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Sample records for burr hole drainage

  1. Percutaneous epidural drainage through a burr hole

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    Priscila M Falsarella

    2016-01-01

    Full Text Available Intracranial extradural collection may cause an increase in intracranial pressure, requiring rapid emergency treatment to reduce morbidity and mortality. We described an alternative CT-guided percutaneous access for extradural collection drainage. We report a case of a patient with previous craniectomy for meningioma ressection who presented to the Emergency Department with symptoms of intracranial hypertension. Brains CT showed a extradural collection with subfalcine herniation. After multidisciplinary discussion a CT-guided percutaneous drainage through previous burr hole was performed. The patient was discharged after 36 hours of admission, without further symptoms. We describe a safe and effective alternative percutaneous access for extradural collection drainage in patients with previous burr hole.

  2. Comparing twist-drill drainage with burr hole drainage for chronic subdural hematoma

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    LIN Xin

    2011-06-01

    Full Text Available 【Abstract】Objective: The surgical management of chronic subdural hematoma (CSDH is still a controver- sial issue, and a standard therapy has not been established because of the unclear pathogenic mechanisms in CSDH. The intention of this paper is to find a simple and efficient surgical procedure for CSDH. Methods: A retrospective study of 448 patients with CSDH by surgical treatment during 2005 to 2009 was con- ducted in order to compare the efficiency between two dif- ferent primary surgical methods, i.e. twist-drill drainage with- out irrigation in Group A (n=178 and one burr-hole with irrigation in Group B (n=270. The results were statistically analyzed. Results: The reoperation rates in Group A and Group B were 7.9% and 11.9% respectively. The good outcome rate was 88.8% and 75.5%, the complication was 7.9% and 20.7% in Group A and Group B, respectively. Conclusions: The burr-hole drainage with irrigation of the hematoma cavity is not beneficial to the outcome and prognosis. Irrigation is not important in the surgical treat- ment for CSDH. Thus in initial treatment, twist-drill drainage without irrigation of the hematoma cavity is recommended because it is relatively safe, time-saving and cost-effective. Key words: Hematoma, subdural; Brain injury, chronic; Drainage

  3. "Rabbit Ear" scalp deformity caused by massive subdural effusion in infant following bilateral burr-hole drainage

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    Guru Dutta Satyarthee

    2013-01-01

    Full Text Available Subdural effusion (SDE in an infant is a rare clinical scenario, which may be secondary to a variety of etiologies. Massive SDE is an extremely rare complication of head injury. It usually runs a self-limiting course. Though neurosurgical intervention is occasionally needed, different methods of surgical procedure for management includes burr-hole alone, burr-holes with subdural drain placement, twist drill craniotomy with drain and even craniotomy. The authors report a rare case of progressive massive SDE, which despite bilateral burr-hole placement and drainage failed and presented with visual deterioration and massive bulge of scalp at burr-hole sites producing rabbit ear sign in a 10 month old infant. Ultimately cystoperitoneal shunt was carried out in a desperate attempt to prevent impending rupture of scalp sutures at sites of previous burr-hole placement. Astonishingly not only complete resolution of hygroma, but visual recovery also took place. Patient is doing well at 6 months following shunt with regaining normal vision and appropriate developmental milestones. A magnetic resonance imaging scan of brain at last follow-up revealed mild ventriculomegaly with subduro-peritoneal shunt in situ and rest of brain was unremarkable. Such cases have not been reported in literature until date.

  4. Burr-hole Irrigation with Closed-system Drainage for the Treatment of Chronic Subdural Hematoma: A Meta-analysis.

    Science.gov (United States)

    Xu, Chen; Chen, Shiwen; Yuan, Lutao; Jing, Yao

    2016-01-01

    There is controversy among neurosurgeons regarding whether irrigation or drainage is necessary for achieving a lower revision rate for the treatment of chronic subdural hematoma (CSDH) using burr-hole craniostomy (BHC). Therefore, we performed a meta-analysis of all available published reports. Multiple electronic health databases were searched to identify all studies published between 1989 and June 2012 that compared irrigation and drainage. Data were processed by using Review Manager 5.1.6. Effect sizes are expressed as pooled odds ratio (OR) estimates. Due to heterogeneity between studies, we used the random effect of the inverse variance weighted method to perform the meta-analysis. Thirteen published reports were selected for this meta-analysis. The comprehensive results indicated that there were no statistically significant differences in mortality or complication rates between drainage and no drainage (P > 0.05). Additionally, there were no differences in recurrence between irrigation and no irrigation (P > 0.05). However, the difference between drainage and no drainage in recurrence rate reached statistical significance (P meta-analysis suggest that burr-hole surgery with closed-system drainage can reduce the recurrence of CSDH; however, irrigation is not necessary for every patient.

  5. Contralateral acute epidural haematoma following evacuation of a chronic subdural haematoma with burr-hole craniostomy and continuous closed system drainage: a rare complication.

    Science.gov (United States)

    Panourias, Ioannis G; Skandalakis, Panajiotis N

    2006-06-01

    Chronic subdural haematoma (CSDH) is one of the most frequent causes for neurosurgical intervention. Although the prognosis is generally good and treatment modalities are well established, some devastating intracranial haematomas can complicate its evacuation. The authors report here a case of an acute epidural haematoma occurring after evacuation of a contralateral chronic subdural haematoma (CSDH) with burr-hole craniostomy and continuous closed system drainage without irrigation. Since this is a rare, but potentially life-threatening, complication, clinicians should suspect its occurrence when an unexpected postoperative course is demonstrated.

  6. 慢性硬膜下血肿钻孔引流术后再出血的原因及治疗%Mechanism and treatment of intracapsular bleeding after burr hole subdural drainage for chronic subdural hematoma

    Institute of Scientific and Technical Information of China (English)

    王良伟; 李监松; 徐光斌; 吴永; 潘晶晶; 王俊芳

    2015-01-01

    目的:探讨慢性硬膜下血肿钻孔引流术后再出血的原因及治疗原则。方法回顾性分析2011年7月~2013年6月收治的80例慢性硬膜下血肿钻孔引流术治疗患者的临床资料,其中4例患者出现包膜内出血形成血肿,患者均手术治疗并对血肿外包膜做病理检查。结果3例手术治疗后痊愈,1例因术后并发症死亡。包膜病理检查示,大量新生毛细血管扩张充血,有炎性细胞、胶原纤维和纤维细胞等,包膜内的毛细血管壁不完整。结论慢性硬膜下血肿外膜新生血管结构异常是慢性硬膜下血肿术后包膜内出血的原因之一,包膜内出血一经确诊应首选手术治疗。%Objective To explore mechanism and management of intracapsular bleeding after burr hole subdural drainage for chronic subdural hematoma ( CSDH) .Method The clinical data of 80 patients with CSDH treated with burr hole subdural drainage from July , 2011 to June,2013,were analyzed retrospectively .4 cases were treated with craniotomy because of hematoma in capsule after burr hole subdural drainage , light microscopy was used to observe the ultrastructure of the outer membrane of them .Results 3 patients were cured after craniotomy ,1 died because of complication .Light microscopy showed dilated and congested marcocapillaries with a wide vascular lumen in the outer membrane of the hematoma capsule , including inflammatory cells , collagenous fiber , fibrocyte and so on , endothelial cell in the marcocapillaries was discontinous or partically dissolved .Conclusions Variation of structure of these fragile new vessels may play an important role in bleeding of capsule after burr hole subdural drainage in treatment of CSDH.Craniotomy should be the first line treatment .

  7. Comparative study between cortical bone graft versus bone dust for reconstruction of cranial burr holes

    OpenAIRE

    Worm, Paulo Valdeci; Ferreira,Nelson Pires; Faria, Mário de Barros; Ferreira, Marcelo Paglioli; Kraemer,Jorge Luiz; Collares, Marcus Vinicius Martins

    2010-01-01

    Background: As a consequence of the progressive evolution of neurosurgical techniques, there has been increasing concern with the esthetic aspects of burr holes. Therefore, the objective of this study was to compare the use of cortical bone graft and bone dust for correcting cranial deformities caused by neurosurgical trephines. Methods: Twenty-three patients were enrolled for cranial burr hole reconstruction with a 1-year follow-up. A total of 108 burr holes were treated; 36 burr holes were ...

  8. Hole quality and burr reduction in drilling aluminium sheets

    DEFF Research Database (Denmark)

    Pilny, Lukas; De Chiffre, Leonardo; Piska, Miroslav;

    2011-01-01

    Optimization of the metal drilling process requires creation of minimum amount of burrs and uniform appearance of the drilled holes. In this paper, an experimental investigation was performed on 2 mm sheets of wrought aluminium alloy Al99.7Mg0.5Cu-H24, using 1.6 and 2 mm diameter drills. Cutting...... data, clamping conditions, and drill geometry were varied in order to optimize the process and reach the desired quality. The results revealed possible reduction of burr occurrence on both the entry and exit side of the sheet, requiring no additional deburring. The demand on the uniform appearance...... of drilled holes was fulfilled as well as high productivity achieved. Such optimized process results in a noticeable production cost reduction....

  9. Hole quality and burr reduction in drilling aluminium sheets

    DEFF Research Database (Denmark)

    Pilny, Lukas; De Chiffre, Leonardo; Piska, Miroslav;

    2012-01-01

    Optimization of the metal drilling process requires creation of minimum amount of burrs and uniform appearance of the drilled holes. In this paper, an experimental investigation was performed on 2 mm sheets of wrought aluminium alloy Al99.7Mg0.5Cu-H24, using 1.6 and 2 mm diameter drills. Cutting...... data, clamping conditions, and drill geometry were varied in order to optimize the process and reach the desired quality. The results revealed possible reduction of burr occurrence on both the entry and exit side of the sheet, requiring no additional deburring. The demand on the uniform appearance...... of drilled holes was fulfilled as well as high productivity achieved. Such optimized process results in a noticeable production cost reduction....

  10. The Effectiveness of the Stereotactic Burr Hole Technique for Deep Brain Stimulation.

    Science.gov (United States)

    Toyoda, Keisuke; Urasaki, Eiichirou; Umeno, Tetsuya; Sakai, Waka; Nagaishi, Akiko; Nakane, Shunya; Fukudome, Takayasu; Yamakawa, Yuzo

    2015-01-01

    Deep brain stimulation (DBS) is performed by burr hole surgery. In microelectrode recording by multi-channel parallel probe, because all microelectrodes do not always fit in the burr hole, additional drilling to enlarge the hole is occasionally required, which is time consuming and more invasive. We report a stereotactic burr hole technique to avoid additional drilling, and the efficacy of this novel technique compared with the conventional procedure. Ten patients (20 burr holes) that received DBS were retrospectively analyzed (5 in the conventional burr hole group and 5 in the stereotactic burr hole group). In the stereotactic burr hole technique, the combination of the instrument stop slide of a Leksell frame and the Midas Rex perforator with a 14-mm perforator bit was attached to the instrument carrier slide of the arc in order to trephine under stereoguidance. The efficacy of this technique was assessed by the number of additional drillings. Factors associated with additional drilling were investigated including the angle and skull thickness around the entry points. Four of the 10 burr holes required additional drilling in the conventional burr hole group, whereas no additional drilling was required in the stereotactic burr hole group (p = 0.043). The thicknesses in the additional drilling group were 10.9 ± 0.9 mm compared to 9.1 ± 1.2 mm (p = 0.029) in the non-additional drilling group. There were no differences in the angles between the two groups. The stereotactic burr hole technique contributes to safe and exact DBS, particularly in patients with thick skulls.

  11. Multiple burr hole surgery as a treatment modality for pediatric moyamoya disease

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    Ravindranath Kapu

    2010-01-01

    Full Text Available Objective : To re-emphasize that indirect revascularization surgery alone, where multiple burr holes and arachnoid openings are made over both cerebral hemispheres, is beneficial in the treatment of moyamoya disease (MMD in children. Clinical Presentation : We report a 10-year-old boy who presented with complaints of episodic headache for the last 5 years. At the peak of his headache he had visual disturbances and acute onset weakness of left-sided limbs, recovering within a few minutes. He had no focal neurological deficits. Radiological investigations revealed abnormal findings, demonstrating the features of MMD. Surgical Management : He underwent bilateral multiple burr holes, dural and arachnoid opening over the frontal, parietal and temporal regions of each hemisphere. The elevated periosteal flap was placed in contact with the exposed brain through each burr hole. Results : On 6-months follow-up he had only one episode of transient ischemic attack. Postoperative four vessel angiogram demonstrated excellent cerebral revascularization around the burr hole sites, and single photon emission computerized tomography imaging showed hypoperfusion in the right temporo-occipital area suggestive of an old infarct with no other perfusion defect in the rest of the brain parenchyma. Conclusion : In children with MMD this relatively simple surgical technique is effective and safe, and can be used as the only treatment without supplementary revascularization procedures. This procedure can be done in a single stage on both sides and the number of burr holes made over each hemisphere depends on the extent of the disease.

  12. Evaluation of trans burr hole ultrasonography usefulness in a resource-limited setting

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    V de P. Djientcheu

    2013-01-01

    Full Text Available Purpose: Transcranial ultrasound (US imaging of intracranial structures is a reliable technique that requires an opening in the skull. In young children the fontanelle serves this purpose, but in adults a postoperative skull defect or some other acquired skull bone defect could be used as potential windows for transcranial US imaging. This study is an audit on the usefulness of the trans burr hole US intracranial imaging technique in a neurosurgical unit in Cameroon (sub-Saharan Africa. Materials and Methods: From January 2001 through December 2004, all files of patients consecutively operated in the neurosurgical unit of the Central Hospital of Yaounde, who underwent an US exploration in the postoperative period through the acquired bone defect or through a skull fracture were reviewed. Transcranial US results were validated by a complementary CT scan or postoperative findings. Results: Seventeen patients were included. Trans burr hole US was effective in diagnosing or in excluding postoperative complications. Hydrocephalus was diagnosed (two cases or excluded (five cases after posterior a fossa surgery (five cases or in case of suspicion of drain dysfunction (two cases. Abscess (one case or chronic subdural hematoma (two cases were detected or excluded after cranial surgery for tumours (three cases, aneurysm (one case, compound depressed skull fracture (one case, or intracranial hematoma (three cases. In one case of posttraumatic swelling of the scalp, the US technique revealed an acquired meningoencephalocele. In one case, residual subdural empyema was detected through trans burr hole US. Conclusion: Trans burr hole US technique may be considered in the diagnosis of postoperative complications (abscesses or hematoma in adults after intracranial surgery or ventriculoperitoneal drain dysfunction especially in resource-limited setting as it is both cheap and widely available.

  13. Burr-hole craniotomy treating chronic subdural hematoma:a report of 398 cases

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan; XIA Jun-zhe; WU An-hua; WANG Yun-jie

    2010-01-01

    Objective: To investigate the treatment of chronic subdural hematoma (CSDH) with burr-hole craniotomy in our hospital.Methods: From January 2004 to December 2009, 398patients with CSDH, 338 males and 60 females (male/female=5.63/1 ), received burr-hole craniotomy in our hospital.The median age was 60 years with the mean age of (58. 1± 18. 1 )years, (65.0±14.5) years for females and (57.0±18.2) years for males. Trauma history was determined in 275 patients (69. 1%).Burr-hole craniotomy was performed under local anesthesia in 368 patients and general anesthesia in 30 patients.CSDH was classified into 3 groups according to the density on CT scan. Clinical data concerning etiologies, symptoms and signs, concomitant diseases, diagnosis, therapies and outcomes were investigated retrospectively. Patients' neurological status on admission and at discharge was also classified to judge the outcomes.Results: Generally, trauma history showed few differences between those over 60 years old and under 60 years old, but showed obvious differences when gender was taken into account. Totally 123 male patients (60.0% of 204 cases) suffering from head injuries were under 60 years,whereas 35 female patients (85.4% of 41 cases) with trauma histories were over 60 years. The duration from trauma to appearance of clinical symptoms was (84.0±61.7) days (range,0-1493 days). Traumatic accident was the leading etiology,other accompanying diseases such as cerebral vascular disease, hypertension, etc, were also predisposing factors.Commonly, the elderly presented with hemiplegia/hemidysesthesia/hemiataxia and the young with headache.Most CSDH patients (95.6%) treated with burr-hole craniotomy successfully recovered. However, postoperative complications occurred in 17 cases, including recurrence of CSDH in 15 cases, subdural abscess in 1 case and pneumonia in 3 cases.Conclusion: Burr-hole craniotomy is an easy, efficient and reliable way to treat CSDH.

  14. Quantitative computed tomography and cranial burr holes: a model to evaluate the quality of cranial reconstruction in humans.

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    Worm, Paulo Valdeci; Ferreira, Nelson Pires; Ferreira, Marcelo Paglioli; Kraemer, Jorge Luiz; Lenhardt, Rene; Alves, Ronnie Peterson Marcondes; Wunderlich, Ricardo Castilho; Collares, Marcus Vinicius Martins

    2012-05-01

    Current methods to evaluate the biologic development of bone grafts in human beings do not quantify results accurately. Cranial burr holes are standardized critical bone defects, and the differences between bone powder and bone grafts have been determined in numerous experimental studies. This study evaluated quantitative computed tomography (QCT) as a method to objectively measure cranial bone density after cranial reconstruction with autografts. In each of 8 patients, 2 of 4 surgical burr holes were reconstructed with autogenous wet bone powder collected during skull trephination, and the other 2 holes, with a circular cortical bone fragment removed from the inner table of the cranial bone flap. After 12 months, the reconstructed areas and a sample of normal bone were studied using three-dimensional QCT; bone density was measured in Hounsfield units (HU). Mean (SD) bone density was 1535.89 (141) HU for normal bone (P holes is an excellent model to accurately measure the quality of new bone in cranial reconstructions and also seems to be an appropriate choice of experimental model to clinically test any cranial bone or bone substitute reconstruction.

  15. Burr Utility

    NARCIS (Netherlands)

    Ikefuji, M.; Laeven, R.J.A.; Magnus, J.R.; Muris, C.H.M.

    2010-01-01

    This note proposes the Burr utility function. Burr utility is a flexible two-parameter family that behaves approximately power-like (CRRA) remote from the origin, while exhibiting exponential-like (CARA) features near the origin. It thus avoids the extreme behavior of the power family near the origi

  16. Analysis of risk factors for chronic subdural haematoma recurrence after burr hole surgery: optimal management of patients on antiplatelet therapy.

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    Okano, Atsushi; Oya, Soichi; Fujisawa, Naoaki; Tsuchiya, Tsukasa; Indo, Masahiro; Nakamura, Takumi; Chang, Han Soo; Matsui, Toru

    2014-04-01

    OBJECTIVE. Not much is known about surgical management of patients with chronic subdural haematoma (CSDH) treated with antiplatelet or anticoagulant therapy. The aims of this study were to review the surgical outcomes of patients with CSDH and assess the risks of antiplatelet in their surgical management. METHODS. We retrospectively analysed 448 consecutive patients with CSDH treated by one burr hole surgery at our institution. Among them, 58 patients had been on antiplatelet therapy. We discontinued the antiplatelet agents before surgery for all 58 patients. For 51 of these 58 patients (87.9%), early surgery was performed within 0-2 days from admission. We analysed the association between recurrence and patient characteristics, including history of antiplatelet or anticoagulant therapy; age (antiplatelet or anticoagulant therapy did not significantly increase recurrence risk. Also, the recurrence rate from early surgery (0-2 days from drug cessation) for patients on antiplatelet therapy was not significantly higher than that from elective surgery (5 days or more after drug cessation). However, multivariate analysis revealed that previous history of cerebral infarction was an independent risk factor for CSDH recurrence. CONCLUSIOns. Our overall data support the safety of early surgery for patients on the preoperative antiplatelet therapy without drug cessation or platelet infusion. Patients with a previous history of infarction may need to be closely followed regardless of antiplatelet or anticoagulant therapy.

  17. Long hole waterjet drilling for gas drainage

    Energy Technology Data Exchange (ETDEWEB)

    Matt Stockwell; M. Gledhill; S. Hildebrand; S. Adam; Tim Meyer [CMTE (Australia)

    2003-04-01

    In-seam drilling for gas drainage is now an essential part of operations at many Australian underground coalmines. The objective of this project is to develop and trial a new drilling method for the accurate and efficient installation of long inseam boreholes (>1000 metres). This involves the integration of pure water-jet drilling technology (i.e. not water-jet assisted rotary drilling) developed by CMTE with conventional directional drilling technology. The system was similar to conventional directional drilling methods, but instead of relying on a down-hole-motor (DHM) rotating a mechanical drill bit for cutting, high pressure water-jets were used. The testing of the system did not achieve the full objectives set down in the project plan. A borehole greater than 1000 metres was not achieved. The first trial site had coal that was weathered, oxidized and dry. These conditions significantly affected the ability of the drilling tool to stay 'in-seam'. Due to the poor conditions at the first trial, many experimental objectives were forwarded to the second field trial. In the second trial drilling difficulties were experienced, this was due to the interaction between the confinement of the borehole and the dimensions of the down hole drilling assembly. This ultimately reduced the productivity of the system and the distance that could be drilled within the specified trial periods. Testing in the first field trial did not show any indication that the system would have this difficulty.

  18. Role of CT perfusion imaging in evaluating the effects of multiple burr hole surgery on adult ischemic Moyamoya disease

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    Dai, Dong Wei; Zhao, Wen Yuan; Yang, Zhi Gang; Li, Qiang; Liu, Jian Min [Second Military Medical University, Department of Neurosurgery, Changhai Hospital, Shanghai (China); Zhang, Yong Wei [Second Military Medical University, Department of Neurology, Changhai Hospital, Shanghai (China); Xu, Bing; Ma, Xiao Long; Tian, Bing [Second Military Medical University, Department of Radiology, Changhai Hospital, Shanghai (China)

    2013-12-15

    To evaluate the effects of the multiple burr hole (MBH) revascularization on ischemic type adult Moyamoya disease (MMD) by computed tomography perfusion (CTP). Eighty-six ischemic MMD patients received CTP 1 week before and 3 weeks after MBH operation. Fifty-seven patients received it again at 6 month and underwent digital subtraction angiography (DSA) and mRS follow-up. Cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), time to peak (TTP), and relative values of ischemic symptomatic hemispheres were measured. Differences in pre- and post-surgery perfusion CT values were assessed. There were significant differences of CBF, TTP, and relative time to peak (rTTP) in ischemic hemisphere between 1 week before and 3 weeks after surgery, and no significant difference in relative cerebral blood flow (rCBF), CBV, relative cerebral blood volume (rCBV), MTT, relative mean transit time (rMTT). According to whether there was symptom improvement or not on 3 weeks after MBH, the rTTP value was not statistically significant in the patients whose symptoms were not improved at all on 3 weeks after operation. Six-month follow-up showed that CBF, rCBF, and rCBV values were significantly higher than those before operation. Postoperative MTT, TTP, rMTT, and rTTP values were significantly lower than those before operation. CTP is a sensitive method to obtain functional imaging of cerebral microcirculation, which can be a noninvasive assessment of the abnormalities of intracranial arteries and cerebral perfusion changes in MMD before and after surgery. CBF and TTP map, especially the relative values of TTP, seems to have the capability of being quite sensitive to the presence of altered brain perfusion at early time after indirect revascularization. (orig.)

  19. The Safety and Efficacy of Dexmedetomidine versus Sufentanil in Monitored Anesthesia Care during Burr-Hole Surgery for Chronic Subdural Hematoma: A Retrospective Clinical Trial

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    Wenming Wang

    2016-11-01

    Full Text Available Background: Chronic subdural hematoma (CSDH is a very common clinical emergency encountered in neurosurgery. While both general anesthesia (GA and monitored anesthesia care (MAC can be used during CSDH surgery, MAC is the preferred choice among surgeons. Further, while dexmedetomidine (DEX is reportedly a safe and effective agent for many diagnostic and therapeutic procedures, there have been no trials to evaluate the safety and efficacy of DEX vs. sufentanil in CSDH surgery. Objective: To evaluate the safety and efficacy of DEX vs. sufentanil in MAC during burr-hole surgery for CSDH.Methods: In all, 215 fifteen patients underwent burr-hole surgery for CSDH with MAC and were divided into three groups: Group D1 (n=67, DEX infusion at 0.5 μg·kg–1 for 10 min, Group D2 (n=75, DEX infusion at 1 μg·kg–1 for 10 min, and Group S (n=73, sufentanil infusion 0.3 μg·kg–1 for 10 min. Ramsay sedation scale (RSS of all three groups was maintained at 3. Anesthesia onset time, total number of intraoperative patient movements, hemodynamics, total cumulative dose of DEX, time to first dose and amount of rescue midazolam or fentanyl, percentage of patients converted to alternative sedative or anesthetic therapy, postoperative recovery time, adverse events, and patient and surgeon satisfaction scores were recorded.Results: The anesthesia onset time was significantly less in group D2 (17.36±4.23 vs. 13.42±2.12 vs. 15.98±4.58 min, respectively, for D1, D2, S; P<0.001. More patients in groups D1 and S required rescue midazolam to achieve RSS=3 (74.63% vs. 42.67% vs. 71.23%, respectively, for D1, D2, S; P<0.001. However, the total dose of rescue midazolam was significantly higher in group D1 (2.8±0.3 vs. 1.9±0.3 vs. 2.0±0.4 mg, respectively, for D1, D2, S; P<0.001. The time to first dose of rescue midazolam was significantly longer in group D2 (17.32±4.47 vs. 23.56±5.36 vs. 16.55±4.91 min, respectively, for D1, D2, S; P<0.001. Significantly fewer

  20. 颅骨多处钻孔硬膜翻转并骨膜贴敷术治疗烟雾病%Therapeutic effect of multiple burr - hole operation combined with dural inversion and periosteal synangiosis for moyamoya disease

    Institute of Scientific and Technical Information of China (English)

    赵旭; 王志刚; 李卫国; 曲春城; 孟庆虎; 王成伟

    2012-01-01

    目的 初步探讨应用颅骨多处钻孔硬膜翻转并骨膜贴敷术治疗烟雾病的疗效.方法 对25例烟雾病患者行颅骨多处钻孔硬膜翻转并骨膜贴敷术,术后随访3个月-3年.结果 20例缺血型患者术前原有症状术后均好转,5例出血型患者术后未发生再出血.9例患者行DSA复查,造影结果显示38个骨孔均有新生血管生长,缺血区血运改善.手术并发症包括硬膜下血肿1例、暂时性神经功能障碍5例、发热1例.结论 单独应用颅骨多处钻孔硬膜翻转并骨膜贴敷术治疗烟雾病是简单、安全、有效的.%Objective To explore the therapeutic effect of multiple burr - hole operation combined with dural inversion and periosteal synangiosis for moyamoya disease.Methods The multiple burr - hole operation combined with dural inversion and periosteal synangiosis was performed on 25 patients with moyamoya disease,which were followed up for three months to three years.Results The clinical symptoms of the 20 patients with ischemic moyamoya disease gradually improved after the operations.There was no postoperative rebleeding in the 5 patients with hemorrhagic moyamoya disease.Nine patients were reexamined by digital subtraction angiogram (DSA).The postoperative DSA results revealed there was apparent neovascularization in all the 38 burr - holes and the revascularization of the ischemic cerebral tissue was obtained. The postoperative complications.included one case of subdural hematoma,5 cases of postoperative temporary neurological deficits and 1 case of fever.Conclusion Multiple burr- hole operation combined with dural inversion and periosteal synangiosis is a simple,safe and effective treatment method for movamova disease as a sole treatment without supplementary revascularization procedures.

  1. COMPOSITE ELEMENT METHOD FOR SEEPAGE ANALYSIS OF GEOTECHNICAL STRUCTURES WITH DRAINAGE HOLE ARRAY

    Institute of Scientific and Technical Information of China (English)

    CHEN Sheng-hong; XU Qing; HU Jing

    2004-01-01

    Air element concept and Composite Element Method (CEM) were introduced in this paper firstly, and then an explicit drainage holes element model was developed. The main advantage of the new model is that it allows drainage holes to be located within soil elements. Therefore the mesh generation of complicated geotechnical structures with a large number of seepage drainage holes becomes relatively convenient and feasible. This will further facilitate the optimal design of seepage control system, and in this case the calculation mesh can be kept unchanged when the number, position and orientation of drainage holes are adjusted. The model was been implemented in software. A sluice foundation seepage control problem was studied, by which the validity and the robustness of the new model were verified.

  2. "Plug" ósseo autógeno para orifícios de trepanação: nota técnica Autogenic bone plug to seal burr holes: technical note

    Directory of Open Access Journals (Sweden)

    JOSUÉ GUIMARÃES GRANHA VIALOGO

    1999-12-01

    Full Text Available Vários materiais são utilizados para ocluir os orifícios de trepanação em neurocirurgia, por motivos variados: para evitar fístula liquórica após trepanações, para auxiliar a fixação do "flap" ósseo e por motivos estéticos, na região frontal. Dentre estes materiais citamos os heterólogos (botões de silicone, miniplacas de metal, cera de osso, metilmetacrilato, gelfoam, cimento de polímero vegetal, cerâmica de hidroxiapatita, e os autólogos (pó de osso originado da trepanação, gordura, músculo, aponeurose. Os materiais heterólogos ou sintéticos podem provocar reação de corpo estranho com erosão da pele e exposição do material, tornando necessária sua retirada, em tempo variável no pós-operatório. Há cerca de três anos, o autor vem utilizando um botão ou "plug" ósseo autólogo, feito com surgicel e o pó de osso proveniente da trepanação, com bom resultado estético eliminando as desconfortáveis depressões cranianas pós-trepanação. Apresentamos a técnica de confecção deste prático `plug ósseo autólogo'. Nas neuroendoscopias, praticamente sanou-se o problema da fístula liquórica e reação de corpo estranho. Encorajamos a utilização deste botão ósseo autólogo em nosso meio, como método eficiente, econômico e biologicamente aceitável para ocluir orifícios cranianos de trepanação.Many neurosurgical procedures can be performed by a single burr hole: neuroendoscopy, microvascular decompression, stereotactic procedures, chronic subdural haematomas. It is technically difficult to suture and close the dura, located at the bottom of such holes, which can lately lead to CSF leakage. On the other hand, the surgical material used to seal the burr holes can be divided in heterogenic (metal screws, silicon plugs, gelfoam, bone wax, metilmetacrilate, hidroxiapatite, and autogenic (fat, aponeurosis, muscle, and bone dust from trephination. The heterogenic group always brings the possibility of

  3. The enlarged burr-hole craniotomy for treatment of hypertensive intracerebral hemorrhage in geriatric patients%小骨窗开颅手术治疗老年性高血压脑出血51例临床分析

    Institute of Scientific and Technical Information of China (English)

    徐已奕; 钟春龙; 郑彦; 张明坤; 崔振文; 吴增宝; 王勇; 江基尧; 罗其中

    2011-01-01

    目的 研究老年性高血压脑出血的微创治疗策略.方法 回顾性分析51例应用小骨窗开颅技术治疗的老年(>65岁)高血压脑出血患者.均在直视下清除血肿,术后血肿残余大于15 ml者辅助尿激酶稀释液灌注引流.结果 血肿近全清除36例,大部清除14例,再出血后二次手术清除1例.由于老年病人存在脑萎缩,血肿清除后减压均较充分.随访6个月至2年,GOS优28例,中残15例.重残7例,死亡1例.恢复良好率达84.3%.结论 小骨窗开颅手术治疗高血压脑出血,具有微创、可视、省时、病人恢复快等优点.%Objective To investigate the strategy of minimally invasive treatment for hypertensive intracerebral hemorrhage in geriatric patients. Methods Review the clinical date of fifty- one aged patients(>65years old) who were treated with the enlarged burr-hole craniotomy because of hypertensive intracerebral hemorrhage. All hematomas were evacuated under direct visualization. If the volume of residual hematoma on follow-up CT was more than 15ml, a drainage procedure would be performed after the perfusion of the urokinase. Results Nearly total e-vacuation of hematoma was achieved in 36 cases , subtotal evacuation in 14 cases, but in 1 case rebleeding occurred and reoperation was done. The decompression was sufficient because of the shrinkage of brain tissues in aged patients. Followed up for 6 months to 2 years, good recovery was found in 28 cases, moderate disability in 15 cases, severe disability in 7 cases and death in 1 case according to the glasgow outcome scale ( GOS) . The rate of favorable outcomes was 84. 3%. Conclusion The advantages of enlarged burr-hole craniotomy in the treatment of hypertensive intracerebral hemorrhage are minimally invasive, visible, less time consuming and quick recovery of patients.

  4. Research on the Reasonable Spacing of Holes in Gas Drainage along Coal Seams in Consideration of the Superimposed Effect of Drainage

    Directory of Open Access Journals (Sweden)

    Li Bo

    2016-02-01

    Full Text Available o determine the reasonable spacing of holes for gas drainage, an experimental study was conducted on the effective influence radius of drilling hole through the pressure drop method based on the actual condition of coal seams. The coal seam that contains gas is regarded as elastic-plastic dual media. The governing equation of gas transport is established by analyzing the different flow forms of gas in the pore and fissure systems as well as by considering the mass exchange capacity in the pore-fissure system. The equation is embedded into COMSOL Multiphysics (COMSOL software to simulate the gas drainage effect further by drilling along a coal seam under a 3-D space. Upon confirming the effective radius and drainage influence radius of a single pore, the holes for gas drainage can be reasonably spaced along the coal seam by analyzing the change features of coal permeability around the borehole and the functional mechanism of the superimposed effect of drainage, namely, 2r≤L≤R. The study results can reliably guide practical gas drainage theoretically and can also effectively lower the cost of gas drainage as well as ensure the safe production in mines.

  5. Influence of different types of sharpening in straight flute drills on burr formation

    Directory of Open Access Journals (Sweden)

    Rodrigo Barros de Borba

    2016-08-01

    Full Text Available Drilling is among the most important manufacturing processes in modern industry. Information on the dynamics of the drilling process is very important to define optimum input parameters. The minimization of burrs is a great challenge in drilling process. Current analysis was carried out with stepped solid carbide drills with straight flutes in drilling of the aluminum alloy A306. Burr height was measured at hole exits and evaluated with ANOVA technique. Results showed that the feed rate and cutting speed variation exhibited significant influence while sharpening was the most important parameter on burr formation.

  6. A METHOD OF PROVIDING BURR-FREE BORES

    DEFF Research Database (Denmark)

    2004-01-01

    By thermal-based removal of material, for instance by way of laser drilling or laser ablation, the material is removed from the article (2) in form of steam or drops. The material is removed by being subjected to a short-term intense laser pulse (4) causing a generation of considerable pressure...... from vaporised and/or ionised material. As a result, vaporised melt material is sprayed to the sides or upwards along the sides of a drilled hole. These squirts can either damage the surface around the processed area or result in an upward burr. The method according to the invention provides...... an additional local steam/plasma pressure causing the ejected material to change direction in such a manner that the surface of the material is not damaged or a stricking burr is not formed. The local steam/plasma pressure can, for instance, be provided by an intense secondary laser beam being emitted downwards...

  7. Progress in the battle with the burr

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, L.K.

    1981-04-01

    Although US industry still spends more for removing burrs than it needs to, significant improvements in deburring are developing. Standards for burrs are now in reasonably common use at many companies. The mechanisms by which burrs form and by which one can predict their properties have been documented, and some deburring economics have been described. Advances in a number of processes have emerged within the past two years, and the entire subject of deburring has been receiving greater emphasis in most high-technology countries than before.

  8. Three-dimensional numerical simulation of methane drainage by high-level drill holes in a lower protective coal seam with a‘‘U’’ type face

    Institute of Scientific and Technical Information of China (English)

    Xingkui Liu; Shuzhao Yang

    2014-01-01

    Different drill-hole positions may produce different drainage results in low protective coal seams. To inves-tigate this possibility, a 3D stope model is established, which covers three kinds of drill holes. The FLUENT computational fluid mechanics software is used to solve the mass, momentum and species conservation equations of the model. The spatial distributions of oxygen and methane was obtained by calculations and the drainage results of different drill-hole positions were compared. The results show that, from top to bottom, methane dilution by oxygen weakens gradually from the intake to the return side, and methane tends to float; methane and oxygen distribute horizontally. The high-level crossing holes contribute to better methane drainage and a greater level of control. Around these holes, the methane density decreases dramatically and a ‘‘half circle’’ distribution is formed. The methane density decreases on the whole, but a proportion of the methane moves back to deep into the goaf. The research findings provide theoretical grounds for methane drainage.

  9. Effectiveness analysis of methane-drainage by deep-hole controlled pre-splitting blasting for preventing coal and gas outburst

    Institute of Scientific and Technical Information of China (English)

    CAO Shu-gang; LI Yong; LIU Yan-bao; ZHANG Li-qiang; XU A-meng

    2009-01-01

    In the study of the application effectiveness of deep-hole controlled pre-splitting blasting technology, it was found through laboratory micro test and field study on a mine in south China that under the technology, coal masses produce many irreversible cracks. Af-ter blasting, the nearer the distance from blasting hole, the larger the BET surface area and volume ratio of the infiltration pore are; they increased by 11.47% and 5.73%, respec-tively. The coefficient of air permeability is increased 4 times. After 3 months, the gas drainage rate was increased by 66%. In the first 15 days, the cumulative pumped gas was 1.93 times of blasting before. The average absolute gas emission decreased by 63.46%. Experimental results show that deep-hole controlled pre-splitting blasting not only prevents coal and gas outburst, but also gives good economic results.

  10. On a six-parameter generalized Burr XII distribution

    OpenAIRE

    A. K. Olapade

    2008-01-01

    In this paper, we derive a probability density function that generalizes the Burr XII distribution. The cumulative distribution function and the $n^{th}$ moment of the generalized distribution are obtained while the distribution of some order statistics of the distribution are established. A theorem that relate the new distribution to another statistical distribution is established.

  11. Some properties of Gamma Burr type X distribution with application

    Science.gov (United States)

    Khaleel, Mundher Abdullah; Ibrahim, Noor Akma; Shitan, Mahendran; Merovci, Faton

    2016-06-01

    We develop a new continuous distribution called the Gamma-Burr type X (GBX) distribution that extends the Burr type X distribution that has increasing, decreasing and bathtub shapes for the hazard function. Various structural properties of this new distribution are provide, that includes the limit behavior, Quantile function and sub-models. From the generalization of the probability density function and cumulative distribution function of this distribution, the expression for the rth moment, moment generating function, Rényi entropy, and the order statistics can be established. We considered the maximum likelihood estimation to estimate the parameters. A real data set is applied to illustrate the usefulness of the GBX distribution. This new distribution will serve as an alternative model to other models available in the literature for modeling positive real data in many areas.

  12. Geometric Approaches for Reducing Burr Formation in Planar Milling by Avoiding Tool Exits

    OpenAIRE

    Dornfeld, David; Chu, Chih-Hsing

    2005-01-01

    One of the most effective methods for reducing milling exit burrs is to prevent the tool from exiting the workpiece. Exit here refers the condition in which a cutting edge is moving out of the workpiece while removing material. Only entrance burrs can occur under this circumstance, which are usually considered burr-free. This study proposes a set of geometric algorithms for avoiding tool exits in planar milling. Two distinct approaches are developed for tool path planning of 2-D polygons. The...

  13. 基于COMOSOL的顺层钻孔有效抽采半径的数值模拟%Numerical Simulation on Effective Drainage Radius of Drill Hole Along Coal Seam Based on COMSOL

    Institute of Scientific and Technical Information of China (English)

    王兆丰; 李炎涛; 夏会辉; 谭蓉晖

    2012-01-01

    In order to accurately determine the effective drainage radius of drill hole along coal seam, according to the Darcy~ law and the law of conservation of mass as well as the theory of gas flow and occurrence, the gas flow equation of gas extraction drill hole along coal seam was established to study the flow field of coal seam gas around the drilling. Taking Qinxin mine as an example, the gas flow equation was simulated under different drainage negative - pressure and drainage time by using COMSOL software, and the reasonable drainage negative -pressure, drainage time and the effective drainage radius were determined.%为了能够准确地确定顺层瓦斯抽采钻孔的有效抽采半径,以煤层瓦斯赋存及瓦斯流动理论为基础,根据达西定律和质量守恒定律,以钻孔周围煤体瓦斯流动场为研究对象,建立了顺层瓦斯抽采钻孔的瓦斯流动方程,并以沁新煤矿为例,利用COMOSOL软件对抽采钻孔在不同的抽采负压和抽采时间下的瓦斯流动方程进行了数值模拟,确定出了合理的抽采负压、抽采时间及有效抽采半径。

  14. 瓦斯抽放孔射流排水排渣方法及实验研究%Method and Experimental Study on Draining Water and Cinder by Jet in Gas Drainage Hole

    Institute of Scientific and Technical Information of China (English)

    李栋; 卢义玉; 王洁; 廖识; 黄小波

    2012-01-01

    Water and coal cinder in the downward drainage holes influence the effect of gas drainage. A new method is proposed to drain water and coal cinder by jets. A set of device for drain water and cinder by jets is designed. The feasibility of this method is verified by using orthogonal test and the influences of working parameters on the device performance are also researched. The results show that the device performance is most affected by compressed air pressure p. The amount of water and coal cinder increase at first and then reduce as p increases indicates that there exists an optimal air pressure p* making the device performances the best. There is a critical depth Hnp of drainage holes. When the depth of hole is less than Hap, the amount of water and coal cinder keep invariant. However, the amount decreases gradually when the depth of hole is more than Hnp. If all other conditions do not change, the amount of water and coal cinder increase gradually as the water depth in the holes increase. The p* of the device for water and coal cinder drainage is 0.55 Mpa obtained by experiments. The method of draining water and coal cinder by jets is feasible and simple to operate and available to drain water and coal cinder effectively in the drainage holes of coal mine.%针对煤矿俯孔积存水和煤渣影响瓦斯抽放效果问题,提出射流排水排渣方法,设计加工出射流深孔排水排渣装置,采用正交试验法验证了该方法可行性,并研究工作参数对其性能影响规律.结果表明:压缩空气压力p对其性能影响最大,随着p值增大排水渣量呈现先增多后减少趋势,存在最优空气压力值p*使其性能最优;存在临界孔深Hnp,即孔深小于Hnp时排出水渣量保持不变,孔深大于Hnp时排出水渣量逐渐减小;其他条件不变,随着孔内水深升高,排水渣量逐渐增大.射流排水排渣方法可行,操作简单,能有效排出瓦斯抽放孔中的水和煤渣.

  15. Formation of interlayer gap and control of interlayer burr in dry drilling of stacked aluminum alloy plates

    Directory of Open Access Journals (Sweden)

    Tian Wei

    2016-02-01

    Full Text Available In aircraft assembly, interlayer burr formation in dry drilling of stacked metal materials is a common problem. Traditional manual deburring operation seriously affects the assembly quality and assembly efficiency, is time-consuming and costly, and is not conducive to aircraft automatic assembly based on industrial robot. In this paper, the formation of drilling exit burr and the influence of interlayer gap on interlayer burr formation were studied, and the mechanism of interlayer gap formation in drilling stacked aluminum alloy plates was investigated, a simplified mathematical model of interlayer gap based on the theory of plates and shells and finite element method was established. The relationship between interlayer gap and interlayer burr, as well as the effect of feed rate and pressing force on interlayer burr height and interlayer gap was discussed. The result shows that theoretical interlayer gap has a positive correlation with interlayer burr height and preloading pressing force is an effective method to control interlayer burr formation.

  16. Mechanism and management of burr entrapment:A nightmare of interven-tional cardiologists

    Institute of Scientific and Technical Information of China (English)

    Chia-Pin Lin; Ji-Hung Wang; Wen-Ling Lee; Po-Ming Ku; Wei-Hsian Yin; Ten-Ping Tsao; Chi-Jen Chang

    2013-01-01

    Entrapment of the burr within calcified lesion is an uncommon, but serious complication during rotational atherectomy and usually needs surgical retrieval. We report a case series of this complication and also review the possible mechanisms, such as kokesi phenomenon or insufficient pecking motion with decreased rotational speed. We also review the potential techniques ever proposed to rescue this complica-tion percutaneously, including simple manual traction, balloon dilation to release the trap, snaring the burr as distal as possible for forceful local traction and wedging the burr with a child catheter to facilitate retrieval. Gentle pecking motion of the burr for sufficient ablation and shortening the run less than 15 s may avoid such complications. Interventional cardiologists using the rotablator should be familiar with the tips and tricks to avoid and rescue this complication.

  17. Analysis micro-mechanism of burrs formation in the case of nanometric cutting process using numerical simulation method

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Burrs (exit failure), being one of the important factors influencing the final precision of workpiece, have been widely studied. Today, with the development of manufac- turing technology, the depth of cut falls into the range of nanometer or sub- nanometer, there may be some different disciplines dominating the burrs genera- tion process. Molecular dynamics (MD) method, which is different from continuous mechanics, plays an important role in describing microscopic world. Take the ex- ample of single crystal copper, this paper carries out MD analysis micro-mecha- nism of burrs generation process. The results show that the burrs geometry de- pends on the type of workpiece (ductile or brittle). The depth of cut is decreased in the case of positive burrs generation process while the depth of cut is increased in case of negative burrs generation process.

  18. 瓦斯抽放煤层增透深孔聚能爆破钻孔参数%Drilling parameters of deep-hole cumulative blasting to improve coal seam permeability in gas drainage

    Institute of Scientific and Technical Information of China (English)

    郭德勇; 吕鹏飞; 单智勇; 谢安

    2013-01-01

    以焦作煤业集团九里山矿煤层深孔聚能爆破试验为基础,利用数值模拟分析了爆破煤体应力变化规律,发现聚能爆破效应导致应力峰值增大,扩大了煤体裂隙区范围.同时对聚能爆破钻孔参数进行优化,确定了合理的炮孔直径、爆破孔间距、爆破孔与邻近抽放孔及煤层顶底板间距.现场试验结果表明:优化的钻孔参数不仅使聚能爆破增透效果显著而且保证了爆破过程的安全.%Based on coal seam deep-hole cumulative blasting experiments in Jiulishan Coal Mine of Jiaozuo Coal Group, the law of stress change in a blasting coal body was analyzed by numerical simulation. It is found that cumulative blasting effect leads to the increase of peak stress and enlarges the crack zone range of the coal body. Drilling parameters for cumulative blasting, such as blast hole diameter, blast hole spacing, distance between the blast hole and the adjacent gas drainage hole, and distance from the blast hole to the coal seam roof and floor, were determined by optimization. Field experimental results show that after using these optimized drilling parameters the cumulative blasting not only gets remarkable permeability increasing effect but also ensures blasting safety.

  19. The Construction of Leadership Images in the Popular Press: The Case of Donald Burr and People Express.

    Science.gov (United States)

    Chen, Chao C.; Meindl, James R.

    1991-01-01

    To explore social construction of leadership, one study examined the rise and fall of Donald Burr and People Express Airline, a celebrated saga in entrepreneurship. Content analyses of image descriptions and metaphors projected by the popular press revealed that Burr's image was reconstructed to account for the dramatic performance failure of the…

  20. Analysis on Handling Method for Sand Hole in Lubricating Water Pipeline of Seepage Drainage Pump%渗漏排水泵润滑水管路沙眼的处理方法分析

    Institute of Scientific and Technical Information of China (English)

    黄永华

    2013-01-01

    通过介绍对万家寨水电站渗漏排水泵润滑水管沙眼问题的处理方法,分析了设计选材、地面施工质量以及混凝土中埋设管路根部防锈等问题。经过处理,万家寨水电站设备运行安全、可靠、高效。%In this paper, the handling method for sand hole in the lubricating water pipeline of seepage drainage pump of Wanjiazhai Hy-dropower Station is introduced.Furthermore, handling material selection, ground construction quality and rust protection of the root of the pipeline buried in concrete are analyzed.Through the treatment, Wanjiazhai Hydropower Station operates safely, reliably and in high effi-ciency.

  1. 慢性硬脑膜下血肿钻孔引流术后并发症的防治对比研究及文献复习%Prevention and treatment of surgical complications of burr-hole drainage for chronic subdural hematoma-a comparative study and literature review

    Institute of Scientific and Technical Information of China (English)

    罗晟; 何永生

    2016-01-01

    目的 探讨慢性硬脑膜下血肿(chronic subdural hematoma,CSDH)手术后并发症的类型及其防治措施.方法 回顾性分析2003~ 2015年268例CSDH患者的临床资料,对术后并发症发生情况进行统计分析.结果 268例手术患者中出现并发症83例,发生率30.9%.常见并发症包括:颅内积气33例,硬膜下积液12例,脑复张不良13例,血肿复发4例,颅内血肿4例,脑脊液漏及低颅压4例;少见并发症有:引流管导致脑损伤2例,术中和术后癫痫各1例,脑梗死1例,术后精神障碍4例,钻孔引流失败2例,头皮感染1例,肺部感染死亡1例.格拉斯哥预后评分(GOS)恢复良好165例,偏瘫2例,死亡1例.改良术式组的并发症发生率显著低于常规术式组,差异有显著统计学意义(P<0.01),两组间GOS预后评分及平均住院日比较差异无统计学意义(P>0.05).结论 针对CSDH患者进行个体化围术期管理,选择恰当的手术时机并作合理的技术改进,是提高CSDH患者治愈率,降低并发症发生率的关键.

  2. Perindopril and residual chronic subdural hematoma volumes six weeks after burr hole surgery

    DEFF Research Database (Denmark)

    Poulsen, Frantz Rom; Munthe, Sune; Søe, Morten;

    2014-01-01

    OBJECTIVE: Recurrence rates of between 5% and 25% have been reported following surgery for chronic subdural hematoma (CSH). A previous study showed that the treatment with angiotensin converting enzyme (ACE) inhibitors decreases the risk of recurrence. To test the effects of ACE inhibitors...... perindopril 5mg or placebo treatment daily for three months prior to surgery. Cerebral CT scans were performed after six weeks, and clinical follow-ups were performed three months after surgery. Additionally, a retrospective analysis of the data and CT scans from all nonrandomized patients from the same time...... surgery revealed no difference between the placebo and perindopril-treated groups. In the retrospective group (245 patients), there was no correlation between the risk of recurrence and ACE inhibitor treatment. CONCLUSION: Our data suggest that perindopril does not diminish the size of residual CSHs six...

  3. Formation of interlayer gap and control of interlayer burr in dry drilling of stacked aluminum alloy plates

    Institute of Scientific and Technical Information of China (English)

    Tian Wei; Hu Jian; Liao Wenhe; Bu Yin; Zhang Lin

    2016-01-01

    In aircraft assembly, interlayer burr formation in dry drilling of stacked metal materials is a common problem. Traditional manual deburring operation seriously affects the assembly qual-ity and assembly efficiency, is time-consuming and costly, and is not conducive to aircraft automatic assembly based on industrial robot. In this paper, the formation of drilling exit burr and the influ-ence of interlayer gap on interlayer burr formation were studied, and the mechanism of interlayer gap formation in drilling stacked aluminum alloy plates was investigated, a simplified mathematical model of interlayer gap based on the theory of plates and shells and finite element method was established. The relationship between interlayer gap and interlayer burr, as well as the effect of feed rate and pressing force on interlayer burr height and interlayer gap was discussed. The result shows that theoretical interlayer gap has a positive correlation with interlayer burr height and preloading pressing force is an effective method to control interlayer burr formation.

  4. Design study of the geometry of the blanking tool to predict the burr formation of Zircaloy-4 sheet

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Jisun, E-mail: nskim@sogang.ac.kr; Lee, Hyungyil, E-mail: nskim@sogang.ac.kr; Kim, Dongchul, E-mail: nskim@sogang.ac.kr; Kim, Naksoo, E-mail: nskim@sogang.ac.kr [Sogang University, Department of Mechanical Engineering, Seoul, 121-742 (Korea, Republic of)

    2013-12-16

    In this work, we investigated factors that influence burr formation for zircaloy-4 sheet used for spacer grids of nuclear fuel roads. Factors we considered are geometric factors of punch. We changed clearance and velocity in order to consider the failure parameters, and we changed shearing angle and corner radius of L-shaped punch in order to consider geometric factors of punch. First, we carried out blanking test with failure parameter of GTN model using L-shaped punch. The tendency of failure parameters and geometric factors that affect burr formation by analyzing sheared edges is investigated. Consequently, geometric factor's influencing on the burr formation is also high as failure parameters. Then, the sheared edges and burr formation with failure parameters and geometric factors is investigated using FE analysis model. As a result of analyzing sheared edges with the variables, we checked geometric factors more affect burr formation than failure parameters. To check the reliability of the FE model, the blanking force and the sheared edges obtained from experiments are compared with the computations considering heat transfer.

  5. Design study of the geometry of the blanking tool to predict the burr formation of Zircaloy-4 sheet

    Science.gov (United States)

    Ha, Jisun; Lee, Hyungyil; Kim, Dongchul; Kim, Naksoo

    2013-12-01

    In this work, we investigated factors that influence burr formation for zircaloy-4 sheet used for spacer grids of nuclear fuel roads. Factors we considered are geometric factors of punch. We changed clearance and velocity in order to consider the failure parameters, and we changed shearing angle and corner radius of L-shaped punch in order to consider geometric factors of punch. First, we carried out blanking test with failure parameter of GTN model using L-shaped punch. The tendency of failure parameters and geometric factors that affect burr formation by analyzing sheared edges is investigated. Consequently, geometric factor's influencing on the burr formation is also high as failure parameters. Then, the sheared edges and burr formation with failure parameters and geometric factors is investigated using FE analysis model. As a result of analyzing sheared edges with the variables, we checked geometric factors more affect burr formation than failure parameters. To check the reliability of the FE model, the blanking force and the sheared edges obtained from experiments are compared with the computations considering heat transfer.

  6. Economic Reliability Acceptance Sampling Plans from Truncated Life Tests based on the Burr Type XII Percentiles

    Directory of Open Access Journals (Sweden)

    Abdur Razzaque Mughal (Corresponding Author

    2011-09-01

    Full Text Available In this article, economic reliability acceptance sampling plan (ERASP is developed for the Burr type XII distribution when the life test is truncated at pre-specified designed parameters. The minimum termination time is necessary to ensure that the specified life percentile is found under a given producer’s risk. The operating characteristic values of the proposed plan are presented for various parameters. A comparative study of proposedplan and existing plan developed by Lio et al. (2010 is also discussed. The result is illustrated by a real dataset example.

  7. Information and Covariance Matrices for Multivariate Burr III and Logistic distributions

    CERN Document Server

    Yari, G; Yari, Gholamhossein; Mohammad-Djafari, Ali

    2004-01-01

    Main result of this paper is to derive the exact analytical expressions of information and covariance matrices for multivariate Burr III and logistic distributions. These distributions arise as tractable parametric models in price and income distributions, reliability, economics, populations growth and survival data. We showed that all the calculations can be obtained from one main moment multi dimensional integral whose expression is obtained through some particular change of variables. Indeed, we consider that this calculus technique for improper integral has its own importance in applied probability calculus.

  8. REMOVAL OF ADDED NITRATE IN COTTON BURR COMPOST, MULCH COMPOST, AND PEAT: MECHANISMS AND POTENTIAL USE FOR GROUNDWATER NITRATE REMEDIATION

    Science.gov (United States)

    We conducted batch tests on the nature and kinetics of removal of added nitrate in cotton burr compost, mulch compost, and sphagnum peat that may be potentially used in a permeable reactive barrier (PRB) for groundwater nitrate remediation. A rigorous steam autoclaving protocol (...

  9. Long-term performance of thermoplastic composite material with cotton burr and stem (CBS) as a partial filler

    Science.gov (United States)

    Rationale: Cotton burr and stem (CBS) fraction of cotton gin byproducts has shown promise as a fiber filler in thermoplastic composites, with physical and mechanical properties comparable to that made with wood fiber fillers. However, the long-term performance of this composite material is not known...

  10. [Peculiar "chestnuts in burrs" formation in MGIT cultures of pulmonary Mycobacterium xenopi cases].

    Science.gov (United States)

    Abe, Keiko; Yamazato, Masaya; Ohtani, Sumire; Shinozawa, Youko; Nakamura, Haruki; Miura, Takao; Hasegawa, Naoki; Hara, Masamichi

    2007-12-01

    We report 3 patients whose sputum and bronchoalveolar lavage fluid (BALF) cultures for acid fast bacteria in MGIT liquid media grew colonies of Mycobacterium xenopi (M. xenopi) with a characteristic chestnut burr like appearance. Patients I, II, and III were a 74-year-old man, 47-year-old woman, and 62-year-old woman, respectively. Chest X ray showed a pulmonary cavity in each case. Patient I had a history of pulmonary and renal tuberculosis. The past medical history of patient II was unremarkable. Patient III had a history of lung cancer. Eight sputum samples and 4 BALF samples from patient I, 3 sputum samples and 1 BALF sample from patient II, and 4 sputum samples from patient III were positive for acid fast bacteria, and the organism was identified as M. xenopi in 9 samples. Smears of these MGIT-positive cultures were stained by the Ziehl Neelsen method, and examined under a microscope. Large and small, spherical shaped, 15-100 microm clusters of thin, elongated bacteria, with a chestnut burr-like or spherical moss like and partly budding appearance, were scattered throughout the smear preparation. Although only 34 cases of M. xenopi infection were reported in Japan between 1984 and 2005, the number of reported cases has been on the increase in recent years. Since no report from Japan, Europe, or the United States have noted the characteristic appearance of M. xenopi in cultures, we consider that the feature described in this communication is useful to presumptively identify M. xenopi.

  11. [Little Dry Creek Drainage

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Map of the drainage boundary, direction of flow, canals and ditches, and streets for the drainage study plan and profile for Little Dry Creek sub area in the North...

  12. Percutaneous Abscess Drainage

    Science.gov (United States)

    ... Physician Resources Professions Site Index A-Z Percutaneous Abscess Drainage An abscess is an infected fluid collection ... are the benefits vs. risks? What is Percutaneous Abscess Drainage? An abscess is an infected fluid collection ...

  13. Transient drainage summary report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    This report summarizes the history of transient drainage issues on the Uranium Mill Tailings Remedial Action (UMTRA) Project. It defines and describes the UMTRA Project disposal cell transient drainage process and chronicles UMTRA Project treatment of the transient drainage phenomenon. Section 4.0 includes a conceptual cross section of each UMTRA Project disposal site and summarizes design and construction information, the ground water protection strategy, and the potential for transient drainage.

  14. Foam consolidation and drainage.

    Science.gov (United States)

    Jun, S; Pelot, D D; Yarin, A L

    2012-03-27

    A theoretical model of foam as a consolidating continuum is proposed. The general model is applied to foam in a gravity settler. It is predicted that liquid drainage from foam in a gravity settler begins with a slow drainage stage. Next, a stage with faster drainage occurs where the drainage rate doubles compared to the initial stage. The experiments conducted within the framework of this work confirmed the theoretical predictions and allowed measurements of foam characteristics. Foams of three different concentrations of Pantene Pro-V Classic Care Solutions shampoo were studied, as well as the addition of polyethylene oxide (PEO) in one case. The shampoo's main foaming components are sodium lauryl sulfate and sodium laureth sulfate. It is shown to what extent foam drainage is slowed down by using higher shampoo concentrations and how it is further decreased by adding polymer (PEO).

  15. 改良T管引流与传统硬脑膜下引流治疗慢性硬脑膜下血肿的效果比较%Comparison of modified T tube drainage therapy with traditional skull drill-hole therapy

    Institute of Scientific and Technical Information of China (English)

    孙峻峰; 熊东胜; 高强; 郑维涛; 李康; 赵鑫; 康宁

    2016-01-01

    Objective:To compare modified T tube therapy with traditional skull drill-hole therapy in pa-tients with chronic subdural hematoma .Methods:This study collected 167 cases from June 2008 to June 2015 .The patients were divided into two groups .The remnant gas and liquid ,drainage time ,hospitalization time were com-pared between the two groups .Results:We found patients after modified T tube therapy had less remnant gas and liquid ,drainage time decreased from 3-5 days to 2-3 days ,hospitalization time decreased from 12-14 days to 9-10 days .Conclusion :Modified T tube therapy has less remnant gas and liquid than traditional skull drill-hole therapy , better impact for brain restoration ,decreased drainage time and hospitalization time .It has a better therapeutic effect .%目的:探讨在慢性硬脑膜下血肿颅骨钻孔手术治疗中,改良 T 管引流相比传统硬脑膜下引流的优劣。方法:本次研究回顾分析了我院慢性硬脑膜下血肿行颅骨钻孔手术167例,分为2组,改良T 管引流组96例,传统硬脑膜下引流组71例,统计比较了2组患者在术后残余积液及积气量、引流管保留时间、住院时间等情况,以评估治疗的效果。结果:改良T管引流较传统硬脑膜下引流对慢性硬脑膜下血肿的治疗,术后残余积液、积气量减少,留管时间由3~5d减少为2~3d ,住院时间由12~14d减少为9~10d。结论:改良 T 管引流相比传统硬脑膜下引流术后残余积液、积气量小,有利于脑组织膨复,缩短引流管保留时间和住院时间,有更好的治疗效果。

  16. Agricultural Drainage Well Intakes

    Data.gov (United States)

    Iowa State University GIS Support and Research Facility — Locations of surface intakes for registered agriculture drainage wells according to the database maintained by IDALS. Surface intakes were located from their...

  17. Surface Water & Surface Drainage

    Data.gov (United States)

    Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

  18. Airport Pavement Drainage

    Science.gov (United States)

    1990-06-01

    drainage layer and trench drains can be found in Cedergren (10). 4.2 COMPONENTS OF SUBSURFACE DRAINAGE SYSTEM 4.2.1 Outflow Once the water has found...According to Cedergren (10) the open graded aggregate can replace the normally used dense graded materials on an inch-for-inch basis. A main problem in...the perforated pipe to prevent fines from entering, Figure 4.24 (11). Cedergren (10) suggests that collector pipes should be 42 laid with the

  19. Black Holes

    Science.gov (United States)

    Luminet, Jean-Pierre

    1992-09-01

    Foreword to the French edition; Foreword to the English edition; Acknowledgements; Part I. Gravitation and Light: 1. First fruits; 2. Relativity; 3. Curved space-time; Part II. Exquisite Corpses: 4. Chronicle of the twilight years; 5. Ashes and diamonds; 6. Supernovae; 7. Pulsars; 8. Gravitation triumphant; Part III. Light Assassinated: 9. The far horizon; 10. Illuminations; 11. A descent into the maelstrom; 12. Map games; 13. The black hole machine; 14. The quantum black hole; Part IV. Light Regained: 15. Primordial black holes; 16. The zoo of X-ray stars; 17. Giant black holes; 18. Gravitational light; 19. The black hole Universe; Appendices; Bibliography; Name index; Subject index.

  20. Wound Drainage Culture (For Parents)

    Science.gov (United States)

    ... Your 1- to 2-Year-Old Wound Drainage Culture KidsHealth > For Parents > Wound Drainage Culture Print A A A What's in this article? ... de heridas What It Is A wound drainage culture is a test to detect germs such as ...

  1. Acid mine drainage

    Science.gov (United States)

    Bigham, Jerry M.; Cravotta, Charles A.

    2016-01-01

    Acid mine drainage (AMD) consists of metal-laden solutions produced by the oxidative dissolution of iron sulfide minerals exposed to air, moisture, and acidophilic microbes during the mining of coal and metal deposits. The pH of AMD is usually in the range of 2–6, but mine-impacted waters at circumneutral pH (5–8) are also common. Mine drainage usually contains elevated concentrations of sulfate, iron, aluminum, and other potentially toxic metals leached from rock that hydrolyze and coprecipitate to form rust-colored encrustations or sediments. When AMD is discharged into surface waters or groundwaters, degradation of water quality, injury to aquatic life, and corrosion or encrustation of engineered structures can occur for substantial distances. Prevention and remediation strategies should consider the biogeochemical complexity of the system, the longevity of AMD pollution, the predictive power of geochemical modeling, and the full range of available field technologies for problem mitigation.

  2. Predicting tile drainage discharge

    DEFF Research Database (Denmark)

    Iversen, Bo Vangsø; Kjærgaard, Charlotte; Petersen, Rasmus Jes;

    of the water load coming from the tile drainage system is therefore essential. This work aims at predicting tile drainage discharge using dynamic as well as a statistical predictive models. A large dataset of historical tile drain discharge data, daily discharge values as well as yearly average values were......More than 50 % of Danish agricultural areas are expected to be artificial tile drained. Transport of water and nutrients through the tile drain system to the aquatic environment is expected to be significant. For different mitigation strategies such as constructed wetlands an exact knowledge...... used in the analysis. For the dynamic modelling, a simple linear reservoir model was used where different outlets in the model represented tile drain as well as groundwater discharge outputs. This modelling was based on daily measured tile drain discharge values. The statistical predictive model...

  3. 高频直缝焊管内毛刺清除装置设计改进%Improvement of HF Longitudinal Welded Pipe Inside Burr Removing Device

    Institute of Scientific and Technical Information of China (English)

    韩子元; 杜广来; 祁云祥; 祖建江; 轧乃姜

    2011-01-01

    介绍了高频直缝焊管内毛刺清除的主要方式,对天津双街钢管有限公司φ325 mm机组原有机械刮削式内毛刺清除装置的结构形式及优缺点进行了分析.研究设计了新型液压升降刮削式内毛刺清除装置,对其周向调整结构、无油润滑轴承、刀具冷却方式和内毛刺余高检测方法等创新点进行了详细的阐述.经过实际生产应用,这种新型液压升降式内毛刺清除装置刮削质量更稳定,轴承套和刀具的使用成本更低,操作方便,经济实用,在高频直缝焊管生产行业中有很好的推广价值.%The main removing insdie burr methods on high frequency longitudinal welded pipe were introduced; the structure, advantages and disadvantages of original mechanical scraping inside burr removing device of 325 units in Tianjin Shuangjie Steel Pipe Co., Ltd. were analyzed. A new kind of hydraulic lifting and scraping inside burr removing device was designed and studied, and several innovative points were expatiated, covering the circumferential adjusting structure, bearing without oil lubrication, cutter cooling mode, detecting method of inside burr reinforcement and so on.The practical application proved that this new device possesses stable quality, lower cost for bearing and cutter,operation convenience, so it is applicable to widely promote in high frequency longitudinal welded pipe industry.

  4. Optimization of Burr size, Surface Roughness and Circularity Deviation during Drilling of Al 6061 using Taguchi Design Method and Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Reddy Sreenivasulu

    2015-03-01

    Full Text Available This paper presents the influence of cutting parameters like cutting speed, feed rate, drill diameter, point angle and clearance angle on the burr size, surface roughness and circularity deviation of Al 6061 during drilling on CNC vertical machining center. A plan of experiments based on Taguchi technique has been used to acquire the data. An orthogonal array, signal to noise (S/N ratio and analysis of variance (ANOVA are employed to investigate machining characteristics of Al 6061 using HSS twist drill bits of variable tool geometry and maintain constant helix angle of 45 degrees. Confirmation tests have been carried out to predict the optimal setting of process parameters to validate the used approach, obtained the values of 0.2618mm, 0.1821mm, 3.7451µm, 0.0676mm for burr height, burr thickness, surface roughness and circularity deviation respectively. Finally, artificial neural network has been applied to compare the predicted values with the experimental values, good agreement was shown between the predictive model results and the experimental measurements. Normal 0 false false false EN-US X-NONE X-NONE

  5. 3D Finite Element Modelling of Cutting Forces in Drilling Fibre Metal Laminates and Experimental Hole Quality Analysis

    Science.gov (United States)

    Giasin, Khaled; Ayvar-Soberanis, Sabino; French, Toby; Phadnis, Vaibhav

    2016-07-01

    Machining Glass fibre aluminium reinforced epoxy (GLARE) is cumbersome due to distinctively different mechanical and thermal properties of its constituents, which makes it challenging to achieve damage-free holes with the acceptable surface quality. The proposed work focuses on the study of the machinability of thin (~2.5 mm) GLARE laminate. Drilling trials were conducted to analyse the effect of feed rate and spindle speed on the cutting forces and hole quality. The resulting hole quality metrics (surface roughness, hole size, circularity error, burr formation and delamination) were assessed using surface profilometry and optical scanning techniques. A three dimensional (3D) finite-element (FE) model of drilling GLARE laminate was also developed using ABAQUS/Explicit to help understand the mechanism of drilling GLARE. The homogenised ply-level response of GLARE laminate was considered in the FE model to predict cutting forces in the drilling process.

  6. 基于毛刺的切削参数优化试验研究%Experimental Study of Optimization Cutting Parameters for Burr

    Institute of Scientific and Technical Information of China (English)

    王建强

    2011-01-01

    金属切削中的毛刺是切削加工中产生的常见现象,它严重地影响产品的精度和使用性,有必要对毛刺的预测进行深入的研究.本文针对铣槽时产生的出口毛刺高度进行试验与检测,并通过田口直交表进行统计分析,对检测到的试验数据运用相关公式进一步进行计算优化,然后根据传统的经验值与优化计算的数据进行比较,获取了以毛刺高度为控制对象的切削用量优化值,以此为依据提出在加工过程中夹具、机床等相关的数据优化,为进一步对毛刺控制的非线性数学模型的建立提供试验数据.%The formation of burr is a common phenomenon in metal cutting , the existence of hurr affects machining accuracy and performance of parts, so it is very necessary to study burr controlling and prediction systematically. In this paper,the experiment is conducted in slot milling to investigate the height of burr, and the orthogonal experiment is built by the Taguchi method. Detected the experiment data by using relevant calculation formula of further optimized, and then according to the tradition of the experience and the optimization calculation, the Taguchi method is used to obtain the optical cutting parameters to reduce burr height. Based on the machining process fixture, machine tool, the relevant data, which can provides experimental data in building a non-linear mathematics model to predict burr height.

  7. Sustainable Drainage Systems

    Directory of Open Access Journals (Sweden)

    Miklas Scholz

    2015-05-01

    Full Text Available Urban water management has somewhat changed since the publication of The Sustainable Drainage System (SuDS Manual in 2007 [1], transforming from building traditional sewers to implementing SuDS, which are part of the best management practice techniques used in the USA and seen as contributing to water-sensitive urban design in Australia. Most SuDS, such as infiltration trenches, swales, green roofs, ponds, and wetlands, address water quality and quantity challenges, and enhance the local biodiversity while also being acceptable aesthetically to the public. Barriers to the implementation of SuDS include adoption problems, flood and diffuse pollution control challenges, negative public perception, and a lack of decision support tools addressing, particularly, the retrofitting of these systems while enhancing ecosystem services. [...

  8. A newly developed open-end intracranial hematoma drainage tube

    Institute of Scientific and Technical Information of China (English)

    Chao He; Nongnaphat Wanussakul; Dong Yang; Tianya Wu; Ming Zhao

    2016-01-01

    Methods:The newly developed device consists of two parts:the plunger and barrel. On one side, the barrel is bullet shaped with an opening tip. The plunger is located in the middle cavity of the tube barrel and extended out at the open-end. It was designed for strengthening the tube barrel and for convenience in performing the drainage procedure. It can be used by inserting the drainage tube into the lesion and pulling out the plunger, whereby blood will forcefully rise up inside the barrel, providing a satisfactory outcome. It is made for effusion drainage purposes. During the procedure, the drainage tip is placed at the deepest part of the intracranial hematoma to completely drain the blood. Moreover, the plunger fits tightly in the tube, preventing leakage during the operation. With the use of the device, brain can be separated. In addition, the device can help reduce the risk of cerebral damage because of the small operating area. The barrel sidewall has matching opening holes bilaterally and equally for exchanging substances between the inner and outer parts. The overlapping ratio in each horizontal pair is around 1/3–1/2. Each pair on the opposite side will form a different pressure. Thus, the opening holes will not easily get blocked with blood clot. Results: Blood and accumulated liquid from the deepest part of the intracranial hematoma can be directly drawn through the drainage tube without damaging a large area. The tube does not get blocked easily and allows for complete removal of the hematoma. Conclusions:The device is asuitable instrument for clinical application.

  9. Black holes

    CERN Document Server

    Chrúsciel, P T

    2002-01-01

    This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usual one for gravity, and leads to the one associated with the Unruh metric in the case of Euler equations. We review the global conditions which have been used in the Scri-based definition of a black hole and point out the deficiencies of the Scri approach. Various results on the structure of horizons and apparent horizons are presented, and a new proof of semi-convexity of horizons based on a variational principle is given. Recent results on the classification of stationary singularity-free vacuum solutions are reviewed. ...

  10. Laser surface texturing of cast iron steel: dramatic edge burr reduction and high speed process optimisation for industrial production using DPSS picosecond lasers

    Science.gov (United States)

    Bruneel, David; Kearsley, Andrew; Karnakis, Dimitris

    2015-07-01

    In this work we present picosecond DPSS laser surface texturing optimisation of automotive grade cast iron steel. This application attracts great interest, particularly in the automotive industry, to reduce friction between moving piston parts in car engines, in order to decrease fuel consumption. This is accomplished by partially covering with swallow microgrooves the inner surface of a piston liner and is currently a production process adopting much longer pulse (microsecond) DPSS lasers. Lubricated interface conditions of moving parts require from the laser process to produce a very strictly controlled surface topography around the laser formed grooves, whose edge burr height must be lower than 100 nm. To achieve such a strict tolerance, laser machining of cast iron steel was investigated using an infrared DPSS picosecond laser (10ps duration) with an output power of 16W and a repetition rate of 200 kHz. The ultrashort laser is believed to provide a much better thermal management of the etching process. All studies presented here were performed on flat samples in ambient air but the process is transferrable to cylindrical geometry engine liners. We will show that reducing significantly the edge burr below an acceptable limit for lubricated engine production is possible using such lasers and remarkably the process window lies at very high irradiated fluences much higher that the single pulse ablation threshold. This detailed experimental work highlights the close relationship between the optimised laser irradiation conditions as well as the process strategy with the final size of the undesirable edge burrs. The optimised process conditions are compatible with an industrial production process and show the potential for removing extra post)processing steps (honing, etc) of cylinder liners on the manufacturing line saving time and cost.

  11. Filter Fabrics for Airport Drainage.

    Science.gov (United States)

    1979-09-01

    Systems for *r- field Pavements," Harry R. Cedergren . d. "Development of Guidelines for the Design of Subsurfac( Drainage Systems for Highway Pavement...Structural 4Sectic s," H. R. Cedergren , J. A. Arman, and K. H. O’Brien. e. Drainage of Highway and Airfield Pavements, Harry R. Cedergren .> Five...by Cedergren (974).5 Additionally, several references were used, particularly those describing experimental anu construction prolects using filter

  12. Coronal Holes

    Directory of Open Access Journals (Sweden)

    Steven R. Cranmer

    2009-09-01

    Full Text Available Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations, and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are established in the extended corona. For example, the importance of kinetic plasma physics and turbulence in coronal holes has been affirmed by surprising measurements from the UVCS instrument on SOHO that heavy ions are heated to hundreds of times the temperatures of protons and electrons. These observations point to specific kinds of collisionless Alfvén wave damping (i.e., ion cyclotron resonance, but complete theoretical models do not yet exist. Despite our incomplete knowledge of the complex multi-scale plasma physics, however, much progress has been made toward the goal of understanding the mechanisms ultimately responsible for producing the observed properties of coronal holes.

  13. Correlation of microstructure, tensile properties and hole expansion ratio in cold rolled advanced high strength steels

    Science.gov (United States)

    Terrazas, Oscar R.

    The demand for advanced high strength steels (AHSS) with higher strengths is increasing in the automotive industry. While there have been major improvements recently in the trade-off between ductility and strength, sheared-edge formability of AHSS remains a critical issue. AHSS sheets exhibit cracking during stamping and forming operations below the predictions of forming limits. It has become important to understand the correlation between microstructure and sheared edge formability. The present work investigates the effects of shearing conditions, microstructure, and tensile properties on sheared edge formability. Seven commercially produced steels with tensile strengths of 1000 +/- 100 MPa were evaluated: five dual-phase (DP) steels with different compositions and varying microstructural features, one trip aided bainitic ferrite (TBF) steel, and one press-hardened steel tempered to a tensile strength within the desired range. It was found that sheared edge formability is influenced by the martensite in DP steels. Quantitative stereology measurements provided results that showed martensite size and distribution affect hole expansion ratio (HER). The overall trend is that HER increases with more evenly dispersed martensite throughout the microstructure. This microstructure involves a combination of martensite size, contiguity, mean free distance, and number of colonies per unit area. Additionally, shear face characterization showed that the fracture and burr region affect HER. The HER decreases with increasing size of fracture and burr region. With a larger fracture and burr region more defects and/or micro-cracks will be present on the shear surface. This larger fracture region on the shear face facilitates cracking in sheared edge formability. Finally, the sheared edge formability is directly correlated to true fracture strain (TFS). The true fracture strain from tensile samples correlates to the HER values. HER increases with increasing true fracture strain.

  14. DRAINAGE AND FLEXIBLE PAVEMENT PERFORMANCE

    Directory of Open Access Journals (Sweden)

    SIDDHARTHA ROKADE

    2012-04-01

    Full Text Available Providing adequate drainage to a pavement system has been considered as an important design consideration to prevent premature failures due to water related problems such as pumping action, loss of support, and rutting, among others. Most water in pavements is due to rainfall infiltration into unsaturated pavement layers, throughjoints, cracks, shoulder edges, and various other defects, especially in older deteriorated pavements. Water also seep upward from a high groundwater table due to capillary suction or vapour movements, or it may flow laterally from the pavement edges and side ditches. Providing adequate drainage to a pavement system has been considered as an important design consideration to ensure satisfactory performance of the pavement, particularly from the perspective of life cycle cost and serviceability. To minimize premature pavement distresses and to enhance the pavement performance, it is imperative to provide adequate drainage to allow infiltrated water to drain out from the base and sub-base, thus avoiding saturation of base and subgrade soils. This paper deals with the analysis of the impact of subsurface drainage on pavement system performance. The requirement ofeffective subsurface drainage for pavement performance is also discussed.

  15. Coronal Holes

    CERN Document Server

    Cranmer, Steven R

    2009-01-01

    Coronal holes are the darkest and least active regions of the Sun, as observed both on the solar disk and above the solar limb. Coronal holes are associated with rapidly expanding open magnetic fields and the acceleration of the high-speed solar wind. This paper reviews measurements of the plasma properties in coronal holes and how these measurements are used to reveal details about the physical processes that heat the solar corona and accelerate the solar wind. It is still unknown to what extent the solar wind is fed by flux tubes that remain open (and are energized by footpoint-driven wave-like fluctuations), and to what extent much of the mass and energy is input intermittently from closed loops into the open-field regions. Evidence for both paradigms is summarized in this paper. Special emphasis is also given to spectroscopic and coronagraphic measurements that allow the highly dynamic non-equilibrium evolution of the plasma to be followed as the asymptotic conditions in interplanetary space are establish...

  16. Dumb holes: analogues for black holes.

    Science.gov (United States)

    Unruh, W G

    2008-08-28

    The use of sonic analogues to black and white holes, called dumb or deaf holes, to understand the particle production by black holes is reviewed. The results suggest that the black hole particle production is a low-frequency and low-wavenumber process.

  17. Analysis on Burr Formation of Pantyhose Packaging Bag%裤袜包装袋毛刺形成原因分析

    Institute of Scientific and Technical Information of China (English)

    吴世青; 孟婥; 孙志军; 李培兴

    2012-01-01

    针对裤袜包装机自动成袋系统制袋出现毛刺的问题,建立了塑料薄膜热变形的数学模型,采用ANSYS软件对热封切刀片进行有限元分析,得到了影响热封切刀片温度分布的因素;把所得到的不同温度场作为载荷作用在塑料薄膜上,得到了塑料薄膜在不同温度载荷下的热变形位移,通过对比分析得出裤袜包装袋毛刺形成的主要原因是塑料薄膜的热膨胀与热应力.热膨胀与热应力主要与温度有关,通过测量在一系列温度载荷下塑料薄膜的热变形位移,得到了热封切刀片的最佳温度范围,使得塑料薄膜热膨胀与热应力最小,有效抑制了毛刺的形成.%The mathematical model of plastic film thermal deformation was established for the burr problem in the automatically bag making system of pantyhose packaging machine, the factors that affect the temperature distribution of the heat sealing and cutting blade were obtained using finite elements analysis software ANSYS; loading the different temperature fields on the plastic film, the thermal deformation displacement of the plastic film under different temperature load was obtained, by comparing, it can be obtained that the main causes of burrs formation were the thermal expansion and thermal stress of the plastic film. Thermal expansion and thermal stress were related to temperature. The optimum temperature range of the heat sealing and cutting blade were obtained by measuring the thermal deformation of the plastic film under a series of temperature loads, so that the thermal expansion and thermal stress can be the minimum, effectively restraining the formation of burrs.

  18. Percutaneous drainage of abdominal abcess

    Energy Technology Data Exchange (ETDEWEB)

    Men, Sueleyman E-mail: suleyman.men@deu.edu.tr; Akhan, Okan; Koeroglu, Mert

    2002-09-01

    The mortality in undrained abdominal abscesses is high with a mortality rate ranging between 45 and 100%. The outcome in abdominal abscesses, however, has improved due to advances in image guided percutaneous interventional techniques. The main indications for the catheter drainage include treatment or palliation of sepsis associated with an infected fluid collection, and alleviation of the symptoms that may be caused by fluid collections by virtue of their size, like pancreatic pseudocele or lymphocele. The single liver abscesses may be drained with ultrasound guidance only, whereas the multiple abscesses usually require computed tomography (CT) guidance and placement of multiple catheters. The pancreatic abscesses are generally drained routinely and urgently. Non-infected pancreatic pseudocysts may be simply observed unless they are symptomatic or cause problems such as pain or obstruction of the biliary or the gastrointestinal tract. Percutaneous routes that have been described to drain pelvic abscesses include transrectal or transvaginal approach with sonographic guidance, a transgluteal, paracoccygeal-infragluteal, or perineal approach through the greater sciatic foramen with CT guidance. Both the renal and the perirenal abscesses are amenable to percutaneous drainage. Percutaneous drainage provides an effective and safe alternative to more invasive surgical drainage in most patients with psoas abscesses as well.

  19. Innovative Method for Preventing Micro Burr Formation in Micro Milling%微细铣削加工中抑制微毛刺生成的新方法

    Institute of Scientific and Technical Information of China (English)

    寇兆军; 万熠; 蔡玉奎; 王滕; 刘战强

    2015-01-01

    In micro milling process of micro parts, the formation of micro burr is an important factor affecting the quality of micro parts. An innovative method to prevent micro burrs formation was proposed in this paper, mainly by con-structing auxiliary support. Burrs formation mechanism was analysed and it was found that the scale effect and plastic de-formation of the workpiece material in micro milling plays a critical role in burrs generation, especially near the workpiece boundaries. The stiffness of the workpiece boundary was improved by constructing auxiliary support, which controlled the deformation of workpiece material boundary. Experiments were carried out and beryllium bronze was machined with micro end milling tools. The results revealed that burrs were prevented by this method.%在微型零件的微细铣削过程中,微毛刺的产生是影响零件质量的重要因素. 本文提出了一种通过构建辅助支撑抑制微毛刺产生的新方法. 通过分析微毛刺的产生机理,发现微细加工的尺度效应和被加工材料的塑性变形是产生毛刺的主要原因,尤其在被加工材料的边界处毛刺更为明显. 在工件的边界上构建辅助支撑结构可以增强工件边界的刚度,并抑制工件边界处材料的塑性变形. 使用微细刀具进行微细铣削铍青铜的加工试验证明该方法可以抑制微毛刺的生成.

  20. Percutaneous catheter drainage of intrapulmonary fluid collection

    Energy Technology Data Exchange (ETDEWEB)

    Park, E. D.; Kim, H. J.; Choi, P. Y.; Jung, S. H. [Gyeongsang National University Hospital, Chinju (Korea, Republic of)

    1994-01-15

    With the success of percutaneous abdominal abscess drainage, attention is now being focused on the use of similar techniques in the thorax. We studied to evaluate the effect of percutaneous drainage in parenchymal fluid collections in the lungs. We performed percutaneous drainage of abscesses and other parenchymal fluid collections of the lungs in 15 patients. All of the procedures were performed under the fluoroscopic guidance with an 18-gauge Seldinger needle and coaxial technique with a 8-10F drainage catheter. Among 10 patients with lung abscess, 8 patients improved by percutaneous catheter drainage. In one patient, drainage was failed by the accidental withdrawal of the catheter before complete drainage. One patient died of sepsis 5 hours after the procedure. Among three patients with complicated bulla, successful drainage was done in two patients, but in the remaining patient, the procedure was failed. In one patient with intrapulmonary bronchogenic cyst, the drainage was not successful due to the thick internal contents. In one patient with traumatic hematoma, after the drainage of old blood clots, the signs of infection disappeared. Overally, of 14 patients excluding one who died, 11 patients improved with percutaneous catheter drainage and three patients did not. There were no major complications during and after the procedure. We conclude that percutaneous catheter drainage is effective and safe procedure for the treatment of parenchymal fluid collections of the lung in patients unresponsive to the medical treatment.

  1. Technical note on drainage systems

    DEFF Research Database (Denmark)

    Bentzen, Thomas Ruby

    This technical note will present simple but widely used methods for the design of drainage systems. The note will primarily deal with surface water (rainwater) which on a satisfactorily way should be transport into the drainage system. Traditional two types of sewer systems exist: A combined system......’s not major different than described below - just remember to include this contribution for combined systems where the surface water (rain) and sewage are carried in the same pipes in the system and change some of the parameters for failure allowance (this will be elaborated further later on). The technical...... implemented. The document is only to be used in education, since newer (but smaller) changes to some of the statistical parameters are not implemented in this....

  2. EUS-Guided Biliary Drainage

    Directory of Open Access Journals (Sweden)

    Marc Giovannini

    2012-01-01

    Full Text Available The echoendoscopic biliary drainage is an option to treat obstructive jaundices when ERCP drainage fails. These procedures compose alternative methods to the side of surgery and percutaneous transhepatic biliary drainage, and it was only possible by the continuous development and improvement of echoendoscopes and accessories. The development of linear setorial array echoendoscopes in early 1990 brought a new approach to diagnostic and therapeutic dimenion on echoendoscopy capabilities, opening the possibility to perform punction over direct ultrasonographic view. Despite of the high success rate and low morbidity of biliary drainage obtained by ERCP, difficulty could be found at the presence of stent tumor ingrown, tumor gut compression, periampulary diverticula, and anatomic variation. The echoendoscopic technique starts performing punction and contrast of the left biliary tree. When performed from gastric wall, the access is made through hepatic segment III. From duodenum, direct common bile duct punction. Dilatation is required before stent introduction, and a plastic or metallic stent is introduced. This phrase should be replaced by: diathermic dilatation of the puncturing tract is required using a 6F cystostome. The technical success of hepaticogastrostomy is near 98%, and complications are present in 36%: pneumoperitoneum, choleperitoneum, infection, and stent disfunction. To prevent bile leakage, we have used the 2 stent techniques, the first stent introduced was a long uncovered metallic stent (8 or 10 cm, and inside this first stent a second fully covered stent of 6 cm was delivered to bridge the bile duct and the stomach. Choledochoduodenostomy overall success rate is 92% and described complications include, in frequency order, pneumoperitoneum and focal bile peritonitis, present in 19%. By the last 10 years, the technique was especially performed in reference centers, by ERCP experienced groups, and this seems to be a general

  3. Vertical drainage capacity of new electrical drainage board on improvement of super soft clayey ground

    Institute of Scientific and Technical Information of China (English)

    沈扬; 励彦德; 黄文君; 徐海东; 胡品飞

    2015-01-01

    As an advanced polymer composites electro-kinetic geosynthetics, the electro-osmotic vertical drainage (EVD) board could drain water quickly and accelerate consolidation process. However, the drainage rate was mainly impacted by the vertical drainage capability. Therefore, vertical drainage capability at the top of EVD board was theoretically analyzed. Basic requirements for drainage at the top of the board were summed up, as well as the formula of anode pore pressure when losing the vertical drainage capability. Meanwhile, a contrast test on the top and bottom drainage capacities was conducted. In use of the advanced EVD board, the voltage potential and pore pressure of anode were measured. Moreover, the derived formulas were verified. The result shows that the decrease of electric force gradient had an observable impact on the drainage capability. There was nearly no difference between the energy consumption for the two drainage methods. Although a little less water was discharged, the top drainage method had more advantages, such as high initial drainage velocity, few soil cracks, low anode water content and high soil strength. All of these show that the super soft soil ground could be consolidated quickly in use of the advanced EVD board through the top drainage. The top drainage method could efficiently improve the drainage effect, decrease the energy consumption and speed up the project proceeding.

  4. Deburring small intersecting holes

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, L.K.

    1980-08-01

    Deburring intersecting holes is one of the most difficult deburring tasks faced by many industries. Only 14 of the 37 major deburring processes are applicable to most intersecting hole applications. Only five of these are normally applicable to small or miniature holes. Basic process capabilities and techniques used as a function of hole sizes and intersection depths are summarized.

  5. Drainage area data for Alabama streams

    Science.gov (United States)

    Stallings, J.S.; Peirce, L.B.

    1957-01-01

    The drainage area of a river basin is an important parameter in many engineering equations used for hydrologic design. It is not a parameter, however, that always requires precise measurement. Factors in the hydrologic cycle such as rainfall, runoff, transpiration, and infiltration cannot be measured nearly as closely as drainage area. Largely for this reason, drainage areas are often measured to varying degrees of precision depending upon the immediate need, with little thought to some other use or some other user of the figure obtained. It can readily be appreciated that this practice, continued for long by many different agencies, will result in a heterogeneous collection of drainage area figures, often discordant and of an accuracy unknown to any but those who computed them. Figures of drainage area published by various Federal agencies are frequently discrepant or contradictory, giving rise to confusion in the use of drainage area data. Seeking to better this situation, the Federal Inter-Agency River Basin Committee (FIARBC) in November 1951 published its Bulletin No. 4, Inter-Agency Coordination of Drainage Area Data. That Bulletin recommended procedures to be followed by the interested Federal agencies “for coordinating drainage area data in the interest of promoting uniformity, reducing confusion and contradiction of published figures, and improving the ready availability of drainage area data pertaining to drainage basins of the United States and its possessions.”

  6. Life inside black holes

    CERN Document Server

    Dokuchaev, V I

    2012-01-01

    We consider test planet and photon orbits of the third kind inside a black hole, which are stable, periodic and neither come out of the black hole nor terminate at the singularity. Interiors of supermassive black holes may be inhabited by advanced civilizations living on planets with the third-kind orbits. In principle, one can get information from the interiors of black holes by observing their white hole counterparts.

  7. A Stratigraphic, Granulometric, and Textural Comparison of recent pyroclastic density current deposits exposed at West Island and Burr Point, Augustine Volcano, Alaska

    Science.gov (United States)

    Rath, C. A.; Browne, B. L.

    2011-12-01

    Augustine Volcano (Alaska) is the most active volcano in the eastern Aleutian Islands, with 6 violent eruptions over the past 200 years and at least 12 catastrophic debris-avalanche deposits over the past ~2,000 years. The frequency and destructive nature of these eruptions combined with the proximity of Augustine Volcano to commercial ports and populated areas represents a significant hazard to the Cook Inlet region of Alaska. The focus of this study examines the relationship between debris-avalanche events and the subsequent emplacement of pyroclastic density currents by comparing the stratigraphic, granulometric, and petrographic characteristics of pyroclastic deposits emplaced following the 1883 A.D. Burr Point debris-avalanche and those emplaced following the ~370 14C yr B.P. West Island debris-avalanche. Data from this study combines grain size and componentry analysis of pyroclastic deposits with density, textural, and compositional analysis of juvenile clasts contained in the pyroclastic deposits. The 1883 A.D. Burr Point pyroclastic unit immediately overlies the 1883 debris avalanche deposit and underlies the 1912 Katmai ash. It ranges in thickness from 4 to 48 cm and consists of fine to medium sand-sized particles and coarser fragments of andesite. In places, this unit is normally graded and exhibits cross-bedding. Many of these samples are fines-enriched, with sorting coefficients ranging from -0.1 to 1.9 and median grain size ranging from 0.1 to 2.4 mm. The ~370 14C yr B.P. West Island pyroclastic unit is sandwiched between the underlying West Island debris-avalanche deposit and the overlying 1912 Katmai Ash deposit, and at times a fine-grained gray ash originating from the 1883 eruption. West Island pyroclastic deposit is sand to coarse-sand-sized and either normally graded or massive with sorting coefficients ranging from 0.9 to 2.8 and median grain sizes ranging from 0.4 to 2.6 mm. Some samples display a bimodal distribution of grain sizes, while

  8. Mine Drainage Generation and Control Options.

    Science.gov (United States)

    Wei, Xinchao; Rodak, Carolyn M; Zhang, Shicheng; Han, Yuexin; Wolfe, F Andrew

    2016-10-01

    This review provides a snapshot of papers published in 2015 relevant to the topic of mine drainage generation and control options. The review is broken into 3 sections: Generation, Prediction and Prevention, and Treatment Options. The first section, mine drainage generation, focuses on the characterization of mine drainage and the environmental impacts. As such, it is broken into three subsections focused on microbiological characterization, physiochemical characterization, and environmental impacts. The second section of the review is divided into two subsections focused on either the prediction or prevention of acid mine drainage. The final section focuses on treatment options for mine drainage and waste sludge. The third section contains subsections on passive treatment, biological treatment, physiochemical treatment, and a new subsection on beneficial uses for mine drainage and treatment wastes.

  9. Drainage basin delineations for selected USGS streamflow-gaging stations in Virginia (Drainage_Basin)

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The Drainage_Basin polygon feature class was created as a digital representation of drainage basins for more than 1,650 continuous-record streamflow-gaging stations,...

  10. Subsurface drainage volume reduction with drainage water management: Case studies in Ohio, USA

    Science.gov (United States)

    One of the main contributors to poor water quality in the Mississippi River and aeral increase in the hypoxic zone in the Gulf of Mexico is intensive drainage of the cropland within the watershed. Controlled drainage has been demonstrated as an approach to curb totla drainage outflow and nutrient di...

  11. Hole Detection for Quantifying Connectivity in Wireless Sensor Networks: A Survey

    Directory of Open Access Journals (Sweden)

    Pearl Antil

    2014-01-01

    Full Text Available Owing to random deployment, environmental factors, dynamic topology, and external attacks, emergence of holes in wireless sensor networks is inescapable. Hole is an area in sensor network around which sensors cease to sense or communicate due to drainage of battery or any fault, either temporary or permanent. Holes impair sensing and communication functions of network; thus their identification is a major concern. This paper discusses different types of holes and significance of hole detection in wireless sensor networks. Coverage hole detection schemes have been classified into three categories based on the type of information used by algorithms, computation model, and network dynamics for better understanding. Then, relative strengths and shortcomings of some of the existing coverage hole detection algorithms are discussed. The paper is concluded by highlighting various future research directions.

  12. 24 CFR 3285.604 - Drainage system.

    Science.gov (United States)

    2010-04-01

    ... § 3285.604 Drainage system. (a) Crossovers. Multi-section homes with plumbing in more than one section require drainage system crossover connections to join all sections of the home. The crossover design requirements are located in, and must be designed in accordance with, § 3280.610 of this chapter. (b)...

  13. Agricultural drainage: Towards an integrated approach

    NARCIS (Netherlands)

    Abdeldayem, S.; Hoevenaars, J.; Mollinga, P.P.; Scheuman, W.; Slootweg, R.; Steenbergen, van F.

    2005-01-01

    Drainage needs to reclaim its rightful position as an indispensable element in the integrated management of land and water. An integrated approach to drainage can be developed by means of systematic mapping of the functions of natural resources systems (goods and services) and the values attributed

  14. Black hole hair removal

    Science.gov (United States)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-07-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair — degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  15. Black Hole Hair Removal

    CERN Document Server

    Banerjee, Nabamita; Sen, Ashoke

    2009-01-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair, -- degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  16. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

    2007-11-15

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

  17. Black Hole Thermodynamics

    Science.gov (United States)

    Israel, Werner

    This chapter reviews the conceptual developments on black hole thermodynamics and the attempts to determine the origin of black hole entropy in terms of their horizon area. The brick wall model and an operational approach are discussed. An attempt to understand at the microlevel how the quantum black hole acquires its thermal properties is included. The chapter concludes with some remarks on the extension of these techniques to describing the dynamical process of black hole evaporation.

  18. Monopole black hole skyrmions

    OpenAIRE

    Moss, I. G.; Shiiki, N.; Winstanley, E.

    2000-01-01

    Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.

  19. Ballistic hole magnetic microscopy

    NARCIS (Netherlands)

    Haq, E.; Banerjee, T.; Siekman, M.H.; Lodder, J.C.; Jansen, R.

    2005-01-01

    A technique to study nanoscale spin transport of holes is presented: ballistic hole magnetic microscopy. The tip of a scanning tunneling microscope is used to inject hot electrons into a ferromagnetic heterostructure, where inelastic decay creates a distribution of electron-hole pairs. Spin-dependen

  20. Endoscopic ultrasound-guided drainage of pancreatic pseudocysts

    DEFF Research Database (Denmark)

    Saftoiu, Adrian; Vilmann, Andreas; Vilmann, Peter

    2015-01-01

    Pancreatic pseudocysts are fluid collections in the peripancreatic tissues associated with acute or chronic pancreatitis. Endoscopic ultrasound (EUS)-guided drainage has become an established indication, having better results as compared to percutaneous drainage, nonguided endoscopic drainage...

  1. Sound Hole Sound

    CERN Document Server

    Politzer, David

    2015-01-01

    The volume of air that goes in and out of a musical instrument's sound hole is related to the sound hole's contribution to the volume of the sound. Helmholtz's result for the simplest case of steady flow through an elliptical hole is reviewed. Measurements on multiple holes in sound box geometries and scales relevant to real musical instruments demonstrate the importance of a variety of effects. Electric capacitance of single flat plates is a mathematically identical problem, offering an alternate way to understand the most important of those effects. The measurements also confirm and illuminate aspects of Helmholtz's "bottle" resonator model as applied to musical instrument sound boxes and sound holes.

  2. Black holes in binary stars

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1996-01-01

    Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

  3. The Geochemistry of Acid Mine Drainage

    Science.gov (United States)

    Blowes, D. W.; Ptacek, C. J.; Jambor, J. L.; Weisener, C. G.

    2003-12-01

    Mine wastes are the largest volume of materials handled in the world (ICOLD, 1996). The generation of acidic drainage and the release of water containing high concentrations of dissolved metals from these wastes is an environmental problem of international scale. Acidic drainage is caused by the oxidation of sulfide minerals exposed to atmospheric oxygen. Although acid drainage is commonly associated with the extraction and processing of sulfide-bearing metalliferous ore deposits and sulfide-rich coal, acidic drainage can occur wherever sulfide minerals are excavated and exposed to atmospheric oxygen. Engineering projects, including road construction, airport development, and foundation excavation are examples of civil projects that have resulted in the generation of acidic drainage. On United States Forest Service Lands there are (2-5)×104 mines releasing acidic drainage (USDA, 1993). Kleinmann et al. (1991) estimated that more than 6,400 km of rivers and streams in the eastern United States have been adversely affected by mine-drainage water. About (0.8-1.6)×104 km of streams have been affected by metal mining in the western United States. The annual worldwide production of mine wastes exceeded 4.5 Gt in 1982 (ICOLD, 1996). Estimated costs for remediating mine wastes internationally total in the tens of billions of dollars ( Feasby et al.,1991).

  4. On Accelerated Black Holes

    CERN Document Server

    Letelier, P S; Letelier, Patricio S.; Oliveira, Samuel R.

    1998-01-01

    The C-metric is revisited and global interpretation of some associated spacetimes are studied in some detail. Specially those with two event horizons, one for the black hole and another for the acceleration. We found that the spacetime fo an accelerated Schwarzschild black hole is plagued by either conical singularities or lack of smoothness and compactness of the black hole horizon. By using standard black hole thermodynamics we show that accelerated black holes have higher Hawking temperature than Unruh temperature. We also show that the usual upper bound on the product of the mass and acceleration parameters (<1/sqrt(27)) is just a coordinate artifact. The main results are extended to accelerated Kerr black holes. We found that they are not changed by the black hole rotation.

  5. Gravity Drainage Kinetics of Papermaking Fibrous Suspensions

    Directory of Open Access Journals (Sweden)

    Przybysz Piotr

    2014-12-01

    Full Text Available The study analyses application possibilities of filtration and thickening models in evaluation of papermaking suspension drainage rate. The authors proposed their own method to estimate the drainage rate on the basis of an existing Ergun capillary model of liquid flow through a granular material. The proposed model was less sensitive to porosity changes than the Ergun model. An empirical verification proved robustness of the proposed approach. Taking into account discrepancies in the published data concerning how the drainage velocity of papermaking suspension is defined, this study examines which of the commonly applied models matches experimental results the best.

  6. Drainage filter technologies to mitigate site-specific phosphorus losses in agricultural drainage discharge

    DEFF Research Database (Denmark)

    Kjærgaard, Charlotte; Heckrath, Goswin Johann; Canga, Eriona;

    Losses of phosphorus (P) in drainage waters contribute an estimated 33% to the total agricultural P load in Denmark. Mitigating agricultural P losses is challenging, as critical P losses comprise only a very small fraction of actual soil P contents and are not directly related to fertilizer P input...... in drainage. The Danish “SUPREME-TECH” project (2010-2016) (www.supreme-tech.dk) aims at providing the scientific basis for developing cost-effective filter technologies for P in agricultural drainage waters. The project studies different approaches of implementing filter technologies including drainage well...... the occurrence of surface-induced precipitation processes. The P-retention efficiency of granular drainage filters and constructed wetlands was compared for treating drainage water, and a subcatchment analysis illustrated the potential of implementing such measures....

  7. Fractal Analysis of Drainage Basins on Mars

    Science.gov (United States)

    Stepinski, T. F.; Marinova, M. M.; McGovern, P. J.; Clifford, S. M.

    2002-01-01

    We used statistical properties of drainage networks on Mars as a measure of martian landscape morphology and an indicator of landscape evolution processes. We utilize the Mars Orbiter Laser Altimeter (MOLA) data to construct digital elevation maps (DEMs) of several, mostly ancient, martian terrains. Drainage basins and channel networks are computationally extracted from DEMs and their structures are analyzed and compared to drainage networks extracted from terrestrial and lunar DEMs. We show that martian networks are self-affine statistical fractals with planar properties similar to terrestrial networks, but vertical properties similar to lunar networks. The uniformity of martian drainage density is between those for terrestrial and lunar landscapes. Our results are consistent with the roughening of ancient martian terrains by combination of rainfall-fed erosion and impacts, although roughening by other fluvial processes cannot be excluded. The notion of sustained rainfall in recent Mars history is inconsistent with our findings.

  8. Results of percutaneous transhepatic cholangiography drainages (PTCD)

    Energy Technology Data Exchange (ETDEWEB)

    Schoenemann, J.; Willems, M.; Wolf, G.; Fromme, M.

    1987-12-01

    From September 1980 to December 1986, 72 percutaneous transhepatic cholangiography drainages (PTCD) were performed in 64 patients (58 palliative in malignant obstructions, 14 temporary). The median duration of drainage was 26.8 days (2-183 days). The median survival time in 37 patients with palliative tumour drainage was 55.3 days (7-473 days). 9/37 patients survived longer than 3 months (max. 15.5 months). Complications occurred in 29.5% (10.3% severe). 3/64 patients (4.7%) died. Patients with palliative transpapillary drainages (23), especially with endoprostheses (14), survived longer, and the complication rate was lower. Therefore, we prefer the endoscopic transpapillary approach. PTCD patients must be selected carefully.

  9. Percutaneous drainage of pelvic fluid collection

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Young; Sohn, Cheol Ho [School of Medicine Keimyung University, Daegu (Korea, Republic of)

    1995-10-15

    To evaluate safe access route and success rate of percutaneous drainage of pelvic fluid collection. The 35 percutaneous drainages of pelvic fluid collection under the CT and fluorosocpic guidance were done in 32 patients. The anterior transabdominal approach was done in 20 patients, while the nine patients used the transgluteal approach through greater sciatic foramen. Three patients, who had septated or noncommunicating abscesses, underwent drainage using both approaches. The catheter was removed when the patient's symptom and laboratory data were improved or the amount of drainage and the size of fluid collection were markedly reduced. Success, partial success and failure were classified. The causes of fluid collection were complication of intraabdominal operation in 27 patient. The diagnosis after drainage included abscess (21), loculated ascites (6), and hematoma (4). The 27 cases (30 procedure) were treated successfully and the mean duration of catheter insertion was 10 days. The partial successes were two cases (2 procedures), which had palliative purpose. Three cases (3 procedures) were failed, which were multiple loculated ascites of pancreatic origin (2) and recurrent abscess (1). The significant complication during the procedure or drainage was not noted.

  10. Extremal Hairy Black Holes

    CERN Document Server

    Gonzalez, P A; Saavedra, Joel; Vasquez, Yerko

    2014-01-01

    We consider a gravitating system consisting of a scalar field minimally coupled to gravity with a self-interacting potential and an U(1) electromagnetic field. Solving the coupled Einstein-Maxwell-scalar system we find exact hairy charged black hole solutions with the scalar field regular everywhere. We go to the zero temperature limit and we study the effect of the scalar field on the near horizon geometry of an extremal black hole. We find that except a critical value of the charge of the black hole there is also a critical value of the charge of the scalar field beyond of which the extremal black hole is destabilized. We study the thermodynamics of these solutions and we find that if the space is flat then at low temperature the Reissner-Nordstr\\"om black hole is thermodynamically preferred, while if the space is AdS the hairy charged black hole is thermodynamically preferred at low temperature.

  11. Astrophysical black holes

    CERN Document Server

    Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

    2016-01-01

    Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

  12. Perturbations around black holes

    CERN Document Server

    Wang, B

    2005-01-01

    Perturbations around black holes have been an intriguing topic in the last few decades. They are particularly important today, since they relate to the gravitational wave observations which may provide the unique fingerprint of black holes' existence. Besides the astrophysical interest, theoretically perturbations around black holes can be used as testing grounds to examine the proposed AdS/CFT and dS/CFT correspondence.

  13. Charged Lifshitz Black Holes

    OpenAIRE

    Dehghani, M. H.; Pourhasan, R.; Mann, R. B.

    2011-01-01

    We investigate modifications of the Lifshitz black hole solutions due to the presence of Maxwell charge in higher dimensions for arbitrary $z$ and any topology. We find that the behaviour of large black holes is insensitive to the topology of the solutions, whereas for small black holes significant differences emerge. We generalize a relation previously obtained for neutral Lifshitz black branes, and study more generally the thermodynamic relationship between energy, entropy, and chemical pot...

  14. Asymptotic Black Holes

    CERN Document Server

    Ho, Pei-Ming

    2016-01-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  15. Asymptotic black holes

    Science.gov (United States)

    Ho, Pei-Ming

    2017-04-01

    Following earlier works on the KMY model of black-hole formation and evaporation, we construct the metric for a matter sphere in gravitational collapse, with the back-reaction of pre-Hawking radiation taken into consideration. The mass distribution and collapsing velocity of the matter sphere are allowed to have an arbitrary radial dependence. We find that a generic gravitational collapse asymptote to a universal configuration which resembles a black hole but without horizon. This approach clarifies several misunderstandings about black-hole formation and evaporation, and provides a new model for black-hole-like objects in the universe.

  16. 30 CFR 816.15 - Casing and sealing of drilled holes: Permanent.

    Science.gov (United States)

    2010-07-01

    .... 816.15 Section 816.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT...-SURFACE MINING ACTIVITIES § 816.15 Casing and sealing of drilled holes: Permanent. When no longer needed... other toxic drainage from entering ground or surface waters....

  17. Variation in gas drainage rate from a coal seam during mining

    Institute of Scientific and Technical Information of China (English)

    Li; Gang; Qi; Qingxin; Li; Hongyan; Fan; Xisheng

    2012-01-01

    Gas flow patterns during draining of gas from a coal seam during mining are discussed.The coal seam is treated as a dual medium with both pores and cracks.The seepage,diffusion,and desorption processes are treated using a gas flow equation that describes flow around drill holes.MATLAB is used to solve the differential equations.The permeability tracer test results from a mined coal seam are used to study the variation in gas drainage from a coal seam during mining.The results show that mining can increase the permeability of a coal seam,which then increases the gas drainage.There are inflection points in this variation over time.A close relationship between this variation and the rate of change in coal seam permeability is observed.

  18. Location of Agricultural Drainage Pipes and Assessment of Agricultural Drainage Pipe Conditions Using Ground Penetrating Radar

    Science.gov (United States)

    Methods are needed to not only locate buried agricultural drainage pipe, but to also determine if the pipes are functioning properly with respect to water delivery. The primary focus of this research project was to confirm the ability of ground penetrating radar (GPR) to locate buried drainage pipe ...

  19. Newborn Black Holes

    Science.gov (United States)

    Science Teacher, 2005

    2005-01-01

    Scientists using NASA's Swift satellite say they have found newborn black holes, just seconds old, in a confused state of existence. The holes are consuming material falling into them while somehow propelling other material away at great speeds. "First comes a blast of gamma rays followed by intense pulses of x-rays. The energies involved are much…

  20. Perturbing supersymmetric black hole

    CERN Document Server

    Onozawa, H; Mishima, T; Ishihara, H; Onozawa, Hisashi; Okamura, Takashi; Mishima, Takashi; Ishihara, Hideki

    1996-01-01

    An investigation of the perturbations of the Reissner-Nordstr\\"{o}m black hole in the N=2 supergravity is presented. In the extreme case, the black hole responds to the perturbation of each field in the same manner. This is possibly because we can match the modes of the graviton, gravitino, and photon using supersymmetry transformations.

  1. Black Hole Dynamic Potentials

    Indian Academy of Sciences (India)

    Koustubh Ajit Kabe

    2012-09-01

    In the following paper, certain black hole dynamic potentials have been developed definitively on the lines of classical thermodynamics. These potentials have been refined in view of the small differences in the equations of the laws of black hole dynamics as given by Bekenstein and those of thermodynamics. Nine fundamental black hole dynamical relations have been developed akin to the four fundamental thermodynamic relations of Maxwell. The specific heats , and , have been defined. For a black hole, these quantities are negative. The d equation has been obtained as an application of these fundamental relations. Time reversible processes observing constancy of surface gravity are considered and an equation connecting the internal energy of the black hole , the additional available energy defined as the first free energy function , and the surface gravity , has been obtained. Finally as a further application of the fundamental relations, it has been proved for a homogeneous gravitational field in black hole space times or a de Sitter black hole that $C_{\\Omega,\\Phi}-C_{J,Q}=\\kappa \\left[\\left(\\dfrac{\\partial J}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial \\Omega}{\\partial \\kappa}\\right)_{J,Q}+\\left(\\dfrac{\\partial Q}{\\partial \\kappa}\\right)_{\\Omega,\\Phi}\\left(\\dfrac{\\partial\\Phi}{\\partial \\kappa}\\right)_{J,Q}\\right]$. This is dubbed as the homogeneous fluid approximation in context of the black holes.

  2. Black holes matter

    DEFF Research Database (Denmark)

    Kragh, Helge Stjernholm

    2016-01-01

    Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015).......Review essay, Marcia Bartusiak, Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved (New Haven: Yale University Press, 2015)....

  3. Scattering by Black Holes

    CERN Document Server

    Andersson, N

    2000-01-01

    This is a chapter on Black-hole Scattering that was commissioned for an Encyclopaedia on Scattering edited by Pike and Sabatier, to be published by Academic Press. The chapter surveys wave propagation in black-hole spacetimes, diffraction effects in wave scattering, resonances, quasinormal modes and related topics.

  4. Disregarding the 'Hole Argument'

    CERN Document Server

    Roberts, Bryan W

    2014-01-01

    Jim Weatherall has suggested that Einstein's hole argument, as presented by Earman and Norton (1987), is based on a misleading use of mathematics. I argue on the contrary that Weatherall demands an implausible restriction on how mathematics is used. The hole argument, on the other hand, is in no new danger at all.

  5. Regional gas drainage techniques in Chinese coal mines

    Institute of Scientific and Technical Information of China (English)

    Wang Haifeng; Cheng Yuanping; Wang Lei

    2012-01-01

    China's rapid economic development has increased the demand for coal.These results in Chinese coal mines being extended to deeper levels.The eastern Chinese,more economical developed,regions have a long history of coal mining and many coal mines have now started deep mining at a depth from 800 to 1500 m.This increase in mining depth,geostresses,pressures,and gas content of the coal seam complicates geologic construction conditions.Lower permeability and softer coal contribute to increasing numbers of coal and gas outburst,and gas explosion,disasters.A search on effective methods of preventing gas disasters has been provided funds from the Chinese government since 1998.The National Engineering Research Center of Coal Gas Control and the Huainan and Huaibei Mining Group have conducted theoretical and experimental research on a regional gas extraction technology.The results included two important findings.First,grouped coal seams allow adoption of a method where a first,key protective layer is mined to protect upper and lower coal seams by increasing permeability from 400 to 3000 times.Desorption of gas and gas extraction in the protected coal seam of up to 60%,or more,may be achieved in this way.Second,a single seam may be protected by using a dense network of extraction boreholes consisting of cross and along-bed holes.Combined with this is increased use of water that increases extraction of coal seam gas by up to 50%.Engineering practice showed that regional gas drainage technology eliminates regional coal and gas outburst and also enables mining under low gas conditions.These research results have been adopted into the national safety codes of production technology.This paper systematically introduces the principles of the technology,the engineering methods and techniques,and the parameters of regional gas drainage.Engineering applications are discussed.

  6. Regional gas drainage techniques in Chinese coal mines

    Institute of Scientific and Technical Information of China (English)

    Wang; Haifeng; Cheng; Yuanping; Wang; Lei

    2012-01-01

    China's rapid economic development has increased the demand for coal.These results in Chinese coal mines being extended to deeper levels.The eastern Chinese,more economical developed,regions have a long history of coal mining and many coal mines have now started deep mining at a depth from 800 to 1500 m.This increase in mining depth,geostresses,pressures,and gas content of the coal seam complicates geologic construction conditions.Lower permeability and softer coal contribute to increasing numbers of coal and gas outburst,and gas explosion,disasters.A search on effective methods of preventing gas disasters has been provided funds from the Chinese government since 1998.The National Engineering Research Center of Coal Gas Control and the Huainan and Huaibei Mining Group have conducted theoretical and experimental research on a regional gas extraction technology.The results included two important findings.First,grouped coal seams allow adoption of a method where a first,key protective layer is mined to protect upper and lower coal seams by increasing permeability from 400 to 3000 times.Desorption of gas and gas extraction in the protected coal seam of up to 60%,or more,may be achieved in this way.Second,a single seam may be protected by using a dense network of extraction boreholes consisting of cross and along-bed holes.Combined with this is increased use of water that increases extraction of coal seam gas by up to 50%.Engineering practice showed that regional gas drainage technology eliminates regional coal and gas outburst and also enables mining under low gas conditions.These research results have been adopted into the national safety codes of production technology.This paper systematically introduces the principles of the technology,the engineering methods and techniques,and the parameters of regional gas drainage.Engineering applications are discussed.

  7. Cosmological Black Holes

    CERN Document Server

    Stornaiolo, C

    2002-01-01

    In this letter we propose the existence of low density black holes and discuss its compatibility with the cosmological observations. The origin of these black holes can be traced back to the collapse of long wavelength cosmological perturbations during the matter dominated era, when the densities are low enough to neglect any internal and thermal pressure. By introducing a threshold density $\\hat{\\rho}$ above which pressure and non-gravitational interactions become effective, we find the highest wavelength for the perturbations that can reach an equilibrium state instead of collapsing to a black hole. The low density black holes introduced here, if they exist, can be observed through weak and strong gravitational lensing effects. Finally we observe that we obtained here a cosmological model which is capable to explain in a qualitative way the void formation together with the value $\\Omega=1$. But we remark that it needs to be improved by considering non spherical symmetric black holes.

  8. Primordial Black Hole Baryogenesis

    CERN Document Server

    Baumann, D; Turok, N G; Baumann, Daniel; Steinhardt, Paul J.; Turok, Neil

    2007-01-01

    We reconsider the possibility that the observed baryon asymmetry was generated by the evaporation of primordial black holes that dominated the early universe. We present a simple derivation showing that the baryon asymmetry is insensitive to the initial black hole density and the cosmological model but is sensitive to the temperature-dependence of the CP and baryon-violating (or lepton-violating) interactions. We also consider the possibility that black holes stop evaporating and form Planck-mass remnants that act as dark matter. We show that primordial black holes cannot simultaneously account for both the observed baryon asymmetry and the (remnant) dark matter density unless the magnitude of CP violation is much greater than expected from most particle physics models. Finally, we apply these results to ekpyrotic/cyclic models, in which primordial black holes may form when branes collide. We find that obtaining the observed baryon asymmetry is compatible with the other known constraints on parameters.

  9. Lifshitz Topological Black Holes

    CERN Document Server

    Mann, R B

    2009-01-01

    I find a class of black hole solutions to a (3+1) dimensional theory gravity coupled to abelian gauge fields with negative cosmological constant that has been proposed as the dual theory to a Lifshitz theory describing critical phenomena in (2+1) dimensions. These black holes are all asymptotic to a Lifshitz fixed point geometry and depend on a single parameter that determines both their area (or size) and their charge. Most of the solutions are obtained numerically, but an exact solution is also obtained for a particular value of this parameter. The thermodynamic behaviour of large black holes is almost the same regardless of genus, but differs considerably for small black holes. Screening behaviour is exhibited in the dual theory for any genus, but the critical length at which it sets in is genus-dependent for small black holes.

  10. Urban Drainage Modeling and Flood Risk Management

    Science.gov (United States)

    Schmitt, Theo G.; Thomas, Martin

    The European research project in the EUREKA framework, RisUrSim (Σ!2255) has been worked out by a project consortium including industrial mathematics and water engineering research institutes, municipal drainage works as well as an insurance company. The overall objective has been the development of a simulation to allow flood risk analysis and cost-effective management for urban drainage systems. In view of the regulatory background of European Standard EN 752, the phenomenon of urban flooding caused by surcharged sewer systems in urban drainage systems is analyzed, leading to the necessity of dual drainage modeling. A detailed dual drainage simulation model is described based upon hydraulic flow routing procedures for surface flow and pipe flow. Special consideration is given to the interaction between surface and sewer flow in order to most accurately compute water levels above ground as a basis for further assessment of possible damage costs. The model application is presented for small case study in terms of data needs, model verification, and first simulation results.

  11. Black Hole Critical Phenomena Without Black Holes

    CERN Document Server

    Liebling, S L

    2000-01-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  12. The On-Line Detection System of Disposable Syringe Needle Point Burrs%一次性注射器针尖毛刺在线检测系统

    Institute of Scientific and Technical Information of China (English)

    邰兆海

    2012-01-01

    针对国内注射器生产企业依靠人工目视或手工触摸检测注射器针尖毛刺易发生视觉疲劳、手被划伤和漏检等问题,采用机器视觉技术以及PLC与触摸屏,设计开发了一次性注射器针尖毛刺在线检测系统.实践证明,该系统检测速度快、精度高,具有很好的应用价值.%The domestic syringe production enterprises detect syringe needle point burrs by visual check and hand touch which causes problems such as visual fatigue, scratching hand, and missing detection. To solve these problems, an on-line detection system of disposable syringe needle point burrs has been designed and developed through machine visual technology, PLC and touch screen. It has been proved that this system has extremely high application value for its high speed and accurateness.

  13. Black holes new horizons

    CERN Document Server

    Hayward, Sean Alan

    2013-01-01

    Black holes, once just fascinating theoretical predictions of how gravity warps space-time according to Einstein's theory, are now generally accepted as astrophysical realities, formed by post-supernova collapse, or as supermassive black holes mysteriously found at the cores of most galaxies, powering active galactic nuclei, the most powerful objects in the universe. Theoretical understanding has progressed in recent decades with a wider realization that local concepts should characterize black holes, rather than the global concepts found in textbooks. In particular, notions such as trapping h

  14. Scalarized hairy black holes

    Energy Technology Data Exchange (ETDEWEB)

    Kleihaus, Burkhard, E-mail: b.kleihaus@uni-oldenburg.de [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Kunz, Jutta [Institut für Physik, Universität Oldenburg, Postfach 2503, D-26111 Oldenburg (Germany); Yazadjiev, Stoytcho [Department of Theoretical Physics, Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria)

    2015-05-11

    In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  15. Scalarized hairy black holes

    Directory of Open Access Journals (Sweden)

    Burkhard Kleihaus

    2015-05-01

    Full Text Available In the presence of a complex scalar field scalar–tensor theory allows for scalarized rotating hairy black holes. We exhibit the domain of existence for these scalarized black holes, which is bounded by scalarized rotating boson stars and hairy black holes of General Relativity. We discuss the global properties of these solutions. Like their counterparts in general relativity, their angular momentum may exceed the Kerr bound, and their ergosurfaces may consist of a sphere and a ring, i.e., form an ergo-Saturn.

  16. Black Hole Entropy

    OpenAIRE

    P. Mitra

    1994-01-01

    In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy $S^{BH}$ (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy $S^{SM}=-\\mbox{Tr}(\\hat{\\rho}\\ln \\hat{\\rho})$ (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (...

  17. Black hole entropy

    CERN Document Server

    Frolov, V

    1994-01-01

    In the talk different definitions of the black hole entropy are discussed and compared. It is shown that the Bekenstein-Hawking entropy S^{BH} (defined by the response of the free energy of a system containing a black hole on the change of the temperature) differs from the statistical- mechanical entropy S^{SM}=-\\mbox{Tr}(\\hat{\\rho}\\ln \\hat{\\rho}) (defined by counting internal degrees of freedom of a black hole). A simple explanation of the universality of the Bekenstein-Hawking entropy (i.e. its independence of the number and properties of the fields which might contribute to S^{SM}) is given.

  18. Primordial Black Holes

    CERN Document Server

    MacGibbon, Jane H; Linnemann, J T; Marinelli, S S; Stump, D; Tollefson, K

    2015-01-01

    Primordial Black Holes (PBHs) are of interest in many cosmological contexts. PBHs lighter than about 1012 kg are predicted to be directly detectable by their Hawking radiation. This radiation should produce both a diffuse extragalactic gamma-ray background from the cosmologically-averaged distribution of PBHs and gamma-ray burst signals from individual light black holes. The Fermi, Milagro, Veritas, HESS and HAWC observatories, in combination with new burst recognition methodologies, offer the greatest sensitivity for the detection of such black holes or placing limits on their existence.

  19. Black Hole Thermodynamics

    CERN Document Server

    Carlip, S

    2014-01-01

    The discovery in the early 1970s that black holes radiate as black bodies has radically affected our understanding of general relativity, and offered us some early hints about the nature of quantum gravity. In this chapter I will review the discovery of black hole thermodynamics and summarize the many independent ways of obtaining the thermodynamic and (perhaps) statistical mechanical properties of black holes. I will then describe some of the remaining puzzles, including the nature of the quantum microstates, the problem of universality, and the information loss paradox.

  20. Gas drainage technology of high gas and thick coal seam

    Institute of Scientific and Technical Information of China (English)

    HE Tian-cai; LI Hai-gui; ZHANG Hai-jun

    2009-01-01

    Gas drainage in Jincheng Mining Group Co., Ltd. was introduced briefly and the importance of gas drainage in gas control was analyzed. Combined with coal-bed gas oc-currence and gas emission, the double system of gas drainage was optimized and a pro-gressive gas drainage model was experimented on. For guaranteed drainage, excavation and mining and realization of safety production and reasonable exploitation of gas in coal seams, many drainage methods were adopted to solve the gas problem of the working face.

  1. Black hole critical phenomena without black holes

    Indian Academy of Sciences (India)

    Steven L Liebling

    2000-10-01

    Studying the threshold of black hole formation via numerical evolution has led to the discovery of fascinating nonlinear phenomena. Power-law mass scaling, aspects of universality, and self-similarity have now been found for a large variety of models. However, questions remain. Here I briefly review critical phenomena, discuss some recent results, and describe a model which demonstrates similar phenomena without gravity.

  2. Drainage hydraulics of permeable friction courses

    Science.gov (United States)

    Charbeneau, Randall J.; Barrett, Michael E.

    2008-04-01

    This paper describes solutions to the hydraulic equations that govern flow in permeable friction courses (PFC). PFC is a layer of porous asphalt approximately 50 mm thick that is placed as an overlay on top of an existing conventional concrete or asphalt road surface to help control splash and hydroplaning, reduce noise, and enhance quality of storm water runoff. The primary objective of this manuscript is to present an analytical system of equations that can be used in design and analysis of PFC systems. The primary assumptions used in this analysis are that the flow can be modeled as one-dimensional, steady state Darcy-type flow and that slopes are sufficiently small so that the Dupuit-Forchheimer assumptions apply. Solutions are derived for cases where storm water drainage is confined to the PFC bed and for conditions where the PFC drainage capacity is exceeded and ponded sheet flow occurs across the pavement surface. The mathematical solutions provide the drainage characteristics (depth and residence time) as a function of rainfall intensity, PFC hydraulic conductivity, pavement slope, and maximum drainage path length.

  3. Selecting the drainage method for agricultural land

    NARCIS (Netherlands)

    Bos, M.G.

    2001-01-01

    To facilitate crop growth excess water should be drained from the rooting zone to allow root development of the crop and from the soil surface to facilitate access to the field. Basically, there are three drainage methods from which the designer can select being; surface drains, pumped tube wells an

  4. [Artificial drainage devices--history, indications].

    Science.gov (United States)

    Barac, Ileana Ramona; Pop, Monica

    2012-01-01

    Glaucoma is a degenerative optic neuropathy progressive, multifactorial, which can lead to blindness. Blindness in patients with glaucoma is defined as visual field reduction below 10 degrees. Artificial drainage systems are a solution for refractory to medication, laser treatment or conventional surgery. Used by over 100 years, improved with good surgical technique and careful patient follow-up surgery, postoperative results are satisfactory.

  5. Impact of land drainage on peatland hydrology.

    Science.gov (United States)

    Holden, J; Evans, M G; Burt, T P; Horton, M

    2006-01-01

    There is a long history of drainage of blanket peat but few studies of the long-term hydrological impact of drainage. This paper aims to test differences in runoff production processes between intact and drained blanket peat catchments and determine whether there have been any long-term changes in stream flow since drainage occurred. Hillslope runoff processes and stream discharge were measured in four blanket peat catchments. Two catchments were drained with open-cut ditches in the 1950s. Ditching originally resulted in shorter lag times and flashier storm hydrographs but no change in the annual catchment runoff efficiency. In the period between 2002 and 2004, the hydrographs in the drained catchments, while still flashy, were less sensitive to rainfall than in the 1950s and the runoff efficiency had significantly increased. Drains resulted in a distinctive spatial pattern of runoff production across the slopes. Overland flow was significantly lower in the drained catchments where throughflow was more dominant. In the intact peatlands, matrix throughflow produced by peat layers below 10 cm was rare and produced structure could explain the long-term changes in river flow, which are in addition to those occurring in the immediate aftermath of peatland drainage.

  6. Reality named endoscopic ultrasound biliary drainage

    Institute of Scientific and Technical Information of China (English)

    Hugo; Gon?alo; Guedes; Roberto; Iglesias; Lopes; Joel; Fernandez; de; Oliveira; Everson; Luiz; de; Almeida; Artifon

    2015-01-01

    Endoscopic ultrasound(EUS) is used for diagnosis and evaluation of many diseases of the gastrointestinal (GI) tract. In the past, it was used to guide a cholangio-graphy, but nowadays it emerges as a powerful thera-peutic tool in biliary drainage. The aims of this review are: outline the rationale for endoscopic ultrasound-guided biliary drainage(EGBD); detail the procedural technique; evaluate the clinical outcomes and limitations of the method; and provide recommendations for the practicing clinician. In cases of failed endoscopic retro-grade cholangiopancreatography(ERCP), patients are usually referred for either percutaneous transhepatic biliary drainage(PTBD) or surgical bypass. Both these procedures have high rates of undesirable complications. EGBD is an attractive alternative to PTBD or surgery when ERCP fails. EGBD can be performed at two locations: transhepatic or extrahepatic, and the stent can be inserted in an antegrade or retrograde fashion. The drainage route can be transluminal, duodenal or trans-papillary, which, again, can be antegrade or retrograde [rendezvous(EUS-RV)]. Complications of all techniques combined include pneumoperitoneum, bleeding, bile leak/peritonitis and cholangitis. We recommend EGBD when bile duct access is not possible because of failed cannulation, altered upper GI tract anatomy, gastric outlet obstruction, a distorted ampulla or a periampullary diverticulum, as a minimally invasive alternative to surgery or radiology.

  7. Interventional radiology in the lacrimal drainage system

    Energy Technology Data Exchange (ETDEWEB)

    Ilgit, Erhan T. [Department of Radiology, School of Medicine, Gazi University, Besevler 06510, Ankara (Turkey)]. E-mail: erhanti@gazi.edu.tr; Oenal, Baran [Department of Radiology, School of Medicine, Gazi University, Besevler 06510, Ankara (Turkey); Coskun, Bilgen [Department of Radiology, School of Medicine, Gazi University, Besevler 06510, Ankara (Turkey)

    2005-09-01

    This article presents a review of the interventional radiological procedures in the lacrimal drainage system. Balloon dacryocystoplasty and nasolacrimal polyurethane stent placement are the main fluoroscopically guided interventions for the treatment of epiphora by recanalizing the obstructed LDS. These procedures can also be used for dacryolith removal and lacrimal sac abscess treatment.

  8. Modelling quantum black hole

    CERN Document Server

    Govindarajan, T R

    2016-01-01

    Novel bound states are obtained for manifolds with singular potentials. These singular potentials require proper boundary conditions across boundaries. The number of bound states match nicely with what we would expect for black holes. Also they serve to model membrane mechanism for the black hole horizons in simpler contexts. The singular potentials can also mimic expanding boundaries elegantly, there by obtaining appropriately tuned radiation rates.

  9. Helical superconducting black holes.

    Science.gov (United States)

    Donos, Aristomenis; Gauntlett, Jerome P

    2012-05-25

    We construct novel static, asymptotically five-dimensional anti-de Sitter black hole solutions with Bianchi type-VII(0) symmetry that are holographically dual to superconducting phases in four spacetime dimensions with a helical p-wave order. We calculate the precise temperature dependence of the pitch of the helical order. At zero temperature the black holes have a vanishing entropy and approach domain wall solutions that reveal homogenous, nonisotropic dual ground states with an emergent scaling symmetry.

  10. Holes in Heisenberg antiferromagnets

    Science.gov (United States)

    Chen, Yang

    1990-05-01

    In this Brief Report we show that a recent model proposed by Shankar [Phys. Rev. Lett. 63, 203 (1989)], describing the motion of holes in quantum antiferromagnets is equivalent to the Schwinger model [Phys. Rev. 128, 2425 (1962)] in 1+1 dimensions. Some exact results are deduced. In addition to the superconducting long-range order found by Shankar, it is shown that there is a 2pF hole density wave existing with the superconducting pairing instability.

  11. Life Inside Black Holes

    Science.gov (United States)

    Dokuchaev, Vyacheslav

    2013-11-01

    It is considered the test planet and photon orbits of the third kind inside the black hole (BH), which are stable, periodic and neither come out the BH nor terminate at the central singularity. Interiors of the supermassive BHs may be inhabited by advanced civilizations living on the planets with the third kind orbits. In principle, one can get information from the interiors of BHs by observing their white hole counterparts.

  12. Braneworld black holes

    CERN Document Server

    Gregory, Ruth

    2008-01-01

    In these lectures, I give an introduction to and overview of braneworlds and black holes in the context of warped compactifications. I first describe the general paradigm of braneworlds, and introduce the Randall-Sundrum model. I discuss braneworld gravity, both using perturbation theory, and also non perturbative results. I then discuss black holes on the brane, the obstructions to finding exact solutions, and ways of tackling these difficulties. I describe some known solutions, and conclude with some open questions and controversies.

  13. Black Hole Induced Ejections

    OpenAIRE

    Pelletier, G.

    2004-01-01

    Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull astrophysical phenomena such as AGNs, micro- quasars and GRBs where relativistic ejections are observed, are at the heart of high energy a...

  14. Charged Galileon black holes

    Science.gov (United States)

    Babichev, Eugeny; Charmousis, Christos; Hassaine, Mokhtar

    2015-05-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematically compatible with the field equations. This opens up the possibility for novel searches of hairy black holes in a far more general setting of Horndeski theory.

  15. Ultramassive Black Hole Coalescence

    CERN Document Server

    Khan, Fazeel; Berczik, Peter

    2015-01-01

    Although supermassive black holes (SMBHs) correlate well with their host galaxies, there is an emerging view that outliers exist. Henize 2-10, NGC 4889, and NGC1277 are examples of SMBHs at least an order of magnitude more massive than their host galaxy suggests. The dynamical effects of such ultramassive central black holes is unclear. Here, we perform direct N-body simulations of mergers of galactic nuclei where one black hole is ultramassive to study the evolution of the remnant and the black hole dynamics in this extreme regime. We find that the merger remnant is axisymmetric near the center, while near the large SMBH influence radius, the galaxy is triaxial. The SMBH separation shrinks rapidly due to dynamical friction, and quickly forms a binary black hole; if we scale our model to the most massive estimate for the NGC1277 black hole, for example, the timescale for the SMBH separation to shrink from nearly a kiloparsec to less than a parsec is roughly 10 Myr. By the time the SMBHs form a hard binary, gr...

  16. Topological Analysis of Urban Drainage Networks

    Science.gov (United States)

    Yang, Soohyun; Paik, Kyungrock; McGrath, Gavan; Rao, Suresh

    2016-04-01

    Urban drainage networks are an essential component of infrastructure, and comprise the aggregation of underground pipe networks carrying storm water and domestic waste water for eventual discharge to natural stream networks. Growing urbanization has contributed to rapid expansion of sewer networks, vastly increasing their complexity and scale. Importance of sewer networks has been well studied from an engineering perspective, including resilient management, optimal design, and malfunctioning impact. Yet, analysis of the urban drainage networks using complex networks approach are lacking. Urban drainage networks consist of manholes and conduits, which correspond to nodes and edges, analogous to junctions and streams in river networks. Converging water flows in these two networks are driven by elevation gradient. In this sense, engineered urban drainage networks share several attributes of flows in river networks. These similarities between the two directed, converging flow networks serve the basis for us to hypothesize that the functional topology of sewer networks, like river networks, is scale-invariant. We analyzed the exceedance probability distribution of upstream area for practical sewer networks in South Korea. We found that the exceedance probability distributions of upstream area follow power-law, implying that the sewer networks exhibit topological self-similarity. The power-law exponents for the sewer networks were similar, and within the range reported from analysis of natural river networks. Thus, in line with our hypothesis, these results suggest that engineered urban drainage networks share functional topological attributes regardless of their structural dissimilarity or different underlying network evolution processes (natural vs. engineered). Implications of these findings for optimal design of sewer networks and for modeling sewer flows will be discussed.

  17. Florentine Renaissance Resources. Online Tratte of Office Holders 1282-1532, Ed. by D. Herlihy, R. Burr Litchfield, A. Molho, R. Barducci, 2000. Online Catasto of 1427, Ed. by D. Herlihy, C. Klapisch-Zuber, Vers. 1.2., Brown University, Providence, R.I.

    Directory of Open Access Journals (Sweden)

    Marco Bicchierai

    2002-12-01

    Full Text Available Florentine Renaissance Resources. - Online Tratte of Office Holders 1282-1532, Edited by David Herlihy, R. Burr Litchfield, Anthony Molho and Roberto Barducci , 2000 - Online Catasto of 1427, Edited by David Herlihy, Christiane Klapisch-Zuber, Version 1.2., Brown University, Providence, R.I. , 1996

  18. Experimental Study on Burrs in Micro-milling Nickel-base Superalloy Inconel718%镍基高温合金Inconel718微铣削毛刺试验研究∗

    Institute of Scientific and Technical Information of China (English)

    卢晓红; 武文毅; 王文韬; 裴兴林; 路彦君; 司立坤

    2015-01-01

    基于微小型机床的微铣削( Micro-milling )技术是加工镍基高温合金微小结构/零件的可行技术手段。文章通过镍基高温合金微铣削加工实验,利用扫描电子显微镜和能谱分析仪对刀具的磨、破损形态及局部化学成分和槽的表面形貌进行了研究分析,发现镍基高温合金微铣削毛刺形貌及成因与镍基高温合金传统切削或其他材料微铣削具有很大不同:首先,毛刺长度过长;其次,刀具磨损对鳞刺的产生有很大影响;鳞刺只出现在槽的一侧边界。在实验研究基础上,分析了毛刺的成因,为后续镍基高温合金微铣削毛刺的有效抑制研究提供参考。%Micro milling technology which is based on the micro machine tool is one of the feasible skills processing the Nickel-based superalloy micro constructions/parts. Micro-milling Nickel-based superalloy tests have been carried out and then the wear/break features and the chemical component of the testing tool as well as the surface features of the testing slots have been researched. Results show that the burrs’ features and causes in micro milling Nickel-based superalloy have great differences from the traditionally milling Nickel-based superalloy and micro milling other materials. Firstly, the length of the burrs is too long. Sec-ondly, tool wearing has great effects on the scales’ formation. Thirdly, the scales only appear on the one side of the testing slots. Based on the tests and researches, formation of the burrs has been studied to provide references for controlling the burrs in micro milling Nickel-based superalloy effectively.

  19. Cosmic censorship inside black holes

    CERN Document Server

    Thorlacius, L

    2006-01-01

    A simple argument is given that a traversable Cauchy horizon inside a black hole is incompatible with unitary black hole evolution. The argument assumes the validity of black hole complementarity and applies to a generic black hole carrying angular momentum and/or charge. In the second part of the paper we review recent work on the semiclassical geometry of two-dimensional charged black holes.

  20. Black holes and beyond

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-02-01

    Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for

  1. 46 CFR 178.420 - Drainage of cockpit vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Drainage of cockpit vessels. 178.420 Section 178.420... TONS) INTACT STABILITY AND SEAWORTHINESS Drainage of Weather Decks § 178.420 Drainage of cockpit vessels. (a) Except as follows, the cockpit on a cockpit vessel may be watertight: (1) A cockpit may...

  2. Black Holes and Beyond

    CERN Document Server

    Mathur, Samir D

    2012-01-01

    The black hole information paradox forces us into a strange situation: we must find a way to break the semiclassical approximation in a domain where no quantum gravity effects would normally be expected. Traditional quantizations of gravity do not exhibit any such breakdown, and this forces us into a difficult corner: either we must give up quantum mechanics or we must accept the existence of troublesome `remnants'. In string theory, however, the fundamental quanta are extended objects, and it turns out that the bound states of such objects acquire a size that grows with the number of quanta in the bound state. The interior of the black hole gets completely altered to a `fuzzball' structure, and information is able to escape in radiation from the hole. The semiclassical approximation can break at macroscopic scales due to the large entropy of the hole: the measure in the path integral competes with the classical action, instead of giving a subleading correction. Putting this picture of black hole microstates ...

  3. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2009-05-01

    The final merger of two black holes is expected to be the strongest gravitational wave source for ground-based interferometers such as LIGO, VIRGO, and GEO600, as well as the space-based LISA. Observing these sources with gravitational wave detectors requires that we know the radiation waveforms they emit. And, when the black holes merge in the presence of gas and magnetic fields, various types of electromagnetic signals may also be produced. Since these mergers take place in regions of extreme gravity, we need to solve Einstein's equations of general relativity on a computer. For more than 30 years, scientists have tried to compute black hole mergers using the methods of numerical relativity. The resulting computer codes have been plagued by instabilities, causing them to crash well before the black holes in the binary could complete even a single orbit. Within the past few years, however, this situation has changed dramatically, with a series of remarkable breakthroughs. This talk will focus on new simulations that are revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics.

  4. Charged Galileon black holes

    CERN Document Server

    Babichev, Eugeny; Hassaine, Mokhtar

    2015-01-01

    We consider an Abelian gauge field coupled to a particular truncation of Horndeski theory. The Galileon field has translation symmetry and couples non minimally both to the metric and the gauge field. When the gauge-scalar coupling is zero the gauge field reduces to a standard Maxwell field. By taking into account the symmetries of the action, we construct charged black hole solutions. Allowing the scalar field to softly break symmetries of spacetime we construct black holes where the scalar field is regular on the black hole event horizon. Some of these solutions can be interpreted as the equivalent of Reissner-Nordstrom black holes of scalar tensor theories with a non trivial scalar field. A self tuning black hole solution found previously is extended to the presence of dyonic charge without affecting whatsoever the self tuning of a large positive cosmological constant. Finally, for a general shift invariant scalar tensor theory we demonstrate that the scalar field Ansatz and method we employ are mathematic...

  5. Numerical simulation of transient flow in horizontal drainage systems

    Institute of Scientific and Technical Information of China (English)

    Ze-yu MAO; Han XIAO; Ying LIU; Ying-jun HU

    2009-01-01

    A numerical simulation model based on the characteristic-based finite-difference method with a time-line interpolation scheme was developed for predicting transient free surface flow in horizontal drainage systems. The fundamental accuracy of the numerical model was first clarified by comparison with the experimental results for a single drainage pipe. Boundary conditions for junctions and bends, which are often encountered in drainage systems, were studied both experimentally and numerically. The numerical model was applied to an actual drainage system. Comparison with a full-scale model experiment indicates that the model can be used to accurately predict flow characteristics in actual drainage networks.

  6. Range of drainage effect of surface mines

    Energy Technology Data Exchange (ETDEWEB)

    Sozanski, J.

    1978-03-01

    This paper discusses methods of calculating the range of effects of water drainage from surface coal mines and other surface mines. It is suggested that methods based on test pumping (water drainage) are time consuming, and the results can be distorted by atmospheric factors such as rain fall or dry period. So-called empirical formulae produce results which are often incorrect. The size of a cone shaped depression calculated on the basis of empirical formulae can be ten times smaller than the size of the real depression. It is suggested that using a formula based on the Dupuit formula is superior to other methods of depression calculation. According to the derived formulae the radius of the depresion cone is a function of parameters of the water bearing horizons, size of surface mine working and of water depression. The proposed formula also takes into account the influence of atmospheric factors (water influx caused by precipitation, etc.). (1 ref.) (In Polish)

  7. Thermokarst lakes, drainage, and drained basins

    Science.gov (United States)

    Grosse, G.; Jones, B.; Arp, C.; Shroder, John F.

    2013-01-01

    Thermokarst lakes and drained lake basins are widespread in Arctic and sub-Arctic permafrost lowlands with ice-rich sediments. Thermokarst lake formation is a dominant mode of permafrost degradation and is linked to surface disturbance, subsequent melting of ground ice, surface subsidence, water impoundment, and positive feedbacks between lake growth and permafrost thaw, whereas lake drainage generally results in local permafrost aggradation. Thermokarst lakes characteristically have unique limnological, morphological, and biogeochemical characteristics that are closely tied to cold-climate conditions and permafrost properties. Thermokarst lakes also have a tendency toward complete or partial drainage through permafrost degradation and erosion. Thermokarst lake dynamics strongly affect the development of landscape geomorphology, hydrology, and the habitat characteristic of permafrost lowlands.

  8. Black Hole Induced Ejections

    CERN Document Server

    Pelletier, G

    2004-01-01

    Black Holes generate a particular kind of environments dominated by an accretion flow which concentrates a magnetic field. The interplay of gravity and magnetism creates this paradoxical situation where relativistic ejection is allowed and consequently high energy phenomena take place. Therefore Black Holes, which are very likely at the origin of powerfull astrophysical phenomena such as AGNs, micro- quasars and GRBs where relativistic ejections are observed, are at the heart of high energy astrophysics. The combination of General Relativity and Magneto-HydroDynamics (MHD) makes theory difficult; however great pionneers opened beautiful tracks in the seventies and left important problems to be solved for the next decades. These lectures will present the status of these issues. They have a tutorial aspect together with critical review aspect and contain also some new issues. Most of these lectures has been presented at the "School on Black Hole in the Universe" at Cargese, in May 2003.

  9. Janus black holes

    Science.gov (United States)

    Bak, Dongsu; Gutperle, Michael; Janik, Romuald A.

    2011-10-01

    In this paper Janus black holes in A dS 3 are considered. These are static solutions of an Einstein-scalar system with broken translation symmetry along the horizon. These solutions are dual to interface conformal field theories at finite temperature. An approximate solution is first constructed using perturbation theory around a planar BTZ blackhole. Numerical and exact solutions valid for all sets of parameters are then found and compared. Using the exact solution the thermodynamics of the system is analyzed. The entropy associated with the Janus black hole is calculated and it is found that the entropy of the black Janus is the sum of the undeformed black hole entropy and the entanglement entropy associated with the defect.

  10. Turbulent black holes.

    Science.gov (United States)

    Yang, Huan; Zimmerman, Aaron; Lehner, Luis

    2015-02-27

    We demonstrate that rapidly spinning black holes can display a new type of nonlinear parametric instability-which is triggered above a certain perturbation amplitude threshold-akin to the onset of turbulence, with possibly observable consequences. This instability transfers from higher temporal and azimuthal spatial frequencies to lower frequencies-a phenomenon reminiscent of the inverse cascade displayed by (2+1)-dimensional fluids. Our finding provides evidence for the onset of transitory turbulence in astrophysical black holes and predicts observable signatures in black hole binaries with high spins. Furthermore, it gives a gravitational description of this behavior which, through the fluid-gravity duality, can potentially shed new light on the remarkable phenomena of turbulence in fluids.

  11. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  12. Black hole entropy quantization

    CERN Document Server

    Corichi, A; Fernandez-Borja, E; Corichi, Alejandro; Diaz-Polo, Jacobo; Fernandez-Borja, Enrique

    2006-01-01

    Ever since the pioneer works of Bekenstein and Hawking, black hole entropy has been known to have a quantum origin. Furthermore, it has long been argued by Bekenstein that entropy should be quantized in discrete (equidistant) steps given its identification with horizon area in (semi-)classical general relativity and the properties of area as an adiabatic invariant. This lead to the suggestion that black hole area should also be quantized in equidistant steps to account for the discrete black hole entropy. Here we shall show that loop quantum gravity, in which area is not quantized in equidistant steps can nevertheless be consistent with Bekenstein's equidistant entropy proposal in a subtle way. For that we perform a detailed analysis of the number of microstates compatible with a given area and show that an observed oscillatory behavior in the entropy-area relation, when properly interpreted yields an entropy that has discrete, equidistant values that are consistent with the Bekenstein framework.

  13. Black hole accretion discs

    CERN Document Server

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. outbursting black-hole low-mass X-ray binaries. We then turn to the role of advection in accretion flow onto black holes illustrating its action and importance with a toy model describing both ADAFs and slim discs. We conclude with a presentation of the general-relativistic formalism describing accretion discs in the Kerr space-time.

  14. Black hole gravitohydromagnetics

    CERN Document Server

    Punsly, Brian

    2008-01-01

    Black hole gravitohydromagnetics (GHM) is developed from the rudiments to the frontiers of research in this book. GHM describes plasma interactions that combine the effects of gravity and a strong magnetic field, in the vicinity (ergosphere) of a rapidly rotating black hole. This topic was created in response to the astrophysical quest to understand the central engines of radio loud extragalactic radio sources. The theory describes a "torsional tug of war" between rotating ergospheric plasma and the distant asymptotic plasma that extracts the rotational inertia of the black hole. The recoil from the struggle between electromagnetic and gravitational forces near the event horizon is manifested as a powerful pair of magnetized particle beams (jets) that are ejected at nearly the speed of light. These bipolar jets feed large-scale magnetized plasmoids on scales as large as millions of light years (the radio lobes of extragalactic radio sources). This interaction can initiate jets that transport energy fluxes exc...

  15. The closest black holes

    CERN Document Server

    Fender, Rob; Heywood, Ian

    2013-01-01

    Starting from the assumption that there is a large population (> 10^8) of isolated, stellar-mass black holes (IBH) distributed throughout our galaxy, we consider the detectable signatures of accretion from the interstellar medium (ISM) that may be associated with such a population. We simulate the nearby (radius 250 pc) part of this population, corresponding to the closest ~35 000 black holes, using current best estimates of the mass distribution of stellar mass black holes combined with two models for the velocity distribution of stellar-mass IBH which bracket likely possibilities. We distribute this population of objects appropriately within the different phases of the ISM and calculate the Bondi-Hoyle accretion rate, modified by a further dimensionless efficiency parameter \\lambda. Assuming a simple prescription for radiatively inefficient accretion at low Eddington ratios, we calculate the X-ray luminosity of these objects, and similarly estimate the radio luminosity from relations found empirically for b...

  16. Urban drainage models - making uncertainty analysis simple

    DEFF Research Database (Denmark)

    Vezzaro, Luca; Mikkelsen, Peter Steen; Deletic, Ana;

    2012-01-01

    There is increasing awareness about uncertainties in modelling of urban drainage systems and, as such, many new methods for uncertainty analyses have been developed. Despite this, all available methods have limitations which restrict their widespread application among practitioners. Here, a modif...... probability distributions (often used for sensitivity analyses) and prediction intervals. To demonstrate the new method, it is applied to a conceptual rainfall-runoff model using a dataset collected from Melbourne, Australia....

  17. Drawdown behavior of gravity drainage wells

    Energy Technology Data Exchange (ETDEWEB)

    Aasen, J.A.; Ramey, H.J. Jr.

    1993-10-01

    An analytical solution for drawdown in gravity drainage wells is developed. The free-surface flow is viewed as incompressible, and anisotropy effects are included. The well is a line source well, and the reservoir is infinitely large. The model is valid for small drawdowns. The uniform wellbore potential inner boundary condition is modelled using the proper Green`s function. The discontinuity at the wellbore is solved by introducing a finite skin radius, and the formulation produces a seepage face. The calculated wellbore flux distribution and wellbore pressures are in fair agreement with results obtained using a numerical gravity drainage simulator. Three distinct flow periods are observed. The wellbore storage period is caused by the moving liquid level, and the duration is short. During the long intermediate flow period, the wellbore pressure is nearly constant. In this period the free surface moves downwards, and the liquid is produced mainly by vertical drainage. At long times the semilog straight line appears. The confined liquid solutions by Theis (1935) and van Everdingen and Hurst (1949) may be used during the pseudoradial flow period if the flowrate is low. New type curves are presented that yield both vertical and horizontal permeabilities.

  18. Drainage and Stratification Kinetics of Foam Films

    Science.gov (United States)

    Zhang, Yiran; Sharma, Vivek

    2014-03-01

    Baking bread, brewing cappuccino, pouring beer, washing dishes, shaving, shampooing, whipping eggs and blowing bubbles all involve creation of aqueous foam films. Foam lifetime, drainage kinetics and stability are strongly influenced by surfactant type (ionic vs non-ionic), and added proteins, particles or polymers modify typical responses. The rate at which fluid drains out from a foam film, i.e. drainage kinetics, is determined in the last stages primarily by molecular interactions and capillarity. Interestingly, for certain low molecular weight surfactants, colloids and polyelectrolyte-surfactant mixtures, a layered ordering of molecules, micelles or particles inside the foam films leads to a stepwise thinning phenomena called stratification. Though stratification is observed in many confined systems including foam films containing particles or polyelectrolytes, films containing globular proteins seem not to show this behavior. Using a Scheludko-type cell, we experimentally study the drainage and stratification kinetics of horizontal foam films formed by protein-surfactant mixtures, and carefully determine how the presence of proteins influences the hydrodynamics and thermodynamics of foam films.

  19. Growth of Primordial Black Holes

    Science.gov (United States)

    Harada, Tomohiro

    Primordial black holes have important observational implications through Hawking evaporation and gravitational radiation as well as being a candidate for cold dark matter. Those black holes are assumed to have formed in the early universe typically with the mass scale contained within the Hubble horizon at the formation epoch and subsequently accreted mass surrounding them. Numerical relativity simulation shows that primordial black holes of different masses do not accrete much, which contrasts with a simplistic Newtonian argument. We see that primordial black holes larger than the 'super-horizon' primordial black holes have decreasing energy and worm-hole like struture, suggesting the formation through quamtum processes.

  20. Over spinning a black hole?

    Energy Technology Data Exchange (ETDEWEB)

    Bouhmadi-Lopez, Mariam; Cardoso, Vitor; Nerozzi, Andrea; Rocha, Jorge V, E-mail: mariam.bouhmadi@ist.utl.pt, E-mail: vitor.cardoso@ist.utl.pt, E-mail: andrea.nerozzi@ist.utl.pt, E-mail: jorge.v.rocha@ist.utl.pt [CENTRA, Department de Fisica, Instituto Superior Tecnico, Av. Rovisco Pais 1, 1049 Lisboa (Portugal)

    2011-09-22

    A possible process to destroy a black hole consists on throwing point particles with sufficiently large angular momentum into the black hole. In the case of Kerr black holes, it was shown by Wald that particles with dangerously large angular momentum are simply not captured by the hole, and thus the event horizon is not destroyed. Here we reconsider this gedanken experiment for black holes in higher dimensions. We show that this particular way of destroying a black hole does not succeed and that Cosmic Censorship is preserved.

  1. Treatment of severe acute pancreatitis through retroperitoneal laparoscopic drainage

    Institute of Scientific and Technical Information of China (English)

    Chun Tang; Baolin Wang; Bing Xie; Hongming Liu; Ping Chen

    2011-01-01

    A treatment method based on drainage via retroperitoneal laparoscopy was adopted for 15 severe acute pancreatitis (SAP) patients to investigate the feasibility of the method.Ten patients received only drainage via retroperitoneai laparoscopy,four patients received drainage via both retroperitoneal and preperitoneal laparoscopy,and one patient received drainage via conversion to laparotomy.Thirteen patients exhibited a good drainage effect and were successfully cured without any other surgical treatment.Two patients had encapsulated effusions or pancreatic pseudocysts after surgery,but were successfully cured after lavage and B ultrasound-guided percutaneous catheter drainage.SAP treatment via retroperitoneal laparoscopic drainage is an effective surgical method,resulting in minor injury.

  2. Horndeski black hole geodesics

    CERN Document Server

    Tretyakova, D A

    2016-01-01

    We examine geodesics for the scalar-tensor black holes in the Horndeski-Galileon framework. Our analysis shows that first kind relativistic orbits may not be present within some model parameters range. This is a highly pathological behavior contradicting to the black hole accretion and Solar System observations. We also present a new (although very similar to those previously known) solution, which contains the orbits we expect from a compact object, admits regular scalar field at the horizon and and can fit into the known stability criteria.

  3. Are Black Holes Springy?

    CERN Document Server

    Good, Michael R R

    2014-01-01

    A $(3+1)$-dimensional asymptotically flat Kerr black hole angular speed $\\Omega_+$ can be used to define an effective spring constant, $k=m\\Omega_+^2$. Its maximum value is the Schwarzschild surface gravity, $k = \\kappa $, which rapidly weakens as the black hole spins down and the temperature increases. The Hawking temperature is expressed in terms of the spring constant: $2\\pi T = \\kappa - k$. Hooke's law, in the extremal limit, provides the force $F = 1/4$, which is consistent with the conjecture of maximum force in general relativity.

  4. Acoustic black holes

    CERN Document Server

    Visser, M

    1999-01-01

    Acoustic propagation in a moving fluid provides a conceptually clean and powerful analogy for understanding black hole physics. As a teaching tool, the analogy is useful for introducing students to both General Relativity and fluid mechanics. As a research tool, the analogy helps clarify what aspects of the physics are kinematics and what aspects are dynamics. In particular, Hawking radiation is a purely kinematical effect, whereas black hole entropy is intrinsically dynamical. Finally, I discuss the fact that with present technology acoustic Hawking radiation is almost experimentally testable.

  5. Superfluid Black Holes

    CERN Document Server

    Hennigar, Robie A; Tjoa, Erickson

    2016-01-01

    We present what we believe is the first example of a "$\\lambda$-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid $^4$He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically AdS hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  6. Superfluid Black Holes.

    Science.gov (United States)

    Hennigar, Robie A; Mann, Robert B; Tjoa, Erickson

    2017-01-13

    We present what we believe is the first example of a "λ-line" phase transition in black hole thermodynamics. This is a line of (continuous) second order phase transitions which in the case of liquid ^{4}He marks the onset of superfluidity. The phase transition occurs for a class of asymptotically anti-de Sitter hairy black holes in Lovelock gravity where a real scalar field is conformally coupled to gravity. We discuss the origin of this phase transition and outline the circumstances under which it (or generalizations of it) could occur.

  7. Magnonic Black Holes.

    Science.gov (United States)

    Roldán-Molina, A; Nunez, Alvaro S; Duine, R A

    2017-02-10

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons-the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  8. Characterizing Black Hole Mergers

    Science.gov (United States)

    Baker, John; Boggs, William Darian; Kelly, Bernard

    2010-01-01

    Binary black hole mergers are a promising source of gravitational waves for interferometric gravitational wave detectors. Recent advances in numerical relativity have revealed the predictions of General Relativity for the strong burst of radiation generated in the final moments of binary coalescence. We explore features in the merger radiation which characterize the final moments of merger and ringdown. Interpreting the waveforms in terms of an rotating implicit radiation source allows a unified phenomenological description of the system from inspiral through ringdown. Common features in the waveforms allow quantitative description of the merger signal which may provide insights for observations large-mass black hole binaries.

  9. Modeling black hole evaporation

    CERN Document Server

    Fabbri, Alessandro

    2005-01-01

    The scope of this book is two-fold: the first part gives a fully detailed and pedagogical presentation of the Hawking effect and its physical implications, and the second discusses the backreaction problem, especially in connection with exactly solvable semiclassical models that describe analytically the black hole evaporation process. The book aims to establish a link between the general relativistic viewpoint on black hole evaporation and the new CFT-type approaches to the subject. The detailed discussion on backreaction effects is also extremely valuable.

  10. Magnonic Black Holes

    Science.gov (United States)

    Roldán-Molina, A.; Nunez, Alvaro S.; Duine, R. A.

    2017-02-01

    We show that the interaction between the spin-polarized current and the magnetization dynamics can be used to implement black-hole and white-hole horizons for magnons—the quanta of oscillations in the magnetization direction in magnets. We consider three different systems: easy-plane ferromagnetic metals, isotropic antiferromagnetic metals, and easy-plane magnetic insulators. Based on available experimental data, we estimate that the Hawking temperature can be as large as 1 K. We comment on the implications of magnonic horizons for spin-wave scattering and transport experiments, and for magnon entanglement.

  11. Correlated Multiphoton Holes

    CERN Document Server

    Afek, Itai; Silberberg, Yaron

    2010-01-01

    We generate bipartite states of light which exhibit an absence of multiphoton coincidence events between two modes amid a constant background flux. These `correlated photon holes' are produced by mixing a coherent state and relatively weak spontaneous parametric down-conversion using a balanced beamsplitter. Correlated holes with arbitrarily high photon numbers may be obtained by adjusting the relative phase and amplitude of the inputs. We measure states of up to five photons and verify their nonclassicality. The scheme provides a route for observation of high-photon-number nonclassical correlations without requiring intense quantum resources.

  12. Preoperative biliary drainage for periampullary tumors causing obstructive jaundice; DRainage vs. (direct OPeration (DROP-trial

    Directory of Open Access Journals (Sweden)

    Sosef Meindert N

    2007-03-01

    Full Text Available Abstract Background Surgery in patients with obstructive jaundice caused by a periampullary (pancreas, papilla, distal bile duct tumor is associated with a higher risk of postoperative complications than in non-jaundiced patients. Preoperative biliary drainage was introduced in an attempt to improve the general condition and thus reduce postoperative morbidity and mortality. Early studies showed a reduction in morbidity. However, more recently the focus has shifted towards the negative effects of drainage, such as an increase of infectious complications. Whether biliary drainage should always be performed in jaundiced patients remains controversial. The randomized controlled multicenter DROP-trial (DRainage vs. Operation was conceived to compare the outcome of a 'preoperative biliary drainage strategy' (standard strategy with that of an 'early-surgery' strategy, with respect to the incidence of severe complications (primary-outcome measure, hospital stay, number of invasive diagnostic tests, costs, and quality of life. Methods/design Patients with obstructive jaundice due to a periampullary tumor, eligible for exploration after staging with CT scan, and scheduled to undergo a "curative" resection, will be randomized to either "early surgical treatment" (within one week or "preoperative biliary drainage" (for 4 weeks and subsequent surgical treatment (standard treatment. Primary outcome measure is the percentage of severe complications up to 90 days after surgery. The sample size calculation is based on the equivalence design for the primary outcome measure. If equivalence is found, the comparison of the secondary outcomes will be essential in selecting the preferred strategy. Based on a 40% complication rate for early surgical treatment and 48% for preoperative drainage, equivalence is taken to be demonstrated if the percentage of severe complications with early surgical treatment is not more than 10% higher compared to standard treatment

  13. Mineralogical correlation of surficial sediment from area drainages with selected sedimentary interbeds at the Idaho National Engineering Laboratory, Idaho

    Energy Technology Data Exchange (ETDEWEB)

    Bartholomay, R.C.

    1990-08-01

    Ongoing research by the US Geological Survey at the INEL involves investigation of the migration of radioactive elements contained in low-level radioactive waste, hydrologic and geologic factors affecting waste movement, and geochemical factors that influence the chemical composition of the waste. Identification of the mineralogy of the Snake River Plain is needed to aid in the study of the hydrology and geochemistry of subsurface waste disposal. The US Geological Surveys project office at the Idaho National Engineering Laboratory, in cooperation with the US Department of Energy, used mineralogical data to correlate surficial sediment samples from the Big Lost River, Little Lost River, and Birch Greek drainages with selected sedimentary interbed core samples taken from test holes at the RWMC (Radioactive Waste Management Complex), TRA (Test Reactors Area), ICPP (Idaho Chemical Processing Plant), and TAN (Test Area North). Correlating the mineralogy of a particular present-day drainage area with a particular sedimentary interbed provides information on historical source of sediment for interbeds in and near the INEL. Mineralogical data indicate that surficial sediment samples from the Big Lost River drainage contained a larger amount of feldspar and pyroxene and a smaller amount of calcite and dolomite than samples from the Little Lost River and Birch Creek drainages. Mineralogical data from sedimentary interbeds at the RWMC, TRA, and ICPP correlate with surficial sediment of the present-day big Lost River drainage. Mineralogical data from a sedimentary interbed at TAN correlate with surficial sediment of the present-day Birch Creek drainage. 13 refs., 5 figs., 3 tabs.

  14. Evaluación de la reproducción inducida del blanquillo ( Sorubim cuspicaudus Littmann, Burr Nass, 2000 con ovaprim®.

    Directory of Open Access Journals (Sweden)

    Víctor Atencio G

    2003-01-01

    Full Text Available El blanquillo ( Sorubim suspicaudus Littmann, Burr &Nass, 2000 presenta características de importanciapara la acuicultura, destacándose la calidad de sucarne y el alto valor comercial. No se reproduce enconfinamiento, por lo que es necesario sureproducción inducida con sustancias hormonales.Responde bien a la inducción con extracto de pituitariade capa (EPC; sin embargo, no se ha evaluado suinducción con extracto de análogos deGonodotropine Releasing Hormone de salmón(sGnRH-a y domperidone en un vehículo inerte. Porlo tanto, entre mayo y noviembre/02, se evaluó eldesempeño reproductivo del blanquillo inducido condiferentes dosificaciones de Ovaprim®: 0.25 (T2,0.050 (T3 y 0.75 ml/kg de peso vivo (T4, aplicadoen una sola dosificación, por inyección en la basede la aleta pectoral. Además, un grupo fue inducidocon 8 mg EPC/kg de peso vivo (TI, en dos inyeccionesde 10 y7 90% de la dosis total, con intervalo de 6horas, por vía intramuscular. Se indujeron entre seisy nueve hembras por tratamiento con igual númerode machos. El desempeño reproductivo fue evaluadomediante el índice de ovulación (hembras ovuladas/hembras tratadas, tasa de fertilización medida a las4 horas pos-eclosión (HPF, tasa de eclosión medidaa las 10 HPF y la fecundidad tanto absoluta comorelativa. El Ovaprim® mostró ser efectivo para inducirla ovulación del blanquillo en las dosificacionesevaluadas (0.25 a 0.75 mL/kg, con respuestassimilares en el desempeño reproductivo a lasobtenidas en EPC. La ovulación con Ovaprim® seobtuvo entre las 12.8 y 14.0 horas con temperaturapromedio del agua de 27.3ºC. El índice de ovulaciónosciló entre 66.7% (T2 y 83.3% (T3; la tasa defertilización osciló entre 88.0% (T3 y 42.0% (T1; latasa de eclosión osciló entre 83.7% (T3 y 40.3%(T1;la fecundidad absoluta osciló entre 40370.6 (T1 y82992.5 ovocitos/hembra (T2; la fecundad relativa,expresada en gramos de ovocitos/kg de hembra,osciló entre 32.1 (T3 y 63.1(T2; el di

  15. Electron hole tracking PIC simulation

    Science.gov (United States)

    Zhou, Chuteng; Hutchinson, Ian

    2016-10-01

    An electron hole is a coherent BGK mode solitary wave. Electron holes are observed to travel at high velocities relative to bulk plasmas. The kinematics of a 1-D electron hole is studied using a novel Particle-In-Cell simulation code with fully kinetic ions. A hole tracking technique enables us to follow the trajectory of a fast-moving solitary hole and study quantitatively hole acceleration and coupling to ions. The electron hole signal is detected and the simulation domain moves by a carefully designed feedback control law to follow its propagation. This approach has the advantage that the length of the simulation domain can be significantly reduced to several times the hole width, which makes high resolution simulations tractable. We observe a transient at the initial stage of hole formation when the hole accelerates to several times the cold-ion sound speed. Artificially imposing slow ion speed changes on a fully formed hole causes its velocity to change even when the ion stream speed in the hole frame greatly exceeds the ion thermal speed, so there are no reflected ions. The behavior that we observe in numerical simulations agrees very well with our analytic theory of hole momentum conservation and energization effects we call ``jetting''. The work was partially supported by the NSF/DOE Basic Plasma Science Partnership under Grant DE-SC0010491. Computer simulations were carried out on the MIT PSFC parallel AMD Opteron/Infiniband cluster Loki.

  16. When Black Holes Collide

    Science.gov (United States)

    Baker, John

    2010-01-01

    Among the fascinating phenomena predicted by General Relativity, Einstein's theory of gravity, black holes and gravitational waves, are particularly important in astronomy. Though once viewed as a mathematical oddity, black holes are now recognized as the central engines of many of astronomy's most energetic cataclysms. Gravitational waves, though weakly interacting with ordinary matter, may be observed with new gravitational wave telescopes, opening a new window to the universe. These observations promise a direct view of the strong gravitational dynamics involving dense, often dark objects, such as black holes. The most powerful of these events may be merger of two colliding black holes. Though dark, these mergers may briefly release more energy that all the stars in the visible universe, in gravitational waves. General relativity makes precise predictions for the gravitational-wave signatures of these events, predictions which we can now calculate with the aid of supercomputer simulations. These results provide a foundation for interpreting expect observations in the emerging field of gravitational wave astronomy.

  17. Rotating regular black holes

    CERN Document Server

    Bambi, Cosimo

    2013-01-01

    The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this letter, we apply the Newman-Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer-Lindquist coordinates. These special solutions are of Petrov type ...

  18. Moulting Black Holes

    Science.gov (United States)

    Bena, Iosif; Chowdhury, Borun D.; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2012-03-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no black holes were thought to exist.

  19. Rotating regular black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bambi, Cosimo, E-mail: bambi@fudan.edu.cn; Modesto, Leonardo, E-mail: lmodesto@fudan.edu.cn

    2013-04-25

    The formation of spacetime singularities is a quite common phenomenon in General Relativity and it is regulated by specific theorems. It is widely believed that spacetime singularities do not exist in Nature, but that they represent a limitation of the classical theory. While we do not yet have any solid theory of quantum gravity, toy models of black hole solutions without singularities have been proposed. So far, there are only non-rotating regular black holes in the literature. These metrics can be hardly tested by astrophysical observations, as the black hole spin plays a fundamental role in any astrophysical process. In this Letter, we apply the Newman–Janis algorithm to the Hayward and to the Bardeen black hole metrics. In both cases, we obtain a family of rotating solutions. Every solution corresponds to a different matter configuration. Each family has one solution with special properties, which can be written in Kerr-like form in Boyer–Lindquist coordinates. These special solutions are of Petrov type D, they are singularity free, but they violate the weak energy condition for a non-vanishing spin and their curvature invariants have different values at r=0 depending on the way one approaches the origin. We propose a natural prescription to have rotating solutions with a minimal violation of the weak energy condition and without the questionable property of the curvature invariants at the origin.

  20. Twistors and Black Holes

    NARCIS (Netherlands)

    Neitzke, A.; Pioline, B.; Vandoren, S.

    2007-01-01

    Motivated by black hole physics in N = 2,D = 4 supergravity, we study the geometry of quaternionic-K¨ahler manifolds Mobtained by the c-map construction from projective special Kähler manifolds Ms. Improving on earlier treatments, we compute the Käahler potentials on the twistor space Z and Swann sp

  1. Rotating black hole hair

    CERN Document Server

    Gregory, Ruth; Wills, Danielle

    2013-01-01

    A Kerr black hole sporting cosmic string hair is studied in the context of the abelian Higgs model vortex. It is shown that a such a system displays much richer phenomenology than its static Schwarzschild or Reissner--Nordstrom cousins, for example, the rotation generates a near horizon `electric' field. In the case of an extremal rotating black hole, two phases of the Higgs hair are possible: Large black holes exhibit standard hair, with the vortex piercing the event horizon. Small black holes on the other hand, exhibit a flux-expelled solution, with the gauge and scalar field remaining identically in their false vacuum state on the event horizon. This solution however is extremely sensitive to confirm numerically, and we conjecture that it is unstable due to a supperradiant mechanism similar to the Kerr-adS instability. Finally, we compute the gravitational back reaction of the vortex, which turns out to be far more nuanced than a simple conical deficit. While the string produces a conical effect, it is con...

  2. "Holes": Folklore Redux.

    Science.gov (United States)

    Mascia, Elizabeth G.

    2001-01-01

    Demonstrates that a careful reading of the book for young adults, "Holes" by Louis Sachar, reveals how this contemporary story is grounded in folklore, and that it is this debt to folk literature that allows readers to accept an improbable plot. Shows how the story weaves together elements from traditional folk literature and stretches them across…

  3. Fluoroscopy guided percutaneous catheter drainage of pneumothorax in good mid-term patency with tube drainage

    Energy Technology Data Exchange (ETDEWEB)

    Park, Ga Young; Oh, Joo Hyung; Yoon, Yup; Sung, Dong Wook [Kyung Hee University Hospital, Seoul (Korea, Republic of)

    1995-10-15

    To evaluate efficacy and the safety of percutaneous catheter drainage in patients with pneumothorax that is difficult to treat with closed thoracotomy. We retrospectively reviewed effectiveness of percutaneous catheter drainage (PCD) in 10 patients with pneumothorax. The catheter was inserted under fluoroscopic guidance. Seven patients had spontaneous pneumothorax caused by tuberculosis (n =4), reptured bullae (n = 2), and histiocytosis-X (n = 1). Three patients had iatrogenic pneumothorax caused by trauma (n = 1) and surgery (n = 2). All procedures were performed by modified Seldinger's method by using 8F-20F catheter. All catheter were inserted successfully. In 9 of 10 patients, the procedure was curative without further therapy. Duration of catheter insertion ranged from 1 day to 26 days. In the remaining 1 patient in whom multiple pneumothorax occurred after operation, catheter insertion was performed twice. Percutaneous catheter drainage under fluoroscopic guidance is effective and safe procedure for treatment of pneumothorax in patients with failed closed thoracotomy.

  4. Quantum aspects of black holes

    CERN Document Server

    2015-01-01

    Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.

  5. Black Hole: The Interior Spacetime

    CERN Document Server

    Ong, Yen Chin

    2016-01-01

    The information loss paradox is often discussed from the perspective of the observers who stay outside of a black hole. However, the interior spacetime of a black hole can be rather nontrivial. We discuss the open problems regarding the volume of a black hole, and whether it plays any role in information storage. We also emphasize the importance of resolving the black hole singularity, if one were to resolve the information loss paradox.

  6. Switching between hydrophobic and wettable conditions in soil: experiments to assess the influence of cracks, roots and subsurface drainage impedance

    Science.gov (United States)

    Urbanek, E.; Walsh, R. P. D.; Shakesby, R. A.

    2012-04-01

    Although much is known about soil hydrophobicity, assessments of the overall hydrological and erosional significance of the soil property in areas affected by it are greatly hampered by a lack of knowledge on switching between hydrophobic and hydrophilic states. This arises mainly because of (1) the destructive nature of methods of assessing hydrophobicity, (2) its often high local spatial variability and (3) difficulties of relating hydrophobicity results to meaningful soil moisture values. Also, very little is known about the influence which cracks and holes through hydrophobic soil and the presence or absence of subsurface impeding layers have on the 3D pattern and speed of hydrophobicity change during wetting and drying cycles. These issues form the focus of the present paper, which was carried out as part of the EU DESIRE Project. A laboratory experimental approach was adopted. Three different soils of equal initial hydrophibicity class when dry (18 % MED), but of contrasting texture and total carbon content, were investigated: (1) from the scrub-covered (dominated by Erica umbellata, Calluna vulgaris and Pterospartum tridentatum) Vale Torto catchment in Gois municipality, central Portugal (an area where the impacts of prescribed fire were being assessed); (2) soil around a Chamaecyparis lawsonia tree in South Wales; and (3) a vegetated coastal sand-dune location at Nicholaston, Gower Peninsula, South Wales. For the experiments, 106 samples of sieved (< 2 mm), dried soil were placed to a depth of 10 cm in standardized transparent pots (16.5 cm high, top diameter 16 cm, basal diameter 11 cm). Equal numbers of samples were prepared with either (i) five simulated holes, (ii) two simulated linear cracks (in both cases extending downwards to the sample base) and (iii) control soil samples without cracks or holes). Samples were also either (i) sealed at the base to create subsurface impeded drainage or (ii) provided with unimpeded basal drainage by insertion of

  7. Simulations of coalescing black holes

    CERN Document Server

    Janiuk, Agnieszka

    2016-01-01

    We describe the methods and results of numerical simulations of coalescing black holes. The simulation in dynamical spacetime covers the inspiral, merger, and ringdown phases. We analyze the emission of gravitational waves and properties of a black hole being the merger product. We discuss the results in the context of astrophysical environment of black holes that exist in the Universe.

  8. "Exotic" black holes with torsion

    OpenAIRE

    2013-01-01

    In the context of three-dimensional gravity with torsion, the concepts of standard and "exotic" Banados-Teitelboim-Zanelli black holes are generalized by going over to black holes with torsion. This approach provides a unified insight into thermodynamics of black holes, with or without torsion.

  9. Prevention of caval collapse during venous drainage for CPB.

    Science.gov (United States)

    Abdel-Sayed, Saad; Favre, Julien; Taub, Steven; von Segesser, Ludwig-Karl

    2013-01-01

    A new plastic self-expanding Smartcanula (Smartcanula LLC, Lausanne, Switzerland) is designed for central insertion and prevention of caval collapse. The objective of our work is to assess the influence of the new design on atrial chatter. Caval collapse over the entire caval axis, right atrial, hepatic, renal vein, and iliac vein is realized in drainage tubes with holes at 5 cm distance intervals. Smartcanulas with various lengths (26 cm [= right atrial], 34 cm [= hepatic], 43 cm [= renal], and 53 cm [= iliac]) versus two-stage cannulas are compared. Pressure drop (ΔP) is measured using Millar pressure-transducers. Flow rate (Q) is measured using an ultrasonic flow meter. Cannula resistance is defined as the ΔP/Q ratio. Data display and recording are controlled using LabView virtual instruments. At an 88 cm height differential, Q values are 8.69 and 6.8 l/min, and ΔP/Q ratios are 0.63 and 1.28 for the 26-cm Smartcanula and the reference cannula, respectively. The 34-cm Smartcanula showed 8.89 l/min and 0.6 ΔP/Q ratio vs. 7.59 l/min and 0.9 for the control cannula (P < 0.05). The 43-cm and 53-cm Smartcanulas showed Q values of 9.04 and 8.81 l/min, respectively, and ΔP/Q2 ratio of 0.6. The Smartcanula outperforms the two-stage cannula, and direct cannula insertion without guide wire is effective.

  10. Analysis of Cross-Seasonal Spectral Response from Kettle Holes: Application of Remote Sensing Techniques for Chlorophyll Estimation

    Directory of Open Access Journals (Sweden)

    Bernd Lennartz

    2012-11-01

    Full Text Available Kettle holes, small inland water bodies usually less than 1 ha in size, are subjected to pollution, drainage, and structural alteration by intensive land use practices. This study presents the analysis of spectral signatures from kettle holes based on in situ water sampling and reflectance measurements in application for chlorophyll estimation. Water samples and surface reflectance from kettle holes were collected from 6 ponds in 15 field campaigns (5 in 2007 and 10 in 2008, resulting in a total of 80 spectral datasets. We assessed the existing semi-empirical algorithms to determine chlorophyll content for different types of kettle holes using seasonal and cross-seasonal volume reflectance and derivative spectra. Based on this analysis and optical properties of water leaving reflectance from kettle holes, the following typology of the remote signal interpretation was proposed: Submerged vegetation, Phytoplankton dominated and Mixed type.

  11. 加强探放水工作 防治矿井水患%Strengthening water detection and drainage and preventing mine floods

    Institute of Scientific and Technical Information of China (English)

    任兴祎

    2011-01-01

    Integrating with hydrogeological conditions of the mine, this thesis analyzes features of aquifer, carries out water detection and drainage design, and respectively illustrates water detection and drainage drilling design, drill hole layout, and drainage system design and so on, with a view to guide practice, to eliminates mine floods, and to realize safe production as well.%摘要:结合某矿井水文地质实际情况,分析了该矿井含隔水层的特征,在此基础上进行了探放水设计,分别阐述了探放水钻窝设计、钻眼布置及排水系统设计要点等内容,以期指导实践,杜绝矿井水害威胁,实现安全生产。

  12. Ultrasound-guided drainage of deep pelvic abscesses

    DEFF Research Database (Denmark)

    Lorentzen, Torben; Nolsøe, Christian; Skjoldbye, Bjørn

    2011-01-01

    The aim of this study was to demonstrate and evaluate the ultrasound-guided drainage of deep pelvic abscesses in which transabdominal percutaneous access could not be performed because of overlying structures. A retrospective analysis of 32 consecutive patients with 33 deep pelvic abscesses...... (median diameter 7 cm), 19 were treated with catheter drainage and 18 of these cases resulted in favorable clinical outcomes. Of the smaller abscesses (median diameter 4 cm), 14 were treated with needle drainage. In two of these cases, follow-up US showed that a repeat puncture and drainage was necessary...... and the subsequent in-dwelling catheter period, there were no serious complications related to the drainage procedures. We conclude that ultrasound-guided transrectal, transvaginal, transperineal and transgluteal drainage of deep pelvic abscesses are safe and effective treatment approaches. Based on our findings...

  13. Reuse of drainage water model : calculation method of drainage water and watertable depth

    NARCIS (Netherlands)

    Roest, C.W.J.; Rijtema, P.E.; Abdel Khalik, M.A.

    1986-01-01

    The main objective of the project is to assist the Ministry of Irrigation in Egypt in the planning of future watermanagement strategies incorporating reuse of drainage water practices. In order to achieve this main objective a comprehensive measurement programme has been initiated and a mathematical

  14. Preoperative biliary drainage for periampullary tumors causing obstructive jaundice; DRainage vs. (direct) OPeration (DROP-trial)

    NARCIS (Netherlands)

    N.A. van der Gaag (Niels); S.M.M. de Castro (Steve); E.A.J. Rauws (Erik); M.J. Bruno (Marco); C.H.J. van Eijck (Casper); E.J. Kuipers (Ernst); J.J.G.M. Gerritsen (Josephus); J.P. Rutten (Joost Paul); J.W. Greve; E.J. Hesselink (Eric); J.H. Klinkenbijl (Jean); I.H.M.B. Rinkes; D. Boerma (Djamila); B.A. Bonsing (Bert); C.J. van Laarhoven (Cees); F.J. Kubben; E. van der Harst (Erwin); M.N. Sosef (Meindert); K. Bosscha (Koop); I.H.J.T. de Hingh (Ignace); L. Th de Wit (Laurens); O.M. van Delden (Otto); O.R.C. Busch (Olivier); T.M. van Gulik (Thomas); P.M.M. Bossuyt (Patrick); D.J. Gouma (Dirk)

    2007-01-01

    textabstractBackground. Surgery in patients with obstructive jaundice caused by a periampullary (pancreas, papilla, distal bile duct) tumor is associated with a higher risk of postoperative complications than in non-jaundiced patients. Preoperative biliary drainage was introduced in an attempt to im

  15. Optical black hole lasers

    CERN Document Server

    Faccio, Daniele; Lamperti, Marco; Leonhardt, Ulf

    2012-01-01

    Using numerical simulations we show how to realise an optical black hole laser, i.e. an amplifier formed by travelling refractive index perturbations arranged so as to trap light between a white and a black hole horizon. The simulations highlight the main features of these lasers: the growth inside the cavity of positive and negative frequency modes accompanied by a weaker emission of modes that occurs in periodic bursts corresponding to the cavity round trips of the trapped modes. We then highlight a new regime in which the trapped mode spectra broaden until the zero-frequency points on the dispersion curve are reached. Amplification at the horizon is highest for zero-frequencies, therefore leading to a strong modification of the structure of the trapped light. For sufficiently long propagation times, lasing ensues only at the zero-frequency modes.

  16. Presentism meets black holes

    CERN Document Server

    Romero, Gustavo E

    2014-01-01

    Presentism is, roughly, the metaphysical doctrine that maintains that whatever exists, exists in the present. The compatibility of presentism with the theories of special and general relativity was much debated in recent years. It has been argued that at least some versions of presentism are consistent with time-orientable models of general relativity. In this paper we confront the thesis of presentism with relativistic physics, in the strong gravitational limit where black holes are formed. We conclude that the presentist position is at odds with the existence of black holes and other compact objects in the universe. A revision of the thesis is necessary, if it is intended to be consistent with the current scientific view of the universe.

  17. Bilateral subdural effusion and subcutaneous swelling with normally functioning csf shunt.

    Directory of Open Access Journals (Sweden)

    Mitra S

    2001-04-01

    Full Text Available We report a child with hydrocephalus due to tuberculous meningitis who developed a subcutaneous fluid collection around the ventriculoperitoneal shunt tube entry point, after one month of shunting. On investigation, he had decompressed ventricles with bilateral fronto parietal subdural hygroma. Bifrontal burr hole drainage helped resolution of both subdural effusion and subcutaneous scalp swelling. This complication is unique and its pathogenesis has been postulated.

  18. Pancreatic tissue fluid pressure during drainage operations for chronic pancreatitis

    DEFF Research Database (Denmark)

    Ebbehøj, N; Borly, L; Madsen, P

    1990-01-01

    Pancreatic tissue fluid pressure was measured in 10 patients undergoing drainage operations for painful chronic pancreatitis. The pressure was measured by the needle technique in the three anatomic regions of the pancreas before and at different stages of the drainage procedure, and the results...... a decrease in pancreatic tissue fluid pressure during drainage operations for pain in chronic pancreatitis. Regional pressure decrease were apparently unrelated to ERCP findings....

  19. Philosophical Issues of Black Holes

    CERN Document Server

    Romero, Gustavo E

    2014-01-01

    Black holes are extremely relativistic objects. Physical processes around them occur in a regime where the gravitational field is extremely intense. Under such conditions, our representations of space, time, gravity, and thermodynamics are pushed to their limits. In such a situation philosophical issues naturally arise. In this chapter I review some philosophical questions related to black holes. In particular, the relevance of black holes for the metaphysical dispute between presentists and eternalists, the origin of the second law of thermodynamics and its relation to black holes, the problem of information, black holes and hypercomputing, the nature of determinisim, and the breakdown of predictability in black hole space-times. I maintain that black hole physics can be used to illuminate some important problems in the border between science and philosophy, either epistemology and ontology.

  20. Artificial ozone holes

    OpenAIRE

    Dolya, S. N.

    2014-01-01

    This article considers an opportunity of disinfecting a part of the Earth surface, occupying a large area of ten thousand square kilometers. The sunlight will cause dissociation of molecular bromine into atoms; each bromine atom kills thirty thousand molecules of ozone. Each bromine plate has a mass of forty milligrams grams and destroys ozone in the area of hundred square meters. Thus, to form the ozone hole over the area of ten thousand square kilometers, it is required to have the total ma...

  1. Noncommutative Black Holes

    CERN Document Server

    Bastos, C; Dias, N C; Prata, J N

    2010-01-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity regime and it is shown that the wave function vanishes in this limit.

  2. Estudo da influência do diâmetro do orifício piloto na resistência ao arrancamento do parafuso pedicular The influence of pilot hole diameter on screw oullout resistance

    Directory of Open Access Journals (Sweden)

    José Roberto Benites Vendrame

    2008-01-01

    Full Text Available A influência do diâmetro do orifício piloto em relação ao diâmetro interno do parafuso na resistência ao arrancamento do parafuso pedicular foi o objetivo do estudo. Foram utilizados parafusos de 5, 6 e 7 mm do sistema USS de fixação vertebral, os quais foram inseridos nos corpos de prova de madeira, poliuretana e osso. O orifício piloto para a inserção do parafuso foi realizado com brocas de diâmetro inferior, igual e superior ao diâmetro interno do parafuso. Ensaios mecânicos de arrancamento foram realizados em máquina universal de teste. Nos corpos de prova de madeira, poliuretana e osso a realização do orifício piloto com brocas de diâmetro maior que o diâmetro interno do parafuso produziu diminuição da força máxima de arrancamento dos implantes nos ensaios de arrancamento, tendo sido observada diferença estatística. O diâmetro da perfuração do orifício piloto em relação ao diâmetro interno do parafuso exerce influência na resistência ao arrancamento do implante, tendo sido observado aumento da resistência ao arrancamento com a utilização de brocas de diâmetro menor que o diâmetro interno e redução da resistência ao arrancamento com a utilização de brocas com diâmetro maior que o diâmetro interno do parafuso.The influence of the diameter of the pilot hole compared to the inner diameter of the screw on the pull-out resistance of a pedicular screw was studied. 5-, 6-, and 7-mm USS system screws for vertebral fixation were inserted into wood, polyurethane and bone test bodies. The pilot hole for screw insertion was drilled with burrs of smaller, equal or wider diameter than the inner diameter of the screw. Mechanical pull-out assays were performed using a universal testing machine. In the wood, polyurethane and bone test bodies, a pilot hole drilled with burrs of a wider diameter than the inner diameter of the screw produced reduced maximum pull-out strength on the implants, with statistical

  3. Slowly balding black holes

    CERN Document Server

    Lyutikov, Maxim

    2011-01-01

    The "no hair" theorem, a key result in General Relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the "no hair" theorem is not formally applicable for black holes formed from collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively "frozen-in" the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes $N_B = e \\Phi_\\infty /(\\pi c \\hbar)$, where $\\Phi_\\infty \\approx 2 \\pi^2 B_{NS} R_{NS}^3 /(P_{\\rm NS} c)$ is the initial magnetic flux through the hemisphere...

  4. Linear dilaton black holes

    CERN Document Server

    Clément, G; Leygnac, C; Clement, Gerard; Gal'tsov, Dmitri; Leygnac, Cedric

    2003-01-01

    We present new solutions to Einstein-Maxwell-dilaton-axion (EMDA) gravity in four dimensions describing black holes which asymptote to the linear dilaton background. In the non-rotating case they can be obtained as the limiting geometry of dilaton black holes. The rotating solutions (possibly endowed with a NUT parameter) are constructed using a generating technique based on the Sp(4,R) duality of the EMDA system. In a certain limit (with no event horizon present) our rotating solutions coincide with supersymmetric Israel-Wilson-Perjes type dilaton-axion solutions. In presence of an event horizon supersymmetry is broken. The temperature of the static black holes is constant, and their mass does not depend on it, so the heat capacity is zero. We investigate geodesics and wave propagation in these spacetimes and find superradiance in the rotating case. Because of the non-asymptotically flat nature of the geometry, certain modes are reflected from infinity, in particular, all superradiant modes are confined. Thi...

  5. Moulting Black Holes

    CERN Document Server

    Bena, Iosif; de Boer, Jan; El-Showk, Sheer; Shigemori, Masaki

    2011-01-01

    We find a family of novel supersymmetric phases of the D1-D5 CFT, which in certain ranges of charges have more entropy than all known ensembles. We also find bulk BPS configurations that exist in the same range of parameters as these phases, and have more entropy than a BMPV black hole; they can be thought of as coming from a BMPV black hole shedding a "hair" condensate outside of the horizon. The entropy of the bulk configurations is smaller than that of the CFT phases, which indicates that some of the CFT states are lifted at strong coupling. Neither the bulk nor the boundary phases are captured by the elliptic genus, which makes the coincidence of the phase boundaries particularly remarkable. Our configurations are supersymmetric, have non-Cardy-like entropy, and are the first instance of a black hole entropy enigma with a controlled CFT dual. Furthermore, contrary to common lore, these objects exist in a region of parameter space (between the "cosmic censorship bound" and the "unitarity bound") where no b...

  6. Bioreactor for acid mine drainage control

    Science.gov (United States)

    Zaluski, Marek H.; Manchester, Kenneth R.

    2001-01-01

    A bioreactor for reacting an aqueous heavy metal and sulfate containing mine drainage solution with sulfate reducing bacteria to produce heavy metal sulfides and reduce the sulfuric acid content of the solution. The reactor is an elongated, horizontal trough defining an inlet section and a reaction section. An inlet manifold adjacent the inlet section distributes aqueous mine drainage solution into the inlet section for flow through the inlet section and reaction section. A sulfate reducing bacteria and bacteria nutrient composition in the inlet section provides sulfate reducing bacteria that with the sulfuric acid and heavy metals in the solution to form solid metal sulfides. The sulfate reducing bacteria and bacteria nutrient composition is retained in the cells of a honeycomb structure formed of cellular honeycomb panels mounted in the reactor inlet section. The honeycomb panels extend upwardly in the inlet section at an acute angle with respect to the horizontal. The cells defined in each panel are thereby offset with respect to the honeycomb cells in each adjacent panel in order to define a tortuous path for the flow of the aqueous solution.

  7. Coupling between drainage and coarsening in wet foam

    Indian Academy of Sciences (India)

    S Saha; S Bhaumik; A Roy

    2009-06-01

    Drainage and coarsening are two coupled phenomena during the evolution of wet foam. We show the variation in the growth rate of bubble size, along the height in a column of Gillette shaving foam, by microscope imaging. Simultaneously, the drainage of liquid at the same heights has been investigated by Raman spectroscopic measurements. The observations made in these two sets of experiments indicate the coupling between drainage and coarsening in wet foam. We could explain the correlation between our observed data on drainage and coarsening by the empirical relation, proposed by others, in the literature.

  8. Inventory of drainage wells and potential sources of contaminants to drainage-well inflow in Southwest Orlando, Orange County, Florida

    Science.gov (United States)

    Taylor, George Fred

    1993-01-01

    Potential sources of contaminants that could pose a threat to drainage-well inflow and to water in the Floridan aquifer system in southwest Orlando, Florida, were studied between October and December 1990. Drainage wells and public-supply wells were inventoried in a 14-square-mile area, and available data on land use and activities within each drainage well basin were tabulated. Three public-supply wells (tapping the Lower Floridan aquifer) and 38 drainage wells (open to the Upper Floridan aquifer) were located in 17 drainage basins within the study area. The primary sources of drainage-well inflow are lake overflow, street runoff, seepage from the surficial aquifer system, and process-wastewater disposal. Drainage-well inflow from a variety of ares, including resi- dential, commercial, undeveloped, paved, and industrial areas, are potential sources of con- taminants. The four general types of possible contaminants to drainage-well inflow are inorganic chemicals, organic compounds, turbidity, and microbiological contaminants. Potential contami- nant sources include plant nurseries, citrus groves, parking lots, plating companies, auto- motive repair shops, and most commonly, lake- overflow water. Drainage wells provide a pathway for contaminants to enter the Upper Floridan aquifer and there is a potential for contaminants to move downward from the Upper Floridan to the Lower Floridan aquifer.

  9. Black Holes with Skyrme Hair

    CERN Document Server

    Shiiki, N; Shiiki, Noriko; Sawado, Nobuyuki

    2005-01-01

    This paper is intended to give a review of the recent developments on black holes with Skyrme hair. The Einstein-Skyrme system is known to possess black hole solutions with Skyrme hair. The spherically symmetric black hole skyrmion with B=1 was the first discovered counter example of the no-hair conjecture for black holes. Recently we found the B=2 axially symmetric black hole skyrmion. In this system, the black hole at the center of the skyrmion absorbs the baryon number partially, leaving fractional charge outside the horizon. Therefore the baryon number is no longer conserved. We examine the B=1, 2 black hole solutions in detail in this paper. The model has a natural extension to the gauged version which can describe monopole black hole skyrmions. Callan and Witten discussed the monopole catalysis of proton decay within the Skyrme model. We apply the idea to the Einstein-Maxwell-Skyrme system and obtain monopole black hole skyrmions. Remarkably there exist multi-black hole skyrmion solutions in which the g...

  10. Rotating "Black Holes" with Holes in the Horizon

    OpenAIRE

    Burinskii, Alexander; Elizalde, Emilio; Hildebrandt, Sergi R.; Magli, Giulio

    2005-01-01

    Kerr-Schild solutions of the Einstein-Maxwell field equations, containing semi-infinite axial singular lines, are investigated. It is shown that axial singularities break up the black hole, forming holes in the horizon. As a result, a tube-like region appears which allows matter to escape from the interior without crossing the horizon. It is argued that axial singularities of this kind, leading to very narrow beams, can be created in black holes by external electromagnetic or gravitational ex...

  11. Black Holes, Worm Holes, and Future Space Propulsion

    Science.gov (United States)

    Barret, Chris

    2000-01-01

    NASA has begun examining the technologies needed for an Interstellar Mission. In 1998, a NASA Interstellar Mission Workshop was held at the California Institute of Technology to examine the technologies required. Since then, a spectrum of research efforts to support such a mission has been underway, including many advanced and futuristic space propulsion concepts which are being explored. The study of black holes and wormholes may provide some of the breakthrough physics needed to travel to the stars. The first black hole, CYGXI, was discovered in 1972 in the constellation Cygnus X-1. In 1993, a black hole was found in the center of our Milky Way Galaxy. In 1994, the black hole GRO J1655-40 was discovered by the NASA Marshall Space Flight center using the Gamma Ray Observatory. Today, we believe we have found evidence to support the existence of 19 black holes, but our universe may contain several thousands. This paper discusses the dead star states - - both stable and unstable, white dwarfs, neutron stars, pulsars, quasars, the basic features and types of black holes: nonspinning, nonspinning with charge, spinning, and Hawking's mini black holes. The search for black holes, gravitational waves, and Laser Interferometer Gravitational Wave Observatory (LIGO) are reviewed. Finally, concepts of black hole powered space vehicles and wormhole concepts for rapid interstellar travel are discussed in relation to the NASA Interstellar Mission.

  12. Numerical simulation of parallel hole cut blasting with uncharged holes

    Institute of Scientific and Technical Information of China (English)

    Shijie Qu; Xiangbin Zheng; Lihua Fan; Ying Wang

    2008-01-01

    The cavity formation and propagation process of stress wave from parallel hole cut blasting was simulated with AN-SYS/LS-DYNA 3D nonlinear dynamic finite element software. The distribution of element plastic strain, node velocity, node time-acceleration history and the blasting cartridge volume ratio during the process were analyzed. It was found that the detonation of charged holes would cause the interaction of stress wave with the wall of uncharged holes. Initial rock cracking and displacement to neighboring uncharged holes become the main mechanism of cavity formation in early stage.

  13. Structural Holes in Directed Fuzzy Social Networks

    OpenAIRE

    Renjie Hu; Guangyu Zhang

    2014-01-01

    The structural holes have been a key issue in fuzzy social network analysis. For undirected fuzzy social networks where edges are just present or absent undirected fuzzy relation and have no more information attached, many structural holes measures have been presented, such as key fuzzy structural holes, general fuzzy structural holes, strong fuzzy structural holes, and weak fuzzy structural holes. There has been a growing need to design structural holes measures for directed fuzzy social net...

  14. Deep Hole in 'Clovis'

    Science.gov (United States)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1 At a rock called 'Clovis,' the rock abrasion tool on NASA's Mars Exploration Rover Spirit cut a 9-millimeter (0.35-inch) hole during the rover's 216th martian day, or sol (Aug. 11, 2004). The hole is the deepest drilled in a rock on Mars so far. This approximately true-color view was made from images taken by Spirit's panoramic camera on sol 226 (Aug. 21, 2004) at around 12:50 p.m. local true solar time -- early afternoon in Gusev Crater on Mars. To the right is a 'brush flower' of circles produced by scrubbing the surface of the rock with the abrasion tool's wire brush. Scientists used rover's Moessbauer spectrometer and alpha particle X-ray spectrometer to look for iron-bearing minerals and determine the elemental chemical composition of the rock. This composite combines images taken with the camera's 750-, 530-, and 430-nanometer filters. The grayish-blue hue in this image suggests that the interior of the rock contains iron minerals that are less oxidized than minerals on the surface. The diameter of the hole cut into the rock is 4.5 centimeters (1.8 inches). Data on the graph (Figure 1) from the alpha particle X-ray spectrometer instrument on the robotic arm of NASA's Mars Exploration Rover Spirit reveal the elemental chemistry of two rocks, 'Ebenezer' and 'Clovis,' (see PIA06914) in the 'Columbia Hills.' Scientists found, through comparison of the rocks' chemistry, that Ebenezer and Clovis have very different compositions from the rocks on the Gusev plains.

  15. Integrated urban drainage, status and perspectives

    DEFF Research Database (Denmark)

    Harremoës, Poul

    2002-01-01

    with a significant conservatism in the business. However, significant integrated analyses have been reported. Most of them deal with the sewer system and the treatment plant, while few incorporate the receiving water as anything but the object of the loads to be minimised by engineering measures up-stream. Important...... aspects of the papers presented at the INTERURBA-II conference in 2001 and the discussions during the conference. Tools for integrated analysis have been developed, but there is less implementation than could be expected. That is due to lack of adequate knowledge about important mechanisms, coupled......This paper summarises the status of urban storm drainage as an integrated professional discipline, including the management-policy interface, by which the goals of society are implemented. The paper assesses the development of the discipline since the INTERURBA conference in 1992 and includes...

  16. Exact solutions for nonlinear foam drainage equation

    Science.gov (United States)

    Zayed, E. M. E.; Al-Nowehy, Abdul-Ghani

    2017-02-01

    In this paper, the modified simple equation method, the exp-function method, the soliton ansatz method, the Riccati equation expansion method and the ( G^' }/G)-expansion method are used to construct exact solutions with parameters of the nonlinear foam drainage equation. When these parameters are taken to be special values, the solitary wave solutions and the trigonometric function solutions are derived from the exact solutions. The obtained results confirm that the proposed methods are efficient techniques for analytic treatments of a wide variety of nonlinear partial differential equations in mathematical physics. We compare our results together with each other yielding from these integration tools. Also, our results have been compared with the well-known results of others.

  17. Exact solutions for nonlinear foam drainage equation

    Science.gov (United States)

    Zayed, E. M. E.; Al-Nowehy, Abdul-Ghani

    2016-09-01

    In this paper, the modified simple equation method, the exp-function method, the soliton ansatz method, the Riccati equation expansion method and the ( G^' }/G) -expansion method are used to construct exact solutions with parameters of the nonlinear foam drainage equation. When these parameters are taken to be special values, the solitary wave solutions and the trigonometric function solutions are derived from the exact solutions. The obtained results confirm that the proposed methods are efficient techniques for analytic treatments of a wide variety of nonlinear partial differential equations in mathematical physics. We compare our results together with each other yielding from these integration tools. Also, our results have been compared with the well-known results of others.

  18. Geometry of black hole spacetimes

    CERN Document Server

    Andersson, Lars; Blue, Pieter

    2016-01-01

    These notes, based on lectures given at the summer school on Asymptotic Analysis in General Relativity, collect material on the Einstein equations, the geometry of black hole spacetimes, and the analysis of fields on black hole backgrounds. The Kerr model of a rotating black hole in vacuum is expected to be unique and stable. The problem of proving these fundamental facts provides the background for the material presented in these notes. Among the many topics which are relevant for the uniqueness and stability problems are the theory of fields on black hole spacetimes, in particular for gravitational perturbations of the Kerr black hole, and more generally, the study of nonlinear field equations in the presence of trapping. The study of these questions requires tools from several different fields, including Lorentzian geometry, hyperbolic differential equations and spin geometry, which are all relevant to the black hole stability problem.

  19. Urban drainage design and climate change adaptation decision making

    DEFF Research Database (Denmark)

    Zhou, Qianqian

    Since the middle of the 19th century urban drainage has been a vital infrastructure in cities. Traditionally, urban drainage has been used as a convenient cleaning mechanism for public hygiene and an efficient conveyance facility to tackle floods for life and assets protection. From the early 20th...

  20. 49 CFR 192.189 - Vaults: Drainage and waterproofing.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Vaults: Drainage and waterproofing. 192.189 Section 192.189 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... Components § 192.189 Vaults: Drainage and waterproofing. (a) Each vault must be designed so as to...

  1. A synthesis and comparative evaluation of drainage water management

    Science.gov (United States)

    Viable large-scale crop production in the United States requires artificial drainage in humid and poorly drained agricultural regions. Excess water removal is generally achieved by installing tile drains that export water to open ditches that eventually flow into streams. Drainage water management...

  2. 7 CFR 1924.108 - Grading and drainage.

    Science.gov (United States)

    2010-01-01

    .... In questionable or unsurveyed areas, the applicant or developer will provide an engineering report... affect the structure and show proposed solutions. Grading will promote drainage of surface water away from buildings and foundations, minimize earth settlement and erosion, and assure that drainage...

  3. Ecology and management of agricultural drainage ditches: a literature review

    Science.gov (United States)

    Agricultural drainage ditches are headwater streams that have been modified or constructed for agricultural drainage, and are often used in conjunction with tile drains. These modified streams are a common landscape feature in Ohio, and constitute 25% of stream habitat within the state. Management o...

  4. Remediation of Acid Mine Drainage with Sulfate Reducing Bacteria

    Science.gov (United States)

    Hauri, James F.; Schaider, Laurel A.

    2009-01-01

    Sulfate reducing bacteria have been shown to be effective at treating acid mine drainage through sulfide production and subsequent precipitation of metal sulfides. In this laboratory experiment for undergraduate environmental chemistry courses, students design and implement a set of bioreactors to remediate acid mine drainage and explain observed…

  5. Surfing a Black Hole

    Science.gov (United States)

    2002-10-01

    Star Orbiting Massive Milky Way Centre Approaches to within 17 Light-Hours [1] Summary An international team of astronomers [2], lead by researchers at the Max-Planck Institute for Extraterrestrial Physics (MPE) , has directly observed an otherwise normal star orbiting the supermassive black hole at the center of the Milky Way Galaxy. Ten years of painstaking measurements have been crowned by a series of unique images obtained by the Adaptive Optics (AO) NAOS-CONICA (NACO) instrument [3] on the 8.2-m VLT YEPUN telescope at the ESO Paranal Observatory. It turns out that earlier this year the star approached the central Black Hole to within 17 light-hours - only three times the distance between the Sun and planet Pluto - while travelling at no less than 5000 km/sec . Previous measurements of the velocities of stars near the center of the Milky Way and variable X-ray emission from this area have provided the strongest evidence so far of the existence of a central Black Hole in our home galaxy and, implicitly, that the dark mass concentrations seen in many nuclei of other galaxies probably are also supermassive black holes. However, it has not yet been possible to exclude several alternative configurations. In a break-through paper appearing in the research journal Nature on October 17th, 2002, the present team reports their exciting results, including high-resolution images that allow tracing two-thirds of the orbit of a star designated "S2" . It is currently the closest observable star to the compact radio source and massive black hole candidate "SgrA*" ("Sagittarius A") at the very center of the Milky Way. The orbital period is just over 15 years. The new measurements exclude with high confidence that the central dark mass consists of a cluster of unusual stars or elementary particles, and leave little doubt of the presence of a supermassive black hole at the centre of the galaxy in which we live . PR Photo 23a/02 : NACO image of the central region of the Milky Way

  6. Artificial ozone holes

    CERN Document Server

    Dolya, S N

    2014-01-01

    This article considers an opportunity of disinfecting a part of the Earth surface, occupying a large area of ten thousand square kilometers. The sunlight will cause dissociation of molecular bromine into atoms; each bromine atom kills thirty thousand molecules of ozone. Each bromine plate has a mass of forty milligrams grams and destroys ozone in the area of hundred square meters. Thus, to form the ozone hole over the area of ten thousand square kilometers, it is required to have the total mass of bromine equal to the following four tons.

  7. A bottom hole motor

    Energy Technology Data Exchange (ETDEWEB)

    Kibishcher, G.B.; Karpenko, V.K.; Pogorelov, V.P.

    1982-01-01

    A bottom hole motor is proposed which includes a body, a push rod with a piston, a spindle, a mechanism for converting the reciprocal movement of the piston into rotation of the shaft and pump and drain cavities. In order to simplify the design the push rod is made with radial openings above and below the piston, while the shaft is made with two longitudinal channels at the level of the radial openings of the push rod on the diametrically opposite sides. The cavity of one channel is constantly connected with the pump cavity, while the other is permanently connected with the drain cavity.

  8. Thermal BEC Black Holes

    Directory of Open Access Journals (Sweden)

    Roberto Casadio

    2015-10-01

    Full Text Available We review some features of Bose–Einstein condensate (BEC models of black holes obtained by means of the horizon wave function formalism. We consider the Klein–Gordon equation for a toy graviton field coupled to a static matter current in a spherically-symmetric setup. The classical field reproduces the Newtonian potential generated by the matter source, while the corresponding quantum state is given by a coherent superposition of scalar modes with a continuous occupation number. An attractive self-interaction is needed for bound states to form, the case in which one finds that (approximately one mode is allowed, and the system of N bosons can be self-confined in a volume of the size of the Schwarzschild radius. The horizon wave function formalism is then used to show that the radius of such a system corresponds to a proper horizon. The uncertainty in the size of the horizon is related to the typical energy of Hawking modes: it decreases with the increasing of the black hole mass (larger number of gravitons, resulting in agreement with the semiclassical calculations and which does not hold for a single very massive particle. The spectrum of these systems has two components: a discrete ground state of energy m (the bosons forming the black hole and a continuous spectrum with energy ω > m (representing the Hawking radiation and modeled with a Planckian distribution at the expected Hawking temperature. Assuming the main effect of the internal scatterings is the Hawking radiation, the N-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy M = Nm and Entropy 2015, 17 6894 a Planckian distribution for E > M at the same Hawking temperature. This can be used to compute the partition function and to find the usual area law for the entropy, with a logarithmic correction related to the Hawking component. The backreaction of modes with ω > m is also shown to reduce

  9. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bastos, C; Bertolami, O [Departamento de Fisica, Instituto Superior Tecnico, Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal); Dias, N C; Prata, J N, E-mail: cbastos@fisica.ist.utl.p, E-mail: orfeu@cosmos.ist.utl.p, E-mail: ncdias@mail.telepac.p, E-mail: joao.prata@mail.telepac.p [Departamento de Matematica, Universidade Lusofona de Humanidades e Tecnologias, Avenida Campo Grande, 376, 1749-024 Lisboa (Portugal)

    2010-04-01

    One considers phase-space noncommutativity in the context of a Kantowski-Sachs cosmological model to study the interior of a Schwarzschild black hole. It is shown that the potential function of the corresponding quantum cosmology problem has a local minimum. One deduces the thermodynamics and show that the Hawking temperature and entropy exhibit an explicit dependence on the momentum noncommutativity parameter, {eta}. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.

  10. Black hole accretion discs

    OpenAIRE

    Lasota, Jean-Pierre

    2015-01-01

    This is an introduction to models of accretion discs around black holes. After a presentation of the non-relativistic equations describing the structure and evolution of geometrically thin accretion discs we discuss their steady-state solutions and compare them to observation. Next we describe in detail the thermal-viscous disc instability model and its application to dwarf novae for which it was designed and its X-ray irradiated-disc version which explains the soft X--ray transients, i.e. ou...

  11. Artificial black holes

    CERN Document Server

    Visser, Matt; Volovik, Grigory E

    2009-01-01

    Physicists are pondering on the possibility of simulating black holes in the laboratory by means of various "analog models". These analog models, typically based on condensed matter physics, can be used to help us understand general relativity (Einstein's gravity); conversely, abstract techniques developed in general relativity can sometimes be used to help us understand certain aspects of condensed matter physics. This book contains 13 chapters - written by experts in general relativity, particle physics, and condensed matter physics - that explore various aspects of this two-way traffic.

  12. Sulphates Removal from Acid Mine Drainage

    Science.gov (United States)

    Luptáková, Alena; Mačingová, Eva; Kotuličová, Ingrida; Rudzanová, Dominika

    2016-10-01

    Acid mine drainage (AMD) are a worldwide problem leading to ecological destruction in river basins and the contamination of water sources. AMD are characterized by low pH and high content of heavy metals and sulphates. In order to minimize negative impacts of AMD appropriate treatment techniques has to be chosen. Treatment processes are focused on neutralizing, stabilizing and removing pollutants. From this reason efficient and environmental friendly methods are needed to be developed in order to reduce heavy metals as well as sulphates. Various methods are used for remediation of acid mine drainage, but any of them have been applied under commercial-scale conditions. Their application depends on geochemical, technical, natural, financial, and other factors. The aim of the present work was to interpret the study of biological methods for sulphates removal from AMD out-flowing from the shaft Pech of the deposit Smolmk in Slovak Republic. In the experimental works AMD were used after removal of heavy metals by precipitation and sorption using the synthetic sorbent Slovakite. The base of the studied method for the sulphates elimination was the anaerobic bacterial sulphate reduction using sulphate-reducing bacteria (SRB) genera Desulfovibrio. SRB represent a group of bacteria that uses sulphates as a terminal electron acceptor for their metabolism. These bacteria realize the conversion of sulphate to hydrogen sulphide under anaerobic conditions. For the purposes of experiments a few variants of the selective medium DSM-63 culture media were used in term of the sulphates and sodium lactate contents in the selective medium as well as sulphates in the studied AMD.

  13. Conceptual design report for site drainage control

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, M.R.

    1996-07-01

    The Mound Plant (Mound), located in Miamisburg, Ohio, is a Department of Energy (DOE) development and production facility performing support work for DOE`s weapons and energy-related programs. EG&G Mound Applied Technologies, Inc. (EG&G) is the Operating Contractor (OC) for this Government-Owned, Contractor-Operated (GOCO) facility. The work performed at Mound emphasizes nuclear energy and explosives technology. Mound is currently implementing an Environmental, Safety & Health (ES&H) Upgrades Program designed to protect its employees, the public, and the environment from adverse effects caused by facility activities. The first project of this multiphase program is now in the final stages of construction, and the second project is currently under design. Four additional projects, one of which is presented in this report, are in the conceptual design stage. At Mound, 22 soil zones have become contaminated with radioactive material. These zones cover approximately 20 percent of the total area of developed property at the site. During a storm event, the rainwater washes contaminated soil from these zones into the storm sewer system. These radioactive contaminants may then be discharged along with the stormwater into the Great Miami River via the Miami Erie Canal. This conceptual design report (CDR), Site Drainage Control, the fourth project in the ES&H program, describes a project that will provide improvements and much needed repairs to inadequate and deteriorating portions of the storm drainage system on the developed property. The project also will provide a stormwater retention facility capable of storing the stormwater runoff, from the developed property, resulting from a 100-year storm event. These improvements will permit the effective control and monitoring of stormwater to prevent the spread of radioactive contaminants from contaminated soil zones and will provide a means to collect and contain accidental spills of hazardous substances.

  14. Black Holes in Higher Dimensions

    Directory of Open Access Journals (Sweden)

    Reall Harvey S.

    2008-09-01

    Full Text Available We review black-hole solutions of higher-dimensional vacuum gravity and higher-dimensional supergravity theories. The discussion of vacuum gravity is pedagogical, with detailed reviews of Myers–Perry solutions, black rings, and solution-generating techniques. We discuss black-hole solutions of maximal supergravity theories, including black holes in anti-de Sitter space. General results and open problems are discussed throughout.

  15. Origin of supermassive black holes

    OpenAIRE

    Dokuchaev, V. I.; Eroshenko, Yu. N.; Rubin, S G

    2007-01-01

    The origin of supermassive black holes in the galactic nuclei is quite uncertain in spite of extensive set of observational data. We review the known scenarios of galactic and cosmological formation of supermassive black holes. The common drawback of galactic scenarios is a lack of time and shortage of matter supply for building the supermassive black holes in all galaxies by means of accretion and merging. The cosmological scenarios are only fragmentarily developed but propose and pretend to...

  16. Treatment of drainage solution from hydroponic greenhouse production with microalgae.

    Science.gov (United States)

    Hultberg, Malin; Carlsson, Anders S; Gustafsson, Susanne

    2013-05-01

    This study investigated treatment of the drainage solution from greenhouse production with microalgae, through inoculation with Chlorella vulgaris or through growth of the indigenous microalgal community. A significant reduction in nitrogen, between 34.7 and 73.7 mg L(-1), and particularly in phosphorus concentration, between 15.4 and 15.9 mg L(-1), was observed in drainage solution collected from commercial greenhouse production. The large reduction in nutrients was achieved through growth of the indigenous microalgal community i.e., without pre-treatment of the drainage solution or inoculation with the fast growing green microalgae C. vulgaris. Analysis of the fatty acid composition of the algal biomass revealed that compared with a standard growth medium for green algae, the drainage solution was inferior for lipid production. Despite the biorefinery concept being less promising, microalgae-based treatment of drainage solution from greenhouse production is still of interest considering the urgent need for phosphorus recycling.

  17. On the effectiveness of dry drainage in soil salinity control

    Institute of Scientific and Technical Information of China (English)

    WU JingWei; ZHAO LiRong; HUANG JieSheng; YANG JinZhong; VINCENT Bernard; BOUARFA Sami; VIDAL Alain

    2009-01-01

    Dry drainage is thought to be a potential approach to control soil salinity.This study took the Hetao Irrigation District as an example and evaluated the effectiveness of dry drainage by using remote sensing, a conceptual model and a field experiment.Archived remote sensing images from 1973-2006 were used to delineate the temporal and spatial change of soil salinity.The conceptual water and salt balance model was used to evaluate the role of dry drainage in removing excess salt from the irrigated land.The field experiment was performed to get field validation and give more accurate estimation.The results show that dry drainage did contribute to remove excess salt from the irrigated land and succeed in controlling soil salinity in the Hetao Irrigation District.it can be taken as an alternative approach in (semi-)arid area where artificial drainage is not applicable.

  18. On the effectiveness of dry drainage in soil salinity control

    Institute of Scientific and Technical Information of China (English)

    VINCENT; Bernard; BOUARFA; Sami; VIDAL; Alain

    2009-01-01

    Dry drainage is thought to be a potential approach to control soil salinity. This study took the Hetao Irrigation District as an example and evaluated the effectiveness of dry drainage by using remote sensing, a conceptual model and a field experiment. Archived remote sensing images from 1973―2006 were used to delineate the temporal and spatial change of soil salinity. The conceptual water and salt balance model was used to evaluate the role of dry drainage in removing excess salt from the irrigated land. The field experiment was performed to get field validation and give more accurate estimation. The results show that dry drainage did contribute to remove excess salt from the irrigated land and succeed in controlling soil salinity in the Hetao Irrigation District. It can be taken as an alternative approach in (semi-)arid area where artificial drainage is not applicable.

  19. Safety analysis of stability of surface gas drainage boreholes above goaf areas

    Institute of Scientific and Technical Information of China (English)

    LIU Yu-zhou; LI Xiao-hong

    2007-01-01

    As longwall caving mining method prevails rapidly in China coal mines, amount of gas emission from longwall faces and goaf area increased significantly. Using traditional gas drainage methods, such as drilling upward holes to roof strata in tailgate or drilling inseam and cross-measure boreholes, could not meet methane drainage requirements in a gassy mine. The alternative is to drill boreholes from surface down to the longwall goaf area to drain the gas out. As soon as a coal seam is extracted out, the upper rock strata above the goaf start to collapse or become fractured depending upon the rock characteristics and the height above the coal seam. During overlying rock strata being fractured,boreholes in the area may be damaged due to ground movement after the passage of the longwall face. The sudden damage of a borehole may cause a longwall production halt or even a serious mine accident. A theoretical calculation of the stability of surface boreholes in mining affected area is introduced along with an example of determination of borehole and casing diameters is given for demonstration. By using this method for the drilling design, the damage of surface boreholes caused by excessive mining induced displacement can be effectively reduced if not totally avoided. Borehole and casing diameters as well as characteristics of filling materials can be determined using the proposed method by calculating the horizontal movement and vertical stain at different borehole depths.

  20. Can Black Hole Relax Unitarily?

    Science.gov (United States)

    Solodukhin, S. N.

    2005-03-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.

  1. Thermodynamics of Accelerating Black Holes.

    Science.gov (United States)

    Appels, Michael; Gregory, Ruth; Kubizňák, David

    2016-09-23

    We address a long-standing problem of describing the thermodynamics of an accelerating black hole. We derive a standard first law of black hole thermodynamics, with the usual identification of entropy proportional to the area of the event horizon-even though the event horizon contains a conical singularity. This result not only extends the applicability of black hole thermodynamics to realms previously not anticipated, it also opens a possibility for studying novel properties of an important class of exact radiative solutions of Einstein equations describing accelerated objects. We discuss the thermodynamic volume, stability, and phase structure of these black holes.

  2. Black holes and the multiverse

    Science.gov (United States)

    Garriga, Jaume; Vilenkin, Alexander; Zhang, Jun

    2016-02-01

    Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive black holes. The mechanism of black hole formation described in this paper is very generic and has important implications for the global structure of the universe. Baby universes inside super-critical black holes inflate eternally and nucleate bubbles of all vacua allowed by the underlying particle physics. The resulting multiverse has a very non-trivial spacetime structure, with a multitude of eternally inflating regions connected by wormholes. If a black hole population with the predicted mass spectrum is discovered, it could be regarded as evidence for inflation and for the existence of a multiverse.

  3. Can Black Hole Relax Unitarily?

    CERN Document Server

    Solodukhin, S N

    2004-01-01

    We review the way the BTZ black hole relaxes back to thermal equilibrium after a small perturbation and how it is seen in the boundary (finite volume) CFT. The unitarity requires the relaxation to be quasi-periodic. It is preserved in the CFT but is not obvious in the case of the semiclassical black hole the relaxation of which is driven by complex quasi-normal modes. We discuss two ways of modifying the semiclassical black hole geometry to maintain unitarity: the (fractal) brick wall and the worm-hole modification. In the latter case the entropy comes out correctly as well.

  4. How black holes saved relativity

    Science.gov (United States)

    Prescod-Weinstein, Chanda

    2016-02-01

    While there have been many popular-science books on the historical and scientific legacy of Albert Einstein's general theory of relativity, a gap exists in the literature for a definitive, accessible history of the theory's most famous offshoot: black holes. In Black Hole, the science writer Marcia Bartusiak aims for a discursive middle ground, writing solely about black holes at a level suitable for both high-school students and more mature readers while also giving some broader scientific context for black-hole research.

  5. Twistors and Black Holes

    CERN Document Server

    Neitzke, A; Vandoren, S; Neitzke, Andrew; Pioline, Boris; Vandoren, Stefan

    2007-01-01

    Motivated by black hole physics in N=2, D=4 supergravity, we study the geometry of quaternionic-Kahler manifolds M obtained by the c-map construction from projective special Kahler manifolds M_s. Improving on earlier treatments, we compute the Kahler potentials on the twistor space Z and Swann space S in the complex coordinates adapted to the Heisenberg symmetries. The results bear a simple relation to the Hesse potential \\Sigma of the special Kahler manifold M_s, and hence to the Bekenstein-Hawking entropy for BPS black holes. We explicitly construct the ``covariant c-map'' and the ``twistor map'', which relate real coordinates on M x CP^1 (resp. M x R^4/Z_2) to complex coordinates on Z (resp. S). As applications, we solve for the general BPS geodesic motion on M, and provide explicit integral formulae for the quaternionic Penrose transform relating elements of H^1(Z,O(-k)) to massless fields on M annihilated by first or second order differential operators. Finally, we compute the exact radial wave function ...

  6. Transient Black Hole Binaries

    CERN Document Server

    Belloni, T M

    2016-01-01

    The last two decades have seen a great improvement in our understand- ing of the complex phenomenology observed in transient black-hole binary systems, especially thanks to the activity of the Rossi X-Ray Timing Explorer satellite, com- plemented by observations from many other X-ray observatories and ground-based radio, optical and infrared facilities. Accretion alone cannot describe accurately the intricate behavior associated with black-hole transients and it is now clear that the role played by different kinds of (often massive) outflows seen at different phases of the outburst evolution of these systems is as fundamental as the one played by the accretion process itself. The spectral-timing states originally identified in the X-rays and fundamentally based on the observed effect of accretion, have acquired new importance as they now allow to describe within a coherent picture the phenomenology observed at other wave- length, where the effects of ejection processes are most evident. With a particular focu...

  7. Unilobar versus bilobar biliary drainage: effect on quality of life and bilirubin level reduction

    Directory of Open Access Journals (Sweden)

    Shivanand Gamanagatti

    2016-01-01

    Conclusion: Percutaneous biliary drainage provides good palliation of malignant obstructive jaundice. Partial-liver drainage achieved results as good as those after complete liver drainage with significant improvements in QOL and reduction of the bilirubin level.

  8. Designing of the Two-way Suction Drainage Tube in Vacuum Sealing%封闭负压双向引流管的设计

    Institute of Scientific and Technical Information of China (English)

    雷林革; 闫宛春; 陈克明

    2012-01-01

    目的 探讨改良传统VSD的单向负压引流为双向引流,以适应临床治疗的需要,防止堵管.方法 将传统VSD内含的多侧孔引流单向盲管改为双向引流多侧孔管,聚乙烯酒精水化海藻盐泡沫,聚氨酯和丙烯半透性粘贴薄膜与传统VSD相同.结果 采用双向引流多侧孔管VSD可减少堵管几率,并可对复杂感染创面进行对流冲洗,创造生理湿性愈合环境,促进创面愈合.结论 利用改良VSD技术减少了VSD失效几率,提高治疗效果.%Objective To investigate the traditional VSD from one-way improvement to two-way suction drainage, meet the needs of clinical treatment, and prevent bung tube. Methods One-way multi-side hole drainage tube of the traditional VSD was modified for bi-directional mufti-side hole drainage, seaweed salt hydration alcohol polyethylene foam, Semipemneable membrane paste of Polyurethane and acrylic remains the same with that of the traditional VSD. Results The applications of bi-directional multi-side hole drainage pipe can reduce the rate of plugging, rinse the complex and infection wound, create a physiological moist healing environment, and promote wound healing. Conclusions The improved VSD can reduce the failure rate and increase the therapeutic effect.

  9. Black-Hole Mass Measurements

    DEFF Research Database (Denmark)

    Vestergaard, Marianne

    2004-01-01

    The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized.......The applicability and apparent uncertainties of the techniques currently available for measuring or estimating black-hole masses in AGNs are briefly summarized....

  10. Drilling miniature holes, Part III

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, L.K.

    1978-07-01

    Miniature components for precision electromechanical mechanisms such as switches, timers, and actuators typically require a number of small holes. Because of the precision required, the workpiece materials, and the geometry of the parts, most of these holes must be produced by conventional drilling techniques. The use of such techniques is tedious and often requires considerable trial and error to prevent drill breakage, minimize hole mislocation and variations in hole diameter. This study of eight commercial drill designs revealed that printed circuit board drills produced better locational and size repeatability than did other drills when centerdrilling was not used. Boring holes 1 mm in dia, or less, as a general rule did not improve hole location in brass or stainless steel. Hole locations of patterns of 0.66-mm holes can be maintained within 25.4-..mu..m diametral positional tolerance if setup misalignments can be eliminated. Size tolerances of +- 3.8 ..mu..m can be maintained under some conditions when drilling flat plates. While these levels of precision are possible with existing off-the-shelf drills, they may not be practical in many cases.

  11. ATLAS simulated black hole event

    CERN Multimedia

    Pequenão, J

    2008-01-01

    The simulated collision event shown is viewed along the beampipe. The event is one in which a microscopic-black-hole was produced in the collision of two protons (not shown). The microscopic-black-hole decayed immediately into many particles. The colors of the tracks show different types of particles emerging from the collision (at the center).

  12. Nonlinear Electrodynamics and black holes

    CERN Document Server

    Breton, N; Breton, Nora; Garcia-Salcedo, Ricardo

    2007-01-01

    It is addressed the issue of black holes with nonlinear electromagnetic field, focussing mainly in the Born-Infeld case. The main features of these systems are described, for instance, geodesics, energy conditions, thermodynamics and isolated horizon aspects. Also are revised some black hole solutions of alternative nonlinear electrodynamics and its inconveniences.

  13. The cold air drainage model KLAM_21

    Science.gov (United States)

    Kossmann, M.

    2010-09-01

    A brief description of the physics and numerical techniques of the cold air drainage model KLAM_21 is presented. The model has been developed by the Deutscher Wetterdienst (Sievers, 2005) for simulations of nocturnal airflow in hilly and mountainous terrain under dry fair weather conditions. The model has been widely used as an environmental consultancy tool. Typical model applications include frost protection (cold air ponding) and air quality (nocturnal ventilation). The single-layer model calculates the depth and the mean wind of a surface based stable layer that evolves from a neutrally stratified atmosphere during nighttime. The prediction of the velocity and direction of the cold air drainage is based on vertically averaged momentum tendency equations. Temporal changes in the total heat deficit in the cold air layer are calculated from a prescribed local heat loss rate (describing turbulent and radiative cooling) and advection (donor-cell algorithm). The depth of the cold air layer (depth of the surface based temperature inversion) is calculated diagnostically from the total heat loss deficit. The model is initialised with neutral stratification at sunset (onset time of nocturnal cooling). Optionally, effects of an ambient (regional) wind and/or the dispersion of a passive tracer can be simulated. Integration over time is carried out on a regular Arakawa C grid using dynamically calculated time steps. Spatial gradients are discretised using centred differential quotients. The standard size of the computational domains can reach up to 1500 x 1500 grid cells. Grid resolutions usually range between 10 m and 500 m. High resolution simulation can be limited to a nested inner grid domain, while the courser outer domain is covering the entire airshed of interest. A friendly user interface allows easy setup, control, and evaluation of model simulations. Some selected examples of KLAM_21 applications are shown to illustrate the features and capabilities of the model

  14. Technology of gas drainage and utilization in Huaibei mining area

    Institute of Scientific and Technical Information of China (English)

    LI Wei; XU Rui

    2009-01-01

    With the characteristics of coal seam geology and gas occurrence, a "ground-underground" integrated gas drainage method was formed, which can relieve gas pressure and increase permeability by mining the protection seams in conditional regions. After coal seam gas drainage, high gas outburst seam was converted to low gas safety seam. In the coal face mining process, safety and high efficient coal mining were realized by the measure of gas-suction over mining. In addition to the drainage gas for civil gas and gas power generation, the Huaibei Mining Group has actively carried out research on the utilization technology of methane drainage by ventilation. On the one hand, it can save precious energy; on the other hand, it can protect the environment for people's survival. In 2007, the amount of coal mine gas drainage was 120 hm3; the rate of coal mine gas drainage was 44%. Compared with the year 2002, the amount of coal mine gas drainage increased by two times. Meanwhile, the utilization rate of gas increased rapidly.

  15. Comparative experiments of gas drainage in different types of drillings

    Institute of Scientific and Technical Information of China (English)

    LI Cheng-wu; WEI Shan-yang; WANG Chuan; GAO Tian-bao; FU Yu-kai

    2012-01-01

    Gas drainage effect is the utmost important factor for mining speed and mining safety.It has great meaning to study the effect of gas drainage.Comparative experiment of gas drainage in different types of drillings shows that the initial rate of gas natural emission by hydraulic loosed cross drilling is 1.5 times more than that of parallel drilling,and the drilling gas attenuation coefficients reduces to 0.78 times,the effect of gas drainage is good.The ultimate quantity of gas drainage of parallel drilling,cross drilling,hydraulic loosed cross drilling are 859.1,1 323.5 and 1 833.6 m3/100 m.The results of the measurement through these three kinds of drillings of 100 meters drilling is considered as following:cross drilling is 1.54 times more than that of parallel drillings,hydraulic loosed cross drilling are 2.13 times more than parallel drilling.The drainage rate of parallel drilling,cross drilling and hydraulic loosed cross drilling reached 10% to 15% in 3 months with the pre-draining time.Among these,the drainage effect of hydraulic loosed cross drilling increased by 46% than that of parallel drilling in three months.

  16. Systematic review comparing endoscopic, percutaneous and surgical pancreatic pseudocyst drainage

    Institute of Scientific and Technical Information of China (English)

    Anthony Yuen Bun Teoh; Vinay Dhir; Zhen-Dong Jin; Mitsuhiro Kida; Dong Wan Seo; Khek Yu Ho

    2016-01-01

    AIM: To perform a systematic review comparing the outcomes of endoscopic, percutaneous and surgical pancreatic pseudocyst drainage.METHODS: Comparative studies published between January 1980 and May 2014 were identified on Pub Med, Embase and the Cochrane controlled trials register and assessed for suitability of inclusion. The primary outcome was the treatment success rate. Secondary outcomes included were the recurrence rates, re-interventions, length of hospital stay, adverse events and mortalities.RESULTS: Ten comparative studies were identified and 3 were randomized controlled trials. Four studies reported on the outcomes of percutaneous and surgical drainage. Based on a large-scale national study, surgical drainage appeared to reduce mortality and adverse events rate as compared to the percutaneous approach. Three studies reported on the outcomes of endoscopic ultrasound(EUS) and surgical drainage. Clinical success and adverse events rates appeared to be comparable but the EUS approach reduced hospital stay, cost and improved quality of life. Three other studies comparedEUS and esophagogastroduodenoscopy-guided drainage. Both approaches were feasible for pseudocyst drainage but the success rate of the EUS approach was better for non-bulging cyst and the approach conferred additional safety benefits.CONCLUSION: In patients with unfavorable anatomy, surgical cystojejunostomy or percutaneous drainage could be considered. Large randomized studies with current definitions of pseudocysts and longer-term follow-up are needed to assess the efficacy of the various modalities.

  17. Comparison of Methane Drainage Methods Used in Polish Coal Mines

    Science.gov (United States)

    Szlązak, Nikodem; Borowski, Marek; Obracaj, Dariusz; Swolkień, Justyna; Korzec, Marek

    2014-10-01

    Methane drainage is used in Polish coal mines in order to reduce mine methane emissions as well as to keep methane concentration in mine workings at safe levels. This article describes methods of methane drainage during mining used in Polish coal mines. The first method involves drilling boreholes from tailgate roadway to an unstressed zone in roof or floor layers of a mined seam. It is the main method used in Polish mining, where both the location of drilled boreholes as well as their parameters are dependent on mining and ventilation systems of longwalls. The second method is based on drilling overlying drainage galleries in seams situated under or over the mined seam. This article compares these methods with regard to their effectiveness under mining conditions in Polish mines. High effectiveness of methane drainage of longwalls with different ventilation and methane drainage systems has been proven. The highest effectiveness of methane drainage has been observed for the system with overlying drainage gallery and with the parallel tailgate roadways. In case of classic U ventilation system of longwall panel, boreholes drilled from the tailgate roadway behind the longwall front are lost.

  18. Magnetic fields around black holes

    Science.gov (United States)

    Garofalo, David A. G.

    Active Galactic Nuclei are the most powerful long-lived objects in the universe. They are thought to harbor supermassive black holes that range from 1 million solar masses to 1000 times that value and possibly greater. Theory and observation are converging on a model for these objects that involves the conversion of gravitational potential energy of accreting gas to radiation as well as Poynting flux produced by the interaction of the rotating spacetime and the electromagnetic fields originating in the ionized accretion flow. The presence of black holes in astrophysics is taking center stage, with the output from AGN in various forms such as winds and jets influencing the formation and evolution of the host galaxy. This dissertation addresses some of the basic unanswered questions that plague our current understanding of how rotating black holes interact with their surrounding magnetized accretion disks to produce the enormous observed energy. Two magnetic configurations are examined. The first involves magnetic fields connecting the black hole with the inner accretion disk and the other involves large scale magnetic fields threading the disk and the hole. We study the effects of the former type by establishing the consequences that magnetic torques between the black hole and the inner accretion disk have on the energy dissipation profile. We attempt a plausible explanation to the observed "Deep Minimum" state in the Seyfert galaxy MCG-6- 30-15. For the latter type of magnetic geometry, we study the effects of the strength of the magnetic field threading the black hole within the context of the cherished Blandford & Znajek mechanism for black hole spin energy extraction. We begin by addressing the problem in the non-relativistic regime where we find that the black hole-threading magnetic field is stronger for greater disk thickness, larger magnetic Prandtl number, and for a larger accretion disk. We then study the problem in full relativity where we show that our

  19. Fracture evolution and pressure relief gas drainage from distant protected coal seams under an extremely thick key stratum

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; CHENG Yuan-ping; LI Feng-rong; WANG Hai-feng; LIU Hai-bo

    2008-01-01

    When an extremely thick rock bed exists above a protected coal seam in the bending zone given the condition of a mining protective seam, this extremely thick rock bed controls the movement of the entire overlying stratum. This extremely thick rock bed, called a "main key stratum", will not subside nor break for a long time, causing lower fractures and bed separations not to close and gas can migrate to the bed separation areas along the fractures. These bed separations become gas enrichment areas. By analyzing the rule of fracture evolution and gas migration under the main key stratum after the deep protective coal seam has been mined, we propose a new gas drainage method which uses bore holes, drilled through rock and coal seams at great depths for draining pressure relief gas. In this method, the bores are located at a high level suction roadway (we can also drill them in the drilling field located high in an air gateway). Given the practice in the Halzi mine, the gas drainage rate can reach 73% in the middie coal group, with a gas drainage radius over 100 m.

  20. Fear of holes.

    Science.gov (United States)

    Cole, Geoff G; Wilkins, Arnold J

    2013-10-01

    Phobias are usually described as irrational and persistent fears of certain objects or situations, and causes of such fears are difficult to identify. We describe an unusual but common phobia (trypophobia), hitherto unreported in the scientific literature, in which sufferers are averse to images of holes. We performed a spectral analysis on a variety of images that induce trypophobia and found that the stimuli had a spectral composition typically associated with uncomfortable visual images, namely, high-contrast energy at midrange spatial frequencies. Critically, we found that a range of potentially dangerous animals also possess this spectral characteristic. We argue that although sufferers are not conscious of the association, the phobia arises in part because the inducing stimuli share basic visual characteristics with dangerous organisms, characteristics that are low level and easily computed, and therefore facilitate a rapid nonconscious response.

  1. Asymmetric black dyonic holes

    Directory of Open Access Journals (Sweden)

    I. Cabrera-Munguia

    2015-04-01

    Full Text Available A 6-parametric asymptotically flat exact solution, describing a two-body system of asymmetric black dyons, is studied. The system consists of two unequal counterrotating Kerr–Newman black holes, endowed with electric and magnetic charges which are equal but opposite in sign, separated by a massless strut. The Smarr formula is generalized in order to take into account their contribution to the mass. The expressions for the horizon half-length parameters σ1 and σ2, as functions of the Komar parameters and of the coordinate distance, are displayed, and the thermodynamic properties of the two-body system are studied. Furthermore, the seven physical parameters satisfy a simple algebraic relation which can be understood as a dynamical scenario, in which the physical properties of one body are affected by the ones of the other body.

  2. When Charged Black Holes Merge

    Science.gov (United States)

    Kohler, Susanna

    2016-08-01

    Most theoretical models assume that black holes arent charged. But a new study shows that mergers of charged black holes could explain a variety of astrophysical phenomena, from fast radio bursts to gamma-ray bursts.No HairThe black hole no hair theorem states that all black holes can be described by just three things: their mass, their spin, and their charge. Masses and spins have been observed and measured, but weve never measured the charge of a black hole and its widely believed that real black holes dont actually have any charge.That said, weve also never shown that black holes dont have charge, or set any upper limits on the charge that they might have. So lets suppose, for a moment, that its possible for a black hole to be charged. How might that affect what we know about the merger of two black holes? A recent theoretical study by Bing Zhang (University of Nevada, Las Vegas) examines this question.Intensity profile of a fast radio burst, a sudden burst of radio emission that lasts only a few milliseconds. [Swinburne Astronomy Productions]Driving TransientsZhangs work envisions a pair of black holes in a binary system. He argues that if just one of the black holes carries charge possibly retained by a rotating magnetosphere then it may be possible for the system to produce an electromagnetic signal that could accompany gravitational waves, such as a fast radio burst or a gamma-ray burst!In Zhangs model, the inspiral of the two black holes generates a global magnetic dipole thats perpendicular to the plane of the binarys orbit. The magnetic flux increases rapidly as the separation between the black holes decreases, generating an increasingly powerful magnetic wind. This wind, in turn, can give rise to a fast radio burst or a gamma-ray burst, depending on the value of the black holes charge.Artists illustration of a short gamma-ray burst, thought to be caused by the merger of two compact objects. [ESO/A. Roquette]Zhang calculates lower limits on the charge

  3. Kerr black hole thermodynamical fluctuations

    Science.gov (United States)

    Pavon, D.; Rubi, J. M.

    1985-04-01

    The near-equilibrium thermodynamical (TD) fluctuations of a massive rotating uncharged Kerr black hole immersed in a uniformly corotating radiation bath at its temperature are investigated theoretically, generalizing Schwarzschild-black-hole analysis of Pavon and Rubi(1983), based on Einstein fluctuation theory. The correlations for the energy and angular moment fluctuations and the second moments of the other TD parameters are obtained, and the generalized second law of black-hole TD and the Bekenstein (1975) interpretation of black-hole entropy are seen as functioning well in this case. A local-stability criterion and relation for TD equilibrium between the Kerr hole and its own radiation in the flat-space-time limit are derived, and a restriction between C and Lambda is deduced.

  4. Black holes and the multiverse

    CERN Document Server

    Garriga, Jaume; Zhang, Jun

    2015-01-01

    Vacuum bubbles may nucleate and expand during the inflationary epoch in the early universe. After inflation ends, the bubbles quickly dissipate their kinetic energy; they come to rest with respect to the Hubble flow and eventually form black holes. The fate of the bubble itself depends on the resulting black hole mass. If the mass is smaller than a certain critical value, the bubble collapses to a singularity. Otherwise, the bubble interior inflates, forming a baby universe, which is connected to the exterior FRW region by a wormhole. A similar black hole formation mechanism operates for spherical domain walls nucleating during inflation. As an illustrative example, we studied the black hole mass spectrum in the domain wall scenario, assuming that domain walls interact with matter only gravitationally. Our results indicate that, depending on the model parameters, black holes produced in this scenario can have significant astrophysical effects and can even serve as dark matter or as seeds for supermassive blac...

  5. Recoiling Black Holes in Quasars

    CERN Document Server

    Bonning, E W; Salviander, S

    2007-01-01

    Recent simulations of merging black holes with spin give recoil velocities from gravitational radiation up to several thousand km/s. A recoiling supermassive black hole can retain the inner part of its accretion disk, providing fuel for a continuing QSO phase lasting millions of years as the hole moves away from the galactic nucleus. One possible observational manifestation of a recoiling accretion disk is in QSO emission lines shifted in velocity from the host galaxy. We have examined QSOs from the Sloan Digital Sky Survey with broad emission lines substantially shifted relative to the narrow lines. We find no convincing evidence for recoiling black holes carrying accretion disks. We place an upper limit on the incidence of recoiling black holes in QSOs of 4% for kicks greater than 500 km/s and 0.35% for kicks greater than 1000 km/s line-of-sight velocity.

  6. String-Corrected Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Hubeny, Veronika; Maloney, Alexander; Rangamani, Mukund

    2005-02-07

    We investigate the geometry of four dimensional black hole solutions in the presence of stringy higher curvature corrections to the low energy effective action. For certain supersymmetric two charge black holes these corrections drastically alter the causal structure of the solution, converting seemingly pathological null singularities into timelike singularities hidden behind a finite area horizon. We establish, analytically and numerically, that the string-corrected two-charge black hole metric has the same Penrose diagram as the extremal four-charge black hole. The higher derivative terms lead to another dramatic effect -- the gravitational force exerted by a black hole on an inertial observer is no longer purely attractive! The magnitude of this effect is related to the size of the compactification manifold.

  7. Separation of drainage runoff during rainfall-runoff episodes using the stable isotope method and drainage water temperature

    Science.gov (United States)

    Zajíček, Antonín; Kvítek, Tomáš; Pomije, Tomáš

    2014-05-01

    Stabile isotopes of 2H 18O and drainage water temperature were used as natural tracers for separation rainfall-runoff event hydrograph on several tile drained catchments located in Bohemian-Moravian Highland, Czech Republic. Small agricultural catchments with drainage systems built in slopes are typical for foothill areas in the Czech and Moravian highland. Often without permanent surface runoff, the drainage systems represent an important portion of runoff and nitrogen leaching out of the catchment. The knowledge of the drainage runoff formation and the origin of its components are prerequisites for formulation of measures leading to improvement of the drainage water quality and reduction of nutrient leaching from the drained catchments. The results have proved presence of event water in the drainage runoff during rainfall-runoff events. The proportion of event water observed in the drainage runoff varied between 15 - 60 % in the summer events and 0 - 50 % in winter events, while the sudden water temperature change was between 0,1 - 4,2 °C (2 - 35 %). The comparison of isotope separation of the drainage runoff and monitoring the drainage water temperature have demonstrated that in all cases of event water detected in the runoff, a rapid change in the drainage water temperature was observed as well. The portion of event water in the runoff grows with the growing change in water temperature. Using component mixing model, it was demonstrated that water temperature can be successfully used at least as a qualitative and with some degree of inaccuracy as a quantitative tracer as well. The drawback of the non-conservative character of this tracer is compensated by both its economic and technical accessibility. The separation results also resemble results of separations at small streams. Together with a similarly high speed of the discharge reaction to beginning of precipitation, it is obvious that the mechanism of surface runoff formation and drainage runoff formation

  8. Astrophysical Black Holes in the Physical Universe

    CERN Document Server

    Zhang, Shuang-Nan

    2010-01-01

    In this chapter I focus on asking and answering the following questions: (1) What is a black hole? Answer: There are three types of black holes, namely mathematical black holes, physical black holes and astrophysical black holes. An astrophysical black hole, with mass distributed within its event horizon but not concentrated at the singularity point, is not a mathematical black hole. (2) Can astrophysical black holes be formed in the physical universe? Answer: Yes, at least this can be done with gravitational collapse. (3) How can we prove that what we call astrophysical black holes are really black holes? Answer: Finding direct evidence of event horizon is not the way to go. Instead I propose five criteria which meet the highest standard for recognizing new discoveries in experimental physics and observational astronomy. (4) Do we have sufficient evidence to claim the existence of astrophysical black holes in the physical universe? Answer: Yes, astrophysical black holes have been found at least in some galac...

  9. Area spectrum of slowly rotating black holes

    OpenAIRE

    2010-01-01

    We investigate the area spectrum for rotating black holes which are Kerr and BTZ black holes. For slowly rotating black holes, we use the Maggiore's idea combined with Kunstatter's method to derive their area spectra, which are equally spaced.

  10. Black holes in an expanding universe.

    Science.gov (United States)

    Gibbons, Gary W; Maeda, Kei-ichi

    2010-04-02

    An exact solution representing black holes in an expanding universe is found. The black holes are maximally charged and the universe is expanding with arbitrary equation of state (P = w rho with -1 black hole temperature.

  11. Application of digital elevation model in delineating drainage networks

    Institute of Scientific and Technical Information of China (English)

    SUN Yan-ling; XIE De-ti; LIU Hong-bin; WEI Chao-fu

    2005-01-01

    A practical method to extract drainage network from DEM (digital elevation model) is introduced. DEM pretreatment includes depression and flat areas treatment. The flow direction of each grid cell in DEM is calculated according to the 8-direction pour point model, and then the flow accumulation grid from the flow direction grid. With the flow accumulation grid, streams are defined according to the given threshold value of flow accumulation. Taking Gufo River watershed as an example, the extraction of drainage network was done from DEM. The results are basically consistent with the digitized drainage network from the relief maps.

  12. Drainage filters and constructed wetlands to mitigate sitespecific nutrient losses

    DEFF Research Database (Denmark)

    Kjærgaard, Charlotte; Canga, Eriona; Heckrath, Goswin Johann

    2012-01-01

    typically applied to point sources. This calls for a shift of paradigm towards the development of new, cost-efficient technologies to mitigate site-specific nutrient losses in drainage. A newly launched Danish research project “SUPREME-TECH” (2010-2015) (www.supreme-tech.dk) funded by the Danish Strategic...... Research Council, aims at providing the scientific basis for developing cost-effective filter technologies targeting P-retention and N-removal in agricultural subsurface drainage. The project studies different approaches of implementing the filter technologies including drainage well filters as well...

  13. Foam drainage wave coalescing and its energy evolution

    Institute of Scientific and Technical Information of China (English)

    SUN QiCheng; HUANG Jin; WANG GuangQian

    2008-01-01

    Liquid foam is a dense packing of gas bubbles in a small amount of surfactant solution. Liquid drains out of foams until equilibrium is reached due to the compromise between gravity and capillarity, which greatly affects the stability of foam. Based on a series of work on foam structure and drainage we conducted previously, this paper reports the results on coalescence of an original forced drainage wave at a low flow rate with subsequent drainage waves with higher flow rates. The evolutions of vis-cous energy and surface energy during the process of coalescence are theoretically analyzed.

  14. DROUGHT ANALYSIS IN OZANA DRAINAGE BASIN

    Directory of Open Access Journals (Sweden)

    Marina IOSUB

    2016-03-01

    Full Text Available Ozana drainage basin is located at the contact between large landscape units (the Carpathian mountains, the Subcarpathian area, and the plateau region. This placement determines the existence of a complex climate in the region. Despite being small in size, and its extension on an W-E direction, differences can be observed, especially of the way extreme phenomena take place. In the case of droughts, it had different intensities in the mountains, compared to the plateau region. In order to emphasize the different distribution on the territory, several climatic indexes have been calculated, regarding dryness (De Martonne Index, Hellman criterion. The analysis of these indexes at the same monitoring stations (Pluton, Leghin and Dumbrava emphasizes the growth of the drought periods in the plateau region and the fact that they shorten in the mountain area. In the mountainous area, where the land is very well forested, the values of the De Martonne index can reach 45.4, and in the plateau regions, where the forest associations are sparse, the values dropped to 30.6. According to the Hellman criterion, several differences can be emphasized, at basin level. In the mountainous region, there is only one month that, at a multi-annual level, has stood up among the rest, as being excessively droughty, while in the median /central region of the basin, three months have been identified, that have such potential, as well as five months, at Dumbrava.

  15. Investigation of Spiral and Sweeping Holes

    Science.gov (United States)

    Thurman, Douglas; Poinsatte, Philip; Ameri, Ali; Culley, Dennis; Raghu, Surya; Shyam, Vikram

    2015-01-01

    Surface infrared thermography, hotwire anemometry, and thermocouple surveys were performed on two new film cooling hole geometries: spiral/rifled holes and fluidic sweeping holes. The spiral holes attempt to induce large-scale vorticity to the film cooling jet as it exits the hole to prevent the formation of the kidney shaped vortices commonly associated with film cooling jets. The fluidic sweeping hole uses a passive in-hole geometry to induce jet sweeping at frequencies that scale with blowing ratios. The spiral hole performance is compared to that of round holes with and without compound angles. The fluidic hole is of the diffusion class of holes and is therefore compared to a 777 hole and Square holes. A patent-pending spiral hole design showed the highest potential of the non-diffusion type hole configurations. Velocity contours and flow temperature were acquired at discreet cross-sections of the downstream flow field. The passive fluidic sweeping hole shows the most uniform cooling distribution but suffers from low span-averaged effectiveness levels due to enhanced mixing. The data was taken at a Reynolds number of 11,000 based on hole diameter and freestream velocity. Infrared thermography was taken for blowing rations of 1.0, 1.5, 2.0, and 2.5 at a density ration of 1.05. The flow inside the fluidic sweeping hole was studied using 3D unsteady RANS.

  16. Bibliography for acid-rock drainage and selected acid-mine drainage issues related to acid-rock drainage from transportation activities

    Science.gov (United States)

    Bradley, Michael W.; Worland, Scott C.

    2015-01-01

    Acid-rock drainage occurs through the interaction of rainfall on pyrite-bearing formations. When pyrite (FeS2) is exposed to oxygen and water in mine workings or roadcuts, the mineral decomposes and sulfur may react to form sulfuric acid, which often results in environmental problems and potential damage to the transportation infrastructure. The accelerated oxidation of pyrite and other sulfidic minerals generates low pH water with potentially high concentrations of trace metals. Much attention has been given to contamination arising from acid mine drainage, but studies related to acid-rock drainage from road construction are relatively limited. The U.S. Geological Survey, in cooperation with the Tennessee Department of Transportation, is conducting an investigation to evaluate the occurrence and processes controlling acid-rock drainage and contaminant transport from roadcuts in Tennessee. The basic components of acid-rock drainage resulting from transportation activities are described and a bibliography, organized by relevant categories (remediation, geochemical, microbial, biological impact, and secondary mineralization) is presented.

  17. Black Holes: The Membrane Viewpoint

    Science.gov (United States)

    Thorne, Kip S.

    Contents: I. Introduction: 1. Overview of the membrane viewpoint. 2. History of research on the membrane viewpoint. II. The 3+1 split of spacetime: 1. ZAMOs and the 3+1 split of the metric. 2. Gravitoelectric and gravitomagnetic fields. 3. 3+1 split of electrodynamics. III. Stretching the horizon and black-hole thermodynamics: 1. Macdonald's vibrating magnetic field problem. 2. Stretching the horizon. 3. The entropy of a black hole. 4. The thermodynamics and mechanics of a black hole. IV. Electrodynamics of the stretched horizon: 1. The laws of Gauss, Ampere, Ohm, and charge conservation. 2. Lorentz force and ohmic dissipation in the stretched horizon. V. Some electromagnetic model problems: 1. Charge separation in the stretched horizon. 2. Black hole as a resistor in an electric circuit. 3. Black hole as the rotor in an electric motor. 4. Rotating hole immersed in a time-independent, vacuum magnetic field. 5. Magnetized, rotating hole as a battery for an external circuit. VI. Astrophysical applications of the membrane formalism. VII. Conclusion.

  18. A nonsingular rotating black hole

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematical Sciences, Durban (South Africa)

    2015-11-15

    The spacetime singularities in classical general relativity are inevitable, as predicated by the celebrated singularity theorems. However, it is a general belief that singularities do not exist in Nature and that they are the limitations of the general relativity. In the absence of a welldefined quantum gravity, models of regular black holes have been studied. We employ a probability distribution inspired mass function m(r) to replace the Kerr black hole mass M to represent a nonsingular rotating black hole that is identified asymptotically (r >> k, k > 0 constant) exactly as the Kerr-Newman black hole, and as the Kerr black hole when k = 0. The radiating counterpart renders a nonsingular generalization of Carmeli's spacetime as well as Vaidya's spacetime, in the appropriate limits. The exponential correction factor changing the geometry of the classical black hole to remove the curvature singularity can also be motivated by quantum arguments. The regular rotating spacetime can also be understood as a black hole of general relativity coupled to nonlinear electrodynamics. (orig.)

  19. Rotating black hole and quintessence

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Sushant G. [Jamia Millia Islamia, Centre for Theoretical Physics, New Delhi (India); University of KwaZulu-Natal, Astrophysics and Cosmology Research Unit, School of Mathematics, Statistics and Computer Science, Private Bag 54001, Durban (South Africa)

    2016-04-15

    We discuss spherically symmetric exact solutions of the Einstein equations for quintessential matter surrounding a black hole, which has an additional parameter (ω) due to the quintessential matter, apart from the mass (M). In turn, we employ the Newman-Janis complex transformation to this spherical quintessence black hole solution and present a rotating counterpart that is identified, for α = -e{sup 2} ≠ 0 and ω = 1/3, exactly as the Kerr-Newman black hole, and as the Kerr black hole when α = 0. Interestingly, for a given value of parameter ω, there exists a critical rotation parameter (a = a{sub E}), which corresponds to an extremal black hole with degenerate horizons, while for a < a{sub E}, it describes a nonextremal black hole with Cauchy and event horizons, and no black hole for a > a{sub E}. We find that the extremal value a{sub E} is also influenced by the parameter ω and so is the ergoregion. (orig.)

  20. Cosmic Intelligence and Black Holes

    CERN Document Server

    Lefebvre, V A; Lefebvre, Vladimir A.; Efremov, Yuri N.

    2000-01-01

    The paper is devoted to a new direction in SETI. After a general discussion of the field, the authors put forth the hypothesis that the black holes may serve as a physical substratum for intelligent beings. This hypothesis is based on four parallels between the brain-psyche system, on the one hand, and black holes, on the other. (1) The descriptions of brain and psyche, in the system brain-psyche, are complementary to each other, as descriptions by internal and external observers of a black hole in Susskind-t'Hooft's schema. (2) There is an aspect of the inner structure of a black hole in Kerr's model of the rotating black hole that is isomorphic to the structure of the human subjective domain in the psychological model of reflexion. (3) Both black holes and the brain-psyche system have a facet which can be represented using thermodynamic concepts. (4) The brain lends itself to a holographic description; as has been recently demonstrated by Susskind, black holes can also be described holographically. The auth...

  1. Superconducting electron and hole lenses

    Science.gov (United States)

    Cheraghchi, H.; Esmailzadeh, H.; Moghaddam, A. G.

    2016-06-01

    We show how a superconducting region (S), sandwiched between two normal leads (N), in the presence of barriers, can act as a lens for propagating electron and hole waves by virtue of the so-called crossed Andreev reflection (CAR). The CAR process, which is equivalent to Cooper pair splitting into two N electrodes, provides a unique possibility of constructing entangled electrons in solid state systems. When electrons are locally injected from an N lead, due to the CAR and normal reflection of quasiparticles by the insulating barriers at the interfaces, sequences of electron and hole focuses are established inside another N electrode. This behavior originates from the change of momentum during electron-hole conversion beside the successive normal reflections of electrons and holes due to the barriers. The focusing phenomena studied here are fundamentally different from the electron focusing in other systems, such as graphene p-n junctions. In particular, due to the electron-hole symmetry of the superconducting state, the focusing of electrons and holes is robust against thermal excitations. Furthermore, the effects of the superconducting layer width, the injection point position, and barrier strength are investigated on the focusing behavior of the junction. Very intriguingly, it is shown that by varying the barrier strength, one can separately control the density of electrons or holes at the focuses.

  2. Adaptive Drainage Slots for Acoustic Noise Attenuation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG), proposes to demonstrate feasibility in the reduction of noise attributed to drainage slots in jet engine acoustic liners....

  3. Gravity Drainage of Activated Sludge on Reed Beds

    DEFF Research Database (Denmark)

    Christensen, Morten Lykkegaard; Dominiak, Dominik Marek; Keiding, Kristian;

    Activated sludge is a by-product from waste water treatment plants, and the water content in the sludge is high (> 90%). Among several methods to remove the water, sludge drying reed beds are often used to dewater the sludge by drainage. There is, however, no well-defined criterion for design...... has therefore been developed to measure relevant quality parameters: specific cake resistance, settling velocity and cake compressibility. It has been found that activated sludge form highly compressible cake even at the low compressive pressures obtained during drainage. Numerical simulation shows...... that the compressibility has a high influence on the drainage process especially during the start-up phases where the volumetric load on the sludge bed is critical. The load has to be low in order to ensure that the drainage properties of the bed are not destroyed. The data also shows that transport of activated sludge...

  4. Fall 1979 moose surveys, Sheenjek, Old Woman, Coleen drainages

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Summary of fall moose population statistics for the upper Sheenjek River drainage (including all tributaries upstream of Lobo Lake) and of Old Woman Creek. William...

  5. Drainage report for Delair Division of Great River NWR

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Obstacles such as ground seepage, inefficient water control structures, and backwater in the Sny Ditch are all contributing to drainage problems at the Delair...

  6. Monitoring and remediation technologies of organochlorine pesticides in drainage water

    Directory of Open Access Journals (Sweden)

    Ismail Ahmed

    2015-03-01

    Full Text Available This study was carried out to monitor the presence of organochlorine in drainage water in Kafr-El-Sheikh Governorate, Egypt. Furthermore, to evaluate the efficiencies of different remediation techniques (advanced oxidation processes [AOPs] and bioremediation for removing the most frequently detected compound (lindane in drainage water. The results showed the presence of several organochlorine pesticides in all sampling sites. Lindane was detected with high frequency relative to other detected organochlorine in drainage water. Nano photo-Fenton like reagent was the most effective treatment for lindane removal in drainage water. Bioremediation of lindane by effective microorganisms (EMs removed 100% of the lindane initial concentration. There is no remaining toxicity in lindane contaminated-water after remediation on treated rats relative to control with respect to histopathological changes in liver and kidney. Advanced oxidation processes especially with nanomaterials and bioremediation using effective microorganisms can be regarded as safe and effective remediation technologies of lindane in water.

  7. 1986 moose census, lower Nowitna River drainage: Final report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — A moose survey of the lower Nowitna drainage on the Nowitna National Wildlife Refuge was conducted from 17-21 November 1986. The 1986 population estimate for the...

  8. Recycling Facilities - Mine Drainage Treatment/Land Recycling Project Locations

    Data.gov (United States)

    NSGIC GIS Inventory (aka Ramona) — Mine Drainage Treatment/Land Reclamation Locations are clean-up projects that are working to eliminate some form of abandoned mine. The following sub-facility types...

  9. Adaptive Drainage Slots for Acoustic Noise Attenuation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cornerstone Research Group, Inc. (CRG) demonstrated feasibility in the reduction of noise attributed to drainage slots in jet engine acoustic liners. This was...

  10. Shallow Melting and Underground Drainage in Utopia Planitia, Mars

    Science.gov (United States)

    Costard, F.; Sejourne, A.; Kargel, J.; Soare, R.

    2012-03-01

    Based on the identification of sinuous and elongated pits in Utopia Planitia, we suggest that shallow melting and underground drainage are possible. We test that hypothesis using a thermal model that comprises a thick insulating dusty layer.

  11. Mercury mine drainage and processes that control its environmental impact

    Science.gov (United States)

    Rytuba, J.J.

    2000-01-01

    Mine drainage from mercury mines in the California Coast Range mercury mineral belt is an environmental concern because of its acidity and high sulfate, mercury, and methylmercury concentrations. Two types of mercury deposits are present in the mineral belt, silica-carbonate and hot-spring type. Mine drainage is associated with both deposit types but more commonly with the silica-carbonate type because of the extensive underground workings present at these mines. Mercury ores consisting primarily of cinnabar were processed in rotary furnaces and retorts and elemental mercury recovered from condensing systems. During the roasting process mercury phases more soluble than cinnabar are formed and concentrated in the mine tailings, commonly termed calcines. Differences in mineralogy and trace metal geochemistry between the two deposit types are reflected in mine drainage composition. Silica-carbonate type deposits have higher iron sulfide content than hot- spring type deposits and mine drainage from these deposits may have extreme acidity and very high concentrations of iron and sulfate. Mercury and methylmercury concentrations in mine drainage are relatively low at the point of discharge from mine workings. The concentration of both mercury species increases significantly in mine drainage that flows through and reacts with calcines. The soluble mercury phases in the calcines are dissolved and sulfate is added such that methylation of mercury by sulfate reducing bacteria is enhanced in calcines that are saturated with mine drainage. Where mercury mine drainage enters and first mixes with stream water, the addition of high concentrations of mercury and sulfate generates a favorable environment for methylation of mercury. Mixing of oxygenated stream water with mine drainage causes oxidation of dissolved iron(II) and precipitation of iron oxyhydroxide that accumulates in the streambed. Both mercury and methylmercury are strongly adsorbed onto iron oxyhydroxide over the p

  12. Unveiling the edge of time black holes, white holes, wormholes

    CERN Document Server

    Gribbin, John

    1992-01-01

    Acclaimed science writer John Gribbin recounts dramatic stories that have led scientists to believe black holes and their more mysterious kin are not only real, but might actually provide a passage to other universes and travel through time.

  13. Quantum mechanics of black holes.

    Science.gov (United States)

    Witten, Edward

    2012-08-03

    The popular conception of black holes reflects the behavior of the massive black holes found by astronomers and described by classical general relativity. These objects swallow up whatever comes near and emit nothing. Physicists who have tried to understand the behavior of black holes from a quantum mechanical point of view, however, have arrived at quite a different picture. The difference is analogous to the difference between thermodynamics and statistical mechanics. The thermodynamic description is a good approximation for a macroscopic system, but statistical mechanics describes what one will see if one looks more closely.

  14. Orbital resonances around black holes.

    Science.gov (United States)

    Brink, Jeandrew; Geyer, Marisa; Hinderer, Tanja

    2015-02-27

    We compute the length and time scales associated with resonant orbits around Kerr black holes for all orbital and spin parameters. Resonance-induced effects are potentially observable when the Event Horizon Telescope resolves the inner structure of Sgr A*, when space-based gravitational wave detectors record phase shifts in the waveform during the resonant passage of a compact object spiraling into the black hole, or in the frequencies of quasiperiodic oscillations for accreting black holes. The onset of geodesic chaos for non-Kerr spacetimes should occur at the resonance locations quantified here.

  15. Black holes and Higgs stability

    Energy Technology Data Exchange (ETDEWEB)

    Tetradis, Nikolaos [Department of Physics, University of Athens,Zographou 157 84 (Greece); Physics Department, Theory Unit, CERN,CH-1211 Geneva 23 (Switzerland)

    2016-09-20

    We study the effect of primordial black holes on the classical rate of nucleation of AdS regions within the standard electroweak vacuum. We find that the energy barrier for transitions to the new vacuum, which characterizes the exponential suppression of the nucleation rate, can be reduced significantly in the black-hole background. A precise analysis is required in order to determine whether the the existence of primordial black holes is compatible with the form of the Higgs potential at high temperature or density in the Standard Model or its extensions.

  16. The Black Hole Information Problem

    CERN Document Server

    Polchinski, Joseph

    2016-01-01

    The black hole information problem has been a challenge since Hawking's original 1975 paper. It led to the discovery of AdS/CFT, which gave a partial resolution of the paradox. However, recent developments, in particular the firewall puzzle, show that there is much that we do not understand. I review the black hole, Hawking radiation, and the Page curve, and the classic form of the paradox. I discuss AdS/CFT as a partial resolution. I then discuss black hole complementarity and its limitations, leading to many proposals for different kinds of `drama.' I conclude with some recent ideas.

  17. Static-Fluid Black Holes

    CERN Document Server

    Cho, Inyong

    2016-01-01

    We investigate black holes formed by static perfect fluid with $p=-\\rho/3$. These represent the black holes in $S_3$ and $H_3$ spatial geometries. There are three classes of black-hole solutions, two $S_3$ types and one $H_3$ type. The interesting solution is the one of $S_3$ type which possesses two singularities. The one is at the north pole behind the horizon, and the other is naked at the south pole. The observers, however, are free from falling to the naked singularity. There are also nonstatic cosmological solutions in $S_3$ and $H_3$, and a singular static solution in $H_3$.

  18. On regular rotating black holes

    Science.gov (United States)

    Torres, R.; Fayos, F.

    2017-01-01

    Different proposals for regular rotating black hole spacetimes have appeared recently in the literature. However, a rigorous analysis and proof of the regularity of this kind of spacetimes is still lacking. In this note we analyze rotating Kerr-like black hole spacetimes and find the necessary and sufficient conditions for the regularity of all their second order scalar invariants polynomial in the Riemann tensor. We also show that the regularity is linked to a violation of the weak energy conditions around the core of the rotating black hole.

  19. Black Holes: A Traveler's Guide

    Science.gov (United States)

    Pickover, Clifford A.

    1998-03-01

    BLACK HOLES A TRAVELER'S GUIDE Clifford Pickover's inventive and entertaining excursion beyond the curves of space and time. "I've enjoyed Clifford Pickover's earlier books . . . now he has ventured into the exploration of black holes. All would-be tourists are strongly advised to read his traveler's guide." -Arthur C. Clarke. "Many books have been written about black holes, but none surpass this one in arousing emotions of awe and wonder towards the mysterious structure of the universe." -Martin Gardner. "Bucky Fuller thought big. Arthur C. Clarke thinks big, but Cliff Pickover outdoes them both." -Wired. "The book is fun, zany, in-your-face, and refreshingly addictive." -Times Higher Education Supplement.

  20. Abdominal drainage following cholecystectomy: high, low, or no suction?

    OpenAIRE

    McCormack, T T; Abel, P D; Collins, C. D.

    1983-01-01

    A prospective trial to assess the effect of suction in an abdominal drain following cholecystectomy was carried out. Three types of closed drainage system were compared: a simple tube drain, a low negative pressure drain, and a high negative pressure drain: 120 consecutive patients undergoing cholecystectomy were randomly allocated to one of the three drainage groups. There was no significant difference in postoperative pyrexia, wound infection, chest infection, or hospital stay. This study f...

  1. Effects of drainage salinity evolution on irrigation management

    Science.gov (United States)

    Kan, Iddo

    2003-12-01

    A soil physics theory of solute movement through a drained saturated zone underlying agricultural land is introduced into a long-term economic analysis of farm-level irrigation management; this is an alternative to the immediate, homogeneous blending assumption employed in previous studies as a base for calculating changes in drainage salinity over time. Using data from California, the effect of drainage salinity evolution is analyzed through a year-by-year profit optimization under the requirement of on-farm drainage disposal. Paths of optimal land allocation among crop production with fresh surface water, saline drainage reuse and evaporation ponds appear to depend on the relative profitability of the first two; that of reuse is affected by the trend of drainage salinity. Tile spacing and environmental regulations associated with evaporation ponds affect the timing of evaporation pond construction. The system converges into a solution involving both drainage-disposal activities; this solution includes an outlet for salts and is therefore sustainable. Following this strategy, the system is asymptotically approaching a steady state that possesses both hydrological and salt balances. Economic implications associated with land retirement programs in California are discussed.

  2. Percutaneous transhepatic biliary drainage: analysis of 175 cases

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kyung Jin; Lee, Sang Kwon; Kim, Tae Hun; Kim, Yong Joo; Kang, Duk Sik [College of Medicine, Kyungpook National Univ., Daegu (Korea, Republic of)

    1990-10-15

    Percutaneous transhepatic biliary drainage is a safe, effective and palliative means of treatment in biliary obstruction, especially in cases with malignant obstruction which are inoperable. 175 cases of transhepatic biliary drainage were performed on 119 patients with biliary obstruction from January 1985 to June 1989 at Kyung-pook National University Hospital. The causes of obstructive jaundice were 110 malignant diseases and 9 benign diseases. The most common indication for drainage was palliative intervention of obstruction secondary to malignant tumor in 89 cases. 86 cases of external drainage were performed including 3 cases of left duct approach, 29 cases of external-internal drainage and 60 cases of endoprosthesis. In external and external-internal drainages, immediate major complications (11.9%) occurred, including not restricted to, but sepsis, bile peritonitis and hemobilia. Delayed major complications (42.9%) were mainly catheter related. The delayed major complication of endoprosthesis resulted from obstruction of the internal stent. The mean time period to reobstruction of the internal stent was about 12 weeks. To improve management status, regular follow-up is required, as is education of both patients and their families as to when immediate clinical attention is mandated. Close communication amongst the varying medical specialities involved will be necessary to provide optional treatment for each patient.

  3. Percutaneous catheter drainage of intraabdominal abscesses and fluid

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Tae; Kwon, Tae Hee; Yoo, Hyung Sik; Suh, Jung Ho [Yonsei University College of Medicine, Seoul (Korea, Republic of); Lee, Young Ho [Cheil General Hospital, Seoul (Korea, Republic of)

    1986-10-15

    Percutaneous catheter drainage has been reported to be an effective method in the management of selected patients with abscess and fluid collection. Its high success rate and relatively low complications make the procedure an alternative to surgery in the individual cases. During past two years percutaneous catheter drainage in 25 patients with intraabdominal abscesses and fluid collection was performed at the Department of Radiology, Yonsei University College of medicine. Here the technique and author's results were summarized. 1. The total 25 patients who had percutaneous catheter drainage are 10 liver abscesses, 3 subphrenic, one subhepatic, 4 renal and perirenal, 2 pelvic, one psoas, one anterior pararenal fluid from acute pancreatitis, one pancreas pseudocyst and 2 malignant tumor necrosis. 2. The modified Seldinger technique used for all cases of abscess and fluid drainage under guidance of ultrasound scan. The used catheters were 10F. Pigtail and 14F. Malecot (Cook c/o) catheters. 3. The abscesses and fluid of 17 patients among 25 were cured by the percutaneous catheter drainage and 4 patients were clinically improved. The catheter drainage was failed in 2 patients and 3 complication were developed. 4. The success rate of this procedure was 91.3%, failure rate was 8.7% and complication rate was 12%.

  4. Extrude Hone deburring with X-base media

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, L.K.

    1973-09-01

    Small precision mechanisms must have burr-free, sharp-edged parts to operate well. Controlling the size of burrs can lower burr removal costs and improve edge repeatability. Study results indicated that with conventional tooling approaches, Extrude Hone deburring with x-base media removes more material from the hole than desired and is less repeatable than required on precision miniature parts. With this media, the process is most applicable to precision miniature parts with burrs less than 25.4 ..mu..m thick, allowable hole size changes equal to burr thickness, and allowable hole size repeatability of +-0.2 times the actual average hole size change.

  5. Black hole meiosis

    Science.gov (United States)

    van Herck, Walter; Wyder, Thomas

    2010-04-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, [1]. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the ‘chromosomes’ of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as ‘crossing-over in the meiosis of a D-particle’. Our results improve on [2], provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity for refinement results from the fact that tachyonic strings split up constituent states into ‘generic’ and ‘special’ states. These are enumerated separately by topological invariants, which turn out to be partitions of Donaldson-Thomas invariants. As modular predictions provide a check on many of our results, we have compelling evidence that our computations are correct.

  6. Black Hole Meiosis

    CERN Document Server

    Van Herck, Walter

    2009-01-01

    The enumeration of BPS bound states in string theory needs refinement. Studying partition functions of particles made from D-branes wrapped on algebraic Calabi-Yau 3-folds, and classifying states using split attractor flow trees, we extend the method for computing a refined BPS index, arXiv:0810.4301. For certain D-particles, a finite number of microstates, namely polar states, exclusively realized as bound states, determine an entire partition function (elliptic genus). This underlines their crucial importance: one might call them the `chromosomes' of a D-particle or a black hole. As polar states also can be affected by our refinement, previous predictions on elliptic genera are modified. This can be metaphorically interpreted as `crossing-over in the meiosis of a D-particle'. Our results improve on hep-th/0702012, provide non-trivial evidence for a strong split attractor flow tree conjecture, and thus suggest that we indeed exhaust the BPS spectrum. In the D-brane description of a bound state, the necessity...

  7. How Black Holes Burn

    CERN Document Server

    Brustein, Ram

    2014-01-01

    We present a calculation of the rate of information release from a Schwarzschild BH. We have recently extended Hawking's theory of black hole (BH) evaporation to account for quantum fluctuations of the background geometry, as well as for back-reaction and time-dependence effects. Our main result has been a two-point function matrix for the radiation that consists of Hawking's thermal matrix plus off-diagonal corrections that are initially small and become more important as the evaporation proceeds. Here, we show that, if the phases and amplitudes of the radiation matrix are recorded over the lifetime of the BH, then the radiation purifies in a continuous way. We conjecture that our results establish the maximal rate at which information can be released from a semiclassical BH, to be contrasted with the minimal rate that was predicted by Page on the basis of generic unitarity arguments. When the phases of the radiation matrix are not tracked, we show that it purifies only parametrically close to the end of the...

  8. Borehole cylindrical noise during hole-surface and hole-hole resistivity measurements

    Science.gov (United States)

    Osiensky, James L.; Nimmer, Robin; Binley, Andrew M.

    2004-04-01

    Drilled boreholes generally are the only feasible means to access the subsurface for the emplacement of downhole electrodes for most hole-hole and hole-surface resistivity experiments. However, the very existence of the borehole itself creates the potential for significant noise due to the inevitable conductivity contrast that develops between the borehole walls and the formation. Borehole cylindrical noise develops whenever a current source is placed in a drilled borehole. Borehole geometries may range from nearly perfect cylinders to highly, irregular, rugose holes in consolidated rock, to relatively minor, collapsed, disturbed zones in caving sediments. Boreholes in non-caving formations generally are filled with artificial, conductive materials to afford crucial, electrical continuity between downhole electrodes and the borehole walls. Filled boreholes form cylindrically shaped heterogeneities that create significant noise due to preferential current flow up and down the conductive columns. Selected conditions are simulated with a finite difference model to illustrate the significance of borehole cylindrical noise on hole-hole and hole-surface mise-à-la-masse electrical potentials near a current electrode. Mise-à-la-masse electrical potentials measured during a field tracer experiment also are presented. These measurements are used to illustrate significant errors may develop in the interpretation of apparent resistivity estimates out to a distance of several meters from the current source if borehole cylindrical noise is not recognized and accounted for in the analysis of electrical potential data.

  9. Black hole information vs. locality

    CERN Document Server

    Itzhaki, N

    1996-01-01

    We discuss the limitations on space time measurement in Schwarzchild metric. We find that near the horizon the limitations on space time measurement are of the order of the black hole radius. We suggest that it indicates that a large mass black hole can not be described by means of local field theory even at macroscopic distances and that any attempt to describe black hole formation and evaporation by means of an effective local field theory will necessarily lead to information loss. We also present a new interpretation of the black hole entropy which leads to S=cA , where c is a constant of order 1 which does not depend on the number of fields.

  10. 'Black holes': escaping the void.

    Science.gov (United States)

    Waldron, Sharn

    2013-02-01

    The 'black hole' is a metaphor for a reality in the psyche of many individuals who have experienced complex trauma in infancy and early childhood. The 'black hole' has been created by an absence of the object, the (m)other, so there is no internalized object, no (m)other in the psyche. Rather, there is a 'black hole' where the object should be, but the infant is drawn to it, trapped by it because of an intrinsic, instinctive need for a 'real object', an internalized (m)other. Without this, the infant cannot develop. It is only the presence of a real object that can generate the essential gravity necessary to draw the core of the self that is still in an undeveloped state from deep within the abyss. It is the moving towards a real object, a (m)other, that relativizes the absolute power of the black hole and begins a reformation of its essence within the psyche.

  11. Formation of Supermassive Black Holes

    CERN Document Server

    Volonteri, Marta

    2010-01-01

    Evidence shows that massive black holes reside in most local galaxies. Studies have also established a number of relations between the MBH mass and properties of the host galaxy such as bulge mass and velocity dispersion. These results suggest that central MBHs, while much less massive than the host (~ 0.1%), are linked to the evolution of galactic structure. In hierarchical cosmologies, a single big galaxy today can be traced back to the stage when it was split up in hundreds of smaller components. Did MBH seeds form with the same efficiency in small proto-galaxies, or did their formation had to await the buildup of substantial galaxies with deeper potential wells? I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I will discuss black hole formation processes for `seed' black holes that are likely to place at early cosmic epochs, and possible observational tests of these scenarios.

  12. Black holes and quantum mechanics

    Energy Technology Data Exchange (ETDEWEB)

    Hooft, G. ' t, E-mail: g.thooft@uu.n [Institute for Theoretical Physics, Utrecht University and Spinoza Institute, P.O. Box 80.195, 3508 TD Utrecht (Netherlands)

    2010-07-15

    After a brief review of quantum black hole physics, it is shown how the dynamical properties of a quantum black hole may be deduced to a large extent from Standard Model Physics, extended to scales near the Planck length, and combined with results from perturbative quantum gravity. Together, these interactions generate a Hilbert space of states on the black hole horizon, which can be investigated, displaying interesting systematics by themselves. To make such approaches more powerful, a study is made of the black hole complementarity principle, from which one may deduce the existence of a hidden form of local conformal invariance. Finally, the question is raised whether the principles underlying Quantum Mechanics are to be sharpened in this domain of physics as well. There are intriguing possibilities.

  13. Singularities Inside Hairy Black Holes

    OpenAIRE

    Gal'tsov, D. V.; Donets, E. E.; Zotov, M. Yu.

    1997-01-01

    We show that the Strong Cosmic Censorship is supported by the behavior of generic solutions on the class of static spherically symmetric black holes in gravitating gauge models and their stringy generalizations.

  14. Singularities Inside Hairy Black Holes

    CERN Document Server

    Galtsov, D V; Zotov, M Yu

    1998-01-01

    We show that the Strong Cosmic Censorship is supported by the behavior of generic solutions on the class of static spherically symmetric black holes in gravitating gauge models and their stringy generalizations.

  15. Black hole accretion disc impacts

    CERN Document Server

    Pihajoki, Pauli

    2015-01-01

    We present an analytic model for computing the luminosity and spectral evolution of flares caused by a supermassive black hole impacting the accretion disc of another supermassive black hole. Our model includes photon diffusion, emission from optically thin regions and relativistic corrections to the observed spectrum and time-scales. We test the observability of the impact scenario with a simulated population of quasars hosting supermassive black hole binaries. The results indicate that for a moderate binary mass ratio of 0.3, and impact distances of 100 primary Schwarzschild radii, the accretion disc impacts can be expected to equal or exceed the host quasar in brightness at observed wavelength {\\lambda} = 510 nm up to z = 0.6. We conclude that accretion disc impacts may function as an independent probe for supermassive black hole binaries. We release the code used for computing the model light curves to the community.

  16. Space, time, and black holes

    Energy Technology Data Exchange (ETDEWEB)

    Darling, D.

    1980-10-01

    A discussion of Einstein's General Relativity and how it can explain black holes is included. The key idea of general relativity being that gravitational forces are a direct outcome of local curvature of space-time. The more mass something has the deeper the depression or well it causes in space-time. Black holes are supermassive objects, hence their gravity well is so steep even light can't escape. The three properties associated with a black hole are mass angular momentum, and electric charge. Non-rotating, Schwarzchild, and rotating, Kerr, black holes are studied. A Kruskal-Szekeres diagram for each type is given and explained. (SC)

  17. Surgical vs ultrasound-guided drainage of deep neck space abscesses: a randomized controlled trial: surgical vs ultrasound drainage

    OpenAIRE

    2013-01-01

    Introduction Deep neck space abscesses (DNAs) are relatively common otolaryngology-head and neck surgery emergencies and can result in significant morbidity with potential mortality. Traditionally, surgical incision and drainage (I&D) with antibiotics has been the mainstay of treatment. Some reports have suggested that ultrasound-guided drainage (USD) is a less invasive and effective alternative in select cases. Objectives To compare I&D vs USD of well-defined DNAs, using a randomized control...

  18. The Black Hole Universe Model

    Science.gov (United States)

    Zhang, Tianxi

    2014-06-01

    The black hole universe model is a multiverse model of cosmology recently developed by the speaker. According to this new model, our universe is a fully grown extremely supermassive black hole, which originated from a hot star-like black hole with several solar masses, and gradually grew up from a supermassive black hole with million to billion solar masses to the present state with trillion-trillion solar masses by accreting ambient matter or merging with other black holes. The entire space is structured with infinite layers or universes hierarchically. The innermost three layers include the universe that we live, the inside star-like and supermassive black holes called child universes, and the outside space called mother universe. The outermost layer is infinite in mass, radius, and entropy without an edge and limits to zero for both the matter density and absolute temperature. All layers are governed by the same physics and tend to expand physically in one direction (outward or the direction of increasing entropy). The expansion of a black hole universe decreases its density and temperature but does not alter the laws of physics. The black hole universe evolves iteratively and endlessly without a beginning. When one universe expands out, a new similar one is formed from inside star-like and supermassive black holes. In each of iterations, elements are resynthesized, matter is reconfigurated, and the universe is renewed rather than a simple repeat. The black hole universe is consistent with the Mach principle, observations, and Einsteinian general relativity. It has only one postulate but is able to explain all phenomena occurred in the universe with well-developed physics. The black hole universe does not need dark energy for acceleration and an inflation epoch for flatness, and thus has a devastating impact on the big bang model. In this talk, I will present how this new cosmological model explains the various aspects of the universe, including the origin

  19. Geometric inequalities for black holes

    CERN Document Server

    Dain, Sergio

    2014-01-01

    It is well known that the three parameters that characterize the Kerr black hole (mass, angular momentum and horizon area) satisfy several important inequalities. Remarkably, some of these inequalities remain valid also for dynamical black holes. This kind of inequalities play an important role in the characterization of the gravitational collapse. They are closed related with the cosmic censorship conjecture. In this article recent results in this subject are reviewed.

  20. Tensor Network and Black Hole

    CERN Document Server

    Matsueda, Hiroaki; Hashizume, Yoichiro

    2012-01-01

    A tensor network formalism of thermofield dynamics is introduced. The formalism relates the original Hilbert space with its tilde space by a product of two copies of a tensor network. Then, their interface becomes an event horizon, and the logarithm of the tensor rank corresponds to the black hole entropy. Eventually, multiscale entanglement renormalization anzats (MERA) reproduces an AdS black hole at finite temperature. Our finding shows rich functionalities of MERA as efficient graphical representation of AdS/CFT correspondence.

  1. Drainage pits in cohesionless materials: implications for surface of Phobos.

    Science.gov (United States)

    Horstman, K C; Melosh, H J

    1989-09-10

    Viking orbiter images show grooves and chains of pits crossing the surface of Phobos, many of which converge toward the large crater Stickney or its antipode. Although it has been proposed that the pits and grooves are chains of secondary craters, their morphology and geometric relations suggest that they are the surface traces of fractures in the underlying solid body of Phobos. Several models have been proposed to explain the pits, of which the most plausible are gas venting and drainage of regolith into open fractures. the latter mechanism is best supported by the image data and is the mechanism studied in this investigation. Drainage pits and fissures are modeled experimentally by using two rigid substrate plates placed edge to edge and covered by uniform thicknesses of dry fragmental debris (simulated regolith). Fracture extension is simulated by drawing the plates apart, allowing drainage of regolith into the newly created void. A typical drainage experiment begins with a shallow depression on the surface of the regolith, above the open fissure. Increased drainage causes local drainage pits to form; continued drainage causes the pits to coalesce, forming a cuspate groove. The resulting experimental patterns of pits and grooves have pronounced similarities to those observed on Phobos. Characteristics such as lack of raised rims, linearity of grooves and chains of pits, uniform spacing of pits, and progression from discrete pits to cuspate grooves are the same in the experiments and on Phobos. In contrast, gas-venting pits occur in irregular chains and have raised rims. These experiments thus indicate that the Phobos grooves and pits formed as drainage structures. The pit spacing in an experiment is measured at the time that the maximum number of pits forms, prior to groove development. The average pit spacing is compared to the regolith thickness for each material. Regression line fits indicate that the average spacing of drainage pits in unconsolidated

  2. Black holes as parts of entangled systems

    Science.gov (United States)

    Basini, G.; Capozziello, S.; Longo, G.

    A possible link between EPR-type quantum phenomena and astrophysical objects like black holes, under a new general definition of entanglement, is established. A new approach, involving backward time evolution and topology changes, is presented bringing to a definition of the system black hole-worm hole-white hole as an entangled system.

  3. Accretion, primordial black holes and standard cosmology

    Indian Academy of Sciences (India)

    B Nayak; P Singh

    2011-01-01

    Primordial black holes evaporate due to Hawking radiation. We find that the evaporation times of primordial black holes increase when accretion of radiation is included. Thus, depending on accretion efficiency, more primordial black holes are existing today, which strengthens the conjecture that the primordial black holes are the proper candidates for dark matter.

  4. The 2002 Antarctic Ozone Hole

    Science.gov (United States)

    Newman, P. A.; Nash, E. R.; Douglass, A. R.; Kawa, S. R.

    2003-01-01

    Since 1979, the ozone hole has grown from near zero size to over 24 Million km2. This area is most strongly controlled by levels of inorganic chlorine and bromine oncentrations. In addition, dynamical variations modulate the size of the ozone hole by either cooling or warming the polar vortex collar region. We will review the size observations, the size trends, and the interannual variability of the size. Using a simple trajectory model, we will demonstrate the sensitivity of the ozone hole to dynamical forcing, and we will use these observations to discuss the size of the ozone hole during the 2002 Austral spring. We will further show how the Cly decreases in the stratosphere will cause the ozone hole to decrease by 1-1.5% per year. We will also show results from a 3-D chemical transport model (CTM) that has been continuously run since 1999. These CTM results directly show how strong dynamics acts to reduce the size of the ozone hole.

  5. Evolution of supermassive black holes

    CERN Document Server

    Volonteri, M

    2006-01-01

    Supermassive black holes (SMBHs) are nowadays believed to reside in most local galaxies, and the available data show an empirical correlation between bulge luminosity - or stellar velocity dispersion - and black hole mass, suggesting a single mechanism for assembling black holes and forming spheroids in galaxy halos. The evidence is therefore in favour of a co-evolution between galaxies, black holes and quasars. In cold dark matter cosmogonies, small-mass subgalactic systems form first to merge later into larger and larger structures. In this paradigm galaxy halos experience multiple mergers during their lifetime. If every galaxy with a bulge hosts a SMBH in its center, and a local galaxy has been made up by multiple mergers, then a black hole binary is a natural evolutionary stage. The evolution of the supermassive black hole population clearly has to be investigated taking into account both the cosmological framework and the dynamical evolution of SMBHs and their hosts. The seeds of SMBHs have to be looked ...

  6. Intermediate-Mass Black Holes

    CERN Document Server

    Miller, M C

    2004-01-01

    The mathematical simplicity of black holes, combined with their links to some of the most energetic events in the universe, means that black holes are key objects for fundamental physics and astrophysics. Until recently, it was generally believed that black holes in nature appear in two broad mass ranges: stellar-mass (roughly 3-20 solar masses), which are produced by the core collapse of massive stars, and supermassive (millions to billions of solar masses), which are found in the centers of galaxies and are produced by a still uncertain combination of processes. In the last few years, however, evidence has accumulated for an intermediate-mass class of black holes, with hundreds to thousands of solar masses. If such objects exist they have important implications for the dynamics of stellar clusters, the formation of supermassive black holes, and the production and detection of gravitational waves. We review the evidence for intermediate-mass black holes and discuss future observational and theoretical work t...

  7. Bounds on Black Hole Spins

    CERN Document Server

    Daly, Ruth A

    2009-01-01

    Beam powers and black hole masses of 48 extended radio sources are combined to obtain lower bounds on the spins and magnetic field strengths of supermassive black holes. This is done in the context of the models of Blandford & Znajek (1977) (the 'BZ' model) and Meier (1999); a parameterization for bounds in the context of other models is suggested. The bounds obtained for very powerful classical double radio sources in the BZ model are consistent with black hole spins of order unity for sources at high redshift. The black hole spins are largest for the highest redshift sources and decrease for sources at lower redshift; the sources studied have redshifts between zero and two. Lower power radio sources associated with central dominant galaxies may have black hole spins that are significantly less than one. Combining this analysis with other results suggests that the maximum values of black hole spin associated with powerful radio galaxies decline from values of order unity at a redshift of 2 to values of o...

  8. Magnetic Black Holes Are Also Unstable

    CERN Document Server

    Kim, Sang Pyo

    2004-01-01

    Most black holes are known to be unstable to emitting Hawking radiation (in asymptotically flat spacetime). If the black holes are non-extreme, they have positive temperature and emit thermally. If they are extremal rotating black holes, they still spontaneously emit particles like gravitons and photons. If they are extremal electrically charged black holes, they are unstable to emitting electrons or positrons. The only exception would be extreme magnetically charged black holes if there do not exist any magnetic monopoles for them to emit. However, here we show that even in this case, vacuum polarization causes all magnetic black holes to be unstable to emitting smaller magnetic black holes.

  9. How objective is black hole entropy?

    CERN Document Server

    Lau, Y K

    1994-01-01

    The objectivity of black hole entropy is discussed in the particular case of a Schwarzchild black hole. Using Jaynes' maximum entropy formalism and Euclidean path integral evaluation of partition function, it is argued that in the semiclassical limit when the fluctutation of metric is neglected, the black hole entropy of a Schwarzchild black hole is equal to the maximal information entropy of an observer whose sole knowledge of the black hole is its mass. Black hole entropy becomes a measure of number of its internal mass eigenstates in accordance with the Boltzmann principle only in the limit of negligible relative mass fluctutation. {}From the information theoretic perspective, the example of a Schwarzchild black hole seems to suggest that black hole entropy is no different from ordinary thermodynamic entropy. It is a property of the experimental data of a black hole, rather than being an intrinsic physical property of a black hole itself independent of any observer. However, it is still weakly objective in...

  10. Erratic Black Hole Regulates Itself

    Science.gov (United States)

    2009-03-01

    New results from NASA's Chandra X-ray Observatory have made a major advance in explaining how a special class of black holes may shut off the high-speed jets they produce. These results suggest that these black holes have a mechanism for regulating the rate at which they grow. Black holes come in many sizes: the supermassive ones, including those in quasars, which weigh in at millions to billions of times the mass of the Sun, and the much smaller stellar-mass black holes which have measured masses in the range of about 7 to 25 times the Sun's mass. Some stellar-mass black holes launch powerful jets of particles and radiation, like seen in quasars, and are called "micro-quasars". The new study looks at a famous micro-quasar in our own Galaxy, and regions close to its event horizon, or point of no return. This system, GRS 1915+105 (GRS 1915 for short), contains a black hole about 14 times the mass of the Sun that is feeding off material from a nearby companion star. As the material swirls toward the black hole, an accretion disk forms. This system shows remarkably unpredictable and complicated variability ranging from timescales of seconds to months, including 14 different patterns of variation. These variations are caused by a poorly understood connection between the disk and the radio jet seen in GRS 1915. Chandra, with its spectrograph, has observed GRS 1915 eleven times since its launch in 1999. These studies reveal that the jet in GRS 1915 may be periodically choked off when a hot wind, seen in X-rays, is driven off the accretion disk around the black hole. The wind is believed to shut down the jet by depriving it of matter that would have otherwise fueled it. Conversely, once the wind dies down, the jet can re-emerge. "We think the jet and wind around this black hole are in a sort of tug of war," said Joseph Neilsen, Harvard graduate student and lead author of the paper appearing in the journal Nature. "Sometimes one is winning and then, for reasons we don

  11. Nitrogen budget in the Changjiang River drainage area

    Institute of Scientific and Technical Information of China (English)

    JIANG Tao; YU Zhiming; SONG Xiuxian; CAO Xihua

    2012-01-01

    We established a budget model of nitrogen (N) inputs and outputs between watersheds and waterbodies to determine the sources of riverine N in the Changjiang (Yangtze) River drainage area.Nitrogen inputs in the budget included N from synthetic fertilizer,biological fixation by leguminous and other crops,wet/dry atmospheric deposition,excreta from humans and animals,and crop residues.The total N input was estimated to be 17.6 Tg,of which 20% or 3.5 Tg N was transported into waterbodies.Of the total N transported into waterbodies,the largest proportion was N from animal waste (26%),followed by N from atmospheric wet/dry deposition (25%),synthetic fertilizer N (17%),N in sewage wastes (17%),N in human waste from rural areas (6%) and industrial wastewater N (9%).We studied the spatial patterns of N inputs and outputs by dividing the Changjiang River drainage area into four sub-basins,from upstream to downstream:the Tongtian River drainage area (TTD,the headwater drainage area,138 000 km2,less disturbed by human activities); the Jinsha River drainage area (JSD,347 000 km2,less disturbed by human activities,approx.3 500 km upstream of the Changjiang estuary); the Pingshan-Yichang drainage area (PYD,520 500 km2,large-scale human disturbance,about 2 000 km upstream of the Changjiang estuary);and the Yichang-Datong drainage area (YDD,699 900 km2,large-scale human disturbance,approx.620 km upstream of the Changjiang estuary).The average N input into waterbodies was 2.3,7.3,24.1,and 28.2 kg N/ha in the TTD,JSD,PYD,and YDD sub-basins,respectively,suggesting an increase of N-components of more than 10 times from upstream to downstream areas.

  12. Geochemical characterisation of seepage and drainage water quality from two sulphide mine tailings impoundments: Acid mine drainage versus neutral mine drainage

    Science.gov (United States)

    Heikkinen, P.M.; Raisanen, M.L.; Johnson, R.H.

    2009-01-01

    Seepage water and drainage water geochemistry (pH, EC, O2, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.

  13. 厚煤层瓦斯抽放钻车研制%Development of Drilling Car for Thick Coal Seam Gas Drainage

    Institute of Scientific and Technical Information of China (English)

    李旭珍; 李强

    2016-01-01

    Based on the requirements of coal mine tunnel gas drainage drilling ,the tunnel gas drainage drilling cars were studied ,and a deep‐hole drilling car for thick coal seam was developed ,which could effectively reduce the auxiliary work time and improve the working efficiency .%根据厚煤层矿井坑道瓦斯抽放钻孔的要求,对坑道瓦斯抽放钻机进行了研究,研制了适合厚煤层钻孔施工的煤矿用深孔钻车,有效地减少了辅助工作时间,提高了工作效率。

  14. Regular black hole in three dimensions

    OpenAIRE

    Myung, Yun Soo; Yoon, Myungseok

    2008-01-01

    We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

  15. Efficiency of lachrymal sac drainage in newborns with dacryocystocele

    Directory of Open Access Journals (Sweden)

    Sakovich V.N.

    2016-12-01

    Full Text Available The article represents results of treatment of 14 newborns with unilateral dacryocystocele. Patients age was 7.2±0.5 days. In 9 newborns (64.3% dacryocystocele was complicated with lachrymal sac phlegmon; in 5 children (35.7% any complications were absent. Drainage of lachrymal sac through the lower lachrymal canaliculus, instillation of antibiotics, systemic antibiotic therapy in case of phlegmon were performed in all the children. Lachrymal sac washing was performed with a solution of the antibiotic ofloxacin till clear fluid evacuation. If necessary the drainage was repeated in 10 days. The drainage of lachrymal sac was successful in all the patients. 2-3 weeks after the drainage probing of nasolachrymal duct was perfomed in 4 children (28.6% including those 3 with lacrymal sac phlegmon. In 71.4% regression of dacryocystocele occurred itself. Any complications and side effects were not observed. Positive effect of the drainage, according to the authors, can be explained so that dilatation of lachrymal canaliculus before the procedure allows to eliminate Rosenmьller valve stenosis and evacuation of fluid, mucus and pus, being breeding ground for microorganisms from lachrymal sac, promotes inflammation subsiding. Authors also recommend to pay attention on prenatal diagnosis of dacryocystocele, using ultrasound investigation in the 3rd trimester of pregnancy.

  16. Current status of preoperative drainage for distal biliary obstruction

    Institute of Scientific and Technical Information of China (English)

    Harutoshi; Sugiyama; Toshio; Tsuyuguchi; Yuji; Sakai; Rintaro; Mikata; Shin; Yasui; Yuto; Watanabe; Dai; Sakamoto; Masato; Nakamura; Reina; Sasaki; Jun-ichi; Senoo; Yuko; Kusakabe; Masahiro; Hayashi; Osamu; Yokosuka

    2015-01-01

    Preoperative biliary drainage(PBD) was developed to improve obstructive jaundice, which affects a number of organs and physiological mechanisms in patients waiting for surgery. However, its role in patients who will undergo pancreaticoduodenectomy for biliary obstruction remains controversial. This article aims to review the current status of the use of preoperative drainage for distal biliary obstruction. Relevant articles published from 1980 to 2015 were identified by searching MEDLINE and Pub Med using the keywords "PBD", "pancreaticoduodenectomy", and "obstructive jaundice". Additional papers were identified by a manual search of the references from key articles. Current studies have demonstrated that PBD should not be routinely performed because of the postoperative complications. PBD should only be considered in carefully selected patients, particularly in cases where surgery had to be delayed. PBD may be needed in patients with severe jaundice, concomitant cholangitis, or severe malnutrition. The optimal method of biliary drainage has yet to be confirmed. PBD should be performed by endoscopic routes rather than by percutaneous routes to avoid metastatic tumor seeding. Endoscopic stenting or nasobiliary drainage can be selected. Although more expensive, the use of metallic stents remains a viable option to achieve effective drainage without cholangitis and reintervention.

  17. Basinsoft, a computer program to quantify drainage basin characteristics

    Science.gov (United States)

    Harvey, Craig A.; Eash, David A.

    2001-01-01

    Surface water runoff is a function of many interrelated factors including climate, soils, landuse, and the physiography of the drainage basin. A practical and effective method to quantify drainage basin characteristics would allow analysis of the interrelations of these factors, leading to an improved understanding of the effects of drainage basin characteristics on surface-water runoff. Historically, the quantification of drainage basin characteristics has been a tedious and time-consuming process. Recent improvements in computer hardware and software technology have enabled the developers of a program called Basinsoft to automate this process. Basinsoft requires minimal preprocessing of data and provides an efficient, automated procedure for quantifying selected morphometric characteristics and the option to area-weight characteristics for a drainage basin. The user of Basinsoft is assumed to have a limited amount of experience in the use of ARC/INFO, a proprietary geographic information system (GIS). (The use of brand names in this chapter is for identification purposes only and does not constitute endorsement by the U.S. Geological Survey [USGS].)

  18. Connected subglacial lake drainage beneath Thwaites Glacier, West Antarctica

    Science.gov (United States)

    Smith, Benjamin E.; Gourmelen, Noel; Huth, Alexander; Joughin, Ian

    2017-02-01

    We present conventional and swath altimetry data from CryoSat-2, revealing a system of subglacial lakes that drained between June 2013 and January 2014 under the central part of Thwaites Glacier, West Antarctica (TWG). Much of the drainage happened in less than 6 months, with an apparent connection between three lakes spanning more than 130 km. Hydro-potential analysis of the glacier bed shows a large number of small closed basins that should trap water produced by subglacial melt, although the observed large-scale motion of water suggests that water can sometimes locally move against the apparent potential gradient, at least during lake-drainage events. This shows that there are important limitations in the ability of hydro-potential maps to predict subglacial water flow. An interpretation based on a map of the melt rate suggests that lake drainages of this type should take place every 20-80 years, depending on the connectivity of the water flow at the bed. Although we observed an acceleration in the downstream part of TWG immediately before the start of the lake drainage, there is no clear connection between the drainage and any speed change of the glacier.

  19. Management of chest drainage tubes after lung surgery.

    Science.gov (United States)

    Satoh, Yukitoshi

    2016-06-01

    Since chest tubes have been routinely used to drain the pleural space, particularly after lung surgery, the management of chest tubes is considered to be essential for the thoracic surgeon. The pleural drainage system requires effective drainage, suction, and water-sealing. Another key point of chest tube management is that a water seal is considered to be superior to suction for most air leaks. Nowadays, the most common pleural drainage device attached to the chest tube is the three-bottle system. An electronic chest drainage system has been developed that is effective in standardizing the postoperative management of chest tubes. More liberal use of digital drainage devices in the postoperative management of the pleural space is warranted. The removal of chest tubes is a common procedure occurring almost daily in hospitals throughout the world. Extraction of the tube is usually done at the end of full inspiration or at the end of full expiration. The tube removal technique is not as important as how it is done and the preparation for the procedure. The management of chest tubes must be based on careful observation, the patient's characteristics, and the operative procedures that had been performed.

  20. Bubble motion measurements during foam drainage and coarsening.

    Science.gov (United States)

    Maurdev, G; Saint-Jalmes, A; Langevin, D

    2006-08-15

    We have studied bubble motion within a column of foam allowed to undergo free drainage. We have measured bubble motion upward with time and as a function of their initial positions. Depending on the gas used, which sets the coarsening and drainage rates, different bubble upward motion types have been identified (constant speed, acceleration or deceleration) and explained in relation with liquid downward flows. The proofs of the consistency between bubble upward motion and liquid downward flow are obtained both by comparing the bubble motion curves to the liquid drainage ones, and by comparing the time variations of the liquid fraction extracted from bubble motion to direct liquid fraction measurements by electrical conductimetry. The agreement between bubble position tracking and electrical conductivity shows in particular that it is possible to determine the drainage regime from such simple bubble motion measurements. This work also allowed us to demonstrate a special case of foam coarsening and expansion, occurring when the foam gas is less soluble than the outside one, caused by diffusion of this external gas into the foam. All these results allow us to build a picture of drainage and coarsening seen from the bubble point of view.

  1. Could supermassive black holes be quintessential primordial black holes?

    CERN Document Server

    Bean, R; Bean, Rachel; Magueijo, Joao

    2002-01-01

    There is growing observational evidence for a population of supermassive black holes (SMBHs) in galactic bulges. We examine in detail the conditions under which these black holes must have originated from primordial black holes (PBHs). We consider the merging and accretion history experienced by SMBHs to find that, whereas it is possible that they were formed by purely astrophysical processes, this is unlikely and most probably a populations of primordial progenitors is necessary. We identify the mass distribution and comoving density of this population and then propose a cosmological scenario producing PBHs with the right properties. Although this is not essential we consider PBHs produced at the end of a period of inflation with a blue spectrum of fluctuations. We constrain the value of the spectral tilt in order to obtain the required PBH comoving density. We then assume that PBHs grow by accreting quintessence showing that their mass scales like the horizon mass while the quintessence field itself is scal...

  2. Time-course of perceptual processing of "hole" and "no-hole"figures: An ERP study

    Institute of Scientific and Technical Information of China (English)

    Weina Zhu; Junjun Zhang; Changle Zhou

    2013-01-01

    Closure or the presence of a "hole" is an emergent perceptual feature that can be extracted by the visual system early on.This feature has been shown to have perceptual advantages over openness or "no-hole".In this study,we investigated when and how the human brain differentiates between "hole" and "no-hole" figures.Event-related potentials (ERPs) were recorded during a passive observation paradigm.Two pairs of simple figures (Experiment 1) and two sets of Greek letters (Experiment 2) were used as stimuli.The ERPs of "hole" and "no-hole"figures differed ~90 ms after stimulus onset:"hole"figures elicited smaller P1 and N1 amplitudes than "no-hole" figures.These suggest that both P1 and N1 components are sensitive to the difference between "hole" and "no-hole" figures; perception of "hole" and "no-hole" figures might be differentiated early during visual processing.

  3. Information locking in black holes

    CERN Document Server

    Smolin, J; Smolin, John; Oppenheim, Jonathan

    2005-01-01

    The black hole information loss paradox has plagued physicists since Hawking's discovery that black holes evaporate. The calculation suggests that information thrown into a black hole is evaporated away as thermal radiation, and is destroyed: either the unitary laws of quantum theory break down, or we must modify the laws of general relativity. Here we show that one of the central presumptions of the debate is incorrect. Ensuring that information not escape during the semi-classical evaporation process does not require that all the information remain in the black hole until the final stages of evaporation. By taking into account recent results in quantum information theory, we find that the amount of information that must remain in the black hole until the final stages of evaporation can be very small, even though the amount of information which has already radiated away is negligible. Quantum effects mean that information need not be additive: a small number of quanta can lock a large amount of information, ...

  4. Force-feeding Black Holes

    CERN Document Server

    Begelman, Mitchell C

    2012-01-01

    We propose that the growth of supermassive black holes is associated mainly with brief episodes of highly super-Eddington infall of gas ("hyperaccretion"). This gas is not swallowed in real time, but forms an envelope of matter around the black hole that can be swallowed gradually, over a much longer timescale. However, only a small fraction of the black hole mass can be stored in the envelope at any one time. We argue that any infalling matter above a few per cent of the hole's mass is ejected as a result of the plunge in opacity at temperatures below a few thousand degrees K, corresponding to the Hayashi track. The speed of ejection of this matter, compared to the velocity dispersion (sigma) of the host galaxy's core, determines whether the ejected matter is lost forever or returns eventually to rejoin the envelope, from which it can be ultimately accreted. The threshold between matter recycling and permanent loss defines a relationship between the maximum black hole mass and sigma that resembles the empiri...

  5. Resource Letter BH-2: Black Holes

    CERN Document Server

    Gallo, Elena

    2008-01-01

    This resource letter is designed to guide students, educators, and researchers through (some of) the literature on black holes. Both the physics and astrophysics of black holes are discussed. Breadth has been emphasized over depth, and review articles over primary sources. We include resources ranging from non-technical discussions appropriate for broad audiences to technical reviews of current research. Topics addressed include classification of stationary solutions, perturbations and stability of black holes, numerical simulations, collisions, the production of gravity waves, black hole thermodynamics and Hawking radiation, quantum treatments of black holes, black holes in both higher and lower dimensions, and connections to nuclear and condensed matter physics. On the astronomical end, we also cover the physics of gas accretion onto black holes, relativistic jets, gravitationally red-shifted emission lines, evidence for stellar-mass black holes in binary systems and super-massive black holes at the centers...

  6. Drainage filter technologies to mitigate site-specific phosphorus losses

    DEFF Research Database (Denmark)

    Kjærgaard, Charlotte; Heckrath, Goswin Johann; Iversen, Bo Vangsø;

    2014-01-01

    high risks areas of P loss and applying site-specific measures therefore seems a more cost-efficient approach. The Danish Commission for Nature and Agriculture has now called for a shift of paradigm towards targeted mitigation and development of new, cost-efficient technologies to mitigate site......-specific nutrient losses in drainage. The “SUPREME-TECH” project (2010-2015), funded by the Danish Strategic Research Council, aims at providing the scientific basis for developing cost-effective drainage filter technologies to retain P in agricultural drainage waters. The project studies different approaches......-scale surface-flow constructed wetland. In the former, various natural and industrial P filter substrates have been tested for their ability to reduce inlet P concentrations to below environmental threshold values (

  7. Electronic versus traditional chest tube drainage following lobectomy

    DEFF Research Database (Denmark)

    Lijkendijk, Marike; Licht, Peter B; Neckelmann, Kirsten

    2015-01-01

    OBJECTIVES: Electronic drainage systems have shown superiority compared with traditional (water seal) drainage systems following lung resections, but the number of studies is limited. As part of a medico-technical evaluation, before change of practice to electronic drainage systems for routine...... thoracic surgery, we conducted a randomized controlled trial (RCT) investigating chest tube duration and length of hospitalization. METHODS: Patients undergoing lobectomy were included in a prospective open label RCT. A strict algorithm was designed for early chest tube removal, and this decision...... time for chest tube removal, as well as length of hospitalization. RESULTS: A total of 105 patients were randomized. We found no significant difference between the electronic group and traditional group in optimal chest tube duration (HR = 0.83; 95% CI: 0.55-1.25; P = 0.367), actual chest tube duration...

  8. Urban Drainage System Improvement for Climate Change Adaptation

    Directory of Open Access Journals (Sweden)

    Narae Kang

    2016-06-01

    Full Text Available Recently, urban areas have experienced frequent, large-scale flooding, a situation that has been aggravated by climate change. This study aims to improve the urban drainage system to facilitate climate change adaptation. A methodology and a series of mitigation strategies are presented to efficiently improve the urban drainage system in light of climate change. In addition, we assess the impact of climate change and predict the scale of potential future flood damage by applying the methodology and mitigation strategies to urban areas. Based on the methodology presented, urban flood prevention measures for Gyeyang-gu (Province, Incheon, Korea, was established. The validity of the proposed alternatives is verified by assessing the economic feasibility of the projects to reduce flood damage. We expect that the methodology presented will aid the decision-making process and assist in the development of reasonable strategies to improve the urban drainage system for adaptation to climate change.

  9. Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

    Energy Technology Data Exchange (ETDEWEB)

    Grin, A. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2014-09-01

    The goal of this research is to provide durable and long-term water management solutions using exterior insulating sheathing as part of the water management system. It is possible to tape or seal the joints in insulating sheathing to create a drainage plane and even an air control layer. There exists the material durability component of the tape as well as the system durability component being the taped insulating sheathing as the drainage plane. This measure guideline provides best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant issues were discussed with the group, which are required to make taped insulating sheathing a simple, long-term, and durable drainage plane: horizontal joints should be limited or eliminated wherever possible; where a horizontal joint exists use superior materials; and frequent installation inspection and regular trade training are required to maintain proper installation.

  10. A new thermogeomechanical theory for gravity drainage in SAGD

    Energy Technology Data Exchange (ETDEWEB)

    Cokar, M.; Kallos, M.S.; Gates, I.D. [Dept. of Chemical and Petroleum Engineering, University of Calgary (Canada)

    2011-07-01

    In the heavy oil and bitumen industry, the steam assisted gravity drainage (SAGD) process is often used to enhance oil recovery. In such deposits, oil usually has no mobility due to its high viscosity and the injection of steam leads to an increase in the mobility of bitumen. Since the thermogeomechanical evolution of the oil sand at the chamber edge is important to the SAGD's performance, this paper aimed at taking these effects into account in a new SAGD drainage formula. The SAGD theory was modified to incorporate the effects of geomechanics and the results were then compared with Butler's model and the Sharma and Gates model. Results showed that thermal expansion has an important impact on oil rates and that geomechanical effects need to be considered when analysing the flow at the edge of steam chambers. This study developed a SAGD drainage formula and demonstrated the importance of geomechanics in the SAGD's performance.

  11. Gas drainage management systems for modern coal mines

    Energy Technology Data Exchange (ETDEWEB)

    Creedy, D.; Lunarzewski, L. [Wardell Armstrong, Newcastle-under-Lyme (United Kingdom)

    2001-07-01

    Gas emission and outburst problems remain one of the major difficulties facing the world coal mining industry. Methane emission in coal mines adversely affects the efficiency of coal production and mine safety conditions. Risk can be reduced by gas drainage. The methane thus recovered is a potentially valuable energy source which if used can produce both financial and environmental benefits. The generic gas control methods of gas drainage and ventilation are common to most coal mining countries but the detailed technologies applied differ according to the geological, mining and economic conditions, and also with the magnitudes of coal production. However, the critical element of all gas drainage management systems is the management organisation which ensures allocation of responsibility and provides a systematic framework for effective application of the most appropriate technology. 8 refs., 6 figs., 1 tab.

  12. [Endosonography control of percutaneous paracoccygeal drainage of deep pelvic abscesses after rectum resection].

    Science.gov (United States)

    Truong, S; Willis, S; Jansen, M; Neuerburg, J; Schumpelick, V

    1997-06-01

    Pelvic abscesses are severe complications after rectal surgery. In recent years, surgical drainage has been edged out by percutaneous drainage techniques. We report our experience with the drainage of postoperative pelvic abscesses via the paracoccygeal route controlled by endosonography. In eight patients the diagnosis of a retrorectal pelvic abscess was established by endosonography and confirmed by endosonographically controlled exploratory puncture. Drainage of the abscesses was performed via the paracoccygeal access route by trocar or Seldinger technique under permanent visual control by endoluminal sonography. Irrigation of the abscess cavity was than performed daily. In all cases drainage was successful without complications. Duration of drainage was 9-14 days with a mean of 10.8 days. In one patient there was a recurrence of the abscess because of early removal of the drainage catheter. Because of its overall availability and its good results, paracoccygeal percutaneous endosonographically controlled drainage seems to be a suitable uncomplicated method for drainage of postoperative pelvic abscesses.

  13. Black Hole Blows Big Bubble

    Science.gov (United States)

    2010-07-01

    Combining observations made with ESO's Very Large Telescope and NASA's Chandra X-ray telescope, astronomers have uncovered the most powerful pair of jets ever seen from a stellar black hole. This object, also known as a microquasar, blows a huge bubble of hot gas, 1000 light-years across, twice as large and tens of times more powerful than other known microquasars. The discovery is reported this week in the journal Nature. "We have been astonished by how much energy is injected into the gas by the black hole," says lead author Manfred Pakull. "This black hole is just a few solar masses, but is a real miniature version of the most powerful quasars and radio galaxies, which contain black holes with masses of a few million times that of the Sun." Black holes are known to release a prodigious amount of energy when they swallow matter. It was thought that most of the energy came out in the form of radiation, predominantly X-rays. However, the new findings show that some black holes can release at least as much energy, and perhaps much more, in the form of collimated jets of fast moving particles. The fast jets slam into the surrounding interstellar gas, heating it and triggering an expansion. The inflating bubble contains a mixture of hot gas and ultra-fast particles at different temperatures. Observations in several energy bands (optical, radio, X-rays) help astronomers calculate the total rate at which the black hole is heating its surroundings. The astronomers could observe the spots where the jets smash into the interstellar gas located around the black hole, and reveal that the bubble of hot gas is inflating at a speed of almost one million kilometres per hour. "The length of the jets in NGC 7793 is amazing, compared to the size of the black hole from which they are launched," says co-author Robert Soria [1]. "If the black hole were shrunk to the size of a soccer ball, each jet would extend from the Earth to beyond the orbit of Pluto." This research will help

  14. Nocturnal drainage wind characteristics in two converging air sheds

    Energy Technology Data Exchange (ETDEWEB)

    Gedayloo, T.; Clements, W.E.; Barr, S.; Archuleta, J.A.

    1980-01-01

    During the short experimental period in the Grants Basin of Northeastern New Mexico a survey was conducted on the complex meteorology of this area. Emphasis was placed on the nocturnal drainage flow because of the potential hazards to the populated areas of Milan and Grants from the effluents of the uranium mining and milling operation in this area. This investigation has shown that the nocturnal drainage flow patterns agree with the winds predicted on the basis of the complex terrain of the area. Because of the surface cooling at night (over 25/sup 0/C during summer and about 20/sup 0/C during winter), air from elevated surrounding areas flows to the low lying regions consequently setting up a nocturnal drainage flow. This regime exists over 60% of the time during summer months and over 65% of the time during winter months with a depth generally less than 200 m. In the San Mateo air shed the drainage flow is east northeast, and in the Ambrosia Lake air shed it is from northwest. The confluence of these two air flows contributes mainly to the drainage flow through the channel formed by La Ja Mesa and Mesa Montanosa. The analysis of data collected by the recording Flats Station confirms the prediction that although the area south of the channel region broadens considerably causing a reduction in flow speed, contributions from the southside of La Jara Mesa and Mesa Montanosa partly compensate for this reduction. The position of this recording station is 15 to 20 km from the populated towns of Milan and Grants. A drainage flow speed of approximately 2.2 m s/sup -1/ and the duration of over 11 hours as recorded by this station indicates that air from the San Mateo and Ambrosia Lake regions may be transported southwards to these population centers during a nocturnal period. In order to test this prediction, a series of multi-atmospheric tracer experiments were conducted in the Grants Basin.

  15. Lee-Wick Black Holes

    CERN Document Server

    Bambi, Cosimo; Wang, Yixu

    2016-01-01

    We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source $M$ exceeds a critical value $M_{\\rm crit}$. For $M > M_{\\rm crit}$ the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for $M = M_{\\rm crit}$ we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

  16. Volume inside old black holes

    Science.gov (United States)

    Christodoulou, Marios; De Lorenzo, Tommaso

    2016-11-01

    Black holes that have nearly evaporated are often thought of as small objects, due to their tiny exterior area. However, the horizon bounds large spacelike hypersurfaces. A compelling geometric perspective on the evolution of the interior geometry was recently shown to be provided by a generally covariant definition of the volume inside a black hole using maximal surfaces. In this article, we expand on previous results and show that finding the maximal surfaces in an arbitrary spherically symmetric spacetime is equivalent to a 1 +1 geodesic problem. We then study the effect of Hawking radiation on the volume by computing the volume of maximal surfaces inside the apparent horizon of an evaporating black hole as a function of time at infinity: while the area is shrinking, the volume of these surfaces grows monotonically with advanced time, up to when the horizon has reached Planckian dimensions. The physical relevance of these results for the information paradox and the remnant scenarios are discussed.

  17. Black holes and galaxy formation

    CERN Document Server

    Propst, Raphael J

    2010-01-01

    Galaxies are the basic unit of cosmology. The study of galaxy formation is concerned with the processes that formed a heterogeneous universe from a homogeneous beginning. The physics of galaxy formation is complicated because it deals with the dynamics of stars, thermodynamics of gas and energy production of stars. A black hole is a massive object whose gravitational field is so intense that it prevents any form of matter or radiation to escape. It is hypothesized that the most massive galaxies in the universe- "elliptical galaxies"- grow simultaneously with the supermassive black holes at their centers, giving us much stronger evidence that black holes control galaxy formation. This book reviews new evidence in the field.

  18. Disrupting Entanglement of Black Holes

    CERN Document Server

    Leichenauer, Stefan

    2014-01-01

    We study entanglement in thermofield double states of strongly coupled CFTs by analyzing two-sided Reissner-Nordstrom solutions in AdS. The central object of study is the mutual information between a pair of regions, one on each asymptotic boundary of the black hole. For large regions the mutual information is positive and for small ones it vanishes; we compute the critical length scale, which goes to infinity for extremal black holes, of the transition. We also generalize the butterfly effect of Shenker and Stanford to a wide class of charged black holes, showing that mutual information is disrupted upon perturbing the system and waiting for a time of order $\\log E/\\delta E$ in units of the temperature. We conjecture that the parametric form of this timescale is universal.

  19. Lee-Wick black holes

    Science.gov (United States)

    Bambi, Cosimo; Modesto, Leonardo; Wang, Yixu

    2017-01-01

    We derive and study an approximate static vacuum solution generated by a point-like source in a higher derivative gravitational theory with a pair of complex conjugate ghosts. The gravitational theory is local and characterized by a high derivative operator compatible with Lee-Wick unitarity. In particular, the tree-level two-point function only shows a pair of complex conjugate poles besides the massless spin two graviton. We show that singularity-free black holes exist when the mass of the source M exceeds a critical value Mcrit. For M >Mcrit the spacetime structure is characterized by an outer event horizon and an inner Cauchy horizon, while for M =Mcrit we have an extremal black hole with vanishing Hawking temperature. The evaporation process leads to a remnant that approaches the zero-temperature extremal black hole state in an infinite amount of time.

  20. Scrambling with matrix black holes

    Science.gov (United States)

    Brady, Lucas; Sahakian, Vatche

    2013-08-01

    If black holes are not to be dreaded sinks of information but rather fully described by unitary evolution, they must scramble in-falling data and eventually leak it through Hawking radiation. Sekino and Susskind have conjectured that black holes are fast scramblers; they generate entanglement at a remarkably efficient rate, with the characteristic time scaling logarithmically with the entropy. In this work, we focus on Matrix theory—M-theory in the light-cone frame—and directly probe the conjecture. We develop a concrete test bed for quantum gravity using the fermionic variables of Matrix theory and show that the problem becomes that of chains of qubits with an intricate network of interactions. We demonstrate that the black hole system evolves much like a Brownian quantum circuit, with strong indications that it is indeed a fast scrambler. We also analyze the Berenstein-Maldacena-Nastase model and reach the same tentative conclusion.

  1. Calabi-Yau black holes

    Science.gov (United States)

    Shmakova, Marina

    1997-07-01

    We find the entropy of N=2 extreme black holes associated with general Calabi-Yau moduli space and the prepotential F=dABC(XAXBXC/X0). We show that for arbitrary dABC and black hole charges p and q the entropy-area formula depends on combinations of these charges and parameters dABC. These combinations are the solutions of a simple system of algebraic equations. We give a few examples of particular Calabi-Yau moduli spaces for which this system has an explicit solution. For the special case when one of the black hole charges is equal to zero (p0=0) the solution always exists.

  2. Holes at High Blowing Ratios

    Directory of Open Access Journals (Sweden)

    Phillip M. Ligrani

    1996-01-01

    Full Text Available Experimental results are presented which describe the development and structure of flow downstream of a single row of holes with compound angle orientations producing film cooling at high blowing ratios. This film cooling configuration is important because similar arrangements are frequently employed on the first stage of rotating blades of operating gas turbine engines. With this configuration, holes are spaced 6d apart in the spanwise direction, with inclination angles of 24 degrees, and angles of orientation of 50.5 degrees. Blowing ratios range from 1.5 to 4.0 and the ratio of injectant to freestream density is near 1.0. Results show that spanwise averaged adiabatic effectiveness, spanwise-averaged iso-energetic Stanton number ratios, surveys of streamwise mean velocity, and surveys of injectant distributions change by important amounts as the blowing ratio increases. This is due to injectant lift-off from the test surface just downstream of the holes.

  3. Black holes with vector hair

    Science.gov (United States)

    Fan, Zhong-Ying

    2016-09-01

    In this paper, we consider Einstein gravity coupled to a vector field, either minimally or non-minimally, together with a vector potential of the type V = 2{Λ}_0+1/2{m}^2{A}^2 + {γ}_4{A}^4 . For a simpler non-minimally coupled theory with Λ0 = m = γ4 = 0, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first law of the extremal black holes is modified by a one form associated with the vector field. In particular, due to the existence of the non-minimal coupling, the vector forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first law. For a minimally coupled theory with Λ0 ≠ 0, we also obtain one class of asymptotically flat extremal black hole solutions in general dimensions. This is possible because the parameters ( m 2 , γ4) take certain values such that V = 0. In particular, we find that the vector also forms thermodynamic conjugates with the graviton mode and contributes to the corresponding first law, although the non-minimal coupling has been turned off. Thus all the extremal black hole solutions that we obtain provide highly non-trivial examples how the first law of thermodynamics can be modified by a either minimally or non-minimally coupled vector field. We also study Gauss-Bonnet gravity non-minimally coupled to a vector and obtain asymptotically flat black holes and Lifshitz black holes.

  4. Spontaneous drainage in syringomyelia: magnetic resonance imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Bogdanov, E.I.; Mendelevich, E.G. [Kazan State Medical Univ. (Russian Federation). Dept. of Neurology and Rehabilitation; Ibatullin, M.M. [Republic Medical Diagnostic Centre of Tatarstan, Kazan (Russian Federation). Department of Radiology

    2000-09-01

    We present five cases of syringomyelia associated with Chiari I or other causes of partial obstructions at the cervicomedullary junction, with spontaneous disruption of the wall of a cervical syrinx and formation of a communication between the cavity and the subarachnoid space, shown on axial MRI. MRI can be used to investigate the hydrodynamics, showing the liquid inside the disrupted syrinx wall and the pathway of drainage. The finding of spontaneous drainage may be important for understanding the pathogenesis of syringomyelia and may be helpful for choosing a surgical approach. (orig.)

  5. THE APPLICATION OF CATIONIC POLYACRYLAMIDE AS DRAINAGE AND RETENTION AIDS

    Institute of Scientific and Technical Information of China (English)

    JinWang; KefuChen; FushanChent; ChuanshanZhao; RendangYang

    2004-01-01

    Cationic polyacrylamide (CPAM) which was prepared through complex initiation system in laboratory and cationic polyacrylamide (Ciba) were used asretention and drainage aids for bleached wheat strawpulp. The influences of (polydiallyldimethlammonium chloride) PDADMAC and PDADMAC/CPAMon Zeta potential and drainability of pulp was investigated. The dual drainage and retention systems suchas CPAM/modified bentonite, CPAM/colloidal SiO2,as well as their comparison between the two systemswere discussed, and the optimal dosages of additiveswere determined. The results showed that: the complex systems can further enhance filler retention,drainability of pulp and strength properties of paper.

  6. Astrophysical Black Holes: Evidence of a Horizon?

    Science.gov (United States)

    Colpi, Monica

    In this Lecture Note we first follow a short account of the history of the black hole hypothesis. We then review on the current status of the search for astrophysical black holes with particular attention to the black holes of stellar origin. Later, we highlight a series of observations that reveal the albeit indirect presence of supermassive black holes in galactic nuclei, with mention to forthcoming experiments aimed at testing directly the black hole hypothesis. We further focus on evidences of a black hole event horizon in cosmic sources.

  7. Supersymmetric black holes in string theory

    Energy Technology Data Exchange (ETDEWEB)

    Mohaupt, T. [Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, Peach Street, Liverpool L69 7ZL (United Kingdom)

    2007-05-15

    We review recent developments concerning supersymmetric black holes in string theory. After a general introduction to the laws of black hole mechanics and to black hole entropy in string theory, we discuss black hole solutions in N=2 supergravity, special geometry, the black hole attractor equations and the underlying variational principle. Special attention is payed to the crucial role of higher derivative corrections. Finally we discuss black hole partition functions and their relation with the topological string, mainly from the supergravity perspective. We summarize the state of art and discuss various open questions and problems. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

  8. Geometric inequalities for black holes

    Energy Technology Data Exchange (ETDEWEB)

    Dain, Sergio [Universidad Nacional de Cordoba (Argentina)

    2013-07-01

    Full text: A geometric inequality in General Relativity relates quantities that have both a physical interpretation and a geometrical definition. It is well known that the parameters that characterize the Kerr-Newman black hole satisfy several important geometric inequalities. Remarkably enough, some of these inequalities also hold for dynamical black holes. This kind of inequalities, which are valid in the dynamical and strong field regime, play an important role in the characterization of the gravitational collapse. They are closed related with the cosmic censorship conjecture. In this talk I will review recent results in this subject. (author)

  9. Terahertz superconducting plasmonic hole array

    CERN Document Server

    Tian, Zhen; Han, Jiaguang; Gu, Jianqiang; Xing, Qirong; Zhang, Weili

    2010-01-01

    We demonstrate thermally tunable superconductor hole array with active control over their resonant transmission induced by surface plasmon polaritons . The array was lithographically fabricated on high temperature YBCO superconductor and characterized by terahertz-time domain spectroscopy. We observe a clear transition from the virtual excitation of the surface plasmon mode to the real surface plasmon mode. The highly tunable superconducting plasmonic hole arrays may have promising applications in the design of low-loss, large dynamic range amplitude modulation, and surface plasmon based terahertz devices.

  10. Black holes and warped spacetime

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, W.J. III

    1979-01-01

    Black holes (BHs) and their warping effect on spacetime are described, beginning with a discussion on stellar evolution that includes white dwarfs, supernovas and neutron stars. The structure of static, rotating, and electrically charged BHs are considered, as well as the general theory of relativity, quantum mechanics, the Einstein-Rosen bridge, and wormholes in spacetime. Attention is also given to gravitational lenses, various space geometries, quasars, Seyfert galaxies, supermassive black holes, the evaporation and particle emission of BHs, and primordial BHs, including their temperature and lifetime.

  11. Black Holes with Zero Mass

    CERN Document Server

    Nucamendi, U; Nucamendi, Ulises; Sudarsky, Daniel

    2000-01-01

    We consider the spacetimes corresponding to static Global Monopoles with interior boundaries corresponding to a Black Hole Horizon and analyze the behavior of the appropriate ADM mass as a function of the horizon radius r_H. We find that for small enough r_H, this mass is negative as in the case of the regular global monopoles, but that for large enough r_H the mass becomes positive encountering an intermediate value for which we have a Black Hole with zero ADM mass.

  12. Black-Hole and White-Hole Horizons in Superfluids

    CERN Document Server

    Volovik, G E

    2006-01-01

    Ripplons -- gravity-capillary waves on the free surface of a liquid or at the interfaces between two superfluids -- are the most favourable excitations for simulation of the general-relativistic effects related to horizons and ergoregions. The white-hole horizon for the ``relativistic'' ripplons at the surface of the shallow liquid is easily simulated using the kitchen-bath hydraulic jump. The same white-hole horizon is observed in quantum liquid -- superfluid 4He. The ergoregion for the ``non-relativistic'' ripplons is generated in the experiments with two sliding 3He superfluids. The common property experienced by all these ripplons is the Miles instability inside the ergoregion or horizon. Because of the universality of the Miles instability, one may expect that it could take place inside the horizon of the astrophysical black holes, if there is a preferred reference frame which comes from the trans-Planckian physics. If this is the case, the black hole would evapotate much faster than due to the Hawking r...

  13. Numerical simulation and experiment analysis of improving permeability by deep-hole presplitting explosion in high gassy and low permeability coal seam

    Institute of Scientific and Technical Information of China (English)

    CAI Feng; LIU Ze-gong; LIN Bai-quan; LI Wei

    2009-01-01

    Created a new damage model for explosive for LS-DYNA3D, taking advantage of the Taylor method aimed at the high gassy and low permeability coal seam, and nu-merically simulated and analyzed the deep-hole presplitting explosion. The entire process of explosion was represented, including cracks caused by dynamic pressure, transmission and vibration superposition of stress waves, as well as cracks growth driven by gas gen-erated by explosion. The influence of the cracks generated in the process of explosion and the performance of improving permeability caused by the difference of interval between explosive holes were analyzed. A reasonable interval between explosive holes of deep-hole presplitting explosions in high gassy and low permeability coal seams was proposed, and the resolution of gas drainage in high gassy and low permeability coal seam was put forward.

  14. From Pinholes to Black Holes

    Energy Technology Data Exchange (ETDEWEB)

    Fenimore, Edward E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-10-06

    Pinhole photography has made major contributions to astrophysics through the use of “coded apertures”. Coded apertures were instrumental in locating gamma-ray bursts and proving that they originate in faraway galaxies, some from the birth of black holes from the first stars that formed just after the big bang.

  15. Improving accuracy of holes honing

    Directory of Open Access Journals (Sweden)

    Ivan М. Buykli

    2015-03-01

    Full Text Available Currently, in precision engineering industry tolerances for linear dimensions and tolerances on shape of surfaces of processing parts are steadily tightened These requirements are especially relevant in processing of holes. Aim of the research is to improve accuracy and to enhance the technological capabilities of holes honing process and, particularly, of blind holes honing. Based on formal logic the analysis of formation of processing errors is executed on the basis of consideration of schemes of irregularity of dimensional wear and tear along the length of the cutting elements. With this, the possibilities of compensating this irregularities and, accordingly, of control of accuracy of processing applied to the honing of both throughout and blind holes are specified. At the same time, a new method of honing is developed, it is protected by the patent of Ukraine for invention. The method can be implemented both on an existing machine tools at insignificant modernization of its system of processing cycle control and on newly designed ones.

  16. Hole localization and symmetry breaking

    NARCIS (Netherlands)

    Broer, R; Nieuwpoort, W.C.

    1999-01-01

    A brief overview is presented of some theoretical work on the symmetry breaking of electronic wavefunctions that followed the early work on Bagus and Schaefer who observed that a considerable lower SCF energy could be obtained for an ionized state of the O2 molecule with a 1s hole if the symmetry re

  17. Black Holes: A Selected Bibliography.

    Science.gov (United States)

    Fraknoi, Andrew

    1991-01-01

    Offers a selected bibliography pertaining to black holes with the following categories: introductory books; introductory articles; somewhat more advanced articles; readings about Einstein's general theory of relativity; books on the death of stars; articles on the death of stars; specific articles about Supernova 1987A; relevant science fiction…

  18. Gravitational Collapse and Black Holes

    Science.gov (United States)

    Ryder, Lewis

    1973-01-01

    The newest and most exotic manner in which stars die is investigated. A brief outline is presented, along with a discussion of the role supernova play, followed by a description of how the black holes originate, exist, and how they might be detected. (DF)

  19. Black holes in brane worlds

    Indian Academy of Sciences (India)

    M S Modgil; S Panda; S Sengupta

    2004-03-01

    A Kerr metric describing a rotating black hole is obtained on the three brane in a five-dimensional Randall-Sundrum brane world by considering a rotating five-dimensional black string in the bulk. We examine the causal structure of this space-time through the geodesic equations.

  20. Black Holes and Exotic Spinors

    Directory of Open Access Journals (Sweden)

    J. M. Hoff da Silva

    2016-05-01

    Full Text Available Exotic spin structures are non-trivial liftings, of the orthogonal bundle to the spin bundle, on orientable manifolds that admit spin structures according to the celebrated Geroch theorem. Exotic spin structures play a role of paramount importance in different areas of physics, from quantum field theory, in particular at Planck length scales, to gravity, and in cosmological scales. Here, we introduce an in-depth panorama in this field, providing black hole physics as the fount of spacetime exoticness. Black holes are then studied as the generators of a non-trivial topology that also can correspond to some inequivalent spin structure. Moreover, we investigate exotic spinor fields in this context and the way exotic spinor fields branch new physics. We also calculate the tunneling probability of exotic fermions across a Kerr-Sen black hole, showing that the exotic term does affect the tunneling probability, altering the black hole evaporation rate. Finally we show that it complies with the Hawking temperature universal law.

  1. Information retrieval from black holes

    CERN Document Server

    Lochan, Kinjalk; Padmanabhan, T

    2016-01-01

    It is generally believed that, when matter collapses to form a black hole, the complete information about the initial state of the matter cannot be retrieved by future asymptotic observers, through local measurements. This is contrary to the expectation from a unitary evolution in quantum theory and leads to (a version of) the black hole information paradox. Classically, nothing else, apart from mass, charge and angular momentum is expected to be revealed to such asymptotic observers after the formation of a black hole. Semi-classically, black holes evaporate after their formation through the Hawking radiation. The dominant part of the radiation is expected to be thermal and hence one cannot know anything about the initial data from the resultant radiation. However, there can be sources of distortions which make the radiation non-thermal. Although the distortions are not strong enough to make the evolution unitary, these distortions carry some part of information regarding the in-state. In this work, we show ...

  2. Implementing black hole as efficient power plant

    CERN Document Server

    Wei, Shao-Wen

    2016-01-01

    Treating the black hole molecules as working substance and considering its phase structure, we study the black hole heat engine by a charged anti-de Sitter black hole. In the reduced temperature-entropy chart, it is found that the work, heat, and efficiency of the engine are independent of the black hole charge. Applying the Rankine cycle with or without a back pressure mechanism to the black hole heat engine, the efficiency is numerically solved. The result shows that the black hole engine working along the Rankine cycle with a back pressure mechanism has a higher efficiency. This provides a novel and efficient mechanism to produce the useful mechanical work with black hole, and such heat engine may act as a possible energy source for the high energy astrophysical phenomena near the black hole.

  3. Astronomy: Intermediate-mass black hole found

    Science.gov (United States)

    Gültekin, Kayhan

    2017-02-01

    The existence of medium-sized black holes has long been debated. Such an object has now been discovered in the centre of a dense cluster of stars, potentially enhancing our understanding of all black holes. See Letter p.203

  4. Regular Black Holes with Cosmological Constant

    Institute of Scientific and Technical Information of China (English)

    MO Wen-Juan; CAI Rong-Gen; SU Ru-Keng

    2006-01-01

    We present a class of regular black holes with cosmological constant Λ in nonlinear electrodynamics. Instead of usual singularity behind black hole horizon, all fields and curvature invariants are regular everywhere for the regular black holes. Through gauge invariant approach, the linearly dynamical stability of the regular black hole is studied. In odd-parity sector, we find that the Λ term does not appear in the master equations of perturbations, which shows that the regular black hole is stable under odd-parity perturbations. On the other hand, for the even-parity sector, the master equations are more complicated than the case without the cosmological constant. We obtain the sufficient conditions for stability of the regular black hole. We also investigate the thermodynamic properties of the regular black hole, and find that those thermodynamic quantities do not satisfy the differential form of first law of black hole thermodynamics. The reason for violating the first law is revealed.

  5. Determining potential for microbial atrazine degradation in agricultural drainage ditches.

    Science.gov (United States)

    Tyler, Heather L; Khalid, Sheza; Jackson, Colin R; Moore, Matthew T

    2013-01-01

    Passage of agricultural runoff through vegetated drainage ditches has been shown to reduce the amount of pesticides, such as atrazine, exiting out of agricultural watersheds. Previous studies have found that microbial communities in soil from fields treated with atrazine display enhanced rates of atrazine degradation. However, no studies have examined the potential for atrazine degradation in ditches used to drain these lands. The purpose of the current study was to determine the potential of the drainage ditch soil microbial community for atrazine degradation. Soil samples were collected from fields and adjacent drainage ditches and from nonagricultural land with no previous exposure to atrazine. Polymerase chain reaction analysis indicated widespread presence of atrazine degradation genes in fields and ditches. Potential for degradation was determined by following the decrease of atrazine in spiked soil samples over a 28-d incubation period. Greater than 95% of atrazine was degraded in field and ditch soils, whereas only 68.5 ± 1.3% was degraded in the nonagricultural control. Comparison with autoclaved soil samples indicated the primary mechanism of atrazine degradation in agricultural soils was microbially mediated, whereas its breakdown in nonagricultural soil appeared to be the byproduct of abiotic processes. Therefore, microbial communities in drainage ditch sediments have the potential to play a role in atrazine removal from agricultural runoff by breaking down atrazine deposited in sediments and limiting the amount of this herbicide carried into downstream ecosystems.

  6. Determining potential for microbial atrazine degradation in agricultural drainage ditches

    Science.gov (United States)

    Passage of agricultural runoff through vegetated drainage ditches has been shown to reduce the amount of pesticides, such as atrazine, exiting agricultural watersheds. Previous studies found that microbial communities in soil from fields treated with atrazine display enhanced rates of atrazine degr...

  7. 7th international conference on acid rock drainage

    Energy Technology Data Exchange (ETDEWEB)

    Barnhisel, R.I. (ed.)

    2006-07-01

    This meeting also serves as the 23rd annual meeting of the American Society of Mining and Reclamation. The papers discussed various aspects of acid mine drainage including its impact, sustainability issues, case studies, lessons learned, characterization, closure/land use issues, emerging technologies, forestry/ecology, abandoned mine lands, modelling, pit lakes/backfill, soils and overburden, and treatment.

  8. Robust options to remove nitrate and phosphate from tile drainage

    NARCIS (Netherlands)

    Jansen, Stefan; Gerritse, Jan; Stuurman, Roelof; Chardon, W.J.; Talens, René

    2016-01-01

    Diffuse emission from agricultural land is a major, persistent source of nitrogen and phosphorus in surface waters. In this contribution, we present field experiments of a series of robust options to remove nitrate and phosphorus at
    field drainage level. Nitrate removal was enhanced by stimulati

  9. Percutaneous biliary drainage in acute suppurative cholangitis with biliary sepsis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyung Lyul; Cho, June Sik; Kwon, Soon Tae; Lee, Sang Jin; Rhee, Byung Chull [Chungnam National University College of Medicine, Daejeon (Korea, Republic of)

    1993-11-15

    Acute suppurative cholangitis is a severe inflammatory process of the bile duct occurred as result of partial or complete obstruction of the bile duct, and may manifest clinically severe form of disease, rapidly deteriorating to life-threatening condition. We analyzed emergency percutaneous transhepatic biliary drainage in 20 patients of acute suppurative cholangitis with biliary sepsis to evaluate the therapeutic effect and complication of the procedure. The underlying cause were 12 benign disease(stones) and eight malignant tumors and among eight malignant tumors, bile duct stones(n=4) and clonorchiasis(n=1) were combined. Percutaneous transhepatic biliary drainage was performed successfully in 17 of 20 patients resulting in improvement of general condition and failed in three patients. The procedure were preterminated due to the patient's condition in two and biliary-proto fistula was developed in one. After biliary decompression by percutaneous transhepatic biliary drainage, effective and successful elective surgery was performed in nine cases, which were seven biliary stones and two biliary cancer with stones. Our experience suggest that emergency percutaneous transhepatic biliary drainage is an initial and effective treatment of choice for acute suppurative cholangitis with sepsis and a safe alternative for nonsurgical treatment.

  10. DETERMINATION OF EFFICIENCY OF THE CIRCUMFERENTIAL DRAINAGE SYSTEM

    Directory of Open Access Journals (Sweden)

    Maciej Kroll

    2015-11-01

    Full Text Available One of the potential alternatives to improve the stability coefficient for an embankment structure is to flatten the filtration curve. As a result, we obtain lower body forces triggering the potential landslide and more advantageous soil strength parameters, which counteract landslide movements. In the case of waste dumps lowering the phreatic surface of waters is achieved thanks to the construction of auxiliary drainage systems, meeting the guidelines for their safe operation. The aim of this paper is to indicate a method facilitating the determination of the actual position of the phreatic surface within the deposited sediments and the assessment of efficiency of the circumferential drainage system in the waste dump. It was decided in this study to apply cone penetration test CPTU. The CPTU made it possible to measure dissipation of excess water pressure in pores identifying drainage conditions, which were compared with the results of piezometric measurements. The results of these tests made it possible to monitor changes in the position of the depression curve of supernatant waters in dams and to determine the efficiency of the circumferential drainage system.

  11. The heat budget of the Ross drainage basin

    NARCIS (Netherlands)

    Oerlemans, J.

    1987-01-01

    Integration of the thermodynamic equation over an entire drainage basin yields a fairly simple expression for the steady-state heat balance. This stems from the fact that dissipative heating can be calculated directly from the release of gravitational energy. When mass balance, surface temperature a

  12. Internal hydraulics of an agricultural drainage denitrification bioreactor

    Science.gov (United States)

    Denitrification bioreactors to reduce the amount of nitrate-nitrogen in agricultural drainage are now being deployed across the U.S. Midwest. However, there are still many unknowns regarding internal hydraulic-driven processes in these "black box" engineered treatment systems. To improve this unders...

  13. Maintenance and Drainage Guidance for the Scott Base Transition, Antarctica

    Science.gov (United States)

    2014-10-01

    12 12 Shake plates and clean off rock help shake dust and mud off vehicles and keep them clean prior to...water drilling to drain the retention ponds ......................................................................... 24 20 Drill sites for drainage...large cuts and chasms of ice melt and erosion will result. In addition, water and melting on the Land Transition results in mud , which invariably ends

  14. Computed tomography diagnosis of partial anomalous pulmonary venous drainage.

    Science.gov (United States)

    Posniak, H V; Dudiak, C M; Olson, M C

    1993-01-01

    A case of the rarely occurring partial anomalous pulmonary venous drainage of the right upper lobe into the azygos arch is presented. Computed tomography (CT) clearly demonstrated the abnormal vessel coursing through the right upper lobe and draining into the azygos arch.

  15. Treating coal mine drainage with an artificial wetland. [USA - Ohio

    Energy Technology Data Exchange (ETDEWEB)

    Fennessy, M.S.; Mitsch, W.J. (Ohio State University Columbus, OH (USA). School of Natural Resources)

    A 0.22-ha constructed wetland dominated by Typha latofolia was evaluated for its ability to treat approximately 340 L/min of coal mine drainage from an underground seep in eastern Ohio. Loading of mine drainage to the wetland ranged from 15 to 35 cm/d. Conductivity, pH, manganese, and sulfate were little changed by the wetland. Iron decreased by 50 to 60%, with slightly higher decreases during the growing season. Comparisons are made to a volunteer Typha marsh receiving mine drainage where iron was found to decrease by approximately 89%. Design considerations of loading rates of created wetlands suggest that improved treatment of mine drainage is correlated with longer retention times and lower iron loading rates. Preliminary design criteria for construction of these types of Typha wetlands for removal of iron are suggested as 5 cm/d hydrologic loading and 2 to 40 g Fe/m{sup 2}.d for iron loading, depending on the treatment desired. 34 refs., 8 figs., 5 tabs.

  16. Sulfate Reduction at Low Ph To Remediate Acid Mine Drainage

    NARCIS (Netherlands)

    Sánchez-Andrea, I.; Sanz, J.L.; Bijmans, M.F.M.; Stams, A.J.M.

    2014-01-01

    Industrial activities and the natural oxidation of metallic sulfide-ores produce sulfate-rich waters with low pH and high heavy metals content, generally termed acid mine drainage (AMD). This is of great environmental concern as some heavy metals are highly toxic. Within a number of possibilities, b

  17. Drainage ditches facilitate frog movements in a hostile landscape

    Science.gov (United States)

    Mazerolle, M.J.

    2005-01-01

    Ditches are common in landscapes influenced by agricultural, forestry, and peat mining activities, and their value as corridors remains unassessed. Pond-breeding amphibians can encounter hostile environments when moving between breeding, summering, or hibernation sites, and are likely to benefit from the presence of ditches in the landscape. Within a system consisting of ditch networks in bogs mined for peat in eastern New Brunswick, Canada, I quantified the breeding, survival, and movements of green frogs (Rana clamitans melanota) in drainage ditches and also surveyed peat fields. Frogs rarely ventured on peat fields and most individuals frequented drainage ditches containing water, particularly in late summer. Though frogs did not breed in ditches, their survival rate in ditches was high (88%). Ditches did not hinder frog movements, as frogs moved independently of the current. Results indicate that drainage ditches containing water enable some movements between habitats isolated by peat mining, in contrast to peat surfaces, and suggest they function as amphibian movement corridors. Thus, such drainage ditches may mitigate the effects of peat extraction on amphibian populations. At the very least, these structures provide an alternative to hostile peat surfaces. This study highlights that small-scale corridors are potentially valuable in population dynamics. ?? Springer 2005.

  18. Runway drainage characteristics related to tire friction performance

    Science.gov (United States)

    Yager, Thomas J.

    1991-01-01

    The capability of a runway pavement to rapidly drain water buildup during periods of precipitation is crucial to minimize tire hydroplaning potential and maintain adequate aircraft ground operational safety. Test results from instrumented aircraft, ground friction measuring vehicles, and NASA Langley's Aircraft Landing Dynamics Facility (ALDF) track have been summarized to indicate the adverse effects of pavement wetness conditions on tire friction performance. Water drainage measurements under a range of rainfall rates have been evaluated for several different runway surface treatments including the transversely grooved and longitudinally grinded concrete surfaces at the Space Shuttle Landing Facility (SLF) runway at NASA Kennedy Space Center in Florida. The major parameters influencing drainage rates and extent of flooding/drying conditions are identified. Existing drainage test data are compared to a previously derived empirical relationship and the need for some modification is indicated. The scope of future NASA Langley research directed toward improving empirical relationships to properly define runway drainage capability and consequently, enhance aircraft ground operational safety, is given.

  19. Drainage water management effects on tile dicharge and water quality

    Science.gov (United States)

    Drainage water management (DWM) has received considerable attention as a potential best management practice for improving water quality in tile drained landscapes. However, only a limited number of studies have documented the effectiveness of DWM in mitigating nitrogen (N) and phosphorus (P) loads. ...

  20. Artificial neural networks as a tool in urban storm drainage

    DEFF Research Database (Denmark)

    Loke, E.; Warnaars, E.A.; Jacobsen, P.

    1997-01-01

    The introduction of Artificial Neural Networks (ANNs) as a tool in the field of urban storm drainage is discussed. Besides some basic theory on the mechanics of ANNs and a general classification of the different types of ANNs, two ANN application examples are presented: The prediction of runoff...

  1. Self-similar solutions for the foam drainage equation

    NARCIS (Netherlands)

    Zitha, P.L.J.; Vermolen, F.J.

    2003-01-01

    The travelling wave solutions of the equation for foam drainage in porous media are developed taking into account the mass conservation criterion. The existence of traveling wave solutions is also discussed. Finally, numerical solutions are obtained using a finite difference scheme together with the

  2. Early and late assessment of internal drainage of chronic dacryocystitis

    NARCIS (Netherlands)

    Mansour, K; Janssen, A. G.; van Bijsterveld, OP

    2003-01-01

    To evaluate the efficacy of internal drainage of a lacrimal abscess, we treated 10 patients with pyocele of the lacrimal sac, who did not want to undergo operative intervention. A temporary nasolacrimal stent was placed in the nasolacrimal duct, and the pussy material was collected for microbiologic

  3. Percutaneous drainage of abscess in the treatment of emphysematous pyelonephritis

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Jin Yong; Jeong, Yong Yeon; Kim, Jae Kyu; Park, Seung Jei; Park, Jin Gyoon; Kang, Heoung Keun [Chonnam Univ. School of Medicine, Kwangju (Korea, Republic of); Roh, Byung Suk [Wonkwang Univ. School of Medicine, Iksan (Korea, Republic of)

    1997-02-01

    To assess the usefulness of percutaneous drainage of abscess in the treatment of emphysematous pyelonephritis. Ten cases of nine patients with emphysematous pyelonephritis were percutaneously drained. All were suffering from diabetes mellitus. The procedure was performed under fluoroscopic guidance in nine cases and US guidance in one case in which bilateral multiloculated abscesses were present in the perirenal space. The results were classified as cure, partial success, recurrence, or failure. The mean drainage period and complication were analyzed. Eight cases were cured, and there was one case success. In one case, who had diffuse renal parenchymal destruction without perirenal fluid collection, the treatment failed. The longest drainage period was 45 days, in a case of re-insertion due to incidental catheter removal; the mean was 23 days. Bacteremia in one case was cured with antibiotic therapy which lasted two days. In diabetic patients, percutaneous drainage of obscess is thought to be a safe and effective method for the treatment of emphysematous pyelonephritis, and is one that does not involve diffuse destruction of renal parenchyma.

  4. Endoscopic Ultrasound-guided Drainage of Pancreatic Pseudocysts

    DEFF Research Database (Denmark)

    Ng, Pui Yung; Nytoft Rasmussen, Ditlev; Vilmann, Peter;

    2013-01-01

    OBJECTIVE: Endoscopic ultrasound (EUS)-guided drainage is a widely used treatment modality for pancreatic pseudocysts (PPC). However, data on the clinical outcome and complication rates are conflicting. Our study aims to evaluate the rates of technical success, treatment success and complications...

  5. Renal lymphangiomatosis during pregnancy: management with percutaneous drainage

    Energy Technology Data Exchange (ETDEWEB)

    Oezmen, M.; Akata, D.; Akhan, O. [Hacettepe Univ., Ankara (Turkey). Dept. of Radiology; Deren, Oe.; Durukan, T. [Hacettepe Univ., Ankara (Turkey). Dept. of Obstetrics and Gynecology; Oezen, H. [Hacettepe Univ., Ankara (Turkey). Dept. of Urology

    2001-01-01

    We report a unique case of exacerbation of renal lymphangiomatosis during pregnancy which was managed percutaneously until delivery. Renal lymphangiomatosis is a very rare benign disorder that might cause abdominal pain and rarely hypertension and hematuria. Surgical treatment options may result in nephrectomy. Percutaneous drainage of symptomatic renal lymphangiomas should be viewed as an efficient therapeutic option particularly when surgery is contraindicated. (orig.)

  6. Temporal abiotic variability structures invertebrate communities in agricultural drainage ditches

    NARCIS (Netherlands)

    Whatley, M.H.; Vonk, J.A.; van der Geest, H.G.; Admiraal, W.

    2015-01-01

    Abiotic variability is known to structure lotic invertebrate communities, yet its influence on lentic invertebrates is not clear. This study tests the hypothesis that variability of nutrients and macro-ions are structuring invertebrate communities in agricultural drainage ditches. This was determine

  7. Oscillatory subglacial drainage in the absence of surface melt

    Directory of Open Access Journals (Sweden)

    C. Schoof

    2013-11-01

    Full Text Available The presence of strong diurnal cycling in basal water pressure records obtained during the melt season is well-established for many glaciers. The behaviour of the drainage system outside the melt season is less well understood. Here we present borehole observations from a surge-type valley glacier in the St Elias Mountains, Yukon Territory, Canada. These indicate the onset of strongly correlated multi-day oscillations in water pressure in multiple boreholes straddling a main drainage axis, starting several weeks after the disappearance of a dominant diurnal mode in August 2011 and persisting until at least January 2012, when multiple data loggers suffered power failure. Jökulhlaups provide a template for understanding spontaneous water pressure oscillations not driven by external supply variability. Using a subglacial drainage model, we show that water pressure oscillations can also be driven on a much smaller scale by the interaction between conduit growth and distributed water storage in smaller water pockets, basal crevasses and moulins, and that oscillations can be triggered when water supply drops below a critical value. We suggest this in combination with a steady background supply of water from groundwater or englacial drainage as a possible explanation for the observed wintertime pressure oscillations.

  8. Information retrieval from black holes

    Science.gov (United States)

    Lochan, Kinjalk; Chakraborty, Sumanta; Padmanabhan, T.

    2016-08-01

    It is generally believed that, when matter collapses to form a black hole, the complete information about the initial state of the matter cannot be retrieved by future asymptotic observers, through local measurements. This is contrary to the expectation from a unitary evolution in quantum theory and leads to (a version of) the black hole information paradox. Classically, nothing else, apart from mass, charge, and angular momentum is expected to be revealed to such asymptotic observers after the formation of a black hole. Semiclassically, black holes evaporate after their formation through the Hawking radiation. The dominant part of the radiation is expected to be thermal and hence one cannot know anything about the initial data from the resultant radiation. However, there can be sources of distortions which make the radiation nonthermal. Although the distortions are not strong enough to make the evolution unitary, these distortions carry some part of information regarding the in-state. In this work, we show how one can decipher the information about the in-state of the field from these distortions. We show that the distortions of a particular kind—which we call nonvacuum distortions—can be used to fully reconstruct the initial data. The asymptotic observer can do this operationally by measuring certain well-defined observables of the quantum field at late times. We demonstrate that a general class of in-states encode all their information content in the correlation of late time out-going modes. Further, using a 1 +1 dimensional dilatonic black hole model to accommodate backreaction self-consistently, we show that observers can also infer and track the information content about the initial data, during the course of evaporation, unambiguously. Implications of such information extraction are discussed.

  9. Continuous Passive Sampling of Solutes from Agricultural Subsurface Drainage Tubes

    Science.gov (United States)

    Lindblad Vendelboe, Anders; de Jonge, Hubert; Rozemeijer, Joachim; Wollesen de Jonge, Lis

    2015-04-01

    Agricultural subsurface tube drain systems play an important role in water and solute transport. One study, focusing on lowland agricultural catchments, showed that subsurface tube drainage contributed up to 80% of the annual discharge and 90% of the annual NO3 load from agricultural fields to the receiving water bodies. Knowledge of e.g. nutrient loads and drainage volumes, based on measurements and modelling, are important for adequate water quality management. Despite the importance of tube drain transport of solutes, monitoring data are scarce. This scarcity is a result of the existing monitoring techniques for flow and contaminant load from tube drains being expensive and labor-extensive. The study presented here aimed at developing a cheap, simple, and robust method to monitor solute loads from tube drains. The method is based on the newly developed Flowcap, which can be attached to existing tube drain outlets and can measure total flow, contaminant load and flow-averaged concentrations of solutes in the drainage. The Flowcap builds on the existing Sorbicell principle, a passive sampling system that measures average concentrations over longer periods of time (days to months) for various compounds. The Sorbicell consists of two compartments permeable to water. One compartment contains an adsorbent and one contains a tracer. When water passes through the Sorbicell the compound of interest is absorbed while a tracer is released. Using the tracer loss to calculate the volume of water that has passed the Sorbicell it is possible to calculate the average concentration of the compound. When mounting Sorbicells in the Flowcap, a flow-proportional part of the drainage is sampled from the main stream. To accommodate the wide range of drainage flow rates two Flowcaps with different capacities were tested in the laboratory: one with a capacity of 25 L min-1 (Q25) and one with a capacity of 256 L min-1 (Q256). In addition, Sorbicells with two different hydraulic

  10. The case for artificial black holes.

    Science.gov (United States)

    Leonhardt, Ulf; Philbin, Thomas G

    2008-08-28

    The event horizon is predicted to generate particles from the quantum vacuum, an effect that bridges three areas of physics--general relativity, quantum mechanics and thermodynamics. The quantum radiation of real black holes is too feeble to be detectable, but black-hole analogues may probe several aspects of quantum black holes. In this paper, we explain in simple terms some of the motivations behind the study of artificial black holes.

  11. Spinning a charged dilaton black hole

    CERN Document Server

    Shiraishi, Kiyoshi

    2015-01-01

    A charged dilaton black hole which possesses infinitesimal angular momentum is studied. We find that the gyromagnetic ratio of the dilaton black hole depends not only on the parameter which appears in the interaction between the dilaton and the electric field but also nonlinearly on the ratio of the charge to the mass of the black hole. The moment of inertia for the charged dilaton hole in the limit of infinitesimal angular momentum is also calculated.

  12. Usefulness of a Biliary Manipulation Catheter in Percutaneous Transhepatic Biliary Drainage

    Energy Technology Data Exchange (ETDEWEB)

    Paek, Auh Whan [Dept. of Radiology, Virginia University Heath Center, Charlottesville (United States); Won, Je Hwan; Lee, Jei Hee; Sun, Joo Sung; Kwak, Kyu Sung; Bae, Jae Ik [Dept. of Radiology, Ajou University School of Medicine, Suwon (Korea, Republic of)

    2011-04-15

    To evaluate usefulness of a manipulation catheter in percutaneous transhepatic biliary drainage (PTBD). A biliary manipulation catheter was used for the aspiration of retained bile and lesion crossing during an initial PTBD in 91 consecutive patients over a 6 month period. This catheter allowed for a 0.035 inch guide wire made of 5F short steel braided polyurethane. The terminal 1 cm segment was tapered and 45 degree angulated. Two side holes were made in the terminal segment to facilitate the aspiration of bile. The safety of this procedure was evaluated based on whether the catheters caused complications during insertion and manipulation, and whether cholangitis was aggravated after the procedure. Effectiveness of the procedure was evaluated based on the ability to aspirate retained bile and to cross the lesion. Both the insertion of a 0.035 inch hydrophilic guide wire and aspiration of sufficient retained bile were successful with the catheter. Crossing the common bile duct (CBD) lesion had a 98.1% success rate during the initial PTBD. Crossing the hilar obstruction lesion was had a 94.7% success rate to the CBD and 92.1% to the contralateral lobe. Cholangitis improved in 97% of cases, and aggravated transiently in only 3% of cases after PTBD.

  13. Non-drainage scleral buckling with solid silicone elements

    Directory of Open Access Journals (Sweden)

    Pukhraj Rishi

    2014-01-01

    Full Text Available Background: With the increasing number of cataract surgeries, incidence of posterior segment complications including rhegmatogenous retinal detachment (RRD is likely to rise. Scleral buckling (SB surgery is an effective and less expensive option. The primary advantage of non-drainage procedure is avoidance of possible complications associated with trans-choroidal drainage. The aim of present study is to describe the clinical profile of subjects undergoing non-drainage SB surgery with solid silicone elements for RRD and analyze their treatment outcomes. Materials and Methods: This was a retrospective, non-randomized, interventional study at a tertiary care center. Three hundred and six eyes of 298 patients undergoing non-drainage SB surgery with solid silicone elements from year 2000 to 2006 were included. Inclusion criteria were primary RRD, peripheral depressible retinal break, media clarity affording peripheral retinal view and proliferative vitreo-retinopathy (PVR up to grade C2. Uni- and multivariate analyses was done to analyze factors affecting anatomical and visual outcomes. Statistical analysis was performed using SPSS Version 10. Results: Mean follow-up was 303 ± 393.33 days. Primary anatomical success was obtained in 279 (91.2% eyes; primary functional success in 286 (93.5% eyes. PVR (grade B or C, intraocular pressure <10 mm Hg and the inability to find a retinal break were significantly associated with final anatomical failure. Baseline vision ≤3/60 was significantly associated with poor visual recovery. Conclusions: SB surgery is reasonably safe and highly efficacious. Solid silicone elements are effective in non-drainage SB surgery. However, case selection is important.

  14. Modeling Antarctic subglacial lake filling and drainage cycles

    Directory of Open Access Journals (Sweden)

    C. F. Dow

    2015-11-01

    Full Text Available The growth and drainage of active subglacial lakes in Antarctica has previously been inferred from analysis of ice surface altimetry data. We use a subglacial hydrology model applied to a synthetic Antarctic ice stream to determine internal controls on the filling and drainage of subglacial lakes and their impact on ice stream dynamics. Our model outputs suggest that the highly constricted subglacial environment of the ice stream, combined with relatively high rates of water flow funneled from large catchments, can combine to create a system exhibiting slow-moving pressure waves. Over a period of years, the accumulation of water in the ice stream onset region results in a buildup of pressure creating temporary channels, which then evacuate the excess water. This increased flux of water through the ice stream drives lake growth. As the water body builds up, it too steepens the hydraulic gradient and allows greater flux out of the overdeepened lake basin. Eventually this flux is large enough to create channels that cause the lake to drain. Due to the presence of the channels, the drainage of the lake causes high water pressures around 50 km downstream of the lake rather than immediately in the vicinity of the overdeepening. Following lake drainage, channels again shut down. Lake drainage depends on the internal hydrological development in the wider system and therefore does not directly correspond to a particular water volume or depth. This creates a highly temporally and spatially variable system, which is of interest for assessing the importance of subglacial lakes in ice stream hydrology and dynamics.

  15. A note on the black hole remnant

    OpenAIRE

    Xiang, Li

    2006-01-01

    Analyzing the tunneling probability of a Schwarzschild black hole with a negative log-area correction to Bekenstein-Hawking entropy, I argue that this correction may be closely related to a black hole remnant. The value for the minimal black hole mass is also discussed.

  16. Straight hole drilling machines for coal mines

    Science.gov (United States)

    Timonin, VV; Kokoulin, DI; Alekseev, SE; Kubanychbek, B.

    2017-02-01

    The authors prove the demand for drilling machines capable of making long straight holes in rocks with the strength up to 120 MPa. The paper describes the designed, manufactured and tested down-the-hole hammers for rotary–percussion drilling of long straight directional holes. The hammers have been delivered to Berezovskaya Mine for further trial and commercial operation.

  17. Signatures of black holes at the LHC

    Science.gov (United States)

    Cavaglià, Marco; Godang, Romulus; Cremaldi, Lucien M.; Summers, Donald J.

    2007-06-01

    Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.

  18. Signatures of black holes at the LHC

    CERN Document Server

    Cavaglia, Marco; Cremaldi, Lucien M; Summers, Donald J

    2007-01-01

    Signatures of black hole events at CERN's Large Hadron Collider are discussed. Event simulations are carried out with the Fortran Monte Carlo generator CATFISH. Inelasticity effects, exact field emissivities, color and charge conservation, corrections to semiclassical black hole evaporation, gravitational energy loss at formation and possibility of a black hole remnant are included in the analysis.

  19. Event horizons of two Schwarzchild black holes

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, N.T.

    1988-06-01

    The problem of two Schwarzchild black holes, one much smaller than the other, is investigated by an approximate analytic method. The critical separation between the black holes at which their event horizons join is found for two cases, (2) time-symmetric initial data, and (b) the small black hole falls from rest at infinity.

  20. Resource Letter BH-1: Black Holes.

    Science.gov (United States)

    Detweiler, Steven

    1981-01-01

    Lists resources on black holes, including: (1) articles of historical interest; (2) books and journal articles on elementary expositions; (3) elementary and advanced textbooks; and (4) research articles on analytic structure of black holes, black hole dynamics, and astrophysical processes. (SK)

  1. Extremal black holes in N=2 supergravity

    NARCIS (Netherlands)

    Katmadas, S.

    2011-01-01

    An explanation for the entropy of black holes has been an outstanding problem in recent decades. A special case where this is possible is that of extremal black holes in N=2 supergravity in four and five dimensions. The best developed case is for black holes preserving some supersymmetry (BPS), whic

  2. Compensating Scientism through "The Black Hole."

    Science.gov (United States)

    Roth, Lane

    The focal image of the film "The Black Hole" functions as a visual metaphor for the sacred, order, unity, and eternal time. The black hole is a symbol that unites the antinomic pairs of conscious/unconscious, water/fire, immersion/emersion, death/rebirth, and hell/heaven. The black hole is further associated with the quest for…

  3. High precision, rapid laser hole drilling

    Science.gov (United States)

    Chang, Jim J.; Friedman, Herbert W.; Comaskey, Brian J.

    2013-04-02

    A laser system produces a first laser beam for rapidly removing the bulk of material in an area to form a ragged hole. The laser system produces a second laser beam for accurately cleaning up the ragged hole so that the final hole has dimensions of high precision.

  4. On Quantum Contributions to Black Hole Growth

    NARCIS (Netherlands)

    Spaans, M.

    2013-01-01

    The effects of Wheeler’s quantum foam on black hole growth are explored from an astrophysical per- spective. Quantum fluctuations in the form of mini (10−5 g) black holes can couple to macroscopic black holes and allow the latter to grow exponentially in mass on a time scale of 109 years. Consequent

  5. Micro black holes in the laboratory

    CERN Document Server

    Bleicher, Marcus; Sprenger, Martin; Winstanley, Elizabeth

    2011-01-01

    The possibility of creating microscopic black holes is one of the most exciting predictions for the LHC, with potentially major consequences for our current understanding of physics. We briefly review the theoretical motivation for micro black hole production, and our understanding of their subsequent evolution. Recent work on modelling the radiation from quantum-gravity-corrected black holes is also discussed.

  6. 30 CFR 77.1010 - Collaring holes.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Collaring holes. 77.1010 Section 77.1010 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... Control § 77.1010 Collaring holes. (a) Starter steels shall be used when collaring holes with...

  7. Charged Black Holes in New Massive Gravity

    OpenAIRE

    Ghodsi, Ahmad; Moghadassi, Mohammad

    2010-01-01

    We construct charged black hole solutions to three-dimensional New Massive Gravity (NMG), by adding electromagnetic Maxwell and Chern-Simons actions. We find charged black holes in the form of warped AdS_3 and "log" solutions in specific critical point. The entropy, mass and angular momentum of these black holes are computed.

  8. The fuzzball proposal for black holes

    NARCIS (Netherlands)

    Skenderis, K.; Taylor, M.

    2008-01-01

    The fuzzball proposal states that associated with a black hole of entropy S, there are expS horizon-free non-singular solutions that asymptotically look like the black hole but generically differ from the black hole up to the horizon scale. These solutions, the fuzzballs, are considered to be the bl

  9. Compensating Scientism through "The Black Hole."

    Science.gov (United States)

    Roth, Lane

    The focal image of the film "The Black Hole" functions as a visual metaphor for the sacred, order, unity, and eternal time. The black hole is a symbol that unites the antinomic pairs of conscious/unconscious, water/fire, immersion/emersion, death/rebirth, and hell/heaven. The black hole is further associated with the quest for transcendent…

  10. Shapes and Positions of Black Hole Shadows in Accretion Disks and Spin Parameters of Black Holes

    OpenAIRE

    Takahashi, Rohta

    2004-01-01

    Can we determine a spin parameter of a black hole by observation of a black hole shadow in an accretion disk? In order to answer this question, we make a qualitative analysis and a quantitative analysis of a shape and a position of a black hole shadow casted by a rotating black hole on an optically thick accretion disk and its dependence on an angular momentum of a black hole. We have found black hole shadows with a quite similar size and a shape for largely different black hole spin paramete...

  11. The stable problem of the black-hole connected region in the Schwarzschild black hole

    OpenAIRE

    Tian, Guihua

    2005-01-01

    The stability of the Schwarzschild black hole is studied. Using the Painlev\\'{e} coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequen...

  12. Systematic review and meta-analysis of closed suction drainage versus non-drainage in primary hip arthroplasty.

    LENUS (Irish Health Repository)

    Kelly, Enda G

    2014-03-01

    The routine use of drains in surgery has been dogmatically instituted in some disciplines. Orthopaedic surgery is one such sub-speciality. The use of postoperative closed suction drainage in total hip arthroplasty (THA) has become increasingly controversial with multiple randomised control trials performed to assess the benefit to outcome in THA. The hypothesis of this systematic review is that closed suction drainage does not infer a benefit and increase transfusion requirements of primary total hip arthroplasty patients. A systematic review and meta-analysis was conducted adhering to the PRISMA guidelines. A search of the available literature was performed on PubMed, Cochrane Central Registry of Controlled Trials, MEDLINE (OVID) and EMBASE using a combination of MeSH terms and Boolean operators. All data analysis was performed using the Cochrane Collaboration\\'s Review Manager 5.1. Sixteen studies (n=2705) were included in the analysis. Post-operative closed suction drainage was found to increase total blood loss and blood transfusion requirements (p<0.05). Surgical site infection demonstrated no significant difference between the two groups (p=0.82). No significant difference in haematoma formation between groups (p=0.19) was elicited. The routine use of closed suction drainage systems post primary hip arthroplasty is not supported by this meta-analysis. However, the heterogeneity between studies does limit the accuracy of the meta-analysis.

  13. Systematic review and meta-analysis of closed suction drainage versus non-drainage in primary hip arthroplasty.

    Science.gov (United States)

    Kelly, Enda G; Cashman, James P; Imran, Farrah H; Conroy, Ronán; O'Byrne, John

    2014-03-01

    The routine use of drains in surgery has been dogmatically instituted in some disciplines. Orthopaedic surgery is one such sub-speciality. The use of postoperative closed suction drainage in total hip arthroplasty (THA) has become increasingly controversial with multiple randomised control trials performed to assess the benefit to outcome in THA. The hypothesis of this systematic review is that closed suction drainage does not infer a benefit and increase transfusion requirements of primary total hip arthroplasty patients. A systematic review and meta-analysis was conducted adhering to the PRISMA guidelines. A search of the available literature was performed on PubMed, Cochrane Central Registry of Controlled Trials, MEDLINE (OVID) and EMBASE using a combination of MeSH terms and Boolean operators. All data analysis was performed using the Cochrane Collaboration's Review Manager 5.1. Sixteen studies (n=2705) were included in the analysis. Post-operative closed suction drainage was found to increase total blood loss and blood transfusion requirements (psuction drainage systems post primary hip arthroplasty is not supported by this meta-analysis. However, the heterogeneity between studies does limit the accuracy of the meta-analysis.

  14. Visual drainage assessment: A standardised visual soil assessment method for use in land drainage design in Ireland

    Directory of Open Access Journals (Sweden)

    Tuohy P.

    2016-06-01

    Full Text Available The implementation of site-specific land drainage system designs is usually disregarded by landowners in favour of locally established ‘standard practice’ land drainage designs. This is due to a number of factors such as a limited understanding of soil–water interactions, lack of facilities for the measurement of soil’s physical or hydrological parameters and perceived time wastage and high costs. Hence there is a need for a site-specific drainage system design methodology that does not rely on inaccessible, time-consuming and/or expensive measurements of soil physical or hydrological properties. This requires a standardised process for deciphering the drainage characteristics of a given soil in the field. As an initial step, a new visual soil assessment method, referred to as visual drainage assessment (VDA, is presented whereby an approximation of the permeability of specific soil horizons is made using seven indicators (water seepage, pan layers, texture, porosity, consistence, stone content and root development to provide a basis for the design of a site-specific drainage system. Across six poorly drained sites (1.3 ha to 2.6 ha in size in south-west Ireland a VDA-based design was compared with (i an ideal design (utilising soil physical measurements to elucidate soil hydraulic parameters and (ii a standard design (0.8 m deep drains at a 15 m spacing by model estimate of water table control and rainfall recharge/drain discharge capacity. The VDA method, unlike standard design equivalents, provided a good approximation of an ideal (from measured hydrological properties design and prescribed an equivalent land drainage system in the field. Mean modelled rainfall recharge/drain discharge capacity for the VDA (13.3 mm/day and ideal (12.0 mm/day designs were significantly higher (P < 0.001, s.e. 1.42 mm/day than for the standard designs (0.5 mm/day, when assuming a design minimum water table depth of 0.45 m.

  15. Drainage of the ice-dammed Lake Tinninilik, West Greenland; implication on bedrock uplift

    DEFF Research Database (Denmark)

    Kjeldsen, Kristian Kjellerup; Khan, Shfaqat Abbas; Bjørk, Anders Anker;

    Drainage of ice-dammed lakes is regularly observed along the margin of the Greenland Ice Sheet. However, the speed of the drainage events and implications can vary depending on the size of the lakes and the local settings. Here, we assess the drainage pattern of Lake Tinninilik, dammed...

  16. Integration of Drainage, Water Quality and Flood Management in Rural, Urban and Lowland Areas

    NARCIS (Netherlands)

    Vlotman, W.F.; Wong, T.; Schultz, E.

    2007-01-01

    Managing drainage in rural and peri-urban environments has become an essential part of integrated water management. Drainage has become a science of control, storage and (re)use while meeting triple bottom-line requirements (environment, social and economic assessments). Controlled drainage in rural

  17. Assessment and synthesis of 50 years of published drainage phosphorus losses

    Science.gov (United States)

    The prevalence of artificial drainage systems in intensively cropped areas across North America combined with the importance of freshwater resources in these regions has created a critical intersection where understanding drainage phosphorus (P) transport is vital. In this study, drainage nutrient ...

  18. Population genetics of invasive common carp Cyprinus carpio L. in coastal drainages in eastern Australia.

    Science.gov (United States)

    Haynes, G D; Gilligan, D M; Grewe, P; Moran, C; Nicholas, F W

    2010-10-01

    The common carp Cyprinus carpio introduced in two drainages in eastern Australia are largely descended from European common carp, and in a third drainage they descend largely from East Asian common carp. The partial genetic differentiation among the species in those drainages is consistent with their origins.

  19. Etheostoma erythrozonum, a new species of darter (teleostei: Percidae) from the Meramec River drainage, missouri

    Science.gov (United States)

    Switzer, J.F.; Wood, R.M.

    2009-01-01

    A new species of darter, Etheostoma erythrozonum, is described from the Meramec River drainage of Missouri, USA. Etheostoma erythrozonum is the first known fish species endemic to the Meramec River drainage. It differs morphologically and genetically from populations of its sister species, Etheostoma tetrazonum, from the Gasconade River, Osage River, and Moreau River drainages. Copyright ?? 2009 ?? Magnolia Press.

  20. 46 CFR 116.1120 - Drainage of cockpit vessels, well deck vessels, and open boats.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Drainage of cockpit vessels, well deck vessels, and open boats. 116.1120 Section 116.1120 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL... Drainage of cockpit vessels, well deck vessels, and open boats. Drainage of cockpit vessels, well...

  1. 46 CFR 178.450 - Calculation of drainage area for cockpit and well deck vessels.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Calculation of drainage area for cockpit and well deck....450 Calculation of drainage area for cockpit and well deck vessels. (a) The drainage area required on... cockpit deck; DR=total deck area of the cockpit or well deck in the after 2/3 of the vessel length...

  2. Best options for preoperative biliary drainage in patients with Klatskin tumors.

    Science.gov (United States)

    Jo, Jung Hyun; Chung, Moon Jae; Han, Dai Hoon; Park, Jeong Youp; Bang, Seungmin; Park, Seung Woo; Song, Si Young; Chung, Jae Bock

    2017-01-01

    Operative treatment combined with PBD has been established as a safe management strategy for Klatskin tumors. However, controversy exists regarding the preferred technique for PBD among percutaneous transhepatic biliary drainage (PTBD), endoscopic biliary stenting (EBS), and endoscopic nasobiliary drainage (ENBD). This study aimed to identify the best technique for preoperative biliary drainage (PBD) in Klatskin tumor patients.

  3. Dyonic Non-Abelian Black Holes

    CERN Document Server

    Brihaye, Y; Kunz, J; Tell, N

    1999-01-01

    We study static spherically symmetric dyonic black holes in Einstein-Yang-Mills-Higgs theory. As for the magnetic non-abelian black holes, the domain of existence of the dyonic non-abelian black holes is limited with respect to the horizon radius and the dimensionless coupling constant $\\alpha$, which is proportional to the ratio of vector meson mass and Planck mass. At a certain critical value of this coupling constant, $\\hat \\alpha$, the maximal horizon radius is attained. We derive analytically a relation between $\\hat numerically. Besides the fundamental dyonic non-abelian black holes, we study radially excited dyonic non-abelian black holes and globally regular gravitating dyons.

  4. Black Hole Decay as Geodesic Motion

    CERN Document Server

    Sen-Gupta, K; Gupta, Kumar S.; Sen, Siddhartha

    2003-01-01

    We show that a formalism for analyzing the near-horizon conformal symmetry of Schwarzschild black holes using a scalar field probe is capable of describing black hole decay. The decay rate is shown to be correctly described by geodesic motion in the space of black hole masses. This provides a novel geometric interpretation for the decay of black holes. We also show that the near-horizon conformal symmetry predicts a precise correction term to the usual expression for the decay rate of black holes. The results obtained here are a consequence of the holographic nature of the system.

  5. An Optical Analog of a Black Holes

    CERN Document Server

    Royston, A; Royston, Andrew; Gass, Richard

    2002-01-01

    Using media with extremely low group velocities one can create an optical analog of a curved space-time. Leonhardt and Piwnicki have proposed that a vortex flow will act as an optical black hole. We show that although the Leonhardt - Piwnicki flow has an orbit of no return and an infinite red-shift surface, it is not a true black hole since it lacks a null hypersurface. However a radial flow will produce a true optical black hole that has a Hawking temperature and obeys the first law of black hole mechanics. By combining the Leonhardt - Piwnicki flow with a radial flow we obtain the analog of the Kerr black hole.

  6. Black Hole Radiation and Volume Statistical Entropy

    CERN Document Server

    Rabinowitz, M

    2005-01-01

    The simplest possible equations for Hawking radiation, and other black hole radiated power is derived in terms of black hole density. Black hole density also leads to the simplest possible model of a gas of elementary constituents confined inside a gravitational bottle of Schwarzchild radius at tremendous pressure, which yields identically the same functional dependence as the traditional black hole entropy. Variations of Sbh are can be obtained which depend on the occupancy of phase space cells. A relation is derived between the constituent momenta and the black hole radius RH

  7. Black holes under external influence

    Indian Academy of Sciences (India)

    Jiří Bičák

    2000-10-01

    The work on black holes immersed in external fields is reviewed in both test-field approximation and within exact solutions. In particular we pay attention to the effect of the expulsion of the flux of external fields across charged and rotating black holes which are approaching extremal states. Recently this effect has been shown to occur for black hole solutions in string theory. We also discuss black holes surrounded by rings and disks and rotating black holes accelerated by strings.

  8. On coupling impedances of pumping holes

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S.

    1993-04-01

    Coupling impedances of a single small hole in vacuum-chamber walls have been calculated at low frequencies. To generalize these results for higher frequencies and/or larger holes one needs to solve coupled integral equations for the effective currents. These equations are solved for two specific hole shapes. The effects of many holes at high frequencies where the impedances are not additive are studied using a perturbation-theory method. The periodic versus random distributions of the pumping holes in the Superconducting Super Collider liner are compared.

  9. Ampullary carcinoma: Effect of preoperative biliary drainage on surgical outcome

    Institute of Scientific and Technical Information of China (English)

    Sheikh Anwar Abdullah; Tarun Gupta; Khairul Azhar Jaafar; Yaw Fui Alexander Chung; London Lucien Peng Jin Ooi; Steven Joseph Mesenas

    2009-01-01

    AIM: To evaluate the influence of preoperative biliary drainage on morbidity and mortality after surgical resection for ampullary carcinoma. METHODS: We analyzed retrospectively data for 82 patients who underwent potentially curative surgery for ampullary carcinoma between September 1993 and July 2007 at the Singapore General Hospital, a tertiary referral hospital. Diagnosis of ampullary carcinoma was confirmed histologically. Thirty-five patients underwent preoperative biliary drainage (PBD group), and 47 were not drained (non-PBD group). The mode of biliary drainage was endoscopic retrograde cholangiopancreatography ( n = 33) or percutaneous biliary drainage ( n = 2). The following parameters were analyzed: wound infection, intra-abdominal abscess, intra-abdominal or gastrointestinal bleeding, septicemia, biliary or pancreatic leakage, pancreatitis, gastroparesis, and re-operation rate. Mortality was assessed at 30 d (hospital mortality) and also longterm. The statistical endpoint of this study was patient survival after surgery. RESULTS: The groups were wel l matched for demographic criteria, clinical presentation and operative characteristics, except for lower hemoglobin in the non- PBD group (10.9 ± 1.6 vs 11.8 ± 1.6 in the PBD group). group (10.9 ± 1.6 vs 11.8 ± 1.6 in the PBD group). Of the parameters assessing postoperative morbidity, incidence of wound infection was significantly less in the PBD than the non-PBD group [1 (2.9%) vs 12 (25.5%)]. However, the rest of the parameters did not differ significantly between the groups, i.e. sepsis [10 (28.6%) vs 14 (29.8%)], intra-abdominal bleeding [1 (2.9%) vs 5 (10.6%)], intra-abdominal abscess [1 (2.9%) vs 8 (17%)], gastrointestinal bleeding [3 (8.6%) vs 5 (10.6%)], pancreatic leakage [2 (5.7%) vs 3 (6.4%)], biliary leakage [2 (5.7%) vs 3 (6.4%)], pancreatitis [2 (5.7%) vs 2 (4.3%)], gastroparesis [6 (17.1%) vs 10 (21.3%)], need for blood transfusion [10 (28.6%) vs 17 (36.2%)] and re-operation rate [1 (2

  10. Black Holes Shed Light on Galaxy Formation

    Science.gov (United States)

    2000-01-01

    This videotape is comprised of several segments of animations on black holes and galaxy formation, and several segments of an interview with Dr. John Kormendy. The animation segments are: (1) a super massive black hole, (2) Centarus A active black hole found in a collision, (3) galaxy NGC-4261 (active black hole and jet model), (4) galaxy M-32 (orbits of stars are effected by the gravity of the black hole), (5) galaxy M-37 (motion of stars increases as mass of black hole increases), (6) Birth of active galactic nuclei, (7) the collision of two galaxy leads to merger of the black holes, (8) Centarus A and simulation of the collision of 2 galaxies. There are also several segments of an interview with John Kormendy. In these segments he discusses the two most important aspects of his recent black hole work: (1) the correlations between galaxies speed and the mass of the black holes, and (2) the existence of black holes and galactic formation. He also discusses the importance of the Hubble Space Telescope and the Space Telescope Imaging Spectrograph to the study of black holes. He also shows the methodology of processing images from the spectrograph in his office.

  11. Black Holes with Proca Hair

    CERN Document Server

    Fan, Zhong-Ying

    2016-01-01

    In this paper, we consider Einstein gravity coupled to a Proca field, either minimally or non-minimally, together with a vector potential of the type $V=2\\Lambda_0+ m^2 A^2/2 + \\gamma_4 A^4$. For a simpler non-minimally coupled theory with $\\Lambda_0=m=\\gamma_4=0$, we obtain both extremal and non-extremal black hole solutions that are asymptotic to Minkowski space-times. We study the global properties of the solutions and derive the first law of thermodynamics using Wald formalism. We find that the thermodynamical first laws of the extremal black holes are modified by a one form associated with the Proca. In particular, due to the existence of the non-minimal coupling, the Proca forms thermodynamic conjugates with the graviton mode and partly contributes to the one form modifying the first laws. For a minimally coupled theory with $\\Lambda_0\

  12. "Twisted" black holes are unphysical

    CERN Document Server

    Gray, Finnian; Schuster, Sebastian; Visser, Matt

    2016-01-01

    So-called "twisted" black holes have recently been proposed by Zhang (1609.09721 [gr-qc]), and further considered by Chen and Jing (1610.00886 [gr-qc]), and more recently by Ong (1610.05757 [gr-qc]). While these spacetimes are certainly Ricci-flat, and so mathematically satisfy the vacuum Einstein equations, they are also merely minor variants on Taub--NUT spacetimes. Consequently they exhibit several unphysical features that make them quite unreasonable as realistic astrophysical objects. Specifically, these "twisted" black holes are not (globally) asymptotically flat. Furthermore, they contain closed timelike curves that are not hidden behind any event horizon --- the most obvious of these closed timelike curves are small azimuthal circles around the rotation axis, but the effect is more general. The entire region outside the horizon is infested with closed timelike curves.

  13. Black Hole with Quantum Potential

    CERN Document Server

    Ali, Ahmed Farag

    2015-01-01

    In this work, we investigate black hole (BH) physics in the context of quantum corrections. These quantum corrections were introduced recently by replacing classical geodesics with quantal (Bohmian) trajectories and hence form a quantum Raychaudhuri equation (QRE). From the QRE, we derive a modified Schwarzschild metric, and use that metric to investigate BH singularity and thermodynamics. We find that these quantum corrections change the picture of Hawking radiation greatly when the size of BH approaches the Planck scale. They prevent the BH from total evaporation, predicting the existence of a quantum BH remnant, which introduces a possible resolution for the catastrophic behavior of Hawking radiation as the BH mass approaches zero. It also ameliorates the black hole singularity and the information loss problem.

  14. Black hole with quantum potential

    Directory of Open Access Journals (Sweden)

    Ahmed Farag Ali

    2016-08-01

    Full Text Available In this work, we investigate black hole (BH physics in the context of quantum corrections. These quantum corrections were introduced recently by replacing classical geodesics with quantal (Bohmian trajectories and hence form a quantum Raychaudhuri equation (QRE. From the QRE, we derive a modified Schwarzschild metric, and use that metric to investigate BH singularity and thermodynamics. We find that these quantum corrections change the picture of Hawking radiation greatly when the size of BH approaches the Planck scale. They prevent the BH from total evaporation, predicting the existence of a quantum BH remnant, which may introduce a possible resolution for the catastrophic behavior of Hawking radiation as the BH mass approaches zero. Those corrections also turn the spacelike singularity of the black hole to be timelike, and hence this may ameliorate the information loss problem.

  15. Black Holes at the LHC

    CERN Document Server

    Kanti, Panagiota

    2008-01-01

    In these two lectures, we will address the topic of the creation of small black holes during particle collisions in a ground-based accelerator, such as LHC, in the context of a higher-dimensional theory. We will cover the main assumptions, criteria and estimates for their creation, and we will discuss their properties after their formation. The most important observable effect associated with their creation is likely to be the emission of Hawking radiation during their evaporation process. After presenting the mathematical formalism for its study, we will review the current results for the emission of particles both on the brane and in the bulk. We will finish with a discussion of the methodology that will be used to study these spectra, and the observable signatures that will help us identify the black-hole events.

  16. Black holes in magnetic monopoles

    Science.gov (United States)

    Lee, Kimyeong; Nair, V. P.; Weinberg, Erick J.

    1992-04-01

    We study magnetically charged classical solutions of a spontaneously broken gauge theory interacting with gravity. We show that nonsingular monopole solutions exist only if the Higgs-field vacuum expectation value v is less than or equal to a critical value vcr, which is of the order of the Planck mass. In the limiting case, the monopole becomes a black hole, with the region outside the horizon described by the critical Reissner-Nordström solution. For vsolutions which are singular at r=0, but which have this singularity hidden within a horizon. These have nontrivial matter fields outside the horizon, and may be interpreted as small black holes lying within a magnetic monopole. The nature of these solutions as a function of v and of the total mass M and their relation to the Reissner-Nordström solutions are discussed.

  17. Black Holes in Magnetic Monopoles

    CERN Document Server

    Lee, K; Weinberg, Erick J; Weinberg, Erick J.

    1992-01-01

    We study magnetically charged classical solutions of a spontaneously broken gauge theory interacting with gravity. We show that nonsingular monopole solutions exist only if the Higgs vacuum expectation value $v$ is less than or equal to a critical value $v_{cr}$, which is of the order of the Planck mass. In the limiting case the monopole becomes a black hole, with the region outside the horizon described by the critical Reissner-Nordstrom solution. For $v

  18. Extremal Black Holes as Qudits

    CERN Document Server

    Rios, Michael

    2011-01-01

    We extend the black hole/qudit correspondence by identifying five and six-dimensional 1/2-BPS black string and hole charge vectors in N=8 and N=2 magic supergravities with qubits and qutrits over composition algebras. In D=6, this is accomplished via Hopf fibrations, which map qubits over composition algebras to rank one elements of Jordan algebras of degree two. An analogous procedure maps qutrits over composition algebras to D=5 charge vectors, which are rank one elements of Jordan algebras of degree three. In both cases, the U-duality groups are interpreted as qudit SLOCC transformation groups. We provide explicit gates for such transformations and study their applications in toroidally compactified M-theory.

  19. Black hole with quantum potential

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Ahmed Farag, E-mail: ahmed.ali@fsc.bu.edu.eg [Department of Physics, Faculty of Science, Benha University, Benha 13518 (Egypt); Khalil, Mohammed M., E-mail: moh.m.khalil@gmail.com [Department of Electrical Engineering, Alexandria University, Alexandria 12544 (Egypt)

    2016-08-15

    In this work, we investigate black hole (BH) physics in the context of quantum corrections. These quantum corrections were introduced recently by replacing classical geodesics with quantal (Bohmian) trajectories and hence form a quantum Raychaudhuri equation (QRE). From the QRE, we derive a modified Schwarzschild metric, and use that metric to investigate BH singularity and thermodynamics. We find that these quantum corrections change the picture of Hawking radiation greatly when the size of BH approaches the Planck scale. They prevent the BH from total evaporation, predicting the existence of a quantum BH remnant, which may introduce a possible resolution for the catastrophic behavior of Hawking radiation as the BH mass approaches zero. Those corrections also turn the spacelike singularity of the black hole to be timelike, and hence this may ameliorate the information loss problem.

  20. Quasistars: Accreting black holes inside massive envelopes

    CERN Document Server

    Begelman, Mitchell C; Armitage, Philip J

    2007-01-01

    We study the structure and evolution of "quasistars," accreting black holes embedded within massive hydrostatic gaseous envelopes. These configurations may model the early growth of supermassive black hole seeds. The accretion rate onto the black hole adjusts so that the luminosity carried by the convective envelope equals the Eddington limit for the total mass. This greatly exceeds the Eddington limit for the black hole mass alone, leading to rapid growth of the black hole. We use analytic models and numerical stellar structure calculations to study the structure and evolution of quasistars. We derive analytically the scaling of the photospheric temperature with the black hole mass and envelope mass, and show that it decreases with time as the black hole mass increases. Once the photospheric temperature becomes lower than 10000 K, the photospheric opacity drops precipitously and the photospheric temperature hits a limiting value, analogous to the Hayashi track for red giants and protostars, below which no hy...

  1. Plasma electron-hole kinematics: momentum conservation

    CERN Document Server

    Hutchinson, I H

    2016-01-01

    We analyse the kinematic properties of a plasma electron hole: a non-linear self-sustained localized positive electric potential perturbation, trapping electrons, that behaves as a coherent entity. When a hole accelerates or grows in depth, ion and electron plasma momentum is changed both within the hole and outside it, by an energization process we call jetting. We present a comprehensive analytic calculation of the momentum changes of an isolated general one-dimensional hole. The conservation of the total momentum gives the hole's kinematics, determining its velocity evolution. Our results explain many features of the behavior of hole speed observed in numerical simulations, including self-acceleration at formation, and hole pushing and trapping by ion streams.

  2. From Schwinger Balls to Black Holes

    CERN Document Server

    Allahbakhshi, Davood

    2016-01-01

    We have shown intriguing similarities between Schwinger balls and black holes. By considering black hole as a gravitational Schwinger ball, we have derived the Bekenstein-Hawking entropy and the first law of black hole thermodynamics as a direct result of the inverse area dependence of the gravitational force. It is also shown that the Planck length is nothing but the gravitational Schwinger length. The relation between the mass and the radius of the black hole is derived by considering the black hole as a Schwinger ball of gravitons. We show how the evolution of the entanglement entropy of the black hole, as Page introduced many years ago, can be obtained by including gravitons in the black hole's evaporation process and using a deformed EPR mechanism. Also this deformed EPR mechanism can solve the information paradox. We show how naive simultaneous usage of Page's argument and equivalence principle leads to firewall problem.

  3. Complexity, Action, and Black Holes

    CERN Document Server

    Brown, Adam; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2015-01-01

    Our earlier paper "Complexity Equals Action" conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the `Wheeler-DeWitt' patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are fastest computers in nature.

  4. Complexity, action, and black holes

    Science.gov (United States)

    Brown, Adam R.; Roberts, Daniel A.; Susskind, Leonard; Swingle, Brian; Zhao, Ying

    2016-04-01

    Our earlier paper "Complexity Equals Action" conjectured that the quantum computational complexity of a holographic state is given by the classical action of a region in the bulk (the "Wheeler-DeWitt" patch). We provide calculations for the results quoted in that paper, explain how it fits into a broader (tensor) network of ideas, and elaborate on the hypothesis that black holes are the fastest computers in nature.

  5. Geometric obstruction of black holes

    CERN Document Server

    Punzi, R; Wohlfarth, M N R; Punzi, Raffaele; Schuller, Frederic P.; Wohlfarth, Mattias N. R.

    2006-01-01

    We study the global structure of Lorentzian manifolds with partial sectional curvature bounds. In particular, we prove completeness theorems for homogeneous and isotropic cosmologies as well as static spherically symmetric spacetimes. The latter result is used to rigorously prove the absence of static spherically symmetric black holes in more than three dimensions. The proofs of these new results are preceded by a detailed exposition of the local aspects of sectional curvature bounds for Lorentzian manifolds, which extends and strengthens previous constructions.

  6. A Black Hole Life Preserver

    CERN Document Server

    Gott, J R; Freedman, Deborah L.

    2003-01-01

    Since no one lives forever, all a life preserver can really do is prolong life for longer than would have otherwise been the case. With this rather limited definition in mind we explore in this paper whether in principle you can take a life preserver with you to protect you (for a while at least) against the tidal forces encountered on a trip inside a black hole.

  7. Van der Waals black hole

    Directory of Open Access Journals (Sweden)

    Aruna Rajagopal

    2014-10-01

    Full Text Available In the context of extended phase space, where the negative cosmological constant is treated as a thermodynamic pressure in the first law of black hole thermodynamics, we find an asymptotically AdS metric whose thermodynamics matches exactly that of the Van der Waals fluid. We show that as a solution of Einstein's equations, the corresponding stress energy tensor obeys (at least for certain range of metric parameters all three weak, strong, and dominant energy conditions.

  8. Gayge Fields and Black Holes

    Science.gov (United States)

    Gal'Tsov, D. V.

    1987-10-01

    Exact solutions of the Einstein-Yang-Mills and Einstein-Yang-Mills-Higgs systems of equations are examined, which describe Black Holes, with gluonic and scalar hairs. A simple deduction of these equations, based on the use of the gayge symmetry is given. The transition to a nonsingular gayge for gravitating Wu - Yang monopoles, in which the singularity is headen inside the horizon, is discussed. Bibliography: 11

  9. Black Hole Thermodynamics and Electromagnetism

    CERN Document Server

    Sidharth, B G

    2005-01-01

    We show a strong parallel between the Hawking, Beckenstein black hole Thermodynamics and electromagnetism: When the gravitational coupling constant transform into the electromagnetic coupling constant, the Schwarzchild radius, the Beckenstein temperature, the Beckenstein decay time and the Planck mass transform to respectively the Compton wavelength, the Hagedorn temperature, the Compton time and a typical elementary particle mass. The reasons underlying this parallalism are then discussed in detail.

  10. Black Holes and Random Matrices

    CERN Document Server

    Cotler, Jordan S; Hanada, Masanori; Polchinski, Joseph; Saad, Phil; Shenker, Stephen H; Stanford, Douglas; Streicher, Alexandre; Tezuka, Masaki

    2016-01-01

    We argue that the late time behavior of horizon fluctuations in large anti-de Sitter (AdS) black holes is governed by the random matrix dynamics characteristic of quantum chaotic systems. Our main tool is the Sachdev-Ye-Kitaev (SYK) model, which we use as a simple model of a black hole. We use an analytically continued partition function $|Z(\\beta +it)|^2$ as well as correlation functions as diagnostics. Using numerical techniques we establish random matrix behavior at late times. We determine the early time behavior exactly in a double scaling limit, giving us a plausible estimate for the crossover time to random matrix behavior. We use these ideas to formulate a conjecture about general large AdS black holes, like those dual to 4D super-Yang-Mills theory, giving a provisional estimate of the crossover time. We make some preliminary comments about challenges to understanding the late time dynamics from a bulk point of view.

  11. Black Holes as Effective Geometries

    CERN Document Server

    Balasubramanian, Vijay; El-Showk, Sheer; Messamah, Ilies

    2008-01-01

    Gravitational entropy arises in string theory via coarse graining over an underlying space of microstates. In this review we would like to address the question of how the classical black hole geometry itself arises as an effective or approximate description of a pure state, in a closed string theory, which semiclassical observers are unable to distinguish from the "naive" geometry. In cases with enough supersymmetry it has been possible to explicitly construct these microstates in spacetime, and understand how coarse-graining of non-singular, horizon-free objects can lead to an effective description as an extremal black hole. We discuss how these results arise for examples in Type II string theory on AdS_5 x S^5 and on AdS_3 x S^3 x T^4 that preserve 16 and 8 supercharges respectively. For such a picture of black holes as effective geometries to extend to cases with finite horizon area the scale of quantum effects in gravity would have to extend well beyond the vicinity of the singularities in the effective t...

  12. Hair of astrophysical black holes

    CERN Document Server

    Lyutikov, Maxim

    2012-01-01

    The "no hair" theorem is not applicable to black holes formed from collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively "frozen-in" the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes N_B = e \\Phi_\\infty /(\\pi c \\hbar), where \\Phi_\\infty is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. The black hole's magnetosphere subsequently relaxes to the split monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that...

  13. Soft Hair on Black Holes.

    Science.gov (United States)

    Hawking, Stephen W; Perry, Malcolm J; Strominger, Andrew

    2016-06-10

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.

  14. Fractal black holes and information

    Energy Technology Data Exchange (ETDEWEB)

    El Naschie, M.S. [Department of Physics, University of Alexandria, Alexandria (Egypt); Department of Astrophysics, Cairo University (Egypt); Department of Physics, Mansura University (Egypt)

    2006-07-15

    If nature is fractal as it evidently is, at classical resolution and if it is suspected to also be fractal at the quantum resolution as it is now a days generally believed to be, then we must have over looked at least two points or so in our physical model building of mini black holes. To start with at such ultra high resolution, the mini black hole geometry must be a fractal. Consequently we have zero volume and only a fractal surface area. Second because we cannot take the differential limit for the -bar {sub p}{sup 2} covering the transfinite surface area, there will be many gaps between the (-bar {sub p}){sup 2} tilings. In other words we must introduce transfinite corrections to the final result. Proceeding this way the information entropy unit of a black hole should be a=I=(7+{phi}{sup 3})(10){sup -66}cm{sup 2}=7.23606799(10){sup -66}cm{sup 2}The nearest classical result to the above is that obtained by Gerard 't Hoofta=I=(0.724)(10){sup -65}cm{sup 2}The paper ends with a general discussion of E-infinity theory and its possible relation with 't Hooft's holographic principle and his gluons-quark strings.

  15. Soft Hair on Black Holes

    CERN Document Server

    Hawking, Stephen W; Strominger, Andrew

    2016-01-01

    It has recently been shown that BMS supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft ($i.e.$ zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This paper gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the ho...

  16. Entanglement Entropy of Black Holes

    Directory of Open Access Journals (Sweden)

    Sergey N. Solodukhin

    2011-10-01

    Full Text Available The entanglement entropy is a fundamental quantity, which characterizes the correlations between sub-systems in a larger quantum-mechanical system. For two sub-systems separated by a surface the entanglement entropy is proportional to the area of the surface and depends on the UV cutoff, which regulates the short-distance correlations. The geometrical nature of entanglement-entropy calculation is particularly intriguing when applied to black holes when the entangling surface is the black-hole horizon. I review a variety of aspects of this calculation: the useful mathematical tools such as the geometry of spaces with conical singularities and the heat kernel method, the UV divergences in the entropy and their renormalization, the logarithmic terms in the entanglement entropy in four and six dimensions and their relation to the conformal anomalies. The focus in the review is on the systematic use of the conical singularity method. The relations to other known approaches such as ’t Hooft’s brick-wall model and the Euclidean path integral in the optical metric are discussed in detail. The puzzling behavior of the entanglement entropy due to fields, which non-minimally couple to gravity, is emphasized. The holographic description of the entanglement entropy of the black-hole horizon is illustrated on the two- and four-dimensional examples. Finally, I examine the possibility to interpret the Bekenstein-Hawking entropy entirely as the entanglement entropy.

  17. Entropy of Quantum Black Holes

    Directory of Open Access Journals (Sweden)

    Romesh K. Kaul

    2012-02-01

    Full Text Available In the Loop Quantum Gravity, black holes (or even more general Isolated Horizons are described by a SU(2 Chern-Simons theory. There is an equivalent formulation of the horizon degrees of freedom in terms of a U(1 gauge theory which is just a gauged fixed version of the SU(2 theory. These developments will be surveyed here. Quantum theory based on either formulation can be used to count the horizon micro-states associated with quantum geometry fluctuations and from this the micro-canonical entropy can be obtained. We shall review the computation in SU(2 formulation. Leading term in the entropy is proportional to horizon area with a coefficient depending on the Barbero-Immirzi parameter which is fixed by matching this result with the Bekenstein-Hawking formula. Remarkably there are corrections beyond the area term, the leading one is logarithm of the horizon area with a definite coefficient −3/2, a result which is more than a decade old now. How the same results are obtained in the equivalent U(1 framework will also be indicated. Over years, this entropy formula has also been arrived at from a variety of other perspectives. In particular, entropy of BTZ black holes in three dimensional gravity exhibits the same logarithmic correction. Even in the String Theory, many black hole models are known to possess such properties. This suggests a possible universal nature of this logarithmic correction.

  18. Reed's Conjecture on hole expansions

    CERN Document Server

    Fouquet, Jean-Luc

    2012-01-01

    In 1998, Reed conjectured that for any graph $G$, $\\chi(G) \\leq \\lceil \\frac{\\omega(G) + \\Delta(G)+1}{2}\\rceil$, where $\\chi(G)$, $\\omega(G)$, and $\\Delta(G)$ respectively denote the chromatic number, the clique number and the maximum degree of $G$. In this paper, we study this conjecture for some {\\em expansions} of graphs, that is graphs obtained with the well known operation {\\em composition} of graphs. We prove that Reed's Conjecture holds for expansions of bipartite graphs, for expansions of odd holes where the minimum chromatic number of the components is even, when some component of the expansion has chromatic number 1 or when a component induces a bipartite graph. Moreover, Reed's Conjecture holds if all components have the same chromatic number, if the components have chromatic number at most 4 and when the odd hole has length 5. Finally, when $G$ is an odd hole expansion, we prove $\\chi(G)\\leq\\lceil\\frac{\\omega(G)+\\Delta(G)+1}{2}\\rceil+1$.

  19. Bleed Hole Flow Phenomena Studied

    Science.gov (United States)

    1997-01-01

    Boundary-layer bleed is an invaluable tool for controlling the airflow in supersonic aircraft engine inlets. Incoming air is decelerated to subsonic speeds prior to entering the compressor via a series of oblique shocks. The low momentum flow in the boundary layer interacts with these shocks, growing in thickness and, under some conditions, leading to flow separation. To remedy this, bleed holes are strategically located to remove mass from the boundary layer, reducing its thickness and helping to maintain uniform flow to the compressor. The bleed requirements for any inlet design are unique and must be validated by extensive wind tunnel testing to optimize performance and efficiency. To accelerate this process and reduce cost, researchers at the NASA Lewis Research Center initiated an experimental program to study the flow phenomena associated with bleed holes. Knowledge of these flow properties will be incorporated into computational fluid dynamics (CFD) models that will aid engine inlet designers in optimizing bleed configurations before any hardware is fabricated. This ongoing investigation is currently examining two hole geometries, 90 and 20 (both with 5-mm diameters), and various flow features.

  20. Soft Hair on Black Holes

    Science.gov (United States)

    Hawking, Stephen W.; Perry, Malcolm J.; Strominger, Andrew

    2016-06-01

    It has recently been shown that Bondi-van der Burg-Metzner-Sachs supertranslation symmetries imply an infinite number of conservation laws for all gravitational theories in asymptotically Minkowskian spacetimes. These laws require black holes to carry a large amount of soft (i.e., zero-energy) supertranslation hair. The presence of a Maxwell field similarly implies soft electric hair. This Letter gives an explicit description of soft hair in terms of soft gravitons or photons on the black hole horizon, and shows that complete information about their quantum state is stored on a holographic plate at the future boundary of the horizon. Charge conservation is used to give an infinite number of exact relations between the evaporation products of black holes which have different soft hair but are otherwise identical. It is further argued that soft hair which is spatially localized to much less than a Planck length cannot be excited in a physically realizable process, giving an effective number of soft degrees of freedom proportional to the horizon area in Planck units.