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Sample records for burr hole drainage

  1. Evaluation of awake burr hole drainage for chronic subdural hematoma in geriatric patients: a retrospective analysis of 3 years

    OpenAIRE

    Serdal Albayrak; ibrahim Burak Atci; Necati Ucler; Hakan Yilmaz; Metin Kaplan

    2016-01-01

    Purpose: The goal of this research was to evaluate the effectiveness of burr hole drainage under local anesthesia in geriatric patients with chronic subdural hematoma. Material and Methods: This retrospective study involved 21 geriatric patients with chronic subdural hematoma who applied to the department of neurosurgery in an education and research hospital between 2011 and 2014. Sedoanalgesia was performed on 21 patients, then awake burr hole drainage was performed after scalp and perios...

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

    Directory of Open Access Journals (Sweden)

    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.

  3. 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.

  4. 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 ...... drilled holes was fulfilled as well as high productivity achieved. Such optimized process results in a noticeable production cost reduction....

  5. A prospective randomized study of use of drain versus no drain after burr-hole evacuation of chronic subdural hematoma

    OpenAIRE

    Amit Kumar Singh; Bhaskar Suryanarayanan; Ajay Choudhary; Akhila Prasad; Sachin Singh; Laxmi Narayan Gupta

    2014-01-01

    Objective: Chronic subdural hematoma (CSDH) recurs after surgical evacuation in 5-30% of patients. Inserting subdural drain might reduce the recurrence rate, but is not commonly practiced. There are few prospective studies to evaluate the effect of subdural drains. Materials and Methods: A prospective randomized study to investigate the effect of subdural drains in the on recurrence rates and clinical outcome following burr-hole drainage (BHD) of CSDH was undertaken. During the study period, ...

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Hole quality and burr reduction in drilling aluminium sheets

    DEFF Research Database (Denmark)

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

    2012-01-01

    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...

  8. 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.

  9. Impact of Time Interval between Trauma Onset and Burr Hole Surgery on Recurrence of Late Subacute or Chronic Subdural Hematoma

    Science.gov (United States)

    Kim, Dae-in; Kim, Jae-hoon; Kang, Hee-in; Moon, Byung-gwan; Kim, Joo-seung

    2016-01-01

    Objective Although subdural hematoma (SDH) is commonly treatable by burr hole surgery in the late subacute or chronic stage, there is no clear consensus regarding appropriate management and exact predictive factors for postoperative recurrence also remain unclear. The aim of this study was to evaluate risk factors associated with recurrence of SDH that requires burr hole surgery in the late subacute or chronic stage. We also identified the appropriate timing of surgery for reducing the recurrence. Methods We retrospectively reviewed 274 patients with SDH in the late subacute or chronic stage treated with burr hole surgery in our hospital between January 2007 and December 2014. Excluding patients with acute intracranial complications or unknown time of trauma onset left 216 patients included in the study. Results Of 216 patients with SDH in the late subacute or chronic stage, recurrence was observed in 36 patients (16.7%). The timing of the operation in patients with late subacute stage (15–28 days) resulted in a significant decrease in recurrence (RR, 0.33; 95% CI, 0.17–0.65; p=0.001) compared to chronic stage (>28 days). Otherwise, no significant risk factors were associated with recurrences including comorbidities and surgical details. Conclusion The results indicated that time from trauma onset to burr hole surgery may be important for decreasing the risk of recurrence. Therefore, unless patients can be treated conservatively without surgery, prompt surgical management is recommended in patients diagnosed as having late subacute or chronic subdural hematoma treatable by burr hole surgery, even when neurological deficits are unclear.

  10. 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

  11. Effects of drilling variables on burr properties

    Energy Technology Data Exchange (ETDEWEB)

    Gillespie, L.K.

    1976-09-01

    An investigation utilizing 303Se stainless steel, 17-4PH stainless steel, 1018 steel, and 6061-T6 aluminum was conducted to determine the influence of drilling variables in controlling burr size to minimize burr-removal cost and improve the quality and reliability of parts for small precision mechanisms. Burr thickness can be minimized by reducing feedrate and cutting velocity, and by using drills having high helix angles. High helix angles reduce burr thickness, length, and radius, while most other variables reduce only one of these properties. Radial-lip drills minimize burrs from 303Se stainless steel when large numbers of holes are drilled; this material stretches 10 percent before drill-breakthrough. Entrance burrs can be minimized by the use of subland drills at a greatly increased tool cost. Backup-rods used in cross-drilled holes may be difficult to remove and may scratch the hole walls.

  12. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  14. Evaluation of awake burr hole drainage for chronic subdural hematoma in geriatric patients: a retrospective analysis of 3 years

    Directory of Open Access Journals (Sweden)

    Serdal Albayrak

    2016-03-01

    Conclusion: Surgical interventions under local anesthesia in geriatric patients with chronic subdural hematoma can provide short operation time, early mobilization, early oral intake, avoidance of possible general anesthesia complications. Herewith, this intervention decrease mortality and morbidity in this age group. [Cukurova Med J 2016; 41(1.000: 69-73

  15. Observation of Drilling Burr and Finding out the Condition for Minimum Burr Formation

    Directory of Open Access Journals (Sweden)

    Nripen Mondal

    2014-01-01

    Full Text Available Suppression or elimination of burr formation at the exit edge of the workpiece during drilling is essential to make quality products. In this work, low alloy steel specimens have been drilled to observe burr height under different machining conditions. Taper shank, uncoated 14 mm diameter HSS twist drills are used in these experiments. Dry environment is maintained in experiment set I. Water is applied as cutting fluid in experiment set II. In the next four sets of experiments, the effect of providing back-up support material and exit edge bevel is observed on formation of burr at the exit edge of specimens under dry and wet conditions. It is revealed that an exit edge bevel of 31 degrees with water as the cutting fluid gives negligible burr at the exit edge of the drilled hole at certain machining conditions. Use of a back-up support can also reduce drill burr to a large extent. In this paper, artificial neural networks (ANN are developed for modeling experimental results, and modeled values show close matching with the experimental results with small deviations.

  16. "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

  17. 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.

  18. Chronic subdural hematoma: a comparison of two drainage methods

    Directory of Open Access Journals (Sweden)

    Lotfinia

    2008-08-01

    Full Text Available "nBackground: Chronic Subdural Hematoma (CSDH is one of the most common challenges of neurosurgeons. Most predominant among the elderly, the incidence increases incrementally with age and might lead to permanent severe complications. The aim of this study is to outline the symptoms and signs and to compare the outcomes and complications among two groups of patients who underwent two different surgical procedures."n"nMethods: In a cross-sectional and descriptive-analytical study performed on 125 patients with CSDH from 2000 to 2005. Computed tomography scan was used for diagnostic imaging in all cases and magnetic resonance imaging was also obtained for six patients. In one center, group 1, which included 82 patients, underwent surgery with a single burr hole and closed drainage, and, at another center, group 2, which included 43 patients, was treated with a method using two burr holes and close drainage."n"nResults: Of the 125 patients, 102 were male and 23 were female. The mean age of patients was 65.79±16.41 years. The most common symptoms were weakness in extremities (78.4%, headache (72.8% and decreased level of consciousness (24%, respectively. At presentation, 88 (70.4% of the patients had several symptoms and 37 (29.6% had only one symptom. A history of mild head trauma, such as falling, was observed in 83 (68% of the patients. The interval between head trauma and the onset of symptoms ranged from 10 to 120 days (mean: 46 days. Hematoma recurred in five cases from group 1, whereas two cases from group 2 had recurrence of hematoma. Postoperative epidural hematoma developed in one case from group 2 and tension pneumocephalus also occurred in one group 2 patients."n"nConclusion: As a treatment for CSDH, the single burr hole method was significantly better than the two burr hole method.

  19. 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...

  20. 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.

  1. 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.

  2. Copula method for specific Burr distribution

    Science.gov (United States)

    Ismail, Nor Hidayah Binti; Khalid, Zarina Binti Mohd

    2015-02-01

    Copula method is discovered to become a useful method to joint two distributions and is known as dependence functions. It is a multivariate distribution functions whose one-dimensional margins are uniform on the interval (0, 1). The used of copula has expanded in many fields of study. Copula has many classes and families. However, in this research, copula methods which are Ali-Mikhail-Haq (AMH), Clayton and Gumbel are used on uncensored data to join specific Burr Type III and XII distributions using the theorem and algorithm of construction the copula. The result showed that AMH, Clayton and Gumbel copula fitted well with Burr distribution since the values of copula lie on the interval (0, 1).

  3. 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.

  4. Research on Modified Hole Pattern for Pressure-relief Gas Drainage from Upper Adjacent Seam%上邻近层卸压抽放钻孔布孔方式改进研究

    Institute of Scientific and Technical Information of China (English)

    孙国文

    2013-01-01

      针对松藻煤矿保护层工作面回风巷钻场卸压瓦斯抽放钻孔布置不能满足瓦斯抽放需要的问题,对钻场卸压瓦斯抽放钻孔布孔方式进行改进,由双向扇形布孔改为沿工作面切割方向单向前倾式布孔。布孔方式改进后提高了钻场瓦斯抽放量,减少了工作面瓦斯超限现象,改进的布孔方式具有较好的实用性。%To counter the problem that the pattern of gas-relieving drainage holes can't meet the needs of gas drainage in air-return way in the working face of the protective seam in Songzao Mine,improvement was carried out for the pattern of the gas-relieving drainage holes at the drilling site,the two-way fan-shaped hole pattern was changed into one-way forward-inclined hole pattern along the cutting direction of the face. The improvement of the gas drainage hole pattern raised the gas drainage volume at the drilling site and reduced the gas overrun phenomenon,so it has good practicability.

  5. WATER DRAINAGE MODEL

    Energy Technology Data Exchange (ETDEWEB)

    J.B. Case

    2000-05-30

    The drainage of water from the emplacement drift is essential for the performance of the EBS. The unsaturated flow properties of the surrounding rock matrix and fractures determine how well the water will be naturally drained. To enhance natural drainage, it may be necessary to introduce engineered drainage features (e.g. drilled holes in the drifts), that will ensure communication of the flow into the fracture system. The purpose of the Water Drainage Model is to quantify and evaluate the capability of the drift to remove water naturally, using the selected conceptual repository design as a basis (CRWMS M&O, 1999d). The analysis will provide input to the Water Distribution and Removal Model of the EBS. The model is intended to be used to provide postclosure analysis of temperatures and drainage from the EBS. It has been determined that drainage from the EBS is a factor important to the postclosure safety case.

  6. 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.

  7. 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.

  8. Modifikasi Alat Penggiling Biji Kopi Tipe Flat Burr Mill

    OpenAIRE

    Simanjuntak, Arta Naomi Cristiana

    2015-01-01

    Milling is done to reduce size or to powder food material into a certain level of refinement to be more easily processed into other products. The aims of the was to modificate, design, build and test coffee bean grinder flat burr type mill on robusta coffee. Observed parameters were the effective capacity of the equipment, the percentage of losses materials, and economic analysis. The results showed that the effective capacity of the equipment was 35,66 kg/hour for robusta coffee and 33,84...

  9. 井下瓦斯抽采钻孔机械造穴技术研究%Study of Mechanical Cavity-forming Technology for Underground Gas Drainage Hole Drilling

    Institute of Scientific and Technical Information of China (English)

    赵继展

    2015-01-01

    为了解决低渗透性煤层瓦斯抽采困难的问题,通过理论分析和数值模拟研究了提高钻孔瓦斯抽采效率的主要途径,借鉴煤层气洞穴完井工艺技术,研制了以钻机给进和旋转为动力、适用于井下瓦斯抽采钻孔的开合机械臂式造穴工具,形成了可在井下煤层瓦斯抽采钻孔内定点位置实现Φ600 mm洞穴的工艺技术. 在芦岭煤矿的2组造穴钻孔工程试验表明,机械造穴技术能够明显提高钻孔瓦斯抽采效果,与同一地点的常规瓦斯抽采钻孔相比,造穴钻孔单孔瓦斯抽采浓度提高了2 . 31~4 . 00倍,纯瓦斯流量提高了2 . 63~5 . 11倍.%In order to solve the problem of difficult gas drainage from the coal seam with low permeability, study was carried out on the main ways for improving gas drainage efficiency by theoretical analysis and numerical simulation,coal-bed methane well completion technology was used for reference, a cavity-forming tool with a retractable arm was developed, which took the drill feed and rotation as the power and was suitable to drill gas drainage holes, with this cavity-forming tool, Φ600 mm cavity-forming technology can be achieved at a fixed position in underground gas drainage holes. The cavity-forming drilling test in Luling Coal Mine showed that the mechanical cavity-forming technology for coal gas drainage drilling can significantly improve the efficiency of gas drainage, and compared with the conventional gas drainage drilling, the gas concentration of a single hole with the cavity-forming drilling technology increased by 2. 31 to 4. 00 times and the pure gas flow increased by 2. 63 ~ 5. 11 times.

  10. Influences on Burr Size During Face-Milling of Aluminum Alloys and Cast Iron

    OpenAIRE

    Shefelbine, Wendy; Dornfeld, David

    2004-01-01

    The Exit Order Sequence (EOS) theory discussed by previous LMA students predicts the size of burrs formed during face milling. Other influences are tool geometry, coolant use, and material properties in aluminum silicon alloys and cast iron. Used, worn tools also increase the size of the burr. The effect of speed and feed are also discussed, particularly with regards to cast iron.

  11. 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.

  12. [Phytopharmacological review of bathurst burr (Xanthium spinosum L.)].

    Science.gov (United States)

    Domokos Erzsébet; Kursinszki, Lászlo; Kelemen, Hajnal; Varga, Erzétbet

    2016-01-01

    Bathurst burr (Xanthium spinosum L.) is an invasive species that is also known as a medicinal plant. Our goal is to make known the plant and its therapeutic effects in larger scale. The plant has been used in the Romanian folk medicine for urinary problems and various prostate diseases. The most important substances in Xanthii spinosi herba are: flavones and their derivates (quercetin, pendulin, iocein, centaurin and patuletin), polyphenols (caffeic- and chlorogenic acid and their derivates), sesquiterpene lactones (xanthinin, xanthatin-xanthanol-xanthumin derivates), diterpenes (atractyloside and derivates) and phytosterols (sitosterol, stigmasterol). The beneficial effect of the herb was proved in the 80's by Petcu and his collaborators. The plants infusion and tincture had positive effects on induced benign prostate hyperplasia in rats. The antibacterial and antifungal properties of the plant are attributed to the sesquiterpene lactone, xanthatin. Our preliminary experiments showed the presence of the xanthatin in the toluol, chloroform, methanol and ethanol extracts. PMID:27295875

  13. 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.

  14. 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.

  15. 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.

  16. 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)

    HAN XueSong; HU YuanZhong

    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 manufacturing technology, the depth of cut falls into the range of nanometer or subnanometer, there may be some different disciplines dominating the burrs generation process. Molecular dynamics (MD) method, which is different from continuous mechanics, plays an important role in describing microscopic world. Take the example of single crystal copper, this paper carries out MD analysis micro-mechanism of burrs generation process. The results show that the burrs geometry depends 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.

  17. Foam drainage

    Energy Technology Data Exchange (ETDEWEB)

    Kraynik, A.M.

    1983-11-01

    Transient drainage from a column of persistent foam has been analyzed theoretically. Gravity-driven flow was assumed to occur through an interconnected network of Plateau borders that define the edges of foam cells taken to be regular pentagonal dodecahedrons. A small liquid volume fraction and monodisperse cell size distribution were assumed. In the basic model, it is assumed that all liquid is contained in Plateau borders that are bounded by rigid gas-liquid interfaces. The predicted half life, the time required for one half of the liquid to drain from the foam, is inversely proportional to the square of the cell diameter, illustrating the importance of foam structure in drainage. Liquid hold up in the films separating adjacent cells, nonuniform initial liquid volume fraction distribution and interfacial mobility are explored. Border suction due to reduced pressure in the Plateau borders provides a mechanism for film drainage. Simultaneous film drainage and flow through the Plateau borders are analyzed. Sufficient conditions for neglecting film drainage kinetics are obtained. The results indicate that improved foam stability is related to small cells, liquid hold up in the films and slow film drainage kinetics.

  18. 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.

  19. Modified Maximum Likelihood Estimation from Censored Samples in Burr Type X Distribution

    Directory of Open Access Journals (Sweden)

    R.R.L. Kantam

    2015-12-01

    Full Text Available The two parameter Burr type X distribution is considered and its scale parameter is estimated from a censored sample using the classical maximum likelihood method. The estimating equations are modified to get simpler and efficient estimators. Two methods of modification are suggested. The small sample efficiencies are presented.

  20. 21 CFR 882.4305 - Powered compound cranial drills, burrs, trephines, and their accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered compound cranial drills, burrs, trephines, and their accessories. 882.4305 Section 882.4305 Food and Drugs FOOD AND DRUG ADMINISTRATION... tip of the instrument after penetrating the skull to prevent plunging of the tip into the brain....

  1. 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...

  2. On Maximum Likelihood Estimation for Left Censored Burr Type III Distribution

    Directory of Open Access Journals (Sweden)

    Navid Feroze

    2015-12-01

    Full Text Available Burr type III is an important distribution used to model the failure time data. The paper addresses the problem of estimation of parameters of the Burr type III distribution based on maximum likelihood estimation (MLE when the samples are left censored. As the closed form expression for the MLEs of the parameters cannot be derived, the approximate solutions have been obtained through iterative procedures. An extensive simulation study has been carried out to investigate the performance of the estimators with respect to sample size, censoring rate and true parametric values. A real life example has also been presented. The study revealed that the proposed estimators are consistent and capable of providing efficient results under small to moderate samples.

  3. 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.

  4. 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.

  5. 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.

  6. Mine drainage treatment

    OpenAIRE

    Golomeova, Mirjana; Zendelska, Afrodita; Krstev, Boris; Golomeov, Blagoj; Krstev, Aleksandar

    2012-01-01

    Water flowing from underground and surface mines and contains high concentrations of dissolved metals is called mine drainage. Mine drainage can be categorized into several basic types by their alkalinity or acidity. Sulfide rich and carbonate poor materials are expected to produce acidic drainage, and alkaline rich materials, even with significant sulfide concentrations, often produce net alkaline water. Mine drainages are dangerous because pollutants may decompose in the environment. In...

  7. Drainage of radioactive areas

    International Nuclear Information System (INIS)

    This Code of Practice covers all the drainage systems which may occur in the radioactive classified area of an establishment, namely surface water, foul, process and radioactive drainage. It also deals with final discharge lines. The Code of Practice concentrates on those aspects of drainage which require particular attention because the systems are in or from radioactive areas and typical illustrations are given in appendices. The Code makes references to sources of information on conventional aspects of drainage design. (author)

  8. Transient drainage summary report

    International Nuclear Information System (INIS)

    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

  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. New functionally dioecious bush tomato from northwestern Australia, Solanum ossicruentum, may utilize "trample burr" dispersal.

    Science.gov (United States)

    Martine, Christopher T; Cantley, Jason T; Frawley, Emma S; Butler, Alice R; Jordon-Thaden, Ingrid E

    2016-01-01

    A new Australian species of functionally dioecious bush tomato of Solanum subgenus Leptostemonum is described. Solanum ossicruentum Martine & J.Cantley, sp. nov., is thought to be allied with members of the problematic "Dioicum Complex" lineage, but differs in its short silvery indumentum, long calyx lobes, larger stature, and an unusual fruit morphology that may represent "trample burr" seed dispersal. The species occurs in a range extending from the eastern Kimberley in Western Australia to far northwestern Northern Territory and has been recognized for decades as a variant of Solanum dioicum W.Fitzg. Specimens of this species were previously referred to by D.E. Symon and others as Solanum dioicum 'Tanami.' Ex situ crossing studies and SEM images of inaperturate pollen grains produced in morphologically hermaphrodite flowers indicate that this taxon is functionally dioecious. The scientific name was chosen with the help of 150 seventh grade life science students from Pennsylvania, USA. PMID:27489475

  11. The Effect of Kinematical Parameters and Tool Geometry on Burr Height in Face Milling of Al-Si Alloys

    OpenAIRE

    Avila, Miguel C.; Dornfeld, David A

    2003-01-01

    High speed face milling test were performed on two aluminum silicon alloys currently used in automotive engine production to study the effect of cutting parameters and tool geometry in edge quality. Axial Rake and Radial Rake angles were varied to assess their effect in burr formation, as well as cutting speed, feedrate and depth of cut. Significant improvements in edge quality were obtained by optimizing these geometrical and kinematical parameters.

  12. 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...

  13. Preoperative biliary drainage.

    Science.gov (United States)

    Saxena, Payal; Kumbhari, Vivek; Zein, Mohamad E L; Khashab, Mouen A

    2015-01-01

    The role of preoperative biliary drainage (PBD) in patients with distal or proximal biliary obstruction secondary to resectable tumors has been a matter for debate. A review of the literature using Medline, Embase and Cochrane databases was undertaken for studies evaluating routes of drainage (endoscopic or percutaneous) and stent types (plastic or metal) in patients with resectable disease. Preoperative biliary drainage is indicated for relief of symptomatic jaundice, cholangitis, patients undergoing neoadjuvant therapy or those patients where surgery may be delayed. Endoscopic methods are preferred over percutaneous methods because of lower complication rates. In patients with proximal biliary obstruction, PBD should be guided by imaging studies to aid in selective biliary cannulation for unilateral drainage in order to reduce the risk of cholangitis in undrained liver segments. PMID:25293587

  14. DRAINAGE NETWORKS AFTER WILDFIRE

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Predicting runoff and erosion from watersheds burned by wildfires requires an understanding of the three-dimensional structure of both hillslope and channel drainage networks. We investigate the small- and large-scale structures of drainage networks using field studies and computer analysis of 30-m digital elevation model. Topologic variables were derived from a composite 30-m DEM, which included 14 order 6 watersheds within the Pikes Peak batholith. Both topologic and hydraulic variables were measured in the field in two smaller burned watersheds (3.7 and 7.0 hectares) located within one of the order 6 watersheds burned by the 1996 Buffalo Creek Fire in Central Colorado. Horton ratios of topologic variables (stream number, drainage area, stream length, and stream slope) for small-scale and large-scale watersheds are shown to scale geometrically with stream order (i.e., to be scale invariant). However, the ratios derived for the large-scale drainage networks could not be used to predict the rill and gully drainage network structure. Hydraulic variables (width, depth, cross-sectional area, and bed roughness) for small-scale drainage networks were found to be scale invariant across 3 to 4 stream orders. The relation between hydraulic radius and cross-sectional area is similar for rills and gullies, suggesting that their geometry can be treated similarly in hydraulic modeling. Additionally, the rills and gullies have relatively small width-to-depth ratios, implying sidewall friction may be important to the erosion and evolutionary process relative to main stem channels.

  15. Drainage networks after wildfire

    Science.gov (United States)

    Kinner, D.A.; Moody, J.A.

    2005-01-01

    Predicting runoff and erosion from watersheds burned by wildfires requires an understanding of the three-dimensional structure of both hillslope and channel drainage networks. We investigate the small-and large-scale structures of drainage networks using field studies and computer analysis of 30-m digital elevation model. Topologic variables were derived from a composite 30-m DEM, which included 14 order 6 watersheds within the Pikes Peak batholith. Both topologic and hydraulic variables were measured in the field in two smaller burned watersheds (3.7 and 7.0 hectares) located within one of the order 6 watersheds burned by the 1996 Buffalo Creek Fire in Central Colorado. Horton ratios of topologic variables (stream number, drainage area, stream length, and stream slope) for small-scale and large-scale watersheds are shown to scale geometrically with stream order (i.e., to be scale invariant). However, the ratios derived for the large-scale drainage networks could not be used to predict the rill and gully drainage network structure. Hydraulic variables (width, depth, cross-sectional area, and bed roughness) for small-scale drainage networks were found to be scale invariant across 3 to 4 stream orders. The relation between hydraulic radius and cross-sectional area is similar for rills and gullies, suggesting that their geometry can be treated similarly in hydraulic modeling. Additionally, the rills and gullies have relatively small width-to-depth ratios, implying sidewall friction may be important to the erosion and evolutionary process relative to main stem channels.

  16. Wound Drainage Culture (For Parents)

    Science.gov (United States)

    ... Melon Smoothie Pregnant? Your Baby's Growth Wound Drainage Culture KidsHealth > For Parents > Wound Drainage Culture Print A A A Text Size What's in ... de heridas What It Is A wound drainage culture is a test to detect germs such as ...

  17. A study on the analysis method of shape quality and the micro burr removal on a micro pyramid pattern using the micro MR fluid jet polishing system

    Science.gov (United States)

    Lee, J. W.; Ha, S. J.; Hong, K. P.; Cho, Y. K.; Kim, K. B.; Kim, B. C.; Cho, M. W.

    2016-04-01

    Recently, micro square pyramid patterns which can be obtained by a light diffusion effect have been widely studied and examined. However, micro pyramid patterns are difficult to fabricate, because of a deburring problem. Therefore, a micro machining technology for the fabrication of micro pyramid patterns has emerged as an essential element. Burr can almost be generated on the edge of the micro pattern when the micro square pyramid pattern is manufactured by a mechanical cutting process. The micro pyramid pattern shape is difficult to maintain as an original form when the burrs are removed. So various methods have been used in an attempt to remove the burrs. A micro magnetorheological (MR) fluid jet polishing process is one of various methods to remove burrs. The process can control shear force for material removing it by a controlled viscosity of the MR fluid due to magnetic-field adjusting. In this paper, magnetic analysis and the deburring process were carried out to fabricate a micro square pyramid pattern on brass (non-magnetic material) and nickel (ferromagnetic material) using a micro MR fluid jet polishing system. Finally, the deburring characteristics and the shape analysis of micro pyramid patterns were investigated by using a micro MR fluid jet polishing system.

  18. Commercial-scale evaluation of two agricultural waste products, cotton burr/stem and module wraps in thermoplastic composites and comparison with laboratory-scale results

    Science.gov (United States)

    Laboratory-scale research had shown the potential of using cotton burr/stem (CBS) as a fiber filler in thermoplastic composites. This study evaluates the potential of using waste materials from cotton harvesting/ginning operations, CBS, and cotton module wraps (CMW) as a filler and substrate in ther...

  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. 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.

  1. 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

  2. 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. ...

  3. Non-predatory ingestive behaviors of the praying mantids Tenodera aridifolia sinensis (Sauss.) and Sphodromantis lineola (Burr.).

    Science.gov (United States)

    Prete, F R; Lum, H; Grossman, S P

    1992-01-01

    Praying mantids are thought to be so strictly predacious that, historically, carnivorousness has been used as a defining characteristics of the taxon Mantodea, and no data exist on other ingestive behaviors. We observed food- and water-deprived male and female Tenodera aridifolia sinensis (Sauss.) and Sphodromantis lineola (Burr.) in various situations and found that their ingestive behaviors are more variable than generally recognized. Both species regularly drink water in response to deprivation, the amount imbibed being correlated with the total (but not daily) percent of initial body weight lost. When presented with stimuli consisting of plastic beads of different reflective quality (shiny clear, opaque frosted, or matte black), lighted by a single direct light source, the shiny stimuli consistently elicited the most drinking-like behavior by the mantids. The preference was consistent, whether stimuli were presented together or singly. This suggests that visual cues can be used to identify water and are alone capable of maintaining drinking-like behavior. When S. lineola were presented with various stimuli, including diced apple and diced banana, in a five-way or a three-way choice test, mantids that chose a stimulus within the allotted time consistently ate the diced banana. When presented one of two stimuli differing only in odor (30 x 20 x 15 mm cloth bags filled with either plastic beads or banana), S. lineola did not attempt to eat the former, but 50% attempted to eat the bag of banana. Eating bouts were always preceded by antennae drumming in the direction of, or over the stimulus.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1555110

  4. Stimulus speed and order of presentation effect the visually released predatory behaviors of the praying mantis Sphodromantis lineola (Burr.).

    Science.gov (United States)

    Prete, F R; Placek, P J; Wilson, M A; Mahaffey, R J; Nemcek, R R

    1993-01-01

    To assess the role of stimulus speed and order on the predatory behaviors of the praying mantis Sphodromantis lineola (Burr.), tethered adult females were presented with various flat black stimuli (lures) by means of a variable speed mechanical arm. Lure speed had a dramatic effect on mantis behavior: mantises emitted significantly more strikes to a 6 x 6 mm square and to 'worm' lures (i.e. length > width = 6 mm) moving at 34.3 cm/sec than they did to 'antiworm' lures (i.e. width > length = 6 mm), or to slower moving lures. These effects were consistent over lure directions (0-75 degrees relative to the mantis' long axis), and background patterns. On the other hand, mantises emitted significantly more approaching behavior to lures moving at 12 cm/sec than to lures moving at 36 cm/sec. This suggests that S. lineola extract distance information from retinal image velocity, as do other insects. Stimulus order also effected mantis predatory behavior: for instance, mantises were more likely to track a lure without striking at it on the first trial than on subsequent trials. However, after the first trial, they were also more likely to freeze (become immobile) when a lure was presented. Mantises were also less likely to strike at a preferred lure if it was preceded by one or two non-preferred lures. In a final experiment, intact, freely moving mantises were placed in an arena, presented with adult crickets, and video taped. The behaviors of the freely moving mantises were congruent with those of the tethered mantises in the previous experiments. This series of experiments demonstrates that the information processing capabilities of S. lineola are more complex than generally depicted, however, they can be explained by assuming a neural organization similar to that of other insects such as flies (Diptera) and dragonflies (Odonata). PMID:8275297

  5. 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.

  6. 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.

  7. Inner Burr Removing Device of Small Diameter HFW Pipe and Its Troubleshooting%小直径HFW焊管内毛刺清除装置及故障处理

    Institute of Scientific and Technical Information of China (English)

    魏雪冬; 王润成; 王欣悦

    2015-01-01

    简述了内毛刺清除刀杆优缺点,介绍了小直径HFW焊管内毛刺清除刀杆装置的构成及作用。重点分析了小直径HFW焊管生产过程中装置使用及内毛刺清除经常会发生的问题,例如焊接速度慢、焊缝集焊瘤、崩刀、内毛刺残余高度超标、内毛刺刮削呈鱼鳞形状或螺旋状、内毛刺刮偏等常见问题,并根据实际情况对原有设备进行了改进,并提出一些解决措施,以便于国内小直径HFW焊管厂家在实际生产过程中做参考。%The advantages and disadvantages of the inner burr removing cutter arbor for small diameter HFW pipe were described briefly, and the equipment configuration and function were introduced. It focused on the analysis of some problems often encountered in the use of online production device and small diameter HFW pipe inner burr removing process, such as slow welding speed, weld flash, tipping, the burr height exceeding the standard residual inside burr, inner burr scraping in fish scale shape or spiral shape, inner burr scraping partial. According to the actual condition, some feasibility measures were put forward in order to make reference to domestic small diameter HFW pipe manufacturers in the actual production process.

  8. Gravitational drainage of foam films.

    Science.gov (United States)

    Sett, S; Sinha-Ray, S; Yarin, A L

    2013-04-23

    Gravitational drainage from thick plane vertical soap films and hemispherical bubbles is studied experimentally and theoretically. The experiments involve microinterferometry kindred to the one used in the experiments in the Scheludko cell. The following surfactants were used in the experiments: cationic dodecyltrimethylammonium bromide (DTAB), anionic sodium dodecyl sulfate (SDS), anionic Pantene shampoo which primarily contains sodium lauryl sulfate, nonionic tetraethylene glycol monooctyl ether (C8E4), and nonionic Pluronic (P-123) surfactants at different concentrations. The theoretical results explain the drainage mechanism and are used to develop a new method of measurement of the surface elasticity and to test it on the above-mentioned surfactants. PMID:23557027

  9. Laparoscopic Drainage of Pancreatic Pseudocysts

    Directory of Open Access Journals (Sweden)

    Filip Eugen Târcoveanu

    2015-09-01

    Full Text Available Pancreatic pseudocyst is a complication of acute or chronic pancreatitis. The invasive treatment (surgical or endoscopic is recommended if the pseudocyst persisted for more than 6 weeks after the diagnosis and if the size is larger than 6 cm and is symptomatic. The laparoscopic techniques have been developed to provide the patient with the benefits of a minimal access alternative. The aim of this article is to analyze the postoperative results of the pancreatic pseudocyst laparoscopic surgery. We have accomplished a restrospective study using clinical and para-clinical test results and postoperative results from the patients who have been treated with laparoscopic drainage. We reported a case of a large symptomatic pseudocyst after an attack of gallstone pancreatitis. Laparoscopic cholecystectomy and extern drainage have been performed at the same time with good postoperative results. Starting with year 2000 until year 2015, 85 patients, diagnosed with pancreatic pseudocyst, have been treated in the First Surgical Clinic, University Hospital Saint Spiridon Iasi. From which only 8 have been treated with laparoscopic drainage, encountering no mortality and morbidity. Postoperative hospital stay was 9,41 days. The postoperative drainage duration was between 5 and 21 days with a mean of 7 days. Late postoperative results were good in 6 patients and mediocre in the 2 patients. Conclusion: The laparoscopic technique has all the benefits of the minimal invasive approach. Better postoperative results were seen in cysto-digestive anastomosis using a Endo GIA stapler.

  10. Definition of the drainage filter problem

    NARCIS (Netherlands)

    Zaslavsky, D.

    1977-01-01

    It is common to consider the following: I. Retention of soil particles that may enter the drainage pipe and cause its clogging. For some sensitive structures it is important to prevent settlements due to soil transportation by drainage water.

  11. 24 CFR 3285.604 - Drainage system.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Drainage system. 3285.604 Section... § 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...

  12. Drainage water management for water quality protection

    Science.gov (United States)

    Land drainage has been central to the development of North America since colonial times. Increasingly, agricultural drainage is being targeted as a conduit for pollution, particularly nutrient pollution. The export of agricultural drainage water and associated pollutants to surface water can be mana...

  13. Rotational atherectomy using small burr combined with drug-eluting stent implantation for the treatment of heavily calcified coronary lesions: analysis of clinical outcomes

    International Nuclear Information System (INIS)

    Objective: To investigate the safety and efficacy of rotational atherectomy with small burr together with subsequent drug-eluting stent implantation in treating patients with heavily calcified coronary lesions. Methods: During the period from January 2009 to April 2013 a total of 12 patients with heavily calcified coronary lesions were admitted to authors' hospital. The diagnosis was confirmed by angiography in all patients. Rotational atherectomy with small bun combined with subsequent drug-eluting stent implantation were carried out. The clinical data, including angiography success rate, procedure success rate, complications and postoperative main adverse cardiovascular events such as death, myocardial infarction and target lesion revascularization, etc. were retrospectively analyzed. Results: A total of sixteen heavily calcified lesions of Type C in 12 patients were successfully treated with rotational atherectomy and drug-eluting stent placement. After rotational atherectomy the stenosis degree of the coronary artery decreased from preoperative (82.7±7.6)% to postoperative (35.2±10.3)%, the difference between the two was statistically significant (P<0.05), and a total of 22 drug-eluting stents were successfully implanted. The angiography success rate was 100%. The average burr-to-artery ratio used in the procedure was (0.50±0.02), the bun with the diameter ≤1.50 mm was employed in treating 93.7% of lesions (15/16). The success rate of the procedure was 91.7% (11/12). During the procedure stasis of blood flow was observed in one patient, and the patient developed perioperative myocardial infarction. No acute vascular occlusion, coronary perforation, dissection or death occurred, and no patient needed to receive emergency coronary artery bypass grafting. All the patients were followed up for (7.1±2.5) months, and no recurrence of angina pectoris or major cardiovascular event was observed. Conclusion: For the treatment of heavily calcified coronary

  14. 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.

  15. 'Subarachnoid cyst' after evacuation of chronic subdural hematoma: Case report of an unusual postoperative morbidity.

    Science.gov (United States)

    Sharon, Low Y Y; Wai Hoe, N G

    2016-01-01

    Burr-hole drainage of chronic subdural hematomas are routine operative procedures done by neurosurgical residents. Common postoperative complications include acute epidural and/or subdural bleeding, tension pneumocephalus, intracranial hematomas and ischemic cerebral infarction. We report an interesting post-operative complication of a 'subarachnoid cyst' after burr-hole evacuation of a chronic subdural hematoma. The authors hypothesize that the 'cyst' is likely secondary to the splitting of the adjacent neomembrane within its arachnoid-brain interface by iatrogenic irrigation of the subdural space. Over time, this 'cyst' develops into an area of gliosis which eventually causes long-term scar epilepsy in the patient. As far as we are aware, this is the first complication of such a 'subarachnoid cyst' post burr-hole drainage reported in the literature. PMID:27366276

  16. Drainage Areas of Selected Streams in Virginia

    Science.gov (United States)

    Hayes, Donald C.; Wiegand, Ute

    2006-01-01

    Drainage areas were determined for more than 1,600 basins in the three major river basins of Virginia -- the North Atlantic Slope, South Atlantic Slope, and Ohio River Basins. Drainage areas range from 0.004 square mile to 7,866 square miles. A geographic information system was used to digitize and store data associated with the drainage basins. Drainage divides were digitized from digital U.S. Geological Survey 7.5-minute, 1:24,000-scale, topographic quadrangles using procedures recommended by the Subcommittee on Hydrology, Federal Interagency River Basin Committee. Digital drainage basins were quality assured, polygons of the closed drainage basins were generated, and drainage areas were computed.

  17. 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.

  18. 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.”

  19. 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.

  20. ndophthalmitis Following Glaucoma Drainage Implant Surgery

    OpenAIRE

    Tolga Kocatürk; Erol Erkan; Harun Çakmak

    2014-01-01

    Glaucoma surgery is performed widely in our country and all around the world to lower the intraocular pressure in refractory glaucoma. Glaucoma drainage implant surgery has a special and important place among glaucoma surgeries. Among various complications, endophthalmitis is a rare but the most devastating complication after glaucoma drainage implantation. In this review, the clinical characteristics and treatment options of endophthalmitis after glaucoma drainage implant surgery ar...

  1. ndophthalmitis Following Glaucoma Drainage Implant Surgery

    Directory of Open Access Journals (Sweden)

    Tolga Kocatürk

    2014-03-01

    Full Text Available Glaucoma surgery is performed widely in our country and all around the world to lower the intraocular pressure in refractory glaucoma. Glaucoma drainage implant surgery has a special and important place among glaucoma surgeries. Among various complications, endophthalmitis is a rare but the most devastating complication after glaucoma drainage implantation. In this review, the clinical characteristics and treatment options of endophthalmitis after glaucoma drainage implant surgery are discussed according to recent literature. (Turk J Ophthalmol 2014; 44: 138-43

  2. Drainage in a rising foam.

    Science.gov (United States)

    Yazhgur, Pavel; Rio, Emmanuelle; Rouyer, Florence; Pigeonneau, Franck; Salonen, Anniina

    2016-01-21

    Rising foams created by continuously blowing gas into a surfactant solution are widely used in many technical processes, such as flotation. The prediction of the liquid fraction profile in such flowing foams is of particular importance since this parameter controls the stability and the rheology of the final product. Using drift flux analysis and recently developed semi-empirical expressions for foam permeability and osmotic pressure, we build a model predicting the liquid fraction profile as a function of height. The theoretical profiles are very different if the interfaces are considered as mobile or rigid, but all of our experimental profiles are described by the model with mobile interfaces. Even the systems with dodecanol are well known to behave as rigid in forced drainage experiments. This is because in rising foams the liquid fraction profile is fixed by the flux at the bottom of the foam. Here the foam is wet with higher permeability and the interfaces are not in equilibrium. These results demonstrate once again that it is not only the surfactant system that controls the mobility of the interface, but also the hydrodynamic problem under consideration. For example liquid flow through the foam during generation or in forced drainage is intrinsically different. PMID:26554500

  3. Acid mine drainage research in Canada

    International Nuclear Information System (INIS)

    Acidic drainage resulting from base metal, precious metal, and uranium mining is the largest single environmental problems facing the Canadian mining industry today. Technologies to prevent acidic drainage from occurring in waste rock piles and tailings sites, and on the walls of open pits and underground mines, need to be developed and demonstrated. There are two grounds in Canada which have accepted this challenge: the national Mine Environment Neutral Drainage (MEND) program and the British Columbia Acid Mine Drainage (BC AMD) Task Force. This paper summarizes the activities of these two organizations

  4. Noncommutative black holes

    International Nuclear Information System (INIS)

    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

  5. 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.

  6. 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...

  7. 24 CFR 3280.610 - Drainage systems.

    Science.gov (United States)

    2010-04-01

    .... (a) General. (1) Each fixture directly connected to the drainage system shall be installed with a water seal trap (§ 3280.606(a)). (2) The drainage system shall be designed to provide an adequate... less than 3 inches inside diameter. (5) Preassembly of drain lines. Section(s) of the drain...

  8. Drainage Water Management for the Midwest

    Science.gov (United States)

    Subsurface tile drainage is an essential water management practice on many highly productive fields in the Midwest. However, nitrate carried in drainage water can lead to local water quality problems and contribute to hypoxia in the Gulf of Mexico, so strategies are needed to reduce the nitrate load...

  9. Identification and Quantification of Flavonoids and Phenolic Acids in Burr Parsley (Caucalis platycarpos L.), Using High-Performance Liquid Chromatography with Diode Array Detection and Electrospray Ionization Mass Spectrometry

    OpenAIRE

    Ana Mornar; Nikola Kujundžić; Biljana Nigović; Franz Bucar; Željan Maleš; Ana Plazonić

    2009-01-01

    A sensitive method coupling high-performance liquid chromatography (HPLC) with diode-array detector (DAD) and electrospray ionization mass spectrometry (MS) was optimized for the separation and identification of phenolic acids, flavonoid glycosides and flavonoid aglycones in the extract of burr parsley (Caucalis platycarpos L.). Fragmentation behavior of flavonoid glycosides and phenolic acids were investigated using ion trap mass spectrometry in negative electrospray ionization. The MS, MSn ...

  10. 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, or...

  11. Percutaneous biliary drainage and stenting

    International Nuclear Information System (INIS)

    Full text: Percutaneous transhepatic cholangiography (PTC) is an X-ray or US guided procedure that involves the injection of a contrast material directly into the bile ducts inside the liver to produce pictures of them. If a blockage or narrowing is found, additional procedures may be performed: 1. insertion of a catheter to drain excess bile out of the body or both - internal and external; 2. plastic endoprothesis placement; 3. self-expandable metal stents placement to help open bile ducts or to bypass an obstruction and allow fluids to drain. Current percutaneous biliary interventions include percutaneous transhepatic cholangiography (PTC) and biliary drainage to manage benign and malignant obstructions. Internal biliary stents are either plastic or metallic, and various types of each kind are available. Internal biliary stents have several advantages. An external tube can be uncomfortable and have a psychological disadvantage. An internal stent prevents the problems related to external catheters, for example, pericatheter leakage of bile and the need for daily flushing. The disadvantages include having to perform endoscopic retrograde cholangiopancreatography (ERCP) or new PTC procedures to obtain access in case of stent obstruction. Better patency rates are reported with metallic than with plastic stents in cases of malignant obstruction, though no effect on survival is noted. Plastic internal stents are the cheapest but reportedly prone to migration. Metallic stents are generally not used in the treatment of benign disease because studies have shown poor long-term patency rates. Limited applications may include the treatment of patients who are poor surgical candidates or of those in whom surgical treatment fails. Most postoperative strictures are treated surgically, though endoscopic and (less commonly) percutaneous placement of nonmetallic stents has increasingly been used in the past few years. Now there are some reports about use of biodegradable biliary

  12. Dynamics of black holes

    OpenAIRE

    Hayward, Sean A.

    2008-01-01

    This is a review of current theory of black-hole dynamics, concentrating on the framework in terms of trapping horizons. Summaries are given of the history, the classical theory of black holes, the defining ideas of dynamical black holes, the basic laws, conservation laws for energy and angular momentum, other physical quantities and the limit of local equilibrium. Some new material concerns how processes such as black-hole evaporation and coalescence might be described by a single trapping h...

  13. 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.

  14. Black holes without firewalls

    Science.gov (United States)

    Larjo, Klaus; Lowe, David A.; Thorlacius, Larus

    2013-05-01

    The postulates of black hole complementarity do not imply a firewall for infalling observers at a black hole horizon. The dynamics of the stretched horizon, that scrambles and reemits information, determines whether infalling observers experience anything out of the ordinary when entering a large black hole. In particular, there is no firewall if the stretched horizon degrees of freedom retain information for a time of the order of the black hole scrambling time.

  15. Solar system for soil drainage

    International Nuclear Information System (INIS)

    The paper reviews solar system for drainage of the cultivable agricultural surfaces which can be situated near the rivers in plains. These are usually very fertile surfaces which cannot be cultivated die to constant presence of the water. Using such solar systems should increase the percentage of cultivable surfaces. These systems can also be installed on the cultivable agricultural surfaces, where the water surfaces or so called still waters appear, which make impossible the application of agritechnical measures on these surfaces, significantly decreasing crops and creating conditions for the growth of pond plants and animals. Increasing the percentage of cultivable agricultural surfaces would increase national agricultural income. At the same time, increasing the percentage of cultivable agricultural surfaces decreases the surfaces of unhealthy bog, swamp and marshland soils, where many insect breed. They are the cause for soil spraying from the air, which causes the pollution of environment. Solar systems do not pollute the environment because they use solar energy as the purest source of energy. Their usage has special significance in the places where there is no electricity distribution network

  16. Preliminary Report on the Sny Drainage District

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — This report deals with the Sny River drainage in the Mississippi River and its management. The Sny bottoms will remain a major wildlife area in this portion of...

  17. 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.

  18. 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.

  19. Stuffed Black Holes

    CERN Document Server

    Arbona, A; Carot, J; Mas, L; Massó, J; Stela, J

    1998-01-01

    Initial data corresponding to spacetimes containing black holes are considered in the time symmetric case. The solutions are obtained by matching across the apparent horizon different, conformally flat, spatial metrics. The exterior metric is the vacuum solution obtained by the well known conformal imaging method. The interior metric for every black hole is regular everywhere and corresponds to a positive energy density. The resulting matched solutions cover then the whole initial (Cauchy) hypersurface, without any singularity, and can be useful for numerical applications. The simpler cases of one black hole (Schwarzschild data) or two identical black holes (Misner data) are explicitly solved. A procedure for extending this construction to the multiple black hole case is also given, and it is shown to work for all time symmetric vacuum solutions obtained by the conformal imaging method. The numerical evolution of one such 'stuffed' black hole is compared with that of a pure vacuum or 'plain' black hole in the...

  20. Hole history, rotary hole DC-3

    Energy Technology Data Exchange (ETDEWEB)

    1977-10-01

    Purpose of hole DC-3 was to drill into the Umtanum basalt flow using both conventional rotary and core drilling methods. The borehole is to be utilized for geophysical logging, future hydrological testing, and the future installation of a borehole laboratory for long-term pressure, seismic, and moisture migration or accumulation recording in the Umtanum basalt flow in support of the Basalt Waste Isolation Program. Hole DC-3 is located east of the 200 West barricaded area on the Hanford reservation.

  1. Hole history, rotary hole DC-3

    International Nuclear Information System (INIS)

    Purpose of hole DC-3 was to drill into the Umtanum basalt flow using both conventional rotary and core drilling methods. The borehole is to be utilized for geophysical logging, future hydrological testing, and the future installation of a borehole laboratory for long-term pressure, seismic, and moisture migration or accumulation recording in the Umtanum basalt flow in support of the Basalt Waste Isolation Program. Hole DC-3 is located east of the 200 West barricaded area on the Hanford reservation

  2. Failures and complications of thoracic drainage

    Directory of Open Access Journals (Sweden)

    Đorđević Ivana

    2006-01-01

    Full Text Available Background/Aim. Thoracic drainage is a surgical procedure for introducing a drain into the pleural space to drain its contents. Using this method, the pleura is discharged and set to the physiological state which enables the reexpansion of the lungs. The aim of the study was to prove that the use of modern principles and protocols of thoracic drainage significantly reduces the occurrence of failures and complications, rendering the treatment more efficient. Methods. The study included 967 patients treated by thoracic drainage within the period from January 1, 1989 to June 1, 2000. The studied patients were divided into 2 groups: group A of 463 patients treated in the period from January 1, 1989 to December 31, 1994 in whom 386 pleural drainage (83.36% were performed, and group B of 602 patients treated form January 1, 1995 to June 1, 2000 in whom 581 pleural drainage (96.51% were performed. The patients of the group A were drained using the classical standards of thoracic drainage by the general surgeons. The patients of the group B, however, were drained using the modern standards of thoracic drainage by the thoracic surgeons, and the general surgeons trained for this kind of the surgery. Results. The study showed that better results were achieved in the treatment of the patients from the group B. The total incidence of the failures and complications of thoracic drainage decreased from 36.52% (group A to 12.73% (group B. The mean length of hospitalization of the patients without complications in the group A was 19.5 days versus 10 days in the group B. The mean length of the treatment of the patients with failures and complications of the drainage in the group A was 33.5 days versus 17.5 days in the group B. Conclusion. The shorter length of hospitalization and the lower morbidity of the studied patients were considered to be the result of the correct treatment using modern principles of thoracic drainage, a suitable surgical technique, and a

  3. Endoscopic ultrasound-guided drainage of pancreatic pseudocysts

    OpenAIRE

    Săftoiu, 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, or surgical drainage. The aim of this review is to assess critically the current literature concerning EUS-guided pseudocyst drainage and to review the place of the procedure in the clinical decision ma...

  4. Stimulated Black Hole Evaporation

    CERN Document Server

    Spaans, Marco

    2016-01-01

    Black holes are extreme expressions of gravity. Their existence is predicted by Einstein's theory of general relativity and is supported by observations. Black holes obey quantum mechanics and evaporate spontaneously. Here it is shown that a mass rate $R_f\\sim 3\\times 10^{-8} (M_0/M)^{1/2}$ $M_0$ yr$^{-1}$ onto the horizon of a black hole with mass $M$ (in units of solar mass $M_0$) stimulates a black hole into rapid evaporation. Specifically, $\\sim 3 M_0$ black holes can emit a large fraction of their mass, and explode, in $M/R_f \\sim 3\\times 10^7 (M/M_0)^{3/2}$ yr. These stimulated black holes radiate a spectral line power $P \\sim 2\\times 10^{39} (M_0/M)^{1/2}$ erg s$^{-1}$, at a wavelength $\\lambda \\sim 3\\times 10^5 (M/M_0)$ cm. This prediction can be observationally verified.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. [Appropriate Biliary Drainage Methods for Unresectable Cholangiocarcinomas].

    Science.gov (United States)

    Oishi, Tatsurou; Kanemoto, Yoshiaki; Yoshioka, Yuuta; Sawada, Ryuuichirou; Sekine, Sachi; Miyanaga, Hiroto; Sakahira, Hideki; Takahashi, Hironori; Miyamoto, Katsufumi; Koyama, Takashi

    2015-11-01

    We investigated the efficacy of different biliary drainage methods for the treatment of unresectable cholangiocarcinomas. We performed a retrospective study of 28 patients with unresectable cholangiocarcinomas who underwent biliary drainage at our hospital between January 2008 and June 2014 to compare the incidence of post-drainage stent dysfunction (SD) and reintervention (RI) for SD according to primary drainage method, lesion site, and complication status (the presence or absence of cholangitis). The duration of stent patency was compared between the different stent types. No significant differences in the incidence of SD and RI were found according to primary drainage methods, lesion site, or the presence or absence of cholangitis. The mean durations of stent patency for plastic and metal stents were 2.7 months and 7.4 months, respectively, suggesting that metal stents should be selected when the estimated prognosis is ≥2 months. Furthermore, metal stent placement, rather than the additional placement of plastic stents, should be considered a feasible option in cases of SD. PMID:26805093

  10. Considerations regarding the work preceding the mining of lignite strata by means of big hole drilling

    Energy Technology Data Exchange (ETDEWEB)

    Avram, L.; Micu, I.

    1984-07-01

    The authors present the basic elements which have to be preliminarily estimated with a view to the big hole drilling of high quality. Based on the results, numerous problems raised by the growing rhythm of the drainage of the aquiferous formations, are solved. 4 references.

  11. 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.

  12. Evidence for black holes.

    Science.gov (United States)

    Begelman, Mitchell C

    2003-06-20

    Black holes are common objects in the universe. Each galaxy contains large numbers-perhaps millions-of stellar-mass black holes, each the remnant of a massive star. In addition, nearly every galaxy contains a supermassive black hole at its center, with a mass ranging from millions to billions of solar masses. This review discusses the demographics of black holes, the ways in which they interact with their environment, factors that may regulate their formation and growth, and progress toward determining whether these objects really warp spacetime as predicted by the general theory of relativity. PMID:12817138

  13. 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.

  14. A Black Hole Levitron

    CERN Document Server

    Arsiwalla, Xerxes D

    2009-01-01

    We study the problem of spatially stabilising four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes kept in external fields we find that taking a continuum limit of Denef et al's multi-center solutions provides a supergravity description of such backgrounds within which a black hole can be trapped in a given volume. This is realised by levitating a black hole over a magnetic dipole base. We comment on how such a construction resembles a mechanical Levitron.

  15. Deforming regular black holes

    CERN Document Server

    Neves, J C S

    2015-01-01

    In this work, we have deformed regular black holes which possess a general mass term described by a function which generalizes the Bardeen and Hayward mass terms. Using linear constraints in the energy-momentum tensor, the solutions are either regular or singular. That is, with this approach, it is possible to generate singular black holes from regular black holes and vice versa. Moreover, contrary to the Bardeen and Hayward regular solutions, the regular deformed metrics may violate the weak energy condition despite the presence of the spherical symmetry. Some comments on accretion of deformed black holes in cosmological scenarios are made.

  16. Black holes and beyond

    International Nuclear Information System (INIS)

    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 instance, the UK

  17. Mine Drainage and Oil Sand Water.

    Science.gov (United States)

    Wei, Xinchao; Wolfe, F Andrew; Li, Yanjun

    2015-10-01

    Mine drainage from the mining of mineral resources (coal, metals, oil sand, or industrial minerals) remains as a persistent environmental problem. This review summarizes the scientific literature published in 2014 on the technical issues related to mine drainage or mine water in active and abandoned coal/hard rock mining sites or waste spoil piles. Also included in this review is the water from oil sand operations. This review is divided into the four sections: 1) mine drainage characterization, 2) prediction and environmental impact, 3) treatment technologies, 4) oil sand water. Many papers presented in this review address more than one aspect and different sections should not be regarded as being mutuallyexclusive or all-inclusive.

  18. Bronchoscopic drainage of a malignant lung abscess.

    Science.gov (United States)

    Katsenos, Stamatis; Psathakis, Konstantinos; Chatzivasiloglou, Fotini; Antonogiannaki, Elvira-Markela; Psara, Anthoula; Tsintiris, Konstantinos

    2015-04-01

    Bronchoscopic drainage of a pyogenic lung abscess is an established therapeutic approach in selected patients in whom conventional antibiotic therapy fails. This intervention has also been undertaken in patients with abscess owing to underlying lung cancer and prior combined radiochemotherapy. However, this procedure has rarely been performed in cavitary lesions of advanced tumor origin before initiating any chemotherapy/radiotherapy scheme. Herein, we describe a case of a 68-year-old woman with lung adenocarcinoma stage IIIB, who underwent bronchoscopic drainage of necrotizing tumor lesion, thus improving her initial poor clinical condition and rendering other treatment modalities, such as radiotherapy, more effective and beneficial. Bronchoscopic drainage of a symptomatic cancerous lung abscess should be considered as an alternative and palliative treatment approach in patients with advanced inoperable non-small cell lung cancer. PMID:25887013

  19. Chemical evolution of coal mine drainage in a non-acid producing environment, Wasatch Plateau, Utah, USA

    Science.gov (United States)

    Mayo, A. L.; Petersen, E. C.; Kravits, C.

    2000-09-01

    The causes and problems of coal mine drainage, particularly acid mine drainage, in the Eastern and Interior Coal Provinces of the United States are well documented. West of the Mississippi River, where coal mines account for about 45% of total US coal production and where acid mine drainage is rare, the chemical evolution of coal mine drainage is less well documented and understood. In this investigation, we have used solute and isotopic compositions of non-evolved inflow groundwater and evolved mine discharge water to quantify the chemical evolution of mine discharge water in a western underground coal mine. Water enters the mine from fractures and roof bolt holes, which intercept groundwater in the overlying rock. Carbon-14, and 3H data indicate that these waters recharged between 12,000 and 19,500 years ago. The TDS and solute compositions of roof drip waters are spatially zoned and TDS concentrations range from about 300 to 550 mg l -1. After the water encounters minerals and other substances in the mine, the chemical differences between various mine regions become more pronounced and the TDS of mine drainage water increases to about 850 mg l -1. The TDS of mine drainage is related to water-rock ratios. Mine drainage issuing from the older mined areas, where water-rock ratios are low, has the greatest TDS. Geochemical and isotopic mass balance calculations were performed to quantify chemical reactions in the mine, and to identify sources contributing to the TDS of mine drainage. Chemical reaction pathways evaluated include pyrite oxidation, dissolution of native and rock dust gypsum, dissolution of calcite and dolomite, precipitation of calcite, ion exchange, precipitation of iron hydroxide, and organic decomposition of mining machine emulsion fluid. Solute and isotopic mass transfer reaction calculations demonstrate that the oxidation of pyrite triggers a series of cascading in-mine chemical reactions that are the primary cause of the elevated TDS of mine

  20. Percutaneous transhepatic biliary drainage for hilar cholangiocarcinoma

    International Nuclear Information System (INIS)

    Objective: To evaluate the effect of PTBD in treating malignant biliary obstruction caused by hilar cholangiocarcinoma. Methods: We retrospectively analyzed the data of 103 patients(M:62,F:41)with malignant obstructive jaundice caused by hilar cholangiocarcinoma. After taking percutaneous transhepatic cholangiography, metallic stent or plastic external catheter or external-internal catheter for drainage was deployed and then followed up was undertaken with clinical and radiographic evaluation and laboratory. examination. Results: All patients went though PTBD successfully (100%). According to Bismuth classification, all 103 cases consisted of I type(N=30), II type (N=30), III type (N=26) and IV type (N=17). Thirty-nine cases were placed with 47 stents and 64 eases with drainage tubes. 4 cases installed two stems for bilateral drainage, 2 cases installed two stents because of long segmental strictures with stent in stent, 1 case was placed with three stents, and 3 cases installed stent and plastic catheter together. Sixty-four cases received plastic catheters in this series, 35 cases installed two or more catheters for bilateral drainage, 28 cases installed external and internal drainage catheters, 12 eases installed external drainage catheters, and 24 eases installed both of them. There were 17 patients involving incorporative infection before procedure, 13 cases cured after procedure, and 15 new patients got inflammation after procedure. 13 cases showed increase of amylase (from May, 2004), 8 eases had bloody bile drainage and 1 case with pyloric obstruction. Total serum bilirubin reduced from (386 ± 162) μmol/L to (161 ± 117) μmol/L, (P<0.01) short term curative effect was related with the type of hilar cholangiocarcinoma. The survival time was 186 days(median), and 1, 3, 6, 12 month survival rate were 89.9%, 75.3%, 59.6%, 16.9%, respectively. Conclusion: Percutaneous transhepatic bile drainage is a safe and effective palliative therapy of malignant

  1. Hole-hole propagation and saturation

    International Nuclear Information System (INIS)

    Ladder contributions to the effective interaction are calculated with inclusion of hole-hole (hh) propagation to all orders. For a correct calculation of the self-energy resulting from the ladder-summed effective interaction, ΓL, dispersion relations are used numerically. The single-particle (sp) energy is calculated self-consistently from the real on-shell self-energy. The contribution of the hh terms leads to a repulsive contribution to the energy per particle which increases with density. This saturation mechanism has not been identified previously and results are presented for the ν2 homework potential. (orig.)

  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. Noncommutative Singular Black Holes

    International Nuclear Information System (INIS)

    In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t - r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.

  5. Noncommutative Singular Black Holes

    Science.gov (United States)

    Hamid Mehdipour, S.

    2010-11-01

    In this paper, applying the method of coordinate coherent states to describe a noncommutative model of Vaidya black holes leads to an exact (t — r) dependence of solution in terms of the noncommutative parameter σ. In this setup, there is no black hole remnant at long times.

  6. 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.

  7. 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…

  8. 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.

  9. Fluctuating Black Hole Horizons

    CERN Document Server

    Mei, Jianwei

    2013-01-01

    In this paper we treat the black hole horizon as a physical boundary to the spacetime and study its dynamics following from the Gibbons-Hawking-York boundary term. Using the Kerr black hole as an example we derive an effective action that describes, in the large wave number limit, a massless Klein-Gordon field living on the average location of the boundary. Complete solutions can be found in the small rotation limit of the black hole. The formulation suggests that the boundary can be treated in the same way as any other matter contributions. In particular, the angular momentum of the boundary matches exactly with that of the black hole, suggesting an interesting possibility that all charges (including the entropy) of the black hole are carried by the boundary. Using this as input, we derive predictions on the Planck scale properties of the boundary.

  10. 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.

  11. Evolution of massive black holes

    OpenAIRE

    Volonteri, Marta

    2007-01-01

    Supermassive black holes are nowadays believed to reside in most local galaxies. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. I briefly review here some of the physical processes that are conducive to the evolution of the massive black hole population. I'll discuss black hole formation processes that are likely to place at early cosmic epochs, and how massive black hole evolve in a hierarchical Universe...

  12. 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.

  13. Transanal Endoscopic Drainage of Abdominopelvic Sepsis

    OpenAIRE

    Abbas, Maher A; Falls, Garietta

    2008-01-01

    Natural Orifice Transluminal Endoscopic Surgery (NOTES) is an evolving experimental field exploring the technical feasibility and outcome of therapeutic interventions performed through the natural orifices of the body. The knowledge accumulating in NOTES is the result of animal experimentation and ongoing early clinical experience in humans. In this report we describe a patient treated with transanal endoscopic drainage of postoperative abdominopelvic sepsis.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Delayed Macular Hole Closure

    Directory of Open Access Journals (Sweden)

    Peter Distelmaier

    2014-04-01

    Full Text Available Purpose: The presented case raises questions regarding the favorable scheduling of planned postoperative care and the ideal observation interval to decide for reoperations in macular hole surgery. Furthermore a discussion about the use of short- and long-acting gas tamponades in macular hole surgery is encouraged. Methods: We present an interventional case report and a short review of the pertinent literature. Results: We report a case of spontaneous delayed macular hole closure after vitreoretinal surgery had been performed initially without the expected success. A 73-year-old male Caucasian patient presented at our clinic with a stage 2 macular hole in his left eye. He underwent 23-gauge pars plana vitrectomy and internal limiting membrane peeling with a 20% C2F6-gas tamponade. Sixteen days after the procedure, an OCT scan revealed a persistent stage 2 macular hole, and the patient was scheduled for reoperation. Surprisingly, at the date of planned surgery, which was another 11 days later, the macular hole had resolved spontaneously without any further intervention. Conclusions: So far no common opinion exists regarding the use of short- or long-acting gas in macular hole surgery. Our case of delayed macular hole closure after complete resorption of the gas tamponade raises questions about the need and duration of strict prone positioning after surgery. Furthermore short-acting gas might be as efficient as long-acting gas. We suggest to wait with a second intervention at least 4 weeks after the initial surgery, since a delayed macular hole closure is possible.

  19. Antarctic Ozone Hole, 2000

    Science.gov (United States)

    2002-01-01

    Each spring the ozone layer over Antarctica nearly disappears, forming a 'hole' over the entire continent. The hole is created by the interaction of some man-made chemicals-freon, for example-with Antarctica's unique weather patterns and extremely cold temperatures. Ozone in the stratosphere absorbs ultraviolet radiation from the sun, thereby protecting living things. Since the ozone hole was discovered many of the chemicals that destroy ozone have been banned, but they will remain in the atmosphere for decades. In 2000, the ozone hole grew quicker than usual and exceptionally large. By the first week in September the hole was the largest ever-11.4 million square miles. The top image shows the average total column ozone values over Antarctica for September 2000. (Total column ozone is the amount of ozone from the ground to the top of the atmosphere. A relatively typical measurement of 300 Dobson Units is equivalent to a layer of ozone 0.12 inches thick on the Earth's surface. Levels below 220 Dobson Units are considered to be significant ozone depletion.) The record-breaking hole is likely the result of lower than average ozone levels during the Antarctic fall and winter, and exceptionally cold temperatures. In October, however (bottom image), the hole shrank dramatically, much more quickly than usual. By the end of October, the hole was only one-third of it's previous size. In a typical year, the ozone hole does not collapse until the end of November. NASA scientists were surprised by this early shrinking and speculate it is related to the region's weather. Global ozone levels are measured by the Total Ozone Mapping Spectrometer (TOMS). For more information about ozone, read the Earth Observatory's ozone fact sheet, view global ozone data and see these ozone images. Images by Greg Shirah, NASA GSFC Scientific Visualization Studio.

  20. Scalarized Hairy Black Holes

    CERN Document Server

    Kleihaus, Burkhard; Yazadjiev, Stoytcho

    2015-01-01

    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 ordinary hairy black holes. 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.

  1. Noncommutative Solitonic Black Hole

    CERN Document Server

    Chang-Young, Ee; Lee, Daeho; Lee, Youngone

    2012-01-01

    We investigate solitonic black hole solutions in three dimensional noncommutative spacetime. We do this in gravity with negative cosmological constant coupled to a scalar field using the Moyal product expanded up to first order in the noncommutativity parameter in the two noncommutative spatial directions. By numerical simulation we look for black hole solutions by increasing the non- commutativity parameter value starting from regular solutions with vanishing noncommutativity. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value.

  2. 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.

  3. 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.

  4. 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

  5. Scalarized hairy black holes

    International Nuclear Information System (INIS)

    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

  6. Processing method for drainage-containing ethanol amine

    International Nuclear Information System (INIS)

    Ethanol amine is decomposed by aerobically acting Pseudomonas sp. When drainage contains hydrazine, copper sulfate and hydrogen peroxide are added to the drainage under exposed condition to remove hydrazine as a pretreatment of the decomposing step. With such procedures, ethanol amine in the drainage can be processed efficiently. (T.M.)

  7. 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...

  8. Introducing the Black Hole

    Science.gov (United States)

    Ruffini, Remo; Wheeler, John A.

    1971-01-01

    discusses the cosmology theory of a black hole, a region where an object loses its identity, but mass, charge, and momentum are conserved. Include are three possible formation processes, theorized properties, and three way they might eventually be detected. (DS)

  9. 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.

  10. Cosmological Black Holes

    OpenAIRE

    Stornaiolo, Cosimo

    2001-01-01

    In this paper we propose a model for the formation of the cosmological voids. We show that cosmological voids can form directly after the collapse of extremely large wavelength perturbations into low-density black holes or cosmological black holes (CBH). Consequently the voids are formed by the comoving expansion of the matter that surrounds the collapsed perturbation. It follows that the universe evolves, in first approximation, according to the Einstein-Straus cosmological model. We discuss...

  11. Cosmic Black Holes

    OpenAIRE

    Ahn, Eun-Joo; Cavaglia, Marco

    2003-01-01

    Production of high-energy gravitational objects is a common feature of gravitational theories. The primordial universe is a natural setting for the creation of black holes and other nonperturbative gravitational entities. Cosmic black holes can be used to probe physical properties of the very early universe which would usually require the knowledge of the theory of quantum gravity. They may be the only tool to explore thermalisation of the early universe. Whereas the creation of cosmic black ...

  12. Quantum black holes

    International Nuclear Information System (INIS)

    No particle theory can be complete without gravity. Einstein's theory of gravity is of the Euler-Lagrange form, but standard quantization procedure fails. In quantum gravity the higher order interactions have a dimensionality different form the fundamental ones, because Newton's constant G has dimensions and the renormalization procedure fails. Another problem with quantum gravity is even more mysterious. Suppose that we had regularized the gravitational forces at the small distance end in the way that the weak intermediate vector boson regularized the fundamental 4-fermion interaction vertex of the weak interactions. Then what we discover is that the gravitational forces are unstable. Given sufficiently large amount of matter, it can collapse under its own weight. Classical general relativity tells us what will happen: a black hole is formed. But how is this formulated in quantum theory. S. Hawking observed that when a field theory is quantized in the background metric of a black hole, the black hole actually emits particles in a completely random thermal way. Apparently black holes are just another form of matter unstable against Hawking decay. Unfortunately this picture cannot be complete. The problem is that the quantum version of black holes has infinite phase space, and other symptoms of a run-away solution. Black holes are the heaviest and most compact forms of matter that can be imagined. A complete particle theory can have nothing but a spectrum of black-hole like objects at it high-energy end. This is why it is believed that a resolution of the black hole problem will in time disclose the complete small-distance structure of our world. 6 references

  13. 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.

  14. On Noncommutative Black Holes Thermodynamics

    CERN Document Server

    Faizal, Mir; Ulhoa, S C

    2015-01-01

    In this paper, we will analyze noncommutative deformation of the Schwarzschild black holes and Kerr black holes. We will perform our analysis by relating the commutative and the noncommutative metrics using an Moyal product. We will also analyze the thermodynamics of these noncommutative black hole solutions. We will explicitly derive expression for the corrected entropy and temperature of these black hole solutions.

  15. The Thermodynamics of Black Holes

    Directory of Open Access Journals (Sweden)

    Wald Robert M.

    2001-01-01

    Full Text Available We review the present status of black hole thermodynamics. Our review includes discussion of classical black hole thermodynamics, Hawking radiation from black holes, the generalized second law, and the issue of entropy bounds. A brief survey also is given of approaches to the calculation of black hole entropy. We conclude with a discussion of some unresolved open issues.

  16. 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.

  17. 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...

  18. Topics in black hole evaporation

    International Nuclear Information System (INIS)

    Two major aspects of particle creation by gravitational fields of black holes are studied: the neutrino emission from rotating black holes; and interactions between scalar particles emitted by a black hole. Neutrino emission is investigated under three topics: The asymmetry of the angular dependence of neutrino emission from rotating black holes; the production of a local matter excess by rotating black holes in a baryon symmetric universe; and cosmological magnetic field generation by neutrinos from evaporating black holes. Finally the author studies the effects of interactions on the black hole evaporation process

  19. 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)

  20. 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.

  1. Bilothorax as a complication of percutaneous transhepatic biliary drainage.

    Science.gov (United States)

    Sano, Atsushi; Yotsumoto, Takuma

    2016-01-01

    We report two cases of bilothorax that occurred as a complication of percutaneous transhepatic biliary drainage. In an 86-year-old woman who had undergone percutaneous transhepatic biliary drainage for obstructive jaundice, bilothorax occurred after accidental removal of the tube. She recovered with chest drainage only. An 83-year-old man who had undergone percutaneous transhepatic biliary drainage for cholecystitis developed bilothorax with infection. He recovered with thoracoscopic curettage. Although bilothorax is a rare complication of percutaneous transhepatic biliary drainage, appropriate diagnosis and prompt treatment is important, especially when bilothorax is accompanied by infection. PMID:26294694

  2. 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

  3. 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....

  4. Geochemical drainage survey of central Argyll, Scotland

    OpenAIRE

    Coats, J.S.; Tandy, B.C.; Michie, U.McL

    1982-01-01

    A reconnaissance geochemical drainage survey of 720 km2 of Dalradian outcrop in central Argyll identified base-metal anomalies in the Pyrite Zone, Ardrishaig Phyllites, Loch Tay Limestone and the Green Beds. Faulting and igneous intrusion modified the distribution of metal content within these formations. In the results of the reconnaissance survey, copper reached maxima of 170 ppm and 1454 ppm in stream sediments and panned concentrates respectively; lead 1050 ppm ...

  5. Drainage basins and channel incision on Mars

    OpenAIRE

    Aharonson, Oded; Zuber, Maria T.; Rothman, Daniel H.; Schorghofer, Norbert; Whipple, Kelin X.

    2002-01-01

    Measurements acquired by the Mars Orbiter Laser Altimeter on board the Mars Global Surveyor indicate that large drainage systems on Mars have geomorphic characteristics inconsistent with prolonged erosion by surface runoff. We find the topography has not evolved to an expected equilibrium terrain form, even in areas where runoff incision has been previously interpreted. By analogy with terrestrial examples, groundwater sapping may have played an important role in the incision. Longitudinally ...

  6. Congresverslag Urban Drainage Modelling 9 te Belgrado

    OpenAIRE

    Rombouts, P.M.M.; Clemens, F.H.L.R.; Ten Veldhuis, J.A.E.; Pothof, I.W.M.; Langeveld, J.G.

    2012-01-01

    Van 3 tot en met 7 september 2012 is de negende Urban Drainage Modelling conferentie gehouden in Belgrado, de hoofdstad van Seme. Hieronder volgt een verslag van de indrukken die zijn opgedaan in Servië en de belangrijkste, wetenschappelijke ontwikkelingen die aan de orde zijn gekomen. Het congres had een vol wetenschappelijk programma, mede doordat de organisatie ook graag de stad en het land wilde promoten.

  7. 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.

  8. Numerical simulations of drainage flows on Mars

    Science.gov (United States)

    Parish, Thomas R.; Howard, Alan D.

    1992-01-01

    Data collected by Viking Landers have shown that the meteorology of the near surface Martian environment is analogous to desertlike terrestrial conditions. Geological evidence such as dunes and frost streaks indicate that the surface wind is a potentially important factor in scouring of the martian landscape. In particular, the north polar basin shows erosional features that suggest katabatic wind convergence into broad valleys near the margin of the polar cap. The pattern of katabatic wind drainage off the north polar cap is similar to that observed on Earth over Antarctica or Greenland. The sensitivity is explored of Martian drainage flows to variations in terrain slope and diurnal heating using a numerical modeling approach. The model used is a 2-D sigma coordinate primitive equation system that has been used for simulations of Antarctic drainage flows. Prognostic equations include the flux forms of the horizontal scalar momentum equations, temperature, and continuity. Parameterization of both longwave (terrestrial) and shortwave (solar) radiation is included. Turbulent transfer of heat and momentum in the Martian atmosphere remains uncertain since relevant measurements are essentially nonexistent.

  9. 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

  10. 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.

  11. A STUDY OF VARIABLES CHARACTERIZING DRAINAGE PATTERNS IN RIVER NETWORKS

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2012-07-01

    Full Text Available In GIS and in terrain analysis, drainage systems are important components. Due to local topography and subsurface geology, a drainage system achieves a particular drainage pattern based on the form and texture of its network of stream channels and tributaries. Drainage pattern recognition helps to provide a qualitative description of the terrain for analysis and classification and is useful for terrain modelling and visualization and applications in environment. Much research has been done on the description of drainage patterns in geography and hydrology. However automatic drainage pattern recognition in river networks is not well developed. This paper introduces a method based on geometric quantitative indicators to recognize drainage patterns in a river network automatically. Experiment results are presented and discussed.

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

    International Nuclear Information System (INIS)

    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

  15. 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...

  16. 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.

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

    International Nuclear Information System (INIS)

    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

  18. 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.

  19. 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.

  20. 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.

  1. Black-hole astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Bender, P. [Univ. of Colorado, Boulder, CO (United States); Bloom, E. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Cominsky, L. [Sonoma State Univ., Rohnert Park, CA (United States). Dept. of Physics and Astronomy] [and others

    1995-07-01

    Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.

  2. Black Hole Bose Condensation

    Science.gov (United States)

    Vaz, Cenalo; Wijewardhana, L. C. R.

    2013-12-01

    General consensus on the nature of the degrees of freedom responsible for the black hole entropy remains elusive despite decades of effort dedicated to the problem. Different approaches to quantum gravity disagree in their description of the microstates and, more significantly, in the statistics used to count them. In some approaches (string theory, AdS/CFT) the elementary degrees of freedom are indistinguishable, whereas they must be treated as distinguishable in other approaches to quantum gravity (eg., LQG) in order to recover the Bekenstein-Hawking area-entropy law. However, different statistics will imply different behaviors of the black hole outside the thermodynamic limit. We illustrate this point by quantizing the Bañados-Teitelboim-Zanelli (BTZ) black hole, for which we argue that Bose condensation will occur leading to a "cold", stable remnant.

  3. 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. PMID:25768746

  4. Noncommutative black hole thermodynamics

    International Nuclear Information System (INIS)

    We give a general derivation, for any static spherically symmetric metric, of the relation Th=(K/2π) connecting the black hole temperature (Th) with the surface gravity (K), following the tunneling interpretation of Hawking radiation. This derivation is valid even beyond the semi-classical regime, i.e. when quantum effects are not negligible. The formalism is then applied to a spherically symmetric, stationary noncommutative Schwarzschild space-time. The effects of backreaction are also included. For such a black hole the Hawking temperature is computed in a closed form. A graphical analysis reveals interesting features regarding the variation of the Hawking temperature (including corrections due to noncommutativity and backreaction) with the small radius of the black hole. The entropy and tunneling rate valid for the leading order in the noncommutative parameter are calculated. We also show that the noncommutative Bekenstein-Hawking area law has the same functional form as the usual one

  5. Ozone Hole Over Antarctica

    Science.gov (United States)

    2002-01-01

    These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This 'ozone hole' has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Credit: Images by Greg Shirah, NASA Goddard Space Flight Center Scientific Visualization Studio

  6. Slowly balding black holes

    International Nuclear Information System (INIS)

    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 the 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 NB=eΦ∞/(πc(ℎ/2π)), where Φ∞≅2π2BNSRNS3/(PNSc) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. 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 balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  7. 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.

  8. 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.

  9. 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.

  10. Noncommutative solitonic black hole

    International Nuclear Information System (INIS)

    We investigate solitonic black hole solutions in three-dimensional noncommutative spacetime. We do this in gravity with a negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value. (paper)

  11. Noncommutative solitonic black hole

    Science.gov (United States)

    Chang-Young, Ee; Kimm, Kyoungtae; Lee, Daeho; Lee, Youngone

    2012-05-01

    We investigate solitonic black hole solutions in three-dimensional noncommutative spacetime. We do this in gravity with a negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find that even a regular soliton solution in the commutative case becomes a black hole solution when the noncommutativity parameter reaches a certain value.

  12. 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.

  13. Dancing with black holes

    CERN Document Server

    Aarseth, Sverre J

    2007-01-01

    We describe efforts over the last six years to implement regularization methods suitable for studying one or more interacting black holes by direct N-body simulations. Three different methods have been adapted to large-N systems: (i) Time-Transformed Leapfrog, (ii) Wheel-Spoke, and (iii) Algorithmic Regularization. These methods have been tried out with some success on GRAPE-type computers. Special emphasis has also been devoted to including post-Newtonian terms, with application to moderately massive black holes in stellar clusters. Some examples of simulations leading to coalescence by gravitational radiation will be presented to illustrate the practical usefulness of such methods.

  14. 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.

  15. 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.

  16. Black holes and quasiblack holes: Some history and remarks

    CERN Document Server

    Lemos, José P S

    2011-01-01

    A brief reference to the two Schwarzschild solutions and what Petrov had to say about them is given. Comments on how the Schwarzschild vacuum solution describes a black hole are also provided. Then we compare the properties, differences and similarities between black holes and quasiblack holes. Black holes are well known. Quasiblack hole is a new concept. A quasiblack hole, either nonextremal or extremal, can be broadly defined as the limiting configuration of a body when its boundary approaches the body's own gravitational radius (the quasihorizon). They are objects that are on the verge of being black holes but actually are distinct from them in many ways. We display some of their properties: there are infinite redshift whole regions; the curvature invariants remain perfectly regular everywhere, in the quasiblack hole limit; a free-falling observer finds in his own frame infinitely large tidal forces in the whole inner region, showing some form of degeneracy; outer and inner regions become mutually impenetr...

  17. 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

  18. 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. PMID:23263336

  19. Tunnelling from black holes and tunnelling into white holes

    Science.gov (United States)

    Chatterjee, Bhramar; Ghosh, A.; Mitra, P.

    2008-03-01

    Hawking radiation is nowadays being understood as tunnelling through black hole horizons. Here, the extension of the Hamilton-Jacobi approach to tunnelling for non-rotating and rotating black holes in different non-singular coordinate systems not only confirms this quantum emission from black holes but also reveals the new phenomenon of absorption into white holes by quantum mechanical tunnelling. The rôle of a boundary condition of total absorption or emission is also clarified.

  20. 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

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

    NARCIS (Netherlands)

    N.A. van der Gaag; S.M.M. de Castro; E.A.J. Rauws; M.J. Bruno; C.H.J. van Eijck; E.J. Kuipers; J.J.G.M. Gerritsen; J.P. Rutten; J.W. Greve; E.J. Hesselink; J.H.G. Klinkenbijl; I.H.M. Borel Rinkes; D. Boerma; B.A. Bonsing; C.J. van Laarhoven; F.J.G.M. Kubben; E. van der Harst; M.N. Sosef; K. Bosscha; I.H.J.T. de Hingh; L.T. de Wit; O.M. van Delden; O.R.C. Busch; T.M. van Gulik; P.M.M. Bossuyt; D.J. Gouma

    2007-01-01

    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 gen

  2. 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; 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

  3. Black holes and qubits

    CERN Document Server

    Duff, M J

    2012-01-01

    Quantum entanglement lies at the heart of quantum information theory, with applications to quantum computing, teleportation, cryptography and communication. In the apparently separate world of quantum gravity, the Hawking effect of radiating black holes has also occupied centre stage. Despite their apparent differences, it turns out that there is a correspondence between the two.

  4. 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.

  5. 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.

  6. 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.

  7. The black hole final state

    OpenAIRE

    Horowitz, Gary T.; Maldacena, Juan

    2003-01-01

    We propose that in quantum gravity one needs to impose a final state boundary condition at black hole singularities. This resolves the apparent contradiction between string theory and semiclassical arguments over whether black hole evaporation is unitary.

  8. 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.

  9. 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

  10. 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....

  11. Endoscopic Ultrasound-guided Bilio-pancreatic Drainage

    OpenAIRE

    Giovannini, Marc; Bories, Erwan; Téllez-Ávila, Félix I.

    2012-01-01

    The echoendoscopic biliary drainage is an option to treat obstructive jaundices when endoscopic retrograde cholangiopancreatography (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 sectorial array echoendoscopes in early 1990 brought a new approach to diagnostic and therapeu...

  12. Correlation of laboratory and installed drainage system solid transport measurements

    OpenAIRE

    Bokor, Shaun

    1982-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. The transport of solids in 'horizontal' above ground drainage pipes was the subject of an investigation, based upon the measurement of both sterile 'model' solid velocity and 'live' waste load velocity, aimed at the establishment of a sound basis for the development of a comprehensive empirical drainage design method linked directly to installed drainage system solid transport measurements...

  13. Urban drainage design and climate change adaptation decision making

    OpenAIRE

    Zhou, Qianqian; Arnbjerg-Nielsen, Karsten; Mikkelsen, Peter Steen; Nielsen, Susanne Balslev; Halsnæs, Kirsten

    2012-01-01

    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 century, the design objectives of urban drainage systems also include elements such as environmental protection and amenity values. Among the objectives, flood protection has received much attention...

  14. Black Hole Evaporation. A Survey

    OpenAIRE

    Benachenhou, Farid

    1994-01-01

    This thesis is a review of black hole evaporation with emphasis on recent results obtained for two dimensional black holes. First, the geometry of the most general stationary black hole in four dimensions is described and some classical quantities are defined. Then, a derivation of the spectrum of the radiation emitted during the evaporation is presented. In section four, a two dimensional model which has black hole solutions is introduced, the so-called CGHS model. These two dimensional blac...

  15. 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.

  16. Towards noncommutative quantum black holes

    International Nuclear Information System (INIS)

    In this paper we study noncommutative black holes. We use 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 the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole

  17. Towards Noncommutative Quantum Black Holes

    OpenAIRE

    Lopez-Dominguez, J. C.; Obregon, O.; Ramirez, C.; Sabido, M.

    2006-01-01

    In this paper we study noncommutative black holes. We use 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 the Hawking's temperature and entropy for the noncommutative Schwarzschild black hole.

  18. Foam drainage on a sloping weir.

    Science.gov (United States)

    Grassia, P; Neethling, S J; Cilliers, J J

    2002-08-01

    Foam drainage is considered in a froth flotation tank with a sloping weir. The drainage is shown to be gravity dominated in most of the foam, except for thin boundary layers at the base of the froth, and along the sloping weir. The mathematical reason for the boundary layers is that capillary suction is a much weaker effect than gravity, but cannot be ignored altogether, because it represents a singular perturbation. The relative weakness of capillary suction with respect to gravity is represented by a key dimensionless parameter, denoted K, which satisfies Kbulk of the flotation tank. The liquid volume fraction in the jet is likewise O(K(-2/3)) larger than that in the bulk. Across the jet, the foam exhibits a known profile of liquid fraction vs. distance from the weir: this is known as the equilibrium profile. The foam requires a distance equivalent to O(K(4/3)) weir lengths to dry out significantly from the wetness value on the weir, but a larger O(K) distance to fall back to a wetness comparable with that in the bulk of the froth. PMID:15015124

  19. 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.

  20. Slowly balding black holes

    Science.gov (United States)

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-10-01

    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 the 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 NB=eΦ∞/(πcℏ), where Φ∞≈2π2BNSRNS3/(PNSc) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. 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 balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  1. 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.

  2. Warped products and black holes

    International Nuclear Information System (INIS)

    We apply the warped product space-time scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstroem-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes

  3. Warped products and black holes

    CERN Document Server

    Hong, S T

    2005-01-01

    We apply the warped product spacetime scheme to the Banados-Teitelboim-Zanelli black holes and the Reissner-Nordstr\\"om-anti-de Sitter black hole to investigate their interior solutions in terms of warped products. It is shown that there exist no discontinuities of the Ricci and Einstein curvatures across event horizons of these black holes.

  4. 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.

  5. 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.

  6. Observational Evidence for Black Holes

    OpenAIRE

    Narayan, Ramesh; McClintock, Jeffrey E.

    2013-01-01

    Astronomers have discovered two populations of black holes: (i) stellar-mass black holes with masses in the range 5 to 30 solar masses, millions of which are present in each galaxy in the universe, and (ii) supermassive black holes with masses in the range 10^6 to 10^{10} solar masses, one each in the nucleus of every galaxy. There is strong circumstantial evidence that all these objects are true black holes with event horizons. The measured masses of supermassive black hole are strongly corr...

  7. 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

  8. Prisons of light : black holes

    Science.gov (United States)

    Ferguson, Kitty

    What is a black hole? Could we survive a visit to one -- perhaps even venture inside? Have we yet discovered any real black holes? And what do black holes teach us about the mysteries of our Universe? These are just a few of the tantalizing questions examined in this tour-de-force, jargon-free review of one of the most fascinating topics in modern science. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light - Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.

  9. Point mass Cosmological Black Holes

    CERN Document Server

    Firouzjaee, Javad T

    2016-01-01

    Real black holes in the universe are located in the expanding accelerating background which are called the cosmological black holes. Hence, it is necessary to model these black holes in the cosmological background where the dark energy is the dominant energy. In this paper, we argue that most of the dynamical cosmological black holes can be modeled by point mass cosmological black holes. Considering the de Sitter background for the accelerating universe, we present the point mass cosmological background in the cosmological de Sitter space time. Our work also includes the point mass black holes which have charge and angular momentum. We study the mass, horizons, redshift structure and geodesics properties for these black holes.

  10. 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.

  11. Black Holes and Fourfolds

    CERN Document Server

    Bena, Iosif; Vercnocke, Bert

    2012-01-01

    We establish the relation between the structure governing supersymmetric and non-supersymmetric four- and five-dimensional black holes and multicenter solutions and Calabi-Yau flux compactifications of M-theory and type IIB string theory. We find that the known BPS and almost-BPS multicenter black hole solutions can be interpreted as GKP compactifications with (2,1) and (0,3) imaginary self-dual flux. We also show that the most general GKP compactification leads to new classes of BPS and non-BPS multicenter solutions. We explore how these solutions fit into N=2 truncations, and elucidate how supersymmetry becomes camouflaged. As a necessary tool in our exploration we show how the fields in the largest N=2 truncation fit inside the six-torus compactification of eleven-dimensional supergravity.

  12. Shape of black holes

    CERN Document Server

    Clement, María E Gabach

    2015-01-01

    It is well known that celestial bodies tend to be spherical due to gravity and that rotation produces deviations from this sphericity. We discuss what is known and expected about the shape of black holes' horizons from their formation to their final, stationary state. We present some recent results showing that black hole rotation indeed manifests in the widening of their central regions, limits their global shapes and enforces their whole geometry to be close to the extreme Kerr horizon geometry at almost maximal rotation speed. The results depend only on the horizon area and angular momentum. In particular they are entirely independent of the surrounding geometry of the spacetime and of the presence of matter satisfying the strong energy condition. We also discuss the the relation of this result with the Hoop conjecture.

  13. 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.

  14. Photon Black Holes

    CERN Document Server

    Hernández, X; Mendoza, S; Sussman, R A

    2005-01-01

    We study the relationship between the energy and entropy of a black body photon gas, within an idealised spherical adiabatic enclosure of radius R, as this is compressed into a self-gravitating regime. We show that this regime approximately coincides with the black hole regime for the system, i.e., R ~ R_{s}, where R_{s} denotes the Schwarzschild radius of the system. The entropy of this system is always below the suggested Holographic bound, even as R \\to R_{s}. A plausible quantum configuration for the photon gas at R \\to R_{s} is suggested, which satisfies all energy, entropy and temperature black hole conditions. Finally we examine our results from the point of view of recent Loop Quantum Gravity ideas.

  15. Black Holes and Firewalls

    Science.gov (United States)

    Polchinski, Joseph

    2015-04-01

    Our modern understanding of space, time, matter, and even reality itself arose from the three great revolutions of the early twentieth century: special relativity, general relativity, and quantum mechanics. But a century later, this work is unfinished. Many deep connections have been discovered, but the full form of a unified theory incorporating all three principles is not known. Thought experiments and paradoxes have often played a key role in figuring out how to fit theories together. For the unification of general relativity and quantum mechanics, black holes have been an important arena. I will talk about the quantum mechanics of black holes, the information paradox, and the latest version of this paradox, the firewall. The firewall points to a conflict between our current theories of spacetime and of quantum mechanics. It may lead to a new understanding of how these are connected, perhaps based on quantum entanglement.

  16. 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.

  17. Noncommutative Solitonic Black Hole

    OpenAIRE

    Chang-Young, Ee; Kimm, Kyoungtae; Lee, Daeho; Lee, Youngone

    2011-01-01

    We investigate solitonic black hole solutions in three dimensional noncommutative spacetime. We do this in gravity with negative cosmological constant coupled to a scalar field. Noncommutativity is realized with the Moyal product which is expanded up to first order in the noncommutativity parameter in two spatial directions. With numerical simulation we study the effect of noncommutativity by increasing the value of the noncommutativity parameter starting from commutative solutions. We find t...

  18. Integrated urban drainage, status and perspectives

    DEFF Research Database (Denmark)

    Harremoës, Poul

    2002-01-01

    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...... 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...... 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...

  19. Hemobilia after percutaneous transhepatic biliary drainage

    International Nuclear Information System (INIS)

    Objective: To retrospectively analyze the occurance and management for patients with hemobilia after percutaneous transhepatic biliary drainage (PTBD). Methods: Consecutive 139 patients with inoperable obstructive jaundice were treated by PTBD. After taking percutaneous transhepatic cholangiography, procedure of puncturing the dilated biliary duct with metallic stent or plastic catheter placement was undertaken. Follow up was carded out with clinical, radiographic and laboratory evaluation. Procedure-and device-related complications were also recorded. Results: All patients went though PTBD successfully with total serum bilirnbin reducing from 360 μmol/l to 158.2 μmol/l, postoperatively. 43 cases received hemostatic. Transient hemobilia occurred in 11 cases, and severe hemobilia in other 5 cases requiring further management. Other 4 cases needed arterial embolization with another one failure. Conclusion: Hemobilia is a complication after PTBD, which can be promptly controlled with improving skillful maneuver. (authors)

  20. CANDU energy for steam assisted gravity drainage

    International Nuclear Information System (INIS)

    Traditional open-pit mining has been used by industry for many years to remove oil sands from shallow deposits. To increase production capacity, the industry is looking for new technology to exploit bitumen from deep deposits. Among them, SAGD (Steam-Assisted Gravity Drainage) appears to be the most promising approach. It uses steam to remove bitumen from underground reservoirs. Recently, the SAGD recovery process has been put into commercial operation by major oil companies.Atomic Energy Canada Limited has assessed the use of the ACR-1000 as a source of heat and electricity for oil sand extraction and processing. The ACR-1000 design is an evolutionary development of the familiar CANDU technology, adding innovations to enhance economics, operations, and safety margins. The net electrical output from a standard ACR-1000 will be close to 1100 MWe, depending on local cooling water temperature

  1. Protein separation by differential drainage from foam.

    Science.gov (United States)

    Mohan, S B; Lyddiatt, A

    1994-11-20

    Commercially available beer, which is a dilute solution containing components of yeast, malt, and hop used in the manufacture of the beer, was used as a model system to demonstrate the potential of foam fractionation beyond the primary foaming stage. Most of the components present in the beer concentrated in the initial foam, but they drained differentially in the subsequent collapsed foam collected over a period of 30 min. This resulted in further enrichment, in particular, of components which were present in low concentration in the original beer, Preferential drainage from foam, hence, might provide a novel way of fractionating further the proteins concentrated initially in the liquid films of foam. (c) 1994 John Wiley & Sons, Inc. PMID:18618553

  2. Foam drainage on a sloping weir

    Science.gov (United States)

    Grassia, P.; Neethling, S. J.; Cilliers, J. J.

    2002-08-01

    Foam drainage is considered in a froth flotation tank with a sloping weir. The drainage is shown to be gravity dominated in most of the foam, except for thin boundary layers at the base of the froth, and along the sloping weir. The mathematical reason for the boundary layers is that capillary suction is a much weaker effect than gravity, but cannot be ignored altogether, because it represents a singular perturbation. The relative weakness of capillary suction with respect to gravity is represented by a key dimensionless parameter, denoted K, which satisfies Kll 1. The volumetric flow at any point along the weir boundary layer is the accumulation of all liquid that has rained onto the weir above the point in question: typically, this flow is linear in distance measured downward from the weir lip. All liquid raining onto the weir is ultimately returned to the pulp phase as a high-speed jet. The jet velocity scales with the frac{2}{3} power of distance from the weir lip, and is O(K^{-2/3}) times larger than the typical velocity in the gravity-dominated flow in the bulk of the flotation tank. The liquid volume fraction in the jet is likewise O(K^{-2/3}) larger than that in the bulk. Across the jet, the foam exhibits a known profile of liquid fraction vs. distance from the weir: this is known as the equilibrium profile. The foam requires a distance equivalent to O(K^{4/3}) weir lengths to dry out significantly from the wetness value on the weir, but a larger O(K) distance to fall back to a wetness comparable with that in the bulk of the froth.

  3. Copper isotope fractionation in acid mine drainage

    Science.gov (United States)

    Kimball, B.E.; Mathur, R.; Dohnalkova, A.C.; Wall, A.J.; Runkel, R.L.; Brantley, S.L.

    2009-01-01

    We measured the Cu isotopic composition of primary minerals and stream water affected by acid mine drainage in a mineralized watershed (Colorado, USA). The ??65Cu values (based on 65Cu/63Cu) of enargite (??65Cu = -0.01 ?? 0.10???; 2??) and chalcopyrite (??65Cu = 0.16 ?? 0.10???) are within the range of reported values for terrestrial primary Cu sulfides (-1??? fractionation (??aq-min = ??65Cuaq - ??65Cumin, where the latter is measured on mineral samples from the field system), equals 1.43 ?? 0.14??? and 1.60 ?? 0.14??? for chalcopyrite and enargite, respectively. To interpret this field survey, we leached chalcopyrite and enargite in batch experiments and found that, as in the field, the leachate is enriched in 65Cu relative to chalcopyrite (1.37 ?? 0.14???) and enargite (0.98 ?? 0.14???) when microorganisms are absent. Leaching of minerals in the presence of Acidithiobacillus ferrooxidans results in smaller average fractionation in the opposite direction for chalcopyrite (??aq-mino = - 0.57 ?? 0.14 ???, where mino refers to the starting mineral) and no apparent fractionation for enargite (??aq-mino = 0.14 ?? 0.14 ???). Abiotic fractionation is attributed to preferential oxidation of 65Cu+ at the interface of the isotopically homogeneous mineral and the surface oxidized layer, followed by solubilization. When microorganisms are present, the abiotic fractionation is most likely not seen due to preferential association of 65Cuaq with A. ferrooxidans cells and related precipitates. In the biotic experiments, Cu was observed under TEM to occur in precipitates around bacteria and in intracellular polyphosphate granules. Thus, the values of ??65Cu in the field and laboratory systems are presumably determined by the balance of Cu released abiotically and Cu that interacts with cells and related precipitates. Such isotopic signatures resulting from Cu sulfide dissolution should be useful for acid mine drainage remediation and ore prospecting purposes. ?? 2008 Elsevier Ltd.

  4. 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...

  5. Thermal corpuscular black holes

    Science.gov (United States)

    Casadio, Roberto; Giugno, Andrea; Orlandi, Alessio

    2015-06-01

    We study the corpuscular model of an evaporating black hole consisting of a specific quantum state for a large number N of self-confined bosons. The single-particle spectrum contains a discrete ground state of energy m (corresponding to toy gravitons forming the black hole), and a gapless continuous spectrum (to accommodate for the Hawking radiation with energy ω >m ). Each constituent is in a superposition of the ground state and a Planckian distribution at the expected Hawking temperature in the continuum. We first find that, assuming the Hawking radiation is the leading effect of the internal scatterings, the corresponding 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 =N m and a Planckian distribution for E >M at the same Hawking temperature. From this collective state, we compute the partition function and obtain an entropy which reproduces the usual area law with a logarithmic correction precisely related with the Hawking component. By means of the horizon wave function for the system, we finally show the backreaction of modes with ω >m reduces the Hawking flux. Both corrections, to the entropy and to the Hawking flux, suggest the evaporation properly stops for vanishing mass, if the black hole is in this particular quantum state.

  6. 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...

  7. 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…

  8. 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...

  9. 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...

  10. 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...

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Agricultural Drainage Water Management in the Upper Mississippi River Basin: Potential Impact and Implementation Strategies

    Science.gov (United States)

    The unique soil and climate of the Upper Mississippi River Basin area provide the resources for bountiful agricultural production. Agricultural drainage (both surface and subsurface drainage) is essential for achieving economically viable crop production and management. Drainage practices alter the ...

  17. 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.

  18. Quasi-one-dimensional foam drainage

    Science.gov (United States)

    Grassia, P.; Cilliers, J. J.; Neethling, S. J.; Ventura-Medina, E.

    Foam drainage is considered in a froth flotation cell. Air flow through the foam is described by a simple two-dimensional deceleration flow, modelling the foam spilling over a weir. Foam microstructure is given in terms of the number of channels (Plateau borders) per unit area, which scales as the inverse square of bubble size. The Plateau border number density decreases with height in the foam, and also decreases horizontally as the weir is approached. Foam drainage equations, applicable in the dry foam limit, are described. These can be used to determine the average cross-sectional area of a Plateau border, denoted A, as a function of position in the foam. Quasi-one-dimensional solutions are available in which A only varies vertically, in spite of the two-dimensional nature of the air flow and Plateau border number density fields. For such situations the liquid drainage relative to the air flow is purely vertical. The parametric behaviour of the system is investigated with respect to a number of dimensionless parameters: K (the strength of capillary suction relative to gravity), α (the deceleration of the air flow), and n and h (respectively, the horizontal and vertical variations of the Plateau border number density). The parameter K is small, implying the existence of boundary layer solutions: capillary suction is negligible except in thin layers near the bottom boundary. The boundary layer thickness (when converted back to dimensional variables) is independent of the height of the foam. The deceleration parameter α affects the Plateau border area on the top boundary: weaker decelerations give larger Plateau border areas at the surface. For weak decelerations, there is rapid convergence of the boundary layer solutions at the bottom onto ones with negligible capillary suction higher up. For strong decelerations, two branches of solutions for A are possible in the K=0 limit: one is smooth, and the other has a distinct kink. The full system, with small but non

  19. 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.

  20. Hidden Structures of Black Holes

    CERN Document Server

    Vercnocke, Bert

    2010-01-01

    This thesis investigates two main topics concerning black holes in extensions of general relativity inspired by string theory. First, the structure of the equations of motion underlying black hole solutions is considered, in theories of D-dimensional gravity coupled to scalars and vectors. For solutions preserving supersymmetry, the equations of motion have a dramatic simplification: they become first-order instead of the second-order equations one would expect. Recently, it was found that this is a feature some non-supersymmetric black hole solutions exhibit as well. We investigate if this holds more generally, by examining what the conditions are to have first-order equations for the scalar fields of non-supersymmetric black holes, that mimic the form of their supersymmetric counterparts. This is illustrated in examples. Second, the structure of black holes themselves is investigated. String theory has been successful in explaining the Bekenstein-Hawking entropy for (mainly supersymmetric) black holes from ...

  1. Small black holes on cylinders

    International Nuclear Information System (INIS)

    We find the metric of small black holes on cylinders, i.e. neutral and static black holes with a small mass in d-dimensional Minkowski space times a circle. The metric is found using an ansatz for black holes on cylinders proposed in J. High Energy Phys. 05, 032 (2002). We use the new metric to compute corrections to the thermodynamics which is seen to deviate from that of the (d+1)-dimensional Schwarzschild black hole. Moreover, we compute the leading correction to the relative binding energy which is found to be non-zero. We discuss the consequences of these results for the general understanding of black holes and we connect the results to the phase structure of black holes and strings on cylinders

  2. Black Hole's 1/N Hair

    CERN Document Server

    Dvali, Gia

    2013-01-01

    According to the standard view classically black holes carry no hair, whereas quantum hair is at best exponentially weak. We show that suppression of hair is an artifact of the semi-classical treatment and that in the quantum picture hair appears as an inverse mass-square effect. Such hair is predicted in the microscopic quantum description in which a black hole represents a self-sustained leaky Bose-condensate of N soft gravitons. In this picture the Hawking radiation is the quantum depletion of the condensate. Within this picture we show that quantum black hole physics is fully compatible with continuous global symmetries and that global hair appears with the strength B/N, where B is the global charge swallowed by the black hole. For large charge this hair has dramatic effect on black hole dynamics. Our findings can have interesting astrophysical consequences, such as existence of black holes with large detectable baryonic and leptonic numbers.

  3. 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

  4. stu Black Holes Unveiled

    Directory of Open Access Journals (Sweden)

    Armen Yeranyan

    2008-10-01

    Full Text Available The general solutions of the radial attractor flow equations for extremal black holes, both for non-BPS with non-vanishing central charge Z and for Z = 0, are obtained for the so-called stu model, the minimal rank-3 N = 2 symmetric supergravity in d = 4 space-time dimensions. Comparisons with previous partial results, as well as the fake supergravity (first order formalism and an analysis of the marginal stability of corresponding D-brane configurations, are given.

  5. Noncommutative black holes

    Science.gov (United States)

    Bastos, C.; Bertolami, O.; Dias, N. C.; Prata, J. N.

    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, η. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.

  6. 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.

  7. Noncommutative black holes

    International Nuclear Information System (INIS)

    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, η. Furthermore, the t = r = 0 singularity is analysed in the noncommutative regime and it is shown that the wave function vanishes in this limit.

  8. 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.

  9. 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

  10. The Antarctic ozone hole

    International Nuclear Information System (INIS)

    Since the mid 1970s, the ozone layer over Antarctica has experienced massive destruction during every spring. In this article, we will consider the atmosphere, and what ozone and the ozone layer actually are. We explore the chemistry responsible for the ozone destruction, and learn about why conditions favour ozone destruction over Antarctica. For the historical perspective, the events leading up to the discovery of the 'hole' are presented, as well as the response from the international community and the measures taken to protect the ozone layer now and into the future

  11. Information Storage in Black Holes

    OpenAIRE

    Maia, M. D.

    2005-01-01

    The information loss paradox for Schwarzschild black holes is examined, using the ADS/CFT correspondence extended to the $M_6 (4,2)$ bulk. It is found that the only option compatible with the preservation of the quantum unitarity is when a regular remnant region of the black hole survives to the black hole evaporation process, where information can be stored and eventually retrieved.

  12. 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...

  13. Brane-world black holes

    International Nuclear Information System (INIS)

    In this talk, I present and discuss a number of attempts to construct black hole solutions in models with Warped Extra Dimensions. Then, a contact is made with models with Large Extra Dimensions, where black-hole solutions are easily constructed - here the focus will be on the properties of microscopic black holes and the possibility of using phenomena associated with them, such as the emission of Hawking radiation, to discover fundamental properties of our spacetime.

  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. 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.

  16. 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.

  17. A Simple Conceptual Model for Deep Drainage Under Surface Irrigation

    Science.gov (United States)

    Bethune, M. G.; Selle, B.

    2006-12-01

    Excess deep drainage causes rising water tables and soil salinity under irrigated agriculture. Understanding the soil and management factors influencing deep drainage is crucial for controlling salinity risk in irrigated areas. A lysimeter experiment in SE-Australia was conducted to quantify the deep drainage response to different soil types, watertable levels and ponding times during surface irrigation. We propose a simple conceptual model calculating deep drainage between two irrigation events as the product of the final infiltration rate of the soil and the period of ponding during irrigation: The final infiltration rate is the key soil parameter influencing deep drainage and the time of ponding captures the impact of management on deep drainage. The simple conceptual model is as powerful as a complex Artificial Neural Network with inputs typically required by a physically based model. This shows that the simple conceptual model extracts the relevant deep drainage patterns from the data. We demonstrate that the simple conceptual model is applicable at field scales and no model calibration is required.

  18. Artificial lymphatic drainage systems for vascularized microfluidic scaffolds.

    Science.gov (United States)

    Wong, Keith H K; Truslow, James G; Khankhel, Aimal H; Chan, Kelvin L S; Tien, Joe

    2013-08-01

    The formation of a stably perfused microvasculature continues to be a major challenge in tissue engineering. Previous work has suggested the importance of a sufficiently large transmural pressure in maintaining vascular stability and perfusion. Here we show that a system of empty channels that provides a drainage function analogous to that of lymphatic microvasculature in vivo can stabilize vascular adhesion and maintain perfusion rate in dense, hydraulically resistive fibrin scaffolds in vitro. In the absence of drainage, endothelial delamination increased as scaffold density increased from 6 to 30 mg/mL and scaffold hydraulic conductivity decreased by a factor of 20. Single drainage channels exerted only localized vascular stabilization, the extent of which depended on the distance between vessel and drainage as well as scaffold density. Computational modeling of these experiments yielded an estimate of 0.40-1.36 cm H2O for the minimum transmural pressure required for vascular stability. We further designed and constructed fibrin patches (0.8 × 0.9 cm(2)) that were perfused by a parallel array of vessels and drained by an orthogonal array of drainage channels; only with the drainage did the vessels display long-term stability and perfusion. This work underscores the importance of drainage in vascularization, especially when a dense, hydraulically resistive scaffold is used. PMID:23281125

  19. Black Holes in Higher Dimensions

    International Nuclear Information System (INIS)

    In four space-time dimensions black holes of Einstein-Maxwell theory satisfy a number of theorems. In more than four space-time dimensions, however, some of the properties of black holes can change. In particular, uniqueness of black holes no longer holds. In five and more dimensions black rings arise. Thus in a certain region of the phase diagram there are three black objects with the same global charges present. Here we discuss properties of higher-dimensional vacuum and charged black holes, which possess a spherical horizon topology, and of vacuum and charged black rings, which have a ringlike horizon topology

  20. 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.

  1. 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.

  2. Quantum black hole without singularity

    CERN Document Server

    Kiefer, Claus

    2015-01-01

    We discuss the quantization of a spherical dust shell in a rigorous manner. Classically, the shell can collapse to form a black hole with a singularity. In the quantum theory, we construct a well-defined self-adjoint extension for the Hamilton operator. As a result, the evolution is unitary and the singularity is avoided. If we represent the shell initially by a narrow wave packet, it will first contract until it reaches the region where classically a black hole would form, but then re-expands to infinity. In a way, the state can be interpreted as a superposition of a black hole with a white hole.

  3. Thermodynamics of Accelerating Black Holes

    CERN Document Server

    Appels, Michael; Kubiznak, David

    2016-01-01

    We address a long-standing problem of describing the thermodynamics of a charged 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.

  4. 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.

  5. Acceleration of black hole universe

    Science.gov (United States)

    Zhang, T. X.; Frederick, C.

    2014-01-01

    Recently, Zhang slightly modified the standard big bang theory and developed a new cosmological model called black hole universe, which is consistent with Mach's principle, governed by Einstein's general theory of relativity, and able to explain all observations of the universe. Previous studies accounted for the origin, structure, evolution, expansion, and cosmic microwave background radiation of the black hole universe, which grew from a star-like black hole with several solar masses through a supermassive black hole with billions of solar masses to the present state with hundred billion-trillions of solar masses by accreting ambient matter and merging with other black holes. This paper investigates acceleration of the black hole universe and provides an alternative explanation for the redshift and luminosity distance measurements of type Ia supernovae. The results indicate that the black hole universe accelerates its expansion when it accretes the ambient matter in an increasing rate. In other words, i.e., when the second-order derivative of the mass of the black hole universe with respect to the time is positive . For a constant deceleration parameter , we can perfectly explain the type Ia supernova measurements with the reduced chi-square to be very close to unity, χ red˜1.0012. The expansion and acceleration of black hole universe are driven by external energy.

  6. 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.

  7. Copper isotope fractionation in acid mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Kimball, Bryn E; Mathur, Ryan; Dohnalkova, Alice; Wall, A J; Runkel, R L; Brantley, Susan L

    2009-03-01

    We surveyed the Cu isotopic composition of primary minerals and stream water affected by acid mine drainage in a mineralized watershed located in southwestern Colorado, USA. The δ65Cu values (based on 65Cu/63Cu) of local enargite (δ65Cu = -0.01 ± 0.10‰; 2σ) and chalcopyrite (δ65Cu = 0.16 ± 0.10‰) are within the general range of previously reported values for terrestrial primary Cu sulfides (-1‰ < δ65Cu < 1). These mineral samples show lower δ65Cu values than stream waters (δ65Cu = 1.36 - 1.74 ± 0.10‰), with an average isotopic fractionation (quantified as Δaq-mino = δ65Cuaq – δ65Cu min, where Cuaq is leached Cu and Cu mino is the original mineral) of 1.60 ± 0.14‰ and 1.43 ± 0.14‰ for enargite and chalcopyrite, respectively.

  8. 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.

  9. 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.

  10. Superficial drainage studies in open-pit mines

    International Nuclear Information System (INIS)

    Drainage studies concerning large open-pit mining projects can be of vital importance throughout the mining activity itself as they may assist in avoiding activity interruptions due to drainage problems, therefore representing substantial savings. These studies should, in fact, be carried out from the initial activity stages and shall be considered in operational, project and planning decisions in order to optimize results and reduce costs. This specific study presents a drainage study systematization proposal, enphasazing economic decision criteria. The authors comment on studies of this nature developed at the Caldas uranium mine - NUCLEBRAS. (D.J.M.)

  11. Uncertainty Assessment in Long Term Urban Drainage Modelling

    DEFF Research Database (Denmark)

    Thorndahl, Søren

    The thesis covers a general introduction and a combilation of seven papers on the subject of uncertainty assessment in urban drainage modelling. Urban drainage models applied for design and analysis of urban drainage systems are uncertain due to uncertainty in parameter assessment and especially...... the probability of system failures (defined as either flooding or surcharge of manholes or combined sewer overflow); (2) an application of the Generalized Likelihood Uncertainty Estimation methodology in which an event based stochastic calibration is performed; and (3) long term Monte Carlo simulations...

  12. 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 ...

  13. 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...

  14. Quantum black hole evaporation

    CERN Document Server

    Schoutens, K; Verlinde, Erik; Schoutens, Kareljan; Verlinde, Erik; Verlinde, Herman

    1993-01-01

    We investigate a recently proposed model for a full quantum description of two-dimensional black hole evaporation, in which a reflecting boundary condition is imposed in the strong coupling region. It is shown that in this model each initial state is mapped to a well-defined asymptotic out-state, provided one performs a certain projection in the gravitational zero mode sector. We find that for an incoming localized energy pulse, the corresponding out-going state contains approximately thermal radiation, in accordance with semi-classical predictions. In addition, our model allows for certain acausal strong coupling effects near the singularity, that give rise to corrections to the Hawking spectrum and restore the coherence of the out-state. To an asymptotic observer these corrections appear to originate from behind the receding apparent horizon and start to influence the out-going state long before the black hole has emitted most of its mass. Finally, by putting the system in a finite box, we are able to deriv...

  15. Thermal BEC black holes

    CERN Document Server

    Casadio, Roberto; Micu, Octavian; Orlandi, Alessio

    2015-01-01

    We review some features of BEC models of black holes obtained by means of the HWF formalism. We consider the KG equation for a toy graviton field coupled to a static matter current in spherical symmetry. 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 continuous occupation number. An attractive self-interaction is needed for bound states to form, so 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 HWF 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), in agreement with semiclassical calculations and different from a single very massive particle. The spectrum contains a...

  16. Thermal corpuscular black holes

    CERN Document Server

    Casadio, Roberto; Orlandi, Alessio

    2015-01-01

    We study the corpuscular model of an evaporating black hole consisting of a specific quantum state for a large number $N$ of self-confined bosons. The single-particle spectrum contains a discrete ground state of energy $m$ (corresponding to toy gravitons forming the black hole), and a gapless continuous spectrum (to accommodate for the Hawking radiation with energy $\\omega>m$). Each constituent is in a superposition of the ground state and a Planckian distribution at the expected Hawking temperature in the continuum. We first find that, assuming the Hawking radiation is the leading effect of the internal scatterings, the corresponding $N$-particle state can be collectively described by a single-particle wave-function given by a superposition of a total ground state with energy $M=N\\,m$ and a Planckian distribution for $E>M$ at the same Hawking temperature. From this collective state, we compute the partition function and obtain an entropy which reproduces the usual area law with a logarithmic correction preci...

  17. Identification and Quantification of Flavonoids and Phenolic Acids in Burr Parsley (Caucalis platycarpos L., Using High-Performance Liquid Chromatography with Diode Array Detection and Electrospray Ionization Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Ana Mornar

    2009-07-01

    Full Text Available A sensitive method coupling high-performance liquid chromatography (HPLC with diode-array detector (DAD and electrospray ionization mass spectrometry (MS was optimized for the separation and identification of phenolic acids, flavonoid glycosides and flavonoid aglycones in the extract of burr parsley (Caucalis platycarpos L.. Fragmentation behavior of flavonoid glycosides and phenolic acids were investigated using ion trap mass spectrometry in negative electrospray ionization. The MS, MSn and UV data together with HPLC retention time (TR of phenolic acids and flavonoids allowed structural characterization of these compounds. Caffeoylquinic acid (CQA isomers, p-coumaroyl-quinic acids (p-CoQA, feruloylquinic acids (FQA, dicaffeoylquinic acids (diCQA, luteolin-7-O-rutinoside, apigenin-7-O-rutinoside as well as isolated chrysoeriol-7-O-rutinoside have been identified as constituents of C. platycarpos for the first time. An accurate, precise and sensitive LC-DAD method for quantification of four phenolic acids (3-O-caffeoylquinic, caffeic, p-coumaric, o-coumaric acid, four flavonoid glycosides (luteolin-7-O-glucoside, apigenin-7-O-glucoside, quercetin-3-O-galactoside, quercetin-3-O-rhamnoside, and three flavonoid aglycones (luteolin, apigenin, chrysoeriol in C. platycarpos extract was validated in terms of linearity, limit of detection, limit of quantification, precision and accuracy. 3-O-caffeoylquinic acid was the predominant phenolic acid and luteolin-7-O-glucoside was the predominant flavonoid glycoside.

  18. 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...

  19. 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....

  20. 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.

  1. 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...

  2. Hearing Outcomes after Surgical Drainage of Petrous Apex Cholesterol Granuloma

    OpenAIRE

    Rihani, Jordan; Kutz, J. Walter; Isaacson, Brandon

    2014-01-01

    Objective This study aims to assess the hearing outcomes of patients undergoing surgical management of petrous apex cholesterol granuloma and to discuss the role of otic capsule–sparing approaches in drainage of petrous apex cholesterol granulomas.

  3. 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...

  4. 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.

  5. 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...

  6. 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...

  7. What, no black hole evaporation

    International Nuclear Information System (INIS)

    Tipler has claimed that the inward flux of negative energy across the horizon which (according to the semi-classical approximation) accompanies the evaporation of a black hole would cause a solar mass black hole to evaporate in less than a second. It is shown that this claim is in error. (orig.)

  8. 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.

  9. 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.

  10. 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....

  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. METHOD FOR CLEAINING A HOLE

    NARCIS (Netherlands)

    Janssen, G.C.A.

    1997-01-01

    Abstract of WO 9749122 (A1) Method for making a conducting connection between two spaced metallic layers situated in a semiconductor substrate. After a hole, a so-called via, has been made by etching, tungsten or aluminium is introduced into the hole by conventional techniques, such as CVD or fo

  13. 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

  14. Lymphatic drainage and CTV in pancreatic carcinoma.

    Science.gov (United States)

    Morganti, Alessio G; Cellini, Numa; Mattiucci, Gian Carlo; Macchia, Gabriella; Smaniotto, Daniela; Luzi, Stefano; Balducci, Mario; Deodato, Francesco; Valentini, Vincenzo; Trodella, Lucio

    2003-01-01

    CTV definition in exclusive or adjuvant radiation therapy of pancreatic carcinoma is essentially based on the opinion of "expert" authors and on the knowledge of lymphatic pathways. The subject has been widely debated. Radiotherapy treatments of the entire upper abdomen (liver and pancreatic region), pancreas and lymph node stations, to volumes focused on macroscopic tumor only, have been proposed. Carcinoma of exocrine pancreas is characterized by the frequent, early appearance of metastasis via the lymphatic route. Most commonly involved lymph node stations include those of the celiac trunk, superior mesenteric, peripancreatic, lumboaortic lymph nodes, those of the hepatic portal (the latter in particular for pancreatic head tumors) and of the hilum of spleen (the latter in particular for pancreatic tail tumors). The possible multicentricity of pancreatic carcinoma, most likely due to intraductal spread, should lead to the inclusion in the CTV of the entire pancreatic parenchyma. This should be considered also for the frequent perineural intra- or extrapancreatic spread of pancreatic carcinoma present also in small tumors (T1). In extrapancreatic spread the retropancreatic adipose tissue should be included in the CTV at least at the GTV level. At the present state of knowledge, in the absence of pattern of failure analysis and of comparison of different treatment approaches, in terms of the definition of volumes of interest, CTV definitions which include lymphatic drainage stations, most part of pancreatic parenchyma and retropancreatic adipose tissue seem justified especially in treatments for cure. In palliation, the CTV may be limited to the GTV and the adipose tissue behind it. PMID:15018319

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

    OpenAIRE

    Ismail Ahmed; Derbalah Aly; Shaheen Sabry

    2015-01-01

    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 detect...

  16. Drainage systems, an occluded source of sanitation related outbreaks

    OpenAIRE

    Blom, Kristina

    2015-01-01

    Background Drainage systems and its role in sanitation related outbreaks are evident but still occluded once it has been installed. This current review evaluates if drainage systems can cause infections and thus be of clinical concern. Method A review of the literature was analyzed. Papers, guidelines, and quality management systems have been considered. Results Adequate sanitation is fundamental and a prerequisite for safe life and productivity. In contrast, malfunctioning sanitation has bee...

  17. 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...

  18. Unpredictability of lymphatic drainage patterns in melanoma patients.

    Science.gov (United States)

    Statius Muller, Markwin G; Hennipman, Feitse A; van Leeuwen, Paul A M; Pijpers, Rik; Vuylsteke, Ronald J; Meijer, Sybren

    2002-02-01

    We analysed the localisations of sentinel nodes (SN) found with the SN procedure to compare these sites with those that would have been predicted by conventional clinical descriptions of cutaneous lymphatic drainage. We assessed the surplus value of performing the SN procedure in melanoma patients who underwent regional nodal surgery. The SN procedure was performed in 348 patients with melanomas who were referred to our institute between 1993 and 1999. The localisations of the melanomas with the corresponding SNs were meticulously recorded on drawings of the human body and grouped according to the conventional descriptions. Predictability of lymph drainage was defined as the percentage of melanomas whose draining pattern was to the ipsilateral nearest basin, without simultaneous drainage to other basins or to an interval node. In all patients the SN procedure visualised at least one SN. We found 410 lymphatic basins in 347 patients. These basins included basins that could not have been predicted by the conventional clinical descriptions, such as multiple basins and contralateral drainage sites. For the head/neck region, SNs could be found in any of the basins described in the literature. The trunk's drainage predictability depended strongly on the melanoma localisation, ranging from 0% in the midline to 92% in one of the upper quadrants. The lower extremities had a high predictability of almost 100%, and predictability of drainage for the upper extremities ranged from 77% to 100%. In total, 34% of the patients had a cutaneous lymphatic drainage that was unpredictable, either totally or partially. We therefore conclude that an SN procedure is indispensable if the drainage site(s) are to be accurately identified. PMID:11930886

  19. 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.

  20. Prisons of Light - Black Holes

    Science.gov (United States)

    Ferguson, Kitty

    1998-05-01

    In this jargon-free review of one of the most fascinating topics in modern science, acclaimed science writer Kitty Ferguson examines the discovery of black holes, their nature, and what they can teach us about the mysteries of the universe. In search of the answers, we trace a star from its birth to its death throes, take a hypothetical journey to the border of a black hole and beyond, spend time with some of the world's leading theoretical physicists and astronomers, and take a whimsical look at some of the wild ideas black holes have inspired. Prisons of Light--Black Holes is comprehensive and detailed. Yet Kitty Ferguson's lightness of touch and down-to-earth analogies set this book apart from all others on black holes and make it a wonderfully stimulating and entertaining read.

  1. Wormholes as Black Hole Foils

    CERN Document Server

    Damour, Thibault

    2007-01-01

    We study to what extent wormholes can mimic the observational features of black holes. It is surprisingly found that many features that could be thought of as ``characteristic'' of a black hole (endowed with an event horizon) can be closely mimicked by a globally static wormhole, having no event horizon. This is the case for: the apparently irreversible accretion of matter down a hole, no-hair properties, quasi-normal-mode ringing, and even the dissipative properties of black hole horizons, such as a finite surface resistivity equal to 377 Ohms. The only way to distinguish the two geometries on an observationally reasonable time scale would be through the detection of Hawking's radiation, which is, however, too weak to be of practical relevance for astrophysical black holes. We point out the existence of an interesting spectrum of quantum microstates trapped in the throat of a wormhole which could be relevant for storing the information ``lost'' during a gravitational collapse.

  2. Black Hole Final State Conspiracies

    CERN Document Server

    McInnes, Brett

    2008-01-01

    The principle that unitarity must be preserved in all processes, no matter how exotic, has led to deep insights into boundary conditions in cosmology and black hole theory. In the case of black hole evaporation, Horowitz and Maldacena were led to propose that unitarity preservation can be understood in terms of a restriction imposed on the wave function at the singularity. Gottesman and Preskill showed that this natural idea only works if one postulates the presence of "conspiracies" between systems just inside the event horizon and states at much later times, near the singularity. We argue that some AdS black holes have unusual internal thermodynamics, and that this may permit the required "conspiracies" if real black holes are described by some kind of sum over all AdS black holes having the same entropy.

  3. 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...

  4. 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

  5. Area spectrum of slowly rotating black holes

    OpenAIRE

    Myung, Yun Soo

    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.

  6. Spacetime Duality of BTZ Black Hole

    OpenAIRE

    Ho, Jeongwon; Kim, Won T.; Park, Young-Jai

    1999-01-01

    We consider the duality of the quasilocal black hole thermodynamics, explicitly the quasilocal black hole thermodynamic first law, in BTZ black hole solution as a special one of the three-dimensional low energy effective string theory.

  7. 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.

  8. 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.

  9. Slicing black hole spacetimes

    CERN Document Server

    Bini, Donato; Geralico, Andrea; Jantzen, Robert T

    2015-01-01

    A general framework is developed to investigate the properties of useful choices of stationary spacelike slicings of stationary spacetimes whose congruences of timelike orthogonal trajectories are interpreted as the world lines of an associated family of observers, the kinematical properties of which in turn may be used to geometrically characterize the original slicings. On the other hand properties of the slicings themselves can directly characterize their utility motivated instead by other considerations like the initial value and evolution problems in the 3-plus-1 approach to general relativity. An attempt is made to categorize the various slicing conditions or "time gauges" used in the literature for the most familiar stationary spacetimes: black holes and their flat spacetime limit.

  10. 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. PMID:23982244

  11. 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%.

  12. Percutaneous transhepatic biliary drainage: analysis of 175 cases

    International Nuclear Information System (INIS)

    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

  13. Foam drainage in the presence of solid particles.

    Science.gov (United States)

    Wang, J; Nguyen, A V

    2016-03-28

    We conducted forced drainage experiments to study the liquid flow within the foams stabilized by a cationic surfactant (CTAB) in the presence of partially hydrophobic silica particles. The results show that the presence of solid particles, even when present in small amounts (0.0932 g L(-1) foam), can significantly decrease the foam permeability. The scaling behaviour (power law) between the drainage velocity and the imposed flow rate indicates that the presence of solid particles in the foams triggers a transition of the foam drainage regime from a node-dominated regime to a Plateau border-dominated regime. We applied two foam drainage equations for aqueous foams to simulate the experimental data and interpret the transition. The simulation results show that the presence of solid particles in the foams increases the rigidity of the interfaces and the viscous losses in the channels (the Plateau borders) of the foams, and decreases the foam permeability. We also generalize the theory for the effects of unattached hydrophilic particles on foam drainage by considering the effects of hydrophobicity and concentration of solid particles on the confinement of foam networks. This study explores liquid drainage in three-phase foams and is relevant to the field of hydrophobic particle separation by froth flotation, in which the wash water is commonly applied to the froth layer to improve the product grade. PMID:26877265

  14. Supersymmetric black holes in string theory

    OpenAIRE

    Mohaupt, T.

    2007-01-01

    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 to t...

  15. 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.

  16. 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.

  17. 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.)

  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. A nonsingular rotating black hole

    International Nuclear Information System (INIS)

    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.)

  20. Acceleration of Black Hole Universe

    Science.gov (United States)

    Zhang, Tianxi

    2012-05-01

    An alternative cosmological model called black hole universe has been recently proposed by the author. According to this model, the universe originated from a hot star-like black hole, and gradually grew up through a supermassive black hole to the present state by accreting ambient materials and merging with other black holes. The entire space is structured with an infinite number of layers hierarchically. The innermost three layers are the universe that we live, the outside space called mother universe, and the inside star-like and supermassive black holes called child universes. The outermost layer has an infinite radius and limits to zero for both the mass density and absolute temperature. All layers or universes are governed by the same physics, the Einstein general theory of relativity with the Robertson-Walker metric of space-time, and tend to expand outward physically. The evolution of the space structure is iterative. When one universe expands out, a new similar universe grows up from its inside. In this study. we will analyze the acceleration of black hole universe that accretes its ambient matter in an increasing rate. We will also compare the result obtained from the black hole universe model with the measurement of type Ia supernova and the result from the big bang cosmology.

  1. Quantum mechanics of black holes.

    Science.gov (United States)

    Witten, Edward

    2012-08-01

    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.

  2. Thermodynamics of Lifshitz black holes

    Science.gov (United States)

    Devecioǧlu, Deniz Olgu; Sarıoǧlu, Özgür

    2011-06-01

    We apply the recently extended conserved Killing charge definition of Abbott-Deser-Tekin formalism to compute, for the first time, the energies of analytic Lifshitz black holes in higher dimensions. We then calculate the temperature and the entropy of this large family of solutions, and study and discuss the first law of black hole thermodynamics. Along the way we also identify the possible critical points of the relevant quadratic curvature gravity theories. Separately, we also apply the generalized Killing charge definition to compute the energy and the angular momentum of the warped AdS3 black hole solution of the three-dimensional new massive gravity theory.

  3. Black holes and Higgs stability

    CERN Document Server

    Tetradis, Nikolaos

    2016-01-01

    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.

  4. 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 $H_3$.

  5. 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. PMID:25768747

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Hole history core hole DC-2 Hanford, Washington

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    The purpose of core hole DC-2 was to core drill vertically through the basalt and interbed units for stratigraphic depth determination and core collection and to provide a borehole for hydrological testing. The total depth of core hole DC-2 was 3,300 feet. Core recovery exceeded 99 percent of the total footage cores. The coring record is tabulated. 3 figures, 3 tables. (RWR)

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

    DEFF Research Database (Denmark)

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

    filters and constructed wetlands (CWs). Various natural and industrial P filter substrates (granulated Fe-oxides, crushed seashells, Filtralite-PTM, granulated lime, calcined diatomitic earth) have been tested for their affinity and long-term capacity to reduce inlet P concentrations to below...... environmental threshold values (long-term P-loading the sensitivity of flow-rate on P retention increased and further indicated......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...

  12. 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

  13. 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...

  14. 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.

  15. 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.

  16. '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.

  17. 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)

  18. Black hole accretion disc impacts

    Science.gov (United States)

    Pihajoki, P.

    2016-04-01

    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 λ = 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.

  19. 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.

  20. Black hole evaporation: a paradigm

    International Nuclear Information System (INIS)

    A paradigm describing black hole evaporation in non-perturbative quantum gravity is developed by combining two sets of detailed results: (i) resolution of the Schwarzschild singularity using quantum geometry methods and (ii) time evolution of black holes in the trapping and dynamical horizon frameworks. Quantum geometry effects introduce a major modification in the traditional spacetime diagram of black hole evaporation, providing a possible mechanism for recovery of information that is classically lost in the process of black hole formation. The paradigm is developed directly in the Lorentzian regime and necessary conditions for its viability are discussed. If these conditions are met, much of the tension between expectations based on spacetime geometry and structure of quantum theory would be resolved

  1. Switching off black hole evaporation

    International Nuclear Information System (INIS)

    The inclusion of the back-reaction in the Hawking effect leads to the result that, if vector boson fields predominate in nature, then black holes stop evaporating when their mass reaches a non-vanishing limiting value. (author)

  2. 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.

  3. 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.

  4. 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.

  5. Right Gastric Venous Drainage: Angiographic Analysis in 100 Patients

    Energy Technology Data Exchange (ETDEWEB)

    Seong, Nak Jong [Seoul National University Bundang Hospital, Sungnam (Korea, Republic of); Chung, Jin Wook; Kim, Hyo Cheol; Park, Jae Hyung; Jae, Hwan Jun [Seoul National University Hospital, Seoul (Korea, Republic of); An, Sang Bu [National Cancer Center, Ilsan (Korea, Republic of); Cho, Baik Hwan [Chonbuk National University Hospital, Chonju (Korea, Republic of)

    2012-01-15

    To evaluate the pattern of right gastric venous drainage by use of digital subtraction angiography. A series of 100 consecutive patients who underwent right gastric arteriography during transcatheter arterial chemoembolization for hepatocellular carcinoma were included in this study. Angiographic findings were retrospectively analyzed with respect to the presence or absence of the right and aberrant gastric veins, multiplicity of draining veins, aberrant right gastric venous drainage sites, and the termination pattern of aberrant right gastric veins (ARGVs). We also compared the relative size of the right and left gastric veins. A total of 49 patients collectively had 66 ARGVs. The common drainage sites for the ARGVs included the hepatic segment IV (n = 35) and segment I (n = 15). The termination pattern of ARGV could be classified into 4 different types. The most common type was termination as a superficial parenchymal blush formation in small areas without demonstrable portal branches. A statistically significant difference was found for the dominance of the right gastric vein in gastric venous drainage between the two groups with or without ARGV (p < 0.05, Fisher's exact test). In the group of patients without ARGV (n = 51), the right gastric vein was equal to (n = 9) or larger than (n = 17) the left gastric vein in 26 patients (26 of 51, 51%). The incidence of ARGV is higher than expected with four distinct types in its termination pattern. The right gastric vein may play a dominant role in gastric venous drainage.

  6. 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.

  7. 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. PMID:27048219

  8. Adequate drainage system design for heap leaching structures.

    Science.gov (United States)

    Majdi, Abbas; Amini, Mehdi; Nasab, Saeed Karimi

    2007-08-17

    The paper describes an optimum design of a drainage system for a heap leaching structure which has positive impacts on both mine environment and mine economics. In order to properly design a drainage system the causes of an increase in the acid level of the heap which in turn produces severe problems in the hydrometallurgy processes must be evaluated. One of the most significant negative impacts induced by an increase in the acid level within a heap structure is the increase of pore acid pressure which in turn increases the potential of a heap-slide that may endanger the mine environment. In this paper, initially the thickness of gravelly drainage layer is determined via existing empirical equations. Then by assuming that the calculated thickness is constant throughout the heap structure, an approach has been proposed to calculate the required internal diameter of the slotted polyethylene pipes which are used for auxiliary drainage purposes. In order to adequately design this diameter, the pipe's cross-sectional deformation due to stepped heap structure overburden pressure is taken into account. Finally, a design of an adequate drainage system for the heap structure 2 at Sarcheshmeh copper mine is presented and the results are compared with those calculated by exiting equations. PMID:17321044

  9. Observing a catastrophic thermokarst lake drainage in northern Alaska

    Science.gov (United States)

    Jones, Benjamin M.; Arp, Christopher D.

    2015-01-01

    The formation and drainage of thermokarst lakes have reshaped ice-rich permafrost lowlands in the Arctic throughout the Holocene. North of Teshekpuk Lake, on the Arctic Coastal Plain of northern Alaska, thermokarst lakes presently occupy 22.5% of the landscape, and drained thermokarst lake basins occupy 61.8%. Analysis of remotely sensed imagery indicates that nine lakes (>10 ha) have drained in the 1,750 km2 study area between 1955 and 2014. The most recent lake drainage was observed using in situ data loggers providing information on the duration and magnitude of the event, and a nearby weather station provided information on the environmental conditions preceding the lake drainage. Lake 195 (L195), an 80 ha thermokarst lake with an estimated water volume of ~872,000 m3, catastrophically drained on 05 July 2014. Abundant winter snowfall and heavy early summer precipitation resulted in elevated lake water levels that likely promoted bank overtopping, thermo-erosion along an ice-wedge network, and formation of a 9 m wide, 2 m deep, and 70 m long drainage gully. The lake emptied in 36 hours, with 75% of the water volume loss occurring in the first ten hours. The observed peak discharge of the resultant flood was 25 m3/s, which is similar to that in northern Alaska river basins whose areas are more than two orders of magnitude larger. Our findings support the catastrophic nature of sudden lake drainage events and the mechanistic hypotheses developed by J. Ross Mackay.

  10. 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].)

  11. 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.

  12. 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

  13. Model for Plateau border drainage of power-law fluid with mobile interface and its application to foam drainage.

    Science.gov (United States)

    Wang, Zebin; Narsimhan, Ganesan

    2006-08-01

    A model for drainage of a power-law fluid through a Plateau border is proposed which accounts for the actual Plateau border geometry and interfacial mobility. The non-dimensionalized Navier-Stokes equations have been solved using finite element method to obtain the contours of velocity within the Plateau border cross section and average Plateau border velocity in terms of dimensionless inverse surface viscosity and power-law rheological parameters. The velocity coefficient, the correction for the average velocity through a Plateau border of actual geometry compared to that for a simplified circular geometry of the same area of cross section, was expressed as a function of dimensionless inverse surface viscosity and flow behavior index of the power-law fluid. The results of this improved model for Plateau border drainage were then incorporated in a previously developed foam drainage model [G. Narsimhan, J. Food Eng. 14 (1991) 139] to predict the evolution of liquid holdup profiles in a standing foam. Foam drainage was found to be slower for actual Plateau border cross section compared to circular geometry and faster for higher interfacial mobility and larger bubble size. Evolution of liquid holdup profiles in a standing foam formed by whipping and stabilized by 0.1% beta-lactoglobulin in the presence of xanthan gum when subjected to 16g and 45g centrifugal force fields was measured using magnetic resonance imaging for different xanthan gum concentrations. Drainage resulted in the formation of a separate liquid layer at the bottom at longer times. Measured bubble size, surface shear viscosity of beta-lactoglobulin solutions and literature values of power-law parameters of xanthan gum solution were employed in the current model to predict the evolution of liquid holdup profile which compared well with the experimental data. Newtonian model for foam drainage for zero shear viscosity underpredicted drainage rates and did not agree with the experimental data. PMID

  14. Vacuum metastability with black holes.

    OpenAIRE

    Burda, Philipp; Gregory, Ruth; Moss, Ian

    2015-01-01

    We consider the possibility that small black holes can act as nucleation seeds for the decay of a metastable vacuum, focussing particularly on the Higgs potential. Using a thin-wall bubble approximation for the nucleation process, which is possible when generic quantum gravity corrections are added to the Higgs potential, we show that primordial black holes can stimulate vacuum decay. We demonstrate that for suitable parameter ranges, the vacuum decay process dominates over the Hawking evapor...

  15. Energy Extraction from Black Holes

    OpenAIRE

    Straumann, Norbert

    2007-01-01

    In this lecture I give an introduction to the rotational energy extraction of black holes by the electromagnetic Blandford-Znajek process and the generation of relativistic jets. After some basic material on the electrodynamics of black hole magnetospheres, we derive the most important results of Blandford and Znajek by making use of Kerr-Schild coordinates, which are regular on the horizon. In a final part we briefly describe results of recent numerical simulations of accretion flows on rota...

  16. Dynamic black-hole entropy

    OpenAIRE

    Hayward, Sean A.; Mukohyama, Shinji; Ashworth, M. C.

    1998-01-01

    We consider two non-statistical definitions of entropy for dynamic (non-stationary) black holes in spherical symmetry. The first is analogous to the original Clausius definition of thermodynamic entropy: there is a first law containing an energy-supply term which equals surface gravity times a total differential. The second is Wald's Noether-charge method, adapted to dynamic black holes by using the Kodama flow. Both definitions give the same answer for Einstein gravity: one-quarter the area ...

  17. Black Holes and String Theory

    CERN Document Server

    Myers, R C

    2001-01-01

    This is a short summary of my lectures given at the Fourth Mexican School on Gravitation and Mathematical Physics. These lectures gave a brief introduction to black holes in string theory, in which I primarily focussed on describing some of the recent calculations of black hole entropy using the statistical mechanics of D-brane states. The following overview will also provide the interested students with an introduction to the relevant literature.

  18. Charged rotating noncommutative black holes

    International Nuclear Information System (INIS)

    In this paper we complete the program of the noncomutative geometry inspired black holes, providing the richest possible solution, endowed with mass, charge and angular momentum. After providing a prescription for employing the Newman-Janis algorithm in the case of nonvanishing stress tensors, we find regular axisymmetric charged black holes in the presence of a minimal length. We study also the new thermodynamics and we determine the corresponding higher-dimensional solutions. As a conclusion we make some consideration about possible applications.

  19. Charged rotating noncommutative black holes

    Science.gov (United States)

    Modesto, Leonardo; Nicolini, Piero

    2010-11-01

    In this paper we complete the program of the noncomutative geometry inspired black holes, providing the richest possible solution, endowed with mass, charge and angular momentum. After providing a prescription for employing the Newman-Janis algorithm in the case of nonvanishing stress tensors, we find regular axisymmetric charged black holes in the presence of a minimal length. We study also the new thermodynamics and we determine the corresponding higher-dimensional solutions. As a conclusion we make some consideration about possible applications.

  20. Charged rotating noncommutative black holes

    CERN Document Server

    Modesto, Leonardo

    2010-01-01

    In this paper we complete the program of the Noncomutative Geometry inspired black holes, providing the richest possible solution, endowed with mass, charge and angular momentum. After providing a prescription for employing the Newmann-Janis algorithm in case of nonvanishing stress tensors, we find regular axisymmetric charged black holes in the presence of a minimal length. We study also the new thermodynamics and we determine the corresponding higher-dimensional solutions. As a conclusion we make some consideration about possible applications.

  1. 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.

  2. 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.

  3. Accretion, Primordial Black Holes and Standard Cosmology

    OpenAIRE

    Nayak, Bibekananda; Singh, Lambodar Prasad

    2009-01-01

    Primordial Black Holes evaporate due to Hawking radiation. We find that the evaporation time of primordial black holes increase when accretion of radiation is included.Thus depending on accretion efficiency more and more number of primordial black holes are existing today, which strengthens the idea that the primordial black holes are the proper candidate for dark matter.

  4. 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.

  5. Black Hole Complementary Principle and Noncommutative Membrane

    International Nuclear Information System (INIS)

    In the spirit of black hole complementary principle, we have found the noncommutative membrane of Scharzchild black holes. In this paper we extend our results to Kerr black hole and see the same story. Also we make a conjecture that spacetimes are noncommutative on the stretched membrane of the more general Kerr-Newman black hole.

  6. Towards a Theory of Quantum Black Hole

    OpenAIRE

    Berezin, V.

    2001-01-01

    We describe some specific quantum black hole model. It is pointed out that the origin of a black hole entropy is the very process of quantum gravitational collapse. The quantum black hole mass spectrum is extracted from the mass spectrum of the gravitating source. The classical analog of quantum black hole is constructed.

  7. 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.

  8. Thermodynamics of Horava-Lifshitz black holes

    Energy Technology Data Exchange (ETDEWEB)

    Myung, Yun Soo; Kim, Yong-Wan [Inje University, Institute of Basic Science and School of Computer Aided Science, Gimhae (Korea)

    2010-07-15

    We study black holes in the Horava-Lifshitz gravity with a parameter {lambda}. For 1/3{<=}{lambda}<3, the black holes behave the Lifshitz black holes with dynamical exponent 03, the black holes behave the Reissner-Nordstroem type black hole in asymptotically flat spacetimes. Hence, these all are quite different from the Schwarzschild-AdS black hole of Einstein gravity. The temperature, mass, entropy, and heat capacity are derived for investigating thermodynamic properties of these black holes. (orig.)

  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. Black hole quantum spectrum

    International Nuclear Information System (INIS)

    Introducing a black hole (BH) effective temperature, which takes into account both the non-strictly thermal character of Hawking radiation and the countable behavior of emissions of subsequent Hawking quanta, we recently re-analysed BH quasi-normal modes (QNMs) and interpreted them naturally in terms of quantum levels. In this work we improve such an analysis removing some approximations that have been implicitly used in our previous works and obtaining the corrected expressions for the formulas of the horizon's area quantization and the number of quanta of area and hence also for Bekenstein-Hawking entropy, its subleading corrections and the number of micro-states, i.e. quantities which are fundamental to realize the underlying quantum gravity theory, like functions of the QNMs quantum ''overtone'' number n and, in turn, of the BH quantum excited level. An approximation concerning the maximum value of n is also corrected. On the other hand, our previous results were strictly corrected only for scalar and gravitational perturbations. Here we show that the discussion holds also for vector perturbations. The analysis is totally consistent with the general conviction that BHs result in highly excited states representing both the ''hydrogen atom'' and the ''quasi-thermal emission'' in quantum gravity. Our BH model is somewhat similar to the semi-classical Bohr's model of the structure of a hydrogen atom. The thermal approximation of previous results in the literature is consistent with the results in this paper. In principle, such results could also have important implications for the BH information paradox. (orig.)

  11. Black hole quantum spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Corda, Christian [Institute for Theoretical Physics and Advanced Mathematics (IFM) Einstein-Galilei, Prato (Italy); Istituto Universitario di Ricerca ' ' Santa Rita' ' , Prato (Italy); International Institute for Applicable Mathematics and Information Sciences (IIAMIS), Hyderabad (India)

    2013-12-15

    Introducing a black hole (BH) effective temperature, which takes into account both the non-strictly thermal character of Hawking radiation and the countable behavior of emissions of subsequent Hawking quanta, we recently re-analysed BH quasi-normal modes (QNMs) and interpreted them naturally in terms of quantum levels. In this work we improve such an analysis removing some approximations that have been implicitly used in our previous works and obtaining the corrected expressions for the formulas of the horizon's area quantization and the number of quanta of area and hence also for Bekenstein-Hawking entropy, its subleading corrections and the number of micro-states, i.e. quantities which are fundamental to realize the underlying quantum gravity theory, like functions of the QNMs quantum ''overtone'' number n and, in turn, of the BH quantum excited level. An approximation concerning the maximum value of n is also corrected. On the other hand, our previous results were strictly corrected only for scalar and gravitational perturbations. Here we show that the discussion holds also for vector perturbations. The analysis is totally consistent with the general conviction that BHs result in highly excited states representing both the ''hydrogen atom'' and the ''quasi-thermal emission'' in quantum gravity. Our BH model is somewhat similar to the semi-classical Bohr's model of the structure of a hydrogen atom. The thermal approximation of previous results in the literature is consistent with the results in this paper. In principle, such results could also have important implications for the BH information paradox. (orig.)

  12. 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 (

  13. Drainage Network Design of Korean LILW Underground Repository

    International Nuclear Information System (INIS)

    The underground waste repository site is located at Gyeongju and is selected for the disposal of all the Low and Intermediate Level Radioactive Waste (LILW). Its operation is scheduled in the beginning of 2009. The repository, with a disposal capacity of 800,000 drums, will be constructed in granite bedrock near the seashore at the Gyeongju site. In the first phase of construction, the repository will have a capacity to dispose of 100,000 drums. Considering the depth of access tunnels and silos and high groundwater level, the drain type is applied for the underground repository. The drainage network is required to drain out the groundwater inflow of the underground repository during the operation. The drainage network is designed considering the arrangement of repository, radioactive zone, groundwater inflow, and service water, etc. After the closure, the operation of drainage network will be stopped

  14. 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.

  15. 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...

  16. 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.

  17. Estimate of drainage water behaviour in shallow lakes

    CERN Document Server

    El-Jaick, L J; El-Jaick, Lea J.

    2004-01-01

    A theoretical estimate of the explicit time dependence of a drainage water of shallow lakes is presented as an important contribution for understanding the lake dynamics. This information can be obtained from a sum of functions, largely used in fitting of experimental data. These functions were chosen because their centre and weight yield a good description of the water basin behaviour. The coefficients of these functions are here extracted using results of measured and / or calculated data for the state variables describing the shallow West Lake, Hangzou. This procedure can also be applied to other shallow lakes, generating geological information about their drainage basin, which is one of the most important parameters to describe their micrometeorological behaviour. One concludes this work emphasizing the relevance of the explicit time dependence of the drainage variables and the requirement of measured data to validate this approach.

  18. Massive Black Holes: formation and evolution

    OpenAIRE

    Rees, Martin J.; Volonteri, Marta

    2007-01-01

    Supermassive black holes are nowadays believed to reside in most local galaxies. Observations have revealed us vast information on the population of local and distant black holes, but the detailed physical properties of these dark massive objects are still to be proven. Accretion of gas and black hole mergers play a fundamental role in determining the two parameters defining a black hole: mass and spin. We briefly review here the basic properties of the population of supermassive black holes,...

  19. 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.

  20. Regular black hole in three dimensions

    International Nuclear Information System (INIS)

    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 the thermodynamics of this black hole with that of a non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy. (orig.)

  1. Regular black hole in three dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Myung, Yun Soo [Inje University, Institute of Basic Science and School of Computer Aided Science, Gimhae (Korea); Yoon, Myungseok [Sogang University, Center for Quantum Spacetime, Seoul (Korea)

    2009-07-15

    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 the thermodynamics of this black hole with that of a non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy. (orig.)

  2. Observational features of equatorial coronal hole jets

    OpenAIRE

    Nisticò, G.; V. Bothmer; S. Patsourakos; Zimbardo, G.

    2010-01-01

    Collimated ejections of plasma called "coronal hole jets" are commonly observed in polar coronal holes. However, such coronal jets are not only a specific features of polar coronal holes but they can also be found in coronal holes appearing at lower heliographic latitudes. In this paper we present some observations of "equatorial coronal hole jets" made up with data provided by the STEREO/SECCHI instruments during a period comprising March 2007 and December 2007. The jet e...

  3. Holes Cannot Be Counted As Immaterial Objects

    OpenAIRE

    Dr Phillip John Meadows

    2014-01-01

    In this paper I argue that the theory that holes are immaterial objects faces an objection that has traditionally been thought to be the principal difficulty with its main rival, which construes holes as material parts of material objects. Consequently, one of the principal advantages of identifying holes with immaterial objects is illusory: its apparent ease of accounting for truths about number of holes. I argue that in spite of this we should not think of holes as material p...

  4. Limiting drainage criterion for groundwater of mountain tunnel

    Institute of Scientific and Technical Information of China (English)

    程盼; 赵炼恒; 李亮; 邹金锋; 罗伟

    2014-01-01

    Large amount of groundwater discharging from tunnel is likely to cause destruction of the ecological environment in the vicinity of the tunnel, thus an appropriate drainage criterion should be established to balance the tunnel construction and groundwater. To assess the related problems, an limiting drainage standard ranging from 0.5 to 2.0 m3/(m·d) was suggested for mountain tunnels based on survey and comparative analysis. After that, for the purpose of verifying the rationality of the standard, a calculated formula for dewatering funnel volume caused by drainage was deduced on the basis of the groundwater dynamics and experience method. Furthermore, the equation about the relationship between water discharge and drawdown of groundwater table was presented. The permeability coefficient, specific yield and groundwater table value were introduced, and then combined with the above equation, the drawdown of groundwater table under the proposed limiting drainage criterion was calculated. It is shown that the proposed drainage standard can reach the purpose of protecting ecological environment under the following two conditions. One is the permeability coefficient ranges from 10−4 to 10−5 m/s and the specific yield ranges from 0.1 to 0.001. The other is the permeability coefficient varies from 10−6 to 10−8 m/s and the specific yield varies from 0.1 to 0.01. In addition, a majority of common geotechnical layers are involved in the above ranges. Thus, the proposed limiting drainage standard which ranges from 0.5 to 2.0 m3/(m·d) for mountain tunnel is reasonable.

  5. Nocturnal drainage wind characteristics in two converging air sheds

    International Nuclear Information System (INIS)

    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 250C during summer and about 200C 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-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

  6. Exocrine drainage in vascularized pancreas transplantation in the new millennium

    Science.gov (United States)

    El-Hennawy, Hany; Stratta, Robert J; Smith, Fowler

    2016-01-01

    The history of vascularized pancreas transplantation largely parallels developments in immunosuppression and technical refinements in transplant surgery. From the late-1980s to 1995, most pancreas transplants were whole organ pancreatic grafts with insulin delivery to the iliac vein and diversion of the pancreatic ductal secretions to the urinary bladder (systemic-bladder technique). The advent of bladder drainage revolutionized the safety and improved the success of pancreas transplantation. However, starting in 1995, a seismic change occurred from bladder to bowel exocrine drainage coincident with improvements in immunosuppression, preservation techniques, diagnostic monitoring, general medical care, and the success and frequency of enteric conversion. In the new millennium, pancreas transplants are performed predominantly as pancreatico-duodenal grafts with enteric diversion of the pancreatic ductal secretions coupled with iliac vein provision of insulin (systemic-enteric technique) although the systemic-bladder technique endures as a preferred alternative in selected cases. In the early 1990s, a novel technique of venous drainage into the superior mesenteric vein combined with bowel exocrine diversion (portal-enteric technique) was designed and subsequently refined over the next ≥ 20 years to re-create the natural physiology of the pancreas with first-pass hepatic processing of insulin. Enteric drainage usually refers to jejunal or ileal diversion of the exocrine secretions either with a primary enteric anastomosis or with an additional Roux limb. The portal-enteric technique has spawned a number of newer and revisited techniques of enteric exocrine drainage including duodenal or gastric diversion. Reports in the literature suggest no differences in pancreas transplant outcomes irrespective of type of either venous or exocrine diversion. The purpose of this review is to examine the literature on exocrine drainage in the new millennium (the purported

  7. Drainage vent systems: investigation and analysis of air pressure regime

    Energy Technology Data Exchange (ETDEWEB)

    Swaffield, J.A.; Jack, L.B. [Heriot-Watt University, Edinburgh (United Kingdom). Dept. of Building Engineering and Surveying

    1998-12-31

    Knowledge of the performance of building drainage vent systems and associated appliance trap seal loss and retention has developed in recent years due to extensive research into the generation and propagation of air pressure transients within drainage networks. This paper demonstrates how data gathered from experimental testing of several single stack systems, considering the influence of a wide range of parameters including stack diameter, roughness, height and applied water flow rate, can be used to provide generally applicable mathematical expressions which assist in determining the pressure regime present at critical points within such systems. (author)

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

    Institute of Scientific and Technical Information of China (English)

    Jin Wang; Kefu Chen; Fushan Chen; Chuanshan Zhao; Rendang Yang

    2004-01-01

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

  9. Gas drainage from different mine areas:optimal placement of drainage systems for deep coal seams with high gas emissions

    Institute of Scientific and Technical Information of China (English)

    Ping Lu; Ping Li; Jian Chen; Chuijin Zhang; Junhua Xue; Tao Yu

    2015-01-01

    The techniques of stress relief mining in low-permeability coal seams and pillarless gob side retained roadway entry using Y-type ventilation and gas drainage systems were developed to control gas outbursts and applied successfully. However, as the mining depth increasing, parts of the gas drainage system are not suitable for mines with high gas emissions. Because larger mining depths cause higher ground stresses, it becomes extremely difficult to maintain long gob side roadways. The greater deformation suffered by the roadway is not favorable for borehole drilling for continuous gas drainage. To solve these problems, Y-type ventilation and gas drainage systems installed from a roof roadway were designed for drainage optimization. This system was designed based on a gas-enrichment zone analysis developed from mining the 11-2 coal seam in the Zhuji Mine at Huainan, Anhui Province, China. The method of Y-type gas extraction from different mine areas was applied to the panel 1112(1) in the Zhuji Mine. The absolute gas emission rate was up to 116.3 m3/min with an average flow of 69.1 m3/min at an average drainage concentration of nearly 85%. After the Y-type method was adopted, the concentration of gas in the return air was 0.15%–0.64%, averaging 0.39%with a ventilation rate of 2100–2750 m3/min. The gas management system proved to be efficient, and the effective gas control allowed safe production to continue.

  10. 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.

  11. 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, ...

  12. Wormholes as black hole foils

    Science.gov (United States)

    Damour, Thibault; Solodukhin, Sergey N.

    2007-07-01

    We study to what extent wormholes can mimic the observational features of black holes. It is surprisingly found that many features that could be thought of as “characteristic” of a black hole (endowed with an event horizon) can be closely mimicked by a globally static wormhole, having no event horizon. This is the case for the apparently irreversible accretion of matter down a hole, no-hair properties, quasi-normal-mode ringing, and even the dissipative properties of black hole horizons, such as a finite surface resistivity equal to 377 Ohms. The only way to distinguish the two geometries on an observationally reasonable time scale would be through the detection of Hawking’s radiation, which is, however, too weak to be of practical relevance for astrophysical black holes. We point out the existence of an interesting spectrum of quantum microstates trapped in the throat of a wormhole which could be relevant for storing the information lost during a gravitational collapse.

  13. 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...

  14. Macroscopic black holes, microscopic black holes and noncommutative membrane

    Energy Technology Data Exchange (ETDEWEB)

    Li Miao [Institute of Theoretical Physics, Academia Sinica, PO Box 2735, Beijing 100080 (China)

    2004-07-21

    We study the stretched membrane of a black hole as consisting of a perfect fluid. We find that the pressure of this fluid is negative and the specific heat is also negative. A surprising result is that if we are to assume the fluid to be composed of some quanta, then the dispersion relation of the fundamental quantum is E = m{sup 2}/k, with m at the scale of the Planck mass. There are two possible interpretations of this dispersion relation. One is the noncommutative spacetime on the stretched membrane and the other is that the fundamental quanta are microscopic black holes.

  15. Macroscopic black holes, microscopic black holes and noncommutative membrane

    International Nuclear Information System (INIS)

    We study the stretched membrane of a black hole as consisting of a perfect fluid. We find that the pressure of this fluid is negative and the specific heat is also negative. A surprising result is that if we are to assume the fluid to be composed of some quanta, then the dispersion relation of the fundamental quantum is E = m2/k, with m at the scale of the Planck mass. There are two possible interpretations of this dispersion relation. One is the noncommutative spacetime on the stretched membrane and the other is that the fundamental quanta are microscopic black holes

  16. Numerical Simutation of the Gas Drainage Technology of Progressive and Large Diameter Buried Drainage Pipe%大直径穿层递进埋管抽采技术数值模拟

    Institute of Scientific and Technical Information of China (English)

    赵帅

    2011-01-01

    上保护层开采后,随着顶底板岩层移动、冒落,在顶底板一定范围内邻近层与保护层之间的煤岩层中形成导通裂隙,邻近层卸压瓦斯沿裂隙进入保护层采空区,又因采空区漏风的存在,易造成工作面上隅角瓦斯超限。为解决这一问题,提出了大直径穿层递进埋管瓦斯抽采技术,并通过FLUENT软件的模拟,得出穿层埋管的最佳间距及抽放孔的合理孔径。%After the upper protective seam being mined, along with the roof and floor moving and falling, the breakover crevasse would be formed in the coal rock layer between the level close to the ledger wall and the protective seam. Then with the decompression of the neighbor level, the gas enters the protective worked - out section through the crevasse. Owing to the existence of leak in the worked - out section, it's easy to cause the working surface comer gas ultra to limit. The technology of progressive and large diameter buried drainage pipe has been put forward and the best reasonable distance and drainage hole diameter of the buried drainage pipe is obtained through the FLUENT simulation.

  17. 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...

  18. Nutrient mitigation capacity in Mississippi Delta, USA drainage ditches

    Energy Technology Data Exchange (ETDEWEB)

    Moore, M.T., E-mail: matt.moore@ars.usda.go [USDA-Agricultural Research Service National Sedimentation Laboratory, Water Quality and Ecology Research Unit, PO Box 1157, Oxford, MS 38655 (United States); Kroeger, R. [Department of Wildlife and Fisheries, Mississippi State University, Box 9690, Mississippi State, MS 39762 (United States); Locke, M.A.; Cullum, R.F.; Steinriede, R.W.; Testa, S.; Lizotte, R.E.; Bryant, C.T.; Cooper, C.M. [USDA-Agricultural Research Service National Sedimentation Laboratory, Water Quality and Ecology Research Unit, PO Box 1157, Oxford, MS 38655 (United States)

    2010-01-15

    Eutrophication and hypoxia within aquatic systems are a serious international concern. Various management practices have been proposed to help alleviate nutrient loads transported to the Gulf of Mexico and other high-profile aquatic systems. The current study examined the nutrient mitigation capacity of a vegetated (V) and non-vegetated (NV) agricultural drainage ditch of similar size and landform in the Mississippi Delta. While no statistically significant differences in ammonium, nitrate, or dissolved inorganic phosphorus mitigation between the two ditches existed, there were significant differences in total inorganic phosphorus percent load reductions (V: 36% +- 4; NV: 71% +- 4). However, both agricultural drainage ditches were able to mitigate nutrients, thus reducing the load reaching downstream aquatic receiving systems. Further studies examining ecosystem dynamics within drainage ditches such as sediment and plant nutrient partitioning, as well as microbial processes involved, are needed to provide a better understanding of natural nutrient variability, seasonality and flux. - Agricultural drainage ditches reduce N and P runoff concentrations from production landscapes.

  19. 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...

  20. 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.

  1. Multi-Objective Optimization for Urban Drainage Rehabilitation

    NARCIS (Netherlands)

    Barreto Cordero, W.J.

    2012-01-01

    Flooding in urbanized areas has become a very important issue around the world. The level of service (or performance) of urban drainage systems (UDS) degrades in time for a number of reasons. In order to maintain an acceptable performance of UDS, early rehabilitation plans must be developed and impl

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

    International Nuclear Information System (INIS)

    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

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

    NARCIS (Netherlands)

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

    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

  4. Assessment of Agricultural Drainage Pipe Conditions Using Ground Penetrating Radar

    Science.gov (United States)

    Farmers and land improvement contractors, especially in the Midwest U.S., need methods to not only locate buried agricultural drainage pipe, but also to determine if the pipes are functioning properly with respect to water delivery. Previous investigations have already demonstrated the feasibility o...

  5. Groundwater pollution by nitrates in irrigated areas with drainage

    International Nuclear Information System (INIS)

    Field studies were conducted at three selected sites in irrigated areas of Pakistan to assess magnitude and severity of groundwater pollution by nitrates. The results of these studies indicate that concentration of nitrates in most of the samples collected from irrigated areas having drainage facility is much lower than threshold limit. The nitrate-nitrogen level within drainage projects ranges from 0.01-9.00 mg/l and in the area without drainage system ranges from 10.1-12.5 mg/l. The mineral fertilizers though are making contribution of NO3-N to the groundwater sources but that is much lower than threshold limits. The presence of septic tanks or farmyard manure dumps is also significant contributors of NO3-N to the groundwater. Thus drinking water sources near these polluting points are probable danger to human health. It is, therefore, concluded that still there is a lot of potential for fertilizer use in the agriculture but proper drainage facilities should be provided to minimize the potential threat of NO/sub 3/ pollution. (author)

  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. Models Robustness for Simulating Drainage and NO3-N Fluxes

    Science.gov (United States)

    Jabro, Jay; Jabro, Ann

    2013-04-01

    Computer models simulate and forecast appropriate agricultural practices to reduce environmental impact. The objectives of this study were to assess and compare robustness and performance of three models -- LEACHM, NCSWAP, and SOIL-SOILN--for simulating drainage and NO3-N leaching fluxes in an intense pasture system without recalibration. A 3-yr study was conducted on a Hagerstown silt loam to measure drainage and NO3-N fluxes below 1 m depth from N-fertilized orchardgrass using intact core lysimeters. Five N-fertilizer treatments were replicated five times in a randomized complete block experimental design. The models were validated under orchardgrass using soil, water and N transformation rate parameters and C pools fractionation derived from a previous study conducted on similar soils under corn. The model efficiency (MEF) of drainage and NO3-N fluxes were 0.53, 0.69 for LEACHM; 0.75, 0.39 for NCSWAP; and 0.94, 0.91for SOIL-SOILN. The models failed to produce reasonable simulations of drainage and NO3-N fluxes in January, February and March due to limited water movement associated with frozen soil and snow accumulation and melt. The differences between simulated and measured NO3-N leaching and among models' performances may also be related to soil N and C transformation processes embedded in the models These results are a monumental progression in the validation of computer models which will lead to continued diffusion across diverse stakeholders.

  8. 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...

  9. 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.

  10. 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 was p...

  11. 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

  12. 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

  13. Nutrient export in tile drainage: Comparing manure injection to fertigation

    Science.gov (United States)

    Subsurface tile drainage of agricultural land is implicated as a major source of nutrients to the Mississippi River. To protect water quality, land application of manure should maximize crop nutrient use and minimize nutrient loss. Weather constraints and regulations restrict the period during which...

  14. Global warming and drainage development: perspective and challenges

    NARCIS (Netherlands)

    Wrachien, De D.; Feddes, R.A.

    2004-01-01

    The report gives an overview of current and future (time horizon 2025) drainage developments around the world. Moreover, the paper analyses the results of four of the most advanced global circulation models for assessing the hydrological impact of global warming, due to the greenhouse effect, on the

  15. Why does inverse modeling of drainage inventories work?

    Science.gov (United States)

    White, Nicky; Roberts, Gareth

    2016-04-01

    We describe and apply a linear inverse model which calculates spatial and temporal patterns of uplift rate by minimizing the misfit between inventories of observed and predicted longitudinal river profiles. This approach builds upon a more general, non-linear, optimization model, which suggests that shapes of river profiles are dominantly controlled by upstream advection of kinematic waves of incision produced by spatial and temporal changes in regional uplift rate. We have tested both algorithms by inverting thousands of river profiles from Africa, Eurasia, the Americas, and Australia. For each continent, the drainage network was constructed from a digital elevation model and the fidelity of river profiles extracted from this network was carefully checked using satellite imagery. Spatial and temporal patterns of both uplift rate and cumulative uplift were calibrated using independent geologic and geophysical observations. Inverse modeling of these substantial inventories of river profiles suggests that drainage networks contain coherent signals that record the regional growth of elevation. In the second part of this presentation, we use spectral analysis of river profiles to suggest why drainage networks behave in a coherent, albeit non-linear, fashion. Our analysis implies that large-scale topographic signals injected into landscapes generate spectral slopes that are usually red (i.e. Brownian). At wavelengths shorter than tens of km, spectral slopes whiten which suggests that coherent topographic signals cease to exist at these shorter length scales. Our results suggest that inverse modeling of drainage networks can reveal useful information about landscape growth through space and time.

  16. 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.

  17. Nutrient mitigation capacity in Mississippi Delta, USA drainage ditches

    International Nuclear Information System (INIS)

    Eutrophication and hypoxia within aquatic systems are a serious international concern. Various management practices have been proposed to help alleviate nutrient loads transported to the Gulf of Mexico and other high-profile aquatic systems. The current study examined the nutrient mitigation capacity of a vegetated (V) and non-vegetated (NV) agricultural drainage ditch of similar size and landform in the Mississippi Delta. While no statistically significant differences in ammonium, nitrate, or dissolved inorganic phosphorus mitigation between the two ditches existed, there were significant differences in total inorganic phosphorus percent load reductions (V: 36% ± 4; NV: 71% ± 4). However, both agricultural drainage ditches were able to mitigate nutrients, thus reducing the load reaching downstream aquatic receiving systems. Further studies examining ecosystem dynamics within drainage ditches such as sediment and plant nutrient partitioning, as well as microbial processes involved, are needed to provide a better understanding of natural nutrient variability, seasonality and flux. - Agricultural drainage ditches reduce N and P runoff concentrations from production landscapes.

  18. 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...

  19. 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.)

  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. 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.

  2. Liouvillian perturbations of black holes

    Science.gov (United States)

    Couch, W. E.; Holder, C. L.

    2007-10-01

    We apply the well-known Kovacic algorithm to find closed form, i.e., Liouvillian solutions, to the differential equations governing perturbations of black holes. Our analysis includes the full gravitational perturbations of Schwarzschild and Kerr, the full gravitational and electromagnetic perturbations of Reissner-Nordstrom, and specialized perturbations of the Kerr-Newman geometry. We also include the extreme geometries. We find all frequencies ω, in terms of black hole parameters and an integer n, which allow Liouvillian perturbations. We display many classes of black hole parameter values and their corresponding Liouvillian perturbations, including new closed-form perturbations of Kerr and Reissner-Nordstrom. We also prove that the only type 1 Liouvillian perturbations of Schwarzschild are the known algebraically special ones and that type 2 Liouvillian solutions do not exist for extreme geometries. In cases where we do not prove the existence or nonexistence of Liouvillian perturbations we obtain sequences of Diophantine equations on which decidability rests.

  3. 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.

  4. Energy on black hole spacetimes

    CERN Document Server

    Corichi, Alejandro

    2012-01-01

    We consider the issue of defining energy for test particles on a background black hole spacetime. We revisit the different notions of energy as defined by different observers. The existence of a time-like isometry allows for the notion of a total conserved energy to be well defined, and subsequently the notion of a gravitational potential energy is also meaningful. We then consider the situation in which the test particle is adsorbed by the black hole, and analyze the energetics in detail. In particular, we show that the notion of horizon energy es defined by the isolated horizons formalism provides a satisfactory notion of energy compatible with the particle's conserved energy. As another example, we comment a recent proposal to define energy of the black hole as seen by an observer at rest. This account is intended to be pedagogical and is aimed at the level of and as a complement to the standard textbooks on the subject.

  5. 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.

  6. Constraints on Black Hole Remnants

    CERN Document Server

    Giddings, Steven B

    1994-01-01

    One possible fate of information lost to black holes is its preservation in black hole remnants. It is argued that a type of effective field theory describes such remnants (generically referred to as informons). The general structure of such a theory is investigated and the infinite pair production problem is revisited. A toy model for remnants clarifies some of the basic issues; in particular, infinite remnant production is not suppressed simply by the large internal volumes as proposed in cornucopion scenarios. Criteria for avoiding infinite production are stated in terms of couplings in the effective theory. Such instabilities remain a problem barring what would be described in that theory as a strong coupling conspiracy. The relation to euclidean calculations of cornucopion production is sketched, and potential flaws in that analysis are outlined. However, it is quite plausible that pair production of ordinary black holes (e.g. Reissner Nordstrom or others) is suppressed due to strong effective couplings....

  7. Massive Black Holes and Galaxies

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun. I will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.

  8. 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.

  9. 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.

  10. Time dependent black holes and scalar hair

    International Nuclear Information System (INIS)

    We show how to correctly account for scalar accretion onto black holes in scalar field models of dark energy by a consistent expansion in terms of a slow roll parameter. At leading order, we find an analytic solution for the scalar field within our Hubble volume, which is regular on both black hole and cosmological event horizons, and compute the back reaction of the scalar on the black hole, calculating the resulting expansion of the black hole. Our results are independent of the relative size of black hole and cosmological event horizons. We comment on the implications for more general black hole accretion, and the no hair theorems. (paper)

  11. Implementing black hole as efficient power plant

    OpenAIRE

    Wei, Shao-Wen; Liu, Yu-Xiao

    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 w...

  12. 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.

  13. 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.

  14. Control of black hole evaporation?

    International Nuclear Information System (INIS)

    Contradiction between Hawking's semi-classical arguments and the string theory on the evaporation of a black hole has been one of the most intriguing problems in fundamental physics. A final-state boundary condition inside the black hole was proposed by Horowitz and Maldacena to resolve this contradiction. We point out that the original Hawking effect can also be regarded as a separate boundary condition at the event horizon for this scenario. Here, we found that the change of the Hawking boundary condition may affect the information transfer from the initial collapsing matter to the outgoing Hawking radiation during the evaporation process and as a result the evaporation process itself, significantly

  15. Black holes and warped spacetime

    International Nuclear Information System (INIS)

    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

  16. Falling into a black hole

    OpenAIRE

    Mathur, Samir D.

    2007-01-01

    String theory tells us that quantum gravity has a dual description as a field theory (without gravity). We use the field theory dual to ask what happens to an object as it falls into the simplest black hole: the 2-charge extremal hole. In the field theory description the wavefunction of a particle is spread over a large number of `loops', and the particle has a well-defined position in space only if it has the same `position' on each loop. For the infalling particle we find one definition of ...

  17. 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)

  18. Asymptotic black hole quasinormal frequencies

    OpenAIRE

    Motl, Lubos; Neitzke, Andrew

    2003-01-01

    We give a new derivation of the quasinormal frequencies of Schwarzschild black holes in d greater than or equal to 4 and Reissner-Nordstrom black holes in d = 4, in the limit of infinite damping. For Schwarzschild in d greater than or equal to 4 we find that the asymptotic real part is THawkinglog(3) for scalar perturbations and for some gravitational perturbations; this confirms a result previously obtained by other means in the case d = 4. For Reissner-Nordstrom in d = 4 w...

  19. 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...

  20. 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 (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. PMID:24574017

  1. 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.

  2. 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.

  3. 21 CFR 878.4200 - Introduction/drainage catheter and accessories.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Introduction/drainage catheter and accessories. 878.4200 Section 878.4200 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Introduction/drainage catheter and accessories. (a) Identification. An introduction/drainage catheter is...

  4. Impacts of drainage water management on subsurface drain flow, nitrate concentration, and nitrate loads in Indiana

    Science.gov (United States)

    Drainage water management is a conservation practice that has the potential to reduce drainage outflow and nitrate (NO3) loss from agricultural fields while maintaining or improving crop yields. The goal of this study was to quantify the impact of drainage water management on dra...

  5. 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

  6. 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.

  7. 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...

  8. 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...

  9. 40 CFR 434.40 - Applicability; description of the alkaline mine drainage subcategory.

    Science.gov (United States)

    2010-07-01

    ... alkaline mine drainage subcategory. 434.40 Section 434.40 Protection of Environment ENVIRONMENTAL..., BCT LIMITATIONS AND NEW SOURCE PERFORMANCE STANDARDS Alkaline Mine Drainage § 434.40 Applicability; description of the alkaline mine drainage subcategory. The provisions of this subpart are applicable...

  10. SIMULATING LONG-TERM PERFORMANCE OF DRAINAGE WATER MANAGEMENT ACROSS THE MIDWESTERN UNITED STATES

    Science.gov (United States)

    Under conventional drainage (CVD), excess soil water in agricultural fields is allowed to drain freely through artificial subsurface drainage lines. In contrast, drainage water management (DWM) utilizes a control structure at the end of the lines to regulate drain flow by varying the depth of the d...

  11. An Optimal Balance between Efficiency and Safety of Urban Drainage Networks

    Science.gov (United States)

    Seo, Y.

    2014-12-01

    Urban drainage networks have been developed to promote the efficiency of a system in terms of drainage time so far. Typically, a drainage system is designed to drain water from developed areas promptly as much as possible during floods. In this regard, an artificial drainage system have been considered to be more efficient compared to river networks in nature. This study examined artificial drainage networks and the results indicate they can be less efficient in terms of network configuration compared with river networks, which is counter-intuitive. The case study of 20 catchments in Seoul, South Korea shows that they have wide range of efficiency in terms of network configuration and consequently, drainage time. This study also demonstrates that efficient drainage networks are more sensitive to spatial and temporal rainfall variation such as rainstorm movement. Peak flows increase more than two times greater in effective drainage networks compared with inefficient and highly sinuous drainage networks. Combining these results, this study implies that the layout of a drainage network is an important factor in terms of efficient drainage and also safety in urban catchments. Design of an optimal layout of the drainage network can be an alternative non-structural measures that mitigate potential risks and it is crucial for the sustainability of urban environments.

  12. The first massive black holes

    OpenAIRE

    Volonteri, Marta

    2012-01-01

    I briefly outline recent theoretical developments on the formation of the first massive black holes (MBHs) that may grow into the population of MBHs powering quasars and inhabiting galactic centers today. I also touch upon possible observational tests that may give insights on what the properties of the first MBHs were.

  13. 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.

  14. Extremal Higher Spin Black Holes

    CERN Document Server

    Bañados, Máximo; Faraggi, Alberto; Jottar, Juan I

    2015-01-01

    The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require nor implies the existence of supersymmetry, we exemplify its consequences in the context of sl(3|2) + sl(3|2) Chern-Simons theory. Remarkably, while as usual not all extremal solutions preserve supersymmetries, we find that the higher spin setup allows for non-extremal supersymmetric black hole solutio...

  15. 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.

  16. 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.

  17. 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.

  18. 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 ...

  19. Close encounters of black holes

    CERN Document Server

    Giulini, D

    2003-01-01

    This is an introduction into the problem of how to set up black hole initial-data for the matter-free field equations of General Relativity. The approach is semi-pedagogical and addresses a more general audience of astrophysicists and students with no specialized training in General Relativity beyond that of an introductory lecture.

  20. 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…

  1. 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.

  2. Brief History of Black-Holes

    CERN Document Server

    Berman, M S

    2004-01-01

    We show that the gravitational collapse of a black-hole terminates in the birth of a white-hole, due to repulsive gravitation (antigravitation); in particular, the infinite energy density singularity does NOT occur.

  3. 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.

  4. 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

  5. An Introduction to Black Hole Evaporation

    OpenAIRE

    Traschen, Jennie

    2000-01-01

    Classical black holes are defined by the property that things can go in, but don't come out. However, Stephen Hawking calculated that black holes actually radiate quantum mechanical particles. The two important ingredients that result in back hole evaporation are (1) the spacetime geometry, in particular the black hole horizon, and (2) the fact that the notion of a "particle" is not an invariant concept in quantum field theory. These notes contain a step-by-step presentation of Hawking's calc...

  6. Modified dispersion relations and black hole physics

    OpenAIRE

    Ling, Yi; Hu, Bo; Li, Xiang

    2005-01-01

    A modified formulation of energy-momentum relation is proposed in the context of doubly special relativity. We investigate its impact on black hole physics. It turns out that such modification will give corrections to both the temperature and the entropy of black holes. In particular this modified dispersion relation also changes the picture of Hawking radiation greatly when the size of black holes approaching the Planck scale. It can prevent black holes from total evaporation, as a result pr...

  7. Black-hole formation from stellar collapse

    International Nuclear Information System (INIS)

    I review the end-state of massive stellar evolution, following the evolution of these massive stars from the onset of collapse through the formation of a compact remnant and the possible supernova or hypernova explosion. In particular, I concentrate on the formation of black holes from stellar collapse: the fraction of stars that form black holes, the black-hole mass distribution and the velocities these black-hole remnants may receive during their formation process

  8. Rotating Black Holes in Higher Dimensions

    CERN Document Server

    Kleihaus, Burkhard; Navarro-Lerida, Francisco

    2007-01-01

    The properties of higher-dimensional black holes can differ significantly from those of black holes in four dimensions, since neither the uniqueness theorem, nor the staticity theorem or the topological censorship theorem generalize to higher dimensions. We first discuss black holes of Einstein-Maxwell theory and Einstein-Maxwell-Chern-Simons theory with spherical horizon topology. Here new types of stationary black holes are encountered. We then discuss nonuniform black strings and present evidence for a horizon topology changing transition.

  9. Rotating Black Holes in Higher Dimensions

    Science.gov (United States)

    Kleihaus, Burkhard; Kunz, Jutta; Navarro-Lérida, Francisco

    2008-03-01

    The properties of higher-dimensional black holes can differ significantly from those of black holes in four dimensions, since neither the uniqueness theorem, nor the staticity theorem or the topological censorship theorem generalize to higher dimensions. We first discuss black holes of Einstein-Maxwell theory and Einstein-Maxwell-Chern-Simons theory with spherical horizon topology. Here new types of stationary black holes are encountered. We then discuss nonuniform black strings and present evidence for a horizon topology changing transition.

  10. Supermassive Black Holes and Their Environments

    OpenAIRE

    Colberg, Joerg M.; Di Matteo, Tiziana

    2008-01-01

    We make use of the first high--resolution hydrodynamic simulations of structure formation which self-consistently follows the build up of supermassive black holes introduced in Di Matteo et al. (2007) to investigate the relation between black holes (BH), host halo and large--scale environment. There are well--defined relations between halo and black hole masses and between the activities of galactic nuclei and halo masses at low redshifts. A large fraction of black holes forms anti--hierarchi...

  11. Black hole growth in hierarchical galaxy formation.

    OpenAIRE

    Malbon, R. K.; Baugh, C M; Frenk, C. S.; Lacey, C. G.

    2007-01-01

    We incorporate a model for black hole growth during galaxy mergers into the semi-analytical galaxy formation model based on Lambda-CDM proposed by Baugh et al. (2005). Our black hole model has one free parameter, which we set by matching the observed zeropoint of the local correlation between black hole mass and bulge luminosity. We present predictions for the evolution with redshift of the relationships between black hole mass and bulge properties. Our simulations reproduce the evolution of ...

  12. Energy conservation for dynamical black holes

    OpenAIRE

    Hayward, Sean A.

    2004-01-01

    An energy conservation law is described, expressing the increase in mass-energy of a general black hole in terms of the energy densities of the infalling matter and gravitational radiation. For a growing black hole, this first law of black-hole dynamics is equivalent to an equation of Ashtekar & Krishnan, but the new integral and differential forms are regular in the limit where the black hole ceases to grow. An effective gravitational-radiation energy tensor is obtained, providing measures o...

  13. Noncommutative geometry inspired Schwarzschild black hole

    OpenAIRE

    Nicolini, Piero; Smailagic, Anais; Spallucci, Euro

    2005-01-01

    We investigate the behavior of a noncommutative radiating Schwarzschild black hole. It is shown that coordinate noncommutativity cures usual problems encountered in the description of the terminal phase of black hole evaporation. More in detail, we find that: the evaporation end-point is a zero temperature extremal black hole even in the case of electrically neutral, non-rotating, objects; there exists a finite maximum temperature that the black hole can reach before cooling down to absolute ...

  14. Residual stress field of ballised holes

    International Nuclear Information System (INIS)

    Ballising, involving pushing a slightly over-sized ball made of hard material through a hole, is a kind of cold working process. Applying ballising process to fastener holes produces compressive residual stress on the edge of the holes, and therefore increases the fatigue life of the components or structures. Quantification of the residual stress field is critical to define and precede the ballising process. In this article, the ballised holes are modeled as cold-expanded holes. Elastic-perfectly plastic theory is employed to analyze the holes with cold expansion process. For theoretical simplification, an axially symmetrical thin plate with a cold expanded hole is assumed. The elasticplastic boundaries and residual stress distribution surrounding the cold expanded hole are derived. With the analysis, the residual stress field can be obtained together with actual cold expansion process in which only the diameters of hole before and after cold expansion need to be measured. As it is a non-destructive method, it provides a convenient way to estimate the elastic-plastic boundaries and residual stresses of cold worked holes. The approach is later extended to the case involving two cold-worked holes. A ballised hole is looked upon as a cold expanded hole and therefore is investigated by the approach. Specimens ballised with different interference levels are investigated. The effects of interference levels and specimen size on residual stresses are studied. The overall residual stresses of plates with two ballised holes are obtained by superposing the residual stresses induced on a single ballised hole. The effects of distance between the centers of the two holes with different interference levels on the residual stress field are revealed

  15. Extremal higher spin black holes

    Science.gov (United States)

    Bañados, Máximo; Castro, Alejandra; Faraggi, Alberto; Jottar, Juan I.

    2016-04-01

    The gauge sector of three-dimensional higher spin gravities can be formulated as a Chern-Simons theory. In this context, a higher spin black hole corresponds to a flat connection with suitable holonomy (smoothness) conditions which are consistent with the properties of a generalized thermal ensemble. Building on these ideas, we discuss a definition of black hole extremality which is appropriate to the topological character of 3 d higher spin theories. Our definition can be phrased in terms of the Jordan class of the holonomy around a non-contractible (angular) cycle, and we show that it is compatible with the zero-temperature limit of smooth black hole solutions. While this notion of extremality does not require supersymmetry, we exemplify its consequences in the context of sl(3|2) ⊕ sl(3|2) Chern-Simons theory and show that, as usual, not all extremal solutions preserve supersymmetries. Remarkably, we find in addition that the higher spin setup allows for non-extremal supersymmetric black hole solutions. Furthermore, we discuss our results from the perspective of the holographic duality between sl(3|2) ⊕ sl(3|2) Chern-Simons theory and two-dimensional CFTs with W (3|2) symmetry, the simplest higher spin extension of the N = 2 super-Virasoro algebra. In particular, we compute W (3|2) BPS bounds at the full quantum level, and relate their semiclassical limit to extremal black hole or conical defect solutions in the 3 d bulk. Along the way, we discuss the role of the spectral flow automorphism and provide a conjecture for the form of the semiclassical BPS bounds in general N = 2 two-dimensional CFTs with extended symmetry algebras.

  16. 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.

  17. Signatures of black holes at the LHC

    OpenAIRE

    Cavaglia, Marco; Godang, Romulus; 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.

  18. 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...

  19. 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.

  20. Scalar field radiation from dilatonic black holes

    Science.gov (United States)

    Gohar, H.; Saifullah, K.

    2012-12-01

    We study radiation of scalar particles from charged dilaton black holes. The Hamilton-Jacobi method has been used to work out the tunneling probability of outgoing particles from the event horizon of dilaton black holes. For this purpose we use WKB approximation to solve the charged Klein-Gordon equation. The procedure gives Hawking temperature for these black holes as well.