illustrate how the development of pervasive fractures allows exsolving gas to escape from the sample before the generation of a permeable network via other processes, e.g., bubble coalescence. This is an observation that potentially impact the degassing of magma and the transition between explosive and effusive eruptions.

  20. Multidisciplinary approach to chest wall resection and reconstruction for chest wall tumors, a single center experience

    PubMed Central

    Liparulo, Valeria; Pica, Alessandra; Guarro, Giuseppe; Alfano, Carmine; Puma, Francesco

    2017-01-01

    Background Chest wall resection and reconstruction (CWRR) is quite challenging in surgery, due to evolution in techniques. Neoplasms of the chest wall, primary or secondary, have been considered inoperable for a long time. Thanks to evolving surgical techniques, reconstruction after extensive chest wall resection is possible with good functional and aesthetic results. Methods In our single-center experience, seven cases of extensive CWRR for tumors were performed with a multidisciplinary approach by both thoracic and plastic surgeons. Patients have been retrospective analyzed. Results Acceptable clinical and aesthetical results have been recorded, with a smooth post-operative course and a low rate of post-surgical complications. Two early complications and one late complication (asymptomatic bone allograft fracture on the site of the bar implant) were recorded. Neither postoperative deaths nor local recurrences were registered after a median follow-up period of 13 months. Conclusions Surgical planning is most effective when it is tailored to the patient. Specifically, in the treatment of selected chest wall tumors, the multidisciplinary approach is considered mandatory when an extensive demolition is required. Indeed, here, the radical wide en-bloc resection can lead to good results provided that the extent of resection is not influenced by any anticipated problem in reconstruction. PMID:29312715

  1. Dzyaloshinskii-Moriya interaction in the presence of Rashba and Dresselhaus spin-orbit coupling

    NASA Astrophysics Data System (ADS)

    Valizadeh, Mohammad M.; Satpathy, S.

    2018-03-01

    Chiral order in magnetic structures is currently an area of considerable interest and leads to skyrmion structures and domain walls with certain chirality. The chiral structure originates from the Dzyaloshinskii-Moriya interaction caused by broken inversion symmetry and the spin-orbit interaction. In addition to the Rashba or Dresselhaus interactions, there may also exist substantial spin polarization in magnetic thin films. Here, we study the exchange interaction between two localized magnetic moments in the spin-polarized electron gas with both Rashba and Dresselhaus spin-orbit interaction present. Analytical expressions are found in certain limits in addition to what is known in the literature. The stability of the Bloch and Néel domain walls in magnetic thin films is discussed in light of our results.

  2. Orbiter LH2 Feedline Flowliner Cracking Problem. Version 1.0

    NASA Technical Reports Server (NTRS)

    Harris, Charles E.; Cragg, Clinton H.; Raju, Ivatury S.; Elliot, Kenny B.; Madaras, Eric I.; Piascik, Robert S.; Halford, Gary R.; Bonacuse, Peter J.; Sutliff, Daniel L.; Bakhle, Milind A.

    2005-01-01

    In May of 2002, three cracks were found in the downstream flowliner at the gimbal joint in the LH2 feedline at the interface with the Low Pressure Fuel Turbopump (LPFP) of Space Shuttle Main Engine (SSME) #1 of Orbiter OV-104. Subsequent inspections of the feedline flowliners in the other orbiters revealed the existence of 8 additional cracks. No cracks were found in the LO2 feedline flowliners. A solution to the cracking problem was developed and implemented on all orbiters. The solution included weld repair of all detectable cracks and the polishing of all slot edges to remove manufacturing discrepancies that could initiate new cracks. Using the results of a fracture mechanics analysis with a scatter factor of 4 on the predicted fatigue life, the orbiters were cleared for return to flight with a one-flight rationale requiring inspections after each flight. OV-104 flew mission STS-112 and OV-105 flew mission STS-113. The post-flight inspections did not find any cracks in the repaired flowliners. At the request of the Orbiter Program, the NESC conducted an assessment of the Orbiter LH2 Feedline Flowliner cracking problem with a team of subject matter experts from throughout NASA.

  3. Floor-Fractured Craters on Ceres and Implications for Internal Composition and Processes

    NASA Astrophysics Data System (ADS)

    Buczkowski, D.; Schenk, P.; Scully, J. E. C.; Park, R. S.; Preusker, F.; Raymond, C. A.; Russell, C. T.

    2016-12-01

    Several of the impact craters on Ceres have patterns of fractures on their floors. These fractures appear similar to those found within a class of lunar craters referred to as Floor-Fractured Craters (FFCs) [1]. Lunar FFCs are characterized by anomalously shallow floors cut by radial, concentric, and/or polygonal fractures, and have been classified into crater classes, Types 1 through 6, based on their morphometric properties [1,2]. Models for their formation have included both floor uplift due to magmatic intrusion below the crater or floor shallowing due to viscous relaxation. However, the observation that the depth versus diameter (d/D) relationship of the FFCs is distinctly shallower than the same association for other lunar craters supports the hypotheses that the floor fractures form due to shallow magmatic intrusion under the crater [2]. We have cataloged the Ceres FFCs according to the classification scheme designed for the Moon. Large (>50 km) Ceres FFCs are most consistent with Type 1 lunar FFCs, having deep floors, central peaks, wall terraces, and radial and/or concentric fractures. Smaller craters on Ceres are more consistent with Type 4 lunar FFCs, having less-pronounced floor fractures and v-shaped moats separating the wall scarp from the crater interior. An analysis of the d/D ratio for Ceres craters shows that, like lunar FFCs, the Ceres FFCs are anomalously shallow. This suggests that the fractures on the floor of Ceres FFCs may be due the intrusion of a low-density material below the craters that is uplifting their floors. While on the Moon the intrusive material is hypothesized to be silicate magma, this is unlikely for Ceres. However, a cryovolcanic extrusive edifice has been identified on Ceres [3], suggesting that cryomagmatic intrusions could be responsible for the formation of the Ceres FFCs. References: [1] Schultz P. (1976) Moon, 15, 241-273 [2] Jozwiak L.M. et al (2015) JGR 117, doi: 10.1029/2012JE004134 [3] Ruesch O. et al (2016

  4. Hydraulic fracture development in granite during cyclic injection

    NASA Astrophysics Data System (ADS)

    Diaz, M.; Jung, S. G.; Nam, Y. J.; Yeom, S.; Zhuang, L.; Kim, K. Y.

    2017-12-01

    The concept of fatigue hydraulic fracturing was introduced by Zang et al. (2013) as an alternative stimulation scheme to mitigate seismicity during hydraulic stimulation. In situ experiments in hard rock, and laboratory tests in granite have shown a decrease in breakdown pressure during cyclic injection. However, little work has been done in relation to the study of fracture evolution with increasing number of injection cycles. This study uses cylindrical granite specimens to observe induced fractures under continuous injection and fracture development during cyclic injection, aided by X-ray CT technology and AE monitoring. The rock specimens have 30 mm in diameter, 48 mm in height, and a 5 mm diameter central borehole drilled along its axis. Each specimen was axially loaded with 10 MPa, and without confining pressure. The first specimen was continuously injected with water at a rate of 50 mm3/s. For the second specimen, the same injection rate was used, but it was stopped multiple times when the pressure reached a value of 4 MPa in order to create cycles. The time during each injection peak was 2 min. The results show how induced fractures are likely to initiate at the borehole wall and between grain mineral boundaries. Also, the fractures increase true length and height with increasing number of cycles, and mineral distribution affected fracture orientation during its development. These observations could shed light into the physics involved behind this process

  5. Clostridium septicum gas gangrene in the orbit: a case report.

    PubMed

    Fejes, I; Dégi, R; Végh, M

    2013-02-01

    Our report presents a case of Clostridium septicum gas gangrene in an unusual, orbital localization. The predisposing factors are typical: colon tumour and lymphatic malignancy. Most probably bacteria from the intestinal flora entered the bloodstream through the compromised intestinal wall and settled in the orbit resulting in the development of an abscess containing gas. At the site of the gas gangrene, an indolent B cell lymphoma was present. After surgery and antibiotic treatment, the patient healed from the C. septicum infection; but subsequently died as a consequence of the tumour.

  6. Coupled transport, mixing and biogeochemical reactions in fractured media: experimental observations and modelling at the Ploemeur fractured rock observatory

    NASA Astrophysics Data System (ADS)

    Le Borgne, T.; Bochet, O.; Klepikova, M.; Kang, P. K.; Shakas, A.; Aquilina, L.; Dufresne, A.; Linde, N.; Dentz, M.; Bour, O.

    2016-12-01

    Transport processes in fractured media and associated reactions are governed by multiscale heterogeneity ranging from fracture wall roughness at small scale to broadly distributed fracture lengths at network scale. This strong disorder induces a variety of emerging phenomena, including flow channeling, anomalous transport and heat transfer, enhanced mixing and reactive hotspot development. These processes are generally difficult to isolate and monitor in the field because of the high degree of complexity and coupling between them. We report in situ experimental observations from the Ploemeur fractured rock observatory (http://hplus.ore.fr/en/ploemeur) that provide new insights on the dynamics of transport and reaction processes in fractured media. These include dipole and push pull tracer tests that allow understanding and modelling anomalous transport processes characterized by heavy-tailed residence time distributions (Kang et al. 2015), thermal push pull tests that show the existence of highly channeled flow with a strong control on fracture matrix exchanges (Klepikova et al. 2016) and time lapse hydrogeophysical monitoring of saline tracer tests that allow quantifying the distribution of transport length scales governing dispersion processes (Shakas et al. 2016). These transport processes are then shown to induce rapid oxygen delivery and mixing at depth leading to massive biofilm development (Bochet et al., in prep.). Hence, this presentation will attempt to link these observations made at different scales to quantify and model the coupling between flow channeling, non-Fickian transport, mixing and chemical reactions in fractured media. References: Bochet et al. Biofilm blooms driven by enhanced mixing in fractured rock, in prep. Klepikova et al. 2016, Heat as a tracer for understanding transport processes in fractured media: theory and field assessment from multi-scale thermal push-pull tracer tests, Water Resour. Res. 52Shakas et al. 2016, Hydrogeophysical

  7. Scale Effects in the Flow of a Shear-Thinning Fluid in Geological Fractures

    NASA Astrophysics Data System (ADS)

    Meheust, Y.; Roques, C.; Le Borgne, T.; Selker, J. S.

    2017-12-01

    Subsurface flow processes involving non-Newtonian fluids play a major role in many engineering applications, from in-situ remediation to enhanced oil recovery. The fluids of interest in such applications (f.e., polymers in remediation) often present shear-thinning properties, i.e., their viscosity decreases as a function of the local shear rate. We investigate how fracture wall roughness impacts the flow of a shear-thinning fluid. Numerical simulations of flow in 3D geological fractures are carried out by solving a modified Navier-Stokes equation incorporating the Carreau viscous-shear model. The numerical fractures consist of two isotropic self-affine surfaces which are correlated with each other above a characteristic scale (thecorrelation length of Méheust et al. PAGEOPH 2003). Perfect plastic closing is assumed when the surfaces are in contact. The statistical parameters describing a fracture are the standard deviation of the wall roughness, the mean aperture, the correlation length, and the fracture length, the Hurst exponent being fixed (equal to 0.8). The objective is to investigate how varying the correlation length impacts the flow behavior, for different degrees of closure, and how this behavior diverges from what is known for Newtonian fluids. The results from the 3D simulations are also compared to 2D simulations based on the lubrication theory, which we have developed as an extension of the Reynolds equation for Newtonian fluids. These 2D simulations run orders of magnitude faster, which allows considering a significant statistics of fractures of identical statistical parameters, and therefore draw general conclusions despite the large stochasticity of the media. We also discuss the implications of our results for solute transport by such flows. References:Méheust, Y., & Schmittbuhl, J. (2003). Scale effects related to flow in rough fractures. Pure and Applied Geophysics, 160(5-6), 1023-1050.

  8. Sphenoid Sinus and Sphenoid Bone Fractures in Patients with Craniomaxillofacial Trauma

    PubMed Central

    Cantini Ardila, Jorge Ernesto; Mendoza, Miguel Ángel Rivera; Ortega, Viviana Gómez

    2013-01-01

    Background and Purpose Sphenoid bone fractures and sphenoid sinus fractures have a high morbidity due to its association with high-energy trauma. The purpose of this study is to describe individuals with traumatic injuries from different mechanisms and attempt to determine if there is any relationship between various isolated or combined fractures of facial skeleton and sphenoid bone and sphenoid sinus fractures. Methods We retrospectively studied hospital charts of all patients who reported to the trauma center at Hospital de San José with facial fractures from December 2009 to August 2011. All patients were evaluated by computed tomography scan and classified into low-, medium-, and high-energy trauma fractures, according to the classification described by Manson. Design This is a retrospective descriptive study. Results The study data were collected as part of retrospective analysis. A total of 250 patients reported to the trauma center of the study hospital with facial trauma. Thirty-eight patients were excluded. A total of 212 patients had facial fractures; 33 had a combination of sphenoid sinus and sphenoid bone fractures, and facial fractures were identified within this group (15.5%). Gender predilection was seen to favor males (77.3%) more than females (22.7%). The mean age of the patients was 37 years. Orbital fractures (78.8%) and maxillary fractures (57.5%) were found more commonly associated with sphenoid sinus and sphenoid bone fractures. Conclusions High-energy trauma is more frequently associated with sphenoid fractures when compared with medium- and low-energy trauma. There is a correlation between facial fractures and sphenoid sinus and sphenoid bone fractures. A more exhaustive multicentric case-control study with a larger sample and additional parameters will be essential to reach definite conclusions regarding the spectrum of fractures of the sphenoid bone associated with facial fractures. PMID:24436756

  9. Impact of Injury Mechanisms on Patterns and Management of Facial Fractures.

    PubMed

    Greathouse, S Travis; Adkinson, Joshua M; Garza, Ramon; Gilstrap, Jarom; Miller, Nathan F; Eid, Sherrine M; Murphy, Robert X

    2015-07-01

    Mechanisms causing facial fractures have evolved over time and may be predictive of the types of injuries sustained. The objective of this study is to examine the impact of mechanisms of injury on the type and management of facial fractures at our Level 1 Trauma Center. The authors performed an Institutional Review Board-approved review of our network's trauma registry from 2006 to 2010, documenting age, sex, mechanism, Injury Severity Score, Glasgow Coma Scale, facial fracture patterns (nasal, maxillary/malar, orbital, mandible), and reconstructions. Mechanism rates were compared using a Pearson χ2 test. The database identified 23,318 patients, including 1686 patients with facial fractures and a subset of 1505 patients sustaining 2094 fractures by motor vehicle collision (MVC), fall, or assault. Nasal fractures were the most common injuries sustained by all mechanisms. MVCs were most likely to cause nasal and malar/maxillary fractures (P < 0.01). Falls were the least likely and assaults the most likely to cause mandible fractures (P < 0.001), the most common injury leading to surgical intervention (P < 0.001). Although not statistically significant, fractures sustained in MVCs were the most likely overall to undergo surgical intervention. Age, number of fractures, and alcohol level were statistically significant variables associated with operative management. Age and number of fractures sustained were associated with operative intervention. Although there is a statistically significant correlation between mechanism of injury and type of facial fracture sustained, none of the mechanisms evaluated herein are statistically associated with surgical intervention. Clinical Question/Level of Evidence: Therapeutic, III.

  10. Age and sex-related differences in 431 pediatric facial fractures at a level 1 trauma center.

    PubMed

    Hoppe, Ian C; Kordahi, Anthony M; Paik, Angie M; Lee, Edward S; Granick, Mark S

    2014-10-01

    Age and sex-related changes in the pattern of fractures and concomitant injuries observed in this patient population is helpful in understanding craniofacial development and the treatment of these unique injuries. The goal of this study was to examine all facial fractures occurring in a child and adolescent population (age 18 or less) at a trauma center to determine any age or sex-related variability amongst fracture patterns and concomitant injuries. All facial fractures occurring at a trauma center were collected over a 12-year period based on International Classification of Disease, rev. 9 codes. This was delimited to include only those patients 18 years of age or younger. Age, sex, mechanism, and fracture types were collected and analyzed. During this time period, there were 3147 patients with facial fractures treated at our institution, 353 of which were in children and adolescent patients. Upon further review 68 patients were excluded due to insufficient data for analysis, leaving 285 patients for review, with a total of 431 fractures. The most common etiology of injury was assault for males and motor vehicle accidents (MVA) for females. The most common fracture was of the mandible in males and of the orbit in females. The most common etiology in younger age groups includes falls and pedestrian struck. Older age groups exhibit a higher incidence of assault-related injuries. Younger age groups showed a propensity for orbital fractures as opposed to older age groups where mandibular fractures predominated. Intracranial hemorrhage was the most common concomitant injury across most age groups. The differences noted in etiology of injury, fracture patterns, and concomitant injuries between sexes and different age groups likely reflects the differing activities that each group engages in predominantly. In addition the growing facial skeleton offers varying degrees of protection to the cranial contents as force-absorbing mechanisms develop. Copyright © 2014

  11. Fracture hydromechanical response measured by fiber optic distributed acoustic sensing at milliHertz frequencies

    NASA Astrophysics Data System (ADS)

    Becker, M. W.; Ciervo, C.; Cole, M.; Coleman, T.; Mondanos, M.

    2017-07-01

    A new method of measuring dynamic strain in boreholes was used to record fracture displacement in response to head oscillation. Fiber optic distributed acoustic sensing (DAS) was used to measure strain at mHz frequencies, rather than the Hz to kHz frequencies typical for seismic and acoustic monitoring. Fiber optic cable was mechanically coupled to the wall of a borehole drilled into fractured crystalline bedrock. Oscillating hydraulic signals were applied at a companion borehole 30 m away. The DAS instrument measured fracture displacement at frequencies of less than 1 mHz and amplitudes of less than 1 nm, in response to fluid pressure changes of less 20 Pa (2 mm H2O). Displacement was linearly related to the log of effective stress, a relationship typically explained by the effect of self-affine fracture roughness on fracture closure. These results imply that fracture roughness affects closure even when displacement is a million times smaller than the fracture aperture.

  12. The evolution of fracture surface roughness and its dependence on slip

    NASA Astrophysics Data System (ADS)

    Wells, Olivia L.

    Under effective compression, impingement of opposing rough surfaces of a fracture can force the walls of the fracture apart during slip. Therefore, a fracture's surface roughness exerts a primary control on the amount of dilation that can be sustained on a fracture since the opposing surfaces need to remain in contact. Previous work has attempted to characterize fracture surface roughness through topographic profiles and power spectral density analysis, but these metrics describing the geometry of a fracture's surface are often non-unique when used independently. However, when combined these metrics are affective at characterizing fracture surface roughness, as well as the mechanisms affecting changes in roughness with increasing slip, and therefore changes in dilation. These mechanisms include the influence of primary grains and pores on initial fracture roughness, the effect of linkage on locally increasing roughness, and asperity destruction that limits the heights of asperities and forms gouge. This analysis reveals four essential stages of dilation during the lifecycle of a natural fracture, whereas previous slip-dilation models do not adequately address the evolution of fracture surface roughness: (1) initial slip companied by small dilation is mediated by roughness controlled by the primary grain and pore dimensions; (2) rapid dilation during and immediately following fracture growth by linkage of formerly isolated fractures; (3) wear of the fracture surface and gouge formation that minimizes dilation; and (4) between slip events cementation that modifies the mineral constituents in the fracture. By identifying these fundamental mechanisms that influence fracture surface roughness, this new conceptual model relating dilation to slip has specific applications to Enhanced Geothermal Systems (EGS), which attempt to produce long-lived dilation in natural fractures by inducing slip.

  13. Stabilization of multiple rib fractures in a canine model.

    PubMed

    Huang, Ke-Nan; Xu, Zhi-Fei; Sun, Ju-Xian; Ding, Xin-Yu; Wu, Bin; Li, Wei; Qin, Xiong; Tang, Hua

    2014-12-01

    Operative stabilization is frequently used in the clinical treatment of multiple rib fractures (MRF); however, no ideal material exists for use in this fixation. This study investigates a newly developed biodegradable plate system for the stabilization of MRF. Silk fiber-reinforced polycaprolactone (SF/PCL) plates were developed for rib fracture stabilization and studied using a canine flail chest model. Adult mongrel dogs were divided into three groups: one group received the SF/PCL plates, one group received standard clinical steel plates, and the final group did not undergo operative fracture stabilization (n = 6 for each group). Radiographic, mechanical, and histologic examination was performed to evaluate the effectiveness of the biodegradable material for the stabilization of the rib fractures. No nonunion and no infections were found when using SF-PCL plates. The fracture sites collapsed in the untreated control group, leading to obvious chest wall deformity not encountered in the two groups that underwent operative stabilization. Our experimental study shows that the SF/PCL plate has the biocompatibility and mechanical strength suitable for fixation of MRF and is potentially ideal for the treatment of these injuries. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Lunar Floor-Fractured Craters: Classification, Distribution and Implications for Magmatism and Shallow Crustal Structure

    NASA Technical Reports Server (NTRS)

    Jozwiak, L. M.; Head, J. W.; Neumann, G. A.; Zuber, M. T.; Smith, D. E.

    2012-01-01

    Floor-fractured craters (FFCs) are a class of lunar craters defined by their distinctly shallow, often plate-like floors, and combinations of radial, con-centric, and polygonal floor-fractures; a variety of other interior features are often observed, such as moats, ridges, small dark-haloed pits, and patches of mare material. They were first classified by Schultz [1] , who recognized eight overall types of floor-fractured crater. These eight subtypes have widely differing appearances, a factor that could provide insight into formation mechanisms (different manifestations of the same mechanism, or indicators of varying formation mechanisms). Two formation mechanisms for FFCs were initially proposed: 1) magmatic intrusion [1], in which magma rising toward the surface in dikes encountered low-density breccia lenses beneath crater floors and spread laterally to form sills, raising and fracturing the crater floor. 2) viscous relaxation [2], in which the properties of the crust permitted viscous flow in the vicinity of the crater, causing long-wavelength relaxation of the topography and uplift and fracturing of the crater floor. Critical to distinguishing between these two end-member hypotheses and identifying others is a quantitative assessment of the topography of FFCs and knowledge of their regional and local settings. The purpose of this study is to use newly available Lunar Reconnaissance Orbiter (LRO) Lunar Orbiter Laser Altimeter (LOLA) altimeter and Lunar Reconnaissance Orbiter Camera (LROC) image data to provide an updated global catalog of the locations, classes, morphometric and morphologic characteristics of all lunar floor-fractured craters. We use the excellent 8-class system initially described in Schultz [1] as a starting point for classification and the enhanced LOLA/LROC data sets to examine and categorize all FFCs; we found evidence for a new FFC class, discernably different from the previously existing types. Our approach, and the global

  15. Low-frequency fluid waves in fractures and pipes

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

    Korneev, Valeri

    2010-09-01

    Low-frequency analytical solutions have been obtained for phase velocities of symmetrical fluid waves within both an infinite fracture and a pipe filled with a viscous fluid. Three different fluid wave regimes can exist in such objects, depending on the various combinations of parameters, such as fluid density, fluid viscosity, walls shear modulus, channel thickness, and frequency. Equations for velocities of all these regimes have explicit forms and are verified by comparisons with the exact solutions. The dominant role of fractures in rock permeability at field scales and the strong amplitude and frequency effects of Stoneley guided waves suggest the importancemore » of including these wave effects into poroelastic theories.« less

  16. Radionuclide Transport in Fracture-Granite Interface Zones

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

    Hu, Q; Mori, A

    In situ radionuclide migration experiments, followed by excavation and sample characterization, were conducted in a water-conducting shear zone at the Grimsel Test Site (GTS) in Switzerland to study diffusion paths of radionuclides in fractured granite. In this work, we employed a micro-scale mapping technique that interfaces laser ablation sampling with inductively coupled plasma-mass spectrometry (LA/ICP-MS) to measure the fine-scale (micron-range) distribution of actinides ({sup 234}U, {sup 235}U, and {sup 237}Np) in the fracture-granite interface zones. Long-lived {sup 234}U, {sup 235}U, and {sup 237}Np were detected in flow channels, as well as in the adjacent rock matrix, using the sensitive, feature-basedmore » mapping of the LA/ICP-MS technique. The injected sorbing actinides are mainly located within the advective flowing fractures and the immediately adjacent regions. The water-conducting fracture studied in this work is bounded on one side by mylonite and the other by granitic matrix regions. These actinides did not penetrate into the mylonite side as much as the relatively higher-porosity granite matrix, most likely due to the low porosity, hydraulic conductivity, and diffusivity of the fracture wall (a thickness of about 0.4 mm separates the mylonite region from the fracture) and the mylonite region itself. Overall, the maximum penetration depth detected with this technique for the more diffusive {sup 237}Np over the field experimental time scale of about 60 days was about 10 mm in the granitic matrix, illustrating the importance of matrix diffusion in retarding radionuclide transport from the advective fractures. Laboratory tests and numerical modeling of radionuclide diffusion into granitic matrix was conducted to complement and help interpret the field results. Measured apparent diffusivity of multiple tracers in granite provided consistent predictions for radionuclide transport in the fractured granitic rock.« less

  17. Resonant tunneling across a ferroelectric domain wall

    NASA Astrophysics Data System (ADS)

    Li, M.; Tao, L. L.; Velev, J. P.; Tsymbal, E. Y.

    2018-04-01

    Motivated by recent experimental observations, we explore electron transport properties of a ferroelectric tunnel junction (FTJ) with an embedded head-to-head ferroelectric domain wall, using first-principles density-functional theory calculations. We consider a FTJ with L a0.5S r0.5Mn O3 electrodes separated by a BaTi O3 barrier layer and show that an in-plane charged domain wall in the ferroelectric BaTi O3 can be induced by polar interfaces. The resulting V -shaped electrostatic potential profile across the BaTi O3 layer creates a quantum well and leads to the formation of a two-dimensional electron gas, which stabilizes the domain wall. The confined electronic states in the barrier are responsible for resonant tunneling as is evident from our quantum-transport calculations. We find that the resonant tunneling is an orbital selective process, which leads to sharp spikes in the momentum- and energy-resolved transmission spectra. Our results indicate that domain walls embedded in FTJs can be used to control the electron transport.

  18. Lunar Return Reentry Thermal Analysis of a Generic Crew Exploration Vehicle Wall Structures

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Tran, Van T.; Bowles, Jeff

    2007-01-01

    Thermostructural analysis was performed on generic crew exploration vehicle (GCEV) heat shielded wall structures subjected to reentry heating rates based on five potential lunar return reentry trajectories. The GCEV windward outer wall is fabricated with a graphite/epoxy composite honeycomb sandwich panel and the inner wall with an aluminum honeycomb sandwich panel. The outer wall is protected with an ablative Avcoat-5026-39H/CG thermal protection system (TPS). A virtual ablation method (a graphical approximation) developed earlier was further extended, and was used to estimate the ablation periods, ablation heat loads, and the TPS recession layer depths. It was found that up to 83 95 percent of the total reentry heat load was dissipated in the TPS ablation process, leaving a small amount (3-15 percent) of the remaining total reentry heat load to heat the virgin TPS and maintain the TPS surface at the ablation temperature, 1,200 F. The GCEV stagnation point TPS recession layer depths were estimated to be in the range of 0.280-0.910 in, and the allowable minimum stagnation point TPS thicknesses that could maintain the substructural composite sandwich wall at the limit temperature of 300 F were found to be in the range of 0.767-1.538 in. Based on results from the present analyses, the lunar return abort ballistic reentry was found to be quite attractive because it required less TPS weight than the lunar return direct, the lunar return skipping, or the low Earth orbit guided reentry, and only 11.6 percent more TPS weight than the low Earth orbit ballistic reentry that will encounter a considerable weight penalty to obtain the Earth orbit. The analysis also showed that the TPS weight required for the lunar return skipping reentry was much more than the TPS weight necessary for any of the other reentry trajectories considered.

  19. Spacecraft wall design for increased protection against penetration by space debris impacts

    NASA Technical Reports Server (NTRS)

    Schonberg, William P.; Tullos, Randy J.

    1990-01-01

    All orbiting spacecraft are susceptible to impacts by meteoroids and pieces of orbital space debris. These impacts occur at extremely high speeds and can damage flight-critical systems, which can in turn lead to catastrophic failure of the spacecraft. The design of a spacecraft for a long-duration mission into the meteoroid and space debris environment must include adequate protection against perforation of pressurized components by such impacts. This paper presents the results of an investigation into the perforation resistance of dual-wall structural systems fabricated with monolithic bumper plates and with corrugated bumper plates of equal weight. A comparative analysis of the impact damage in dual-wall systems with corrugated bumper specimens and that in dual-wall specimens with monolithic bumpers of similar weight is performed to determine the advantages and disadvantages of employing corrugated bumpers in structural wall systems for long-duration spacecraft. The analysis indicates that a significant increase in perforation protection can be achieved if a monolithic bumper is replaced by a corrugated bumper of equal weight. The parameters of the corrugations in the corrugated bumper plates are optimized in a manner that minimizes the potential for the creation of ricochet debris in the event of an oblique hypervelocity impact. Several design examples using the optimization scheme are presented and discussed.

  20. Characteristics of the Shuttle Orbiter Leeside Flow During A Reentry Condition

    NASA Technical Reports Server (NTRS)

    Kleb, William L.; Weilmuenster, K. James

    1992-01-01

    A study of the leeside flow characteristics of the Shuttle Orbiter is presented for a reentry flight condition. The flow is computed using a point-implicit, finite-volume scheme known as the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA). LAURA is a second-order accurate, laminar Navier-Stokes solver, incorporating finite-rate chemistry with a radiative equilibrium wall temperature distribution and finite-rate wall catalysis. The resulting computational solution is analyzed in terms of salient flow features and the surface quantities are compared with flight data.

  1. Effect of multi-layer thermal insulation thickness and location on the hypervelocity impact response of dual-wall structures

    NASA Astrophysics Data System (ADS)

    Schonberg, William P.

    Traditional perforation-resistant wall design for long-duration spacecraft consists of a "bumper" that is placed a small distance away from the main "pressure wall" of a spacecraft compartment or module. This concept has been studied extensively as a means of reducing the perforation threat of hypervelocity projectiles such as meteoroids and orbital debris. If a dual-wall system is employed on an earth-orbiting spacecraft, then a blanket of multi-layer insulation (MLI) will typically be included within the dual-wall system for thermal protection purposes. This paper presents the results of an experimental study in which aluminum dual-wall structures were tested under a variety of high-speed impact conditions to study the effect of MLI thickness and location on perforation resistance. The results presented consist of test-by-test comparisons of the damage sustained by similar dual-wall systems with blanket MLI of various thicknesses and at various locations within the dual-wall systems under similar impact loading conditions. The analyses performed revealed that the placement of the MLI had a significant effect on the ballistic limit of the dual-wall structures considered while reducing the thickness of the MLI by as much as 1/3 did not.

  2. Role of multiple cusps in tooth fracture.

    PubMed

    Barani, Amir; Bush, Mark B; Lawn, Brian R

    2014-07-01

    The role of multiple cusps in the biomechanics of human molar tooth fracture is analysed. A model with four cusps at the bite surface replaces the single dome structure used in previous simulations. Extended finite element modelling, with provision to embed longitudinal cracks into the enamel walls, enables full analysis of crack propagation from initial extension to final failure. The cracks propagate longitudinally around the enamel side walls from starter cracks placed either at the top surface (radial cracks) or from the tooth base (margin cracks). A feature of the crack evolution is its stability, meaning that extension occurs steadily with increasing applied force. Predictions from the model are validated by comparison with experimental data from earlier publications, in which crack development was followed in situ during occlusal loading of extracted human molars. The results show substantial increase in critical forces to produce longitudinal fractures with number of cuspal contacts, indicating a capacity for an individual tooth to spread the load during mastication. It is argued that explicit critical force equations derived in previous studies remain valid, at the least as a means for comparing the capacity for teeth of different dimensions to sustain high bite forces. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. [Use and versatility of titanium for the reconstruction of the thoracic wall].

    PubMed

    Córcoles Padilla, Juan Manuel; Bolufer Nadal, Sergio; Kurowski, Krzysztof; Gálvez Muñoz, Carlos; Rodriguez Paniagua, José Manuel

    2014-02-01

    Chest wall deformities/defects and chest wall resections, as well as complex rib fractures require reconstruction with various prosthetic materials to ensure the basic functions of the chest wall. Titanium provides many features that make it an ideal material for this surgery. The aim is to present our initial results with this material in several diseases. From 2008 to 2012, 14 patients were operated on and titanium was used for reconstruction of the chest wall. A total of 7 patients had chest wall tumors, 2 with sternal resection, 4 patients with chest wall deformities/defects and 3 patients with severe rib injury due to traffic accident. The reconstruction was successful in all cases, with early extubation without detecting problems in the functionality of the chest wall at a respiratory level. Patients with chest wall tumors including sternal resections were extubated in the operating room as well as the chest wall deformities. Chest trauma cases were extubated within 24h from internal rib fixation. There were no complications related to the material used and the method of implementation. Titanium is an ideal material for reconstruction of the chest wall in several clinical situations allowing for great versatility and adaptability in different chest wall reconstructions. Copyright © 2013 AEC. Published by Elsevier Espana. All rights reserved.

  4. Piezosurgery in Modified Pterional Orbital Decompression Surgery in Graves Disease.

    PubMed

    Grauvogel, Juergen; Scheiwe, Christian; Masalha, Waseem; Jarc, Nadja; Grauvogel, Tanja; Beringer, Andreas

    2017-10-01

    Piezosurgery uses microvibrations to selectively cut bone, preserving the adjacent soft tissue. The present study evaluated the use of piezosurgery for bone removal in orbital decompression surgery in Graves disease via a modified pterional approach. A piezosurgical device (Piezosurgery medical) was used in 14 patients (20 orbits) with Graves disease who underwent orbital decompression surgery in additional to drills and rongeurs for bone removal of the lateral orbital wall and orbital roof. The practicability, benefits, and drawbacks of this technique in orbital decompression surgery were recorded. Piezosurgery was evaluated with respect to safety, preciseness of bone cutting, and preservation of the adjacent dura and periorbita. Preoperative and postoperative clinical outcome data were assessed. The orbital decompression surgery was successful in all 20 orbits, with good clinical outcomes and no postoperative complications. Piezosurgery proved to be a safe tool, allowing selective bone cutting with no damage to the surrounding soft tissue structures. However, there were disadvantages concerning the intraoperative handling in the narrow space and the efficiency of bone removal was limited in the orbital decompression surgery compared with drills. Piezosurgery proved to be a useful tool in bone removal for orbital decompression in Graves disease. It is safe and easy to perform, without any danger of damage to adjacent tissue because of its selective bone-cutting properties. Nonetheless, further development of the device is necessary to overcome the disadvantages in intraoperative handling and the reduced bone removal rate. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Effect of isolated fractures on accelerated flow in unsaturated porous rock

    USGS Publications Warehouse

    Su, Grace W.; Nimmo, John R.; Dragila, Maria I.

    2003-01-01

    Fractures that begin and end in the unsaturated zone, or isolated fractures, have been ignored in previous studies because they were generally assumed to behave as capillary barriers and remain nonconductive. We conducted a series of experiments using Berea sandstone samples to examine the physical mechanisms controlling flow in a rock containing a single isolated fracture. The input fluxes and fracture orientation were varied in these experiments. Visualization experiments using dyed water in a thin vertical slab of rock were conducted to identify flow mechanisms occurring due to the presence of the isolated fracture. Two mechanisms occurred: (1) localized flow through the rock matrix in the vicinity of the isolated fracture and (2) pooling of water at the bottom of the fracture, indicating the occurrence of film flow along the isolated fracture wall. These mechanisms were observed at fracture angles of 20 and 60 degrees from the horizontal, but not at 90 degrees. Pooling along the bottom of the fracture was observed over a wider range of input fluxes for low‐angled isolated fractures compared to high‐angled ones. Measurements of matrix water pressures in the samples with the 20 and 60 degree fractures also demonstrated that preferential flow occurred through the matrix in the fracture vicinity, where higher pressures occurred in the regions where faster flow was observed in the visualization experiments. The pooling length at the terminus of a 20 degree isolated fracture was measured as a function of input flux. Calculations of the film flow rate along the fracture were made using these measurements and indicated that up to 22% of the flow occurred as film flow. These experiments, apparently the first to consider isolated fractures, demonstrate that such features can accelerate flow through the unsaturated zone and should be considered when developing conceptual models.

  6. Localizing Fracture Hydromechanical Response using Fiber Optic Distributed Acoustic Sensing in a Fractured Bedock Aquifer

    NASA Astrophysics Data System (ADS)

    Chevrot, S.; Wang, Y.; Monteiller, V.; Komatitsch, D.; Martin, R.

    2016-12-01

    Measuring fracture mechanical behavior in response to changes in fluid pressure is critical for understanding flow through petroleum reservoirs, predicting hydrothermal responses in geothermal fields, and monitoring geologic carbon sequestration injection. Distributed acoustic sensing (DAS) is new, but commercially available fiber optic technology that offers a novel approach to characterize fractured bedrock systems. DAS was originally designed to measure the amplitude, frequency, and phase of an acoustic wave, and is therefore capable of detecting strains at exceedingly small scales. Though normally used to measure frequencies in the Hz to kHz range, we adapted DAS to measure fracture displacements in response to periodic hydraulic pulses in the mHz frequency range. A field experiment was conducted in a fractured bedrock aquifer to test the ability of DAS to measure fracture mechanical response to oscillatory well tests. Fiber optic cable was deployed in a well, and coupled to the borehole wall using a flexible impermeable liner designed with an air coupled transducer to measure fluid pressure at the target fracture zone. Two types of cable were tested, a loose tube and tight buffered, to determine the effects of cable construction. Both strain and pressure were measured across the known fracture zone hydraulically connected to a well 30 m away. The companion well was subjected to alternating pumping and injection with periods between 2 and 18 minutes. Raw DAS data were collected as strain rate measured every 0.25 m along the fiber with a gauge length of 10 m, at a sampling rate of 1 kHz. Strain rate was converted to strain by integrating with respect to time. DAS measured periodic strains of less than 1 nm/m in response to periodic injection and pumping at the companion well. Strain was observed by DAS only at the depth of the hydraulically connected fracture zone. Thus, the magnitude and response of the strain could be both localized with depth and measured

  7. Localizing Fracture Hydromechanical Response using Fiber Optic Distributed Acoustic Sensing in a Fractured Bedock Aquifer

    NASA Astrophysics Data System (ADS)

    Ciervo, C.; Becker, M.; Cole, M. C.; Coleman, T.; Mondanos, M.

    2017-12-01

    Measuring fracture mechanical behavior in response to changes in fluid pressure is critical for understanding flow through petroleum reservoirs, predicting hydrothermal responses in geothermal fields, and monitoring geologic carbon sequestration injection. Distributed acoustic sensing (DAS) is new, but commercially available fiber optic technology that offers a novel approach to characterize fractured bedrock systems. DAS was originally designed to measure the amplitude, frequency, and phase of an acoustic wave, and is therefore capable of detecting strains at exceedingly small scales. Though normally used to measure frequencies in the Hz to kHz range, we adapted DAS to measure fracture displacements in response to periodic hydraulic pulses in the mHz frequency range. A field experiment was conducted in a fractured bedrock aquifer to test the ability of DAS to measure fracture mechanical response to oscillatory well tests. Fiber optic cable was deployed in a well, and coupled to the borehole wall using a flexible impermeable liner designed with an air coupled transducer to measure fluid pressure at the target fracture zone. Two types of cable were tested, a loose tube and tight buffered, to determine the effects of cable construction. Both strain and pressure were measured across the known fracture zone hydraulically connected to a well 30 m away. The companion well was subjected to alternating pumping and injection with periods between 2 and 18 minutes. Raw DAS data were collected as strain rate measured every 0.25 m along the fiber with a gauge length of 10 m, at a sampling rate of 1 kHz. Strain rate was converted to strain by integrating with respect to time. DAS measured periodic strains of less than 1 nm/m in response to periodic injection and pumping at the companion well. Strain was observed by DAS only at the depth of the hydraulically connected fracture zone. Thus, the magnitude and response of the strain could be both localized with depth and measured

  8. Juvenile nasopharyngeal angiofibroma--a rare case of primary orbital development.

    PubMed

    Moschos, M; Demetra, A; Kontogeorgos, G

    1998-08-01

    To present a rare case of juvenile nasopharyngeal angiofibroma invading the ophthalmic orbit. The CT scan examination and the ultrasound tomography revealed the existence of a homogeneous solid mass causing distention and erosion of the nasal wall as well as dislocation of the ocular bulbus. The patient was operated, the mass was carefully liberated from its synechiae and it was totally excised with its capsule. A rare case of juvenile nasopharyngeal angiofibroma invading the orbit is presented. The tumor was totally excized and the patient is five years after the operation in good general health without recurrence of the tumor.

  9. Thermal Effect on Fracture Integrity in Enhanced Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Zeng, C.; Deng, W.; Wu, C.; Insall, M.

    2017-12-01

    In enhanced geothermal systems (EGS), cold fluid is injected to be heated up for electricity generation purpose, and pre-existing fractures are the major conduits for fluid transport. Due to the relative cold fluid injection, the rock-fluid temperature difference will induce thermal stress along the fracture wall. Such large thermal stress could cause the failure of self-propping asperities and therefore change the fracture integrity, which could affect the heat recovery efficiency and fluid recycling. To study the thermal effect on fracture integrity, two mechanisms pertinent to thermal stress are proposed to cause asperity contact failure: (1) the crushing between two pairing asperities leads to the failure at contact area, and (2) the thermal spalling expedites this process. Finite element modeling is utilized to investigate both failure mechanisms by idealizing the asperities as hemispheres. In the numerical analysis, we have implemented meso-scale damage model to investigate coupled failure mechanism induced by thermomechanical stress field and original overburden pressure at the vicinity of contact point. Our results have shown that both the overburden pressure and a critical temperature determine the threshold of asperity failure. Since the overburden pressure implies the depth of fractures in EGS and the critical temperature implies the distance of fractures to the injection well, our ultimate goal is to locate a region of EGS where the fracture integrity is vulnerable to such thermal effect and estimate the influences.

  10. Designing a monitoring network for contaminated ground water in fractured chalk

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

    Nativ, R.; Adar, E.M.; Becker, A.

    1999-01-01

    One of the challenges of monitoring network design in a fractured rock setting is the heterogeneity of the rocks. This paper summarizes the activities and problems associated with the monitoring of contaminated groundwater in porous, low-permeability fractured chalk in the Negev Desert, Israel. Preferential flow documented in the study area required siting the monitoring boreholes in the predominant fracture systems. Lineaments traced from aerial photographs were examined in the field to sort out the large-extension, through-going, multilayer fracture systems crossing the study area. At each proposed drilling site, these fractures were exposed below the sediment cover using trenches. Slanted boreholesmore » were drilled at a distance from the fracture systems so that each borehole would intersect the targeted fracture plane below the water table. Based on their short recovery period and contaminated ground water, these newly drilled, fracture-oriented boreholes appeared to be better connected to preferential flowpaths crossing the industrial site than the old boreholes existing on site. Other considerations concerning the drilling and logging of monitoring boreholes in a fractured media were: (1) coring provides better documentation of the vertical fracture distribution, but dry augering is less costly and enables immediate ground water sampling and the sampling of vadose rock for contaminant analysis; (2) caliper and TV camera logs appear to provide only partial information regarding the vertical fracture distribution; and (3) the information gained by deepening the monitoring boreholes and testing fractures crossing their uncased walls has to be carefully weighed against the risk of potential cross-contamination through the monitoring boreholes, which is enhanced in fractured media.« less

  11. The use of broadband microseisms for hydraulic fracture mapping

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

    Sleefe, G.E.; Warpinski, N.R.; Engler, B.P.

    When a hydrocarbon reservoir is subjected to a hydraulic fracture treatment, the cracking and slipping of the formation results in the emission of seismic energy. The objective of this study was to determine the advantages of using broadband (100 Hz to 1500 M) microseismic emissions to map a hydraulic fracture treatment. A hydraulic fracture experiment was performed in the Piceance Basin of Western Colorado to induce and record broadband microseismic events. The formation was subjected to four processes; break-down/ballout, step-rate test, KCL mini-fracture, and linear-gel mini-fracture. Broadband microseisms were successfully recorded by a novel three-component wall-locked seismic accelerometer package, placedmore » in an observation well 211 ft (64 m) offset from the treatment well. During the two hours of formation treatment, more than 1200 significant microseismic events were observed. The occurrences of the events strongly correlated with the injection bore-bole pressures during the treatments. Using both hodogram analysis and time of arrival information, estimates of the origination point of the seismic events were computed. A map of the event locations yielded a fracture orientation estimate consistent with the known orientation of the field in the formation. This paper describes the technique for acquiring and analyzing broadband microseismic events and illustrate how the new broadband approach can enhance signal detectability and event location resolution.« less

  12. Laboratory imaging of hydraulic fractures using microseismicity

    NASA Astrophysics Data System (ADS)

    Zeng, Zhengwen

    2002-09-01

    of the packer influence on HF initiation. It is numerically shown that a properly functioning packer would transfer tensile stress concentrations from the sealed ends to the borehole wall in the maximum principal stress direction. In contrast, a malfunctioning packer would induce tensile stress concentrations at the sealed ends that, in turn, induces transverse fractures. (7) Image of dynamics of the asymmetrical hydraulic fracture initiation and propagation.

  13. Impact of automobile restraint device utilization on facial fractures and fiscal implications for plastic surgeons.

    PubMed

    Adkinson, Joshua M; Murphy, Robert X

    2011-05-01

    In 2009, the National Highway Traffic Safety Administration projected that 33,963 people would die and millions would be injured in motor vehicle collisions (MVC). Multiple studies have evaluated the impact of restraint devices in MVCs. This study examines longitudinal changes in facial fractures after MVC as result of utilization of restraint devices. The Pennsylvania Trauma Systems Foundation-Pennsylvania Trauma Outcomes Study database was queried for MVCs from 1989 to 2009. Restraint device use was noted, and facial fractures were identified by International Classification of Diseases-ninth revision codes. Surgeon cost data were extrapolated. More than 15,000 patients sustained ≥1 facial fracture. Only orbital blowout fractures increased over 20 years. Patients were 2.1% less likely every year to have ≥1 facial fracture, which translated into decreased estimated surgeon charges. Increased use of protective devices by patients involved in MVCs resulted in a change in incidence of different facial fractures with reduced need for reconstructive surgery.

  14. Spin-orbit torques in magnetic bilayers

    NASA Astrophysics Data System (ADS)

    Haney, Paul

    2015-03-01

    Spintronics aims to utilize the coupling between charge transport and magnetic dynamics to develop improved and novel memory and logic devices. Future progress in spintronics may be enabled by exploiting the spin-orbit coupling present at the interface between thin film ferromagnets and heavy metals. In these systems, applying an in-plane electrical current can induce magnetic dynamics in single domain ferromagnets, or can induce rapid motion of domain wall magnetic textures. There are multiple effects responsible for these dynamics. They include spin-orbit torques and a chiral exchange interaction (the Dzyaloshinskii-Moriya interaction) in the ferromagnet. Both effects arise from the combination of ferromagnetism and spin-orbit coupling present at the interface. There is additionally a torque from the spin current flux impinging on the ferromagnet, arising from the spin hall effect in the heavy metal. Using a combination of approaches, from drift-diffusion to Boltzmann transport to first principles methods, we explore the relative contributions to the dynamics from these different effects. We additionally propose that the transverse spin current is locally enhanced over its bulk value in the vicinity of an interface which is oriented normal to the charge current direction.

  15. Pleomorphic adenoma of a deep orbital ectopic lacrimal gland.

    PubMed

    Misra, Somen; Bhandari, Akshay; Misra, Neeta; Gogri, Pratik; Mahajan, Shruti

    2016-10-01

    Ectopic lacrimal gland, being one of the choristomas, is comprised of lacrimal gland tissue outside the lacrimal gland fossa in the fronto-lateral part of the orbital roof. Ectopic lacrimal gland is a rare condition where the gland may be found in the orbit, eyelids, ocular adnexa or within the globe. Neoplastic transformation of such tissue may occur. A sixty-two-year old male patient presented with right eye proptosis and slight nasal displacement of the globe. Computerized tomography scan revealed a well-defined hypodense lesion of size 19 x 18 x 20 mm supero-lateral to lateral rectus muscle, with mild proptosis and thinning of the right lateral orbital wall. Excisional biopsy was performed through a lateral orbitotomy approach. A well circumscribed globular mass was removed from the right orbit, well behind the fossa for the lacrimal gland in the retrobulbar space. Histopathology was suggestive of pleomorphic adenoma of lacrimal gland. Pleomorphic adenoma is an epithelial tumor of the lacrimal gland which is extremely rare from an ectopic lacrimal gland and only few cases have been reported in literature till date.

  16. HMB-45 negative angiomyolipoma of the orbit: a case report and review of the literature.

    PubMed

    Lin, Che-Yu; Tsai, Chieh-Chih; Kau, Hui-Chuan; Yu, Wei-Kuang; Kao, Shu-Ching; Liu, Catherine Jui-Ling

    2016-01-11

    Angiomyolipoma is a benign mesenchymal tumor composed of variable amounts of smooth muscle, adipose tissue and thick-walled blood vessels, and usually named PEComas (perivascular epithelioid cell tumors). PEComas share overlapping histopathological features with epithelioid cells along a perivascular distribution and characteristic immunohistochemistry with coexpression of myoid and melanocytic markers (HMB-45 /or Melan-A). We report the first case of primary orbital angiomyolipoma with negative melanocytic marker. An 80-year-old Asian woman had a 2-year history of progressive swelling in the left upper eyelid. External examination revealed 3 cm of relative proptosis of the left eye and a palpable mass in the left superonasal orbit. Computed tomographic scan demonstrated a circumscribed, heterogeneous orbital mass. Excision biopsy was done and the histological finding demonstrated the orbital mass was composed of mature adipocytes, intermingled with spindle or oval-shaped cells, and accompanied by thick-walled blood vessels. Immunohistochemically, tumor cells were positive for CD34 and HHF-35, but negative for cytokeratin, HMB-45 and Melan-A. The diagnosis of angiomyolipoma was made. No recurrence was noted at 2-year follow-up. In our case, the HMB-45 negativity may be explained by the rarity of the epithelioid cells, and the HMB-45 positivity is often weaker or absent in spindle cells. Angiomyolipoma, although rare, should be added to the differential diagnosis of space-occupying orbital lesion.

  17. Reduction of Zygomatic Fractures Using the Carroll-Girard T-bar Screw.

    PubMed

    Baek, Ji Eun; Chung, Chan Min; Hong, In Pyo

    2012-09-01

    Zygomatic fractures are the second most common facial bone fractures encountered and treated by plastic surgeons. Stable fixation of fractured fragments after adequate exposure is critical for ensuring three-dimensional anatomic reduction. Between January 2008 and December 2010, 17 patients with zygomatic fractures were admitted to our hospital; there were 15 male and 2 female patients. The average age of the patients was 41 years (range, 19 to 75 years). We exposed the inferior orbital rim and zygomatic complex through a lateral brow, intraoral, and subciliary incisions, which allowed for visualization of the bone, and then the fractured parts were corrected using the Carroll-Girard T-bar screw. Postoperative complications such as malar asymmetry, diplopia, enophthalmos, and postoperative infection were not observed. Lower eyelid retraction and temporary ectropion occurred in 1 of the 17 patients. Functional and cosmetic results were excellent in nearly all of the cases. In this report, we describe using the Carroll-Girard T-bar screw for the reduction of zygomatic fractures. Because this instrument is easy to use and can rotate to any direction and vector, it can be used to correct displaced zygomatic bone more accurately and safely than other devices, without leaving facial scars.

  18. [Orbital alveolar rhabdomyosarcoma masked by ethmoid sinusitis in a 25-year-old].

    PubMed

    Sanz-Marco, E; España, E; Alamar, A; Pérez-Rojas, J; López-Prats, M J; Díaz-Llopis, M

    2014-05-01

    A 25-year-old woman with right subacute sinusitis, complained about discomfort in her right eye. Clinical manifestations and computed tomography were suggestive of sub-periosteal orbital ethmoid wall abscess, for which the patient underwent urgent drainage. A solid tumor was found, with a positive biopsy for alveolar rhabdomyosarcoma. Complete remission and resolution of orbital symptoms were achieved with chemotherapy and radiation therapy. Alveolar orbital rhabdomyosarcoma in adults is uncommon. Rhabdomyosarcoma has a high risk of spreading. It can simulate a sinusitis, as in our patient, early diagnosis and early treatment being especially important in these patients. Copyright © 2010 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  19. Temporal evolution of surface rupture deduced from coseismic multi-mode secondary fractures: Insights from the October 8, 2005 (Mw 7.6) Kashmir earthquake, NW Himalaya

    NASA Astrophysics Data System (ADS)

    Sayab, Mohammad; Khan, Muhammad Asif

    2010-10-01

    Detailed rupture-fracture analyses of some of the well-studied earthquakes have revealed that the geometrical arrangement of secondary faults and fractures can be used as a geological tool to understand the temporal evolution of slip produced during the mainshock. The October 8, 2005 Mw 7.6 Kashmir earthquake, NW Himalaya, surface rupture provides an opportunity to study a complex network of secondary fractures developed on the hanging wall of the fault scarp. The main fault scarp is clearly thrust-type, rupture length is ~ 75 ± 5 km and the overall trend of the rupture is NW-SE. We present the results of our detailed structural mapping of secondary faults and fractures at 1:100 scale, on the hanging wall of the southern end of the rupture in the vicinity of the Sar Pain. Secondary ruptures can be broadly classified as two main types, 1) normal faults and, (2) right-lateral strike-slip 'Riedel' fractures. The secondary normal faults are NW-SE striking, with a maximum 3.3 meter vertical displacement and 2.5 meter horizontal displacement. Estimated total horizontal extension across the secondary normal faults is 3.1-3.5%. We propose that the bending-moment and coseismic stress relaxation can explain the formation of secondary normal faults on the hanging wall of the thrust fault. The strike-slip 'Riedel' fractures form distinct sets of tension (T) and shear fractures (R', R, Y) with right-lateral displacement. Field observations revealed that the 'Riedel' fractures (T) cut the secondary normal faults. In addition, there is kinematic incompatibility and magnitude mismatch between the secondary normal faults and strike-slip 'Riedel' fractures. The cross-cutting relationship, geometric and magnitude incoherence implies a temporal evolution of slip from dip- to strike-slip during the mainshock faulting. The interpretation is consistent with the thrust fault plane solution with minor right-lateral strike-slip component.

  20. Management of comminuted proximal ulna fracture-dislocations using a multiplanar locking intramedullary nail.

    PubMed

    Edwards, Scott G; Argintar, Evan; Lamb, Joshua

    2011-06-01

    Intramedullary nails have been used for the fixation of olecranon fractures in an attempt to reduce the soft tissue irritation and resulting need for hardware removal seen with plating and tension banding. Further benefits include preservation of vascular supply, and increase stability and improved compression over some alternative techniques. Most intramedullary nails have been limited to simple olecranon fractures or osteotomies. One novel multiplanar, locking intramedullary nail, however, is indicated to stabilize all fracture patterns of the proximal ulna, including the coronoid. This particular locking nail has screws that radiate in multiple planes and form a fixed-angle lattice throughout the bone. The nail also has fixed-angle screws dedicated to the 3 parts of the coronoid: process tip, medial facet, and medial wall. This allows the nail to secure multiple fragments regardless of the fracture pattern's extent of instability. The objective of this article is to illustrate the recommended steps in reducing and stabilizing a comminuted proximal ulna fracture-dislocation using this multiplanar locking intramedullary nail.

  1. Laboratory Simulation of Flow through Single Fractured Granite

    NASA Astrophysics Data System (ADS)

    Singh, K. K.; Singh, D. N.; Ranjith, P. G.

    2015-05-01

    Laboratory simulation on fluid flow through fractured rock is important in addressing the seepage/fluid-in-rush related problems that occur during the execution of any civil or geological engineering projects. To understand the mechanics and transport properties of fluid through a fractured rock in detail and to quantify the sources of non-linearity in the discharge and base pressure relationship, fluid flow experiments were carried out on a cylindrical sample of granite containing a `single rough walled fracture'. These experiments were performed under varied conditions of confining pressures, σ 3 (5-40 MPa), which can simulate the condition occurring about 1,000 m below in the earth crust, with elevated base pressure, b p (up to 25 MPa) and by changing fracture roughness. The details of the methodologies involved and the observations are discussed here. The obtained results indicate that most of the data in the Q verses b p plot, fall on the straight line and the flow through the single fracture in granite obeys Darcy's law or the well-known "cubic law" even at high value of b p (=4 MPa) and σ 3 (=5 MPa) combination. The Reynolds number is quite sensitive to the b p, σ 3 and fracture roughness, and there is a critical b p, beyond which transition in flow occurs from laminar to turbulent. It is believed that such studies will be quite useful in identifying the limits of applicability of well know `cubic law', which is required for precise calculation of discharge and/or aperture in any practical issues and in further improving theoretical/numerical models associated with fluid flow through a single fracture.

  2. Penetrating maxillary sinus injury caused by a construction nail passing through the orbital cavity.

    PubMed

    Simsek, Tekin; Demir, Bulent; Yosma, Engin; Keles, Musa K; Abdullayev, Asef

    2014-03-01

    Because of its anatomic position, the orbit is frequently subject to trauma, leading to functional and cosmetic problems. After blunt trauma, orbital fractures can cause functional problems by trapping the periocular tissues without affecting the anatomic integrity of the globe. In comparison, high-energy penetrating injuries can cause serious consequences such as disrupting the lacrimal drainage system and causing loss of vision. In rare cases, however, penetration of the orbit by a foreign body can result in a treatable injury that causes no functional or cosmetic problems.This article presents a patient in whom a nail penetrated the orbit from the inferomedial margin and reached the maxillary sinus without damaging the globe, extraocular muscles, or lacrimal duct system. Reports of similar injuries are reviewed, focusing on the anatomic structures that might be traumatized, to guide the readers in considering the diagnosis and treatment of such injuries.

  3. [Orbital apex syndrome of the aspergillus etiology--a case report].

    PubMed

    Fric, E; Rehák, M; Vlcková, I; Burval, S; Chrapek, O; Rehák, J

    2007-04-01

    The authors present a case report of a patient, in whom after a head injury the monolateral blindness occurred. Because of autoimmune thrombocytopeny the patient was treated with long-term corticosteroids. The clinical findings corresponded with the orbital apex syndrome. According to the results of the CT and MRI examinations, the sphenoidotomy was indicated, and the histological findings verified fragments of paranasal sinuses' aspergiloma. During the next course of the disease, despite antimycotic therapy, the progression of the aspergiloma in to the anterior cranial fossa occurred. Invasive sino-orbital aspergilosis, after the penetration of the infectious agent across the wall of the sinus, may cause the orbital apex syndrome with paralysis of all three cranial nerves innervating the extraocular muscles, sensoric defect in the area of the ophthalmic nerve and the involvement of the optic nerve.

  4. Orbital extraskeletal osteosarcoma following enucleation in a cat: a case report.

    PubMed

    Groskopf, Brooke S; Dubielzig, Richard R; Beaumont, Stephanie L

    2010-05-01

    We present a unique case of a feline orbital extraskeletal osteosarcoma that developed 5 years post-enucleation. In 2002, an ophthalmologist enucleated the left eye of a 2-year-old neutered male DSH and submitted it to the Comparative Ocular Pathology Laboratory of Wisconsin (COPLOW). COPLOW diagnosed the left eye with feline diffuse iris melanoma. In June 2007, the cat presented to another veterinarian for moderate swelling of the enucleation site. Palpation suggested a firm mass along the lateral orbital rim and an exploratory orbitotomy revealed a cyst with a mass adhered to it and the ventrolateral orbital rim. The cyst and mass were excised by the veterinarian and submitted to COPLOW. COPLOW diagnosed the tissue as an orbital conjunctival inclusion cyst and an acquired orbital osteosarcoma. Following the enucleation, retained conjunctival epithelium became embedded in the connective tissue of the orbit and caused a cyst to develop. The cyst wall consisted of a myofibroblastic collagen-rich matrix and acted as a nidus of chronic irritation and tumor growth. This orbital osteosarcoma resembles feline vaccine-associated sarcomas (VAS), feline post-traumatic ocular sarcomas, and microchip-associated sarcomas in terms of it histopathology and its hypothesized pathogenesis related to exposure to antigenic material such as implanted epithelium, lens protein, vaccine components, and microchips as foreign bodies.

  5. Effect of Random Natural Fractures on Hydraulic Fracture Propagation Geometry in Fractured Carbonate Rocks

    NASA Astrophysics Data System (ADS)

    Liu, Zhiyuan; Wang, Shijie; Zhao, Haiyang; Wang, Lei; Li, Wei; Geng, Yudi; Tao, Shan; Zhang, Guangqing; Chen, Mian

    2018-02-01

    Natural fractures have a significant influence on the propagation geometry of hydraulic fractures in fractured reservoirs. True triaxial volumetric fracturing experiments, in which random natural fractures are created by placing cement blocks of different dimensions in a cuboid mold and filling the mold with additional cement to create the final test specimen, were used to study the factors that influence the hydraulic fracture propagation geometry. These factors include the presence of natural fractures around the wellbore, the dimension and volumetric density of random natural fractures and the horizontal differential stress. The results show that volumetric fractures preferentially formed when natural fractures occurred around the wellbore, the natural fractures are medium to long and have a volumetric density of 6-9%, and the stress difference is less than 11 MPa. The volumetric fracture geometries are mainly major multi-branch fractures with fracture networks or major multi-branch fractures (2-4 fractures). The angles between the major fractures and the maximum horizontal in situ stress are 30°-45°, and fracture networks are located at the intersections of major multi-branch fractures. Short natural fractures rarely led to the formation of fracture networks. Thus, the interaction between hydraulic fractures and short natural fractures has little engineering significance. The conclusions are important for field applications and for gaining a deeper understanding of the formation process of volumetric fractures.

  6. Fractal characterization of a fractured chalk reservoir - The Laegerdorf case

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

    Stoelum, H.H.; Koestler, A.G.; Feder, J.

    1991-03-01

    What is the matrix block size distribution of a fractured reservoir In order to answer this question and assess the potential of fractal geometry as a method of characterization of fracture networks, a pilot study has been done of the fractured chalk quarry in Laegerdorf. The fractures seen on the quarry walls were traced in the field for a total area of {approximately}200 {times} 45 m. The digitized pictures have been analyzed by a standard box-counting method. This analysis gave a fractal dimension of similarity varying from 1.33 for fractured areas between faults, to 1.43 for the fault zone, andmore » 1.53 for the highly deformed fault gouge. The amplitude showed a similar trend. The fractal dimension for the whole system of fractures is {approximately}1.55. In other words, fracture networks in chalk have a nonlinear, fractal geometry, and so matrix block size is a scaling property of chalk reservoirs. In terms of rock mechanics, the authors interpret the variation of the fractal dimension as follows: A small fractal dimension and amplitude are associated with brittle deformation in the elastic regime, while a large fractal dimension and amplitude are associated with predominantly ductile, strain softening deformation in the plastic regime. The interaction between the two regimes of deformation in the rock body is a key element of successful characterization and may be approached by seeing the rock as a non-Newtonian viscoelastic medium. The fractal dimension for the whole is close to a material independent limit that constrains the development of fractures.« less

  7. CO2 injection into fractured peridotites: a reactive percolation experiment

    NASA Astrophysics Data System (ADS)

    Escario, S.; Godard, M.; Gouze, P.; Leprovost, R.; Luquot, L.; Garcia-Rios, M.

    2017-12-01

    Mantle peridotites have the potential to trap CO2 as carbonates. This process observed in ophiolites and in oceanic environments provides a long term and safe storage for CO2. It occurs as a part of a complex suite of fluid-rock reactions involving silicate dissolution and precipitation of hydrous phases, carbonates and minor phases that may in turn modify the hydrodynamic properties and the reactivity of the reacted rocks. The efficiency and lastingness of the process require the renewal of fluids at the mineral-fluid interface. Fractures are dominant flow paths in exhumed mantle sections. This study aims at better understanding the effect of CO2-enriched saline fluids on hydrodynamic and chemical processes through fractured peridotites. Experiments were performed using the reactive percolation bench ICARE Lab 3 - Géosciences Montpellier. It allows monitoring the permeability changes during experiments. Effluents are recurrently sampled for analysing cation concentration, pH and alkalinity. Reacted rock samples were characterized by high resolution X-ray microtomography (ESRF ID19, Grenoble, France) and SEM. Experiments consisted in injecting CO2-enriched brines (NaCl 0.5 M) at a rate of 6 mL.h-1 into artificially fractured cores (9 mm diameter × 20 mm length) of Oman harzburgites at T=170°C and Ptotal = 25 MPa for up to 2 weeks. Fractures are of few µm apertures with rough walls. Three sets of experiments were performed at increasing value of [CO2] (0, 0.1 and 1 mol/kg). All experiments showed a decrease in permeability followed by steady state regime that can be caused by a decrease in the roughness of fracture walls (dissolution dominated process), thus favouring fracture closing, or by the precipitation of secondary phases. Maximum enrichments in Mg, Fe and Ca of the effluent fluids occur during the first 2 hours of the experiments whereas Si displays a maximum enrichment at t = 20 h, suggesting extensive dissolution. Maximum enrichments are observed with

  8. Fragmentation of wall rock garnets during deep crustal earthquakes

    PubMed Central

    Austrheim, Håkon; Dunkel, Kristina G.; Plümper, Oliver; Ildefonse, Benoit; Liu, Yang; Jamtveit, Bjørn

    2017-01-01

    Fractures and faults riddle the Earth’s crust on all scales, and the deformation associated with them is presumed to have had significant effects on its petrological and structural evolution. However, despite the abundance of directly observable earthquake activity, unequivocal evidence for seismic slip rates along ancient faults is rare and usually related to frictional melting and the formation of pseudotachylites. We report novel microstructures from garnet crystals in the immediate vicinity of seismic slip planes that transected lower crustal granulites during intermediate-depth earthquakes in the Bergen Arcs area, western Norway, some 420 million years ago. Seismic loading caused massive dislocation formations and fragmentation of wall rock garnets. Microfracturing and the injection of sulfide melts occurred during an early stage of loading. Subsequent dilation caused pervasive transport of fluids into the garnets along a network of microfractures, dislocations, and subgrain and grain boundaries, leading to the growth of abundant mineral inclusions inside the fragmented garnets. Recrystallization by grain boundary migration closed most of the pores and fractures generated by the seismic event. This wall rock alteration represents the initial stages of an earthquake-triggered metamorphic transformation process that ultimately led to reworking of the lower crust on a regional scale. PMID:28261660

  9. Prospecting from Orbit

    NASA Image and Video Library

    2017-09-04

    The combination of morphological and topographic information from stereo images from NASA's Mars Reconnaissance Orbiter, as well as compositional data from near-infrared spectroscopy has been proven to be a powerful tool for understanding the geology of Mars. Beginning with the OMEGA instrument on the European Space Agency's Mars Express orbiter in 2003, the surface of Mars has been examined at near-infrared wavelengths by imaging spectrometers that are capable of detecting specific minerals and mapping their spatial extent. The CRISM (Compact Reconnaissance Imaging Spectrometer for Mars) instrument on our orbiter is a visible/near-infrared imaging spectrometer, and the HiRISE camera works together with it to document the appearance of mineral deposits detected by this orbital prospecting. Mawrth Vallis is one of the regions on Mars that has attracted much attention because of the nature and diversity of the minerals identified by these spectrometers. It is a large, ancient outflow channel on the margin of the Southern highlands and Northern lowlands. Both the OMEGA and CRISM instruments have detected clay minerals here that must have been deposited in a water-rich environment, probably more than 4 billion years ago. For this reason, Mawrth Vallis is one of the two candidate landing sites for the future Mars Express Rover Mission planned by the European Space Agency. This image was targeted on a location where the CRISM instrument detected a specific mineral called alunite, KAl3(SO4)2(OH)6. Alunite is a hydrated aluminum potassium sulfate, a mineral that is notable because it must have been deposited in a wet acidic environment, rich in sulfuric acid. Our image shows that the deposit is bright and colorful, and extensively fractured. The width of the cutout is 1.2 kilometers. The map is projected here at a scale of 50 centimeters (19.7 inches) per pixel. [The original image scale is 60.1 centimeters (23.7 inches) per pixel (with 2 x 2 binning); objects on the order

  10. Domain wall in a quantum anomalous Hall insulator as a magnetoelectric piston

    NASA Astrophysics Data System (ADS)

    Upadhyaya, Pramey; Tserkovnyak, Yaroslav

    2016-07-01

    We theoretically study the magnetoelectric coupling in a quantum anomalous Hall insulator state induced by interfacing a dynamic magnetization texture to a topological insulator. In particular, we propose that the quantum anomalous Hall insulator with a magnetic configuration of a domain wall, when contacted by electrical reservoirs, acts as a magnetoelectric piston. A moving domain wall pumps charge current between electrical leads in a closed circuit, while applying an electrical bias induces reciprocal domain-wall motion. This pistonlike action is enabled by a finite reflection of charge carriers via chiral modes imprinted by the domain wall. Moreover, we find that, when compared with the recently discovered spin-orbit torque-induced domain-wall motion in heavy metals, the reflection coefficient plays the role of an effective spin-Hall angle governing the efficiency of the proposed electrical control of domain walls. Quantitatively, this effective spin-Hall angle is found to approach a universal value of 2, providing an efficient scheme to reconfigure the domain-wall chiral interconnects for possible memory and logic applications.

  11. A Single-Center Review of Facial Fractures as the Result of High-Speed Projectile Injuries

    PubMed Central

    Liu, Farrah C.; Halsey, Jordan N.; Hoppe, Ian C.; Ciminello, Frank S.; Lee, Edward S.; Granick, Mark S.

    2018-01-01

    Purpose: Gunshot injuries to the face that result in fractures of the underlying skeleton present a challenge in management. The goal of this study was to evaluate patterns of facial fractures as a result of gunshot injuries and strategies for management. Methods: A retrospective review of facial fractures resulting from gunshot injuries in a level 1 trauma center was performed for the years 2000 to 2012. Data were collected for patient demographics, fracture distribution, concomitant injuries, and surgical management strategies. Results: A total of 190 patients sustained facial fractures from a gunshot injury. The average age was 29.9 years, and 90% were male. Sixteen injuries were self-inflicted. The most common fractures were of the mandible and the orbit. Uncontrolled hemorrhage was noted on presentation in 68 patients; 100 patients were intubated on arrival. The average Glasgow Coma Scale score on arrival was 11.9. Concomitant injuries included skull fracture, intracranial hemorrhage, and intrathoracic injury. Surgical management was required in 89 patients. Nine patients required soft-tissue coverage. Thirty patients expired. Conclusion: Gunshot injuries to the face resulting in fractures of the underlying skeleton have high instances of morbidity and mortality. Life-threatening concomitant injuries can complicate management of facial fractures in this population. PMID:29713397

  12. Pediatric craniofacial fractures due to violence: comparing violent and nonviolent mechanisms of injury.

    PubMed

    Mericli, Alexander F; DeCesare, Gary E; Zuckerbraun, Noel S; Kurland, Kristen S; Grunwaldt, Lorelei; Vecchione, Lisa; Losee, Joseph E

    2011-07-01

    This study examines the epidemiologic data of pediatric craniofacial fractures secondary to violence, comparing these data to craniofacial fractures sustained from all other causes. A retrospective review was completed on all patients who presented to the emergency department of a major urban children's hospital from 2000 to 2005 with a craniofacial fracture. Data were compared between patients with fractures due to violent and nonviolent mechanisms. Socioeconomic analysis was performed using Geographic Information System mapping and 2000 US Census data by postal code. One thousand five hundred twenty-eight patients were diagnosed with skull and/or facial fractures. Isolated skull fractures were excluded, leaving 793 patients in the study. Ninety-eight children were injured due to violence, and 695 were injured from a nonviolent cause. Patients with violence-related fractures were more likely to be older, male, and nonwhite and live in a socioeconomically depressed area. A greater number of patients with violence-related injuries sustained nasal and mandible angle fractures, whereas more patients with non-violence-related injuries sustained skull and orbital fractures. Those with violence-related craniofacial fractures had a lower percentage of associated multiorgan system injuries and a lower rate of hospital admissions and intensive care unit admissions. The rate of open reduction and internal fixation for craniofacial fractures was similar in both groups. Patients with violence-related fractures had fewer associated serious injuries and lower morbidity and lived in a more socioeconomically depressed area. The information gained from this descriptive study improves our ability to characterize this population of pediatric patients and to identify the associated constellation of injuries in such fractures.

  13. Paratrooper's Ankle Fracture: Posterior Malleolar Fracture

    PubMed Central

    Young, Ki Won; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

    2015-01-01

    Background We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Methods Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. Results The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Conclusions Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were

  14. Paratrooper's ankle fracture: posterior malleolar fracture.

    PubMed

    Young, Ki Won; Kim, Jin-su; Cho, Jae Ho; Kim, Hyung Seuk; Cho, Hun Ki; Lee, Kyung Tai

    2015-03-01

    We assessed the frequency and types of ankle fractures that frequently occur during parachute landings of special operation unit personnel and analyzed the causes. Fifty-six members of the special force brigade of the military who had sustained ankle fractures during parachute landings between January 2005 and April 2010 were retrospectively analyzed. The injury sites and fracture sites were identified and the fracture types were categorized by the Lauge-Hansen and Weber classifications. Follow-up surveys were performed with respect to the American Orthopedic Foot and Ankle Society ankle-hindfoot score, patient satisfaction, and return to preinjury activity. The patients were all males with a mean age of 23.6 years. There were 28 right and 28 left ankle fractures. Twenty-two patients had simple fractures and 34 patients had comminuted fractures. The average number of injury and fractures sites per person was 2.07 (116 injuries including a syndesmosis injury and a deltoid injury) and 1.75 (98 fracture sites), respectively. Twenty-three cases (41.07%) were accompanied by posterior malleolar fractures. Fifty-five patients underwent surgery; of these, 30 had plate internal fixations. Weber type A, B, and C fractures were found in 4, 38, and 14 cases, respectively. Based on the Lauge-Hansen classification, supination-external rotation injuries were found in 20 cases, supination-adduction injuries in 22 cases, pronation-external rotation injuries in 11 cases, tibiofibular fractures in 2 cases, and simple medial malleolar fractures in 2 cases. The mean follow-up period was 23.8 months, and the average follow-up American Orthopedic Foot and Ankle Society ankle-hindfoot score was 85.42. Forty-five patients (80.36%) reported excellent or good satisfaction with the outcome. Posterior malleolar fractures occurred in 41.07% of ankle fractures sustained in parachute landings. Because most of the ankle fractures in parachute injuries were compound fractures, most cases had to

  15. Discrete Fracture Network Characterization of Fractured Shale Reservoirs with Implications to Hydraulic Fracturing Optimization

    NASA Astrophysics Data System (ADS)

    Jin, G.

    2016-12-01

    Shales are important petroleum source rocks and reservoir seals. Recent developments in hydraulic fracturing technology have facilitated high gas production rates from shale and have had a strong impact on the U.S. gas supply and markets. Modeling of effective permeability for fractured shale reservoirs has been challenging because the presence of a fracture network significantly alters the reservoir hydrologic properties. Due to the frequent occurrence of fracture networks, it is of vital importance to characterize fracture networks and to investigate how these networks can be used to optimize the hydraulic fracturing. We have conducted basic research on 3-D fracture permeability characterization and compartmentization analyses for fractured shale formations, which takes the advantages of the discrete fracture networks (DFN). The DFN modeling is a stochastic modeling approach using the probabilistic density functions of fractures. Three common scenarios of DFN models have been studied for fracture permeability mapping using our previously proposed techniques. In DFN models with moderately to highly concentrated fractures, there exists a representative element volume (REV) for fracture permeability characterization, which indicates that the fractured reservoirs can be treated as anisotropic homogeneous media. Hydraulic fracturing will be most effective if the orientation of the hydraulic fracture is perpendicular to the mean direction of the fractures. A DFN model with randomized fracture orientations, on the other hand, lacks an REV for fracture characterization. Therefore, a fracture permeability tensor has to be computed from each element. Modeling of fracture interconnectivity indicates that there exists no preferred direction for hydraulic fracturing to be most effective oweing to the interconnected pathways of the fracture network. 3-D fracture permeability mapping has been applied to the Devonian Chattanooga Shale in Alabama and the results suggest that an

  16. Orbital Debris Impact Damage to Reusable Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Robinson, Jennifer H.

    1998-01-01

    In an effort by the National Aeronautics and Space Administration (NASA), hypervelocity impact tests were performed on thermal protection systems (TPS) applied on the external surfaces of reusable launch vehicles (RLV) to determine the potential damage from orbital debris impacts. Three TPS types were tested, bonded to composite structures representing RLV fuel tank walls. The three heat shield materials tested were Alumina-Enhanced Thermal Barrier-12 (AETB-12), Flexible Reusable Surface Insulation (FRSI), and Advanced Flexible Reusable Surface Insulation (AFRSI). Using this test data, predictor equations were developed for the entry hole diameters in the three TPS materials, with correlation coefficients ranging from 0.69 to 0.86. Possible methods are proposed for approximating damage occurring at expected orbital impact velocities higher than tested, with references to other published work.

  17. Comparison between spin-orbit torques measured by domain-wall motions and harmonic measurements

    NASA Astrophysics Data System (ADS)

    Kim, Joo-Sung; Nam, Yune-Seok; Kim, Dae-Yun; Park, Yong-Keun; Park, Min-Ho; Choe, Sug-Bong

    2018-05-01

    Here we report the comparison of the spin torque efficiencies measured by three different experimental schemes for Pt/Co/X stacks with material X (= Pt, Ta, Ti, Al, Au, Pd, and Ru. 7 materials). The first two spin torque efficiencies ɛDW (1 ) and ɛDW (2 ) are quantified by the measurement of spin-torque-induced effective field for domain-wall depinning and creeping motions, respectively. The last one—longitudinal spin torque efficiency ɛL—is measured by harmonic signal measurement of the magnetization rotation with uniform magnetization configuration. The results confirm that, for all measured Pt/Co/X stacks, ɛDW (1 ) and ɛDW (2 ) are exactly consistent to each other and these two efficiencies are roughly proportional to ɛL with proportionality constant π/2, which comes from the integration over the domain-wall configuration.

  18. Fractal vein distributions within a fault-fracture mesh in an exhumed accretionary mélange, Chrystalls Beach Complex, New Zealand

    NASA Astrophysics Data System (ADS)

    Fagereng, Åke

    2011-05-01

    A well developed fault-fracture mesh is observed in the Chrystalls Beach Complex, an accretionary mélange within the Otago Schist on the South Island of New Zealand. In this study, an analysis of vein thicknesses and clustering of veins is presented. Both shear and extension veins have a power-law thickness distribution. Measures of vein spacing best fit a power-law distribution, but a small data set limits this interpretation to a small fractal range. Vein clustering varies from random to moderately clustered between outcrops, and is the greatest where a large proportion of relatively competent blocks occurs within the mélange. Fractures are distributed within the mélange matrix, and this localized deformation requires heterogeneity in rheology and/or fluid pressure distribution, whereas pervasive, distributed deformation occurs in relatively homogeneous rock. The overall trend of this deformation being mainly accommodated by thin veins required that new fractures formed preferentially over refracturing existing veins, which highlights the distributed nature of deformation within a fault-fracture mesh. The predominance of new fractures may result from vein material being stronger than the cleaved wall rock, such that wall rock failure occurred instead of reopening of pre-existing shear and extension veins.

  19. Role of MRI in hip fractures, including stress fractures, occult fractures, avulsion fractures.

    PubMed

    Nachtrab, O; Cassar-Pullicino, V N; Lalam, R; Tins, B; Tyrrell, P N M; Singh, J

    2012-12-01

    MR imaging plays a vital role in the diagnosis and management of hip fractures in all age groups, in a large spectrum of patient groups spanning the elderly and sporting population. It allows a confident exclusion of fracture, differentiation of bony from soft tissue injury and an early confident detection of fractures. There is a spectrum of MR findings which in part is dictated by the type and cause of the fracture which the radiologist needs to be familiar with. Judicious but prompt utilisation of MR in patients with suspected hip fractures has a positive therapeutic impact with healthcare cost benefits as well as social care benefits. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  20. Effect of air bags and restraining devices on the pattern of facial fractures in motor vehicle crashes.

    PubMed

    Simoni, Payman; Ostendorf, Robert; Cox, Artemus J

    2003-01-01

    To examine the relationship between the use of restraining devices and the incidence of specific facial fractures in motor vehicle crashes. Retrospective analysis of patients with facial fractures following a motor vehicle crash. University of Alabama at Birmingham Hospital level I trauma center from 1996 to 2000. Of 3731 patients involved in motor vehicle crashes, a total of 497 patients were found to have facial fractures as determined by International Classification of Diseases, Ninth Revision (ICD-9) codes. Facial fractures were categorized as mandibular, orbital, zygomaticomaxillary complex (ZMC), and nasal. Use of seat belts alone was more effective in decreasing the chance of facial fractures in this population (from 17% to 8%) compared with the use of air bags alone (17% to 11%). The use of seat belts and air bags together decreased the incidence of facial fractures from 17% to 5%. Use of restraining devices in vehicles significantly reduces the chance of incurring facial fractures in a severe motor vehicle crash. However, use of air bags and seat belts does not change the pattern of facial fractures greatly except for ZMC fractures. Air bags are least effective in preventing ZMC fractures. Improving the mechanics of restraining devices might be needed to minimize facial fractures.

  1. Fracture network topology and characterization of structural permeability

    NASA Astrophysics Data System (ADS)

    Hansberry, Rowan; King, Rosalind; Holford, Simon

    2017-04-01

    There are two fundamental requirements for successful geothermal development: elevated temperatures at accessible depths, and a reservoir from which fluids can be extracted. The Australian geothermal sector has successfully targeted shallow heat, however, due in part to the inherent complexity of targeting permeability, obtaining adequate flow rates for commercial production has been problematic. Deep sedimentary aquifers are unlikely to be viable geothermal resources due to the effects of diagenetic mineral growth on rock permeability. Therefore, it is likely structural permeability targets, exploiting natural or induced fracture networks will provide the primary means for fluid flow in geothermal, as well as unconventional gas, reservoirs. Recent research has focused on the pattern and generation of crustal stresses across Australia, while less is known about the resultant networks of faults, joints, and veins that can constitute interconnected sub-surface permeability pathways. The ability of a fracture to transmit fluid is controlled by the orientation and magnitude of the in-situ stress field that acts on the fracture walls, rock strength, and pore pressure, as well as fracture properties such as aperture, orientation, and roughness. Understanding the distribution, orientation and character of fractures is key to predicting structural permeability. This project focuses on extensive mapping of fractures over various scales in four key Australian basins (Cooper, Otway, Surat and Perth) with the potential to host geothermal resources. Seismic attribute analysis is used in concert with image logs from petroleum wells, and field mapping to identify fracture networks that are usually not resolved in traditional seismic interpretation. We use fracture network topology to provide scale-invariant characterisation of fracture networks from multiple data sources to assess similarity between data sources, and fracture network connectivity. These results are compared with

  2. Internal Arrangement of the Skylab Orbital Workshop

    NASA Technical Reports Server (NTRS)

    1971-01-01

    The wardroom deck of the Orbital Workshop, showing the living quarters arrangement, is seen here in good detail. From left to right is the dining area, waste management, and sleeping quarters. Portable restraints are on the wall beside the sleeping quarters. The ergometer for the vectorcardiograph (Experiment - M093) and lower-body Negative Pressure (Experiment M092) unit, used in some of the medical experiments, are in the foreground. The round brown object in the center of the room is the trash disposal airlock.

  3. The association between Chance fractures and intra-abdominal injuries revisited: a multicenter review.

    PubMed

    Tyroch, Alan H; McGuire, Emmett L; McLean, Susan F; Kozar, Rosemary A; Gates, Keith A; Kaups, Krista L; Cook, Charles; Cowgill, Sarah M; Griswold, John A; Sue, Larry A; Craun, Michael L; Price, Jan

    2005-05-01

    The association between Chance fractures and intra-abdominal injuries is reported to be as high as 89 per cent. Because prior studies were small series or case reports, we conducted a multicenter review to learn the true association between Chance fractures and intra-abdominal injuries as well as diagnostic trends. Trauma registry data, medical records, and radiology reports from 7 trauma centers were used to characterize 79 trauma patients with Chance fractures. Initial methods of abdominal assessment were computed tomography (CT) scan (79%), clinical examination (16%), and diagnostic peritoneal lavage (DPL) (5%). Twenty-six (33%) patients had intraabdominal injuries of which hollow viscus injuries predominated (22%). Twenty patients (25%) underwent laparotomy. The presence of an abdominal wall contusion and automobile restraint use were highly predictive of intra-abdominal injury and the need for laparotomy. The association between a Chance fracture and intra-abdominal injury is not as high as previously reported. CT scan has become the primary modality to assess the abdominal cavity of patients with Chance fractures, whereas the role of DPL has diminished.

  4. The implications of different lateral wall thicknesses on surgical access to the maxillary sinus.

    PubMed

    Lim, Ee Lian; Ngeow, Wei Cheong; Lim, Daniel

    2017-11-27

    The objective of this study was to measure the topographic thickness of the lateral wall of the maxillary sinus in selected Asian populations. Measurements were made on the lateral walls of maxillary sinuses recorded using CBCT in a convenient sample of patients attending an Asian teaching hospital. The points of measurement were the intersections between the axes along the apices of the canine, first premolar, and second premolar and along the mesiobuccal and distobuccal apices of the first and second molars and horizontal planes 10 mm, 20 mm, 30 mm and 40 mm beneath the orbital floor. The CBCT images of 109 patients were reviewed. The mean age of the patients was 33.0 (SD 14.8) years. Almost three quarters (71.8%) of the patients were male. The mean bone thickness decreased beginning at the 10-mm level and continuing to 40 mm below the orbital floor. Few canine regions showed encroachment of the maxillary sinus. The thickness of the buccal wall gradually increased from the canine region (where sinus encroachment of the canine region was present) to the first molar region, after which it decreased to the thickness observed at the canine region. The buccal wall of the maxillary sinus became thicker anteroposteriorly, except in the region of the second molar, and thinner superoinferiorly. These changes will affect the approach used to osteotomize the lateral sinus wall for oral surgery and for the sinus lift procedure.

  5. Construction and geometric stability of physiological flow rate wall-less stenosis phantoms.

    PubMed

    Ramnarine, K V; Anderson, T; Hoskins, P R

    2001-02-01

    Wall-less flow phantoms are preferred for ultrasound (US) because tissue-mimicking material (TMM) with good acoustical properties can be made and cast to form anatomical models. The construction and geometrical stability of wall-less TMM flow phantoms is described using a novel method of sealing to prevent leakage of the blood-mimicking fluid (BMF). Wall-less stenosis flow models were constructed using a robust agar-based TMM and sealed using reticulated foam at the inlet and outlet tubes. There was no BMF leakage at the highest flow rate of 2.8 L/min in 0%, 35% and 57% diameter reduction stenoses models. Failure of the 75% stenosis model, due to TMM fracture, occurred at maximum flow rate of 2 L/min (mean velocity 10 m/s within the stenosis). No change of stenosis geometry was measured over 4 days. The construction is simple and effective and extends the possibility for high flow rate studies using robust TMM wall-less phantoms.

  6. Rise of Racetrack Memory! Domain Wall Spin-Orbitronics

    NASA Astrophysics Data System (ADS)

    Parkin, Stuart

    Memory-storage devices based on the current controlled motion of a series of domain walls (DWs) in magnetic racetracks promise performance and reliability beyond that of conventional magnetic disk drives and solid state storage devices (1). Racetracks that are formed from atomically thin, perpendicularly magnetized nano-wires, interfaced with adjacent metal layers with high spin-orbit coupling, give rise to domain walls that exhibit a chiral Néel structure (2). These DWs can be moved very efficiently with current via chiral spin-orbit torques (2,3). Record-breaking current-induced DW speeds exceeding 1,000 m/sec are found in synthetic antiferromagnetic structures (3) in which the net magnetization of the DWs is tuned to almost zero, making them ``invisible''. Based on these recent discoveries, Racetrack Memory devices have the potential to operate on picosecond timescales and at densities more than 100 times greater than other memory technologies. (1) S.S.P. Parkin et al., Science 320, 5873 (2008); S.S.P. Parkin and S.-H. Yang, Nat. Nano. 10, 195 (2015). (2) K.-S. Ryu metal. Nat. Nano. 8, 527 (2013). (3) S.-H. Yang, K.-S. Ryu and S.S.P. Parkin, Nat. Nano. 10, 221 (2015). (4). S.S.P. Parkin, Phys. Rev. Lett. 67, 3598 (1991).

  7. Numerical Modelling of Extended Leak-Off Test with a Pre-Existing Fracture

    NASA Astrophysics Data System (ADS)

    Lavrov, A.; Larsen, I.; Bauer, A.

    2016-04-01

    Extended leak-off test (XLOT) is one of the few techniques available for stress measurements in oil and gas wells. Interpretation of the test is often difficult since the results depend on a multitude of factors, including the presence of natural or drilling-induced fractures in the near-well area. Coupled numerical modelling of XLOT has been performed to investigate the pressure behaviour during the flowback phase as well as the effect of a pre-existing fracture on the test results in a low-permeability formation. Essential features of XLOT known from field measurements are captured by the model, including the saw-tooth shape of the pressure vs injected volume curve, and the change of slope in the pressure vs time curve during flowback used by operators as an indicator of the bottomhole pressure reaching the minimum in situ stress. Simulations with a pre-existing fracture running from the borehole wall in the radial direction have revealed that the results of XLOT are quite sensitive to the orientation of the pre-existing fracture. In particular, the fracture initiation pressure and the formation breakdown pressure increase steadily with decreasing angle between the fracture and the minimum in situ stress. Our findings seem to invalidate the use of the fracture initiation pressure and the formation breakdown pressure for stress measurements or rock strength evaluation purposes.

  8. Numerical Analysis of AHSS Fracture in a Stretch-bending Test

    NASA Astrophysics Data System (ADS)

    Luo, Meng; Chen, Xiaoming; Shi, Ming F.; Shih, Hua-Chu

    2010-06-01

    Advanced High Strength Steels (AHSS) are increasingly used in the automotive industry due to their superior strength and substantial weight reduction advantage. However, their limited ductility gives rise to numerous manufacturing issues. One of them is the so-called `shear fracture' often observed on tight radii during stamping processes. Since traditional approaches, such as the Forming Limit Diagram (FLD), are unable to predict this type of fracture, efforts have been made to develop failure criteria that can predict shear fractures. In this paper, a recently developed Modified Mohr-Coulomb (MMC) ductile fracture criterion[1] is adopted to analyze the failure behavior of a Dual Phase (DP) steel sheet during stretch bending operations. The plasticity and ductile fracture of the present sheet are fully characterized by the Hill'48 orthotropic model and the MMC fracture model respectively. Finite Element models with three different element types (3D, shell and plane strain) were built for a Stretch Forming Simulator (SFS) test and numerical simulations with four different R/t ratios (die radius normalized by sheet thickness) were performed. It has been shown that the 3D and shell element models can accurately predict the failure location/mode, the upper die load-displacement responses as well as the wall stress and wrap angle at the onset of fracture for all R/t ratios. Furthermore, a series of parametric studies were conducted on the 3D element model, and the effects of tension level (clamping distance) and tooling friction on the failure modes/locations were investigated.

  9. Effective Wettability of Heterogenous Fracture Surfaces Using the Lattice-Boltzmann Method

    NASA Astrophysics Data System (ADS)

    E Santos, J.; Prodanovic, M.; Landry, C. J.

    2017-12-01

    Fracture walls in the subsurface are often structured by minerals of different composition (potentially further altered in contact with fluids during hydrocarbon extraction or CO2 sequestration), this yields in a heterogeneous wettability of the surface in contact with the fluids. The focus of our work is to study how surfaces presenting different mineralogy and roughness affect multiphase flow in fractures. Using the Shan-Chen model of the lattice-Boltzmann method (LBM) we define fluid interaction and surface attraction parameters to simulate a system of a wetting and a non-wetting fluid. In this work, we use synthetically created fractures presenting different arrangements of wetting and non-wetting patches, and with or without roughness; representative of different mineralogy, similar workflow can be applied to fractures extracted from X-ray microtomography images of fractures porous media. The results from the LBM simulations provide an insight on how the distribution of mineralogy and surface roughness are related with the observed macroscopic contact angle. We present a comparison between the published analytical models, and our results based on surface areas, spatial distribution and local fracture aperture. The understanding of the variables that affect the contact angle is useful for the comprehension of multiphase processes in naturally fractured reservoirs like primary oil production, enhanced oil recovery and CO2 sequestration. The macroscopic contact angle analytical equations for heterogeneous surfaces with variable roughness are no longer valid in highly heterogeneous systems; we quantify the difference thus offering an alternative to analytical models.

  10. Stress-induced, time-dependent fracture closure at hydrothermal conditions

    USGS Publications Warehouse

    Beeler, N.M.; Hickman, S.H.

    2004-01-01

    Time-dependent closure of fractures in quartz was measured in situ at 22-530??C temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working-distance microscope, and reflected-light interferometry. Thus the fracture volume and geometry can be measured as a function of time, temperature, and water pressure. Relatively uniform closure occurs rapidly at temperatures and pressures where quartz becomes significantly soluble in water. During closure the aperture is reduced by as much as 80% in a few hours. We infer that this closure results from the dissolution of small particles or asperities that prop the fracture open. The driving force for closure via dissolution of the prop is the sum of three chemical potential terms: (1) the dissolution potential, proportional to the logarithm of the degree of undersaturation of the solution; (2) the coarsening potential, proportional to the radius of curvature of the prop; and (3) the pressure solution potential, proportional to the effective normal stress at the contact between propping particles and the fracture wall. Our observations suggest that closure is controlled by a pressure solution-like process. The aperture of dilatant fractures and microcracks in the Earth that are similar to those in our experiments, such as ones generated from thermal stressing or brittle failure during earthquake rupture and slip, will decrease rapidly with time, especially if the macroscopic stress is nonhydrostatic.

  11. Stress-induced, time-dependent fracture closure at hydrothermal conditions

    NASA Astrophysics Data System (ADS)

    Beeler, N. M.; Hickman, S. H.

    2004-02-01

    Time-dependent closure of fractures in quartz was measured in situ at 22-530°C temperature and 0.1-150 MPa water pressure. Unlike previous crack healing and rock permeability studies, in this study, fracture aperture is monitored directly and continuously using a windowed pressure vessel, a long-working-distance microscope, and reflected-light interferometry. Thus the fracture volume and geometry can be measured as a function of time, temperature, and water pressure. Relatively uniform closure occurs rapidly at temperatures and pressures where quartz becomes significantly soluble in water. During closure the aperture is reduced by as much as 80% in a few hours. We infer that this closure results from the dissolution of small particles or asperities that prop the fracture open. The driving force for closure via dissolution of the prop is the sum of three chemical potential terms: (1) the dissolution potential, proportional to the logarithm of the degree of undersaturation of the solution; (2) the coarsening potential, proportional to the radius of curvature of the prop; and (3) the pressure solution potential, proportional to the effective normal stress at the contact between propping particles and the fracture wall. Our observations suggest that closure is controlled by a pressure solution-like process. The aperture of dilatant fractures and microcracks in the Earth that are similar to those in our experiments, such as ones generated from thermal stressing or brittle failure during earthquake rupture and slip, will decrease rapidly with time, especially if the macroscopic stress is nonhydrostatic.

  12. The fracture and fragmentation behaviour of additively manufactured stainless steel 316L

    NASA Astrophysics Data System (ADS)

    Amott, Russell; Harris, Ernest; Winter, Ron; Stirk, Stewart; Chapman, David; Eakins, Daniel

    2015-06-01

    Expanding cylinder experiments using a gas gun technique allow investigations into the ductility of metals and the fracture and fragmentation mechanisms that occur during rapid tensile failure. These experiments allow the radial strain-rate of the expansion to be varied in the range 102 to 104 s-1. Presented here is a comparative study of the fracture and fragmentation behaviour of rapidly expanded stainless steel 316L cylinders manufactured from either wrought bar or by additive manufacturing techniques. The results show that in the strain-rate regime studied, an additively manufactured cylinder failed at a higher strain and produced larger fragment widths compared to cylinders manufactured from wrought bar. In addition, an investigation into the role of deliberate equispaced macroscopic voids introduced into a cylinder wall has been undertaken. Using the unique properties of additive manufacture, elongated voids were introduced to the cylinder wall at an angle of 45° to the cylinder radius, and the resulting fragment patterns will be discussed. A comparison of the expanding cylinder profiles with simulations using CTH will also be presented.

  13. Open natural fractures in sandstone at 18,300 ft: Do they help or hinder production of gas?

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

    Lorenz, J.C.; Billingsley, R.L.; Evans, L.W.

    1996-06-01

    Vertical core, from relatively undeformed Cretaceous (Frontier FM) sandstones at a depth of 18,300 ft in the Green River Basin, contains three sets of mineralized natural fractures. The earliest fractures opened in extension as the strata passed through the hydrocarbon window. Continued subsidence and the maturation of organic material created overpressured conditions, causing oil to be injected into the fractures. Only a carbon residue of the original oil remains in these fractures, suggesting continued burial and maturation. The residue seriously inhibits permeability along and across fractures. Oil residue is also present in oblique, unmineralized mare`s-tails at the ends of fractures,more » suggesting that the in situ stress orientations had changed slightly. Quartz crystals mineralized the fracture walls, growing over the oil residue or pushing it aside. A second set of extension fractures strikes 20-30 degrees oblique to the first set. These fractures are mineralized with calcite, which was also deposited over the quartz in the first fracture set. Continued tectonism reoriented the horizontal stresses by nearly 90 degrees, forming a third set of extension fractures and further degrading permeability by narrowing apertures along earlier fractures. Significant porosity remains along many of the fractures at this depth, yet the in situ stresses and oil residue have combined to degrade fracture permeability to uneconomic matrix values.« less

  14. Open natural fractures in sandstone at 18,300 ft: Do they help or hinder production of gas?

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

    Lorenz, J.C.; Billingsley, R.L.; Evans, L.W.

    1995-06-01

    Vertical core, from relatively undeformed Cretaceous (Frontier Fm) sandstones at a depth of 18,300 ft in the Green River Basin, contains three sets of mineralized natural fractures. The earliest fractures opened in extension as the strata passed through the hydrocarbon window. Continued subsidence and the maturation of organic material created overpressured conditions, causing oil to be injected into the fractures. Only a carbon residue of the original oil remains in these fractures, suggesting continued burial and maturation. The residue seriously inhibits permeability along and across fractures. Oil residue is also present in oblique, unmineralized mare`s-tails at the ends of fractures,more » suggesting that the in-situ stress orientations had changed slightly. Quartz crystals mineralized the fracture walls, growing over the oil residue or pushing it aside. A second set of extension fractures strikes 20-30 degrees oblique to the first set. These fractures are mineralized with calcite, which was also deposited over the quartz in the first fracture set. Continued tectonism reoriented the horizontal stresses by nearly 90 degrees, forming a third set of extension fractures and further degrading permeability by narrowing apertures along earlier fractures. Significant porosity remains along many of the fractures at this depth, yet the in situ stresses and oil residue have combined to degrade fracture permeability to uneconomic matrix values.« less

  15. Biomechanical investigation of impact induced rib fractures of a porcine infant surrogate model.

    PubMed

    Blackburne, William B; Waddell, J Neil; Swain, Michael V; Alves de Sousa, Ricardo J; Kieser, Jules A

    2016-09-01

    This study investigated the structural, biomechanical and fractographic features of rib fractures in a piglet model, to test the hypothesis that fist impact, apart from thoracic squeezing, may result in lateral costal fractures as observed in abused infants. A mechanical fist with an accelerometer was constructed and fixed to a custom jig. Twenty stillborn piglets in the supine position were impacted on the thoracic cage. The resultant force versus time curves from the accelerometer data showed a number of steps indicative of rib fracture. The correlation between impact force and number of fractures was statistically significant (Pearson׳s r=0.528). Of the fractures visualized, 15 completely pierced the parietal pleura of the thoracic wall, and 5 had butterfly fracture patterning. Scanning electron microscopy showed complete bone fractures, at the zone of impact, were normal to the axis of the ribs. Incomplete vertical fractures, with bifurcation, occurred on the periphery of the contact zone. This work suggests the mechanism of rib failure during a fist impact is typical of the transverse fracture pattern in the anterolateral region associated with cases of non-accidental rib injury. The impact events investigated have a velocity of ~2-3m/s, approximately 2×10(4) times faster than previous quasi-static axial and bending tests. While squeezing the infantile may induce buckle fractures in the anterior as well as posterior region of the highly flexible bones, a fist punch impact event may result in anterolateral transverse fractures. Hence, these findings suggest that the presence of anterolateral rib fractures may result from impact rather than manual compression. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Orbital Debris Shape and Orientation Effects on Ballistic Limits

    NASA Technical Reports Server (NTRS)

    Evans, Steven W.; Williamsen, Joel E.

    2005-01-01

    The SPHC hydrodynamic code was used to evaluate the effects of orbital debris particle shape and orientation on penetration of a typical spacecraft dual-wall shield. Impacts were simulated at near-normal obliquity at 12 km/sec. Debris cloud characteristics and damage potential are compared with those from impacts by spherical projectiles. Results of these simulations indicate the uncertainties in the predicted ballistic limits due to modeling uncertainty and to uncertainty in the impactor orientation.

  17. Misdiagnosis of Talar Body or Neck Fractures as Ankle Sprains in Low Energy Traumas

    PubMed Central

    Young, Ki-Won; Kim, Jin-Su; Cho, Hun-Ki; Choo, Ho-Sik; Park, Jang-Ho

    2016-01-01

    Background The talus has a very complex anatomical morphology and is mainly fractured by a major force caused by a fall or a traffic accident. Therefore, a talus fracture is not common. However, many recent reports have shown that minor injuries, such as sprains and slips during sports activities, can induce a talar fracture especially in the lateral or posterior process. Still, fractures to the main parts of the talus (neck and body) after ankle sprains have not been reported as occult fractures. Methods Of the total 102 cases from January 2005 to December 2012, 7 patients had confirmed cases of missed/delayed diagnosis of a talus body or neck fracture and were included in the study population. If available, medical records, X-rays, computed tomography scans, and magnetic resonance imaging of the confirmed cases were retrospectively reviewed and analyzed. Results In the 7-patient population, there were 3 talar neck fractures and 4 talar body fractures (coronal shearing type). The mechanisms of injuries were all low energy trauma episodes. The causes of the injuries included twisting of the ankle during climbing (n = 2), jumping to the ground from a 1-m high wall (n = 2), and twisting of the ankle during daily activities (n = 3). Conclusions A talar body fracture and a talar neck fracture should be considered in the differential diagnosis of patients with acute and chronic ankle pain after a minor ankle injury. PMID:27583114

  18. Quantifying water flow and retention in an unsaturated fracture-facial domain

    USGS Publications Warehouse

    Nimmo, John R.; Malek-Mohammadi, Siamak

    2015-01-01

    Hydrologically significant flow and storage of water occur in macropores and fractures that are only partially filled. To accommodate such processes in flow models, we propose a three-domain framework. Two of the domains correspond to water flow and water storage in a fracture-facial region, in addition to the third domain of matrix water. The fracture-facial region, typically within a fraction of a millimeter of the fracture wall, includes a flowing phase whose fullness is determined by the availability and flux of preferentially flowing water, and a static storage portion whose fullness is determined by the local matric potential. The flow domain can be modeled with the source-responsive preferential flow model, and the roughness-storage domain can be modeled with capillary relations applied on the fracture-facial area. The matrix domain is treated using traditional unsaturated flow theory. We tested the model with application to the hydrology of the Chalk formation in southern England, coherently linking hydrologic information including recharge estimates, streamflow, water table fluctuation, imaging by electron microscopy, and surface roughness. The quantitative consistency of the three-domain matrix-microcavity-film model with this body of diverse data supports the hypothesized distinctions and active mechanisms of the three domains and establishes the usefulness of this framework.

  19. Hydraulic Properties of Closely Spaced Dipping Open Fractures Intersecting a Fluid-Filled Borehole Derived From Tube Wave Generation and Scattering

    NASA Astrophysics Data System (ADS)

    Minato, Shohei; Ghose, Ranajit; Tsuji, Takeshi; Ikeda, Michiharu; Onishi, Kozo

    2017-10-01

    Fluid-filled fractures and fissures often determine the pathways and volume of fluid movement. They are critically important in crustal seismology and in the exploration of geothermal and hydrocarbon reservoirs. We introduce a model for tube wave scattering and generation at dipping, parallel-wall fractures intersecting a fluid-filled borehole. A new equation reveals the interaction of tube wavefield with multiple, closely spaced fractures, showing that the fracture dip significantly affects the tube waves. Numerical modeling demonstrates the possibility of imaging these fractures using a focusing analysis. The focused traces correspond well with the known fracture density, aperture, and dip angles. Testing the method on a VSP data set obtained at a fault-damaged zone in the Median Tectonic Line, Japan, presents evidences of tube waves being generated and scattered at open fractures and thin cataclasite layers. This finding leads to a new possibility for imaging, characterizing, and monitoring in situ hydraulic properties of dipping fractures using the tube wavefield.

  20. Development of technical means for directional hydraulic fracturing with shearing loading of borehole walls

    NASA Astrophysics Data System (ADS)

    Rybalkin, LA; Patutin, AV; Patutin, DV

    2018-03-01

    During the process of mineral deposits’ mining one of the most important conditions for safe and economically profitable work of a mining enterprise is obtaining timely information on the stress state of the developed massif. One of the most common methods of remote study of the geomechanical state of the rock massif is hydraulic fracturing of the formation. Directional hydraulic fracturing is a type of the method employed to form cracks across production wells. This technology was most widely used in the gas industry to extract gas from shale formations. In mining, this technology is used to set up filtration screens, to integrate degassing, to soften the hard roof of coal seams. Possible practical appliance is the expansion of the application field of this technology to intensify the production of viscous oil, to leach non-ferrous metals, to create in the rock massif anti-filtration screens for various purposes, as well as to measure stresses acting along the wells.

  1. Using "Rebar" to Stabilize Rigid Chest Wall Reconstruction.

    PubMed

    Robinson, Lary A; Grubbs, Deanna M

    2016-04-01

    After major chest wall resection, reconstruction of the bony defect with a rigid prosthesis is mandatory to protect the underlying thoracic organs, and to prevent flail chest physiology. Although many methods have been described for chest wall reconstruction, a commonly used technique employs a composite Marlex (polypropylene) mesh with methyl-methacrylate cement sandwiched between two layers of mesh (MMS), which is tailored to the defect size and shape. In building construction, steel "rebar" is used to strengthen and reinforce masonry structures. To avoid the initial residual motion of the rigid prosthesis used to reconstruct very large defects, particularly the sternum, we devised a simple technique of adding one or more Steinmann steel pins as "rebar" to strengthen and immediately stabilize the prosthesis to the surrounding ribs and sternum. For the very large defects, particularly over the heart and great vessels, titanium mesh may also be readily added into the sandwich construction for increased strength and to prevent late prosthetic fractures. Short- and long-term results of this inexpensive modification of the MMS reconstruction technique are excellent. This modified MMS tailor-made prosthesis is only one-third the cost of the recently popular prosthetic titanium systems, takes much less operative time to create and implant, and avoids the well-described complications of late titanium bar fracture and erosion/infection as well as loosening of screws and/or titanium bars. Georg Thieme Verlag KG Stuttgart · New York.

  2. Particle Swarms in Fractures: Open Versus Partially Closed Systems

    NASA Astrophysics Data System (ADS)

    Boomsma, E.; Pyrak-Nolte, L. J.

    2014-12-01

    In the field, fractures may be isolated or connected to fluid reservoirs anywhere along the perimeter of a fracture. These boundaries affect fluid circulation, flow paths and communication with external reservoirs. The transport of drop like collections of colloidal-sized particles (particle swarms) in open and partially closed systems was studied. A uniform aperture synthetic fracture was constructed using two blocks (100 x 100 x 50 mm) of transparent acrylic placed parallel to each other. The fracture was fully submerged a tank filled with 100cSt silicone oil. Fracture apertures were varied from 5-80 mm. Partially closed systems were created by sealing the sides of the fracture with plastic film. The four boundary conditions study were: (Case 1) open, (Case 2) closed on the sides, (Case 3) closed on the bottom, and (Case 4) closed on both the sides and bottom of the fracture. A 15 μL dilute suspension of soda-lime glass particles in oil (2% by mass) were released into the fracture. Particle swarms were illuminated using a green (525 nm) LED array and imaged with a CCD camera. The presence of the additional boundaries modified the speed of the particle swarms (see figure). In Case 1, enhanced swarm transport was observed for a range of apertures, traveling faster than either very small or very large apertures. In Case 2, swarm velocities were enhanced over a larger range of fracture apertures than in any of the other cases. Case 3 shifted the enhanced transport regime to lower apertures and also reduced swarm speed when compared to Case 2. Finally, Case 4 eliminated the enhanced transport regime entirely. Communication between the fluid in the fracture and an external fluid reservoir resulted in enhanced swarm transport in Cases 1-3. The non-rigid nature of a swarm enables drag from the fracture walls to modify the swarm geometry. The particles composing a swarm reorganize in response to the fracture, elongating the swarm and maintaining its density. Unlike a

  3. Current-driven second-harmonic domain wall resonance in ferromagnetic metal/nonmagnetic metal bilayers: A field-free method for spin Hall angle measurements

    NASA Astrophysics Data System (ADS)

    Hajiali, M. R.; Hamdi, M.; Roozmeh, S. E.; Mohseni, S. M.

    2017-10-01

    We study the ac current-driven domain wall motion in bilayer ferromagnetic metal (FM)/nonmagnetic metal (NM) nanowires. The solution of the modified Landau-Lifshitz-Gilbert equation including all the spin transfer torques is used to describe motion of the domain wall in the presence of the spin Hall effect. We show that the domain wall center has a second-harmonic frequency response in addition to the known first-harmonic excitation. In contrast to the experimentally observed second-harmonic response in harmonic Hall measurements of spin-orbit torque in magnetic thin films, this second-harmonic response directly originates from spin-orbit torque driven domain wall dynamics. Based on the spin current generated by domain wall dynamics, the longitudinal spin motive force generated voltage across the length of the nanowire is determined. The second-harmonic response introduces additionally a practical field-free and all-electrical method to probe the effective spin Hall angle for FM/NM bilayer structures that could be applied in experiments. Our results also demonstrate the capability of utilizing FM/NM bilayer structures in domain wall based spin-torque signal generators and resonators.

  4. Fracture line morphology of complex proximal humeral fractures.

    PubMed

    Hasan, Afsana P; Phadnis, Joideep; Jaarsma, Ruurd L; Bain, Gregory I

    2017-10-01

    The aim of this study was to assess proximal humeral fracture patterns using 3-dimensional computed tomography images and relate them to the normal osseous landmarks and soft-tissue attachments. Forty-eight 3-dimensional computed tomography scans of proximal humeral fractures were retrospectively collected, and the fractures were transcribed onto proximal humeral templates. We analyzed the common location and orientation of the fracture lines, with a focus on fractures of the articular surface, tuberosities, metaphysis, and proximal diaphysis. These fractures were compared with the attachments of the rotator cuff and glenohumeral capsule. Fifty-two percent of the fractures involved the articular surface. No fractures passed through the bicipital groove, and fractures were more commonly found on the posterior lesser tuberosity and on the anterior greater tuberosity, coinciding with the intervals between the rotator cuff tendon insertions. Intracapsular fractures of the calcar were more common (68%) than extracapsular fractures (32%). On the anterolateral aspect of the proximal humerus, fractures radiated from the articular margin, vertically down through the tuberosity zone between the rotator cuff footprints, meeting horizontally oriented fractures in the metaphyseal zone. On the posterior aspect, vertical fractures from the tuberosity zone continued downward to the metaphyseal zone adjacent to the infraspinatus and teres minor footprints. Fractures of the proximal humerus follow characteristic patterns. Fractures frequently split the greater tuberosity and are closely related to the intervals of the rotator cuff attachments. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  5. Fracture patterns at lava-ice contacts on Kokostick Butte, OR, and Mazama Ridge, Mount Rainier, WA: Implications for flow emplacement and cooling histories

    NASA Astrophysics Data System (ADS)

    Lodge, Robert W. D.; Lescinsky, David T.

    2009-09-01

    Cooling lava commonly develop polygonal joints that form equant hexagonal columns. Such fractures are formed by thermal contraction resulting in an isotropic tensional stress regime. However, certain linear cooling fracture patterns observed at some lava-ice contacts do not appear to fit the model for formation of cooling fractures and columns because of their preferred orientations. These fracture types include sheet-like (ladder-like rectangular fracture pattern), intermediate (pseudo-aligned individual column-bounding fractures), and pseudopillow (straight to arcuate fractures with perpendicular secondary fractures caused by water infiltration) fractures that form the edges of multiple columns along a single linear fracture. Despite the relatively common occurrence of these types of fractures at lava-ice contacts, their significance and mode of formation have not been fully explored. This study investigates the stress regimes responsible for producing these unique fractures and their significance for interpreting cooling histories at lava-ice contacts. Data was collected at Kokostick Butte dacite flow at South Sister, OR, and Mazama Ridge andesite flow at Mount Rainier, WA. Both of these lava flows have been interpreted as being emplaced into contact with ice and linear fracture types have been observed on their ice-contacted margins. Two different mechanisms are proposed for the formation of linear fracture networks. One possible mechanism for the formation of linear fracture patterns is marginal bulging. Melting of confining ice walls will create voids into which flowing lava can deform resulting in margin-parallel tension causing margin-perpendicular fractures. If viewed from the ice-wall, these fractures would be steeply dipping, linear fractures. Another possible mechanism for the formation of linear fracture types is gravitational settling. Pure shear during compression and settling can result in a tensional environment with similar consequences as

  6. Influence of natural fractures on hydraulic fracture propagation

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

    Teufel, L.W.; Warpinski, N.R.

    Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principal in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found and to provide guidelines for predicting when this complex fracturing will occur.« less

  7. Influence of natural fractures on hydraulic fracture propagation

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

    Teufel, L.W.; Warpinski, N.R.

    Hydraulic fracturing has become a valuable technique for the stimulation of oil, gas, and geothermal reservoirs in a variety of reservoir rocks. In many applications, only short fractures are needed for economic production. In low-permeability reservoirs, however, long penetrating fractures are generally needed, and in this case, natural fractures can be the cause of many adverse effects during a fracture treatment. Natural fractures can influence the overall geometry and effectiveness of the hydraulic fracture by: (1) arresting the vertical or lateral growth, (2) reducing total fracture length via fluid leakoff, (3) limiting proppant transport and placement, and (4) enhancing themore » creation of multiple or secondary fractures rather than a single planar hydraulic fracture. The result may range from negligible to catastrophic depending on the values of the ancillary treatment and reservoir parameters, such as the treating pressure, in-situ stresses, pore pressure, orientations of the natural fractures relative to principle in-situ stresses, spacing and distribution of the natural fractures, permeability, etc. Field observations from mineback experiments at DOE's Nevada Test Site and the multiwell experiment in Colorado, laboratory tests, and analyses of these data are integrated to describe the complex fracture behavior found to an provide guidelines for predicting when this complex fracturing occurs.« less

  8. Deposits along the Northern Wall of Melas Chasma

    NASA Image and Video Library

    2016-10-05

    It has been known since the 1970s when the Viking orbiters took pictures of Mars that there are large (i.e., several kilometers-thick) mounds of light-toned deposits within the central portion of Valles Marineris. More recent higher resolution images of Mars, including this image of Melas Chasma, show that the wall rocks of Valles Mariners also contain similar, albeit thinner, light-toned deposits. Spectral data from the CRISM instrument indicate that the larger mounds are composed of sulfates. Some of the wall rock deposits are also made up of sulfates, but others contain clays or mixtures of several kinds of hydrated materials, suggesting that multiple aqueous processes, perhaps at different times within Valles Marineris, formed the variety of deposits we now observe. http://photojournal.jpl.nasa.gov/catalog/PIA21102

  9. A case of retained wooden foreign body in orbit.

    PubMed

    Lee, Jin A; Lee, Hae Young

    2002-12-01

    A 41-year-old man visited our clinic complaining of esodeviation of the right eye. He had been operated on for corneal laceration 3 years before. One month later, exodeviation of the right eye had developed. The result of computed tomography (CT) was reported as orbital abscess and cellulitis. Although antibiotic treatment was administered for 2 weeks, the exodeviation didn't improve. On ocular examinations performed in our hospital in November-2001, his right eye was esotropic and had a relative afferent pupillary defect. Vision of the right eye was decreased to 0.02. Fundus examination showed optic atrophy. A new CT scan disclosed a foreign body introduced into the right medial orbital wall, nasal cavity and ethmoidal sinus. Although foreign body was surgically removed, vision and eye movement were not improved. In the case of a patient who has undergone orbital trauma, complete history taking and physical examinations must be performed. On suspicion of a foreign body, imaging study such as CT or MRI must be performed. However, because CT findings can be variable, careful follow-up is needed.

  10. [Experience of systematization on the treatment of patients with upper jaws fractures, during the period 1991-2000].

    PubMed

    Khinkov, D

    2005-01-01

    A retrospecive analysis was done of the 128 patients with fractures in a upper jaw, treated during the period 1991-2000. The treatment of the patients with partial fractures in a alveolar part of maxilla and frontal wall of maxillary sinus, consist of debridement on the open wound, primery stiched and stabilization by arch bar of perspective teeth. In the cases with fractures of tuber maxilla and opening of maxillary sinus they tray to clouse it by Rhermann technique, with or without radical antrothomy by Caldwell-Luc technique. On the patients by total upper jaw fractures they try lead by princip of duble stage fixation: from one side-of intact upper bone structures and the other side-on a mandible. On the cases of upper jaw fractures, combine with barain traums. was treated conservativly - the specialize treatment of facial injures was postpoun until stabilization of brain status.

  11. On thermohydrologic conditions near high-level nuclear wastes emplaced in partially saturated fractured tuff: 1. Simulation studies with explicit consideration of fracture effects

    NASA Astrophysics Data System (ADS)

    Pruess, K.; Wang, J. S. Y.; Tsang, Y. W.

    1990-06-01

    We have performed modeling studies on the simultaneous transport of heat, liquid water, vapor, and air in partially saturated, fractured porous rock. Formation parameters were chosen as representative of the potential nuclear waste repository site in the Topopah Spring unit of the Yucca Mountain tuffs. The presence of fractures makes the transport problem very complex, both in terms of flow geometry and physics. The numerical simulator used for our flow calculations takes into account most of the physical effects believed to be important in multiphase fluid and heat flow. It has provisions for handling the extreme nonlinearities that arise in phase transitions, component disappearances, and capillary discontinuities at fracture faces. We model a region around an infinite linear string of nuclear waste canisters, taking into account both the discrete fractures and the porous matrix. Thermohydrologic conditions in the vicinity of the waste packages are found to depend strongly on relative permeability and capillary pressure characteristics of the fractures, which are unknown at the present time. If liquid held on the rough walls of drained fractures is assumed to be mobile, strong heat pipe effects are predicted. Under these conditions the host rock will remain in two-phase conditions right up to the emplacement hole, and formation temperatures will peak near 100°C. If it is assumed that liquid cannot move along drained fractures, the region surrounding the waste packages is predicted to dry up, and formation temperatures will rise beyond 200°C. A substantial fraction of waste heat can be removed if emplacement holes are left open and ventilated, as opposed to backfilled and sealed emplacement conditions. Comparing our model predictions with observations from in situ heater experiments reported by Zimmerman and coworkers, some intriguing similarities are noted. However, for a quantitative evaluation, additional carefully controlled laboratory and field experiments

  12. Micro- and macro-behaviour of fluid flow through rock fractures: an experimental study

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenyu; Nemcik, Jan; Ma, Shuqi

    2013-12-01

    Microscopic and macroscopic behaviour of fluid flow through rough-walled rock fractures was experimentally investigated. Advanced microfluidic technology was introduced to examine the microscopic viscous and inertial effects of water flow through rock fractures in the vicinity of voids under different flow velocities, while the macroscopic behaviour of fracture flow was investigated by carrying out triaxial flow tests through fractured sandstone under confining stresses ranging from 0.5 to 3.0 MPa. The flow tests show that the microscopic inertial forces increase with the flow velocity with significant effects on the local flow pattern near the voids. With the increase in flow velocity, the deviation of the flow trajectories is reduced but small eddies appear inside the cavities. The results of the macroscopic flow tests show that the linear Darcy flow occurs for mated rock fractures due to small aperture, while a nonlinear deviation of the flow occurs at relatively high Reynolds numbers in non-mated rock fracture (Re > 32). The microscopic experiments suggest that the pressure loss consumed by the eddies inside cavities could contribute to the nonlinear fluid flow behaviour through rock joints. It is found that such nonlinear flow behaviour is best matched with the quadratic-termed Forchheimer equation.

  13. Critical Appraisal on Orbital Decompression for Thyroid Eye Disease: A Systematic Review and Literature Search.

    PubMed

    Boboridis, Konstadinos G; Uddin, Jimmy; Mikropoulos, Dimitrios G; Bunce, Catey; Mangouritsas, George; Voudouragkaki, Irini C; Konstas, Anastasios G P

    2015-07-01

    Orbital decompression is the indicated procedure for addressing exophthalmos and compressive optic neuropathy in thyroid eye disease. There are an abundance of techniques for removal of orbital bone, fat, or a combination published in the scientific literature. The relative efficacy and complications of these interventions in relation to the specific indications remain as yet undocumented. We performed a systematic review of the current published evidence for the effectiveness of orbital decompression, possible complications, and impact on quality of life. We searched the current databases for medical literature and controlled trials, oculoplastic textbooks, and conference proceedings to identify relevant data up to February 2015. We included randomized controlled trials (RCTs) comparing two or more interventions for orbital decompression. We identified only two eligible RCTs for inclusion in the review. As a result of the significant variability between studies on decompression, i.e., methodology and outcome measures, we did not perform a meta-analysis. One study suggests that the transantral approach and endonasal technique had similar effects in reducing exophthalmos but the latter is safer. The second study provides evidence that intravenous steroids may be superior to primary surgical decompression in the management of compressive optic neuropathy requiring less secondary surgical procedures. Most of the published literature on orbital decompression consists of retrospective, uncontrolled trials. There is evidence from those studies that removal of the medial and lateral wall (balanced) and the deep lateral wall decompression, with or without fat removal, may be the most effective surgical methods with only few complications. There is a clear unmet need for controlled trials evaluating the different techniques for orbital decompression. Ideally, future studies should address the effectiveness, possible complications, quality of life, and cost of each

  14. Layers and Fractures in Ophir Chasma

    NASA Image and Video Library

    2015-11-05

    Ophir Chasma forms the northern portion of Valles Marineris, and this image from NASA Mars Reconnaissance Orbiter spacecraft features a small part of its wall and floor. The wall rock shows many sedimentary layers and the floor is covered with wind-blown ridges, which are intermediate in size between sand ripples and sand dunes. Rocks protruding on the floor could be volcanic intrusions of once-molten magma that have pushed aside the surrounding sedimentary layers and "froze" in place. Images like this can help geologists study the formation mechanisms of large tectonic systems like Valles Marineris. (The word "tectonics" does not mean the same thing as "plate tectonics." Tectonics simply refers to large stresses and strains in a planet's crust. Plate tectonics is the main type of tectonics that Earth has; Mars does not have plate tectonics.) http://photojournal.jpl.nasa.gov/catalog/PIA20044

  15. Orbital abscess during endodontic treatment: a case report.

    PubMed

    de Medeiros, Eduardo Henrique Pantosso; Pepato, André Oliveira; Sverzut, Cássio Edvard; Trivellato, Alexandre Elias

    2012-11-01

    Orbital infections may result in permanent morbidity because of the severity of infection. Furthermore, delayed diagnosis or treatment of orbital infections can lead to intracranial complications and even death. The majority of orbital infections develop from paranasal sinus infections, cutaneous infections, and periorbital trauma. Dacryocystitis and odontogenic infection are also accounted as potential etiologies but are scarcely reported in scientific literature. The patient revealed a history of having endodontic treatment on left maxillary second molar performed 2 weeks previously. Moreover, she exhibited signs of facial pain accompanied by sinusitis symptoms, fever, and nasal obstruction the week after this endodontic procedure. The patient presented proptosis, impairment of ocular motility to the right side, facial tenderness, palpebral erythema, and referred decreased visual acuity. Intraoral exam revealed root fragments of left maxillary first molar and an extensive carious lesion on left maxillary second molar. Computed tomography enabled the observation of frontal sinus, left-sided maxillary, opacity of sphenoidal and ethmoidal sinuses, and apical lesion of left maxillary first and second molars, all suggesting the presence of their apex in the maxillary sinus. In addition, images revealed ocular proptosis and presence of high-density areas suggestive of pus in the medial orbital wall region. The patient was submitted to surgical drainage under general anesthesia approximately 8 hours after the clinical evaluation. Early detection of orbital infection, proper diagnostic tests, and treatment may provide successful outcomes of this rarely occurring disease. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  16. Magma fracturing and degassing associated with obsidian formation: The explosive–effusive transition

    USGS Publications Warehouse

    Cabrera, Agustin; Weinberg, Roberto; Wright, Heather M.

    2015-01-01

    This paper explores the role of melt fracturing in degassing rhyolitic volcanic systems. The Monte Pilato-Rocche Rosse eruptions in Italy evolved from explosive to effusive in style, and H2O content in quenched glasses changed over time from relatively H2O-rich (~ 0.90 wt.%) to H2O-poor dense obsidian (~ 0.10–0.20 wt.%). In addition, healed fractures have been recorded in all different eruptive materials, from the glass of early-erupted tube pumice and rinds of breadcrusted obsidian pyroclasts, to the glass of late-erupted dense obsidian pyroclasts, and throughout the final effusive Rocche Rosse lava flow. These rocks show multiple fault sets, some with crenulated fault planes indicating resumption of viscous flow after faulting, complex obsidian breccias with evidence for post-brecciation folding and stretching, and centimetre- to metre-thick tuffisite preserved in pyroclasts and lava, representing collapsed foam due to fracturing of vesicle walls. These microstructural observations indicate that multiple fracturing and healing events occurred during both explosive and effusive eruptions. H2O content in glass decreases by as much as 0.14 wt.% towards healed fractures/faults and decreases in stretched obsidian breccias towards regions of intense brecciation. A drop in pressure and/or increase in temperature along fractures caused diffusive H2O migration through melt towards fracture surfaces. Repetitive and pervasive fracturing and healing thereby create conditions for diffusive H2O loss into fractures and subsequent escape through permeable paths. This type of progressive magma degassing provides a potential mechanism to explain the formation of dense obsidian and the evolution from explosive to effusive eruption style.

  17. Area balance and strain in an extensional fault system: Strategies for improved oil recovery in fractured chalk, Gilbertown Field, southwestern Alabama. Final report, March 1996--September 1998

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

    Pashin, J.C.; Raymond, D.E.; Rindsberg, A.K.

    1998-12-01

    This project was designed to analyze the structure of Mesozoic and Tertiary strata in Gilbertown Field and adjacent areas to suggest ways in which oil recovery can be improved. The Eutaw Formation comprises 7 major flow units and is dominated by low-resistivity, low-contrast play that is difficult to characterize quantitatively. Selma chalk produces strictly from fault-related fractures that were mineralized as warm fluid migrated from deep sources. Resistivity, dipmeter, and fracture identification logs corroborate that deformation is concentrated in the hanging-wall drag zones. New area balancing techniques were developed to characterize growth strata and confirm that strain is concentrated inmore » hanging-wall drag zones. Curvature analysis indicates that the faults contain numerous fault bends that influence fracture distribution. Eutaw oil is produced strictly from footwall uplifts, whereas Selma oil is produced from fault-related fractures. Clay smear and mineralization may be significant trapping mechanisms in the Eutaw Formation. The critical seal for Selma reservoirs, by contrast, is where Tertiary clay in the hanging wall is juxtaposed with poorly fractured Selma chalk in the footwall. Gilbertown Field can be revitalized by infill drilling and recompletion of existing wells. Directional drilling may be a viable technique for recovering untapped oil from Selma chalk. Revitalization is now underway, and the first new production wells since 1985 are being drilled in the western part of the field.« less

  18. Correlation of Hip Fracture with Other Fracture Types: Toward a Rational Composite Hip Fracture Endpoint

    PubMed Central

    Colón-Emeric, Cathleen; Pieper, Carl F.; Grubber, Janet; Van Scoyoc, Lynn; Schnell, Merritt L; Van Houtven, Courtney Harold; Pearson, Megan; Lafleur, Joanne; Lyles, Kenneth W.; Adler, Robert A.

    2016-01-01

    Purpose With ethical requirements to the enrollment of lower risk subjects, osteoporosis trials are underpowered to detect reduction in hip fractures. Different skeletal sites have different levels of fracture risk and response to treatment. We sought to identify fracture sites which cluster with hip fracture at higher than expected frequency; if these sites respond to treatment similarly, then a composite fracture endpoint could provide a better estimate of hip fracture reduction. Methods Cohort study using Veterans Affairs and Medicare administrative data. Male Veterans (n=5,036,536) aged 50-99 years receiving VA primary care between1999-2009 were included. Fractures were ascertained using ICD9 and CPT codes and classified by skeletal site. Pearson correlation coefficients, logistic regression and kappa statistics, were used to describe the correlation between each fracture type and hip fracture within individuals, without regards to the timing of the events. Results 595,579 (11.8%) men suffered 1 or more fractures and 179,597 (3.6%) suffered 2 or more fractures during the time under study. Of those with one or more fractures, rib was the most common site (29%), followed by spine (22%), hip (21%) and femur (20%). The fracture types most highly correlated with hip fracture were pelvic/acetabular (Pearson correlation coefficient 0.25, p<0.0001), femur (0.15, p<0.0001), and shoulder (0.11, p<0.0001). Conclusions Pelvic, acetabular, femur, and shoulder fractures cluster with hip fractures within individuals at greater than expected frequency. If we observe similar treatment risk reductions within that cluster, subsequent trials could consider use of a composite endpoint to better estimate hip fracture risk. PMID:26151123

  19. Prospective clinical trial of surgical intervention for painful rib fracture nonunion.

    PubMed

    Fabricant, Loic; Ham, Bruce; Mullins, Richard; Mayberry, John

    2014-06-01

    We performed a prospective clinical trial of resection with or without plate fixation for symptomatic rib fracture nonunion three or more months postinjury with 6-month postoperative followup. The McGill Pain Questionnaire (MPQ) and RAND 36 Health Survey were administered and activity level (sedentary, ambulatory, moderately active, vigorous), functional status (disabled, nonphysical labor, physical labor), and work status (employed, unemployed, retired, student) were queried pre- and postoperatively. Twenty-four patients 4 to 197 months (median, 16 months) postinjury underwent surgical intervention for one to four rib fracture nonunions (median, two nonunions). Evidence of intercostal nerve entrapment was present in nine patients (38%). MPQ Present Pain Intensity and Pain Rating Index and RAND 36 Physical Functioning, Role Physical, Social Functioning, Role Social, Bodily Pain, Vitality, Mental Health, and General Health were significantly improved at six months compared with study entry (P < 0.05). Activity levels significantly improved (P < 0.0001) but functional and work status did not change. Twenty-four-hour morphine equivalent dosage of opioids at study entry was 20.3 ± 30.8 (mean ± standard deviation) and at study completion was 9.4 ± 17.5 (P = 0.054). Complications included one wound infection, two partial screw backouts, and one chest wall hernia at one year after resection of adjacent nonunions with significant gaps repaired with absorbable plates. Surgical intervention for rib fracture nonunion may improve chronic pain and disability but without change in functional or work status. Resection of adjacent nonunions with significant gaps may lead to chest wall hernia.

  20. A fully-neoclassical finite-orbit-width version of the CQL3D Fokker–Planck code

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

    Petrov, Yu V.; Harvey, R. W.

    The time-dependent bounce-averaged CQL3D flux-conservative finite-difference Fokker–Planck equation (FPE) solver has been upgraded to include finite-orbit-width (FOW) capabilities which are necessary for an accurate description of neoclassical transport, losses to the walls, and transfer of particles, momentum, and heat to the scrape-off layer. The FOW modifications are implemented in the formulation of the neutral beam source, collision operator, RF quasilinear diffusion operator, and in synthetic particle diagnostics. The collisional neoclassical radial transport appears naturally in the FOW version due to the orbit-averaging of local collision coefficients coupled with transformation coefficients from local (R, Z) coordinates along each guiding-center orbit tomore » the corresponding midplane computational coordinates, where the FPE is solved. In a similar way, the local quasilinear RF diffusion terms give rise to additional radial transport of orbits. We note that the neoclassical results are obtained for ‘full’ orbits, not dependent on a common small orbit-width approximation. Results of validation tests for the FOW version are also presented.« less

  1. A fully-neoclassical finite-orbit-width version of the CQL3D Fokker–Planck code

    DOE PAGES

    Petrov, Yu V.; Harvey, R. W.

    2016-09-08

    The time-dependent bounce-averaged CQL3D flux-conservative finite-difference Fokker–Planck equation (FPE) solver has been upgraded to include finite-orbit-width (FOW) capabilities which are necessary for an accurate description of neoclassical transport, losses to the walls, and transfer of particles, momentum, and heat to the scrape-off layer. The FOW modifications are implemented in the formulation of the neutral beam source, collision operator, RF quasilinear diffusion operator, and in synthetic particle diagnostics. The collisional neoclassical radial transport appears naturally in the FOW version due to the orbit-averaging of local collision coefficients coupled with transformation coefficients from local (R, Z) coordinates along each guiding-center orbit tomore » the corresponding midplane computational coordinates, where the FPE is solved. In a similar way, the local quasilinear RF diffusion terms give rise to additional radial transport of orbits. We note that the neoclassical results are obtained for ‘full’ orbits, not dependent on a common small orbit-width approximation. Results of validation tests for the FOW version are also presented.« less

  2. Radiologic Parameters of Orbital Bone Remodeling in Thyroid Eye Disease.

    PubMed

    Tan, Nicholas Y Q; Leong, Yuan-Yuh; Lang, Stephanie S; Htoon, Zin M; Young, Stephanie M; Sundar, Gangadhara

    2017-05-01

    To radiologically examine for the presence of bony remodeling of the orbit in thyroid eye disease (TED). Computed tomography (CT) scans of 248 orbits of 124 patients with TED and 185 orbits of 138 controls were retrospectively reviewed, and the following parameters measured: the angle of the inferomedial orbital strut (AIOS), the angle of the medial wall (AMW), and the diameters of the extraocular muscles. The association of TED with the AIOS or AMW was analyzed with linear regression models, and the correlations between the AMW or AIOS measurements with the extraocular muscle measurements were determined. Overall, the AIOS was found to be larger (P < 0.001) and the AMW smaller (P = 0.045) in patients with TED compared to controls. After adjusting for age and sex, the larger AIOS in TED remained significant (P < 0.001), but the smaller AMW in TED patients was no longer significant (P = 0.07). There was a negative correlation between AMW and the calculated average cross-sectional area of the medial rectus in TED (r = -0.23, P = 0.01). A difference in the structure of the bony orbit in TED compared to controls may be demonstrated by the AIOS and AMW radiological parameters. This likely represents the presence of bony remodeling in TED, which may be related to the expansion of the intraorbital soft tissue volume.

  3. Antibiotics and Facial Fractures: Evidence-Based Recommendations Compared with Experience-Based Practice

    PubMed Central

    Mundinger, Gerhard S.; Borsuk, Daniel E.; Okhah, Zachary; Christy, Michael R.; Bojovic, Branko; Dorafshar, Amir H.; Rodriguez, Eduardo D.

    2014-01-01

    Efficacy of prophylactic antibiotics in craniofacial fracture management is controversial. The purpose of this study was to compare evidence-based literature recommendations regarding antibiotic prophylaxis in facial fracture management with expert-based practice. A systematic review of the literature was performed to identify published studies evaluating pre-, peri-, and postoperative efficacy of antibiotics in facial fracture management by facial third. Study level of evidence was assessed according to the American Society of Plastic Surgery criteria, and graded practice recommendations were made based on these assessments. Expert opinions were garnered during the Advanced Orbital Surgery Symposium in the form of surveys evaluating senior surgeon clinical antibiotic prescribing practices by time point and facial third. A total of 44 studies addressing antibiotic prophylaxis and facial fracture management were identified. Overall, studies were of poor quality, precluding formal quantitative analysis. Studies supported the use of perioperative antibiotics in all facial thirds, and preoperative antibiotics in comminuted mandible fractures. Postoperative antibiotics were not supported in any facial third. Survey respondents (n = 17) cumulatively reported their antibiotic prescribing practices over 286 practice years and 24,012 facial fracture cases. Percentages of prescribers administering pre-, intra-, and postoperative antibiotics, respectively, by facial third were as follows: upper face 47.1, 94.1, 70.6; midface 47.1, 100, 70.6%; and mandible 68.8, 94.1, 64.7%. Preoperative but not postoperative antibiotic use is recommended for comminuted mandible fractures. Frequent use of pre- and postoperative antibiotics in upper and midface fractures is not supported by literature recommendations, but with low-level evidence. Higher level studies may better guide clinical antibiotic prescribing practices. PMID:25709755

  4. Multiwell fracturing experiments. [Nitrogen foam fracture treatment

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

    Warpinski, N.

    The objective of the Multiwell fracturing experiments is to test and develop the technology for the efficient stimulation of tight, lenticular gas sands. This requires basic understanding of: (1) fracture behavior and geometry in this complex lithologic environment, and (2) subsequent production into the created fracture. The intricate interplay of the hydraulic fracture with the lens geometry, the internal reservoir characteristics (fractures, reservoir breaks, etc.), the in situ stresses, and the mechanical defects (fracture, bedding, etc.) need to be defined in order to develop a successful stimulation program. The stimulation phase of the Multiwell Experiment is concerned with: (1) determiningmore » important rock/reservoir properties that influence or control fracture geometry and behavior, (2) designing fracture treatments to achieve a desired size and objectives, and (3) conducting post-treatment analyses to evaluate the effectiveness of the treatment. Background statement, project description, results and evaluation of future plans are presented. 5 refs., 2 figs., 2 tabs.« less

  5. Periosteal infusion of bupivacaine/morphine post sternal fracture: a new analgesic technique.

    PubMed

    Duncan, Michael A; McNicholas, Walter; O'Keeffe, Declan; O'Reilly, Maeve

    2002-01-01

    Sternal fracture pain is severe and is difficult to alleviate due to the forces acting on the chest wall during respiration. We describe a continuous infusion regional analgesic technique for pain due to sternal fracture. A 47-year-old woman presented with a spontaneous sternal fracture, precluding effective coughing. Diclofenac and increasing doses of opioids did not give adequate pain relief and led to opioid toxicity. Two brief periods of analgesia were achieved with deep subcutaneous infiltration of bupivacaine. An epidural catheter was positioned periosteally, and an infusion of bupivacaine was commenced at 5 mL/h, achieving long-lasting analgesia. The bupivacaine concentration was reduced in a stepwise fashion from 0.5% to 0.25% and was changed to levobupivacaine after 3 days. Adding morphine (5 mg/60 mL levobupivicaine) permitted a reduction in infusion rate. The catheter was removed after 14 days because a local infection developed that resolved uneventfully with antibiotic therapy. Continuous infusion of local anesthetic and opioid to a sternal fracture site using a periosteally positioned catheter led to successful analgesia and hence improved respiratory function. Clinicians should consider placing a periosteal catheter when pain associated with sternal fracture cannot be adequately controlled with conventional methods.

  6. Foal Fractures: Osteochondral Fragmentation, Proximal Sesamoid Bone Fractures/Sesamoiditis, and Distal Phalanx Fractures.

    PubMed

    Reesink, Heidi L

    2017-08-01

    Foals are susceptible to many of the same types of fractures as adult horses, often secondary to external sources of trauma. In addition, some types of fractures are specific to foals and occur routinely in horses under 1 year of age. These foal-specific fractures may be due to the unique musculoskeletal properties of the developing animal and may present with distinct clinical signs. Treatment plans and prognoses are tailored specifically to young animals. Common fractures not affecting the long bones in foals are discussed in this article, including osteochondral fragmentation, proximal sesamoid bone fractures/sesamoiditis, and distal phalanx fractures. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Comparison of the fracture resistance of dental implants with different abutment taper angles.

    PubMed

    Wang, Kun; Geng, Jianping; Jones, David; Xu, Wei

    2016-06-01

    To investigate the effects of abutment taper angles on the fracture strength of dental implants with TIS (taper integrated screwed-in) connection. Thirty prototype cylindrical titanium alloy 5.0mm-diameter dental implants with different TIS-connection designs were divided into six groups and tested for their fracture strength, using a universal testing machine. These groups consisted of combinations of 3.5 and 4.0 mm abutment diameter, each with taper angles of 6°, 8° or 10°. 3-Dimensional finite element analysis (FEA) was also used to analyze stress states at implant-abutment connection areas. In general, the mechanical tests found an increasing trend of implant fracture forces as the taper angle enlarged. When the abutment diameter was 3.5 mm, the mean fracture forces for 8° and 10° taper groups were 1638.9 N ± 20.3 and 1577.1 N ± 103.2, respectively, both larger than that for the 6° taper group of 1475.0 N ± 24.4, with the largest increasing rate of 11.1%. Furthermore, the difference between 8° and 6° taper groups was significant, based on Tamhane's multiple comparison test (P<0.05). In 4.0 mm-diameter abutment groups, as the taper angle was enlarged from 6° to 8° and 10°, the mean fracture value was increased from 1066.7 N ± 56.1 to 1241.4 N ± 6.4 and 1419.3 N ± 20.0, with the largest increasing rate of 33.1%, and the differences among the three groups were significant (P<0.05). The FEA results showed that stress values varied in implants with different abutment taper angles and supported the findings of the static tests. In conclusion, increases of the abutment taper angle could significantly increase implant fracture resistance in most cases established in the study, which is due to the increased implant wall thickness in the connection part resulting from the taper angle enlargement. The increasing effects were notable when a thin implant wall was present to accommodate wide abutments. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Effective load transfer by a chromium carbide nanostructure in a multi-walled carbon nanotube/copper matrix composite

    NASA Astrophysics Data System (ADS)

    Cho, Seungchan; Kikuchi, Keiko; Kawasaki, Akira; Kwon, Hansang; Kim, Yangdo

    2012-08-01

    Multi-walled carbon nanotube (MWCNT) reinforced copper (Cu) matrix composites, which exhibit chromium (Cr) carbide nanostructures at the MWCNT/Cu interface, were prepared through a carbide formation using CuCr alloy powder. The fully densified and oriented MWCNTs dispersed throughout the composites were prepared using spark plasma sintering (SPS) followed by hot extrusion. The tensile strengths of the MWCNT/CuCr composites increased with increasing MWCNTs content, while the tensile strength of MWCNT/Cu composite decreased from that of monolithic Cu. The enhanced tensile strength of the MWCNT/CuCr composites is a result of possible load-transfer mechanisms of the interfacial Cr carbide nanostructures. The multi-wall failure of MWCNTs observed in the fracture surface of the MWCNT/CuCr composites indicates an improvement in the load-bearing capacity of the MWCNTs. This result shows that the Cr carbide nanostructures effectively transferred the tensile load to the MWCNTs during fracture through carbide nanostructure formation in the MWCNT/Cu composite.

  9. Heterogeneous alternation of fractured rock driven by preferential carbonate dissolution

    NASA Astrophysics Data System (ADS)

    Wen, H.; Zhi, W.; Li, L.

    2016-12-01

    Understanding the alternation of fractured rock induced by geochemical reactions is critical for predicting the flow, solute transport and energy production in geosystems. Most existing studies on fracture alterations focus on rocks with single minerals where reactions occur at the fracture wall resulting in fracture aperture alteration while ignoring rock matrix properties (e.g. the formation and development of altered zones). In this work, we aimed to mechanistically understand the role of preferential calcite dissolution in the long-term evolution of fracture and rock matrix. We use direct simulation of physics-based reactive transport processes in an image of fractured rock at the resolution of tens of micrometers. Three numerical experiments were carried out with the same initial physical properties however different calcite content. Simulation results show that the formation and development of altered zones in the rock matrix is highly related to the abundance of fast-dissolving calcite. Abundant calcite (50% (v/v), calcite50) leads to a localized, thick zone of large porosity increase while low calcite content (10% (v/v), calcite10) creates an extended and narrow zone of small porosity increase resulting in surprisingly larger change in effective transport property. After 300 days of dissolution, although with relatively similar dissolved calcite mass and matrix porosity increase, effective matrix diffusion coefficients increase by 9.9 and 19.6 times in calcite50 and calcite10, respectively. In turn, calcite dissolution rates are directly limited by diffusive transport in the altered matrix and the shape of the altered zone. This work sheds light on the unique characteristics of reactive transport in fractured, mineralogically complex rocks that are different from those with single minerals (Wen et al., 2016). Reference: Wen, H., Li, L., Crandall, D. and Hakala, J.A. (2016) Where Lower Calcite Abundance Creates More Alteration: Enhanced Rock Matrix

  10. Effect of Orbital Decompression on Corneal Topography in Patients with Thyroid Ophthalmopathy

    PubMed Central

    Kim, Su Ah; Jung, Su Kyung; Paik, Ji Sun; Yang, Suk-Woo

    2015-01-01

    Objective To evaluate changes in corneal astigmatism in patients undergoing orbital decompression surgery. Methods This retrospective, non randomized comparative study involved 42 eyes from 21 patients with thyroid ophthalmopathy who underwent orbital decompression surgery between September 2011 and September 2014. The 42 eyes were divided into three groups: control (9 eyes), two-wall decompression (25 eyes), and three-wall decompression (8 eyes). The control group was defined as the contralateral eyes of nine patients who underwent orbital decompression surgery in only one eye. Corneal topography (Orbscan II), Hertel exophthalmometry, and intraocular pressure were measured at 1 month before and 3 months after surgery. Corneal topographic parameters analyzed were total astigmatism (TA), steepest axis (SA), central corneal thickness (CCT), and anterior chamber depth (ACD). Results Exophthalmometry values and intraocular pressure decreased significantly after the decompression surgery. The change (absolute value (|x|) of the difference) in astigmatism at the 3 mm zone was significantly different between the decompression group and the controls (p = 0.025). There was also a significant change in the steepest axis at the 3 mm zone between the decompression group and the controls (p = 0.033). An analysis of relevant changes in astigmatism showed that there was a dominant tendency for incyclotorsion of the steepest axis in eyes that underwent decompression surgery. Using Astig PLOT, the mean surgically induced astigmatism (SIA) was 0.21±0.88 D with an axis of 46±22°, suggesting that decompression surgery did change the corneal shape and induced incyclotorsion of the steepest axis. Conclusions There was a significant change in corneal astigmatism after orbital decompression surgery and this change was sufficient to affect the optical function of the cornea. Surgeons and patients should be aware of these changes. PMID:26352432

  11. An analytical solution for transient flow of Bingham viscoplastic materials in rock fractures

    USGS Publications Warehouse

    Amadei, B.; Savage, W.Z.

    2001-01-01

    We present below an analytical solution to model the one-dimensional transient flow of a Bingham viscoplastic material in a fracture with parallel walls (smooth or rough) that is subjected to an applied pressure gradient. The solution models the acceleration and the deceleration of the material as the pressure gradient changes with time. Two cases are considered: A pressure gradient applied over a finite time interval and an applied pressure gradient that is constant over time. The solution is expressed in dimensionless form and can therefore be used for a wide range of Bingham viscoplastic materials. The solution is also capable of capturing the transition that takes place in a fracture between viscoplastic flow and rigid plug flow. Also, it shows the development of a rigid central layer in fractures, the extent of which depends on the fluid properties (viscosity and yield stress), the magnitude of the pressure gradient, and the fracture aperture and surface roughness. Finally, it is shown that when a pressure gradient is applied and kept constant, the solution for the fracture flow rate converges over time to a steady-state solution that can be defined as a modified cubic law. In this case, the fracture transmissivity is found to be a non-linear function of the head gradient. This solution provides a tool for a better understanding of the flow of Bingham materials in rock fractures, interfaces, and cracks. ?? 2001 Elsevier Science Ltd. All rights reserved.

  12. Surface Evolution from Orbital Decay on Phobos

    NASA Astrophysics Data System (ADS)

    Hurford, Terry; Asphaug, Erik; Spitale, Joseph; Hemingway, Douglas; Rhoden, Alyssa; Henning, Wade; Bills, Bruce; Kattenhorn, Simon; Walker, Matthew

    2015-11-01

    Phobos, the innermost satellite of Mars, displays an extensive system of grooves that are mostly symmetric about its sub-Mars point. Phobos is steadily spiraling inward due to the tides it raises, and will suffer tidal disruption before colliding with Mars. We calculate the surface stress field of the de-orbiting satellite and show that the first signs of tidal disruption are already present on its surface. Most of Phobos’ prominent grooves have an excellent correlation with computed stress orientations. The model predicts an interior that has very low strength on the tidal evolution timescale, overlain by a ~10-100 m exterior shell that has elastic properties similar to lunar regolith.Shortly after the Viking spacecraft obtained the first geomorphic images of Phobos, it was proposed that stresses from orbital decay cause grooves. But, assuming a homogeneous Phobos, it proved impossible to account for the build-up of failure stress in the exterior regardless of the value assumed for Phobos’ rigidity. Hence, the tidal model languished. Here, we revisit the tidal origin of surface fractures with a more detailed treatment that shows the production of significant stress in a surface layer, with a very strong correlation to the geometry of grooves.Our model results applied to surface observations imply that Phobos has a rubble pile interior that is nearly strengthless. A lunar-like cohesive regolith outer layer overlays the rubble pile interior. This outer layer behaves elastically and can experience significant tidal stress at levels able to drive tensile failure. Fissures can develop as the global body deforms due to increasing tides related to orbital decay. Phobos may have an active and evolving surface; an exciting target for further exploration. The interior predictions of this model can be evaluated by future detailed studies performed by an orbiter or lander.

  13. Influence of diameter on particle transport in a fractured shale saprolite

    USGS Publications Warehouse

    Cumbie, D.H.; McKay, L.D.

    1999-01-01

    Experiments in an undisturbed, saturated column of weathered and fractured shale saprolite using fluorescent carboxylate-coated latex microspheres as tracers indicate that particle diameter plays a major role in controlling transport. In this study the optimum microsphere diameter for transport was approximately 0.5 ??m. Microspheres larger than the optimum size were present in the effluent at lower relative concentrations, apparently because of greater retention due to gravitational settling and/or physical straining. The smaller than optimum microspheres also experienced greater retention, apparently related to their higher rates of diffusion. Faster diffusion can lead to more frequent collisions with, and attachment to, fracture walls and may also lead to movement of particles into zones of relatively immobile pore water in the fractures or in the fine pore structure of the clay-rich matrix between fractures. Dismantling of the soil column and mapping of the distribution of retained microspheres indicated that there was substantial size-segregation of the microspheres between different fractures or in 'channels' within a fracture. Examination of small core samples showed that the smallest microspheres (0.05-0.1 ??m) were present in the fine pores of the matrix at distances of up to 3-4 mm from the nearest fracture, which supports the hypothesis that small particles can be retained by diffusion into the matrix. Calculations of settling velocity and diffusion rate using simple 1D approaches suggest that these processes could both cause significant retention of the larger and smaller particles, respectively, even for the fast advective transport rates (up to 32 m/day) observed during the experiments. Copyright (C) 1999 Elsevier Science B.V.

  14. Successful Surgical Stabilization of Rib Fractures Despite Candida Colonization of the Mediastinum.

    PubMed

    Ju, Tammy; Rivas, Lisbi; Sarani, Babak

    2018-04-06

    Pleural space or chest wall infection is a contraindication for surgical stabilization of rib fractures (SSRF) due to the risk of hardware infection. However, the exact degree of risk is uncertain. SSRF is associated with decreased need for mechanical ventilation and pneumonia. Here, we describe a poly-trauma patient with candida colonization of the mediastinum who successfully underwent SSRF. Copyright © 2018. Published by Elsevier Inc.

  15. orbit-estimation: Fast orbital parameters estimator

    NASA Astrophysics Data System (ADS)

    Mackereth, J. Ted; Bovy, Jo

    2018-04-01

    orbit-estimation tests and evaluates the Stäckel approximation method for estimating orbit parameters in galactic potentials. It relies on the approximation of the Galactic potential as a Stäckel potential, in a prolate confocal coordinate system, under which the vertical and horizontal motions decouple. By solving the Hamilton Jacobi equations at the turning points of the horizontal and vertical motions, it is possible to determine the spatial boundary of the orbit, and hence calculate the desired orbit parameters.

  16. A comparison of spacecraft penetration hazards due to meteoroids and manmade earth-orbiting objects

    NASA Technical Reports Server (NTRS)

    Brooks, D. R.

    1976-01-01

    The ability of a typical double-walled spacecraft structure to protect against penetration by high-velocity incident objects is reviewed. The hazards presented by meteoroids are compared to the current and potential hazards due to manmade orbiting objects. It is shown that the nature of the meteoroid number-mass relationship makes adequate protection for large space facilities a conceptually straightforward structural problem. The present level of manmade orbiting objects (an estimated 10,000 in early 1975) does not pose an unacceptable risk to manned space operations proposed for the near future, but it does produce penetration probabilities in the range of 1-10 percent for a 100-m diameter sphere in orbit for 1,000 days. The number-size distribution of manmade objects is such that adequate protection is difficult to achieve for large permanent space facilities, to the extent that future restrictions on such facilities may result if the growth of orbiting objects continues at its historical rate.

  17. The Hot Orbit: Orbital Cellulitis

    PubMed Central

    Chaudhry, Imtiaz A.; Al-Rashed, Waleed; Arat, Yonca O.

    2012-01-01

    Orbital cellulitis is an uncommon condition previously associated with severe complications. If untreated, orbital cellulitis can be potentially sight and life threatening. It can affect both adults and children but has a greater tendency to occur in the pediatric age group. The infection most commonly originates from sinuses, eyelids or face, retained foreign bodies, or distant soources by hematogenous spread. It is characterized by eyelid edema, erythema, chemosis, proptosis, blurred vision, fever, headache, and double vision. A history of upper respiratory tract infection prior to the onset is very common especially in children. In the era prior to antibiotics, vision loss from orbital cellulitis was a dreaded complication. Currently, imaging studies for detection of orbital abcess, the use of antibiotics and early drainage have mitigated visual morbidity significantly. The purpose of this review is to describe current investigative strategies and management options in the treatment of orbital cellulitis, establish their effectiveness and possible complications due to late intervention. PMID:22346113

  18. Tectonics of ridge-transform intersections at the Kane fracture zone

    NASA Astrophysics Data System (ADS)

    Karson, J. A.; Dick, H. J. B.

    1983-03-01

    The Kane Transform offsets spreading-center segments of the Mid-Atlantic Ridge by about 150 km at 24° N latitude. In terms of its first-order morphological, geological, and geophysical characteristics it appears to be typical of long-offset (>100 km), slow-slipping (2 cm yr-1) ridge-ridge transform faults. High-resolution geological observations were made from deep-towed ANGUS photographs and the manned submersible ALVIN at the ridge-transform intersections and indicate similar relationships in these two regions. These data indicate that over a distance of about 20 km as the spreading axes approach the fracture zone, the two flanks of each ridge axis behave in very different ways. Along the flanks that intersect the active transform zone the rift valley floor deepens and the surface expression of volcanism becomes increasingly narrow and eventually absent at the intersection where only a sediment-covered ‘nodal basin’ exists. The adjacent median valley walls have structural trends that are oblique to both the ridge and the transform and have as much as 4 km of relief. These are tectonically active regions that have only a thin (<200 m), highly fractured, and discontinuous carapace of volcanic rocks overlying a variably deformed and metamorphosed assemblage of gabbroic rocks. Overprinting relationships reveal a complex history of crustal extension and rapid vertical uplift. In contrast, the opposing flanks of the ridge axes, that intersect the non-transform zones appear to be similar in many respects to those examined elsewhere along slow-spreading ridges. In general, a near-axial horst and graben terrain floored by relatively young volcanics passes laterally into median valley walls with a simple block-faulted character where only volcanic rocks have been found. Along strike toward the fracture zone, the youngest volcanics form linear constructional volcanic ridges that transect the entire width of the fracture zone valley. These volcanics are continuous with

  19. Lunar Reconnaissance Orbiter Orbit Determination Accuracy Analysis

    NASA Technical Reports Server (NTRS)

    Slojkowski, Steven E.

    2014-01-01

    Results from operational OD produced by the NASA Goddard Flight Dynamics Facility for the LRO nominal and extended mission are presented. During the LRO nominal mission, when LRO flew in a low circular orbit, orbit determination requirements were met nearly 100% of the time. When the extended mission began, LRO returned to a more elliptical frozen orbit where gravity and other modeling errors caused numerous violations of mission accuracy requirements. Prediction accuracy is particularly challenged during periods when LRO is in full-Sun. A series of improvements to LRO orbit determination are presented, including implementation of new lunar gravity models, improved spacecraft solar radiation pressure modeling using a dynamic multi-plate area model, a shorter orbit determination arc length, and a constrained plane method for estimation. The analysis presented in this paper shows that updated lunar gravity models improved accuracy in the frozen orbit, and a multiplate dynamic area model improves prediction accuracy during full-Sun orbit periods. Implementation of a 36-hour tracking data arc and plane constraints during edge-on orbit geometry also provide benefits. A comparison of the operational solutions to precision orbit determination solutions shows agreement on a 100- to 250-meter level in definitive accuracy.

  20. Insights about transport mechanisms and fracture flow channeling from multi-scale observations of tracer dispersion in shallow fractured crystalline rock.

    PubMed

    Guihéneuf, N; Bour, O; Boisson, A; Le Borgne, T; Becker, M W; Nigon, B; Wajiduddin, M; Ahmed, S; Maréchal, J-C

    2017-11-01

    In fractured media, solute transport is controlled by advection in open and connected fractures and by matrix diffusion that may be enhanced by chemical weathering of the fracture walls. These phenomena may lead to non-Fickian dispersion characterized by early tracer arrival time, late-time tailing on the breakthrough curves and potential scale effect on transport processes. Here we investigate the scale dependency of these processes by analyzing a series of convergent and push-pull tracer experiments with distance of investigation ranging from 4m to 41m in shallow fractured granite. The small and intermediate distances convergent experiments display a non-Fickian tailing, characterized by a -2 power law slope. However, the largest distance experiment does not display a clear power law behavior and indicates possibly two main pathways. The push-pull experiments show breakthrough curve tailing decreases as the volume of investigation increases, with a power law slope ranging from -3 to -2.3 from the smallest to the largest volume. The multipath model developed by Becker and Shapiro (2003) is used here to evaluate the hypothesis of the independence of flow pathways. The multipath model is found to explain the convergent data, when increasing local dispersivity and reducing the number of pathways with distance which suggest a transition from non-Fickian to Fickian transport at fracture scale. However, this model predicts an increase of tailing with push-pull distance, while the experiments show the opposite trend. This inconsistency may suggest the activation of cross channel mass transfer at larger volume of investigation, which leads to non-reversible heterogeneous advection with scale. This transition from independent channels to connected channels when the volume of investigation increases suggest that both convergent and push-pull breakthrough curves can inform the existence of characteristic length scales. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Insights about transport mechanisms and fracture flow channeling from multi-scale observations of tracer dispersion in shallow fractured crystalline rock

    NASA Astrophysics Data System (ADS)

    Guihéneuf, N.; Bour, O.; Boisson, A.; Le Borgne, T.; Becker, M. W.; Nigon, B.; Wajiduddin, M.; Ahmed, S.; Maréchal, J.-C.

    2017-11-01

    In fractured media, solute transport is controlled by advection in open and connected fractures and by matrix diffusion that may be enhanced by chemical weathering of the fracture walls. These phenomena may lead to non-Fickian dispersion characterized by early tracer arrival time, late-time tailing on the breakthrough curves and potential scale effect on transport processes. Here we investigate the scale dependency of these processes by analyzing a series of convergent and push-pull tracer experiments with distance of investigation ranging from 4 m to 41 m in shallow fractured granite. The small and intermediate distances convergent experiments display a non-Fickian tailing, characterized by a -2 power law slope. However, the largest distance experiment does not display a clear power law behavior and indicates possibly two main pathways. The push-pull experiments show breakthrough curve tailing decreases as the volume of investigation increases, with a power law slope ranging from - 3 to - 2.3 from the smallest to the largest volume. The multipath model developed by Becker and Shapiro (2003) is used here to evaluate the hypothesis of the independence of flow pathways. The multipath model is found to explain the convergent data, when increasing local dispersivity and reducing the number of pathways with distance which suggest a transition from non-Fickian to Fickian transport at fracture scale. However, this model predicts an increase of tailing with push-pull distance, while the experiments show the opposite trend. This inconsistency may suggest the activation of cross channel mass transfer at larger volume of investigation, which leads to non-reversible heterogeneous advection with scale. This transition from independent channels to connected channels when the volume of investigation increases suggest that both convergent and push-pull breakthrough curves can inform the existence of characteristic length scales.

  2. Accurate computation and continuation of homoclinic and heteroclinic orbits for singular perturbation problems

    NASA Technical Reports Server (NTRS)

    Vaughan, William W.; Friedman, Mark J.; Monteiro, Anand C.

    1993-01-01

    In earlier papers, Doedel and the authors have developed a numerical method and derived error estimates for the computation of branches of heteroclinic orbits for a system of autonomous ordinary differential equations in R(exp n). The idea of the method is to reduce a boundary value problem on the real line to a boundary value problem on a finite interval by using a local (linear or higher order) approximation of the stable and unstable manifolds. A practical limitation for the computation of homoclinic and heteroclinic orbits has been the difficulty in obtaining starting orbits. Typically these were obtained from a closed form solution or via a homotopy from a known solution. Here we consider extensions of our algorithm which allow us to obtain starting orbits on the continuation branch in a more systematic way as well as make the continuation algorithm more flexible. In applications, we use the continuation software package AUTO in combination with some initial value software. The examples considered include computation of homoclinic orbits in a singular perturbation problem and in a turbulent fluid boundary layer in the wall region problem.

  3. [Operative treatment of displaced intra-articular calcaneal fractures].

    PubMed

    Zwipp, H; Rammelt, S; Amlang, M; Pompach, M; Dürr, C

    2013-12-01

    Anatomic reduction of displaced intra-articular calcaneal fractures with restoration of height, length, and axial alignment and reconstruction of the subtalar and calcaneocuboid joints. Displaced intra-articular calcaneal fractures with incongruity of the posterior facet of the subtalar joint, loss of height, and axial malalignment. High perioperative risk, soft tissue infection, advanced peripheral arterial disease (stage III), neurogenic osteoarthropathy, poor patient compliance (e. g., substance abuse). Extended lateral approach with the patient placed on the uninjured side. Reduction of the anatomic shape and joint surfaces according to the preoperative CT-based planning. Reduction of the medial wall and step-wise reconstruction of the posterior facet from medial to lateral. Reduction of the tuberosity and anterior process fragments to the posterior joint block and temporary fixation with Kirschner wires. Internal fixation with an anatomic lateral plate in a locking or nonlocking mode. Alternatively less invasive internal fixation with a calcaneus nail over a sinus tarsi approach for less severe fracture types. The lower leg is immobilized in a brace until the wound is healed. Range of motion exercises of the ankle and subtalar joints are initiated on the second postoperative day. Patients are mobilized in their own shoe with partial weight bearing of 20 kg for 6-12 weeks depending on fracture severity and bone quality. Over a 4-year period, 163 patients with 184 displaced, intra-articular calcaneal fractures were treated with a lateral plate via an extended approach. In all, 102 patients with 116 fractures were followed for a mean of 8 years. A surgical revision was necessary in 4 cases (3.4%) of postoperative hematoma, 2 (1.7%) superficial and 5 (4.3%) deep infections. Of the latter, 2 patients needed a free flap for definite wound coverage, no calcanectomy or amputation was needed. Secondary subtalar fusion for symptomatic posttraumatic arthritis was

  4. Characteristics of Cervical Spine Injury in Pediatric Patients With Facial Fractures.

    PubMed

    Halsey, Jordan N; Hoppe, Ian C; Marano, Andrew A; Kordahi, Anthony M; Lee, Edward S; Granick, Mark S

    2016-01-01

    Cervical spine injury may present with pediatric patients having sustained fractures of the craniofacial skeleton. Management considerations of the cervical spine often take priority to the fractures of the facial skeleton. The goal of this study was to examine this subset of patients with a focus on initial presentation and need for intervention. A retrospective review from 2000 to 2012 of all facial fractures in patients ≤ 18 years at a level 1 trauma center was performed. Patient demographics, location of fractures, and the presence of a cervical spine injury were collected. During this time period, 285 patients met inclusion criteria. Ten patients were found to have a cervical spine injury. Fractures of the zygoma and orbit were significantly associated with a cervical spine injury. Patients with a cervical spine injury had a Glasgow Coma Scale of 11.2 compared with 13.8 in those without (P < 0.05). C1 was injured in 4 patients, C2 in 2 patients, and C3 to C7 in 4 patients. A surgical airway was required in 1 patient, and 6 were intubated in the trauma bay. Fractures of the mandible were significantly associated with injury to C2. Le Fort fractures and palate fractures approached significance with injury to C1. Only 1 patient had neurologic impairment at presentation, manifested as upper extremity parasthesias, and underwent decompression and fusion in the operating room. Those patients admitted (90%) were all admitted for reasons other than management of the cervical spine injury. The majority of patients (70%) were treated with collar immobilization. One patient expired. No patients had a neurologic deficit at the time of discharge. In this study only 1 cervical spine injury necessitated intervention, with an eventual full recovery. Cervical spine injuries presenting with fractures of the facial skeleton appear to be relatively benign in this series; however, care must be taken to identify all such injuries to avoid exacerbation during maneuvers commonly

  5. Tethers as Debris: Simulating Impacts of Tether Fragments on Shuttle Tiles

    NASA Technical Reports Server (NTRS)

    Evans, Steven W.

    2004-01-01

    The SPHC hydrodynamic code was used to simulate impacts of Kevlar and aluminum projectiles on a model of the LI-900 type insulating tiles used on Space Shuffle Orbiters The intent was to examine likely damage that such tiles might experience if impacted by orbital debris consisting of tether fragments. Projectile speeds ranged from 300 meters per second to 10 kilometers per second. Damage is characterized by penetration depth, tile surface-hole diameter, tile body-cavity diameter, coating fracture diameter, tether and cavity wall material phases, and deformation of the aluminum backwall.

  6. Investigation of the Effect of Cemented Fractures on Fracturing Network Propagation in Model Block with Discrete Orthogonal Fractures

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Li, C. H.

    2017-07-01

    Researchers have recently realized that the natural fractures in shale reservoirs are often cemented or sealed with various minerals. However, the influence of cement characteristics of natural fracture on fracturing network propagation is still not well understood. In this work, laboratory-scaled experiments are proposed to prepare model blocks with discrete orthogonal fractures network with different strength of natural fracture, in order to reveal the influence of cemented natural fractures on the interactions between hydraulic fractures and natural fractures. A series of true triaxial hydraulic fracturing experiments were conducted to investigate the mechanism of hydraulic fracture initiation and propagation in model blocks with natural fractures of different cement strength. The results present different responses of interactions between hydraulic and natural fractures, which can be reflected on the pump pressure profiles and block failure morphology. For model blocks with fluctuated pump pressure curves, the communication degree of hydraulic and natural fractures is good, which is confirmed by a proposed new index of "P-SRV." The most significant finding is that too high and too low strength properties of cemented natural fracture are adverse to generate complex fracturing network. This work can help us better understand how cemented natural fractures affect the fracturing network propagation subsurface and give us reference to develop more accurate hydraulic fracturing models.

  7. Skull fracture

    MedlinePlus

    Basilar skull fracture; Depressed skull fracture; Linear skull fracture ... Skull fractures may occur with head injuries . The skull provides good protection for the brain. However, a severe impact ...

  8. Analysis of orbital perturbations acting on objects in orbits near geosynchronous earth orbit

    NASA Technical Reports Server (NTRS)

    Friesen, Larry J.; Jackson, Albert A., IV; Zook, Herbert A.; Kessler, Donald J.

    1992-01-01

    The paper presents a numerical investigation of orbital evolution for objects started in GEO or in orbits near GEO in order to study potential orbital debris problems in this region. Perturbations simulated include nonspherical terms in the earth's geopotential field, lunar and solar gravity, and solar radiation pressure. Objects simulated include large satellites, for which solar radiation pressure is insignificant, and small particles, for which solar radiation pressure is an important force. Results for large satellites are largely in agreement with previous GEO studies that used classical perturbation techniques. The orbit plane of GEO satellites placed in a stable plane orbit inclined approximately 7.3 deg to the equator experience very little precession, remaining always within 1.2 percent of their initial orientation. Solar radiation pressure generates two major effects on small particles: an orbital eccentricity oscillation anticipated from previous research, and an oscillation in orbital inclination.

  9. Post-depositional fracturing and subsidence of pumice flow deposits: Lascar Volcano, Chile.

    PubMed

    Whelley, Patrick L; Jay, J; Calder, E S; Pritchard, M E; Cassidy, N J; Alcaraz, S; Pavez, A

    Unconsolidated pyroclastic flow deposits of the 1993 eruption of Lascar Volcano, Chile, have, with time, become increasingly dissected by a network of deeply penetrating fractures. The fracture network comprises orthogonal sets of decimeter-wide linear voids that form a pseudo-polygonal grid visible on the deposit surface. In this work, we combine shallow surface geophysical imaging tools with remote sensing observations and direct field measurements of the deposit to investigate these fractures and their underlying causal mechanisms. Based on ground penetrating radar images, the fractures are observed to have propagated to depths of up to 10 m. In addition, orbiting radar interferometry shows that deposit subsidence of up to 1 cm/year -1 occurred between 1993 and 1996 with continued subsidence occurring at a slower rate thereafter. In situ measurements show that 1 m below the surface, the 1993 deposits remain 5°C to 15°C hotter, 18 years after emplacement, than adjacent deposits. Based on the observed subsidence as well as estimated cooling rates, the fractures are inferred to be the combined result of deaeration, thermal contraction, and sedimentary compaction in the months to years following deposition. Significant environmental factors, including regional earthquakes in 1995 and 2007, accelerated settling at punctuated moments in time. The spatially variable fracture pattern relates to surface slope and lithofacies variations as well as substrate lithology. Similar fractures have been reported in other ignimbrites but are generally exposed only in cross section and are often attributed to formation by external forces. Here we suggest that such interpretations should be invoked with caution, and deformation including post-emplacement subsidence and fracturing of loosely packed ash-rich deposits in the months to years post-emplacement is a process inherent in the settling of pyroclastic material.

  10. Density functional theory (DFT) study of a new novel bionanosensor hybrid; tryptophan/Pd doped single walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Yoosefian, Mehdi; Etminan, Nazanin

    2016-07-01

    In order to explore a new novel L-amino acid/transition metal doped single walled carbon nanotube based biosensor, density functional theory calculations were studied. These hybrid structures of organic-inorganic nanobiosensors are able to detect the smallest amino acid building block of proteins. The configurations of amine and carbonyl group coordination of tryptophan aromatic amino acid adsorbed on Pd/doped single walled carbon nanotube were compared. The frontier molecular orbital theory, quantum theory atom in molecule and natural bond orbital analysis were performed. The molecular electrostatic potential and the electron density surfaces were constructed. The calculations indicated that the Pd/SWCNT was sensitive to tryptophan suggesting the importance of interaction with biological molecule and potential detecting application. The proposed nanobiosensor represents a highly sensitive detection of protein at ultra-low concentration in diagnosis applications.

  11. [Delayed endoscopic reconstruction of the anterior wall of the frontal sinus: Technical note].

    PubMed

    Mommers, X-A; Zwetyenga, N; Meningaud, J-P

    2015-11-01

    Reconstruction of the anterior wall of the frontal sinus usually requires a coronal incision. This extended approach may lead to paresthesia, unsightly scars, bruises and cicatricial alopecia. These complications encouraged several authors to endoscopic management of this kind of fractures. We present a delayed technique of reconstruction of the anterior wall of the frontal sinus by means of endoscopic hydroxyapatite filling. Two incisions were performed behind the hair line. Subperiosteal dissection using a periosteal elevator was performed. A 30° angled endoscope was used to visualize the depression. The latter was filled by Hydroset® (Stryker, USA) as a bone substitute. In the absence of contra-indication, the reconstruction of the anterior wall of the frontal sinus by means of endoscopic hydroxyapatite filling has many advantages including uneventful outcome, reduction of the hospital stay and a fast learning curve. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  12. Preparation and characterization of functionalized single walled carbon nanotubes (fSWCNT)/ Hydroxyapatite (HAp)-Nylon hybridized composite biomaterial to study the mechanical properties

    NASA Astrophysics Data System (ADS)

    Khanal, Suraj; Leventouri, Theodora; Mahfuz, Hassan; Rondinone, Adam

    2014-03-01

    Synthetic hydroxyapatite (HAp) bears poor mechanical properties that limit its applicability in orthopedics. We study the possibility of overcoming such limitations by incorporating functionalized single walled carbon nanotubes (fSWCNT) in a biocompatible/bioactive nano-composite. We present results from synthesis and characterization of samples prepared under different processing parameters. Ultra sonication method was to disperse functionalized single walled carbon nanotubes (fSWCNT) in HAp followed by a simple hot assorting method to incorporate with polymerized ɛ-caprolactam. The fracture toughness of the composite materials was tested in compliance with the ASTM D-5045 standard. We have found that while the fracture toughness strongly depends on the processing parameters, a value comparable to the one for cortical bone is achieved. Mechanical properties, electron microscopy and crystal structure properties of the composite materials will be discussed.

  13. Long-period tilt-induced accelerations associated with hydraulic fracturing

    NASA Astrophysics Data System (ADS)

    Milkereit, Claus; Dahm, Torsten; Cesca, Simone; Lopez, Jose; Nooshiri, Nima; Zang, Arno

    2017-04-01

    In 2015, several small scale hydrofracture experiments have been performed in situ from a horizontal borehole in a mine gallery in granitic rock. The hydrofracture experiments were monitored by a bundle of different near field sensors covering a broad range of frequencies (see Zang et al., Geophys. J. Int. (2017) 208, 790-813, doi: 10.1093/gji/ggw430). We installed broad band sensors in the gallery close to the fracture experiments, and observed clear long period transients on the horizontal components, with timing and polarity correlated with the opening and closing of the fractures. We interpret the broadband signals as tilt-induced excursions. The broadband signals have been measured independent whether high frequency acoustic emission have been observed or not during the individual fracture experiments. They are thus an independent measure of the success of a hydrofracture experiment and the parameter of the newly formed cracks. In this study we show that most tilt-induced long-period signals can be modeled by a rectangular crack with constant opening in an elastic full space, as first order approximation. From theoretical forward modeling, we proof that the tilt has a higher sensitivity to resolve the strike of the fracture than the displacement field. With this model, we retrieve the strike of the fractures from the tilt observed at a single sensor. The results indicate that the strike angles of the hydrofractures change systematically with the distance to the gallery wall, indicating a rotation of the principal stresses close to the free surface of the gallery. The rotation trend is similar to the one observed in previous hydrofracture experiments in mines. We compare the strength of the modeled tensile cracks, i.e. opening times crack area, with the volume of the injected fluid, and discuss the general resolving power of tilt signals for source parameter fractures. The temporal evolution of the opening and closure of the fractures is discussed.

  14. Solid Propulsion De-Orbiting and Re-Orbiting

    NASA Astrophysics Data System (ADS)

    Schonenborg, R. A. C.; Schoyer, H. F. R.

    2009-03-01

    With many "innovative" de-orbit systems (e.g. tethers, aero breaking, etc.) and with natural de-orbit, the place of impact of unburned spacecraft debris on Earth can not be determined accurately. The idea that satellites burn up completely upon re-entry is a common misunderstanding. To the best of our knowledge only rocket motors are capable of delivering an impulse that is high enough, to conduct a de-orbit procedure swiftly, hence to de-orbit at a specific moment that allows to predict the impact point of unburned spacecraft debris accurately in remote areas. In addition, swift de-orbiting will reduce the on-orbit time of the 'dead' satellite, which reduces the chance of the dead satellite being hit by other dead or active satellites, while spiralling down to Earth during a slow, 25 year, or more, natural de-orbit process. Furthermore the reduced on-orbit time reduces the chance that spacecraft batteries, propellant tanks or other components blow up and also reduces the time that the object requires tracking from Earth.The use of solid propellant for the de-orbiting of spacecraft is feasible. The main advantages of a solid propellant based system are the relatively high thrust and the facts that the system can be made autonomous quite easily and that the system can be very reliable. The latter is especially desirable when one wants to de-orbit old or 'dead' satellites that might not be able to rely anymore on their primary systems. The disadvantage however, is the addition of an extra system to the spacecraft as well as a (small) mass penalty. [1]This paper describes the above mentioned system and shows as well, why such a system can also be used to re-orbit spacecraft in GEO, at the end of their life to a graveyard orbit.Additionally the system is theoretically compared to an existing system, of which performance data is available.A swift market analysis is performed as well.

  15. Lunar floor-fractured craters as magmatic intrusions: Geometry, modes of emplacement, associated tectonic and volcanic features, and implications for gravity anomalies

    NASA Astrophysics Data System (ADS)

    Jozwiak, Lauren M.; Head, James W.; Wilson, Lionel

    2015-03-01

    Lunar floor-fractured craters are a class of 170 lunar craters with anomalously shallow, fractured floors. Two end-member processes have been proposed for the floor formation: viscous relaxation, and subcrater magmatic intrusion and sill formation. Recent morphometric analysis with new Lunar Reconnaissance Orbiter Laser Altimeter (LOLA) and image (LROC) data supports an origin related to shallow magmatic intrusion and uplift. We find that the distribution and characteristics of the FFC population correlates strongly with crustal thickness and the predicted frequency distribution of overpressurization values of magmatic dikes. For a typical nearside lunar crustal thickness, dikes with high overpressurization values favor surface effusive eruptions, medium values favor intrusion and sill formation, and low values favor formation of solidified dikes concentrated lower in the crust. We develop a model for this process, make predictions for the morphologic, morphometric, volcanic, and geophysical consequences of the process and then compare these predictions with the population of observed floor-fractured craters. In our model, the process of magmatic intrusion and sill formation begins when a dike propagates vertically towards the surface; as the dike encounters the underdense brecciated region beneath the crater, the magmatic driving pressure is insufficient to continue vertical propagation, but pressure in the stalled dike exceeds the local lithostatic pressure. The dike then begins to propagate laterally forming a sill which does not propagate past the crater floor region because increased overburden pressure from the crater wall and rim crest pinch off the dike at this boundary; the sill then continues to inflate, further raising and fracturing the brittle crater floor. When the intrusion diameter to intrusion depth ratio is smaller than a critical value, the intrusion assumes a laccolith shape with a domed central region. When the ratio exceeds a critical value

  16. Failure Analysis of Fractured Poppet from Space Shuttle Orbiter Flow Control Valve

    NASA Technical Reports Server (NTRS)

    Russell, Richard

    2010-01-01

    This slide presentation reviews the failure analysis of a fractured poppet from a flow control valve (FCV) used on the space shuttle. This presentation has focused on the laboratory analysis of the failed hardware. The use of Scanning electron fractography during the investigation led to the conclusion that the poppet failed due to fatigue cracking that, most likely, occurred under changing loading conditions. The initial investigation led to a more thorough test of poppets that had been retired, this testing led to the conclusion that the thumbnail cracks in the flight hardware had existed for the life of the shuttle program. This led to a program to develop an eddy current technique that was capable of detecting small very tight cracks.

  17. A Review of Large-Scale Fracture Experiments Relevant to Pressure Vessel Integrity Under Pressurized Thermal Shock Conditions

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

    Pugh, C.E.

    2001-01-29

    Numerous large-scale fracture experiments have been performed over the past thirty years to advance fracture mechanics methodologies applicable to thick-wall pressure vessels. This report first identifies major factors important to nuclear reactor pressure vessel (RPV) integrity under pressurized thermal shock (PTS) conditions. It then covers 20 key experiments that have contributed to identifying fracture behavior of RPVs and to validating applicable assessment methodologies. The experiments are categorized according to four types of specimens: (1) cylindrical specimens, (2) pressurized vessels, (3) large plate specimens, and (4) thick beam specimens. These experiments were performed in laboratories in six different countries. This reportmore » serves as a summary of those experiments, and provides a guide to references for detailed information.« less

  18. Evolution of fracture permeability of ultramafic rocks undergoing serpentinization at hydrothermal conditions: An experimental study

    NASA Astrophysics Data System (ADS)

    Farough, A.; Moore, D. E.; Lockner, D. A.; Lowell, R. P.

    2016-01-01

    We performed flow-through laboratory experiments on five cylindrically cored samples of ultramafic rocks, in which we generated a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at a confining pressure of 50 MPa, pore pressure of 20 MPa, and temperature of 260°C, simulating a depth of 2 km under hydrostatic conditions. A pore pressure difference of up to 2 MPa was imposed across the ends of the sample. Fracture permeability decreased by 1-2 orders of magnitude during the 200-330 h experiments. Electron microprobe and SEM data indicated the formation of needle-shaped crystals of serpentine composition along the walls of the fracture, and chemical analyses of sampled pore fluids were consistent with dissolution of ferro-magnesian minerals. By comparing the difference between fracture permeability and matrix permeability measured on intact samples of the same rock types, we concluded that the contribution of the low matrix permeability to flow is negligible and essentially all of the flow is focused in the tensile fracture. The experimental results suggest that the fracture network in long-lived hydrothermal circulation systems can be sealed rapidly as a result of mineral precipitation, and generation of new permeability resulting from a combination of tectonic and crystallization-induced stresses is required to maintain fluid circulation.

  19. Evolution of fracture permeability of ultramafic rocks undergoing serpentinization at hydrothermal conditions: An experimental study

    USGS Publications Warehouse

    Farough, Aida; Moore, Diane E.; Lockner, David A.; Lowell, R.P.

    2016-01-01

    We performed flow-through laboratory experiments on five cylindrically cored samples of ultramafic rocks, in which we generated a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at a confining pressure of 50 MPa, pore pressure of 20 MPa, and temperature of 260°C, simulating a depth of 2 km under hydrostatic conditions. A pore pressure difference of up to 2 MPa was imposed across the ends of the sample. Fracture permeability decreased by 1–2 orders of magnitude during the 200–330 h experiments. Electron microprobe and SEM data indicated the formation of needle-shaped crystals of serpentine composition along the walls of the fracture, and chemical analyses of sampled pore fluids were consistent with dissolution of ferro-magnesian minerals. By comparing the difference between fracture permeability and matrix permeability measured on intact samples of the same rock types, we concluded that the contribution of the low matrix permeability to flow is negligible and essentially all of the flow is focused in the tensile fracture. The experimental results suggest that the fracture network in long-lived hydrothermal circulation systems can be sealed rapidly as a result of mineral precipitation, and generation of new permeability resulting from a combination of tectonic and crystallization-induced stresses is required to maintain fluid circulation.

  20. Ballistic fractures: indirect fracture to bone.

    PubMed

    Dougherty, Paul J; Sherman, Don; Dau, Nathan; Bir, Cynthia

    2011-11-01

    Two mechanisms of injury, the temporary cavity and the sonic wave, have been proposed to produce indirect fractures as a projectile passes nearby in tissue. The purpose of this study is to evaluate the temporal relationship of pressure waves using strain gauge technology and high-speed video to elucidate whether the sonic wave, the temporary cavity, or both are responsible for the formation of indirect fractures. Twenty-eight fresh frozen cadaveric diaphyseal tibia (2) and femurs (26) were implanted into ordnance gelatin blocks. Shots were fired using 9- and 5.56-mm bullets traversing through the gelatin only, passing close to the edge of the bone, but not touching, to produce an indirect fracture. High-speed video of the impact event was collected at 20,000 frames/s. Acquisition of the strain data were synchronized with the video at 20,000 Hz. The exact time of fracture was determined by analyzing and comparing the strain gauge output and video. Twenty-eight shots were fired, 2 with 9-mm bullets and 26 with 5.56-mm bullets. Eight indirect fractures that occurred were of a simple (oblique or wedge) pattern. Comparison of the average distance of the projectile from the bone was 9.68 mm (range, 3-20 mm) for fractured specimens and 15.15 mm (range, 7-28 mm) for nonfractured specimens (Student's t test, p = 0.036). In this study, indirect fractures were produced after passage of the projectile. Thus, the temporary cavity, not the sonic wave, was responsible for the indirect fractures.

  1. Hydraulic fracture propagation modeling and data-based fracture identification

    NASA Astrophysics Data System (ADS)

    Zhou, Jing

    Successful shale gas and tight oil production is enabled by the engineering innovation of horizontal drilling and hydraulic fracturing. Hydraulically induced fractures will most likely deviate from the bi-wing planar pattern and generate complex fracture networks due to mechanical interactions and reservoir heterogeneity, both of which render the conventional fracture simulators insufficient to characterize the fractured reservoir. Moreover, in reservoirs with ultra-low permeability, the natural fractures are widely distributed, which will result in hydraulic fractures branching and merging at the interface and consequently lead to the creation of more complex fracture networks. Thus, developing a reliable hydraulic fracturing simulator, including both mechanical interaction and fluid flow, is critical in maximizing hydrocarbon recovery and optimizing fracture/well design and completion strategy in multistage horizontal wells. A novel fully coupled reservoir flow and geomechanics model based on the dual-lattice system is developed to simulate multiple nonplanar fractures' propagation in both homogeneous and heterogeneous reservoirs with or without pre-existing natural fractures. Initiation, growth, and coalescence of the microcracks will lead to the generation of macroscopic fractures, which is explicitly mimicked by failure and removal of bonds between particles from the discrete element network. This physics-based modeling approach leads to realistic fracture patterns without using the empirical rock failure and fracture propagation criteria required in conventional continuum methods. Based on this model, a sensitivity study is performed to investigate the effects of perforation spacing, in-situ stress anisotropy, rock properties (Young's modulus, Poisson's ratio, and compressive strength), fluid properties, and natural fracture properties on hydraulic fracture propagation. In addition, since reservoirs are buried thousands of feet below the surface, the

  2. Clavicle fractures: epidemiology, classification and treatment of 2 422 fractures in the Swedish Fracture Register; an observational study.

    PubMed

    Kihlström, Caroline; Möller, Michael; Lönn, Katarina; Wolf, Olof

    2017-02-15

    Large multi-centre studies of clavicle fractures have so far been missing. The aim of this observational study was to describe the epidemiology, classification and treatment of clavicle fractures in the The Swedish Fracture Register (SFR) that collects national prospective data from large fracture populations. Data were retrieved from the SFR on all clavicle fractures sustained by patients ≥ 15 years of age in 2013-2014 (n = 2 422) with regards to date of injury, cause of injury, fracture classification and treatment. Sixty-eight per cent of the clavicle fractures occurred in males. The largest subgroup was males aged 15-24 years, representing 21% of clavicle fractures. At the ages of 65 years and above, females sustained more clavicle fractures than males. Same-level falls and bicycle accidents were the most common injury mechanisms. Displaced midshaft fractures constituted 43% of all fractures and were the most frequently operated fractures. Seventeen per cent of the patients underwent operative treatment within 30 days of the injury, where plate fixation was the choice of treatment in 94% of fractures. The largest patient group was young males. Displaced midshaft fractures were the most common type of clavicle fracture as well as the most frequently operated type of fracture.

  3. Dentin-like versus Rigid Endodontic Post: 11-year Randomized Controlled Pilot Trial on No-wall to 2-wall Defects.

    PubMed

    Naumann, Michael; Sterzenbach, Guido; Dietrich, Thomas; Bitter, Kerstin; Frankenberger, Roland; von Stein-Lausnitz, Manja

    2017-11-01

    This is the first long-term randomized controlled trial to evaluate dentin-like glass fiber posts (GFPs) compared with rather rigid titanium posts (TPs) for post-endodontic restoration of severely damaged endodontically treated teeth with 2 or fewer remaining cavity walls. Ninety-one subjects in need of post-endodontic restorations were randomly assigned to receive either a tapered GFP (n = 45) or TP (n = 46). Posts were adhesively luted by using self-adhesive resin cement, followed by composite core build-up and preparation of 2-mm ferrule design. Primary end point was loss of restoration for any reason. Kaplan-Meier curves were constructed, and log-rank test was calculated (P < .05). After a follow-up of 132 months, 17 GFP and 20 TP restorations survived, and 19 failed (12 GFP, 7 TP). Failure modes for GFP were root fracture (n = 4), core fracture (n = 1), secondary caries (n = 1), endodontic failure (n = 2), extraction because of tooth mobility grade III associated with insufficient design of removable partial denture (n = 1), tooth fracture (n = 1), and changes in treatment plan (n = 2); failure modes for TP were endodontic failure (n = 5), root fracture (n = 1), and 1 extraction for other reasons. Cumulative survival probability was 58.7% for GFP and 74.2% for TP. When using self-adhesively luted prefabricated posts, resin composite core build-up, and 2-mm ferrule to reconstruct severely damaged endodontically treated teeth, tooth survival is not influenced by post rigidity. Survival decreased rapidly after 8 years of observation in both groups. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Risk factors that predict mortality in patients with blunt chest wall trauma: a systematic review and meta-analysis.

    PubMed

    Battle, Ceri E; Hutchings, Hayley; Evans, Phillip A

    2012-01-01

    The risk factors for mortality following blunt chest wall trauma have neither been well established or summarised. To summarise the risk factors for mortality in blunt chest wall trauma patients based on available evidence in the literature. A systematic review of English and non-English articles using MEDLINE, EMBASE and the Cochrane Library from their introduction until May 2010. Additional studies were identified by hand-searching bibliographies and contacting relevant clinical experts. Grey literature was sought by searching abstracts from all Emergency Medicine conferences. Broad search terms and inclusion criteria were used to reduce the number of missed studies. A two step study selection process was used. All published and unpublished observational studies were included if they investigated estimates of association between a risk factor and mortality for blunt chest wall trauma patients. A two step data extraction process using pre-defined data fields, including study quality indicators. Each study was appraised using a previously designed quality assessment tool and the STROBE checklist. Where sufficient data were available, odds ratios with 95% confidence intervals were calculated using Mantel-Haenszel method for the risk factors investigated. The I(2) statistic was calculated for combined studies in order to assess heterogeneity. Age, number of rib fractures, presence of pre-existing disease and pneumonia were found to be related to mortality in 29 identified studies. Combined odds ratio of 1.98 (1.86-2.11, 95% CI), 2.02 (1.89-2.15, 95% CI), 2.43 (1.03-5.72, 95% CI) and 5.24 (3.51-7.82) for mortality were calculated for blunt chest wall trauma patients aged 65 years or more, with three or more rib fractures, pre-existing conditions and pneumonia respectively. The risk factors for mortality in patients sustaining blunt chest wall trauma were a patient age of 65 years or more, three or more rib fractures and the presence of pre-existing disease especially

  5. Numerical and Experimental Studies of Particle Settling in Real Fracture Geometries

    NASA Astrophysics Data System (ADS)

    Roy, Pratanu; Du Frane, Wyatt L.; Kanarska, Yuliya; Walsh, Stuart D. C.

    2016-11-01

    , capable of explicitly representing the particles, the fracture surface and the interstitial fluid flow. Both studies reveal large-scale vortex motion during particle settling. For the most part, this behavior is independent of the fracture topology, instead driven by interactions between the sinking particles and the upwelling interstitial fluid. This motion results in large amounts of particle dispersion, significantly greater than might be expected from traditional slurry models. The competition between the particles and the fluid also results in a redistribution of particles toward the fracture walls, which has significant implications for the transport of proppant along the fracture.

  6. Shuttle on-orbit rendezvous targeting: Circular orbits

    NASA Technical Reports Server (NTRS)

    Bentley, E. L.

    1972-01-01

    The strategy and logic used in a space shuttle on-orbit rendezvous targeting program are described. The program generates ascent targeting conditions for boost to insertion into an intermediate parking orbit, and generates on-orbit targeting and timeline bases for each maneuver to effect rendezvous with a space station. Time of launch is determined so as to eliminate any plane change, and all work was performed for a near-circular space station orbit.

  7. Castiglione (Oletta, Corsica): relationships between phenomena of calcification and tectonic fossiliferous fracture dating

    NASA Astrophysics Data System (ADS)

    Pereira, Elisabeth; Rouzaud, François; Salotti, Michelle; Dubois, Jean-Noël; Ferrandini, Jean; Ottaviani-Spella, Marie-Madeleine; Quinif, Yves

    Six cavities have been discovered in the Oletta massif. The massif, today constitued of Schistes lustrés with several metres of calcareous layers above them, has undergone intense fracturing. The networks of cavities are organised along north-south and subequatorial directions, and form a narrow bayonnet-network. All the elements in the galleries appear to be karstic: stalagmites, stalactites and calcitic deposits along the walls; but no trace of dissolution or excavation was found. Thus, the origin of the galleries is only tectonic, while the calcitic deposits result from the dissolution of the old, thick calcareous layers above, which are no longer present. The thickness and the volume of the calcitic deposits, which is variable depending on the galleries, indicates the chronology of the different tectonic periods which have fractured the massif. Five tectonic and successsive events have been detected. Calcitic datings confirm the timing of successional fracturing, indicating also the variable age of the fossiliferous Middle Pleistocene deposits found in these cavities.

  8. Ankle fracture spur sign is pathognomonic for a variant ankle fracture.

    PubMed

    Hinds, Richard M; Garner, Matthew R; Lazaro, Lionel E; Warner, Stephen J; Loftus, Michael L; Birnbaum, Jacqueline F; Burket, Jayme C; Lorich, Dean G

    2015-02-01

    The hyperplantarflexion variant ankle fracture is composed of a posterior tibial lip fracture with posterolateral and posteromedial fracture fragments separated by a vertical fracture line. This infrequently reported injury pattern often includes an associated "spur sign" or double cortical density at the inferomedial tibial metaphysis. The objective of this study was to quantitatively establish the association of the ankle fracture spur sign with the hyperplantarflexion variant ankle fracture. Our clinical database of operative ankle fractures was retrospectively reviewed for the incidence of hyperplantarflexion variant and nonvariant ankle fractures as determined by assessment of injury radiographs, preoperative advanced imaging, and intraoperative observation. Injury radiographs were then evaluated for the presence of the spur sign, and association between the spur sign and variant fractures was analyzed. The incidence of the hyperplantarflexion variant fracture among all ankle fractures was 6.7% (43/640). The spur sign was present in 79% (34/43) of variant fractures and absent in all nonvariant fractures, conferring a specificity of 100% in identifying variant fractures. Positive predictive value and negative predictive value were 100% and 99%, respectively. The ankle fracture spur sign was pathognomonic for the hyperplantarflexion variant ankle fracture. It is important to identify variant fractures preoperatively as patient positioning, operative approach, and fixation construct of variant fractures often differ from those employed for osteosynthesis of nonvariant fractures. Identification of the spur sign should prompt acquisition of advanced imaging to formulate an appropriate operative plan to address the variant fracture pattern. Level III, retrospective comparative study. © The Author(s) 2014.

  9. Three dimensional fracture aperture and porosity distribution using computerized tomography

    NASA Astrophysics Data System (ADS)

    Wenning, Q.; Madonna, C.; Joss, L.; Pini, R.

    2017-12-01

    A wide range of geologic processes and geo-engineered applications are governed by coupled hydromechanical properties in the subsurface. In geothermal energy reservoirs, quantifying the rate of heat transfer is directly linked with the transport properties of fractures, underscoring the importance of fracture aperture characterization for achieving optimal heat production. In this context, coupled core-flooding experiments with non-invasive imaging techniques (e.g., X-Ray Computed Tomography - X-Ray CT) provide a powerful method to make observations of these properties under representative geologic conditions. This study focuses on quantifying fracture aperture distribution in a fractured westerly granite core by using a recently developed calibration-free method [Huo et al., 2016]. Porosity is also estimated with the X-ray saturation technique using helium and krypton gases as saturating fluids, chosen for their high transmissibility and high CT contrast [e.g., Vega et al., 2014]. The westerly granite sample (diameter: 5 cm, length: 10 cm) with a single through-going rough-walled fracture was mounted in a high-pressure aluminum core-holder and placed inside a medical CT scanner for imaging. During scanning the pore fluid pressure was undrained and constant, and the confining pressure was regulated to have the desired effective pressure (0.5, 5, 7 and 10 MPa) under loading and unloading conditions. 3D reconstructions of the sample have been prepared in terms of fracture aperture and porosity at a maximum resolution of (0.24×0.24×1) mm3. Fracture aperture maps obtained independently using helium and krypton for the whole core depict a similar heterogeneous aperture field, which is also dependent on confining pressure. Estimates of the average hydraulic aperture from CT scans are in quantitative agreement with results from fluid flow experiments. However, the latter lack of the level of observational detail achieved through imaging, which further evidence the

  10. Clavicle fractures.

    PubMed

    Ropars, M; Thomazeau, H; Huten, D

    2017-02-01

    Management of clavicle fracture has progressed over the last decade, notably with wider use of surgery in midshaft fracture, and new techniques for lateral fracture. Midshaft clavicle fracture treatment needs to be personalized and adapted to the patient's activity level. Whichever the segment involved, treatment for non-displaced fracture is functional; elbow-to-body sling immobilization seems the best tolerated. Apart from regular surgical indications (shoulder impaction, floating shoulder, open fracture or fracture with neurovascular complications), surgery is recommended in case of bone shortening exceeding 1.5cm in young active patients. The technique needs to take account of clavicle anatomy: notably periosteal vascularization in midshaft fracture and acromioclavicular ligament integrity and location in case of lateral fracture. Plate osteosynthesis should take account of bone diameter and 3D curvature; intramedullary fixation should take account of intramedullary canal morphology. Although iatrogenic vascular complications are rare, vessel relations and variants need to be known, especially in the medial end of the clavicle and midshaft. Lateral segment fractures are a particular entity. Large-scale randomized studies are needed to assess indications and results for the various possible internal fixation techniques: isolated or associated to ligament reconstruction, rigid or flexible, and open or arthroscopic. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  11. Association of Ipsilateral Rib Fractures With Displacement of Midshaft Clavicle Fractures.

    PubMed

    Stahl, Daniel; Ellington, Matthew; Brennan, Kindyle; Brennan, Michael

    2017-04-01

    To determine whether the presence of ipsilateral rib fractures affects the rate of a clavicle fracture being unstable (>100% displacement). A retrospective review from 2002-2013 performed at a single level 1 trauma center evaluated 243 midshaft clavicle fractures. Single Level 1 trauma center. These fractures were subdivided into those with ipsilateral rib fractures (CIR; n = 149) and those without ipsilateral rib fractures (CnIR; n = 94). The amount of displacement was measured on the initial injury radiograph and subsequent follow-up radiographs. Fractures were classified into either <100% displacement or >100% displacement, based on anteroposterior radiographs. Ipsilateral rib fractures were recorded based on which number rib was fractured and the total number of fractured ribs. One hundred sixteen (78%) of the CIR group and 51 (54%) of the CnIR group were found to have >100% displacement at follow-up (P = 0.0047). Seventy-two percent of the CIR group demonstrated progression from <100% to >100% displacement of the fracture compared with only 54% of the CnIR group (P < 0.05). The odds ratio for progression of the clavicle fracture to >100% was 4.08 (P = 0.000194) when ribs 1-4 were fractured and not significant for rib fractures 5-8 or 9-12. The presence of concomitant ipsilateral rib fractures significantly increases the rate of midshaft clavicle fractures being >100% displaced. In addition, a fracture involving the upper one-third of the ribs significantly increases the rate of the clavicle fracture being >100% displaced on early follow-up. Clavicle fractures with associated ipsilateral rib fractures tend to demonstrate an increased amount of displacement on follow-up radiographs compared with those without ipsilateral rib fractures. Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

  12. Spatially and time-resolved magnetization dynamics driven by spin-orbit torques

    NASA Astrophysics Data System (ADS)

    Baumgartner, Manuel; Garello, Kevin; Mendil, Johannes; Avci, Can Onur; Grimaldi, Eva; Murer, Christoph; Feng, Junxiao; Gabureac, Mihai; Stamm, Christian; Acremann, Yves; Finizio, Simone; Wintz, Sebastian; Raabe, Jörg; Gambardella, Pietro

    2017-10-01

    Current-induced spin-orbit torques are one of the most effective ways to manipulate the magnetization in spintronic devices, and hold promise for fast switching applications in non-volatile memory and logic units. Here, we report the direct observation of spin-orbit-torque-driven magnetization dynamics in Pt/Co/AlOx dots during current pulse injection. Time-resolved X-ray images with 25 nm spatial and 100 ps temporal resolution reveal that switching is achieved within the duration of a subnanosecond current pulse by the fast nucleation of an inverted domain at the edge of the dot and propagation of a tilted domain wall across the dot. The nucleation point is deterministic and alternates between the four dot quadrants depending on the sign of the magnetization, current and external field. Our measurements reveal how the magnetic symmetry is broken by the concerted action of the damping-like and field-like spin-orbit torques and the Dzyaloshinskii-Moriya interaction, and show that reproducible switching events can be obtained for over 1012 reversal cycles.

  13. Mars Climate History: Insights From Impact Crater Wall Slope Statistics

    NASA Astrophysics Data System (ADS)

    Kreslavsky, Mikhail A.; Head, James W.

    2018-02-01

    We use the global distribution of the steepest slopes on crater walls derived from Mars Orbiter Laser Altimeter profile data to assess the magnitudes of degradational processes with latitude, altitude, and time. We independently confirm that Amazonian polar/high-latitude crater slope modification is substantial, but that craters in the low latitudes have essentially escaped significant slope modification since the Early Hesperian. We find that the total amount of crater wall degradation in the Late Noachian is very small in comparison to the circumpolar regions in the Late Amazonian, an observation that we interpret to mean that the Late Noachian climate was not characterized by persistent and continuous warm and wet conditions. A confirmed elevational zonality in degradation in the Early Hesperian is interpreted to mean that the atmosphere was denser than today.

  14. Tidal reorientation and the fracturing of Jupiter's moon Europa

    USGS Publications Warehouse

    McEwen, A.S.

    1986-01-01

    The most striking characteristic of Europa is the network of long linear albedo markings over the surface, suggestive of global-scale tectonic processes. Various explanations for the fractures have been proposed: Freezing and expansion of an early liquid water ocean1, planetary expansion due to dehydration of hydrated silicates2, localization by weak points in the crust generated by impacts3, and a combination of stresses due to planetary volume change and tidal distortions from orbital recession and orbital eccentricity4,5. Calculations by Yoder6 and Greenberg and Weidenschilling7 have shown that Europa may rotate slightly more rapidly than the synchronous rate, with a rotation period (reorientation through 360??) ranging from 20 to >103 yr if a liquid mantle is present, or up to 1010 yr if the satellite is essentially solid7. Helfen-stein and Parmentier8 modelled the stresses due to nonsynchronous rotation, and concluded that this could explain the long fractures in part of the anti-jovian hemisphere. In this note, I present a global map of lineaments with long arc lengths (>20?? or 550 km), and compare the lineament orientations to the tensile stress trajectories due to tidal distortions (changes in the lengths of three principal semiaxes) and to nonsynchronous rotation (longitudinal reorientation of two of the principal semiaxes). An excellent orthogonal fit to the lineaments is achieved by the stresses due to nonsynchronous rotation with the axis radial to Jupiter located 25?? east of its present position. This fit suggests that nonsynchronous rotation occurred at some time in Europa's history. ?? 1986 Nature Publishing Group.

  15. The outcome of surgically treated traumatic unstable pelvic fractures by open reduction and internal fixation.

    PubMed

    Mardanpour, Keykhosro; Rahbar, Mahtab

    2013-07-01

    This study was performed to evaluate functional and radiological results of pelvic ring fractures treatment by open reduction and internal fixation. Thirty eight patients with unstable pelvic fractures, treated from 2002 to 2008 were retrospectively reviewed. The mean patients' age was 37 years (range 20 to 67). Twenty six patients were men (4 patients with type B and 22 patients with type C fracture) and 12 women (7 patients with type B and 5 patients with type C fracture). The commonest cause was a road traffic accident (N=37, about 97%). Internal fixation was done by plaque with ilioinguinal and Kocher-Langenbeek approaches for anterior, posterior pelvic wall and acetabulum fracture respectively. Quality of reduction was graded according to Majeed score system. There were 11 type-C and 27 type-B pelvic fractures according to Tile's classification. Thirty six patients sustained additional injuries. The commonest additional injury was lower extremity fracture. The mean follow-up was 45.6 months (range 16 to 84 months).The functional outcome was excellent in 66%, good in 15%, fair in 11% and poor in 7% of the patients with type B pelvic fractures and functional outcome was excellent in 46%, good in 27%, fair in 27% and poor in 0% of the patients with type C pelvic fractures. There were four postoperative infections. No sexual functional problem was reported. Neurologic problem like Lateral cutaneous nerve of thigh injury recovered completely in 2 patients and partially in 2 patients. There was no significant relation between functional outcome and the site of fracture (P greater than 0.005). Unstable pelvic ring fracture injuries should be managed surgically by rigid stabilization. It must be carried out as soon as the general condition of the patient permits, and even up to two weeks.

  16. Regeneration cycle and the covariant Lyapunov vectors in a minimal wall turbulence.

    PubMed

    Inubushi, Masanobu; Takehiro, Shin-ichi; Yamada, Michio

    2015-08-01

    Considering a wall turbulence as a chaotic dynamical system, we study regeneration cycles in a minimal wall turbulence from the viewpoint of orbital instability by employing the covariant Lyapunov analysis developed by [F. Ginelli et al. Phys. Rev. Lett. 99, 130601 (2007)]. We divide the regeneration cycle into two phases and characterize them with the local Lyapunov exponents and the covariant Lyapunov vectors of the Navier-Stokes turbulence. In particular, we show numerically that phase (i) is dominated by instabilities related to the sinuous mode and the streamwise vorticity, and there is no instability in phase (ii). Furthermore, we discuss a mechanism of the regeneration cycle, making use of an energy budget analysis.

  17. The Fate of Colloidal Swarms in Fractures

    NASA Astrophysics Data System (ADS)

    Pyrak-Nolte, L. J.; Olander, M. K.

    2009-12-01

    In the next 10-20 years, nano- and micro-sensor engineering will advance to the stage where sensor swarms could be deployed in the subsurface to probe rock formations and the fluids contained in them. Sensor swarms are groups of nano- or micro- sensors that are maintained as a coherent group to enable either sensor-to-sensor communication and/or coherent transmission of information as a group. The ability to maintain a swarm of sensors depends on the complexity of the flow paths in the rock, on the size and shape of the sensors and on the chemical interaction among the sensors, fluids, and rock surfaces. In this study, we investigate the effect of fracture aperture and fluid currents on the formation, evolution and break-up of colloidal swarms under gravity. Transparent cubic samples (100 mm x 100 mm x 100 mm) containing synthetic fractures with uniform and non-uniform aperture distributions were used to quantify the effect of aperture on swarm formation, swarm velocity, and swarm geometry using optical imaging. A fracture with a uniform aperture distribution was fabricated from two polished rectangular prisms of acrylic. A fracture with a non-uniform aperture distribution was created with a polished rectangular acrylic prism and an acrylic replica of an induced fracture surface from a carbonate rock. A series of experiments were performed to determine how swarm movement and geometry are affected as the walls of the fracture are brought closer together from 50 mm to 1 mm. During the experiments, the fracture was fully saturated with water. We created the swarms using two different particle sizes in dilute suspension (~ 1.0% by mass) . The particles were 3 micron diameter fluorescent polymer beads and 25 micron diameter soda-lime glass beads. The swarm behavior was imaged using an optical fluorescent imaging system composed of a CCD camera illuminated by a 100 mW diode-pumped doubled YAG laser. A swam was created when approximately 0.01 g drop of the suspension was

  18. The clinical application of absorbable intramedullary nail and claw plate on treating multiple rib fractures.

    PubMed

    Chai, X; Lin, Q; Ruan, Z; Zheng, J; Zhou, J; Zhang, J

    2013-08-01

    The absorption intramedullary nail and claw plate indications and efficacy were investigated in the treatment of a life-threatening multiple rib fractures. A retrospective analysis of 248 surgically treated rib fracture patients was performed who admitted to our hospital from March 2007 to December 2012. Intramedullary nailing was performed in 28 cases, a claw-type bone plate was fixed in 141 cases, and a combination of both was fixed in 79 cases. All internal fixation patients were clinically cured except 1 patient died 14 days after a massive pulmonary embolism. The patients with flail chest and floating chest wall causing respiratory and circulatory disorders were promptly corrected. Routine follow-up was from 1 to 2 years, displaced fractures were in 2 cases, and there were 11 cases of internal fixation and extraction. Internal fixation is a simple and reliable method for the treatment of multiple rib fractures. Both internal fixation materials have their pros and cons but the claw bone plate is more robust. The actual selection of appropriate treatment options helps to improve the treatment efficacy.

  19. [Orbital inflammation].

    PubMed

    Mouriaux, F; Coffin-Pichonnet, S; Robert, P-Y; Abad, S; Martin-Silva, N

    2014-12-01

    Orbital inflammation is a generic term encompassing inflammatory pathologies affecting all structures within the orbit : anterior (involvement up to the posterior aspect of the globe), diffuse (involvement of intra- and/or extraconal fat), apical (involvement of the posterior orbit), myositis (involvement of only the extraocular muscles), dacryoadenitis (involvement of the lacrimal gland). We distinguish between specific inflammation and non-specific inflammation, commonly referred to as idiopathic inflammation. Specific orbital inflammation corresponds to a secondary localization of a "generalized" disease (systemic or auto-immune). Idiopathic orbital inflammation corresponds to uniquely orbital inflammation without generalized disease, and thus an unknown etiology. At the top of the differential diagnosis for specific or idiopathic orbital inflammation are malignant tumors, represented most commonly in the adult by lympho-proliferative syndromes and metastases. Treatment of specific orbital inflammation begins with treatment of the underlying disease. For idiopathic orbital inflammation, treatment (most often corticosteroids) is indicated above all in cases of visual loss due to optic neuropathy, in the presence of pain or oculomotor palsy. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  20. Pneumocephalus Following Thoracic Surgery with Posterior Chest Wall Resection.

    PubMed

    Müller, Ina; Tönnies, Mario; Pfannschmidt, Joachim; Kaiser, Dirk

    2015-12-01

    Pneumocephalus can be seen after head injury with fracture of the skull-base or in cerebral neoplasm, infection, or after intracranial or spinal surgery. We report on a 69-year-old male patient with pneumocephalus after right-sided lobectomy and en bloc resection of the chest wall for non-small-cell lung cancer. Postoperatively, the patient showed a reduced vigilance level with no response to pain stimuli and anisocoria. The CCT scan revealed an extensive pneumocephalus; following which, the patient underwent neurosurgery with laminectomy and ligature of the transected nerve roots. After operation the patient returned to his baseline mental status.

  1. PyORBIT: A Python Shell For ORBIT

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

    Jean-Francois Ostiguy; Jeffrey Holmes

    2003-07-01

    ORBIT is code developed at SNS to simulate beam dynamics in accumulation rings and synchrotrons. The code is structured as a collection of external C++ modules for SuperCode, a high level interpreter shell developed at LLNL in the early 1990s. SuperCode is no longer actively supported and there has for some time been interest in replacing it by a modern scripting language, while preserving the feel of the original ORBIT program. In this paper, we describe a new version of ORBIT where the role of SuperCode is assumed by Python, a free, well-documented and widely supported object-oriented scripting language. Wemore » also compare PyORBIT to ORBIT from the standpoint of features, performance and future expandability.« less

  2. A review of micrometeoroid flux measurements and models for low orbital altitudes of the Space Station

    NASA Technical Reports Server (NTRS)

    Susko, M.

    1984-01-01

    A review of meteoroid flux measurements and models for low orbital altitudes of the Space Station has been made in order to provide information that may be useful in design studies and laboratory hypervelocity impact tests which simulate micrometeoroids in space for design of the main wall of the Space Station. This report deals with the meteoroid flux mass model, the defocusing and shielding factors that affect the model, the probability of meteoroid penetration of the main wall of a Space Station. Whipple (1947) suggested a meteoroid bumper, a thin shield around the spacecraft at some distance from the wall, as an effective device for reducing penetration, which has been discussed in this report. The equations of the probability of meteoroid penetration, the average annual cumulative total flux, and the equations for the thickness of the main wall and the bumper are presented in this report.

  3. Development of an efficient Procedure for Resist Wall Space Experiment

    NASA Astrophysics Data System (ADS)

    Matsumoto, Shouhei; Kumasaki, Saori; Higuchi, Sayoko; Kirihata, Kuniaki; Inoue, Yasue; Fujie, Miho; Soga, Kouichi; Wakabayashi, Kazuyuki; Hoson, Takayuki

    The Resist Wall space experiment aims to examine the role of the cortical microtubule-plasma membrane-cell wall continuum in plant resistance to the gravitational force, thereby clarifying the mechanism of gravity resistance. For this purpose, we will cultivate Arabidopsis mutants defective in organization of cortical microtubules (tua6 ) or synthesis of membrane sterols (hmg1 ) as well as the wild type under microgravity and 1 g conditions in the European Modular Cultivation System on the International Space Station up to reproductive stage, and compare phenotypes on growth and development. We will also analyze cell wall properties and gene expression levels using collected materials. However, the amounts of materials collected will be severely limited, and we should develop an efficient procedure for this space experiment. In the present study, we examined the possibility of analyzing various parameters successively using the identical material. On orbit, plant materials will be fixed with RNAlater solution, kept at 4° C for several days and then frozen in a freezer at -20° C. We first examined whether the cell wall extensibility of inflorescence stems can be measured after RNAlater fixation. The gradient of the cell wall extensibility along inflorescence stems was detected in RNAlater-fixed materials as in methanol-killed ones. The sufficient amounts of RNA to analyze the gene expression were also obtained from the materials after measurement of the cell wall extensibility. Furthermore, the levels and composition of cell wall polysaccharides could be measured using the materials after extraction of RNA. These results show that we can analyze the physical and chemical properties of the cell wall as well as gene expression using the identical material obtained in the space experiments.

  4. Imaging hydraulic fractures at Median Tectonic Line, Japan using multiply generated and scattered tube waves in a shallow VSP experiment

    NASA Astrophysics Data System (ADS)

    Minato, Shohei; Ghose, Ranajit; Tsuji, Takeshi; Ikeda, Michiharu; Onishi, Kozo

    2016-04-01

    Tube waves are low frequency guided waves that propagate along a fluid-filled borehole. The analysis of tube waves is a promising approach to image and characterize hydraulic fractures intersecting a borehole. It exploits tube waves generated by an external seismic wavefield which compresses fractures and injects fluid into the borehole. It also utilizes the attenuation of tube waves due to fluid exchange between the fracture and the borehole, which creates scattered waves (reflection and transmission). Conventional approaches consider tube waves due to a single fracture. However, when the spacing between multiple fractures is short relative to the wavelength of the tube waves, the generated and scattered tube waves interfere with each other, making it difficult to isolate the effect of a single fracture. The analysis of closely spaced fractures is important in highly fractured areas, such as a fault zone. In this study, we explore the possibility of prediction and utilization of generated and scattered tube waves due to multiple fractures. We derive a new integral equation of the full tube wavefield using 1D wavefield representation theory incorporating nonwelded interfaces. We adapt the recent developments in modeling tube wave generation/scattering at a fracture. In these models, a fracture is represented as a parallel wall or a thin poloelastic layer. This allowed us to consider the effects of a dynamic fracture aperture with fracture compliances and the permeability. The representation also leads to a new imaging method for the hydraulic fractures, using multiply-generated and scattered tube waves. This is achieved by applying an inverse operator to the observed tube waves, which focuses the tube waves to the depth where they are generated and/or scattered. The inverse operator is constructed by a tube wave Green's function with a known propagation velocity. The Median Tectonic Line (MTL) is the most significant fault in Japan, extending NE-SW for over 1000 km

  5. Post-fracture management of patients with hip fracture: a perspective.

    PubMed

    Bruyere, O; Brandi, M-L; Burlet, N; Harvey, N; Lyritis, G; Minne, H; Boonen, S; Reginster, J-Y; Rizzoli, R; Akesson, K

    2008-10-01

    Hip fracture creates a worldwide morbidity, mortality and economic burden. After surgery, many patients experience long-term disability or die as a consequence of the fracture. A fracture is a major risk factor for a subsequent fracture, which may occur within a short interval. A literature search on post-fracture management of patients with hip fracture was performed on the Medline database. Key experts convened to develop a consensus document. Management of hip-fracture patients to optimize outcome after hospital discharge requires several stages of care co-ordinated by a multidisciplinary team from before admission through to discharge. Further studies that specifically assess prevention and post-fracture management of hip fracture are needed, as only one study to date has assessed an osteoporosis medication in patients with a recent hip fracture. Proper nutrition is vital to assist bone repair and prevent further falls, particularly in malnourished patients. Vitamin D, calcium and protein supplementation is associated with an increase in hip BMD and reduction in falls. Rehabilitation is essential to improve functional disabilities and survival rates. Fall prevention and functional recovery strategies should include patient education and training to improve balance and increase muscle strength and mobility. Appropriate management can prevent further fractures and it is critical that high-risk patients are identified and treated. To foster this process, clinical pathways have been established to support orthopaedic surgeons. Although hip fracture is generally associated with poor outcomes, appropriate management can ensure optimal recovery and survival, and should be prioritized after a hip fracture to avoid deterioration of health and prevent subsequent fracture.

  6. Infrared monitoring of hydrothermal echanges occurring in a fracture

    NASA Astrophysics Data System (ADS)

    Neuville, Amélie; Flekkøy, Eirik; Galland, Olivier; Gundersen, Olav; Jørgen Måløy, Knut

    2014-05-01

    We aim to characterize the heat exchange that occurs when water flows through a fracture at a different temperature from that of the surrounding rock. This happens during many man-made or natural processes. For instance, injection of water in the context of geothermal power plants or sudden mechanical movements (e.g. rockfalls, landslides, earthquakes) that transport water. It is presently challenging to estimate the heat transfer and temperature inside a fractured medium where water is flowing, despite various numerical models which have been proposed [Neuville et al, 2010, 2013; Kolditz et Clauser, 1998; Heuer, 1991]. The difficulties arise from the complexity of the fracture network, the fracture topography, as well as complex hydraulic flow (e.g. recirculation) and heat exchanges. As a consequence, various hypotheses were made in the models. More experimental data are required in order to calibrate these models, validate or refute the hypotheses. Our work aims to provide temperature data at the fracture scale, in an experiment where the pressure gradient an fracture topography are controlled, with slow hydraulic flow. This required to develop a setup from scratch. An infrared camera and thermistors are used to monitor the temperature in space and time. Water is injected through a partly natural rough fracture with impermeable walls. The bottom part of the fracture is a larvikite stone with a rough surface (presumably this surface was obtained from mode I fracturing), and the top part is a layer which is transparent in the infrared range. As a consequence the infrared camera is expected to measure the temperature at the interface between this transparent layer and the water. The topography of the surface of the rock was reconstituted using a photogrammetry software [MicMac, IGN], and compared to measurements made with a mechanical profiler. Using this geometry we carefully localize the temperature observations (infrared camera and thermistors) and correlate the

  7. Facial Fractures.

    PubMed

    Ghosh, Rajarshi; Gopalkrishnan, Kulandaswamy

    2018-06-01

    The aim of this study is to retrospectively analyze the incidence of facial fractures along with age, gender predilection, etiology, commonest site, associated dental injuries, and any complications of patients operated in Craniofacial Unit of SDM College of Dental Sciences and Hospital. This retrospective study was conducted at the Department of OMFS, SDM College of Dental Sciences, Dharwad from January 2003 to December 2013. Data were recorded for the cause of injury, age and gender distribution, frequency and type of injury, localization and frequency of soft tissue injuries, dentoalveolar trauma, facial bone fractures, complications, concomitant injuries, and different treatment protocols.All the data were analyzed using statistical analysis that is chi-squared test. A total of 1146 patients reported at our unit with facial fractures during these 10 years. Males accounted for a higher frequency of facial fractures (88.8%). Mandible was the commonest bone to be fractured among all the facial bones (71.2%). Maxillary central incisors were the most common teeth to be injured (33.8%) and avulsion was the most common type of injury (44.6%). Commonest postoperative complication was plate infection (11%) leading to plate removal. Other injuries associated with facial fractures were rib fractures, head injuries, upper and lower limb fractures, etc., among these rib fractures were seen most frequently (21.6%). This study was performed to compare the different etiologic factors leading to diverse facial fracture patterns. By statistical analysis of this record the authors come to know about the relationship of facial fractures with gender, age, associated comorbidities, etc.

  8. [Chronic chest pain after rib fracture: It can cause a disability?

    PubMed

    Rabiou, S; Ouadnouni, Y; Lakranbi, M; Traibi, A; Antoini, F; Smahi, M

    2018-04-01

    The rib fractures and instability of the chest wall are the main lesions of closed chest trauma. These lesions can be a source of chronic, often disabling with daily discomfort resulting limitation of some activities. The objective of this study was to assess the prevalence of this phenomenon in order to improve the quality of early care. Through an observational retrospective cohort study on a number of 41 patients supported and monitored for traumatic rib fractures at the Military Hospital of Meknes during the period from October 2010 to March 2016. The circumstances of the accident were dominated by accidents of public roads (86%) and concerned the young adult male. Radiographs have enumerated 165 fracture lines with an average of 4 rib fractures per patient. These were unilateral fractures in 88% of cases, and concerned the means arc in 46% of cases. The rib fracture was undisplaced fracture in 39% of patients, whereas in 2 patients, a flail chest was present. Post-traumatic hemothorax (63% of cases) were the thoracic lesions most commonly associated with rib fractures. The initial management consisted in the use of analgesics systemically in all patients. The retrospective evaluation of pain by the verbal scale was possible in 30 patients. The persistent pain was noted in 60% of cases. This pain was triggered by a simple effort to moderate in 55% of cases, and hard effort in 28% of cases. In 17% of patients, even at rest, the pain occurred intermittently. The impact in terms of disability was mild to moderate in 28% of cases and important in 17%. The neuropathic pain was found in 3 patients. Therapeutically, the first and second levels of analgesics were sufficient to relieve pain. The neuroleptics were required for 2 patients. Our study confirms the persistence of chronic painful, sometimes lasting several years after the initial chest trauma. This pain is responsible of disability triggered most often after exercise. Copyright © 2017 Elsevier Masson

  9. The second fracture of the same clavicle: prevalence and fracture configurations.

    PubMed

    Asavamongkolkul, Apichat; Harnroongroj, Thos; Suteeraporn, Wuttipon; Sudjai, Narumol; Harnroongroj, Thossart

    2012-12-01

    To study second fracture at the same clavicle including prevalence, fracture configurations related to malunion types of the first fracture, and healing. Between 2008 and 2011, the authors reviewed medical records and radiographs of the clavicles of patients who sustained acute clavicular fractures from motorcycle accident. Second fracture at the same clavicle and prevalence were studied. Malunion of the first fracture of the same clavicle were typed and configurations of the second fracture at the same clavicles were described related to type of the malunion. There were 552 clavicular fractures. Four cases of which sustained a second fracture at the same clavicles. Malunion of the first clavicular fracture of the four cases were typed: type I, extension, type II, flexion, and type III, bayonet. There were one, two, and one case of second clavicular fractures of the type I, II, and III clavicular malunion. The configuration of second clavicular fracture of the type I malunion clavicle is located at lateral fragment, inferior displacement, and dorsal angulation with dorsal cortex conminution. The type II malunion clavicle is located at lateral fragment with minimal displacement. For the type III malunion clavicle, the second fracture is located at medial fragment with mild inferior displacement and inferior angulation. The four cases of the second fractures of the same clavicles healed within two months without complication. The prevalence of second fracture at the same clacicles was 7.2:1000. The three types of the first fracture malunion were extension, flexion, and bayonet. The configuration of the second fracture at the same clavicles depends on malunion types of the first clavicular fracture. They healed without complication.

  10. Rehabilitation of orbital cavity after orbital exenteration using polymethyl methacrylate orbital prosthesis.

    PubMed

    Jain, Sumeet; Jain, Parul

    2016-01-01

    Squamous cell carcinoma of the eyelid is the second most common malignant neoplasm of the eye with the incidence of 0.09 and 2.42 cases/100 000 people. Orbital invasion is a rare complication but, if recognized early, can be treated effectively with exenteration. Although with advancements in technology such as computer-aided design and computer-aided manufacturing, material science, and retentive methods like implants, orbital prosthesis with stock ocular prosthesis made of methyl methacrylate retained by anatomic undercuts is quiet effective and should not be overlooked and forgotten. This clinical report describes prosthetic rehabilitation of two male patients with polymethyl methacrylate resin orbital prosthesis after orbital exenteration, for squamous cell carcinoma of the upper eyelid. The orbital prosthesis was sufficiently retained by hard and soft tissue undercuts without any complications. The patients using the prosthesis are quite satisfied with the cosmetic results and felt comfortable attending the social events.

  11. PREFACE: Domain wall dynamics in nanostructures Domain wall dynamics in nanostructures

    NASA Astrophysics Data System (ADS)

    Marrows, C. H.; Meier, G.

    2012-01-01

    spin-transfer torque threshold current density in coupled vortex domain wallsS Lepadatu, A P Mihai, J S Claydon, F Maccherozzi, S S Dhesi, C J Kinane, S Langridge and C H Marrows Large RF susceptibility of transverse domain wallsO Rousseau, S Petit-Watelot and M Viret Expansion and relaxation of magnetic mirror domains in a Pt/Co/Pt/Co/Pt multilayer with antiferromagnetic interlayer couplingP J Metaxas, R L Stamps, J-P Jamet, J Ferré, V Baltz and B Rodmacq Current-induced domain wall motion and magnetization dynamics in CoFeB/Cu/Co nanostripesV Uhlíř, J Vogel, N Rougemaille, O Fruchart, Z Ishaque, V Cros, J Camarero, J C Cezar, F Sirotti and S Pizzini Roles of the magnetic field and electric current in thermally activated domain wall motion in a submicrometer magnetic strip with perpendicular magnetic anisotropySatoru Emori and Geoffrey S D Beach Electrical domain morphologies in compositionally graded ferroelectric filmsM B Okatan, A L Roytburd, V Nagarajan and S P Alpay Domain-wall pinning by local control of anisotropy in Pt/Co/Pt strips J H Franken, M Hoeijmakers, R Lavrijsen and H J M Swagten Experimental detection of domain wall propagation above the Walker field Kouta Kondou, Norikazu Ohshima, Daichi Chiba, Shinya Kasai, Kensuke Kobayashi and Teruo Ono Enhanced functionality in magnonics by domain walls and inhomogeneous spin configurationsG Duerr, R Huber and D Grundler Domain wall motion in perpendicular anisotropy nanowires with edge roughness Maximilian Albert, Matteo Franchin, Thomas Fischbacher, Guido Meier and Hans Fangohr Determination of the spin torque non-adiabaticity in perpendicularly magnetized nanowiresJ Heinen, D Hinzke, O Boulle, G Malinowski, H J M Swagten, B Koopmans, C Ulysse, G Faini, B Ocker, J Wrona and M Kläui Domain wall dynamics driven by spin transfer torque and the spin-orbit field Masamitsu Hayashi, Yoshinobu Nakatani, Shunsuke Fukami, Michihiko Yamanouchi, Seiji Mitani and Hideo Ohno Dynamic propagation and nucleation in domain

  12. Occult Intertrochanteric Fracture Mimicking the Fracture of Greater Trochanter.

    PubMed

    Chung, Phil Hyun; Kang, Suk; Kim, Jong Pil; Kim, Young Sung; Lee, Ho Min; Back, In Hwa; Eom, Kyeong Soo

    2016-06-01

    Occult intertrochanteric fractures are misdiagnosed as isolated greater trochanteric fractures in some cases. We investigated the utility of three-dimensional computed tomography (3D-CT) and magnetic resonance imaging (MRI) in the diagnosis and outcome management of occult intertrochanteric fractures. This study involved 23 cases of greater trochanteric fractures as diagnosed using plain radiographs from January 2004 to July 2013. Until January 2008, 9 cases were examined with 3D-CT only, while 14 cases were screened with both 3D-CT and MRI scans. We analyzed diagnostic accuracy and treatment results following 3D-CT and MRI scanning. Nine cases that underwent 3D-CT only were diagnosed with isolated greater trochanteric fractures without occult intertrochanteric fractures. Of these, a patient with displacement received surgical treatment. Of the 14 patients screened using both CT and MRI, 13 were diagnosed with occult intertrochanteric fractures. Of these, 11 were treated with surgical intervention and 2 with conservative management. Three-dimensional CT has very low diagnostic accuracy in diagnosing occult intertrochanteric fractures. For this reason, MRI is recommended to confirm a suspected occult intertrochanteric fracture and to determine the most appropriate mode of treatment.

  13. Altered-stress fracturing

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

    Warpinski, N.R.; Branagan, P.T.

    Altered-stress fracturing is a concept whereby a hydraulic fracture in one well is reoriented by another hydraulic fracture in a nearby location. The application is in tight, naturally fractured, anisotropic reservoirs in which conventional hydraulic fractures parallel the highly permeable natural fractures and little production enhancement is achieved by conventional hydraulic fracturing. Altered-stress fracturing can modify the stress field so that hydraulic fractures propagate across the permeable natural fractures. A field test was conducted in which stress changes of 250 to 300 psi (1.7 to 2.1 MPa) were measured in an offset well 120 ft (37 m) away during relativelymore » small minifracs in a production well. These results show that stress-altered fracturing is possible at this site and others. Analytic and finite element calculations quantify the effects of layers, stresses, and crack size. Reservoir calculations show significant enhancement compared to conventional treatments. 21 refs., 12 figs., 3 tabs.« less

  14. Pediatric Facial Fractures: A Review of 2071 Fractures.

    PubMed

    Ferreira, Pedro Costa; Barbosa, Joselina; Braga, José Miguel; Rodrigues, Acácio; Silva, Álvaro Catarino; Amarante, José Manuel

    2016-01-01

    Facial fractures are infrequent in children and adolescents, and there are only few reports that review a significant number of patients. The objective of this study was to analyze the pattern of maxillofacial fractures in pediatric patients of Portugal. We reviewed the clinical records of a series of 1416 patients 18 years or younger with facial fractures, treated by the Department of Plastic Reconstructive, Aesthetic and of Maxillofacial Surgery of São João Hospital, Porto, Portugal, between 1993 and 2012. The following parameters were evaluated: age; sex; cause of the accident; hour, day, and month of hospital admission; location and type of fractures; presence and location of associated injuries; treatment methods; length of in-hospital stay; and complications. A total of 2071 fractures were treated. The ratio of boys to girls was 3.1:1. Patients between 16 and 18 years old were the major group (43.9%). Motor vehicle accident was the most common cause of injuries (48.7% of patients). Mandibular fractures were the most common (44.4%). Associated injuries occurred in 1015 patients (71.7%). Pediatric facial fractures are usually associated with severe trauma. There has been a highly significant decrease (P < 0.001) in pediatric facial fractures in Portugal for the past 20 years.

  15. Propagation and transmission of optical vortex beams through turbid scattering wall with orbital angular momentums

    NASA Astrophysics Data System (ADS)

    Wang, W. B.; Gozali, Richard; Nguyen, Thien An; Alfano, R. R.

    2015-03-01

    Light scattering and transmission of optical Laguerre Gaussian (LG) vortex beams with different orbital angular momentum (OAM) states in turbid scattering media were investigated in comparison with Gaussian (G) beam. The scattering media used in the experiments consist of various sizes and concentrations of latex beads in water solutions. The LG beams were generated using a spatial light modulator in reflection mode. The ballistic transmissions of LG and G beams were measured with different ratios of thickness of samples (z) to scattering mean free path (ls) of the turbid media, z/ls. The results show that in the ballistic region where z/ls is small, the LG and G beams show no significant difference, while in the diffusive region where z/ls is large, LG beams show higher transmission than Gaussian beam. In the diffusive region, the LG beams with higher orbital angular momentum L values show higher transmission than the beams with lower L values. The transition points from ballistic to diffusive regions for different scattering media were studied and determined.

  16. A Rare Entity: Bilateral First Rib Fractures Accompanying Bilateral Scapular Fractures.

    PubMed

    Gulbahar, Gultekin; Kaplan, Tevfik; Turker, Hasan Bozkurt; Gundogdu, Ahmet Gokhan; Han, Serdar

    2015-01-01

    First rib fractures are scarce due to their well-protected anatomic locations. Bilateral first rib fractures accompanying bilateral scapular fractures are very rare, although they may be together with scapular and clavicular fractures. According to our knowledge, no case of bilateral first rib fractures accompanying bilateral scapular fractures has been reported, so we herein discussed the diagnosis, treatment, and complications of bone fractures due to thoracic trauma in bias of this rare entity.

  17. A Rare Entity: Bilateral First Rib Fractures Accompanying Bilateral Scapular Fractures

    PubMed Central

    Gulbahar, Gultekin; Kaplan, Tevfik; Turker, Hasan Bozkurt; Gundogdu, Ahmet Gokhan; Han, Serdar

    2015-01-01

    First rib fractures are scarce due to their well-protected anatomic locations. Bilateral first rib fractures accompanying bilateral scapular fractures are very rare, although they may be together with scapular and clavicular fractures. According to our knowledge, no case of bilateral first rib fractures accompanying bilateral scapular fractures has been reported, so we herein discussed the diagnosis, treatment, and complications of bone fractures due to thoracic trauma in bias of this rare entity. PMID:26175916

  18. Enhancement of Fracture Toughness of Epoxy Nanocomposites by Combining Nanotubes and Nanosheets as Fillers

    PubMed Central

    Domun, Nadiim; Paton, Keith R.; Sainsbury, Toby; Zhang, Tao; Mohamud, Hibaaq

    2017-01-01

    In this work the fracture toughness of epoxy resin has been improved through the addition of low loading of single part and hybrid nanofiller materials. Functionalised multi-walled carbon nanotubes (f-MWCNTs) was used as single filler, increased the critical strain energy release rate, GIC, by 57% compared to the neat epoxy, at only 0.1 wt% filler content. Importantly, no degradation in the tensile or thermal properties of the nanocomposite was observed compared to the neat epoxy. When two-dimensional boron nitride nanosheets (BNNS) were added along with the one-dimensional f-MWCNTs, the fracture toughness increased further to 71.6% higher than that of the neat epoxy. Interestingly, when functionalised graphene nanoplatelets (f-GNPs) and boron nitride nanotubes (BNNTs) were used as hybrid filler, the fracture toughness of neat epoxy is improved by 91.9%. In neither of these hybrid filler systems the tensile properties were degraded, but the thermal properties of the nanocomposites containing boron nitride materials deteriorated slightly. PMID:29048345

  19. Enhancement of Fracture Toughness of Epoxy Nanocomposites by Combining Nanotubes and Nanosheets as Fillers.

    PubMed

    Domun, Nadiim; Paton, Keith R; Hadavinia, Homayoun; Sainsbury, Toby; Zhang, Tao; Mohamud, Hibaaq

    2017-10-19

    In this work the fracture toughness of epoxy resin has been improved through the addition of low loading of single part and hybrid nanofiller materials. Functionalised multi-walled carbon nanotubes (f-MWCNTs) was used as single filler, increased the critical strain energy release rate, G IC , by 57% compared to the neat epoxy, at only 0.1 wt% filler content. Importantly, no degradation in the tensile or thermal properties of the nanocomposite was observed compared to the neat epoxy. When two-dimensional boron nitride nanosheets (BNNS) were added along with the one-dimensional f-MWCNTs, the fracture toughness increased further to 71.6% higher than that of the neat epoxy. Interestingly, when functionalised graphene nanoplatelets (f-GNPs) and boron nitride nanotubes (BNNTs) were used as hybrid filler, the fracture toughness of neat epoxy is improved by 91.9%. In neither of these hybrid filler systems the tensile properties were degraded, but the thermal properties of the nanocomposites containing boron nitride materials deteriorated slightly.

  20. Use of advanced borehole geophysical techniques to delineate fractured-rock ground-water flow and fractures along water-tunnel facilities in northern Queens County, New York

    USGS Publications Warehouse

    Stumm, Frederick; Chu, Anthony; Lange, Andrew D.; Paillet, Frederick L.; Williams, John H.; Lane, John W.

    2001-01-01

    Advanced borehole geophysical methods were used to assess the geohydrology of crystalline bedrock along the course of a new water tunnel for New York City. The logging methods include natural gamma, spontaneous potential, single-point resistance, mechanical and acoustic caliper, focused electromagnetic induction, electromagnetic resistivity, magnetic susceptibility, borehole-fluid temperature and conductance, differential temperature, heat-pulse flowmeter, acoustic televiewer, borehole deviation, optical televiewer, and borehole radar. Integrated interpretation of the geophysical logs from an 825-foot borehole (1) provided information on the extent, orientation, and structure (foliation and fractures) within the entire borehole, including intensely fractured intervals from which core recovery may be poor; (2) delineated transmissive fracture zones intersected by the borehole and provided estimates of their transmissivity and hydraulic head; and (3) enabled mapping of the location and orientation of structures at distances as much as 100 ft from the borehole.Analyses of the borehole-wall image and the geophysical logs from the borehole on Crescent Street, in northern Queens County, are presented here to illustrate the application of the methods. The borehole penetrates gneiss and other crystalline bedrock that has predominantly southeastward dipping foliation and nearly horizontal and southeastward-dipping fractures. The heat-pulse flowmeter logs obtained under pumping and nonpumping conditions, together with the other geophysical logs, indicate five transmissive fracture zones. More than 90 percent of the open-hole transmissivity is associated with a fracture zone 272 feet BLS (below land surface). A transmissive zone at 787 feet BLS that consists of nearly parallel fractures lies within the projected tunnel path; here the hydraulic head is 12 to 15 feet lower than that of transmissive zones above the 315-foot depth. The 60-megahertz directional borehole radar logs

  1. Cell-wall recovery after irreversible deformation of wood

    NASA Astrophysics Data System (ADS)

    Keckes, Jozef; Burgert, Ingo; Frühmann, Klaus; Müller, Martin; Kölln, Klaas; Hamilton, Myles; Burghammer, Manfred; Roth, Stephan V.; Stanzl-Tschegg, Stefanie; Fratzl, Peter

    2003-12-01

    The remarkable mechanical properties of biological materials reside in their complex hierarchical architecture and in specific molecular mechanistic phenomena. The fundamental importance of molecular interactions and bond recovery has been suggested by studies on deformation and fracture of bone and nacre. Like these mineral-based materials, wood also represents a complex nanocomposite with excellent mechanical performance, despite the fact that it is mainly based on polymers. In wood, however, the mechanistic contribution of processes in the cell wall is not fully understood. Here we have combined tensile tests on individual wood cells and on wood foils with simultaneous synchrotron X-ray diffraction analysis in order to separate deformation mechanisms inside the cell wall from those mediated by cell-cell interactions. We show that tensile deformation beyond the yield point does not deteriorate the stiffness of either individual cells or foils. This indicates that there is a dominant recovery mechanism that re-forms the amorphous matrix between the cellulose microfibrils within the cell wall, maintaining its mechanical properties. This stick-slip mechanism, rather like Velcro operating at the nanometre level, provides a 'plastic response' similar to that effected by moving dislocations in metals. We suggest that the molecular recovery mechanism in the cell matrix is a universal phenomenon dominating the tensile deformation of different wood tissue types.

  2. Operative treatment of intra-articular calcaneal fractures with calcaneal plates and its complications

    PubMed Central

    Rak, Vaclav; Ira, Daniel; Masek, Michal

    2009-01-01

    Background: In a retrospective study we analysed intra-articular calcaneal fracture treatment by comparing results and complications related to fracture stabilization with nonlocking calcaneal plates and locking compression plates. Materials and Methods: We performed 76 osteosynthesis (67 patients) of intra-articular calcaneal fractures using the standard extended lateral approach from February 2004 to October 2007. Forty-two operations using nonlocking calcaneal plates (group A) were performed during the first three years, and 34 calcaneal fractures were stabilized using locking compression plates (group B) in 2007. In the Sanders type IV fractures, reconstruction of the calcaneal shape was attempted. Depending on the type of late complication, we performed subtalar arthroscopy in six cases, arthroscopically assisted subtalar distraction bone block arthrodesis in six cases, and plate removal with lateral-wall decompression in five cases. The patients were evaluated by the AOFAS Ankle-Hindfoot Scale. Results: Wound healing complications were 7/42 (17%) in group A and 1/34 (3%) in group B. No patient had deep osseous infection or foot rebound compartment syndrome. Preoperative size of Böhler's angle correlated with postoperative clinical results in both groups. There were no late complications necessitating corrective procedure or arthroscopy until December 2008 in Group B. All late complications ccurred in Group A. The overall results according to the AOFAS Ankle Hindfoot Scale were good or excellent in 23/42 (55%) in group A and in 30/34 (85%) in group B. Conclusion: Open reduction and internal fixation of intra-articular calcaneal fractures has become a standard surgical method. Fewer complications and better results related to treatment with locking compression plates confirmed in comparison to nonlocking ones were noted for all Sanders types of intra-articular calcaneal fractures. Age and Sanders type IV fractures are not considered to be the contraindications

  3. A Near-Wall Reynolds-Stress Closure Without Wall Normals

    NASA Technical Reports Server (NTRS)

    Yuan, S. P.; So, R. M. C.

    1997-01-01

    Turbulent wall-bounded complex flows are commonly encountered in engineering practice and are of considerable interest in a variety of industrial applications. The presence of a wall significantly affects turbulence characteristics. In addition to the wall effects, turbulent wall-bounded flows become more complicated by the presence of additional body forces (e.g. centrifugal force and Coriolis force) and complex geometry. Most near-wall Reynolds stress models are developed from a high-Reynolds-number model which assumes turbulence is homogenous (or quasi-homogenous). Near-wall modifications are proposed to include wall effects in near-wall regions. In this process, wall normals are introduced. Good predictions could be obtained by Reynolds stress models with wall normals. However, ambiguity arises when the models are applied in flows with multiple walls. Many models have been proposed to model turbulent flows. Among them, Reynolds stress models, in which turbulent stresses are obtained by solving the Reynolds stress transport equations, have been proved to be the most successful ones. To apply the Reynolds stress models to wall-bounded flows, near-wall corrections accounting for the wall effects are needed, and the resulting models are called near-wall Reynolds stress models. In most of the existing near-wall models, the near-wall corrections invoke wall normals. These wall-dependent near-wall models are difficult to implement for turbulent flows with complex geometry and may give inaccurate predictions due to the ambiguity of wall normals at corners connecting multiple walls. The objective of this study is to develop a more general and flexible near-wall Reynolds stress model without using any wall-dependent variable for wall-bounded turbulent flows. With the aid of near-wall asymptotic analysis and results of direct numerical simulation, a new near-wall Reynolds stress model (NNWRS) is formulated based on Speziale et al.'s high-Reynolds-stress model with wall

  4. Relationships between fractures

    NASA Astrophysics Data System (ADS)

    Peacock, D. C. P.; Sanderson, D. J.; Rotevatn, A.

    2018-01-01

    Fracture systems comprise many fractures that may be grouped into sets based on their orientation, type and relative age. The fractures are often arranged in a network that involves fracture branches that interact with one another. Interacting fractures are termed geometrically coupled when they share an intersection line and/or kinematically coupled when the displacements, stresses and strains of one fracture influences those of the other. Fracture interactions are characterised in terms of the following. 1) Fracture type: for example, whether they have opening (e.g., joints, veins, dykes), closing (stylolites, compaction bands), shearing (e.g., faults, deformation bands) or mixed-mode displacements. 2) Geometry (e.g., relative orientations) and topology (the arrangement of the fractures, including their connectivity). 3) Chronology: the relative ages of the fractures. 4) Kinematics: the displacement distributions of the interacting fractures. It is also suggested that interaction can be characterised in terms of mechanics, e.g., the effects of the interaction on the stress field. It is insufficient to describe only the components of a fracture network, with fuller understanding coming from determining the interactions between the different components of the network.

  5. Variation in Treatment of Displaced Geriatric Acetabular Fractures Among 15 Level-I Trauma Centers.

    PubMed

    Manson, Theodore T; Reider, Lisa; OʼToole, Robert V; Scharfstein, Daniel O; Tornetta, Paul; Gary, Joshua L

    2016-09-01

    To document the initial treatment of displaced acetabular fractures among older adults across multiple trauma centers and to investigate the factors that influence the decision to operate and the choice of operative procedure [open reduction internal fixation (ORIF) vs. total hip arthroplasty (THA)]. Retrospective observational study. Fifteen US level-I trauma centers participating in the Major Extremity Trauma Research Consortium. Overall, 269 patients aged 60 years or older admitted for the treatment of a displaced acetabular fracture. None. Treatment. Sixty percent of fractures (n = 162) were treated operatively. Younger age (<80 years), injury from high-energy mechanism, fractures with femoral head impaction, and fractures without hip congruency were significantly associated with receiving operative treatment (P < 0.05). Significant site variation in operative versus nonoperative treatment occurred even after accounting for these factors (P = 0.0044). Among operatively treated patients, 88% (n = 142) received ORIF and 12% (n = 20) received THA as the initial treatment. Women were more likely to be treated with initial THA compared with men; of the known risk factors for poor outcomes with ORIF (ie, dome or roof impaction, femoral head impaction, or posterior wall involvement), only dome impaction was significantly associated with receiving initial THA (P < 0.05). Currently, no treatment guidelines exist for acetabular fractures in older adults, which likely explains the significant site variation in operative versus nonoperative treatment. This study identifies patient and injury factors that drive treatment decisions, which will be important in planning and designing future trials needed to determine the best treatment for these fractures.

  6. Proximal femoral fractures.

    PubMed

    Webb, Lawrence X

    2002-01-01

    Fractures of the proximal femur include fractures of the head, neck, intertrochanteric, and subtrochanteric regions. Head fractures commonly accompany dislocations. Neck fractures and intertrochanteric fractures occur with greatest frequency in elderly patients with a low bone mineral density and are produced by low-energy mechanisms. Subtrochanteric fractures occur in a predominantly strong cortical osseous region which is exposed to large compressive stresses. Implants used to address these fractures must be able to accommodate significant loads while the fractures consolidate. Complications secondary to these injuries produce significant morbidity and include infection, nonunion, malunion, decubitus ulcers, fat emboli, deep venous thrombosis, pulmonary embolus, pneumonia, myocardial infarction, stroke, and death.

  7. Fracture mechanisms and fracture control in composite structures

    NASA Astrophysics Data System (ADS)

    Kim, Wone-Chul

    Four basic failure modes--delamination, delamination buckling of composite sandwich panels, first-ply failure in cross-ply laminates, and compression failure--are analyzed using linear elastic fracture mechanics (LEFM) and the J-integral method. Structural failures, including those at the micromechanical level, are investigated with the aid of the models developed, and the critical strains for crack propagation for each mode are obtained. In the structural fracture analyses area, the fracture control schemes for delamination in a composite rib stiffener and delamination buckling in composite sandwich panels subjected to in-plane compression are determined. The critical fracture strains were predicted with the aid of LEFM for delamination and the J-integral method for delamination buckling. The use of toughened matrix systems has been recommended for improved damage tolerant design for delamination crack propagation. An experimental study was conducted to determine the onset of delamination buckling in composite sandwich panel containing flaws. The critical fracture loads computed using the proposed theoretical model and a numerical computational scheme closely followed the experimental measurements made on sandwich panel specimens of graphite/epoxy faceskins and aluminum honeycomb core with varying faceskin thicknesses and core sizes. Micromechanical models of fracture in composites are explored to predict transverse cracking of cross-ply laminates and compression fracture of unidirectional composites. A modified shear lag model which takes into account the important role of interlaminar shear zones between the 0 degree and 90 degree piles in cross-ply laminate is proposed and criteria for transverse cracking have been developed. For compressive failure of unidirectional composites, pre-existing defects play an important role. Using anisotropic elasticity, the stress state around a defect under a remotely applied compressive load is obtained. The experimentally

  8. Multifocal humeral fractures.

    PubMed

    Maresca, A; Pascarella, R; Bettuzzi, C; Amendola, L; Politano, R; Fantasia, R; Del Torto, M

    2014-02-01

    Multifocal humeral fractures are extremely rare. These may affect the neck and the shaft, the shaft alone, or the diaphysis and the distal humerus. There is no classification of these fractures in the literature. From 2004 to 2010, 717 patients with humeral fracture were treated surgically at our department. Thirty-five patients presented with an associated fracture of the proximal and diaphyseal humerus: synthesis was performed with plate and screws in 34 patients, and the remaining patient had an open fracture that was treated with an external fixator. Mean follow-up was 3 years and 3 months. A classification is proposed in which type A fractures are those affecting the proximal and the humeral shaft, type B the diaphysis alone, and type C the diaphysis in association with the distal humerus. Type A fractures are then divided into three subgroups: A-I, undisplaced fracture of the proximal humerus and displaced shaft fracture; A-II: displaced fracture of the proximal and humeral shaft; and A-III: multifragmentary fracture affecting the proximal humerus and extending to the diaphysis. Multifocal humeral fractures are very rare and little described in the literature, both for classification and treatment. The AO classification describes bifocal fracture of the humeral diaphysis, type B and C. The classification suggested in this article mainly concerns fractures involving the proximal and humeral shaft. A simple classification of multifocal fractures is suggested to help the surgeon choose the most suitable type of synthesis for surgical treatment. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Occult Intertrochanteric Fracture Mimicking the Fracture of Greater Trochanter

    PubMed Central

    Chung, Phil Hyun; Kang, Suk; Kim, Jong Pil; Kim, Young Sung; Back, In Hwa; Eom, Kyeong Soo

    2016-01-01

    Purpose Occult intertrochanteric fractures are misdiagnosed as isolated greater trochanteric fractures in some cases. We investigated the utility of three-dimensional computed tomography (3D-CT) and magnetic resonance imaging (MRI) in the diagnosis and outcome management of occult intertrochanteric fractures. Materials and Methods This study involved 23 cases of greater trochanteric fractures as diagnosed using plain radiographs from January 2004 to July 2013. Until January 2008, 9 cases were examined with 3D-CT only, while 14 cases were screened with both 3D-CT and MRI scans. We analyzed diagnostic accuracy and treatment results following 3D-CT and MRI scanning. Results Nine cases that underwent 3D-CT only were diagnosed with isolated greater trochanteric fractures without occult intertrochanteric fractures. Of these, a patient with displacement received surgical treatment. Of the 14 patients screened using both CT and MRI, 13 were diagnosed with occult intertrochanteric fractures. Of these, 11 were treated with surgical intervention and 2 with conservative management. Conclusion Three-dimensional CT has very low diagnostic accuracy in diagnosing occult intertrochanteric fractures. For this reason, MRI is recommended to confirm a suspected occult intertrochanteric fracture and to determine the most appropriate mode of treatment. PMID:27536653

  10. Effects of Atomic-Scale Structure on the Fracture Properties of Amorphous Carbon - Carbon Nanotube Composites

    NASA Technical Reports Server (NTRS)

    Jensen, Benjamin D.; Wise, Kristopher E.; Odegard, Gregory M.

    2015-01-01

    The fracture of carbon materials is a complex process, the understanding of which is critical to the development of next generation high performance materials. While quantum mechanical (QM) calculations are the most accurate way to model fracture, the fracture behavior of many carbon-based composite engineering materials, such as carbon nanotube (CNT) composites, is a multi-scale process that occurs on time and length scales beyond the practical limitations of QM methods. The Reax Force Field (ReaxFF) is capable of predicting mechanical properties involving strong deformation, bond breaking and bond formation in the classical molecular dynamics framework. This has been achieved by adding to the potential energy function a bond-order term that varies continuously with distance. The use of an empirical bond order potential, such as ReaxFF, enables the simulation of failure in molecular systems that are several orders of magnitude larger than would be possible in QM techniques. In this work, the fracture behavior of an amorphous carbon (AC) matrix reinforced with CNTs was modeled using molecular dynamics with the ReaxFF reactive forcefield. Care was taken to select the appropriate simulation parameters, which can be different from those required when using traditional fixed-bond force fields. The effect of CNT arrangement was investigated with three systems: a single-wall nanotube (SWNT) array, a multi-wall nanotube (MWNT) array, and a SWNT bundle system. For each arrangement, covalent bonds are added between the CNTs and AC, with crosslink fractions ranging from 0-25% of the interfacial CNT atoms. The SWNT and MWNT array systems represent ideal cases with evenly spaced CNTs; the SWNT bundle system represents a more realistic case because, in practice, van der Waals interactions lead to the agglomeration of CNTs into bundles. The simulation results will serve as guidance in setting experimental processing conditions to optimize the mechanical properties of CNT

  11. Pseudo-Duane's retraction syndrome.

    PubMed Central

    Duane, T D; Schatz, N J; Caputo, A R

    1976-01-01

    Five patients presented with signs that were similar to but opposite from Duane's retraction syndrome. Most had a history of orbital trauma. On attempted abduction a narrowing of the palpebral fissure and retraction of the globe was observed. Diplopia with lateral gaze was present. Roentgenograms (polytomograms) showed involvement of the medial orbital wall. Forced ductuin tests were positive. Surgical repair of the fracture and release of the entrapped muscle as determined by forced duction tests and by postoperative motility led to successful results. Images FIGURE 1 A FIGURE 1 B FIGURE 2 FIGURE 3 PMID:867622

  12. [One-stage operation for pelvis and acetabular fractures combined with Morel-Lavallée injury by internal fixation associated with vacuum sealing drainage].

    PubMed

    Wei, Dan; Wang, Yue; Yuan, Jiabin; Tang, Xiaoming; Zhang, Bin; Lu, Bing; Tan, Bo

    2014-01-01

    To investigate the methods and effectiveness of one-stage operation for pelvis and acetabular fractures combined with Morel-Lavallée injury by internal fixation associated with vacuum sealing drainage (VSD). Between June 2008 and October 2012, 15 cases of pelvis and acetabular fractures combined with Morel-Lavallée injury were treated. There were 5 males and 10 females, aged from 18 to 67 years (mean, 36.8 years). Fractures were caused by traffic accident in 11 cases and crashing injury of heavy object in 4 cases. The time from injury to hospitalization was 3 hours to 9 days (mean, 5.4 days). Morel-Lavallée injury located in the above posterior superior iliac spine in 4 cases, greater trochanter in 7 cases, and anterior proximal thigh in 4 cases. In 10 cases complicated by pelvic fracture, there were 1 case of anteroposterior compression type, 3 cases of lateral compression type, 5 cases of vertical shear type, and 1 case of compound injury type; in 5 cases complicated by acetabular fracture, there were 1 case of transverse fracture, 1 case of posterior wall and posterior column fracture, 1 case of transverse acetabulum plus posterior wall fracture, and 2 cases of both columns fracture. Open reduction and internal fixation were used to treat pelvic and acetabular fractures, and VSD to treat Morel-Lavallée injury. When the drainage volume was less than 20 mL/d, interrupted wound suture or free skin grafting was performed. The hospitalization time was 16-31 days (mean, 20.8 days). Thirteen cases were followed up 4-16 months (mean, 7.8 months). The healing time of Morel-Lavallée injury was 16-36 days after operation (mean, 21.3 days). All the wounds had primary healing, and no infection occurred. The X-ray films showed that all fractures healed, with a mean healing time of 13.6 weeks (range, 11-18 weeks). At 6.5 months after operation, according to Majeed function scoring system in 8 cases of pelvic fracture, the results were excellent in 5 cases, good in 2 cases

  13. Research on Crack Formation in Gypsum Partitions with Doorway by Means of FEM and Fracture Mechanics

    NASA Astrophysics Data System (ADS)

    Kania, Tomasz; Stawiski, Bohdan

    2017-10-01

    Cracking damage in non-loadbearing internal partition walls is a serious problem that frequently occurs in new buildings within the short term after putting them into service or even before completion of construction. Damage in partition walls is sometimes so great that they cannot be accepted by their occupiers. This problem was illustrated by the example of damage in a gypsum partition wall with doorway attributed to deflection of the slabs beneath and above it. In searching for the deflection which causes damage in masonry walls, fracture mechanics applied to the Finite Element Method (FEM) have been used. For a description of gypsum behaviour, the smeared cracking material model has been selected, where stresses are transferred across the narrowly opened crack until its width reaches the ultimate value. Cracks in the Finite Element models overlapped the real damage observed in the buildings. In order to avoid cracks under the deflection of large floor slabs, the model of a wall with reinforcement in the doorstep zone and a 40 mm thick elastic junction between the partition and ceiling has been analysed.

  14. Rib fractures and death from deletion of osteoblast βcatenin in adult mice is rescued by corticosteroids.

    PubMed

    Duan, JinZhu; Lee, Yueh; Jania, Corey; Gong, Jucheng; Rojas, Mauricio; Burk, Laurel; Willis, Monte; Homeister, Jonathon; Tilley, Stephen; Rubin, Janet; Deb, Arjun

    2013-01-01

    Ribs are primarily made of cortical bone and are necessary for chest expansion and ventilation. Rib fractures represent the most common type of non-traumatic fractures in the elderly yet few studies have focused on the biology of rib fragility. Here, we show that deletion of βcatenin in Col1a2 expressing osteoblasts of adult mice leads to aggressive osteoclastogenesis with increased serum levels of the osteoclastogenic cytokine RANKL, extensive rib resorption, multiple spontaneous rib fractures and chest wall deformities. Within days of osteoblast specific βcatenin deletion, animals die from respiratory failure with a vanishing rib cage that is unable to sustain ventilation. Increased bone resorption is also observed in the vertebrae and femur. Treatment with the bisphosphonate pamidronate delayed but did not prevent death or associated rib fractures. In contrast, administration of the glucocorticoid dexamethasone decreased serum RANKL and slowed osteoclastogenesis. Dexamethasone preserved rib structure, prevented respiratory compromise and strikingly increased survival. Our findings provide a novel model of accelerated osteoclastogenesis, where deletion of osteoblast βcatenin in adults leads to rapid development of destructive rib fractures. We demonstrate the role of βcatenin dependent mechanisms in rib fractures and suggest that glucocorticoids, by suppressing RANKL, may have a role in treating bone loss due to aggressive osteoclastogenesis.

  15. Rib Fractures and Death from Deletion of Osteoblast βcatenin in Adult Mice Is Rescued by Corticosteroids

    PubMed Central

    Duan, JinZhu; Lee, Yueh; Jania, Corey; Gong, Jucheng; Rojas, Mauricio; Burk, Laurel; Willis, Monte; Homeister, Jonathon; Tilley, Stephen; Rubin, Janet; Deb, Arjun

    2013-01-01

    Ribs are primarily made of cortical bone and are necessary for chest expansion and ventilation. Rib fractures represent the most common type of non-traumatic fractures in the elderly yet few studies have focused on the biology of rib fragility. Here, we show that deletion of βcatenin in Col1a2 expressing osteoblasts of adult mice leads to aggressive osteoclastogenesis with increased serum levels of the osteoclastogenic cytokine RANKL, extensive rib resorption, multiple spontaneous rib fractures and chest wall deformities. Within days of osteoblast specific βcatenin deletion, animals die from respiratory failure with a vanishing rib cage that is unable to sustain ventilation. Increased bone resorption is also observed in the vertebrae and femur. Treatment with the bisphosphonate pamidronate delayed but did not prevent death or associated rib fractures. In contrast, administration of the glucocorticoid dexamethasone decreased serum RANKL and slowed osteoclastogenesis. Dexamethasone preserved rib structure, prevented respiratory compromise and strikingly increased survival. Our findings provide a novel model of accelerated osteoclastogenesis, where deletion of osteoblast βcatenin in adults leads to rapid development of destructive rib fractures. We demonstrate the role of βcatenin dependent mechanisms in rib fractures and suggest that glucocorticoids, by suppressing RANKL, may have a role in treating bone loss due to aggressive osteoclastogenesis. PMID:23393600

  16. Decision Making in the Management of Extracapsular Fractures of the Proximal Femur - is the Dynamic Hip Screw the Prevailing Gold Standard?

    PubMed

    Jacob, Joshua; Desai, Ankit; Trompeter, Alex

    2017-01-01

    Currently, approximately half of all hip fractures are extracapsular, with an incidence as high as 50 in 100,000 in some countries. The common classification systems fail to explain the logistics of fracture classification and whether they all behave in the same manner. The Muller AO classification system is a useful platform to delineate stable and unstable fractures. The Dynamic hip screw (DHS) however, has remained the 'gold standard' implant of choice for application in all extracapsular fractures. The DHS relies on the integrity and strength of the lateral femoral wall as well as the postero-medial fragment. An analysis of several studies indicates significant improvements in design and techniques to ensure a better outcome with intramedullary nails. This article reviews the historical trends that helped to evolve the DHS implant as well as discussing if the surgeon should remain content with this implant. We suggest that the gold standard surgical management of extracapsular fractures can, and should, evolve.

  17. Traumatic superior orbital fissure syndrome: assessment of cranial nerve recovery in 33 cases.

    PubMed

    Chen, Chien-Tzung; Wang, Theresa Y; Tsay, Pei-Kwei; Huang, Faye; Lai, Jui-Pin; Chen, Yu-Ray

    2010-07-01

    Superior orbital fissure syndrome is a rare complication that occurs in association with craniofacial trauma. The characteristics of superior orbital fissure syndrome are attributable to a constellation of cranial nerve III, IV, and VI palsies. This is the largest series describing traumatic superior orbital fissure syndrome that assesses the recovery of individual cranial nerve function after treatment. In a review from 1988 to 2002, 33 patients with superior orbital fissure syndrome were identified from 11,284 patients (0.3 percent) with skull and facial fractures. Severity of cranial nerve injury and functional recovery were evaluated by extraocular muscle movement. Patients were evaluated on average 6 days after initial injury, and average follow-up was 11.8 months. There were 23 male patients. The average age was 31 years. The major mechanism of injury was motorcycle accident (67 percent). Twenty-two received conservative treatment, five were treated with steroids, and six patients underwent surgical decompression of the superior orbital fissure. After initial injury, cranial nerve VI suffered the most damage, whereas cranial nerve IV sustained the least. In the first 3 months, recovery was greatest in cranial nerve VI. At 9 months, function was lowest in cranial nerve VI and highest in cranial nerve IV. Eight patients (24 percent) had complete recovery of all cranial nerves. Functional recovery of all cranial nerves reached a plateau at 6 months after trauma. Cranial nerve IV suffered the least injury, whereas cranial nerve VI experienced the most neurologic deficits. Cranial nerve palsies improved to their final recovery endpoints by 6 months. Surgical decompression is considered when there is evidence of bony compression of the superior orbital fissure.

  18. Seismic behavior of outrigger truss-wall shear connections using multiple steel angles

    NASA Astrophysics Data System (ADS)

    Li, Xian; Wang, Wei; Lü, Henglin; Zhang, Guangchang

    2016-06-01

    An experimental investigation on the seismic behavior of a type of outrigger truss-reinforced concrete wall shear connection using multiple steel angles is presented. Six large-scale shear connection models, which involved a portion of reinforced concrete wall and a shear tab welded onto a steel endplate with three steel angles, were constructed and tested under combined actions of cyclic axial load and eccentric shear. The effects of embedment lengths of steel angles, wall boundary elements, types of anchor plates, and thicknesses of endplates were investigated. The test results indicate that properly detailed connections exhibit desirable seismic behavior and fail due to the ductile fracture of steel angles. Wall boundary elements provide beneficial confinement to the concrete surrounding steel angles and thus increase the strength and stiffness of connections. Connections using whole anchor plates are prone to suffer concrete pry-out failure while connections with thin endplates have a relatively low strength and fail due to large inelastic deformations of the endplates. The current design equations proposed by Chinese Standard 04G362 and Code GB50011 significantly underestimate the capacities of the connection models. A revised design method to account for the influence of previously mentioned test parameters was developed.

  19. Laboratory hydraulic fracturing experiments in intact and pre-fractured rock

    USGS Publications Warehouse

    Zoback, M.D.; Rummel, F.; Jung, R.; Raleigh, C.B.

    1977-01-01

    Laboratory hydraulic fracturing experiments were conducted to investigate two factors which could influence the use of the hydrofrac technique for in-situ stress determinations; the possible dependence of the breakdown pressure upon the rate of borehole pressurization, and the influence of pre-existing cracks on the orientation of generated fractures. The experiments have shown that while the rate of borehole pressurization has a marked effect on breakdown pressures, the pressure at which hydraulic fractures initiate (and thus tensile strength) is independent of the rate of borehole pressurization when the effect of fluid penetration is negligible. Thus, the experiments indicate that use of breakdown pressures rather than fracture initiation pressures may lead to an erroneous estimate of tectonic stresses. A conceptual model is proposed to explain anomalously high breakdown pressures observed when fracturing with high viscosity fluids. In this model, initial fracture propagation is presumed to be stable due to large differences between the borehole pressure and that within the fracture. In samples which contained pre-existing fractures which were 'leaky' to water, we found it possible to generate hydraulic fractures oriented parallel to the direction of maximum compression if high viscosity drilling mud was used as the fracturing fluid. ?? 1977.

  20. Piezosurgery for orbital decompression surgery in thyroid associated orbitopathy.

    PubMed

    Ponto, Katharina A; Zwiener, Isabella; Al-Nawas, Bilal; Kahaly, George J; Otto, Anna F; Karbach, Julia; Pfeiffer, Norbert; Pitz, Susanne

    2014-12-01

    The purpose of this study was to assess a piezosurgical device as a novel tool for bony orbital decompression surgery. At a multidisciplinary orbital center, 62 surgeries were performed in 40 patients with thyroid associated orbitopathy (TAO). Within this retrospective case-series, we analyzed the medical records of these consecutive unselected patients. The reduction of proptosis was the main outcome measure. Indications for a two (n = 27, 44%) or three wall (35, 56%) decompression surgery were proptosis (n = 50 orbits, 81%) and optic neuropathy (n = 12, 19%). Piezosurgery enabled precise bone cuts without intraoperative complications. Proptosis decreased from 23.6 ± 2.8 mm (SD) by 3 mm (95% CI: -3.6 to -2.5 mm) after surgery and stayed stable at 3 months (-3 mm, 95% CI: -3.61 to -2.5 mm, p < 0.001, respectively). The effect was higher in those with preoperatively higher values (>24 mm versus ≤ 24 mm: -3.4 mm versus -2.81 mm before discharge from hospital and -4.1 mm versus -2.1 mm at 3 months: p < 0.001, respectively). After a mean long-term follow-up period of 14.6 ± 10.4 months proptosis decreased by further -0.7 ± 2.0 mm (p < 0.001). Signs of optic nerve compression improved after surgery. Infraorbital hypesthesia was present in 11 of 21 (52%) orbits 3 months after surgery. The piezosurgical device is a useful tool for orbital decompression surgery in TAO. By cutting bone selectively, it is precise and reduces the invasiveness of surgery. Nevertheless, no improvement in outcome or reduction in morbidity over conventional techniques has been shown so far. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.